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  • Articles  (17)
  • Scanning electron microscopy  (10)
  • Neurohypophysis  (7)
  • Springer  (17)
  • 2020-2020
  • 1970-1974  (17)
  • 1945-1949
  • 1973  (17)
  • Biology  (17)
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  • Articles  (17)
Publisher
  • Springer  (17)
Years
  • 2020-2020
  • 1970-1974  (17)
  • 1945-1949
Year
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  • 1
    ISSN: 1432-0878
    Keywords: Fourth ventricle ; Human ; Ependyma ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scanning electron microscopy was used to assess the ultrastructural differences exhibited by the varigated ependymal lining of the near-term human fetal 4th ventricle. The central portion of the fourth ventricular floor, including the median sulcus is punctuated by numerous clumps of cilia. The density of cilia here is not as great as that described for other regions of the human cerebral ventricular system; accordingly, underlying substructure can be noted. There are distinct differences between ependymas that line the floor of the fourth ventricle with those of the adjacent area postrema. The latter region possesses not cilia, but instead exhibits a dense knap of microvilli. The ultra-architecture of the choroid plexus is relatively similar to that of other circumventricular organs with the exception that it possesses small isolated groups of cilia as well as microvilli. These findings are discussed with respect to the dynamics of local CSF movement and flow, ependymoabsorption and ependymosecretion
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  • 2
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Neurohypophysis ; Exocytosis ; Freeze-etching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The freeze-etching technique was used in studies of cell surface phenomena during the release of secretory products from the adenohypophysis and from neurosecretory terminals of rats in which exocytosis had been stimulated by the administration of hypothalamic extracts (somatotrophs, thyrotrophs, gonadotrophs and mammotrophs) or severe hemorrhage (neurohypophysis). The observations suggest that secretory granules are extruded through an opening at the tip of a protrusion of the cellular surface. The protrusions seem to result from the abutting of secretory granules on the inner surface of the plasma membrane. These structural details revealed in freeze-etched preparations have not been seen previously in conventional micrographs of ultrathin sections and may provide a clue to the mechanism of secretion.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 136 (1973), S. 461-477 
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Acipenseridae ; Neurosecretion ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neurohypophysis of sexually mature male and female Acipenser güldenstädti Brandt and Acipenser stellatus Pallas was studied light and electron microscopically. The recessus hypophysei lined with ependymal cells of two main types, “narrow” and “wide”, are in the center of the neurohypophysial “roots”. Processes from both cell types run radially to the basement membrane of the connective tissue layers abutting on the hypophysial intermediate lobe. Protrusions penetrating deep into the recessus hypophyseus are found in the apical parts of the “wide” cells. Pituicytes are rare in the neurohypophysis. The ultrastructure of both ependymal cell types and of the pituicytes is described. Nonmyelinated “Gomori-positive” (peptidergic) neurosecretory A1 and A2 type fibres and their terminals containing elementary neurosecretory granules (1400–1800 Å and 1000–1400 Å respectively) are the main structural elements of the neurohypophysis. Some “dark” and single myelinated neurosecretory fibres have been found. The adrenergic fibres (type B) were described earlier (Polenov et al., 1972a). The structural peculiarities of the neurohypophysis are discussed in functional and comparative-morphological terms.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 138 (1973), S. 31-39 
    ISSN: 1432-0878
    Keywords: Olfaction ; Fishes ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The olfactory rosettes of Tarletonbeania crenularis are contained within paired membranous olfactory chambers opening to the exterior through a pair of nostrils. The margins of the anterior nostril form an infundibulum that may direct a current of water between the lamellae of the olfactory rosette and out of the posterior nostril as the fish swims through the water. The number of lamellae in a rosette is variable, and each consists of an olfactory epithelium containing receptor cells, supporting cells, basal cells, mucus cells and bipolar neurons. The olfactory surface for the most part is nonciliated and appears rugose in scanning electron micrographs. Receptor elements are located along the central axis of the rosette and on the surfaces of the distal margins of the lamellae.
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  • 5
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    Electronic Resource
    Springer
    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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  • 6
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Membranes ; Exocytosis ; Ultrastructure ; Freeze-fracturing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Posterior pituitary glands from normal rats, and rats which had been deprived of water for varying periods, were examined by the freeze-fracture method. This technique reveals large areas of the nerve cell membrane. Images consistent with exocytosis as the mechanism of release of the neurohypophysial hormones were observed. These modifications were most numerous after the rat had been starved of water for 2 days. In normal rats, the large number of neurosecretory granules within the nerve fibres caused a bulging of the nerve cell membrane. The “bulges” disappeared 2 days after removal of drinking water. Regions of the membrane displaying “bulges” were characterised by the absence of the typical membrane-associated particles. It is postulated that the close proximity of the neurosecretory granules to the nerve cell membrane may result in rapid fusion of the neurosecretory granules on stimulation of the gland. The change in properties of the nerve cell membrane overlying the neurosecretory granules, as suggested by the loss of membrane-associated particles, may represent a change in the structure of the membrane to a form which is more favourable for fusion.
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  • 7
    ISSN: 1432-0878
    Keywords: Retinal pigment cells ; Retinal cell differentiation ; Retinal receptor cells ; Chicken ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The surface of the retinal pigment epithelium in chick embryos and young chicks was studied by scanning electron microscopy. It is demonstrated, that pigment cells not only have fine processes on their retinal surface, but also to a considerable extent on their basal cell membrane. The occurrence of these processes was studied during differentiation of the retina. The appearance of these surface differentiations can no longer be interpreted solely as the result of membrane infoldings but to be mainly the result of membrane sprouting processes. The formation of processes on the retinal surface of pigment cells precedes that of the processes on the choroidal surface. The length of the mature processes on the apical surface is greater than the length of those on the basal surface. The appearance of the fine cell processes is correlated with the functions of pigment epithelium and with the differentiation of retinal receptor cells. This study illustrates that the technique of scanning electron microscopy is not limited to the examination of naturally occurring tissue surfaces, but can be extended to the investigation of tissue fractures.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 138 (1973), S. 585-589 
    ISSN: 1432-0878
    Keywords: Salmo gairdneri (Teleostei) ; Pineal organ ; Photoreceptor cells ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Im rasterelektronenmikroskopischen Bild des Pinealorgans vonSalmo gairdneri kann man drei verschiedene Außengliedtypen der Photorezeptoren unterscheiden. Diese Ergebnisse werden im Hinblick auf die Ultrastrukturkonzepte von Rüdeberg (1969) und Bergmann (1971) diskutiert. Rasterelektronenmikroskopische Studien erleichtern die anatomische Klassifizierung von pinealen Sinneszellen aufgrund ihrer Außengliedform.
    Notes: Summary The outer segments of pineal photoreceptor cells ofSalmo gairdneri were investigated with the scanning electron microscope. The scanning electron micrographs showed three different types of outer segments. These results are discussed with respect to the ultrastructural concepts of Rüdeberg (1969) and Bergmann (1971). Scanning electron microscopy permits better anatomical classification of pineal photoreceptor cells according to the form of their outer segments.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 136 (1973), S. 307-328 
    ISSN: 1432-0878
    Keywords: Ductus cochlearis ; Lizard ; Sensory hair cells ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The sensory hair cells of the ventral 2/3 of the papilla basilaris of Gekko gecko are divided into anterior (pre-axial) and posterior (post-axial) portions by a mid-axial gap or hiatus where there are no hair cells. There is no separation of the hair cells in the dorsal third of the papilla. There are three tectorial membrane modifications: an attached thickened membrane covering the pre-axial hair cells, sallets covering the post-axial hair cells, and an attached filamentous membrane covering the dorsal hair cells. The number of hair cells is greatest ventrally and decreases dorsally. There are approximately 2000 to 2100 hair cells. The kinocilia of the hair cells of the anterior halves of both the pre- and the post-axial vertical hair-cell rows are oriented posteriorly, while the kinocilia of the posterior halves are oriented anteriorly. The kinocilia of the hair cells of the dorsal third of the papilla are mostly oriented posteriorly. Thus, kinocilial orientation of the ventral 2/3 of the papilla is doubly bidirectional, and the dorsal 1/3, largely unidirectional.
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  • 10
    ISSN: 1432-0878
    Keywords: Olfactory mucosa ; Olfactory receptors ; Fish ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Durch rastermikroskopische Untersuchungen lassen sich mehrere, morphologisch unterschiedliche Rezeptoren in der Regio olfactoria des Goldfisches (Carassius auratus) unterscheiden. Dabei muß vorläufig offen bleiben, ob den morphologischen Varianten entsprechende funktionelle Unterschiede zuzuordnen sind. Auf den Lamellen der Riechrosette sind Sinneszellareale und in ihnen Flimmerzellgruppierungen zu beobachten. Die wechselnde Dichte der verschiedenen Rezeptoren in einzelnen Sinneszellarealen wird betont. Die Befunde werden zu Riechtheorien und zu der Frage in Beziehung gesetzt, ob es eine räumliche Zuordnung von Zonen des Riechepithels zu bestimmten Anteilen des Bulbus olfactorius gibt.
    Notes: Summary Investigations by scanning electron microscopy demonstrate the existence of several morphologically different types of olfactory receptors in Carassius auratus. The structural differences, however, do not allow a definite classification of sensory cells into functionally different elements. The olfactory organ has a central axis with lamellae emerging at both sides of it. On these lamellae sensory areas with densely packed receptor cells and with groups of ciliated cells exist. The terminals of the receptor cells show a great polymorphism of their surface. The morphologically different receptor cells are not equally distributed over the olfactory organ but differ from each other in quantity and density. The morphological results are discussed in relation to olfactory theories and in relation to the question whether there are topographical projections between the peripheral olfactory organ and the Bulbus olfactorius.
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  • 11
    ISSN: 1432-0878
    Keywords: Neurosecretion ; Neurohypophysis ; Neurophysin ; Diabetes insipidus ; Vasopressin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The subcellular distribution of radioactive neurophysin and the release of neurophysin from isolated neurosecretory granules (NSG) from the posterior pituitary gland were studied at various time intervals after injection of (35S) cysteine into the supraoptic nucleus under various functional conditions. In consistency with previous findings (Norström, 1972), increased amounts of radioactive neurophysin were recovered extra-granularly at longer time intervals after isotope injection. Increased quantities of “free” labelled neurophysin were found in lactating rats and homozygous diabetes insipidus (DI) rats 7 and 1 day after injection, respectively. Salt-loading for 4 days did not affect the subcellular distribution of radioactive neurophysin 1 day after injection of (35S) cysteine. 8.5 days after isotope injection acute haemorrhage was followed by augmented amounts of radioactive neurophysin among the soluble proteins, but at 1 day no difference was observed between bled animals and controls. The “spontaneous” release of neurophysin form NSG was higher in stimulated animals and increased with time after isotope injection in controls as well as in experimental animals. The absolute increase in release of neurophysin in response to ATP was higher in stimulated rats whereas NSG from DI rats did respond poorly to ATP.
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  • 12
    Electronic Resource
    Electronic Resource
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    Cell & tissue research 142 (1973), S. 515-524 
    ISSN: 1432-0878
    Keywords: Arteriovenous anastomoses ; Carotid body ; Cat ; Corrosion casting technique ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung In den arteriennahen, peripheren Bereichen des Glomus caroticum der Katze wurden arteriovenöse Verbindungen nachgewiesen, die ihrem Charakter nach unterschiedlich sind. Es ist allerdings noch nicht zu entscheiden, ob derartige Anastomosen regelmäßig vorkommen und wie sie funktionieren. Die beschriebenen Gefäßverbindungen konnten lichtmikroskopisch anhand von histologischen Serienschnitten und mit Hilfe einer weiterentwickelten Korrosionstechnik im Rasterelektronenmikroskop dargestellt werden.
    Notes: Summary In artery surrounding areas in the periphery of the carotid body of the cat we found arteriovenous anastomoses differing in respect to their character. So far, it is not yet to decide the frequency of their occurrence and their functional significance. The anastomoses were demonstrated by light microscopy of serial sections and by scanning electron microscopy with a more developed corrosion casting technique.
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  • 13
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    Cell & tissue research 136 (1973), S. 169-176 
    ISSN: 1432-0878
    Keywords: Cerebral ventricles ; Ependyma ; Sheep ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scanning electron microscopy of the third ventricle of sheep demonstrates areas of ciliated ependymal cells at the dorsal and middle third. The cilia of the dorsal portion of the ventricle have biconcave discs that are attached to each cilium by a slender stalk. The lower third and floor of the ventricular wall, as well as the pineal recess, are largely covered by ependymal cells that possess numerous microvilli with only a few isolated cilia scattered along cell surfaces. The infundibular recess is papillated with apical blebs of the ependymal cells that project into the lumen of the recess. Measurements of these surface elements indicate an average diameter of 0.28 μ for cilia, 0.10 μ for microvilli and 0.50 μ for the apical blebs of the infundibular recess. The functional significance of the regional differences in surface structures is discussed in relation to cerebrospinal fluid movement, ependymoabsorption and ependymosecretion.
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  • 14
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    Cell & tissue research 137 (1973), S. 361-374 
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Rat ; Saline-treatment ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neural lobes from rats which had been allowed to drink hypertonic saline for five days were examined electron microscopically and by bioassay of oxytocin levels. The profound changes in the ultrastructure were examined and the reversal of these changes in morphology was followed until the hormone levels returned to normal. The recovery of the gland as measured by the two parameters of structure and hormone content indicated that the morphological recovery apparently preceded the hormone level recovery, a factor which might be explained by continued release of hormone during the period of recovery.
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  • 15
    ISSN: 1432-0878
    Keywords: Adenohypophysial cells ; Neurohypophysis ; Lebistes reticulatus ; Osmoregulatory mechanism ; Light microscopy, Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pituitary of the larval guppy, Lebistes reticulatus (Peters), was investigated cytologically in relation to the osmotic properties of the environment. In larvae of Stage I, removed from the mother about one week before birth, the sizes of the nuclei of the prolactin, STH, ACTH, and pars intermedia cells were small. The nuclei of these cell types became larger when Stage I larvae were transferred into fresh water (F. W.); however, these animals did not survice. In Stage-II larvae, removed from the mother just before birth, the nuclei of the abovementioned adenohypophysial cells were larger than those of the Stage-I larvae. Stage-II larvae were able to survive in F. W. Thus, it seem that osmoregulatory mechanisms in the larval guppy develop between Stages I and II. The nuclei of prolactin, STH, ACTH and pars intermedia cells decreased significantly in size after birth (0-hr). When larvae of the 0-hr group were immersed in 1/3 sea water (S. W.), only the nuclei of the ACTH cells increased in size. The neurohypophysis of Stage-I larvae contained a very small amount of aldehyde-fuchsin (AF)-positive material, while the neurohypophysis of Stage-II and 0-hr fish was rich in this material. When Stage-I larvae were immersed in F. W., the neurohypophysis showed as great an accumulation of AF-positive material as Stage-II and 0-hr fish.
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  • 16
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    Cell & tissue research 141 (1973), S. 235-253 
    ISSN: 1432-0878
    Keywords: Teleost yolk sac ; Pericardial sac ; Chloride cell ; Osmoregulation ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Le microscope électronique à balayage montre l'existence d'un réseau complexe de microcrêtes à la surface de la vésicule vitelline et du sac péricardique de l'embryon de Poecilia reticulata. Cette étude permet également de préciser la localisation, l'aspect et la répartition des «cellules à chlorure» et de proposer un schéma tridimensionel de l'organisation infrastructurale de la paroi de la vésicule vitelline. Un choc osmotique détermine rapidement un mouvement d'étalement des cellules épithéliales sur la surface apicale libre des «cellules à chlorure». La signification de ces résultats est discutée en rapport avec le problème de l'osmorégulation embryonnaire chez les Poissons, en particulier chez les Cyprinodontes vivipares de la famille des Poeciliidae.
    Notes: Summary A complex network of microridges is revealed by scanning electron microscopical examination of the yolk sac and embryonic pericardial sac surface of Poecilia reticulata. This study also specifies the localization, aspect and distribution of “the chloride cells”. A tridimensional diagram of the ultrastructural organization of the yolk sac wall is suggested. Osmotic stress quickly induces an overlapping of adjacent epithelial cells on the free apical surface of the “chloride cells”. These findings are discussed in relation to the problem of embryonic osmoregulation in fishes and especially in viviparous Poeciliids.
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  • 17
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    Cell & tissue research 143 (1973), S. 451-463 
    ISSN: 1432-0878
    Keywords: Retina ; Pigment epithelium ; Photoreceptors ; Rana catesbiana ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The retina and pigment epithelium of the bullfrog (Rana catesbiana) were studied with the scanning electron microscope. Fixed-dehydrated tissues were critical point dried with CO2, then cracked in the plane of the long axis of the photoreceptors. The cellular layers of the retina and the lateral surfaces of pigment epithelial cells were visualized. The four major types of frog photoreceptor were identified: red rod, green rod, single cone, and double cone. Cone myoids were observed to be contracted in light-adapted retinas and elongated in more dark adapted retinas.
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