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  • 1995-1999
  • 1990-1994  (1.676)
  • 1980-1984  (1.167)
  • 1970-1974  (871)
  • 1992  (1.676)
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  • 1974  (871)
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  • Ultrastructure  (305)
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  • Nuclear reactions
Datenquelle
Materialart
Erscheinungszeitraum
  • 1995-1999
  • 1990-1994  (1.676)
  • 1980-1984  (1.167)
  • 1970-1974  (871)
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Cell populations in the lesion of human cutaneous leishmaniasis: A light microscopical, immunohistochemical and ultrastructural study (1992)
    Springer
    Virchows Archiv 421 (1992), S. 239-247 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Human cutaneous leishmaniasis ; Skin ; Immunohistochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary To characterize the in situ cellular immune response in localized cutaneous leishmaniasis (LCL), the authors studied frozen skin biopsies from 50 patients with LCL due toLeishmania braziliensis guyanensis. A panel of 31 monoclonal antibodies was used, which defined the number and distribution of inflammatory cell subsets. Skin inflammatory infiltrates were composed of T cells (with a local CD4/CD8 ratio of 1.05±0.7 vs 1.48±0.3 in peripheral blood), macrophages and a smaller number of B cells, natural killer cells and granulocytes. Most of the T cells expressed activation markers (interleukin-2 and transferrin receptors, HLA-DR+) and an increase in T-cell-receptorγδ expression was noted. Analysis of the CD4+ subpopulations with newly available reagents showed that helper T cells (CD4+CD45RO+) exceeded the suppressor/inducer subset (CD4+CD45RA+) by 1.4∶1. There were no differences between local immune variables from patients with primary infection (45 patients) and those with recurrence (5). In 7 patients, biopsies were analysed before and 1 month after specific treatment, and did not show significant differences except for a small increase of dermal CD1a+ (Langerhans) cells/mm2. The observed pattern of cellular skin infiltration suggests an immune-mediated tissue injury including T-cell-mediated cytotoxicity and delayed hypersensitivity reactions in addition to direct parasitic action.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01611181
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  • 2
    Digitale Medien
    Digitale Medien
    The glomerular mesangium: capillary support function and its failure under experimental conditions (1992)
    Springer
    Journal of molecular medicine 70 (1992), S. 843-856 
    Details
    ISSN: 1432-1440
    Schlagwort(e): Kidney ; Glomerulus ; Mesangium ; Mesangial failure ; Electron microscopy ; Animal models
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We present a structural analysis of the ability of the biomechanical unit consisting of mesangium and glomerular basement membrane to maintain normal capillary architecture in the face of mechanical challenges due to high intraglomerular pressures. Capillary support function may be considered in terms of the stabilization of local form (development of wall tension against capillary dilation) and global form (centripetal fixation of capillary loops to maintain higher order form). The pathologic consequences of the loss of this support are illustrated by way of experimental models of mechanical mesangial failure. Such failure may express itself as mesangial widening, increased transmesangial macromolecule “traffic,” ballooning of capillary segments, and unfolding of capillary loops. Mechanisms are described by which these structural changes may lead to segmental glomerular sclerosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00180755
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  • 3
    Digitale Medien
    Digitale Medien
    TNF induces cytoplasmic vesicles in actinomycin D-treated K 562 cells (1992)
    Springer
    Annals of hematology 65 (1992), S. 50-52 
    Details
    ISSN: 1432-0584
    Schlagwort(e): TNF ; K 562 ; Leukemia ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We report here that tumor necrosis factor alpha (TNF) induces peculiar cytoplasmic vesicles in the human erythromyeloid leukemia cell line K 562, sensitized to the cytotoxic action of TNF by a treatment with the inhibitor of transcription actinomycin D. These vesicles are well delineated ultrastructurally. The formation of these vesicles is characteristic for the combination of actinomycin D with TNF and precedes the changes of apoptosis and cellular disintegration. These vesicles correspond to an intermediate step in the cytotoxicity caused by TNF and may indicate that reactive metabolites are involved in the mechanism of action of TNF.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01715127
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  • 4
    Digitale Medien
    Digitale Medien
    In vitro formation of mineralized nodules by periodontal ligament cells from the rat (1992)
    Springer
    Calcified tissue international 50 (1992), S. 459-467 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Periodontal ligament fibroblast ; Mineralized nodule ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The purposes of this study were to determine whether periodontal ligament (PDL) cells are capable of producing mineralized nodules in vitro and to analyze ultrastructural features of the nodules. Rat PDL cells were obtained from coagulum in the socket at 2 days after tooth extraction and cultured at confluence in standard medium containing Dulbecco's Modified Eagle's Medium supplemented with 10% FBS and antibiotics. To test mineralized nodule formation, cells were further cultured for an additional 3 weeks in the standard medium containing (1) ascorbic acid (50 μg/ml) and sodium β-glycerophosphate (10 mM), (2) ascorbic acid, sodium β-glycerophosphate, and dexamethasone (5 μM), or (3) ascorbic acid alone. Cells were then fixed in 2.5% glutaraldehyde, postfixed in 1% OsO4, and prepared for light and electron microscopy. Threedimensional nodules containing mineralized matrices were formed only when the cells were cultured in the presence of ascorbic acid and dexamethasone. They were composed of multilayered fibroblasts (up to 13 layers), and highly organized collagen fibrils with 64 nm cross-banding patterns between the cell layers. The fibroblasts in the nodules exhibited an elongated shape with a high degree of cytoplasmic polarity throughout the nodule, and have the morphological features of PDL fibroblasts as seen in vivo. Mineral deposition with needle-like crystals was initiated on collagen fibrils located in intercellular spaces of the upper cell layers and became increasingly heavier towards the bottom half of the nodules. X-ray microanalysis and electron diffraction analysis confirmed that mineral deposition contained calcium and phosphate in the form of immature hydroxyapatite. These nodules contained neither osteoblasts nor osteocytes, and have their own morphological organization and characteristics which differ from those formed by bone cells in culture. Therefore, these data suggest that PDL cells are capable of forming mineralized tissue in vitro with the morphological characteristics different from bone mineralized nodules.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00296778
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  • 5
    Digitale Medien
    Digitale Medien
    Ultrastructure and cytochemistry of circulating erythrocytes during the annual cycle of Rana esculenta L. (1992)
    Springer
    Comparative clinical pathology 2 (1992), S. 166-169 
    Details
    ISSN: 1433-2981
    Schlagwort(e): Erythrocytes ; Flow cytometry ; Frog hibernation ; Image analysis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Morphometrical (image analysis of cell and nuclear shape factor), morphological (electron microscopy) and cytochemical (acridine orange fluoro-chromasia and propidium iodide-DNA flow cytometry) features of circulating red blood cells were investigated during two periods of the annual cycle of Rana esculenta: the active phase (July) and the underground hibernating phase (January). The results showed that the hibernating phase is marked by more homogeneity of the red cells, both at nuclear (strongly condensed chromatin) and cytoplasmic level (loss of intact organelles and acridine orange fluorochromasia). The almost complete disappearance of the ‘immature’ erythrocytes from the circulation, during the hibernating phase, should be related to a decrease of haemopoietic activity and to an increase of life span accompanied by uncommon storage in different organs both at vascular and intracellular level.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00426172
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  • 6
    Digitale Medien
    Digitale Medien
    A unique case of naturally occurring mummification of human brain tissue (1992)
    Springer
    International journal of legal medicine 105 (1992), S. 173-175 
    Details
    ISSN: 1437-1596
    Schlagwort(e): Human brain tissue ; Natural mummification ; Histology ; Histochemistry ; Electron microscopy ; Elemetal analysis ; Gehirn ; Mensch ; Naturaliche Mumifikation ; Histologie ; Histochemie ; Elektronenmikroskopie ; Atmospektralanalyse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Rechtswissenschaft
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei Ausgrabungen in Bulgarien wurden Schädel und Knochen von 39 Individuen im Alter zwischen 35 und 60 Jahren, die vor ca. 45–50 Jahren begraben wurden, gefunden. Bei der nachfolgenden gerichtsmedizinischen Experitse wurden in zwei intakten Schädeln und zwischen den Knochen anderer Schädel sieben harte Gebilde (zwei ganze und fünf Fragmente), die wie geschrumpfte menschliche Gehirne aussahen, identifiziert. Entsprechende Proben von diesem Material wurden für 3–4 Tage mit 15% wässriger Lösung von Glycerol weicher gemacht und danach lichtmikroskopisch und elektronenmikroskopisch untersucht. An entsprechenden Stückchen von frischem menschlichem Gehirn und den gefundenen Proben wurde eine Atomspektral-analyse zur Bestimmung des chemischen Bestandes an Elementen durchgeführt. Die komplexe Untersuchung des Materials ergab, daß es sich bei diesem Fund um einen Sonderfall von natürlich mumifizierten menschlichen Gehirnen handelt, die durch sonderbare Bedingungen nur im Schädel der begrabenen Individuen entstanden sind.
    Notizen: Summary When skulls and bones were exhumed from a mass grave in Bulgaria and subjected to medicolegal examination they were found to originate from 39 humans aged 36–60 years old who had been buried approximately 45–50 years ago. Solid structures which strongly resembled shrunken human brain tissue were found inside 2 intact skulls. Among other bones 5 similar structures were found one of which was an almost entirely preserved human brain, and the others were fragments from different regions of the human brain. Samples of these structures were immersed in 15% aqueous glycerol solution to soften and were examined by light and electron microscopy. Sampels of this material and of fresh human brain were subjected to elementary atomic spectral analysis. These complex studies indicated the samples to be naturally mummified human brain tissue and that this process had occurred due to specific conditions within the cranial cavities after burial.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01625172
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  • 7
    Digitale Medien
    Digitale Medien
    Vascular and myofibrillar lesions in acute myoglobinuria associated with carnitine-palmityl-transferase deficiency (1992)
    Springer
    Virchows Archiv 421 (1992), S. 57-64 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Carnitine-palmityl-transferase deficiency ; Acute vascular lesions ; Acute myofibrillar lesions ; Ischaemia ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A case of severe exercise-induced myoglobinuria in a 14-year-old boy suffering from a carnitine-palmityl-transferase (CPT) defect is reported. Biopsies of the forearm muscle were examined using light and electron microscopy in the acute and recovery phases of the illness. The first biopsy showed the presence of scattered foci of necrosis where necrotic fibres with occasional disruptions of the basal lamina were seen around injured capillaries. Various degrees of damage and different stages of evolution were found in these foci, which also contained regenerating muscle fibres. In the second biopsy, performed 2 weeks later, most of the fibres displayed a normal structure. Necrosis was no longer present. However, in some areas perivascular fibrosis was prominent, the fibres were small and irregularly shaped, and their nuclei often centrally located. These data strongly suggest that circulatory disorders and ischaemia, brought about by premature acute metabolic imbalance, could be involved in the development of exerciseinduced myolysis observed in CPT deficiency. The risk of fibrous cardiomyopathy in these patients is pointed out.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01607140
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  • 8
    Digitale Medien
    Digitale Medien
    The pathobiology of salivary gland (1992)
    Springer
    Virchows Archiv 421 (1992), S. 105-113 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Parotid gland ; ras ; Transgenic mouse ; Electron microscopy ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In the transgenic TG.SH (mouse mammary tumour virus/v-Ha-ras) mouse, designed to develop mammary tumours, occasional spontaneous salivary gland tumours have been reported, predominantly in males. The incidence and histomorphology of salivary gland tumours in 73 TG.SH mice were surveyed and in total, 21.9% developed both overt and microscopic parotid tumours. The majority developed between 73 and 150 days of age. In 31.5% of the TG.SH mice, occasional unilateral, but more frequently bilateral exophthalmos due to hyperplasia of the intraorbital (Harderian) lacrimal gland was observed. In 70% of these animals, parotid tumours developed later. Since Harderian gland hyperplasia, occurring as early as 5 weeks of age, preceded the development of palpable salivary gland lesions, this stigma is useful for the early selection of animals likely to progress to tumour formation. Before tumour-bearing transgenic mice are considered to be suitable models of human neoplastic disease, morphological characterization is necessary to ensure that the tumours are histologically representative of the human lesions for which they are potential models. In this study, all parotid tumours consisted of acinar-like glandular structures with central lumina discernible by electron microscopy. Ultrastructurally, secretory granules evident in the apical cytoplasm of the tumour cells resembled the zymogen granules of the normal parotid acinar cell, and some cells had a prominent complement of rough endoplasmic reticulum. These features, along with focal amylase expression detected immunohistochemically in some parotid tumours, identified these neoplasms as acinic cell carcinomas that mimic the human salivary gland acinic cell carcinoma faithfully.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01607042
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  • 9
    Digitale Medien
    Digitale Medien
    Eccrine gland involvement in Krabbe's disease (1992)
    Springer
    Virchows Archiv 421 (1992), S. 351-354 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Krabbe's disease ; Eccrine gland storage ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Lysosomal storage inclusions were observed in skin eccrine gland secretory and myoepithelial cells in three cases of Krabbe's disease. In addition to storage there were numerous degenerative changes, occasionally resulting in cell necrosis. These findings suggest a generalized nature of the storage process in this lysosomal enzymopathy and point to high galactocerebroside turnover in eccrine gland epithelium. This knowledge may be of value in the biopsy diagnosis of Krabbe's disease.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01660983
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  • 10
    Digitale Medien
    Digitale Medien
    Multicystic mesothelial proliferation (1992)
    Springer
    Virchows Archiv 421 (1992), S. 379-385 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Multicystic mesothelial proliferation ; Immunohistochemistry ; Ultrastructure ; DNA analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We investigated the clinicopathological findings in five cases of multicystic mesothelial proliferation (MMP). All masses consisted of multiloculated cysts attached to pelvic organs and sometimes growing into the upper abdominal cavity. The cystic spaces were lined by flattened or cuboidal cells. The stroma showed fibrosis, oedema and chronic inflammation. Immunohistochemistry revealed strong positive staining for cytokeratin and epithelial membrane antigen, and focal positivity for vimentin and carcinoembryonic antigen. The endothelial markers were negative. Electron microscopy showed abundant surface microvilli and well-developed basal lamina. DNA analysis identified euploid cell populations in all cases. All but one case had a previous history of abdominal surgery. Despite the worrying appearance the clinical outcome was favourable in all cases; there was one recurrence. Clinical and pathological data support the hypothesis that MMP represent a reactive mesothelial proliferation and not a neoplastic process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01606909
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  • 11
    Digitale Medien
    Digitale Medien
    Immunopathological study of eosinophils in eosinophilic granuloma of bone: Evidence for release of three cationic proteins and subsequent uptake in macrophages (1992)
    Springer
    Virchows Archiv 421 (1992), S. 255-261 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Eosinophilic granuloma of bone ; Eosinophil granule proteins ; Immunostaining ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Eosinophils from two patients with eosinophilic granuloma of bone (EGB) were studied by combined immunohistochemical and immuno-ultrastructural methods with antibodies directed against three eosinophil granule proteins: major basic protein, eosinophil cationic protein, and eosinophil peroxidase. Immunohistostaining showed the presence and distribution of large numbers of eosinophils in the granuloma. Immuno-ultrastructural methods showed alterations of eosinophil fine structure associated with some steps in the release of granule proteins. No granule extrusion was seen, but rather cationic proteins diffused within cytoplasmic tubulo-vesicular structures. Furthermore, the three granule proteins were found within phagolysosomes of surrounding macrophages, suggesting an interaction between eosinophils and phagocytic cells at the destructive stage of EGB.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01611183
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  • 12
    Digitale Medien
    Digitale Medien
    Small cell carcinoma of the ovary: An immunohistochemical and ultrastructural study with a review of the literature (1992)
    Springer
    Virchows Archiv 421 (1992), S. 263-270 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Small cell carcinoma ; Ovary ; Immunohistochemistry ; Ultrastructure ; Literature review
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This is an immunohistochemical and ultrastructural study of two small cell carcinomas of the ovary with a review of the literature. These cases showed a dimorphic population of small and large cells sharply demarcated from each other. Cytokeratin 18 and vimentin were mainly expressed in the large tumour cells, some of which also stained for alpha-smooth muscle actin. Periodic-acid-Schiff-positive, alpha-1-antitrypsin-positive hyaline globules were present in one case. Ultrastructural findings included filamentous nucleolonema as well as evidence of smooth muscle differentiation. Some of these observations have not been previously reported. Certain of the above features seem to support a germ cell origin of small cell carcinoma, but they cannot be considered specific for germ cell neoplasms. Thus, small cell carcinoma of the ovary cannot be classified into one of the known categories of ovarian tumours at the present time.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01611184
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  • 13
    Digitale Medien
    Digitale Medien
    Immunohistochemical and ultrastructural studies of intraluminal crystalloids in human prostatic carcinomas (1992)
    Springer
    Virchows Archiv 421 (1992), S. 421-425 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Crystalloid ; Prostatic cancer ; Epithelial membrane antigen ; Phosphotungstic acid hematoxylin stain ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Intraluminal crystalloids (ICr) observed in 19 cases of incidental or invasive human prostatic carcinoma (PCa) and in a case of benign prostatic hyperplasia were examined extensively by immunohistochemistry and electron microscopy. They were brilliantly eosinophilic with haematoxylin and eosin, manifesting needlelike, triangular, rectangular, hexagonal and irregular lump-like in shape. They were strongly positive, dark blue, with phosphotungstic acid -haematoxylin (PTAH) stain in all cases examined. Among the human antibodies tested, epithelial membrane antigen (EMA) gave specifically positive immunostainability with ICr in all cases. Annual ring-like lamellar or concentric structures were detected by electron microscopy. Positive staining of ICr with PTAH and anti-EMA antibody is very useful as a diagnostic marker for PCa in human prostatic tissues.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01606915
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  • 14
    Digitale Medien
    Digitale Medien
    Ultrastructural observations on cytotoxic effector cells infiltrating pancreatic islets of low-dose streptozocin treated mice (1992)
    Springer
    Virchows Archiv 420 (1992), S. 5-10 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Islets of Langerhans ; Monocytic phagocytes ; Streptozocin ; Type 1 diabetes ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The aim of this study was to observe the ultrastructural events, during the onset of diabetes mellitus in the low-dose streptozocin (LDS)-treated mouse model with emphasis on the infiltrating elements. Forty male C57 BL/6J mice were given 40 mg/streptozocin on 5 consecutive days and killed 5, 6, 7, 8, 9, 10, 15, and 18 days after the first injection. Results demonstrated that islet infiltration occurring in LDS-treated mice is characterized by a very early pre-infiltration state in which mononuclear phagocytes in islet capillary vessels were considerably increased in number. A new histopathological time sequence for the early insulitis is described, in which attraction of blood mononuclear phagocytes into the islet capillary lumen is the first step. During the successive stage, occurring on days 6–8 we observed that mononuclear phagocytes migrate through capillary and venule walls into the islet parenchyma, where they differentiate into tissue macrophages. It was only later (step 3) that these macrophages acquired novel properties, typical of their “activated state” and started to phagocytose islet beta-cell debris. These data suggest that during the pre-infiltration and early insulitis the mononuclear phagocyte system plays a key role in the onset of LDS diabetes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01605977
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  • 15
    Digitale Medien
    Digitale Medien
    Malignant rhabdoid tumour of the uterus: an immunohistochemical and ultrastructural study (1992)
    Springer
    Virchows Archiv 420 (1992), S. 459-462 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Malignant rhabdoid tumour ; Uterus ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Malignant rhabdoid tumours (MRTs) are highly aggressive neoplasms which most frequently occur in the kidney of young children. Several cases of primary MRT occurring in extra-renal sites have been reported, particularly in the soft tissues. We report a case of primary MRT of the uterus, a very rare site for this neoplasm, with morphological, immunohistochemical and ultrastructural features corresponding to restrictive morphological criteria for MRT. The possible differential diagnoses were considered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600519
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  • 16
    Digitale Medien
    Digitale Medien
    Effects of combined renovascular hypertension and diabetes mellitus on myocardial cells, non-vascular interstitium and capillaries: a stereological study on rat hearts (1992)
    Springer
    Virchows Archiv 420 (1992), S. 499-506 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Diabetes mellitus ; Renovascular hypertension ; Myocardium ; Stereology ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effects of combined renovascular hypertension and diabetes mellitus on the rat heart were investigated in order to detect possible synergistic effects of the two conditions. Hypertensive diabetic and hypertensive non-diabetic animals were compared to diabetic and non-diabetic controls. Hypertension was established for 12 weeks by a surgical stenosis of the left renal artery; diabetes mellitus was maintained for 8 weeks by a single intraperitoneal injection of 60 mg/kg streptozotocin. Light microscopic stereology did not reveal significant divergences between diabetic hypertensives and non-diabetic hypertensives. Hypertension induced a focal perivascular and interstitial fibrosis with increased volume densities of non-vascular interstitium and fibrosis (P〈0.001). Capillary density (QA) was decreased in transverse sections (P〈0.01) and increased in longitudinal sections (P〈0.01). This indicates a three-dimensional remodelling of the capillary bed with an increased number of obliquely running capillaries. At least the length density (LV) of capillaries (mm/mm3) tends to be normalized in long-term renovascular hypertension. At the ultrastructural level, a synergism of hypertension and diabetes mellitus was observed: the volume ratio of mitochondria to myofibrils was significantly decreased in hypertensive diabetics, but not in non-diabetic hypertensives or in diabetics. This may enhance the risk of cardiac deterioration. We conclude that the primary target of the synergistic damage in hypertensive diabetic heart muscle disease is the myocardial cell and not the cardiac interstitium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600254
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  • 17
    Digitale Medien
    Digitale Medien
    Electron microscopic study of paired helical filaments and cerebral amyloid using a novel en bloc silver staining method (1992)
    Springer
    Virchows Archiv 420 (1992), S. 519-525 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Silver staining ; Paired helical filaments ; Cerebral amyloid ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A one step en bloc silver staining method which was originally established to study nucleolar organizer regions has been applied for the demonstration of both paired helical filaments (PHF) and extracellular cerebral amyloids in semi-thin sections and at the electron microscopic level. The three forms of PHF can be visualized: (1) neurofibrillary tangles are shown in all stages from first appearance in form of intracellular patches of PHF to severely degenerated shadow-like “ghost” tangles; (2) neuropil threads are distinctly stained in great numbers; and (3) PHF are easily detected as neuritic components in amyloid plaques. All forms of fibrillar extracellular amyloid structures, i.e. “diffuse”, “classical” and “burnt out” plaques, are well demonstrated; congophilic angiopathy reveals amyloid preferentially in arteries and arterioles of the leptomeninges and cortex ranging from small circumscribed patches to large circumferential amounts with occasional plaque-like condensations or broad loose accumulations of amyloid; perivascular cuffs and laminar subpial deposits of amyloid are stained as well. At the electron microscopic level all lesions are clearly visible in non uranyl/lead-stained specimens, characterized by varying numbers of silver grains on a pale background. The detailed demonstration of structures in archival material, which had been stored in paraffin and re-embedded for electron microscopy, is due to the demonstration of argyrophilic structures by the protective colloidal developer of gelatin and formic acid and to the proteolytic resistance of insoluble PHF and extracellular amyloids in plaques and congophilic angiopathy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600257
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  • 18
    Digitale Medien
    Digitale Medien
    Malignant paraganglioma of the uterus (1992)
    Springer
    Virchows Archiv 420 (1992), S. 453-457 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Uterus ; Paraganglioma ; Intracytoplasmic hyaline globules ; Immunohistochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We report a malignant uterine paraganglioma in a 40-year-old female, who died 7 months after the initial diagnosis. On light microscopy the tumour showed a typicalzellballen pattern as well as a pronounced cellular pleomorphism. In many tumour cells hyaline globules were demonstrated within the cytoplasm. Immunohistochemically the lesion was characterized by the presence of neuron-specific enolase, protein gene product 9.5 and synaptophysin, and electron microscopically by the occurrence of neurosecretory granules.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600518
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  • 19
    Digitale Medien
    Digitale Medien
    Cytoskeletal filaments in the smooth muscle cells of uterine leiomyomata and myometrium: An ultrastructural and immunohistochemical analysis (1992)
    Springer
    Virchows Archiv 420 (1992), S. 51-58 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Leiomyoma ; Myometrium ; Cytoskeleton ; Ultrastructure ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The filamentous components of the cytoskeleton in smooth muscle cells of leiomyomata and normal myometrium were studied by immunohistochemistry and electron microscopy. Fourteen patients hysterectomised for non-malignant disease provided leiomyomata of conventional histological type and histologically normal myometrium: four samples of fetal myometrium were studied by immunohistochemistry alone. All samples of leiomyoma and myometrium were strongly positive for α-smooth muscle actin and desmin, the latter often as paranuclear columns or granules. Vimentin was also stained in most samples but less intensely, while cytokeratin stained in about half the samples with an intensity comparable to that of vimentin. By electron microscopy, myofilaments with focal densities were abundant in both normal myometrium and leiomyomata. Intermediate filaments corresponding to the desmin and vimentin demonstrated by immunohistochemistry were also recognised in a variety of architectural arrangements. At one extreme, comparatively small numbers of filaments were loosely distributed around membranous organelles; at the other, filaments formed conspicuous aggregates, largely excluding other organelles and corresponding to the paranuclear granules seen by immunohistochemistry. A comparison of these findings with those of the literature and comments on the possible significance and origin of these aggregates are provided.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01605984
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  • 20
    Digitale Medien
    Digitale Medien
    Granular cell tumour of the breast (1992)
    Springer
    Virchows Archiv 420 (1992), S. 219-226 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Breast ; Granular cell tumour ; Mammography ; Ultrastructure ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Eight cases of benign granular cell tumour of the breast are reported. Seven patients were women and one was male. The age at the time of the excision ranged from 17 to 73 (average 40.1) years. All tumours were positive for S-100 protein and negative for keratin, myoglobin and gross cystic disease fluid protein. In two cases ultrastructural studies revealed findings identical to those in the previously reported cases of granular cell tumours. None of these cases were diagnosed preoperatively. In six cases the clinical and mammographic findings, and in one case the frozen section, led to an erroneous diagnosis of malignancy. The clinico-pathological features of the cases are delineated in order to draw attention to a benign condition which closely simulates malignancy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600274
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  • 21
    Digitale Medien
    Digitale Medien
    Ultrastructural anomalies in the fetal small intestine indicate that fetal swallowing is important for normal development: an experimental study (1992)
    Springer
    Virchows Archiv 420 (1992), S. 305-312 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Fetus ; Small intestine ; Ultrastructure ; Malnutrition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Fetal swallowing is established early in development and if fetal ingestion is prevented, the gastrointestinal (GI) tract fails to grow normally. In this article we describe the ultrastructural features of GI tissues developing in the absence of swallowing, in the fetal sheep. We have noted a number of defects in enterocyte morphology. These include abnormal or absence of microvilli, inappropriate cell extrusion, glycogen accumulation and altered lysosomal morphology. Many of these changes resemble those seen in malnourished infants. It is possible that fetal ingestion provides a significant source of nutrients, ensuring adequate GI tract growth in utero, in addition to specific growth factors which may be present in ingested fluid.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600209
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  • 22
    Digitale Medien
    Digitale Medien
    A histopathological and ultrastructural study of eccrine porocarcinoma with special reference to its subtypes (1992)
    Springer
    Virchows Archiv 420 (1992), S. 395-401 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Eccrine porocarcinoma ; Ultrastructure ; Giant cell ; Elastic fibre ; Globular filamentous body
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Five cases of eccrine porocarcinoma were studied by light and electron microscopy. Histopathologically, these could be classified into two types; the common and the giant cell type. The common type was characterized by almost uniform medium-sized cuboidal tumour cells and a formation of well-developed intracytoplasmic lumina. A broad diversity of histopathological and ultrastructural features was seen in these tumours. The tumours of the giant cell type consisted of mononu-clear polygonal cells and bizarre giant cells. This type was considered to be an undifferentiated form of porocarcinoma.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600510
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  • 23
    Digitale Medien
    Digitale Medien
    Ultrastructural identification of neurofibrillary tangles in the spinal cords in Guamanian amyotrophic lateral sclerosis and parkinsonism-dementia complex on Guam (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 277-282 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Spinal cord neurofibrillary tangles ; Parkinsonism-dementia complex on Guam ; Guamanian amyotrophic lateral sclerosis ; Ultrastructure ; Immunoelectron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The immunohistochemical and ultrastructural characteristics of spinal cord neurofibrillary tangles (NFTs) were examined in Guamanian amyotrophic lateral sclerosis and in parkinisonism-dementia complex on Guam. The spinal cord NFTs reacted with antibodies to tau protein (tau-2), ubiqitin and paired helical filaments (PHFs). Ultrastructurally, the components of the NFTs were seen as randomly arranged fibrils which were often associated with osmiophilic granules; small bundle-like arrangements were also occasionally observed. Individual NFT fibrils appeared as straight fibrils with a diameter of approximately 15 nm and constricted fibrils with a periodicity of approximately 80 nm. Ultrastructural microscopic examination of specimens stained by the modified Bielschowsky method and with the antibodies revealed silver particles and the products of the tau, ubiquitin and PHF immunoreactions on the NFT fibrils. This is the first demonstration of the fine structure of the spinal cord NFTs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00296790
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  • 24
    Digitale Medien
    Digitale Medien
    Immunocytochemical and ultrastructural studies of eosinophilic granular bodies in astrocytic tumors (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 408-414 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Eosinophilic granular body ; Astrocytoma ; Ultrastructure ; Immunocytochemistry ; αB-crystallin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Eosinophilic granular bodies (EGBs) are studied immunocytochemically and ultrastructurally in a case of low-grade and a case of high-grade astrocytoma. EGBs are recognized as brightly eosinophilic round bodies of variable size in hematoxylin and eosin-stained sections. Immunocytochemically some EGBs are positive for antibodies raised against αB-crystallin, ubiquitin and glial fibrillary acidic protein with the staining patterns for each being different from one another. Ultrastructurally EGBs consist of membrane-bound round body of various diameter ranging from 50 nm to 20 μm. Small EGBs contain electron-dense homogeneous material with occasional myelin figures, while large EGBs contain small EGB-like structures within electron-dense homogeneous material or loose granular profiles. Our studies demonstrate (1) ultrastructural variety of EGB; (2) and αB-crystallin epitope in EGB; and (3) the presence of EGB in high-grade as well as low-grade astrocytoma.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00713533
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  • 25
    Digitale Medien
    Digitale Medien
    Occlusive microangiopathy by immunoglobulin (IgM-kappa) precipitation: pathogenetic relevance in paraneoplastic cryoglobulinemic neuropathy (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 423-426 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Peripheral neuropathy ; Cryoglobulinemia ; Immunohistochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Histological, immunohistochemical and ultrastructural sural nerve and skin biopsy findings in a case of cryoglobulinemia secondary to an IgM-kappa-producing non-Hodgkin lymphoma are described. The main finding was an occlusive microangiopathy present in both the sural nerve and the skin. Widespread cryoglobulin deposits of the proliferated vasa nervorum were associated with pronounced changes probably evoked by ischemia. Moderate perivascular inflammation, but no florid vasculitis was additionally present. Our observations indicate that occlusive microangiopathy by precipitated cryoglobulins may be a relevant pathogenetic factor in cryoglobulinemic peripheral neuropathy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00713536
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  • 26
    Digitale Medien
    Digitale Medien
    Ultrastructural studies of the cells forming amyloid in the cortical vessel wall in Alzheimer's disease (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 117-127 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Alzheimer disease ; Amyloid angiopathy ; Pericytes ; Microglia ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Ultrastructural studies of serial sections of the vessels with amyloid deposits in the brain cortex of patients with Alzheimer's disease showed that cells in the position of pericytes — perivascular cells - and perivascular microglial cells are producers of amyloid fibrils in the vascular wall. Three types of changes from normal are distinguishable in the vessel wall: (1) semicircular or circular thickening of vascular wall containing a large amount of amorphous material and various number of amyloid fibrils, (2) tuberous amyloid deposits containing both amorphous material and amyloid fibrils, some of the fibrils being arranged in strata and others arranged radially, and (3) amyloid star composed of a predominantly radial arrangement of bundles of amyloid fibrils and a less prominent amorphous component. A mixture of amorphous material and amyloid fibrils is present in cell membrane envaginations of perivascular cells, and occasionally perivascular microglial cells. Bundles of amyloid fibrils are found in altered cisternae of the endoplasmic reticulum and in the channels confluent with the infoldings of the plasma membrane of perivascular microglial cells. The amyloid deposition in the wall of the vessel causes degeneration of endothelial cells and the reduction of, and in some vessels obliteration of, the vessel lumen. In areas affected by amyloid angiopathy, extensive degeneration both of the neuropil and of neurons was observed. These changes were accompanied by astrogliosis. This study demonstrates similarities in amyloid formation in amyloid angiopathy and in β-amyloid plaques in the neuropil and suggests that cells of the mononuclear phagocyte system of the brain (perivascular cells and perivascular microglia) are engaged in amyloid fibril formation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00311383
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  • 27
    Digitale Medien
    Digitale Medien
    Presenile dementia with progressive supranuclear palsy tangles and Pick bodies: an unusual degenerative disorder involving the cerebral cortex, cerebral nuclei, and brain stem nuclei (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 128-134 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Progressive supranuclear palsy ; Neurofibrillary tangles ; Pick body ; Immunocytochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Degeneration of heterogeneous systems in the central nervous system, with widespread distribution of argyrophilic neuronal fibrillary inclusions, was found in a patient with presenile dementia. Atrophy was circumscribed in the frontal and temporal lobes. Neuronal loss was severe in the basal ganglia, subthalamic nucleus, and substantia nigra. Immunocytochemical study using anti-phosphorylated tau and anti-ubiquitin antibodies in conjunction with ultrastructural observations revealed two types of inclusions: neurofibrillary tangles (NFTs) of progressive supranuclear palsy (PSP) in the Edinger-Westphal nucleus, locus coeruleus, cerebellar dentate nucleus, inferior olivary nucleus, and posterior horn of the spinal cord; and Pick bodies (PBs) in the atrophied cerebral cortex and red nucleus. PSP-type NFTs and PBs have been demonstrated in a single case for the first time. Despite their pathognomonic significance in certain disorders, we suggest that these inclusions may reflect a form of cytoskeletal disorganization, which is not entirely restricted to a single disease entity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00311384
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  • 28
    Digitale Medien
    Digitale Medien
    Ultrastructural and immunohistochemical studies on ballooned cortical neurons in Creutzfeldt-Jakob disease: expression of αB-crystallin, ubiquitin and stress-response protein 27 (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 443-448 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Creutzfeldt-Jakob disease ; Ballooned neurons ; Ultrastructure ; αB-Crystallin ; Stress-response proteins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This report concerns ultrastructural and immunohistochemical studies on ballooned neurons of ten patients with Creutzfeldt-Jakob disease (CJD). While abundant ballooned neurons and severe white matter degeneration was seen in six Japanese cases, only occasional ballooned neurons and no white matter degeneration was observed in four cases from the files of Montefiore Medical Center. Ultrastructurally, the ballooned neurons contained granule-coated fibrils of 25 to 40 nm in width and 10-nm neurofilaments. The immunohistochemical studies revealed that most ballooned neurons expressed αB-crystallin, with deposits of reaction products observed in the cytoplasm. A similar intracellular staining pattern was also seen with the antibody to phosphorylated neurofilament proteins (pNFP). Although the proportion of stained ballooned neurons was less, a positive reaction was also observed with antibodies against ubiquitin, stress-response protein 27 (srp 27) and synptophysin, but not with an antibody to srp 72. Our findings suggest that expression of pNFP and synaptophysin by ballooned neurons may reflect axonal impairment and that the presence of αB-crystallin, srp 27 and ubiquitin may be related to the degenerative processes that neurons undergo in CJD.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227673
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  • 29
    Digitale Medien
    Digitale Medien
    Sural nerve immunoreactivity for nerve growth factor receptor in a case of localized hypertrophic neuropathy (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 547-553 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Localized hypertrophic neuropathy ; Electron microscopy ; Immunohistochemistry ; Nerve growth factor receptor ; Schwann cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Immunoreactivity for nerve growth factor receptor (NGFR) was examined using a monoclonal antibody against human NGFR in the sural nerve of a 24-year-old woman, affected by localized hypertrophic neuropathy (LHN). NGFR expression was correlated with electron microscopy and with immunoreactivity for S-100 protein, laminin, HLA-DR, HNK-1, P0 glycoprotein and neurofilament peptides. Our results indicate that in LHN most of whorl-forming cells are NGFR positive and S-100 protein or HLA-DR negative. These data along with the ultrastructural features suggest their origin from perineurium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00310035
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  • 30
    Digitale Medien
    Digitale Medien
    Colloid cysts of the third ventricle: ultrastructural features are compatible with endodermal derivation (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 605-612 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Colloid cyst ; Endoderm ; Respiratory epithelium ; Third ventricle ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The histogenesis of colloid cyst of the third ventricle remains unsettled. Ultrastructural and immunohistochemical analyses have suggested the following possible origins: (a) neuroepithelium, including paraphysis, ependyma, choroid plexus and tela chorioidea; and (b) endoderm, including respiratory and enteric epithelium. This report describes the ultrastructural features of the lining epithelium in four cases of colloid cyst. Six distinct cell types were recognized: (1) ciliated cells with occasional abnormal cilia; (2) non-ciliated cells with microvilli coated with granulofibrillary material; (3) goblet cells showing discharge of secretory granules; (4) basal cells with prominent tonofilaments and desmosomes; (5) basal-located cells with elongated electron-lucent cytoplasm and scattered membrane-bound dense-core granules (150–350 nm); and (6) small undifferentiated cells with scanty organelles. Junctional complexes were present in the former four cell types but absent in the latter two. The types of epithelial cells and their topographic distribution within the epithelium are both very similar to those of normal respiratory epithelium and to the lining epithelium of intraspinal bronchogenic cyst. The observations made in the present study are compatible with the hypothesis that colloid cysts of the third ventricle originate from the endoderm, most likely the respiratory epithelium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00299409
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  • 31
    Digitale Medien
    Digitale Medien
    Immunohistochemistry of cholinergic receptors (1992)
    Springer
    Anatomy and embryology 186 (1992), S. 407-429 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Acetylcholine receptors ; Immunocytochemistry ; Electron microscopy ; Human motor endplate ; Human cerebral cortex ; Neurodegenerative disorders
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Acetylcholine and its receptors are involved in a variety of important signal transduction processes. As shown here paradigmatically for the human neuromuscular junction and the cerebral cortex, acetylcholine receptors can be visualized immunohistochemically at the cellular and subcellular level under physiological and pathological conditions. At normal motor endplates nicotinic cholinoceptors are localized at the surface of the postsynaptic junctional folds. In myasthenic syndromes investigation of muscle biopsies enables the diagnosis of receptor deficiencies at the ultrastructural level. In normal cerebral cortex pyramidal neurons are equipped with both nicotinic and muscarinic acetylcholine receptors localized to postsynaptic densities. In neuropsychiatric diseases cholinoceptor expression can be monitored at the cellular level by quantititative assessment of immunolabeled cortical neurons.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185457
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  • 32
    Digitale Medien
    Digitale Medien
    Silver staining of the postacrosomal sheath during human spermiogenesis (1992)
    Springer
    Anatomy and embryology 185 (1992), S. 271-274 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Man ; Spermiogenesis ; Postacrosomal ; sheath ; Silver staining ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Applying the silver staining technique, it could be shown that in the early phase of spermiogenesis a layer of argyrophilic material accumulated at the base of the acrosomal vesicle and at the outer side of the nuclear envelope opposite that region, and, later, at the inner side of the plasma membrane near the base of the acrosomal vesicle. During further development of the postacrosomal region of the spermatozoon head, the argyrophilic material associated with the plasmalemma grew caudally to form the postacrosomal dense lamina, while the argyrophilic material associated with the nuclear envelope, staying the same size, shifted to the caudal end of the postacrosomal dense lamina to form the postnuclear band.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00211825
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  • 33
    Digitale Medien
    Digitale Medien
    Ultrastructural study of ascending projections to the lateral mammillary nucleus of the rat (1992)
    Springer
    Anatomy and embryology 185 (1992), S. 547-557 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Dorsal tegmental nucleus of Gudden ; Laterodorsal tegmental nucleus ; Synaptic organization ; Anterograde tracing study ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We examined the synaptic organization of ascending projections from the pars ventralis of the dorsal tegmental nucleus of Gudden (TDV) and the laterodorsal tegmental nucleus to the lateral mammillary nucleus (LM). The LM neuropil consists of terminals containing pleomorphic synaptic vesicles and forming symmetric synaptic contact, and terminals containing round synaptic vesicles and forming asymmetric synaptic contact. They make up 63% and 37%, respectively, of all axodendritic terminals. All axosomatic terminals contain pleomorphic vesicles and make symmetric contact. Following injection of WGA-HRP into the TDV, many anterogradely labeled terminals and retrogradely labeled cells are found in the LM. Labeled terminals contact mainly proximal (more than 2 μm diameter) and intermediate (1–2 μm diameter) dendrites. Serial ultrathin sections of the LM show that 55% of axosomatic terminals are labeled anterogradely. Following injection of WGA-HRP into the laterodorsal tegmental nucleus, many anterogradely labeled terminals are found in the LM, but no retrogradely labeled cells are present. Labeled terminals contact mainly distal (less than 1 μm diameter) and intermediate dendrites as well as somata. In the LM neurons, 46% of axosomatic terminals are labeled anterogradely. All labeled terminals from these nuclei contain pleomorphic vesicles and make symmetric synaptic contact. These results indicate that almost all axosomatic terminals come from the TDV and the laterodorsal tegmental nucleus, which send inhibitory inputs to the lateral mammillary nucleus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185614
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  • 34
    Digitale Medien
    Digitale Medien
    Neuronal autophagic vacuoles in experimental scrapie and Creutzfeldt-Jakob disease (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 134-139 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Scrapie ; Creutzfeldt-Jakob disease ; Neuronal autophagy ; Neuropathology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We report the presence of autophagic vacuoles (AV) in neuronal perikarya and neuronal processes of rodents with experimental scrapie and Creutzfeldt-Jakob disease. AV were composed of sequestrated cytoplasmic areas containing ribosomes and occasionally mitochondria and small secondary vacuoles. The formation of AV may contribute to neuronal degeneration and ultimately to neuronal loss.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00308472
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  • 35
    Digitale Medien
    Digitale Medien
    Ultrastructural features of spongiform encephalopathy transmitted to mice from three species of bovidae (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 559-569 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Neuronal autophagy ; Bovine spongiform encephalopathy ; Lysosomes ; Ultrastructure ; Vactiolation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructural neuropathology of mice experimentally inoculated with brain tissue of nyala (Tragelaphus angasi; subfamily Bovinae), or kudu (Tragelaphus strepsiceros; subfamily Bovinae) affected with spongiform encephalopathy was compared with that of mice inoculated with brain tissue from cows (Bos taurus: subfamily Bovinae) with bovine spongiform encephalopathy (BSE). As fresh brain tissue was not available for nyala or kudu, formalin-fixed tissues were used for transmission from these species. The effect of formalin fixation was compared with that of fresh brain in mice inoculated with fixed and unfixed brain tissue from cows with BSE. The nature and distribution of the pathological changes were similar irrespective of the source of inoculum or whether the inoculum was from fresh or previously fixed tissue. Vacuolation caused by loss of organelles and swelling was present in dendrites and axon terminals. Vacuoles were also seen as double-membrane-bound and single-membrane-bound structures within myelinated fibres, axon terminals and dendrites. Vacuoles are considered to have more than one morphogenesis but the structure of vacuoles in this study was nevertheless similar to previous descriptions of spongiform change in naturally occurring and experimental scrapie, Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker syndrome and kuru. Other features of the ultrastural pathology of the transmissible spongiform encephalopathies including dystrophic neurites and scrapie-associated particles or tubulovesicular bodies were also found in this study. Neuronal autophagy was a conspicuous finding. It is suggested that excess prion protein (PrP) accumulation, or accumulation of the scrapie-associated protease-resistant isoform of PrP, may lead to localised sequestration and phagocytosis of neuronal cytoplasm and ultimately to neuronal loss.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00304476
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  • 36
    Digitale Medien
    Digitale Medien
    Paired helical filaments in astrocytes: electron microscopy and immunohistochemistry in a case of atypical Alzheimer's disease (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 228-232 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Alzheimer's disease ; Astrocytes ; Electron microscopy ; Immunohistochemistry ; Paired helical filaments
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A 54-year-old man who had cerebellar ataxia and pseudobulbar palsy at the age of 29 years, and soon developed dementia, myoclonus and convulsions, died after about 20 years in a vegetative state. Histological examination of the extensively atrophic and devastated brain (680 g) revealed the almost total loss of cerebral cortical neurons associated with numerous β-protein amyloid plaques, many extracellular tangles and a large number of hypertrophic astrocytes, and prominent amyloid angiopathy. The astrocytes were frequently immunopositive for anti-human tau antibody (anti-htau) and anti-ubiquitin antibody (anti-ubi). Double immunostaining with anti-htau and anti-glial fibrillary acidic protein (GFAP) antibody clearly demonstrated htau-positive domains within the GFAP-positive perikarya/and processes of several astrocytes. Electron microscopy of the hippocampal CA1, which was completely devoid of pyramidal neurons, revealed, in astrocytes, abnormal filaments indistinguishable from the paired helical filaments (PHFs) seen in neurons. On immunoelectron microscopy, the filaments were observed to be labeled with anti-htau and anti-ubi, exhibiting the same immunohistochemical features as neuronal PHFs. This is the first demonstration of clearly constricted and both tau- and ubiquitin-positive PHFs in astrocytes, indicating that, in some special conditions like in our case, processes similar to those that attack neurons also affect astrocytes and ultimately make the latter form PHFs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00296783
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  • 37
    Digitale Medien
    Digitale Medien
    Retinal photoreceptor fine structure in the velvet cichlid (Astronotus ocellatus) (1992)
    Springer
    Anatomy and embryology 186 (1992), S. 363-370 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Retinal photoreceptors ; Electron microscopy ; Teleost ; Astronatus ocellatus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The structure and arrangement of the retinal photoreceptors of the velvet cichlid fish (Astronotus ocellatus) have been studied by light and electron microscopy. Rods, single cones and double (twin) cones are present. In the light-adapted state, rods are very tall cells that reach deep into the retinal epithelial (RPE) layer. The long outer segment is composed of discs of uniform diameter displaying one or two incisures. The rod inner segment shows a distal ellipsoid of mitochondria, and then narrows dramatically in the myoid region. Rod nuclei are electron dense and located deep in the outer nuclear layer. Rod synaptic spherules are small and show two to three invaginated synaptic sites as well as superficial synapses. Single cones are similar to the individual members of a double cone and all display a short tapering outer segment, a large ellipsoid of mitochondria and a myoid rich in rough endoplasmic reticulum, polysomes, Golgi zones and autophagic vacuoles. Double cones have extensive subsurface cisternae along their entire contiguous surfaces. Cone nuclei are large and vesicular and located close to or through the external limiting membrane. The synaptic pedicles of cones are larger, more electron lucent, and display more invaginated (ribbon) synapses as well as conventional (superficial) synaptic sites than do the rod spherules. Rod photoreceptors certainly undergo retinomotor movements and it is probable that cones do as well. In the light-adapted state the cone photoreceptors are arranged in a repeating square mosaic pattern with one single cone surrounded by four double (twin) cones.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185986
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  • 38
    Digitale Medien
    Digitale Medien
    Placental iron transfer regulation in the haemophagous region of the badger placenta: ultrastructural localization of ferritin in trophoblast and endothelial cells (1992)
    Springer
    Anatomy and embryology 185 (1992), S. 175-179 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Badger-placenta ; Ultrastructure ; Ferritin ; Iron transfer regulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The haemophagous region of the badger (Meles meles L.) placenta is involved in iron transfer, and maternal erythrocytes are the only source of iron for the fetus. This ultrastructural study provides morphological evidence of placental ferritin iron storage intervening if haem-iron uptake exceeds fetal needs. Such placental ferritin is assumed to play an active role in iron transfer regulation. In this paper we demonstrate that this regulatory process of iron transfer by storage in placental ferritin occurs on at least two levels: the cytotrophoblast and the fetal endothelium. The latter could then act as a final monitor in the transfer of iron into the fetal circulation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185919
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  • 39
    Digitale Medien
    Digitale Medien
    Intraventricular infusion of N-methyl-D-aspartate (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 630-637 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Dentrites ; Excitotoxicity ; Glutamate ; N-Methyl-d-aspartate ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This study documents the ultrastructural features of acute neuronal injury following N-methyl-d-aspartate (NMDA) receptor activation. NMDA (100 nmol/μl) or vehicle was infused over a 15-min period into the lateral ventricle of adult rats. After perfusion fixation, specimens demonstrating normal and abnormal patterns of vascular permeability to horserdish peroxidase were sampled for ultrastructural analysis. In NMDA-infused rats, brain regions exhibiting protein extravasation contained swollen dendritic profiles and abnormal neuronal perikarya. Although periventricular regions were most severely affected, parenchymal abnormalities were also detected in the cerebral cortex, septum, striatum, thalamus, hypothalamus and cerebellum. Mildly affected dendrites contained dark compact mitochondria, while in severely swollen dendrites mitochrondia were enlarged with ruptured cristae. Focal sites of plasma membrane disruption were also detected within swollen dendrites. Swollen neurons commonly displayed peripheral pallor and increased numbers of cytoplasmic vacuoles. Other neurons appeared dark and shrunken, some containing disrupted mitochrondria and pyknotic nuclei. Pretreatment with the NMDA antagonist MK-801 (2 mg/kg) attenuated the neuronal and dendritic alterations. In conditions where cerebrospinal fluid levels of glutamate are abnormally elevated, excessive NMDA receptor activation may lead to early vascular and neuronal complications which could work in concert to promote brain injury.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227740
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  • 40
    Digitale Medien
    Digitale Medien
    Intraventricular infusion of N-methyl-d-aspartate (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 621-629 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Blood-brain barrier ; Endothelium ; Excitotoxicity ; N-Methyl-d-aspartate ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The purpose of this study was to document the early cerebrovascular consequences of excessive N-methyl-d-aspartate (NMDA) receptor activation. Five microliters of NMDA (100 nmol/μl) or vehicle was infused over a 15-min period into the lateral ventricle of adult rats. The protein tracer horseradisch peroxidase (HRP) was injected intravenously for blood-brain bartier (BBB) studies. The intraventricular infusion of vehicle (n=5) caused no alterations in arterial blood pressure or microvascular damage away from the intraventicular probe tract. In contrast, NMDA infusion (n=8) led to a gradual increase in arterial blood pressure (mean 36 mm Hg). Multifocal regions of HRP extravasation were observed bilaterally throughout the neuraxis following NMDA infusion. Sites of BBB disruption and hemorrhage included brain regions bordering ventricular spaces. In addition, isolated foci of protein extravasation were commonly detected in the cerebral cortex, thalamus, basal forebrain, septum and cerebellum. Pretreatment with the noncompetitive NMDA antagonist MK-801 (2 mg/kg) substantially reduced the BBB responses to NMDA. However, microvascular abnormalities were seen in NMDA-infused rats where blood pressure elevations were inhibited by blood removal. In addition to neurons, cerebral blood vessels are also acutely affected by NMDA receptor activation. Blockage of NMDA receptor channels following brain injury may potentially provide protection by attenuating BBB breakdown and subsequent brain edema.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227739
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  • 41
    Digitale Medien
    Digitale Medien
    “Reducing body”-like inclusions in skeletal muscle in childhood-onset acid maltase deficiency (1992)
    Springer
    Acta neuropathologica 85 (1992), S. 111-115 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Muscle ; Ultrastructure ; Lysosome ; Metabolic disorder ; Glycogenosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Unusual inclusions with some of the features of “reducing bodies” were encountered in the skeletal muscle biopsy of a 2.5-year-old boy with childhoodonset acid maltase deficiency. The biopsy revealed a vacuolar myopathy with lysosomal storage of glycogen and eosinophilic refractile inclusions in myofibers, which appeared dark blue with the menadione-nitroblue tetrazolium reaction. The significance of the association of inclusions with reducing properties in the setting of acid maltase deficiency is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00304641
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  • 42
    Digitale Medien
    Digitale Medien
    Caudate nucleus pathology in Parkinson's disease: ultrastructural and biochemical findings in biopsy material (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 352-360 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Parkinson's disease ; Ultrastructure ; Catecholomines ; Trans-synaptic degeneration ; Axonal dystrophy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Ultrastructural and biochemical properties of caudate nucleus (CN) biopsies in two patients with advanced Parkinson's disease (PD) were compared with three CN specimens removed during surgery for intracranial tumors. An additional two specimens from neurologically intact patients (59 and 86 years old) were removed during autopsy (performed 3 and 4 h post mortem, respectively) for electron microscopic studies. Dopamine levels in PD were reduced to less than 15% of control values. Both PD patients showed frequent dystrophic neurites and transsynaptic degeneration of neurons and neuritic processes. These changes were not found in CN from the four control individuals. Only a few dystrophic neurites were noticed in one 67-year-old control patient. The development of neuroaxonal dystrophy in CN is consistent with a dying-back process, probably accompanying abnormalities of axonal transport in PD. Transsynaptic degeneration of neurons in CN very likely represents a morphological marker of disease severity. The occurrence of this change may account for the poor clinical response of patients with advanced PD to intracerebral implantation of dopaminergic tissues.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00713525
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  • 43
    Digitale Medien
    Digitale Medien
    Novel eosinophilic inclusion in astrocytes (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 659-663 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Eosinophilic inclusion ; Neuroglia ; Astrocyte ; Aicardi's syndrome ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Intracytoplasmic and brightly eosinophilic inclusions within neuroglias are reported in a patient with Aicardi's syndrome. Most inclusion-bearing neuroglias were protoplasmic astrocytes in the cerebral cortex. Compared with similar eosinophilic and intracytoplasmic inclusions in other studies using both light and electron microscopy, the inclusions in this report are regarded as being novel and not previously described. Ultrastructually, the inclusions were composed of electron-dense granules and amorphous substances, and were not surrounded by a limiting membrane. They were numerous in the cerebral cortex, especially in part of the microgyrus, but absent in the deep cerebral white matter, subcortical nuclei, brain stem and the cerebellum. Therefore, they may be closely associated with brain malformation and congenital astrocytic dysfunction. They also suggested a functional difference in protoplasmic astrocytes themselves, according to the differentiation of related gray matter.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00299417
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  • 44
    Digitale Medien
    Digitale Medien
    Morphological observations on the Harderian gland of the North American opossum (Didelphis virginiana) (1992)
    Springer
    Anatomy and embryology 186 (1992), S. 145-152 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Harderian gland ; Tubuloalveolar endpieces ; Serous endpieces ; Ultrastructure ; Opossum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The Harderian gland of the North American opossum (Didelphis virginiana) is large and well developed, despite the absence of a nictitating membrane in the adult of this species. The elongate glands are surrounded by a delicate connective tissue capsule from which thin septae extend, subdividing the gland into numerous lobules. The secretory units of the opossum Harderian gland are drained by a well defined but not extensive intralobular and interlobular duct system. Most of the secretory end pieces consist of tubuloalveolar units with widely dilated lumina filled with secretory product. Numerous intact lipid vesicles suspended within an amorphous material constitute the luminal contents. Cells lining the tubuloalveolar secretory endpieces are usually columnar in shape, and characterized by numerous lipid-containing secretory vesicles and aggregations of polytubular complexes 40–60 nm in diameter. In addition, these cells contain numerous large irregularly shaped mitochondria, whose matrix is of considerable electron density. Intralobular and interlobular ducts are lined by electron-lucent epithelial cells that lack both the lipid-containing vesicles and the large mitochondria, although typical smaller mitochondria are found scattered within the cytoplasm. Both secretory endpieces and ductal elements are invested by an abundance of myoepithelial cells. A second, smaller serous type of secretory unit may occur near the centre of some Harderian gland lobules. In these units secretory tubules and acini are compactly arranged surrounding a narrow lumen. Serous cells are pyramidal in shape and the cytoplasm is characterized by numerous electron-dense secretory granules and scattered profiles of rough endoplasmic reticulum. Basolateral cell membranes show extensive infoldings and intercellular canaliculi are present. The overall size of cells forming the serous secretory units is much less than that comprising the tubuloalveolar secretory endpieces.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00174952
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  • 45
    Digitale Medien
    Digitale Medien
    Immunocytochemical and ultrastructural studies of upper motor neurons in amyotrophic lateral sclerosis (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 518-524 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Amyotrophic lateral sclerosis ; Upper motor neurons ; Ultrastructure ; Neurofilament ; Ubiquitin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The pathological alterations in upper motor neurons were investigated in 27 cases of adult-onset sporadic amyotrophic lateral sclerosis (ALS). No signficant cytoskeletal alterations were found in the Betz cells of any of the cases except one, although cytoskeletal pathology was consistently present in lower motor neurons. The one case had severe circumscribed atrophy of the precentral gyrus and, microscopically, had argentophilic intracytoplasmic inclusions in Betz cells and other pyramidal neurons in the primary motor area as eell as in the lower motor neurons. Immunocytochemically these inclusions contained the epitope of phosphorylated neurofilament and ubiquitin and ultrastructurally consisted of granule-associated filaments with neurofilaments. This is the first demonstration of alterations of cytoskeleton and ubiquitination in the giant cells of Betz, an established subset of upper motor neurons in ALS. Thus, although uncommon, cytoskeletal changes can be found in upper motor neurons in some ALS cases.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00310029
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  • 46
    Digitale Medien
    Digitale Medien
    Primary leptomeningeal glioma: ultrastructural and laminin immunohistochemical studies (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 538-542 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Primary leptomeningeal glioma ; Ultrastructure ; Basal lamina ; Laminin ; Heterotopic glial tissue
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We studied a case of primary leptomeningeal glioma (PLG) on the left parietal lobe of a 74-year-old woman and compared the tissue with heterotopic glial tissue from another case. The PLG tumor consisted of spindle-shaped cells with marked nuclear atypism, which tended to be arranged in a fascicular pattern, and the majority of its cells were positive for glial fibrillary acidic protein. Ultrastructural examination demonstrated that most of the tumor cells contained intermediate filaments and often junctional complexes were present on their plasma membranes. Frequently, basal lamina-like structures surrounding the tumor, cell surfaces were observed. Laminin immunohistochemistry clearly demonstrated a fine network of linear positive staining around the cytoplasm and processes of the tumor cells. The ultrastructure of the heterotopic glial tissue consisted of many astrocytes partially surrounded by basal lamina. These findings strongly suggest that PLG is a distinct tumor, which arises from the heterotopic astrocytes within the subarachnoid space.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00310033
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  • 47
    Digitale Medien
    Digitale Medien
    Morphological findings on peripheral nerve biopsies in 15 patients with human immunodeficiency virus infection (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 618-623 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Peripheral nerve biopsy ; HIV infection ; Ultrastructure ; in situ hybridization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A peripheral nerve biopsy was performed in 15 patients with human immunodeficiency virus (HIV) infection and polyneuropathy. Two cases [1 asymptomatic, 1 AIDS-related complex (ARC)] presented with chronic inflammatory demyelinating polyneuropathy; there was 1 case (asymptomatic) of mononeuropathy multiplex and 12 cases (1 asymptomatic, 1 ARC, 10 AIDS) with distal symmetrical polyneuropathy. Epi- or endoneurial microvasculitis was observed in 6 cases. Electron microscopy showed that nerve fiber lesions were mainly axonal. Severe segmental demyelination was also present in both cases of chronic inflammatory demyelinating polyneuropathy, with characteristic features of active demyelination in one. Numerous plasmacytoid cells were found in the endoneurium in 4 patients. Tubuloreticular inclusions were present in endothelial cells in the 10 cases with AIDS but absent in the other patients. Direct immunopathological examination with anti-immunoglobulin sera was negative in all cases. HIV was evidenced by in situ hybridization in 2 AIDS patients; no Epstein-Barr virus or cytomegalovirus was detected.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00299411
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  • 48
    Digitale Medien
    Digitale Medien
    Ultrastructure of the microglia that phagocytose amyloid and the microglia that produce β-amyloid fibrils (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 225-233 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Alzheimer's disease ; Tissue culture ; Microglia ; Amyloid ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The function of microglia associated with β-amyloid deposits still remains a controversial issue. On the basis of recent ultrastructural data, microglia were postulated to be cells that form amyloid fibrils, not phagocytes that remove amyloid deposits. In this electron microscopic study, we examined the ability of microglia to ingest and digest exogenous amyloid fibrils in vitro. We demonstrate that amyloid fibrils are ingested by cultured microglial cells and collected and stored in phagosomes. The ingested, nondegraded amyloid remains within phagosomes for up to 20 days, suggesting a very limited effectiveness of microglia in degrading β-amyloid fibrils. On the other hand, we showed that in microglial cells of classical plaques in brain cortex of patients with Alzheimer's disease, amyloid fibrils appear first in altered endoplasmic reticulum and deep infoldings of cell membranes. These differences in intracellular distribution of amyloid fibrils in microglial cells support our observations that microglial cells associated with amyloid plaques are engaged in production of amyloid, but not in phagocytosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227813
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  • 49
    Digitale Medien
    Digitale Medien
    Tubulovesicular structures in Creutzfeldt-Jakob disease (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 238-243 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Creutzfeldt ; Jakob disease ; Tubulovesicular structures ; Prion diseases ; Ultrastructure ; Transmissible spongiform encephalopathies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary By electron microscopy tubulovesicular structures (TVS) have been consistently observed in brain tissue of transmissible spongiform encephalopathies such as natural and experimental scrapie, bovine spongiform encephalopathy and experimentally induced, but not naturally occurring, Creutzfeldt-Jakob disease (CJD). For the first time we report here the presence of TVS in human brains with CJD as detected by transmission electron microscopy. TVS were observed in all three CJD specimens (two biopsies, one autopsy), but they were rare and were found only in one or two location(s) per grid. TVS were seen in distended pre- and postsynaptic terminals and measured approximately 35 nm in diameter; they were smaller and of higher electron density than synaptic vesicles. Their occurrence in all types of transmissible spongiform encephalopathies irrespective of the affected host and the strain of the infectious agent suggests their biological significance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227815
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  • 50
    Digitale Medien
    Digitale Medien
    Increased iron content in the putamen of patients with striatonigral degeneration (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 328-330 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Striatonigral degeneration ; Putaminal pigment ; Iron ; Atomic absorption spectroscopy ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We measured the total content of iron, cooper, zinc and manganese in the putamen of four patients with striatonigral degeneration (SND) and age-and gender-matched normal controls. The iron content in the SND patients was five times greater than in the controls. Electron microscopic histochemistry revealed the iron reaction products in the pigments showing a triphasic pattern of coarse, electron-dense globules, fine granular and fibrillary materials, and lamellated structures. These findings suggest that increased iron deposition may be related to pigment formation in the putament of SND.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227827
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  • 51
    Digitale Medien
    Digitale Medien
    Cerebral granular cell tumors: report of a case and a note on their nature and expected behavior (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 680-685 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Histiocytic markers ; Astrocytoma ; Electron microscopy ; Glial fibrillary acidic protein ; Granular cell tumor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A case of cerebral granular cell tumor (GCT) is reported. Histologically, the growth was composed of benign astrocytes, granular cells and transitional forms between both elements. Glial fibrillary acidic protein was detected in the glial component and, to a lesser extent, in the granular cells. Alpha-1-antichymotrypsin was demonstrated in the latter component only. Ultrastructural study also supported the evidence that neoplastic astrocytes became granular cells. The survey of the literature and our own results suggest that GCTs in this particular location, even when histologically benign, seem to have a worse prognosis than the low-grade supratentorial astrocytomas.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227746
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  • 52
    Digitale Medien
    Digitale Medien
    Morphometrical variations of prolactin cells in response to prolonged and systemic administration of Met-enkephalin in female rats (1992)
    Springer
    Anatomy and embryology 186 (1992), S. 99-105 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Prolactin cell ; Met-enkephalin ; Immunocytochemistry ; Ultrastructure ; Morphometr ; Rat(Sprague-Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A stimulatory effect on prolactin secretion had been describe after acute and systemic administration of met-enkephalin, but the effects of this opioid after chronic administration has not been reported, and the response of mammotroph cells is not clear. As a complement to previous studies, a morphometric analysis (light and electron microscopy) was carried out on prolactin cells from female rats treated chronically with met-enkephalin. Clear features of cellular hyperactivity appeared after chronic and systemic administration of the opioid, and these persisted for two weeks. The changes consisted in increases of cellular, cytoplasmic and nuclear areas, volume and surface densities of the Golgi complex and rough endoplasmic reticulum, as well as the numbers of exocytotic figures. These morphological alterations were paralleled by an increase in serum prolactin levels as detected by RIA. It is concluded that the increase in the synthesis and secretory activity of prolactin cells following chronic and systemic administration of met-enkephalin is very similar to those observed after acute and intraventricular administration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00710406
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  • 53
    Digitale Medien
    Digitale Medien
    Retinal pigment epithelial fine structure in the velvet cichlid (Astronotus ocellatus) (1992)
    Springer
    Anatomy and embryology 186 (1992), S. 371-377 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Retinal pigment epithelium (RPE) ; Electron microscopy ; Teleost ; Astronatus ocellatus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The morphology of the retinal pigment epithelium (RPE), choriocapillaris and Bruch's membrane (complexus basalis) have been studied by light and electron microscopy in the velvet cichlid (Astronotus ocellatus). The RPE is composed of a single layer of large columnar cells. The basal (scleral) border of these cells is minimally infolded, whereas the apical (vitreal) surface displays numerous pigment-laden processes which in light-adaptation surround both rod and cone outer segments. Laterally the RPE cells are joined by a series of basally located tight junctions. Wandering phagocytes are a constant feature within this epithelial membrane. The RPE cells display a large, vesicular nucleus, numerous mitochondria, much smooth endoplasmic reticulum, polysomes, myeloid bodies, phagosomes and melanosomes. Rough endoplasmic reticulum is relatively scarce within these cells. Although only light-adapted specimens were examined, it is thought that the melanosomes are capable of extensive retinomotor movement. The endothelium of the choriocapillaris facing Bruch's membrane is typically very thin but shows few fenestrations. Bruch's membrane is typical of other teleost species in that it is composed of only three layers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185987
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  • 54
    Digitale Medien
    Digitale Medien
    The cellular network of interstitial cells associated with the deep muscular plexus of the guinea pig small intestine (1992)
    Springer
    Anatomy and embryology 186 (1992), S. 519-527 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Intestine ; Interstitial cells ; Innervation ; Electron microscopy ; Guinea pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Systematic examination using electron microscopic montages and serial sections has demonstrated that three types of interstitial cell, namely gap junction-rich cells, glycogen-rich cells and fibroblast-like cells, are densely located along the whole extent of the deep muscular plexus of the guinea pig small intestine. They tend to be distributed in an alternating fashion in the cellular network, connected with muscle cells of the outer, circular layer by means of gap junctions. These three types of interstitial cell show close relations to two types of nerve varicosity: one type is characterized by clear round vesicles with diameters of about 50 nm, and the other by flattened vesicles measuring about 35 nm by 70 nm. Electron-dense patches have been observed at the cytoplasmic side of the axonal membranes. Muscle cells of both inner and outer circular layers also show close relations to these two types of nerve varicosity. These morphological features are discussed with the implication that they may have some regulatory role in intestinal movement.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00186974
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  • 55
    Digitale Medien
    Digitale Medien
    Electron microscopic investigations on the growing tip of nerve fibres in the developing distal forelimb of the mouse (1992)
    Springer
    Anatomy and embryology 185 (1992), S. 201-206 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Development ; Mouse ; Peripheral nerves ; Schwann cells ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The distal course of the sensory nerve fibres on the palmar side of the hand of 12-day-old mouse embryos was followed by serial ultrathin cross-sections of conventionally fixed tissue. Small nerves fibres are to be found in the space between the layer of the cutaneous blood vessels and the epidermis. A special arrangement of the tissue which is traversed by the nerve fibres is not visible. In most cases the nerve fibres are in intimate contact with fibroblasts. More distally the nerve fibres consist only of one axon encircled by a Schwann cell. The sheath of the Schwann cell decreases gradually, and finally disappears completely. The distal tips of the naked axons are a few μm ahead. In some cases they are considerably enlarged and contain only a fine fuzzy material without special cell organelles. Other axons may end in a more finger-like fashion, and contain also in the naked parts many cell organelles. Also the naked axons contact fibroblasts over long ranges. Collagen was not found aligned to the distal nerve fibres.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185922
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  • 56
    Digitale Medien
    Digitale Medien
    Light and electron microscopic morphology of the temporomandibular joint in growing and mature crab-eating monkeys (Macaca fascicularis): the condylar calcified cartilage (1992)
    Springer
    Anatomy and embryology 185 (1992), S. 189-199 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Mandibular condyle ; Calcified cartilage ; Ultrastructure ; Maturation ; Macaca fascicularis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In an attempt to show maturational alterations in the calcified cartilage, mandibular condyles of four growing and four adult male monkeys (Macaca fascicularis) were studied using light microscopy as well as transmission and scanning electron microscopy. All specimens were initially fixed by perfusion in the presence of ruthenium red. For examination of the hard tissue surfaces in the scanning electron microscope, uncalcified tissues were removed with sodium hypochlorite. In growing animals, almost the entire hard tissue surface in the joint region of the condyle was formed by calcified cartilage, while in adult animals, calcified cartilage was confined to load-bearing regions. In growing animals, the appearance of the calcified cartilage surface suggested a continuously advancing mineralizing front similar to that seen in the epiphyseal plate. Chondrocytes mostly exhibited a terminal stage of hypertrophy, and seemed to die and get lost through vascular invasion and subsequent endochondral ossification. In adult animals, most of the calcified cartilage surface appeared comparatively stable, and resembled the tidemark of articular cartilage. Chondrocytes were usually small and appeared viable. However, on the adult condyles, there were always circumscribed islands where chondrocytes and the pattern of mineralization resembled those seen in growing animals. In these regions, prominent chondroclastic activity indicated extensive articular remodelling. These observations suggest that at the end of somatic growth, condylar calcified cartilage undergoes considerable maturation from a type reminiscent of hyaline growth cartilage to a type resembling articular cartilage. Concomitantly, chondrocytes appear to change their developmental program, in that they stop enlarging and lose their commitment to death. However, they may be able to retain, or switch back to, a more immature stage, in case there is need for extensive articular remodelling.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185921
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  • 57
    Digitale Medien
    Digitale Medien
    Effects of cepharanthine and minoxidil on proliferation, differentiation and keratinization of cultured cells from the murine hair apparatus (1992)
    Springer
    Archives of dermatological research 284 (1992), S. 290-296 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Cepharanthine ; Minoxidil ; Culture ; Hair cells ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effects of cepharanthine and minoxidil on proliferation, differentiation and keratinization of cultured cells from the murine hair apparatus were examined electron microscopically. Both cepharanthine and minoxidil stimulated cell proliferation and delayed initiation of differentiation and keratinization of the cultured cells. On day 6, most control cells (87%) cultured in a 0.03 mM calcium medium without cepharanthine and minoxidil were differentiated into several subpopulations corresponding to those of in vivo cell layers of the hair apparatus, while most of the cells cultured with cepharanthine (71%) or minoxidil (70%) were still immature. On day 13, the number of degenerated cells increased (63%) in the control culture, whereas in the culture treated with cepharanthine or minoxidil, cell degeneration scarcely occurred (5% and 8%, respectively). Differentiated cells having tonofilaments were often observed in the cepharanthine- and minoxidil-treated cultures (76% and 72%, respectively). Elevation of extracellular calcium up to 1.0 mM induced keratinization (34%) in the control culture on day 6, while no keratinized cells were observed in the cepharanthine- or minoxidil-treated culture. On day 13 keratinization similarly occurred in the cultures with cepharanthine (30%) or minoxidil (48%). These results show that both cepharanthine and minoxidil may directly influence proliferation, differentiation and keratinization of cultured cells from the hair apparatus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00372583
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  • 58
    Digitale Medien
    Digitale Medien
    Ultrastructural localization of actin in normal human skin (1992)
    Springer
    Archives of dermatological research 284 (1992), S. 242-245 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Immunogold ; Electron microscopy ; Human skin ; Actin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Normal human skin was embedded in Lowicryl K4M. Actin microfilaments were localized by applyinga postembedding immunogold technique using the monoclonal anti-actin antibody HHF35. Actin microfilaments are part of the cytoskeleton in muscle and nonmuscle cells. Together with myosin they produce contraction. The antibody labelled myofilaments in smooth muscle arrector pili cells, myoepithelial cells and pericytes. In sweat gland cells the microvilli system, a zone beneath the cytoplasma membrane correponding to the adhesion belt region, and apocrine decapitation formations showed labelling.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00375802
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  • 59
    Digitale Medien
    Digitale Medien
    Clinical, light and electron microscopic features of recessive ichthyosis congenita type III (1992)
    Springer
    Archives of dermatological research 284 (1992), S. 259-265 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Genodermatoses ; Ultrastructure ; Membrane structures ; Abnormal keratinosomes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The recessively inherited congenital ichthyoses have ultrastructural features which indicate abnormal epidermal lipid metabolism. The ultrastructural markers of the three recessive congenital ichthyosis groups are lipid droplets in horny layers (type I), cholesterol clefts (type II) and membrane structures (type III). We describe six patients from five families belonging to the last group. The variable clinical phenotype alone does not allow the delineation of this disease, but together with the ultrastructural characteristics the subtype is unequivocal. In addition to the membrane structures, half of the cases showed abnormal keratinosomes and vesicular complexes. Membrane-bound vacuoles and needle-like slits were exceptionally found. The onset of the ichthyosis was variable, in contrast to other patients described under the heading recessive congenital ichthyosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00372578
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  • 60
    Digitale Medien
    Digitale Medien
    Basal lamina-like material and hemidesmosome-like structures associated with dermal papilla cells in the normal human anagen hair follicle (1992)
    Springer
    Archives of dermatological research 284 (1992), S. 303-306 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Hair follicle ; Basal lamina ; Dermal papilla cells ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00372585
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  • 61
    Digitale Medien
    Digitale Medien
    Relationship between tissue reactions and morphological changes of the fungi in chromoblastomycosis: morphometry and electron microscopy (1992)
    Springer
    Archives of dermatological research 284 (1992), S. 95-99 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Chromoblastomycosis ; Host-fungus relationship ; Morphometry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary To investigate the histological distribution and the morphology of the fungi and the tissue reactions in chromoblastomycosis, especially in the process of trans-epidermal elimination, cutaneous lesions of two patients with this disease were studied morphometrically and ultrastructurally. In the dermis, most of the fungal elements appeared as sclerotic cells and their cell wall showed an irregular, worm-eaten leaf-like appearance; they seemed to be continuously attacked by polymorphonuclear neutrophils. The epidermis eliminated 10–20% of all the organisms in the skin lesions, and the hypha-forming activity tended to be higher in the epidermis than in the dermis. Ultrastructurally, basal keratinocytes facing the dermal abscess containing fungal elements frequently appeared as dark cells, suggesting an increased proliferation activity. Spinous keratinocytes facing intraepidermal microabscesses containing fungal elements showed an abnormal accumulation of tonofilaments and further early keratinization in the spinous cell layer. All of the morphological changes of the dermis and epidermis are regarded as defence reactions against the fungi existing in the skin lesions. There is a close relationship between tissue reactions and morphological changes of fungi in chromoblastomycosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00373377
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  • 62
    Digitale Medien
    Digitale Medien
    Increase in types IV and VI collagen in cherry haemangiomas (1992)
    Springer
    Archives of dermatological research 284 (1992), S. 275-282 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Cherry haemangioma ; Type IV collagen ; Type VI collagen ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The capillaries in cherry haemangiomas show perivascular hyalinized sheaths. In order to clarify the nature of this sheath material, the extracellular matrix of cherry haemangiomas from 20 normal volunteers (age range 30–64 years) was investigated using immunohistochemical and electronmicroscopical methods. Antibodies against collagen types III, IV and VI and laminin were used. Hyaluronic acid was visualized using the hyaluronic acid binding region of the cartilage proteoglycan as ligand. Electronmicroscopically, the sheaths contained multilaminated basement membrane-like material, collagen fibres 20–25 nm thick with a periodicity of 67 nm and broad-banded aggregates with a periodicity of 100 nm (zebra bodies or fibrous long-spacing fibres). Immunohistochemically, type IV collagen was stained throughout the whole sheath material. Staining for laminin was more confined to the endothelial side of the sheath. Intense staining for type III collagen and hyaluronic acid was found in the connective tissue of the subpapillary layer and between the cherry haemangioma capillaries. Much weaker staining for type III collagen and no staining for hyaluronic acid were found invariably in an area 4–10 Μm thick directly around the capillaries. Both sheath material and intercapillary connective tissue of the haemangiomas showed pronounced staining for collagen type VI. Immunogold staining revealed that type VI collagen was localized to microfibrils 5–6 nm thick and to the broad-banded aggregates with 100 nm periodicity. These findings further underline the assumption that the broad-banded aggregates consist of type VI collagen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00372581
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  • 63
    Digitale Medien
    Digitale Medien
    Electron-microscopic description of accretions occurring on tips of infected and non-infected central venous catheters (1992)
    Springer
    Intensive care medicine 18 (1992), S. 464-468 
    Details
    ISSN: 1432-1238
    Schlagwort(e): Catheter ; Electron microscopy ; Infection ; Adherence ; Candida albicans
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Objective The purpose of the study was do describe the architecture of accretions occurring on the tips of central venous catheters (CVC). Design A conservative procedure was used followed by two different techniques of electron microscopy Setting and patients the study included 19 catheters which have been used on intensive cared adults, and which were chosen among those of parallel 300 CVC study. Measurements and results CVC were considered sterile, contaminated, colonized or infected according to microbiological and clinical criteria. CVC were found to remain much cleaner than in past clescriptions. When present, accretions were located on the olive-shaped end, and displayed stratified structures with three types of material: amorphous material, thrombus components and inflammatory cells. Bacteria were not seen, even on culture positive CVC. Candida albicans was found on one CVC in the cytoplasm of ganulocytes, and made xio direct contact with the plastic surface. Conclusion This technique should contribute to the understanding of the pathobiology of CVC infection and provide information proving or precluding the involvement of microbial adherence to polymers in vivo.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01708582
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  • 64
    Digitale Medien
    Digitale Medien
    Calcium binding protein (calbindin D28k) immunoreactivity in the hamster superior colliculus: ultrastructure and lack of co-localization with GABA (1992)
    Springer
    Experimental brain research 89 (1992), S. 115-124 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Immunocytochemistry ; Visual pathways ; Electron microscopy ; Hamster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The expression of specific calcium binding proteins is being used increasingly as a potential neuroanatomical marker for neurons with similar functions. In this study, the distribution of calbindin D28k in the superior colliculus (SC) of adult hamsters was examined by light and electron microscopy. Calbindin immunoreactivity was prominent in specific regions and laminae of the SC throughout its rostrocaudal extent, and was found to label horizontal, vertical and stellate cell types. In addition, calbindin label highlighted “bridges” of neuronal processes in the intermediate layers. The most frequent calbindin-immunoreactive profiles seen in the electron microscope were dendrites, some of which were post-synaptic to apparent retinal ganglion cell axon terminals. Labelled axons and axon terminals were less frequently encountered. There was considerable overlap between the size distribution of calbindin D28k-immunoreactive neurons and that of GABA-immunoreactive or Nissl stained neurons in the SC. However, using a double fluorescent labelling technique, and examination of the tissue with confocal laser microscopy, no neurons were observed in the hamster SC that showed immunoreactivity for both calbindin and GABA. In this regard, the SC is similar to the mammalian lateral geniculate nucleus and the pretectum, but differs from the neocortex, where calbindin and GABA are colocalized. The demonstration in the SC, as well as other parts of the nervous system, of sub-populations of neurons that contain distinct calcium-binding proteins suggests that these neurons have different functional properties. Correlative studies may clarify the relevance of these cytoplasmic components as cell markers, as well as their different patterns of association with neurotransmitters and peptides.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00229008
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  • 65
    Digitale Medien
    Digitale Medien
    Early events during the establishment of the Gunnera/Nostoc symbiosis (1992)
    Springer
    Planta 188 (1992), S. 403-413 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Cyanobacterium ; Gunnera ; Infection process ; Nostoc ; Symbiosis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The symbiosis between Gunnera and Nostoc was reconstituted using G. chilensis Lam. and G. manicata Linden, respectively, and three different Nostoc strains. Six stages characterised by specific modifications in both the cyanobiont and the host were recognised during the infection process. Mucilage-secreting stem glands developed on the Gunnera stems independent of the presence of cyanobacteria (Stage I). Soon after addition of the Nostoc isolates to the plant apices, an abundant differentiation of motile hormogonia commenced. The cyanobacteria accumulated in the mucilage on the surface of the gland (Stage II), and the hormogonia then proceeded into the stem tissue through intercellular channels (Stage III). At the channel bases, Nostoc was detected between the cell walls of small, densely cytoplasmic Gunnera cells and also in elaborate folds of these (Stage IV). The Gunnera cell walls subsequently dissolved adjacent to the cyanobacteria and Nostoc entered the host cells (Stage V). Once the intracellular association was formed, a high proportion of the vegetative Nostoc cells differentiated into heterocysts (Stage VI). Nostoc changed from being rich in inclusions (particularly cyanophycin) while on the gland surface into a comparatively “non-storing” form during penetration and the early intracellular stages. Bacteria were numerous on the gland surface, fewer in the channels, and were never detected within the Gunnera cells, indicating the existence of specific recognition mechanisms discriminating between conceivable microsymbionts. Mechanisms behind mutual adaptations and interactions between the two symbionts are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00192808
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  • 66
    Digitale Medien
    Digitale Medien
    High-pressure freezing of soybean nodules leads to an improved preservation of ultrastructure (1992)
    Springer
    Planta 188 (1992), S. 155-163 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Bradyrhizobium ; Electron microscopy ; Glycine (root nodules) ; High-pressure freezing ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract High-pressure freezing of chemically untreated nodules of soybean (Glycine max (L.) Merr.), in sharp contrast to chemical fixation and prefixation, appears to preserve the ultrastructure close to the native state. This is supported by the observation that the peribacteroid membrane of high-pressure-frozen samples is tightly wrapped around the bacteroids, a finding that is fully consistent with the current views on the physiology of oxygen and metabolite transport between plant cytosol and bacteroids. In soybean root nodules, the plant tissue and the enclosed bacteria are so dissimilar that conventional aldehyde-fixation procedures are unable to preserve the overall native ultrastructure. This was demonstrated by high-pressure freezing of nodules that had been pre-fixed in glutaraldehyde at various buffer molalities: no buffer strength tested preserved all ultrastructural aspects that could be seen after high-pressure freezing of chemically untreated nodules.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00216809
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  • 67
    Digitale Medien
    Digitale Medien
    The microtubule cytoskeleton and the rounding of isolated generative cells ofNicotiana tabacum (1992)
    Springer
    Sexual plant reproduction 5 (1992), S. 64-71 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Generative cell ; Isolation ; Microtubules ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Upon squashing of the pollen grain, the isolated generative cell ofNicotiana tabacum looses its spindle shape to become spherical; this phenomenon is independent of the sucrose concentration used. The time necessary for this change can vary from 1 min (0% sucrose) to 20 min (30% sucrose). The microtubular cytoskeleton was studied by means of immunofluorescence and electron microscopy. Just after isolation, 5 to 15 clearly visible bundles in microtubules organized in a basket-like structure are present. After 15 min in medium with 15% sucrose, the microtubular cytoskeleton disappears, and a diffusely spread tubulin can be observed. Neither the addition of 10–20 μM taxol to the medium, nor the omission of Ca2+ to the medium has any effect on the changes in cell shape and loss of microtubular bundles after isolation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00714559
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  • 68
    Digitale Medien
    Digitale Medien
    Ultrastructure and microtubule organization of isolated generative cells ofAllemanda neriifolia at interphase and prophase (1992)
    Springer
    Sexual plant reproduction 5 (1992), S. 27-33 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Isolated generative cells ; Ultrastructure ; Microtubule ; Immunofluorescence microscopy ; Allemanda neriifolia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ultrastructure of isolated generative cells ofAllemanda neriifolia at interphase and prophase was studied. The microtubule organization of the isolated cells was also investigated by immunofluorescence microscopy with a monoclonal anti-α-tubulin. After the generative cells had been isolated from the growing pollen tubes by osmotic shock, most of the cells were at prophase and only a few were at interphase. The interphase cell is spindle shaped and contains an ellipsoidal nucleus. In addition to the usual organelles, the cytoplasm of the interphase cell contains numerous vesicles (each measuring 40–50 nm in diameter) and two sets of longitudinally oriented microtubule bundles — one in the cortical region and the other near the nucleus. Most of the prophase cells are spherical in shape. Based on the ultrastructure and the pattern of microtubule cytoskeleton organization three types of prophase cells can be recognized. (1) Early prophase cell, which contains the usual organelles, numerous vesicles, and a spherical nucleus with condensed chromosomes. Longitudinally oriented microtubule bundles can no longer be seen present in the early prophase cell. A new type of structure resembling a microtubule aggregate appears in the cytoplasm. (2) Mid prophase cell, which has a spherical nucleus containing chromosomes that appear more condensed than those seen in the early prophase cell. In addition to containing the usual organelles, the cytoplasm of this cell contains numerous apparently randomly oriented microtubules. Few vesicles are seen and microtubule aggregates are no longer present. (3) Late prophase cell, typified by the lack of a nuclear envelope. Consequently, the chromosomes become randomly scattered in the cytoplasm. Microtubules are still present and some become closely associated with the chromosomes. The changes in the ultrastructure and in the pattern of microtubule organization in the interphase and prophase cells are discussed in relation to the method of isolation of the generative cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00714555
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  • 69
    Digitale Medien
    Digitale Medien
    The formation of the generative cell in Polystachia pubescens (Orchidaceae) (1992)
    Springer
    Sexual plant reproduction 5 (1992), S. 131-137 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Pollen grain ; Generative cell ; Formation and detachment ; Ultrastructure ; Polystachia pubescens ; Orchidaceae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The formation and nature of the generative cell wall and the detachment mode of the generative cell from the intine in Polystachia pubescens were observed by LM and TEM. Vesicles evenly positioned within the phragmoplast fuse to form a cell plate that divides the microspore into the generative and vegetative cell. This cell plate consists of callose. Before the generative cell leaves the intine, however, the callose is completely resorbed and is not replaced by any other substance. The generative cell becomes detached from the intine by moving towards the centre of the pollen grain. A constriction formed thereby gives the generative cell a bulb-like appearance and leads ultimately to the generative cell being pinched off. Plasma-filled vesicles originating from the generative cell remain between the intine and the plasma membrane of the vegetative cell.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00194872
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  • 70
    Digitale Medien
    Digitale Medien
    Studies on the hepatotoxicity induced by bis (tributyltin) oxide (1992)
    Springer
    Archives of toxicology 66 (1992), S. 182-187 
    Details
    ISSN: 1432-0738
    Schlagwort(e): Bis(tributyltin) oxide ; Liver ; Electron microscopy ; X-ray microanalysis ; Biochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The toxic effects of bis (tributyltin) oxide (TBTO) on the rat liver were studied with an electron microscope and the accumulation sites of tin were determined with an X-ray microanalyzer. The activities of serum enzymes and the concentration of serum bilirubin were also analyzed. Male Wistar rats received an intramuscular injection of 0.5 ml/kg of TBTO. Marked swelling of the mitochondria appeared in the hepatocytes 4 h after injection of TBTO. Cytoplasmic vacuoles, which contained degenerated mitochondria, gradually increased in number in these hepatocytes. This in turn may have caused a decrease in the volume of hepatic cell cords and an enlargement of sinusoids in the entire hepatic lobule. However, fine structures of intrahepatic bile ducts were not altered. By X-ray microanalysis, tin peaks were preferentially obtained from swollen mitochondria of the hepatocytes. By polarographic analysis of the respiratory responses of mitochondria, it was demonstrated that rates of state 4 respiration and respiratory control ratio were significantly disturbed in TBTO-treated rats in comparison with those of controls. The activities of AST (aspartate aminotransferase) and ALT (alanine aminotransferase) were significantly increased after TBTO treatment, but those of ALP (alkaline phosphatase), LAP (leucine aminopeptidase) and total bilirubin were not changed. These results indicated that parenterally administered TBTO accumulated in the liver cell mitochondria and disturbed oxidative phosphorylation. Mitochondrial dysfunction might induce severe damage of the hepatocytes. Four days after injection of TBTO, hepatic structures and chemical indices were almost restored by the regeneration of hepatocytes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01974012
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  • 71
    Digitale Medien
    Digitale Medien
    Ultrastructural and immunohistochemical study of degenerate neurite-bearing ghost tangles (1992)
    Springer
    Journal of neurology 239 (1992), S. 191-194 
    Details
    ISSN: 1432-1459
    Schlagwort(e): Ghost tangles ; Degenerate neurites ; Astrocytes ; Senile plaques ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Some ghost tangles in the brains of Alzheimer patients were accompanied by many small argyrophilic structures which were electron microscopically confirmed to be degenerate neurites. In these ghost tangles, roughly dispersed 15 nm straight and occasional twisted tubules were penetrated by proliferated astrocytic processes. Immunohistochemically, these ghost tangles lost immunoreactivities to anti-NFT, -tau and -ubiquitin antibodies, but were thioflavine-S fluorescent, though antigenicity to β-protein was not proved. This similarity in composition of degenerate neurite-bearing ghost tangles to senile plaques might be induced by the amyloid nature of tubules, which probably provokes the reaction of neuropils.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00839138
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  • 72
    Digitale Medien
    Digitale Medien
    Electron microscopic examination of sporulation-deficient mutants of the fission yeast Schizosaccharomyces pombe (1992)
    Springer
    Archives of microbiology 158 (1992), S. 249-255 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Sporulation ; Meiosis ; Ultrastructure ; Spindle pole body ; Spo mutants ; Schizosaccharomyces pombe ; Fission yeast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A homothallic haploid strain of the fission yeast Schizosaccharomyces pombe initiates sexual reproduction (mating, meiosis and sporulation) in nitrogen-free sporulation medium. Cellular fine structures of eleven sporulation-deficient mutants (spo2, spo3, spo4, spo5, spo6, spo13, spo14, spo15, spo18, spo19 and spo20) of S. pombe in sporulation medium were examined by serial section-electron microscopy. The striking features of these spo mutants were: 1) the disappearance of the spindle pole bodies (SPBs) after the second meiotic division, and 2) the accumulation of unorganized structures. Based on histochemical staining, these structures were presumably unorganized spore wall precursors. In some mutants (spo3, spo5, spo6, spo19 and spo20), diploid zygotes contained four spore-like bodies which had walls similar to complete spore walls but failed to enclose any nuclei. After completion of the second meiotic division the nuclei were abnormally distributed in zygotic diploid cells. In the spo5, spo13, spo14, spo15 and spo19 mutants, the nuclei remained attached to each other. In spo5 and spo19, the inner membrane of the nuclear envelope was separated, but its outer membrane was shared by two sister nuclei. These observations suggest that the spo+ gene products play important roles in spatial and temporal organization of cellular structures during ascospore development.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00245240
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  • 73
    Digitale Medien
    Digitale Medien
    Frequency and structure of spinae on Chlorobium spp. (1992)
    Springer
    Archives of microbiology 157 (1992), S. 319-322 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Chlorobiaceae ; Spinae ; Chlorobium ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Several Chlorobium species have been observed to possess spinae. Spinae are non-prosthecate, helically wound, rigid structures that extend from the outer bacterial cell surface into the external environment. Spinae length was variable within and between Chlorobium species. Spinae width was fairly consistent within species but varied between species (39.4 ± 2.6 nm to 82.6 ± 8.0 nm). The number of spinae per cell varied. The spinae did not penetrate the bacterial cell envelope and were randomly located on the cell surface. Spinae were not geographically restricted. The observation of spinae on pure cultures of Chlorobium spp. maintained for 25–30 years suggests that spinae may be of significant use to the cell.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00248675
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  • 74
    Digitale Medien
    Digitale Medien
    Dynamics of PhiX174 protein E-mediated lysis of Escherichia coli (1992)
    Springer
    Archives of microbiology 157 (1992), S. 381-388 
    Details
    ISSN: 1432-072X
    Schlagwort(e): PhiX174 ; Bacterial lysis ; Escherichia coli ; Electron microscopy ; Membranes ; Cell envelope
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Expression of cloned gene E of bacteriophage PhiX174 induces lysis by formation of a transmembrane tunnel structure in the cell envelope of Escherichia coli. Ultrastructural studies of the location of the lysis tunnel indicate that it is preferentially located at the septum or at polar regions of the cell. Furthermore, the diameter and shape of individual tunnel structures vary greatly indicating that its structure is not rigid. Apparently, the contours of individual lysis tunnels are determined by enlarged meshes in the peptidoglycan net and the force produced at its orifice, by the outflow of cytoplasmic content. Once the tunnel is formed the driving force for the lysis process is the osmotic pressure difference between cytoplasm and medium. During the lysis process areas of the cytoplasmic membrane which are not tightly attached to the envelope are extended inward by the negative pressure produced during lysis. After cell lysis external medium can diffuse through the lysis tunnel filling the inner cell space of the still rigid bacterial ghosts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00248685
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  • 75
    Digitale Medien
    Digitale Medien
    Age-related immunoreactivity pattern in medulloblastoma (1992)
    Springer
    Child's nervous system 8 (1992), S. 326-331 
    Details
    ISSN: 1433-0350
    Schlagwort(e): Medulloblastomas ; Immunohistochemistry ; Cytokeratins ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Thirty-five paraffin-embedded medulloblastomas (19 from children and 16 from adults; 24 classic medulloblastomas, 10 desmoplastic medulloblastomas, 1 tumor with neuronal differentiation) were examined for reactions with antibodies against glial fibrillary acidic protein (GFAP), cytokeratins KL1 and MNF116, desmin, and vimentin. Only the tumor from the youngest patient, a 152-day-old boy, showed a positive immunoreaction for cytokeratins. Because of this age-related expression of cytokeratins in medulloblastomas primarily in very young children, cytokeratin positivity was interpreted as a sign of tumor immaturity. Five medulloblastomas showed scattered GFAP-positive reactive astrocytes and/or other positive, probably neoplastic, cells. Only two tumors showed GFAP immunoreactivity in unequivocally neoplastic cells. Of six tumors that reacted with vimentin, three showed strong reactivity throughout, one being the tumor from the 152-day-old boy. The remaining three demonstrated nests of vimentin-positive cells with weak or intense somatic immunoreactivity for vimentin. None of the 35 cases showed positivity for desmin, indicating that mesenchymal differentiation is restricted to the rare so-called medullomyoblastomas.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00296563
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  • 76
    Digitale Medien
    Digitale Medien
    Ultrastructural investigations of Arbutus unedo-Laccaria amethystea mycorrhiza synthesized in vitro (1992)
    Springer
    Trees 7 (1992), S. 40-47 
    Details
    ISSN: 1432-2285
    Schlagwort(e): Arbutus unedo ; Laccaria amethystea ; Mycorrhiza ; Synthesis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Anatomy and ultrastructure of the arbutoid mycorrhiza of Arbutus unedo-Laccaria amethystea from axenic culture are described. In comparison to non-inoculated roots, the rhizodermal cells of mycorrhizas are of greater volume, their nuclei are enlarged and show an irregular shape, plasmalemma and cytoplasm with mitochondria, plastids, endoplasmic reticulum and dictyosomes are increased. Several ontogenetical states are documented. The arbutoid mycorrhiza as a connecting link between ectomycorrhiza and ericoid mycorrhiza is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00225230
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  • 77
    Digitale Medien
    Digitale Medien
    The human placental transferrin receptor: Reconstitution into liposomes and electron microscopy (1992)
    Springer
    Bioscience reports 12 (1992), S. 471-482 
    Details
    ISSN: 1573-4935
    Schlagwort(e): Transferrin ; Receptor ; Isolation ; Reconstitution ; Liposomes ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Human transferrin receptor was isolated from Triton X-100 solubilized placental plasma membranes by a rapid one-step chromatographic procedure based on immunoadsorption of the receptortransferrin complex on anti-transferrin Sepharose and lectin-affinity on wheat germ agglutinin. Following exchange of Triton X-100 with CHAPS or n-octylglucoside, the purified receptor was incorporated into egg phosphatidylcholine liposomes upon, detergent removal by dialysis (lipid/protein ratio 15:1 to 45:1 (w/w) Reconstitution of the receptor was confirmed by trypsin cleavage to dissociate the large extracellular receptor domain from the liposomal membranes. Electron micrographs of the receptor-lipid recombinants negatively stained with sodium sillicotungstate, showed ographs of the receptor-lipid recombinants negatively stained with sodium sillicotungstate, showed that the receptor molecules distributed very inhomogeneously on the liposomes, most receptors being clustered. Single copies of the receptor were seen as elongate structures (5×10 nm) oriented with their long axis parallel to the liposome surface and separated from this by a 2–3 nm gap. This result provides evidence for a narrow connecting link between the globular extracellular receptor domain and the membrane spanning segment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01122035
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  • 78
    Digitale Medien
    Digitale Medien
    Exo-endocytosis in isolated peptidergic nerve terminals occurs in the sub-second range (1992)
    Springer
    Bioscience reports 12 (1992), S. 495-501 
    Details
    ISSN: 1573-4935
    Schlagwort(e): Electron microscopy ; secretion ; neuropeptides ; exocytosis ; endocytosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Exo- and endocytotic processes induced by depolarization of isolated neurosecretory nerve terminals show a close temporal correlation, which suggests a short time of integration of the neurosecretory granule membrane with the plasma membrane. In order to determine minimal time requirements for exocytosis-coupled endocytosis to occur, we have analyzed by electron microscopy uptake of horserdish peroxidase (HRP) as a fluid phase marker at the onset of depolarization. We have applied rapid mixing and sampling (quenched flow) to assess events in subsecond time peroids after stimulation. A significant number of labelled endocytotic vacuoles was observed during the first second of depolarization. This number then further increased by a factor of about 2 (within 5 s) and 4 (within 50s). Thus, as for exocytosis, the rate of endocytosis decreased considerably during prolonged stimulation. These data indicate i) that a substantial proportion of secretory granules undergoes exocytosis very shortly after stimulation, and ii) that, following exocytosis, the minimal time required for consecutive membrane retrieval is in the sub-second range.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01122037
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  • 79
    Digitale Medien
    Digitale Medien
    Effect of haloperidol and clozapine on the density of “perforated” synapses in caudate, nucleus accumbens, and medial prefrontal cortex (1992)
    Springer
    Psychopharmacology 106 (1992), S. 45-52 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Haloperidol ; Clozapine ; Perforated synapses ; Electron microscopy ; Tardive dyskinesia ; Extrapyramidal syndrome
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Perforated synapses, which contain a discontinuous density along the postsynaptic membrane, can increase or decrease in numbers following various behavioral and biochemical manipulations. We have previously established that 14-day treatment with haloperidol causes an increase in the number of perforated synapses within the caudate nucleus (dorsolateral region) but not the nucleus accumbens (Meshul and Casey 1989). This effect was reversed if the animals were withdrawn from the drug for an equivalent period of time. We have now further examined the effects of haloperidol administration, which is associated with a high incidence of extrapyramidal side effects (EPS) and tardive dyskinesia (TD), and assessed the effects of clozapine, which appears to have a lower potential for inducing EPS and TD. Administration of haloperidol for 2 weeks significantly increased the percentage of perforated synapses in the caudate, but not in the nucleus accumbens or layer VI of medial prefrontal cortex (MPCx). There was an increase in specific [125I]epidepride binding to D-2 receptors in the caudate nucleus and MPCx following haloperidol. Administration of clozapine for 2 weeks did not affect the percentage of perforated synapses in any of the three dopamine (DA)-rich regions that were examined. There was an increase in specific [3H]SCH 23390 binding to D-1 receptors and in specific [125I]epidepride binding to D-2 receptors only within MPCx following clozapine. The absence of any change in the density of perforated synapses within the dorsolateral caudate nucleus following clozapine correlates with: 1) the lack of effect on specific DA receptor binding or down regulation of serotonin (5-HT2) receptors (as reported by others), or 2) the inability in clozapine-treated animals to depolarize block substantia nigra (A9) DA neurons. These results may be related to the low incidence of EPS and TD observed with clozapine.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02253587
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  • 80
    Digitale Medien
    Digitale Medien
    Immunocytochemical and electron-microscopic study of the elasmobranch nucleus sacci vasculosi (1992)
    Springer
    Cell & tissue research 270 (1992), S. 395-404 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Nucleus sacci vasculosi ; Ultrastructure ; Immunocytochemistry ; Hypothalamus ; Tuberculum posterius ; Scyliorhinus caniculus, Raja undulata (Elasmobranchii)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The elasmobranch nucleus sacci vasculosi was studied by means of electron microscopy (in the dogfish) and immunocytochemistry (in the dogfish and the skate) by using antibodies against tyrosine hydroxylase, alpha-melanocyte-stimulating hormone, somatostatin, serotonin, and substance P. Ultrastructural study of the dogfish nucleus sacci vasculosi shows the presence of medium-sized cells that possess numerous mitochondria but that have no dense-core vesicles in the cytoplasm or in cell processes. Fibres of the conspicuous tractus sacci vasculosi have a beaded appearance and form conventional synapses with dendrites and cell perikarya of the nucleus sacci vasculosi. The perikarya of this hypothalamic nucleus were not immunoreactive to any of the antibodies tested, and fibres immunopositive to tyrosine hydroxylase, alpha-melanocyte-stimulating hormone, somatostatin, serotonin, and substance P were scarce within this nucleus, in both the dogfish and the skate. Dorsal to the nucleus sacci vasculosi, there are numerous positive neuronal processes in addition to many small neurons that show immunoreactivity to alpha-melanocyte-stimulating hormone, somatostatin and tyrosine hydroxylase. Two types of neuron occur in this dorsal region, displaying dense-core vesicles of either 100–160 nm or 60–100 nm diameter in their cytoplasm; they were identified as peptide-containing and monoamine-containing neurons, respectively. The neuropil of this region has a significantly different ultrastructure from that of the nucleus sacci vasculosi, with many processes containing dense-core vesicles. This group of neurons, located dorsal to the nucleus sacci vasculosi and showing (a) immunoreactivity to neuropeptides or to monoamine-synthesizing enzyme, and (b) cytoplasm with dense-core vesicles, was considered not to be a part of the nucleus sacci vasculosi but rather part of the nucleus tuberculi posterioris. These results support the non-peptidergic and non-aminergic character of the nucleus sacci vasculosi.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00328023
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  • 81
    Digitale Medien
    Digitale Medien
    The metathoracic wing-hinge chordotonal organ of an atympanate moth, Actias luna (Lepidoptera, Saturniidae): a light- and electron-microscopic study (1992)
    Springer
    Cell & tissue research 267 (1992), S. 455-471 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Chordotonal organ ; Scolopidium ; Homology ; Electron microscopy ; Sensilla ; Evolution ; Actias luna (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The structure of a simple chordotonal organ, the presumed homologue of the noctuoid moth tympanal organ, is described in the atympanate moth, Actias luna. The organ consists of a proximal scolopidial region and a distal strand, which attaches peripherally to the membranous cuticle ventral to the hindwing alula. The strand is composed of elongate, microtubule-rich cells encased in an extracellular connective tissue sheath. The scolopidial region houses three mononematic, monodynal scolopidia, each comprised of a sensory cell, scolopale cell, and attachment cell. The dendritic apex is octagonally shaped in transverse section, its inner membrane lined by a laminated structure reminiscent of the noctuoid tympanal organ ‘collar’. A 9+0-type cilium emerges from the dendritic apex, passes through both the scolopale lumen and cap, and terminates in an extracellular space distal to the latter. Proximal extensions of the attachment cell and distal prolongations of the scolopale cell surrounding the cap are joined by an elaborate desmosome, with which is associated an extensive electron-dense fibrillar plaque. Within the scolopale cell, this plaque constitutes the scolopale ‘rod’ material. The data are discussed in terms of both the organ's potential function, and its significance as the evolutionary proto-type of the noctuoid moth ear.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319368
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  • 82
    Digitale Medien
    Digitale Medien
    Culture and characterization of dental follicle cells from rat molars (1992)
    Springer
    Cell & tissue research 267 (1992), S. 483-492 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Dental follicle ; Cell culture ; Fibroblasts ; Immunocytochemistry ; Ultrastructure ; Collagen ; Gel-electrophoresis ; Western blotting ; Rat (Sprague-Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Because the dental follicle is necessary for the eruption of teeth of limited eruption, it was the objective of this study to determine if the cells of the follicle could be cultured in vitro. To achieve this, dental follicles and associated enamel organs were dissected from the first and second mandibular molars of 6–7-day-old rats (secretory stage of amelogenesis), and then cultured in a medium that promotes fibroblast growth — the predominant cell type of the dental follicle. The cultured cells grew to confluency and were kept through 3 passages before experimentation. The cultured cells were fibroblastic in shape, elongate with processes, and transmission electron microscopy revealed that they contained an abundant rough endoplasmic reticulum, but did not form desmosomes. Immunofluorescent staining for anti-vimentin showed that all the cells stained and electron-microscopic immunogold labeling indicated that the antibody was associated with intermediate filaments. As revealed by SDS-polyacrylamide gel electrophoresis and Western blotting, the cultured cells synthesized and secreted the extracellular matrix molecules fibronectin and procollagens. Subsequent immunofluorescence staining of permeabilized and non-permeabilized cells confirmed the presence of fibronectin and type I collagen both intra- and extracellularly. Thus, based on all the above characteristics, the cultured cells appeared to be fibroblasts derived from the dental follicle, although a few of the fibroblasts may be derived from undifferentiated mesenchymal cells interposed between the alveolar bone and follicle. Experiments now can be conducted to determine how these cultured cells respond directly to growth factors that alter the rates of tooth eruption.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319370
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  • 83
    Digitale Medien
    Digitale Medien
    Synaptic contacts of tyrosine hydroxylase-immunoreactive elements in the inner plexiform layer of the retina of Bufo marinus (1992)
    Springer
    Cell & tissue research 267 (1992), S. 525-534 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Retina ; Dopaminergic neurons ; Synapses ; Inner plexiform layer ; Immunocytochemistry ; Electron microscopy ; Bufo marinus (Anura)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Tyrosine hydroxylase (TH) immunocytochemistry was utilized to quantify dopaminergic synapses in the inner plexiform layer of the retina of Bufo marinus. Since dopaminergic cells have bistratified dendritic arborisation in the inner plexiform layer, attention was given to the segregation of synapses between the scleral and the vitreal sublaminae. Light-microscopically, a more elaborate dendritic branching was observed in the scleral than in the vitreal sublamina. In contrast, about 55% of synapses occurred in the vitreal one fifth of the inner plexiform layer, 30% in the scleral fifth, and 15% in the intermediate laminae. Input sources and output targets showed only minor quantitative differences between sublaminae 1 and 5. TH-immunoreactive processes were found in presynaptic (62.8%) and postsynaptic (37.2%) positions. Synapses to the stained dendrites derived from bipolar (40.4%) and amacrine (59.6%) cells, whereas outputs from the TH-positive processes were directed to amacrine cells (56.8%) and to small and medium-sized dendrites (35.4%); at least some of these can be considered as ganglion cell dendrites. TH-positive profiles neither formed synapses with each other nor were presynaptic to bipolar cell terminals. Junctional appositions of the immunoreactive profiles were occasionally seen on non-stained amacrine and ganglion cell dendrites in the scleral sublamina of the inner plexiform layer and on optic axons in the optic fibre layer. Although dopaminergic cells are mainly involved in amacrine-amacrine interactions, inputs from bipolar terminals and outputs to ganglion cell dendrites were also substantial, suggestive of a role also in vertical information processing.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319375
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  • 84
    Digitale Medien
    Digitale Medien
    Structural organization of two fast, rhythmically active crustacean muscles (1992)
    Springer
    Cell & tissue research 267 (1992), S. 571-582 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Crustacean muscle ; Ultrastructure ; Dye coupling ; Flagellum ; Scaphognathite ; Fascicles ; Mitochondria ; Carcinus maenas (Crustacea)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The organization of the flagellum abductor muscle and of a scaphognathite levator muscle of the green crab, Carcinus maenas, has been compared quantitatively using light and electron microscopy. These muscles are rhythmically active at relatively high frequencies and for long durations. Fibers of both muscles are interconnected to form fascicles of 50 or more fibers within which there is cytoplasmic continuity. A single muscle is made up of 8–12 fascicles. Individual fibers consist of a peripheral rind of densely packed mitochondria, a thick region of glycogen granules, and myofibrils arranged into scattered central islands. Less than half the volume-density of these muscles is contractile material, the balance being largely mitochondria and glycogen. The fibers within a muscle are structurally similar. They have short sarcomeres (about 2 μm), thin to thick filament ratios of about 3:1, and junctions between the sarcoplasmic reticulum and the transverse tubules at the M line. Sarcoplasmic reticulum occupies about 10% of the myofibrillar volume-density. A well developed sarcoplasmic reticulum appears to underlie the capacities of these two muscles for high frequency contraction; extensive mitochondria and glycogen stores should confer fatigue resistance under both aerobic and anaerobic conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319380
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  • 85
    Digitale Medien
    Digitale Medien
    Cellular differences in the regeneration of murine skeletal muscle: a quantitative histological study in SJL/J and BALB/c mice (1992)
    Springer
    Cell & tissue research 269 (1992), S. 159-166 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Regeneration ; Skeletal muscle ; Injury ; Autoradiography ; Morphometry ; Electron microscopy ; Mouse (SJL/J BALB/c)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Skeletal muscle regeneration in SJL/J and BALB/c mice subjected to identical crush injuries is markedly different: in SJL/J mice myotubes almost completely replace damaged myofibres, whereas BALB/c mice develop fibrotic scar tissue and few myotubes. To determine the cellular changes which contribute to these differential responses to injury, samples of crushed tibialis anterior muscles taken from SJL/J and BALB/c mice between 1 and 10 days after injury were analysed by light and electron microscopy, and by autoradiography. Longitudinal muscle sections revealed about a 2-fold greater total mononuclear cell density in SJL/J than BALB/c mice at 2 to 3 days after injury. Electron micrographs identified a similar proportion of cell types at 3 days after injury. Autoradiographic studies showed that the proportions of replicating mononuclear cells in both strains were similar: therefore greater absolute numbers of cells (including muscle precursors and macrophages) were proliferating in SJL/J muscle. Removal of necrotic muscle debris in SJL/J mice was rapid and extensive, and by 6 to 8 days multinucleated myotubes occupied a large part of the lesion. By contrast, phagocytosis was less effective in BALB/c mice, myotube formation was minimal, and fibrotic tissue conspicuous. These data indicate that the increased mononuclear cell density, more efficient removal of necrotic muscle, together with a greater capacity for myotube formation in SJL/J mice, contribute to the more successful muscle regeneration seen after injury.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00384736
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  • 86
    Digitale Medien
    Digitale Medien
    Differential localization of leu-enkephalin and hyperglycemic hormone in axon terminals of the sinus gland of the crabsCarcinus maenas, eriocheir sinensis, andUca pugilator (1992)
    Springer
    Cell & tissue research 270 (1992), S. 521-526 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Enkephalins ; Neuropeptides ; Neurohemal organ ; Immunogold ; Electron microscopy ; Carcinus maenas, Uca pugilator, Eriocheir sinensis (Crustacea)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Leu-enkephalin containing secretory granules were demonstrated in axon terminals of immunogoldlabeled electron-microscopic sections of the sinus gland of three brachyuran crustaceans. These granules have a diameter of 120+-15 nm and differ in electron density from those located in adjacent terminals containing hyperglycemic or molt-inhibiting hormone. These neurohormones do not show co-localization with leu-enkephalin. The cross-reactivity of leu-enkephalin antiserum with met-enkephalin is less than 1%. The sinus glands of the three species examined show no immunoreactivity for FMRF-amide. A modulatory activity of endogenous enkephalin by paracrine mechanisms is suggested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00645054
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  • 87
    Digitale Medien
    Digitale Medien
    Immuno-electron-microscopic localization of basic fibroblast growth factor in the dystrophic mdx mouse masseter muscle (1992)
    Springer
    Cell & tissue research 270 (1992), S. 569-576 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Basic fibroblast growth factor ; Regeneration ; Degeneration ; Immunohistochemistry ; Electron microscopy ; Masseter muscle ; Myoneural junction ; Mouse (dystrophic mdx)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The localization of basic fibroblast growth factor (bFGF)-like immunoreactivity in the masseter muscle of dystrophic mdx mice on postnatal day 28 was investigated by immunoblot analysis and electron microscopy. Crude homogenate of the masseter muscle, when subjected to immunoblotting with a bFGF antiserum, exhibited a main band with the same molecular weight (18 kDa) as bovine bFGF. By electron microscopy, bFGF immunoreactivity was detected in small regenerating myocytes; the smaller cells were the premature myocytes, the most intense staining was the immunoreactivity within the cytoplasm. Putative precursors of the muscle cells with a few myofilaments, which were most intensely labeled with anti-bFGF, contacted each other and possibly developed into multinucleated myocytes through cell fusion. Mature myocytes with densely packed myofilaments and peripherally located nuclei did not exhibit bFGF immunoreactivity; they formed myoneural junctions with motor nerve endings immunoreactive for bFGF. Early differentiating myocytes with intense bFGF-like immunoreactivity did not make contact with immunoreactive nerve terminals. Degenerating large myocytes with a limited number of distorted and/or disrupted myofilaments exhibited electron-dense deposits in the cristae of mitochondria; these deposits were not abolished by immunoadsorption control experiments. Thus, the cell-size-dependent decrease in bFGF immunoreactivity in regenerating but not in degenerating myocytes provides a morphological basis for an autoregulatory role of bFGF in muscle regeneration. This study suggests that neuronal bFGF is not involved in initial muscle regeneration in the dystrophic mdx mouse.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00645060
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  • 88
    Digitale Medien
    Digitale Medien
    Ovarian innervation develops before initiation of folliculogenesis in the rat (1992)
    Springer
    Cell & tissue research 270 (1992), S. 87-93 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Ovarian nerves ; Development ; Folliculogenesis ; Tyrosine hydroxylase ; Immunohistochemistry ; Electron microscopy ; Rat (Sprague Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Sympathetic neurotransmitters have been shown to be present in the ovary of the rat during early postnatal development and to affect steroidogenesis before the ovary becomes responsive to gonadotropins, and before the first primordial follicles are formed. This study was undertaken to determine if development of the ovarian innervation is an event that antedates the initiation of folliculogenesis in the rat, Rattus norvegicus. Serial sections of postnatal ovaries revealed a negligible frequency of follicles 24 h after birth (about 1 primordial follicle per ovary). Twelve hours later there were about 500 follicles per ovary, a number that more than doubled to about 1300 during the subsequent 12 h, indicating that an explosive period of follicular differentiation occurs between the end of postnatal days 1 and 2. Electron microscopy demonstrated that before birth the ovaries are already innervated by fibers containing clear and dense-core vesicles. Immunohistochemistry performed on either fetal (day 19) or newborn (less than 15h after birth) ovaries showed the presence of catecholaminergic nerves, identified by their content of immunoreactive tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine biosynthesis. While some of these fibers innervate blood vessels, others are associated with primordial ovarian cells, thereby suggesting their participation in non-vascular functions. Since prefollicular ovaries are insensitive to gonadotropins, the results suggest that the developing ovary becomes subjected to direct neurogenic influences before it acquires responsiveness to gonadotropins.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00381883
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  • 89
    Digitale Medien
    Digitale Medien
    The effects of ageing on the morphology and function of the zonae fasciculata and reticularis of the rat adrenal cortex (1992)
    Springer
    Cell & tissue research 270 (1992), S. 265-272 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Adrenal cortex ; Ageing ; Steroidogenesis ; Electron microscopy ; Morphometry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The morphological counterpart of the well-known age-dependent marked impairment of glucocorticoid secretion of rat adrenals was investigated by use of morphometric techniques. For this purpose 4-, 8-, 16- and 24-month-old rats were studied. Despite the notable lowering of both basal and ACTH-stimulated production of corticosterone by collagenase-dispersed inner adrenocortical cells, ACTH and corticosterone plasma concentrations displayed significant increases with ageing. Zona fasciculata (ZF) and zona reticularis (ZR) showed a notable hypertrophy in aged rats, which was due to rises in both the average volume and number of their parenchymal cells. The hypertrophy of ZF and ZR cells was in turn associated with increase in the volume of the mitochondrial compartment and proliferation of smooth endoplasmic reticulum, i.e., the two organelles involved in steroid-hormone synthesis. All these morphologic changes, conceivably due to the chronic exposure to high levels of circulating ACTH, are interpreted as a response enabling ZF and ZR to compensate for their age-dependent lowering in glucocorticoid secretion. Stereology also demonstrated that ZF and ZR cells underwent a striking age-related lipid-droplet repletion. Lipid droplets are the intracellular stores of cholesterol esters, the obligate precursors of steroid hormones in rats. This finding is in keeping with the contention that the mechanism underlying the age-dependent decline in rat-adrenal glucocorticoid secretion mainly involves impairments of the utilization of intracellular cholesterol previous to its intramitochondrial transformation to pregnenolone.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00328012
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  • 90
    Digitale Medien
    Digitale Medien
    Characterization of macrophage-like cells in the external layers of human small and large intestine (1992)
    Springer
    Cell & tissue research 270 (1992), S. 273-279 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Macrophages ; Small intestine ; Large intestine ; External muscle layer ; Immunohistochemistry ; Histochemistry ; Electron microscopy ; Man
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In the external layers of human small and large intestine macrophage-like cells were characterized by immunohistochemical, histochemical and electronmicroscopical methods. Using immunohistochemistry and a number of monoclonal antibodies, the presence and distribution of phenotypic subpopulations of macrophages were evaluated. In all locations macrophage-like cells were identified with antibody EBM11, which recognizes CD68 antigen, C3bi which recognizes CD11b, and partly with an antibody which recognizes protein 150,95 (CD11c). Macrophage-like cells in the external muscle layer were HLA-DR-positive (expressing the MHC class-II antigen), in contrast to macrophage-like cells in the subserosa and submucosa. Macrophage-like cells in the external muscle layer were mostly acid phosphatase-negative, and at the electron-microscopic level they were found to have features of macrophages: primary lysosomes, coated vesicles and pits. However, very few secondary lysosomes were present. Birbeck granules were not observed. It is concluded that in the external muscle layer of human small and large intestine numerous macrophages of a special type are present. It is discussed whether this cell type plays a role in gastrointestinal motility and/or has an immunological function.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00328013
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  • 91
    Digitale Medien
    Digitale Medien
    Bethanechol and a G-protein activator, NaF/AlCl3, induce secretory response in Paneth cells of mouse intestine (1992)
    Springer
    Cell & tissue research 269 (1992), S. 213-220 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Paneth cells ; Ultrastructure ; Morphometry ; Bethanechol ; Fluoride ion ; G-protein ; Mouse (Balb/c)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Paneth cells located at the bottom of intestinal crypts may play a role in controlling the bacterial milieu of the intestine. Using morphometry to clarify the secretory mechanism of the Paneth cells, we studied the ultrastructural changes in mouse Paneth cells produced following intra-arterial perfusion with Hanks' balanced salt solution containing a cholinergic muscarinic secretagogue (bethanechol), a neuroblocking agent (tetrodotoxin), or a G-protein activator (NAF/AlCl3). Bethanechol (2×10-4 mol/l) induced Paneth-cell secretion. Many Paneth cells massively exocytosed their secretory material into the crypt lumen; the enhanced secretion caused degranulation and vacuole formation. However, tetrodotoxin (2×10-6 mol/l) did not prevent the bethanechol-enhanced secretion by the Paneth cells. NaF (1×10-2 mol/l) and AlCl3 (1×10-5 mol/l) induced massive exocytosis of the Paneth cells; the exocytotic figures were similar to those observed in mice stimulated by bethanechol. G-protein activation was followed by a sequence of intracellular events, resulting in exocytosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319611
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  • 92
    Digitale Medien
    Digitale Medien
    Ultrastructural changes in primordial germ cells during early gonadal development of the common carp (Cyprinus carpio L., teleostei) (1992)
    Springer
    Cell & tissue research 267 (1992), S. 337-346 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Primordial germ cell ; Ultrastructure ; Gonadal differentiation ; Cyprinus carpio (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A description is given of primordial germ cell (PGC) differentiation and gonadal development in carp from hatching until the age of 6 weeks. This period was chosen as the PGCs are mitotically silent before they start to proliferate rapidly after week 6. The PGCs increased in size between week 2 and week 4 after fertilization. Ultrastructurally, the perinuclear dense bodies present in PGCs from hatching onwards increased in size and formed the ‘cement’ between mitochondria. Moreover, from week 2 onwards, an elaborate Golgiapparatus was present in PGCs, indicating synthetic activity that may be related to PGC enlargement. During the observation period, gonadal tissue was gradually formed around the PGCs. From the age of 4 and 5 weeks onwards, two somatic cell types could be distinguished; the central type had a light appearance and was closely associated with the PGCs, the other type being darker and forming the peripheral layer of the developing gonads. Thus, during the period of mitotic quiescence, the PGCs and the gonads actively differentiate in preparation for the fast PGC proliferation that occurs after 6 weeks.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00302972
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  • 93
    Digitale Medien
    Digitale Medien
    Initial formation of cellular intrinsic fiber cementum in developing human teeth (1992)
    Springer
    Cell & tissue research 267 (1992), S. 321-335 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Teeth ; Cementum ; Cementoblasts ; Matrix production ; Electron microscopy ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The present study describes the formative process of the initiation of cellular intrinsic fiber cementum (CIFC) in still growing human teeth. From 29 premolars and molars with incomplete roots developed to 60–90% of their final length, 8 premolars (with roots formed to three quarters of their final length) were selected for electron-microscopic investigation. All teeth were clinically intact and prefixed in Karnovsky's fixative immediately after extraction. Most of them were decalcified in ethylene diaminetetraacetic acid (EDTA), and the apical part of the roots was divided axially into mesial and distal portions that were subdivided in about 5 slices each. Following osmication and embedding in Epon, these blocks were cut for light- and electron-microscopic examination. In addition, 5 teeth with incomplete roots were freed from organic material and processed for scanning electron microscopy. It was found that CIFC-initiation commenced very close to the advancing root edge and resulted in a rapid cementum thickening. Thereafter, appositional growth continued on the already established cementum surface. Large, basophilic and rough endoplasmic reticulum-rich cementoblasts, some of which became cementocytes, were responsible for both fast and slow CIFC-formation. The CIFC-matrix was free of Sharpey's fibers and composed of more or less organized intrinsic collagen fibrils, in part fibril bundles, that ran roughly parallel to the root surface. Initially, the cementum fibrils intermingled with those of the dentinal collagen fibrils, which were not yet mineralized. This boundary subsequently underwent calcification. The development of collagen fibril bundles and their extracellular arrangement were associated with cytoplasmic processes probably involved in fibril formation and fibril assembly. Many cementoblasts contained intracytoplasmic, membrane-bounded collagen fibrils, which probably were related to fibril formation rather than degradation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00302971
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  • 94
    Digitale Medien
    Digitale Medien
    Ultrastructural study of the retinal pigment epithelium during metamorphosis in the sea lamprey (Petromyzon marinus L.) (1992)
    Springer
    Cell & tissue research 267 (1992), S. 375-384 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Retinal pigment epithelium ; Ultrastructure ; Organelle differentiation ; Metamorphosis ; Lamprey, Petromyzon marinus (Cyclostomata)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The sequence of morphological changes in the retinal pigment epithelium during the metamorphic period of the sea lamprey Petromyzon marinus L. has been investigated using electron microscopy. At early metamorphic stages (stages I and II), photoreceptors are present in a small zone of the retina. During these stages, the lateral surface of the epithelial cells shows zonulae occludentes and adhaerentes. The degree of cell differentiation varies throughout the retinal pigment epithelium. Cells covering the differentiated photoreceptors in the central retina have phagosomes, whereas pigment granules appear only in the retinal pigment epithelium dorsal to the optic nerve head. Most epithelial cells have myeloid bodies; their morphology is more complex around the optic nerve head. At stage III, when photoreceptors develop over the whole retina, the distribution of cytoplasmic organelles is almost homogeneous in the retinal pigment epithelium. Subsequently, the basal plasma membrane of the epithelial cells becomes progressively folded and their apical processes enlarged. In addition, extensive gap junctions develop between retinal pigment cells. In late metamorphic stages, noticeable growth of myeloid bodies occurs and consequently the retinal pigment epithelium resembles that of the adult. This study also describes, for the first time, the presence of wandering phagocytes in the retinal pigment epithelium of lampreys; their role in melanosome degradation is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00302976
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  • 95
    Digitale Medien
    Digitale Medien
    Development of cytoplasmic digitations between Leydig cells and testicular macrophages of the rat (1992)
    Springer
    Cell & tissue research 267 (1992), S. 385-389 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Leydig cells ; Macrophages ; Development, ontogenic ; Electron microscopy ; Testis ; (Rat Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Testicular macrophages and Leydig cells from adult animals are known to be functionally coupled. For example, secreted products from macrophages stimulate testosterone secretion by Leydig cells. In adult rat testes, structural coupling also exists between these cells. This coupling consists of cytoplasmic projections from Leydig cells located within cytoplasmic invaginations of macrophages. Although macrophages are known to exist in the testis in immature animals, it is not known when these digitations develop. The purpose of the present study was to determine whether the time of their development coincides with known maturational events that occur in Leydig cells, particularly during the peripubertal period. Testes from rats at 20, 30 and 40-days-of-age as well as testes from mature rats weighing more than 500 gm were prepared for ultrastructural analysis. It was found that digitations form between 20 and 30-days-of-age. These structures varied from simple tubular projections to complicated branched structures, suggesting that digitations are more than simple invaginations of microvilli into coated vesicles as previously described. Subplasmalemmal linear densities were also observed within macrophages juxtaposed to Leydig cells. Collagen was commonly observed between macrophages and Leydig cells in animals 20 days old. These studies demonstrate that although macrophages are present in the testis in maximal numbers at 20 days-of-age, they do not form junctions with Leydig cells until day 30. This is just prior to the major increase in secretory activity of rat Leydig cells that occurs during puberty.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00302977
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  • 96
    Digitale Medien
    Digitale Medien
    In-vitro effects of angiotensin II on steroid production by hamster ovarian follicles and on ultrastructure of the theca interna (1992)
    Springer
    Cell & tissue research 268 (1992), S. 191-196 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Angiotensin II ; Ovarian follicles ; Theca interna ; Ultrastructure ; Steroidogenesis ; Atresia ; Golden hamster (Rodentia)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Angiotensin II (AII) is present in the mammalian ovary and has been correlated with atresia in follicles. Since the theca interna may be one site at which atresia is intiated, we wished to determine whether AII exerts an effect on theca interna from explanted ovarian follicles of hamsters. Hamsters were sacrified on the morning of proestrus, and ovaries were removed. Preovulatory follicles were excised from the ovaries, and cultured with one of the following components: medium alone (control); medium plus AII (1x10-6 M); the AII-receptor antagonist [Sar1, Ile8] AII (1x10-4 M); or AII plus antagonist. After 72 h, the follicles were processed for transmission electron microscopy (to determine quantities of theca interna organelles involved in the steroid synthetic pathway) or for protein determination (to normalize steroid production rates). The incubation medium was drawn off and analyzed by radioimmunoassay for progesterone, androstenedione, or estradiol-17β. There was a significant positive correlation (r=0.92, P〈0.01) between follicular androstenedione secretion and area comprising theca interna smooth endoplasmic reticulum. In the theca interna, AII induced a two-fold and 1.6-fold increase in lipid droplet number and area comprising smooth endoplasmic reticulum, respectively (P〈0.05). Excess antagonist negated the increase in cell or-ganelles and also reduced androstenedione secretion compared with AII alone (P〈0.05). Most importantly, AII significantly augmented the ratio of androstenedione: estradiol-17β secretion by 44% over that of control. The ultrastructural changes observed in this study and the increase in the andostenedione: estradiol-17β production ratio are consistent with atresia-like changes in ovarian follicles. We believe, therefore, that AII is involved, possibly at its membrane receptor, in an aspect of the overall process of follicular atresia, operating in part at the level of the theca interna.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00338068
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  • 97
    Digitale Medien
    Digitale Medien
    Interstitial cells associated with the deep muscular plexus of the guinea-pig small intestine, with special reference to the interstitial cells of Cajal (1992)
    Springer
    Cell & tissue research 268 (1992), S. 205-216 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Intestine ; Interstitial cells ; Pacemaker ; Electron microscopy ; Guinea-pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Interstitial cells associated with the deep muscular plexus of the guinea-pig small intestine were studied by electron microscopy, and three-dimensional cell models were reconstructed from serial ultrathin sections with a computer graphic system. Three types of cells were recognized. The first type was similar in shape to smooth muscle cells, but did not contain an organized contractile apparatus. Many large gap junctions comprising about 4% of the cell surface were present; they connected cells of the first type to each other, to the second type of cell and to smooth muscle cells of the outer circular layer. The second type of cell had a welldemarcated cell body with long slender processes and was characterized by a large amount of glycogen comprising about 9% of the cell volume. The third type of cell was similar to fibroblasts, and contained well-developed Golgi apparatus and rough endoplasmic retiulum. Some of these fibroblast-like cells (a possible subtype) formed small gap junctions. All three types of cells showed close relationships with nerve varicosities. This cellular network consisting of gap-junction-rich cells, glycogen-rich cells and smooth muscle cells may be involved in the pacemaking activity of intestinal movement.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318788
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  • 98
    Digitale Medien
    Digitale Medien
    Ultrastructure of the basement membrane and its precursor in developing rat submandibular gland as shown by alcian blue staining (1992)
    Springer
    Cell & tissue research 268 (1992), S. 233-238 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Alcian blue ; Basement membrane ; Lamina densa ; Meshwork ; Submandibular gland ; Ultrastructure ; Rat (Wistar-Imamichi)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the epithelial basement membrane and membrane precursor was studied in rat submandibular rudiment and a model system of the reconstructed basement membrane, by transmission electron microscopy following alcian blue staining. Directly beneath the epithelial plasma membrane, a meshwork layer was found to consist of anastomosing thin fibers arranged as a three-dimensional meshwork (100–400 nm in thickness). Straight strands (5–10 nm in diameter) could sometimes be seen to pass through the meshwork. Adjacent to this layer, a coarse network composed of threads (20–40 nm in diameter) connected the meshwork layer with collagen fibers of the underlying connective tissue. The earliest precursors recognized in the reconstruction-model system were part of the fine-meshwork structure, and showed this structure to be a fundamental component of the basement membrane.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318791
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  • 99
    Digitale Medien
    Digitale Medien
    12-O-tetradecanoylphorbol-13-acetate induces selective desquamation of superficial cells in rat urinary bladder epithelium (1992)
    Springer
    Cell & tissue research 268 (1992), S. 239-245 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Urinary bladder ; Epithelial desquamation ; TPA ; Electron microscopy ; Rat (Donryu)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary 12-O-tetradecanoylphorbol-13-acetate (TPA) is known to affect the proliferation and/or differentiation of several types of cells. We injected TPA directly into the lumen of rat bladder to determine, using scanning and transmission electron microscopy, its effects on the bladder epithelium in vivo. At 1 h after TPA injection (1μg/ml), the superficial cells of the epithelium had changed their morphology, and large spherical vacuoles occupied their cytoplasm. In some areas, the underlying intermediate cells were exposed by the desquamation of the superficial cells. During the next few hours, TPA was excreted from the bladder lumen by voluntary micturition, but the desquamation of the superficial cells proceeded further. All the superficial cells were lost from the luminal surface by 24 h after TPA injection. The changes noted were specific for the superficial cells and were not observed in the intermediate or basal cells. After 24h, part of the epithelium had a three-layer structure, indicating that regeneration was taking place. These results demonstrate that TPA selectively affects and desquamates superficial cells in a short period of time. This experimental system may be useful for studying in vivo cell proliferation and/or differentiation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318792
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  • 100
    Digitale Medien
    Digitale Medien
    Immunogold labelling of the cytoplasmic estradiol receptor in resting porcine endometrium (1992)
    Springer
    Cell & tissue research 270 (1992), S. 1-6 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Estradiol receptor ; Endometrium ; Ovariectomy ; Immunohistochemistry ; Ultrastructure ; Pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Serial sections of resting porcine endometrium were analyzed with the monoclonal antibody 13H2 using goat antimouse IgG/5 nm gold as secondary reagent or with either polyclonal antibodies from goat #402 or the rat monoclonal antibody H222, both in combination with protein G/12 nm gold. A modestly higher labelling of nuclei than of cytoplasm was seen only with the monoclonal antibody H222. Polyclonal #402 and monoclonal 13H2 showed fewer attachments over nuclear than over cytoplasmic areas. The highest densities of attachment and of predominantly cytoplasmic labelling were obtained with the monoclonal antibody 13H2. The results confirm the earlier assumption of a restricted accessiblity of estradiol receptor in the cytoplasm of resting cells for immunoreagents.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00381873
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