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  • Astrocytoma  (1)
  • Peroxidase-vesicular transport  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Neurosurgical review 4 (1981), S. 17-31 
    ISSN: 1437-2320
    Keywords: Astrocytoma ; Oligodendroglioma ; Ultrastructure ; Astrocytom ; Oligodendrogliom ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 7 Oligodendrogliome, davon 2 mit uniformem Zell-Typ, 4 mit Zell- oder Gewebs-Unregelmäßigkeit, 1 mit glioblastomatösen Veränderungen wurden elektronenmikroskopisch untersucht. Die Tumorzellen zeigten 2 Haupttypen mit morphologischen Übergängen zwischen beiden auf. Die Hauptformen wurden als Typ 1 (undifferenziert) und 2 (differenziert) definiert, gestützt auf die Anzahl anaplastischer Zellen im jeweiligen Tumor und auf die Beobachtung nicht-neoplastischer Oligodendrocyten nach Mori and Leblond (21). Die meisten Tumorzellen aller Fälle wiesen ähnliche licht- und elektronenmikroskopische Charakteristika auf, einschließlich der Zell-Anordnung und ihrer Tendenz, zytoplasmatische Fortätze zu bilden. Diese Befunde waren auch in den glioblastomähnlichen Tumoren zu erkennen und bestätigen damit deren Oligodendrogliom-Komponente. Außerdem fand man regelmäßig in allen Tumoren eine Zunahme der Größe und Zahl der Mitochondrien, reichlich intrazytoplasmatische Strukturen und Mikrotubuli. Auch Zellen mit zytoplasmatischen Filamenten waren vorhanden, die als reaktive Astrocyten oder als oligodendrogliale Tumorzellen angesehen wurden. Daher scheinen weder zytoplasmatische Filamente noch Mikrotubuli ein spezifisches morphologisches Kriterium für Oligodendroglia oder Astrocyten zu sein. Das Überwiegen einer dieser beiden Strukturen erlaubt jedoch eine zytogenetische Zuordnung. Die zytologischen Charakteristika sind zwar keine spezifischen morphologischen Kriterien; die Feststellung ihrer Anwesenheit gibt jedoch wichtige diagnostische Informationen.
    Notes: Summary Seven Oligodendrogliomas (2 with uniform cell type, 4 with cellular or tissue variability, and 1 with glioblastomatous changes) were examined ultrastructurally. The tumor cells were of two principal types with morphologic transitions between the two main types. The two principal cell types were identified as type 1 (undifferentiated) and type 2 (differentiated) on the basis of the number of anaplastic cells in an individual tumor and on the observations of Mori and Leblond (21) on non-neoplastic oligodendrocytes. Most of the tumor cells in all tumors exhibited similar histologic and ultrastructural characteristics including their arrangement and their tendency to form cytoplasmic processes which sometimes formed short stacks. These features were also recognizable in the glioblastomatous example and confirmed the presence of an oligodendroglial component. In addition to these characteristics, an increase in size and number of mitochondria, abundant intracytoplasmic structures, microtubules were regularly present in virtually all tumor cells. Cells rich in cytoplasmic filaments were present. These were identified as reactive astrocytes or as oligodendroglial tumor cells. Thus neither cytoplasmic filaments nor microtubules appear to be specific morphological markers for oligodendroglia or astrocytes; only the predominance of one of these structures permits cytogenetic identifications. The cytologic characteristics are not specific morphologic markers; however, recognition of their presence provides important diagnostic information.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 40 (1977), S. 207-212 
    ISSN: 1432-0533
    Keywords: Ultraviolet ; Irradiation ; Edemahorseradish ; Peroxidase-vesicular transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Focal vasogenic brain edema was induced by ultraviolet irradiation of the exposed cerebral cortex of 16 cats. In 5 animals horseradish peroxidase was intravenously injected at times varying from 30 min to 24 h following irradiation and allowed to circulate for 45 min. Fixation was carried out by perfusion and immersion with glutaraldehyde. The tissue, part of it incubated for peroxidatic activity, was treated for electron microscopy. The UV-irradiation leads to a shallow coagulation of the superficial cortex from which a wide zone of edematous tissue spreads to the deep white matter within 24 h. Arterioles, capillaries and venules of this zone show enhanced pinocytotic activity and a con-current rise in permeability for horseradish peroxidase which is found in micro- and macropinocytotic vesicles, in tubular vesicle-like structures, in endothelial wall invaginations and apparently not membrane-bound. These changes are most pronounced in venules which after 48 h allow penetration of reaction product though the base membrane into the surrounding neuropil. There is no evidence for the penetration of tight junctions which appear intact.
    Type of Medium: Electronic Resource
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