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  • Articles  (21)
  • Electronmicroscopy  (21)
  • Springer  (21)
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  • 1980-1984
  • 1970-1974  (21)
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  • 1935-1939
  • 1972  (21)
  • Biology  (21)
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  • Articles  (21)
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  • Springer  (21)
  • American Geophysical Union (AGU)
  • Annual Reviews
  • Blackwell Publishing Ltd
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  • 1980-1984
  • 1970-1974  (21)
  • 1955-1959
  • 1935-1939
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 127 (1972), S. 9-33 
    ISSN: 1432-0878
    Keywords: Nervous system ; Speophyes (Coleoptera) ; Antennae ; Function ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Nos recherches au microscope électronique portent sur une structure nerveuse en lamelles découverte pour la première fois dans l'antenne duSpeophyes, qu'on étudie comparativement chez les Coléoptères hypogés et épigés. Nous constatons qu'elle existe à l'extrémité de l'antenne chez toutes les espèces cavernicoles de l'échantillon examiné ainsi que chez plusieurs espèces épigées. Nous n'avons pas rencontré cet organe à l'extrémité de l'antenne de trois espèces épigées; nous ne pouvons cependant pas affirmer qu'il n'existe pas, les articles inférieurs de l'antenne n'ayant pas été examinés. Son plus grand développement chez les espèces cavernicoles laisse supposer une fonction plus spécifiquement adaptée à ce milieu. La structure fine de ces lamelles présentant une étroite similitude avec celle des photorécepteurs, nous avons émis l'hypothèse d'une sensibilité à des rayonnements présents dans la grotte, par exemple au rayonnement infrarouge. Il faut souligner que la nature ciliaire de ces structures est en désaccord avec l'appartenance de l'Insecte à la lignée rhabdomérique.
    Notes: Summary The lamellated nervous system discovered in the antennae of the beetleSpeophyes, has been comparatively investigated in various hypogeous and epigeous species. It was found in almost all of the species studied in the tip of the antennae. It was, however, not detected in a few of the epigeous forms. Its extensive development in the cave develling species suggests a specific function in this particular environment. The fine structure of the lamellae is closely comparable to that of photosensory cells. Therefore it is assumed that they serve a similar function, i. e. the perception of infrared radiation in the caves. Its ciliary nature does not correspond to the rhabdomeric structure of insect eyes.
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  • 2
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    Springer
    Cell & tissue research 134 (1972), S. 351-366 
    ISSN: 1432-0878
    Keywords: Sensory cell ; Proboscis ; Glycera convoluta ; Papilla ; Electronmicroscopy ; Histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Chaque papille de la trompe chez Glycera convoluta contient un groupe central de deux à quatre cellules sensorielles primaires. Chaque cellule possède un noyau allongé situé à mi-hauteur de la papille. Le processus péripherique ou dendritique porte cinq à six cils qui traversent la cuticule et sont entourés chacun par un cercle de microvillosités; les cils se prolongent dans le cytoplasme par de fines racines ciliaires qui se réunissent pour former une seule énorme racine montrant une striation périodique. Le processus central ou axonal se prolonge dans le plexus nerveux sous-épithélial. Le rôle physiologique de ces cellules est discuté.
    Notes: Summary Each papilla in the proboscis of Glycera convoluta contains a central group of two to four primary sensory cells. Each one shows an elongated nucleus situated at half-height of the papilla. The peripheric or dendritic process bears five to six cilia traversing the cuticle; each of them is circled by a ring of microvilli. The cilia are prolonged in the cytoplasm by fine ciliary rootlets which gather themselves in a very big single root showing a periodic striation. The central or axonal process runs in the subepithelial nervous plexus. The physiological role of the cells is discussed.
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  • 3
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    Cell & tissue research 131 (1972), S. 399-416 
    ISSN: 1432-0878
    Keywords: Spermatozoon ; Pleurodeles ; Tail ; Morphogenesis ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résume La morphogenèse des éléments caudaux: filament de soutien, membrane ondulante, flagelle et filament marginal, est décrite durant les différents stades de la spermiogenèse. L'absence de cytochrome cytochimiquement décelable, prouve que l'acidophilie marquée du filament de soutien provient de protéines basiques cytoplasmiques ne dérivant pas des mitochondries. Leur origine nucléaire éventuelle est discutée. Le filament de soutien est homologué à la fibre dense externe no 3 du spermatozoïde des mammifères. Le filament marginal à structure périodique pourrait correspondre à la colonne dense longitudinale no 8 de la gaine fibreuse. A la fin de la spermiogenèse, le spermatozoïde présente une symétrie bilatérale. Une face ventrale et une face dorsale peuvent être définies par comparaison avec le spermatozoïde de mammifère.
    Notes: Summary The morphogenesis of the tail components: supporting filament, axial rod, undulating membrane, and marginal filament, are described through the differents spermiogenesis steps. The cytochemical cytochrome fate, demonstrated that the pronounced acidophilic properties of the supporting filament are related to the presence of the other cytoplasmic basic proteins. Their eventual nuclear origine is discussed. The supporting filament is homologous to the mammalian sperm outer dense fiber no 3. The marginal filament which shows a periodic structure, may correspond to the longitudinal column no 8 of the fibrous sheath. At the end of spermiogenesis, the spermatozoon shows a bilaterally symmetrical structure. A ventral face and a dorsal face may be defined by comparison with the insect and mammalian spermatozoon.
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  • 4
    ISSN: 1432-0878
    Keywords: Pancreas (frog) ; Intrinsic innervation ; Monoamines and AChE distribution ; Ligth, fluorescense ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The autonomic nervous system in the pancreas of Rana temporaria, R. ridi, bunda, R. esculenta and Hyla arborea was studied with histochemical methods of light: fluorescence, and electron microscopy. These species displayed the following common features: (1) a developed innervation whose topographic distribution was similar to that observed in the mammalian pancreas, (2) a richer nervous supply to the islets of Langerhans than to exocrine tissue, (3) a prevalence of cholinergic over adrenergic innervation in islets and exocrine parenchyma, (4) sporadic Cajal interstitial cell-like cells of a cholinergic nature, (5) in islets, the B-cells were mainly supplied by adrenergic, and the A2-cells by cholinergic nerve endings, (6) the occurrence of biogenic monoamines in B-cells and of acetylcholinesterase (AChE) in B- and A2-cells. These aspects together with observations on the fine structure, nature, and the intimate morpho-functional relationship of nerve terminals with blood vessels, acinar and endocrine cells, are discussed in connection with the findings of other authors.
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  • 5
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    Cell & tissue research 135 (1972), S. 361-382 
    ISSN: 1432-0878
    Keywords: Placenta (human) ; Syncytiotrophoblast ; Differentiation ; Function ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Entwicklung des Zottentrophoblasten der menschlichen Placenta von der 9. Woche bis zur Geburt wurde elektronenmikroskopisch untersucht. Dabei zeigt sich, daß die Differenzierung nicht kontinuierlich sondern in Schüben abläuft. Hiernach wurde eine Stadieneinteilung durchgeführt: Im undifferenzierten Tertiärzottenstadium (bis zur 14. Woche) ist das Zottensyncytium weitgehend einheitlich strukturiert. Nach dem unterschiedlichen Dilatationsgrad des rauhen endoplasmatischen Retikulums sowie Häufigkeit und Struktur apikaler Vakuolen ist eine noch weitergehende Unterteilung möglich. Durch zentrifugale Kapillarwanderungen bedingte Kernverschiebungen im Syncytium führen um die 15. Woche zur Ausbildung von Epithelplatten, Syncytialknoten, Proliferationsknoten und syncytialen Brücken. Hiermit wird der Übergang zum differenzierten Tertiärzottenstadium vollzogen. Um die 22. Woche treten Areale mit glattem endoplasmatischen Retikulum und Syncytiumlamellen über Langhanszellen hinzu. Eine weitere Untergliederung des kernlosen und des kernhaltigen Syncytiums führt ab der 28. Woche zum typischen Bild der reifen Placentazotte mit mosaikartig angeordneten, morphologisch und funktionell differenzierten Syncytiumarealen. Vergleiche mit biochemischen Aktivitätskurven der Placenta und mit tierischen Placenten bestätigen diese Stadieneinteilung und erlauben teilweise gleichzeitig eine funktionelle Deutung der Stadien und ihrer morphologischen Erscheinungsbilder.
    Notes: Summary The structural development of the human trophoblastic epithelium from the 9th week of gestation up to term has been investigated by means of electron microscopy. Up to the 14th week the syncytium of the tertiary villi shows an entirely homogenous ultrastructural pattern, although regional variants in both the amount of large apical vacuoles and the appearance of rough membranes exist. From approximately the 15th week on the capillaries grow eccentrically and approach very closely to the trophoblastic epithelium. The outbulging terminal vessels cause various differentiations of the overlying syncytium (syncytial knots or sprouts, syncytial bridges, epithelial plates). Accumulation of smooth membranes can be observed in the syncytial layer from the 22nd week onwards. The mature syncytium is characterized by subdivision of the formerly homogenous syncytial layer into morphologically and functionally different areas, which form a mosaic-like pattern due to irregular distribution of the nuclei and different ultrastructural organization of the cytoplasmic constituents. An attempt has been made to correlate the different stages of ultrastructural development with various biochemical and endocrinological data.
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  • 6
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    Cell & tissue research 125 (1972), S. 121-131 
    ISSN: 1432-0878
    Keywords: Hairless skin ; Mole ; Innervation of the dermis ; Simple encapsulated corpuscles ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Einfache eingekapselte Endigungen im Corium der unbehaarten Nasenhaut des Maulwurfs werden beschrieben. Diese Körperchen liegen im Nervenplexus unter den epidermalen Eimerschen Papillen. Sie sind oval, 30–40 µ lang und 15–20 µ dick und ihre Längsachse läuft parallel zur Oberfläche der Epidermis. Die Körperchen bestehen aus einer versorgenden Nervenfaser, einem Innenkolben, einem Subkapsularraum und einer Kapsel. Die Nervenfaser hat drei strukturell verschiedene Abschnitte: einen eintretenden myelinisierten Teil, einen im mittleren Abschnitt des Innenkolbens verlaufenden nicht myelinisierten Teil und eine terminale Verdickung, die fingerförmige Ausläufer zwischen die Lamellen des Innenkolbens streckt. Der Innenkolben besteht aus Lamellen, die von modifizierten Schwannschen Zellen gebildet werden. Die peripheren Lamellen sind dicker als die Lamellen, die das Axon umhüllen. Alle Lamellen zeigen eine starke pinozytotische Aktivität. Zwischen der äußersten Lamelle, die von einer Basalmembran umhüllt wird, und der Innenfläche der platten Kapselzellen liegt der Subkapsularraum. Er enthält Kollagenfasern und Fibroblasten. Die Kapsel wird von 1–2 Schichten sehr flacher Zellen gebildet, die die gleiche Struktur wie die Perineuralzellen der Nervenfaser besitzen. Der Unterschied zwischen dem Aufbau dieses Körperchens und dem Bau ähnlicher Endigungen im Corium anderer Säugetiere wird diskutiert.
    Notes: Summary In the corium of the hairless skin of the mole's nose simple encapsulated corpuscles are found and described. These corpuscles are embedded in the nerve plexus below the epidermal papillae of Eimer. They are oval, 30 to 40 µ in length and 15 to 20 µ in diameter, their longitudinal axis running parallel to the surface of the epidermis. The corpuscles consist of an afferent (dendritic) nerve fibre, an inner core, a subcapsular space and a capsule. The nerve fibre is composed of three sections: a myelinated portion, entering the corpuscle, a non-myelinated section running through the center of the inner core, and a terminal thickening sending finger-like branches between the lamellae of the inner core. The inner core consists of lamellae formed by modified Schwann's cells. The peripheral lamellae are thicker than those covering the axon. All lamellae show a great pinocytotic activity. The subcapsular space is located between the outermost lamella, covered by a basement membrane, and the inner surface of the flat cells belonging to the capsule. It contains collagen fibres and fibroblasts. The capsule is formed by 1 to 2 layers of very flat cells structurally resembling the perineural sheath cells of the nerve fibre. Differences in the arrangement of these corpuscles and that of similar endings in the corium of other mammals are discussed.
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  • 7
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    Cell & tissue research 125 (1972), S. 191-199 
    ISSN: 1432-0878
    Keywords: Smooth muscle cells ; Intercellular relationships ; Tunica muscularis externa ilei ; Small intestine ; Guinea pig ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Different intercellular relationships between smooth muscle cells are observed in the tunica muscularis externa of the ileum of guinea-pig. a) simple adjoining of the two muscle cells; b) nexus; c) desmosome-like attachment with dense aggregations on both membranes; d) projection from one muscle cell protruding into another muscle cell. All four types are found in the circular muscle layer. On the contrary, in the longitudinal layer clear-cut nexuses are not observed. Simple adjoining of muscle cells, nexuses, and desmosome-like attachments are observed between muscle cells of the circular layer and the longitudinallayer.
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  • 8
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    Cell & tissue research 123 (1972), S. 544-565 
    ISSN: 1432-0878
    Keywords: Glial cover of cortex (cat) ; Phases of development ; Whirled piles of membranes ; Astrocytic lamellae ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung An zahlreichen Altersstufen wird die Entwicklung der Gliadeckschicht des Cortex cerebri der Katze untersucht. Das neugeborene Kätzchen hat eine fast epitheliale Decklage, deren Zellen tanycytenartige Fortsätze (TF) in die Tiefe senden. Seine weitere Entwicklung läßt sich in 4 Phasen gliedern. 1. Auflockerungsphase (1.–15. Lebenstag): Die Perikarya der Deckzellen treten auseinander, so daß das Neuropil bis nahe an die Oberfläche vordringen kann. Aus den dunklen Zellen wird eine durchgehende oberflächliche Fortsatzlage (OF) gebildet. 2. Umbauphase (16.–30. Lebenstag): In ihr degenerieren die hellen Zellen, die ursprünglich etwa 50% der Oberfläche abdeckten. Aus den dunklen Zellen werden die ersten runden Fortsätze (RF) mit dichten Gliafilamenten und Glialamellen (LF) ohne Filamente gebildet. Am Ende der Phase sind zwischen allen OF Schlußleisten vorhanden. 3. Proliferationsphase (31.–45. Lebenstag): In dieser Zeit werden LF und RF in großen Mengen gebildet. Die ursprünglich cytoplasmareichen Gliazellen, die einen großen Golgiapparat besitzen, verwandeln sich in die cytoplasmaarmen Astrocyten der Deckschicht. 4. Reifephase (46.–60. Lebenstag): Zwischen allen Fortsatzarten wird eine große Zahl von Zellkontakten (specific junctions und Desmosomen) ausgebildet. Am Ende der Reifephase beginnt in Schicht I die Entwicklung der markhaltigen Nervenfasern. Die Bildung der LF, die aus den Membranwirbeln (MW) entstehen, wurde genauer untersucht. Die MW entwickeln sich im Perikaryon und sammeln anschließend in der Auflockerungsphase Material in Form von membranbegrenzten Granula. Während der Umbauphase werden sie in blasenartige Vorstülpungen des Perikaryon geschoben und bilden dort komplizierte Formen. Dabei müssen große Membranflächen enstehen, während zugleich die Granula verschwinden. Aus den verzweigten MW werden in der Proliferationsphase große Mengen von LF abgeschoben. Bei diesem Prozeß müssen intracelluläre Membranen in Plasmalemm verwandelt werden und intracelluläre Cisternen Anschluß an den extracellulären Raum gewinnen. Die Bedeutung dieses Vorganges wird diskutiert.
    Notes: Summary The development of the glial cover of the cat's cortex cerebri examined on many stages of age after birth comprises four phases. The newborn kitten possesses a nearly epithelial cover of cortex. Each of the covering cells extends a process (TF) into the depth similar to that of a tanycyte. 1. Phase of loosening (first to 15th day of life): The perikarya of the covering cells disperse in such a way that the neuropil is pushing up nearly as far as to the border of the surface. The dark cells are forming a closed layer of flat superficial processes (OF). 2. Phase of transformation (16th to 30th day of life): Cells having a light contrast degenerate. They originally covered about 50% of the surface. The dark cells develop the round or oval processes (RF) with closely packed filaments of glia and the astrocytic lamellae (LF) without filaments. The terminal bars are built up at the end of this phase between all OF. 3. Phase of proliferation (31st to 45th day of life): Very many LF and RF are developed. The glia cells which originally have had a big cytoplasm with a large Golgi complex are transformed into astrocytes of the cover with a small border of cytoplasm. 4. Phase of maturation (46th to 60th day of life): The areas of cell attachment (specific junctions and desmosomes) are formed in large quantities between all kinds of processes. The myelinisation in layer I is beginning after the phase of maturation. The special development of the LF is determined. They are formed from concentric whirled piles of membranes (MW). The MW arise in the perikaryon and are gathering material in granules which are membrane bounded during the phase of loosening. The MW are shifted into bubblelike bulges of the perikaryon during the phase of transformation and afterwards form very complicated figures. At the same time very many planes of membranes must be developed in the MW while the granules disappear. Then the ramified MW deliver a great amount of LF. The intracellular membranes must be transformed into the plasmalemma during this delivery and the intracellular cisternae are opened towards the extracellular space. The significance of this process is discussed.
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  • 9
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    Cell & tissue research 128 (1972), S. 406-425 
    ISSN: 1432-0878
    Keywords: Parafollicular Cells ; Rat ; Normalcalcemia ; Vitamin D2 ; Electronmicroscopy ; Histochemical fluorescence method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    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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  • 10
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    Cell & tissue research 133 (1972), S. 1-12 
    ISSN: 1432-0878
    Keywords: Golgi complex ; Ovary ; Bat ; Cytodifferentiation ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Dense lamellar bodies (DLB) were noted in immature cells in the developing ovary of the free-tailed bat. The DLB appear to be formed in the nucleus. They pass through the nuclear membrane into the cytoplasm. There they give rise to parallel stacks of flattened cisternae which are representative of typical dictyosomes. During the first meiotic prophase the dictyosomes aggregate to form the Golgi complex.
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  • 11
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    Cell & tissue research 133 (1972), S. 519-527 
    ISSN: 1432-0878
    Keywords: Myofibroblasts ; Testis (human) ; Connective tissue ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung In der Lamina propria menschlicher Hodenkanälchen wurden spezialisierte Fibroblasten beobachtet. Die Zellen sind durch Bündel parallel geordneter Plasmafilamente gekennzeichnet, deren Durchmesser rund 80 Å beträgt. Die Filamentbündel verlaufen parallel zur Oberfläche der lamellär ausgebreiteten Zellen und inserieren in elektronendichtem, granulärem Material, das der Innenseite der Zellmembran anliegt. Es wird angenommen, daß dieses Fibrillensystem kontraktil ist; die dichtere oder lockerere Vernetzung der Filamente innerhalb der Bündel würde dem kontrahierten oder erschlafften Zustand der Zellen entsprechen. Die beschriebenen spezialisierten Fibroblasten sollten der Gruppe der Myofibroblasten zugeordnet werden (Gabbiani, Ryan und Majno, 1971).
    Notes: Summary A special type of fibroblast is observed in the connective tissue of seminiferous tubules in human testes. These cells are characterized by a fibrillar system consisting of parallel arranged cytoplasmic filaments. The filaments have a mean diameter of 80 Å. Bundles of filaments run parallel to the surface of the flattened cells. The filaments insert in a dense, granular material which is connected with the cell membrane. This fibrillar system is thought to be contractile; the dense or more loose texture of the filaments within the bundles may correspond to the contracted or relaxed state of the cell. The specialized fibroblasts described are supposed to belong to the group of myofibroblasts (Gabbiani, Ryan and Majno, 1971).
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  • 12
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    Cell & tissue research 123 (1972), S. 496-507 
    ISSN: 1432-0878
    Keywords: Rat incisor ; Tooth eruption ; Ectopic enamel organ ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Durch regelmäßig wiederholtes mechanisches Kürzen des rechten unteren Rattenschneidezahnes wurde eine beschleunigte Eruption hervorgerufen. Nach 15–17 Tagen trat eine Störung der Schmelzentwicklung in Form einer Produktion von kreideweißem statt normal pigmentiertem Schmelz und ein rotbräunliches Häutchen im Bereich des gingivalen Epithelverschlusses in Erscheinung. Dieses Häutchen wurde nach intravitaler Fixierung mit Glutaraldehyd abpräpariert und licht- und elektronenmikroskopisch untersucht. Das Häutchen besteht aus mehreren übereinander gelagerten Zellschichten: aus Ameloblasten, einem typischen Papillarorgan, einer Bindegewebsschicht und aus flachen Deckzellen. Die Ameloblasten im Bereich des Epithelverschlusses befinden sich im Stadium der frühen, die Ameloblasten des aus dem Epithelverschluß hervorwachsenden Häutchens dagegen im Stadium der späten Maturation. Die Ultrastruktur des gesamten Papillarorgans läßt auf eine intensive metabolische Funktion und auf Ionentransport schließen. Pigmentgranula, die bei normaler Eruption im Maturationsstadium sowohl im Papillarorgan als auch in den Ameloblasten vorkommen, wurden nur im Bereiche des Epithelverschlusses in vaskulären Elementen und in perivaskulären Bindegewebszellen gefunden. Die Oberfläche des Häutchens wird von einer schmalen Schicht flacher, organellenarmer Zellen gebildet. Das bei beschleunigter Eruption aus dem Epithelansatz hervorwachsende Häutchen ist ein ektopisches Schmelzorgan, dessen rotbräunliche Färbung von der reichen Gefäßversorgung herrührt.
    Notes: Summary An accelerated eruption of the right mandibular rat incisor was induced by its repeated, mechanical shortening. Fifteen to seventeen days after beginning of the experiment a disturbance of enamel development occured, manifested by production of white, opaque enamel instead of normally pigmented enamel and by appearance of a redbrownish membrane overlying the enamel. This membrane was intravitally fixed with glutaraldehyde and after dissection processed for histologic and electronmicroscopic investigation. The membrane consists of ameloblasts, a typical papillary organ, a connective tissue layer and of flat surface cells. The ameloblasts near the epithelial attachment are in early maturation state, the ameloblasts of the outgrowing membrane show signs of reduction, typical for late maturation. The papillary organ of the entire membrane showes ultrastructural equivalents of high metabolic activity as well as of fluid transports. Pigment granules, which in normal eruption occur in the maturation state in the papillary cells and in ameloblasts, are absent in these cells of the membrane. They were only seen in perivascular elements and in connective tissue cells near the epithelial attachment. On the oral surface the membrane is covered by a thin layer of flat, degenerated cells poor in organelles. These findings support the concept, that the membrane growing out of the epithelial attachment in accelerated eruption of the rat incisor, is an ectopic enamel organ. The red-brownish colour is not due to pigment accumulation but to its rich vascularization.
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  • 13
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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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  • 14
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    Cell & tissue research 128 (1972), S. 19-30 
    ISSN: 1432-0878
    Keywords: Microbodies ; Hepatic cell ; Influence of Allylisopropylacetamide ; Catalase ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Multiple intraperitoneal injections of AIA in rats cause a decrease in matrix material and loss of endogenous peroxidatic activity in hepatic cell microbodies. These changes are detectable as early as 48 hours after commencing injections and are prominent by 5 days. On cessation of injections, recovery of normal microbody morphology is rapid but peroxidatic activity of microbodies returns more slowly. There is no evidence of increased destruction of microbodies during the recovery period. These observations support the concept that microbody constituents may be able to exchange independently of turnover of the entire organelle.
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  • 15
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    Cell & tissue research 128 (1972), S. 83-99 
    ISSN: 1432-0878
    Keywords: Capillaries ; Cerebellar cortex ; Cat ; Blood-brain-barrier ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Kapillaren im Kleinhirn der Katze haben einen Durchmesser von 3,5–12 μ. Im Stratum granulosum finden sich vorwiegend engere, im Stratum moleculare und in der Purkinjezellschicht meist weitere Kapillaren. Die Endothelzellen bilden schmale Lamellen, die sich teilweise überlappen und durch „tight junctions“ miteinander verbunden sind. Vom umgebenden Kleinhirngewebe sind sie durch eine Basalmembran abgegrenzt, die sich häufig in zwei Schichten spaltet, zwischen denen Perizyten mit ihren Fortsätzen liegen. Diese sind vornehmlich im Stratum granulosum am Aufbau der Kapillarwand beteiligt. Um die Kapillaren bilden Astrozyten mit ihren Fortsätzen, zum großen Teil aber auch mit ihren Perikaryen, einen unvollständigen Mantel. An den von Astrozyten freien Anteilen der Kapillaroberfläche grenzen Oligodendrozyten, Körnerzellen und Golgizellen mit ihren Perikaryen direkt an die Basalmembran der Kapillaren. Purkinjezellen liegen dagegen nicht unmittelbar der Kapillare an, sondern sind immer durch eine Schicht von Korbzellaxonen und Gliafortsätzen von der Basalmembran getrennt. Kapillaren mit einem Durchmesser von mehr als 10 μ besitzen einen perikapillären Raum. Dieser ist sowohl gegen die Glia als auch gegen das Endothel der Kapillare durch eine Basalmembran abgegrenzt. Im perivaskulären Raum findet man Perizyten, Fibroblasten und zirkulär verlaufende kollagene Fasern.
    Notes: Summary The capillaries in the cerebellar cortex of the cat have a diameter varying from 3.5 to 12 μ. In the granular layer the capillaries have a smaller diameter than those in the molecular and the Purkinje-cell layer. The endothelium forms slender lamellae which partially overlap. These lamellae are connected with each other by tight junctions. The capillaries are separated from the pericapillary compartment by a basement membrane which often splits into two layers; in between these layers processes of pericytes are located. The pericytes make up a part of the capillary wall mainly in the granular layer. Around the capillaries the astrocytes form an incomplete glial sheath with their processes and also with their pericaryon. Those parts of the capillary basement membrane which are not covered by astrocytes or their processes, are in contact with oligodendrocytes, granule cells or Golgi cells. The Purkinje cells have no intimate contact to the capillary, they are always separated from the basement membrane by a thin layer of basket cell axons and processes of astrocytes. The capillaries with a diameter greater than 10 μ often have a perivascular space. This space is separated from the endothelium as well as from the nervous tissue by a basement membrane. In the pericapillary space pericytes, fibroblasts and circularly arranged collagenous fibers are located.
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  • 16
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    Cell & tissue research 131 (1972), S. 223-233 
    ISSN: 1432-0878
    Keywords: Milk (rat) ; Fat globule ; Apocrine secretion ; Electronmicroscopy ; Enzyme analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary LDH and MDH activities were found to increase after freeze-thawing of the cream and a non-fat fraction of rat milk isolated by centrifugation. Electronmicroscopy of these fractions revealed that cellular components occurred especially in association with milk fat globules but also in combination with secretion granules. The fat globule fraction represented only 20% of the milk volume but accounted for more than 50% of the LDH and 75% of the MDH activities in milk. The results show that in the rat mammary gland an apocrine secretion type occurs. The reason why the LDH and MDH activities increase in the milk during the lactation of the rat must be that increasing amounts of cellular material is passed into milk at secretion, containing increasing activities of LDH and MDH.
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  • 17
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    Cell & tissue research 133 (1972), S. 21-33 
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Transplants ; Cell contacts ; Neuroeffector bundles ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Segments of the taenia coli from guinea-pig were transplanted into the anterior chamber of the eye. Depending on such factors as the total volume of the transplant and the presence or absence of ganglion cells degeneration was either very extensive (90% or more of the total number of muscle cells) or localized (alternating regions of degenerating and normal structure). During days 1–2 muscle cells lost their plasma membranes so that their cytoplasmic contents were dispersed into the intercellular spaces. Many cells produced numerous small processes which were pinched off and dispersed in a similar manner. Following a period of intense mitotic activity (3–8 days) numerous cells with the characteristics of embryonic smooth muscle cells were evident. Within 10–14 days these differentiating cells produced bulbous protrusions and assumed more irregular outlines than at 3–8 days. The protrusions formed close contacts (50–100Å intercellular space) and tight junctions between adjacent muscle cells. Aggregation of muscle cells into bundles was under way between 14–28 days. At approximately 4–6 weeks these developing muscle groups were invaded by nerve fiber bundles. The pattern of the innervation and the form and size of the muscle bundles simulated the normal. These findings are discussed in relation to the possible functions of the intercellular contacts and cellular protrusions which characterise various periods of regeneration.
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  • 18
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    Cell & tissue research 132 (1972), S. 231-244 
    ISSN: 1432-0878
    Keywords: Eye ; Pecten oculi ; Capillaries ; Enzyme histochemistry ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Im Endothel der Kapillaren des Pecten der Augen von Haustaube und Lachmöwe (Larus ridibundus) lassen sich lichtmikroskopisch alkalische und saure Phosphatase sowie Aminopeptidase nachweisen. Bernsteinsäuredehydrogenase und verschiedene Esterasen fehlen dagegen. Im Elektronenmikroskop ist das Kapillarendothel des Pecten der Lachmöwe durch dichte apikale und basale Mikrovillisäume, Mitochondrienansammlungen, zahlreiche polymorphe elektronendichte Granula, in reichem Maße vorhandene Ribosomen und multivesikuläre Körper gekennzeichnet. Zwischen Basallamina und Endothelzelle befindet sich ein weiter mit Fibrillen gefüllter Raum. Die Pigmentzellen des Pecten bilden mitochondrienhaltige Füßchen aus, die sich der Basallamina der Kapillaren anlegen. Die Oberfläche des Pecten wird von einer weiteren Basallamina gebildet; auch ihr lagern sich Füßchen der Pigmentzellen an. Die vorliegenden histochemischen und feinstrukturellen Befunde und Angaben aus der Literatur lassen vermuten, daß das Kapillarendothel im Pecten besondere Anpassungen an verstärkt ablaufende Transportvorgänge aufweist.
    Notes: Summary The endothelium of the capillaries in the pecten of the eyes of domestic pigeons and blackheaded gulls (Larus ridibundus) gives a positive reaction for alkaline and acid phosphatase, as well as for aminopeptidase. Negative results have been obtained for succinic-acid dehydrogenase and various esterases. In the electron microscope the capillary endothelium in the pecten of the blackheaded gull is characterized by densely packed apical and basal microvilli, accumulations of mitochondria and polymorphic electron-dense granules, numerous ribosomes and relatively common occurrence of multivesicular bodies. The endothelial cells are separated from their basal lamina by wide spaces which are filled by fibrils. The pigment cells of the pecten extend mitochondria-containing processes towards the basal lamina of the capillaries. The surface of the pecten is bound by a further basal lamina, which is underlain by other projections of the pigment cells. The present histochemical and fine-structural findings and evidence derived from the literature suggest that the capillary endothelium of the pecten shows particular adaptations in respect of transport mechanisms.
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  • 19
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    Cell & tissue research 132 (1972), S. 297-322 
    ISSN: 1432-0878
    Keywords: Neonatal brain (rabbit) ; Ependymal cells ; Subependymal cells ; Lateral ventricle ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural characteristics of a concentration of mitotically active cells near the lateral margin of the lateral ventricle was studied in the neonatal rabbit brain. This area, termed the caudato-pallial area, consists of subependymal cells, neuroblasts, microglial cells and astroblasts bordering a layer of ependymal epithelial cells. The character of the ependymal cells in this area indicates a persistence of embryonic conditions favoring the development of neuroblasts and astroblasts. It is not known what type of cells are produced in the subependymal layer since the primitive subependymal cells have no features which would clearly relate them to nerve or glial cells. Of the 80 subependymal cells which were reconstructed from serial sections none have processes extending beyond the limits of the subependymal layer. They range in form from simple cells devoid of processes to complex cells with several short cellular extensions. The presence of intermediate forms with transitional cytologic features indicates simple and complex cells may represent different stages in the mitotic cycle of a single cell type. No direct evidence was obtained to support the concept that the small ramified microglial cells of the caudato-pallial area or round and amoeboid microglial cells near the corpus callosum arise through mitosis of nearby ependymal or subependymal cells.
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  • 20
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    Cell & tissue research 134 (1972), S. 167-173 
    ISSN: 1432-0878
    Keywords: Fenestrated capillaries ; Transplantation ; Vas deferens ; Ureter ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This paper discusses the possibility that fenestrated capillaries may be induced by the presence or action of epithelial cells. Fenestrations were shown to exist in a number of capillaries in close proximity to the epithelium in the in situ guinea-pig vas deferens and ureter. These results suggest further roles for the vas deferens and ureter than those previously conceived. Transplants of these tissues in the anterior eye chamber were, by two weeks, highly vascularized. Those transplants containing epithelium showed fenestrated capillaries in close proximity to these cells. However, in transplants which did not contain epithelial cells, no fenestrations were noted in capillaries.
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  • 21
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    Cell & tissue research 135 (1972), S. 563-568 
    ISSN: 1432-0878
    Keywords: Pore cells ; Freshwater snails ; Haemoglobin ; Haemocyanin ; Cytochemistry ; Electronmicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary One of the cell types occurring in the connective tissue of gastropods and bivalves is thepore cell. Cells of this type have a characteristic morphology in that their plasmamembrane has many invaginations bridged by cytoplasmic tongues. In the well developed granular endoplasmic reticulum and in these invaginations fine granular material, sometimes arranged in crystalline patterns, is present. InLymnaea stagnalis this material has been identified as haemocyanin on a morphological basis. Histochemical and ultrastructural results on pore cells of 2 snail species(Biomphalaria glabrata, Planorbarius corneus) having haemoglobin in their blood indicate that the pore cells in these species synthesize haemoglobin. Possible other functions of pore cells are briefly discussed.
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