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  • Autoradiography  (67)
  • Light and electron microscopy  (47)
  • Innervation  (42)
  • Synapses  (37)
  • Springer  (190)
  • 2005-2009
  • 1970-1974  (190)
  • 1950-1954
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 10 (1972), S. 23-30 
    ISSN: 1432-0827
    Keywords: Bone ; Microradiography ; Autoradiography ; Preparation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La préparation de coupes fines, plano-parallèles d'os non décalcifié, d'épaisseur connue, pour la réalisation de microradiographies et d'autoradiographies quantitatives est décrite. Pour éviter que des fractures de l'os se produisent, le fragment osseux fixé doit être inclus dans un matériel approprié qui ne doit pas se rétracter. Un minimum de force doit être appliqué à l'échantillon pendant la coupe pour éviter des vibrations. La méthode décrite, utilisant une scie circulaire tournant à faible vitesse, est adéquate. Le polissage final des surfaces du specimen est réalisé sur une machine à polir modifiée. On peut préparer un grand nombre de coupes en relativement peu de temps pour des études statistiques.
    Abstract: Zusammenfassung Die Herstellung von dünnen, parallelgestellten Schnitten von unentkalktem Knochen bekannter Dicke zur quantitativen Auto- und Mikroradiographie wird beschrieben. Der Knochen hat die Tendenz, unter Druck zu brechen. Um diese Schwierigkeit zu überwinden, ist es sehr wichtig, daß die fixierte Knochenprobe genügend vom Einbettungsmaterial durchdrungen wird und daß das Einschlußmittel sich vom Knochenrand weg kontrahiert. Beim Schneiden darf nur ein minimaler Druck auf die Probe ausgeübt werden, damit der Knochen nicht zertrümmert wird. Die beschriebene Methode, bei welcher eine spezielle Einrichtung zum Auftropfen des Schmiermittels den Gebrauch einer langsam rotierenden Kreissäge ermöglichte, erwies sich als günstig. Das schließliche Polieren der Oberflächen der Proben wurde auf einer modifizierten Schleifmaschine ausgeführt. Mit dieser Methode kann eine große Anzahl von Schnitten in relativ kurzer Zeit hergestellt werden; dies ist sehr wichtig, um eine angemessene Anzahl von Proben für statistische Analysen zu erhalten.
    Notes: Abstract The preparation of thin, parallel-sided sections of undecalcified bone of known thickness for quantitative auto- and micro-radiography is described. To overcome the tendency of the bone to fracture when stressed, it is essential that the fixed sample of bone should be adequately penetrated by the embedding material and that the mounting material should not contract away from the edge of the bone. Minimum stress must be applied to the sample when cutting or the bone may be shattered. The method described, using a gravity feed to a low speed circular saw, has been found to be suitable. Final polishing of the surfaces of the specimen was carried out on a modified lapping machine. Large numbers of sections can be prepared in a relatively short time by the method and this is essential to obtain an adequate number of samples for statistical analysis.
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  • 2
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    Calcified tissue international 12 (1973), S. 169-173 
    ISSN: 1432-0827
    Keywords: Calcification ; Histochemistry ; Autoradiography ; Fetal ; Mandible
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des rats femelles reçoivent du45Ca ou du32P au 13ème et 18ème jour de la grossesse. Les coupes sériées des têtes de foetus sont étudiées par autoradiographie et par diverses méthodes histologiques pour déterminer la calcification. La détection la plus précoce de45Ca s'observe simultanément comme une réaction positive pour le calcium avec une des méthodes histologiques utilisées.32P est en évidence par les méthodes autoradiographiques un peu plus tard que le45Ca et sa présence coincide avec la réaction positive la plus précoce observée avec les autres méthodes histologiques utilisées. Les os de ces têtes foetales commencent à se calcifier selon un mode particulier commençant par la mandibule, puis l'os frontal et le maxillaire supérieur, suivis par les os nasaux, pariétaux et interpariétaux.
    Abstract: Zusammenfassung Weibliche Ratten erhielten45Ca und32P zwischen dem 13.–18. Tag der Schwangerschaft. Zur Ermittlung der Verkalkung wurden Serienschnitte der Köpfe ihrer Feten mittels Autoradiographie sowie durch verschiedene histologische Methoden untersucht. Das erste Auftreten von45Ca war ebenfalls von einer positiven Calciumreaktion mittels einer der verwendeten histologischen Methoden begleitet.32P wurde in der Autoradiographie erst etwas später als45Ca festgestellt und dessen Nachweis deckte sich mit den ersten positiven Reaktonen aller anderen verwendeten histologischen Methoden. Die Knochen in diesen Fetusköpfen begannen in einer bestimmten Sequenz zu verkalken: zuerst der Unterkiefer, dann das Stirnbein und der Oberkiefer, dann das Nasenbein, die Parietal- und Interparietalknochen.
    Notes: Abstract Female rats were given45Ca or32P from 13 to 18 days of pegnancy. Serial sections from the heads of their fetuses were studied by autoradiography, as well as by several histological methods for assessing calcification. The earliest detection of45calcium occured at the same time as a positive reaction for calcium with one of the histological methods used.32P was not detectable by autoradiographic methods until somewhat later than45Ca, and its presence coincided with the earliest positive reaction with all of the other histological methods employed. The bones in these fetal heads began to calcify in a partcular sequence, the mandible first, then the frontal bone and maxilla, followed by the nasal, parietal and interparietal bones.
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  • 3
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    Calcified tissue international 7 (1971), S. 114-132 
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Sodium-deficiency ; Histology ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Ce travail étudie les effets d'une carence en sodium sur le squelette chez le Rat en croissance. Il a été effectué sur 3 groupes de Rats: groupe carencé, groupe témoin sous-nutri et groupe témoin normal. L'étude macroradiographique et microradiographique des tibias révèle que la carence en sodium provoque en 8 semaines une diminution de la longueur, un amincissement de l'espace métaphyso-épiphysaire et l'apparition d'une ostéopénie. Cette ostéopénie prédomine sur la métaphyse par rapport à la diaphyse. Au niveau de celle-ci, le rapport cortico-diaphysaire est diminué. Ce changement est essentiellement dû à l'amincissement de l'os cortical par sa face périphérique. Le marquage par la tétracycline confirme cette atteinte prédominante de l'apposition périostée. L'étude histologique et l'étude autoradiographique suggèrent que cette ostéopénie résulte d'un important ralentissement de l'ostéogénèse et de l'activité globale du tissu osseux. L'analyse chimique révèle des changements minimes de la composition des fémurs. La teneur en cendres est légèrement abaissée. La rapport Ca/P est légèrement augmenté. Les rapports Ca/N et P/N sont diminués. Le rapport Na/Ca est augmenté. Les mécanismes possibles de cette atteinte squelettique sont envisagés: sous-nutrition, effet acidifiant du régime, trouble de l'absorption intestinale du calcium, retentissement surrénal et conséquences cellulaires de la carence en sodium. En conclusion, dans le déterminisme de l'atteinte osseuse semblent devoir être retenus: a) l'inanition dûe à l'anorexie provoquée par le régime désodé, b) und effet squelettique propre de la carence en sodium, le trouble de l'absorption intestinale du calcium ne paraissant pas jouer un rôle déclenchant.
    Abstract: Zusammenfassung In dieser Arbeit wurde der Einfluß eines Natriummangels auf das Skelet der noch wachsenden Ratte beobachtet. Die Studie betrifft drei Gruppen von Ratten: eine mit Natriummangel, eine normal ernährte und eine unterernährte Kontrollgruppe. Die makro- und mikroradiographische Untersuchung der Tibiae nach 8wöchigem Natriummangel zeigt eine Verkürzung, eine Verringerung des metaphyso-epiphysären Intervalls und eine Osteopenie, die in der Metaphyse merkbarer als in der Diaphyse ist. Das corticodiaphysische Verhältnis ist herabgesetzt, und zwar verjüngt sich der Knochencortex peripherisch. Mit markiertem Tetracyclin wird bewiesen, daß vorwiegend die periphere Knochenbildung betroffen ist. Die histologische und autoradiographische Untersuchung erlaubt die Annahme, daß diese Osteopenie auf stark verlangsamte Knochenbildung und gesamte metabolische Tätigkeit des Knochengewebes zurückzuführen ist. Die chemische Analyse weist unerhebliche Änderungen der Zusammensetzung der Femora auf. Der Aschengehalt ist leicht vermindert. In den Epiphysen ist Ca/P leicht erhöht. Ca/N und P/N sind herabgesetzt. Na/Ca ist wenig verändert. Die möglichen Mechanismen dieser Skeletveränderungen werden erörtert: Unterernährung, diätbedingte Säurebildung, Störung der intestinalen Calciumabsorption, Nebennieren-beeinflussung und Zellstoffwechselveränderungen durch Natriummangel. Zusammenfassend scheint hauptsächlich die Unterernährung eine Rolle zu spielen. Dazu kommen die direkten Folgen des Natriummangels auf den intestinalen Zucker- und Aminosäurentransport.
    Notes: Abstract The effects of sodium deficiency on the skeleton were studied in growing rats assigned to 3 groups: sodium deficient group, pair-fed controls, normal controls. Macroradiographic and microradiographic examinations and measurements of the tibia demonstrated that sodium deficiency after 8 weeks resulted in shorter bones, thinner cartilage and osteopenia. This osteopenia was greater in metaphysis than in diaphysis. However the cortico-diaphyseal ratio decreased, resulting from cortical bone thinning by the periosteal side. Histologic and autoradiographic examinations suggested that this osteopenia resulted from a marked slowing down of osteogenesis and total bone turnover. The mineral composition of the femur was little changed. The ash rate, Ca/N and P/N ratios decreased slightly. The Ca/P ratio increased slightly. The Na/Ca ratio increased also. The following possible mechanisms of skeletal damage were considered: undernutrition, acidifying effect of diet, fall of calcium intestinal absorption, adrenal and cellular changes resulting from the sodium deficiency. In conclusion, the bone lesions appear to be caused by undernutrition and in addition by a skeletal effect specifically due to sodium deficiency.
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  • 4
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    Calcified tissue international 8 (1971), S. 121-132 
    ISSN: 1432-0827
    Keywords: Calcium ; Skeleton ; Autoradiography ; Isotope ; Deposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Le taux de formation osseuse d'un chien adulte a été déterminé en divers endroits, en utilisant deux marqueurs à la tétracycline. Les valeurs obtenues ont été comparées avec des mesures similaires de dépôts calciques, obtenues par45Ca. Les mesures du ≪marquage diffus≫ de45Ca ont également été réalisées en utilisant l'autoradiographie quantitative. Les résultats ont été comparés avec les études similaires de Leeet coll. (J. Bone Joint Surg.47B, 157, 1965), effectuées à l'aide d'un chien nouveau-né et d'un chien adolescent. Il apparait ainsi que les études au45Ca permettent de mesurer la formation osseuse chez les chiens d'âges différents. Cependant, il est probable que le ≪marquage diffus≫ de calcium marqué chez l'Homme rend difficile la mesure du dépôt de calcium.
    Abstract: Zusammenfassung Die Geschwindigkeit der Knochenbildung bei einem ausgewachsenen Hund wurde mittels 2 Tetracyclinmarkierungen an verschiedenen Stellen des Knochens gemessen. Durch Messungen der Calciumzuwachsrate mittels45Ca-Tracer konnten die Werte beider Methoden verglichen werden. Die „diffuse Markierung” von45Ca wurde anhand von quantitativer Autoradiographie ebenfalls gemessen. Die Resultate wurden mit denjenigen ähnlicher Studien ausgewachsener Hund verwendet wurden. Es wird daraus geschlossen, daß die Knochenbildungsgeschwindigkeit von Hunden aller Altersstufen anhand von45Ca-Tracer-Studien gemessen werden kann. Es ist jedoch wahrscheinlich, daß die „diffuse Makierung” mit Tracer-Calcium beim Menschen zu einer schwierigen Interpretation der Messung der Calciumzuwachsrate führt.
    Notes: Abstract The bone formation rate of an adult dog has been found at several bone sites using two tetracycline markers. The values found have been compared with similar measurements of calcium accretion rate using45Ca as a tracer. Measurements of the “diffuse label” of45Ca were also made using quantitative autoradiography. The results have been compared with similar studies by Leeet al. (J. Bone Joint Surg.47 B, 157, 1965) using a puppy and an adolescent dog. It is concluded that45Ca tracer studies can measure the bone formation rate of dogs at any age. However, it is probable that the “diffuse label” uptake of tracer calcium in humans makes the calcium accretion rate measurement difficult to interpret.
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  • 5
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    Calcified tissue international 7 (1971), S. 201-211 
    ISSN: 1432-0827
    Keywords: Autoradiography ; Calcium ; Oviduct ; Shell-gland
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La localisation cellulaire du calcium de la muqueuse de l'oviducte d'oiseaux a été étudiée par autoradiographie au45Ca, à partir de tissus préparés soit par incubation dans le45Ca, soit par injection intraveneuse du45Ca. La congélation — substitution est utilisée pour retenir le calcium aisément diffusible dans le tissu. L'épithelium cylindrique de la glande de la coquille s'enrichit significativement plus en45Cain vitro, en fonction de l'augmentation du temps d'incubation, de une à dix minutes et/ou en élevant la température de 0° à 42°. Ces effets sont diminués par l'adjonction de dinitrophenol au milieu d'incubation. Les glandes tubulaires de ce tissu réagissent à peine. Généralement, après injection intravenieuse de45Ca, la glande de la coquille retient plus de radionuclide que les autres régions de l'oviducte. Lorsqu'une coquille d'œuf est en voie de calcification, l'épithelium cylindrique de cette glande contient plus de grains que les glandes tubulaires, mais, en cas d'absence de formation d'œuf, le nombre de grains est identique dans les 2 types cellulaires. Il semble que l'épithélium cylindrique de la glande de la coquille a une affinité plus grande et plus variable pour le45Ca que la glande de la coquille les glandes tutulaires ou les cellules muqueuses d'autres régions de l'oviducte. Ces résultats indiquent sans le prouver, que l'épithélium cylindrique est plus actif dans le transfert du calcium des vaisseaux sanguins vers la lumière de la glande de la coquille.
    Abstract: Zusammenfassung Die celluläre Verteilung von Calcium in der Eileitermucosa von Hühnern wurde anhand von45Ca-Autoradiographien in Gewebe studiert, welches entweder durch Inkubation mit45Ca oder durch intravenöse Injektion von45Ca präpariert wurde. Gefriersubstitution wurde verwendet, um leicht diffundierbares Calcium im Gewebe zurückzuhalten.In vitro nahm das Cylinderepithel der Schalendrüse auffallend mehr45Ca auf, wenn die Inkubationszeit von einer auf zehn Minuten verlängert wurde und/oder wenn die Temperatur von 0° auf 42° erhöht wurde. Diese Wirkungen wurden durch die Zugabe von Dinitrophenol zum Inkubations-medium vermindert. Die Tubulärdrüsen dieses Gewebes reagierten kaum. Im allgemeinen schlossen die Schalendrüsen nach intravenöser Injektion von45Ca mehr Radionuklid ein als andere Teile des Eileiters. Wenn eine Eierschale calcifizierte, zeigte das Cylinderepithel der Schalendrüse bei der Autoradiographie eine höhere Anzahl von Silberkörnern als die Tubulärdrüsen, aber wenn keine Schale gebildet wurde, war sie bei beiden Zelltypen ähnlich. Die Resultate zeigen, daß das Cylinderepithel der Schalendrüse, eine größere und unterschiedlichere Affinität für45Ca hat als Schalendrüse Tubulärdrüsen oder Schleimhautzellen aus anderen Gebieten des Eileiters. Die Befunde deuten darauf hin, aber beweisen es nicht, daß das Cylinderepithel beim Transport von Calcium aus den Blutgefäßen in die Schalendrüse das aktivste ist.
    Notes: Abstract The cellular location of calcium in the mucosa of the avian oviduct has been studied by45Ca autoradiography in tissue prepared either by incubation with45Ca or by intravenous injection of45Ca. Freeze-substitution was used to retain easily diffusible calcium in the tissue.In vitro, columnar epithelium of the shell gland acquired significantly more45Ca as the length of incubation time was increased from one to ten minutes and/or when the temperature was raised from 0° to 42°. These effects were diminished by the addition of dinitrophenol to the incubation medium. The tubular glands of this tissue responded minimally. Genrally, after intravenous injection of45Ca, the shell gland sequestered, more radionuclide than the other regions of the oviduct. When an egg shell was being calcified, the columnar epithelium of the shell gland revealed a higher grain count than the tubular glands, but when a shell was not forming, grain counts were similar over the two types of cells. The results show that the columnar epithelium of the shell gland has a greater and more variable affinity for45Ca than have the shell gland tubular glands or mucosal cells from other regions of the oviduct. The data suggest, but do not prove, that the columnar epithelium is the most active in translocation of calcium from the blood vessels to the lumen of the shell gland.
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  • 6
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    Archives of microbiology 99 (1974), S. 255-263 
    ISSN: 1432-072X
    Keywords: Mannan Synthesis ; Saccharomyces cerevisiae ; Autoradiography ; Cell Wall ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The combination of high-resolution autoradiography and biochemical methods has been used to ascertain the site of mannan synthesis in the yeastSaccharomyces cerevisiae. High-resolution autoradiography has been performed under conditions when addedd-mannose-3H was incorporated exclusively into mannan. Application of “pulse-chase” labelling technique revealed that the radio-active mannose is fixed primarily in the cytoplasmic space from where it is transported into the cell wall. Additional experiments with separated membrane fractions from the same yeast strongly support the hypothesis that the plasmalemma is not directly involved in the biosynthesis of yeast mannan and that the membranes of the endoplasmic reticulum are the sites where the polymerization of mannosyl units takes place.
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  • 7
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    Cell & tissue research 107 (1970), S. 454-465 
    ISSN: 1432-0878
    Keywords: Cerebellum ; Neuron ; Synapses ; Myelin sheath ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In long-term organized cultures of newborn mouse cerebellum, granule cell neurons were studied with silver impregnation and electron microscopy. In silver impregnated cultures, small neurons are defined as granule cell neurons from their size, morphology and location. There are also occasional large nerve endings with the morphology typical of mossy fiber endings. In correlative electron micrographs, granule cell neurons revealed a faithful reproduction of characteristic structures seen in vivo. The fine structural details of cerebellar glomeruli and myelinated granule cell bodies developed in vitro were also described.
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  • 8
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    Cell & tissue research 107 (1970), S. 508-521 
    ISSN: 1432-0878
    Keywords: Synapses ; Axo-axonal ; Adrenergic and cholinergic terminals ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The relations between adrenergic and cholinergic terminals were studied in rat iris and rat heart with the electron microscope. Adrenergic terminals were identified by treating the animals with 5-hydroxydopamine, which produces dense-cored synaptic vesicles in adrenergic terminals in tissues fixed in glutaraldehyde and osmium. The specificity of this observation was verified. It was found that adrenergic and cholinergic nerve terminals often come in close contact with one another, the distance between the adjoining membranes being about 250 Å. At times, faint membrane thickenings could be observed in these places. The available pharmacological, physiological, and morphological evidence leaves little room for doubt that cholinergic terminal fibres can influence the adrenergic fibres. From mainly morphological evidence, it is also postulated that adrenergic terminals influence cholinergic ones.
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  • 9
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    Cell & tissue research 109 (1970), S. 46-54 
    ISSN: 1432-0878
    Keywords: Ovary ; Mouse ; Interstitial cells ; Endocrine tissue ; Innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Innervation der interstitiellen Drüse im Ovar der Maus wurde elektronenmikroskopisch untersucht. Die adrenergen Nerven wurden mit Hilfe der Falckschen Methode dargestellt. 1. Fluoreszenzmikroskopie: grün fluoreszierende Varikositäten findet man im Stroma ovarii vor allem in der näheren Umgebung von Gefäßen. Nur selten sind Nervenfasern in Komplexen von interstitiellen Zellen (IZ) zu erkennen. 2. Elektronenmikroskopie: Terminale Nervenfasern mit bekannter Innenstruktur erreichen die IZ von allen Seiten und können unabhängig von den Gefäßen verlaufen. Viele Axone durchsetzen die Basalmembran und treten in enge Beziehung zu interstitiellen Zellen. Dabei bilden sie teilweise kolbenförmige Anschwellungen nach Art von Synapsen, die tief in das Cytoplasma der innervierten Zellen eingebettet sein können. Der synaptische Spalt ist 200 Å breit. Spezialisierte prä- und postsynaptische Membranen kommen nicht vor. Die Bedeutung der Synapsen wird diskutiert.
    Notes: Summary Ultrastructural studies have been carried out on the innervation of the interstitial gland of the mouse ovary. In addition Falck's fluorescence method was applied. 1. Fluorescence microscopy: In the ovarian stroma green fluorescent nerve fibers are frequently to be found in the surroundings of large and small vessels. Seldom small fibers invade blocks of interstitial cells; however, their final ramification is not discernible. 2. Electron microscopy: Terminal fibers of the autonomic nervous system reach the cells of the interstitial gland from all sides. They may be independent from the course of the vessels. Many axons penetrate the basal membrane and come into close contact with interstitial cells, partly by forming large swellings (boutons), which may be deeply embedded into the cytoplasm of the innervated cell. The synaptic cleft is about 200 Å wide. Specialized pre- and postsynaptic membranes have not been found. The innervated cells show no peculiarities. The possible function of the synapses is discussed.
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  • 10
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    Cell & tissue research 109 (1970), S. 212-226 
    ISSN: 1432-0878
    Keywords: Ovary ; Interstitial cells ; Thecal gland ; Innervation ; Domestic fowl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the nerves of the ovarian stroma of the domestic fowl is described for the first time. In the fowl, the nerves are concentrated upon blood vessels, smoth muscles and mainly, the thecal gland with the steroid-producing cells. Myelinated as well as unmyelinated nerve fibers were observed. Numerous axon terminals representing adrenergic and also presumptive cholinergic nerve fibers are regularly seen in membranous contact with steroid-producing cells. In these axon terminals microvesicles are oriented towards the steroid-producing cells indicating a specialization of the surface from axon-to-cell contact. Evidence has been presented that there is a membranous neuro-humoral contact between the peripheral autonomie nervous system and the steroid-producing cells in the ovary. The present investigation has demonstrated that there is morphologic evidence for a nervous control of steroid-producing cells. The physiological importance of this neuro-humoral contact is discussed.
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  • 11
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    Cell & tissue research 111 (1970), S. 75-89 
    ISSN: 1432-0878
    Keywords: Lymphocytes ; Replacement rate ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Bei jugendlichen erwachsenen, weiblichen Ratten wurden der Markierungsindex und die Markierungsintensität kleiner Lymphozyten und größerer lymphoider Zellen im zirkulierenden Blut und in Lymphknoten während und nach langzeitig wiederholten Injektionen von Thymidin-3H verfolgt. Die radioaktive Vorläufersubstanz wurde in 8stündigen Intervallen über eine Zeitdauer von 30 Tagen intramuskulär verabreicht. Unter der Annahme, daß es bei diesem Verfahren zu keinen nennenswerten radiogenen, pharmakologischen oder hormonalen Störungen kam, erscheinen die nachstehenden Schluß folgerungen gerechtfertigt: 1. Während des ersten Tages der Injektionsperiode wurden im Mittel 18% (Maximum: 29%) unmarkierte kleine Lymphozyten durch markierte ersetzt. Die Markierungsindices dieser Zellart im Blut, als Funktion der Zeit nach Beginn der wiederholten Injektionen von Thymidin-3H, ergaben eine Kurve, die um den 8. Tag herum 50% und nach 30 Tagen 79% (Maximum: 85%) erreicht. 2. Die Resultate lassen sich am ehesten mit der Annahme in Einklang bringen, daß die Häufigkeitsverteilung der verschiedenen Werte für die G 0-Zeit (Erklärung im Text), bzw. Verweiloder Rezirkulationsdauer, der kleinen Lymphozyten im peripheren Blut eine kontinuierliche ist und einen Gipfel bei einem bis mehreren Tagen aufweist. 3. Die größeren lymphoiden Zellen im peripheren Blut wurden in ihrer überwiegenden Mehrzahl wesentlich rascher umgesetzt als die kleinen Lymphozyten. 4. Der Markierungsindex der kleinen Lymphozyten in Lymphknotenausstrichen entsprach am Ende der Injektionsperiode demjenigen im peripheren Blut. Am Ende der Injektionsperiode fanden sich in den äußeren Rindenschichten der Lymphknoten, wo der schwer mobilisierbare Pool von Lymphozyten liegt, mindestens ebenso viele unmarkierte kleine Lymphozyten wie im zirkulierenden Blut. 5. Die Blutmonozyten waren 4 Tage nach Beginn der wiederholten Injektionen von Thymidin-3H zu 100% markiert und behielten diesen Markierungsindex während der restlichen Injektionsperiode bei. Die Befunde werden im Zusammenhang mit Fragen des Proliferationsmodus und der Wanderungsmöglichkeiten der Lymphozyten sowie ungenügender autoradiographischer Wirksamkeit besprochen und mit den von anderen Autoren mitgeteilten Resultaten nach kontinuierlicher intravenöser Infusion von Thymidin-3H verglichen.
    Notes: Summary Young adult female Sprague-Dawley rats were given intramuscular injections of thymidine-3H at 8-hour intervals for a period of 30 days in order to follow the labeling indices and labeling intensities of small lymphocytes and of large lymphoid cells in the circulating blood and lymph nodes. Assuming that radiotoxic, pharmacological and/or hormonal effects were negligible, the following conclusions seem to be justified: 1. During the first day of the injection period the labeling index of small lymphocytes in the peripheral blood rose from zero to an average of 18% (maximum: 29%). Labeling indices of this cell type in the circulating blood, as a function of time after onset of the labeling procedure, followed a curve which reached 50% around day 8 and 79% at the 30 day terminal interval. 2. Results can best be explained by the hypothesis that the frequency distribution of the values for G 0 time or residence (recirculation) time of small lymphocytes in the circulating blood is a continuous one and shows a marked peak from one to a few days. 3. Large lymphoid cells in the peripheral blood were replaced much more rapidly than small lymphocytes. 4. The labeling index of small lymphocytes in lymph node smears at the end of the injection period corresponded to that of small blood lymphocytes. Autoradiographs of histological sections revealed that the outer zones of the lymph node cortex which contains preferentially the more sessile pool of lymphocytes, contained as high a percentage of unlabeled small lymphocytes as did the circulating blood. 5. Blood monocytes were labeled to 100% 4 days after beginning repeated injections of thymidine-3H and maintained this labeling index throughout the labeling period. These results are discussed in respect to the proliferative pattern and migrational behavior of lymphocytes and to the problem of autoradiographic inefficiency. Data are compared to those obtained with continuous intravenous infusion of thymidine-3H.
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  • 12
    ISSN: 1432-0878
    Keywords: Pituicytes ; Anuran ; Innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pituicytes of Rana pipiens could be classified into two types, pale and dense, according to their relative densities of cytoplasm and the populations of free ribosomes and cell organelles. An intermediate type of pituicyte was also recognized. Lipid droplet such as are typical in the cytoplasm of mammalian pituicytes, are not in the cytoplasm of either types of frog pituicyte. Both types have long cytoplasmic processes which run among the nerve fibers, and some of them end at the pericapillary space. Nerve endings making synapse-like contacts with the cell bodies or the processes of the pituicyte are frequent. According to the structures and sizes of granules and vesicles in the nerve endings, these endings are classified into one of three types: 1) A, which appears to be a peptidergic neuronal ending containing dense granules 1,200–2,000 Å in diameter and small clear vesicles 300–400 Å in diameter; 2) B, which appear to be monoaminergic endings containing cored vesicles 600–1,000 Å in diameter and small clear vesicles 300–500 Å in diameter; 3) C, which appear to be cholinergic endings containing only small clear vesicles. Type C endings are relatively rare. In the synaptic area the axonal membranes appose those of the pituicytes across a gap of about 200 Å and numerous “presynaptic” vesicles are clustered or accumulated near the presynaptic membranes.
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  • 13
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    Cell & tissue research 111 (1970), S. 572-585 
    ISSN: 1432-0878
    Keywords: Brain ; Intraventricular cellular processes ; Ependyma ; Lateral ventricle ; Synapses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Ependym und subependymale Strukturen der Seitenventrikel von Katzen aus dem Bereich des Nucleus caudatus und des Corpus callosum wurden nach Perfusionsfixierung elektronenmikroskopisch untersucht. Dort findet sich eine Reihe von Neuritenanschnitten, deren kolbenförmige Auftreibungen leere Vesikel, “dense core granula” und Mitochondrien enthalten. Neben diesen neuronalen Elementen werden auch Zellfortsätze nichtneuronaler Natur im Ventrikellumen beobachtet, die Ependym- und intraventrikulären Zellen entstammen. An umschriebenen Stellen nehmen diese kolbig aufgetriebenen Fortsätze desmosomenartige Kontakte mit dem Ependym auf. An diesen Orten umgeben Mikrovilli die Fortsätze korbartig. Ob es sich bei diesen Kontakten um synapsenartige Strukturen handelt, oder um „Rezeptoren“ für unbekannte chemische Stoffe, wird diskutiert. Die Kontakte sind unabhängig von der Form der Ependymzellen und davon, ob diesen graue oder weiße Substanz unterliegt. Zwischen und in den Ependymzellen finden sich — bedingt durch den unterschiedlichen Gehalt an Zellorganellen — drei verschiedene Arten von Fortsätzen. Die Zahl der neuronalen Fortsätze in diesem Bereich ist sehr viel kleiner als im Ventrikellumen.
    Notes: Summary Ependyma and subependymal regions of the lateral ventricles of cats (area of Nucleus caudatus and Corpus callosum) were fixed by perfusion and investigated electronmicroscopically. Intraventricular axons showing a beaded shape with smaller and thicker parts were found. The varicosities contain empty vesicles, dense core granules and mitochondria. Beside those certainly neuronal elements there exist intraventricular cell processes originating from ependymal cells and free cells. The neuronal processes make desmosome-like contacts with the ependyma. These regions of contact are surrounded by basket-like arranged microvilli. It is discussed, whether the contacts function like synapses or as receptors for a substance, which is still unknown. Contacts do not depend on the shape of ependymal cells. They exist with the ependyma of Nucleus caudatus (grey substance) as well as with the ependyma of Corpus callosum (white substance). Because of the different contents of cell-organelles one can differentiate three different sorts of processes situated inter- or intracellularly in the ependyma. Neuronal processes within the lateral ventricles are more numerous than those found within the ependymal layer.
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  • 14
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    Cell & tissue research 111 (1970), S. 179-194 
    ISSN: 1432-0878
    Keywords: Synaptosomes ; Rat cerebral cortex ; Synapses ; Postnatal development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Synaptosomes (nerve-ending particles) prepared from the cerebral cortex of rats, aged 2–21 days, were examined after fixation in glutaraldehyde and osmium tetroxide, in order to study the development of the contact region between their pre- and postsynaptic components. Synaptosomes were present at all ages studied, although they increased in number and underwent morphological changes, e.g. a decrease in ribosomes and increase in synaptic vesicles, during development. The seventh postnatal day appeared to be a critical period for development, as many adult features were first observed at this time. The synaptic contact region was characterized by desmosome-like symmetrical thickenings until the fourth postnatal day, after which it became increasingly asymmetrical. The postsynaptic thickening, which had been undifferentiated until the seventh day, underwent a focalization of its material at this stage to form postsynaptic densities typical of the adult synapse. Cleft material was present at all ages, although for the first few days it was sparse and comparatively unorganized. An attempt has been made to distinguish between synaptosomes derived from axosomatic and axodendritic endings. The possible significance of the early desmosome-like thickenings is discussed, and the role of the cleft material and post-synaptic densities in the development of the synapse is analysed.
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  • 15
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    Cell & tissue research 114 (1971), S. 135-150 
    ISSN: 1432-0878
    Keywords: Pars tuberalis ; Rana temporaria ; Structure and ultrastructure ; Vascularization ; Innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pars tuberalis of the hypophysis of Rana temporaria presents the general structural and the cytological characteristics of an endocrine gland. It is composed of elongated cells with long, branching processes ending on the external basement membrane of the pericapillary space. The pars tuberalis cells produce secretory granules which are accumulated in the pericapillary endings of the processes. Corresponding to its separate localization, the pars tuberalis of Rana temporaria has a separate vascularization of which the efferent capillaries anastomose with the capillary plexus of the median eminence. The general direction of the blood flow of the pars tuberalis is towards the capillaries of the median eminence. Also, the secretory products of the pars tuberalis pass into the blood stream of the hypophysial portal system. Several characteristics of the pars tuberalis show that its function must be different from that of the pars distalis of the hypophysis. Moreover, in contrast with the pars distalis, the activity of the pars tuberalis is not regulated by neurohumoral factors. The results show that a role of the pars tuberalis in the regulation of the activity of the pars distalis of the hypophysis is not excluded.
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  • 16
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    Cell & tissue research 115 (1971), S. 494-500 
    ISSN: 1432-0878
    Keywords: Axon ; Synapses ; Astrocytes ; Thalamus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopic studies and three-dimensional graphic reconstructions from serial sections have shown that the large axon terminals of synaptic glomeruli in the ventrobasal nucleus of the rat are invaginated by spine-like protrusions from the astrocyte processes surrounding the glomeruli (“micro-trophospongium”). The astrocytic protrusions are similar in dimensions and internal morphology to the synapse-bearing dendritic excrescences that also invaginate the large axon terminals. Consequently astrocytic protrusions may be overlooked, or confused with dendritic excrescences sectioned at a non-synaptic level. The intimate neuronal—neuroglial relationship at such large axon terminals may reflect ion-exchange or metabolic interactions between the astrocytes and the axon terminal.
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  • 17
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    Cell & tissue research 116 (1971), S. 151-156 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Innervation ; Receptors ; Rat ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the adrenal cortex of the rat and the pig is investigated with the electron microscope. Nerve fibers containing synaptic and two types of dense-cored vesicles come into contact with endocrine cells. There are no specialized pre- and postsynaptic membranes. The synaptic cleft is about 200 Å wide. Generally the basement membrane between nerve and cell is absent. These observations are discussed on the base of more recent experimental findings. Small fibers having an average diameter of about 0.2 to 0.5 μ and containing only tubules and filaments are considered to represent parts of an afferent nervous system.
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  • 18
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    Cell & tissue research 118 (1971), S. 1-11 
    ISSN: 1432-0878
    Keywords: Fetal microvasculature ; Innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the mesenteric microvasculature was studied in fetal and neonatal rabbits with the aid of methods demonstrating fluorescence of catecholamines and cholinesterase activity as well as a silver impregnation procedure. The results showed that: (1) adrenergic nerve fibers were present, coursing independently in the mesentery by day twenty-one of gestation, and were found routinely in the adventitia of arterioles and venules by day 25 of gestation; (2) cholinesterase positive cells and fibers of the myenteric plexus were present by day 18 of gestation but cholinergic fibers were not present in the mesentery until day 26; the latter not being associated with blood vessels; and (3) nerve fibers in the mesentery thought to be sensory stained positively with the Holmes silver method on day 18 of gestation.
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  • 19
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    Cell & tissue research 119 (1971), S. 99-114 
    ISSN: 1432-0878
    Keywords: Peripheral nerve ; Body size ; Axon diameter/Fibre diameter ; Internodal length ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Nn. ischiadici von Maus, Ratte, Meerschweinchen, Hund und Katze wurden licht- und elektronenmikroskopisch faseranalytisch untersucht (Methodik s. G. Schnepp u.a., 1971). Dem Vergleich diente der N. phrenicus des Hundes. 1. Für den Quotienten „g” (=mittlerer Axondurchmesser/Fasergesamtdurchmesser) ergibt sich am lichtmikroskopischen Material ein stetiger Anstieg von 0,4 für dünne Fasern bis zu 0,6 für die dicksten Fasern. Bei gleichem Gesamtdurchmesser haben Ratten und Hunde die stärksten, Mäuse dagegen die dünnsten Markscheiden. 2. Die elektronenmikroskopisch ermittelten Werte des Quotienten „g” weichen von den lichtmikroskopischen ab. Bei den ersteren ergibt sich eine weitgehende Konstanz um 0,6. Diese Werte entsprechen den von Rushton (1951) aus theoretischen Gründen geforderten. Auch im elektronenmikroskopischen Material haben die Nervenfasern der Ratte die stärksten Markscheiden. 3. Eine lineare Proportionalität zwischen der Internodallänge einer Tierart und dem steigenden Faserdurchmesser wird bestätigt. In jedem N. ischiadicus kommen vereinzelte Fasern mit Internodalabständen von etwa 300 μ vor, unabhängig vom Faserkaliber. 4. Im elektronenmikroskopischen Bild sind keine artspezifischen Unterschiede in der Struktur und Verteilung der marklosen Nervenfasern zu beobachten.
    Notes: Summary The sciatic nerves were analysed using light and electron microscopes in the mouse, rat, guinea pig, cat, and dog (see Methods of G. Schnepp et al., 1971). 1. In light microscopic material, the ratio “g” between mean axon diameter and mean fibre diameter increased from 0.4 for small fibres to 0.6 for the thick fibres. For a given fibre diameter the myelin sheaths in rats and dogs were the thickest, while those in mice were the thinnest. 2. The ratio “g” in electron micrographs on the other hand was constant at 0.6 over a wide range of fibre diameters. The ultrastructural values agreed with those postulated by Rushton (1951) for optimal nerve conduction. In the electron microscopic material, the myelin sheaths were the thickest in the rat. 3. A linear proportionality was confirmed to exist between internodal length and increasing fibre size. Independently of fibre size, in all sciatic nerves, a few fibres were found with internodal length of about 300 μ. 4. In electron micrographs, no species differences were observed in the structure or distribution of unmyelinated nerve fibres.
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  • 20
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    Cell & tissue research 119 (1971), S. 115-119 
    ISSN: 1432-0878
    Keywords: Human thymus ; Innervation ; Quantitative electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Quantitative electron microscopic studies have been carried out on the human thymus. According to the equation L v =(2n)/F (Hennig, 1963) we have calculated that there is less than 0.204 mm nerve per 1 mm3 thymus tissue inside the blood-thymus-barrier (level of significance of 0.95). This result is compared to the degree of innervation in brown adipose tissue, which contains more than 160 mm nerve per 1 mm3 tissue. The biological significance of the paucity of neuronal elements in the thymus is undetermined.
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  • 21
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    Cell & tissue research 119 (1971), S. 326-333 
    ISSN: 1432-0878
    Keywords: Median eminence ; Frog ; Serotoninergic nerve fibers ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary For the identification of the nerve fiber containing serotonin (5-hydroxytryptamine) in the frog median eminence, an electron microscopic autoradiography was performed with 5-hydroxytryptophane-3H which is the precursor of serotonin. At 1 and 24 hours after the intraperitoneal injection, most silver grains were located over the nerve fibers and endings, and a few were also found over the glia cell and the perivascular space. A large number of silver grains were located over the type 3 nerve endings (Nakai, 1971) containing small dense granules about 600–1000 Å in diameter 1 and 24 hours after the injection. Some silver grains were localized over the nerve endings containing intermediate-size dense granules 1100–1700 Å in diameter. Silver grains were also frequently observed over the nerve fibers in the inner layer of frog median eminence. There is no significant difference in the pattern of distribution of silver grains between tissues of 1 hour and 24 hours after the injection.
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  • 22
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    Cell & tissue research 119 (1971), S. 384-404 
    ISSN: 1432-0878
    Keywords: Glandula harderiana ; Rabbit ; Extrusion mechanism ; Lipid vacuoles ; Innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung 1. Die Glandula harderiana des Kaninchens ist eine tubulo-alveoläre Drüse. Sie liegt an der medialen und hinteren Wand der Orbita und besteht aus zwei, makroskopisch unterscheidbaren Anteilen: Ein kleinerer oberer Teil ist von weißer Farbe, der größere untere ist rot. Die sezernierenden Zellen in den tubulösen Endstücken beider Lappen enthalten Fette, die sich mit Scharlachrot und Sudanschwarz B anfärben. Die luminale Oberfläche aller Zelltypen färbt sich mit Alcianblau bei pH 2,5 an. 2. Die Drüsentubuli beider Lappen sind von einem einschichtigen kubischen bis zylindrischen Epithel ausgekleidet. Die Drüsenzellen sind im roten Anteil großblasig, im weißen Lappen sehr fein vakuolisiert. Das Cytoplasma dieser multiloculären Zellen enthält freie Ribosomen und eine erstaunlich große Zahl von Mitochondrien, die meistens eng aneinander lagern. Alle Zellen enthalten ferner mehrere Golgi-Stapel, aber nur spärliche Ergastoplasmamembranen. 3. Die exokrinen Zellen werden an den seitlichen Kontaktflächen durch ein differenziertes Schlußleistennetz (Zonulae occludentes, Zonulae adhaerentes, Desmosomen) verbunden. Die sezernierende Oberfläche wird durch die Ausbildung interzellulärer Sekretkapillaren vergrößert. 4. Bevor die Fettsubstanzen in die Lichtungen der Drüsenschläuche extrudiert werden, kommt es zur Verschmelzung benachbart liegender Pettvakuolen. Die Extrusion wird abgeschlossen durch das Verschmelzen der Hüllmembran der Fettvakuolen mit der Plasmamembran, durch Ausbildung einer Öffnung in der Plasmamembran und durch das Ausfließen der Fettsubstanzen. Ein anderer Extrusionsmechanismus besteht darin, daß apikal gelegene Fettvakuolen die Zellmembran weit in die Lichtung hinein vorwölben und anschließend mit einer Hüllmembran abgenabelt werden. 5. Terminale Nervenfasern mit bekannter Innenstruktur durchbrechen die Basalmembran und lagern sich den Drüsen- oder Myoepithelzellen eng an, teilweise in Vertiefungen ihrer Oberfläche eingebettet. Diese terminalen Axone enthalten synaptische Vesikel, Bläschen mit einem massendichten Granulum, Mitochondrien und Neurotubuli. Spezialisierte prä- und postsynaptische Membranen kommen nicht vor. Die Frage nach der funktionellen Bedeutung der Harderschen Drüse wird diskutiert.
    Notes: Summary 1. The Harderian gland in rabbits, representing the type of a tubulo-alveolar gland, is located on the medial and posterior aspect of the eyeball and consists of two different parts, a small white lobe and a larger red one. The secretory cells in the tubular endpieces of both lobes are lipids containing cells. The lipid droplets can be stained with Sudan IV and Sudan black B. The luminal surface of both cell types is characterized by an alcianophilia at pH 2,5. 2. The tubules of both lobes have a single layer of columnar epithelium. The lipid vacuoles in the cells of the red lobe are large, these of the white lobe small. The multilocular cytoplasm of all cells contains many free ribosomes and high amounts of mitochondria lying very closely together. All cells exhibit numerous and large Golgi-zones but only few ergastoplasm membranes. 3. The lateral surfaces of the secretory cells are connected by elaborate junctional complexes (Zonulae occludentes, zonulae adhaerentes, desmosomes). These lateral surfaces are increased by intercellular canaliculi. 4. Before being released into the glandular lumen, the limiting membranes of adjacent lipid droplets fuse, thus forming a large lipid vacuole. Extrusion generally is characterized by the coalescence of the limiting membrane with the plasmalemma, the formation of an opening at the cell surface and the discharge of the secretory lipid material. In the course of another mechanism of extrusion, the fat vacuoles are transported to the apical part of the cell where consequently the plasmamembrane bulges into the lumen. Eventually the fat vacuole is pinched off surrounded by a thin cytoplasmic envelope. 5. Terminal fibers of the autonomic nervous system penetrate the basal membrane and can be found closely attached to the secretory or myoepithelial cells, partly by forming large swellings, which may be deeply embedded into the cytoplasm of the innervated cell. These terminal parts of the axons contain groups of synaptic and dense-cored vesicles, mitochondria and neurotubuli. Specific pre- and postsynaptic membranes have not been observed. The possible function of the harderian gland is discussed.
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  • 23
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    Cell & tissue research 121 (1971), S. 283-291 
    ISSN: 1432-0878
    Keywords: Anterior pituitary ; Parathyroids ; Innervation ; Quantitative electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopic studies have been carried out on the innervation of the mammalian anterior pituitary and parathyroids. The total area of grid squares (2.25·10−2mm2) examined was 2000 per gland and species. In the pituitary pars distalis and in the parenchyma of the parathyroid gland we did not observe a single axon profile. According to the equation $$L_V = \frac{{2n}}{F}$$ proposed by Hennig (1963) we have calculated that there might be—if any—0.133 mm of nerves per 1 mm3 tissue in those two endocrine glands (level of significance 0.95). Comparing these results to the degree of innervation in brown adipose tissue containing more than 160 mm nerve per 1 mm3 tissue we can not imagine that such a small degree of innervation is of any biological importance. In the pituitary pars tuberalis two types of axon terminals have been found both inside and outside the basement membrane surrounding the epithelial complexes. One type contains “synaptic” and two populations of smaller dense-cored vesicles, the other one contains a population of larger granules which have some properties of the classical elementary granules. Further investigations have to clarify the functional significance of those nerve endings.
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  • 24
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    Cell & tissue research 127 (1972), S. 240-257 
    ISSN: 1432-0878
    Keywords: Insects ; Brain ; Corpora pedunculata ; α-lobe ; Synapses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Organisation der α-Loben der Pilzkörper im Gehirn von Acheta domesticus L. wird nach licht- und elektronenmikroskopischen Befunden beschrieben. Der säulenartige Faserkomplex des α-Lobus besteht aus Fortsätzen von Pilzkörperzellfasern (intrinsischen Fasern, IF) und pilzkörperfremden Fasern (extrinsischen Fasern, EF), die in den Lobus eindringen. Die feinen IF durchziehen den Lobus hauptsächlich parallel zu seiner Längsachse, während die EF zumeist senkrecht zur Längsachse angeordnet sind. Der Lobus erscheint von seiner Peripherie bis zu seinem Zentrum durch IF-Zonen gegliedert. Die Verteilung der EF weist auf eine zusätzliche Ordnung von der Basis zur Spitze des Lobus hin. Zahlreiche polarisierte Synapsen verbinden IF mit EF. Die IF zeigen Vesikelanhäufungen und präsynaptische Apparate besonders in Erweiterungen, die auch in Golgi-Präparaten lichtmikroskopisch zu sehen sind. Es werden zwei EF-Typen unterschieden: 1. Postsynaptische EF (zahlreich) und 2. EF mit prä- und postsynaptischen Kontakten, die nur in einigen Regionen des α-Lobus gefunden wurden. Präsynaptische IF konvergieren auf „dendritische“ EF, die Verbindungen mit anderen Teilen des Hirns und des Nervensystems herstellen. Funktionelle Gesichtspunkte werden diskutiert.
    Notes: Summary The organization of the α-lobes of the corpora pedunculata in the brain of the cricket Acheta domesticus L. has been investigated in the light and electron microscopes. The cylindrical fibre complex is composed of branches of “mushroom-body” fibres (intrinsic fibres) and extrinsic fibres, which penetrate the α-lobe. Intrinsic fibres (IF) run through the α-lobe in the same direction, but not strictly parallel to each other or to the axis of the α-lobe. Extrinsic fibres (EF) and their fine branches are often arranged perpendicular to the axis of the α-lobe. There is some evidence that different IF zones occur in the α-lobe when passing from its periphery to its centre. The distribution of EF may reflect a structural order when passing from the base of the lobe to its top. Numerous polarized synapses connect the IF with the EF. The IF show clusters of vesicles and presynaptic figures especially in their “blebs”, which can be seen in Golgi preparations for light microscopy. Two types of EF are distinguished on the basis of their synaptic junctions: (1) postsynaptic EF (abundant) and (2) EF with pre- and postsynaptic sites (perhaps restricted to some regions of the α-lobe). Presynaptic IF converge on EF, which may transfer excitation from the α-lobe to different parts of the brain and nervous system.
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  • 25
    ISSN: 1432-0878
    Keywords: Synapses ; Crustacea ; Abdominal Ganglia ; Lateral glant fibers ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The abdominal ganglia of the crayfish Astacus pallipes contain numerous vertebrate-like synapses which are characterized by presynaptic vesicles, darkened pre- and post-synaptic membranes, cleft material, and post-synaptic “fuzz”. Such synapses occur throughout the ganglia but are most easily found dorsally, where the neuropile is relatively coarse. The neuropile is far from homogeneous. Regional variations in fiber size, in degree of profile tortuosity, and in kind, magnitude, and distribution of vesicular content result in conspicuous textural variations. The structural polarity of synapses between the lateral giant fibers and other neurons is consistent with known physiological polarity and, hence, validates our criteria for recognition of synapses within the ganglion.
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  • 26
    ISSN: 1432-0878
    Keywords: Penis retractor muscle ; Helix pomatia ; Innervation ; Neuromuscular junctions ; Synaptic vesicles ; Neurotransmitter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Der Penisretraktormuskel von Helix pomatia wird von dicken Nervenstämmen durchzogen, die wahrscheinlich Nervennetze darstellen. Im kontrahierten Muskel sind sie mäanderförmig aufgefaltet, im gedehnten glattgezogen. Vier verschiedene Vesikeltypen lassen sich nach Größe und Inhalt in den Nerven unterscheiden. Varicöse Einzelfasern begleiten die Muskelzellen. Häufig verlaufen die Terminalen in einer Furche der Muskelfaser. Praesynaptisch erkennt man bei bestimmten Axontypen Vesikelanhäufungen und Verdickungen der Terminalenmembran. Terminale und Muskelzelle sind durch einen Spalt von 300 AE Breite voneinander getrennt. Die Muskelfasermembran bildet keine subsynaptischen Falten aus. Neben diesen Axonen durchziehen dünne, nackte Neuriten das Bindegewebe, die durch einen hohen Gehalt an Neurotubuli ausgezeichnet sind.
    Notes: Summary The penis retractor muscle of Helix pomatia is passed by thick nerve trunks, which probably are nerve nets. In the contracted muscle, they are folded meanderlike, in the extended they are pulled smooth. Four types of vesicles different in size and contents can be distinguished in the nerves. Varicose fibres accompany the muscle cells. Frequently the terminals are running in a groove of the muscle fibre. In certain axon types occur presynaptic accumulations of vesicles and thickenings of the terminal membrane. Terminal and muscle cell are separated by a cleft of 300 AE width. The muscle fibre membrane has no subsynaptic infoldings. Beside these axons thin, naked neurites are running through the connective tissue. They are characterized by a high content of neurotubuli. One part of the axons presumably possesses a monoaminergic transmitter. After the glutaraldehyde-dichromate-reaction they contain dense grana, whose diameters are mainly below 1000 AE. The nerve trunks fluoresce after exposure to paraformaldehyde vapour, excited with UV-light, green to green-yellow. The maximum of the excitation was determined at 413 nm and the maximum of emission at 496 respectively at 510 nm. It is concluded, that both, a catecholamine and 5-HT are responsible for the fluorescence. Extraction and paperchromatographic separation lead to the opinion, that the catecholamine is dopamine.
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  • 27
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    Cell & tissue research 131 (1972), S. 329-346 
    ISSN: 1432-0878
    Keywords: Olfactory mucosa ; Mouse ; Glands of Bowman ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Das erste Auftreten der Glandulae olfactoriae in der olfaktorischen Region der Maus wird beschrieben. Die Struktur der Bowmanschen Drüse und ihre topologische Beziehung zu den übrigen zellulären Elementen im Riechepithel wird untersucht. Die Bedeutung des Sekrets für die Bildung des Deckhäutchens wird diskutiert. Die Bowmanschen Drüsen der Maus erreichen im letzten Viertel des intrauterinen Lebens die Lamina propria des Riechepithels. In den Endstücken finden sich dunkle, sekretreiche und helle, sekretarme Zellen. Die sezernierenden Zellen der Bowmanschen Drüsen sind nicht auf die Lamina propria beschränkt, sondern erstrecken sich bis in die untersten Anteile des Kernlagers im Riechepithel. Beim Austritt der Bowmanschen Drüsen aus dem Riechepithel in die Lamina propria konfluieren die Basalmembranen dieser Gewebeanteile miteinander. Die gemeinsame Basalmembran kann sich noch eine Strecke weit bis in den normalen Interzellularraum zwischen Drüsen- und Riechepithelanteilen einsenken. In den apikalen Anteilen des Riechepithels wird der Ausführungsgang von den benachbarten Sinnes- und Stützzellen nur durch eine normal breite Interzellularfuge getrennt. Im Ausführungsgang der Bowmanschen Drüse finden sich dunkle und helle auskleidende Zellen. Die durch Desmosomen miteinander verbundenen Epithelzellen der Ausführungsgänge zeigen Zeichen einer Sekretion. Die periphersten Ausläufer des Ausführungsgangepithels erstrecken sich lediglich bis in das Terminalplattenniveau der Stützzellen, mit denen sie sich durch desmosomenartige Kontaktzonen verbinden. In der Verlängerung der Ausführungsgänge wird das Lumen peripher des Terminalplattenniveaus von den apikalen Stützzellanteilen und deren Mikrovilli sowie von den obersten Anteilen der Dendriten, von den Riechköpfen und den Sinneshaaren der Rezeptorzellen umgrenzt. Im Lumen der Ausführungsgangverlängerung finden sich im Bereich des olfaktorischen Saumes flächenhafte Ansammlungen von Sekret. Das Sekret im intervillösen Raum des olfaktorischen Saumes zeigt eine besondere Affinität zu den Membranen der peripheren Sinneszellausläufer. In der intrauterinen Lebensphase ließ sich bisher kein Deckhäutchen feststellen. Die austrocknende Wirkung der Luft auf das Sekret der Bowmanschen Drüsen wird als Entstehungsmechanismus für das Deckhäutchen in Erwägung gezogen.
    Notes: Summary First appearance, structure and topological relations of Bowmans' glands in the regio olfactoria of white mice are described. The importance of these glands for the formation of the terminal mucous cover of the olfactory epithelium is discussed. In the last quarter of intrauterine life the glands of Bowman reach the lamina propria. In the terminal portion of the glands dark cells with many secretory droplets and pale cells with only a few of them can be seen. Secretory active cells are localized in the basal part of the olfactory epithelium as well. When entering the lamina propria the irregular wide basement membrane of the glands joins that one of the epithelium. It is possible to follow up this joined basement membrane for a short distance between the glands and the cells of the olfactory epithelium. Peripheral to the very basal part of the olfactory epithelium there is no basement membrane around the glands' tissue. Receptors and sustentacular cells are separated from the gland only by a normal intercellular space. The epithelium of the ducts consists of dark and light cells as well. They are connected with the sustentacular cells by desmosomelike contacts. In its prolongation the lumen of Bowman's duct is lined by the apical portions of the sustentacular cells and their microvilli, and by dendrites, olfactory vesicles, and sensory cilia of the receptor cells. In the region of cilia and microvilli one can see masses of secretion which have confluenced. In the intervillous space its special affinity to the receptor's membranes is evident. During the intrauterine phase of life no terminal mucous cover could be demonstrated. The drying effect of the air as a possible reason for the origin of the terminal mucous cover is discussed.
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  • 28
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    Cell & tissue research 131 (1972), S. 287-297 
    ISSN: 1432-0878
    Keywords: Histocytochemistry ; Autoradiography ; Blood vessels ; Lymph nodes ; Intestine, small
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The histochemistry and DNA turnover of postcapillary high-endothelial venules in lymph nodes and Peyer's patches have been investigated. Autoradiographic studies showed that the cells are long lived. They exhibit a distinct metachromatic reaction that is indicative of a moderate amount of RNA. They are PAS positive due to the presence of glycogen. Considerable amounts of mucopolysaccharides are not found inside the cells. The reactions for lactate dehydrogenase, NADH-tetrazolium reductase and unspecific esterase are strong. The intensities of the reactions are comparable to those of the epithelium of the intestinal villus and of reticular cells and definitely stronger than that of other endothelial cells. Tests for acid phosphatase, alkaline phosphatase, succinic dehydrogenase, glucose-6-phosphate dehydrogenase and NADPH-tetrazolium reductase showed that these enzymes are either absent or present in small amounts.
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  • 29
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    Cell & tissue research 132 (1972), S. 245-256 
    ISSN: 1432-0878
    Keywords: Olfactory organs (Fish)-Labyrinth Cells ; Ion transport ; Evolution ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Light microscopy and transverse electron microscopy has been employed to study the olfactory organs in 82 specimens of freshwater adapted young and homing adult Baltic sea trout Salmo trutta trutta L. In both sensory and indifferent epithelium the olfactory mucosa has scattered cells of a type that has not been described in any olfactory organ before. They are called labyrinth cells and are characterized by an extensive, turtuous, interconnected tubular system of smooth endoplasmatic reticulum intimately connected with numerous mitochondria. This cell type is similar to chloride and other cells which probably are involved in electrolyte transport in fish gills and pseudobranch, the rectal gland in elasmobranchs and the nasal gland in reptiles and birds. It is suggested that the olfactory organ in fish is serially homologous with the pseudobranch.
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  • 30
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    Cell & tissue research 135 (1972), S. 1-26 
    ISSN: 1432-0878
    Keywords: Retina ; Hypothalamus (Mammals) ; Suprachiasmatic nucleus ; Neuroendocrinology ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Retino-hypothalamic connections have been studied autoradiographically in the rat, guinea pig, rabbit, cat and monkey following the intravitreal injection of 3H-leucine or 3H-proline, and electron microscopically following unilateral eye removal in the guinea pig and monkey. In each of the species examined evidence has been found for a direct projection from the retina to the suprachiasmatic nucleus, but to no other region of the hypothalamus. The projection to the suprachiasmatic nucleus is always bilateral (even in the albino guinea pig, in which all other components of the retinal projection are crossed) but from grain counts in our autoradiographs it appears that the input to the contralateral nucleus is about twice as heavy as that on the ipsilateral side. Most of the retinal fibers appear to terminate within the ventral part of the nucleus where they form asymmetric synapses either upon small dendritic branches or dendritic spines. The possible role of this retinal projection to the suprachiasmatic nucleus in mediating a variety of light-induced neuroendocrine responses is discussed.
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  • 31
    ISSN: 1432-0878
    Keywords: Subcommissural organ ; Reissner's fibre ; Rana esculenta ; Light/Darkness ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The influence of long daily photoperiods and of continuous darkness on the secretory activity of the subcommissural organ (SCO) and on the growth rate of Reissner's fibre (RF) in Rana esculenta was studied in winter. The amount of aldehyde-fuchsin (AF) positive material in the apical cell parts of the SCO is smaller in light-adapted than in darkness-adapted animals. Differences in incorporation rate of 35S-cysteine between the SCO of light-adapted and of darkness-adapted animals, however, are small. The conclusion must be that light/darkness conditions only slightly influence the secretory activity of the SCO cells of Rana esculenta. In agreement with this conclusion is the observation that RF grew only slightly faster in the light-adapted than in the darkness-adapted animals. Under the conditions used RF was completely renewed in about 3 to 4 days. Influences of temperature on the activity of the SCO have been observed.
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  • 32
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    Cell & tissue research 139 (1973), S. 179-200 
    ISSN: 1432-0878
    Keywords: Retino-preoptic pathway ; Optic tracts ; Rana temporaria ; Light microscopy ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The optic tracts and centres of optic terminals of Rana temporaria have been investigated with silver impregnation techniques after unilaterally cutting the optic nerve and autoradiographically after injection of a mixture of tritiated amino acids into the vitreous body of the left eye. The observations on the course of the optic tracts and on the optic terminals in the thalamus and optic tectum are to a great extent in agreement with those of other authors. The probability of a retino-preoptic pathway is supported by the detection of fibres running in dorsal direction in front of the place where the optic nerve penetrates the brain. In horizontal sections these fibres can be seen deviating from the optic tract, covering a short distance in frontal direction and then turning upward under an angle of about 90 degrees. They disappear between the ventral aldehyde-fuchsin positive cells of the preoptic nucleus. The ventral and median parts of the ipsilateral preoptic nucleus contain fragments of degenerated fibres. Autoradiographic data are also in favour of the presence of an ipsilateral retino-preoptic tract. After carefully counting the number of grains over left and right preoptic nucleus, it appeared that over the ventral and median parts of the left preoptic nucleus more grains occur than over the identical areas of the right one.
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  • 33
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    Cell & tissue research 136 (1973), S. 355-364 
    ISSN: 1432-0878
    Keywords: Hypothalamo-hypophysial system ; Rana temporaria ; Blinding ; Illumination ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The influence of a long daily photoperiod and continuous darkness on the hypothalamo-hypophysial system of blinded frogs was studied. In the preoptic nucleus no difference could be observed between the two groups of blinded frogs neither in the amount of incorporated 35S-cysteine nor in the amount of aldehydefuchsin positive material nor in the nuclear volume of the secretory cells. These results were compared with those of an experiment with intact frogs kept simultaneously under the same environmental conditions. It appeared that the activity of the dark-treated blinded group was enhanced compared with the activity of the dark-treated intact group while the light-treated blinded frogs showed a decrease in activity compared with the similarly treated intact animals. Likewise the influence of a long daily photoperiod on the hypothalamo-hypophysial system of unilaterally blinded frogs was studied. The activity of the preoptic nucleus was lower on the side where the optic nerve had been cut than on the intact side. In the dorsal part of the preoptic nucleus a difference between the two sides could not be observed. The significance of these results is discussed with regards to a possible connection between retina and preoptic nucleus.
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  • 34
    ISSN: 1432-0878
    Keywords: Skin ; Anurans ; Regional differences in grafts ; Neuroepithelial relationships ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Recent investigations have suggested specific differences in back and belly skin in anurans which appear to influence the quality of reflex responses obtained from various areas of the animals body. The present investigation represents a comparative morphological study of back and belly skin in control and skin-graftedRana pipiens, with special regard to the neuroepithelial relationships. A distinct difference in pigmentation of back and belly skin was observed. Intra-epithelial Merkel cells were present in all skin samples studied. The origins of the numerous unclassifiable cells in the Merkel cell region are discussed in relation to a presumed coordinating function of the Merkel cell during epithelial differentiation. Epitheliomesenchymal interactions were observed in the richly innvervated dermal regions. Two types of morphologically different intra-epithelial nerve endings were observed. These observations are discussed in relation to earlier observations on vertebrate skin and in relation to misdirected reflex responses obtained in skin-grafted anurans.
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  • 35
    ISSN: 1432-0878
    Keywords: Neurosecretion ; Annelida ; Sexuality and Development ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Während der sexuellen Entwicklung vonPlatynereis dumerilii steigt die Zahl der Neurone, die Merkmale einer sekretorischen Aktivität aufweisen, parallel zum Wachstum und zur Reifung der Keimzelle an. Die cytologische Differenzierung eines Neurons zur neurosekretorischen Zelle ist mit einer Steigerung der Synthese Cystin-haltigen Materials gegenüber konventionellen Neuronen gekoppelt. Neurosekretorische Zellen treten erstmals in Erscheinung, kurz bevor die Oocyten in die zweite Oogeniephase eintreten, während der die Vitellogenese abläuft. Aufgetragen gegen den Oocytendurchmesser ergibt die Zahl der Neurone, die sekretorisch aktiv werden und3H-Cystin inkorporieren, eine ansteigende Kurve. Die Kurve biegt auf ein Plateau, wenn die Oocyten eine kritische Größe erreichen. Diese Größe markiert jenes Entwicklungsstadium, von dem ab eine Enthirnung eine normale Reifung nicht mehr verhindert. Die Zahl synthetisch tätiger Neurone steight erneut an, wenn die Oocyten die kortikale Struktur des reifen Eies entwickeln. Das Maximum wird kurz vor der Metamorphose erreicht. Während der epitoken Umwandlung sinkt die synthetische Aktivität rasch ab, um im schwärmbereiten Tier gänzlich zum Stillstand zu kommen. In Tieren, die nach der kritischen Phase zur caudalen Regeneration veranlaßt werden, fällt die Zahl markierter neurosekretorischer Zellen auf ein Niveau ab, das für junge, „vorkritische“ Individuen charakteristisch ist. Entsprechend wird in jungen, vorkritischen Tieren, die erst wenige endokrine Neurone besitzen, die Differenzierung weiterer neurosekretorischer Zellen durch eine Regeneration nicht stimuliert. Der zeitliche Verlauf der synthetischen Aktivität im Zuge der Entwicklung und die durch eine Regeneration erzwungenen Veränderungen sind somit reziprok zur Aktivität des Gehirns in Bezug auf die Ausschüttung des Juvenilhormons. Die Hypothese wird zur Diskussion gestellt, die sinkende Produktion des Juvenilhormons werde von der steigenden Produktion eines antagonistischen neuroendokrinen Prinzips begleitet oder verursacht.
    Notes: Summary During sexual development ofPlatynereis dumerilii, the number of neurones exhibiting secretory activity rises in parallel with the growth and maturation of the germ cells. The cytological differentiation of neuroglandular properties is accompanied with an increased uptake of tritiated cystine. The first neurones developing the characteristics of secretory cells and incorporating cystine appear just before the oocytes enter the second growth phase which corresponds with vitellogenesis. When plotted against the oocyte diameter the number of labelled neurosecretory cells yields an ascending line, which becomes a plateau once the oocytes approach a critical size. This critical size defines the developmental stage beyond which decerebration does not prevent normal maturation. The neuronal synthetic activity rises again when the oocytes differentiate the cortical structure of ripe eggs. The curve displays its maximum slope at the onset of metamorphosis. During the epitokous transformation the synthetic activity decreases rapidly and is almost totally depressed when swarming is imminent. In animals induced to regenerate their posterior segments after they have passed the critical stage, the number of labelled neurosecretory cells becomes reduced to the precritical level. According to this, regeneration in young precritical animals containing only few endocrine neurones does not stimulate the development of further secretory neurones. Thus, the time course during maturation and the changes caused by regeneration are reciprocal to the activity of the brain with respect to the release of juvenile hormone. The question is thus raised as to whether the declining titer of juvenile hormone may be accompanied or caused by an increased production of an antagonistic principle related to maturation.
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  • 36
    ISSN: 1432-0878
    Keywords: Pigment cells ; Pterinosomes ; Skin ; Rana japonica ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Structural changes in drosopterinosomes (red pigment granules) of Rana japonica in the process of erythrophore differentiation were studied by light and electron microscopy. On the basis of the degree of pterinosome differentiation, three types can be recognized: Typ-I drosopterinosomes appear first during metamorphosis and have clear limiting membranes and amorphous materials within. Those of type-II are found in abundance shortly after metamorphosis and have inner structures, consisting of fibrillae and/or small lamellae in dense concentric arrangement. Type-III is found abundantly in adults and acquires an almost homogeneously electron-dense mature morphology, probably from the deposition of electron-dense materials. On the basis of counts of pterinosomes, a successive transformation from type I to III is suggested. The differences among red drosopterinosomes, yellow sepiapterinosomes in xanthophore and melanosomes are not always distinguishable electron microscopically. Discrimination is possible by careful examination of lamellar patterns characteristic of the respective granules and by a simultaneous application of light and electron microscopy. From this viewpoint, a re-evaluation of the identification of granules previously reported was effected.
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  • 37
    ISSN: 1432-0878
    Keywords: Sympathetic ganglion ; Granule-containing cells ; Synapses ; Three-dimensional analysis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The surface of 4 granule-containing cells, in a cluster within the rat superior cervical ganglion, was studied by a serial sampling technique for electron microscopy. The result shows that all the 4 cells receive one, or three afferent synaptic boutons from the preganglionic fibers impinging upon their somata, and a somatic efferent synapse exists at two locations on each soma of the 2 of these cells. The postsynaptic element of the efferent synapse is observed to be represented by non-vesiculated and vesiculated segments of dendrites, soma and a possible axon collateral of the adrenergic principal neuron of the ganglion. There is a remarkably constant development of the attachment plaque between the granule-containing cells themselves, representing 1.7–2.3% of surface area for each cell. The surface area exposed to the extracellular space (covered only by a basal lamina) varies from 0.1 to 2.3% of the total perikaryal surface of the 4 cells. A tendency is noted that those cells without efferent synapses possess a more extensive area exposed to extracellular space than those forming somatic efferent synapse to the postganglionic elements.
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  • 38
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    Cell & tissue research 142 (1973), S. 1-12 
    ISSN: 1432-0878
    Keywords: Harderian gland ; Hamster ; Sexual dimorphism ; Alveolar cells ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The lobules of the Harderian glands of young male and female hamsters are widely separated by connective tissue and are made up of alveolar cells containing small vacuoles. There is considerable increase in the size of the lobules by 12 days. Based on size distribution of vacuoles two types of alveolar cells can be recognized in the male hamsters 4 weeks and older. The Harderian glands of 2-week animals of both sexes contain a black-brown pigment. The appearance of pigment is accompanied by a proliferation of membranes. In the female the amount of pigment increases with increasing age until 4 weeks of age and then remains at a relatively stable level. In the male no pigment was found after 4 weeks of age. Membrane-bounded juxtanuclear structures are present in the alveolar cells of both sexes until 3 weeks of age. These structures appear to play different roles in the male and female hamsters. The differentiation of the alveolar cells into light and dark types must take place during the 3rd week of postnatal development. A possible relationship between the levels of gonadal hormones and the occurrence of pigment at different ages in both sexes is also discussed.
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  • 39
    ISSN: 1432-0878
    Keywords: Crustacean CNS ; Olfactory and accessory lobes ; Glomerular neuropile ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The olfactory and accessory lobes of the crayfish, Cherax destructor contain glomeruli. Light microscope and electron microscope studies show that these glomeruli are the only regions of synaptic activity in the lobes and that at least four separate sets of axons meet within the glomeruli. The olfactory glomeruli are column shaped, complex structures with no large single pre- or postsynaptic elements. The accessory lobe glomeruli follow a more conventional pattern and each has one large axon ending in a terminal arborization where it makes synaptic contact with large numbers of smaller fibres. The large fibre is presynaptic.
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  • 40
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    Cell & tissue research 143 (1973), S. 117-133 
    ISSN: 1432-0878
    Keywords: Nervous system ; Ctenophores ; Intra-mesogleal nervous system ; Synapses ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural evidence is given of the occurrence of nervous elements in the mesoglea of Ctenophores based on the presence of the typical synapses of this phylum. In Beroids, nervous fibers from the ectodermal nerve-net cross the epithelial basal membrane and run through the mesoglea; they are devoid of any ensheathing cell. These neurites build highly differentiated synapses upon the muscles and upon peculiar cells, tentatively named mesenchymal cells. In Cydippids, nerve fibers and nerve cell-bodies have been observed in the mesoglea of the tentacles. The mesogleal core of each tentacle contains mesenchymal cells and a thick strand of neurons and neurites, forming a kind of elongated ganglion. Neurites of either the axial neurones or the epithelial nerve-net neurones form numerous radial nerve strands across the tentacular muscles. Interneural, neuro-muscular and neuro-mesenchymal junctions are very frequent in the tentacle. As far as the organization of the mesoglea is concerned, the Ctenophora thus appear closer to Turbellaria than to Cnidaria.
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  • 41
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    Cell & tissue research 146 (1973), S. 491-500 
    ISSN: 1432-0878
    Keywords: Hypothalamo-hypophysial system ; Pineal complex ; Rana esculenta ; Light/darkness ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary InRana esculenta the activity of the hypothalamo-hypophysial system has been investigated in intact and blinded animals, after removal of the frontal organ and after elimination of the whole pineal complex. The results on intact and blinded animals are practically the same as those found earlier inRana temporaria. Light increases the activity of the preoptic nucleus, blinding changes the difference between light- and darkness-treated intact animals. Compared with the intact animals the other two groups (without frontal organ and without pineal complex) show a marked increase in incorporation of35S-cysteine in the preoptic nucleus. A difference between the animals without frontal organ and those without pineal complex, however, can hardly be observed. It follows that the absence of the frontal organ has the same influence on the preoptic nucleus as elimination of the whole pineal complex. In intact animals the influence of the frontal organ on the preoptic nucleus consists of an inhibition of neurosecretory activity as well under light as under darkness conditions. The enhanced synthesis of labelled material in the preoptic nucleus after removal of the frontal organ, results in a transport along the hypothalamo-hypophysial tract mainly to the outer zone of the median eminence and not to the posterior lobe.
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  • 42
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    Cell & tissue research 147 (1973), S. 127-148 
    ISSN: 1432-0878
    Keywords: Melanophores (Teleost) ; Pigment migration, microtubules ; Colchicine, vinblastine ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The antimitotic drugs colchicine and vinblastine were applied to the melanophores of isolated scales of Pterophyllum scalare. The time course of inhibition of pigment migrations was studied quantitatively with the photoelectric method. Within one hour of treatment with 5 mM colchicine, a partial and reversible inhibition of pigment movements is obtained. During this time, the number of microtubules per cell process does not differ significantly from controls when pigment is dispersed. However, their number increases concomitantly with the decrease in rate of aggregation induced by KCl up to about the same value as in dispersed pigment cells. This indicates a close connection between pigment movements and the microtubule turnover known to occur in angelfish melanophores. When applied in a concentration of 0,2 mM, vinblastine has a total and irreversible effect on pigment movements, with an especially rapid and profound inhibition of pigment dispersion. The fine structure of vinblastine-treated melanophores is characterized by an almost complete loss of microtubules and the appearance of crystalloid bodies, which differ in fine structure from vinblastine-induced crystals of all other cell types so far examined. Possibly their peculiar structure is related to special properties of melanophore microtubules, such as rapid turnover and relatively high resistance to colchicine.
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  • 43
    ISSN: 1432-0878
    Keywords: Protein secretion ; Defensive glands ; Blatta orientalis ; Cytology ; Autoradiography ; Insekts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Im Bereich der abdominalen Tergite V-X und oberseits and den Zerzi liegt bei Nymphen beider Geschlechter und bei adulten Weibchen von Blatta orientalis statt des einschichtigen Epithels ein zweischichtiges Drüsengewebe vor, welches ein visköses Sekret aus Wasser, freien Aminosäuren (+ Glutamin), Oligo- und zahlreichen Polypeptiden auf die Tergitenoberfläche sezerniert. Die strukturelle Differenzierung des Drüsengewebes ist mit der Sekretionsaktivität korreliert, sowohl während der Ontogenese als auch im Bereich verschiedener Tergite (Maxima: weibliche Subimagines, Tergite VI und VII). Untersuchungen mittels hochauflösender quantitativer Autoradiographie ergaben, daß injizierte Aminosäuren im größten Teil der Drüsenzellen angereichert werden: Markierte Zellen zeigen Radioaktivität im reichlich ausgebildeten rauhen endoplasmatischen Retikulum, Golgi-Apparat, in Sekretgranula und in ihrem Endapparat. Dieser durchsetzt die Drüsenzelle als langer gewundener Kanal mit Bürstensaum, in welchen je eine darüberliegende Gangzelle einen chitinösen Ausführgang inseriert. Die gleichzeitige Anwesenheit von markierten und nicht markierten Zellen mit praktisch gleich stark entwickeltem endoplasmatischem Retikulum und Golgi-Apparat zeigt, daß die morphologische Ausbildung dieser mit der Proteinsekretion befaßten Organellen nicht unbedingt deren Aktivität reflektiert. Vereinzelt stehen Zellfortsätze mit den morphologischen Charakteristika neurosekretorischer Tätigkeit in direktem Kontakt mit Drüsenzellen. Eine Abwehrfunktion des viskösen Sekrets durch bloße mechanische Behinderung kleiner räuberischer Arthropoden wurde sichergestellt, wobei es dem Beutetier gelingt, zu flüchten. Weiters wurde ein zweiter Drüsenzelltyp beobachtet, der mit injizierten Aminosäuren nur schwach markierbar ist, ebenfalls einen Endapparat besitzt, jedoch arm an rauhem endoplasmatischem Retikulum und gleichzeitig reich an Mitochondrien, Golgi-Apparaten und kleinen Vesikeln ist. Die Funktion dieses zweiten Zelltyps ist zwar nicht sichergestellt, möglicherweise reguliert er jedoch die funktionell wichtige Viskosität des Sekretes.
    Notes: Summary A two-layered glandular tissue occurs on tergites V to X and on the cerci of juvenile specimens of both sexes and of adult females of Blatta orientalis, in place of the usual monolayer of epidermal cells. This gland tissue contains two cell types and secretes a viscous product of water, free amino acids (+ glutamine), oligo- and several polypeptides onto the tergal surface. The structural differentiation of the gland is correlated with secretory activity, both in different molting stages and in different tergites of an individual; maximal values are found in tergites VI und VII on last instar females. Applying quantitative radioautography on the electron microscope level, we found, that although the most common gland cell type contained an abundantly developed rough endoplasmic reticulum and Golgi-apparatus, characteristic of protein secreting cells, not all of them incorporated equally the injected amino acids. This is consistent with an asynchronous secretory cycle, also suggested by biochemical studies. Of great significance is the demonstration that the fine structural elaboration of the cellular organelles involved in protein synthesis cannot be used as a criterion for their ongoing activity. The secretion is discharged into an end-apparatus consisting of a tortuous canal with a brushborder that penetrates the whole gland cell. One unbranched chitinous duct, formed by a “duct carrying cell”, is inserted into the end-apparatus of each gland cell. Occasionally, cell processes exhibiting the typical morphological characteristics of neurosecretory cells are seen in direct contact with gland cells. A defensive function of the secretion which acts by mechanically impairing smaller predatory arthropods was ascertained. To achieve this effect and to allow the preyanimal to escape, the secretion has to be adjusted to a proper viscosity by an adequate dilution. This might be achieved by the second gland cell type, which was not selectively labelled by injected amino acids; this cell type contains an endapparatus, abundant mitochondria, Golgi-apparatuses and small vesicles, but only few profiles of rough endoplasmic reticulum.
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  • 44
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    Cell & tissue research 125 (1972), S. 306-331 
    ISSN: 1432-0878
    Keywords: Parenchyma of organs ; Rats ; Regeneration ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die sowohl nach singulärer 3H-Thymidin-Injektion als auch nach kontinuierlicher 3H-Thymidin-Dauerinfusion an Ratten erhobenen autoradiographischen Befunde lassen folgende Schlüsse ziehen: 1. Die während des Wachstums im Vergleich zum Ende der Foetalperiode ganz auffällige, unmittelbar postpartal nachweisbare Depression des 3H-Thymidin-Markierungs-Index im Parenchym von Leber, Niere und Pankreas wird auf eine funktionelle Umstellung und zumindest in der Leber auch auf eine strukturelle Umgestaltung bezogen. Schon am 30. Tag ergeben sich Anhaltspunkte für eine Umschaltung auf einen langsamen Proliferationsmodus, die bei 60 und 120 Tagen mit Halbierung der DNS-Syntheserate vollends abgeschlossen ist. 2. In der kompensatorisch regenerierenden Leber nach 2/3-Teilhepatektomie wird der Anteil nicht proliferierender Zellen — d.h. die non growth fraction — von juvenilen über eben ausgewachsene bis zu senilen Tieren kontinuierlich größer. 3. Bei der reparativen Regeneration in der unterbundenen Niere nach temporärer 1stündiger Ischämie ist der Proliferationsumfang in den am stärksten geschädigten Nephronabschnitten auch am größten. Es führt das Stratum subcorticale, dann folgt die Zona intermedia, das Stratum labyrinthicum und die Zona basalis. 4. Demgegenüber weist die Topik proliferierender Zellen bei kompensatorischer Nierenregeneration nach kontralateraler Ischämie bzw. Nephrektomie wohl quantitative aber keine qualitativen Unterschiede zu der beim physiologischen Zellersatz von Kontrollen auf. Das Stratum labyrinthicum zeigt die höchsten Werte und dann stellt sich eine stufenweise erfolgende Abnahme der prozentualen Markierung über das Stratum subcorticale zur Zona intermedia und Zona basalis ein. 5. Anhand der autoradiographischen Daten wird ein Modell für die Proliferation von Leberepithelien juveniler und ausgewachsener Ratten entworfen. Weiter befaßt sich dieses Modell mit der Zellneubildung nach Teilhepatektomie im Verlauf und nach Abschluß der Regeneration. Nach den entwickelten Vorstellungen wirkt eine partielle Hepatektomie an ausgewachsenen und senilen Tieren durch Verkleinerung der non growth fraction und Vergrößerung des proliferating pools im Sinne einer Verjüngerung der proliferatorischen Potenz des Leberepithels.
    Notes: Summary The autoradiographic results reported, are obtained on rats after single injections of 3H-thymidine as well as continuous 3H-thymidine infusions. They lead to the following conclusions: 1. Compared to the end of embryonic development the 3H-labelling index in parenchyma of liver (epithelium), kidney (tubule), and exocrine pancreas (acinus) is depressed during the first day of postnatal growth. From 1–4 days postpartal fluctuations occur, afterwards the labelling index increases between 7 and 12 days and from there on a decrease is observed up to 120 days. This depression and fluctuation of the labelling index is probably connected with a functional transposition and, especially in the liver, with a structural transformation. The reduction of the mean grain density of labelled nuclei by about a factor of 2, begins already at day 30 and is completed on day 60 and 120. It depends on a reduction of the rate of DNA synthesis. This might be explained as a consequence of a commutation from the rapid to the slow mode of cellular proliferation. 2. In the compensatory regenerating liver after 2/3 partial hepatectomy the portion of non labelled nuclei—i.e. the non growth fraction—increases continuously from juvenile to young adult and especially up to senile animals after a postoperative continuous 3H-thymidine infusion. 3. During reparative regeneration in the ligatured kidney following temporal (1 h) ischaemia the extent of proliferation after postoperative continuous 3H-thymidine infusion is hightest in those regions of the nephron with the largest postischaemic damage. The percentage of labelled nuclei decreases from the stratum subcorticale to the zona intermedia, stratum labyrinthicum, and zona basalis. 4. On the other hand only quantitative but not qualitative differences exist in the topic of proliferating cells between compensatory regeneration in the unligaturated kidney after contralateral temporal ischaemia or nephrectomy and the physiological cell renewal of controls. After continuous 3H-thymidine infusions the highest percentage of labelled cells is observed within the stratum labyrinthicum and then a gradual decrease occurs from there to the stratum subcorticale, zona intermedia and basalis. Thus, cellular proliferation in compensatory regeneration of the kidney is only an enhanced form of those proliferative processes occuring during physiological cell renewal. 5. With the autoradiographic data a model concerning proliferation of liver epithelia in juvenile and adult rats has been constructed. Furthermore this model deals with cell renewal during and after regeneration following partial hepatectomy. The conclusion is, that partial hepatectomy diminishes the non growth fraction and enlarges the proliferating pool. Thus this operation acts as a rejuvenating process in the proliferating potency of liver epithelia.
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  • 45
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    Cell & tissue research 149 (1974), S. 205-221 
    ISSN: 1432-0878
    Keywords: Locus coeruleus ; Tegmentum ; Mesencephalon ; Adrenergic centers ; Synapses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The locus coeruleus of cat is populated by two types of neurons: medium sized ones, with plump cell bodies and relatively short dendrites; and small ones, with triangular bodies and relatively long dendrites. The former type is regarded here as typical of the centre, whereas the second type could simply represent displaced neurons from the adjacent griseum centrale. Electron microscopy failed to reveal any outstanding richness in pigment granules in kittens up to five weeks old. Very characteristic somatic appendages were found, mostly in the medium sized neurons. These somatic “spines” communicate with the perikaryon by means of a narrow neck region. A complex, multilayered, glial sheath surrounds the cells. This glial sheath is pierced by the somatic appendages, which are not surrounded by glia and make contact with axonal knobs. Typical dendritic spines appear to be absent. Axodendritic synapses are made on medium sized dendritic trunks. By and large, most of the synaptic vesicles present in the centre are of the small, clear-centered type. However, dense core vesicles extremely variegated in size and appearance were found, both in presynaptic and postsynaptic profiles. The possibility that dense core vesicles should be regarded as atypical lysosomes rich in by-products of the metabolism of catecholamines (melanine) has been considered.
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  • 46
    ISSN: 1432-0878
    Keywords: Sea anemone mesoglea ; Collagen synthesis ; Epitheliomuscular cells ; Electron microscopy ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary Electron microscopy and autoradiography (H3-proline) were used to determine the cell(s) responsible for collagen synthesis and lamination in the mesoglea of the sea anemone, Aiptasia diaphana. Mesogleal collagen is synthesized by the epidermal epitheliomuscular cells which contain much rough endoplasmic reticulum, and secretory vesicles attached to microtubules which cross the basal plasmalemma and anchor in the basement membrane; these cells incorporate large amounts of H3-proline. The mesogleal collagen fibers are non-striated, have clear centers, and a diameter of 200–260 Å; their walls are composed of 65 Å diameter subunit fibrils which appear to be helically oriented. Epitheliomuscular cells rest upon a subepidermal basement membrane which is composed of mesogleal collagen fibers, 65 Å subunit fibrils, and dense granules. This subepidermal basement membrane labels definitively with H3-proline, and is the region where soluble collagen precursors apparently form subunit fibrils which associate to yield mesogleal fibers. The columnar mesogleal collagen fibers are arranged to form layers: the fibers of each layer have the same longitudinal orientation, while those of adjacent layers display an approximate orthogonal arrangement. It is felt that the subepidermal basement membrane is responsible for this organization of mesogleal fibers. Mesogleal amoebocytes do not label with H3-proline and show no ultrastructural evidence of collagen secretion.
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  • 47
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    Cell & tissue research 144 (1973), S. 489-509 
    ISSN: 1432-0878
    Keywords: Gills ; Scyliorhinus canicula ; Circulation sphincters ; Hydrostatic skeleton ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The anatomy of the blood supply to the gills of the dogfish, Scyliorhinus canicula, is described. The anatomical basis for a counter-current exchange system at the respiratory surfaces is reported. Within the interbranchial septum there is a capillary network joining all the afferent branchial arterioles of the gill. The structure of the walls of the corpus cavernosum is found to be of smooth muscle cells supported by a basal lamina and connective tissue and lined by endothelial cells containing phagocytic vesicles. Both the capillary network and corpus cavernosum are suggested to function in smoothing the pressure pulses of the blood flow. Pre- and post-lamellar vessels and pre- and post-lamellar sphincters are described. The sphincters are thought to control the number of secondary lamellae physiologically in the respiratory circuit, and by retaining blood within nonperfused lamellae to act in conjunction with pillar cells (contracting in antagonism to the hydrostatic skeleton of the blood) to maintain the rigidity of secondary lamellae in the water current. Whorls of cells of unknown function are found within the interbranchial septum. In the epithelium lining the water channel large cells having a complexly branching plasma membrane and a very large central vacuole occurs. The cytoplasm lining the lumen contains numerous vacuoles each surrounded by a double membrane.
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  • 48
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    Cell & tissue research 151 (1974), S. 281-292 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Mitochondria ; ACTH ; DNA-synthesis ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of a chronic ACTH administration (up to 12 consecutive days) on the 3H-thymidine uptake by the mitochondrial compartment of rat adrenal zona fasciculata were investigated by high resolution autoradiography, and compared with the changes in volume and number per cell of these organelles induced by the hormonal treatment. Up to the 9th day of treatment there is a significant increase in the tracer incorporation into adrenocortical mitochondria which is coupled with a significant increase in the volume of the organelles. After 12 days of hormone administration a significant decrease in the 3H-thymidine mitochondrial uptake is found, which is associated with a conspicuous increase in the number of mitochondria per cell and a net decrease in their average volume. The data are discussed in the light of evidence indicating that mitochondria possess a genetic apparatus largely independent of nuclear control. It is hypothesized that ACTH controls the growth and proliferation of adrenocortical mitochondria and that the mechanism of this action of ACTH involves stimulation of the mitochondrial DNA synthesis.
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  • 49
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    Cell & tissue research 151 (1974), S. 369-384 
    ISSN: 1432-0878
    Keywords: Giant dopamine neurone ; Planorbis corneus ; Localization of dopamine ; Axon tracing ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary There is a giant dopamine-containing cell (GDC) in the left pedal ganglion of Planorbis corneus. Some presynaptic endings of the GDC are located within the visceral and left parietal ganglia, other endings are located peripherally. Dense-cored vesicles of 50–250 nm diameter were observed in the perikaryon and primary axon of the GDC. Electron microscope histochemistry suggests that these vesicles contain dopamine. Vesicles with a similar appearance are present in some axonal processes located in areas of the nervous system known to contain presynaptic endings of the GDC. This neurone offers unique advantages for studying the role of neuronal dopamine.
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  • 50
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    Cell & tissue research 151 (1974), S. 489-498 
    ISSN: 1432-0878
    Keywords: Limbic system ; Cat ; Amygdaloid body ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present study was undertaken to re-examine the central nucleus of the cat in Nissl stained sections, to describe its fine structural characteristics, and to compare the lateral subdivision of this nucleus with the putamen. In Nissl preparations, it was observed that the lateral subdivision of the central nucleus contains a fairly homogeneous population of small cells while the putamen contains both small and large cells. It is the presence of a few large cells at the lateral periphery of the lateral part of the central nucleus that makes the boundary between the two nuclei indistinct. Examination of the fine structure of the medial and lateral subdivisions of the central nucleus revealed the presence of many boutons containing flattened vesicles and fewer with spheroid vesicles. In contrast, most of the boutons in the putamen have spheroid vesicles. It is concluded that the lateral subdivision of the central nucleus may be distinguished from the putamen, except at its most lateral border, by its homogeneous population of small cells and its many boutons containing flattened vesicles.
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  • 51
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    Cell & tissue research 152 (1974), S. 299-303 
    ISSN: 1432-0878
    Keywords: Post-capillary venules ; Mice ; Pathway of B lymphocytes ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histological observation on the mesenteric lymph node and Peyer's patches of C3H B mice, neonatally thymectomized, lethally irradiated and reconstituted with syngeneic bone marrow cells, showed that a large number of lymphocytes appeared selectively in the restricted territory surrounding the post-capillary venules. Severe depletion of lymphocytes persisted in most of the thymus-dependent areas. Lymphocytes were also observed passing through the walls of the post-capillary venules. Autoradiographic studies on the mesenteric lymph node of recipient B mice 30 minutes after intravenous injection of cells labelled with 3H-uridine and taken from lymph nodes of donor B mice showed that B lymphocytes could penetrate the walls of the post-capillary venules from the blood into the peripheral lymphoid tissues. The post-capillary venules, which are known as the recirculating route of T lymphocytes in normal animals, are thought to be the pathway of migrating B lymphocytes in B mice.
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  • 52
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    Cell & tissue research 152 (1974), S. 283-292 
    ISSN: 1432-0878
    Keywords: Sense organ ; Lateral line ; Synapses ; Ambystoma mexicanum ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Lateral line organs in young salamanders of the species Ambystoma mexicanum were investigated with scanning and transmission electron microscopy. They were found to differ from the lateral line organs in adult animals (1) by being lower, having short hair cells and supporting cells, (2) by the hair cells having areas of lateral contact, (3) by the occasional presence, at the edge of the organ, of hair cells at an early developmental stage. Two types of nerve endings are seen: (1) afferent, and (2) less commonly, efferent vesiculated ones. Synaptic bodies have been seen in the cytoplasm without association to afferent synapses.
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  • 53
    ISSN: 1432-0878
    Keywords: Hypothalamic neurosecretory system (rat) ; Adrenal cortex ; 35S-cysteine incorporation ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The incorporation of 35S-labelled cysteine in the hypothalamic-neurohypophyseal system was studied in normal and adrenalectomized rats and in rats treated with excess hydrocortisone. Labelled cysteine was intraperitoneally administered and grain counts were made of autoradiographs produced from sections of the supraoptic and paraventricular nucleus, median eminence and neurohypophysis of animals killed 45 min., 4 hours and 24 hours after administration of the labelled substance. On the whole, lower incorporation levels of the label were noted in the adrenalectomized rats, compared with the controls. In the rats treated with excess hydrocortisone, the grain counts at 45 min and 4 hours after injection were higher and those at 24 hours were lower than those of the controls. The findings are discussed, among other things, in terms of rate of uptake vs. time and related to previous reports on the cysteine uptake and neurosecretory activity of the hypothalamic-neurosecretory sytem.
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  • 54
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    Cell & tissue research 152 (1974), S. 513-523 
    ISSN: 1432-0878
    Keywords: Ovary ; Corpus luteum ; Innervation ; Fluorescence histochemistry ; Electron microscopy ; Quantitative study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Qualitative and quantitative studies were made to determine the amount of nerve fiber supplying corpora lutea (CL) of rats during the oestrous cycle and pregnancy and sow CL during days 4–6 after ovulation. Fluorescence microscopy of freeze-dried, paraformaldehyde treated (Falck-Hillarp method) rat ovaries reveals adrenergic nerve fibers which run along with vessels and form a network among interstitial gland cells. Nerve fibers do not enter the granulosa cell layer in follicles or CL. In the CL circumference both vascular and non-vascular nerves occur the latter being related to the fibromuscular layer and probably innervating smooth muscle cells. No striking differences exist between the innervation of the ovary in non-pregnant and pregnant rats. Bodian and methylene blue staining did not contribute to a more detailed knowledge of rat ovary nerve supply. Electron microscopic quantitative analysis of rat and pig CL (rat: day 18 of pregnancy; pig: day 4–6 after ovulation) revealed no axon profiles in 2.000 grid squares (one square measuring 2.25×10-2 mm2) of randomly taken CL sections. Thus it was possible to calculate an upper limit of 133 μm of nerve fibers per 1 mm3 CL tissue, in case there were any at all.
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  • 55
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    Cell & tissue research 153 (1974), S. 219-226 
    ISSN: 1432-0878
    Keywords: Cerebellar cortex ; Man and other mammals ; Golgi cells ; Regional differences ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The number of Golgi cells per unit volume was determined in different regions of the cerebellar cortex of man and of ten other mammals. Despite the general belief in the uniform architecture of the cerebellar cortex, regional differences in the distribution of Golgi cells were found. In the inferior parts of the vermis, the number of Golgi cells per unit volume is twice that in the corresponding hemispheres. In addition, there are differences between the anterior and inferior parts of the vermis. These differences are a feature of the cytoarchitecture of the cerebellum in man and all the investigated mammals. The ratio of Purkinje cells to Golgi cells was also determined and found to differ in different species. In man, this ratio is 1∶1.5, while in the monkey and cat it is almost 1∶1.9 and in the rat 1∶3.3. These differences in the ratio of Purkinje cells to Golgi cells are discussed from the point of view of cerebellar evolution.
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  • 56
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    Cell & tissue research 153 (1974), S. 383-398 
    ISSN: 1432-0878
    Keywords: Aesthete Organs ; Lepidochitona cinereus ; Cell types ; Secretory cells ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary The structure of the aesthete organs of the chiton Lepidochitona cinereus (L.) is described by light and electron microscopy. The observations do not discount a sensory function for these organs, but possible sensory structures such as microvilli and cilia are poorly organised. Most of the aesthete is taken up with large cells actively forming secretory products and apparently passing them proximally in the aesthete canal towards the animal. Comparisons are drawn with the brachiopod caecae.
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  • 57
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    Cell & tissue research 153 (1974), S. 399-413 
    ISSN: 1432-0878
    Keywords: Spinal ganglia (Rat) ; Cell division ; Autoradiography ; Neurone morphogenesis ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pulse labelling with tritiated thymidine was used to determine the time of the final division of the neuroblasts which subsequently form rat lumbar dorsal root ganglion neurones. The final division occurred during a 4 day period, the maximum frequency being on day 12 of gestation. Separation of the ganglion cells into large light neurones and small dark neurones showed that the large light neurones were formed earlier than the small dark neurones. In both cases the final divisions occurred over a period of 3–4 days, but the peak rate of formation of large neurones was on day 12, and that of the small neurones was on day 13. Low power electron micrographs were used to measure mean cell diameter throughout development from day 11 of gestation until a postnatal age of 225 days. A marked increase in cell diameter occurred on day 15–15.5, about 3 days after the final cell divisions of the majority of the cells. The rate of growth increased just before birth, but no increase in mean cell diameter was found between day 21 of gestation and the third day postnatal. The growth was again rapid after this period until a plateau in cell diameter was reached about 33 days after birth.
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    Cell & tissue research 154 (1974), S. 231-249 
    ISSN: 1432-0878
    Keywords: Pituitary ; Goldfish ; Innervation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the pituitary gland of Carassius auratus was studied by light and electron microscopy under various physiological and experimental conditions to investigate whether or not neurosecretory fibres play a role in regulating pars distalis function. Two types of neurosecretory fibre (Type A and Type B) were distinguished. Prolactin, ACTH and TSH1 cells were innervated by Type B fibre terminals separated from the endocrine cells by a continuous basal lamina (“indirect contacts”). Gonadotropic, STH and TSH2 cells were innervated by Type A as well as Type B neurosecretory fibres, mostly without an intervening basal lamina (“direct contacts”). The assessment of the amount of neurosecretory granules and microvesicles in nerve terminals during the pre-spawning, spawning and postspawning seasons and following the administration of Oestradiol, Thyroxine, Thiourea and Metopiron respectively revealed convincing evidence for a participation in pars distalis control for Type A and Type B fibres innervating gonadotropic cells and STH cells and Type B fibres innervating TSH2 and ACTH cells. Immediately after spawning both nerve fibre types innervating gonadotropic cells and Type A fibres innervating STH cells showed a striking decrease in the amount of dense core vesicles. During the spawning season nerve fibres innervating somatotropic cells, TSH2 cells and ACTH cells also undergo changes suggesting that prior to spawning major changes in the endocrine system of the goldfish take place.—These results point to a dual control, by peptides and amines, of teleost pars distalis function.
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  • 59
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    Cell & tissue research 155 (1974), S. 291-320 
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Chicken ; Developmental endocrinology ; Epithelial differentiation ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary Anlagen of the pars distalis (Rathke's pouch), adjacent ectoderm, endoderm, infundibulum and mesenchyme left in situ were put in 3% glutaraldehyde between 1–3 pm and fixed overnight. Epon sections of this material from six White Leghorn, Gallus gallus, embryos fixed at each stage, and of two control partes distales from laying hens of the same flock were examined. At stage 17 (∼12 hours after formation) Rathke's pouch cells were stratified, uninnervated, non-vascularized and stellate, with high nucleo-cytoplasmic ratios and few organelles. Except for lipid inclusions, pouch cells did not appear appreciably different by stage 27, either regionally within the pouch wall or from the adjacent epithelioid cells. Apparent major changes indicative of cytoplasmic maturation by stage 27 included: reduction in number of polysomes; appearance of single-membraned, dumb-bell shaped to rounded, dense granula which were usually in basal position but also in areas of the Golgi apparatus; greater prominence of rough endoplasmic reticulum with cisternae containing dense material, and of the Golgi apparatus, notably with variously dense and/or coated vesicles and material; reduction in lipid inclusions by stage 24. Non-terminating axons in the infundibulum were first seen at stage 27. We found no convincing evidence for any possible morphogenetic or other relationship between the pars distalis and surrounding tissues. “Melanophore-stimulating hormone-activity”, reported to appear on day 5 of incubation, “stored thyroid-stimulating hormone” or pars distalis hormone granula or activities could not be identified. Rathke's pouch and other epithelioid structures may have been secreting, taking up nutrients and/or differentiating, activities which could be important for yolk sac development, nutrition and/or cytodifferentiation, respectively.
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    Cell & tissue research 139 (1973), S. 1-27 
    ISSN: 1432-0878
    Keywords: Glandulomuscular cells ; Hydra ; Basal disk ; Light and electron microscopy
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    Notes: Summary The glandulomuscular cells of Hydra are located exclusively in the basal disk. They are derived from epithelio-muscular cells which have been forced proximally. Light and electron microscopical studies show that prior to their destruction and elimination, the transformed epithelio-muscular cells (i.e. the glandulomuscular cells) undergo certain striking morphological and physiological changes. Golgi complexes and elements of rough E. R. increase remarkably in activity, and individually or jointly produce at least six types of morphologically different droplets. One additional type of droplet is thought to originate from neighboring digestive cells. Although the chemical nature of the individual droplets is uncertain, it is known that some are Alcian blue and PAS positive and contain hyaluronic acid. These evidences suggest the presence of an acid mucopolysaccharide material, the adhesive agent which attaches the animal to a substrate. The myonemes contain thick (200 Å in diameter) and thin (60 Å in diameter) filaments as in epithelio-muscular cells. There are also filaments of intermediate sizes and large fibers (770 Å in diameter). The myonemes are oriented radially with respect to the aboral pore and therefore in addition to contributing to the contraction and relaxation of the body column, they apparently regulate the opening and closing of the aboral pore. Although there is no evidence to substantiate the mechanism for transformation of epithelio-muscular cells to glandulomuscular cells as well as cell death of the latter cell types, these problems are discussed briefly.
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    Cell & tissue research 139 (1973), S. 29-45 
    ISSN: 1432-0878
    Keywords: Nerve cells ; Hydra ; Basal disk ; Epithelial cells ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In addition to glandulomuscular cells, three other cell types are found in the basal disk of Hydra. These are interstitial cells, cnidoblasts and nerve cells. Although only a few of the two former cell types are recognized in this region, the observations from this study refute previous statements to the contrary. Nerve cells are concentrated in the basal disk where they form a type of “network” system, due to the presence of bipolar, tripolar and multipolar cells. In some specimens, they assume a circular arrangement around the base of the polyp. Using morphological criteria for identifying the three types of epidermal nerve cells (neurosensory, neurosecretory and ganglionic) in other body regions, only neurosensory and neurosecretory cells are observed in the basal disk. These are indistinguishable ultrastructurally from their respective counterparts in other regions. It is possible that ganglionic cells are also present in the basal disk, but there may be few such cells. It is suggested that the three cell types originate from the budding region and these precursor cells are then forced proximally. Interstitial cells, escaping their differentiative function, do not develop apparently into other cell types of the basal disk. Cnidoblasts contain normal nematocysts but their functional ability is uncertain. Neurosensory and neurosecretory cells arise directly and independently from interstitial cells in the budding region, as evidenced by the appearance of immature nerve cells in the peduncle and their absence in the basal disk. Although viable cells may be discarded from the basal disk, it is believed that most cells die in situ and are then eliminated. The possible role of nerve cells is discussed briefly.
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  • 62
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    Cell & tissue research 139 (1973), S. 369-396 
    ISSN: 1432-0878
    Keywords: Synapses ; Giant fibres ; Ventral nerve cord ; Lumbricus terrestris L. ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die proximalen Kollateralen der dorsalen Riesenfasern des Regenwurms wurden in Serienschnitten vom Soma bis zum Eintritt in die Riesenfaser verfolgt und im Hinblick auf ihre Feinstruktur und ihre synaptischen Kontakte Untersucht. Es finden sich sowohl chemische als auch elektrische Synapsen. Ihre Feinstruktur wird mit der bekannter Synapsen anderer Wirbellosen und Wirbeltiere verglichen. In beiden Riesenfasersystemen kommen efferente chemische Synapsen mit feinen postsynaptischen Verzweigungen vor, die anscheinend von Bauchmark-Motoneuronen stammen. Das Axon der medianen Riesenfaser weist darüber hinaus nur noch eine elektrische Synapse mit den Rieseninterneuronen auf. Demgegenüber erhalten die Kollateralen der lateralen Riesenfasern zahlreiche Afferenzen, die zum Teil als sensorische Fasern der Epidermis, multisegmentale Fasern der Hauptfaserzüge und Rieseninterneurone identifiziert werden konnten. Weitere Afferenzen stammen vermutlich von unisegmentalen Interneuronen her. Beide lateralen Riesenzellaxone bilden außerdem miteinander eine elektrische Chiasma-Synapse mit besonderen Membraneinfaltungen.
    Notes: Summary The proximal collaterals of the dorsal giant fibres of the earthworm were traced through serial sections from the cell bodies to the giant axons. Their structure and synaptic connections were examined. There are chemical as well as electrical synapses. Their fine structure is compared to that of other known invertebrate and vertebrate synapses. Both giant fibre systems have efferent chemical connections with thin postsynaptic arborizations which probably belong to ventral cord motoneurons. Moreover the median giant axon is connected by an electrical synapse with the giant interneurons. The lateral giant collaterals on the contrary receive many afferences through chemical synapses which were partly identified as sensory fibers from the epidermis, multisegmental axons from the main fibre bundles or giant interneurones. Other afferences probably come from unisegmental interneurones. In addition both lateral giant axons form an electrical chiasma synapse with special membrane folds.
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  • 63
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    Keywords: Caecal epithelium ; Trematodes, Cercariae ; Extracellular membranes, Membranous whorls ; Light and electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary The intestinal caeca of the intraredial cercaria of Neophasis lageniformis differ in several aspects from previous descriptions of the intestinal caeca of other digenetic trematodes. The caeca are lined with a single-layered, non-syncytial epithelium with lamellate projections into the lumen. The cells are rich in glycogen particles and contain abundant granular endoplasmic reticulum. The apical cell membrane, which displays a unit membrane structure, is always covered by an external membrane of the same thickness as a unit membrane but showing no double-layered substructure. The external membrane, which is not equivalent to a glycocalyx, may continue from one cell to another. Apically on the projections the external membranes are apparently pushed out forming large, extracellular whorls, which fill up the caecal lumen. In the lumen there are also found crystal-like structures and lipid-like bodies which are suspended in a granular substance. The possible origin and function of the extracellular bodies are discussed.
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  • 64
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    Cell & tissue research 139 (1973), S. 431-450 
    ISSN: 1432-0878
    Keywords: Cardiac muscle ; Frog ; Regeneration ; Electron microscopy ; Autoradiography
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    Topics: Biology , Medicine
    Notes: Summary From the 5th day up to the end of 3rd week following local crushing of the frog ventricle myocardium, ca. 13% of myocyte nuclei, in the vicinity of the damaged zone, were labelled after a single 3H-thymidine (3HTdr) injection, and 30–50% of these were labelled after repeated 3HTdr administration. The number of myocyte mitoses was maximal (ca. 1.3%) at the beginning of the 3rd week. The reactive proliferation of myocytes was accompanied by their “partial dedifferentiation”. This involved the nuclear euchromatic rearrangement, increase in size of nuclei and nucleoli, accumulation of the sarcoplasm rich in free ribosomes and rough endoplasmic reticulum, hyperplasia of the Golgi apparatus, and the appearance of 80–100 Å in diameter cytofilaments. Electron microscope autoradiography has shown that all these changes may be more or less pronounced in myocytes incorporating 3HTdr. The myofibril ultrastructure was found to be unchanged during S phase. However, in the mitotically dividing myocytes, the majority of Z-disks were disintegrated resulting in progressive release of myofilament bundles. Both 3HTdr labelled and mitotic myocytes were anchored to the adjacent ones by desmosomes and intercalated disks. No free myoblasts were observed.
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  • 65
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    Cell & tissue research 138 (1973), S. 113-132 
    ISSN: 1432-0878
    Keywords: Eggs ; Insects (Triatoma infestans) ; Embryogenesis ; Envelopes, Permeability ; Light and electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary The thick rigid chorion of the egg of Triatoma secreted by the follicle cells shows two porous layers: an aerial layer in the exochorion, an alveolar one in the endochorion. The anterior part of the eggshell is closed up by an operculum which is heaved up by the hatching larva. The operculum has no alveolar layer. The air enters through the numerous holes of the shell surface into the aerial layer and through the micropyles into the alveolar layer. The egg has no respiratory plastron. The follicle cells produce also a vitelline envelope whose structure shows a rapid condensation at fertilization time. During its development the embryo secretes two layers: serosal and embryonic cuticle. At high humidities, at low temperatures the egg is able to increase its weight during the early stages of embryogenesis, and this increase stops when the serosal cuticle is secreted. In a dry atmosphere the egg loses water but can develop if the temperature is higher than 20°C. The little permeability of the egg is related to the structure of its envelopes. The chorion and the vitelline envelope prevent the water from getting out of the egg. The serosal cuticle seems to be opposed to the penetration of the water into the egg. The role of the embryonic cuticle is probably limited in the transit of water.
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  • 66
    ISSN: 1432-0878
    Keywords: Iris ; Muscle, Nerves ; Light and electron microscopy ; Acetylcholinesterase ; 6-Hydroxydopamine
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    Notes: Summary The adrenergic and cholinergic innervation to the rat iris has been studied at a light and electron microscopic level. Catecholamine fluorescence histochemistry showed adrenergic nerves to be present in both the dilatator and the constrictor pupillae regions. At a fine structural level the terminal innervation of the iris was studied and criteria for the differentiation between presumptive adrenergic and presumptive cholinergic axon terminals were examined. To aid this examination presumptive adrenergic axons were either labelled with the “false” adrenergic transmitter, 5-hydroxydopamine, or chemical sympathectomy performed using 6-hydroxydopamine. The value of using acetylcholinesterase staining as a marker for cholinergic nerve terminals was also studied. Results showed a mixed adrenergic/cholinergic innervation to the dilatator pupillae. In the constrictor pupillae an exclusively cholinergic innervation was found although adrenergic and cholinergic nerves were found supplying the blood vessels and at the dilatator-constrictor interface. These findings are discussed with regard to innervation-function relationships in the iris.
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    Cell & tissue research 138 (1973), S. 315-326 
    ISSN: 1432-0878
    Keywords: Olfactory mucosa ; Frog ; Innervation ; Ultrastructure ; Light and electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary The olfactory mucosa of frog has been studied at an ultrastructural level to confirm previous light microscope observations in regard to the presence, in the sensory epithelium, of nerve fibres not belonging to the first cranial nerve proper. It has been observed that both myelinated and unmyelinated nerve fibres are present in the lamina propria and that eventually these fibres terminate inside the epithelium. Unmyelinated fibres usually contain dark core vesicles and similar content is seen in their intraepithelium terminals. Terminals containing only clear vesicles are also observed in the epithelium and they are believed to represent the terminals of the myelinated fibres. The significance of these ultrastructural findings is discussed in view of their functional meaning.
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    Cell & tissue research 141 (1973), S. 203-221 
    ISSN: 1432-0878
    Keywords: Median eminence ; Newt ; Zones ; Light and electron microscopy
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    Notes: Summary In the median eminence of the newt a medial region and two lateral regions are described. In cross section, the medial region appears to be made up of 1) an outer or glandular zone (Zone I) containing aldehyde-thionine-positive and negative nerve fibres and blood capillaries. Nerve fibres appear aligned in palisade array along the capillaries. 2) An inner zone (Zone II) made up of a) a layer of aldehyde-thionine-positive nerve fibres (fibrous layer) belonging to the preoptic hypophyseal tract and b) a layer of ependymal cells lining the infundibular lumen and reaching the blood vessels with their long processes. The lateral regions display a less pronounced stratification and aldehyde-thionine positive nerve fibres are nearly absent. A slender lamina (ependymal border) containing mainly aldehyde-thionine-positive nerve fibres and ependymal cells connects the median eminence to the pars nervosa. At the ultrastructural level, in the outer zone of the medial region at least 4 types of nerve fibres and nerve endings are identified: Type I nerve fibres containing granular vesicles of 700–1000 Å and clear vesicles (250–400 Å). Type II nerve fibres containing granular vesicles and polymorphous granules of 900–1300 Å and clear vesicles (250–400 Å). Type III nerve fibres containing dense granules of 1200–2000 Å and clear vesicles of 250–400 Å. Type IV nerve fibres containing only clear vesicles of 250–400 Å. In the inner zone too, all these nerve fiber types are found among ependymal cells, while the fibrous layer consists of nerve fibres containing granules of 1200–2000 Å in diameter. In the lateral regions Type I, Type II and Type IV nerve fibres and their respective perivascular terminals are found; axons containing dense granules (1200–2000 Å) are scanty. In these regions typical synapses between Type I nerve fibres and processes rich in microtubules are visible. The classification and functional significance of nerve fibres in the median eminence are still unsolved, but it may be assumed that nerve fibres of the medial region belong to both the preoptic hypophyseal and tubero hypophyseal tract, while the lateral regions are characterized by nerve fibres of the tubero hypophyseal tract. Peculiar specializations of the ependymal cells in the median eminence of the newt are also discussed.
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    Cell & tissue research 141 (1973), S. 301-317 
    ISSN: 1432-0878
    Keywords: Cnidaria ; Nervous system ; Synapses
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    Topics: Biology , Medicine
    Notes: Summary The nervous system of juvenile and adult Ceriantheopsis americanus has been examined with the electron microscope. The nervous system is exclusively ectodermal, forming a plexus of fibres lying between the epithelium and the muscle layer. The plexus consists of three types of nerve fibre that vary in diameter from 0.1 to 20 μ, and a fourth type of fibre of uncertain nature. The reticulum, previously thought to be the ectodermal nervous system, is redescribed as the peduncles of epithelial supporting cells. Intraneural and neuromuscular synapses are described. About 97% of the interneural are polarized. The unpolarized synapses are a variety not previously described, consisting of a series of polarized zones, for which the name multipolarized synapse is proposed. Structurally, the interneural synapses are more complex than those previously seen in the Cnidaria. Presynaptic projections, periodic cleft densities, and a postsynaptic web are described. By contrast, the neuromuscular synapses bear no membrane specializations. On the basis of observed synaptic interactions of its components a preliminary model of the functional organization of the nervous system is proposed.
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  • 70
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    Keywords: Chloride cells ; Eel ; Gills ; Ionic transport ; Autoradiography
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    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Nous avons montré par une technique autoradiographique que les ions Cl− et Na+ sont concentrés dans les cellules à chlorure de la branchie d'anguille adaptée à l'eau de mer. La signification de cette accumulation ionique plus marquée vers le pôle apical de ces cellules a été discutée par rapport à l'excrétion branchiale de ces ions en eau de mer.
    Notes: Summary With an autoradiographic technique Cl− and Na+ ions have been shown to be localized in the chloride cells of sea water eel gills. The significance of this accumulation, more marked towards the apical pole of these cells, is discussed with regard to branchial excretion of these ions in sea water.
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  • 71
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    Cell & tissue research 145 (1973), S. 119-129 
    ISSN: 1432-0878
    Keywords: Iris ; Cephalopod (Octopus vulgaris.) ; Chromatophore ; Innervation ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary The Octopus iris is composed of five different layers: A, the external epithelium; B, the chromatophore layer; C, the iridocyte layer; D, the layer of muscles and collagen strands; E, the pigment epithelium. The nerves innervating the sphincter and the chromatophore muscles are identified and their neuromuscular junction is described. The motor endings of chromatophore nerves have an additional ending in presynaptic position which probably functions as a modifier of neuromuscular transmission. The chromatophores are naked and exhibit a tubular channel system between plasmalemma and pigment container which looks similar to the T-system of muscle cells.
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    Cell & tissue research 146 (1973), S. 45-67 
    ISSN: 1432-0878
    Keywords: Cerebellum (rat) ; Growth in Tissue culture ; Cell types ; Light and electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary The outgrowth of newborn rat cerebellum cultivated in the Maximow assembly was studied from the time of explanation until the end of the 1st week “in vitro”. Dynamic characteristics of migrating cells were investigated with time lapse microcinematography and with phase and interference contrast. Three types of cells were identified: bipolar fusiform cells, fibroblasts and macrophages. The ultrastructure of these cells as seen with scanning and transmission electron microscopes is described. Bipolar cells display the same characteristics as those of migrating granule cells “in vivo”. Differentiation of these cells towards neuronal types becomes evident at the end of the first week “in vitro”. Axonal as well as dendritic growth cones were examined, and their ultrastructural characteristics described. Attention is focussed into the abundance of smooth endoplasmic reticulum, which in supposed active growth has the form of thin cisternae, and, at rest or in retraction takes the form of large vesicles. In the latter case, filopodia disappear, and the tips of their processes acquire a bulbous shape.
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    Cell & tissue research 146 (1973), S. 123-138 
    ISSN: 1432-0878
    Keywords: Leydig cells ; Testis ; Innervation ; Reptiles ; Electron microscopy ; Fluorescence microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the tortoise Testudo graeca, the lizards Lacerta dugesi and Lacerta pityusensis, and the snake Natrix natrix, the innervation of the testicular interstitial tissue was studied by light and electron microscopy, the acetylcholinesterase (ache) technique, the Falck-Hillarp method for the detection of catecholamines, and the application of 6-hydroxydopamine. The intertubular spaces of the reptilian testes studied contain adrenergic nerve fibers the amount and distribution of which varies considerably both in various species and in various stages of the reproduction cycle. Nerve fibers do not enter the seminiferous epithelium. Fluorescence microscopy of the lizard testis reveals catecholaminergic varicosities which are mainly arranged around blood vessels, but do not show obvious connexions to Leydig cells. Ache-positive fibers are equally distributed in lizard testes surrounding each seminiferous tubule. In Natrix natrix ache-positive fibers are irregularly spread among groups of tubules, without showing a definite relation to Leydig cells either. By electron microscopy bundles of unmyelinated axons and axon terminals can be more easily detected in the testes of immature animals than in adult. Terminals of nerve fibers containing small (400–500 Å in diameter) and large (800–1400 Å) dense-cored vesicles and sometimes small clear vesicles establish contacts with Leydig cells. Three types of contact are described. 1. “Contacts” par distance at a distance of about 2000 Å and basal lamina interposed; 2. membranous contacts having a 200 Å gap only between axolemma and Leydig cell plasmalemma; 3. invaginations of terminals into Leydig cell perikarya. The latter may exhibit surface specialisations, which strongly resemble postsynaptic membrane thickenings. Experiments using 6-hydroxydopamine underline the adrenergic character of testicular nerve fibers, which can be regarded as another example of non-cholinergic, ache-positive neurons. In the testis of the immature tortoise profiles of axons occur which probably represent purinergic, ache-positive neurons.
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  • 74
    ISSN: 1432-0878
    Keywords: RNA synthesis ; Spinal ganglia cell cultures ; Autoradiography
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    Notes: Summary Dissociated cells from 9, 12 and 15 day-old chick embryo spinal ganglia were cultivated in presence of total embryo-extract, brain embryo extract, or total embryo extract supplemented with purified nerve growth factor (NGF). The cells were maintained during 4 days in Maximow assembly and during 1 month in Rose chamber. Neurons showed growth of nerve fibres. The non-neural cells evolved to spindle cells, Schwann cells, or fibroblasts. Ribonucleic acid (RNA) synthesis was followed with tritiated uridine by autoradiography. Some nerve cells showed tritiated uridine incorporation. The highest incorporations for short-term cultures were at 15 hours in presence of NGF, at 48 hours in presence of total or brain extract, and for long-term cultures at 8 days. These periods corresponded to the highest growing activity of the nerve fibres. After 4 days all the non-neural cells incorporated tritiated uridine. The tritiated uridine was first incorporated into the RNA of the nucleus and, afterwards was found also in the cytoplasm. The presence of brain extract or of NGF stimulates the incorporation of labelled uridine into RNA. No labelling was found in the nerve fibres, even after 4 hours incubation.
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    Cell & tissue research 125 (1972), S. 415-431 
    ISSN: 1432-0878
    Keywords: Synapses ; Rat ; Cerebral cortex ; Glutaraldehyde/E-PTA ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary Synaptic junctions in intact rat cerebral cortex have been examined following glutaraldehyde fixation and phosphotungstic acid (PTA) staining. In the presynaptic ending the network has a hexagonal arrangement, while the dense projections are regularly placed along the presynaptic membrane. Cleft densities occupy the intracleft region. The postsynaptic thickening extends uninterrupted along the length of the junction. Qualitatively, the majority of junctions fall into the ‘discontinuous-continuous’ category, in which the internal coat of the presynaptic membrane together with its associated dense projections is discontinuous along the length of the junction, whereas the postsynaptic thickening is continuous. By contrast, a small number of junctions are ‘continuous-continuous’. In an attempt to analyze the junctions quantitatively, nine indices were measured. Histograms of the size distributions of seven of these appear to be bimodal, and from this it is concluded that two junction populations may be distinguishable on quantitative grounds. It is also shown that the distance separating dense projections at the presynaptic membrane is of the order of 10–15 nm. This surprisingly low value has consequences for current ideas on the relationship between synaptic vesicles and dense projections, and these are discussed at length.
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    Cell & tissue research 125 (1972), S. 432-447 
    ISSN: 1432-0878
    Keywords: Synaptosomes ; Synapses ; Rat ; Cerebral cortex ; Glutaraldehyde/E-PTA
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    Topics: Biology , Medicine
    Notes: Summary Working with glutaraldehyde fixed, PTA stained rat cerebral cortex, the authors compared the ultrastructural features of synaptosomes with those of intact synaptic junctions. In general there is close correspondence between the two, although the cleft densities and postsynaptic focal densities of synaptosomes show a greater degree of focalization than their counterparts in synaptic junctions. The dense projections have similar profiles in both preparations, but are more difficult to distinguish clearly in synaptosomes on account of the closer packing of the presynaptic network around their apices. The limiting membrane of the presynaptic terminal is usually visible in synaptosomes, but not in synaptic junctions. Comparing the preparations quantitatively reinforces the qualitative findings, and points to their overall similarity. However a number of the indices in synaptosomes are significantly smaller than the corresponding ones in synaptic junctions, and this points to the operation of a shrinkage factor during fractionation procedures. This is confined to the pre- and post-synaptic components and does not affect the intervening contact region. Histograms of the size distributions of the indices are similar to those obtained for intact synaptic junctions, the majority displaying two peaks. It is concluded that synaptosomes accurately reproduce the major ultrastructural features of synaptic junctions.
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    Cell & tissue research 144 (1973), S. 299-308 
    ISSN: 1432-0878
    Keywords: Shell glands ; Artemia salina ; White and brown glands ; Light and electron microscopy
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    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Ce travail concerne l'étude morphologique de la glande coquillière non pigmentée ou blanche d'Artemia salina. La structure de celle-ci est comparée à celle de la glande coquillière brune de la même espèce. Les différences sont apparemment plus fondamentales qu'une simple variation de la quantité de produit de sécrétion ou de la pigmentation des cellules. Là où les glandes coquillières brunes formeraient la coque chez les animaux ovipares les glandes coquillières blanches pourraient sécréter les produits nécessaires ou utiles au développement des nauplii chez les animaux ovovivipares.
    Notes: Summary The white shell glands of Artemia salina have been investigated. Our results, compared to those obtained in the brown-coloured shell glands, occuring within the same species, reveal differences not only in the aspect of the secretory granules but also in the structure of the nucleus and the cytoplasm. These differences between the two types of glands appear to be more striking than a simple variation in the quantity of secretion or in the pigmentation of the gland. As the brown glands are supposed to contribute to the formation of the egg shells in oviparous animals, the secretion of white glands could favour the development of nauplii in ovoviviparous animals.
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    Cell & tissue research 150 (1974), S. 143-145 
    ISSN: 1432-0878
    Keywords: Arteria centralis retinae ; Cat ; Innervation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Terminal axons emerging from the inner plexiform layer of the cat retina reach the wall of the arteria centralis retinae, as revealed by electron microscopy. Numerous unusually large dense core vesicles (about 1000 Å in diameter), of different electron densities, occur in the varicosities of these axons. These observations may be compatible with the idea of an innervation of the central artery of the retina which is non-autonomic, possibly intrinsic in nature.
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    Cell & tissue research 150 (1974), S. 443-454 
    ISSN: 1432-0878
    Keywords: Haematopoiesis ; Lymnaea stagnalis ; Amoebocytes ; Autoradiography ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to investigate haematopoiesis in the freshwater pulmonate Lymnaea stagnalis, the blood cells and the connective tissue of this snail were studied by light and electron microscopy as well as by autoradiography. In the circulating blood only one type of cell, the amoebocyte, is present. Amoebocytes also occur in the connective tissue (tissue amoebocytes) as single cells, in small groups or in large accumulations. Study of the morphology and ultrastructure of blood and tissue amoebocytes shows that no differences exist between these cells, indicating that L. stagnalis does not possess a well-defined haematopoietic organ. This assumption is supported by the following observations: 1. both blood and tissue amoebocytes can act as phagocytes, 2. blood and tissue amoebocytes both have the capacity to divide (i.e. incorporate tritiated thymidine) and 3. the percentage of dividing cells in the blood and in the connective tissue is the same. These quantitative data indicate furthermore that there is no difference in the relative importance of the blood and the connective tissue in the process of haematopoiesis. Comparison of tritiated thymidine labelled cells with unlabelled amoebocytes showed that these cells do not differ with respect to their morphology and ultrastructure. Moreover, amoebocytes involved in phagocytosis and encapsulation of foreign materials or in wound healing still have the capacity to divide. The percentages of tritiated thymidine labelled amoebocytes in different snails varied considerably. It is suggested that this variation reflects differences in the physiological state of the individual snails.
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    Cell & tissue research 150 (1974), S. 545-552 
    ISSN: 1432-0878
    Keywords: Skin, rat ; Cytology ; Innervation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary Neural elements within the parenchyma of the sebaceous gland have not been reported previously. Nerve endings have been observed only in the connective tissue surrounding the gland or in close association with the undifferentiated basal cells. In this study, electron microscopy revealed the possible presence of nerve endings (or terminal portions of neural elements) in the suprabasal level of functional sebaceous glands of pinnae of white rats. Morphologically, there are two distinct types of nerve endings. Type 1 is bordered by a membrane of relatively irregular contour and contains a single mitochondrion, various-sized vesicles, numerous microtubules, fine neurofilament-like fibrils, and occasional ribosome-like granules. Type II is also bordered by a membrane, but its contour was relatively smooth and rounded. Moreover, Type II contains many mitochondria, varying in size, density, and the arrangement of cristae. While ribosome-like granules are scattered throughout the structure in relative abundance, there are scarcely any fine neurofilament-like fibrils or microtubules. Whether these two structures are sensory or autonomic fibers could not be determined by electron microscopic examination.
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  • 81
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    Cell & tissue research 151 (1974), S. 509-523 
    ISSN: 1432-0878
    Keywords: Gill ; Trout ; Secondary lamellae ; Development ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A light and electron microscope study of secondary lamellae of trout developing at 10° C is described. Collagen is secreted by mesenchyme cells in the connective tissue of the developing gill filament. This becomes enclosed in infoldings around the peripheries of mesenchyme cells. These cells become aligned in a single plane within folds of basement membrane and epithelium. The basement membrane of opposite sides of the fold becomes connected by a thick layer of collagen. Blood spaces form around the margin of the fold, connecting afferent and efferent filament blood vessels. Endothelial granules form in cells lining the outer border of the marginal channel when blood flow begins. Rows of pillar cells separate from the proximal layer of mesenchyme cells as the secondary lamellae develops further. New secondary lamellae are added at the filament tips. At 28 days, the basement membrane consists of 2 layers, a fine fibrous layer and 5–15 orthogonally arranged layers of collagen fibres. By 31 days, the collagen is arranged at random and the layer is thinner. A clear layer is also present by 67 days. A multilayered epithelium containing mucous and chloride cells is present at 28 days. By 102 days, the secondary lamellae are covered by 2 layers of epithelial cells only. Chloride cells are present in much greater numbers in developing gills than in the adult.
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  • 82
    ISSN: 1432-0878
    Keywords: Synapses ; Embryo (Xenopus laevis) ; Spinal cord ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The rostro-caudal gradient of differentiation found in vertebrate embryos has been utilized to examine the sequence of synaptic junction development in the spinal cord of Xenopus laevis at a late embryonic stage. Uniform samples were taken at various points along the cord of a stage 27 embryo and examined in the electron microscope. The general ultrastructure of the cord demonstrated the rostro-caudal gradient of development. The sequence of synaptic junction development was like that in the cervical region (Hayes and Roberts, 1973). “Membrane-vesicle clusters” and “immature” synaptic junctions were found most caudally followed by synaptic junctions, first with cleft and subsynaptic membrane density, then with only cleft density and finally, most rostrally, with cleft, subsynaptic membrane, and subsynaptic cytoplasmic density. Mature synaptic junctions were found in increasing numbers from the mid to anterior trunk cord and could mediate alternating trunk flexions made by the embryos at this stage of development. “Membrane-vesicle clusters” were found near processes containing irregular vesicles and also near membrane outlines. These may be signs of dendritic growth. “Membrane-vesicle clusters” were also found in varicosities, facing the space around the spinal cord and in nerve fibres peripherally between the skin and myotomes. This suggests an association of early stages in synaptogenesis with axon growth. This and other possible inferences about axon and dendrite growth in relation to synaptogenesis are discussed.
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  • 83
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    Cell & tissue research 154 (1974), S. 443-470 
    ISSN: 1432-0878
    Keywords: Oocytes and T-prospermatogonia ; Rat ; Quantitative analysis ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Bei der Ratte findet die sexuelle Differenzierung der Gonade zwischen dem 14. und 15. Tag post conceptionem (p.c.) statt. Während dieser Zeit teilen sich die Oogonien und deren Parallelpopulation—die M-prospermatogonien (multiplying prospermatogonia) oder I-Gonocyten—sehr häufig. Um den 17. Tag p.c. tritt die letzte Generation der Oogonien bzw. der M-prospermatogonien in die Mitose. Die Mitosen bilden häufig “synchronisierte Gruppen”. Die postmitotischen Kerne ihrer Tochterzellen—der Oocyten und der T 1 prospermatogonien (primary transitional prospermatogonia) oder II-Gonocyten—sind klein. Ihr Chromatin ist in Form gröberer Schollen der Kernmembran angelagert. Auf diese Weise kommt das typische “krustenförmige” Aussehen bzw. die Ähnlichkeit mit den Prophasen der Oogonien und M-prospermatogonien zustande. Die Oocyten durchlaufen zunächst die G1-phase (etwa 10 Std Dauer) und treten dann—am Ende des Präleptotänstadiums—in die S-phase. Dann passieren sie die verschiedenen Stadien der meiotischen Prophase und treten vom 3. Tag post partum (p.p.) ab in das Dictyotänstadium. Die T1-prospermatogonien hingegen befinden sich etwa 10 Tage lang in der G1-phase, ohne wesentliche morphologische Veränderungen aufzuweisen. Vom 4. Tag p.p. an durchlaufen sie die S-Phase. Die S-Phasen-Dauer (D-S) beider Zellarten beträgt 11.5 Std und wurde durch Doppelmarkierung mit 14C- und 3H-Thymidin bestimmt. Als am besten geeignete Termine für die Bestimmung der D-S erwiesen sich bei den Oocyten der 18. Tag p.c. und bei den T1-prospermatogonien der 5. Tag p.p. Zu diesen beiden Zeitpunkten war die Anzahl der in die S-phase ein-und austretenden Oocyten bzw. T1-prospermatogonien gleich, die Zellen in S-phase befanden sich im “steady state”. Das Kernvolumen der Oogonien und M-prospermatogonien ist etwa doppelt so groß wie das der postmitotischen Oocyten und T1-prospermatogonien. Bis zum 5. Tage p.p. nimmt das Kernvolumen der Oocyten und T1-prospermatogonien um etwa das Fünffache zu. Der Degenerationsindex der Oocyten liegt wesentlich höher als der der T1-prospermatogonien; er ist postnatal besonders hoch. Aus den T1-prospermatogonien gehen am 4. und 5. Tage p.p. durch Teilung die T 2-prospermatogonien (secondary transitional prospermatogonia) hervor. Die Kerne dieses Zelltyps sind etwas kleiner also die der T1-prospermatogonien. Die T2-prospermatogonien treten am 6. Tage p.p. in die Mitose; es entstehen die ersten A-spermatogonien.
    Notes: Summary In the rat (Wistar-WU) sexual differentiation of the gonads occurs between days 14 and 15 post conception (p.c.). At this time the oogonia and their parallel population — the M-prospermatogonia (I-gonocytes)—divide rapidly. On about day 17 p.c., the last generation of oogonia and M-prospermatogonia, frequently arranged in synchronized clusters, enters mitosis. The postmitotic nuclei of their daughter cells—oocytes and T 1-prospermatogonia (II-gonocytes)—are small; coarse flakes of chromatin are associated with the nuclear membrane causing the typical “crustlike” appearance and the similarity with the prophases of oogonia and M-prospermatogonia. After the oocytes have passed a G1-phase of approximately 10 hr, they enter the S-phase at the end of the preleptotene stage. Then they pass the different stages of the meiotic prophase until they enter the dictyate stage from 3 day post partum (p.p.) onwards. The T1-prospermatogonia, on the other hand, spend a long G1-phase of about 10 days without any conspicuous morphological change before entering the S-phase from day 4 p.p. onwards. The duration of the S-pbase (D-S) of both cell types—oocytes and T1-prospermatogonia—as determined by the double labeling method with 14C- and 3H-thymidine is found to be 11.5 hr. The most favourable time for determining the D-S was day 18 p.c. for the oocytes and day 5 p.p. for the T1-prospermatogonia. On these two days the balance was reached between the cells entering and leaving the S-phase. The nuclear volumes of the postmitotic oocytes and T1-prospermatogonia are approximately half the size of those of their precursors. Until day 5 p.p. the nuclear volumes of the oocytes and T1-prospermatogonia increase about fivefold. The degeneration index of the oocytes is considerably higher than that of the T1-prospermatogonia; postnatally it is especially high. T 2 prospermatogonia arise by mitosis of the T1-prospermatogonia on day 4 and 5 p.p. The nuclei of this cell type are smaller than those of T1-prospermatogonia. T2-prospermatogonia enter mitosis on day 6 p.p and give rise to A-spermatogonia.
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    Cell & tissue research 155 (1974), S. 135-154 
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Frog ; Ultrastructure ; Intracellular transport ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The route by which secretory proteins are transported in the frog exocrine pancreas cell was investigated by an ultrastructural and electron microscope autoradiographic analysis of in vivo 3H-leucine labelled tissue. The ultrastructure of the cell is characteristic of serous epithelial cells and resembles that of mammalian exocrine pancreas cells very closely. Autoradiographic results revealed that the proteins, after being synthesized in the rough endoplasmic reticulum (RER), are transported through the Golgi cisternae to condensing vacuoles which subsequently change into secretory granules. The determination of the timing of this transport was complicated by a very slow turnover of leucine in the frog. Nevertheless, by a semi-quantitative approach, some time characteristics could be estimated: about 11 min after the onset of their synthesis the proteins enter the Golgi system, and about 25 min later the condensing vacuoles. Secretory granules become labelled between 60 and 120 min. These results are discussed, also in relation to the transport route and kinetics in mammalian tissue.
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  • 85
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    Keywords: Retinal projections ; (Tupaia glis) ; Axonal transport ; Synapse ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary Retinal projections were studied in the tree shrew, Tupaia glis, by means of thaw-mount autoradiography. In this technique, unfixed and unembedded frozen sections are directly mounted on photographic emulsion coated slides. Loss of radiolabeled material through tissue processing is avoided, probably resulting in increased discriminatory sensitivity. Together with multiple injections of precursor cocktail it is possible to demonstrate at the light microscopic level (1) fibers in passage and axon terminals simultaneously, and (2) preferentially labeled axon terminals in the projection field as areas of greater grain density.
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    Cell & tissue research 155 (1974), S. 449-453 
    ISSN: 1432-0878
    Keywords: Coronet cells ; Teleostei ; Neurohypophysis ; Hypersalinity ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary In several adult specimens of Mugil capito caught in a hypersaline lagoon, an intra-neurohypophyseal channel system lined with coronet cells has been observed. Coronet cells are normally found only in the saccus vasculosus, and in modern Teleostei, this structure is always completely separated from the neurohypophysis. The penetration of coronet cells into the neural lobe, may be an adaptive phenomenon possibly connected with an osmo-protective role of these cells.
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    Cell & tissue research 108 (1970), S. 446-456 
    ISSN: 1432-0878
    Keywords: Loligo vulgaris ; Innervation ; Dense core vesicles ; Helicoidal muscle ; Filaments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Innervation der braunen, roten und gelben Chromatophoren von Loligo vulgaris ist quantitativ und qualitativ verschieden. In den begleitenden Nervenbündeln finden sich stets Axone mit hellen (etwa 300 Å Ø), gelegentlich auch solche mit „dense-core“-Vesikeln (etwa 600 Å Ø). Die Myofilamente der kontraktilen Rinde sind gegeneinander versetzt und um die Längsachse spiralig gewunden. Im axialen Sarkoplasma treten gebündelte, in Längsrichtung zur Muskelzelle orientierte Filamente auf (jedes etwa 70 Å Ø), die möglicherweise eine Funktion bei der tonischen Kontraktion erfüllen.
    Notes: Summary The innervation of the brown, red and yellow chromatophore muscle cells in Loligo vulgaris shows quantitative and qualitative differences. The nerve bundles regularly contain axons with electronlucent vesicles of about 300 Å diameter, and occasionally axons with dense core vesicles of about 600 Å diameter. The myofibrils of the contractile cortex show a staggered arrangement and are wound in a spiral with respect to the axis of the muscle cell. In the axial sarcoplasm there is additionally a bundle of thin filaments of about 70 Å thickness. The bundle is orientated in parallel with the longitudinal axis of the muscle cell. Its function may be to maintain tonic contractions.
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    Cell & tissue research 109 (1970), S. 465-480 
    ISSN: 1432-0878
    Keywords: Cerebral artery ; Innervation ; Degeneration of sympathetic nerves ; Synaptic vesicles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the innervation of the anterior cerebral artery of the rat was studied in control animals and in animals after superior cervical ganglionectomy. Fluorescence histochemistry shows a periarterial network of intensely fluorescent fibers which are divided into two groups, adventitial and periadventitial. The fluorescence begins to decrease 26 hours after, and completely disappears about 32 hours after, ganglionectomy. Fine structural changes are first observed 18 hours after ganglionectomy, when the axoplasm of degenerating axons becomes electron dense. This density gradually increases up to about 32 hours. By 32 hours most axons with disintegrating axolemmas become inclusion bodies of the Schwann cells. At this stage, synaptic vesicles can still be distinguished as less dense areas, but the membrane structures of synaptic vesicles and mitochondria are difficult to recognize. The degenerating axons are gradually absorbed and by 38 hours dense, residual bodies are observed in the Schwann cells. Generally speaking, the degeneration occurs first in the adventitial fibers and then in the periadventitial fibers. The transient appearance of small, granular vesicles is noticed in axon terminals about 18 hours after denervation, although very few small, granular vesicles are seen in control tissue or at later stages of degeneration.
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    Cell & tissue research 110 (1970), S. 540-558 
    ISSN: 1432-0878
    Keywords: Cerebral cortex ; Synapses ; Rat ; Postnatal differentiation ; Morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of layers I and II of the motor cerebral cortex of rat brain has been studied at birth, 4, 7 and 14 days postnatal and in the adult. Compared with the adult, neonatal rat motor cortex exhibited a large extracellular space which decreases with increasing age. At all stages studied the neurons were seen to contain the organelles usually found in adult neurons. Growth cones were present in decreasing numbers up to 14 days old. Synapses were detectable at birth and there was an obvious increase in their number throughout the postnatal development. At the earliest stages studied there was a lack of specialization characteristic of the adult. Many synapses were either avesicular or relatively so and lacked the high degree of modification of adult pre- and postsynaptic membranes. By 7 days after birth many synapses existed which in all morphological respects resembled those of the adult, and by 14 days, the majority were of the adult type. These findings, particularly with reference to the postnatal development of synapses, have been discussed in relation to the known electrophysiological findings.
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    Cell & tissue research 112 (1971), S. 516-525 
    ISSN: 1432-0878
    Keywords: Glycogen body (birds) ; Lumbar spinal cord ; Aminergic neurons ; Innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Mit Versilberung und mit der fluoreszenzmikroskopischen Technik von Falck-Hillarp wurden im Glykogenkörper des Vogelrückenmarks Nervenfasern dargestellt. Diese Nervenfasern stammen aus Kerngebieten, die den Glykogenkörper flankieren. Die stärkste Fluoreszenz dieser lumbalen Kernareale findet sich an den beiden Polen des Glykogenkörpers. Es wird angenommen, daß das beschriebene aminerge Neuronensystem einen funktionellen Einfluß auf den Glykogenkörper ausübt. Der Glykogenkörper der Vögel wird mit anderen zentralnervösen Glykogendepots verglichen.
    Notes: Summary Nerve fibers were demonstrated in the glycogen body of the avian lumbar spinal cord by using silver-impregnation and fluorescence microscopic (Falck-Hillarp) techniques. These nerve fibers originated from nuclear areas in lateral juxtaposition with the glycogen body. The fluorescence of the nuclear area was strongest near the polar regions of the glycogen body. It was suggested that the aminergic neurons of the avian lumbar spinal cord may influence the glycogen body. The avian glycogen body was compared with other storage sites of glycogen within the central nervous system.
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    Cell & tissue research 114 (1971), S. 38-60 
    ISSN: 1432-0878
    Keywords: Pineal gland ; Cell types ; Synaptic ribbons ; Innervation ; Pregnancy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung In der Meerschweinchenzirbeldrüse lassen sich elektronenmikroskopisch „helle“ und „dunkle“ Pinealzellen sowie einzelne Gliazellen nachweisen. In den bei weitem überwiegenden „hellen“ Pinealzellen zeichnet sich ein Teil der „vesicle-crowned rodlets“ (VCR) durch lokale Auftreibungen aus. Von VCR deutlich abzugrenzen sind die „vesicle-crowned balls“ (VCB). Erstmalig beschrieben wird das Vorkommen von sog. Zylindern, die als Vorstufen von VCB aufgefaßt werden. In den relativ seltenen „dunklen“ Pinealzellen, die sich durch chromatinreiche Kerne und elektronendichtes Zytoplasma auszeichnen, sind Vesikel, VCR, VCB und „Zylinder“ seltener als in „hellen“ Pinealzellen. Die reichlich vorhandenen marklosen Nervenfasern finden sich vor allem in perivasculären Räumen, seltener im Parenchym. Synapsen zwischen Nerven und Pinealzellen wurden nicht beobachtet. In den Zirbeldrüsen trächtiger Meerschweinchen zeichnen sich in der 2. Hälfte der Tragzeit die „hellen“ Pinealzellen durch stärkere Lappung der Kerne, gehäuftes Auftreten von l“aktiven” Zonen, Vermehrung von Mitochondrien, glattem ER, agranulären Vesikeln, VCR, VCB und Zylindern aus. Die „dunklen“ Pinealzellen nehmen während der Tragzeit an Zahl zu. Post partum bilden sich diese Veränderungen innerhalb einer Woche zurück. Längerer Aufenthalt der Tiere in Dunkelheit führt zu einer Aktivierung der „hellen“ Pinealzellen mit auffallender Vermehrung der VCR und zu einer Zunahme der „dunklen“ Zellen. Unter Dauerbelichtung kommt es in den „hellen“ Zellen zu einer Abnahme fast aller Zellorganellen und zu einer starken Vermehrung der VCR, die nach 70 Tagen auch Formveränderungen aufweisen. Nach Reserpinbehandlung beobachtet man eine Verminderung und degenerative Veränderungen der VCR. Es wird diskutiert, daß die VCR als prae- bzw. postsynaptische Strukturen der Erregungsübertragung von Nerven zu Pinealzellen bzw. von Pinealzellen untereinander dienen könnten.
    Notes: Summary By means of electron microscopy “light” and “dark” pinealocytes can be distinguished in the guinea-pig pineal gland. Glial cells are rare. In the “light” pinealocyte. the most frequent cell type, some “vesicle-crowned rodlets” (VCR) show circumscribed thickenings. From these structures “vesicle-crowned balls” (VCB) have to be clearly distinguished. Furthermore “cylinders” occur, which, it is suggested, are precursors of VCB. “Dark” pinealocytes characterized by chromatin-rich nuclei and electron-dense cytoplasm are rare and contain fewer vesicles, VCR, VCB and “cylinders” than “light” pinealocytes. Numerous non-myelinated nerve fibres are situated within perivascular spaces, a few also in the parenchyma. Synapses between nerve fibres and pinealocytes were not observed. In the pineal gland of pregnant guinea-pigs the following changes can be observed in the second half of gestation. The “light” cells show many nuclear indentations and an increase of “active” zones, mitochondria, smooth ER, agranular vesicles, VCR, VCB, and “cylinders” respectively. The “dark” cells increase in number. After birth these changes reverse to normal within one week. Constant darkness leads to an activation of the “light” cells accompanied by an increase of the VCR and to an increase in number of the “dark” cells. Under constant illumination the “light” cells show a decrease of their organelles and a strong increase of the VCR. After 70 days the VCR also show a change in shape. Following reserpine treatment the VCR decrease in number and show signs of degeneration. It is discussed that the VCR function as pre- or postsynaptic structures and that they are involved either in transmitting impulses from nerve fibres to pinealocytes or from one pinealocyte to the other.
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    Cell & tissue research 115 (1971), S. 442-460 
    ISSN: 1432-0878
    Keywords: Regeneration ; Young Planarians ; ARN ; Actinomycin D ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé 1. Nous avons étudié les synthèses d'ARN pendant la régénération de jeunes Planaires à l'éclosion. Elles régénèrent dans l'eau ou dans l'actinomycine D à 50 μg/ml. Les synthèses sont décelées par l'incorporation d'uridine tritiée examinée en autoradiographie histologique et ultrastructurale. Des synthèses de protéines sont évaluées par incorporation de leucine tritiée. 2. La décapitation peu après éclosion entraîne, comme pour les adultes, un accroissement de la synthèse d'ARN. Celui-ci n'apparaît pas lorsque les animaux sont traités par l'actinomycine, et cependant, les jeunes commencent à régénérer. Le retour dans l'eau permet la reprise de l'incorporation chez les jeunes Planaires. Ce pouvoir de récupération varie suivant les individus. 3. L'actinomycine D n'a pas d'effet sur l'accroissement des synthèses de protéines chez les jeunes Planaires en régénération. 4. Le microscope électronique montre que l'incorporation d'uridine est inhibée par l'actinomycine dans toutes les catégories de cellules, quel que soit le degré d'altération cellulaire. La récupération du pouvoir d'incorporation de l'uridine qui se manifeste après le retour dans l'eau des jeunes décapités dépend de l'état d'altération primitif des structures. Les cellules aux nucléoles non dissociés, c'est le cas pour la majorité des cellules morphologiquement indifférenciées, retrouvent une structure normale et incorporent à nouveau activement l'uridine tritiée. Dans les cellules aux nucléoles dissociés qui sont surtout des cellules différenciées, il n'y a pas de reprise de l'incorporation d'uridine.
    Notes: Summary 1. We have studied RNA synthesis during regeneration of young hatched Planariang, Polycelis nigra. They regenerate in tap water or in actinomycin D 50 μg/ml. RNA synthesis is tested by histologic and ultrastructural examinations of radioactivity in tissues and cells incubated in tritiated uridine. Protein syntheses are tested after incorporation of tritiated leucine. 2. If decapitated a few days after hatching, young Planarians are characterized, as adults, by an increasing synthesis of RNA. This synthesis fails to increase if animals are incubated in actinomycin during a lapse of time of 24, 48 and 96 hours after cutting. However, the ability of young animals to regenerate is not impaired. If the young animals come back into water after 48 hours of inhibition in actinomycin, incorporation of uridine can start again, with some variations according to the importance of the blastema at the end of incubation in actinomycin. 3. Actinomycin D has no effect on the increase of protein synthesis in regenerating young animals. 4. Electron microscopy shows that uridine incorporation is inhibited by actinomycin D in every cellular category at any degree of alteration. Recovery, which appears after the return of the decapitated Planarians into the water, depends on the degree of cytological alterations. The cells with non dissociated nucleoli, that is the majority of the morphologically undifferentiated cells, assume again normal structures and can incorporate actively anew tritiated uridine. Cells the nucleoli of which are dissociated, mainly differentiated cells, do not resume uridine incorporation. We suppose, in conclusion, that in young growing Planarians cells, a mechanism exists which provides information for regeneration and cellular differentiation.
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    Cell & tissue research 115 (1971), S. 593-598 
    ISSN: 1432-0878
    Keywords: Polyamines ; Uptake ; Tetrahymena ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The uptake of the diamine 3H-putrescine by Tetrahymena pyriformis GL was studied in cultures which were synchronized by heat shocks. An inverse correlation was found between the uptake of putrescine and the acid stability of DNA, but there was also a parallelism between putrescine uptake and the intracellular amount of putrescine. There was no evidence for a transformation of the labeled putrescine to other amino compounds within the cells. Electronmicroscopical autoradiography showed a structure-bound radioactivity localized to nuclear and mitochondrial structures. In the nucleus, both the chromatin and the nucleoli showed labeling.
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    Cell & tissue research 114 (1971), S. 557-579 
    ISSN: 1432-0878
    Keywords: Retina ; Tissue Culture ; Synapses ; Retinal Rods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Netzhäute von 2–3 Tage alten Ratten wurden in Plasma auf Deckgläsern in Rollerröhrchen zur Kultur angesetzt. Nach 7–17 Tagen in vitro wurden die Kulturen mit Aldehyden und Osmiumsäure fixiert und für elektronenmikroskopische Untersuchung weiterverarbeitet. Gewebsquerschnitte (senkrecht zum Deckglas) zeigten histotypische Organisation, besonders in den dickeren Abschnitten der Explantate. Die Schichtung der Zellen entwickelte sich ganz ähnlich derjenigen in der Retina in situ aus dem relativ primitiven ausgepflanzten Netzhautepithel, jedoch enthielten die verschiedenen Schichten weniger Zellen als in der Retina in vivo. Alle Hauptnervenzelltypen konnten auf Grund ihrer Lokalisation und ihrer cytologischen Merkmale unterschieden werden. Die Entstehung von membranösen Lamellen in den Außengliedern der Sinneszellen konnte als Einfaltung der Plasmamembran beobachtet werden. Synaptische Bandkomplexe in ausgereifter Form wurden in der äußeren plexiformen Schicht nachgewiesen, während konventionelle Synapsen in der inneren plexiformen Schicht häufig angetroffen wurden. Synaptische Bänder waren ebenfalls in den Axonen bipolarer Zellen in der inneren plexiformen Schicht nachweisbar. Amakrine und Ganglienzellen waren in diesen Regionen ziemlich selten vertreten. Da die Untersuchung von nicht kultivierten Netzhäuten drei Tage alter Tiere keinerlei Synapsen zeigte, wird geschlossen, daß die Synapsen in den Kulturen in vitro entstanden sein müssen. Die Netzhaut stellt ein günstiges Modell für die Synaptogenese in vitro dar, indem sie verschiedene Vorzüge vor Explantaten aus anderen Regionen des Zentralnervensystems aufweist, nämlich eine klare Schichtung, zahlreiche identifizierbare Zellfortsätze mit charakteristischen synaptischen Beziehungen und eine wohl definierte Folge von Entwicklungsvorgängen.
    Notes: Summary Retinae from two- and three-day-old rats were explanted in plasma clots and grown in vitro with the flying coverslip method. After seven to seventeen days in culture, the retinal tissue was fixed with aldehydes and osmium tetroxide and embedded for examination with the electron microscope. Study of cross sections (perpendicular to the coverslip) revealed a histotypic pattern of organization, especially in the thicker regions of the explants. Layering of cells quite similar to that in the intact retina was seen to develop from the relatively primitive, explanted retinal epithelium. However, each layer contained fewer cells than its counterpart in vivo. All major neuronal cell types were distinguished by their location and cytological characteristics. Development of the saccules of sensory cell outer segments was observed to occur in vitro by an infolding of the plasma membrane. Synaptic ribbon complexes developed to the mature form in the outer plexiform layers, while conventional synapses were numerous in the inner plexiform layers. Synaptic ribbons were also seen in bipolar cell axons in the inner plexiform layers. Amacrine and ganglion cells in these regions were relatively sparse. A survey of posterior regions of noncultured three-day-old rat retinae showed no synapses of any sort; therefore the synapses in the cultures formed in vitro. The retina is recommended for studies of synaptogenesis in tissue culture, for it offers several advantages over expiants from other areas of the neuraxis, including a clear layering pattern, many identifiable cell processes with characteristic synaptic relationships between them, and a well-defined sequence of developmental events.
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  • 95
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    Cell & tissue research 115 (1971), S. 30-45 
    ISSN: 1432-0878
    Keywords: Adrenal Cortex ; ACTH ; Autoradiography ; Stereology ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The changes occurring in rat adrenocortical cells (zona fasciculata) during an 8 day period of treatment with ACTH, were investigated by morphometric and autoradiographic methods. The most important ultrastructural change consists in a conspicuous increase in the smooth endoplasmic reticulum, that accounts for about 50% of the total increase of cellular volume. Also the mitochondrial fraction shows a significant increase, which is found to be due both to the increment in the number of mitochondria per cell and to the increase in the mean volume of organelles themselves. The quantitative autoradiographic data, indicating an increment in the incorporation of 3H-orotate and 3H-leucine into adrenocortical cells of the treated animals, allow us to conclude that the ACTH-induced ultrastructural changes are the morphological expression of a stimulation of the cellular protein synthesis. Since mitochondria are largely autonomous in the synthesis of their enzymes and structural proteins, it is possible to hypothesize that ACTH also intervenes in the regulation of the mitochondrial protein synthesis.
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  • 96
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    Cell & tissue research 117 (1971), S. 118-138 
    ISSN: 1432-0878
    Keywords: RNA-synthesis ; Thyroxine ; Antibiotics ; Metamorphosis ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Frühwirkung von Thyroxin auf den RNS-Stoffwechsel in verschiedenen Geweben von Xenopus-Larven wurde autoradiographisch mit Uridin-3H untersucht. Bereits nach 4 h wird in Anwesenheit von Thyroxin (T4) eine Stimulation der nukleären RNS-Synthese festgestellt. Dabei sind das Ausmaß und der zeitliche Verlauf je nach Gewebe verschieden. Die RNS-Synthese wird nach einer T4-Vorbehandlung von 24 h am stärksten stimuliert. Während 72 h Hormon-Behandlung kann kein Transport markierter RNS vom Zellkern ins Cytoplasma festgestellt werden. Aetinomycin D hemmt die T4-induzierte RNS-Synthese bereits nach 4 h. Die stärkste Hemmung tritt nach 24stündiger Vorbehandlung auf. Puromycin hemmt die RNS-Synthese nur, wenn das Antibiotikum 24 h vor dem Hormon appliziert wird. Angesichts der starken Hemmung der RNS-Synthese durch Aetinomycin D wird angenommen, daß die T4-induzierten Veränderungen während der Metamorphose nicht nur durch Transkription spezifischer mRNS-Arten bedingt sind, sondern auch von der Bildung anderer RNS-Typen abhängen.
    Notes: Summary The early effects of thyroxine on RNA-metabolism in various tissues of Xenopus-larvae have been investigated by autoradiography using uridine-3H as precursor. In the presence of thyroxine (T4) a stimulation of nuclear RNA-synthesis is detected already 4 h after the onset of hormone administration. There are tissue-specific differences in the extent and the time course of response. T4 most effectively stimulates RNA-synthesis after 24 h of pretreatment. During 72 h of hormone treatment there is no detectable shift of labeled nuclear RNA into the cytoplasm. Actinomycin D inhibits T4-induced RNA-synthesis already after 4 h, but is most effective after 24 h of pretreatment. Puromycin inhibits RNA-synthesis to a minor extent, but only if exposure to the antibiotic precedes hormone administration. In view of the extent of inhibition of RNA-synthesis by actinomycin D, it is concluded that T4-induced metamorphic responses not only involves transcription of specific mRNA's, but must also depend upon formation of other types of RNA.
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  • 97
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    Cell & tissue research 115 (1971), S. 396-415 
    ISSN: 1432-0878
    Keywords: Human pineal organ ; Development ; Innervation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This investigation is concerned with pineal organs of human embryos 60 to 150 days old. At every stage central nerve fibres enter the pineal organ by way of the habenular commissure, but are restricted to the pineal's proximal part. On about the 60th day of the development the sympathetic nervus conarii grows into the distal pole of the pineal organ from a dorso-caudal direction and plays the predominant part in the innervation of the pineal organ. After penetrating, it soon branches out and forms a network in the pineal tissue. Much later, not until the 5th embryonic month, sympathetic nerves appear accompanying the supplying vessels in the perivascular spaces. After a short time these nerves pierce the outer limiting basement membrane and penetrate the parenchyma. Towards the end of the 5th embryonic month the axons of the sympathetic nerves form varicosities containing clear and dense core vesicles. At this point large amounts of laminated granules appear primarily in cell processes, probably of pinealocytes. Isolated granules also occur in the varicosities of axons. The granules encountered here are most likely secretory granules.
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  • 98
    ISSN: 1432-0878
    Keywords: Erythropoiesis ; Nucleated Red Cells ; Cell cycle ; Autoradiography ; Cytophotometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Um die Abhängigkeit der erythropoietischen Zellformen von ihrer Stellung im Generationszyklus (G1, S und G2) zu untersuchen, wurde das Knochenmark von vier Normalpersonen mit der Kombination von zytophotometrischer DNS-Bestimmung (Feulgen-Photometrie) und autoradiographischer Technik mit 3H-TdR (in vitro) untersucht. Die Zellen wurden vor dieser Untersuchung in den nach Pappenheim gefärbten Ausstrichen differenziert. Sowohl in der Gruppe der basophilen Erythroblasten (E1-E3) als auch bei den polychromatischen Normoblasten (E4) wurde eine postmitotische (G1) und eine prämitotische Ruhephase (G2) nachgewiesen. Beide Zellgruppen waren zu ca. 65% mit3H-TdR markiert (S). Unter den basophilen Erythroblasten war bei E1 eine G2-Phase, jedoch keine G1-Phase nachweisbar. Demgegenüber fand sich bei E3 eine ausgeprägte G1-Phase, hingegen keine G2-Phase. Bei E2 war sowohl eine G1-Phase als auch eine G2-Phase erkennbar. Nach diesen Befunden stellen die Erythroblasten E1-E3 keine Zellgruppen mit jeweils vollständigem Generationszyklus dar, sondern sind als ein Zellkompartment zu verstehen, in dem die G1-Phase vorwiegend durch die kleineren Zellen, die zytologisch die Merkmale der basophilen Normoblasten besitzen, und die G2-Phase vorwiegend durch die größeren Zellen vom Typ der Proerythroblasten und Makroblasten repräsentiert wird.
    Notes: Summary In the different types of normal human nucleated red cells the stages of the cell cycle (G1, S and G2) were investigated by combined application of the cytophotometric determination of the DNA content (Feulgen photometry) and of autoradiographic labelling using 3H-TdR in vitro. The individual cells were identified in Pappenheim stain. In the basophilic erythroblasts (E1-E3) as well as in the polychromatic erythroblasts (E4) about 62–65% of the cells were labelled (S). The unlabelled cells partly were diploid and partly were tetraploid, representing G1 and G2. The oxyphilic erythroblasts (E5) mostly were diploid and unlabelled (G1). Within the basophilic erythroblasts G1 was demonstrated mainly in E3, and G2 was demonstrated mainly in E1. In E2, G1 as well as G2 were present. The results indicate that all basophilic erythroblasts belong to one cell compartment, in which G1 is represented by the smaller cells commonly subclassified as basophilic normoblasts and G2 is represented by the large cells usually called proerythroblasts and macroblasts.
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  • 99
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    Cell & tissue research 119 (1971), S. 378-383 
    ISSN: 1432-0878
    Keywords: Seminal vesicles ; Rat ; Epithelium ; Proliferation activity ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung An 12 männlichen weißen Wistarratten unterschiedlichen Alters wurde autoradiographisch die Proliferation des Samenblasenepithels zur Zeit der Pubertät geprüft. Die Tiere waren 21, 29, 40, 50, 60 und 180 Tage alt und erhielten 1 Std vor der Tötung durch Dekapitation 2,5 μC 3H-Thymidin/g Körpergewicht i. p. appliziert. Ausgewertet wurden Autoradiogramme nach einer Expositionszeit von 18 Tagen; bestimmt wurde der Prozentsatz der markierten Zellkerne (3H-Index). Im Gegensatz zu dem bekannten exponentiellen Abfall des 3H-Indexes bei nicht-hormonabhängigen Leberepithelien jugendlicher Ratten kommt es beim Epithel der Samenblasen um den 40. Lebenstag zu einem erneuten, starken Proliferationsschub. Diese starke Wachstumszunahme ist wahrscheinlich der proliferationskinetische Ausdruck der nach Steinberger (1970) zur gleichen Zeit stattfindenden hormonellen Umschaltung in den Testes. Anschließend geht das Vermehrungswachstum des jugendlichen Tieres, durch das die Zellzahl erhöht wird, in das Erhaltungswachstum über; der 3H-Index des Samenblasenepithels erreicht den Wert des erwachsenen Tieres.
    Notes: Summary In 12 male white rats (Wistar) the proliferative activity of the epithelial cells in the seminal vesicles was studied by autoradiography. The animals were 21, 29, 40, 50, 60 and 180 days old. Each animal was given 2.5 μC/g 3H-thymidine and was killed 1 hour thereafter. We analysed the autoradiograms recording the percentage of labelled nuclei (3H-index). While the 3H-index of the non hormone-dependent epithelial cells in the liver of young rats declines continously with growing age (Stocker et al., 1964), the epithelial cells in the seminal vesicles of 40 days old rats show a remarkable rise in their proliferative activity. It is quite possible that this new peak in the proliferation is the morphological result of a preceeding switch in hormonal production of the testes as reported by Steinberger (1970). Thereafter the growth proliferation of the young rats declines into the steady state of the grown up.
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  • 100
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    Cell & tissue research 117 (1971), S. 354-380 
    ISSN: 1432-0878
    Keywords: Pineal complex ; Lampetra planeri ; Innervation ; Habenular ganglia ; Posterior commissure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Les connexions nerveuses des dérivés pariétaux de L. planeri avec l'épithalamus s'établissent ainsi: Le tractus pinéal (de plus de 600 axones nus) pénètre directement ou indirectement dans la commissure postérieure. La masse ganglionnaire (MG), sous-jacente à l'organe parapinéal, mérite d'être à nouveau considérée: soit comme une formation annexe de l'organe parapinéal (Tretjakoff), soit comme une division antérieure du ganglion habénulaire gauche (Studnička). Elle est en relation avec l'organe parapinéal par un court tractus et avec le ganglion habénulaire gauche (GHG) par une lame nerveuse (LN). Dans la MG, la LN et le GHG se rencontrent: 1. Des neurones typiques (rares dans la LN). 2. Des prolongements nerveux appartenant au moins à deux catégories de neurones: a) Axones de type 1, pauvres en granules de 1000 à 1300 Å. b) Axones de type 2, riches en granules de 900 à 2500 Å, rappelant des fibres neurosécrétrices. 3. Des synapses axo-dendritiques et peut-être (?) axo-axoniques. De l'ensemble de ces observations et de la discussion qui suit, nous considérons que la MG et la LN représentent la région antérieure du GHG. Néanmoins la MG et la LN peuvent contenir le tractus parapinéal. Le problème de l'incorporation de structures épithalamiques (en l'occurence d'éléments des ganglions habénulaires) à l'organe parapinéal et à l'organe pinéal d'autres animaux est envisagé dans le contexte phylétique.
    Notes: Summary Nervous (sensory) pathways of the pineal complex were studied in Lampetra planeri. The following observations were made: (1) The pineal tract, containing more than 600 unmyelinated fibres, connects directly or indirectly to the posterior commissure. (2) Connections of the nervous region (NR) adjoining the parapinéal organ (“ganglion parapinéales” of Tretjakoff or “division of the left habenular ganglion” of Studnička) have been re-examined; our study shows that the rostral division of NR is connected to the parapineal organ by a short tract and to the left habenular ganglion (LHG) by a nervous layer (NL). The NR, NL, and LHG contain the same following elements: (1) A collection of typical neurones (which are rare in the NL) in an abundant meshwork of nerve fibres. (2) At least two main types of axons: (a) Type 1 axons, containing few granules (1,000–1,300 Å diameter). (b) Type 2 axons, containing numerous granules (900–2,500 Å diameter), and resembling neurosecretory axons. Type 2 axons are not observed in the pineal and parapinéal organs. (3) Axo-dendritic and axo-axonic(?) synapses. Our study concludes that NR and NL represent the rostral part of LHG; nevertheless, NR and NL may contain the parapinéal tract. The problem of possible incorporation of epithalamic elements (e.g., elements of the habenular ganglia) into the parapinéal and pineal organs in other animals has been considered phylogenetically.
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