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  • 1977  (132)
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  • 101
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 179 (1977), S. 255-270 
    ISSN: 1432-0878
    Schlagwort(e): Chorion formation ; Viviparity ; Dermogenys pusillus ; Teleosts ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Eight stages in the oogenesis of Dermogenys pusillus were selected in order to demonstrate the formation of the egg membrane. In young oocytes (stages 1 and 2) the contact between oocyte and follicular cells is rather close. During stage 3 microvilli arise from the oocyte, and the follicular cells protrude lobopodia-like cell processes. When the microvilli have become arranged more regularly, the homogeneous material of the zona radiata externa is deposited between them (stage 4). During the subsequent stage (5) the inhomogeneous zona radiata interna appears. It attains its greatest thickness and its characteristic fine structure during stage 6. It then consists of cross-banded fibrillae and lamellae. Later on (stage 7) the egg membrane flattens, and finally it is a compact chorion consisting perhaps of very fine fibrils. Because of this development and of its complex fine structure the egg membrane of Dermogenys like that of Zoarces resembles that of oviparous teleosts but remains considerably thinner. The eight stages of oogenesis in Dermogenys are compared with those described by Arndt (1956) in several limnetic teleosts.
    Materialart: Digitale Medien
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  • 102
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 179 (1977), S. 517-530 
    ISSN: 1432-0878
    Schlagwort(e): Ribosomes ; Uterine epithelium ; Estradiol ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructural morphology of “free” cytoplasmic ribosomes of rat uterine epithelial cells was studied during diestrus, estrus, after ovariectomy, and after estradiol-17β administration to rats that were ovariectomized 1 to 25 weeks before hormone treatment. A change in size and contrast of ribosomes was observed concomitant with a transition from pre-existing monosomes to polysomes depending on the dose of estradiol and its route of application. In 3 weeks ovariectomized rats these changes in ribosomal granules take place at approximately the same time (30–45 min) when synthesis of “induced protein” was described biochemically. The morphological events after estradiol administration are discussed with respect to a primary site of estrogen action.
    Materialart: Digitale Medien
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  • 103
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 180 (1977), S. 453-465 
    ISSN: 1432-0878
    Schlagwort(e): Pancreas ; Fowl ; Innervation ; Synaptic vesicles ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The innervation of the pancreas of the domestic fowl was studied electron microscopically. The extrapancreatic nerve is composed mostly of unmyelinated nerve fibers with a smaller component of myelinated nerve fibers. The latter are not found in the parenchyma. The pancreas contains ganglion cells in the interlobular connective tissue. The unmyelinated nerve fibers branch off along blood vessels. Their synaptic terminals contact with the exocrine and endocrine tissues. The synaptic terminals can be divided into four types based on a combination of three kinds of synaptic vesicles. Type I synaptic terminals contain only small clear vesicles about 600 Å in diameter. Type II terminals are characterized by small clear and large dense core vesicles 1,000 Å in diameter. Type III terminals contain small clear vesicles and small dense core vesicles 500 Å in diameter. Type IV terminals are characterized by small and large dense core vesicles. The exocrine tissue receives a richer nervous supply than the endocrine tissue. Type II and IV terminals are distributed in the acinus, and they contact A and D cells of the islets. B cells and pancreatic ducts are supplied mainly by Type II terminals, the blood vessels by Type IV terminals.
    Materialart: Digitale Medien
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  • 104
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 181 (1977), S. 27-36 
    ISSN: 1432-0878
    Schlagwort(e): Central nervous system (Subfornical organ) ; Gap junctions ; Neuritic growth cones ; Ependyma ; Electron microscopy ; Freezeetching
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Intercellular contacts in the subfornical organ (SFO) of kittens 3, 16, and 29 days old were studied in thin sections and by the freeze-etch method. Gap junctions appeared between growing nerve processes and target cells. The junctions were interspersed between immature synapses lacking mitochondria as well as full preand postsynaptic membrane specializations. Gap junctions were seen on filopodia as well as on more mature processes. The morphology of these junctions was typical of those described earlier but they were of small size (0.2–0.3 μm). Gap junctions of peculiar form were also seen between ependymal elements in the SFO at 16 days. These were of large size (0.5–0.8 μm) and were often of segmented character. This segmentation consisted of bands 3–4 particles in width with a center-to-center spacing of 90 nm with particle free corridors between corresponding to the width of about two rows of particles. The margin of the group might be circumscribed by a row of particles. Although gap junctions of large size were seen between ependymal cells in thin section, features corresponding to the particle free corridors have not been observed to date.
    Materialart: Digitale Medien
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  • 105
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 181 (1977), S. 73-79 
    ISSN: 1432-0878
    Schlagwort(e): Muscles ; Neuromuscular junction ; T-system ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Sarcoplasmic tubules invaginating from the sarcolemma of the subneural region of muscle fibers are described in Atlantic hagfish and rat. In rat, the tubules invaginate from the bottoms of the secondary synaptic clefts. The density of tubule openings may be higher than the density of T-tubule openings elsewhere along muscle fibers.
    Materialart: Digitale Medien
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  • 106
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 181 (1977), S. 91-103 
    ISSN: 1432-0878
    Schlagwort(e): Granular cells ; Helix pomatia ; Electron microscopy ; Electrophoresis ; Secretion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Granular cells (cells crowded with colourless granules staining with paraldehyde fuchsin according to Gomori-Gabe and not containing calcium) are independent cells in the connective tissue of Helix pomatia. Histochemical data suggest that the granules are rich in sulfhydryl-containing proteins, but lack biogenic monoamines. Electron microscopic investigations confirm the supposed secretory activity of the granular cells. Secretory proteins are presumed to be synthetized in the endoplasmic reticulum and condensed in the Golgi apparatus giving rise to the granules. Extrusion occurs by exocytosis. Electrophoresis of homogenates, prepared from tissues containing numerous granular cells, results in the separation and identification of a secretory protein from the granular cells. An electrophoretically homologous protein is recognized in the hemolymph, but in very small quantities. Our findings and the work of others suggest the involvement of granular cells in neuroendocrine events.
    Materialart: Digitale Medien
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  • 107
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 181 (1977), S. 519-529 
    ISSN: 1432-0878
    Schlagwort(e): Rat prostate ; Copulation ; Secretion ; Cytochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effect of copulation on the rat coagulating gland (anterior prostate) was studied. At 4 to 6 h after the beginning of copulation the coagulating glands of rats that had produced copulatory plugs were nearly empty of secretion. Ultrastructurally, the coagulating gland has large cisternae of rough endoplasmic reticulum (RER) and few condensing vacuoles or secretion granules. After copulation the number of secretion granules and the frequency of their expulsion into the lumen increased. Also in the lumen were “fragmentation” vesicles (50–100 nm diameter) that were bounded by a unit membrane and appeared to arise from microvilli. At 4, 6, and 7h after the beginning of copulation there was an increase in apical blebbing. Blebbing was found in both perfusion and immersion-fixed tissue. Also, after copulation there was an increase in “light cells” that were characterized by reduced RER cisternae, an electron lucent cytoplasm, and atrophic Golgi apparatus. The luminal ground substance, secretion granules, and some Golgi elements, contained polysaccharides as seen with the periodic acid-thiocarbohydrazide-silver proteinate method.
    Materialart: Digitale Medien
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  • 108
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 178 (1977), S. 333-339 
    ISSN: 1432-0878
    Schlagwort(e): Thymus, Human fetus ; Lymphocytes ; DNA synthesis ; Autoradiography ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Fragments and suspensions of human fetal thymus were incubated in the presence of 3H-TdR to permit study of the distribution and morphology of DNA-synthesizing cells. Results of light and EM autoradiography showed that 1. although DNA-synthesizing cells were present in the medulla, the vast majority of these cells were localized in the thymic cortex, 2. cells with the typical EM appearance of small lymphocytes and lymphoid blast cells both synthesized DNA, and 3. cells in S-phase were predominantly 8 to 12 μm in size.
    Materialart: Digitale Medien
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  • 109
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 179 (1977), S. 367-375 
    ISSN: 1432-0878
    Schlagwort(e): Podocytes ; Tubifex tubifex ; Ultrafiltration ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The endothelia of Tubifex tubifex Müller consist of myoendothelial cells, chloragocytes, or podocytes. The latter seem to occur only as windows on the ventral vessel which has an endothelium of myoendothelial cells elsewhere. The podocytes are large cells, with several processes on the inner side which ramify into several pedicels. These are aligned upon the outside of the basement membrane which lines the inside of the endothelium. The gaps between adjacent pedicels are about 40 nm wide. In capillaries fenestrated endothelia occur with irregular spacings measuring up to 0.4–1 μm. A diaphragm in podocytes or capillary fenestrations do not seem to exist. The basement membrane is the only continuous layer lining the blood vessels and capillaries of Tubifex with a rather uniform diameter in the range of 50 nm. It is the only permeability barrier between blood and coelomic fluid.
    Materialart: Digitale Medien
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  • 110
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 179 (1977), S. 393-399 
    ISSN: 1432-0878
    Schlagwort(e): Myenteric plexus ; Mytilus edulis (Mollusca) ; 5,7-Dihydroxytryptamine ; 5-Hydroxytryptamine, dopamine ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Initial observations on the effects of 5,7-DHT on the myenteric plexus of Mytilus reveal extensive lesioning of monoamine nerves containing dense-cored vesicles. At least, two types of monoaminergic nerves could be recognized among the degenerating axons. The most affected were profiles with a predominance of large granular vesicles (56–200 nm) which resemble possible indoleamine nerves in the lamprey gut. The other type had small granular vesicles (40–56 nm) resembling catecholamine nerves of vertebrates. These two types of nerves possibly represent serotonergic and dopaminergic nerves, in accordance with pharmacological, biochemical and physiological evidence available in molluscs. There were, however, nerves with a population of medium-sized granular vesicles (56–130 nm) which were also damaged. Two other types of nerve profiles were unaffected by the drug. One conforms to cholinergic nerves while the other resembles ‘purinergic’ nerves in the vertebrate gut. These results confirm previous studies with dihydroxytryptamines on molluscan smooth muscle.
    Materialart: Digitale Medien
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  • 111
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 179 (1977), S. 413-427 
    ISSN: 1432-0878
    Schlagwort(e): Neuronal degeneration ; Non-neuronal elements ; Ventrobasal complex ; Immature CNS ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Sprague-Dawley albino rats ranging in age from neonate to 60 days postnatal (dpn) were subjected to cortical extirpations encompassing the SmI somato-sensory projection fields of neurons in the ventrobasal (VB) complex. Electron microscopy of this region reveals degenerative changes in VB neurons, the rate and severity of which is inversely proportional to the age of the animal (Matthews et al., 1977). Numerous, distinctive non-neuronal elements, similar to those infiltrating the perivascular space of some vessels in the area, rapidly accumulate within the zone of degeneration in animals lesioned between 0 and 9 dpn. These display dense, heterochromatin nuclei, concentrations of free ribosomes and rosettes, and pleomorphic dense bodies which become more evident as further reactive transformations accompany the phagocytic incorporation of degenerating neuronal remnants. Other non-neuronal elements exhibit a euchromatin nucleus, bundles of microtubules, and fewer free ribosomes. Such cells are also capable of phagocytosis and production of dense bodies. Both variants are comparable in appearance to the “M” cells of previous reports (Matthews and Kruger, 1973 b). Cortical lesions of older animals result in the appearance of “M” cells in VB; however, the population densities observed in the immature VB are not achieved. Conversely, astrocytic hypertrophy, associated with the increased incidence of degenerating boutons in the more mature animal, represents a prominent response to injury which does not occur to a significant extent in younger animals. Morphological criteria for determining the nature of some “M” cells are given for a discussion of their presumptive derivation from various mesodermal progenitors and a brief consideration of other hypothesized origins.
    Materialart: Digitale Medien
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  • 112
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 180 (1977), S. 283-292 
    ISSN: 1432-0878
    Schlagwort(e): Cardiac sarcomeres ; Euchaeta norvegica (Copepoda) ; T-tubules ; sarcoplasmic reticulum ; Couplings ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The membrane systems of the cardiac muscle cell of the copepod Euchaeta norvegica Boeck are described. The heart wall, which is between 0.12 and 1.36 μm thick, consists of an epicardium and a single layer of muscle cells. Invaginations of the sarcolemma forming transverse tubules have been found at all levels of the sarcomere with the exception of the H-band level. The longitudinal tubules of the same system are closely associated with the sarcoplasmic reticulum to form interior couplings at the A-I level of the sarcomere. Triadic couplings at the Z band level were not seen in E. norvegica, but peripheral couplings were demonstrated. Nexuses were found in the intercalated discs.
    Materialart: Digitale Medien
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  • 113
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 183 (1977), S. 403-417 
    ISSN: 1432-0878
    Schlagwort(e): Cerebral cortex ; Human foetus ; Synaptogenesis ; Cell culture ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Cells from foetal human cerebral cortex were mechanically dissociated and subsequently maintained in vitro for periods ranging between three and twenty-eight days. The ultrastructure of these cells at different stages of their development in culture was extensively examined. Nuclear and cytoplasmic features were extremely variable and a wide range of cell types was evidently represented. Of the three principal cell types found i.e. neurons, neuroglia and mesenchymal cells, only a minority of cells was classified with confidence, particularly during the first two weeks in culture. Extensive intercellular junctions of the adhaerens variety, common after 14 days in vitro were present at an earlier stage of development than synaptic profiles. First indications of synapse formation were observed after 21 days in vitro and after 24 days presynaptic sites filled with synaptic vesicles and with well defined presynaptic and postsynaptic thickenings were found. The significance of some of the features observed are both considered and discussed.
    Materialart: Digitale Medien
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  • 114
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 183 (1977), S. 445-455 
    ISSN: 1432-0878
    Schlagwort(e): Olfactory epithelium ; Goldfish ; Retrograde degeneration ; Olfactory receptor cell ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fine structure of the goldfish olfactory epithelium was studied by transmission and scanning electron microscopy. Six different cell types were distinguished. Identification of the olfactory receptor cell was accomplished by use of retrograde degeneration studies. Two morphologically distinct types of olfactory receptor cells were identified: one type bears radially oriented cilia (Type I cell); the other type bears microvilli (Type II cell). The other four cell types were not identifiable as olfactory receptor cells: they are ciliated cells (Type III), rod-shaped cells (Type IV), supporting cells (Type V), and basal cells (Type VI).
    Materialart: Digitale Medien
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  • 115
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 178 (1977), S. 495-515 
    ISSN: 1432-0878
    Schlagwort(e): Cerebral vessels ; Arterioles ; Myoendothelial tight junctions ; Innervation ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A total of 110 arterioles were examined in the brains of cats; different sites were studied including the cortex, putamen, pons and crus cerebri. No internal elastic laminae were seen in the subendothelial space, although occasional fragments of elastic material were present in the larger arterioles. The media was composed of one, two or three layers of smooth muscle cells which interlocked in such a way that the vessel wall thickness was constant. Numerous tight junctions were seen between adjacent smooth muscle cells and between the endothelium and smooth muscle cells. Apart from the usual cell organelles, the smooth muscle cells of arterioles had numerous dense patches on the cell surface. The structure of the adventitia varied according to the diameter of the vessel and the site in the brain; it contained adventitial cells, bundles of collagen fibres and nerve fibres. Innervation of arterioles was more constant in the brain stem than in the cortex. Metarterioles had less specialised, atypical smooth muscle cells, a discontinuous media and numerous, extensive myoendothelial tight junctions; they were not innervated by nerve fibres. The diameter of metarterioles was less than 10 μm whereas that of arterioles was 10–45 μm. The possible functional aspects of arteriolar innervation are discussed.
    Materialart: Digitale Medien
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  • 116
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 185 (1977), S. 1-16 
    ISSN: 1432-0878
    Schlagwort(e): Monocyte (Rat) ; Type of granules ; Peroxidase ; Catalase ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Rat blood monocytes contain granules of two types, primary and secondary granules, which can be distinguished on morphological grounds. Secondary granules have a halo between the limiting membrane and the matrix; primary granules have no halo and are generally more elongate than the secondary granules. In addition, there are differences in the distribution of the diameters of these two types of granules. The cytochemical characteristics of the peroxidatic activity of these granules were investigated by using different prefixation conditions in combination with a number of DAB media differing in pH and H2O2 concentration. Prolongation of the prefixation and increasing the pH of the incubation medium increased the staining intensity of the secondary granules and decreased the staining intensity of the primary granules. In unfixed cells peroxidatic activity could be demonstrated only in the primary granules. It is concluded from the present findings that peroxidase occurs in primary granules and not in secondary granules, whereas catalase is present in secondary granules but probably not in primary granules. No evidence was found for the presence of microperoxisomes in rat blood monocytes.
    Materialart: Digitale Medien
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  • 117
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 185 (1977), S. 69-76 
    ISSN: 1432-0878
    Schlagwort(e): Adrenal cortex, bovine ; Intramitochondrial bodies ; Electron microscopy ; Histochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Electron dense, homogeneous, mostly round intramitochondrial bodies were found in bovine adrenal glands, predominantly in the zona glomerulosa. The histochemical results obtained suggest that these bodies might contain a considerable amount of protein, although the possibility that substances other than proteins are contained in these bodies cannot be completely ruled out. The physiological significance of the intramitochondrial bodies remains unclear.
    Materialart: Digitale Medien
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  • 118
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 181 (1977), S. 81-90 
    ISSN: 1432-0878
    Schlagwort(e): Muscle ; Rotifers ; Myofilaments ; Supercontraction ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The Rotifer Trichocerca rattus has striated longitudinal retractor muscles. These muscles can be divided into two categories: 1. The central and ventral retractor muscles which, after fixation, are found in a supercontracted state: they probably contract very quickly. 2. The lateral retractor muscles which are in a relaxed state after fixation. However, if the animal is mechanically stimulated before fixation, these are also fixed in a contracted state: so, normally, these muscles probably contract more slowly than the first category. In the relaxed state, thin myofilaments of the lateral retractor muscles are folded at the I band level; this is a consequence of their compression provoked by the contraction of central and ventral retractor muscles. In muscles of the first type, the thick myofilaments are shorter (〈2 μ) than in the second type (2.5 μ).
    Materialart: Digitale Medien
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  • 119
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 183 (1977), S. 115-130 
    ISSN: 1432-0878
    Schlagwort(e): Lymph node ; Reticulum ; Connective tissue ; Ultrastructure ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A casting technique has been employed to display in three dimensions, the lymphatic microcirculation within the human lymph node. The casting compound filled the marginal sinus, and diffusely permeated the cortical lymphoid parenchyma. However, deep within the lymph node in the medullary region, the medium remained within the limits of the sinus walls. The casts showed well-defined channels appearing similar to vessels. These converged into larger vessels, which drained into efferent lymphatics leaving the node at the hilus. Electron microscopic examination showed that the outer wall of the marginal sinus and the trabecular side of trabecular sinuses had an intact, continuous endothelium with a basement membrane. However, gaps were present in the inner wall of the marginal sinus, as well as in the parenchymal wall of the trabecular sinus. In the medulla, the sinuses were lined by endothelial cells which appeared similar to macrophages. The sinus lining was incomplete and possessed numerous perforations. These observations indicated that sinus walls adjacent to connective tissue served as a barrier to cell movement, but those adjacent to a large lymphoid cell population had gaps, with cells in apparent transit between sinus lumen and parenchyma.
    Materialart: Digitale Medien
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  • 120
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 183 (1977), S. 303-318 
    ISSN: 1432-0878
    Schlagwort(e): Gastric mucous cells (Mouse) ; Differentiation ; Regeneration ; Neutron irradiation ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Mouse gastric mucosa was studied ultrastructurally and histochemically after exposure to fast neutron irradiation, the number of cells per gastric gland was decreased and the glands were shorter. At day 9, several glands showed a dilated lumen lined by flattened cells. Between days 9 and 16, some of the glands disappeared. Parietal and chief cells disappeared from the remaining glands. At the same time, restoration of the mucosa started. At day 6, proliferative cells were scattered along the isthmus. As in controls, the isthmus contained a few undifferentiated cells many differentiating surface mucous cells (SMC) with developing rough endoplasmic reticulum and silver proteinate-reactive Golgi elements and small secretory granules. At day 9, numerous proliferative cells were clustered in foci. Almost all these cells contained silver proteinate-reactive Golgi elements, granules and vesicles. Most of them were SMC, others mucous neck cells (MNC) or intermediates. At day 16, proliferative foci were larger and consisted of differentiated mucous cells. Regenerated foveolae and glands constisted of large SMC and MNC and a few fibrillovesicular cells. In conclusion, proliferative activity is confined to undifferentiated cells and differentiating mucous cells, which identifies them as the progenitors of the other gastric cell types.
    Materialart: Digitale Medien
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  • 121
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 177 (1977), S. 523-538 
    ISSN: 1432-0878
    Schlagwort(e): Cat kidney ; Lipids ; Cholesterol ; Reabsorption ; Histochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Lipid deposits in the cat kidney are mainly located in the epithelium of the proximal tubuli contorti, particularly in the pars contorta. As the amount of fatty acids in the blood of renal arteries is higher than in renal veins, the lipid inclusions are likely to be formed in the proximal convoluted tubule. Whether fat occurring in the urine has been released from the nephron epithelium and the mode of this release remains obscure. The structural equivalent of lipid extrusion into the tubules has not been observed. Components of the tubular lipids include triglycerides, phosphoglycerides and cholesterol. The results of the digitonin-cholesterol reaction favour the assumption that cholesterol is eliminated in the glomeruli and pinocytotically reabsorbed by the brush border cells, this process possibly serving recycling of this compound. The dilated basal labyrinth and intercellular space contain perpendicularly oriented lipid accumulations that reach the basal lamina. The ultrastructure of the lipid storing cells of pars contorta reacting positively for phosphoglyceride and cholesterol is characterised mainly by bodies with marginal plates. As far as can be judged from their morphology, these bodies are interpreted as large peroxisomes. A special feature of the pars recta are dumbbell shaped bodies and elongated or cup-like mitochondria concentrically surrounding cytoplasmic areas, as well as a well-developed smooth ER. In what way the organelles of the brush border cells are involved in catabolic and anabolic processes as far as renal lipid metabolism is concerned remains to be answered.
    Materialart: Digitale Medien
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  • 122
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 178 (1977), S. 83-96 
    ISSN: 1432-0878
    Schlagwort(e): Interpeduncular nucleus (ITP) ; Electron microscopy ; Secretory granules ; Interpeduncular cistern
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Special types of cells of the interpeduncular nucleus (ITP) in the frog, Rana esculenta, are described after three types of fixation: osmium tetroxide, aldehydes and potassium permanganate. Large granules with a sub-unit structure occurring together with bundles of filaments and elongated mitochondria are illustrated in the processes of cells, the perikarya of which lie distant from the ependymal lining of the aqueduct of Sylvius. Such processes cross the ITP in a dorso-ventral direction perpendicular to the fibers which traverse the nucleus in a horizontal and frontal plane. They reach the subpial ventral surface of the nucleus ending in foot-like expansions where granules and mitochondria are assembled. The secretory nature of the granules is assumed. The release of possible peptide hormones into the interpeduncular cistern, where a pool of cerebrospinal fluid and large blood vessels occur, cannot be excluded.
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  • 123
    Digitale Medien
    Digitale Medien
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    Cell & tissue research 178 (1977), S. 97-101 
    ISSN: 1432-0878
    Schlagwort(e): Midgut ; Insect ; Endoplasmic reticulum ; Transport ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Lamellar stacks of cisternae regularly spaced and bound to each other by fine filaments are observed in the apex of midgut cells of Aeshna cyanea. These cisternae are connected with the rough endoplasmic reticulum but are devoid of ribosomes except on their terminal sacs. Their location and their structure, quite different in fed and starved animals, suggest that they are involved in intracellular transport.
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  • 124
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 178 (1977), S. 129-141 
    ISSN: 1432-0878
    Schlagwort(e): Choroid plexus ; Vasopressin ; Neurosecretion ; Rat ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Light and electron microscopic examination of choroid plexuses from lateral ventricles of water-deprived and subcutaneously or intravenously vasopressin administered rats reveal morphologic changes typical for vasopressin responsive fluid transporting epithelia during hormonal stimulation. Ultrastructural changes noted in both dehydrated and vasopressin treated animals included: the frequent occurrence of choroidal “dark” cells, dilatation of the lateral and basal intercellular spaces, increased vacuolization of the apical cytoplasm, and a change in microvillar conformation from the normal clavate type to those with a filiform shape. On the basis of the ultrastructural changes observed it is proposed that the choroid plexus be regarded as a target tissue for vasopressin. These findings indicated that a vasopressinmediated transchoroidal cerebrospinal fluid absorption capability exists.
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  • 125
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 183 (1977), S. 471-489 
    ISSN: 1432-0878
    Schlagwort(e): Spleen ; Germfree mice ; Lymphocyte ; Plasma cell ; Microenvironment ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The cellular events during the primary immune response in T and B cell compartments in the splenic white pulp were analysed in germfree mice immunized with sheep erythrocytes. Light, fluorescence and electronmicroscopic studies revealed that the initial formation of lymphoid blast cells occurs in the thymus-dependent area, i.e. the central periarteriolar lymphatic sheath (central PALS), 2 days after immunization. Lymphoblasts were found in close relation with erythrocyte-containing macrophages and with interdigitating cells. With fluorescence microscopy these blast cells were Ig negative. Lymphoblasts in the central PALS showed many polyribosomes in the cytoplasm, but were virtually devoid of endoplasmic reticulum. The ultrastructure of lymphoblasts in the central PALS, and their relation with interdigitating cells, suggests that these cells are the progeny of antigen-activated T cells. Cells with a positive cytoplasmic fluorescence, plasmablasts, appeared 3 days after immunization in the peripheral part of the PALS. During the progress of the immune response these cells accumulated around branches of the central arteriole, and moved along marginal zone bridging channels towards the red pulp. In the electron microscope plasmablasts showed many polyribosomes, short strands of rough endoplasmic reticulum close to mitochondria, and a few electron-dense bodies. The cell organelles of plasmablasts were frequently gathered in a so called “uropod”, which is a morphological sign of active cell movement. Germinal center formation started within primary follicles, 4 days after immunization. Blast cells in germinal centers did not show cytoplasmic fluorescence. During the course of the immune response, germinal centers extended in diameter, and fluorescent dendritic cells appeared at the periphery of the germinal center. From the present observations we conclude that: (1) cellular cooperation between different lymphoid and non-lymphoid cell types during the immune response against SRBC takes place in the PALS, (2) the cellular cooperation in the PALS results in the differentiation of B cells into immunoglobulin-producing plasmablasts, (3) the cellular cooperation in the PALS preceeds the formation of germinal centers in primary follicles, hence germinal centers are not involved in early T-B cell cooperation.
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  • 126
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 185 (1977), S. 191-197 
    ISSN: 1432-0878
    Schlagwort(e): Lateral line organs ; Ambystoma maculatum ; Neurotrophic activity ; Aneurogenic development ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An ultrastructural study was performed to determine the ability of presumptive lateral line tissue in A. maculatum embryos to migrate and differentiate in the absence of all sensory innervation. In experimental animals, all presumptive neural tissue was surgically removed at Harrison's stage 24, leaving only the posterior portion of the post-auditory placode. At later stages, completely differentiated aneural lateral line organs were found in the midbody region of the larvae. These were morphologically similar to those of control larvae. No signs of atrophy or degeneration of the neurqmasts were seen even after several weeks of nerve-free conditions.
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  • 127
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 185 (1977), S. 231-237 
    ISSN: 1432-0878
    Schlagwort(e): Brown adipose cells ; Mitochondria ; Hibernation cycle ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The mitochondrial structure in the brown adipose cells of the golden mantled squirrel, Citellus lateralis, was examined throughout the year in biopsy samples. The mitochondria showed remarkable and apparently reversible changes in size and internal structure related to the physiologic activity of the animal. In the active animal the size of the largest mitochondria was 2.4 μm × 1.5 μm; during hibernation it increased to 7 μm × 2.5 μm; and during arousal it reached 11.2μm × 5.3 μm. The cristae of the mitochondria in the brown adipose cells of the animals in hibernation phase formed loops, whorls and mesh-like interconnections. During the arousal phase they underwent further configurational changes. The most remarkable structure was associated with mitochondria of most unusual proportions which by dissolution gave rise to a new generation. This was a common finding during arousal but did not occur in any other phase of the hibernation cycle. The new mitochondria were virtually indistinguishable from those of brown adipose cells of any active animal.
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  • 128
    Digitale Medien
    Digitale Medien
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    Cell & tissue research 185 (1977), S. 239-246 
    ISSN: 1432-0878
    Schlagwort(e): Pancreatic polypeptide ; Endocrine human pancreas ; Histochemistry ; Immunohistochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The consecutive semithin — thin section method was employed to identify pancreatic-polypeptide-containing cells in the human pancreas. The immunocytochemical staining of semithin sections with the peroxidase-antiperoxidase complex allowed a precise ultrastructural description of the immunoreactive cells on the adjacent thin section. Two populations of small granulated cells could be distinguished with this technique: one group is formed by cells whose secretory granules with a mean diameter of 141 nm show specific immunoperoxidase staining with anti-PP serum, while the other group consists of cells whose secretory granules measuring 118 nm in diameter show no immunoreactivity to anti-PP serum. The former cells which will be designated as PP-cells, are not identical with the D1-cells of the revised Wiesbaden classification of endocrine cells.
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  • 129
    Digitale Medien
    Digitale Medien
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    Cell & tissue research 185 (1977), S. 351-360 
    ISSN: 1432-0878
    Schlagwort(e): Nerve cord ; Oligochaeta ; Aminergic neurons ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The aminergic nature of the CV neurons present in the genital segments of the nerve cord of Eisenia foetida is demonstrated by fluorescence microscopy and by the chromaffin reaction modified for electron microscopy.
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  • 130
    Digitale Medien
    Digitale Medien
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    Cell & tissue research 179 (1977), S. 467-473 
    ISSN: 1432-0878
    Schlagwort(e): Neurophysin ; Supraoptic nucleus ; Neurosecretory granules ; Electron microscopy ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Localization of neurophysin in neurons of the supraoptic nucleus was accomplished using an unlabeled-antibody, post-embedding, immunoperoxidase technique. Neurophysin was exclusively associated with neurosecretory granules within cell bodies of supraoptic neurons and their processes.
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  • 131
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 179 (1977), S. 531-562 
    ISSN: 1432-0878
    Schlagwort(e): Ribosomes ; Polyribosomes ; Messenger RNA ; Protein synthesis ; Cytoplasmic filaments ; Cytoplasmic RNP-network ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructural morphology of ribosomes was studied in tissue sections of rat uterus using different fixatives (acrolein, formaldehyde, acetic acid, methanol-acetic acid, OsO4) after various pre-incubations in solutions of different osmolarity, electrolyte content, and pH. In addition, whole-mount ribosomes of spread cytoplasm of epithelial cells were examined. The results indicate: Ribosomes are “thickenings” in the course of a cytoplasmic RNP-network which extends in three dimensions between nucleus and plasma membranes. This network consists of fibrils which vary in width depending on intrinsic and extrinsic factors. Often the fibril width is approx. 100 Å. In places where the fibril is folded up into ribosomal “granules” and strands the width may be 300 Å. Each fibril seems to be composed of two elementary filaments, 10 Å up to 40 Å thick. Estimation of filament length within a ribosomal “granule” allowed the conclusion that only a fraction of a 45 S-RNA filament is folded up into a “ribosome” in cytological preparations. No morphological evidence was found for clefts within ribosomes or single messenger RNA filaments “piercing” ribosomes. Filaments of membrane-bound ribosomes apparently show continuities with fibrils within the cytoplasmic matrix on the one side and with filaments within the cisternae of the endoplasmic reticulum on the other. Ribosomal filaments of stromal cells also seem to have filamentous continuities with extracellular fibrils. This morphological evidence opens new perspectives concerning the role of RNA filaments in protein synthesis. Part of this work was continued during a fellowship 1974/75 at the Laboratory of Human Reproduction and Reproductive Biology, Dept. of Anatomy, Harvard Medical School, Boston supported by the Ford Foundation. The author thanks Dr. D.W. Fawcett for making this fellowship available. This study was supported by the Deutsche Forschungsgemeinschaft
    Materialart: Digitale Medien
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  • 132
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 184 (1977), S. 225-236 
    ISSN: 1432-0878
    Schlagwort(e): Human spleen ; Splenic innervation ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The innervation of four normal human spleens was investigated by electron microscopy. Unmyelinated nerve fibers accompanied the arterial vascular system up to the arterioles of the red pulp. Neither myelinated nerve fibers nor ganglion cells were seen in the splenic hilum or in the splenic tissue itself. The nerve fibers terminated against the smooth muscle cells of the blood vessels in a manner that is typical of the autonomic nervous system. The terminal axons contained small and large granular vesicles and thus were adrenergic nerve fibers. In contrast to the results of previous studies using silver impregnation methods innervation of the red or white pulp could not be demonstrated. The findings on human spleens agree with those on mammalian spleens obtained by other authors using ultrastructural and fluorescence histochemical methods.
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  • 133
    Digitale Medien
    Digitale Medien
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    Research in experimental medicine 168 (1976), S. 219-227 
    ISSN: 1433-8580
    Schlagwort(e): Initial phase of neurogenic pulmonary edema ; Perfusion fixation ; HRP ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The initial phase of pulmonary edema development following intracranial pressure elevation was studied by means of transmission electron microscopy. Using perfusion fixation and application of a blood tracer (HRP horseradish peroxidase) the time sequence and site of fluid leakage out of pulmonary vessels was demonstrated: - passage of edema fluid through intercellular clefts of alveolar capillary endothelium - edema accumulation in alveolar interstitial tissue - draining of edema fluid from the alveolar septum to the interstitium of terminal bronchioli and to lymphatic vessels. An early interepithelial fluid leakage out of the alveolar wall remains questionable.
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  • 134
    Digitale Medien
    Digitale Medien
    Springer
    Archives of gynecology and obstetrics 220 (1976), S. 199-208 
    ISSN: 1432-0711
    Schlagwort(e): Rat ovaries ; Diabetes mellitus ; Alloxan ; ATP/ADP ; Lactate/pyruvate ; NADP/NADPH ; Glucose ; Protein content ; Hydrogen-coveying enzymes ; alkal. phosphatase ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Es wurde der Einfluß eines alloxan-induzierten Diabetes mellitus auf den Stoffwechsel und die Ultrastruktur juveniler Rattenovarien untersucht. Der Diabetes mellitus bewirkte folgende Änderungen imStoffwechsel: Abfall der Konzentration von ATP und NADPH, Anstieg des Lactat/Pyruvat-Quotienten über 40, Abfall des ATP/ADP-Quotienten unter 1, Aktivitätsminderung der wasserstoffübertragenden Enzyme G-6-DH, Isocitrat-DH, Malat-DH, Aktivitätszunahme der alkalischen Phosphatase, Erniedrigung des Proteingehaltes.Ultrastruktur: Nahezu vollständiges Verschwinden des rauhen endoplasmatischen Reticulums, Schrumpfung der Mitochondrien, Reduktion der cristae und Kondensation der Matrix. Das glatte endoplasmatische Reticulum bleibt unverändert, der Golgi-Komplex ist in seiner Ausdehnung reduziert. Leichte Extrahierbarkeit der Lipiddepots. Die Befunde sprechen für eine Hemmung der oxydativen Phosphorylierung sowie für eine Beeinträchtigung des Steroid- und Proteinstoffwechsels.
    Notizen: Summary Tests were carried out on the influence of alloxan-induced diabetes mellitus on the metabolism and the ultrastructure of ovaries of juvenile rats. The diabetes mellitus caused the following changes in themetabolism: reduction in the concentration of ATP and NADPH, increase in the lactate/pyruvate quotient to above 40, reduction in the ATP/ADP quotient to below 1, reduction in the level of activity of the hydrogen-conveying enzymes G-6-P-dehydrogenase, isocitrate dehydrogenase and malate dehydrogenase, increase in the level of activity of the alkaline phosphatase, reduction of the protein content. Ultrastructure almost complete disappearance of the rough endoplasmic reticulum, shrinkage of the mitochondria, reduction of the cristae and condensation of the matrix. The smooth endoplasmic reticulum remains unchanged, the extent of the Golgi-complex is reduced. Easy removal of the lipid deposits.
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  • 135
    Digitale Medien
    Digitale Medien
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    Archives of gynecology and obstetrics 221 (1976), S. 277-287 
    ISSN: 1432-0711
    Schlagwort(e): Electron microscopy ; Endocrinology ; Pathology ; Testicular feminization ; Testis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Testicular tissue was investigated by electron microscopy in a case of testicular feminization. The seminiferous tubules were lined by spermatogonia and by Sertoli cells. Spermatocytic maturation was not observed. Leydig cells were numerous and contained well developed, abundant vesicular smooth-surfaced endoplasmic reticulum and large mitochondria with tubulovesicular cristae. Reinke crystalloids were absent. The ultrastructural findings were consistent with the assumption that Leydig cells were under adequate stimulation and were in a stage of active secretion. Hence, the results seem to indicate that testicular endocrine function was maintained in the studied case.
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  • 136
    ISSN: 1432-1106
    Schlagwort(e): Rolando substance ; Degeneration ; Atrophy ; Axotomy ; Histochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Disappearence of fluorid-resistant acid phosphatase activity from the ipsilateral Rolando substance after transection of the peripheral nerve, is shown to be due to the cessation of enzyme supply from dorsal root ganglion cells to their central terminals. This is accompanied by (or ensues in consequence of) a fine structural derangement of these terminals (“degenerative atrophy”). Fine structural alterations of axon terminals undergoing degenerative atrophy, though similar to some extent to those seen during early phases of a Wallerian degeneration, are markedly different. Also myelinated nerve fibers, both in the dorsal horn and in dorsal columns, are affected by degenerative atrophy. This important, new trophical feature of sensory ganglion cells suggests a delicate metabolic balance between peripheral and central axonal branches of bipolar (pseudounipolar) cells. Degenerative atrophy raises serious implications in evaluating hodological experiments based upon Wallerian degeneration and offers new perspectives for theoretical and clinical neurology.
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  • 137
    Digitale Medien
    Digitale Medien
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    Virchows Archiv 369 (1976), S. 181-190 
    ISSN: 1432-2307
    Schlagwort(e): Cerebral hemorrhage ; Cerebral artery disease ; Plasmatic arterionecrosis ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An electron microscopic study of the intracerebral arteries from 9 hypertensive cases was performed in order to elucidate the morphogenesis of the plasmatic arterionecrosis which was considered to be the direct cause of hypertensive intracerebral hemorrhage. In the preceding stage of the arterial lesions, marked necrosis of medial smooth muscle cells and increase of basement membrane-like substance in the intima and media were observed. The lumina of these arteries were slightly dilated. The dilatation and hemodynamic factors were supposed to cause endothelial injury resulting in blood plasma insudation into the intima through the opened spaces between endothelial cells. The insudated blood plasma dispersed and dissolved the basement membrane-like substance, collagen and elastic fibers in the arterial wall, leading to the development of the plasmatic arterionecrosis.
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  • 138
    Digitale Medien
    Digitale Medien
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    Virchows Archiv 371 (1976), S. 251-263 
    ISSN: 1432-2307
    Schlagwort(e): Human liver ; Electron microscopy ; Stereology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The stereologioal model and the base-line data of normal human liver needle biopsy-specimens are presented. Four reference systems were introduced: 1 cm3 of liver tissue, 1 cm3 of hepatoeyte, 1 cm3 of hepatocytic cytoplasm and the volume of an average “mononuclear” hepatocyte. The sampling was done at three levels of magnification (1,000 ×, 5,000 × and 10,000 ×). A lobular differentiation was not considered. The baseline data show strikingly small variations (s.e. less than 10%) within the individual biopsy specimen and within the group of four biopsies. There is no principal difference between human beings presented here, rats, mice and dogs. Only the mean individual volume of human hepatocytes is clearly larger than in rodents. The problems and limitations of stereological work on liver biopsy specimens are discussed.
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  • 139
    Digitale Medien
    Digitale Medien
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    Virchows Archiv 370 (1976), S. 273-289 
    ISSN: 1432-2307
    Schlagwort(e): Bone marrow biopsy ; Hairy cell leukemia ; Differential diagnosis ; Myelofibrosis ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In 24 patients with hairy cell leukemia, histological and fine structural findings from biopsies of the bone marrow are reported and their validity is compared with other diagnostic procedures available. Diagnosis by light microscopy of anterior iliac crest biopsies obtained by the method of myelotomy is possible with a high degree of accuracy. The differentiation of hairy cell leukemia from other myelo- or lymphoproliferative disorders based on cytomorphology as well as patterns of growth is emphasized. Morphological differences between fibrosis in this entity and other lesions such as malignant lymphomas, Hodgkin's disease, osteomyelofibrosis and -sclerosis are emphasized. Electron microscopy of the bone marrow shows single fibroblastic cells with numerous slender cytoplasmic processes randomly dispersed among the hairy cells. These fibroblasts are probably responsible for the synthesis of the reticulin and collagen fibres in their surroundings. Moreover fine structure of the hairy cells demonstrates pinocytic activity but no apparent phagocytosis in contrast to the phagocytic reticulum cells (histiocytes, macrophages). In the bone marrow the precursor cells and the many immature forms of hairy cells exhibit an overall lymphocytoid appearance during their maturation, suggesting a lymphocytic origin.
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  • 140
    Digitale Medien
    Digitale Medien
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    Virchows Archiv 370 (1976), S. 141-150 
    ISSN: 1432-2307
    Schlagwort(e): Angiotensin ; Catecholamine ; Strophanthin ; Rat heart ; Myocardial necroses ; Optical microscopy ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei der Ratte nehmen die durch Angiotensin induzierten Herzmuskelfasernekrosen (75 mg/kg s.c. und i.p.) unter Strophanthin-Praemedikation (2 × 10−2 mg/kg i.p.) an Zahl und Ausmaß ab. Darüberhinaus ändert sich der elektronenmikroskopische Befund: Die alleinige Gabe von Angiotensin bewirkt eine Vakuolisation der Mitochondrion und eine Dilatation des endoplasmatischen Reticulum ohne Alteration der Myofibrillen. Die kombinierte Gabe von Strophanthin und Angiotensin führt zu einer primären Zerstörung der Myofibrillen, ohne daß Mitochondrien und tubuläres System sichtbar verändert werden. Der Schutzmechanismus des Strophanthin wird im Sinne einer Ökonomisierung des Zellstoffwechsels bei relativer coronarieller Insuffizienz diskutiert, welche durch die starke vasokonstriktorische Wirkung des Angiotensin ausgelöst wird.
    Notizen: Summary Number and degree of angiotensin-induced heart muscle necroses in the rat (75 mg/kg body weight) are diminuished by premedication with strophanthin (2 × 10−2 mg/kg body weight). The electron-microscopic findings are also changed: the application of angiotensin only results in vacuolization of mitochondria and a dilatation of the endoplasmatic reticulum while myofibrils are unaltered. Angiotensin in combination with strophanthin has a direct destructive effect on the myofibrils without evident changes of the mitochondria and the tubular system of the heart. The protective action of Strophanthin on the heart muscle cell is discussed in the sense of an economization of the cellular metabolism under conditions of relative coronary insufficiency, induced by the vasoconstructive effect of angiotensin.
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  • 141
    ISSN: 1573-0832
    Schlagwort(e): Trichophyton mentagrophytes ; Thiocyanatopyrazole derivatives ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Four thiocyanatopyrazole derivatives were synthesized and their fungistatic activity was demonstrated in vitro against a number of dermatophytic fungi. In Trichophyton mentagrophytes, the most active compound induced an unusual increase of the plasma membrane with production of intra and extracytoplasmic complexes, a deterioration of nuclear and mitochondrial membranes and a formation of autophagic-like vacuoles. Plasmolysis, accompanied by an almost complete disorganization of cytoplasmic structures, seemed to be the final event. A possible mechanism of action of the compounds was discussed.
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  • 142
    Digitale Medien
    Digitale Medien
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    Anatomy and embryology 149 (1976), S. 123-148 
    ISSN: 1432-0568
    Schlagwort(e): Rat-placenta ; Gap junctions ; Electron microscopy ; Freeze-fracturing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The placental labyrinth of the chorioallantoic placenta of the rat was studied with transmission and scanning electron microscopy. Full-term placentas were investigated after perfusion fixation from the maternal and fetal circulation, including thin-sectioning and freeze-fracturing. The labyrinthal three-dimensional structure was found not to be trabecular but spongious lamellar. We propose a division of the lamellae into three groups—the first, second, and third order. The trophoblastic layers are described in detail, showing a cellular layer I and two syncytial layers II and III. Layer I is found to be fenestrated and highly permeable. Layers II and III are connected by extended gap junction areas. It is suggested that the gap junctions function as a molecular sieve and represent the limiting barrier in diaplacental transport of the choriollantoic placenta. Fetal capillaries are fenestrated and endothelial cells are connected by tight junctions. The functional significance of the morphologic findings is discussed.
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  • 143
    Digitale Medien
    Digitale Medien
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    Acta neuropathologica 34 (1976), S. 183-197 
    ISSN: 1432-0533
    Schlagwort(e): Lewy body ; Electron microscopy ; Parkinsonism ; Dense core vesicles ; Catecholamines ; Mitochondrial inclusions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The Lewy body, a characteristic nerve cell inclusion in idiopathic parkinsonism, was examined by electron microscopy in the stellate ganglion, obtained from 9 patients at autopsy. Three main forms of Lewy bodies or Lewy body-related structures were demonstrated: A. Rare filamentous Lewy bodies, similar to Lewy bodies in the central nervous system. B. Granular Lewy bodies in nerve cell processes. C. Abnormal nerve cell processes, filled with heterogenous material. Large dense core vesicles were prominent in the last 2 forms. None of these abnormalities were found in 2 control groups consisting of 9 parkinsonism cases without central nervous system Lewy bodies, and 17 cases without parkinsonism. The filamentous Lewy body (type A) was found in the perikaryon and was surrounded by neuromelanin, whereas the other forms (type B and C) were seen in nerve cell processes. Mitochondrial inclusions, present mainly, but not exclusively, in neuromelanin-containing cells, were not related to Lewy body formation or to parkinsonism.
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  • 144
    Digitale Medien
    Digitale Medien
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    Acta neuropathologica 34 (1976), S. 207-218 
    ISSN: 1432-0533
    Schlagwort(e): Immunomyopathy ; Muscle disease ; Electron microscopy ; Experimental muscle pathology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An experimental model of the autoimmune process was developed to study the ultrastructural aspects of immunomyopathies. Every type of muscle fibre organelle was affected and the severity of injury increased in direct proportion to time following immunization. It is suggested that ultrastructural methods are useful in studies concerned with the analysis of structural aspects of experimental immunomyopathies.
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  • 145
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 13-25 
    ISSN: 1432-0533
    Schlagwort(e): Chordoma ; Tissue and organ culture ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Explants of a human sacral chordoma were successfully maintained on collagen-coated coverslips, gelfoam sponge matrices, and Millipore filter platforms for up to 30 days. Tumor cells cultured on collagen-coated coverslips became increasingly vacuolated whereas those maintained in organ culture were entirely free of vacuoles after 22 days in vitro. A single basic tumor cell, small and polygonal with a large central spherical nucleus and abundant endoplasmic reticulum and Golgi apparatus, was recognized. Vacuoles were formed as the result of the progressive expansion of smooth endoplasmic reticulum. Coalescence of these vacuoles produced the physaliferous cell of light microscopy.
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  • 146
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 139-150 
    ISSN: 1432-0533
    Schlagwort(e): Electron microscopy ; Olfactory esthesioneurocytoma ; Neurosecretory granules ; Microtubules ; Dystrophic axons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary One case of malignant tumour of the left nasal cavity is reported in a woman 56 year old, affected by the disease 24 years. Numerous recurrences appeared and various histological diagnoses were performed. At the last surgery, the tumour invaded the ethmoïd and was a typical olfactory esthesio-neurocytoma. By electron microscopy, mature ganglion cells with dense cored vesicles (neurosecretory granules) were densely packed. Neuritic processes with microtubules were rarely normal in size and their content was most often abnormal; furthermore dystrophic axons were noted in great number.
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  • 147
    ISSN: 1432-0533
    Schlagwort(e): Neurinoma ; ENU ; Prenatal carcinogenesis ; Transplantability ; Metastases ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary With a single dose of 80 mg/kg ENU, a tumour originating from the trigeminal nerve was induced transplacentally in the offspring of a Sprague-Dawley rat. The neoplasm diagnosed as a neurinoma, was transplanted over 20 passages to 5 six-month-old Sprague-Dawley rats in each case. During this time, the biological behaviour of the tumour as well as its histological appearance were followed. Ultrastructural observations were made of the 20th passage. The tumour caused multiple metastases in the lung and in the lymph nodes of the neck in 30 animals. Recurrences were formed within a week, metastases of the lung appeared from then on in all cases. During the time of transplantation, the neurinoma dedifferentiated histologically so markedly that it was no longer possible to classify the neoplasm as a neurogenous tumour after 20 passages. Ultrastructurally, poorly differentiated Schwann cells could nervetheless be recognized.
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  • 148
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 295-305 
    ISSN: 1432-0533
    Schlagwort(e): PKU bodies ; Demyelination ; Dysmyelination ; Neuroglia ; Inborn errors of metabolism ; Phenylketonuria ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of various inclusions within oligodendroglial cells in the brains from two phenylketonuric patients was studied. Characteristic lamellar, oval, slightly irregular inclusions measured between 0.5 and 2 micra in diameter and were bounded by a single membrane. The longitudinal and transverse lamellae of these inclusions had a distinct pattern. In analogy to lamellated but different inclusions of other diseases, these structures were termed “PKU bodies”. Various possibilities that would explain the morphogenesis of the PKU bodies and other inclusions in the oligodendroglial cells, and the significance of these findings, are discussed.
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  • 149
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 369-379 
    ISSN: 1432-0533
    Schlagwort(e): Leukodystrophy, metachromatic ; Prenatal diagnosis ; Sulphatide accumulation ; Myelination, central, peripheral ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Light and electronmicroscopic findings are reported in a case of metachromatic leukodystrophy diagnosed prenatally who died after iatrogenic abortion during the 23th week of gestation. The brain of this foetus was not yet myelinated while the spinal cord showed early, and the peripheral nerves advanced myelination. The onset and the degree of myelination were similar as in a normal foetus of the same age. Ultrastructurally there was evidence of sulphatide storage before the beginning of myelination. During myelination lysosomal storage material, staining metachromatically in acid cresyl violet preparations, appeared in oligodendrocytes and Schwann cells. Besides sulphatide storage material, prominent amounts of neutral lipids were found in oligodendrocytes. Myelin breakdown was encountered very seldom.
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  • 150
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 137-152 
    ISSN: 1432-0533
    Schlagwort(e): Trembler mouse ; Peripheral neuropathy ; Electron microscopy ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The Trembler mouse is a neurological mutant showing dominant inheritance. The peripheral nerves show a delay in myelination, segmental demyelination and the development of an onion bulb neuropathy. Using electron microscopy a comparative morphometric study of nerve fibres in the sciatic nerve in normal and Trembler mice was made. The animals ranged in age from 3 days to adult. The following features were noted: 1. Mean axon diameters of the Trembler mice were smaller than normal at all ages. 2. Myelination was delayed and myelin was thinner than normal in the Trembler mice. 3. The ratio of myelin thickness to axon diameter was reduced in Trembler mice. 4. There were no significant quantitative or qualitative differences observed between middle and distal levels of Trembler nerves. The balance of evidence from these findings and the previous morphological studies is in keeping with the suggestion that the primary lesion resides in the Schwann cell.
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  • 151
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 34 (1976), S. 329-338 
    ISSN: 1432-0533
    Schlagwort(e): Muscle pathology ; Target muscle fibre ; Targetoid muscle fibre ; Histochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A large number of target fibres is observed in a muscle biopsy from a patient with an acute flaccid paraplegia of the lower limbs due to a polyneuroradiculopathy of unknown origin. With the electron microscope up to 4 structural zones are seen in the target fibers. The histochemical and ultrastructural observations in this case, suggest that the “target fibre” phenomenon is due to a disturbed trophic influence of the nervous system.
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  • 152
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 34 (1976), S. 321-327 
    ISSN: 1432-0533
    Schlagwort(e): Muscle fibres ; Amyotrophic lateral sclerosis ; Werdnig-Hoffmann disease ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Muscle biopsies from 5 cases of Werdnig-Hoffmann disease and 4 cases of ALS were investigated by histology and electronmicroscopy. The differences in morphology found in the atrophic muscle fibres in ALS and in W.H. diesease consisted mainly in the shape and structure of their cells and the number of the nuclei. Atrophic muscle fibres irregular in shape and size with degenerative changes and accumulated nuclei observed in ALS were markedly different from the picture of the fibres in W.H. disease. The presence of small muscle cells uniform diameter with well preserved architecture and single nuclei and numerous myotube-like cells seem to indicate a foetal defect in children with W.H. disease.
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  • 153
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 47-54 
    ISSN: 1432-0533
    Schlagwort(e): Entrapment neuropathy ; Fusiform nerve enlargement ; Segmental demyelination ; Axonal changes ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This paper reports on the study of a symptomless fusiform enlargement of the superficial peroneal nerve. The swelling was located in the part of the nerve passing through the aponevrosis. On incision of the epineurium small swellings were seen in the nerve fascicles. A fascicular biopsy was done and the fascicles studied by teasing and by optic and electron microscopy. Isolated nerve fiber study gave evidence of segmental demyelinisation with subsequent remyelinisation in almost all the myelinated fibers. These abnormalities were only encountered in the swollen part of the fascicle. A striking proliferation of cells was demonstrated in isolated fibers by counter-staining with hematoxylin. Electron microscopy showed primary demyelinsation and cellular proliferation affecting Schwann-cells (without onion bulb formations), fibroblasts and giant-vacuolated histiocytes. There was also a massive increase of endoneurial fluid. A few Büngner bands were seen. These rare abnormalities appear to be caused by chronic irritation of the nerve in its passage through the aponebrosis.
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  • 154
    ISSN: 1432-0533
    Schlagwort(e): Experimental malignant Schwannomas ; Melanin and melanogenesis ; Tissue and organ culture ; Electron microscopy ; Pigmented nerve sheath tumors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Four melanin pigment-containing intracranial tumors were found in three Long-Evans rats in the course of experimental oncogenesis by transplacental ethylnitrosourea (ENU). One of them was a leptomeningeal melanoma. Aside from the presence of scattered melanin-pigmented cells, the other three had the typical histological features of ENU-induced malignant nerve sheath tumors. Two of the three tumors were studied by electron microscopy and in tissue and organ culture systems. One of them demonstrated progressive melanogenesis in vitro; the other failed to produce more melanin and showed increasing differentiation, with a Schwannoma-like pattern by light microscopy. Melanosomes and premelanosomes were identified in both tumors by electron microscopy; the other fine structural features were those of malignant Schwannomas. These observations are relevant to the controversy on the histogenesis of pigmented nerve sheath tumors occasionally encountered in man and on the relationship of these tumors to pigmented nevi. The findings in the present study support the view of Masson that neoplastic nerve sheath cells are capable of melanogenesis.
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  • 155
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 93-107 
    ISSN: 1432-0533
    Schlagwort(e): Substantia nigra ; Gunn rat ; Complex membranous bodies ; Bilirubin ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The substantia nigra of various aged hyperbilirubinemic (Gunn) rats was studied by means of electron microscopy. The cytological features observed in the neuronal somata were the presence of (1) complex membranous bodies (CMBs), (2) dilated cisternae of granular endoplasmic reticulum, (3) single membrane bound vacuoles and (4) enlarged mitochondria. Nearly every neuronal soma studied in two week old Gunn rats contained CMBs, which consisted of several layers of membrane that usually, but not always, surrounded small islands of cytoplasm. On occasion CMBs were seen to be directly connected with granular endoplasmic reticulum and, in a few instances, they were located within a cistern of endoplasmic reticulum. There were significantly fewer CMBs in the neuronal somata of adult Gunn rats. They were located peripherally in the somata or in the proximal portions of dendrites. Furthermore, in these animals the cytoplasm appeared normal and did not exhibit the features commonly seen in younger animals. Only a few hyperchromatic neurons were observed and no pronounced gliosis was evident. Therefore it is assumed that the majority of substantia nigra neurons recovered from the toxic effect of bilirubin or that the concentration of bilirubin deposited in the substantia nigra is not sufficient to be lethal. The hypothesis that is considered is that CMBs represent autophagic activity which results from exposure of neurons to bilirubin. The adjacent neurites and glia did not demonstrate the cytoplasmic changes that were characteristic of the neuronal somata.
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  • 156
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 31-38 
    ISSN: 1432-0533
    Schlagwort(e): Whipple's disease ; Central nervous system ; Granulomatous infiltration ; Electron microscopy ; Bacillary bodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Whipple's disease presenting as a neurological disease without gastrointestinal symptoms is an unusual occurrence. A 40 year old man suffered hypersomnia, memory loss and progressive ophthalmoplegia for 6 months prior to death. The nature of his disease was not established during life. Extensive granulomatous inflammation affecting the hypothalamus, hippocampus and periaqueductal gray matter of the brain was found to represent Whipple's disease by electron microscopy. Characteristic lesions were also present in spleen, mesenteric lymph nodes, small intestine and myocardium. Bacillary bodies and membranous inclusions similar to those seen in visceral lesions of Whipple's disease were present in macrophages. The findings supported the theory of direct involvement of the central nervous system by bacilli rather than a metabolic origin for the lesions.
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  • 157
    ISSN: 1432-0533
    Schlagwort(e): Experimental malignant Schwannomas ; Organ culture ; Electron microscopy ; Differentiation ; Microtubules ; Basal lamina ; Perineurial fibroblasts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The sequential electron microscopic features of six malignant nerve sheath tumors (three cranial and three spinal) induced in rats by transplacental ethylnitrosourea and maintained in organ culture systems were compared with those of a human acoustic Schwannoma similarly cultured. After 4 weeks in vitro, the malignant tumor cells often showed progressive elongation of their processes, with the development of an interdigitating pattern resembling that seen in well-differentiated Schwannomas. This was accompanied by an increase of microtubules. Basal lamina formation, less well-developed and less complete than in the benign Schwannoma in this study, was maintained in culture. Some explants demonstrated an increase in number and width of collagen fibrils, accompanied by a relative concomitant decrease of intercellular basement membrane material. The malignant tumor cells also showed numerous micropinocytotic vesicles and various junctional complexes, which are characteristic of perineurial cells. Since the origin of the experimental tumors from adult Schwann cells seems well established, this apparent contradiction is best resolved by the concept that Schwann cells and perineurial fibroblasts are functional variants of the same cell type.
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  • 158
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 1-12 
    ISSN: 1432-0533
    Schlagwort(e): Cytoplasmic vacuole ; Oligodendroglia ; Brain edema ; Metastatic carcinoma ; Glioma ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Vacuolation of oligodendroglia, a new type of cytopathological change, has been described. The change is observed frequently at the perifocally edematous cerebral white matter adjacent to the metastatic lesions of carcinoma from the lung in all three cases examined. It is also present occasionally in association with astrocytoma. This condition is characterized by swelling of oligodendroglias due to numerous cytoplasmic vacuolations which contain the material identical with that of the extracellular edema fluid. In such cells, the nucleus is displaced and deformed by vacuoles but the nuclear chromatin and envelopes are arranged normally. By occupation of numerous large vacuoles the cytoplasm is divided into small areas, but the individual organelles are only minimally altered. The oligodendroglial vacuolation seems to be a phagocytic response to the edema fluid which contains proteinous macromolecules derived from blood-borne protein and necrotic material of brain tissue and neoplastic cells. The vacuolation may result in some oligodendroglial dysfunction in maintenance of myelin and probably be related with diffuse loss of myelin sheath in the longstanding brain edema secondary to neoplastic invasion. The vacuolated cells can be identified with light and electron microscopes in Epon-embedded sections of surgically removed tissue but not in paraffin sections.
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  • 159
    Digitale Medien
    Digitale Medien
    Springer
    Journal of neurology 211 (1976), S. 111-124 
    ISSN: 1432-1459
    Schlagwort(e): Peripheral nerve ; Peroneal muscular atrophy ; Nerve biopsy ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei 2 Patienten mit progressiver neuraler Muskelatrophie wurden Nervenbiopsien jeweils in einem frühen und in einem fortgeschrittenerem Stadium der Erkrankung entnommen und verglichen. In beiden Fällen zeigten bereits die frühen Biopsien ein völliges Fehlen der großkalibrigen, dickbemarkten Axone. Ebenfalls als frühe Veränderung wurde eine Erweiterung des endoneuralen Interstitiums festgestellt. Eine geringe Anzahl der vorhandenen bemarkten und unbemarkten Axone in allen Biopsien wies degenerative Veränderungen auf. Die für die progressive neurale Muskelatrophie typische Zwiebelschalenbildung der Schwannschen Zellen — möglicherweise eine Reaktion auf wiederholte De-und Remyelinisierungsvorgänge um dystrophische Axone — trat erst in den späteren Biopsien deutlicher hervor. Hinsichtlich der formalen Genese der hypertrophischen Neuropathie bei neuraler Muskelatrophie sind nach diesen Beobachtungen axonale Dystrophie und interstitielle Veränderungen des Endoneuriums als primäre Entmarkung und Zwiebelschalenbildung als sekundäre Phänomene zu betrachten. Die Möglichkeit einer kausalen Beziehung zwischen axonaler Dystrophie und interstitiellen Veränderungen wird an Hand der vorliegenden Befunde und Literatur diskutiert.
    Notizen: Summary Serial nerve biopsies were performed at an early, and at an advanced stage of the disease in 2 patients with progressive neural muscular atrophy. The early biopsy showed a complete loss of the large diameter and thickly myelinated fibres, as well as an expansion of the endoneurial interstitium in both cases. Myelinated and unmyelinated fibres exhibited axonal degeneration in all biopsies occasionally. “Onion bulb” formation, a typical feature of peripheral neuropathy in neural muscular atrophy, was found to be prominent only in the latter biopsies. As regards the formal pathogenesis of hypertrophic neuropathy in neural muscular atrophy, axonal dystrophy and interstitial changes of the endoneurium were regarded as primary phenomena, demyelination and “onion bulb” formation as secondary. A possible causal relation between axonal dystrophy and interstitial changes, observed in these cases, is discussed in the light of the present literature.
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  • 160
    ISSN: 1432-072X
    Schlagwort(e): d-Ribulose 1,5-diphosphate carboxylase ; Oxygenase activity ; Quaternary structure ; Electron microscopy ; Alcaligenes eutrophus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract d-Ribulose 1,5-diphosphate carboxylase has been purified from autotrophically grown cells of the facultative chemolithotrophic hydrogen bacteriumAlcaligenes eutrophus. The enzyme was homogeneous by the criteria of polyacrylamide gel electrophoresis. The molecular weight of the enzyme was 505000 determined by gel filtration and sucrose density gradient centrifugation, and a sedimentation coefficient of 18.2 S was obtained. It was demonstrated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis that the enzyme consists of two types of subunits of molecular weight 52000 and 13000. Electron microscopy on the intact and the partially dissociated enzyme lead to the construction of a model for the quaternary structure of the enzyme which is composed of 8 large and 8 small subunits. The most probable symmetry of the enzyme molecule is 4:2:2. Michaelis constant (K m ) values for ribulose 1,5-diphosphate, Mg2-, and CO2 were 0.59 mM, 0.33 mM, and 0.066 mM measured under air. Oxygen was a competitive inhibitor with respect to CO2 suggesting that the enzyme also exhibits an oxygenase activity. The oxygenolytic cleavage of ribulose 1,5-diphosphate was shown and a 1:1 stoichiometry between oxygen consumption and 3-phosphoglycerate formation observed.
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  • 161
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 107 (1976), S. 99-107 
    ISSN: 1432-072X
    Schlagwort(e): Piptocephalis unispora ; Mucorales ; Kickxellaceae ; Electron microscopy ; Germination ; Spore swelling ; Sporangiospore
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Germination of the sporangiospore of Piptocephalis unispora Benjamin, observed by means of light and electron microscopy, involved the formation of a new inner wall which became continous with the inner layer of the wall of the germ tube. The outer wall layer of the germ tube was continous with the original inner wall layer of the dormant spore. Preliminary details of appressorium structure were noted. Nutritional experiments indicated that sporangiospores required external sources of utilisable nitrogen and carbon compounds for maximal swelling and germ tube production. Limited development occurred when either nutrient was supplied singly. Comparison of germination of the asexual spore with that in other Mucorales, especially the Kickxellaceae, has been made, and the merosporangial status in P. unispora discussed.
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  • 162
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 107 (1976), S. 113-114 
    ISSN: 1432-072X
    Schlagwort(e): Achlya ; Electron microscopy ; Nuclear microfilaments ; Antheridia ; Mycology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This is the first report of intranuclear microfilaments within gametangial nuclei of oömycetous fungi. Longitudinal sections of four to six microfilaments were frequently observed in meiotic antheridial nuclei of Achlya ambisexualis. Each microfilament measured approximately 7–10 nm in diameter. Spindle tubules (25 nm in diameter) were also observed within some of the nuclei possessing microfilaments.
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  • 163
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 109 (1976), S. 195-197 
    ISSN: 1432-072X
    Schlagwort(e): Cell wall ; Peptidoglycan ; Electron microscopy ; Bacillus subtilis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Isolated cell walls of Bacillus subtilis have a striated appearance in the electron microscope. The structure persists when teichoic acids are removed. It is inferred that the structure bears on the arrangement of the peptidoglycan chains.
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  • 164
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 108 (1976), S. 231-242 
    ISSN: 1432-072X
    Schlagwort(e): Phytophthora ; Penetration ; Eucalypts ; Roots ; Electron microscopy ; Appressoria ; Plugs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The mechanisms of penetration of Phytophthora cinnamomi Rands into seedling eucalypt roots were studied by light and electron microscopy. Culture grown seedlings of root-rot tolerant Eucalyptus st johnii and root-rot susceptible Eucalyptus obliqua were inoculated with both zoospores and mycelium. Zoospores encysted on roots of both species and the germ tubes penetrated without the formation of appressoria. Swellings, previously described as appressoria, were formed when the germ tube was slow to enter the host by intracellular penetration. Vegetative hyphae penetrated both inter- and intracellularly into the zones of root elongation and differentiation, often through root hairs. Evidence of hydrolysis of the host cell-wall at the point of penetration was observed in electron micrographs. Several hours after the germ tube penetrated the epidermis, a thick plug of amorphous material formed in the germ tube slightly below the level of the outer walls of the epidermal cells, sealing off the hypha within the root. Behaviour of zoospores and germ tubes and the mechanism of penetration were similar on both hosts. Micrographs do not suggest any kind of a hypersensitive reaction by the host cells during the early stages of infection.
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  • 165
    Digitale Medien
    Digitale Medien
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    Archives of microbiology 107 (1976), S. 313-320 
    ISSN: 1432-072X
    Schlagwort(e): Micrococcus radiophilus ; Micrococcus radioproteolyticus ; Bacterial cell walls ; Fine structure ; Electron microscopy ; Taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The radiation resistant bacteria Micrococcus radiophilus and M. radioproteolyticus were studied by thin sectioning and freeze-etching techniques and the two species were found to be similar in the fine structure. The only significant difference was in the appearance of the surfaces of the cell walls in freeze-etched preparations. Since the two species, together with M. radiodurans, possess a unique cell wall structure and a cell wall peptidoglycan, which is different from that of other micrococci and Gram-positive cocci, it is recommended that they be reclassified into a new genus.
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  • 166
    Digitale Medien
    Digitale Medien
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    Archives of microbiology 108 (1976), S. 55-64 
    ISSN: 1432-072X
    Schlagwort(e): Bdellovibrio ; Spirillum ; Cell wall ; Bdelloplast ; Lipoprotein ; Peptidoglycan ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In both freeze-etched and critical-point dried preparations examined by transmission and scanning electron microscopy, respectively, the outer surfaces of the cells of Spirillum serpens VHL assume a wrinkled appearance 10–15 min after challenge by Bdellovibrion bacteriovorus 109D. This wrinkling effect is believed (on circumstantial evidence) to be caused by the bdellovibrio's disruption of the cell wall lipoprotein of the Spirillum. With the exception of those topological changes caused by wrinkling, the outer membrane of the Spirillum cell wall retains a normal appearance as viewed in freeze-etched preparations, even after the Spirillum cell has been converted into a bdelloplast. Although the peptidoglycan layer of the Spirillum cell presumably is weakened somewhat by the invading Bdellovibrio, evidence obtained from freeze-fractured preparations of Spirillum bdelloplasts suggests that the peptidoglycan remains as a discrete cell wall layer, even though the Spirillum cell wall apparently has lost much of its rigidity. That the peptidoglycan backbone remains essentially intact, even after the Spirillum cell has been entered by the Bdellovibrio, is supported by the observation that the soluble amino sugar content of the culture medium, as determined by chemical analysis, does not rise even 5.0 h after the association of the Bdellovibrio with the Spirillum has begun.
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  • 167
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 109 (1976), S. 21-30 
    ISSN: 1432-072X
    Schlagwort(e): Electron microscopy ; Allomyces ; Gametes ; Fertilization ; Membrane fusion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The gametes and the process of fertilization were examined by light and electron microscopy in the lower eukaryote Allomyces macrogynus. Differences in gamete morphology included the overall larger size and the presence of a larger nuclear apparatus, along with the association of a side-body complex and many more mitochondria in the female gamete. In this species of Allomyces, fertilization was initiated by contact and fusion of specialized regions of the gamete plasma membranes resulting in a binucleate fusion cell surrounded by plasma membrane contributed by both partners. Following plasmogamy, nuclear fusion was initiated by multiple nuclear membrane contacts between adjacent outer membranes. Following inner membrane fusion, small nucleoplasmic bridges were observed which presumably fused with one another and resulted in a single bridge which widened, forming the mature diploid nucleus. After karyogamy, fusion of the nuclear caps did not always occur and zygotes with and without fused caps were observed. Coalescence of the nucleoli completed the events of fertilization, forming a zygote with a single nuclear apparatus (sometimes with two caps) and two flagella. These observations are discussed in relation to fertilization mechanisms and compared to fertilization in other organisms.
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  • 168
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 107 (1976), S. 167-182 
    ISSN: 1432-072X
    Schlagwort(e): Ectothiorhodospira mobilis ; Photosynthetic membranes ; Electron microscopy ; Isolation of membranes ; Structure of membranes ; Composition of membranes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The lamellar membrane stacks of Ectothiorhodospira mobilis were isolated and purified by a combination of lysozyme and osmotic shock treatment, followed by differential and density gradient centrifugation. Preparations of lamellar membranes were enriched at least 2.4-fold in the ratio of bacteriochlorophyll a to protein. Thin-sectioning, negative staining, platinumcarbon shadowing and freeze-etching were used to study the architecture of the membrane units. Both platinum-carbon shadowing and freeze-etching showed the outer surfaces of the isolated lamellar membrane stacks to be relatively smooth. Particles averaging 7 nm in diameter were seen on several faces following freeze-ctching. Non-polar amino acids amounted to 60% of the total amino acid composition. Lipids constituted 32% of the membrane dry weight. Phosphatidyl ethanolamine and diphosphatidyl glycerol were the major phospholipids. Fatty acids of 10–15 carbons represented a small fraction of both membrane and whole cell fatty acids. Monoenes constituted 36% of the total membrane fatty acids and 38.4% of the total whole cell fatty acids. The major fatty acids of both whole cells and purified membranes were C16:0, C18:1 and cyclopropane C19:0.
    Materialart: Digitale Medien
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  • 169
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 111 (1976), S. 175-183 
    ISSN: 1432-072X
    Schlagwort(e): Serratia marcescens ; (Phage tail) bacteriocin ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Genese eines phagenschwanzähnlichen Bacteriocins in Zellen des Gruppe A-bacteriocinogenen (bA+) Serratia marcescens-Stammer Nr. 16 wurde nach Mitomycin C (MC) Induktion elektronenoptisch untersucht. Dieses Bacteriocin (Gesamtlänge 117 nm) besteht aus einem hohlen Stift mit kontraktiler Scheide. Nach 60 min Induktion wurden in Dünnschnitten stäbchenförmige Bacteriocine identifiziert. Sie erscheinen in drei Aggregationsformen: 1. als hexagonale Einschlüsse, 2. als Bänder dicht nebeneinanderliegender Bacteriocine und 3. als Stapel von übereinanderliegenden Bacteriocinschichten, wenn nach 120 min Induktion ein Maximum von ca. 450 Bacteriocinen pro Zelle erreicht wird. Bacteriocine konnten nach der gleichen Induktionszeit von 60 min auch mit der “in situ lysis technique” nachgewiesen werden. Neben Bacteriocinen traten relativ selten und unregelmäßig auch Phagenköpfe auf. Die Stäbchenform teilungsfähiger Zellen blieb bis zum Auftreten von intracellulären Bacteriocinen erhalten. Ihre Umwandlung in geblähte, sphäroplastenähnliche Zellformen, die nach 120 min Induktion lysierten, war zeitlich korreliert mit Feinstrukturveränderungen der Zellwand.
    Notizen: Abstract The biosynthesis of a phage tail-like Bacteriocin by cells of the group A-bacteriocinogenic (bA+ Serratia marcescens strain no. 16 after induction with mitomycin C (MC) was examined electronmicroscopically. This bacteriocin (total length 117 nm) consists of a hollow core and a contractile sheath. At 60 min following induction, rod-like bacteriocin-partieles were identifiable in ultrathin sections. The particles were found to comprise three morphologically different forms of aggregation: 1. hexagonal inclusions, 2. contiguous, bank-like particles, and 3. staples of superimposed layers of bacteriocin particles. At 120 min after induction bA+ cells revealed maximally 450 bacteriocin particles. Similarly, the phage tail particles could be demonstrated with the “in situ lysis technique” at 60 min following induction. Occasionally, phage heads were demonstrable, but in no instance were complete phage particles discernible. Dividing cells of the bA+ strain of S. marcescens maintained their rod-form following induction with MC until intracellular phage tail bacteriocin particles were seen. However, at 120 min after induction, the swollen, sphaeroplast-like cells lysed, an event that could be correlated with fine structural alterations of the cell wall.
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  • 170
    ISSN: 1432-2013
    Schlagwort(e): Tissue culture ; Fluorescence histochemistry ; Electrophysiology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Irides from 3–5 day old rats have been grown 1–3 mm from superior cervical or lumbar paravertebral sympathetic ganglia in modified Rose chambers. The two muscles of the iris received distinctly different innervation patternsin vitro, and these were similar to those seenin vivo. Varicose, adrenergic fibres were consistently associated with the dilator pupillae rather than with the sphincter pupillae while excitatory, cholinergic junctions developed between the nerve fibres and the muscle cells of the sphincter but not the dilator. There was a lack of specificity shown by the sympathetic neurons during this innervation. Fibres from lumbar ganglia formed plexuses within the dilator similar to those formed by superior cervical fibres, and sympathetic, cholinergic fibres were able to substitute for the normal parasympathetic, cholinergic fibres in the sphincter.
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  • 171
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 371 (1976), S. 273-282 
    ISSN: 1432-2307
    Schlagwort(e): Nasopharyngeal angiofibroma ; Fibroblast ; Vascular cells ; Fibromatosis ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An electron-microscopic study of 9 nasopharyngeal angiofibromas was performed in order to elucidate the ultrastructural characteristics. Stromal fibroblasts and proliferating cells of the microvasculature were found. The stromal fibroblasts were subdivided into 3 different groups: (1) “classical” fibroblasts, (2) fibroblasts with histiocytelike features, and (3) fibroblasts with myoid features. By proliferation the cells of the capillary vessels change into stromal cells. A particular pattern of nuclei and dense intranuclear granules is only found in stromal fibroblasts. Consequently fibroblasts as well as cells of the microvasculature contribute to the pool of tumor cells.
    Materialart: Digitale Medien
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  • 172
    ISSN: 1432-2307
    Schlagwort(e): Human heart ; Innervation ; Fluorescence histochemistry ; Electron microscopy ; Catecholamines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The existence of both adrenergic and cholinergic innervation of the atrial myocardium of the adult human heart was demonstrated by means of fluorescence induced by formaldehyde or glyoxylic acid and by electron microscopy. The adrenergic fluorescing axons (1) followed the course of blood vessels as typical perivascular nerve plexuses, and (2) formed a three-dimensional fairly dense nerve net obviously not related to the blood vessels. The varicosities frequently came into close apposition on myocardial cells. Several types of nerve terminals were differentiated at electron microscopy: (1) an “adrenergic” type containing small (diameter 450–700 Å) dense-cored vesicles and usually (in various proportions) small “empty” and/or large (900–1500 Å) dense-cored vesicles, (2) a “cholinergic” type containing small (ca. 500 Å) “empty” vesicles and occasionally also some large (mean diameter ca. 1200 Å) dense-cored vesicles, (3) a “pale” type containing only a few or no vesicles, (4) a “disintegrated” type containing degenerated mitochondria, autophagic vacuoles, and occasional normal-looking mitochondria, (5) nerve terminals containing a large number of mitochondria in addition to varying vesicle populations, and (6) a (possibly baroreceptive type of) nerve terminal containing myelinlike lamellated structures. The “disintegrated” and the “pale” types of nerve terminals possibly represent different stages of axonal degeneration, or may correspond to diminution in the transmitter substance concentration under certain pathophysiologic conditions, respectively. Nerve terminals crowded with mitochondria may be sensory and involved in mechano-or chemoreceptive functions. In preliminary experiments convincing evidence was obtained that the glyoxylic acid-induced fluorescence histochemical method will be suitable for comparative studies on (human) clinical specimens, e.g., for analyzing the degree of the functional activity of the intrinsic adrenergic innervation of the myocardium under various pathophysiologic conditions. The modification which appeared most appropriate for such studies is described in detail, and is proposed for use as a standard method in other similar or related studies on human clinical series. The essential criteria for analyzing the specimens at fluorescence microscopy are suggested as well.
    Materialart: Digitale Medien
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  • 173
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 170 (1976), S. 95-112 
    ISSN: 1432-0878
    Schlagwort(e): Baroreceptors ; Carotid sinus ; Mechanoreceptors ; Electron microscopy ; Fluorescence histochemistry ; Guinea pig, mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A light and electron microscopic study was undertaken on the baroreceptor axon terminals in the carotid sinus of guinea pigs and mice, using serial semithin and thin sections. Together with their enveloping Schwann cells, numerous lanceolate axon terminals are organized into a well-defined discoid end organ, referred to as the ‘baroreceptor unit’. Baroreceptor units measure 100 to 150 μm in diameter and are arranged in a hexagonal pattern. These end organs represent free branched lanceolate mechanoreceptors of complex type (Andres and von Düring, 1973) which belong to the main group of stretch receptors. In the guinea pig the lanceolate terminals enter the media and approach the innermost layers near the intima. In the mouse the terminals are seen to spread in the adventitia and along the medio-adventitial border. Only a few of them penetrate the external elastic layer. Species differences concerning the localization and extent of these visceral mechanoreceptors are discussed, as well as the modified architecture of the sinus wall in the receptor area (‘elastic segment’). Lanceolate terminals form beaded varicosities which are equipped with finger-like or lamellar axoplasmic protrusions. These projections contain a well-differentiated receptor matrix. They are attached to collagen and elastic fibers. The varicosities include densely packed mitochondria, neurotubules, profiles of axoplasmic reticulum, clear and granular vesicles, and striking accumulations of glycogen particles, lamellated bodies and lysosomes. Four types of varicosities are discerned according to their main axoplasmic components. Various types of these varicosities occur within an individual lanceolate terminal. The adrenergic innervation of the carotid sinus was studied by fluorescence histochemistry. In guinea pigs a multilayered wide-meshed plexus of fluorescent fibers occurs in the adventitia where it is closely related to baroreceptor stem fibers. However, adrenergic axons do not enter the media. In mice fluorescent fibers are extremely rare in the adventitia of the carotid sinus.
    Materialart: Digitale Medien
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  • 174
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 171 (1976), S. 285-296 
    ISSN: 1432-0878
    Schlagwort(e): Prostate ; Rat ; Castration ; Nuclear alterations ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fine structure of the nuclei of epithelial cells of the dorsal lobe of the rat prostate were studied 2, 3, 5, 7 and 21 days after castration. The nucleolus appears to undergo a progressive disorganisation with partial fragmentation and dispersion of its normal components. Changes in the nucleoplasm were primarily reflected by a condensation of chromatin, particularly along the nuclear membrane and adjacent to the nucleolus. Later, different types of intranuclear inclusions were observed. After 21 days, the nuclei were characterized by an irregular outline with large indentation. Within the nucleoplasm aggregates of coarse granular chromatin were found. No cell necrosis was observed, indicating that androgen deprivation results in a remodeling of the cell to a less active state with marked cellular alterations and cessation of secretion, but apparently with some of their basic functions still intact. Injections of testosterone completely reverse the castrated-induced alterations. The changes observed are assumed to be due to the withdrawal of the androgenic stimulus, with a direct influence on the secretory function of the cell. The findings support the view that the stimulating secretory effect of androgen is mediated via an intranuclear androgen receptor, probably located in the nucleolus-associated-chromatin. It is also proposed that the secretory function of the epithelial cells of the prostatic complex, initiated by androgens, may be regulated by an intranuclear secretory center.
    Materialart: Digitale Medien
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  • 175
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 173 (1976), S. 315-324 
    ISSN: 1432-0878
    Schlagwort(e): Nucleolus ; Fibrillar centre ; Nucleolar organizer ; In vitro and in vivo ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Nucleoli were studied in chick fibroblasts cultured in vitro, under normal or under experimental conditions, and in several mammalian cell types in vivo. All these cells frequently contain nucleoli with fibrillar centres. The nucleolar fibrillar centres are composed of fibrous material of low electron density and are always intimately associated with the dense fibrillar component. Their morphology is very similar to that analysed cytochemically in Ehrlich tumour cells. It therefore appears that they could be related to the nucleolar organizers as suggested in Ehrlich tumour cells.
    Materialart: Digitale Medien
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  • 176
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 165 (1976), S. 171-184 
    ISSN: 1432-0878
    Schlagwort(e): Glio-interstitial tissue ; Muscle cells ; Aplysia ; Dorid nudibranchs ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The muscular walls of the buccal mass and the oesophagus of Aplysia rosea and Glossodoris tricolor were studied by electron microscopy. The cytological features of the muscle cells, neuro-muscular junctions and a neuro-glial junction are described. This junction between an axon and a teloglial process, in the oesophagus of Aplysia, possesses all the cytological differentiations of a typical molluscan synapse. Particular attention is drawn to the distribution of the glio-interstitial tissue and the size of the extracellular spaces in these muscular organs. The classification of these muscle into ‘tonic’ and ‘phasic’ types is discussed. From this study and other data, it is concluded that the development of the glio-interstitial tissue in the muscular organs of molluscs is correlated with the size of the extracellular spaces rather than with the type of contraction of the muscle.
    Materialart: Digitale Medien
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  • 177
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 173 (1976), S. 451-460 
    ISSN: 1432-0878
    Schlagwort(e): Cardiac sarcomeres ; Tmetonyx cicada (Crustacea) ; T-tubules ; Sarcoplasmic reticulum ; Couplings ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The membrane systems of the cardiac muscle cell of the amphipod Tmetonyx cicada (O. Fabricius) are described. The sarcolemma invaginates and forms a transverse network of tubules at the level of the Z band. Narrow longitudinal tubules branch from the network and connect to another transverse network of tubules at the H band level, where dyadic and triadic junctions are formed with the sarcoplasmic reticulum. Adjacent myofibrils are normally separated by a well developed double layer of the sarcoplasmic reticulum. In areas where the myofibrils closely approach the outer sarcolemma, peripheral couplings have been found at the level of the H band.
    Materialart: Digitale Medien
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  • 178
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 174 (1976), S. 99-108 
    ISSN: 1432-0878
    Schlagwort(e): Axonal spheroids ; Spinal cord ; Rabbit ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Within the gray matter and the white matter of the spinal cord of apparently healthy rabbits, myelinated and unmyelinated axonal swellings, so called “axonal spheroids”, occur. Most of the spheroids contain mitochondria, dense bodies, vesicles and fragments of the tubular or smooth endoplasmic reticulum. In myelinated spheroids the process of swelling is effected by slippage of the myelin leaflets. At the periphery of the unmyelinated parts of the spheroids, synapses are regularly found. The presynaptic terminal bouton is formed by the spheroid. A few myelinated and unmyelinated spheroids are packed with fine granular material while mitochondria are lacking. The axonal spheroids may represent a physiological, perhaps age dependent phenomenon.
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  • 179
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 174 (1976), S. 281-288 
    ISSN: 1432-0878
    Schlagwort(e): Striated muscle ; Guinea-pig urethra ; Innervation ; Morphology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Light and electron microscopic techniques have been used to determine the distribution, morphology and innervation of subepithelial striated muscle cells in the wall of the proximal urethra of the male guinea-pig. These cells form a continuous layer, immediately beneath the urethral epithelium extending from the bladder neck to the termination of the ejaculatory ducts into the proximal urethra. They differ from “typical” striated muscle fibres (as seen in the external urethral sphincter) by their small size, rich acetylcholinesterase content and the irregular arrangement of intracellular myofilaments and sarcoplasmic reticulum. In addition, motor end plate regions have not been observed on these striated cells when examined using a light microscopic histochemical technique. The cells are related to acetylcholinesterase positive nerves which run between them in a manner compatible with the occurrence of “en passant” synaptic interactions. Using electron microscopy, axonal varicosities containing small (50 nm diameter) agranular vesicles are encountered 50 nm from the striated cells; membrane specialisations characteristic of motor end plates have not been observed on the cells. The findings are discussed, particularly in relation to the distribution, unusual morphology and innervation of these subepithelial muscle cells.
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  • 180
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 174 (1976), S. 427-430 
    ISSN: 1432-0878
    Schlagwort(e): Chromatoid body ; Acrosome ; Electron microscopy ; Myxine glutinosa L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Eine vorübergehende enge Beziehung zwischen dem Chromatoiden Körper und dem sich entwickelnden Acrosom wird in jungen Spermatiden von Myxine glutinosa demonstriert.
    Notizen: Summary A transient close relationship between the chromatoid body and the developing acrosome is demonstrated in early spermatids of Myxine glutinosa.
    Materialart: Digitale Medien
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  • 181
    ISSN: 1432-0878
    Schlagwort(e): Ecdysial gland (crab) ; Regression ; Rhizocephalan parasite ; Absorptive roots ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ecdysial glands (Y organs) of the crab Carcinus maenas regress in the presence of an external parasite, Sacculina carcini. This regression is more or less severe and may lead to complete autolysis. Three gradual stages in this involutionary process are described. In stage I, the gland cells are nearly normal. Nuclei and cytoplasmic organelles remain unchanged, but large vacuoles begin to appear. Stage II corresponds to more or less drastic nuclear pyknosis and cytoplasmic alterations. Myelin figures are large and numerous. Lysosomes and autophagic vacuoles with phosphatase activity are abundant. However, the general cellular architecture remains preserved. Stage III corresponds to irreversible cytolysis; nuclear envelopes and plasma membranes have disappeared. What remains is an accumulation of cellular debris becoming engulfed by circulating hemocytes. Not all of the gland cells of any given Y organ show the same degree of regression; degeneration is asynchronous. Structures seemingly corresponding to absorptive roots of the parasite are seen. Their lumen is coated with microvilli. The putative direct and indirect influences of the rhizocephalan parasite on its host are discussed. Our results on regressing Y organs of parasitized crabs are compared with those on regressing ecdysial glands of insects.
    Materialart: Digitale Medien
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  • 182
    ISSN: 1432-0878
    Schlagwort(e): Neurosecretory granules ; Morphometric classification ; Neurohypophysis ; Hagfish, Eptatretus burgeri ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Neurosecretory axons in the neurohypophysis of the hagfish, Eptatretus burgeri, were statistically classified into six types according to the size of secretory granules. These types are comparable with those in higher vertebrates. The concentration of each axon type is different in three regions: anterior dorsal wall, posterior dorsal wall, and ventral wall. The regional differences of the hagfish neurohypophysis are discussed in relation to the regional differentiation of the tetrapod neurohypophysis into the median eminence and the pars nervosa.
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  • 183
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 33-43 
    ISSN: 1432-0878
    Schlagwort(e): Human fetal pancreas ; Endocrine cells ; Argyrophil reactions ; Light microscopy ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The endocrine cells in the pancreas of five human fetuses with gestational ages of 18–20 weeks were examined by light and electron microscopy with special regard to argyrophil reactions. B-cells and typical A and D-cells were easily identified electron microscopically on the basis of their typical secretory granules. In the Grimelius argyrophil silver stain, a concentration of silver grains over the less electron dense peripheral mantle of the A-cell secretory granules was observed by electron microscopy. In the Hellerström and Hellman modification of the argyrophil Davenport alcoholic silver stain, silver grains were concentrated over the internal structures of the D-cell secretory granules. With this stain an accumulation of silver grains was also seen at the surface of the A-cell secretory granules. The argyrophil reaction of the A-granules was less pronounced than in the D-cells. In addition to B-cells and A- and D-cells, two other types of endocrine cell were observed by electron microscopy. These cells were argyrophil with the silver impregnation method of Grimelius. The electron microscopic findings at least partly explain the frequent overlapping between the two staining methods observed at the light microscope level.
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  • 184
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 89-99 
    ISSN: 1432-0878
    Schlagwort(e): Osteoclast ; Protein export ; Lysosome ; Electron microscopy ; Autoradiography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The present electron microscopic autoradiographic study includes a quantitative analysis of osteoclasts in vitro using tritiated leucin as a protein tracer. A significant increase in the grain density over the ruffled border and the underlying resorption zone was demonstrated two hours post pulse whereas the grain density of the remaining cytoplasm was relatively constant. This indicates a transport of newly synthesized protein from the osteoclast to the extracellular resorption zone. Earlier histochemical and biochemical experiments suggest that the exported protein may represent lysosomal enzymes to be used in the extracellular bone degradation.
    Materialart: Digitale Medien
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  • 185
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 133-140 
    ISSN: 1432-0878
    Schlagwort(e): Thyroid gland ; Follicle cell ; Junctional complex ; Freeze fracturing ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Zonulae occludentes, gap junctions and desmosomes have been demonstrated in replicas of freeze-fractured follicular cells of normal human and rabbit thyroid glands. The zonulae occludentes between the human follicular cells are composed of two to eight strands, which completely separate the intercellular space from the follicular lumen. Four to twelve or more strands are visible between the follicular cells of the rabbit thyroid gland. In the meshes of the zonulae occludentes as well as below them, gap junctions are present. They are numerous on the fracture faces of the human follicular cell membranes, but infrequent in those of the rabbit. Aggregates of particles related to desmosomes are found in the deeper meshes of the zonulae occludentes or close to them.
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  • 186
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 175 (1976), S. 369-390 
    ISSN: 1432-0878
    Schlagwort(e): Electron microscopy ; Crustacea ; Synaptic vesicles ; Biogenic amines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The appearance and distribution of dense-core vesicles in the stomatogastric ganglion of the spiny lobster, Panulirus interruptus, were examined using transmission electron microscopy. Following five fixation techniques, three types of dense-core vesicles were identified on the basis of size and morphology. Type-I vesicles are found in a distinct neuronal fiber system that appears to be involved in chemical transmission within the ganglion. Type-II vesicles occur in nerve processes in the ganglion, in major nerve trunks and in the perineural sheath of the nerves and ganglion. Type-III vesicles are present in all neuronal somata of the ganglion. The distinct morphology and location of the three types of vesicles suggest that their functional roles differ. Furthermore, the histochemical, biochemical and physiological data available for the Stomatogastric ganglion indicate that Type-I vesicles may store dopamine.
    Materialart: Digitale Medien
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  • 187
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 277-287 
    ISSN: 1432-0878
    Schlagwort(e): Proteoglycans ; Odontoblasts, predentin, dentin ; Calcification ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The localization of proteoglycans in the predentin of the rat incisor was investigated by ultrastructural histochemistry. Ruthenium red stained the cell coat of the odontoblasts as well as intracellular vesicles. There was also a staining of the extracellular matrix, but not of collagen fibers in the predentin. Treatment with the enzyme hyaluronidase prior to staining with ruthenium red abolished the staining of the vesicles and the extracellular matrix but not that of the cell coat. Bismuth nitrate and phosphotungstic acid gave similar staining of odontoblast vesicles and extracellular matrix. It is likely that the stained structures contain proteoglycans. The importance of these proteoglycans and their ultrastructural localization are discussed in relation to intracellular transport and the calcification process.
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  • 188
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 175 (1976), S. 403-416 
    ISSN: 1432-0878
    Schlagwort(e): Mammals ; Mole ; Male genital system ; Accessory sex organs ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The mole has a single pair of accessory sex organs with features of both the prostate and the seminal vesicle, for which the term prostate gland is not appropriate. Seasonal changes occurring in this gland were related to four periods: a) the quiescence period, b) the maturation period, c) the active period and d) the involution period. During the quiescence period the cuboidal epithelial cells display a quasi-embryonic fine structure and are sparse in cytoplasmic organelles, but rich in glycogen and lipopigment. With the onset of sexual activity glycogen and lipopigment disappear and the rough endoplasmic reticulum as well as the Golgi apparatus begin to proliferate. The fully active gland is lined by a low epithelium with parallel stacks of rough endoplasmic reticulum, a large Golgi apparatus and several lysosomes and secretory granules. In the involution period the gland collapses and the epithelial cells are eliminated by hetero-and autophagic processes. During this period a great number of presumably endocrine cells were observed. The results were compared with findings in experimental studies and those on postnatal development of accessory sex glands in laboratory animals.
    Materialart: Digitale Medien
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  • 189
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 179-195 
    ISSN: 1432-0878
    Schlagwort(e): Islets of Langerhans ; Horse pancreas ; Cell types ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Das Inselorgan der Bauchspeicheldrüse des Pferdes wurde an immersions- und perfusionsfixiertem Material untersucht. Dabei ließen sich nach der Immersions- wie Perfusionsfixation fünf Zelltypen unterscheiden: 1. A-Zellen, die im Zentrum der Insel liegen, 2. B-zellen, die hauptsächlich blasse Granula enthalten und den größten Teil der Inselperipherie ausmachen, 3. D-Zellen, die ebenfalls vorwiegend in der Inselperipherie liegen, 4. G-Zellen, die am Rand der Inseln und im exokrinen Pankreas anzutreffen sind, 5. S-Zellen (“small granule cells”), die relativ selten und nur in den Inseln zu finden sind. Über die Funktion und altersabhängigen Veränderungen dieser Zellen wird diskutiert. Die Bildung von hellen und dunklen Zellen halten wir für ein Artefakt, ebenso die Bildung von sog. Mischzellen, da diese Zelltypen nur nach Immersionsfixation auftreten.
    Notizen: Summary The islets of Langerhans of the equine pancreas were examined with the electron microscope after immersion or perfusion fixation. Five cell types could be distinguished after fixation by either technique: 1. A-cells, situated at the center of the islets, 2. B-cells, containing mostly “pale granules” and constituting the principal cell type of the periphery of the islets, 3. D-cells, also located mainly at the periphery of the islets, 4. G-cells, found at the edge of the islets and in the exocrine pancreas, and 5. S-cells, (small granule cells), which are relatively few in number and occur only in the islets. The function and age-dependent modifications of these cells are discussed. The formation of light and dark cells and of “mixed cells” are regarded as artifact, since cells of this type occur only under the condition of immersion fixation.
    Materialart: Digitale Medien
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  • 190
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 265-288 
    ISSN: 1432-0878
    Schlagwort(e): Myelinated fibres ; Visual cortex ; Stereology ; Development ; Electron microscopy ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary With the aid of stereological procedures the development of myelinated nerve fibres (MF) was quantitatively investigated in electron micrographs of the visual cortex from animals of different ages: 36 days-old, the age at which fibres first appear, through adulthood. A short description of tissue treatment, methods and qualitative results is given. The following quantitative results are presented: 1. Myelinization begins at about the 36th day postpartum and is not completed by the 164th day. At this time a lack of about 20% MF can be observed. 2. The average diameter of MF decreases from 1.3 μm to 0.8 μm from day 36 to adulthood. 3. The first MF appear near the border of the album. 4. Beginning with the 55th day, small MF arise in layer I, showing two periods of growth. 5. The maximum MF density in the region of layer IV corresponds to the strip of Baillarger. Other aspects of visual cortex development are dealt with in the Discussion. The following conclusions can be drawn: a) The growing of inand output-MF is completed first. b) The development of the internal connecting systems in layers I and IV begins a little later and is completed by the 5th month. c) The MF in layers II and III appear after the 4th month. Kaes (1907) has also described a continuation of MF growth in man lasting into the twenties.
    Materialart: Digitale Medien
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  • 191
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 363-371 
    ISSN: 1432-0878
    Schlagwort(e): Synapses ; Synaptogenesis ; Dense projections ; Cerebral cortex ; E-PTA ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The molecular layer of rat occipital cortex was studied at a number of ages throughout postnatal development in an attempt to formulate a quantitative morphogenetic scheme of synaptic development. As previous work had pointed to the potential usefulness of E-PTA stained material in synaptogenic studies, this technique was employed. Synaptic junctions were assigned to five categories, A-E, on the basis of variations in the organization of their presynaptic densities. Of these categories, Type A represented a mature junctional form with well-defined and discrete dense projections. Type E, by contrast, represented the immature end of the spectrum, its presynaptic apposition generally lacking recognizable densities. Types B-D represented intermediate forms. As development proceeded, the percentage of A type junctions increased from 0.3% at 7 days to 25% in the adult. Type E junctions showed the opposite trend falling from 42% at 7 days to 5% in the adult. On the basis of these results, and those relating to types B-D, possible morphogenetic schemes involving the five synaptic categories are put forward. These schemes incorporate and extend those previously suggested by other workers. By placing observations on a quantitative footing, the schemes proposed here lend themselves to use in experimental investigations.
    Materialart: Digitale Medien
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  • 192
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 373-385 
    ISSN: 1432-0878
    Schlagwort(e): Gills ; Salmo gairdneri ; Specialized endothelia ; Arteriovenous anastomoses ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The origin of arterio-venous anastomoses, connecting the efferent filament artery (EFA) with the central venous sinus (CVS) of gill filaments can be well discerned by scanning electron microscopy in the rainbow trout. Corresponding vessels between the afferent filament artery and the CVS could not be detected with the techniques applied. AVA-specific endothelial cells are characterized by their bulky shape and their microvillous surface. The general morphology of AVA's in Salmo gairdneri is very similar to that of AVA's in Tilapia mossambica (Vogel et al., 1974) but they are much longer in the trout. No filament whorls have been encountered in AVA endothelia of Salmo gairdneri.
    Materialart: Digitale Medien
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  • 193
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 527-536 
    ISSN: 1432-0878
    Schlagwort(e): Endometrium ; Innervation ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The innervation of the endometrium of rabbit, rat, mink, mongoose and pig has been investigated electron microscopically. Large bundles of nerve fibers can be observed in the connective tissue spaces within the basal layer of the endometrium. Unmyelinated nerve fibers enter the lamina functionalis, terminal nerve fibers penetrate the basal lamina and make contact with the glandular and the cavum epithelial cells. The terminal axons contain abundant synaptic vesicles, dense core vesicles and mitochondria. To date, no specialized presynaptic or postsynaptic membranes have been found.
    Materialart: Digitale Medien
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  • 194
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 563-567 
    ISSN: 1432-0878
    Schlagwort(e): Trigeminal ganglion ; Dorsal root ganglia ; Continuous endothelium ; Fenestrated endothelium ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Several fenestrated capillaries were seen in the endoneurium of trigeminal and dorsal root ganglia from two young adult albino rats treated with tetraethylthiuram disulfide. The finding is regarded as normal, although the possibility exists that intoxication with tetraethylthiuram disulfide may have enhanced the intensity and/or rate of this cytologic specialization of some isolated endothelial cells.
    Materialart: Digitale Medien
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  • 195
    ISSN: 1432-0878
    Schlagwort(e): Adrenal cortex ; Mitochondria ; ACTH ; Stereology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effects of chronic administration of ACTH (up to 36 consecutive days) on the mitochondria of the zona reticularis of the rat adrenal cortex were investigated by stereologic techniques. It was found that ACTH induces two phases of hypertrophy of mitochondria alternating with two proliferative stages, which are associated with a significant decrease in the average volume of the organelles. It is suggested that, as in the zona fasciculata, ACTH controls the processes of growth and division of mitochondria in the zona reticularis. The mechanism underlying this action of ACTH as well as the differences between the responses to ACTH of the mitochondrial population of the two adrenal zones are discussed in the light of evidence indicating that mitochondria contain a complete genetic apparatus largely independent of nuclear control.
    Materialart: Digitale Medien
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  • 196
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 45-53 
    ISSN: 1432-0878
    Schlagwort(e): Juxtaglomerular apparatus ; Exocytosis ; Microtubules ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The epithelioid cells of the juxtaglomerular apparatus have been studied with respect to the release mechanism of the secretory granules. Invaginations of the plasma membrane into the interior of the epithelioid cells are interpreted as stages before or after an exocytotic process. Granules are sometimes observed in close contact with the plasma membrane, and material with electron density similar to that of the granules can also be observed in the invaginations. These morphological features suggest that the granular material of the epithelioid cells is extruded into the texture of the basal lamina. Furthermore, a dense network of microtubules and microfilaments is described and the functional role of this system in exocytosis is discussed.
    Materialart: Digitale Medien
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  • 197
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 65-78 
    ISSN: 1432-0878
    Schlagwort(e): Muscle fibre types ; Axolotl (Ambystoma mexkanum) ; Morphometry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Morphometric analysis by light microscopy of p-phenylene-diamine stained semithin sections of axolotl tail muscle revealed differences in the cross-sectional area of the fibres and in the number of mitochondria and of lipid inclusions per fibre, and indicated the presence of three distinct types of fibres. The tripartition was found to be statistically highly significant. Representative fibres from each group established by light microscopic morphometry were subjected to an ultrastructural morphometric analysis. The volume content of mitochondria amounted to 9.8% of the fibre volume for red, 4.0% for intermediate and 0.8% for white fibres. The myofibrils composed 60%, 70% and 83% in the same fibres. The volume of the sarcotubular system (t-tubuli and sarcoplasmic reticulum) was 2.5% in red, 4.5% in intermediate and 11.7% in white fibres. The three fibre types also demonstrated differences in myofibrillar cross-striation pattern and number of triads. The reliability of the light microscopic morphometry was tested by correlation with EM montages of the representative fibres.
    Materialart: Digitale Medien
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  • 198
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 170 (1976), S. 89-94 
    ISSN: 1432-0878
    Schlagwort(e): “C” cells ; Endoplasmic reticulum ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Multiple rough endoplasmic cisternae were found in “C” cells of the adult rat, at interphase. They are considered to be normal constituents of “C” cells. Their morphological relation to rough endoplasmic reticulum and their close proximity to mitochondria, Golgi dictyosomes and secretory granules suggest that they may have a role in the secretory activity of this endocrine cell.
    Materialart: Digitale Medien
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  • 199
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 170 (1976), S. 549-551 
    ISSN: 1432-0878
    Schlagwort(e): Optic gland ; Octopus ; Uptake of ferritin ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Horse spleen ferritin, injected into the blood of the octopus, leaves the capillaries via pericyte junctions and windows. One hour after the administration, ferritin has entered the optic gland main cells; three hours later, it is accumulated in dense-bodies. The evidence for resorption supports earlier papers reporting that the ultrastructure of the organ is unusual for an endocrine gland.
    Materialart: Digitale Medien
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  • 200
    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
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