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  • 2025-2025
  • 2015-2019
  • 2000-2004
  • 1990-1994  (74)
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  • 1
    Digitale Medien
    Digitale Medien
    Rhabdoid tumours of the central nervous system (1993)
    Springer
    Virchows Archiv 422 (1993), S. 81-85 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Rhabdoid tumour ; Central nervous system ; Immunocytochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Three cases of rhabdoid tumour of the central nervous system arising in a supratentorial location are reported. The patients were 18, 14, and 7 years old. All three tumours showed a common morphology. The neoplastic cells were usually globoid with round nuclei and prominent nucleoli and large acidophilic, cytoplasmic inclusions were present in many of them. These inclusions showed strong immunoreactivity for vimentin, weak immunoreactivity for epithelial membrane antigen and focal immunoreactivity for cytokeratins. Ultrastructurally they were made up of whorls of intermediate filaments, 8–10 nm in thickness. Rhabdoid tumours of the central nervous system, whatever the cell of origin, appear to be an independent entity with identifiable histology and aggressive behaviour.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01605137
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  • 2
    Digitale Medien
    Digitale Medien
    Localized amyloidosis in squamous cell carcinoma of uterine cervix: Electron microscopic features of nodular and star-like amyloid deposits (1993)
    Springer
    Virchows Archiv 422 (1993), S. 225-231 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Amyloid ; Amyloidosis ; Squamous cell carcinoma ; Keratin ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract An ultrastructural study of amyloid deposits in four cases of squamous cell carcinoma of uterine cervix was performed. The amyloid deposits reacted with anti-keratin antiserum on frozen sections. Amyloid deposits showed nodular (4 cases) and star-like forms (3 cases). Nodular amyloid deposits were composed of slightly whorled fibrils, measuring 7–10 nm in width. Some of them contained cellular debris and thicker, more electron-dense filaments than amyloid fibrils. In three cases, filamentous tumour cells and filamentous masses were observed together with amyloid. Star-like amyloid deposits were composed of bundles of straight amyloid fibrils. Some of the tumour cells in contact with star-like amyloid deposits had deep cytoplasmic invaginations, where closely packed amyloid fibrils were arrayed in parallel fasion. In addition, a few tumour cells had membrane-bound amyloid fibrils in the cytoplasm. It is suggested that nodular amyloid deposits are derived from the tumour cells through filamentous degeneration. Amyloid fibrils in star-like amyloid deposits are thought to be formed within the cytoplasm or in the vicinity of invaginated cytoplasmic membranes of the tumour cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01621806
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  • 3
    Digitale Medien
    Digitale Medien
    Widening of capillary neck and alteration of extracellular matrix ultrastructure in diabetic rat glomerulus as revealed by computer morphometry and improved tissue processing (1993)
    Springer
    Virchows Archiv 423 (1993), S. 121-129 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Ultrastructure ; Morphometry ; Diabetic nephropathy ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Morphological and morphometric studies of glomeruli were carried out in streptozotocin-induced diabetic rats using improved tissue processing and computerized morphometry. Increased mesangial matrix, occupying the enlarged diabetic mesangium, contained an abundance of dark granular material in addition to the microfibrils which were usually found in the control glomeruli. In the diabetic glomeruli, the lamina densa was thick and heterogeneous showing a dense layer both on its epithelial and endothelial aspects, and the lamina rara externa contained more fibrils than in control rats. Detailed estimation of the absolute values of the various compartments of the diabetic glomeruli by using perfusion-flxed materials and a computer-assisted digitizer revealed that the volume and surface area of the mesangium were increased more extensively than those of the capillary; the enlargement of the mesangial-capillary interface area was the most pronounced among the morphometric changes of the diabetic glomeruli; and that the moderate increase in capillary volume was associated with an increased radius. Our quantitative results showed that capillaries in the diabetic glomeruli had an extensively wider neck which may be the first sign of structural damage to the glomerular tuft.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01606586
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  • 4
    Digitale Medien
    Digitale Medien
    Altered intestinal development after jejunal ligation in fetal sheep (1993)
    Springer
    Virchows Archiv 423 (1993), S. 45-50 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Fetus ; Small intestine ; Ultrastructure ; Intestinal atresia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Experimental obstruction of the fetal small intestine resulted in massive hypertrophy of the segment proximal to the site of obstruction. Villus morphology was grossly abnormal. Enterocytes developed many irregular features, most notably cytoplasmic extensions (pseudopods, or blebs) from their apical surface. Distal to the site of obstruction, morphological anomalies which resembled those seen after experimental oesophageal ligation were found. These included delayed disappearance of the apical endocytic network, disrupted or absent microvilli, glycogen accumulation and inappropriate cell extrusion. Proximal to the obstruction, where stasis of swallowed fluid occurs, distension and abnormal intestinal development ensues. Distal to the obstruction where the intestine develops in the absence of swallowed fluid, development is also abnormal. The anomalies resemble those noted after oesophageal ligation in utero, and possibly are the results of reduced cellular nutrition. These results suggest that fetal ingestion provides the developing gastrointestinal tract with an important stimulus for normal growth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01606431
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  • 5
    Digitale Medien
    Digitale Medien
    Comparative study of histopathological alterations during intestinal infection of mice with pathogenic and non-pathogenic strains ofYersinia enterocolitica serotype O:8 (1993)
    Springer
    Virchows Archiv 423 (1993), S. 97-103 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Yersinia enterocolitica ; Peyer's patches ; Ultrastructure ; M-cell ; Invasiveness
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Yersinia enterocolitica is an invasive pathogen capable of causing a wide spectrum of gastrointestinal diseases in man. While there is a considerable body of data on the invasiveness ofY. enterocolitica in vitro, little is known about the events in vivo leading to the translocation of the bacteria from the intestinal lumen into the ileal tissue. There is no detailed ultrastructural information describing the course of infection of pathogenicY. enterocolitica in comparison with an avirulent strain. We compared a virulent plasmid-bearing strain and an isogenic avirulent plasmid-free derivative strain ofY. enterocolitica serotype O∶8 at the ultrastructural level, in the established model of murine yersiniosis. At 12 h postinoculation we found no indications of an active invasion of the intestinal epithelium, although microcolonies of the pathogenic strain were detectable closely under the follicle-associated epithelium of the Peyer's patches. The plasmid-bearing strain ofY. enterocolitica affected the gut-associated lymphoid tissue which was destroyed 36 h post-infection. Unlike the pathogenic strain ofY. enterocolitica, the nonpathogenic plasmid-free strain caused no detectable morphological alterations in the ileal tissue by this time. Morphological evidence is provided thatYersinia does not invade the ileal epithelium in an active manner, as has been observed in vitro, but appears to be transported across the epithelial barrier by M-cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01606583
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  • 6
    Digitale Medien
    Digitale Medien
    Cytogenetic study of botryoid rhabdomyosarcoma of the uterine cervix (1993)
    Springer
    Virchows Archiv 422 (1993), S. 87-91 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Botryoid rhabdomyosarcoma ; Uterine cervix ; Immunohistochemistry ; Ultrastructure ; Chromosomal analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We report a case of sarcoma botryoides of the uterine cervix occurring in a 19-year-old woman. By light microscopy the tumor showed round and spindle cells with hyperchromatic nuclei and, focally, a cambium layer subjacent to the surface epithelium and surrounding endocervical glands. Strap-shaped cells with and without cross-striations and small foci of immature cartilage were also present. Immunohistochemical studies showed positive staining within the tumor cells for myoglobin, desmin, vimentin, muscle-specific actin and CD56. By electron microscopy, tumor cells showed cytoplasmic filaments in an alternating pattern of thick and thin filaments. Chromosomal analysis demonstrated deletion of the short arm of chromosome 1, and trisomies 13 and 18. To our knowledge, this is the first reported case of sarcoma botryoides of the endocervix with chromosomal analysis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01605138
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  • 7
    Digitale Medien
    Digitale Medien
    Cellular and matrix changes in drug abuser liver sinusoids: A semiquantitative and morphometric ultrastructural study (1993)
    Springer
    Virchows Archiv 422 (1993), S. 145-152 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Heroin ; Sinusoids ; Fibrosis ; Ultrastructure ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The aim of the present work was to analyse, at the ultrastructural level, the action of heroin of 150 centrilobular sinusoids from liver biopsies of five intravenous drug abusers, who presented clinical and biological manifestations of hepatic impairment. A comparative study of 90 sinusoids from liver biopsies of three control patients was performed. Electron microscopic observations showed a thickening of the sinusoidal wall related to endothelial cell hypertrophy and to fibrosis of the space of Disse. This was generally associated with basement-membrane-like material and hepatocyte microvilli flattening. In addicts, hepatic vascular pole changes were a constant finding, accompanied by interhepatocyte space disjunction and perisinusoidal collagenization. Morphometric assessment confirmed a significant increase of sinusoidal wall surface, endothelial cell body and processes and Ito cell process surface was significantly different between the patient groups. This cellular hypertrophy may represent hyperactivation of the sinusoidal cell functional capacity, triggering the fibrogenesis in the space of Disse. While this mechanical barrier might hinder the free exchange through the space of Disse, it may equally well protect the liver against heroin toxicity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01607166
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  • 8
    Digitale Medien
    Digitale Medien
    Ultrastructural study ofCryptococcus neoformans by quick-freezing and deep-etching method (1993)
    Springer
    Mycopathologia 121 (1993), S. 133-141 
    Details
    ISSN: 1573-0832
    Schlagwort(e): Capsule ; Cryptococcus neoformans ; Deep-etching ; Quick-freezing ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The three-dimensional ultrastructure ofCryptococcus neoformans was studied by quick-freezing and deep-etching (QF-DE) method.C. neoformans, strain CDC551, was cultured on agar. The viable yeast cells (107 cells) were inoculated into each mouse from the tail vein. Three weeks after the inoculation, the brains of the mice were perfused with fixatives, quickly frozen, freeze-fractured, deeply etched and rotary shadowed with platinum and carbon. In addition, the viable cells ofC. neoformans on agar were picked up and quickly frozen, and replica membranes were prepared as described above. The ultrastructure ofC. neoformans was three-dimensionally demonstrated by the QF-DE method. The capsule was composed of fine meshworks of microfibrils (10–13 nm in diameter), which were directly attached to the cell walls. The capsule of the in vivo yeasts (yeast cells in the brain lesion) was thicker than that of the in vitro yeasts (yeast cells on agar culture). At the outer part of the cell wall, a particle-accumulating layer was observed. This layer in vivo was thicker than that in vitro. Occasionally, the yeast cells were ingested by phagocytes in the mouse brain. Although the cytoplasm of such yeast cells was destroyed, the capsular meshworks were well preserved. The ultrastructure of the capsule was the same both in cultured and phagocytized yeasts in the cystic lesions of the brains. This lack of morphological changes of the capsular meshworks suggests that they are resistant to the digestion by phagocytes. This stability of capsular structures may provide one of the important pathogenic factors in cystic lesions byC. neoformans.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01104068
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  • 9
    Digitale Medien
    Digitale Medien
    Morphological assessment of ethyl choline mustard aziridinium-induced neurotoxicity in rat brain reaggregate cultures (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 154-162 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Ethylcholine mustard aziridinium (ECMA, AF64A) ; Brain reaggregate cultures ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Foetal rat brain reaggregate cultures have been employed to investigate the morphological changes associated with the neurotoxic action of ethylcholine mustard aziridinium (ECMA). In a companion study we provided evidence for apparent selective cholinergic neurotoxicity. Exposure of 9-day-old cultures to 12.5 μM ECMA for 3 days produced dilatation of selected axon preterminals and terminals in the outer core tissue layer. Axoplasm in these dilated terminals was electron lucent and contained a flocculent, plasma-like material with remnants of the smooth endoplasmic reticulum. Their synaptic vesicle content was much reduced or, absent. Microglial cells were engaged in phagocytosis of these effete structures and a few necrotic neurons were enveloped by glial processes. Exposure to 50 μM ECMA produced widespread necrosis with some surviving neurons, surrounded by the still-persisting capsular layer. Treatment with 100 μM ECMA generated a greater extent of tissue necrosis, with only a few surviving neurons and glial cells being contained within the necrotic tissue mass. Reaggregates frequently disintegrated following capsule loss. Our results indicate that the initial morphological manifestation of ECMA-induced toxicity is dilatation of axon terminals, that are probably of cholinergic origin and are targeted due to their possession of the high-affinity choline transport system which is unique to these neurons.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00334882
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  • 10
    Digitale Medien
    Digitale Medien
    Nephrosialidosis: ultrastructural and lectin histochemical study (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 198-205 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Nephrosialidosis ; Sialidosis ; α-neuraminidase deficiency ; Ultrastructure ; Lectin histochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The neuropathological findings in a Japanese male with nephrosialidosis are reported. Clinically, coarse face, psychomotor retardation, macular cherryred spot and proteinuria were noted at 1 year and 7 months. He was diagnosed to have nephrosialidosis on the basis of a deficiency of α-neuraminidase activity in both lymphocytes and cultured skin fibroblasts, and of severe glomerular and tubular involvement on renal biopsy. He died of multiple organ failure at 8 years and 6 months. There were numerous vacuoles and storage materials in visceral organs, particularly in the glomerular and tubular epithelial cells of the kidney and Kupffer cells as well as hepatocytes in the liver. Neuropathological examination revealed severe neuronal storage in the selected part of the central nervous system; lower motor neurons of the brain stem and spinal anterior horn cells, as well as neurons in the basal nucleus of Meynert. In the peripheral nervous system, sympathetic ganglia were severely affected. There was little or no neuronal storage in the basal ganglia, cerebral cortex or cerebellum, and demyelination was not found. Electron microscopic examination showed fine wavy multilamellar structures in the spinal anterior horn cells or Zebra body-like structures in the neurons of the Meynert's basal nucleus. Lectin histochemistry was positive for wheat germ agglutinin, Ricinus communis agglutinin-1 and peanut agglutinin within distended neurons. We conclude that the neuropathological feature in nephrosialidosis is not specific except for the selectiveness of the anatomical sites of involvement. It shares some aspects found in other types of sialidosis or galactosialidosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00334891
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  • 11
    Digitale Medien
    Digitale Medien
    A simple method of rapid freezing adequately preserves brain tissue for immunocytochemistry, light and electron microscopic examination (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 645-650 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Brain ; Freezing ; Immunocytochemistry ; Microscopy ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A simple and reproducible method for cryo-preservation of brain tissue from patients with Alzheimer's disease is described. Fresh brain slices (1 cm thick) obtained less than 6 h postmortem are placed in sealed plastic bags, sandwiched between 0.3-cm-thick aluminium sheets, and frozen by placing the entire “sandwich” between layers of dry ice pellets. The frozen brain slices are stored at −85 °C. Specific anatomic areas can be retrieved at any time for light and electron microscopic, immunocytochemical, autoradiographic and neurochemical studies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00294305
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  • 12
    Digitale Medien
    Digitale Medien
    Stereological and morphometric analysis of dermal fibroblasts before and after bone marrow transplantation in a case of mucopolysaccharidosis I Scheie phenotype (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 21-28 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Mucopolysaccharidosis I Scheie phenotype ; Bone marrow transplantation ; Fibroblasts ; Stereologic analysis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Bone marrow transplantation (BMT) has been used therapeutically in several types of mucopoly-saccharidoses (MPS) and other inherited metabolic disorders. Fibroblasts are severely affected in MPS due to the intralysosomal accumulation of glycosaminoglycans. We report a stereological and morphometric study at light and electron microscopy levels of dermal fibroblasts before and 21 months after BMT in a young girl with MPS I Scheie phenotype (MPS I-S). Dermal fibroblasts showed remarkable morphological changes although their density, expressed as number of fibroblasts per unit volume of dermis (number density), was not modified in the post-BMT samples as compared to pre-BMT ones. Stereological and morphometric parameters referring to cell characteristics of post-BMT fibroblasts (nuclear and cell surface densities, and both nucleus/cell and cell/nucleus volume densities) showed significant differences when compared with pre-BMT fibroblasts, and non-significant differences regarding control cells. On the other hand, quantitative parameters of the lysosomal compartment from post-BMT fibroblasts showed intermediate values between pre-BMT and control fibroblasts. These results, at cellular level, are in agreement with previous biochemical and clinical results, and clearly showed a progressive course to a non-pathological state. All parameters estimated may be considered useful tools in evaluating the success of BMT. These parameters provide quantitative data which can be statistically compared, showing the changes due to the reduction of storage material after BMT. Cell/nucleus volume density is especially interesting since not only is it easy to estimate, even by automatic procedures, but it could also constitute a numerical expression of skin anatomopathological analyses performed post-BMT.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00454894
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  • 13
    Digitale Medien
    Digitale Medien
    Rosenthal fibers producing a granular cell appearance in a glioblastoma (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 100-104 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Glioblastoma ; Granular cell tumor ; Intermediate filaments ; Rosenthal fibers ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In this report we describe a glioblastoma multiforme with focal granular cell change. In most astroglial tumors with granular cells, the granular appearance is due to the presence of periodic acid-Schiff-positive, membrane-bound cellular debris. In the present case the granular appearance was due to the presence of many small Rosenthal fibers, which were immunoreactive for glial fibrillary acidic protein, vimentin, ubiquitin, and heat-shock protein 27, but not for α-B crystallin. The ultrastructural characteristics are described. These findings demonstrate that granulofilamentous inclusions with the appearance of Rosenthal fibers in glial tumors are a structurally heterogeneous feature.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00454907
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  • 14
    Digitale Medien
    Digitale Medien
    Intracranial extraskeletal myxoid chondrosarcoma with special reference to lamellar inclusions in the rough endoplasmic reticulum (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 525-528 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Extraskeretal myxoid chondrosarcoma ; Ultrastructure ; Collagen type II ; Rough endoplasmic reticulum ; Lamellar inclusion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract An extraskeletal myxoid chondrosarcoma in the pineal region was studied by light and electron microscopy. The immunohistochemical positivity for S-100 protein, vimentin and collagen type II favored a chondrocytic origin of the tumor. In addition to the well-described ultrastructural features suggestive of a cartilagenous nature, this tumor had unusual lamellar inclusions in the rough endoplasmic reticulum. To the best of our knowledge, this is the first report of these special inclusion bodies in a myxoid chondrosarcoma.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00228591
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  • 15
    Digitale Medien
    Digitale Medien
    Uncommon types of polyglucosan bodies in the human brain: distribution and relation to disease (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 484-490 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Polyglucosan bodies ; Bielschowsky bodies ; Adult polyglucosan body disease ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The significance of the development of polyglucosan bodies (PBs) in the CNS is incompletely understood. We present the clinicopathological features of three autopsy cases with numerous PBs other than the common corpora amylacea or Lafora bodies. The first patient had pleomorphic PBs in the neuronal processes of pallidum and substantia nigra which, thus, are consistent with Bielschowsky bodies. Bielschowsky bodies involved also the hypothalamus and tegmentum of midbrain and medulla. The present case was the first not associated with any clinical symptoms. The second patient also had incidental Bielschowsky bodies in the external pallidum, substantia nigra, and pallidothalamic, pallidonigral and nigrostriatal tracts. Additionally, unique clusters of small PBs appeared in the cerebral cortex, putamen, pallidum, and caudate nucleus. Immunostaining suggested that these small clustered PBs were located in the cytoplasm and processes of astrocytes. Ultrastructurally, these clustered PBs were in agreement with previous descriptions of PBs. The third patient had adult polyglucosan body disease. Most PBs in the white matter were corpora amylacea situated in astrocytic processes or axons. In the gray matter, many pleomorphic PBs resembling Bielschowsky bodies occurred in neuronal processes. In the peripheral nervous system, a few PBs were seen in myelinated axons. The following conclusions may be drawn from this study: (1) each type of PBs develops in distinct cell types of the human brain in variable distribution; (2) Bielschowsky bodies may not manifest clinically; (3) PBs other than corpora amylacea or Lafora bodies may be distributed in localized or diffuse patterns; (4) in the localized pattern (patients 1 and 2), PBs occur as Bielschowsky bodies or clustered PBs, and tend to involve certain systems (pallidum, striatum, and substantia nigra); and (5) in the diffuse pattern (patient 3), PBs develop as corpora amylacea and Bielschowsky-like bodies of adult polyglucosan body disease.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00228584
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  • 16
    Digitale Medien
    Digitale Medien
    Ontogenesis of the rabbit pituitary intermediate lobe (1993)
    Springer
    Anatomy and embryology 187 (1993), S. 87-97 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Pituitary intermediate lobe ; Rabbit ; Ontogenesis ; Immunocytochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The development of the intermediate lobe of the rabbit pituitary was investigated by light and electron microscopy and by using immunocytological techniques. The first immunoreactive melanotrophic cells were detected at the fetal day 17 in the dorsal zone of Rathke's pouch epithelium facing the neural lobe; this coincided ultrastructurally with the appearance in this area of a few cells exhibiting secretory vesicles and granular condensations in the Golgi saccules. The differentiation of the gland probably required an infundibular inductive effect. Secretory cells increased in number following a dorsoventral gradient during the next fetal and neonatal stages until postnatal day 20, the stage at which the intermediate lobe exhibited its definitive organization. The gland innervation occurred during the first days after birth. The advent of these oxytocin- and neurophysin-immunoreactive fibres coincided with an obvious stimulation of the synthetic activity of the melanotrophic cells. The possible neurotrophic effect of these cells on their innervating system remains to be established.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00208199
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  • 17
    Digitale Medien
    Digitale Medien
    The ciliary ganglion of the cat: a light and electron microscopic study (1993)
    Springer
    Anatomy and embryology 187 (1993), S. 591-599 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Ciliary ganglion ; Quantitative study ; Ultrastructure ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The ciliary ganglia of eight healthy adult cats were studied by light and electron microscopy. The ganglion, measuring about 2 mm in length, was consistently found to be attached to the branch from the oculomotor nerve supplying the inferior oblique muscle. The number of neurons varied from 2773 to 3794 after applying Abercrombie's correction. The mean of average somal diameter of the neurons was 36.5 μm (SD = 5.0 μm) and the mean of somal cross-sectional area was 904.2 μm2 (SD = 262.8 μm2). The mean of average nuclear diameter was 13.9 urn (SD = 1.8 μm) and the mean of nuclear cross-sectional area was 142.2 μm2 (SD = 37.1 μm2). The mean of the aspect ratios of the soma and nucleus were 1.2 (SD = 0.1) and 1.1 (SD = 0.1) respectively. The frequency distributions of these parameters were all unimodal. Under the light microscope, the Nissl granules in the neurons were prominent and were distributed peripherally, perinuclearly or randomly in the cytoplasm. Under the electron microscope, the rough endoplasmic reticulum showed a similar pattern of distribution in the cytoplasm. In some neurons, glycogen-like granules were present; these were either distributed randomly throughout the cell, or aligned in single rows in relation to sub-surface cisterns and between the cisterns of smooth and rough endoplasmic reticulum. Most of the dendrites were short protrusions from the cell body; some contained glycogen-like granules. Occasionally, the dendritic protrusions were electron-dense. All the synapses encountered were axodendritic. In most axon terminals, the synaptic vesicles were spherical and measured 30–50 nm in diameter; in some, they were flattened, measuring 50 nm by 20 nm. Some axon terminals containing either spherical or flattened synaptic vesicles also contained large dense-cored vesicles that measured 80–100 nm, while their dense core measured 40–60 nm.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00214438
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  • 18
    Digitale Medien
    Digitale Medien
    Morphological analysis of in vitro human hair growth (1993)
    Springer
    Archives of dermatological research 285 (1993), S. 158-164 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Hair follicle ; Culture ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The histological and ultrastructural aspect of normal human hair follicles maintained ex vivo for 12 days was evaluated. Anagen hair follicles, dissected free of contaminating connective tissue, were maintained for up to 12 days in a serum-free medium. Macroscopic observations revealed continued viability for 12 days, at which time some follicles involuted in a manner morphologically similar to catagen. Increased growth of maintained follicles was measured from the abrupt ending of the connective tissue sheath (CTS), as no increase in this component was observed from initiation of culture. In general follicles maintained up to 8 days exhibited little divergence from normal in vivo morphologies including the persistence of functional hair bulb melanocytes — a marker of anagen. After this time melanin granules were present in dermal papilla cells, as occurs during impending involution in vivo. Heterotypic cell contact occurred in the middle to upper follicle between outer root sheath (ORS) keratinocytes and disorganized CTS. Herniation of some ORS cells away from the follicle and the occurrence of loose desmosomal junctions between ORS keratinocytes reflected loss of normal follicular cell interactions in upper follicles maintained after 8 days. Continued follicle growth correlated with the presence of mitotic matrix keratinocytes even at 12 days. After 12 days in culture most follicles involuted displaying apoptotic-like keratinocytes and hair bulb melanocytes and the presence of highly keratinized hair ‘club’ structures. While most follicles exhibited this orderly sequence of events, a few follicles involuted after 24 h with synchronous degeneration of all cells. Two follicles exhibited upregulated cortical cell differentiation at the level of the dermal papilla (DP). Normal cell cytoplasmic constituents were replaced with ribosomes and keratin bundles. This study reveals for the first time the histology and ultrastructure of normal hair follicles in culture for up to 12 days in serum-free medium. Although involuted hair follicles may exhibit some features of catagen, it is possible that the mechanisms involved are entirely different.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01112919
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  • 19
    Digitale Medien
    Digitale Medien
    Mayflies (ephemeroptera), the most “primitive” winged insects, have telotrophic meroistic ovaries (1993)
    Springer
    Development genes and evolution 203 (1993), S. 18-27 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Oogenesis ; Germ line cell cluster ; Oocyte determination ; Ultrastructure ; Mayflies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Germ line cell cluster formation in ovarioles of three different stages, each from a different mayfly species, was studied using ultra-thin serial sectioning. In the analysed ovariole of Cloeön sp., only one linear, zigzag germ line cell cluster was found, consisting of sibling cells connected by intercellular bridges which represent remnants of preceding synchronized mitotic cycles followed by incomplete cytokinesis. A polyfusome stretched through all sibling cells. At the tip of the ovariole, cytokinesis occurred without preceding division of nuclei; thus, intercellular bridges were lined up but the remaining cytoplasm between the bridges had no nuclei. The analysed Siphlonurus armatus vitellarium contained five oocytes at different stages of development. Each oocyte in the vitellarium was connected via a nutritive cord to the linear cluster of its sibling cells in the terminal trophic chamber. Each cluster had the same architecture as was found in Cloëon. The 3-dimensional arrangement and distribution of closed intercellular bridges strongly suggest that all five clusters are derived from a single primary clone. The position of oocytes within each cluster is random. However, each oocyte is embraced by follicular or prefollicular cells whilst all other sibling cells are enclosed by somatic inner sheath cells, clearly distinguishable from prefollicular cells. In the analysed ovariole of Ephemerella ignita, two small linear clusters were found in the tropharium beside two single cells, two isolated cytoplasmic bags with intercellular bridges but no nuclei, and some degenerating aggregates. One cluster was still connected to a growing oocyte via a nutritive cord. In all species the nurse cells remained small and no indications of polyploidization were found. We suggest that this ancient and previously unknown telotrophic meroistic ovary has evolved directly from panoistic ancestors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00539886
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  • 20
    Digitale Medien
    Digitale Medien
    Ultrastructural expression of cytoplasmic male sterility in sugar beet (Beta vulgaris L.) (1993)
    Springer
    Sexual plant reproduction 6 (1993), S. 22-32 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Cytoplasmic male sterility ; Ultrastructure ; Mitochondria morphometry ; Beta vulgaris L
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The development of microspore mother cells (MMC) and tapetum in male-fertile and male-sterile anthers of Beta vulgaris L. was compared at the electron microscope level. These studies were complemented by morphometric analyses of mitochondria in both tissues through successive stages of microsporogenesis. The earliest irregularities in the ultrastructure of male-sterile anthers were noted within the tapetum at the tetrad stage. These disturbances were initially expressed by a slight reduction in mitochondrial size and the appearance of concentric configurations of endoplasmic reticulum. As development proceeded, a further decrease in mitochondrial size become more conspicuous and was accompanied by a reduction in ribosome population and a failure of the tapetum to produce Ubisch bodies. This failure to produce Ubisch bodies is reflected in the underdevelopment of sterile microspore exine.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227579
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  • 21
    Digitale Medien
    Digitale Medien
    Megaspore development in Selaginella. I. “Wicks”, their presence, ultrastructure, and presumed function (1993)
    Springer
    Sexual plant reproduction 6 (1993), S. 98-107 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Selaginella ; Megaspore ; Exospore ; Ultrastructure ; Tapetal cells ; Plasmodesmata
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Structures have been found in the locular space between the tapetal cells and megaspores in Selaginella argentea and S. kraussiana that enter the megaspore wall and extend to the plasma membrane of the megaspore cytoplasm. We have called these structures “wicks”. Unless special fixation procedures are used wicks are either very poorly preserved or not apparent. Wicks appear to be routes for the transport of materials from the tapetum to developing megaspores. The entry of the wicks into the megaspore wall and their passage throughout the wall implies that the megaspore wall of Selaginella is a three-dimensional mesh-work of inter-connecting spaces. Wicks have several macromolecular-sized subunits, and the results of our histochemical reactions indicated the presence of glycoprotein and/or mucopolysaccharide. X-ray microanalysis of the S. convoluta exospore showed that silicon is present in rod-shaped structures between units of the exospore in mature megaspores. Because of the size and form of the structures between the exospore units we consider that they are remnants of wicks stabilized by silicon.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227654
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  • 22
    Digitale Medien
    Digitale Medien
    Chemical agents that inhibit pollen development: effects of the phenyl-cinnoline carboxylates SC-1058 and SC-1271 on the ultrastructure of developing wheat anthers (Triticum aestivum L. var Yecora rojò) (1993)
    Springer
    Sexual plant reproduction 6 (1993), S. 108-212 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Wheat pollen ; Chemical hybridizing agents ; Male sterility ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Phenylcinnoline carboxylate compounds SC-1058 and SC-1271 cause complete male sterility in wheat when applied at suitable dosages at the pre-meiotic stage of anther development. Anthers from treated and untreated plants were compared using light and electron microscopy from the pre-meiotic stage through the formation of nearly mature pollen. Overall anther development is gradually slowed in treated plants and pollen development is generally arrested in the late prevacuolate or early vacuolate microspore stage, although the first pollen mitosis does sometimes occur. The sporopollenin-containing exine walls are thinner, and show abnormally developed foot and tectum layers with sparse connecting baculi. Microspore cytoplasm degenerates and the cells eventually collapse. At the early, prevacuolate, free microspore stage treated tapetal cells hypertrophy, expanding into the locule. They contain abnormally large vacuoles that appear to form from the fusion of secretory vesicles, and some vacuoles contain electrondense deposits. The sporopollenin-containing orbicular wall and Ubisch bodies are retarded in their development and are structurally deformed. Acetolysis of whole anthers and of thick sections shows that the sporopollen-in-containing structures of treated materials are greatly reduced in thickness and are less rigid than in the control. We conclude that application of these compounds causes interference with the secretory function of tapetal cells which supplies sporopollenin cell-wall polymers to the exine of the microspores and to the tapetal orbicular wall and associated Ubisch bodies. Interference with the tapetal secretion of other nutrients required for microspore development is strongly suggested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227655
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  • 23
    Digitale Medien
    Digitale Medien
    The embellum: a newly defined structure in the grass ovule (1993)
    Springer
    Sexual plant reproduction 6 (1993), S. 191-198 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Micropyle ; Transfer cells ; Ultrastructure ; Nucellus ; Poaceae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Several kinds of outgrowth from the grass ovule are known. Attention is focused here on one outgrowth that occurs within or around the micropyle and is of nucellar origin. Grass species in which it is currently known to occur are listed and examples of variants briefly described. Attention is concentrated upon Pennisetum, where the cell structure is described in detail with a series of electron photomicrographs. The tissue representing an aggregation of these transfer cells is newly named with the term ‘embellum’, and its significance for pollen tube growth is considered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00228648
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  • 24
    Digitale Medien
    Digitale Medien
    Ultrastructural changes in the appendix of the Sauromatum guttatum inflorescence during anthesis (1993)
    Springer
    Sexual plant reproduction 6 (1993), S. 153-170 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Appendix ; Sauromatum guttatum ; Ultrastructure ; Mitochondrion ; Amyloplast ; Peroxisome
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ultrastructure of the epidermal and sub-epidermal cells of the appendix of the Sauromatum guttatum inflorescence reveals developmental changes during anthesis. These changes precede, and probably make possible, heat and odor production. Two days before D-day (the day of heat production and inflorescence-opening) the mitochondria of the epidermis divide; apparent division of the amyloplasts was observed at the same time. The presence of lipid bodies and peroxisomes in the epidermis was clearly evident. On D-day, the epidermis becomes a continuous layer in which the cell walls separating two adjacent cells disappear. At the same time, in the sub-epidermal cells, the mitochondria and the amyloplasts undergo division. The mitochondria become electron-dense, and their DNA is clearly visible. On that day, lipids as well as starch are being depleted. The peroxisomes change in structure every day, from D-2 to D-day. It has also been demonstrated by histochemical techniques that during anthesis the activity of cytochrome c oxidase (3,3-diaminobenzidine as a substrate) decreases whereas the activity of NADH dehydrogenase [tetrazolium salts: nitro-blue tetrazolium chloride (NBT) or neotetrazolium chloride (NT) in the presence of NADH], increases. Oxygen consumption of isolated mitochondria from the D-day appendix was inhibited in the presence of the two tetrazolium salts to a different degree: oxidation of NADH in the presence of NBT was the most sensitive to inhibition, more so than the oxidation of malate and succinate. NT was less effective as an inhibitor in the presence of those three respiratory substrates.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00228644
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  • 25
    Digitale Medien
    Digitale Medien
    Ultrastructure of the cortical epithelium of the rat thymus after in vivo exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (1993)
    Springer
    Archives of toxicology 67 (1993), S. 558-564 
    Details
    ISSN: 1432-0738
    Schlagwort(e): 2,3,7,8-Tetrachlorodibenzo-p-dioxin ; TCDD ; Thymus ; Epithelium ; Ultrastructure ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is known for inducing cortical atrophy in the rat thymus. The present study was conducted to provide ultrastructural evidence for the cortical epithelium to be a target for TCDD in vivo. Juvenile male Wistar rats were orally intubated once with either 50 or 150 μg/kg TCDD and killed 4 or 10 days thereafter. Major changes were found in the cortical thymic epithelium. First, a relative shift occurred from “pale” to darker cortical epithelial cell types, as judged by their nuclear and cytoplasmic electron density. This effect was most prominent at 10 days after exposure to 150 μg/kg TCDD. The increased electron density of the cortical epithelium indicates an altered state of cellular differentiation. Secondly, at the 150 μg/kg dose level focal epithelial cell aggregates were seen both at day 4 and day 10 after administration. This aggregation may either be compound induced or represent a secondary event to the collapse of the thymic stroma. Thirdly, increased vacuolation of cortical epithelial cells was apparent. This effect is interpreted as a consequence rather than a cause of thymocyte depletion from the cortex. This study indicates that TCDD exposure affects the cortical epithelium of the rat thymus at a high dose level. Electron microscopy reveals that the differentiation of epithelial cells is altered. In addition, epithelial cell aggregates are formed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01969269
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  • 26
    Digitale Medien
    Digitale Medien
    Identification of Naemacyclus minor hyphae within needle tissues of Pinus sylvestris by immunoelectron microscopy (1993)
    Springer
    Archives of microbiology 160 (1993), S. 265-272 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Pinus sylvestris ; Naemacyclus minor ; Immunocytochemical identification ; Ultrastructure ; Plant-fungus interactions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cultural investigations revealed that Naemacyclus minor, Lophodermium seditiosum and Cenangium ferruginosum were the most frequent colonizers of asymptomatic and symptomatic Pinus sylvestris needles. Since ultrastructural observations showed that morphological features were not suitable to differentiate hyphae of N. minor from hyphae of other isolates, the on-section immunogold labelling technique was applied in combination with an anti-N. minor specific immunoserum. The specificity of this serum was tested against culture hyphae of all isolates. Anti-N. minor specific immunoserum was then used to identify N. minor hyphae in thin sections of green P. sylvestris needles. The infection loci identified were restricted to small tissue areas located in the vicinity of stomata. In the hypodermis, hyphae and endocell-containing hyphae were located within the lumina of host cells but outside the protoplast. The growth of hyphae from cell to cell occurred through pits. The hyphae spreat into the mesophyll intercellularly and continued with the intracellular colonization of moribund and dead mesophyll cells in a later stage of infection. The observed host-parasite interactions at cellular and ultrastructural level are discussed in connection with the still controversial interpretation of the pathogenicity of N. minor.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00292075
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  • 27
    Digitale Medien
    Digitale Medien
    Ultrastructure of Bacillus pulvifaciens (1993)
    Springer
    Archives of microbiology 159 (1993), S. 114-118 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Bacillus pulvifaciens ; Vegetative cells ; Spotes ; Ultrastructure ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The ultrastructure of vegetative cells and spores of Bacillus pulvifaciens was studied by CTEM and SEM methods. The vegetative cells are rods, 1.6–4.5 μm long and 0.4–0.6 μm wide, exhibiting typical ultrastructural features of Gram-positive bacteria. The spores are of ellipsoidal shape, 0.6×1.2 μm in size, with six longitudinal ribs reaching up to 130 nm in height. There are satelite ribs on both sides of the longitudinal ribs, reaching up to 20 nm in height. Between the longitudinal ribs, additional transversal ribs were observed in SEM. A special tubular layer, separating the outer and inner coat of the spores, was revealed in ultrathin sections. This layer seems to be a typical ultrastructural feature of Bacillus pulvifaciens spores.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00250269
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  • 28
    Digitale Medien
    Digitale Medien
    Development of quasi-multicellular bodies of Treponema denticola (1993)
    Springer
    Archives of microbiology 160 (1993), S. 206-213 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Treponema denticola ; Spirochetes ; Ultrastructure ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The formation of quasi-multicellular bodies of Treponema denticola was analysed using different electron microscopical methods. These bacteria could develop four different conformations: (i) normal helical forms; (ii) twisted spirochetes, forming plaits; (iii) twisted spirochetes, forming club-like structures; (iv) spherical bodies in different size. Treponemes within spherical bodies, plaits, and clubs proved to be enclosed in a common outer sheath in which the normal arrangement of their axial flagella was lost. The development of the quasi-multicellular bodies starting from the monoforme spirochetes was elucidated and this morphogenetic process is illustrated by a schematic drawing. Factors which might be involved in the induction of the structures are discussed and their possible pathogenetic importance is considered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00249126
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  • 29
    Digitale Medien
    Digitale Medien
    Avian epidermis contains ATPase- and Ia-positive Langerhans-like cells (1993)
    Springer
    Cell & tissue research 271 (1993), S. 103-106 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Skin ; Langerhans cell ; ATPase-histochemistry ; Ultrastructure ; Ia antigen ; Four avian species
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The occurrence of cells resembling mammalian Langerhans cells in the avian epidermis was studied by ATPase histochemistry, Ia immunoreactivity and electron microscopy. The existence of MHC class II antigen-(Ia) expressing, ATPase-positive dendritic cells, which are ultrastructurally similar to mammalian Langerhans cells except for the absence of Birbeck granules, was demonstrated. These cells may be a basic component of the immune system of birds.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00297547
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  • 30
    Digitale Medien
    Digitale Medien
    Development of the diffuse endocrine system in the chicken proventriculus (1993)
    Springer
    Cell & tissue research 271 (1993), S. 107-113 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Proventriculus ; Endocrine ontogenesis ; Ultrastructure ; Regulatory peptides ; Immunocytochemistry ; Silver impregnations ; Chicken
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The development of endocrine cells in the chicken proventriculus has been investigated using light-and electron-microscopy in conjunction with silver and immunocytochemical techniques. The first morphologically detectable endocrine cells were found in 5-day-old embryos by electron microscopy. From the 9th to the 13th day, endocrine cells in contact with the lumen of the organ could be detected both by electron and light (silver impregnation) microscopy. The number of open-type endocrine cells progressively decreased and the number of closed-type increased after this stage. Until the 16th day, endocrine cells were located exclusively in the luminal epithelium, but afterwards they appeared in progressively greater numbers in the compound glands. After hatching, long cytoplasmic processes could be seen in the endocrine cells. Immunoreactivities to regulatory substances appeared in the following order: serotonin (day-14), avian pancreatic polypeptide, glucagon and somatostatin (day-16), bombesin and neurotensin (day-18), and finally, met-enkephalin (day-21).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00297548
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  • 31
    Digitale Medien
    Digitale Medien
    Immunocytochemical effects of thyroxine stimulation on the adenohypophysis of dwarf (dw) mutant mice (1993)
    Springer
    Cell & tissue research 274 (1993), S. 579-585 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Thyroxine ; Pituitary gland, pars distalis ; Immunocytochemistry ; Ultrastructure ; Mouse (Snell dwarf)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The effects of dietary thyroxine on the immunoreactivity of cells in the pars distalis of the adenohypophysis in dwarf (dw/dw) mice were determined by ultrastructural immunocytochemistry. In nontreated dwarfs only adrenocorticotropic hormone (ACTH) cells and luteinizing hormone (LH) cells showed positive reactions to their respective antibodies, whereas no cells showed immunoreactivity to antibodies to growth hormone (GH), thyroid-stimulating hormone (TSH), or prolactin (Prl). In dwarfs supplemented postnatally with dietary thyroxine for 9 wks, the treatment failed to produced immunoreactive GH, TSH or Prl cells. However, LH cells became more prominent and fully developed, with denser concentrations of immunoreactive particles overlying the secretory granules than occurred in nontreated dwarfs. In thyroxine-treated dwarfs, ACTH cells were similar in ultrastructural features and immunoreactivity to those in nontreated dwarfs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00314556
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  • 32
    Digitale Medien
    Digitale Medien
    Biphasic effect of ACTH on growth of rat adrenocortical cells in primary culture (1993)
    Springer
    Cell & tissue research 271 (1993), S. 169-176 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Adrenal cortex ; Differentiation ; Tissue culture ; Proliferation ; Ultrastructure ; Steroids ; Rat (Sprague Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The proliferation rate of differentiating fetal rat adrenocortical cells was studied in primary culture. In this system, stimulation with ACTH induces differentiation of zona glomerulosa-like cortical cells into zona fasciculata-like cells. Incorporation of bromodeoxyuridine (BrdU) was studied immunocytochemically by use of anti-BrdU antibody, and the proliferation rate was counted from the monolayer colonies of adrenocortical cells. After 21 days of cultivation in the absence of ACTH, the proliferation rate of zona glomerulosa-like cells was 10%. The rate slowly declined to 1% at the age of 100 days during continuous cultivation in the absence of ACTH. Stimulation with ACTH induced a strong inhibition in the proliferation rate (down to 2% during the first 24 h). Treatment with ACTH during the following 48 h led to an extremely intense proliferation of adrenocortical cells at a proliferation rate of 25%. Continuous treatment with ACTH up to 100 days led to a persistent growth of adrenocortical cells, and a proliferation rate over 2-fold higher than in control cells cultivated in the absence of ACTH. Thus, ACTH is the principal growth-promoting factor also in vitro, as has been found in in vivo studies. This growth effect is mediated by a biphasic course; at the beginning of differentiation the effect is inhibitory and is followed by a persistent stimulation of the growth of adrenocortical cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00297555
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  • 33
    Digitale Medien
    Digitale Medien
    Ultrastructure and morphometry of testicular Leydig cells and the interstitial components correlated with testosterone in aging rats (1993)
    Springer
    Cell & tissue research 271 (1993), S. 241-255 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Leydig cell ; Testis ; Interstitium ; Aging ; Ultrastructure ; Morphometry ; Testosterone ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The ultrastructure of testicular interstitium in young and aged adult rats was analysed using morphometric methods, and the plasma testosterone concentration was measured. With increasing age there was an augumentation in the volume of collagen fibrils in the intercellular matrix and in blood vessels. During the aging process (approximately two years) the average volume of the Leydig cell decreased from 1364 μm3 to 637 μm3, but the number of Leydig cells in paired testes increased from 53x106 to 113x106. The absolute volume of smooth surfaced endoplasmic reticulum (SER) per Leydig cell amounted in aged rats to 78% of that in young adult rats. The total amount of SER in paired testes increased by 62% with aging. The present analysis suggests that the ability of SER to maintain peripheral testosterone concentration decreases with age. In young adult rats the absolute volume of peroxisomes per Leydig cell correlated significantly with the concentration of testosterone in blood and also with the absolute volume of SER per Leydig cell. These results combined with ultrastructural observations of close apposition of peroxisomes and SER suggest that peroxisomes have a role in testosterone secretion by Leydig cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318610
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  • 34
    Digitale Medien
    Digitale Medien
    Effect of omeprazole-evoked hypergastrinemia on ultrastructure of enterochromaffin-like cells in the stomach of portacaval-shunted rats (1993)
    Springer
    Cell & tissue research 272 (1993), S. 71-77 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Enterochromaffin-like cells ; Hypergastrinemia ; Hypertrophy ; Ultrastructure ; Omeprazole ; Portacaval shunt ; Rat (Sprague Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The histamine-producing enterochromaffinlike (ECL) cells in the acid-producing portion of the rat stomach responded to long-standing hypergastrinemia (omeprazole treatment daily for 8–10 weeks) with hypertrophy (and hyperplasia) and with a reduced number of granules and vesicles per unit cytoplasm. There was a reduction in the ratio of electron-dense granules versus vesicles and an increase in the profile diameter of the vesicles. Also, portacaval shunting (PCS) induced changes in the ECL cells, manifesting (i) as an increase in cell number and size, and (ii) as a reduced number of granules and vesicles per unit area. The cytoplasmic granules and vesicle profiles were enlarged, and the ratio of granules versus vesicles was reduced. The combination of PCS and long-standing hypergastrinemia (omeprazole treatment) produced a greatly enhanced ECL cell hypertrophy (and hyperplasia) and a marked reduction in the number of granules. The ratio of granules versus vesicles was markedly reduced while the profile diameters of both granules and vesicles were increased. The relative predominance of very large vesicles (vacuoles) was a prominent feature of the ECL cells in these rats.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00323572
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  • 35
    Digitale Medien
    Digitale Medien
    Ultrastructure of free nerve endings in respiratory and squamous epithelium on the rat nasal septum (1993)
    Springer
    Cell & tissue research 274 (1993), S. 329-335 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Intraepithelial axons ; Free nerve endings ; Nasal mucosa ; Ultrastructure ; Enzyme histochemistry ; Immunocytochemistry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The distribution of nerve fibres in the mucosa of the nasal septum of the rat was investigated by means of transmission electron microscopy on transverse and tangential ultrathin sections. Near the basement membrane of respiratory and squamous epithelium, a rather dense network of unmyelinated nerve fibres occurs. Some fibres in the respiratory epithelium ascend between the epithelial cells to reach up to the tight junctions. These fibres appeared in transverse sections to end as hooks or boutons, sometimes with branches. These shapes resemble the free nerve endings that are considered to act as nociceptors. The small intraepithelial fibres, with diameters of about 0.5–1 μm, contain both dense granules and clear vesicles comparable to synaptic vesicles. Substance P was found in dense granules in basal fibres; vasoactive intestinal peptide was absent throughout the epithelium. Acetylcholinesterase activity was observed closely associated with the basal fibres; the apical fibres showed little if any activity. Membrane specializations pointing to an efferent function as well as structures usually associated with mechanoreceptive functions were lacking in both respiratory and squamous epithelium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318751
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  • 36
    Digitale Medien
    Digitale Medien
    The effects of gonadectomy and testosterone treatment on the Harderian gland of the green frog, Rana esculenta (1993)
    Springer
    Cell & tissue research 273 (1993), S. 201-208 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Harderian gland ; Castration ; Testosterone ; Ultrastructure ; Rana esculenta (Anura)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The effects of gonadectomy and testosterone treatment on the fine structure of the Harderian gland in male and female green frogs were investigated in different periods of the year. Gonadectomy, carried out when the glands are in the lowest secretory phase (September), causes degenerative changes consisting of a reduction of the rough endoplasmic reticulum, the appearance of autolysosomes, and an increase of nuclear heterochromatin. These effects can be prevented by testosterone treatment. No castration effects are found during the recovery (November) and enhancement (April-May) phases of secretory activity. The results suggest that the frog Harderian gland's sensitivity to testosterone changes during the annual cycle. The androgen dependence of the Harderian gland is correlated with the presence of androgen receptors in both male and female forgs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00312821
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  • 37
    Digitale Medien
    Digitale Medien
    Carbamylcholine-induced morphological changes and spatial dynamics of [Ca2+]c in Harderian glands of guinea pigs: calcium-dependent lipid secretion and contraction of myoepithelial cells (1993)
    Springer
    Cell & tissue research 274 (1993), S. 1-14 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Harderian gland ; Ultrastructure ; Fura-2/AM digital imaging ; Calcium ion ; Carbamylcholine ; Myoepithelial cells ; Guinea pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract To determine whether lipid-secreting cells have cytosolic Ca2+ concentration ([Ca2+]c)-related secretory mechanisms, morphological changes and intracellular calcium dynamics of Harderian glands of guinea pigs stimulated by secretagogs were studied by electron microspy and Fura-2/AM digital image analysis. Control glandular cells contained large lipid vacuoles that were bordered by multi-layered membranes. Rough-surfaced endoplasmic reticulum, mitochondria, and smooth-surfaced endoplasmic reticulum may be involved in lipid vacuole formation. Myoepithelial cells surrounded alveoli. After carbamylcholine (CCh, 10−6, 10−5, and 10−3 M) stimulation, lipid materials within the membranous structures were frequently discharged by an exocytotic mechanism. Conspicuous deformation of glandular cells caused by vigorous contraction of myoepithelial cells was observed in isolated alveoli after 10−6M CCh stimulation, whereas the deformaties of glandular tissues perfused via vessels were small even after 10−3M CCh stimulation. Connective tissue between glandular alveoli inhibited unbridled myoepithelial-cell contraction. Fura-2/AM digital imaging analysis revealed that CCh stimulation caused an increase in [Ca2+]c in isolated alveoli. The morphological reactions and changes in [Ca2+]c were prevented by atropine. When extracellular calcium ions were absent, enhanced extrusion of lipid vacuoles, myoepithelial-cell contraction, and a rise in [Ca2+]c after CCh stimulation were not observed. Nicotine and catecholamines had no effect on the secretion or on the dynamics of [Ca2+]c. It can be concluded that acetylcholine elicits exocytosis in glandular cells and contraction of the myoepithelial cells of Harderian glands, accompanied by an increase in [Ca2+]c. The dynamics of [Ca2+]c of the gland alveoli are mostly dependent on extracellular Ca2+.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00327979
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  • 38
    Digitale Medien
    Digitale Medien
    Electron-microscopic immunocytochemical study of the endocrine pancreas of sea bass (Dicentrarchus labrax) (1993)
    Springer
    Cell & tissue research 274 (1993), S. 303-314 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Endocrine pancreas ; Peptides ; Ultrastructure ; Immunogold labeling ; Sea bass ; Dicentrarchus labrax ; (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Insulin (B)-, somatostatin 25 (SST-25) (D1)-, somatostatin 14 (SST-14) (D2)-, glucagon (A)-, and glucagon PP/PYY/NPY (PP-like)-immunoreactive cells in islets of sea bass (Dicentrarchus labrax) were characterized according to their ultrastructure and immunogold labeling. Cells labeled with antisera to bonito and salmon insulin had numerous secretory granules with a small halo and round core, and a few with wide halo and round or crystalloid core. Gold particles were found throughout the granule in tissue labeled with the former but only in the core in tissue labeled with the latter. D1 cells had large granules with a medium electron-dense content and some with a darker core. D2 had smaller medium or high electron-dense secretory granules than D1 cells, located mainly in cell periphery. Glucagon-immunoreactive cells contained some granules with a polygonal core that was heavily labeled and other granules with a round core with no or hardly any labeling. Glucagon and PP-like immunoreactivity were co-localized in secretory granules, in which the gold particles showed no different distribution with the various antisera used. PYY-immunoreactive granules were also found in nerve endings. All the pancreatic endocrine cell types showing involutive characteristics are found.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318749
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  • 39
    Digitale Medien
    Digitale Medien
    Cutaneous and subcutaneous sensory receptors of the hagfish Myxine glutinosa with special respect to the trigeminal system (1993)
    Springer
    Cell & tissue research 274 (1993), S. 353-366 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Trigeminal nerve ; Mechanoreceptors ; Skin ; Peripheral autonomic ganglia ; Ultrastructure ; Myxine glutinosa ; Cyclostomata
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The integument of the hagfish Myxine glutinosa is described with respect to the topography and the fine structural organization of the dermal and hypodermal nerve fiber plexus. Both nerve fiber plexuses contain small ganglion cells with axodendritic and axosomatic synapscs. The six barbels of the head (4 nasal and 2 oral barbels) are supplied with about 5600 afferent trigeminal nerve fibers via the right and left ophthalmic nerve. With respect to the topography of the sensory nerve terminals in the barbels different types of receptors are termed the external cuff receptor, internal cuff receptor, and perichondrial receptor. Free nerve terminals occur within the epidermal layer, especially at the tip region of the barbels and in the glassy membrane of the dermis. The hypodermal edge receptor organ extends from the ventral nasal barbel to the oral barbel. A mechanoreceptive function of the different receptor types is discussed. The innervation pattern of the barbel is similar to the innervation of the mammalian sinus hair. In this context, the barbel is a highly differentiated receptor organ able to explore the nearest surroundings with high stereognostic perception. The ganglion cells of the skin seem to represent a part of the peripheral autonomic nervous system, which is involved in the control of secretion mechanisms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318754
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  • 40
    Digitale Medien
    Digitale Medien
    Morphology and distribution of Müller cells in the retina of the toad Bufo marinus (1993)
    Springer
    Cell & tissue research 272 (1993), S. 183-192 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Retina ; Müller cells ; Neuron-specific enolase ; Immunocytochemistry ; Quantitative analysis ; Ultrastructure ; Bufo marinus (Anura)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract We have previously shown that an antibody against neuron-specific enolase (NSE) selectively labels Müller cells (MCs) in the anuran retina (Wilhelm et al. 1992). In the present study the light- and electron-microscopic morphology of MCs and their distribution were described in the retina of the toad, Bufo marinus, using the above antibody. The somata of MCs were located in the proximal part of the inner nuclear layer and were interconnected with each other by their processes. The MCs were uniformly distributed across the retina with an average density of 1500 cells/mm2. Processes of MCs encircled the somata of photoreceptor cells isolating them from each other by glial sheath, except for those of the double cones. Some of the photoreceptor pedicles remained free of glial sheath. Electron-microscopic observations confirmed that MC processes provide an extensive scaffolding across the neural retina. At the outer border of the ganglion cell layer these processes formed a non-continuous sheath. The MC processes traversed through the ganglion cell layer and spread beneath it between the neuronal somata and the underlying optic axons. These processes formed a continuous inner limiting membrane separating the optic fibre layer from the vitreous tissue. Neither astrocytic nor oligodendrocytic elements were found in the optic fibre layer. The significance of the uniform MC distribution and the functional implications of the observed pattern of MC scaffolding are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00323585
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  • 41
    Digitale Medien
    Digitale Medien
    Structure of the tertiary component of the myenteric plexus in the guinea-pig small intestine (1993)
    Springer
    Cell & tissue research 272 (1993), S. 509-516 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Myenteric plexus ; Enteric nervous system ; Intestine, small ; Ultrastructure ; Innervation, of intestinal muscle ; Guinea-pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The tertiary component of the myenteric plexus consists of interlacing fine nerve fibre bundles that run between its principal ganglia and connecting nerve strands. It was revealed by zinc iodide-osmium impregnation and substance P immunohistochemistry at the light-microscope level. The plexus was situated against the inner face of the longitudinal muscle and was present along the length of the small intestine at a density that did not vary markedly from proximal to distal. Nerve bundles did not appear to be present in the longitudinal muscle as judged by light microscopy, although numberous fibre bundles were encountered within the circular muscle layer. At the ultrastructural level, nerve fibre bundles of the tertiary plexus were found in grooves formed by the innermost layer of longitudinal smooth muscle cells. In the distal parts of the small intestine, some of these nerve fibre bundles occasionally penetrated the longitudinal muscle coat. Vesiculated profiles in nerve fibre bundles of the tertiary plexus contained variable proportions of small clear and large granular vesicles; they often approached to within 50–200 nm of the longitudinal smooth muscle cells. Fibroblast-like cells lay between strands of the tertiary plexus and the circular muscle but were never intercalated between nerve fibre varicosities and the longitudinal muscle. These anatomical relationships are consistent with the tertiary plexus being the major site of neurotransmission to the longitudinal muscle of the guinea-pig small intestine.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318557
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  • 42
    Digitale Medien
    Digitale Medien
    Effects of elastase on contractility and morphology of elastic tissue in isolated guinea pig papillary muscles (1993)
    Springer
    Heart and vessels 8 (1993), S. 71-78 
    Details
    ISSN: 1615-2573
    Schlagwort(e): Elastase ; Elastin ; Contractile tension ; Guinea pig papillary muscle ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Elastase (ELA) is an enzyme catalyzing the digestion of elastin, an essential constituent of elastic fibers. Using isolated guinea pig papillary muscles, we examined the effect of ELA (3 × 10−7 −3 × 10−4 g/ml) on resting tension (RT) and twitch tension (TT). The effects of ELA on elastic fibers located in the subendocardium were examined histologically. A relatively high concentration of ELA (3 × 10−4 g/ml) increased TT transiently, with progressive decreases in RT. In contrast, a relatively low concentration (3 × 10−5 g/ml) decreased both TT and RT straightforwardly. Much lower concentrations (3 × 10−6 −3 × 10−7 g/ml) did not reveal significant effects. The ELA-induced increases in TT were unaffected in the presence of atenolol (10−5 g/ml), ouabain (10−7M) or ryanodine (10−6M). ELA did not increase the maximum rate of rise of slow action potentials recorded using standard microelectrodes.ELA (3 × 10−5 g/ml) decreased the maximum TT obtained at optimal RT or Lmax, and decreased the slope of the ascending and descending limbs of the TT-RT relation curve (Frank-Starling's). Electronmicroscopic findings revealed that subendocardial elastin was mostly digested at ELA concentrations of 3 × 10−5 −3 × 10−4 g/ml. These findings suggest that the decrease of RT by ELA may be, at least in part, caused by a decomposition of the elastic fibers. On the other hand, the increase of TT by ELA could not be attributed to a release of endogenous catecholamine, an inhibition of Na+, K+-pump, a release of Ca2+ from sarcoplasmic reticulum, or an increase of slow inward current.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01744386
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  • 43
    Digitale Medien
    Digitale Medien
    Sub-cellular distribution of nitrogen compounds inAzolla andAnabaena by ESI and EELS analysis (1993)
    Springer
    Protoplasma 173 (1993), S. 158-169 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Azolla-Anabaena symbiosis ; Ultrastructure ; Nitrogen distribution ; Electron spectroscopic imaging ; Electron energy loss spectroscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The sub-cellular localization of some nitrogen compounds within the leaf cavities ofAzolla filiculoides Lam. was obtained by means of electron spectroscopic imaging (ESI) and electron energy loss spectroscopy (EELS). The analyses were performed on ultrathin unstained sections of differentAzolla leaf cavities which contain epidermal hairs,Anabaena azollae Strasb. and bacteria. Net nitrogen distributions were visualized by image analysis, and nitrogen peaks were evidenced in spectra recorded in the same areas. Different distributions of nitrogen compounds were observed within the leaf cavities along the stem, in particular inside the epidermal hairs ofAzolla and the vegetative cells and heterocysts ofA. azollae.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01379004
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  • 44
    Digitale Medien
    Digitale Medien
    Effect of cytochalasin A on actin distribution in the fission yeastSchizosaccharomyces pombe studied by fluorescent and electron microscopy (1993)
    Springer
    Protoplasma 176 (1993), S. 24-32 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Actin ; Cytoskeleton ; Schizosaccharomyces pombe ; Freeze substitution ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Actin distribution and ultrastructure of the fission yeastSchizosaccharomyces pombe treated with cytochalasin A (CA) were investigated by fluorescence microscopy using rhodamine-conjugated phalloidin (rh-ph) and freeze substitution electron microscopy. Among the cytochalasins tested, CA was most effective and at 5 μg/ ml inhibited the appearance of the actin ring at the cell equator at the stage prior to septum formation and the accumulation of actin dots at the septum-forming site both in wild-type cells and the mutantcdc 11, which is defective in septum formation at restrictive temperature. Freeze substitution electron microscopy of CA-treated cells revealed the displacement and morphological alteration of cytoplasmic vesicles and dictyosomes within 30 min and the appearance of dense bodies in the cytoplasm. A sub-population of cytoplasmic vesicles and dictyosomes were insensitive to CA and maintained their original structure. An electron less dense layer containing filamentous material was noted beneath the plasma membrane and thought to be the area of heavy actin patches stained with rh-ph at the cells ends. These results suggest that CA disrupted an actin network that normally maintains the organization of the secretory pathway involving dictyosomes and vesicles.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01378936
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  • 45
    Digitale Medien
    Digitale Medien
    Membrane coatings on the generative cell surface of freeze-substituted monocotyledon pollen (1993)
    Springer
    Protoplasma 176 (1993), S. 84-88 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Pollen (high-pressure freezing) ; Freeze-substitution ; Generative cell ; Plasma membrane ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary High-pressure freezing/freeze-substitution/TEM were employed for studying plasma membrane coatings in mature pollen grains. Data are presented on 6 species belonging to 4 not closely related orders. Two sorts of coatings were observed at the cytoplasmic face of the vegetative plasma membrane bordering the generative cell: (i) A dense, uniform layer with an average thickness of 10 nm (“fluffy coating”). (ii) “Strip-shaped projections” protruding rectangularly into the vegetative cytoplasm. They are 25 to 35 nm in height and set at a constant distance of about 30 nm from each other. Their maximum length, estimated from grazing sections, is about 400 nm. This is the first description of periodically arranged plasma membrane protrusions in freeze-substituted plant cells. Both kinds of membrane coatings are species-and age-dependent features. Especially “strip-shaped projections” are frequently intimately associated with polymorphic endoplasmic reticulum surrounding the generative cell, a hitherto unreported pattern. It is presumed that “strip-shaped projections” are similar to, or even identical with, “ordered ridges” observed in freeze-fracturedPhoenix dactylifera pollen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01378942
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  • 46
    Digitale Medien
    Digitale Medien
    The generative cell and its close association with the endoplasmic reticulum of the vegetative cell in pollen ofCyrtandra pendula (Gesneriaceae) (1993)
    Springer
    Protoplasma 177 (1993), S. 73-81 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Cyrtandra pendula ; Generative cell ; Endoplasmic reticulum ; Pollen grain ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The development of the generative cell (GC) was examined in the bicellular pollen ofCyrtandra pendula. The essential stages are: (1) GC attached to the inline, (2) GC detached and spheroidal in shape, (3) GC mature and elongated. Cisternae of the endoplasmic reticulum (ER) of the vegetative cell are in close contact with the GC at all stages of development. In stages (1) and (2) the entire, slightly undulated surface of the GC is surrounded by tightly appressed, single ER tubules or short stacks. In mature pollen grains (stage 3) the shape of the GC as well as the arrangement of the surrounding ER changes conspicuously. The GC is now spindleshaped and its surface is wrinkled. An ER tubule is present in each invagination. These ER tubules form a cage-like framework around the GC. In the cytoplasm of the generative cell, 6 to 7 microtubular bundles with longitudinal orientation can be observed. They seem to be responsible for maintaining the elongate shape of the GC. During all stages of development vegetative ER cisternae are the only elements intimately associated with the GC wall. This feature indicates that the ER may contribute to the formation of the undulated outer shape of the GC. Also discussed is the possibility that energy-carrying substances are conveyed into the GC through the channels of ER.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01403401
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  • 47
    Digitale Medien
    Digitale Medien
    Microspore development inBrassica napus and the effect of high temperature on division in vivo and in vitro (1993)
    Springer
    Protoplasma 172 (1993), S. 154-165 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Brassica napus ; Cell division ; High temperature ; Microspore ; Embryogenesis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Brassica napus cv. Topas microspores isolated and cultured near the first pollen mitosis and subjected to a heat treatment develop into haploid embryos at a frequency of about 20%. In order to obtain a greater understanding of the induction process and embryogenesis, transmission electron microscopy was used to study the development of pollen from the mid-uninucleate to the bicellular microspore stage. The effect of 24 h of high temperature (32.5 °C) on microspore development was examined by heat treating microspore cultures or entire plants. Mid-uninucleate microspores contained small vacuoles. Late-uninucleate vacuolate microspores contained a large vacuole. The large vacuole of the vacuolate stage was fragmented into numerous small vacuoles in the late-uninucleate stage. The late-uninucleate stage contained an increased number of ribosomes, a pollen coat covering the exine and a laterally positioned nucleus. Prior to the first pollen mitosis the nucleus of the lateuninucleate microspore appeared to be appressed to the plasma membrane; numerous perinuclear microtubules were observed. Microspores developing into pollen divided asymmetrically to form a large vegetative cell with amyloplasts and a small generative cell without plastids. The cells were separated by a lens-shaped cell wall which later diminished. At the late-bicellular stage the generative cell was observed within the vegetative cell. Starch and lipid reserves were present in the vegetative cell and the rough endoplasmic reticulum and Golgi were abundant. The microspore isolation procedure removed the pollen coat, but did not redistribute or alter the morphology of the organelles. Microspores cultured at 25 °C for 24 h resembled late-bicellular microspores except more starch and a thicker intine were present. A more equal division of microspores occurred during the 24 h heat treatment (32.5 °C) of the entire plant or of cultures. A planar wall separated the cells of the bicellular microspores. Both daughter cells contained plastids and the nuclei were of similar size. Cultured embryogenie microspores contained electron-dense deposits at the plasma membrane/cell wall interface, vesicle-like structures in the cell walls and organelle-free regions in the cytoplasm. The results are related to embryogenesis and a possible mechanism of induction is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01379373
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  • 48
    Digitale Medien
    Digitale Medien
    Early events in division of the generative cell ofOrnithogalum virens (1993)
    Springer
    Protoplasma 172 (1993), S. 77-83 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Ornithogalum virens ; Generative cell ; Mitosis ; Pollen ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Ornithogalum virens is a bicellular pollen species. In mature pollen, the generative nucleus is at advanced prophase. Mitosis of the generative cell is resumed just after pollen rehydration and prometaphase occurs within 10 min of germination. Prometaphase is manifested by nuclear envelope breakdown and the appearance of spindle microtubules in the nucleoplasm region. At this stage the number of cytoplasmic microtubules located in the generative cell periphery appears to decrease. Endoplasmic reticulum-like cisternae originating from the nuclear envelope tend to be spaced around the chromosomes, outside the area of the forming mitotic spindle. Some also begin to penetrate the spindle area. The results are discussed in terms of the generative cell cycle in bicellular pollen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01379365
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  • 49
    Digitale Medien
    Digitale Medien
    Ultrastructure of transfer cells in spontaneous nodules of alfalfa (Medicago sativa) (1993)
    Springer
    Protoplasma 172 (1993), S. 64-76 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Alfalfa ; Spontaneous nodules ; Development ; Rhizobium meliloti ; Transfer cells ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Spontaneous nodules were formed on the primary roots of alfalfa plants in the absence ofRhizobium. Histologically, these white single-to-multilobed structures showed nodule meristems, cortex, endodermis, central zone, and vascular strands. Nodules were devoid of bacteria and infection threads. Instead, the larger cells were completely filled with many starch grains while smaller cells had very few or none. Xylem parenchyma and phloem companion cells exhibited long, filiform and branched wall ingrowths. The characteristic features of both types of transfer cells were polarity of wall ingrowths, high cytoplasmic density, numerous mitochondria, abundant ribosomes, well-developed nucleus and nucleolus, and vesicles originated from rough endoplasmic reticulum. These results were compared with normal nodules induced byRhizobium. Our results suggest that xylem parenchyma and phloem companion transfer cells are active and probably involved in the short distance transport of solutes in and out of spontaneous nodules. Since younger nodules showed short, papillate, and unbranched wall ingrowths, and older tissue showed elongated, filiform and branched wall ingrowths, the development of wall ingrowths seemed to be gradual rather then abrupt. The occurrence of both type-A and -B wall ingrowths suggests that phloem companion transfer cells may be active in loading and unloading of sieve elements. Since there were no symbiotic bacteria and thus no fixed nitrogen, it is tempting to speculate that xylem parenchyma transfer cells may be re-transporting accumulated carbon from starch grains to the rest of the plant body by loading xylem vessels. Fusion of ER-originated vesicles with wall ingrowth membrane indicated the involvement of ER in the membrane formation for elongating wall ingrowths. Since transfer cells were a characteristic feature of both spontaneous andRhizobium-induced nodules, their occurrence and development is controlled by the genetic make-up of alfalfa plant and not by a physiological source or sink emanating from symbiotic bacteria.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01379364
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  • 50
    Digitale Medien
    Digitale Medien
    The effects of abscisic acid on the maturation ofBrassica napus somatic embryos (1993)
    Springer
    Protoplasma 174 (1993), S. 147-157 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Abscisic acid ; Brassica napus ; Embryo maturation ; Reserves metabolism ; Somatic embryos ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A comparison of embryos, cultured for increasing periods of time with and without abscisic acid (ABA), was undertaken to investigate, at the ultrastructural level, the influence of this growth regulator on the maturation of rapeseed (Brassica napus) somatic embryos. In the absence of ABA, the embryos germinated precociously while lipid bodies (LB), which were not numerous, soon degraded, as revealed by a depletion process associated with the appearance of morphologically mature glyoxysomes and an increase in the number of mitochondria. Moreover, a lack of protein bodies indicated that storage protein accumulation was not initiated under these conditions. On the contrary, the addition of ABA (10 μM) induced marked modification of embryo metabolism. Indeed, ABA completely prevented precocious embryo germination and inhibited lipid reserve catabolism. Moreover, the formation of small vacuoles and proliferation of rough endoplasmic reticulum in their vicinity suggested the onset of storage protein accumulation. After 15 days in the presence of ABA, the embryos contained abundant lipid and protein bodies. Nevertheless, these somatic embryos were not exactly the same as their mature zygotic counterparts since differences were found in chloroplasts, amyloplasts, and nuclear structures. These observations suggest that additional factors might be required to obtain fully mature somatic embryos.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01379047
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  • 51
    Digitale Medien
    Digitale Medien
    Skeletal muscle damage during tourniquet-induced ischaemia (1993)
    Springer
    European journal of applied physiology 67 (1993), S. 342-347 
    Details
    ISSN: 1439-6327
    Schlagwort(e): Tourniquet ; Ischaemia ; Skeletal muscle ; Damage ; Lysosomes ; Oedema ; Capillaries ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Muscle biopsies from the vastus lateralis muscle of patients who had undergone anterior cruciate ligament surgery under conditions of tourniquet-induced ischaemia were examined under the electron microscope at different periods of time up to 90 min of ischaemia. The severity of the alterations in ultrastructure appeared to depend on the period of ischaemia. The pathological changes consisted of accumulation of lysosomes, persistent intrafibre oedema, and some extracellular oedema. Signs of fibre necrosis were found after 90 min of ischaemia. Capillary ultrastructure was only altered with regard to some swelling of the endothelium and marked thickening of the basement membrane. It was concluded that skeletal muscle could be severely affected even during relatively short periods of ischaemia, which might facilitate the development of muscle atrophy during immobilization after orthopaedic surgery.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00357633
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  • 52
    Digitale Medien
    Digitale Medien
    Ultrastructural changes in salivary glands after different adrenergic and cholinergic stimulations (1993)
    Springer
    European archives of oto-rhino-laryngology and head & neck 250 (1993), S. 33-39 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Rat salivary gland ; Ultrastructure ; Adrenergic stimulation ; Cholinergic stimulation ; Sialagogues
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We have compared four different sialagogues and their degranulating effect on serous and mucous cells, and their long-term effects. From this and earlier experiments, even within the groups of α- and β-adrenergic agents used, the effects varied on the serous and mucous cells. Previous studies have shown that cyclocytidine effectively degranulates serous cells without signs of cellular damage, while carbachol predominantly affects mucous acinar cells but gives early rise to permanent gland damage. Noradrenaline affects both serous and mucous cells, predominantly affecting serous cells with initial mitochondrial damage. Clonidine partially depletes both serous and mucous cells of their granules, producing permanent cellular damage. One month after a single injection of cyclocytidine the early findings described had disappeared. Carbachol showed permanent damage to salivary gland parenchyma, and both noradrenaline and clonidine demonstrated a long-term effect on acinar mucinous cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00176946
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  • 53
    Digitale Medien
    Digitale Medien
    Ultrastructural observation on hepatocellular carcinoma (1993)
    Springer
    Medical molecular morphology 26 (1993), S. 19-28 
    Details
    ISSN: 1860-1499
    Schlagwort(e): Hepatocellular carcinoma ; Tumor grade ; Ultrastructure ; Morphometry ; Cell organelles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In 31 cases of hepatocellular carcinoma, electron microscopic observation and morphometry on the cell organelles were carried out to evaluate the usefulness of electron microscopy for the diagnosis of well differentiated hepatocellular carcinoma. The cell organelles in well differentiated tumor cells were very similar to those in normal hepatocytes or hepatocytes with liver cirrhosis (LC). We found that in poorly differentiated tumor cells, the nuclear area, N/C ratio, nucleolar area, the amount of dispersed chromatin, and the number of free ribosomes had increased, but the cellular area, degree of nuclear roundness, and mitochondrial area had decreased. These results seem to indicate that electron microscopy is not as useful as light microscopy in the diagnosis of well differentiated hepatocellular carcinoma, but is useful in the study of poorly differentiated tumor cells, which indicated that the cell proliferation through mitoses was activated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02348832
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  • 54
    Digitale Medien
    Digitale Medien
    Ultrastructural effects of immobilization on rat muscle spindles (1993)
    Springer
    Medical molecular morphology 26 (1993), S. 65-75 
    Details
    ISSN: 1860-1499
    Schlagwort(e): Ultrastructure ; Rats ; Muscle spindles ; Immobilization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The ultrastructure of rat muscle spindles was examined after the anterior tibial muscles had been immobilized in a plaster cast. There was an increase in the number of collagen fibrils and external laminae around the outer capsules and in the intracapsular space 2 weeks after immobilization. The changes in the intrafusal muscle fibers within 4 weeks included disorientation of myofilaments. After 6 weeks, Z bands had become disarranged, and there was vacuolar degeneration of the sarcoplasmic reticulum in some fibers. Myelin sheaths of many of the myelinated nerve fibers (especially the thick ones, which were probably sensory nerve fibers) had degenerated within 2 weeks. These results indicate that immobilization of skeletal muscles affects not only extrafusal muscle fibers but also the structure of the muscle spindle.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02348837
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  • 55
    Digitale Medien
    Digitale Medien
    Scanning electron microscopic study of the adhesion of a human megakaryocytic leukemia cell line (CMK11-5) (1993)
    Springer
    Medical molecular morphology 26 (1993), S. 81-87 
    Details
    ISSN: 1860-1499
    Schlagwort(e): Human megakaryocytic leukemia cell line ; Adhesion ; Glycoprotein Ib ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract To characterize the CMK11-5 subclone of a human megakaryocytic leukemia cell line (CMK), an ultrastructural study on adhesion was performed. The CMK11-5 cells showed irreversible attachment to rabbit aortic subendothelium accompanied by several morphological changes such as flattening and the spreading out of pseudopodia. These morphological changes are similar to those observed in normal platelets during attachment. The attachment of CMK11-5 cells to rabbit aortic subendothelium indicates that human megakaryocytes may possess an adhesion function like that of platelets. The CMK cell line and its CMK11-5 subclone with megakaryocytic properties appear to be useful for studying the function of megakaryocytes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02348032
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  • 56
    Digitale Medien
    Digitale Medien
    Ultrastructural localization ofcalcium dependent adenosine triphosphatase (ATPase) in the myocardium of endotoxin-administered rats (1993)
    Springer
    Medical molecular morphology 26 (1993), S. 151-155 
    Details
    ISSN: 1860-1499
    Schlagwort(e): Endotoxemia ; Enzyme histochemistry ; Ca++-ATPase ; Ultrastructure ; Myocardium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Enzyme-cytochemical studies were performed to clarify the pathogenesis of myocardial damage in endotoxemia. The reaction product of Ca++-ATPase was localized on the pinocytotic vesicles and plasma membrane of endothelial cells of capillaries and sarcolemma, sarcoplasmic reticulum and mitochondria of cardiomyocytes in control rats. However, the enzyme reaction product was reduced in amount and irregularly distributed on the plasma membrane, and on the increased number of pinocytotic vesicles of the endothelial cells of capillaries and the sarcolemma and sarcoplasmic reticulum of edematous cardiomyocytes after endotoxin injection. It is concluded that endotoxin induces structural changes and decreased activity in Ca++-ATPase in the vascular endothelium and myocytes of the heart.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02348041
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  • 57
    Digitale Medien
    Digitale Medien
    Ultrastructure of experimental candidial lesions in the rabbit esophagus (1993)
    Springer
    Medical molecular morphology 26 (1993), S. 215-217 
    Details
    ISSN: 1860-1499
    Schlagwort(e): Ultrastructure ; Esophagus ; Candida albicans ; Candidial lesion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Although the esophagus is the most frequent site ofCandida infections in the gastrointestinal tract, and many clinical studies about it have been reported, little attention has been directed toward experimental candidiasis of the esophagus, especially with regard to its ultrastructure. Using transmission electron microscopy, this study was performed to clarify the ultrastructure of experimental lesions, obtained from five New Zealand white male rabbits which were given a suspension ofCandida albicans cells (107/ml) for 13 days. The results showed that the lesions consisted of exfoliating, squamous epithelial cells with mycelial elements ofCandida albicans cells penetrating through them, and that a widened intercellular space between individual cells in the area of candidial invasion seems to be a characteristic finding of candidial infection.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02348004
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  • 58
    Digitale Medien
    Digitale Medien
    Salmon roe-like amyloid deposition in a prolactinoma: a case report (1993)
    Springer
    Brain tumor pathology 20 (1993), S. 89-92 
    Details
    ISSN: 1861-387X
    Schlagwort(e): Amyloid ; Magnetic resonance imaging ; Pituitary adenoma ; Prolactinoma ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract An unusual case of prolactin-producing adenoma with extensive amyloid deposition is reported to clarify its radiological, intraoperative, and light- and electron-microscopic findings. A 41-year-old female patient complained of amenorrhea persisting for 20 years. Magnetic resonance imaging (MRI) revealed a pituitary adenoma, which included low-intensity spots on T1- and T2-weighted images. Intraoperative examination found multiple small, yellowish, spherical masses resembling salmon roe within the adenoma. Light and electron microscopy revealed the presence of immunoreactive cells for prolactin intermingled with concentric lamellar bodies of radially arranged amyloid fibrils originating from the endoplasmic reticulum in prolactinoma cells. The extracellular lamellar amyloid deposits were apparently due to degradation of prolactin-producing cells, but the reason for the production and radially arranged accumulation of amyloid remains to be identified.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02483453
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  • 59
    Digitale Medien
    Digitale Medien
    A fourth ventricle atypical teratoid/rhabdoid tumor in an infant (1993)
    Springer
    Brain tumor pathology 20 (1993), S. 47-52 
    Details
    ISSN: 1861-387X
    Schlagwort(e): Atypical teratoid/rhabdoid tumor ; Fourth ventricle ; Immunohistochemistry ; Ultrastructure ; Basal lamina
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Atypical teratoid/rhabdoid tumor (AT/RT), a recently established central nervous system tumor entity, occurs in children and is more malignant than medulloblastoma/primitive neuroectodermal tumors (PNET). We report here a case of AT/RT in a male infant who was 9 months old at the time of diagnosis. Magnetic resonance imaging revealed that the tumor occupied the fourth ventricle, and at surgery it was found to adhere to the floor of the fourth ventricle. After subtotal removal of the tumor mass, chemotherapy and radiotherapy were performed, but the patient died about 8 months after the diagnosis following rapid regrowth of the residual tumor. Light-microscopically, the tumor was composed mainly of nests of rhabdoid cells with fields of PNET. Occasional mesenchymal and epithelial fields were also evident. Immunohistochemically, these rhabdoid cells were positive for vimentin, epithelial membrane antigen, smooth-muscle actin, cytokeratin, and S-100 protein, and less frequently for glial fibrillary acidic protein. Electron-microscopically, the typical rhabdoid cells contained whorled bundles of intermediate filaments in their cytoplasm. Occasionally, such rhabdoid cells were covered partially by basal lamina at their stromal interface. These findings are typical of AT/RT. Although it is well known that AT/RT often arises in the posterior fossa, detailed reports of cases affecting the fourth ventricle are rare. In this case, the ultrastructural relationship between rhabdoid cells and the basal lamina, which has not so far been described in AT/RT, was of great interest when the nature of the rhabdoid cells was considered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02483446
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  • 60
    Digitale Medien
    Digitale Medien
    Immunocytochemistry of ambiguous cells in adult and embryonic dwarf (dw) mouse pituitaries (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 236 (1993), S. 671-678 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Dwarf Mouse ; Pituitary Gland ; Embryo ; Immunocytochemistry ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: In the pars distalis of the pituitary gland in adult and embryonic dwarf (dw/dw) mutant mice, ambiguous cells exhibiting ultrastructural features common to growth hormone (GH) cells and prolactin (Prl) cells were analyzed by means of colloidal gold ultrastructural immunocytochemistry in order to define the functional nature of these peculiar cells. Adult and 18-day embryonic pituitaries from normal (+/+; dw/+) and dwarf (dw/dw) mice were processed with antibodies to GH, Prl, TSH (thyroid-stimulating hormone), ACTH (adrenocorticotropic hormone), LH (luteinizing hormone), FSH (follicle-stimulating hormone), and HCG (chorionic gonadotropic hormone). In the adult and embryonic dwarf pituitaries, the ambiguous cells reacted negatively to all of the antibodies except for anti-ACTH, which labeled them well. In addition, the ACTH-positive cells showed a much wider variety of shapes and granule size and distribution, as compared with normal adults. In the embryos, this variability in ACTH cell morphology occurred not only in dwarf embryos, but in their normal counterparts as well. The results thus suggest that adult dwarf pituitaries may retain an embryonic or incompletely differentiated form of ACTH cells. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092360411
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  • 61
    Digitale Medien
    Digitale Medien
    Ultrastructure of the human anogenital “sweat” gland (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 235 (1993), S. 583-590 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Skin ; Vulva ; Sweat glands ; Histology ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A newly described type of cutaneous gland occurring in the human anogenital region was investigated in specimens from the vulva by electron microscopy. This gland, which is characterized by a long excretory duct opening at the skin surface, by a wide coiled secretory part with multiple lateral extensions in the form of diverticula and branches lined by a two-layered pseudostratified of myoepithelium, and by a luminal layer of tall columnar cells with conspicuous “snouts”, could not be categorized as an eccrine, apocrine, or mammary gland. Electron microscopy confirmed its separate position by showing that the luminal layer of secretory cells with prominent cytoplasmic caps had elaborately folded lateral membranes, occasional canaliculi, and a large number of uniform electron-lucent to moderately electron-dense secretory granules as part of a probable merocrine secretion. The excetory duct showed a poorly developed cuticular border. This combination of ultra-structural features is alien to the other tubular cutaneous glands. The function of this anogenital “sweat” gland remains obscure, but the presence of these granules suggests a secretion product that is different from that of other cutaneous glands. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092350411
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  • 62
    Digitale Medien
    Digitale Medien
    Chronology of peroxidase activity in the developing rat parotid gland (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 235 (1993), S. 611-621 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Peroxidase ; Parotid gland ; Salivary gland ; Rat ; Growth and development ; Biochemistry ; Cytochemistry ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The course of development of salivary peroxidase, an enzyme that has an important role in oral defense mechanisms, has been well documented in rat submandibular glands. However, the only report on salivary peroxidase activity in the other major salivary glands of the rat has been a cytochemical study of the adult parotid gland. In the present investigation, the accumulation of salivary peroxidase activity in developing parotid glands of rats was followed both biochemically and cytochemically. Specific activity (units per mg protein) attributable to salivary peroxidase began at 1 day after birth, then rose rapidly but unevenly, with peaks at 21 and 70 days, and no difference between the sexes at any age. Activity per gland increased progressively to 42 days in both sexes and was significantly higher in males at 70 days. The cytochemical observations on peroxidase activity localized to the rough endoplasmic reticulum and secretory granules of the developing acini were well correlated with the biochemical findings. Peroxidase-negative cells occurred in immature acini at 1 and 7 days, but only in the intercalated ducts thereafter. This observation suggests that the acini are a source of some of the ductal cells, at least during early postnatal development. The developmental pattern of specific activity differed from those of other rat parotid secretory enzymes, indicating that control of their synthesis during development is noncoordinate. The patterns of specific activity of the parotid and submandibular glands were complementary, suggesting that their combined secretions may supply biologically significant peroxidase activity to the oral cavities of rats throughout postnatal development. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092350414
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  • 63
    Digitale Medien
    Digitale Medien
    Ultrastructure of lipid-containing cells of the anterior pituitary gland of the domestic chicken, Gallus domesticus (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 237 (1993), S. 506-511 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Anterior pituitary ; Domestic chicken ; Lipid cells ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A combination of light and electron microscopy techniques was applied to characterize a luteinizing hormone (LH)-gonadotroph-like cell in the anterior pituitary gland of the adult domestic chicken. This cell type (mean ± sem, 91 ± 8 μm2) was larger than typical LH-gonadotrophs (71 ± 5 μm2, P 〈 0.01) and seen in pituitary glands from adult males but not those from adult females of the same age. The ultrastructural features of these cells were similar to typical LH-gnoadotrophs in the same section, except for the presence of large (1,126 ± 77 nm diameter), round, or polymorphic electron-dense inclusions (14 ± 3 per cell) in the cisternae of the endoplasmic reticulum. When resin sections of anterior pituitary gland were stained with the vapours from the fixative osmium tetroxide and a solution of potassium ferricyanide, inclusions were found that appeared to be lipid in nature and were circumscribed by the cisternal membranes of the endoplasmic reticulum. These lipid inclusions were associated occasionally with acid phosphatase and lysosome-like bodies. The cellular pigment, lipofuscin, considered to be a marker of aging, was absent from the anterior pituitary glands from these adult chickens. These observations suggest that the appearance of lipid in LH-gonadotrophs is unlikely to be age-related and an alternative explanation is discussed in relation to a sex difference in the LH response of adult chickens to gonadotrophin-releasing hormone (GnRH). © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092370410
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  • 64
    Digitale Medien
    Digitale Medien
    Ultrastructural characteristics of primordial germ cells in the quail embryo (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 236 (1993), S. 547-552 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Primordial germ cells ; Ultrastructure ; Nucleolus ; Quail embryo ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: An avian species, the quail has become a desirable animal model in experimental embryology and reproductive biology. To understand the ultrastructural characteristics of primordial germ cells (PGC) of this species, we studied PGC in the Japanese quail (Coturnix coturnix japonica) embryo at various developmental stages from their appearance in the germinal crescent through migration to settlement in the gonadal ridges by means of electron microscopy. The results were compared with those of another well-known avian species, the chick. Several ultrastructural characteristics of quail PGC not described previously in chick PGC were observed as follows: (1) No glycogen particles were detected in the cytoplasm at any stage examined. (2) Electron-dense and membrane-bounded granules were found in the PGC cytoplasm during the sexually indifferent gonadal stages. (3) Quail PGC were characterized by a prominent nucleolus associated with condensed chromatin (heterochromatin), and the developmental changes of the nucleus, were noted; the nucleolus initially appeared as a compact mass at the germinal crescent stage and became dispersed at later stages during the colonization of the gonadal ridges. These findings suggest several physiological and functional differences in the cell cycle between these two avian species. This is the first report describing detailed ultrastructural characteristics of PGC in the quail embryo. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092360314
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  • 65
    Digitale Medien
    Digitale Medien
    Cytologic structures unique to deiters cells of the cochlea (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 237 (1993), S. 421-430 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Organ of Corti ; Ultrastructure ; Cytoskeleton ; Gerbil ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Deiters cells in the gerbil cochlea disclosed unusual ultrastructural features. A sharp transition zone separated the cell body underlying outer hair cells into an upper compartment with numerous organelles and a lower part devoid of structures other than the microtubule stalk. Deiters cells exhibited a unique structure, the rosette complex, which consisted of a core of densely fibrillar trabeculae, enclosed in a filamentous meshwork and surrounded by tubulocisternal endoplasmic reticulum. The dense trabeculae radiated in columns downward from an apical translucent area toward a lucent zone around the nucleus. They also spread to the medial plasmalemma enveloping nerves and upward into the base of the phalanx. Frequent, small Golgi complexes bordered the tubular reticulum. The distinctive mitochondria of Deiters cells frequently paralleled the plasmalemma, revealed an elongated, often arched profile, and contained sparse, longitudinally aligned cristae. The stalk, composed of characteristic microtubule bundles resembling those in pillar cells, ascended from basal to apical plasmalemma of the cell body and into the phalanx and reticular lamina as previously described. The stalk appeared also to ramify into smaller microtubule bundles in apical cytosol penetrating the rosette complex. Nuclei in Deiters cells differed from those in hair cells in their location high in the cell and in showing chromatin dispersion indicative of more active protein synthesis. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092370316
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  • 66
    Digitale Medien
    Digitale Medien
    Ultrastructural changes in the efferent duct and epididymis of men with obstructive infertility (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 237 (1993), S. 199-207 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Epididymis ; Ultrastructure ; Obstructive infertility ; Vasoepididymostomy ; Spermatozoa ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Ultrastructural changes in the efferent duct and in different regions of the epididymis in men with obstructive azoospermia were compared with corresponding tissues collected from men of proven fertility who underwent castration due to malignancy of the prostate. Major degenerative changes were seen in the efferent duct and the caput epididymidis of men with obstruction at the caput epididymidis which may have been induced by fluid pressure due to defective absorption of testicular fluid in the caput epididymidis. These degenerative changes included decrease in tubular and lumen diameter of the caput and the cauda epididymides, decrease in height of the stereocilia, reduction in-rough endoplasmic reticulum and Golgi material, and presence of lipofuscin and osmiophilic dense bodies. The degenerative changes were less when the site of obstruction was in the cauda epididymidis since fluid reabsorption would continue to take place normally in the caput epididymidis. In men who had undergone vasoepididymostomy (VEA), the ejaculated spermatozoa showed a high percentage of morphological abnormalities which may have occurred due to adverse effects of long-term obstruction on spermatogenesis. © 1993 Wiley-Liss Inc.
    Zusätzliches Material: 19 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092370207
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  • 67
    Digitale Medien
    Digitale Medien
    Posterior pituitary of the newborn marsupial possum, Trichosurus vulpecula (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 237 (1993), S. 228-235 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Posterior pituitary ; Marsupial ; Trichosurus vulpecula newborn ; Ultrastructure ; Immunocytochemistry ; Mestocin ; Vasopressin ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The fetal anterior pituitary-adrenal axis is thought to be involved in the initiation of birth in both eutherian and marsupial mammals. Little is known about the structure and function of the posterior pituitary at birth in the marsupial. Immunocytochemistry, high pressure liquid chromatography, and radioimmunoassay were used to identify vasopressin and mesotocin in the posterior pituitary of a newborn marsupial, the brushtail possum, Trichosurus vulpecula. The concentrations of vasopressin and mesotocin in the head of the newborn possum were 0.34 and 0.28 ng, respectively. The concentration of vasopressin was always greater than that of mesotocin, and the amounts of neuropeptides present in the head increased as the possum developed. © 1993 Wiley-Liss Inc.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092370210
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  • 68
    Digitale Medien
    Digitale Medien
    Immunoelectron microscope localization of snRNP, hnRNP, and ribosomal proteins in mouse spermatogenesis (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 35 (1993), S. 261-271 
    Details
    ISSN: 1040-452X
    Schlagwort(e): Immunocytochemistry ; Ultrastructure ; Perichromatin granules ; Interchromatin granules ; Mouse spermatids ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We have studied the ultrastructural distribution of heterogeneous nuclear ribonucleoproteins (hnRNPs), small nuclear ribonucleoproteins (snRNPs), and ribosomal proteins during mouse spermatogenesis and spermiogenesis by means of specific antibodies and immunocytochemistry.All the above components were detectable from primary spermatocytes until the spermatid elongation phase, when the RNA synthetic activity is known to cease. Ribosomal protein (P1/P2 and L7) labeling disappeared as early as during the acrosome phase, and nucleoli were no longer labeled even during the cap phase. The nucleoplasmic structures labeled with the different anti-nucleoplasmic RNP immunoprobes corresponded, until the acrosome phase, to those previously observed as targets of the same antibodies in the nucleoplasm of somatic cell nuclei. Clusters of interchromatin granules of spermatocyte and early spermatid nuclei exhibit some labeling for hnRNP when compared with nuclei of Sertoli cells or previously analyzed liver or tissue culture cells, where these structural constituents usually remain weakly labeled or unlabeled.In spermatids in step 10, another type of nuclear granule, resembling perichromatin granules, but occurring in aggregates, can be observed. These structural constituents were labeled with antibodies recognizing nucleoplasmic snRNP antigens and therefore suggesting a non-nucleolar origin of these granules.Finally, we have observed nucleoplasmic areas of fibrogranular material, occurring only in primary spermatocytes. These components were labeled with anti-ribosomal protein antibodies but did not contain either hnRNPs or snRNPs. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrd.1080350308
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  • 69
    Digitale Medien
    Digitale Medien
    Comparison of hexamethyldisilazane (HMDS), Peldri II, and critical-point drying methods for scanning electron microscopy of biological specimens (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 26 (1993), S. 489-495 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Ultrastructure ; Tissue preparation ; Animal ; Plant ; Leaf ; Cuticle ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Three different drying methods, critical-point drying (CPD), Peldri II, and hexamethyldisilazane (HMDS), were compared using representative animal( rat kidney, trachea, duodenum, lung, and red blood cells) and plant( leaves from ten species of monocotyledons and dicotyledons) specimens. All three drying methods produced identical results with animal specimens. Plant specimens showed signs of shrinkage regardless of which drying method was employed. The order of preservation quality from best to worst for leaves was CPD 〉 Peldri II 〉 HMDS, with the CPD method providing substantially better results in all but one case. Postfixation of leaves with osmium tetroxide resulted in poorer preservation in all instances. Peldri II caused complete extraction of leaf cuticular wax, while both both CPD and HMDS showed minimal extraction compared with samples air dried directly from acetone. These results indicate that HMDS provides a time-saving and inexpensive alternative to CPD for animal specimens. Plant specimens, particularly those containing cells with large central vacuoles, are adequately preserved only with the CPD method. In addition, postfixation with osmium should be avoided when processing plant specimens for scanning electron microscopy. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070260603
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  • 70
    Digitale Medien
    Digitale Medien
    Electron microscopic immunocytochemistry of glutamate-containing nerve fibers in the taste bud of mudpuppy (Necturus maculosus) (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 26 (1993), S. 225-230 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Gustation ; Neurotransmitters ; Ultrastructure ; Amphibia ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The presence of glutamate immunoreactivity (glu-IR) in the nerve fibers of the mudpuppy taste bud was investigated by electron microscopy. Pre-embedding staining with avidinbiotin-peroxidase complex (ABC) and post-embedding staining with 5 mm colloid gold conjugates were used separately to identify immuno-stained structures. We have found the following: 1) the majority of the nerve fibers innervating the mudpuppy taste bud are unmyelinated; 2) about 85% of nerve fibers located at the base of the taste bud and about 60% of the nerve fibers located between the taste cells show glu-IR by pre-embedding staining; 3) there is a preferential staining of the glu-IR in the nerve fibers of the mudpuppy taste bud; and 4) the distribution of the colloidal gold particles in the nerve fibers is 1.5 to 2 times denser than that of the staining in the connective tissue background or cellular profiles of taste cells. From the distribution and pattern of the nerve fibers obtained in the thick and thin sections, we conclude that the mudpuppy taste bud is innervated by glutamate-containing unmyelinated nerve fibers. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070260305
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  • 71
    Digitale Medien
    Digitale Medien
    Process of nuclear envelope reduction in spermiogenesis of a mosquito, Culex tigripes (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 34 (1993), S. 416-419 
    Details
    ISSN: 1040-452X
    Schlagwort(e): Spermatid ; Ultrastructure ; Diptera ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: When the Culex tigripes spermatid begins to elongate, the nucleus exhibits on its surface invaginations of the nuclear envelope. These invaginations have a uniform diameter of 0.3 μm. They separate from the envelope of the nucleus and form spherical intranuclear vesicles. In the old spermatids these vesicles are imprisoned in the condensed chromatin. The spermatozoon also possesses these vesicles which are then ovoid in shape. This process of vesiculation permits the diminution of the surface of the nucleus when it decreases in volume during spermiogenesis. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrd.1080340410
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  • 72
    Digitale Medien
    Digitale Medien
    Electron microscopy of intracellularly labeled neurons in the hippocampal slice preparation (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993), S. 67-84 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Intracellular labeling ; Horseradish peroxidase ; Lucifer Yellow ; Biocytin ; Neurobiotin ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: We have assessed the properties of three intracellular markers, horseradish peroxidase, biocytin/Neurobiotin, and Lucifer Yellow, and have compared their usefulness as neuronal markers for light and electron microscopic visualization. Neurons in the acute slice preparation of rat hippocampus were filled with one of these markers, and the marker was converted to an optical and electron-dense reaction product. Dimethylsulfoxide (DMSO) greatly facilitated penetration of recognition reagents while preserving membrane integrity. The markers were compared with respect to injection parameters, mobility and recognition, stability and visibility, and ultrastructural clarity. Horseradish peroxidase (HRP)-labeled neurons, recognized histochemically with diaminobenzedine (DAB), were easily visualized by the density of the DAB reaction product; however, the electron density was often so great as to obscure ultrastructural details. Biocytin (BC)-/Neurobiotin (NB)-labeled neurons were recognized by avidin-HRP, followed by histochemical localization of HRP with DAB. The optically dense reaction product gave complete visualization of the soma and processes at the light microscopic level. The electron density was homogeneously distributed throughout the cell, so that ultrastructural features were easily identified. Lucifer Yellow (LY), a fluorescent marker, was converted to an optical and electron-dense reaction product via immunocytochemical staining with a rabbit anti-LY antibody, followed by goat anti-rabbit IgG-HRP and DAB histochemical localization. Similar to BC/NB, the reaction product was evenly dispersed, providing good light microscopic and ultrastructural clarity. Under our experimental conditions, BC/NB and LY were superior markers that could be used routinely to label neurons, and give excellent visualization not only at the light but also at the electron microscopic level. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 32 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070240107
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  • 73
    Digitale Medien
    Digitale Medien
    Characteristics of uterine aging (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 25 (1993), S. 148-168 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Uterus ; Endometrium ; Decidua ; Collagen ; Ultrastructure ; Rodent ; Human ; Review ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Uterine aging is in part responsible for a decline in fecundity which begins in middle age in most mammals. Characteristics of uteri from a variety of animals in middle age and old age are reviewed and the factors which may be responsible for this decline discussed. These include age-related changes in the hypothalamus, pituitary, and ovaries; loss of number or function of steroid hormone receptors; morphological changes in the uterine epithelium; the accumulation of collagen fibrils in the uterine stroma; and loss or impairment of the decidual response. The ultra-structural morphology of uterine epithelial, stromal, and decidual tissue from 4 month old and 18 month old Fischer 344 rats is presented and compared. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 23 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070250207
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  • 74
    Digitale Medien
    Digitale Medien
    Cellular relations in mouse circumvallate taste buds (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 26 (1993), S. 209-224 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Cell types ; Ultrastructure ; Mammalian ; Ninth nerve ; Dense-cored vesicles ; Papilla ; Rabbit ; Trophic ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The fine structure of the taste buds of circumvallate papillae of two strains of mice was studied by electron microscopy. Mice anesthetized with ketamine were perfused through the heart with a double aldehyde mixture in cacodylate buffer and the tissues embedded in Epon. Semi-serial sections were employed. The morphology and relationships of cell types are consistent with the majority of descriptions of mammalian taste buds served by the ninth cranial nerve. Cells of type II are particularly well documented, as the stages in their origin, maturation and degeneration could be followed. Significant differences, however, relate to cell type I. These cells contain large dense-cored granules, contrasted with the more irregular and somewhat larger dark granules of the type I cells in the rabbit. These granules do not produce a dense homogenous product for the pore, as seen in the rabbit. Rather the pore substance consists of small, empty vesicles in a diffuse dark matrix. These granules are only moderately larger than the dense-cored vesicles of the type III cells. All features of the type III cell were demonstrated, although no instance of a complete cell was seen in any section. No significant differences were noted between the two strains of mice. Intimate proximity of a nerve to a cell nucleolus, suggestive of a trophic pathway, is illustrated. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070260304
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  • 75
    Digitale Medien
    Digitale Medien
    A sertoli-leydig cell tumor and pregnancy (1983)
    Springer
    Archives of gynecology and obstetrics 233 (1983), S. 295-308 
    Details
    ISSN: 1432-0711
    Schlagwort(e): Sertoli-Leydig cell tumor ; Pregnancy ; Catheterization ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An extremely rare case of a conception occurring in a 26-year-old patient with a small virilizing Sertoli-Leydig cell tumor (diameter: 0.6 cm), bilateral polycystic ovaries and non-tumorous adrenal hyperandrogenism is presented. Prepregnancy findings included hirsutism, clitoromegaly, secondary amenorrhea, and elevated peripheral plasma testosterone (T; 5.7 ng/ml). Extensive basal steroid screening, dynamic function tests, conventional radiologic procedures, selective glandular vein catheterization, and laparoscopy failed to localize unequivocally the source of androgen excess, but suggested bilateral adrenal involvement. The patient conceived during the diagnostic work-up; peripheral T levels increased to 12.1 ng/ml within the first trimester. An exploratory laparotomy with left adrenalectomy, right adrenal biopsy and left ovarian wedge resection revealed an incompletely removed Sertoli-Leydig cell tumor, but normal adrenal histology. The pregnancy was terminated, a left oophorectomy and right ovarian wedge resection were performed at 14 weeks' gestation. Subsequently, peripheral androgens returned to normal, regular menses resumed, and hirsutism disappeared. Three years later the patient delivered a healthy female infant.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02133804
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  • 76
    Digitale Medien
    Digitale Medien
    Membranous lipodystrophy-like changes in ischemic necrosis of the legs (1983)
    Springer
    Virchows Archiv 399 (1983), S. 191-205 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Membranous lipodystrophy ; Fat tissue ; Ischemic necrosis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Subcutaneous fat from 3 patients with ischemic necrosis of the legs due to arteriosclerotic obstruction were examined histologically and ultrastructurally. Markedly convoluted membranocystic changes were found in all 3 cases. The light and electron microscopic findings of the membranocystic lesions are very similar to those of fat tissue changes in membranous lipodystrophy. Bone lesions and mental disturbance which suggest membranous lipodystrophy, however, were absent in these cases. It is concluded from these results that the membranocystic changes characteristic of membranous lipodystrophy can be produced by circulatory disturbance and the lesions are one of the non-specific changes of adipose tissue.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00619579
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  • 77
    Digitale Medien
    Digitale Medien
    Ultrastructure of the congenital epulis (1983)
    Springer
    Virchows Archiv 401 (1983), S. 251-260 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Congenital epulis ; Ultrastructure ; Granular cells ; Intracellular collagen fibrils
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This report presents the ultrastructural features of a congenital epulis. The granular cells of the epulis were packed with numerous membrane bound cytoplasmic granules containing particles, small vesicles, and electron-dense materials. These granules were negative in immunohistochemical reaction for CEA (DAKO PAP KIT). Cytoplasmic organelles such as mitochondria, rough surfaced endoplasmic reticulum, and Golgi apparatus, were absent. Nuclei were markedly indented. Occasionally, banded intracellular collagen fibrils were observed within the cytoplasm. Some of these fibrils were surrounded by a limiting membrane, whereas others appeared to lie free in the cytoplasm. The collagen fibrils were also seen within a deep invagination of the cell surface. There was no basal lamina around the granular cells. Sporadically, mast cells with many granules containing lamellar formations were found between the granular cells. These observations support the idea that granular cells of the congenital epulis are derived from mesenchymal cells, probably fibroblasts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00734843
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  • 78
    Digitale Medien
    Digitale Medien
    Mammosomatotroph cell adenoma of the human pituitary: a morphologic entity (1983)
    Springer
    Virchows Archiv 398 (1983), S. 277-289 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Pituitary adenoma ; Ultrastructure ; Immunocytochemistry ; Acromegaly ; Hyperprolactinemia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Nine cases of a hitherto undescribed morphologic entity, termed mammosomatotroph cell adenoma of the human pituitary, are reported. These tumors, occurring mostly in men, are invariably associated with acromegaly (or gigantism) and high-normal or slightly elevated blood prolactin levels, and it cannot be distinguished clinically from well-differentiated growth hormone cell or mixed growth hormone cell-prolactin cell adenomas. They show a slow growth rate and usually exhibit a diffuse pattern and intense cytoplasmic acidophilia by histology. The immunoperoxidase technique detects both growth hormone and prolactin within the same cells. Electron microscopy reveals monomorphous tumors with a fine structure markedly similar to that of well-differentiated, densely granulated growth hormone cell adenomas. An added feature and diagnostic marker of mammosomatotroph cell adenoma is the presence of extracellular deposits of secretory material. One tumor shows a marked abnormality of hormone packaging and storage, resulting in the cytoplasmic accumulation of pleomorphic bodies containing semicrystalline secretory material.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00583585
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  • 79
    Digitale Medien
    Digitale Medien
    Experimental autoallergic sialadenitis in mice (1983)
    Springer
    Virchows Archiv 400 (1983), S. 143-154 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Experimental autoallergic sialadenitis ; Mice ; Submandibular gland ; Histopathology ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Experimental autoallergic sialadenitis was induced in SL/Ni mice by one or two injections of syngeneic submandibular gland homogenate emulsified with adjuvant. Light microscopically, there were marked lymphoid cell infiltration in the submandibular glands with high incidence and proliferation of duct epithelia. Furthermore complete alteration of whole glandular lobules in some cases was observed. Ultrastructurally, small and medium sized lymphocytes and plasma cells constituted a major portion of the infiltrating cells, and lymphocytes were frequently observed inside the basal lamina of ductal and acinar regions, especially observed in the small ductal region. In the aggregates of infiltrating cells, the cell remnants of salivary gland epithelia were scattered. Furthermore some of the epithelial cell remnants in aggregates of infiltrating cells could be recognized as epithelial masses which were composed of proliferated duct epithelial cells, though no typical structure of epimyoepithelial islands seen in Sjögren's syndrome was found. Anti-salivary duct antibody was detected in only one case.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00585496
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  • 80
    Digitale Medien
    Digitale Medien
    A morphological study of the changes which occur during pregnancy in the human breast (1983)
    Springer
    Virchows Archiv 401 (1983), S. 163-175 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Breast ; Human ; Pregnancy ; Ultrastructure ; Morphology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In this study the structural changes which occur during human pregnancy were examined by light and electron microscopy. Pregnancy was associated with proliferation and differentiation of the epithelial cells within the lobules. Proliferation was continuous throughout pregnancy with a progressive increase in the size of the lobules. The highest level of mitosis was observed in the first trimester with lower levels in the second and third trimesters. Unexpectedly a number of apoptotic cells were observed during pregnancy. Differentiation was initiated in the second trimester with an increase in the amount of rough endoplasmic reticulum and the appearance of a hypertrophic Golgi body and lipid droplets within a number of epithelial cells. A number of small vacuoles were present close to the apical plasmalemma of a few epithelial cells. As the pregnancy proceeded there was an increase in the number of cells exhibiting these features. There was also an increase in the size of the lipid droplets and the number of apical vacuoles. The apical vacuoles which have not been described previously range in size from 150–600 nm with the contents of the larger vacuoles having a whorled or labyrinth-like appearance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00692642
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  • 81
    Digitale Medien
    Digitale Medien
    Effect of hyperthermic vesical irrigation with bleomycin on the ultrastructure of the well-differentiated tumour and non-tumorous mucosa of the human urinary bladder (1983)
    Springer
    Urological research 11 (1983), S. 131-137 
    Details
    ISSN: 1434-0879
    Schlagwort(e): Human bladder tumour ; Non-tumorous human bladder mucosa ; Hyperthermic vesical irrigation ; Bleomycin ; Ultrastructure ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Bladder tumours and non-tumorous bladder mucosa were studied by scanning and transmission electron microscopy in seven patients who had undergone hyperthermic vesical irrigation with bleomycin. The treatment induced sloughing of the outermost tumour cells, an increase of blebs and a decrease of cytoplasmic processes of the deeply located tumour cells as well as cellular degeneration. Although less severe, non-tumorous mucosa showed similar changes. Microvilli also appeared on the superficial cells of non-tumorous mucosa after the treatment. This treatment is effective by inducing cell degeneration and desquamation but not selective to the bladder tumour.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00257718
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  • 82
    Digitale Medien
    Digitale Medien
    Ultrastructural study of the mouse antimesometrial decidua (1983)
    Springer
    Anatomy and embryology 166 (1983), S. 263-274 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Decidua ; Ultrastructure ; Mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of mouse antimesometrial decidual cells was analyzed during the development of the decidua between days 5 and 8 of pregnancy. The first decidual cells, appearing on the 5th day, are polygonal with rounded nuclei and prominent nucleoli; free ribosomes predominate in the cytoplasm. On the 6th to the 8th days the cytoplasm of these cells is typically that of cells actively engaged in macromolecular synthesis. Large numbers of granular and agranular endoplasmic reticulum cisternae are present in addition to well-developed Golgi complexes, mitochondria and lysosomes. Many bundles of microfilaments and lipid droplets occur during this period. An intense accumulation of autophagosomes and lysosomes with very heterogeneous content was noted on the 7th and especially the 8th days. The presence of these organelles is an indication that involution of this part of the decidua has begun.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305087
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  • 83
    Digitale Medien
    Digitale Medien
    Ultrastructure of the absorptive cells in the small intestine of the rat during starvation (1983)
    Springer
    Anatomy and embryology 168 (1983), S. 331-339 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Ultrastructure ; Starvation ; Absorptive cells ; Small intestine ; Rats
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of the absorptive cells in the duodenum, jejunum and ileum after 7, 14 and 21 days of starvation was investigated using rats aged from 12 to 18 months weighing about 500 g. In the basal cytoplasm of the absorptive cells (in the duodenum and ileum of 21-day-starved rats and the jejunum of 14- and 21-day-starved rats), the following changes were found: atrophied mitochondrion-like bodies, small vesicles, a short and sparse rough-surfaced endoplasmic reticulum and a lack of density in a portion of the cytoplasm. Moreover, many autolysosomes of various sizes and shapes were encountered in the basal cytoplasm; occasionally these elements accumulated and appeared to fuse to one another. In contrast, in the apical cytoplasm of absorptive cells in the intestine of starved rats, the ultrastructure was similar to that of control rats. It was considered that the apical cytoplasm of the absorptive cells in the starved rat intestine might be preserved as long as possible during starvation in order to absord nutrients when they become available again.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00304271
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  • 84
    Digitale Medien
    Digitale Medien
    An ultrastructural study of experimental high velocity penetrating head injury (1983)
    Springer
    Acta neuropathologica 59 (1983), S. 277-282 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Trauma ; Missile head injury ; Astrocyte ; Blood brain barrier ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Experimental high velocity missile brain injury in the rhesus monkey produces widespread swelling of perivascular astrocytes within 30 min of injury. Possible mechanisms for this lesion include a direct effect of force, chemical mediation secondary to the extravasation of blood, alterations in the permeability of the blood brain barrier and ischaemia. The implications of this finding for the function of the blood brain barrier, for neurotransmission and for neuronal survival are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00691493
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  • 85
    Digitale Medien
    Digitale Medien
    Oligodendroglioma-like cells (clear cells) in ependymoma (1983)
    Springer
    Acta neuropathologica 62 (1983), S. 141-144 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Ependymoma ; Clear cells ; Oligodendroglioma-like cells ; Mixed glioma ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A brain tumor of a 22-year-old man was composed mostly of round cells with perinuclear halos (clear cells), forming clusters intersected by small blood vessels. In some areas, the tumor cells showed perivascular arrangement and epithelial pattern. Phosphotungstic-acid hematoxylin stain and immunoper-oxidase stain for glial fibrillary acidic protein (GFAP) technique failed to stain the clear cells. Electron microscopy of the clear cells revealed them to be classical ependymoma cells with well developed intercellular junctions, microvilli and cilia. As no reporters in the past showed the evidence to clarify the nature of the clear cells, this case is considered a good example to support the viewpoint that the clear cells (oligodendroglioma-like cells) commonly observed in ependymomas are in reality ependymoma cells. It is stressed that the diagnosis of “mixed glioma” or “oligoependymoma” should be made with sufficient caution despite the recent advances of GFAP technique.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00684931
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  • 86
    Digitale Medien
    Digitale Medien
    Cerebral ischemia in the rat: Ultrastructural and morphometric analysis of synapses in stratum radiatum of the hippocampal CA-1 region (1983)
    Springer
    Acta neuropathologica 61 (1983), S. 52-60 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Ischemia ; Brain ; Hippocampus ; Synapses ; Ultrastructure ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A 10-min long ischemic insult followed by up to 60-min survival results in several changes of the synaptic ultrastructure in the hippocampal CA-1 region. The alternations consist of gradual change of synaptic curvature from neutral to positive, cleavage and decrease in thickness of the postsynaptic densities and, in the case of many terminals, wrinkling of their profiles. The most striking form of damage are membrane discontinuities which begin to appear in very small numbers after 20 min of blood reflow and become much more pronounced after 60 min. The development of those modifications seems to be time-related, whereas decrease in the number of synaptic vesicles, as shown by the morphometric analysis, occurs after 10 min and does not progress any further after 20 and 60 min. This decrease is most pronounced in the immediate vicinity of the presynaptic membrane. Although the observed signs of ultrastructural alternations of synapses in the postischemic period appear to conform to the general pattern of synaptic degeneration observed under other conditions, the severity of ischemia is underlined with the rate at which those changes develop, thus pointing toward grossly disturbed metabolism of postischemic neurons. Recently, a number of theories have been advanced, discussing significance of ischemic destruction of membrane phospholipids. These theories are discussed in the context of membrane discontinuities reported in this investigation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00688386
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  • 87
    Digitale Medien
    Digitale Medien
    Neuropathological findings of an autopsy case of adult β-galactosidase and neuraminidase deficiency (1983)
    Springer
    Acta neuropathologica 61 (1983), S. 283-290 
    Details
    ISSN: 1432-0533
    Schlagwort(e): β-Galactosidase and neuraminidase deficiency ; Neuronal inclusion bodies ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An autopsy case of a Japanese male with familial β-galactosidase and neuraminidase deficiency is reported. The clinical picture was characterized by adult onset, a gargoyle-like face, cerebellar ataxia, myoclonus, convulsions, retinal degeneration and cortical blindness. Histopathologically, most neurons seemed to have become degenerated in the whole cerebral cortex. Moreover, the calcarine cortex appeared spongy with depopulation of nerve cells. Stuffed neurons or neuronal storage changes were found throughout the brain, especially in the motor nuclei of the spinal cord and brain stem. The inclusions in the stuffed neurons revealed various profiles on the electron microscope. They were composed of membranous lamellar and/or multilamellar structures, often accompanying vacuoles and reminiscent of lipofuscin-like profiles.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00691999
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  • 88
    Digitale Medien
    Digitale Medien
    Ultrastructural study on nervous system of fetus with GM1-gangliosidosis type 1 (1983)
    Springer
    Acta neuropathologica 61 (1983), S. 15-20 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Ultrastructure ; Fetus ; Nervous system ; GM1-gangliosidosis type 1
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The nervous system of a 22-week-old fetus with GM1-gangliosidosis type 1 was studied by electron microscopy. The tissues thus examined were the cerebral cortex at the parietal region, the cerebellum, the thoracic spinal cord, the Auerbach's myenteric plexus in the large intestine and the radial nerve fibers. In the cerebral cortex, membrane-bound vacuoles, which occasionally contained stacks of fine fibrils, were observed in the large young neurons in the deeper part of the cortical plate. The neurons in the other part of the cerebral cortex carried no storage materials. In the cerebellum, the membrane-bound vacuoles with stacks of fine fibrils were seen only in the Purkinje cells. The neurons in the spinal cord also contained several zebra-like bodies and the above membrane-bound vacuoles. As for the peripheral nervous system (PNS), neurons in the Auerbach's myenteric plexus carried membranous cytoplasmic bodies and zebra-like bodies. Some of the axons in the radial nerve fibers also contained a lot of pleomorphic electron-dense bodies and a few membranous cytoplasmic ones. These results show that the accumulation of storage materials is started in the large neurons which are produced in the early stage of neurogenesis in the central nervous system (CNS). Additionally, the observed membrane-bound vacuoles are considered to be structures which occur before the membranous cytoplasmic bodies and/or the zebra-like bodies. It is also elucidated that the PNS is affected earlier than the cerebral and cerebellar cortices and thoracic spinal cord.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00688381
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  • 89
    Digitale Medien
    Digitale Medien
    Specific ultrastructural markers of human pinealomas (1983)
    Springer
    Acta neuropathologica 62 (1983), S. 31-40 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Human pinealomas ; Ultrastructure ; Specific markers ; Pinealocyte
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An ultrastructural study of four pinealomas was carried out to precise eventual specific markers. Dark and clear cells joined with zonulae adherents, extensive and pleiomorphous processes, a complex vacuolar system, and characteristic organelles (lysosome-like structures, clear and dense-core vesicles, vesicle-crowned rodlets and related structures, microtubular sheaves and centriolar derivatives, membranous whorls, fibrous bodies, microtubules, heterogeneous cytoplasmic inclusions) offered a typical pattern. No correlation could be made between the histological and ultrastructural features. The authors stress the ultrastructural similarities between the human tumor cells and the mammalian pineal cells. Pinealomas appeared as a morphological entity distinct from neuronal and astrocytic tumors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00684917
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  • 90
    Digitale Medien
    Digitale Medien
    Uterine glands of the pig during pregnancy (1983)
    Springer
    Anatomy and embryology 166 (1983), S. 121-134 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Uterine glands ; Pig ; Ultrastructure ; Cytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of the porcine uterine glands is described from material taken from 11 pregnant pigs at exactly known stages of gestation (day 30; 58; 80; 100; 110). Fixation was performed by perfusion via a branch of the uterine artery and the tissue was routinely processed for electrom microscopy. Additionally, cytochemical studies (phosphotungstic acid reaction for glycoproteins, according to Rambourg 1967; acid phosphatase reaction; ultrastructural localization of cellular iron, according to Parmley et al. 1978) were performed. On day 30 of pregnancy the uterine glands are coiled, simple tubular glands with a narrow lumen. The epithelial lining is simple columnar and consists basically of two cell types, ciliated cells and secretory cells. The secretory activity of the glandular epithelium is low; only a few secretory granules are present in the supranuclear cytoplasm. At midpregnancy the ultrastructure of the glands has significantly changed and the cells now show all the characteristics of high secretory activity: numerous parallel cisternae of rough endoplasmic reticulum, an extensively developed Golgi apparatus and many secretory granules which give a positive reaction for acid phosphatase and glycoproteins. The lumina of the glands are significantly enlarged and filled with a great amount of a granular, acid phosphatase-positive material. In the last third of pregnancy, only minor changes in the ultrastructure of the uterine glands are observed. The secretory activity is still high. The amount of rough endoplasmic reticulum has further increased and parallel arrays of cisternae occupy a considerable part of the supranuclear cytoplasm. The importance of the uterine secretion for embryonic nutrition and development is only partly understood. One of the secreted glycoproteins, uteroferrin, is believed to play an important role in the iron transfer from mother to fetus. From midpregnancy onward, a special cell type, the “granule laden cell” is found scattered between normal secretory cells of the uterine glands. Contrary to the opinion of Perry and Cromby (1982), we could demonstrate that these cells frequently extend to the lumen of the gland; hence the term “basal cell” seems inappropriate for this cell type.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00317948
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  • 91
    Digitale Medien
    Digitale Medien
    A fine structural study of the cells that proliferate in the partially denervated dentate gyrus of the rat (1983)
    Springer
    Anatomy and embryology 166 (1983), S. 317-332 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Dentate gyrus ; 3H-thymidine ; Glial cells ; Proliferation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Tritiated thymidine autoradiography has established that after interrupting the commissural afferents to the dentate gyrus a number of non-neuronal cells proliferate in the molecular layer. In the present study the fine structure of the proliferating cells was analyzed by reembedding the 2-μm thick plastic sections of the dentate gyrus which had been previously coated with a nuclear emulsion and processed for light microscopic autoradiography. The location of the labeled cells was plotted with a camera lucida and a few ultrathin sections were taken from the re-embedded sections. In these the labeled cells were re-identified and photographed in an electron microscope. Most of the identified proliferating cells exhibited the following morphological features: The nuclei were irregularly oval, sometimes with deep indentations and contained dense clumps of chromatin; their diameters ranged between 4.5 and 6.5 μm. The cytoplasm was generally disposed to one side of the nucleus and often extended into a few broad processes. The Golgi apparatus was well developed. Many rosettes of free ribosomes were scattered throughout the cytoplasm, and the rough endoplasmic reticulum usually consisted of a few short cisternae. Small multilamellated bodies were common, but dense inclusion bodies were infrequent. The observations reported in this paper suggest: 1. that the nonneuronal cells which proliferate in a neuropil undergoing a mild denervation are morphologically closely related to microglia; 2. that in young adult animals these cells do not seem to have been previously involved in intense phagocytic activity; and 3. that the proliferating cells are present in the neuropil at the time of the denervation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305921
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  • 92
    Digitale Medien
    Digitale Medien
    Effect of prepuberal castration on porcine bulbospongiosus muscle (1983)
    Springer
    Anatomy and embryology 168 (1983), S. 51-58 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Bulbospongiosus muscle ; Histochemistry ; Ultrastructure ; Castration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The histochemical profile and ultrastructural properties of the bulbospongiosus muscle (BSM) fibers from 5–6 month old boars and barrows (castrated at 7 days of age), and intact week old piglets were compared. Based on myosin ATPase, preincubated at pH 4.2, BSM of boars contained predominately intermediately staining fibers, whereas BSM of barrows and piglets had a mixture of staining intensities. Fibers from boar BSM stained intensely for SDH, with subsarcolemmal and diffuse location of reaction product. Staining intensity for SDH was variable in BSM from barrows and piglets, with diffuse location of reaction product. The BSM of boars and barrows contained predominately dark fibers when stained for glycogen and phosphorylase, and the fibers were low in stored lipids. While the fibers were smaller in barrow as compared to boar BSM, ultrastructural differences between boar and barrow BSM were not detectable.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305398
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  • 93
    Digitale Medien
    Digitale Medien
    Studies of the guinea pig epididymis (1983)
    Springer
    Anatomy and embryology 168 (1983), S. 195-209 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Epididymis ; Guinea pig ; Principal cells ; Zonula occludens ; Zonula adhaerens ; Ultrastructure ; Freeze fracture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The junctional complexes of the principal cells in the guinea pig epididymis were analyzed using freeze fracture and ultrathin section goniometric techniques. Replicas of the seven regions (I to VII) investigated reveal a continuous decrease in the number of tight junctional strands, ranging from 15.73±3.54 in zone I (proximal) to 4.39±0.78 in zone VII (distal tubule). The distance from the adluminal to the basolateral strand also diminishes from proximal, 0.73±0.02 μm to distal, 0.19±0.03 μm. The junctional strands appear on the P-face and anastomose forming compartments which are larger in the basolateral areas than those in the apical. The network of strands frequently form terminal loops and blind endings towards the more basal parts of the lateral membrane. Freeze fracture images also exhibit randomly distributed particulate aggregations which correspond to maculae adhaerentes, the highest number of which are found in zone IV, V, and VII. Desmosomal figures are found not only below, but also adjacent and intermingled among the tight junctional strands. This special junctional arrangement is confirmed upon goniometric analysis of ultrathin sections from zones IV, V, and VII. Electron dense desmosomal plaques are seen parallel and directly subjacent to the membranes of the tight junctions, following the strands in both directions to finally converge on the punctiform connections. Goniometry also reveals a dense feltwork of material closely applied along the lateral cell border. These zonulae adhaerentes are seen to be of greatest length and density in zones I, VI, and VII.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00315816
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  • 94
    Digitale Medien
    Digitale Medien
    An ultrastructural study of lactation in the human breast (1983)
    Springer
    Anatomy and embryology 168 (1983), S. 349-359 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Breast ; Human ; Lactation ; Ultrastructure ; Morphology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In this study the morphological features of lactation in the human breast were examined by scanning and transmission electron microscopy. The lactating lobules comprised large numbers of interconnecting acini which were lined by a single layer of epithelial cells with underlying myoepithelial cells. Marked variations were noted in the shape of the epithelial cells. The myoepithelial cells formed an open meshwork of interconnecting cytoplasmic processes packed with myofibrils. The basal cytoplasm of the epithelial cells was packed with rough endoplasmic reticulum while the apical cytoplasm contained a hypertrophic Golgi body, numerous vacuoles (a few of which contained casein micelles), a number of lipid droplets and small coated and uncoated vesicles. The lipid droplets were released by progressive protrusion from the apical surface. They remained covered by the plasmalemma and were finally budded off into the lumen. In certain cases a portion of cytoplasm was released with the lipid droplet. The vacuoles and small vesicles fused with the plasmalemma and released their contents by exocytosis. Within the samples the majority of epithelial cells were actively lactating although examples of undifferentiated “resting” and dead (lysed) cells were also identified.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00304273
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  • 95
    Digitale Medien
    Digitale Medien
    Studies of the guinea pig epididymis (1983)
    Springer
    Anatomy and embryology 168 (1983), S. 173-194 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Epididymis ; Guinea pig ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The guinea pig epididymis is subdivided into seven zones. The ultrastructure and morphology of the principal cells in these zones is analyzed. The position, shape and content of the nuclei are variable along the length of the epididymal duct. Features characteristic of absorptive activity, such as micropinocytotic caveolae, vacuoles, and multivesicular bodies are of high concentration in zone IV and VI. The Golgi apparatus, rough endoplasmic reticulum and secretion granules are organelles and inclusions implicated to secretory functions and in this study are not found in the following concurring amounts within the principal cells of the seven zones: the Golgi apparatus exhibits a trend of increase from zone II to zone VII while the rough endoplasmic reticulum decreases. Secretion granules, though, are detected only in zones II and III, not only in the supra-, but also in the peri-and infranuclear regions. This possibly implies an exocrine secretory functions. Lamellar whorls and profiles of tubular smooth endoplasmic reticulum are concentrated in the supranuclear and adluminal regions of zones I, II and VI. A high concentration of large lipid droplets is a consistent feature of the perinuclear region of zone II. Mitochondia and lysosomes are detected in relatively large amounts along the epididymal duct. The correlations of these morphological characteristics with respect to their possible functional role are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00315815
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  • 96
    Digitale Medien
    Digitale Medien
    Neurofibromatosis tumor and skin cells in culture (1983)
    Springer
    Acta neuropathologica 61 (1983), S. 275-282 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Neurofibromatosis ; Cell culture ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Skin fibroblasts and tumor cells were cultured from four patients with peripheral von Recklinghausen's neurofibromatosis (NF). The cell type enriched in culture from the tumors carried the fibroblastic Thy 1.1. cell surface antigen and produced fibronectin, like fibroblasts from skin of NF-patients or from control persons. In electron micrographs the NF tumor and NF skin cells were similar to the control skin fibroblasts; elongated in shape, contained tubular mitochondria, variable amounts of granular endoplasmic reticulum, numerous lysosomal inclusion bodies and collections of 5 nm filaments. Trypsinized cells were fractionated with centrifugation in a Percoll density gradient. All cell lines produced only one sharp band of viable cells at the buoyant density of 1.03. Compared with the NF skin or control skin fibroblasts the NF tumor cells, however, produced a less well organized peri-and extracellular matrix estimated from fibronectin fluorescence. The nuclear sizes were measured from photographs of the cultures. The nuclei of all four tumor cell lines were larger than those of the skin fibroblasts of the corresponding patients. Neurofibromatosis tumor cells thus resemble skin fibroblasts in their density and in some ultrastructural properties but are different in their growth pattern and synthetic functions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00691998
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  • 97
    Digitale Medien
    Digitale Medien
    Pituitary adenomas: Immunohistology and ultrastructural analysis of 118 tumors (1983)
    Springer
    Acta neuropathologica 62 (1983), S. 1-14 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Pituitary adenomas ; Immunohistology ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An analysis is presented of the immunohistological and ultrastructural features in a series of 118 surgically removed pituitary adenomas all of which were studied immunohistologically using antisera to growth hormone (GH), prolactin (PRL) ACTH, βFSH, βLH and βTSH, and 75 of which were studied ultrastructurally. Results were analysed according to the mode of presentation of patients. Forty-one (35%) of the tumours were from patients with acromegaly or gigantism, ten (9%) from patients with Cushing's syndrome or Nelson's syndrome, 19 (16%) from patients with clinical features associated with hyperprolactinaemia and 48 (40%) from patients with space occupying lesions which appeared clinically to be overtly endocrinologically functionless. By light microscopy, using the immunoperoxidase (PAP) technique, immunoreactive GH was demonstrated in all the tumours from patients with acromegaly or gigantism, immunoreactive ACTH in all tumours from patients with Cushing's syndrome or Nelson's syndrome and immunoreactive PRL in 95% of tumours associated with effects of hyperprolactinaemia. Forty-five percent of the tumours from acromegalic patients contained some PRL-positive cells as well as GH-positive cells. Among the tumours which appeared clinically to be endocrinologically functionless were three tumours (from males) uniformly stained for immunoreactive PRL. Of the remainder, 60% were negative for immunoreactive hormones and 40% contained small numbers of cells which were positive for a variety of immunoreactive hormones. ACTH-cell and PRL-cell tumours had ultrastructural features as described in previous studies. Fifty percent of GH-cell tumours examined at the EM level contained fibrous bodies, while in the remainder these structures were not identified. Tumours with fibrous bodies were more likely to contain PRL as well as GH with immunoperoxidase. All tumours that were endocrinologically functionless and which were examined at the EM level contained secretory granules. Oncocytic change was common in these tumours. No ultrastructural differences were observed between those which contained immunoreactive hormones by light microscopy and those which did not.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00684914
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  • 98
    Digitale Medien
    Digitale Medien
    An ultrastructural study of epidermolytic leukoplakia (1983)
    Springer
    Archives of dermatological research 275 (1983), S. 86-91 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Vermilion of the lip ; Leukoplakia ; Epidermolytic hyperkeratosis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A leukoplakic lesion of the lip showing the histologic features of epidermolytic hyperkeratosis above solar elastosis was investigated by electron microscopy. The ultrastructural alterations observed in the upper epidermal layers corresponded in the main with those of epidermolytic hyperkeratosis in other skin diseases. The keratinocytes showed irregularly formed tonofilaments, a marked intracellular edema, and premature cornification. In addition, there were discrete subcellular signs of premalignancy in the cells of the basal and suprabasal layers. These alterations suggest that the epidermolytic leukoplakia represents a rare histopathologic variant of actinic cheilitis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00412880
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  • 99
    Digitale Medien
    Digitale Medien
    Ultrastructural localization of adenylate cyclase and cAMP phosphodiesterase in the gastrulating chick embryo (1983)
    Springer
    Development genes and evolution 192 (1983), S. 42-44 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Chick embryo ; Gastrulation ; Adenylate cyclase ; cAMP phosphodiesterase ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ultrastructural localization of adenylate cyclase (E.C. 4.6.1.1.) and cAMP phosphodiesterase (PDE) (E.C. 3.1.4.17.) in the ectoderm of the developmental stage 4 chick embryo was studied. Adenylate cyclase was localized in the lateral surfaces of the ectodermal cells. In the primitive streak cells the enzymatic activity was observed on all the lateral surfaces, whereas in the periphery of the blastoderm the reaction product was localized in the apical parts of the lateral plasma membranes only. cAMP PDE localized in the apical cytoplasm of the ectodermal cells, with highest activity in the globular projections.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848768
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  • 100
    Digitale Medien
    Digitale Medien
    Electron microscopical study of self-differentiation potency in the chick embryonic endoderm cultured in vitro (1983)
    Springer
    Development genes and evolution 192 (1983), S. 171-178 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Differentiation ; Digestive tract ; Endoderm ; Organ culture ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The self-differentiation potency of the endoderm of the chick embryo was investigated mainly by transmission electron microscopy. Endodermal fragments isolated from 4- to 6-day stomach or small intestine were cultured in the absence of mesenchyme and were able to differentiate in vitro into organ-specific epithelia. Endodermal fragments isolated from the stomach region differentiated into a pseudo-stratified epithelium with periodic acid Schiff-positive mucous granules in the apical cytoplasm, while those from the small intestinal region differentiated into a simple columnar epithelium with a striated border which was positive in alkaline phosphatase activity. These features are comparable with those of the mucous secretory epithelium of the normal embryonic stomach and the absorptive epithelium of normal embryonic small intestine, respectively. Next, the self-differentiation potencies were investigated of the upper and lower layers of the blastoderms, at stages 1–5 of Hamburger and Hamilton (H. and H.). Both stomach-type and small-intestine-type epithelia developed only when fragments of the lower layer isolated from the blastoderms older than stage 3 of H. and H. were cultured, suggesting that cells possessing the potency to differentiate into the stomach- and small-intestine-type epithelia exist in the definitive endoderm at the beginning of its formation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848687
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