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  • Immunocytochemistry  (223)
  • Scanning electron microscopy  (159)
  • Springer  (382)
  • Frontiers Media
  • National Academy of Sciences
  • 2020-2022
  • 1980-1984  (197)
  • 1975-1979  (146)
  • 1970-1974  (39)
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  • Springer  (382)
  • Frontiers Media
  • National Academy of Sciences
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 12 (1973), S. 313-321 
    ISSN: 1432-0827
    Schlagwort(e): Cathepsin D ; Extracellular ; Ossification ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Beschreibung / Inhaltsverzeichnis: Résumé De la cathepsine D extracellulaire d'origine principalement ostéoblastique a été démontrée par immunohistochimie dans le cartilage en voide de calcification de cultures d'os des membres d'embryons de poulet. L'intérêt de ce fait pour l'ossification est discuté.
    Kurzfassung: Zusammenfassung Es wurde mit einer immunohistochemischen Methode gezeigt, daß extrazelluläres Kathepsin D, welches hauptsächlich aus Osteoblasten gewonnen wurde, Knorpel von kultivierten Knochen von Kükenembryonen mineralisiert. Die Bedeutung dieser Feststellung für den Mechanismus der Knochenbildung wird diskutiert.
    Notizen: Abstract Extracellular cathepsin D derived mainly from osteoblasts has been demonstrated immunohistochemically in ossifying cartilage of cultured embryonic chick limb bones. The relevance of this observation to the mechanism of ossification is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 1432-041X
    Schlagwort(e): Vitellin ; Yolk granule ; Yolk protein ; Silkworm ; Embryogenesis ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Vitellin was purified from eggs of the silkworm,Bombyx mori, by a new method in which vitellin was extracted from isolated yolk granules. The purified vitellin had a molecular weight of 540,000. An antibody against purified vitellin was prepared in rabbits. It reacted with the hemolymph vitellogenin as well as with purified vitellin, but not with other proteins in the hemolymph or in the extract from yolk granules. The anti-vitellin IgG was used to immunocytochemically locate vitellin in theBombyx non-diapause egg during early developmental stages. In the egg, just after oviposition, vitellin was located in internal yolk granules and in small yolk granules of the periplasm. During the early developmental stages studied, vitellin was not metabolized uniformly throughout the egg. The vitellin of the internal yolk granules located at the posterior-dorsal part and of the small peripheral yolk granules was utilized in 16 h and 2 days, respectively, after oviposition. A thin, very vitellin-poor layer was located between the periplasm and the vitellin-rich interior in the newly laid egg. it was always in close contact with the periphery where blastoderm and germ-band cells developed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 191 (1982), S. 348-354 
    ISSN: 1432-041X
    Schlagwort(e): Dictyostelium ; Pattern Formation ; Scanning electron microscopy ; Chemotaxis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Scanning electron microscopic observations ofDictyostelium discoideum cell masses during slug formation revealed two populations around the anterior tip; one group of cells resembled elongated aggregation stream cells and their orientation suggested that they move to the tip, whereas the other group of cells were isodiametric and showed no obvious orientation. In seeking further evidence for a role of differential cAMP chemotaxis in the orientation and movement of slug cells the anterior prestalk cells were compared to the posterior prespore cells in two chemotaxis tests. When a cell mass is placed on cAMP agar the prestalk cells exhibited better movement to cAMP sources but when the gradient was generated in a diffusion chamber the prestalk cells did not. This evidence suggested that the cells which are better able to generate a cAMP gradient might form part of the anterior zone of the slug.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 189 (1980), S. 181-186 
    ISSN: 1432-041X
    Schlagwort(e): Xenopus embryo ; Scanning electron microscopy ; Cell shape ; Cilia formation ; Determination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Xenopus embryos held inverted from the one cell stage show a partial reversal of the pattern of cleavage: the blastocoel forms towards the new upper pole, and the non-pigmented cells forming the blastocoel roof are smaller than normal endoderm cells. Two properties of the cells from inverted embryos have been studied: their capacity to form cilia when cultured for 48 h, normally a property of ectoderm cells; and their scanning electron microscopical appearance when isolated and cultured for shorter periods, which differs for normal ectoderm and endoderm cells. Groups of the upper, non-pigmented cells from inverted embryos do not form cilia in a longerterm culture, whereas groups of the lower, pigmented cells do. In contrast, the scanning electron microscopical appearance of the upper, non-pigmented cells of inverted embryos is more like that of normal ectoderm cells; the appearance of lower, pigmented cells is more like that of normal endoderm. Thus the determination to form cilia is not reversed by inversion, whereas the control of cell morphology is.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1432-041X
    Schlagwort(e): Major haemolymph proteins ; Development ; Cuticle ; Immunocytochemistry ; Ceratitis capitata
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The developmental profile of the major haemolymph proteins (ceratitins) inCeratitis capitata was studied. Ceratitin concentration in the haemolymph decreases dramatically during the last days of pupal life, while the amounts of ceratitins in whole organism extracts remain unchanged. By electrophoretic, immunological and immunofluorescence techniques it was revealed that ceratitins are reabsorbed by the fat body and a fraction of them is deposited in the cuticle. The possible role of ceratitins is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 181 (1977), S. 31-40 
    ISSN: 1432-041X
    Schlagwort(e): Cell migration ; Mesoderm ; Gastrulation ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary At the end of gastrulation, the lateral mesoderm of amphibian embryos migrates ventrally between the ectoderm and the endoderm. The present study is an examination of the morphology of the leading cells of the mesodermal sheet and of the substratum over which they move (the inner surface of the ectoderm). The cells of the leading edge of the mesoderm are generally round, with very short and narrow flattened projections in the forward direction. These projections do not have a “ruffled” morphology, regardless of whether fixation is carried out before or after the ectoderm and mesoderm are dissected away from the endoderm. The inner surface of the ectoderm is covered with fine (450–500A) filamentous extracellular material and the ectoderm cells sometimes extend cytoplasmic processes (approx. 0.1 μ wide) onto the leading surface of the mesoderm or onto adjacent ectoderm cells. These studies indicate that the morphology of cell migration in amphibians is closer to that seen inFundulus than to that characteristic of chick or mammalian cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 27 (1979), S. 33-40 
    ISSN: 1432-0827
    Schlagwort(e): Chick embryo ; Bone ; Organ culture ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The study describes the ultrastructure of the mineralized portion of chick tibiae from 10 days in ovo to 2 days post-hatch. At 10 days a single mineralized cylinder surrounds the diaphysis. On its outer surface columnar trabeculae join to form ridges parallel to the long axis of the bone. These ridges are covered by another cylinder and form the haversian canals. At 11 days vascular invasion of the marrow cavity occurs and resorption of the endosteal surface begins. This type of periosteal deposition and endosteal resorption is repeated during and subsequent to embryonic development. The mineralized portion of 10-day chick tibiae cultured for 2 days in modified BGJ medium was compared with 10-, 11-, and 12-day tibiae in ovo. Cultured tibiae were similar in length and calcium content to 11-day tibiae in ovo. The form of mineral deposited in ovo and in culture was the same, namely, aggregates of spherical mineral clusters. Differences in culture included the following: (a) few concentric cylinders were deposited as compared with tibiae in ovo; (b) trabeculae were not arranged in rows and ridges in culture; (c) osteocytic lacunae were restricted to bases of trabeculae rather than uniformly distributed as in ovo; and (d) the endosteal surface of tibiae in culture appeared etched.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 30 (1980), S. 109-119 
    ISSN: 1432-0827
    Schlagwort(e): Oxalosis ; Human bone ; Scanning electron microscopy ; X-ray diffraction ; Oxalate titration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Postmortem scanning electron microscopy of human phalanges in a chronic uremic hemodialysis patient with hyperparathyroidism showed the presence of confluent abnormal rounded formations with a radial rosette-like crystalline pattern in the diaphysis as well as in the epiphyseal part of the bones. These fan-shaped configurations were found either as individual formations within bone trabeculae or as numerous aggregated crystalline deposits replacing large parts of the bone structure. The microdissected content of such large areas submitted to X-ray diffraction analysis revealed the predominant presence of calcium oxalate monohydrate or whewellite with some traces of hydroxyapatite. Oxalate titration analysis indicated the presence of 25% of oxalate, corresponding to 45% in weight of whewellite.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 26 (1978), S. 237-241 
    ISSN: 1432-0827
    Schlagwort(e): Epiphyseal chondrocytes ; Freezefracture ; Scanning electron microscopy ; Cell processes ; Membrane particles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Chondrocytes in epiphyseal cartilage were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) using freeze-fracture techniques. Freeze-fracture replicas showed large numbers of fingerlike, 0.11–0.15 μm diameter, projections from the chondrocyte surface, with numerous 95–180 Å diameter intramembranous particles associated with both the cell membrane surface and these projections. With SEM, these cytoplasmic projections were also obvious, but appeared collapsed into clusters of globular-shaped projections on the surface of the chondrocytes. With freeze-fracture techniques, in which shrinkage artifacts were essentially eliminated, the cytoplasmic projections were often seen in intimate contact with the extracapsular matrix. However, with chondrocytes prepared by both SEM and conventional TEM, there was evidence of shrinkage, the cytoplasmic projections having little contact with the extracapsular matrix. These findings show that the cytoplasmic processes are not artifacts of tissue processing and provide morphological evidence in support of the hypothesis that matrix vesicles are of cellular origin.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 25 (1978), S. 75-83 
    ISSN: 1432-0827
    Schlagwort(e): Rat ; Fluorosis ; Enamel ; Scanning electron microscopy ; Low temperature incineration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Sixteen 58-day-old male rats of Wistar strain, with a mean body weight of 179 g, were divided into two equal groups. Each group of eight animals was maintained for 70 days on drinking water, ad lib., containing no fluorine (control group) and 100 ppm of fluorine (experimental group). All specimens examined were obtained from the incisal portions of the incisors. The following types of enamel specimens were prepared for scanning electron microscopy: (1) acid-etched specimens; (2) acid-etched specimens followed by low temperature microincineration; and (3) fractured specimens. The enamel formed during high fluoride exposure showed marked hypocalcification, that is, the crystallite density in the prism core and interprismatic region was lower than that of control animals. The organic substances appeared to increase in these regions. These changes were prominent in the outer and middle enamel layers. Such changes following fluoride administration appear to indicate an inhibition of enamel maturation, that is, an inhibition of the mineral deposition and/or an inhibition of organic matrix withdrawal.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 24 (1977), S. 223-229 
    ISSN: 1432-0827
    Schlagwort(e): Enamel-cementum-morphology ; Immunocytochemistry ; Biochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The continuously erupting rabbit incisor tooth is normally thought of as having an enamel covered “crown” on its labial surface and a cementum covered “root” on its lingual surface. We have examined both surfaces of continuously erupting rabbit incisor teeth taken from near term embryos by a variety of means, including transmission and scanning electron microscopy, biochemical fractionation, and immunohistochemistry. In all cases, we could detect no qualitative difference in the early extracellular matrices taken from the labial and lingual surfaces of the teeth. Both matrices were shown to be composed of dentin and enamel, although the thickness and geometry of the enamel matrix on the lingual surface was somewhat different from that on the labial surface.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    ISSN: 1432-2048
    Schlagwort(e): Immunocytochemistry ; Lectin (localization) ; Phaseolus (lectin) ; Phytohemagglutinin ; Seed (lectin)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have examined the properties and subcellular localization of phytohemagglutinin (PHA), the major lectin of the common bean (Phaseolus vulgaris.), in the axis cells of nearly mature and imbibed mature seeds. On a protein basis the axis contained about 15% as much PHA as the cotyledons. Localization of PHA was done with an indirect immunolabeling method (rabbit antibodies against PHA, followed by colloidal gold particles coated with goat antibodies against rabbit immunoglobulins) on ultra-thin cryosections which were embedded in plastic on the grids after the immunolabeling procedure. The embedding greatly improved the visualization of the subcellular structures. The small (4 nm) collodial gold particles, localized with the electron microscope, were found exclusively over small vacuoles or protein bodies in all the cell types examined (cortical parenchyma cells, vascular-bundle cells, epidermal cells). The matrix of these vacuoles-protein bodies appears considerably less dense than that of the protein bodies in the cotyledons, but the results confirm that in all parts of the embryo PHA is localized in similar structures.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    ISSN: 1432-2048
    Schlagwort(e): Avena ; Immunocytochemistry ; Phytochrome
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Phytochrome of oat (Avena sativa L., cv. Garry) coleoptile cells in the red-light-absorbing form, Pr, is diffusely distributed while after conversion to the far-red-light-absorbing form, Pfr, it is observed only in very small areas within the cell. Comparison of phytochrome photoversibility measurements to the distribution of the pigment within the cell indicates that the spectral assay is not influenced by the observed compartmentalization of the chromoprotein. However, the observed compartmentalization of phytochrome is correlated with a loss in spectrophotometrically detectable Pr.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Planta 146 (1979), S. 203-210 
    ISSN: 1432-2048
    Schlagwort(e): Cellulose ; Microfibrils ; Negative staining ; Nicotiana ; Protoplasts ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A study has been made of the wall fibrils produced by tobacco protoplasts, using scanning electron microscopy in conjunction with negative staining. It has been shown that the fibres seen in scanning electron microscopy correspond to aggregates of microfibrils. These aggregates are only visible where they are lifted clear of the protoplast surface. Negative staining of fixed protoplasts shows that the aggregation of microfibrils into the fibres visible in scanning electron microscopy is probably produced by air-drying. Gentle disruption of microfibrils produces both random broken fragments and bundles of short pieces of fibrillar material about 60 nm in length. This material is present in undisrupted young walls, but not in undisrupted older walls. The microfibrils in young walls seem much more fragile and liable to breakage than those in older walls. These results are discussed in terms of the interpretation of scanning electron microscope images and the mechanism of cellulose microfibril formation by higher plants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    ISSN: 1432-2048
    Schlagwort(e): Cotyledons ; Endoplasmic reticulum ; Ferritin labeling ; Immunocytochemistry ; Phaseolus ; Protein (reserve) ; Reserve protein
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The ultrastructure of the storage parenchyma cells of the cotyledons of developing bean (Phaseolus vulgaris L.) seeds was examined in ultrathin frozen sections of specimens fixed in a mixture of glutaraldehyde, formaldehyde and acrolein, infused with 1 M sucrose, and sectioned at-80° C. Ultrastructural preservation was excellent and the various subcellular organelles could readily be identified in sections which had been stained with uranyl acetate and embedded in Carbowax and methylcellulose. The cells contained large protein bodies, numerous long endoplasmic reticulum cisternae, mitochondria, dictyosomes, and electron-dense vesicles ranging in size from 0.2 to 1.0 μm. Indirect immunolabelling using rabbit immunoglobulin G against purified phaseolin (7S reserve protein), and ferritin-conjugated goat immunoglobulin G against rabbit immunoglobulin G was used to localize phaseolin. With a concentration of 0.1 mg/ml of anti-phaseolin immunoglobin G, heavy labeling with ferritin particles was observed ober the protein bodies, the cisternae of the endoplasmic reticulum, and the vesicles. The same structures were lightly labeled when the concentration of the primary antigen was 0.02 mg/ml. Ferritin particles were also found over the Golgi bodies. The absence of ferritin particles from other organelles such as mitochondria and from areas of cytoplasm devoid of organelles indicated the specificity of the staining, especially at the lower concentration of anti-phaseolin immunoglobulin G.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 16
    ISSN: 1432-2048
    Schlagwort(e): Immunocytochemistry ; (PEP carboxylase) ; PEP carboxylase ; Sorghum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The localization of phosphoenol pyruvate carboxylase (EC 4.1.1.3.1.) in the leaf cells of Sorghum vulgare was investigated by using three techniques: the conventional aqueous and non aqueous methods gave conflicting results; the immunocytochemical techniques clearly showed that the enzyme is predominantly located in the cytoplasm of mesophyll cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 112 (1977), S. 123-126 
    ISSN: 1432-072X
    Schlagwort(e): Bandeiraea simplicifolia ; Schizosaccharomyces pombe ; Colloidal gold ; Cytochemistry ; α-Galactomannan-lectin ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Galactomannan was localized by scanning and transmission electron microscopy on the cells and cell walls of Schizosaccharomyces pombe. The markers were prepared from colloidal gold granules labelled with an α-galactopyranosyl-binding lectin isolated from the seeds of Bandeiraea simplicifolia. Part or all of this α-galactomannan was present in the outer layer of the cell wall and was uniformly distributed even on the fission scars.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 130 (1981), S. 189-194 
    ISSN: 1432-072X
    Schlagwort(e): Fuligo septica ; Myxomycetes, mycetozoans ; Acellular slime molds ; True slime molds ; Spore germination ; Swarm cell morphogenesis ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This report describes conditions under which spores of the acellular slime mold Fuligo septica underwent a very rapid, synchronous and complete (100%) germination followed by morphogenesis of motile, flagellated swarm cells from the released protoplasts. This developmental sequence was initiated immediately upon wetting the spores with a surfactant and was completed within 40–50 min in the absence of any exogenous nutrient other than sodium phosphate buffer. Oxygen was required for germination. The rate and percentage of germination diminished with increasing spore concentration suggesting the existence of an autoinhibitor. The morphological sequence of events in the differentiation process was examined by scanning electron microscopy.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 130 (1981), S. 307-311 
    ISSN: 1432-072X
    Schlagwort(e): Paracoccus denitrificans ; Cell surface ; Outer membrane ; Lysozyme ; Scanning electron microscopy ; NaCl treatment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of water washing and NaCl treatment on the cell surface of P. denitrificans were studied. Both treatments caused a release of material from cells. Chemical studies showed that NaCl treatment released material containing components characteristic of outer membrane. This treatment also increased the susceptibility of the organism to lysozyme. Scanning electron microscopy was used to monitor the effects of water washing and NaCl treatment on the cell surface. Both treatments were shown to alter the appearance of the cell surface. The disruptive effects of these procedures were found to be dependent upon the age of the culture.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 109 (1976), S. 9-14 
    ISSN: 1432-072X
    Schlagwort(e): Candida utilis ; Saccharomyces cerevisiae ; Colloidal gold ; Cytochemistry ; Mannan ; Plasma membranes ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The β(1→3)glucanase of Basidiomycete QM 806 was used to prepare Saccharomyces cerevisiae and Candida utilis protoplasts. Plasma membranes isolated from S. cerevisiae contained a small amount of mannose and traces of glucose and ribose. Randomly distributed α-mannan was detected by scanning electron microscopy at the surface of prefixed protoplasts using colloidal gold labelled with Concanavalin A as a marker. C. utilis protoplasts were also marked with anti-mannan antibodies. Again the distribution of mannan was random. This experiment indicated also that plasma membrane mannan has the same immunochemical determinants as cell wall mannan. It is hypothesized that mannan is mainly located in the outer layer of plasma membranes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 109 (1976), S. 31-35 
    ISSN: 1432-072X
    Schlagwort(e): Scanning electron microscopy ; Chlamydomonas ; Cell agglutination ; Cell fusion ; Flagella
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A technique has been developed by which mating gametes of Chlamydomonas eugametos can be studied in the Scanning Electron Microscope. A detailed description of the mating process, from the initial flagellar agglutination until the release of free vis-à-vis pairs, is presented. Flagella appear to agglutinate at random points on their surface. This is followed by a rapid increase of the contact area such that they “line-up” tip to tip. Flagella always exhibit a typical position prior to cell fusion. After cell fusion the flagella of a pair separate rapidly while the female have shortened about 33%. In a vis-à-vis pair the plasma bridge has contracted. The observations are interpreted in terms of a specific reorganization of the sexuale aggregate.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 22
    ISSN: 1432-072X
    Schlagwort(e): Candida tropicalis ; Cell surface ; Hydrocarbon transport ; Scanning electron microscopy ; Transmission electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The surface structure of the hypdrocarbon-utilizing yeast Candida tropicalis was investigated by scanning and transmission electron microscopy (SEM and TEM respectively). The sample preparation technique was based on a rapid cryofixation without any addition of cryoprotectants. In subsequently freeze-dried samples the surface structure was analysed by scanning electron microscopy. Thin sections were prepared from freeze substituted samples. Both techniques revealed hair-like structures at the surface of hydrocarbon-grown cells. The hairy surface structure of the cells was less expressed in glucose-grown cells and it was absent completely after proteolytic digestion of the cells. When cells were incubated with hexadecane prior to cyryofixation a contrast-rich region occured in the hair fringe of thin sections as revealed by TEM. Since these structures were characteristic for hexadecane-grown cells and could not be detected in glucose-grown or proteasetreated cells it was concluded that they originate from hexadecane adhering to the cell surface and are functionally related to hexadecane transport. The structure of the surface and its relation to hydrocarbon transport are discussed in view of earlier results on the chemical composition of the surface layer of the cell wall.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 107 (1970), S. 45-53 
    ISSN: 1432-0878
    Schlagwort(e): Retina ; Rat synaptic bodies ; Synaptic ribbon ; Extracellular material ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the synaptic bodies in the outer and inner plexiform layers of the rat retina was studied with scanning and transmission electron microscopy. The synaptic bodies in the outer plexiform layer are pear-shaped and their vitreal pole invaginated by processes from nerve cells. Their surfaces are covered with extracellular material, which is partly dissolved or redistributed during the fixation and rinsing procedure. The internal structure of the synaptic bodies is described. The synaptic bodies in the inner retinal plexiform layer are more difficult to identify with the scanning electron microscope. They are polyhedronal and also covered with extracellular material. The observations are discussed. The value of the application of two different preparation and analyzing methods, i. e. the scanning and the transmission electron microscopy, is stressed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 111 (1970), S. 346-363 
    ISSN: 1432-0878
    Schlagwort(e): Kidney ; Glomerulus ; Development ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Differenzierung der Podocyten wurde an Nieren 10 Tage alter Ratten raster-elektronenmikroskopisch untersucht und mit durchstrahlungs-elektronenmikroskopischen Befunden verglichen. Die Podocytenfortsätze können danach auf dreierlei Wegen gebildet werden: 1. Spalten innerhalb des Cytoplasmas lassen bandartige Cytoplasmabrücken entstehen. Diese gliedern sich weiter auf, bis zahlreiche miteinander verzahnte Fortsätze derselben Zelle entstanden sind. 2. Vom Zellrand her werden dicke Fortsätze weit vorgeschoben, die kleinere Fortsätze bilden. Durch sie können Verzahnungen mit entfernten Deckzellen entstehen. Die kleinen Fortsätze können sich jedoch auch mit anderen Fortsätzen der eigenen Zelle verzahnen. 3. Fingerförmige Fortsätze benachbarter Zellen verzahnen sich während ihrer Entstehung miteinander. Trotz zahlreicher desmosomenartiger Haftstellen zwischen benachbarten Podocyten entwickeln sich ihre Fortsätze und deren Verzahnungen anscheinend weitgehend autonom und nur selten nach den vermuteten Regeln epithelialer Nachbarschaft (Typ 3). Die Befunde sprechen vielmehr dafür, daß durchflutete und wachsende Glomerulumkapillaren die Podocytendifferenzierung induzieren und die Orientierung der Fortsätze beeinflussen.
    Notizen: Summary The differentiation of the podocytes was studied by scanning electron microscopy on kidneys of 10 days old rats. The results were compared with transmission electron microscopic pictures from the same kidneys. There are three ways of forming processes by the podocytes: 1. Slits within the cytoplasm give rise to cytoplasmic bridges which further divide themselves and finally build up a meshwork of processes within a cell. 2. Thick and sometimes very long processes originate from the cell border. Their smaller branches may interdigitate with those of distant podocytes or with other processes out of the same cell. 3. Finger-like processes of neighbouring cells interdigitate as soon as they develop. In spite of numerous desmosomal structures between neighbouring podocytes the cell processes and their interdigitations develop mostly independently from each other and only seldom after the expected rules of epithelial vicinity (type 3). These findings are interpreted as indication that flooded and growing capillaries induce the differentiation of podocytes and that they influence the orientation of their processes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 25
    ISSN: 1432-0878
    Schlagwort(e): Area postrema ; Peroxidase penetration ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Scanning electron microscopy and the penetration of horseradish peroxidase, especially from the ventricular surface, has been utilized to determine the distinctive properties of the posterior portion of the area postrema. This part of the organ is characterized by a non-ciliated surface composed of flattened cells, which appear less permeable to cisternally injected peroxidase than the ciliated ependymal cells covering the anterior part of the area postrema. However, more diffuse and rapid penetration of peroxidase into the posterior region is achieved by way of the perivascular spaces which appear in direct communication with the CSF. No such filling is noted in the anterior area postrema. The posterior portion also contains cells which appear to be rapidly penetrated by horseradish peroxidase and which may be important as a sensing mechanism. The chief distinction of the anterior part of the area postrema appears to be the presence of vascular connections with the choroid plexus.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 123 (1972), S. 82-95 
    ISSN: 1432-0878
    Schlagwort(e): Brain ventricles ; Choroid plexus ; Surface ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The surface of ependymal cells bordering the brain ventricles, and that of the epithelial cells of choroid plexuses of the cat have been investigated by means of the scanning electron microscope. The ventricle walls are entirely covered with very long and numerous cilia and no regional differences have been observed regarding their number and disposition. Among the ciliated cells dome-shaped structures are present, possibly containing nervous elements. The ependymal cells of the third ventricle floor are mainly non ciliated but the surface thereof shows numerous small microvilli. Numerous round formations are present among these cells, their nature being difficult to interpret. Also present on the floor are small cells of triangular shape with long and tortuous protrusions, tentatively identified as small neurons. The choroid plexuses have a typical sinuous structure of long tortuous villi rich in cavities and convolutions. Details of the epithelial cells covering the plexus and their surface organization are also reported.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 133 (1972), S. 147-162 
    ISSN: 1432-0878
    Schlagwort(e): Lymph node (dog) ; Reticulum ; Pulp ; Ultraarchitecture ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The perfused large mesenteric lymph node of the dog was observed under the scanning electron microscope. The lymph sinus contains reticulum cells which mostly are two-dimensionally formed stellate plates oriented in a uniform direction. Large round macrophages are loosely fixed by the reticulum cell processes. No intermediate type between both cells has been observed. Macrophages having a few long tentacle-like projections are densely covered by clubbed cytoplasmic processes. Smaller round cells, probably plasma cells and lymphocytes also remained in the sinus. The pulp of the node is built up by reticulum cells, much smaller than those in the sinus, and by densely packed round cells including a few macrophages. The trabeculae and the reticulum of the nodal parenchyme form a continuous structure.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 134 (1972), S. 105-127 
    ISSN: 1432-0878
    Schlagwort(e): Spermatozoon ; Sheep (Ovis ammon aries, L.) ; Surface fine structure ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei der Präparation von Schafspermien für die Beobachtung im Raster-Elektronenmikroskop wurden beigemengte Schleimstoffe durch zahlreiche Waschvorgänge mit schonender Zentrifugation und Behandlung mit Hyaluronidase weitgehend entfernt. Der Kopf des Spermium wird durch zwei bogenförmige Linien in drei Zonen unterteilt. In der vorderen Zone erhebt sich direkt hinter einem schmalen Randwulst symmetrisch die (dem apikalen Akrosomsegment entsprechende) apikale Sichel. Die äquatoriale Zone ist meist geringfügig über das Niveau der vorderen Zone erhaben; in ihrem medialen hinteren Bereich zeichnet sich ein lunulaähnlicher Bezirk mit granulierter Oberfläche ab. Die der hinteren Zone zugrundeliegende postnukleäre Scheide greift mit zahlreichen schmalen Fortsätzen in das äquatoriale Segment des Akrosoms; dazwischen gelegene Einsenkungen geben der Grenze beider Zonen ein sägezahnartiges Aussehen. Die Oberfläche der hinteren Zone weist viele grübchenförmige Einsenkungen auf. Caudal drückt sich der basale Gürtel in einem glatten bandförmigen Bereich aus. An der Kopfbasis umzieht der Ansatzwulst in ovalem Verlauf die Ansatzhöhle sowie die beiden hinteren Knöpfe. Am Schwanz des Spermium sind im Verbindungsstück zwei stärkere laterale Stranggruppen und zwischen ihnen zwei bzw. drei mediale gebänderte Stränge zu erkennen, die in der Tiefe der Ansatzhöhle aus dem Kapitulum entspringen. Das Mittelstück besitzt eine regelmäßige Schrägbänderung als Ausdruck seiner linksgewundenen mitochondrialen Tripelhelix; es schließt mit einem quergestellten Schlußring ab. Am Hauptstück sind neben einer queren Rippung drei längsverlaufende Wülste festzustellen, deren Stärke sich im Verlauf ändert. Das Endstück verjüngt sich in seinem Anfangsteil etwas; sein Durchmesser bleibt dann aber bis zum abgerundeten Schwanzende gleich.
    Notizen: Summary This investigation is concerned with the scanning electron microscopic appearance of sheep spermatozoa in comparison with details gained with the transmission electron microscope by earlier authors. The head of the spermatozoon is subdivided into three zones by two curved lines. In the anterior zone the apical sickle protrudes symmetrically behind a narrow marginal roll; the apical sickle corresponds to the apical segment of the acrosome. The equatorial zone is generally slightly elevated above the level of the anterior zone. In the medial posterior part of the equatorial zone a lunulalike area with granular surface is found. The posterior zone shows numerous small pitches; it corresponds to the post-nuclear sheath, which sends small processes into the equatorial segment of the acrosome. The surface view of this border between equatorial and posterior zone exhibits a saw-toothed appearance. A smooth tape-like area corresponds to the basal belt. At the base of the head an inserting-roll surrounds both posterior knobs and the implantation fossa. The connecting-piece of the sperm-tail consists of two lateral, and two or three, respectively, banded medial cords. These cords originate from the capitellum, which lies inside the implantation fossa. The middle-piece shows a periodical oblique pattern, which corresponds to the left-winded mitochondrial tripel-helix inside. The middle-piece reaches to a transverse terminal ring-like structure (annulus). The principal-piece shows periodically arranged transversal ribs as well as three longitudinal elevations. The latter are modified in the course of the principal-piece. The diameter of the end-piece decreases slightly in the anterior part; then it remains constant to the rounded tip.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 29
    ISSN: 1432-0878
    Schlagwort(e): Fourth ventricle ; Human ; Ependyma ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: 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
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 138 (1973), S. 31-39 
    ISSN: 1432-0878
    Schlagwort(e): Olfaction ; Fishes ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 200 (1979), S. 223-227 
    ISSN: 1432-0878
    Schlagwort(e): Hypothalamus ; Lacertilian reptiles ; Vasotocin neurons ; Mesotocin neurons ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The hypothalamic magnocellular neurosecretory system of lizards was studied with the unlabeled antibody peroxidase-antiperoxidase complex (PAP) technique at the light microscopic level. It was shown that vasotocin and mesotocin are synthesized in separate neurons. The vasotocinergic as well as the mesotocinergic perikarya are of different sizes. Both cell types occur in close juxtaposition, but without a distinct pattern of distribution. The external zone of the lacertilian median eminence contains numerous immunoreactive vasotocinergic fibers and only few immunoreactive mesotocinergic fibers. The general organization of the hypothalamic magnocellular neurosecretory system of lizards, as revealed by immunocytochemistry, is essentially similar to that revealed with unspecific staining methods.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 200 (1979), S. 285-290 
    ISSN: 1432-0878
    Schlagwort(e): Immunocytochemistry ; Ecdysteroids ; Prothoracic gland ; Insect hormones ; Galleria mellonella
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Fixation of prothoracic glands of Galleria mellonella with a solution containing saponin permits immunocytochemical staining of the entire gland. By this means ecdysteroids were demonstrated electron microscopically to be present in the hyaloplasm and microtubules.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 146 (1973), S. 543-552 
    ISSN: 1432-0878
    Schlagwort(e): Retinal pigment cells ; Retinal cell differentiation ; Retinal receptor cells ; Chicken ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 148 (1974), S. 69-82 
    ISSN: 1432-0878
    Schlagwort(e): Ultimobranchial glands ; Anuran larvae ; Metamorphosis ; Ultrastructure ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fine structure of ultimobranchial (UB) gland cells from Rana temporaria larvae 48 h after hatching until the completion of metamorphosis is described. A single UB cell type is present, believed to be the characteristic C cell, in which secretory granules are first detectable in 8 day post-hatching larvae. These secretory granules show an intimate association with lipid droplets. Unusual membranous and crystalloid inclusions, which may represent yolk platelets, are found in UB glands of very small larvae. The significance of a range of UB organelles is discussed and some scanning electron micrographs presented. This report is believed to be the first published ultrastructural and scanning electron microscope study of larval anuran UB glands.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 150 (1974), S. 389-397 
    ISSN: 1432-0878
    Schlagwort(e): Choroid plexus ; Human fetus ; Modifications during development ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructural organization of the human fetal choroid plexus was assessed with scanning electron microscopy. The membranous modifications of choroidal ependymal cells differ remarkably between 11 and 20 weeks of intrauterine development and suggest a variable functional capacity at different times of ontogenesis. Based upon existing data coupled with the ultra-architectural organization of cilia, clavate and linear microvilli are seen with scanning electron microscopy, a multiple functional role is hypothesized for choroidal ependymal cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 153 (1974), S. 151-165 
    ISSN: 1432-0878
    Schlagwort(e): Taste buds ; Fishes ; Chemoreceptors and Mechanoreceptors ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Within the epithelium of the head gut of the sword-tail (Xiphophorus helleri Heckel) there are three types of taste buds that can be identified with certainty in the scanning electron microscope. The breathing valves, which are situated behind the mouth region, bear relatively high epidermal papillae in which type I taste buds can be found. The middle region of the head gut is mostly occupied by low epidermal papillae containing type II taste buds. Type III taste buds are present within the metabranchial head gut; they never rise above the normal level of the epithelium. Taste buds of each type show two kinds of receptor villi within their receptor areas: tall villi (about 1,5×0,5 μm) and small villi (about 0.5×0.2 μm). A few tall villi belonging to solitary chemosensory cells are situated between the superficial epithelial cells of the tongue. In addition, the surface of the epidermal cells shows a delicate microridge system.—It is postulated that the taste buds of different types serve different functions: Taste buds within epidermal papillae may act both as chemoreceptors, and mechanoreceptors. Taste buds that never rise above the normal level of the epithelium perhaps act predominantly as chemoreceptors.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 37
    ISSN: 1432-0878
    Schlagwort(e): Luteinizing hormone-releasing hormone ; Hypothalamus ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Utilizing the unlabeled antibody enzyme method, we report the distribution of hypothalamic elements immunoreactive with antibodies to luteinizing hormone-releasing hormone (LH-RH) in the rat. Immunostained elements, resembling neural processes, were distributed along a pathway corresponding to the tuberoinfundibular tract which appeared to terminate near vascular elements in the external layer of the preand post-infundibular median eminence. No cell bodies stained specifically for LH-RH. Similar topographic arrangements were noted (in coronal and sagittal sections) in diestrous females, ovariectomized females and a hypophysectomized male. The same results were obtained with three different preparations of antisera to LH-RH. Our studies agree with those of other investigators using immunohistochemical techniques as well as with localization studies of LH-RH in the hypothalamus using bioassay and radioimmunoassay. Our results suggest that the unlabeled antibody enzyme technique will have unique value for identifying and tracing fiber systems related to specific functions within the hypothalamus.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 157 (1975), S. 457-465 
    ISSN: 1432-0878
    Schlagwort(e): Pecten oculi ; Pigeon ; Surface ; Function ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A scanning electron microscopic study of the pecten reveals the rib-like character of the pectinal folds, the nature of their connections with the base and bridge of the pecten as well as the presence of interconnections between the bundles of superficial collagenous fibres. It has been suggested that the pecten may have a mechanical significance, namely protection of the retina from the excessive movements of the vitreous humour. The relationship between the superficial membrane of the folds which is continuous, the intercellular spaces and the process of diffussion has also been discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 170 (1976), S. 145-159 
    ISSN: 1432-0878
    Schlagwort(e): Neurogenesis ; Retina ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Fixed retinae of chick embryos and chicks of the first week after hatching were fractured and examined with the scanning electron microscope. The matrix cells of the retina proliferate up to the beginning of the second week. The migrating cells are oriented in cell cords. This columnar organization prevails up to the development of the plexiform layers formed as a consequence of the outgrowth of the dendritic and axonal cell processes. Special attention was paid to the differentiation of the ganglion, bipolar and receptor cells, and the radial fibers (Müller cells). Two main morphological patterns are significant for the organization of the retina during neurogenesis: a) the cell to cell contacts of migrating cells and b) the spatial arrangement of Müller cells which could provide guidelines for migration of neuronal elements.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 159 (1975), S. 73-80 
    ISSN: 1432-0878
    Schlagwort(e): Osteoblasts ; Collagen orientation ; Parietal bone ; Rat, Rhesus monkey ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Bone was removed from the calvaria of anaesthetized 70 g rats or freshly killed young monkeys and the fibrous periosteum dissected off the inner, formative surface under 0.15 M cacodylate buffer. The bone and undisturbed osteoblasts were fixed in 3% glutaraldehyde in the same buffer for 24 to 48 hours, critical point dried and coated with evaporated carbon and gold for scanning electron microscopy (SEM). Fields of osteoblasts were photographed and chosen cells dissected off the osteoid using a tungsten needle. The control of the dissection was made possible by the use of a system of real-time stereo TV-speed SEM. The fields were rephotographed and the orientations of the osteoblasts were compared with that of the underlying collagen fibres. 62% of all osteoblasts lay with their long axes within 15° of the collagen fibre orientation below and 80% within 30°. Montages of large areas of osteoblasts were also made, and then compared with ones of the same area after the cells had been stripped off on adhesive tape. In general, the orientation of the collagen tended to be the same as the cell that formed it. Collagen fibres below cells at the periphery of a domain sometimes had the orientation of the cells in the adjacent patch. It is not possible to determine whether the cells controlled the orientation of the collagen, or vice versa, from this experiment, but other SEM evidence suggests that the collagen orientation in hard tissue matrices depends on the freedom of cells to move with respect to the matrix surface.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 159 (1975), S. 233-243 
    ISSN: 1432-0878
    Schlagwort(e): Odontoblasts ; Predentine ; Dentine ; Calcification ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A scanning electron microscopic technique was used to investigate the surface structure of dentinogenically active odontoblasts. Thin pieces of rat incisors were fixed, rapidly frozen, freezedried at -70° C and fractured to expose new surfaces prior to examination in the SEM. Differences in the appearance of odontoblastic cell surfaces were seen, with the most extensive ridge formations at the distal part of the sides of the odontoblasts. The predentine area displayed a spongy structure which contrasted to the compact appearance of dentine. Results are discussed in relation to previous studies at the light microscopic and transmission electron microscopic levels.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 160 (1975), S. 399-410 
    ISSN: 1432-0878
    Schlagwort(e): Lung ; Frog ; Alveolar epithelium ; Mucus layer ; Scanning electron microscopy ; Transmission electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Scanning and transmission electron microscopy were used to study the inner architecture of the frog lung. In some specimens the alveolar surface mucus layer was removed to permit the examination of underlying features. The inner surface of the frog's lung is covered by a layer of microvilli belonging to only one type of epithelial cells. The boundaries of these epithelial cells are demarcated by small ridges. Different degrees of lung expansion cause variations of the surface topography. The morphology of certain surface features is examined in detail. Several methods of drying the specimens are compared.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 161 (1975), S. 329-341 
    ISSN: 1432-0878
    Schlagwort(e): Spermatozoa ; Boar, bull, ram ; Surface ultrastructure ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé La morphologie comparée des spermatozoïdes éjaculés de Verrat, Taureau et Bélier a été étudiée au microscope à balayage. Le sperme lavé est fixé dans le glutaraldéhyde ou le mélange acide picrique-formaldéhyde-glutaraldéhyde. Les échantillons sont le plus souvent désséchés par la méthode du point critique (Fréon) sur un filtre et aussi dans l'air sur une lamelle de verre. La tête des spermatozoïdes de ces trois espèces présente la même forme en pagaie aplatie formée de trois régions principales: les deux segments, antérieur, entouré d'un épaississement marginal, et équatorial de l'acrosome et la région postacrosomique. La plupart des differentiations de la lame postacrosomique décrites en microscopie électronique à transmission sont visibles à travers la membrane plasmique, particulièrement après dessication à l'air. La morphologie superficielle du cou et des différentes parties du flagelle est aussi observable. Des différences spécifiques sont mises en évidence: chez le verrat seulement, par exemple, la surface de l'acrosome apparaît granuleuse, et aucune bordure antérieure dentelée de la lame postacrosomique n'est visible. La microscopie à balayage permet d'observer les grands traits et de fins détails de la morphologie superficielle d'un échantillon de sperme et aussi d'étudier les effects de traitements sur des spermatozoïdes (congélation, extraction de l'acrosome).
    Notizen: Summary The comparative ultrastructure of ejaculated boar, bull and ram spermatozoa is studied by scanning electron microscopy. After washing, the spermatozoa are fixed in glutaraldehyde or in picric acid-formaldehyde-glutaraldehyde mixture. Samples are prepared either by critical point drying (Freon) on Millipore filters or by air drying on glass cover slips. In all the species studied, three regions may be distinguished in the paddle-shaped head of the sperm: an anterior segment (surrounded by the marginal thickening) and an equatorial segment constituting together the acrosome, and the postacrosomal region. Most of the feature of the postacrosomal lamina described in transmission electron microscopy are visible through the plasma membrane, particularly after air drying. The surface morphology of the neck and of the different segments of the flagellum is also evident. Some species differences are encountered, e.g. rough surface of acrosome and absence of serrations in postacrosomal lamina of boar spermatozoa only. The techniques employed result in good general morphology and fine resolution of surface detail of the sperm samples; they also permit analysis of spermatozoa treated by freezing or submitted to acrosomal extraction.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 174 (1976), S. 129-137 
    ISSN: 1432-0878
    Schlagwort(e): Pineal organ, human ; Acervuli ; Scanning electron microscopy ; Transmission electron microscopy ; Electron probe microanalysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Untreated, decalcified and trypsinized acervuli from human pineal bodies were studied with the scanning and transmission electron microscope as well as by electron probe microanalysis. The mulberry-like acervuli are composed of a various number of spherical lobes (135–800 μm) between which clustered groups of globuli (4–14 urn in diameter) are observed. The acervular lobes are very probably formed by an aggregation of these globuli. Small round particles 125–500 Å in diameter are observed on the surface of the pineal concretions. These are not influenced by either decalcification or trypsin treatment. The acervular mineral corresponds morphologically to hydroxyapatite. The electron probe microanalysis reveals the existence of calcium and phosphorus as main components of the acervuli. Small quantities of magnesium and strontium were also detected.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 176 (1977), S. 493-504 
    ISSN: 1432-0878
    Schlagwort(e): Pancreas ; Acinar cells ; Cell surface ; Dissociation ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The pancreatic acinar cell surfaces have been studied by SEM with a dissection technique and correlated with results obtained by TEM. The SEM results demonstrate characteristic arrangement of microplicae which in some areas are densely packed. In many areas, the microplicae are distributed in such a manner that they create zones with typical geometrical shapes and show a relatively smooth surface. These smooth areas may coincide, as indicated by correlated TEM results, with the limits of intimate contact between adjacent acinar cells which, in turn, represent part of the junctional complex. Another aspect revealed by these SEM preparations concerns the presence of groups of densely packed microplicae, arranged in regular rows and distributed along some grooves and/or infoldings of the cellular surface. On the basis of SEM and TEM information, it is likely that these structures correspond to intercellular (and possibly, in some cases, intracellular) canaliculi which topographically form a kind of extensive microlabyrinthine arrangement running along all the cell sides. One final point revealed by fractured samples concerns the finding of spherical zymogen droplets within the vesicles of the Golgi complex. Because in many scanning images these vesicles appear connected by small openings, it is suggested that they may represent a system of intercommunicating chambers (vacuoles) through which the zymogen droplets can be continuously accumulated and discharged into the acinar lumen.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 177 (1977), S. 307-316 
    ISSN: 1432-0878
    Schlagwort(e): Third ventricle ; Mature monkeys ; Scanning electron microscopy ; Ependyma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Surface features of the ependymal lining of the third ventricle in mature male and female monkeys have been investigated with scanning electron microscopy (SEM). Broad aspects of third ventricular morphology from three species of monkey are similar regardless of sex. The lateral walls are heavily ciliated whereas the ventral floor and most ventral parts of the lateral walls are not. Clumps of cilia on the lateral walls are so dense that underlying surface details are usually obscured. There is a transition zone between the ciliated lateral wall and nonciliated ventral floor. The floor and lower part of the lateral walls of the third ventricle exhibit a characteristic polygonal pattern upon which surface specializations such as microvilli, blebs and polymorphous membrane protrusions are superimposed. Ependyma of the choroid plexus of the third ventricle also display membrane specializations. Supraependymal cells are more visible in nonciliated regions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 138 (1973), S. 585-589 
    ISSN: 1432-0878
    Schlagwort(e): Salmo gairdneri (Teleostei) ; Pineal organ ; Photoreceptor cells ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 136 (1973), S. 307-328 
    ISSN: 1432-0878
    Schlagwort(e): Ductus cochlearis ; Lizard ; Sensory hair cells ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 49
    ISSN: 1432-0878
    Schlagwort(e): Enkephalin neurons ; Vasotocin neurons ; Isotocin neurons ; Immunocytochemistry ; Goldfish (Carassius)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Our immunocytochemical investigation of the magnocellular neuroendocrine system in the goldfish hypothalamus reveals enkephalin (ENK)-containing neurons interspersed among the vasotocin (VT)- and isotocin (IT)-containing neurons of the preoptic nucleus. The perikarya of the ENK, VT, and IT neurons do not show distinct morphological differences at the level of light microscopy and are not located preferentially within the nucleus. Separate ENK, VT and IT fibers course laterally and ventrally through the hypothalamus as they descend toward the pituitary gland. All three fiber types form terminals around blood vessels in the neurohypophysis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 50
    ISSN: 1432-0878
    Schlagwort(e): Pancreatic polypeptide (PP) ; Neurones ; Central nervous system ; Peripheral nervous system, gut ; Immunocytochemistry ; Mammals ; Birds
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Pancreatic polypeptide (PP) is a candidate hormone of unknown physiological significance. It is produced by a population of endocrine cells in the pancreas. In the present study a PP-like peptide was found to occur in the mammalian and avian central and peripheral nervous systems. Immunoreactive nerve fibres and nerve cell bodies were widely distributed in the brain. Dense accumulations of nerve fibres occurred in the following areas: nucleus accumbens, interstitial nucleus of the stria terminalis, para- and periventricular hypothalamic nuclei, and medial preoptic area. In addition, nerve fibres were regularly seen in cortical areas. Immunoreactive perikarya were observed in the following regions: cortex, nucleus accumbens, neostriatum and septum. In the gut, immunoreactive nerve fibers were distributed in the myenteric plexus, in smooth muscle, around blood vessels, and in the core of the villi. Immunoreactive perikarya occurred in the submucosal and myenteric plexus, suggesting that PP immunoreactive nerves are intrinsic to the gut. In the species examined, the neuronal PP-like peptide could be demonstrated with an antiserum raised against avian PP, but not with those raised against bovine or human PP. Thus, neuronal PP is distinct from the PP that occurs in pancreatic endocrine cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 148 (1974), S. 83-96 
    ISSN: 1432-0878
    Schlagwort(e): Sharpey fibre bone ; Collagen orientation ; Mineralization ; Mammals ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Sharpey fibre bone specimens from cranial sutures and muscle attachment sites of rhesus monkeys and rats, and tooth sockets of several mammals (man, rhesus monkey and rat specimens mainly) were fixed, and either dried by critical point drying or freeze drying, or made anorganic with 1,2 ethane diamine or sodium hypochlorite, washed and airdried. The bone was examined by scanning electron microscopy. The packing density of the extrinsic fibres affected their cross sectional shape, the well separated fibres being the most uniform. Long parallel rows and groups of extrinsic fibres were observed. The fibre units that made up the Sharpey fibre bundles were sometimes distinct and mineralized as units. Mineralization was generally similar to the varied patterns encountered in root cementum. The diameters of the extrinsic fibres were similar at all sites and in all species; those in socket bone differed little from those in cementum. The intrinsic fibre orientation, although constant over fairly large areas, showed no consistent relation to the direction of entry of the extrinsic fibres. We would like to thank Mrs. E. Bailey and Mr. P. S. Reynolds for technical assistance.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 163 (1975), S. 125-132 
    ISSN: 1432-0878
    Schlagwort(e): Bovine subcommissural organ ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The bovine subcommissural organ was studied by using scanning electron microscopy. The most prominent finding was the existence of protruded and dilated endings of the ependymal cells. The majority of these cells were ciliated with two or more cilia; only a few unciliated cells were seen. Some pore-like structures were also seen on the surface. From the functional point of view, the most interesting finding was an amorphous heterogeneous material on the subcommissural ependyma. Especially in the caudal part of the organ this material accumulated in abundance. No real filamentous structures such as Reissner's fibre could be seen, however, it was assumed that the heterogeneous material corresponds to this formation. No supraependymal neurones were demonstrated.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 163 (1975), S. 313-325 
    ISSN: 1432-0878
    Schlagwort(e): Neurogenesis ; Cerebral cortex ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Fixed cerebral vesicles of mouse foetuses were fractured and examined with the scanning electron microscope. This method provides a study of the three dimensional developmental features of the pseudostratified columnar epithelium up to the formation of the early cortex plate. Matrix cells are a cell population of homogeneous shape, however, mitotic cells are easily identified by their spherical form. The external surface of the brain is formed by the closely packed end feet of these cells covered by a basal membrane. The formation of the cortical plate is the result of a continuous cell migration in columnar arrangement towards the pia. Glioependymal cells extend along the whole brain wall and most likely provide guidance for the migrating cell cords. The formation of the so-called migratory zone is a consequence of the growth of the basal and the horizontal prolongations of emigrating cells. The significance of the cell to cell contacts for the neuronal migration processes is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 54
    ISSN: 1432-0878
    Schlagwort(e): Pituitary ; Dexamethasone ; ACTH ; Autoradiography ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary 3H-Dexamethasone (10 μg/kg) was injected intravenously in adrenalectomized rats and after survival times of 5, 30, 60, and 180 min its uptake within the pituitary was studied by autoradiography. Radioactivity was concentrated in cell nuclei in the pars nervosa and pars distalis. Within the pars intermedia, only cells of the marginal zone were labeled. In the pars distalis, some cells showed a weak nuclear accumulation of radioactivity as early as 5 min after injection. The tissue radioactivity was nearly maximal at 5 min, and the proportion of radioactivity in nuclei reached a maximum of 60–70% by 30 min. In competition experiments, non-radioactive steroids (1 mg/kg) were injected 5 min before 3H-dexamethasone and sacrifice was 30 min later. Dexamethasone markedly diminished the nuclear accumulation in the pars distalis, but corticosterone and progesterone did not. In the pars nervosa, corticosterone and progesterone competed for nuclear uptake of 3H-dexamethasone, although less effectively than dexamethasone itself. Different cell types in the pars distalis were characterized by treating autoradiograms with an immuno-peroxidase bridge procedure. Cells treated with anti-ACTH 17–39 had the greatest nuclear concentration of radioactivity, and those stained with anti-TSH were least heavily labeled. Cells treated with antisera to GH, PRL, and hCG were moderately labeled.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 170 (1976), S. 1-16 
    ISSN: 1432-0878
    Schlagwort(e): Tissue culture cells ; Mycoplasma ; Light microscopy ; Transmission electron microscopy ; Scanning electron microscopy ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The host-parasite relationship of HeLa M cells artificially infected with a bovine species of Mycoplasma was studied by light microscopy, transmission electron microscopy and scanning electron microscopy. The use of morphometry to quantitate some of the findings was explored. The parasites were seen in locations extracellular to the cell surface. The detection of small numbers of organisms by light microscopy was well demonstrated by use of the fluorescent antibody technique. Scanning electron microscopy proved to be an excellent method for revealing the surface details of cell-parasite morphology. Ultra-thin sections showed that the parasites are aligned mostly parallel to the plasma membrane of the host cell but separated by a gap of 10 nm. Morphometry indicated an average of 69 organisms per cell surface occupying 1.7% of the surface area. An increase of 26% in diameter of the HeLa cells, possibly as a result of infection, was observed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 56
    ISSN: 1432-0878
    Schlagwort(e): Axons ; Scanning electron microscopy ; Neurones, afferent ; Nerve regeneration ; Spinal nerve roots
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Rat dorsal spinal nerve roots were cut and the tip on the ganglionic side of the cut was examined by scanning electron microscopy at 0, 7, 20 and 48 h after operation. Seven hours after cutting, free axonal sprouts had started to protrude from the cut end of the nerve. After 20 h the free sprouts were more profuse than at 7 h but were smaller and had a rougher surface. At both 7 and 20 h many of the sprouts consisted of a stalk 2–7 μm in diameter with a bulbous end 5–20 μm in diameter. A few branching sprouts were seen. At 48 h the sprouts were shrunken with a deeply furrowed surface. The significance of the surface structure of the sprouts is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 57
    ISSN: 1432-0878
    Schlagwort(e): Epididymal epithelium ; Castration ; Androgen-substitution ; Japanese monkey ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The caput epididymidis from castrated and androgen-supplemented, castrated Japanese monkeys was observed with the scanning electron microscope. The experimental findings were compared with the normal structures in control animals. The epididymal lumen of control animals was lined by a tall, pseudostratified columnar epithelium possessing long, slender stereocilia which were densely arranged in a tuft-like form. After castration, the epididymal epithelium was decreased in height to one-fifth of controls. The stereocilia were also considerably reduced in length and in number, resulting in a flattened epithelial surface with polygonal boundaries. Frequent projection of a long, single cilium from an epithelial cell into the lumen was also a prominent feature in the epididymal ducts of the castrated animals. Administration of testosterone to the castrated animals resulted in almost complete recovery of the epididymal epithelium as well as regeneration of the stereocilia which regained a tuft-like arrangement.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 58
    ISSN: 1432-0878
    Schlagwort(e): Rat posterior pituitary ; Neurophysin-vasopressinergic and neurophysin-oxytocinergic fibres ; Immunocytochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary By means of the unlabeled antibody peroxidase-antiperoxidase (PAP) technique at the electron microscopic level, it was demonstrated that the hormones of the neural lobe of the rat hypophysis are located in separate neurophysin-vasopressinergic and neurophysin-oxytocinergic nerve fibres. These observations confirm the results of our previous immunocytochemical studies at the light microscopic level.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 159 (1975), S. 379-385 
    ISSN: 1432-0878
    Schlagwort(e): Compound eye ; Musca domestica ; Ommatidium ; Distal retinula ; Scanning electron microscopy ; Corneal lens ; Corneal pigment cell ; Pseudocone ; Semper cell ; Basement membrane
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distal aspect of the housefly ommatidium was surveyed by the scanning electron microscope. Attention was directed to the somal eminence of the superior central cell and the lens to large pigment cell junction. The underside of each lens facet exhibits six hexagonally arranged incisures. Into each of these indentations are fitted several large pigment cells. This hexagonal indentation appears to be a tenacious anchorage. Two corneal pigment cells laterally encircle the pseudocone and at their proximal extension they enclose the Semper cells and neck of the retinula. The somal eminence of the superior central cell is about 10 μm from the base of the corneal pigment cell enclosure. Micrographs were used to construct a diagram of the ommatidium above the basement membrane. Suggestions are made as to the functional correlates of the observed ommatidial structures.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 60
    ISSN: 1432-0878
    Schlagwort(e): Growth hormone-release inhibiting hormone ; Somatostatin ; Hypothalamus ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Utilizing the unlabeled antibody enzyme method, we investigated the distribution of hypothalamic elements immunoreactive with antibodies to growth hormonerelease inhibiting hormone (GH-RIH). Immunostained elements, resembling neural processes, are distributed along a pathway corresponding to a portion of the tuberoinfundibular tract. However, GH-RIH fibers are caudal, dorsal and medial to LH-RH fibers detected by the same technique. Similar topographic arrangements are noted in coronal and sagittal sections. Comparable results were obtained with two different preparations of antisera to GH-RIH. No cell bodies specifically stained by anti-GH-RIH were detected. Our data agree with those of other investigators using immunohistochemical techniques.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 172 (1976), S. 379-388 
    ISSN: 1432-0878
    Schlagwort(e): Chitons ; Receptors ; Shell surface ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The shells of the chitons Lepidochitona cinereus, Sypharochiton pelliserpentis, Amaurochiton glaucus and Onithochiton neglectus were examined by scanning electron microscopy. In all species the surface terminations of the megalaesthete and micraesthete organs could be identified lying flush with the shell surface, as well as, lenses of the shell eyes in O. neglectus. Periostracal debris and encrusting diatoms were a usual feature of the shell surfaces. The micraesthete subsidiary caps normally appear featureless, but the megalaesthete apical caps sometimes appear to be perforated. The reasons for this perforate appearance are discussed and it is concluded that it provides no evidence for the normal passage of substances out of or into the megalaesthete.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 62
    ISSN: 1432-0878
    Schlagwort(e): Hypothalamo-adenohypophysial region Bufo bufo (L.) ; Portal vessels ; Methyl-methacrylate casts ; Light microscopy ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The vascularization of the hypothalamo-adenohypophysial region of the toad Bufo bufo (L.) (Amphibia, Anura) was studied by means of light- and scanning electron microscopy. Special attention was given to the portal vascular system of the median eminence and the pars distalis. Course and arrangement of these vessels are described.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 162 (1975), S. 377-385 
    ISSN: 1432-0878
    Schlagwort(e): Globiferous pedicellariae ; Psammechinus miliaris ; Microvilli ; Chemoreceptor ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The globiferous pedicellariae of Psammechinus miliaris are described. Two fixation methods giving minimal distortion and rapid tissue hardening were adapted for soft tissue preparation for scanning electron microscopy. The pedicellarial valves are covered by a microvillous epithelium. The outer valve epithelial microvilli overlying red spherulocytes in the epidermis are characterized by a filament matrix radiating out from each microvillus. These microvilli may function in epidermal absorption of organic solutes. The inner valve microvilli are more densely packed and the filament matrix is absent. Ciliation is confined to the inner valve surface where the cilia are concentrated to form a distal sensory pad and sensory hillock. Behavioural evidence suggests a chemo- and mechanosensory role for the inner valve surface.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 164 (1975), S. 371-385 
    ISSN: 1432-0878
    Schlagwort(e): Kupffer cell ; Endothelial cell ; Sinusoid ; Liver ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The surface ultrastructure of Kupffer cells in the rat liver has been studied by scanning electron microscopy (SEM). The results demonstrate that Kupffer cells are both significantly different and clearly distinct from endothelial cells. Kupffer cells have neither pores (and/or “sieve plates”) nor fenestrations, all of which are present in endothelial cells. They possess a stellate shape, and only indirectly, with slender and irregular evaginations, contribute to the lining of the sinusoidal wall. Furthermore, the luminal surface in some areas contains a large population of short microvilli, microplicae and invaginations. These elements form a kind of microlabyrinth which may correspond to the “worm-like” structures described by transmission electron microscopy (TEM). In the present study, transition forms between endothelial and Kupffer cells were never found. On the contrary, considering the highly fenestrated nature of the endothelial cells, the Kupffer cells may, by ameboid movements, easily cross the overlapping barrier of the sinusoid and protrude into the lumen. Thus, acting as activated macrophages, the Kupffer cells might function to prevent the entrance of foreign material into the tissues of the liver through the fragile and highly fenestrated endothelium. Finally, the topographical reconstruction of the sinusoid by correlated SEM and TEM studies demonstrates that Kupffer cells, with their protruding cytoplasm and ability to extend into the lumen of the sinusoid, may actually change the caliber of the vessel, and thus function as a “sphincter” which causes a temporary arrest of the blood flow when the diameter of the sinusoidal lumen is reduced.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 65
    ISSN: 1432-0878
    Schlagwort(e): Neuromuscular junctions ; Appendicularia (Oikopleura dioica) ; Connective tissue fibrils ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Critical point dried and fractured appendicularia of the species Oikopleura dioica have been examined in the scanning electron microscope. The dorsal nerve cord with ganglion cells and peripheral nerve fibres could easily be observed. Thick peripheral nerve fibres leave the nerve cord as bilateral pairs at constant intervals along the tail. Most of these fibres branch from the naked nerve cord, but some evidently originate in ganglion perikarya bulging out from the nerve cord itself. These paired peripheral nerves always have elaborate end-arborizations on the medial surface of the lateral muscle cells. They are accordingly interpreted as motor axons. Some thinner peripheral nerve fibres originate at irregular intervals from both the nerve cord and the ganglion cells. Due to the numerous extracellular fibrils that connect the bilateral layers of the epidermal fins and the muscle cells to each other, these thin nerve fibres can seldom be traced to their termination. A few ones can, however, be traced ventrally between the notochord and the muscle cells and seem to end in singular bulb-like expansions. Clusters of synaptic vesicles are present in transmission electron micrographs of such nerves, and they are accordingly believed to carry efferent impulses. The extracellular fibrils are arranged in a highly ordered pattern with thick bundles crossing the gap between the structures to be interconnected and with numerous radiating insertions on the surface of the tissues.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 166 (1976), S. 25-35 
    ISSN: 1432-0878
    Schlagwort(e): Pituitary gland ; Cell types ; Estrogen ; Autoradiography ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Dry-mount autoradiography was combined with peroxidase immunocytochemistry to examine estrogen uptake in four pituitary cell types. Quantification by silver grain counts was used to compare 3H-estradiol uptake in nuclei of pituitary cells 60 min after i.v. injection into short-term (control) and long-term ovariectomized and in long-term thyroidectomized rats. Under all three hormonal states, the order of labeling intensity was: gonadotropes 〉 somatotropes 〉 lactotropes 〉 thyrotropes. Long-term ovariectomy caused a significant increase in estrogen uptake of gonadotropes, somatotropes and lactotropes, while uptake in thyrotropes decreased. Long-term thyroidectomy decreased uptake in somatotropes, lactotropes and thyrotropes while gonadotropes remained unchanged.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 166 (1976), S. 65-70 
    ISSN: 1432-0878
    Schlagwort(e): Collagen ; Bone ; Cell culture ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Embryonic and young rat bone cells have been grown in culture and examined in the scanning electron microscope (SEM). Compared with cells fixed in situ and taken directly from the animal, the cultured osteoblastic cells were smoother, flatter and more extensive and showed tighter intercellular contacts. Some matrix is formed in culture and undergoes at least partial mineralization as judged by the accumulation of Ca and P measured by energy dispersive x-ray analysis. Findings concerning the morphology of the collagen arrangement were indecisive. Some superficial cells, free of surrounding matrix, resembled osteocytes in normal in vivo bone. This may indicate that a proportion of the extracellular matrix produced by the cultured cells failed to polymerise into recognizable bone matrix, and that osteocytic morphology is not dependent upon the physical characteristics of the bone matrix.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 68
    ISSN: 1432-0878
    Schlagwort(e): Nerve growth factor ; Submandibular gland mice ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Nerve growth factor (NGF) was localized in the submandibular gland of adult male mice by a direct immunocytochemical method using highly purified antibodies against NGF coupled to horseradish peroxidase. In light microscopic sections the reaction product was entirely confined to the cells of the secretory tubules. The acinar part of the gland was free of reaction product. This finding was confirmed by electron microscopy. Within the cells NGF was localized exclusively in the apical secretory granules. No reaction was observed in the rough endoplasmic reticulum, the Golgi region or in the granules of the basal part of the cells. This observation favours the assumption that NGF is derived from a precursor molecule and that the precursor is transformed into immunologically active NGF within the secretory granules during their transport from the basal to the apical part of the tubular cells. Stimulation of the submandibular gland with carbachol (2 mg/kg) led to a massive release of the content of the secretory granules, including NGF, into the salivary duct.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 69
    ISSN: 1432-0878
    Schlagwort(e): Luteinizing hormone-releasing hormone ; Median eminence ; Electron microscopy ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary LH-RH was localized at the ultrastructural level in axons and nerve terminals of the median eminence of the male guinea pig. LH-RH positive neuronal profiles were most concentrated in the medial-dorsal aspect of the infundibular stalk and in the post-infundibular median eminence at the level immediately following separation of the stalk from the base of the brain. LH-RH containing axon profiles were most abundant in the palisade zone; nerve terminals in contact with the hypophysial portal vasculature were relatively rare. The hormone was present within granules that measured 900–1,200 Å in axons of the palisade zone and 400–800 Å in nerve terminals abutting on the portal plexus. The differently sized granules represent heterogeneous populations.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 169 (1976), S. 277-287 
    ISSN: 1432-0878
    Schlagwort(e): Rabbit gametes ; Cryofractography ; Scanning electron microscopy ; Transmission electron microscopy ; Zona pellucida
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Rabbit ova fertilized in vitro were prepared for scanning electron microscopy by ethanol-cryofracturing and critical-point drying methods and were also embedded and sectioned for transmission electron microscopy. Study of a region of interaction between sperm and zona pellucida with scanning electron microscopy reveals the latter to be composed of a complex network of fibers interspersed with numerous pores. Transmission electron microscopy of the same region reveals a “typical” homogeneous composition of the zona pellucida. Ultrastructural observations of thin sections passing through the region of sperm-egg interactions or through other regions of the ovum or its investments reveals very little methodological distortion of the various intracellular organelles or matrix. Application of the procedures described provides not only an elucidation of surface detail but also reveals intracellular cytoplasmic information about the same specimen during in vitro fertilization.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 169 (1976), S. 449-465 
    ISSN: 1432-0878
    Schlagwort(e): Bone ; Osteoblasts ; Cell surface ; Cell shape ; Calcitonin ; Parathyroid extract ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Neonate rat endocranial osteoblasts were cultured on their bone surfaces in control medium (CC) or medium to which either parathyroid extract (PTE) or calcitonin (CT) had been added for 2, 4, 8 or 24 h. Some were cultured for 24 h in CC, then for 2, 4, 8 or 24 h in either CT or PTE medium; or for 24 h in PTE, then for 2, 4, 8 or 24 h in either CC or CT; or 24 h in CT and 2, 4, 8 or 24 h in CC. The dorsal ruffling of the cells in CC was found to be suppressed by later culturing with PTE and the disoriented cells reorganized to form arrays of parallel cells. The effects of PTE were also reversed by CC or CT: the osteoblasts in the second culture (CC) lost elongation and order, and proceeded through a proliferative phase before exhibiting the ruffling form similar to a single CC 24 h culture. PTE-cultured osteoblasts showed an increase in cell overlap and contact so that a more competent barrier was formed separating the bone from the medium. In control or CT medium, however, intercellular gaps were greater than in vivo.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 119 (1971), S. 534-551 
    ISSN: 1432-0878
    Schlagwort(e): Isolated nerve fibres ; Neurokeratin ; Nodes of Ranvier ; Demyelination ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The surface morphology of normal myelinated nerve fibres prepared in different ways for scanning electron microscopy has been studied and compared with the surface features of similar fibres undergoing retrograde changes. Nodes of Ranvier, paranodal specializations, artefactual fractures of the myelin, and the endoneurial collagen sheaths are described. A regular pattern of elevations, usually with a pitted or depressed surface seen on normal myelinated fibres after certain preparative procedures are thought to be artefacts produced during preparation and to be related to the neurokeratin network. Alterations in the surface structure of fibres central to long-standing nerve transections include irregular protuberances, serial surface corrugations and large swellings, all associated with demyelination. Fibres that have undergone retrograde degeneration consist of endoneurial tubes with focal swellings occupied by macrophages or myelin debris, together with fine unmyelinated and small myelinated regenerating axons. Strict centrifugal progression of myelination of regenerating axons was not observed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 128 (1972), S. 336-346 
    ISSN: 1432-0878
    Schlagwort(e): Olfactory organ ; Sea trout ; Morphogenesis ; Ecological adaptations ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Scanning electron microscopy has been employed to study the central axis and laminae of the olfactory rosette in adult sea trout (Salmo trutta trutta L.) caught in the River Umeälven when they were homing from sea.—Both flat sides of the primary laminae are secondarily folded all over their surface. In one organ there are about 200 secondary laminae usually arranged in longitudinal, parallel ridges crossing the surface of the primary laminae. Initially they are covered with sensory epithelium, but as the folds grow they become covered with an increasing area of indifferent ciliar epithelium with bushes of cilia separated by microvilli cells and goblet cells. Parts of the central axis and primary laminae have a nonciliar indifferent epithelium. The sensory epithelium has irregularly arranged cilia. Like those of the indifferent epithelium they have uniform thickness and granulated surface. The function of laminae, secretion and cilia is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 74
    ISSN: 1432-0878
    Schlagwort(e): Olfactory mucosa ; Olfactory receptors ; Fish ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 142 (1973), S. 515-524 
    ISSN: 1432-0878
    Schlagwort(e): Arteriovenous anastomoses ; Carotid body ; Cat ; Corrosion casting technique ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 76
    ISSN: 1432-0878
    Schlagwort(e): Pituitary gland ; Axolotl ; Glycoprotein hormones ; Corticotrophs ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Les anticorps anti-TSH (hormone thyréotrope) d'origine bovine, anti-LH β (hormone lutéinisante) d'origine ovine et anti β (1–24) corticotropine de synthèse ont été appliqués à l'hypophyse de l'Axolotl (Ambystoma mexicanum, Shaw) selon une technique d'immunofluorescence histologique indirecte. Les anticorps anti-TSH se fixent sur une population de cellules fusiformes localisées dans les régions caudale et ventrale de l'hypophyse distale. Les éléments révélés par les anticorps anti-LH β possèdent un noyau ovalaire entouré d'un cytoplasme intensément fluorescent et sont répartis dans l'ensemble du lobe hypophysaire distal. Les cellules fixant l'anticorps anti β (1–24) corticotropine sont disposées en bordure de l'éminence médiane et présentent un noyau ovalaire et un cytoplasme abondant. Il s'agirait respectivement des cellules à fonction thyréotrope, gonadotrope et corticotrope. L'examen des caractéristiques cytologiques et histochimiques de ces trois types cellulaires complète ces données immunologiques.
    Notizen: Summary Antisera prepared respectively against TSH (thyreotropin) of bovine origin, against LH (luteotropin) of ovine origin and against synthetic β (1–24) corticotropin were applied to histological sections of Axolotl pituitary (Ambystoma mexicanum, Shaw) with the indirect immunofluorescence procedure. The anti-TSH antibodies from the first antiserum attach themselves to a population of fusiform cells situated in the caudal and ventral areas of the pars distalis. The cells revealed by the second antiserum show an oval nucleus surrounded by a strongly fluorescent cytoplasm. They are scattered throughout the whole pars distalis. The cells revealed by the third antiserum are arranged around the median eminence. Their nucleus is oval and their cytoplasm abundant. Presumably, these three cell types correspond respectively to the thyreotropic, gonadotropic and corticotropic cells as indicated by a parallel examination of their cytological and histochemical characteristics.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 106 (1970), S. 209-219 
    ISSN: 1432-0878
    Schlagwort(e): Skin ; Internal surfaces ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The scanning electron microscope has been used to investigate the surfaces of epidermis, hair follicles, fat cells, glands and blood vessels in sections of human skin. The appearances of structures associated with these surfaces have been described. The results demonstrate that this new instrument can become an important tool in the investigation of surface changes that might accompany the application of loads (extensive, compressive or torsional), or physiological or pathological abnormalities.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 147 (1974), S. 149-156 
    ISSN: 1432-0878
    Schlagwort(e): Sensorysur face ; Tentacles ; Sea anemones ; Corals ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Examination of the sensory surface of the tentacles of sea anemones and corals prepared by the Freon critical-point method has revealed three primary structures: ciliary cones consisting of a cilium surrounded by a cluster of shorter stereocilia, single long cilia, and microvilli. The ciliary cones occur on, and the single cilia and microvilli occur both on and between, the nematocyst- and spirocyst-bearing regions of the tentacles. The similarity of the anthozoan ciliary cones to the ciliary sensory structures in the lateral line, and the auditory and vestibular organs of vertebrates is noted and the possible functional significance of the coelenterate structures is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 170 (1976), S. 263-273 
    ISSN: 1432-0878
    Schlagwort(e): Fetal pituitary ; Cell differentiation ; Immunocytochemistry ; Tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Adenohypophysial primordia of rat embryos at 13 to 15 days gestation were cultured in Parker 199 synthetic medium for 2 to 11 days. At the end of the culture period their fine structure and the presence of immunoreactive trophic hormones using the peroxidase-labeled antibody technique were investigated. The degree of differentiation in the glands depends largely on the age of the embryos furnishing the explants. Cultured pituitaries explanted on the 13th day of gestation contain only ACTH-positive cells and about 15% of the cells are granular. The granules are 50–100 nm in diameter in some cells, while in other cells they range from 50 to 200 nm. In cultivated adenohypophysial primordia of embryos on the 15th day of intrauterine life ACTH, prolactin, LH and TSH cells are evident, but only the same two kinds of granular cells can be observed with the electron microscope. The extent of cytodifferentiation in the glands explanted on the 14th day of gestation is intermediate between the two other groups. The data suggest that the fetal rat pituitary has the capacity of self-differentiation but to a lesser extent than that of the in situ hypophysis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 80
    ISSN: 1432-0878
    Schlagwort(e): Neurophysin ; Vasopressin ; Median eminence ; Electron microscopy ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary With the use of tissue prepared by freeze-substitution and the unlabelled antibody enzyme technique, neurophysin and vasopressin were localized at the ultrastructural level in the posterior pituitary and median eminence of the guinea pig. In the posterior pituitary neurophysin was found in the large neurosecretory granules (1300–1500 Å) of axons, Herring bodies, and nerve terminals. In some of these axons immunoreactive neurophysin was found outside of granules in the axoplasm. By light microscopy neurophysin was found in both the zona interna and zona externa of the median eminence; this was confirmed by electron microscopy. In the zona interna as in the posterior pituitary, neurophysin was localized both inside and outside the large neurosecretory granules. In the zona externa, immunoreactive deposit was primarily located in granules with a diameter of 900–1100 Å in nerve terminals abutting on the primary portal plexus. The distribution of vasopressin paralleled that of neurophysin except that the hormone was rarely extragranular. These results demonstrate for the first time that both neurophysin and vasopressin are present in granules of axons that are in contact with the hypophysial portal vasculature.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 81
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 164 (1975), S. 467-471 
    ISSN: 1432-0878
    Schlagwort(e): Pancreas ; Islets ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The surfaces of isolated pancreatic islet cells were studied with the scanning and transmission electron microscopes. Islets were isolated from the pancreas of Wistar rats by collagenase treatment and were incubated either in glucose-free medium or in 300 mg% glucose for one hour. Immunoreactive insulin (IRI) in the media of both control and experimental preparations was assayed. Islets were then transferred to 4% glutaraldehyde, buffered with cacodylate, pH 7.4, and prepared for scanning and transmission electron microscopy. Cell masses average 200 μ in diameter. Alpha cells appear pyramidal in shape, are about 8 μ in diameter and appear in groups. Beta cells are round or oval in shape and have an average diameter of 10 μ. Glucose stimulation raised the IRI value tenfold and increased the number of blebs and other surface irregularities per unit area of beta cell surface. Comparison with transmission electron micrographs suggests that the blebs are related to the process of emiocytosis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 164 (1975), S. 543-557 
    ISSN: 1432-0878
    Schlagwort(e): Magnocellular hypothalamic nuclei ; Fetal and neonatal pigs ; Anti-porcine neurophysin serum ; Immunocytochemistry ; Slab gradient polyacrylamide gel electrophoresis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The immunoperoxidase cytochemical reaction was applied to the localization of neurophysin-containing elements in the fetal and adult pig hypothalamus. In the 60 day fetal pig, cells of the supraoptic nucleus (SON) were the only structures in the hypothalamus in which neurophysin was detected. However, by 87 days the cell bodies in both the SON and paraventricular nucleus (PVN) contained neurophysin-like material. The distribution of immunoreactive material in the 111 day fetal animal was similar to that found in the adult pig. In transverse section of the mature pig the SON exists in two discrete components; an antero-lateral group of cells connected by scattered cells to a smaller postero-medial group. Anteriorly, the PVN appears as a line of cells bordering the third ventricle but as we proceed posteriorly the dorsal aspect expands laterally to give a wedge-shaped group of cells. In mid-sagittal sections, the cells of the PVN are distributed over a wide area of the anterior hypothalamus in a triangular profile. The borders between the SON and PVN became more difficult to define in medial sections than in lateral sections. Continuous gradient polyacrylamide gel electrophoresis was carried out on the neural lobe extracts from fetal, newborn and adult pigs. Proteins with an electrophoretic mobility similar to that of porcine neurophysins-I,-II and -III were present in the newborn and 98 day fetal pig. It is concluded that material immunoreactive with anti-neurophysin serum is present in the hypothalamus of the 60 day fetal pig. Furthermore, at late fetal development and during the postnatal period it is tentatively suggested that the neurophysin present in the pituitaries of these animals is chemically identical with that of adult neurophysin.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 166 (1976), S. 91-100 
    ISSN: 1432-0878
    Schlagwort(e): Kidney (rat) ; Uriniferous tubule ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fine structure of luminal surface of clearly identified portions of uriniferous tubules has been studied by scanning electron microscopy to elucidate some controversies concerning the topography of certain surface formations. The results show a characteristic pattern of the luminal surface in the region of Henle's loop, which was assumed by previous authors, to belong to the collecting tubule. Furthermore it is demonstrated that no cilia are present within the terminal portion of the collecting tubules.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 174 (1976), S. 499-518 
    ISSN: 1432-0878
    Schlagwort(e): Fibroblast ; Human ; Transmission electron microscopy ; Scanning electron microscopy ; Aggregation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The different stages during aggregation of diploid human skin fibroblasts have been examined by transmission and scanning electron microscopy. As a result of aggregation, fibroblasts form a complex tissue configuration. Numerous intercellular junctions can be observed, while the cells remain polygonal and do not develop an organised intracellular cytoskeleton. Cell division occurs only rarely. After aggregation, signs of progressive auto-digestion develop. Adhesion to a substrate results in outgrowth of the cells and monolayer formation, even when extensive cell damage had occurred. The morphology of fibroblasts in aggregates and in the monolayers, from which they were derived, is compared and the contribution of the aggregate system to the study of fibroblast behavior is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 85
    ISSN: 1432-0878
    Schlagwort(e): Amphibian hypothalamus ; Vasotocinergic and mesotocinergic neurons ; Neurophysins ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Using the unlabeled antibody peroxidase-antiperoxidase (PAP) technique at the light microscopic level, it was demonstrated that, in the amphibian magnocellular hypothalamo-hypophysial neurosecretory system, vasotocin and mesotocin are synthesized in separate neurons. A tendency to preferential location of the two kinds of neuronal perikarya is described. The neurosecretory perikarya are the origin of separate vasotocinergic and mesotocinergic axons. In the neural lobe, the pattern of distribution of the two types of axons is different. The coarse ventricular “dendrites” of both kinds of neurons are hormone-containing processes. Staining with anti-bovine neurophysin I serum suggested that the vasotocinergic and the mesotocinergic neurons synthesize different neurophysins.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 166 (1976), S. 299-314 
    ISSN: 1432-0878
    Schlagwort(e): Renal glomerulus (Rat) ; Endothelial cells ; Blood capillaries ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The rat kidney was perfused with saline and glutaraldehyde, treated with Murakami's tannin-osmium impregnation method, ethanol-freeze cracked and dried by the critical point method. Gold-palladium evaporated specimens were observed in a field-emission scanning electron microscope. The glomerular filtration membrane, fractured in different planes was observed with the following results: 1. Adjacent pedicles originate from different podocytes. No interpedicular bridges of apparent cytoplasmic nature could be found. 2. The basement membrane, in grazing fractures shows a horizontally layered architecture. 3. The attenuated endothelial sheet (lamina fenestrata) is divided into compartments, which we suggest should be called “areolae fenestratae”, by cytoplasmic crests radiating from the nucleated portion of the endothelial cell. A crest also occurs along the cell margin, which contacts a similar crest at the margin of the adjacent cell. 4. The pores in the areolae fenestratae are variable in size (30−150 nm diameter). A knob-like projection from the apparently naked basement membrane is found in a portion of the pores. 5. Numerous microvilli may occur on the endothelium. Some of them anastomose and fuse with one another to form a net whose meshes appear identical with the endothelial pores. Domes and shelves formed of a fenestrated cytoplasmic sheet also occur above the ordinary level of the endothelial lining. A hypothesis implicating microvilli in partial renewal of the endothelial sheet is proposed. This study was assisted by Mr. K. Adachi of the SEM Laboratory at the Niigata University School of Medicine.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 175 (1977), S. 541-549 
    ISSN: 1432-0878
    Schlagwort(e): Blood vessels ; High voltage electron microscopy ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The luminal surface features and Junctional complexes from developing blood vessels in the rat central nervous system have been studied by high-voltage electron microscopy and scanning electron microscopy. Developing blood vessels exhibit three types of luminal projections; marginal folds or ridges at Junctional complexes, ridges not at Junctional complexes and microvilli. Both types of ridges are associated with troughs or depressions in the luminal surface of the endothelial cell. Those ridges not associated with Junctional complexes take part in the production of enclosed tunnels in the endothelial cell cytoplasm. Fusion of the external leaflets of Junctional complexes between adjacent endothelial cells occurred, initially, near the luminal surface of the blood vessel with other small fusion sites forming in the direction of the basal lamina secondarily. Further fusion activity to produce the zonula occludens type junction appeared to spread outwards from the smaller fusion sites.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 178 (1977), S. 17-38 
    ISSN: 1432-0878
    Schlagwort(e): Myosin ; Immunocytochemistry ; Adrenal medulla ; Exocytosis ; Secretion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Myosin was isolated in high purity from the bovine adrenal medulla by gel filtration and ion exchange chromatography. The purified myosin was analyzed by electrophoresis in gels containing SDS and found to contain a 200,000 molecular weight heavy chain and major light chains of molecular weights 20,000 and 17,000 in a 1∶1∶1 molar ratio. At high ionic strength the myosin had high Ca-ATPase and K-EDTA-ATPase activities and low Mg-ATPase activity. At low ionic strength, the Mg-ATPase was activated to a low level by rabbit muscle actin. The myosin was found to decorate F-actin in the absence, but not the presence of ATP. In low ionic strength solutions, the myosin assembled into characteristic bipolar filaments. The distribution of this myosin in the adrenal medulla and of cross-reacting myosin in several other bovine tissues was determined with the use of antimedullary myosin immunoglobulin G as a specific stain that was detected by direct and indirect immunofluorescence. In the medulla strong staining was seen between the chords of chromaffin cells indicating the presence of a highly muscular vasculature that may perform functions analogous to those of the myoepithelium of exocrine glands. The chromaffin cells showed weak positive staining around the nuclei and in a pattern radiating toward adjacent blood vessels. Cells of the inner zone of the adrenal cortex showed strong staining in the peripheral cytoplasm while cells in the intermediate and outer zones did not stain. In a blood smear, platelets and the cytoplasm of leukocytes stained strongly while erythrocytes did not stain. In striated muscle and the gray and white matter of the cerebrum only the capillaries and larger vessels stained. In the liver the phagocytic cells bordering vascular sinuses stained strongly while the hepatocytes were separated from one another by a 2 micron trilaminar band possibly representing the microfilament web surrounding the bile canaliculi and associated with junctional complexes. The results suggest that myosin is present in several highly differentiated, non-motile tissue cells where it may play a role in secretion or other specialized functions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 132 (1972), S. 333-364 
    ISSN: 1432-0878
    Schlagwort(e): Pituitary gland ; Amphibians ; Corticotrophs ; Ultrastructure ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé L'identification des cellules responsables de l'élaboration de la corticotropine (ACTH) a été envisagée chezRana esculenta. Les effects causés par l'interrénalectomie au niveau de l'hypophyse ont été étudiés parallèlement par immunofluorescence et au microscope électronique. Au microscope à fluorescence, les cellules détectées chez les animaux témoins avec un antisérum anti-synachten1 bordent en grand nombre les capillaires des zones médiorostrale et ventrale du lobe antérieur. Deux jours après interrénalectomie, le nombre de cellules fluorescentes décroît, douze jours après l'intervention, il ne subsiste pas d'éléments fluorescents dans cette zone. Au microscope électronique, les cellules corticotropes présentent de fines granulations d'environ 200 mμ de diamètre. Après interrénalectomie bilatérale, ces cellules sont fortement stimulées, elles sont sujettes à d'importantes modifications morphologiques; l'aspect morphologique des autres catégories de cellules antéhypophysaires, par contre, n'est pratiquement pas modifié. Douze jours après l'opération, la plupart de ces cellules sont dégranulées, l'ergastoplasme et l'appareil de Golgi sont bien développés. Ces observations suggèrent que les cellules péricapillaires de la moitié rostrale de lapars distalis sécrètent l'hormone corticotrope.
    Notizen: Summary Identification of the cell types responsible for the production of adrenocorticotropin (ACTH) was performed inRana esculenta. The effects of interrenalectomy on the pituitary cells were studied as well by immunofluorescence, as by electron microscopy. In control animals, the ACTH cells studied by immunofluorescence are numerous around the blood vessels of the medio-rostral and medio-ventral part of the anterior lobe. Two days after interrenalectomy the number of fluorescent cells decreases. Twelve days after, the operation all the fluorescent cells disappeared. The fine structure of the corticotrophs is characterized by the presence of small secretory granules (200 mμ). After bilateral interrenalectomy this cell type is markedly stimulated; it displays striking morphological changes, while the morphology of the other pituitary cell types is not considerably modified. Twelve days after operation most of these cells are degranulated, the rough endoplasmic reticulum and the Golgi apparatus are well developed. These findings suggest that the pericapillary cells of the rostral half of thepars distalis produce the adrenocorticotrophic hormone.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 136 (1973), S. 169-176 
    ISSN: 1432-0878
    Schlagwort(e): Cerebral ventricles ; Ependyma ; Sheep ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 200 (1979), S. 29-33 
    ISSN: 1432-0878
    Schlagwort(e): Magnocellular neurosecretory system ; Activation ; Rat ; Vasopressinergic neurons ; Oxytocinergic neurons ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The activated hypothalamic magnocellular neurosecretory system of the rat was studied in tissue sections, double stained with the unlabeled antibody peroxidase-antiperoxidase complex (PAP) technique. The results indicate that in animals with an activated hypothalamic magnocellular neuroendocrine system, as well as in normal animals, vasopressin and oxytocin are exclusively synthesized in separate vasopressinergic and oxytocinergic neurons.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 200 (1979), S. 409-423 
    ISSN: 1432-0878
    Schlagwort(e): Human placenta ; Classification of villi ; Histology ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The classification of human placental villi was reviewed on the basis of material prepared by means of special methods. The material from in situ normal-term placentae was biopsied by aspiration into glutaraldehyde. The classification was made on the basis of light-microscopic observations of semithin sections, reconstructions from serial sections, and scanning-electron micrographs. The peripheral villous tree is roughly divided into stem (ramuli), intermediate and terminal villi. The intermediate villi may be further subdivided as mature and immature types, which are found between the stem and terminal villi. Some of the terminal villi possess a local specialization described as the neck region. The histological characteristics and the branching pattern of each type are described, and the basis of the proposed classification is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 93
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 141 (1973), S. 235-253 
    ISSN: 1432-0878
    Schlagwort(e): Teleost yolk sac ; Pericardial sac ; Chloride cell ; Osmoregulation ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: 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.
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 94
    ISSN: 1432-0878
    Schlagwort(e): Pituitary ; Pars intermedia ; Adrenocorticotropin ; Melanocyte stimulating hormone ; Neural control over pars intermedia ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Electron microscopic localization of adrenocorticotropin (ACTH) and melanocyte stimulating hormone (MSH) in light, dark and ACTH cells in the pars intermedia (PI) of rats and mice is attempted by using antisera to βp 1–24, βp 17–39 ACTH and βb MSH with the immunoglobulin-peroxidase bridge technique. All of the PI parenchymatous cells (light, dark and ACTH cells), except the marginal cuboidal and the ependymal like cells, in rats and mice show very good localization of ACTH and MSH staining. In the light and dark cells, stain of varying intensity is seen on the secretory granules, vesicles and also in many places on the surface of the rough endoplasmic reticulum. There is no staining on the mitochondria, in the nuclei or in the granules inside and around the cisternae of the Golgi complex. Dark stained dense core granules become larger and larger as they appear farther and farther away from the Golgi complex. On the other hand, in the ACTH cells of the PI, ACTH antisera show stronger stained granules in the Golgi complex including the cisternae, similar to the pars distalis (PD) ACTH cells. From these observations it is concluded that the corticotropin in light and dark cells, is not packaged or condensed in the Golgi complex like that in the ACTH cells. MSH synthesis in light and dark cells also seems to be similar to that of ACTH synthesis. It is likely that the granules accumulate ACTH and MSH secretions after they are liberated from the Golgi cisternae, and thus become bigger and bigger in size. In case of ACTH cells of PI and PD, corticotropin may be packaged in Golgi cisternae and the size of the granule does not change much. This shows that there are distinct immunocytochemical differences between the light, dark and ACTH cells of the PI. At the moment, it is difficult to say whether ACTH and MSH are present in the same granule or not. The present and previous studies show that the ACTH and MSH secretion in the PI of rats and mice depends on the hypothalamic neural control.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 143 (1973), S. 451-463 
    ISSN: 1432-0878
    Schlagwort(e): Retina ; Pigment epithelium ; Photoreceptors ; Rana catesbiana ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 147 (1974), S. 163-167 
    ISSN: 1432-0878
    Schlagwort(e): Articular cartilage ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Samples of articular cartilage from four different human joints were obtained at surgery. Serial scanning electron micrographs taken at a magnification of 1000× were used to reconstruct an 0.25 mm2 area of articular surface. Within these given areas both normal and degenerated portions were seen. This study supports the concept that the surface morphology of articular cartilage varies from joint to joint and from area to area within a joint. This information should be useful for the interpretation of light and electron micrographs, as well as histochemical and biochemical data.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
    ISSN: 1432-0878
    Schlagwort(e): Ciliated cells ; Mucous membranes ; Trachea ; Heat exposure ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The mucociliary system of the respiratory tract is easily influenced by temperature — and humidity variations in the surrounding air. A series of functional in vitro experiments on heat-exposed rabbit trachea has been performed. The present investigation deals with the corresponding morphological changes of tracheal surface structures after exposure to temperatures between 40°C and 50°C and at a constant humidity of approximately 90 per cent. The following pathological findings were observed at a temperature of 42°C: 1. Fusion of cilia in their distal ends after 20–45 min., 2. appearance of submembranous vesicles without visible matrix after 45–165 min., 3. disappearance of vesicles and a definite deterioration of ciliary structures after 165 min.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 148 (1974), S. 27-44 
    ISSN: 1432-0878
    Schlagwort(e): Saccus vasculosus ; Rainbow trout ; Osmoregulation ; Infundibular recess ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Injection of a saccus vasculosus homogenate from sea water adapted rainbow trout into the third brain ventricle of fresh-water rainbow trout increased the survival time of the latter in sea water of high salinity. This indicated an active role of saccus vasculosus in osmoregulation. Autoradiographic analysis of brains from injected fish that had received a saccus vasculosus homogenate from sea water adapted specimens, in which the coronet cells of saccus vasculosus had previously been labelled with 3H-glucoseamine, revealed actual incorporation of labelled material into brain cells, especially in the hypothalamic region. The intracellular distribution of labelled material in the coronet cells of rainbow trout labelled with 3H-glucoseamine strongly indicates that such material represents a secretory product; it is therefore probable that the observed incorporation of label into brain cells of injected fish actually reflects normal processing of material secreted from the coronet cells. In the scanning electron microscope, the inside wall of the third brain ventricle of the rainbow trout was in many areas found to be covered with cilia. These apparently serve to keep liquor in circulation. The observation, both in injected and control animals, of free globules among these cilia supports the idea of an intra-ventricular transport of detached coronet cell material to the infundibular recess, as indicated by the autoradiographic analysis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 148 (1974), S. 111-125 
    ISSN: 1432-0878
    Schlagwort(e): Liver ; Sinusoids ; Kupffer cells ; Spaces of Disse ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The inner surface of sinusoids and adjacent hepatocytes have been examined by scanning electron microscopy. The endothelial cells lining the sinusoids show large numbers of fenestrations which vary greatly in size and arrangement. Some are very small (0.1 μm) and arranged in clusters; others that are much larger (∼1.0 μm) are subdivided by slender strands of cytoplasm. At sites where the larger fenestrae are present it is evident that the endothelial lining of the sinusoid is double. This may represent a kind of structural assurance against complete breakdown of what seems to be a very thin and fragile endothelial wall. Junctions between adjacent endothelial cells have not been found in these preparations. The open continuity of the sinusoid is occasionally interrupted by slender extensions of cells morphologically distinct from the thin fenestrated endothelial cells. These possess a characteristically textured surface and are thought to represent stellate Kupffer cells. The SEM images describe the subendothelial Spaces of Disse as being larger and as having more extensive ramifications than is generally evident from transmission micrographs. The space, limited on one side by the hepatocyte with numerous microvilli and on the other by endothelial cells, appears actually to be only part of an extensive labyrinth of intercellular channels. These connect the more discrete Spaces of Disse and extend into the narrower spaces between the hepatocytes. The total effect of this system is to expose the greater part of the liver cell surface to the blood filtrate. Microvilli populate the hepatocyte surfaces except for narrow margins which border the bile canaliculi. Whether their presence coincides with the adsorbing surfaces and their absence with secreting surfaces can be decided best by experimental studies.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 149 (1974), S. 301-312 
    ISSN: 1432-0878
    Schlagwort(e): Graafian follicle ; Ovulation ; Cytoplasmic granules ; Papilloma ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Changes of rabbit germinal epithelium at different times after an ovulatory dose of human chorionic gonadotrophin (HCG) were studied by scanning electron microscopy. Surface cells far from follicles did not show any consistent changes after HCG. However, germinal cells on growing follicles increased in size, while their microvilli successively decreased in length and number and eventually disappeared. At six hours after HCG, the cells over the apex showed protruding blebs and vesicles. Pour hours later the surface cells at the base had increased from about 7 to 12 μ in diameter and the contours of intracellular round structures were just visible. Half-way up to the apex the surface cells were still larger and contained several prominent intracellular round structures. At the apex the cells were collapsed and occasionally missing just before rupture. As regards the interpretation of these findings and their relation to the mechanism of ovulation, much remains to be done. However, since distinct and consistent changes characteristic of the later stages before rupture were found, the scanning electron microscope appears to be a valuable and convenient tool to evaluate the effect of different substances or procedures on the ovulatory process.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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