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  • Rat  (123)
  • Springer  (123)
  • American Chemical Society
  • 1970-1974  (123)
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  • Springer  (123)
  • American Chemical Society
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 10 (1972), S. 238-251 
    ISSN: 1432-0827
    Keywords: Growth ; Bone ; Rat ; Tetracycline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La vitesse de croissance normale en longueur de la métaphyse proximale du tibia est déterminée chez le rat Sprague-Dawley entre les âges de 20 et 100 jours, en utilisant la méthode à la tétracycline. Le taux de croissance ne varie que légèrement dans les groupes d'âges différents. Il est plus élevé chez les animaux jeunes et décroit considérablement en fonction de l'augmentation de l'âge. Les rats mâles présentent une croissance plus élevée que les femelles. Cette étude a pour but de mettre au point une méthode permettant de déterminer les facteurs expérimentaux, liés à la croissance en longueur du rat.
    Abstract: Zusammenfassung Die normale Längenwachstums-Geschwindigkeit der proximalen Wachstumsplatte der Tibia wurde bei Sprague-Dawley-Ratten in einem Alter zwischen 20 und 100 Tagen mittels der Tetracyclinmethode gemessen. Die Wachstumsgeschwindigkeit variierte nur wenig innerhalb der einzelnen Altersgruppen. Die Geschwindigkeit war bei jungen Tieren am höchsten und nahm mit zunehmendem Alter beträchtlich ab. Männliche Ratten wuchsen schneller als weibliche. Diese Arbeit dient als Grundlage, um die experimentelle Beeinflussung des Längenwachstums der Ratte abschätzen zu können.
    Notes: Abstract The rate of normal growth in length from the proximal growth plate of the tibia in the Sprague-Dawley rat was measured between 20 and 100 days of age using the tetracycline method. The growth rate varied only slightly within different age groups. The rate was highest in young animals and decreased considerably with increasing age. Male rats grew faster than female. This study is intended to provide a base for an evaluation of experimental influence on the growth in length of the rat.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 14 (1974), S. 283-289 
    ISSN: 1432-0827
    Keywords: Sodium fluoride ; Osteoporosis ; Bone ; Strength ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'utilisation thérapeutique de fluorure de sodium a été recommandée dans le traitement de diverses maladies osseuses ostéopéniques. Cet emploi est basé principalement sur les effects ostéosclérotiques bien connus du fluorure de sodium, mais on connait mal son effet sur la force de résistance osseuse. L'influence de diverses concentrations de fluorure de sodium sur la force de résistance osseuse de jeunes rats soumis à des régimes riches et pauvres en calcium a été étudiée. L'administration de fluorure de sodium augmente le diamètre osseux, indiquant une stimulation de la formation de l'os périosté, mais la force de résistance osseuse est réduite ou non modifiée par l'ingestion de fluor.
    Abstract: Zusammenfassung Die therapeutische Verwendung von Natriumfluorid ist für eine Anzahl von Knochenmangel-Krankheiten empfohlen worden. Die Empfehlungen basieren hauptsächlich auf den bekannten osteosklerotischen Wirkungen von Natriumfluorid; über dessen Effekt auf die Knochenstärke ist wenig bekannt. In dieser Arbeit wurde der Einfluß verschiedener Konzentrationen von Natriumfluorid auf die Knochenstärken von wachsenden Ratten mit hoher und niederer Calciumeinnahme untersucht. Die Verabreichung von Natriumfluorid erhöhte den Knochendurchmesser, was auf eine Stimulierung der Periostbildung hinwies, die Knochenstärke wurde jedoch durch Fluorideinnahme herabgesetzt oder nicht beeinflußt.
    Notes: Abstract The therapeutic use of sodium fluoride has been recommended in a variety of osteopenic bone diseases. The recommendations are based mainly on the known osteosclerotic effects of sodium fluoride and little information is available as to its effect on bone strength. The influence of various concentrations of sodium fluoride on bone strength in growing rats on high and low calcium diets was studied. The administration of sodium fluoride increased bone diameter, indicating stimulation of periosteal bone formation, but bone strength was reduced or not affected by fluoride ingestion.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 13 (1973), S. 113-129 
    ISSN: 1432-0827
    Keywords: Kinetics ; Growth ; Epiphyses ; Hypophysectomy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La largeur de la métaphyse tibiale, la zone indifférenciée, la zone sériée et les cellules en dégénerescence ont été observées chez des rats Sprague-Dawley normaux et hypophysectomisés. La production cellulaire de la métaphyse est déterminée sur la base de la croissance osseuse longitudinale déterminée par l'oxytétracycline et la taille des cellules en dégénérescence. La diminution de la croissance osseuse longitudinale, en fonction de l'augmentation de l'âge et après hypophysectomie, est due partiellement, à la diminution de production cellulaire et partiellement à une décroissance de la taille des cellules en dégénérescence dans la métaphyse. L'influence de la production cellulaire et de l'activité mitotique prédomine.
    Abstract: Zusammenfassung Die Breite der proximalen Wachstumsplatte der Tibia, deren undifferenzierter und säulenförmiger Zone und die Größe der nahe bei der Metaphyse auftretenden degenerativen Zellen wurden in normalen und hypophysektomierten Sprague-Dawley-Ratten bestimmt. Die Zellproduktion in der Wachstumsplatte wurde aus dem longitudinalen Knochenwachstum berechnet, welches mittels Oxytetracyclin und der Größe der degenerativen Zellen bestimmt wurde. Es wurde festgestellt, daß die Abnahme des longitudinalen Knochenwachstums bei zunehmendem Alter und nach Hypophysektomie zum Teil einem Rückgang in der Zellproduktion, zum Teil einer Verminderung der Größe der degenerativen Zellen in der Wachstumsplatte zuzuschreiben ist. Der Einfluß der Zellproduktion, und somit der mitotischen Aktivität, herrscht vor.
    Notes: Abstract The width of the proximal growth plate of the tibia, its undifferentiated and columnar zone and the size of the degenerative cell close to the metaphysis, were determined in normal and hypophysectomized Sprague-Dawley rats. The cell production in the growth plate was calculated from the longitudinal bone growth determined with oxytetracycline and the degenerative cell size. It was found that the decrease in longitudinal bone growth with increasing age and after hypophysectomy, is due partly to a decrease in cell production, and partly to a decrease in degenerative cell size in the growth plate. The influence of cell production and thus the mitotic activity predominates.
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  • 4
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    Cell & tissue research 110 (1970), S. 97-107 
    ISSN: 1432-0878
    Keywords: Muscle Spindles ; Different types of sensory endings ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung In einer Muskelspindel der Ratte, die an einer Serie alternierender Semidünn- und Ultradünnquerschnitte untersucht wurde, wurden zwei benachbart an „nuclear chain“-Fasern gelegene Nervenendformationen unterschiedlicher Bauweise festgestellt. Die beiden Endformationen sind mit ein und derselben Nervenfaser der Gruppe II verbunden und daher als Bestandteile einer sekundären sensorischen Endigung zu betrachten. Die Nervenendformation an einer der beiden „nuclear chain“-Fasern hat anulo-spirale Form. Die Nervenendformation an der anderen „nuclear chain“-Faser weist am Querschnittsbild eine Anzahl von Axonen auf, die zwischen Plasmalemm und Basalmembran der intrafusalen Muskelfaser eng aneinanderliegen. Nicht alle Axonquerschnitte stehen in direktem Kontakt mit der intrafusalen Faser. Das terminale Axon scheint sieh nach Eintritt unter die Basalmembran der intrafusalen Faser mehrfach in relativ dünne Äste unregelmäßigen Verlaufs zu teilen. Diese Form der Endigung könnte ein Korrelat der sog. „flower spray“-Endigung im Sinne Ruffinis (1898) darstellen. Die beiden morphologisch unterschiedlichen Endformationen innerhalb der sekundären Endigung gleichen einander und den Endformationen der primären Endigung bezüglich folgender Ultrastrukturmerkmale: 1. Es besteht synaptischer Kontakt zwischen Axon und intrafusaler Muskelfaser (synaptischer Spalt durchschnittlich 200 Å) ohne Zwischenlagerung von Basalmembranmaterial; 2. die terminalen Axonabschnitte liegen direkt unter der Basalmembran der intrafusalen Muskelfaser und sind nicht von Schwannschen Zellen bedeckt; 3. Mangel an synaptischen Bläschen; 4. desmosomenartige Verhaftungen zwischen Zellmembranen von Axon und intrafusaler Faser; 5. dyadenartige Anlagerungen des sarkoplasmatischen Retikulums an die Zellmembran der intrafusalen Faser im Bereich des synaptischen Spaltes. Nach unseren derzeitigen Vorstellungen sprechen diese Ultrastrukturmerkmale für eine rezeptorische Natur der beschriebenen Nervenendigungen.
    Notes: Summary In a rat muscle spindle transversally cut into a series of alternating semithin and ultrathin sections, two different forms of nerve terminations were found on two neighbouring nuclear chain fibres. The two nerve terminations were connected to the same group II nerve fibre and are consequently constituents of one particular secondary sensory ending. The nerve termination on one of the two nuclear chain fibres is of the anulo-spiral type. The nerve termination on the second nuclear chain fibre shows a number of axons lying closely together between plasma membrane and basement membrane of the intrafusal muscle fibre. Not all of these axons are in direct contact with the intrafusal fibre. The terminating nerve fibre seems to be divided into several branches of rather small diameters and irregular courses. It is suggested that this kind of termination could be a correlate of the so-called “flower spray” type of sensory endings in muscle spindles. The two morphologically different nerve terminations in the secondary ending have the following ultrastructural characteristics in common with those of the primary ending: 1) Synaptic contact between axon and intrafusal muscle fibre (synaptic gap about 200 Å) without interposition of basement membrane material; 2) terminal axons located beneath the basement membrane layer of intrafusal muscle fibres without covering by Schwann cells; 3) lack of synaptic vesicles; 4) desmosome-like structures between plasma membranes of axon and intrafusal muscle fibre, and 5) dyads of the sarcoplasmic reticulum adjacent to the synaptic cleft. According to present knowledge these features indicate that all of these endings are sensory ones.
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  • 5
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    Springer
    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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  • 6
    ISSN: 1432-0878
    Keywords: Adrenergic neurons ; “Short” and “long” systems ; Pre- and postnatal development ; Peripheral organs ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The adrenergic innervation in the submaxillary gland, heart, kidney, small intestine, and accessory male genital organs and the development of the adrenal chromaffin cells and the sympathetic ganglia were studied in the rat from 15 days post coitum to 16 days post partum using the fluorescence histochemical method of Falck and Hillarp. The postnatal development of the noradrenaline concentrations in the heart and vas deferens was followed by fluorometric determinations. At about 15 days post coitum, the anlagen of the sympathetic chains were well visible in the form of two dorsal segmented columns of small branching sympathicoblasts exhibiting an intense catecholamine fluorescence. In the midline, ventrally to these two anlagen, another column of sympathicoblasts developed; this seemed to give rise to the prevertebral ganglia and to the short adrenergic neurons supplying the internal genital organs. At the level of the adrenal anlagen, small intensely fluorescent chromaffin cells were collected in two bilateral groups which became enclosed by adreno-cortical cells. This enclosure was, however, not complete even at two weeks post partum. Bundles of growing sympathetic nerves were visible in the periphery of the various organs studied at 19–21 days post coitum. A terminal innervation of the organs suggestive of a functional transmitter mechanism did not start to establish until at or immediately after birth. The final pattern of innervation was usually reached at about one week post partum, and the following development proceeded largely in the form of a quantitative increase in the number of nerves participating in the innervation apparatus. The adult level of noradrenaline in the heart and vas deferens was reached three to five weeks after birth. The small intestine was an exception in that the final pattern of innervation in the wall was attained immediately after birth. There was no overt difference in the rate of development of the terminal sympathetic innervation in organs supplied by short adrenergic neurons (accessory male genital organs) compared to the innervation of the submaxillary gland, heart and kidney, which receive classical long adrenergic neurons.
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  • 7
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    Cell & tissue research 119 (1971), S. 58-67 
    ISSN: 1432-0878
    Keywords: Ovary ; Rat ; Fowl ; Granulosa cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The granulosa cells of the ovarian follicle of the rat and the domestic fowl have been studied with the light and electron microscope. The nuclei of the granulosa cells were irregular with indentations and large in proportion to the cytoplasm of the cell. The mitochondria had a dense, dark matrix with only few cristac. The Golgi apparatus was moderately developed, located towards the oocyte in a juxtanuclear position. The endoplasmic reticulum was rather sparse. Lipid droplets were only occasionally encountered. Microtubules were regularly observed. The functions of the granulosa cells are discussed. Compared with the steroid-producing cells of the theca interna of the same follicles, the granulosa cells primarily are the nursing cells for the growing oocyte and mainly have the characteristics of protein forming cells.
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  • 8
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    Cell & tissue research 122 (1971), S. 283-300 
    ISSN: 1432-0878
    Keywords: Paraventricular nucleus ; Rat ; Synthesis of hormones ; Acid phosphatase ; Osmium impregnation ; Neurosecretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural features of the paraventricular neurones of the non-treated rat are presented comparing them with those of the supraoptic neurones. No striking differences are seen between the general electron microscopic characteristics of the paraventricular and supraoptic neurones. The importance of adequate fixation to obtain good preservation of the neurones is emphasized, since inadequate fixation can cause e.g. artefactual appearance of “dark neurones”. The previously presented classification of the neurosecretory neurones into two categories (e.g. “light and dark neurones”) on the basis of the number of ribosomes is not considered justifiable, since their number can vary to a very great extent even within a single cell. The synthesis of neurosecretory products in the paraventricular neurones obviously follows the general mode of the synthesis of secretory proteins: ribosomes—RER—Golgi complex—secretory vesicles. On the basis of the localization of heavy metal deposits after osmium impregnation and demonstration of acid phosphatase the Golgi complex of the paraventricular neurones is found to be polarized. The direction of the polarity is discussed. The substructures of the dense cores of the neurosecretory granules and of the contents of the lysosomal dense bodies are nearly identical. Therefore it is considered impossible to determine positively the nature of the dark condensed material within the Golgi complex. The characteristics of the immature neurosecretory granules and the possibility of releasing neurosecretory products into the cytoplasm already within the perikarya are speculated.
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  • 9
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Two-filament system ; Small intestine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of glycerinated smooth muscle from small intestine of adult rat was investigated by electron microscopy. In the central parts of the tissue blocks a two-filament system was found, consisting of parallel thick and thin filaments with regularly spaced interconnections, closely resembling that of striated muscle. In the peripheral parts of the blocks only thin filaments were found. The thin filaments were identified as actin by the formation of arrowhead complexes after incubation with heavy meromyosin.
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  • 10
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    Cell & tissue research 121 (1971), S. 531-547 
    ISSN: 1432-0878
    Keywords: Helical polyribosomes ; Skeletal muscle ; Polysomes ; Levator ani ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The localization and configurations of ribosomes in mature white skeletal muscle fibers of the rat were investigated. Differential visualization of ribosomes and glycogen granules was obtained by fixation with glutaraldehyde only and staining of the sections with uranyl acetate. Ribosomes are then electron dense and glycogen granules electron transparent. Their identity was ascertained by selective extractions of ribonucleic acid and polysaccharide. The vast majority of the ribosomes is not membrane-bound. They are located intermyofibrillarly (predominantly at the level of the I-bands), beneath the sarcolemma, and in the paranuclear cones of sarcoplasm. Occasionally short stretches of granular reticulum occur, often as characteristic double walled vesicles with ribosomes on the inner membrane only. Three main types of polysomal configurations are observed: rosettes of 4 to 6 ribosomes, helical arrays, and whorls of up to about 25 probably membrane-bound ribosomes. The average number of ribosomes in the extended helical configurations is estimated to be about 60. It is argued that these helices represent the polysomes instrumental in the synthesis of the large subunits of myosin. It is emphasized that helical polyribosomes are by no means typical of striated muscle, but probably represent a common configuration of large free polysomes.
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  • 11
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    Cell & tissue research 126 (1972), S. 261-277 
    ISSN: 1432-0878
    Keywords: Adrenal medulla ; Rat ; Cell types ; Secretion ; Influence of fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Das Nebennierenmark der Ratte wurde nach Anwendung verschiedener Fixationsmethoden untersucht. Nach Immersionsfixation mit Glutaraldehyd oder Osmiumtetroxyd finden sich in der Nebenniere sog. Mischzellen, helle Zellen, syncytiale oder plasmodiale Zellen, die von den Untersuchern als Artefaktbildungen angesehen werden. In allen Proben nach Perfusionsfixation wurden solche Artefaktbildungen niemals beobachtet. Bei Immersionsfixation wurde eine enge Beziehung zwischen Sekretgranula und Cytoplasmamembran beobachtet, was bei Perfusionsfixation selten der Fall war. Die heutigen Theorien über den Sekretionsmechanismus bei Nebennierenmarkzellen werden aufgrund der vorgelegten Ergebnisse diskutiert. Die Arbeit zeigt die wesentlichen Vorteile der Anwendung der Perfusionsfixation für die Untersuchung der Nebenniere.
    Notes: Summary The adrenal medulla of the rat was studied utilizing various methods of fixation. In adrenal medulla specimens after immersion fixation either with glutaraldehyde or osmium tetroxide, elements such as mixed, clear, syncytial, or plasmodial cells, believed to be of artifactual origin, are observed in all of this material examined. These elements are absent in the specimens prepared by perfusion fixation. In specimens prepared by immersion fixation, secretory granules are found in close proximity to the plasma membrane; this localization is infrequent after perfusion fixation. Current theories of the mechanism of secretion of adrenal medullary hormones are discussed on the basis of our results. This investigation demonstrates the advantage and necessity of perfusion fixation in the study of the adrenal medulla.
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  • 12
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    Cell & tissue research 126 (1972), S. 466-482 
    ISSN: 1432-0878
    Keywords: Macrophages ; Microtubules ; Enamel organ ; Rat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the enamel organ of rat incisors macrophages are present in the zone of matrix formation, the transitional zone, the enamel maturation and pigmentation zone. The macrophages accumulate adjacent to redifferentiating amelocytes in the transitional zone. The macrophages phagocytize fragments of disintegrating amelocytes. In addition to the well known complement of organelles the macrophages present an elaborated microtubular system, scattered, thick filaments, a cortical feltwork of thin filaments, and spherical nuclear bodies. The microtubules emanate from “attached” and free pericentriolar satellites and radiate aster-like towards the cell surface or into pseudopods or curve along the nuclear surface for long distances, often related to nuclear constrictions. It is suggested that the microtubular system plays a prominent role in directional movement of the macrophages. The cortical filaments, if contractile, may create the cytoplasmic flow necessary for the cell motility.
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  • 13
    ISSN: 1432-0878
    Keywords: Olfactory tubercle ; Rat ; Degeneration ; Synapse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The olfactory tubercle of the rat was studied by electron microscopy both in the normal and after ipsilateral olfactory bulb ablation at survival times of from 14 hours to seven days. Particular emphasis was placed on synaptic structures and their changes following the lesion. Normal synapses are similar to those described in previous studies and presynaptic profiles are of at least three types. Types-A and -B contain round vesicles and form asymmetrical contacts and type-C profiles contain flattened vesicles and form symmetrical contacts. There appear to be two major types of degenerative changes. The electron-lucent type predominates at early survival times and is seen first at 14 hours. These profiles show an early reduction in numbers of vesicles with mitochondrial swelling followed by shrinkage of the profile. These profiles become increasingly electron-dense at later survival times. The second major type of degenerating profile is initially electron-dense. The earliest changes in these profiles are an increased axoplasmic density and increased microtubular density and clumping without apparent loss of vesicles. These profiles also become progressively more electron-dense at longer survival times. The observations are discussed in relation to previous reports.
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  • 14
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    Cell & tissue research 127 (1972), S. 201-208 
    ISSN: 1432-0878
    Keywords: Spermatogenesis ; Rat ; Mitosis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pattern of intercellular cytoplasmic bridges between rat spermatogonia and between spermatocytes is illustrated from electron microscopy of serial sections. Clones, or syncytia, containing as many as 22 connected spermatogonia and as many as 74 connected spermatocytes were observed. The absence of closed rings of cells agrees with the observation that intercellular bridges are the result of incomplete cell division, rather than cell fusion. The bridges thus are a record of spermatogonial divisions within a clone. In early spermatogonial generations there is a predominantly linear arrangement. The groups of spermatocytes have more side branches. From the presence of synaptonemal complexes it is concluded that the connected spermatocytes of a given clone are in about the same developmental stage. The pattern of intercellular bridges indicates, however, that not all nuclei in a clone undergo mitosis in the same cycle. The connected cells of a clone are therefore not all of the same generation. From unconnected bridges it is assumed that new clones originate from single cells or groups of spermatogonia which separate from an existing clone.
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  • 15
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    Cell & tissue research 130 (1972), S. 171-179 
    ISSN: 1432-0878
    Keywords: Tubuli seminiferi ; Rat ; Structure ; Contractility ; Organ culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Isolated pieces of seminiferous tubules of adult rats were grown in organ culture for up to 8 weeks in Petri dishes on the surface of nutrient agar. The medium consisted of newborn calf serum, Eagle's minimum essential medium, glutamate and antibiotics. This method allowed observation of the contractions of the seminiferous tubules in the culture. Contractility, light and electron microscopic structure and histochemically demonstrable activities of alkaline phosphatase and ATPase of the tubule walls were studied at 1-week intervals. The contractility and alkaline phosphatase activity were maintained in the tubule wall for 3 weeks, and the activity of ATPase was maintained for 5 weeks. The thin filaments of the myoid cells, which are responsible for the contractility, were seen with the electron microscope in tubules cultured for 5 weeks. The organ culture method described in the present paper seems to be valuable for studies concerning the functioning of the myoid cells of the seminiferous tubules and the possibility that this is regulated by hormones.
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  • 16
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    Cell & tissue research 131 (1972), S. 99-107 
    ISSN: 1432-0878
    Keywords: Median eminence ; Rat ; Exocytosis ; Micro-pinocytosis ; Releasing factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Exocytosis has been demonstrated by electron microscopy in the external zone of the median eminence of the rat. Exocytotic profiles have been observed in nerve fibres characterized by the presence of granular vesicles with median diameters of 90–103 nm and agranular vesicles of about 50 nm. In addition to the small agranular vesicles, coated vesicles of the same size have been found in many nerve fibres, suggesting that at least part of the agranular vesicles in the median eminence originate by micro-pinocytosis. The nature of the fibres showing exocytosis is discussed. Attention is drawn to the possibility of identifying types of fibres in the median eminence by the occurrence of exocytosis.
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  • 17
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    Cell & tissue research 132 (1972), S. 553-562 
    ISSN: 1432-0878
    Keywords: Basement membrane ; Brain ventricles ; Rat ; Subependymal labyrinths ; Light- and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Mit der Perjodsäure-Bisulfit-Aldehydthionin-Färbung (Specht) lassen sich am ganzen Ventrikelsystem des Rattengehirns sub- und interependymale Strukturen lichtmikroskopisch nachweisen, die elektronenmikroskopisch als Basalmembranlabyrinthe (BML) identifiziert werden können. Verschiedene Formen dieser BML lassen sich unterscheiden. Sie stehen in Verbindung mit subependymalen Kapillaren. Die Verteilung der BML wird in Ventrikelkarten dokumentiert.
    Notes: Summary Sub- und interependymal structures, being demonstrable by a period-acid-bisulfit-aldehydthionine-method (Specht), occur in the whole ventricular system by light microscopy. They can be identified electron microscopically as basement membrane labyrinths (BML). Different shapes of these BML can be distinguished. They are in communication with the basement membrane of subependymal capillaries. The distribution of BML is documented in “ventricular maps”.
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  • 18
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    Cell & tissue research 134 (1972), S. 205-225 
    ISSN: 1432-0878
    Keywords: Diabetes insipidus ; Rat ; Hypothalamo-neurohypophysial system ; Synthesis of hormones ; Light- and Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The general ultrastructural features of the hypothalamo-neurohypophysial system in rats with hereditary hypothalamic diabetes insipidus (DI-rats, Brattleboro strain) are described. There is no decisively distinguishing difference between the neurons of the supraoptic and paraventricular nuclei. The neurons of both nuclei show signs of active protein synthesis. The perikarya of the neurons are markedly hypertrophic, the nuclei are large and the nucleoli prominent. In the cytoplasm there are numerous ribosomes, abundant rough-surfaced endoplasmic reticulum and extensive Golgi complexes. However, very few neurosecretory granules are to be seen. The axons of the hypothalamo-neurohypophysial tract are likewise enlarged and the paucity of neurosecretory granules is a striking feature also in the area of the tract. The majority of nerve endings in the posterior pituitary of DI-rats are devoid of neurosecretory granules. Microvesicles are abundant in the nerve endings and there are findings which suggest that microvesicles are involved either in endoor exocytosis. The signs of active protein synthesis and the concomitant paucity of neurosecretory granules are interpreted to imply transportation of the secretory proteins in an extragranular phase. The possible mode of release of the secretory proteins from the nerve endings and the role of microvesicles therein are discussed.
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  • 19
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    Cell & tissue research 132 (1972), S. 25-34 
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Rat ; Perivascular cells ; Neurosecretion ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The purpose of this study is to investigate the ultrastructural features of perivascular cells as found in the neural lobe of the hypophysis. In particular, an inquiry was made into the nature of the relationship of such cells to neurosecretory fibers and endings. The latter, in fact, are often invaginated within the perivascular cells and enveloped by their processes; furthermore, they often reveal a certain number of empty granules as well as characteristics of degenerative nature. In the course of this study the localization of the perivascular cells has been investigated as well as that of their processes within the extensive interlobular network typical of the hypophysial neural lobe of rodents. Based on the data gathered, the hypothesis is put forward that the perivascular cells play an important role in the turnover of neurosecretory endings, both under physiological and experimental conditions, contributing thereby to the release of post-hypophysial hormones.
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  • 20
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    Cell & tissue research 139 (1973), S. 101-148 
    ISSN: 1432-0878
    Keywords: Infundibulum ; Rat ; Neuro-glial synapses ; Neuro-Vascular contacts ; Corticotropin-Releasing Factor ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung 1. Die Gefäßfortsätze von ependymalen und subependymalen Zellen bilden in der subependymalen Zone und in der Zona interna des Ratteninfundibulum mit Nervenfasern kompakte neuro-gliöse Faserbündel, die sich in der Zona externa aufzweigen. 2. In allen Zonen des Infundibulum kommen zwischen den Nervenfasern und den Gefäßfortsätzen zahlreiche neuro-gliöse Synapsen vor. In den Gefäßfortsätzen fällt die hohe Zahl an Mikrotubuli sowie die zahlreichen, vielgestaltigen Einschlüsse auf. 3. In der subependymalen Zone sind die Interzellularspalten an bestimmten Stellen außerordentlich weit. Sie haben eine kanalartige Beschaffenheit und enthalten feine Bündel von Nervenfasern. 4. Von den lateralen Anteilen des Infundibulum her erreichen Dendriten von Ganglienzellen des Nucleus infundibularis die Mitte des Infundibulum. In dieser Region sind axodendritische Synapsen anzutreffen. 5. Morphometrische Analysen der Nervenfaserendigungen der Zona externa von Normaltieren zeigen, daß die prozentuale Verteilung der nach Granulagröße differenzierten Nervenfaserklassen für Mitte und Seite der Zona externa etwa gleich ist. Zwischen der Größe der Elementargranula und der Anschnittfläche der zugehörigen Nervenfasern besteht eine direkte Beziehung. 6. Die Nervenfaserendigungen erreichen die Basalmembran des perikapillären Raumes fast ausschließlich im Bereich von gefäßwärts gerichteten Vorwölbungen der Zona externa. Das Ausmaß, in dem Nervenfasern im Vergleich zu den Gefäßfortsätzen von Ependymund Gliazellen den perivaskulären Raum erreichen, ist medial weitaus größer als lateral. 7. Bei bilateral adrenalektomierten Ratten nimmt in bestimmten, vorwiegend lateral gelegenen Nervenfasern die Zahl und Größe der Elementargranula in Abhängigkeit von der Überlebensdauer zu. Dies dürfte auf eine verstärkte Synthese und Speicherung von Corticotropin-Releasing Factor in diesen Nervenfasern zurückzuführen sein. Gegenüber dem Normalbefund ist die neurohämale Kontaktfläche erheblich vergrößert. Der perivaskuläre Raum enthält zerfallene Nervenfaserteile, die durch Bindegewebszellen phagocytiert werden. Diese Veränderungen dürften durch eine unter Versuchsbedingungen verstärkte Wachstumstendenz der Nervenfasern in Richtung auf die Blutgefäße und durch eine Abschnürung der Nerven-faserendigungen ausgelöst werden.
    Notes: Summary 1. In the subependymal and internal zones of the rat median eminence nerve fibres and vascular processes of ependymal and subependymal cells form neuro-glial bundles. They branch in the external zone. 2. In all these three zones of the infundibulum numerous neuro-glial synapses are found between nerve fibres and vascular processes of glial cells. The vascular processes contain a high number of microtubules as well as polymorphous granular inclusions. 3. In certain regions of the subependymal layer the intercellular spaces are enlarged. They form channel-like spaces containing small bundles of delicate nerve fibres. 4. Nerve cells of the infundibular nucleus located in the lateral parts of the infundibulum send dendrites to the medial parts of the infundibulum. In this area axo-dendritic synapses are found. 5. For morphometric analysis, the nerve fibres of the external zone were classified according to the diameter of their granules. It is shown that in the different regions of the external zone the distribution of the various types of nerve fibre is similar. Moreover it can be seen that a direct correlation exists between the size of the sectional plane of a given nerve fibre and the size of the granules it comprises. 6. Nerve fibre endings abutting on the basement membrane of the pericapillary space are mostly found in bulb-like protrusions of the external zone. The extent to which nerve fibres reach the perivascular space—as compared with the vascular processes of ependymal and glial cells—is higher in the medial than in the lateral parts of the infundibulum. 7. In bilaterally adrenalectomized rats the number and diameter of elementary granules increases in nerve fibres located laterally. This increase is directly related to the survival time and may be due to an enhanced synthesis and storage of Corticotropin-Releasing Factor in these nerve fibres. Compared with the findings in untreated animals the neurohemal contact area is significantly enlarged. The perivascular space contains degenerating nerve fibres which are undergoing phagocytosis by connective tissue cells. It is assumed that these alterations are due to the increased growth of nerve fibres towards the vessels of the “Mantelplexus”, and that, following adrenalectomy, this excessive growth leads to a pinching off of nerve fibres.
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  • 21
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    Cell & tissue research 138 (1973), S. 261-272 
    ISSN: 1432-0878
    Keywords: Extrarenal blood vessels ; Rat ; Adrenergic nerves ; Fluorescence microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The adrenergic innervation of the extrarenal blood vessels of the rat left kidney was investigated by fluorescence histochemistry and by electron microscopy. The trunk of the renal artery proximal to the aorta is elastic and appears to be very sparsely innervated. In contrast, near the kidney the renal artery—which divides into 3 to 4 large branches of the muscular type possesses a dense adrenergic innervation. The adrenergic terminal axons are situated in the adventitia close to the external elastic lamella, but only rarely in close contact with smooth muscle cells. In most instances several terminal axons are grouped and enclosed by a Schwann cell, single axons being rare. All terminal axons are able to take up and to store 5-hydroxydopamine which strongly suggests that they are adrenergic. The innervation of the renal vein is more sparse than that of the muscular arteries but somewhat denser than that of the elastic artery. In addition, close to the origin of the renal artery the presence of “small intensively fluorescent” (SIF) cells as well as of some adrenergic ganglion cells is noted. The latter are situated in the adrenergic nonterminal axon bundles, which run parallel to the blood vessels. It is concluded that the uneven adrenergic innervation along the artery as well as individual variations in the branching of the artery are the main causes of the unusually high individual variations of the NA content of this organ such as used in pharmacological experiments.
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  • 22
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Rat ; Gonadotrophic cells ; Cycle, influence of testosterone ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary 4-day cyclic adult female Wistar rats were injected subcutaneously with testosterone propionate on diestrus 1 at 16:00 and on diestrus 2 at 10:00 respectively. Non-injected females served as controls. Autopsy was performed on diestrus 2 at 23:00, and on proestrus at 14:00 and 17:00 respectively. The blue Alcian-PAS staining was used to evidence FSH (β) and LH (γ) pituitary cells. In control animals and in diestrus 2 injected females only a small number of FSH cells could be detected on diestrus 2 at 23:00. This number increased markedly on proestrus at 14:00 and decreased on proestrus at 17:00. A similar evolution was observed in diestrus 1 testosterone injected females, but the number of FSH cells appeared higher at any stage of autopsy in these females than in diestrus 2 injected females and in control rats. In control females, numerous LH cells were observed on diestrus 2 at 23:00. The number of these cells was diminished on proestrus at 14:00 and still more at 17:00. On the contrary few LH cells were detected in testosterone injected females on the evening of diestrus 2. An increase of these cells occurred on proestrus at 14:00, followed at 17:00 by only a weak diminution as established by comparison with control animals. An inhibition of FSH release and a suppression of the proestrus surge of LH were therefore supposed to cause, on one hand, the slowing up of follicular growth observed in diestrus 1 injected females and, on the other hand, the blockage of ovulation noted in both diestrus 1 and diestrus 2 treated animals.
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  • 23
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    Cell & tissue research 143 (1973), S. 107-116 
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Rat ; Pituicytes ; Organotypic culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neural lobes of adult rats have been explanted and organ-cultured for 5–10 days. While perivascular cells and neurosecretory fibers undergo a progressive degeneration, scattered pituicyte-like cells are observed mostly associated with each other in number of two or three cells for group. Cultured pituicytes are quite similar to in vivo pituicytes except for some particular features as the shape of the nucleus and the number of dense bodies. Furthermore they share with the in vivo pituicytes the phagocytic capacity which appears even increased as far as neurosecretory fibers are concerned. Finally, degenerating pituicytes and free lipid droplets are observed in the intercellular spaces: the significance of these facts is discussed and tentatively interpreted. The organotypic culture of the neural lobe seems to represent an experimental model useful to obtain a relatively pure population of pituicytes.
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  • 24
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    Cell & tissue research 143 (1973), S. 505-515 
    ISSN: 1432-0878
    Keywords: Endoplasmic reticulum ; Paracervical ganglion (Rat) ; Neurosecretion ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two new types of structure of the cytoplasm of an autonomic neuron were described: (1) Inclusions of the rough ergastoplasmic reticulum, which were named “ergastosomes”, contain finely granular material with moderately electron opaque staining with both glutaraldehyde-OsO4 and KMnO4 fixations. A short comment was made on the nature of the contents of the ergastosomes. (2) Tubular formations of endoplasmic reticulum were found in the axons and/or dendrites of the paracervical ganglion.
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  • 25
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    Cell & tissue research 146 (1973), S. 453-461 
    ISSN: 1432-0878
    Keywords: Hypophysis ; Primordium ; Rat ; Organ culture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To see whether adenohypophysial tissue has the capacity of self-differentiation, Rathke's pouch together with part of the neurohypophysial primordium was isolated from 12-(Group A), 14- (Group B) and 15-day-old (Group C) rat fetuses and cultivated for 9, 6 and 5 days, respectively. Electron microscopic examination of these explants showed many adenohypophysial cells containing electron dense granules, indicative of cytodifferentiation in all groups. Three cell types were distinguishable on the basis of the size of their granules. Variable amounts of neurohypophysial tissue were seen in some explants of Groups B and C, but not A. This “pars nervosa” contained pituicytes with lipid-like inclusions in their cytoplasm but no neurosecretory axons. The adenohypophysial cells abutting on the pars nervosa were arranged rather regularly like cells of the pars intermedia which contained a few granules of about 200 mμ diameter. From these data it is concluded that in rats granule formation in the adenohypophysial primordial cells starts in the absence of hypothalamic neurosecretory substances. It is uncertain from this study whether these cells actually contain hypophysial hormones.
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  • 26
    ISSN: 1432-0878
    Keywords: LRF ; Hypothalamic localization ; Rat ; Ependyma ; Glia ; Light and electron microscopic Autoradiography
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary Light and electron microscopic autoradiographic analysis of the medial basal hypothalamus of rat brains incubated for 30 and 60 minutes in tritiated luteinizing releasing factor (3H-LRF) revealed selective uptake in the form of silver grains over specialized ependyma (tanycytes) and perivascular glial cells in the palisade-contact zone of the median eminence. The functional capacity of tanycytes and glia are discussed in light of these data.
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  • 27
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    Cell & tissue research 144 (1973), S. 453-466 
    ISSN: 1432-0878
    Keywords: Lacrimal gland ; Rat ; Duct system ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The duct system of the rat exorbital lacrimal gland consists of intercalated ducts, interlobular ducts and excretory ducts. The morphological changes from one type of duct to the next are gradual. At the light microscopical level this consists of a change from a bilaminar epithelium in the intercalated ducts to an epithelium, consisting of approximately three layers — which may be pseudostratified — in the excretory ducts. The basal layer of the intercalated ducts consists of myoepithelial cells, whereas the inner epithelial cells may have both a secretory and an electrolyte transporting function. The interlobular duct epithelium contains many cells with deep infoldings of the basolateral plasma membranes and associated mitochondria, suggesting a similar function to the striated duct epithelium in salivary glands. Numerous basal cells in this epithelium have tentatively been interpreted as unusual myoepithelial cells. Nerve terminals have been observed in the ductal epithelium.
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  • 28
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    Cell & tissue research 150 (1974), S. 493-496 
    ISSN: 1432-0878
    Keywords: Serotonin ; Neurotransmitter ; Myenteric plexus ; Rat ; Histofluorescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Several recent studies suggested that serotonergic neuron-like elements are present in the guinea pig ileum. The present paper reports an extensive study of the digestive tract of the rat with the use of a histofluorescence technique. Administration of the serotonin precursor, tryptophan, associated with a monoamine oxidase inhibitor, did not allow histochemical demonstration of rapidly fading, yellow fluorescent, 6-hydroxydopamine-resistant neurons; conversely such neurons were readily detected in the brain. It is concluded that serotonergic neuron-like elements cannot be detected histochemically in the rat myenteric plexus area after chemical sympathectomy.
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  • 29
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    Cell & tissue research 151 (1974), S. 457-469 
    ISSN: 1432-0878
    Keywords: Juxtaglomerular apparatus ; Rat ; Adrenalectomy ; Renin and secretory granules ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Reaktion des juxtaglomerulären Apparates auf Adrenalektomie wurde untersucht. Im Stadium der Nebenniereninsuffizienz, sechs Tage nach der Operation, wurde quantitativ morphometrisch eine Abnahme der Volumendichte der Sekretgranula (von 32% auf 16%) festgestellt. Golgi-Apparat und Ergastoplasma proliferieren stark, wobei insbesondere die erweiterten Cisternen des Ergastoplasmas auffallen.
    Notes: Summary The response of the Juxtaglomerular apparatus to bilateral adrenalectomy was studied in rats. After the sixth postoperative day, symptoms of severe adrenal insufficiency had developed. In the Juxtaglomerular cells, the volume density of the secretory granules decreased from 32% to 16%. The Golgi apparatus and rough endoplasmic reticulum underwent considerable proliferation, the latter showing strikingly enlarged cisternae.
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    Cell & tissue research 151 (1974), S. 525-536 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Rat ; Sex differences ; Gonadal hormones ; Karyometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Adrenal glands of adult female rats are heavier than the glands of corresponding male rats. Postpubertal orchiectomy increases the adrenal weight, an effect restored by testosterone replacement. Under the same conditions ovariectomy of 8 weeks duration does not change the adrenal weight while estradiol replacement enhances the relative adrenal weight. Karyometric studies have shown that nuclei in the female zona fasciculata cells are larger (app. 18%) than those of the male. Similar but only slight differences (2%) were observed in the zona reticularis. Orchiectomy results in enlargement of cell nuclei within all zones of the adrenal cortex; testosterone replacement has the opposite effect. Ovariectomy of 8 weeks duration slightly enhances the volume of nuclei of the zona glomerulosa cells, has no effect on the nuclei of the zona fasciculata and reduces the volume of nuclei in the zona reticularis. Estradiol replacement reduces the volume of nuclei of the zona glomerulosa cells but increases nuclear volume in the zona fasciculata and in the zona reticularis. Thus testosterone has an inhibitory effect on the adrenal cortex of the rat while the physiologic effect of estradiol on the morphology of this gland, particularly on the zona fasciculata cells is rather dubious. The author wishes to thank Mrs. B. Westerska and Miss K. Siejak for excellent technical assistance.
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    Cell & tissue research 151 (1974), S. 537-547 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Rat ; Sex differences ; Gonadal hormone ; Stereologic studies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Adult female rats have heavier adrenals than males. Orchiectomy increases the adrenal weight, an effect reversed by testosterone. Neither ovariectomy nor estradiol replacement has an effect on absolute adrenal weight. The stereologic analysis of the volume fractions of particular adrenocortical zones have shown that the volume fraction of the zona glomerulosa in females is smaller as compared with males. On the contrary, the volume fractions of the fasciculata and reticularis zones are higher in female than in male rats. In both sexes gonadectomy and gonadal hormone replacement has an effect on the volume fractions of particular adrenocortical zones, these changes being more pronounced due to orchiectomy or testosterone replacement. The adrenal cortex of all experimental groups contains a similar quantity of parenchymal cells. The cytoplasm volume of a single adrenocortical cell is higher in all zones of the female adrenals as compared with the male. Orchiectomy increases the volume of the cytoplasm in fasciculata and reticularis cells. This effect was reversed by testosterone. Neither ovariectomy nor estradiol replacement has an effect on the volume of the cytoplasm in the fasciculata and reticularis cells. These studies have shown that sex differences with regards to rat adrenal size and weight depend upon the “physiologic atrophy” of the male adrenal cortex, while neither ovariectomy (8 weeks after operation) nor estradiol replacement has a conspicuous effect on the morphologic changes of this gland.
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    Cell & tissue research 136 (1973), S. 111-120 
    ISSN: 1432-0878
    Keywords: Median eminence ; Rat ; Granular vesicles ; Ultrastructure ; Quantitative evaluation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to characterize different sub-zones in the palisade zone of the rat median eminence, quantitative ultrastructural parameters were applied to brains fixed in aldehyde-osmium tetroxide. The palisade zone has been subdivided in 4 successive sub-zones. Increasing numbers of granular vesicles (GV), especially those smaller than 110 nm, are observed from dorsal to ventral sub-zones. There also are more GV per unit area of nervous tissue in the perivascular than in the more dorsal sub-zones. The individual nerve profiles exhibit a larger size in the perivascular layer than in the more dorsal areas, whereas the number and size of nerve profiles devoid of vesicles diminish from dorsal to ventral. As a consequence more GV occur in the perivascular nerve profiles. In the GV containing nerve profiles the concentration of GV is, however, constant in the different sub-zones. A fluctuating size of the preterminal and terminal parts of the nerve fibres is suggested.
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    Cell & tissue research 136 (1973), S. 177-182 
    ISSN: 1432-0878
    Keywords: Rat ; Epididymis ; Effect of vasectomy ; Spermatozoa ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Epididymal biopsies from rats that had undergone unilateral or bilateral vasectomies from one to eight months previously were compared with biopsies from their contralateral side or from normal controls to ascertain what ultrastructural changes had occurred. After vasectomy, spermatozoa appeared to dissolve in the lumen of the caput epididymidis and to be absorbed by the principal cells. About 5 weeks after vasectomy, numerous lamellar accumulations became apparent in the supernuclear region. Their resemblance to lysosomes or residual bodies was confirmed by an acid phosphatase reaction. After 10 weeks, similar lamellar and polymorphic accumulations on the contralateral side of animals with unilateral vasectomies indicated that resorption had also increased on the unligated side.
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    Cell & tissue research 138 (1973), S. 223-237 
    ISSN: 1432-0878
    Keywords: Aorta, endothelium ; Rat ; Transport of serum lipoproteins ; Radioautography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The transport of 125I-labeled serum lipoproteins through the aortic endothelium was studied by radioautography. Rat aorta and heart was perfused in vitro with a medium containing human very low density (VLDL), low density (LDL), high density lipoprotein (HDL), delipidated HDL apolipoprotein or rat HDL. In all lipoproteins more than 95% of the radioactivity was TCA precipitable and lipid radioactivity was from 2–4% in HDL, 4–6% in LDL, 7–15% in VLDL. After 18–60 min of perfusion and wash with unlabeled medium, most of the aortic radioactivity was TCA precipitable and the percent of lipid counts was similar to that in the original lipoprotein. Following perfusion with VLDL, LDL, or HDL the radioautographic reaction was seen over the endothelium, the subendothelial space and the inner media, and was separated by an unlabeled zone from the reaction present over the adventitia. Uniform labeling of the entire wall was found after perfusion with HDL apolipoprotein. The presence of silver grains over endothelial cells in regions rich in plasmalemmal vesicles suggested that these organelles participate in the transport of the labeled lipoprotein, as was shown for lactoperoxidase (Stein and Stein, 1972). The present data indicate that cholesterol may enter the aortic wall as a constituent of lipoprotein particles. Since an HDL particle carries less than 1/20 of the cholesterol present in a LDL particle, it seems that the lower susceptibility of the female to atheromatosis might be related to the higher ratio of HDL to LDL particles in the female serum.
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    Cell & tissue research 137 (1973), S. 141-143 
    ISSN: 1432-0878
    Keywords: Juxtaglomerular cells ; Rat ; Granulation index ; Diurnal rhythm ; Statistical evaluation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Das Granulations-Index der juxtaglomerulären epitheloiden Zellen der Rattenniere unterliegt tagesrhythmischen Schwankungen, wobei die berechneten Werte in den Nachtstunden significant höher sind als in den Tagesstunden.
    Notes: Summary Marked diurnal changes occur in the granulation index of the juxtaglomerular cells in the rat kidney. According to the results the night values are significantly higher than those obtained in daytime.
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    Cell & tissue research 140 (1973), S. 309-314 
    ISSN: 1432-0878
    Keywords: Pituitary Gland ; Rat ; Somatotropin ; Cellular Response ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The response of somatotrophs to large doses of purified bovine growth hormone was examined in uninephrectomized rats drinking 1% sodium chloride in an attempt to prolong the action of the hormone. Growth hormone produced a triphasic response in the ultrastructure of somatotrophs. Uninephrectomy and salt alone induced no changes in somatotrophs as compared to unoperated animals consuming tap water. In the first phase (3 days) the cross sectional area of the cell increased, the size of the largest granule per cell as well as the number of granules per cell increased significantly. All these parameters then reached control level after 7 days of injections during a second phase. Suppression of somatotrophs by exogenous growth hormone was evident by 16 days (third phase) when the area of the cell, the size of the largest secretory granule as well as the number of granules per cell all decreased significantly. Somatotrophs apparently did not react to suppression by a lysosomal mechanism inasmuch as no increase in the number of lysosome-derived structures was seen even at 16 days.
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  • 37
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    Cell & tissue research 143 (1973), S. 143-147 
    ISSN: 1432-0878
    Keywords: Rat ; Suprachiasmatic nucleus ; Blinding ; Retinohypothalamic connections ; Karyometry
    Source: Springer Online Journal Archives 1860-2000
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    Description / Table of Contents: Zusammenfassung Radioaktiv markierte Aminosäuren werden bei Säugetieren nach intraokulärer Injektion nicht nur zu den primären optischen Kerngebieten, sondern auch in den Nucleus suprachiasmaticus des Hypothalamus transportiert (Moore und Lenn, 1972; Hendrickson, Wagoner und Cowan, 1972; Moore, 1973). Dieser Befund macht eine direkte Verknüpfung zwischen der Netzhaut und dem sekretorisch aktiven Nucleus suprachiasmaticus wahrscheinlich, obwohl mit Silbertechniken eine solche Verbindung nicht sicher nachgewiesen werden konnte. Karyometrische Studien am Nucleus suprachiasmaticus männlicher Wistar-Ratten zeigen 6 Tage nach beidseitiger Blendung eine signifikante Abnahme der Zellkerndurchmesser. Dieses Ergebnis spricht für eine Aktivitätsänderung der Neurone im Nucleus suprachiasmaticus geblendeter Ratten.
    Notes: Summary Intraocular injection of labeled amino acids results, in different mammals, in an accumulation of radioactive material not only in the primary optic centers but also within the hypothalamic suprachiasmatic nucleus (Moore et al., 1972; Hendrickson et al., 1972; Moore, 1973). This finding argues in favour of a direct connection between the retina and the secretory suprachiasmatic nucleus although silver techniques do not show such a pathway. In male Wistar rats the nuclear diameter of the suprachiasmatic neurons decreases significantly 6 days after bilateral experimental ablation of the retina. These results indicate an alteration in activity of the suprachiasmatic neurons in blinded rats.
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    Cell & tissue research 143 (1973), S. 535-547 
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Rat ; Mitoses, topographic distribution ; Influence of fixation ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
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    Description / Table of Contents: Résumé Les mitoses de l'adénohypophyse du rat mâle ont été examinées comparativement après fixation par perfusion et après fixation par immersion. Après fixation par perfusion la répartition topographique des mitoses dans le parenchyme est homogène, et l'index mitotique est de 1,85 pour 1 000 cellules. Après fixation par immersion, la densité des mitoses décroit de la périphérie vers le centre, et l'index mitotique n'est que de 0,80 mitoses pour 1 000 cellules. La lenteur de pénétration du fixateur pendant l'immersion est tenue pour principal responsable des différences observées. Elle entraîne une modification de l'aspect des mitoses, telle que plus de la moitié d'entre elles ne sont pas identifiables et échappent aux comptages.
    Notes: Summary The mitoses of the adenohypophysis in male rats have been observed comparatively after fixation by perfusion and fixation by immersion. After fixation by perfusion, the topographic distribution of mitoses throughout the parenchyma is homogenous and the mitotic index is 1.85 for 1 000 cells. After fixation by immersion, the density of the mitoses is decreasing from the periphery towards the center and the mitotic index is only 0.80 for 1 000 cells. The slow penetration of the fixative during fixation by immersion is considered to be the main cause in the differences observed. This slow action causes a modification in the aspect of the mitoses, and more than fifty percent of them cannot be identified and escape to the counts.
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    Cell & tissue research 147 (1974), S. 259-269 
    ISSN: 1432-0878
    Keywords: Nerve endings ; Hair ; Rat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Palisade-shaped nerve endings of the small normal hairs of the rat snout were examined with the electron microscope (fixation by perfusion). The terminals are located inside the ‘glassy membrane’ in the area of the neck of the hair root. The 10–20 radially arranged terminal axons are in direct contact with the basement membrane of the epithelium of the external root sheath. The axons are surrounded on all sides by leaf-shaped processes of the Schwann cells. The surfaces of these cell processes are marked by numerous vesicle-like invaginations (approx. 1000 Å dia.). Transverse sections from several areas of the palisadeshaped nerve endings are compared with longitudinal sections. In the upper area ‘empty’ vesicles (approx. 500–600 Å in diameter) occur, along with electron-dense vesicles (approx. 800–1100 Å in diameter); in the middle area, the axons are distended and contain accumulations of mitochondria.
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  • 40
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    Cell & tissue research 147 (1974), S. 183-190 
    ISSN: 1432-0878
    Keywords: Kidney ; Rat ; Bowman's capsule ; Experimental hypertension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The parietal layer of Bowman's capsule was examined in the rat in control animals and in animals made hypertensive by treatment with desoxycorticosterone acetatesaline and by clipping of the renal artery. At an early stage of elevation of blood pressure and, occasionally, prior to elevation of blood pressure, the epithelial cells of this layer showed basal cytoplasmic protrusion and reduplication accompanied by an increase in the thickness of the basement membrane. These changes preceded evidence of glomerular or renal arteriolar pathology. They presumably reflect either a response of this layer to increased blood pressure and modified glomerular function, or a direct effect of the factors that also induces blood pressure elevation. In either case, they imply a greater functional significance for the parietal layer than has usually been attributed to it.
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  • 41
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    Cell & tissue research 148 (1974), S. 57-67 
    ISSN: 1432-0878
    Keywords: Prostate ; Rat ; Cyproterone ; Alterations ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The dorsal lobe and the coagulating gland of the rat prostate were studied after administration of the anti-androgenic compound Cyp A for varying periods (7–20 days). There was a general involution of the organs with macroscopic atrophy and reduced amount of secretory material. Ultrastructurally the cells were pale, contained less organelles as compared with the controls, loss of cytoplasm and reduction both of cell height and width. The major changes also included reduction of the Golgi area, the rough endoplasmic reticulum and the number of free ribosomes. Within the dorsal lobe prominent nuclear changes were found, comprising different types of intranuclear inclusions of membranous configurations. The alterations observed in the present study are similar to the changes which were found in castrated animals and are consistent with atrophy. The results are discussed in relation to the available biochemical and autoradiographic data on the different lobes.
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  • 42
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    Cell & tissue research 125 (1972), S. 277-288 
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Rat ; Exocytosis ; Freeze-etching ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neural lobes of rats subjected to severe acute haemorrhage under sodium pentobarbitone anaesthesia were examined electron microscopically and the ultrastructure compared with that in anaesthetised and unanaesthetised controls. Changes in the localisation and numerical distribution of elementary granules and small vesicles in the neurohypophysial nerve endings of bled rats were consistent with the occurrence of exocytosis. The occurrence of “exocytotic profiles” was observed more frequently in freeze-etched tissue samples as compared with the material fixed for conventional electron microscopy. The ratio of small vesicles: elementary granules was shown to be significantly increased (P〈0.005) in the nerve endings of neural lobes from bled rats. Equally, the numbers of exocytotic profiles related to 1000 μm2 of neurohypophysial tissue area were significantly greater (P〈0.005) in bled rats.
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  • 43
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    Cell & tissue research 125 (1972), S. 289-294 
    ISSN: 1432-0878
    Keywords: Accessory optic system ; Rat ; Blood vessels ; Extracellular space ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary Two types of capillaries were found in the medial terminal nucleus of the rat accessory optic system. Type one capillaries are surrounded by glial processes and lack a perivascular space, whereas the type two capillaries and arterioles show a distinct extracellular perivascular space often filled with collagen fibrils. An internal as well as an external basal lamina lines these spaces. No fenestration of the endothelium was observed.
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  • 44
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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
    Source: Springer Online Journal Archives 1860-2000
    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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  • 45
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    Cell & tissue research 125 (1972), S. 404-414 
    ISSN: 1432-0878
    Keywords: Renal medulla ; Rat ; Interstitial ground substance ; Fixation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Das Interstitium des inneren Nierenmarkes von Ratten wurde nach Anwendung verschiedener Fixierungsarten und Versuchsanordnungen elektronenmikroskopisch untersucht. Neben Bindegewebszellen und kollagenen Fibrillen enthält der interstitielle Raum bandförmige, basalmembranartige Strukturen, in deren weiträumigen Maschen zwei weitere Komponenten, nämlich ein feingranuläres und feinfilamentäres Material sowie kontrastreiche, globuläre Partikel liegen. Diese beiden Formelemente stellen sich bei den verschiedenen Fixierungsarten und Versuchsanordnungen unterschiedlich dar. Bei der feingranulären und feinfilamentären Komponente handelt es sich wahrscheinlich um interstitielles Blutplasma. Diese Deutung wird gestützt durch die morphologische Ähnlichkeit mit dem Blutplasma der Blutgefäße, die unterschiedliche Darstellbarkeit nach Glutardialdehyd-und Formalinfixierung sowie durch die Befunde nach Gefäßperfusion und Nierenvenenstauung. Das Verhalten der globulären Partikel nach OsO4-Einwirkung steht in Einklang mit der schon früher gegebenen Interpretation als präzipitierte saure Mukopolysaccharide. Ihr elektronenoptisches Bild wird im Vergleich zur bekannten makromolekularen Struktur der Mukopolysaccharid-Protein-Moleküle diskutiert.
    Notes: Summary The interstitial ground substance in the inner medulla of the rat kidney is examined electron microscopically after fixation with various fixation agents and under different experimental conditions. The papillary interstitium contains besides interstitial cells and few collagen fibrils basement membrane like material and two other components, fine granular-fibrillar elements and globular particles with heavy contrast. The appearance of the two latter interstitial components varies according to the different fixation agents used and to the experimental conditions. The fine granular and fine fibrillar material surrounds the globular particles numerously after glutardialdehyde-fixation but scarcely after formaldehyde-fixation. It increases after renal vein occlusion, but is diminished or absent, if the kidney is rinsed bloodfree. These results allow to conclude that this material represents interstitial bloodplasma. The behaviour of the globular particles after OsO4-fixation agrees well with the earlier interpretation according to which they represent precipitated acid mucopolysaccharides. Their electron microscopic appearance is discussed in comparison with the known macromolecular structure of the acid mucopolysaccharides.
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    Cell & tissue research 125 (1972), S. 432-447 
    ISSN: 1432-0878
    Keywords: Synaptosomes ; Synapses ; Rat ; Cerebral cortex ; Glutaraldehyde/E-PTA
    Source: Springer Online Journal Archives 1860-2000
    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 125 (1972), S. 480-496 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Rat ; Normal ; Hypophysectomy ; Structural alteration
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    Topics: Biology , Medicine
    Notes: Summary The adrenal cortex of normal and hypophysectomized rats was observed by electron microscopy 5–90 days after the operation and, chiefly, the degeneration mechanism of the cortical tissue was discussed. In normal rats mitochondrial inner structures are generally tubular in shape in glomerulosa cells, vesicular (and tubulo-vesicular) in fasciculate cells and tubulo-vesicular (and vesicular) in reticularis cells. Some mitochondria in a few glomerulosa cells show long straight tubular crests in normal as well as hypophysectomized rats. Usually lipid droplets in normal glomerulosa, fasciculate and reticularis cells are surrounded by elements of smooth endoplasmic reticulum, which are very closely associated with mitochondria. About 10–25 days after hypophysectomy, most mitochondria in fasciculate and reticularis cells show tubular crests, and numerous electron lucent lipid droplets are accumulated in these cells. These droplets occupy most parts of the cytoplasm and are sometimes in contact with one another or with mitochondria. The elements of smooth endoplasmic reticulum and Golgi apparatus are markedly reduced in number and size. About 10–90 days after the hypophysectomy, the degenerative cortical cells containing irregularly shaped nuclei, heterogeneously dense bodies in various sizes, and a large number of electron lucent lipid droplets are seen. The author speculates that most fasciculate and reticularis cells degenerate because of a disorder in the lipid metabolism, since ACTH release, which is necessary for synthesis of corticosteroid hormones from cholesterol, is absent in hypophysectomy. The fatty degeneration of the fasciculate and reticularis cells is considered to be a main cause for attenuation of the cortical tissue. Sometimes atrophied cortical cells without lipid droplets are also found 60–90 days after hypophysectomy.
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    Cell & tissue research 144 (1973), S. 167-178 
    ISSN: 1432-0878
    Keywords: Prostate ; Rat ; Castration ; Alterations ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ventral, lateral and dorsal lobes of the rat prostate were studied 2, 3, 5, 7 and 21 days after castration. The major changes were a general reduction of the Golgi area and the RER. The cells became pale and contained less organelles compared with the normals. One of the most conspicuous changes were enormous autophagic vacuoles which were present already after 2 days, seemed to reach a numerical peak 3 days after castration and were seldom encountered after 7 days. Increased number of dense bodies were found within the same period. Lipid droplets were observed in the basal cytoplasm of the epithelial cells, especially in the ventral lobe. The basal cells showed the same involution as in the ordinary epithelium. In addition, macrophages were relatively numerous, and between the epithelial cells also lymphocytes were found. The results are discussed in relation to biochemical data on the different lobes.
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    Cell & tissue research 144 (1973), S. 179-189 
    ISSN: 1432-0878
    Keywords: Seminal vesicles ; Coagulating Gland ; Rat ; Castration ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The seminal vesicles and the coagulating gland of the rat were studied 2, 3, 5, 7 and 21 days after castration. The major changes within the seminal vesicles were primarily formation of whorls of the rough endoplasmic reticulum (RER), followed by a general atrophy with a numerical reduction of the RER-profiles, and with general simplification of the cytoplasm due to loss of the organelles. It was a gradually reduction of secretion granules, diminution of the Golgi apparatus, formation of pigment bodies and autophagic vacuoles. Lipid droplets were observed in the basal cytoplasm of the epithelial cells. In the coagulating gland, similar changes occurred within the Golgi area and the lysosome complex. On the other hand, cisternae of the basal endoplasmic reticulum tended to persist in many cells. The similarity in response strongly suggests that the pathogenetic mechanisms are similar in both organs, i.e. atrophy due to deprivation of the androgenic stimulus. The deprivation of androgen gave rise to an inflammatory-like process with infiltration of lymphocytes and macrophages. The increased number of macrophages may indicate that they contribute in some way to the involution of the prostate by removing the material in the autophagic vacuoles.
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    Cell & tissue research 150 (1974), S. 95-105 
    ISSN: 1432-0878
    Keywords: Mucosal mast cells ; Rat ; Compound 48/80 ; Degranulation, Release ; Light microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Mast cells in the tongue and lamina propria of the duodenal mucosa, representing two cell types with different morphological, histochemical and functional properties have been studied under the electron microscope. Both cell types were found to contain similar moderately electron dense and homogeneous granules surrounded by a tight membrane constituting the basic ultrastructural characteristics of mast cells. The mucosal mast cells, however, contained fewer granules per cell and the individual granules often exhibited considerable variation in size. In addition the mucosal mast cells, unlike those of the tongue, peritoneum and skin, had a smooth plasma membrane lacking microvilli and possessed irregularly shaped or lobulated nuclei. In the tongue mast cells, administration of Compound 48/80 caused the formation of vacuoles around the granules, expulsion of granules from the cells and disintegration of the granular matrix, but no changes that could be attributed to 48/80 could be found in the mucosal mast cells.
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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. 231-243 
    ISSN: 1432-0878
    Keywords: Pinealocyte-resembling cells ; Habenular region ; Sympathetic nerve fibres ; Ontogenetic development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cells of the pineal gland, the pineal stalk, and the lamina intercalaris contain 5-HT and are innervated by sympathetic nerve fibres. These peripheral nerve fibres continue rostrally from the lamina intercalaris and run into the central nervous tissue of stria medullaris and the habenular nuclei. Pharmacological treatment to increase the cellular 5-HT content revealed that the sympathetic fibres are in close relation to yellow fluorescent cells embedded in the brain tissue. These yellow fluorescent cells develop very late in the ontogenetic development (three weeks or more postnatally) and are preceded by ingrowth of sympathetic fibres into the brain tissue. The results support the hypothesis that the cells found in the habenular region are of pinealocyte rather than neuronal nature, but it is possible that they differ in certain aspects from the cells of the pineal gland proper.
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  • 53
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Rat ; Vasopressin release ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
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    Description / Table of Contents: Résumé Le lobe postérieur de l'hypophyse a été examiné sur coupes ultrafines chez 45 rats (24 normaux, 17 déshydratés respectivement 1, 2 et 4 jours, et 4 anesthésiés à l'éther), après fixation au glutaraldéhyde ou selon la méthode de Karnovsky, post-fixation osmiée et double contraste à l'acétate d'uranyle et au citrate de plomb. Des fibres neurosécrétoires sombres et claires sont reconnaissables, mais les données manquent encore pour interpréter cette différence. Des densifications juxta-membranaires sont observées dans les terminaisons neurosécrétoires là où se trouvent des amas de microvésicules. Des fibres neurosécrétoires traversent parfois des pituicytes; il est aussi souvent observé des fibres, chargées de granules, libres dans un espace péricapillaire. Les espaces péricapillaires, ramifiés en tous sens loin des vaisseaux, développent une large surface de contact avec les extrémités nerveuses et les prolongements de pituicytes. Dans des conditions techniques bien contrôlées, la déshydratation n'entraîne pas de modifications appréciables des granules de neurosécrétat après 24 h. Ensuite les granules sont diminués en nombre, de façon très considérable le 4e jour; mais les granules restants ont un contenu dense normal; jamais il n'a été observé d'aspects de ≪granules vides ≫. Après anesthésie prolongée à l'éther, il n'y a aucune modification visible ni du nombre, ni de la densité des granules. Ces observations sont discutées quant au mécanisme de l'excrétion de vasopressine; elles sont en faveur de l'existence de deux pools hormonaux, l'un libre et rapidement disponible, l'autre plus fortement lié et certainement contenu dans les granules jouant le rôle de réserve. Toutefois un mécanisme d'exocytose granulaire ne peut être formellement exclu.
    Notes: Summary Hypophysial neural lobes of 45 rats (24 controls, 17 dehydrated resp. 1, 2 and 4 days, and 4 ether anesthetized) were fixed either with glutaraldehyde or according to Karnovsky and post-fixed in osmium tetroxyde; ultrathin sections were stained by uranyl acetate and lead citrate. Dark and clear neurosecretory fibres were observed, but sufficient data are still lacking for a valuable interpretation of these aspects. Juxta-membraneous densifications are visible in limited areas of neurosecretory terminals where clusters of microvesicles are present. Neurosecretory fibres happen to be completely encircled by pituioyte cytoplasm; fibres loaded with elementary granules are frequently encountered running free in a pericapillary space. Pericapillary spaces stretch out branching far away from vessels, resulting in a widespread contact with nerve terminals and pituicyte processes. In accurately controlled technical conditions, dehydratation does not result in any noticeable change of neurosecretory granules after 24 h. A decrease of the number of granules follows and is extremely conspicuous after 4 days; though, remaining granules keep a normal dense content, and aspects of “empty granules” have never been observed. After prolonged ether anesthesia, no visible change either in number or electron density of granules was observed. These findings are discussed in consideration of the mechanism of vasopressin release; they support the hypothesis of two hormonal pools, one of which would be free and rapidly available for release, the other being more tightly bound and certainly located in granules representing a storage site. Though granular exocytosis cannot be absolutely excluded.
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    Cell & tissue research 109 (1970), S. 384-397 
    ISSN: 1432-0878
    Keywords: Heart muscle cells ; Electron microscopy ; Quantitative ; Asphyxia ; Rat
    Source: Springer Online Journal Archives 1860-2000
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    Description / Table of Contents: Zusammenfassung Normale und hypoxische Herzmuskelzellen aus der Wand des linken Ventrikels der Ratte wurden quantitativ-morphologisch anhand von elektronenmikroskopischen Längsschnitten nach Perfusionsfixierung untersucht. In normalen Zellen waren alle Myofibrillen relaxiert, die mittlere Sarcomerlänge betrug 2,2 μm. Die Schnittfläche wurde zu 55% von Myofibrillen, zu 27% von Mitochondrien und zu 18% von Grundplasma und Reticulum eingenommen. Die zwischen den Myofibrillen liegenden Mitochondrien waren längsoval und im Mittel 2,3mal so lang wie breit. Es bestand kein Unterschied zwischen subendokardial und subepikardial gelegenen Zellen. 10 min nach Erstickung der Tiere waren in den sonst unauffälligen Muskelzellen die Glycogengranula vermindert. Nach 20 min führte die Hypoxie zu einer Zunahme der relativen Schnittfläche der Mitochondrien um etwa 16% und zu einer beginnenden Kontraktur der Myofibrillen (Sarcomerlänge 2,0 μm). 20 min Hypoxie in Hypothermie (25–30°C intrathorakal) veränderte die normale Zellstruktur dagegen kaum. Wenn die Herzen während der 20 min dauernden Hypoxie in Normothermie mit einer procainhaltigen sauerstoff- und glucosefreien Blutersatzlösung durchspült wurden, waren die Myofibrillen relaxiert, die Schwellung der Mitochondrien dagegen wurde nicht reduziert. 30 min nach Erstickung wurde die Kontraktur stärker (Sarcomerlänge 1,7 μm). Nach 60 min bildeten sich Superkontraktionsknoten, einzelne Myofibrillen waren in Höhe der I-Bänder unterbrochen. Die Cristae der Mitochondrien wichen auseinander, die Schnittfläche der Mitochondrien hatte um 27% zugenommen. Während in Normotherapie eine Asphyxie des Tieres bereits nach 10 min die Herzmuskelzellen funktionell schwer schädigt, ist die Schädigung morphologisch erst nach 20 min eindeutig. Das bedeutet, daß für die elektronenmikroskopische Präparation eine Hypoxie von unter 10 min bedeutungslos ist. Hinsichtlich der morphologischen Manifestationszeit für die Unterbrechung der Sauerstoffversorgung stimmen unsere Befunde an Herzmuskelzellen gut mit vergleichbaren Angaben an Leberzellen überein.
    Notes: Summary In heart muscle cells of the left ventricle of rats the distribution of cell organelles and their reaction to hypoxia were investigated by electron microscopy. In normal hearts fixed by perfusion with aldehydes, the mean sarcomere length was 2.2 μm. 27% of the longitudinal sectional area was occupied by mitochondria, 55% by myofibrils and 18% by sarcoplasmic reticulum and ground plasm. The mitochondria situated in rows between the fibrils were oval and measured 2.3 times more in length than in width. There was no difference between cells from subendocardial and subepicardial regions. 10 min hypoxia (complete occlusion of the trachea) did not affect the appearance of muscle cells but diminished the number of glycogen granules. After 20 minutes the area occupied by mitochondria was increased by 16%, the mitochondria between the myofibrils were more spherical and only 1.5 times longer than wide. The sarcomeres shortened to 2.0 μm. With hypothermia (25–30°C) hypoxia of 20 minutes duration did not affect the cell structure. Perfusion of the heart by a saline solution, which contained procaine but neither oxygen nor glucose, for 20 minutes prevented shortening of the sarcomeres but not swelling of the mitochondria. 30 minutes after occlusion of the trachea the myofibrils shortened to a sarcomere length of 1.7 μm. After 60 minutes irregularly and excessively contracted myofibrils appeared and some sarcomeres were interrupted at the level of the I-bands. In some of the swollen mitochondria the cristae were widely separated. The increase of the area occupied by mitochondria was 27%. Asphyxia affects heart muscle cells severely with respect to function within 10 min, but morphologically it takes 20 min before a definite effect can be noticed. As to the time after which lack of oxygen is manifested morphologically, our results are consistent with findings in liver cells.
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  • 55
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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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  • 56
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    Keywords: Ependyma ; Thiobarbiturate narcosis ; Cell nucleus shrinkage ; Rat
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    Description / Table of Contents: Zusammenfassung Im Ependym des Hypothalamus wurde das Verhalten der Zellkern-Membran nach ausgedehnter intraperitonealer Thiobarbiturat-Narkose untersucht. Die Kernmembran ist gefaltet, der Zellkern zeigt Zeichen von Schrumpfung. Diese Veränderung ist reversibel und wird nicht von der mit der Narkose verbundenen Entwässerung verursacht. Elektronenmikroskopische Untersuchungen lassen einen normalen Stoffwechsel vermuten, Zeichen von Pyknose fehlen.
    Notes: Summary Effects on the nuclear membrane were investigated in hypothalamic ependymal cells of the rat during prolonged intraperitoneal thiobarbiturate narcosis. The nuclear membrane of the nucleus was folded and the nucleus showed signs of shrinkage. These alterations were reversible and did not depend on the dehydration which developed during the narcosis. Ultrastructural signs and the absence of pyknosis suggested that metabolism during nuclear shrinkage may be normal.
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  • 57
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    Cell & tissue research 113 (1971), S. 157-173 
    ISSN: 1432-0878
    Keywords: Prostate ; Development ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The postnatal development of the rat prostate has been studied with the electron microscope. Major developmental changes begin during the second week after birth and involve organelles associated with the formation of secretions. The amount of granular endoplasmic reticulum and the size of the Golgi complex increase greatly. Large vacuoles that probably contain secretory material are formed, and the lumen of the prostatic acini appears to contain secreted material. Large lysosomes with polymorphic interiors are present as early as 10 days after birth, and they become numerous by the end of the third week. Differences in fine structure between the different lobes of the prostate are detectable in 10–14 day old rats. The subsequent differentiation of the granular endoplasmic reticulum into the forms characteristic of the different prostatic lobes is described. The initial changes in the prostate occur in advance of sexual maturity of the animal, and the adult appearance of the gland is attained by 4–5 weeks after birth.
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  • 58
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    Keywords: Neurosecretory cells ; Rat ; Cytoplasmic bodies resembling nucleoli ; Paranucleolar and coiled bodies
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    Notes: Summary A distinctive cytoplasmic inclusion, termed nucleolus-resembling body, was identified in the neurons, but not in the glial cells, of the medial vascular prechiasmatic gland, the preoptic recess and the anterior part of the suprachiasmatic area in the rat. This ultrastructure which lacks a limiting membrane is made of an entanglement of tightly packed filaments, 60–70 Å in diameter. Each filament consists of smaller units, 15–20 Å thick. Usually, only one such ultrastructure is present in a cell, but at time two were identified. It is present in most neurosecretory cells. It is surrounded by polyribosomes in the perikaryon of the nerve cells. Furthermore, it is linked to peripherally located ribosomes by means of filaments, 70 Å in diameter. A possible function in protein synthesis of structural components, such as neurofilaments, is hypothesized. Two distinctive fibrillar areas were identified in the nucleolus according to the tightness with which fibrils were packed together. Their significance is discussed. Nucleolar extrusions were never observed in our studies. Paranucleolar and coiled bodies were identified in the nuclear sap. The mechanism of formation and the significance of these bodies are discussed.
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  • 59
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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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  • 60
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    Keywords: Adenohypophysis ; Pars intermedia ; Corticotrophic cells ; Rat
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    Description / Table of Contents: Résumé Nos observations démontrent l'existence de deux types de cellules glandulaires dans la pars intermedia de l'hypophyse du rat: des cellules propres, à M.S.H., dont les grains de sécrétion sont détruits par la fixation osmiée et relativement bien conservés par la fixation au glutaraldéhyde; des cellules à petits grains denses, osmio-résistants, qui s'apparentent morphologiquement aux éléments corticotropes de l'antéhypophyse. L'existence bien connue d'A.C.T.H. ou, plus précisément, d'un facteur ≪A.C.T.H.-like≫ dans le lobe neuro-intermédiaire nous fait considérer comme très vraisemblable la nature corticotrope de ce deuxième type cellulaire de la pars intermedia.
    Notes: Summary Two types of glandular cells have been shown to occur in the intermediate lobe of the rat hypophysis: 1) M.S.H. producing cells whose secretory granules are destroyed by osmium fixation and relatively well preserved by glutaraldehyde fixation, 2) cells with small dense osmium resistant granules being morphologically similar to the corticotrophic cells of the anterior lobe. The well known occurrence of A.C.T.H. or, more precisely, of an “A.C.T.H.-like” factor in the neuro-intermediate lobe makes the corticotrophic nature of this second cell type very likely.
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    Cell & tissue research 117 (1971), S. 191-211 
    ISSN: 1432-0878
    Keywords: Sensory neurons ; Rat ; Nerve section ; Neurofilaments ; Neurofibrils
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    Notes: Summary Sensory neurons were examined in spinal ganglia of the rat 1 to 55 days after section of the plexus brachialis nerves. Only “light” neurons of the type A were investigated. Maximal reaction to axotomy was found 7 to 14 days after the operation. The majority of the axotomized perikarya developed central chromatolysis. In such neurons, Nissl bodies virtually disappeared from the central area of the neuron and formed a more or less continuous zone at the cell circumference. The cytocentrum became filled with large numbers of mitochondria, dense bodies and other organelles. Neurofilaments and microtubules were disarranged and ran at random among the accumulated particles. Microtubules were often more prominent in chromatolytic areas than neurofilaments. Both these organelles were rare in the peripheral areas filled with massed Nissl substance. Part of the neurons that did not show typical chromatolysis contained increased numbers of neurofilaments among Nissl bodies dispersed throughout the cytoplasm. Neurofilaments were roughly arrayed in bundles up to several microns wide; they were linked by cross-bridges and separated by distances of about 500 Å. Microtubules were rarely found in the filamentous areas. However, they were numerous in the axon hillock and in the initial segment where they formed fascicles similar to those described in normal neurons of other types. During the period from 14 to 55 days after axotomy, many perikarya recovering from chromatolysis contained enlarged bundles of neurofilaments with occasional microtubules among the restored Nissl bodies. Mean diameters of sensory neurons, measured 7 to 55 days after axotomy, in no instance exceeded those of contralateral control neurons. It thus appears that sensory perikarya do not increase in size either during the chromatolytic process or during the period of recovery.
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    Cell & tissue research 116 (1971), S. 136-150 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Rat ; Sex difference ; ACTH ; Electron microscopy
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    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Nebennierenrinde von 178 Sprague-Dawley-Ratten wurde elektronenmikroskopisch von der 1.–12. Lebenswoche unter Normalbedingungen sowie nach s.c. Injektion von 3 IE ACTH/100 g Körpergewicht innerhalb von 2 min — 24 Std untersucht. Ab der 5. Lebenswoche unterscheiden sich die Nebennieren von Weibchen im Bereich der äußeren Zona fasciculata durch Kernvergrößerung, größere Mitochondrien und kleindisperse Liposomen von denen der Männchen. Zyklusbedingte Schwankungen in der Ultrastruktur der weiblichen Nebennierenrinde bestehen nicht. Nach ACTH-Applikation nähert sich das Nebennierenbild des Männchen innerhalb von 30 min dem des unbehandelten Weibchens. Außerdem kommt es bei beiden Geschlechtern durch ACTH zu einer Dispersion und Reduktion der Liposomen, Vergrößerung des Golgiapparates und der Zellkerne, Ausweitung des endoplasmatischen Retikulums und Vermehrung der Mikrovilli. Der Geschlechtsdimorphismus wird funktionell erklärt.
    Notes: Summary 178 Sprague-Dawley-rats were studied by electron microscopy from the 1st to the 12th week of life under normal conditions and after s. c. injection of 3 I. U. ACTH/100 gbodyweight from 2 min to 24 hours. Beginning with the 5th week of life females differ from males by small dispersed liposomes and enlarged nuclei and mitochondria in the outer z. fasciculata. There is no change in the ultrastructure of the female adrenal cortex depending on the sexual cycle. After application of ACTH the adrenal cortex of males assimilates to the untreated females within 30 min. After ACTH-application both sexes show dispersion and reduction of liposomes, dilation of endoplasmatic reticulum, increasement of microvilli and enlargement of the Golgi apparatus. The sex-dimorphism is interpreted by functional differences.
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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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    Cell & tissue research 119 (1971), S. 334-354 
    ISSN: 1432-0878
    Keywords: Fat absorption ; Small intestine ; Rat ; Micropinocytosis ; Circadian rhythm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die vorliegende Untersuchung will klären, welche Rolle die Mikropinocytose bei der Fettresorption spielt und ob die Fettresorption tagesrhythmische Schwankungen aufweist. Zu diesem Zweck wurde Fett zu verschiedenen Tages- und Nachtzeiten in abgebundene Jejunumabschnitte von Ratten injiziert, das Darmgewebe in verschiedenen Abständen licht- und elektronenmikroskopisch untersucht und die Zahl der mikropinocytotischen Invaginationen der Enterocyten bestimmt. Folgende Resultate wurden erzielt: Die Häufigkeit der Mikropinocytose (mikropinocytotische Invaginationen/100 Mikrovilli) beträgt bei Hungertieren 4,78, bei Normaltieren 5,06, 1 min nach Gabe von Mazolachymus 3,55, 1/16 m NaCl-Lösung 4,37, Butterschmalz 5,50, Rindertalg 7,16, Schweineschmalz 7,66 und Mazola 9,25; 2 1/2 min nach Mazolagabe 8,23, nach 5 min 7,67, nach 10 min 6,76. Zwischen 10 und 15 min wird der Ausgangswert erreicht. Aufgrund statistischer Auswertung der Befunde wird geschlossen, daß Fett vor allem in den Frühstadien der Fettresorption durch Mikropinocytose aufgenommen werden könnte. Ferner zeigt sich, daß die Mikropinocytosehäufigkeit entscheidend von der chemischen Zusammensetzung und dem physikalischchemischen Zustand der verabreichten Fette beeinflußt werden dürfte. — Lichtmikroskopisch wurde nachgewiesen, daß die Fettresorption charakteristische, tagesrhythmische Schwankungen aufweist. Um 2.00 Uhr ist sie am stärksten, um 14.00 Uhr am geringsten. Es wird diskutiert, worauf die tagesrhythmischen Unterschiede zurückzuführen sind.
    Notes: Summary The present study attempts to elucidate (a) to what extent micropinocytosis is involved in the process of fat absorption and (b) whether fat absorption shows a circadian rhythm. For this purpose rats were given 0.1 to 0.15 ml of fat directly into the upper jejunum at various times of the day and night. 20 sec to 20 min after administration of fat small pieces of the jejunum were rapidly dissected out, the tissue examined by means of light- and electron microscopy, and the number of micropinocytotic pits occurring in the enterocytes during fat absorption was determined. The following results were obtained: The frequency of micropinocytosis (micropinocytotic pits/100 microvilli) is as follows: in starved rats 4.78, in normal rats 5.06, 1 min after administration of corn oil chyme 3.55, 1/16 m NaCl-solution 4.37, clarified butter 5.50, ox tallow 7.16, lard 7.66, corn oil 9.25; 2 1/2 min after administration of corn oil 8.23, after 5 min 7.67, and after 10 min 6.76. Between 10 and 15 min the number of micropinocytotic pits reverses to normal. From statistical analysis of the results it is concluded that micropinocytosis can play a significant role in the early stages of fat absorption. The experiments show in addition that micropinocytosis is greatly influenced by the chemical composition and the physico-chemical state of the administered fat.—Light microscopic studies indicate that fat absorption varies considerably during the 24 hr period. The highest absorption was found at 2 a.m., the lowest at 2 p.m.
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    Cell & tissue research 124 (1972), S. 1-11 
    ISSN: 1432-0878
    Keywords: Spermiogenesis ; Rat ; Spermatids ; Manchette ; Microtubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The manchette or caudal tube has been examined in Stage 14 rat spermatids. The microtubules of the caudal tube have been found to be partially sheathed by smooth endoplasmic reticulum which appears to be continuous with the outer nuclear membrane of the redundant nuclear envelope. The microtubules in caudal regions of the manchette have been noted to be interconnected by links of unusual size and morphology. It is suggested that the caudal tube consists at this stage of development of two structures, membrane and microtubules and that the links between the microtubules appear to play a role in the structural order noted in the position of the tubules of the manchette. The possible significance of these links in relation to motility is discussed.
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    Cell & tissue research 124 (1972), S. 311-319 
    ISSN: 1432-0878
    Keywords: Median eminence ; Rat ; Neurovascular contacts ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the median eminence of the rat axons of the supraoptic-paraventricular-hypophyseal tract with elementary neurosecretory granules (150–200 mμ) traverse the internal zone. Terminals containing dense core vesicles 60–120 mμ in diameter end on the portal capillaries of the median eminence. A unique organisation of the primary portal capillaries is shown. Endothelial cells have many fenestrae. The pericapillary space has numerous extensions all of which represent a special zone around the endothelial tube. The fine structural organisation and function of the neurovascular contacts in the median eminence are discussed.
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    Cell & tissue research 126 (1972), S. 41-52 
    ISSN: 1432-0878
    Keywords: Pituitary ; Rat ; Oestradiol influence ; STH-cells ; Leucine incorporation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pituitaries of male and female rats neonatally treated with oestradiol dipropionate were examined with light and electron microscopy, disc electrophoresis and in vitro C14-leucine incorporation. Single dose of oestradiol administered shortly after birth to male rats has an prolonged stimulative effect on LTH synthesis and release. This is expressed in the cell hypertrophy, proliferation of ER, increase of corresponding band density and higher rate of 14C-leucine incorporation. In females this effect was less pronounced. STH cell in the treated male pituitaries were degranulated, corresponding hormone band density significantly lowered and incorporation of 14C-leucine was reduced. This could be considered as an inhibitory effect of oestradiol on STH synthesis and release. Such effect was more expressed two than four months after treatment and is more pronounced in male than in female rats.
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    Cell & tissue research 126 (1972), S. 421-430 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Rat ; Growth ; Sex-dimorphism ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Anhand des Verlaufs des 3H-Index und der Mitoserate in Anhängigkeit vom Lebensalter wurde die Proliferationsaktivität in den Zonen der Nebennierenrinde untersucht. 84 SPF-Ratten erhielten 2 μCi/g 3H-Thymidin i.p.; der Untersuchungszeitraum erstreckte sich vom 18. Trächtigkeitstag bis zur 12. Lebenswoche. Alle Zonen zeigten in der Rangfolge Glomerulosa — Fasciculata — Reticularis eine Abnahme DNS-synthetisierender Zellkerne. Geschlechtsspezifische Unterschiede im Ausmaß der Proliferationsaktivität konnten zu keiner Zeit nachgewiesen werden. Aus der Dissoziation der Kurven des 3H-Index und der Mitoserate bei vergleichbaren DNS-Syntheseraten wird auf eine Änderung der G2-Phase des Generationszyklus der NNR-Zellen in der teilexponentiellen Wachstumsphase geschlossen.
    Notes: Summary In 84 SPF-rats the poliferative activity of the adrenal cortical cells was studied from the 18th day of pregnancy up to 12 weeks post partum. Rats were given 2 μC/g tritiated thymidine and killed 1 hour thereafter. It was shown that there was no sex-related difference in the degree of proliferation that could explain the sexual dimorphism in adrenal weights. In all cortical zones a decrease in the number of labeled cells was seen during the obvservation period. The highest percentage of labeled cells was found in the glomerulosa. There exists no parallelism of the mitotic and labeling index, which gives evidence for a change in length of the G2-phase of the cell generation cycle.
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    Cell & tissue research 127 (1972), S. 483-491 
    ISSN: 1432-0878
    Keywords: Lateral preoptic area ; Hypothalamus ; Rat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The arcuate nucleus, median eminence, and the lateral preoptic area from the brains of aldehyde-perfused male and female rats were examined by electron microscopy. In the lateral preoptic area, three neuronal types are described: a small light neuron, a larger light one, and a dark neuron resembling the larger light one in size and nuclear shape. Many myelinated axons are interposed among single neurons or neuronal pairs. The relationship of structures to each other is discussed. Several observations not previously reported are illustrated from tissue of the arcuate nucleus and median eminence.
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    Cell & tissue research 124 (1972), S. 354-366 
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    Keywords: Hippocampal region ; Rat ; Monoamine oxidase ; Chemoarchitectonics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The distribution of monoamine oxidase (MAO) in the hippocampal region of the rat has been studied in cryostat sections with the tryptamine-tetrazolium method of Glenner et al. 2. The staining pattern was rather diffuse as compared with the distribution of MAO in the guinea pig and of other enzymes in the rat hippocampal region. 3. However, there were differences in enzyme activity between different areas and layers which could be correlated to some degree with results obtained with other methods, e.g., silver impregnation, catecholamines, and acetylcholinesterase.
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    Cell & tissue research 128 (1972), S. 406-425 
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    Keywords: Parafollicular Cells ; Rat ; Normalcalcemia ; Vitamin D2 ; Electronmicroscopy ; Histochemical fluorescence method
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary Thyroid parafollicular cells of normocalcemic and vitamin D2-treated rats were investigated by electron microscopy and with the histochemical fluorescence technique of Hillarp and Falck. Administration of high doses of vitamin D2 caused hypercalcemia and an extensive degranulation of the parafollicular cells. The formation and storage of monoamines in granulated and degranulated parafollicular cells was investigated by fluorescence microscopy after injection of monoamine precursors (DOPA, 5-HTP), alone or in combination with Ro 4-4602, nialamide or reserpine. No fluorescence was observed in parafollicular cells of untreated rats. l-DOPA and l-5-HTP (but not the corresponding D-amino acids) were taken up by a process closely linked to the decarboxylation of the amino acids to the corresponding amines (dopamine and 5-hydroxytryptamine). Treatment with vitamin D2 did not seem to affect the formation of amines in the parafollicular cells or the formation and storage of amines in other cell systems investigated. The amine itself (dopamine) was not taken up by the parafollicular cells. In normocalcemic rats, the amine formed was retained in the cytoplasm of the parafollicular cells by a partially reserpine-resistant mechanism. The storage of amines is concluded to occur in association with the calcitonin-containing granules. In parafollicular cells of vitamin D2-treated rats, a certain amount of amine was bound in the cytoplasm in the absence of typical granules. As a considerable amount of calcitonin is known to remain in the thyroid of vitamin D2-treated rats, the present observations may indicate an association between the amine and the polypeptide hormone calcitonin, whether the latter is confined to typical granules or not.
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  • 72
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    Cell & tissue research 129 (1972), S. 471-499 
    ISSN: 1432-0878
    Keywords: Cardiac muscle cells ; Rat ; Mitotic division ; Myofibril changes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the myocyte at all phases of mitosis as well as of early postmitotic cells has been studied in the myocardia of 14- and 18-day rat embryos and 5- and 7-day old rats. The myofibrils remain unchanged up to the late prophase. In prometaphase the majority of Z-disks in embryo myocyte myofibrils and considerable part of these disks in myofibrils of suckling rats are drastically disintegrated. This is followed by a progressive isolation and scattering of the myofilament bundles and of the whole sarcomeres during the subsequent phases of mitosis. Thick myofilaments seem to be unchanged but thin ones become frequently poorly outlined (mainly in embryos). The sarcoplasmic reticulum, including its typically differentiated subsarcolemmal cisternae, exhibits relatively few changes during mitosis. In the early postmitotic period there is a gradual restoration of contrast-rich Z-bands, interconnecting the previously isolated sarcomeres. Patterns of this process have much in common with early stages of myofibrillogenesis (appearance of subsarcolemmal “Z-bodies”, formation of skeins of thin filaments etc.). The cleavage furrow formation is either absent or considerably retarded up to the postmitotic period. Behaviour of some other organelles during myocyte mitosis has been described. Possible mechanisms and significance of the observed phenomena are discussed.
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  • 73
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    Cell & tissue research 130 (1972), S. 58-69 
    ISSN: 1432-0878
    Keywords: Infundibulum ; Rat ; Ependymal and glial cells ; Inclusions ; Neuroglial synapses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Zahlreiche Ependymzellen des Recessus infundibularis und Gliazellen der Zona externa besitzen Fortsätze, die bis an den perivaskulären Raum der Kapillarschlingen des Portalplexus heranreichen. Die Ultrastruktur dieser Gefäßfortsätze wird beschrieben. Sie können verschiedenartige Einschlüsse enthalten: 1. große, runde osmiophile Einschlüsse (0,5–2 μ im Durchmesser), die als „lipid inclusions“ bezeichnet werden; 2. unregelmäßig geformte, granuläre Einschlüsse mit gleichmäßiger Elektronendichte (500 bis 2000 Å im Durchmesser); 3. rundliche Granula mit einem hellen Zentrum und ringartig um dieses Zentrum gelagerten elektronendichten Körnchen (1200–1600 Å im Durchmesser). Der letztgenannte Granulatyp scheint ein charakteristisches Merkmal der Gefäßfortsätze in der Zona externa der Wistar-Ratte zu sein. Meist häufen sich die Körnchen gemeinsam mit den anderen beschriebenen Einschlüssen in den kolbenförmigen Endigungen der Gefäßfortsätze. Exocytosevorgänge an der dem perivaskulären Raum zugewandten Oberflächenmembran der Fortsätze weisen auf eine Abgabe von Substanzen an die Blutbahn hin. Neurogliöse Synapsen finden sich im Infundibulum vorwiegend zwischen Nervenfasern des Tractus tuberohypophyseus und Gefäßfortsätzen der Ependym- und Gliazellen. Der synaptische Spalt enthält häufig fädige oder körnige Strukturen. Solche Partikel finden sich zusammen mit tubulären oder vesikulären Membranprofilen auch im synapsennahen Bereich des Glia- oder Ependymfortsatzes. Die funktionelle Bedeutung dieser Synapsen insbesondere für die Abgabe neuronaler Substanzen wird diskutiert.
    Notes: Summary Many ependymal cells of the infundibular recess and many glial cells of the external layer send their processes to the perivascular space of capillary loops of the portal plexus. The ultrastructure of these vascular processes is described. They may contain various inclusions: (1) large, osmiophilic globules (0,5–2 μ in diameter), mostly termed “lipid inclusions”; (2) irregularly formed, granular inclusions with an evenly distributed content (500–2000 Å in diameter); (3) circular granules comprising an electron-lucent centre surrounded by an annular wall of electron-dense particles (1200–1600 Å in diameter). This type of granule seems to be characteristic for the vascular processes in the external layer of the Wistar rat. Frequently accumulations of these granules are found together with other inclusions in the widened end-feet of the vascular processes. The occurrence of exocytosis at the perivascular surface membrane of the vascular processes indicates a release of substances into the blood. Neuro-glial synapses in the infundibulum are mainly found between nerve fibres of the tuberohypophyseal tract and the vascular end-feet of ependymal and glial cells. The synaptic cleft often contains filamentous or granular material. Together with tubular and vesicular membrane profiles such particles are also found in the postsynaptic area of the ependymal and glial processes. The functional significance of these contacts is discussed particularly with respect to the release of neuronal substances.
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  • 74
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    Cell & tissue research 129 (1972), S. 92-113 
    ISSN: 1432-0878
    Keywords: Neurosecretion ; Neurohypophysis ; Neurosecretory granule ; Rat ; Membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neurosecretory granules (NSG) of rat posterior pituitary glands were prepared by differential centrifugation techniques mainly according to the procedure as described by Barer, Heller and Lederis (1963). As revealed by electron microscopy, the recovery of neurophysin and the contents of enzymes, purified NSG were obtained in a pellet at 30 000 g/60 min (0.44 M sucrose). Eighteen h after injection of (35S) cysteine into the supraoptic nucleus 60% of the recovered radioactivity in the neural lobe was found in the NSG, whereas 20% was found in the final supernatant (100 000 g/120 min). Sixteen days after injection the NSG and the final supernatant fraction contained fairly equal amount of (35S) cysteine (approximately 40%). It is suggested that after a period of intragranular maturation neurophysin is extruded into an extragranular pool of neurosecretory material. With the use of conventional polyacrylamide-gel electrophoresis it was shown that the predominating proportion of radioactivity in the NSG after a hypothalamic injection of (35S) cysteine was located within the neurophysin fraction A and in fraction B. Fraction B is suggested to be partly bound to the NSG membranes. When the NSG soluble and NSG insoluble proteins, obtained after lysis of NSG, were separated on polyacrylamide gels in the presence of sodium dodecylsulphate, the highly radioactive soluble protein was shown to consist of two components with average molecular weights of 12 300 and 14 600. Most of the proteins in the lysate were found in the NSG membranes, though less radioactive. A component with a mol.wt. of 37 000 was enriched in the membrane fraction. At longer times after isotope injection the high mol.wt. proteins, particularly those of the NSG membranes, contained increased amounts of radioactivity.
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  • 75
    ISSN: 1432-0878
    Keywords: Kidney ; Rat ; Actin- and myosin-like filaments ; Tubule and interstitial cells ; Electron microscopy
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    Notes: Summary By electron microscopy, the prominent bundles of filaments occurring in the basal part of proximal and distal tubule cells and in interstitial cells of rat kidney cortex were studied in cells fixed by vascular perfusion, in glycerol-extracted cells and in glycerol-extracted cells treated with heavy meromyosin (HMM). The studies of perfusion-fixed tissue showed that the proximal tubule cells contained in their most basal part filamentous bundles oriented transversely around the tubule. The bundles consisted of trightly packed thin filaments (50–80 Å in diameter). Similar but less prominent bundles were found in distal tubule cells and in interstitial cells. The dimension of these filaments was similar to that of actin filaments and their insertion in the basal cell membrane of the tubule epithelial cells resembled the insertion of actin filaments in the cell membrane of smooth muscle cells. The studies on glycerol-extracted cells revealed that some tubule cells contained two types of filaments (60–80 Å and 130–170 Å in diameter) located side by side in the basal filamentous bundles. The dimension of the thick filaments corresponds well to the values for myosin filaments in glycerinated smooth and skeletal muscle. The studies on HMM-reacted renal tissue revealed that the thin filaments (60–80 Å) described in tubule and interstitial cells are probably actin filaments, as they formed characteristic arrowhead complexes morphologically indistinguishable from the complexes of HMM with actin filaments in smooth and striated muscle cells. Our results provide strong evidence that a two-filament contractile system, based on interaction of actin and myosin filaments, exists in renal tubule and interstitial cells. As a hypothesis it is proposed that it is changes in tonus of the basal filamentous system in the proximal tubule cells which stabilize the intratubular pressure, possibly via angiotensin.
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  • 76
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    Cell & tissue research 140 (1973), S. 473-479 
    ISSN: 1432-0878
    Keywords: Testicular feminization ; Rat ; Leydig cells ; Sterility ; Androgens, Steroids ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary The interstitial cells of the pseudohermaphrodite rat testis are both hypertrophic and hyperplastic. The cytoplasm is characterized by smooth endoplasmic reticulum which is abundant and variable in form. Mitochondria are numerous and large with tubular cristae and occasional inclusions. Structural features of the Leydig cells indicate potential for increased steroid synthesis. The presence of large numbers of mast cells in the intertubular area is confirmed. Small seminiferous tubules lack advanced germinal elements. Additional connective tissue and myoepithelial layers produce a thickening of the limiting membrane. Some myoepithelial cells are atypical with an electron translucent cytoplasm and nuclei with dense peripheral chromatin. No spermatogenic cells beyond the cap phase of the spermatid are observed. The cytoplasm of Sertoli cells contains large lipid droplets and degenerating germ cells.
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  • 77
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    Keywords: C cells ; Thyroid ; Rat ; Ultimobranchial origin ; Differentiation
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    Description / Table of Contents: Résumé Nos observations confirment l'origine ultimobranchiale des cellules C de la thyroïde du rat. L'évolution des corps ultimobranchiaux (C.U.B.) a été étudiée à partir du 16ème jour de gestation, stade où ils fusionnent avec l'ébauche thyroïdienne. Dès le 17ème jour, les premières cellules C se différencient dans le C.U.B. inclus dans la thyroïde. Au 18ème jour, elles sont plus nombreuses et commencent à se disperser dans les cordons thyroïdiens. La migration des cellules C est particulièrement importante au 19ème jour. A partir du 20ème jour, les signes d'activité sécrétoire s'intensifient très nettement. A la fin de la vie foetale, les cellules C sont comparables aux cellules C adultes. La differenciation des cellules parathyroïdiennes précède nettement celle des cellules C.
    Notes: Summary Our observations confirm the ultimobranchial origin of the C cells of the rat thyroid. We studied the development of the ultimobranchial body from the 16th day of pregnancy, when there is fusion with the thyroidian anlage, onwards. As early as the 17th day, the first C cells differentiate in the ultimobranchial body which is included into the thyroid. On the 18th day, they are more numerous and start to scatter throughout the thyroidian cords. The migration of the C cells is especially obvious on the 19th day. From the 20th day onwards, there is marked increase in secretory activity. At the end of the foetal life, the C cells resemble those of the adult. The differentiation of the parathyroid cells significantly precedes that of the C cells.
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    Cell & tissue research 146 (1973), S. 463-471 
    ISSN: 1432-0878
    Keywords: Neurosecretory granule ; Pars nervosa ; Rat ; Morphometry
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    Notes: Summary The distribution of the diameters of the neurosecretory granules in the rat pars nervosa (measured from electron micrographs taken at 40 000 × ) was compared among axons by nonparametric statistical methods and the axons were classified into five groups with median granule diameters of 143, 155, 167, 180 and 193 nm. We suggested that these five axon types carried different secretory substances contained in the pars nervosa.
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  • 79
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    Cell & tissue research 148 (1974), S. 203-211 
    ISSN: 1432-0878
    Keywords: Hypothalamus ; Rat ; Supraoptic nucleus ; Ultrastructure ; Somatic spines
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary Electron microscopic studies of ultrathin serial sections of the perikarya and adjacent neuropil of neurons of the supraoptic nucleus (SON) of the adult male rat revealed varying forms of two types of somatic spines. One type forms synapses with axons passing the cell, the other, without synapses, appears to serve as a buttress or clasp for adjacent neuronal and glial processes. The synapse-bearing spines lack the usual spine apparatus but contain the flocculent substance often seen in spines. The other spines do not exhibit either of these structures. These somatic spines were also seen in Golgi impregnated preparations but the types could not be distinguished. Certain axons synapse either on a somatic spine of the perikarya or penetrate the glial sheath of the neuron and synapse, usually repeatedly, on the soma in an en passant manner.
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    Cell & tissue research 148 (1974), S. 371-379 
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    Keywords: Pineal gland ; Rat ; Electric coupling areas ; Freeze-etching
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    Notes: Summary The pineal glands of Wistar rats were fixed in glutaraldehyde and prepared by the freeze-etching technique. With regard to the form and internal structure of pineal cells this technique has revealed nothing essentially new. Synaptic ribbons are very rarely found. A regular diagonal arrangement of membrane attached particles between the Schwann cell and the axon of an autonomic nerve terminal was observed. Three types of contact areas between pineal cells are described. In the first two types, which occur more frequently, the diameter of the area varied from 1000 to 2500 Å, with irregularly aggregated membrane associated particles. The third type, larger but less frequently found, has a surface area of 0.4 μm2 and much more regularly distributed membrane associated particles (ø 88 Å). These contact areas can be considered to be electric coupling areas between pineal cells.
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  • 81
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    Cell & tissue research 107 (1970), S. 447-453 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Rat ; Trypsin-dissociation ; ACTH stimulation ; Ultrastructure
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    Notes: Summary Electron micrographs of trypsin-dissociated rat adrenal showed predominantly intact rounded cells without internal damage. The population contained cells from the glomerular, intermediary and fascicular zones with cells from the zona fasciculata predominant. The presence or absence of cells from the reticular zone could not be determined. Cells from the medullary zone were absent. The addition of adrenocorticotropic hormone (ACTH) to the cellular suspension for 2 hours produced corticosterone. However, these stimulated cells did not display any significant ultrastructural change.
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    Cell & tissue research 108 (1970), S. 487-500 
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Residual lumen ; Epithelial cells ; Fine structure ; Rat
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    Notes: Summary Histology, enzyme histochemistry, and electron microscopy of the epithelium covering the rat pituitary residual lumen was studied. The anterior and posterior epithelium have similar histological and histochemical appearance, although the posterior epithelium shows stronger enzyme reactions for an esterase and many dehydrogenases. Electron microscopic studies reveal that both epithelia form a continuous lining. Anterior epithelium is in immediate contact with the interstitial spaces of the anterior lobe, while the posterior epithelium is separated from the intermediate lobe by a continuous basement lamina. The cytological features of both epithelia are also remarkably similar with scanty rough-surfaced endoplasmic reticulum, inconspicuous Golgi apparatus, round or oval mitochondria, and moderate number of lysosomal bodies. The apical surface of these cells is covered by microvilli and in some, especially posterior epithelial cells, by numerous cilia. Anterior epithelial cells and the apical portions of the posterior epithelial cells contain a number of large vacuoles with material possibly related to the colloid within the residual lumen. Electron microscopic findings suggest that both epithelia are possibly active in transfer and/or disposal of the colloid material rather than being secretory themselves. Enzyme histochemical findings support the hypothesis of an active role of these cells in metabolic processes related to phagocytosis. Based on these observations the colloid seems to be the product of the anterior lobe function.
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  • 83
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    Cell & tissue research 110 (1970), S. 559-568 
    ISSN: 1432-0878
    Keywords: Cerebral cortex ; Rat ; Synapses ; Postnatal ; Quantitation
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    Notes: Summary Quantitation of synapses at different postnatal ages has been undertaken in the cerebral cortex of the rat. In this study axial ratios of presynaptic bags, proportion of cortex occupied by presynaptic bags and numbers of synapses per unit volume of cortex have been estimated. Observations on synaptic vesicle packing densities have also been made. Synaptic bags become increasingly spherical up to 7 days of age and become more elongated thereafter. The proportion of cortex occupied by presynaptic bags increases rapidly up to 7 days of age and then at a decelerated rate up to maturity. The number of synapses per unit volume increases slowly over the first four days after which there is a rapid increase to 14 days, followed by a decelerated rate. The average presynaptic bag shows marked changes in volume with increasing age which indicate the probability of two stages of synaptic development. This two stage development is further reflected in the estimates on vesicle packing densities. The implications of the results are discussed in relationship to changes in functional activity of the cortex during postnatal development.
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  • 84
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    Cell & tissue research 110 (1970), S. 569-587 
    ISSN: 1432-0878
    Keywords: Subtotal Pancreatectomy ; Rat ; Islet Regeneration ; Excretory Duct System
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Männliche Ratten wurden bei einem Gewicht von 80–100 g subtotal pankreatektomiert (5% Rest) und zu verschiedenen Zeitpunkten nach der Operation abgetötet. Bei diesen wie bei unbehandelten Kontrolltieren wurde die Neubildung von Inselgewebe aus dem exkretorischen Gangsystem elektronenmikroskopisch untersucht. — Es konnte gezeigt werden, daß die Inselneubildung von Gangzellen ausgeht, welche ein auffallend helles Zytoplasma besitzen und samt ihren Kernen größer und abgerundeter sind als ihre Nachbarzellen. Diese Zellen wandern vom Lumen ab, wobei die entstehende Lücke zum Lumen zu jeweils durch eine seitliche Ausdehnung des Zytoplasmas benachbarter Gangzellen geschlossen wird. Die abgewanderten hellen Zellen, die mit den lichtmikroskopisch beschriebenen „trüben Zellen“ identisch sein dürften, haben die Fähigkeit, sich zu Alpha-oder Beta-Zellen zu differenzieren. Dabei werden sie größer und das Zytoplasma dunkler. Sie behalten aber gleichzeitig einige Besonderheiten, die auf ihre Herkunft hinweisen. Die Regeneration des Inselgewebes, die vorwiegend von den zentroacinären Zellen ausgeht, setzt bald nach der Operation stark ein, schwächt sich dann aber kontinuierlich ab. In den immer ineffektiver werdenden Regenerationsvorgang werden zunehmend größere Gangabschnitte einbezogen. Die weitgehende Erschöpfung der Regenerationsfähigkeit fällt mit dem Auftreten eines manifesten Diabetes zwischen dem 40. und 60. Tag p.op. zusammen.
    Notes: Summary Male rats were subtotally pancreatectomized at a weight of 80–100 g according to the method of Foglia (5% of the total pancreas remaining). The animals were killed at different intervals after. In these rats, as well as in healthy controls, the new formation of islets out of the excretory duct system was studied by electron microscopy. Obviously the new formation of islets takes origin from certain cells of the ductular system which show a light cytoplasm and are larger and rounder than their neighbouring cells. The latter goes for their nuclei, too, even to a larger degree. These light cells migrate away from the ductular lumen and the gaps resulting from this are closed by long and thin processes of the cytoplasm of their neighbouring duct cells coming in contact with each other. The cells having migrated away seem to have an ability to differentiate into alphaor beta-cells. Most probably they are identical with the “trübe Zellen” described by light-microscopists. The higher the degree of differentiation in these cells is, the darker becomes their cytoplasm. But they still keep for some time morphological aspects indicating their origin from ductular cells. An intense regeneration of islet tissue starts soon after the operation from the centroacinar cells but it decreases continuously after. As the process of islet regeneration becomes more and more ineffective, an increasing number of larger excretory ducts are involved in it. The exhaustion of the ability for regeneration is correlated exactly in time with the onset of a manifest diabetes between the 40 th and 60 th day after operation.
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    Cell & tissue research 111 (1970), S. 364-378 
    ISSN: 1432-0878
    Keywords: Rat ; Oocyte maturation ; in vitro studies
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    Topics: Biology , Medicine
    Notes: Summary After cultivation in a modified Trowell-system (organ ciilture) oocytes of 12- to 40-day-old rats were studied under the light and electron microscope. The cultivation period was 72 hrs. Egg cells from primary and early secondary follicles which are characterized by the lack of a zona pellucida and by one or at most two very large Golgi's complexes located near the nucleus do not show any alterations. The other egg cells are characterized by membrane packages which can otherwise only be observed in mature egg cells right before or after the ovulation. Meiotic processes or the formation of polar bodies are only seldom to be seen. These egg cells are surrounded by a thick zona pellucida. From these findings the following conclusions can be drawn: 1. In organ cultures meiotic processes are prevented by the inhibitory influence of follicle cells (Foote and Thibault, 1969). 2. A cytoplasmic maturation proceeds independently. 3. In-vivo an inhibitory factor influences the cytoplasmic maturation. This inhibition is not observed in the organ culture. Thus we can be sure that it develops outside the ovary. 4. The synthesis of the zona pellucida continues in-vitro.
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  • 86
    ISSN: 1432-0878
    Keywords: Substantia nigra ; Rat ; Incorparation of 3H-Dopamine, 3H-Serotonin and 3H-Norepinephrine ; Axo-dendritic Synapses ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In autoradiographies of substantia nigra in rat, it has been observed that after intraventricular injections of 3H-dopamine and 3H-norepinephrine respectively the silvergrains are accumulated in nigra neurons and their dendritic branches. The incorporation was more pronounced in the case of 3H-norepinephrine than 3H-dopamine. This seems to indicate that exogenous norepinephrine may have stronger affinity to nigra neurons and their dendrites than exogenous dopamine. In addition, some 3H-dopamine and 3H-norepinephrine labelled nerve terminals were observed in axo-dendritic synapses. In contrast to these data, 3H-5HTP and 3H-5HT administration showed almost all silver grains accumulated in the neuropil when observed in light microscopic autoradiography. Electron micrographs further reveal that the incorporation of 3H-5HTP and 3H-5HT was mostly within axo-dendritic boutons with more frequent dense core vesicles. These data again strongly suggest that substantia nigra receives a large number of serotoninergic fibres forming axo-dendritic synapses which may play an important role in modulation of substantia nigra function.
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    Cell & tissue research 114 (1971), S. 271-280 
    ISSN: 1432-0878
    Keywords: Thymus ; Rat ; Involution ; Reticulum-Cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung 1. Entodermale Thymus-Retikulumzellen neugeborener Wistar-Ratten enthalten häufig helle Vesikel mit enger räumlicher Beziehung zum Golgi-Apparat. Bei 13 Monate alten Ratten fehlen diese Vesikel. 2. Die Tatsache, daß die Häufigkeit heller Vesikel mit fortschreitendem Lebensalter abnimmt, findet ihre Parallele in der von anderer Seite getroffenen Feststellung, daß die Bildung eines humoralen Faktors im Thymus im Laufe der Zeit eingeschränkt wird. 3. Diese Koinzidenz läßt an die Möglichkeit denken, die hellen Vesikel könnten ein morphologisches Äquivalent der Bildung eines Thymuswirkstoffes sein. 4. In entodermalen Thymus-Retikulumzellen 13 Monate alter Ratten finden sich große Vakuolen mit granulärem Inhalt. Ihre Bildung beginnt schon vor der Thymusinvolution. Sie entstehen wahrscheinlich durch Phagozytose oder Aufnahme zelleigenen Materials, das nicht weiter abbaufähig ist. 5. Da diese Einschlüsse mit fortgesetzem Alter an Zahl und Größe zunehmen, scheinen sie als Ausdruck einer Beeinträchtigung der Stoffwechselvorgänge im Zytoplasma ein erstes morphologisch faßbares Symptom der frühzeitigen physiologischen Involution des Thymus zu sein.
    Notes: Summary 1. Entodermal reticulum cells of new born Wistar rats frequently contain clear vesicles with close connection to the Golgifield. These vesicles do not occur in reticulum cells of 13 months old rats. 2. The frequency of these clear vesicles decreases with advancing age obviously in the same way as the production of a humoral thymic factor reported by several investigators. 3. This observation agrees with the hypothesis that the clear vesicles are the morphological equivalent of the production of a humoral thymus factor. 4. Entodermal reticulum cells of 13 months old Wistar rats contain large vacuoles filled with electron dense, granulated materials. The formation of these vacuoles starts already before the beginning of the thymus involution. Possibly they are produced by phagocytosis or necrobiosis and contain deposits of material that cannot undergo further degradation. 5. The increase of these vacuoles in number and size with advancing age may be considered as equivalent of the deterioration of metabolism responsible for early involution of the thymus.
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    Cell & tissue research 116 (1971), S. 61-69 
    ISSN: 1432-0878
    Keywords: Paraventricular nucleus ; Rat ; Types of neurons ; TRF-synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural aspects of the paraventricular nucleus and its neuropil are described in the normal rat. Two types of neurons can be distinguished morphologically. The first type contains numerous dense-core vesicles (mean diameter: 140 nm). The cisternae of the endoplasmic reticulum are arranged parallely at the periphery of the cell body. The second type of neuron contains a few dense-core vesicles (mean diameter: 75 nm) and the endoplasmic reticulum is randomly distributed in the cytoplasm. In the neuropil, two types of dense-core vesicles are observed in separated axons. The histogram of the distribution of their mean diameter clearly indicates a double population of vesicles. The signification of the second type of neuron in the paraventricular nucleus is discussed and its possible relation to TRF synthesis is evoked.
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    Cell & tissue research 116 (1971), S. 119-135 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Rat ; Sex difference ; Light microscopy ; Histometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung An 260 männlichen und weiblichen Sprague-Daweley-Ratten vom 0. Lebenstag bis zur 12. Lebenswoche wird die geschlechtsdifferente Entwicklung der Nebennierenrinde histologisch und histometrisch verfolgt. Von der 4. Lebenswoche an ist die weibliche Fasciculatazelle durch ein helles, fein-granuläres Cytoplasma ohne distinkt abgrenzbare Fettvakuolen ausgezeichnet, während beim Männchen in einem kompakten Cytoplasma zunehmend größere, deutlich begrenzte Vakuolen auftreten. Im Blindversuch gelingt aufgrund dieser Kriterien die Geschlechtsdiagnose mit großer Treffsicherheit. Nach histometrischen Untersuchungen sind die weiblichen Fasciculatakerne größer als die männlichen. Bei größerem Zellvolumen ist die Kernzahl/Flächeneinheit beim Weibchen von der Pubertät an kleiner. Die Glomerulosa und die inneren Rindenschichten zeigen keine Geschlechtsdifferenzen. Fermenthistochemisch ist eine Geschlechtsdifferenz nicht nachweisbar. Die relative Zellhypertrophie in der Fasciculata der weiblichen Nebennierenrinde ist das morphologische Äquivalent eines geschlechtsdifferenten Steroidmetabolismus bei der Ratte.
    Notes: Summary In 260 male and female Sprague-Dawley CD rats the sex dependent development of the adrenal cortex was studied histologically and by histometric procedures. Beginning in the 4th week of life the parenchymal cells in the fasciculata of the female animals are characterized by a light, finely granular cytoplasm without distinct lipid vacuoles. In the males, however, the cells show a dense, compact cytoplasm with clearly visible vacuoles increasing in size. In a blind test the sex diagnosis can be established with great accuracy. Histometrically the nuclei in the female fasciculata cells are larger than in the males. Furthermore, caused by a larger cell volume the number of nuclei per square unit is smaller in postpuberal females. The glomerulosa and the inner parts of the cortex do not show any sex differences, nor does enzyme histochemistry. The relative cellular hypertrophy in the fasciculata of the female adrenal cortex represents the morphologic equivalent of the sexual differences in the rats steroid metabolism.
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  • 90
    ISSN: 1432-0878
    Keywords: Nematosomes ; Subsynaptic web ; Microfilamentous cytoplasmic network ; Neurosecretory cells ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An electron microscope study of the rat supraoptic nucleus, substantia nigra, neostriatum and periventricular preoptic area demonstrates that nematosomes are present within the perikaryon of neurons located in these structures. The latter structure may be found in close association with the subsynaptic web of axosomatic synapses. Numerous micro-filaments fan out from the nematosome and link the latter organelle to the ribosomes, the cytoplasmic membranes and the plasma membrane thus establishing an interwoven filamentous cytoplasmic network. A possible close relationship between the nematosomes and the neurofilaments and neurotubules is discussed.
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  • 91
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    Cell & tissue research 118 (1971), S. 243-248 
    ISSN: 1432-0878
    Keywords: Arteriovenous anastomoses ; Valve mechanism ; Rat ; Skin of the paw
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung In der dorsalen Haut der Hinterpfoten von Ratten wurden Klappen am Abgang kleinerer Gefäße von großen Arterien beobachtet. Diese Arterien verlaufen in einer subkutanen, größere Gefäße und Nerven führenden Bindegewebsschichte über den Streckersehnen. Die kleineren Gefäße haben den Wandbau einer Vene und zweigen etwa im rechten Winkel von der Arterie ab. An ihrer Abgangsstelle ist neben den Klappen manchmal ein sphinkterartiger Muskelring ausgebildet. Diese Gefäßabschnitte werden für arterio-venöse Anastomosen gehalten und auf die Bedeutung solcher an dieser Stelle bisher nicht beschriebenen Verschlußeinrichtungen für die Regulation der Kurzschlüsse wird hingewiesen.
    Notes: Summary In the dorsal skin of the hindpaws of rats valves were observed at those sites where smaller vessels branched from larger arteries. These arteries run in a subcutaneous layer of connective tissue, which lies above the extensor tendons and in which the larger vessels and nerves are found. These smaller vessels, the walls of which resemble those of veins, were seen branching off at approximate right angles to their artery of origin. Besides the valves a sphincterlike muscle ring was observed in some cases at the point of branching. These vascular segments are held to be arteriovenous anastomoses. Such “locking devices” at these points have not been described until now and seem to be important in the regulation of arteriovenous shunts.
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  • 92
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    Cell & tissue research 121 (1971), S. 171-180 
    ISSN: 1432-0878
    Keywords: Nerve endings ; Epithelium ; Rat ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Im Anschluß an frühere lichtmikroskopisch erhobene Befunde (Silberimprägnation; 1924, 1928) weist der Verfasser durch elektronenmikroskopische Untersuchungen nach, daß durch die Interzellularspalten des Epithels (Schnauze der weißen Ratte) Nervenfasern hindurchziehen. Diese Nervenfäserchen, ihre Varikositäten und ihre Endknöpfchen liegen in den Spalten zwischen den Epithelzellen. Die Ultrastruktur der nackten, d.h. von Schwannschen Zellen nicht umhüllten terminalen Nervenfasern und ihrer Endigungen im Epithel wird beschrieben.
    Notes: Summary In addition to former light microscopical observations the author demonstrates electronmicroscopically that nerve fibers pass through the intercellular spaces of the epithelium. The nerve fibers, their varicosities and terminal bulbs lie within the spaces between the epithelial cells. The ultrastructure of the terminal nerve fibers in the epithelium is described.
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  • 93
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    Cell & tissue research 121 (1971), S. 292-300 
    ISSN: 1432-0878
    Keywords: Tissue Mast Cells ; Rat ; Regeneration ; Monocytes ; Peritoneal Exudates ; Cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Regeneration von Gewebsmastzellen wurde durch Untersuchungen von Peritonealexsudat erwachsener Ratten verfolgt, die häufigen Spülungen der Bauchhöhle unterworfen wurden. Innerhalb von 4–6 Tagen kommt es zu einer starken Vermehrung unreifer Gewebszellen. Die Ausbildung von Alcianblau-positiven unreifen Granula in ungranulierten Vorstufen benötigt etwa 6 Std. Die Ausbildung von Safranin-positiven reifen Granula vollzieht sich in 48 Std. Die Ergebnisse der zytochemischen Untersuchungen unreifer Mastzellvorstufen sprechen für eine monozytogene Entstehung der Gewebsmastzellen.
    Notes: Summary In adult rats, the regeneration of tissue mast cells in peritoneal exudates was studied by repeated peritoneal lavages. After 4–6 days, tissue mast cells appeared in great numbers in peritoneal exudates. Alcian blue positive granules were first noted at 6 hrs in agranular mast cell precursors. Maturation with accumulation of safraninpositive granules was complete after 48 hrs. The cytochemical reactions of the earliest tissue mast cell precursors suggest a monocytogenic origin of tissue mast cells.
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  • 94
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    Cell & tissue research 124 (1972), S. 1-11 
    ISSN: 1432-0878
    Keywords: Spermiogenesis ; Rat ; Spermatids ; Manchette ; Microtubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The manchette or caudal tube has been examined in Stage 14 rat spermatids. The microtubules of the caudal tube have been found to be partially sheathed by smooth endoplasmic reticulum which appears to be continuous with the outer nuclear membrane of the redundant nuclear envelope. The microtubules in caudal regions of the manchette have been noted to be interconnected by links of unusual size and morphology. It is suggested that the caudal tube consists at this stage of development of two structures, membrane and microtubules and that the links between the microtubules appear to play a role in the structural order noted in the position of the tubules of the manchette. The possible significance of these links in relation to motility is discussed.
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  • 95
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    Cell & tissue research 124 (1972), S. 217-229 
    ISSN: 1432-0878
    Keywords: Sensory axons ; Dorsal root ganglia ; Rat ; Ribosomes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the dorsal root ganglia of the rat, ribosomes were found not only in the initial segment, but they were also observed in the axoplasm of intraganglionar myelinated fibres and in the sensory portion of spinal nerves. Axons of seven-days-old rats contained more ribosomes than those of adult animals. The amount of particles decreased gradually from the initial segment trough intraganglionar internodes to the axons of spinal nerves. No ribosomes were found in axons of dorsal roots. In intraganglionar fibres, ribosomal particles were usually observed near the nodes of Ranvier, in the vicinity of Schmidt-Lantermann clefts and in axons near the Schwann cell nuclei. They were arranged in tetrads, pentads or in larger polysomes, and they were often observed adjacent to a group of mitochondria. The particles had invariably a stable size, their average diameters measuring 234 ± 2 × 197 ± 3 Å, which is practically equal to the diameters of 232 ± 2 × 203 ± 3 Å of ribosomes in the Schwann cell cytoplasm. These values fall within the range of diameters of ribosomes isolated from various cells of eukaryotic organisms as given in the literature. Since no other granular component of the cytoplasm has similarly stable dimensions, the measurements are considered to prove that the axonal particles described here are ribosomes.
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  • 96
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    Cell & tissue research 123 (1972), S. 356-368 
    ISSN: 1432-0878
    Keywords: Ependyma ; Brain ; Rat ; Glycogen-rich cells ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ependyma of the lateral ventricle of the rat brain was investigated at different ages from 20 days to adulthood. A particular cell type occurs in the external wall of the ventricle, where the proliferative subependymal layer is present. These cells found at all ages studied, are characterized by a high content of glycogen, and a structure different of typical ependymal cells. A large number of nerve endings is situated in close vicinity of these cells, either free in the ventricle lumen, or sometimes ensheathed in the cells. No synapse was found between these endings an the glycogen-rich cells. These glycogen-rich cells undergo several modifications with age: their glycogen content is reduced in the adult, and they acquire a few cilia and gliofilaments. It is suggested that they represent a transitory differentiation of the ependyma, functionally linked with the proliferative subependymal layer.
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  • 97
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    Cell & tissue research 127 (1972), S. 570-579 
    ISSN: 1432-0878
    Keywords: Sympathetic nerve fibres ; Rat ; 5-HT-cells ; Habenular region (Lamina intercalaris ; Medial habenular nucleus)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pineal gland of the rat is located near the brain surface and is via a slender stalk connected to lamina intercalaris which constitutes a cell formation between the habenular and posterior commissures, continuing to the subcommissural organ. The stalk and lamina intercalaris, like the pineal proper, exhibited a yellow, formaldehyde-induced fluorescence which showed the histochemical and pharmacological properties of 5-HT. All these structures were richly supplied with catecholamine-fluorescent nerves which could be further followed rostrally from lamina intercalaris, mixing with the non-fluorescent commissural fibres and stria terminalis, into the medial habenular nucleus in which they extensively supplied both blood vessels and non-fluorescent nerve cells. Cytospectrofluorometric and chemical analysis suggested that the fluorescent nerves stored noradrenaline. This was supported by the finding that they disappeared after bilateral cervical sympathectomy (as did the fluorescent nerves in the pineal complex). In the medial habenular nucleus also catecholamine-containing and 5-HT-containing nerves of central origin were present. The occurrence of a rich, peripheral sympathetic innervation in the medial habenular nucleus of the brain offers possibilities for a previously not observed sympathetic influence on this nucleus. Also the arrangement, and the apparent continuity of the sympathetic innervation in the pineal gland, the lamina intercalaris, and the medial habenular nucleus, suggests some functional interconnection or coordination between these structures.
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  • 98
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    Cell & tissue research 129 (1972), S. 114-139 
    ISSN: 1432-0878
    Keywords: Neurosecretion ; Pituitary gland ; Rat ; Neurophysin ; Vasopressin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The release of neurophysin from neural lobe tissue slices and isolated neurosecretory granules of the rat was studied at various time intervals after injection of (35S) cysteine into the supraoptic nucleus. For hours after isotope injection the release of radioactive neurophysin from neural lobe tissue was increased by depolarizing concentration of potassium in the presence of calcium ions. Fourteen and 30 days after isotope injection the release of radioactive neurophysin was relatively decreased in a medium of high potassium concentration which might be explained by the heterogeneity of the pool of neurophysin within the neural lobe. Four h after isotope injection the “spontaneous” release of neurophysin from neural lobe tissue was higher in dehydrated rats than in controls, and the neural lobes of these animals did not respond with an increased release of radioactive neurophysin when exposed to high potassium concentration. Eighteen h after isotope injection the predominating proportion of neurophysin-bound radioactivity was found in the neurosecretory granule fraction, whereas 14 days after injection a fairly equal amount of radioactivity was found in this fraction and in the “soluble” protein fraction. This indicates that with time an increasing amount of radioactive neurophysin passes from an intragranular to an extragranular pool. The spontaneous release of radioactive neurophysin from isolated neurosecretory granules was higher, and the increase of release upon exposure to an ATP-regenerating system was higher 14 days after isotope injection than 18 h after injection. This may imply that the neurosecretory material undergoes an intragranular “maturation” process to become more easily releasable. The release of radioactive neurophysin was inhibited in the presence of AMP and EDTA, which demonstrates the dependence of the release process of an ATPase and, probably, of calcium ions. Neurosecretory granules from dehydrated rats possessed a higher spontaneous release than those of control rats 18 h after injection, which may indicate an enhanced intragranular “maturation” process of the neurosecretory material due to osmotic stimulation.
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  • 99
    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Rat ; Fat droplets ; Fat resorption ; Quantitative electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Elektronenmikroskopisch nachweisbare Neutralfettpartikel kommen im M. tibialis anterior der Ratte vorwiegend in den mitochondrienreichen Fasern vom Typ C in der Nachbarschaft von Mitochondrien vor. Nach Glutaraldehyd-Osmium-Fixierung und Epon-Einbettung sind diese Partikel meist dielektronisch, seltener teilweise oder ganz adielektronisch. Auf 100 μm2 Schnittfläche durch C-Fasern findet man 3–4 Anschnitte von Fettpartikeln. Der mittlere Durchmesser der Anschnitte (d) ist 0,69 μm, der mit der graphischen Methode von Hennig bestimmte mittlere Durchmesser der Fettpartikel (d′) 0,80 μm. 2 h Narkose mit Pentobarbital beeinflussen weder Anzahl noch Durchmesser der Anschnitte. Nach 2 h Resorption von Maiskeimöl ist die Zahl der Anschnitte unverändert, der mittlere Durchmesser der Anschnitte bzw. der Partikel hat um etwa 20 % zugenommen (d=0,83 μm; d′=0,95 μm). Das entspricht einer Zunahme des morphologisch nachweisbaren Neutralfettes um 70 %. Da keine Pinocytose von Chylomikronen zu beobachten ist, wird angenommen, daß freie Fettsäuren durch das Plasmalemm in die Muskelfaser eindiffundieren und im Bereich vorhandener Fettpartikel als Triglyceride gespeichert werden.
    Notes: Summary In the anterior tibial muscle of rats triglyceride droplets predominantly appear within fibres rich in mitochondria (type C). In electron micrographs 3–4 of such droplets are present per 100 μm2 sectional area of C-fibres. The mean diameter of sections through fat droplets (d) is 0.69 μm, the mean diameter of the droplets (d′) as determined by Hennig's graphical method is 0.80 μm. Anaesthesia with pentobarbital (2 h) does affect neither number nor size of the particles. 2 h after application of corn oil into the stomach the number of fat droplets is unaltered, but the mean diameter has increased by 20 % (d=0.83 μm; d′=0.95 μm), corresponding to an increase of the volume of about 70 %. Pinocytosis of chylomicrones by muscle fibres has never been observed. Therefore it is supposed, that free fatty acids have passed the plasmalemma by diffusion and are incorporated into triglycerides and stored within pre-existing fat droplets.
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  • 100
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    Cell & tissue research 127 (1972), S. 439-461 
    ISSN: 1432-0878
    Keywords: Prechiasmatic gland (Organon vasculosum laminae terminalis) ; Rat ; Nerve endings ; Dense-cored vesicles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary On the basis of the present electron microscopic study of the rat median vascular prechiasmatic gland, the unmyelinated nerve fibers containing dense-cored vesicles may be classified in three categories. (1) Nerve endings containing isomorphic rounded dense-cored vesicles, 800–1600 Å in diameter with a predominance of vesicles between 1100 and 1300 Å. These vesicles are synthesized in the nerve cell perikarya which are localized principally in the lamina profunda of the outer subpial layer and also in the neuropil of the inner glial covering layer. One or more “cholinergic” axon terminals are in contact with the surface of these nerve cell perikarya. The dense-cored vesicles travel in the axonal process which branches into an extensive terminal network characterized by the presence of small varicosities. They abut on the pericapillary spaces but never against another neuron or effector cell. A few nerve processes course between the ependymal cells and terminate in the preoptic recess of the third ventricle. The dense-cored vesicles may contain one of the primary monoamines. (2) Nerve endings containing pleomorphic dense-cored vesicles, 500–1600 Å in diameter with a predominance of vesicles between 800 and 1100 Å. The latter granular vesicles are associated with small, clear-centered vesicles, 260–550 Å in diameter, which are often aggregated in the vicinity of thickenings of the plasma membrane and of cytoplasmic dense projections. The intercellular space and the cell plasma membrane, however, do not display any modification facing these structures. Synapse-like contacts are observed between these nerve endings and cells containing a great amount of microfilaments and glycogen particles in their cytoplasm. The latter cells possibly represent processes of ependymal cells. (3) Nerve endings containing a few large dense-cored vesicles in addition to a majority of synaptic vesicles.
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