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  • Experimental tumor induction  (2)
  • Ultracytochemistry  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 77 (1989), S. 244-253 
    ISSN: 1432-0533
    Keywords: Adenovirus type 12 ; Experimental tumor induction ; Embryonal neuroectodermal origin ; Peripheral neuro-and medulloepitheliomas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Human adenovirus type 12 (Ad 12) was inoculated intraperitoneally, intrapleurally, intramuscularly or subcutaneously into newborn rodents. Tumors developed preferentially in the peritoneal cavities in 93.9% of the hamsters and 82.6% of the mice, but none in rats; in contrast to the high incidence of brain tumors in rats when the virus is injected intracranially. Serial section of peritoneal tissues and muscle of hamsters revealed multicentric microtumors with a close relation to peripheral nerve fibers 10 to 35 days after virus inoculation. Histologically, most tumors consisted of closely packed, irregularly arranged, small spindle or tadpole-shaped cells. However, divergent morphological differentiation showing palisade arrangement of spongioblastic tumor cells forming trabeculae, pseudorosettes with or without central blood vessel, and true rosettes of immature ependymal (ependymoblastic) or medulloepithelial type were observed. No further differentiation was detected on immunohistochemical or electron microscopical examination of the tumor cells. The immature neuroepithelial phenotypes and the early stages of tumor development indicated that Ad 12 had a definite affinity for embryonic neuroepithelial elements that have migrated along the peripheral nerve fibers of newborn hamsters and mice, perhaps with cells of neural crest origin, and had induced primitive neuroectodermal tumors as observed in human peripheral neuroepithelioma and medulloepithelioma.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 78 (1989), S. 232-244 
    ISSN: 1432-0533
    Keywords: Adenovirus type 12 ; Experimental tumor induction ; Central nervous tumors ; Embryonal neuroectodermal origin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intracranial inoculation with human adenovirus type 12 (Ad12) induced tumors multicentrically in the brain and spinal cord of 37.2% of hamsters, 30.2% of mice, and in the brains of 91.0% of rats. Brain tumors developed preferentially at the olfactory bulb, lateral ventricular horns, tapetum region, and ventral and dorso-caudal aspects of the fourth ventricle. In the spinal cord, tumor developed on the dorsal aspect and, in hamsters, at the root of the cauda equina. Microtumors were found almost invariably in the subependymal areas and occasionally in the leptomeninges. The histological and ultrastructural features indicated extremely undifferentiated neoplasms analogous with the intraperitoneal tumors described in the companion report. Closely packed small polygonal or tadpole-shaped tumor cells resembled the subependymal cell remnants of normal perinatal brains. Divergent differentiation consisted in an intermingling of a fascicular or palisading arrangement of spongioblastic cells, of incomplete perivascular pseudorosettes and of neuroblastic (Homer Wright type) rosettes. Neither distinct neuronal nor neurogial fibrils were demonstrated. True ependymoblastomatous and medulloepitheliomatous rosettes were rarely encountered. These results indicate that Ad12-induced tumors in the central nervous system are of embryonal neuroectodermal origin and with limited differentiation, leading to divergent phenotypes corresponding to medulloblastoma, neuroblastoma, primitive spongioblastoma, ependymoblastoma and, rarely, medulloepithelioma.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 34 (1979), S. 395-400 
    ISSN: 1432-1106
    Keywords: Neostriatum ; ChAc ; Ultracytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structural localization of ChAc activity was studied in the rat neostriatum by a ultracytochemical method. The reaction products of ChAc activity were seen in the cisternal structures and plasma membrane of some medium-sized neurons. Some boutons with ChAc-positive vesicles were observed to make an axo-dendritic or axo-somatic symmetrical synapse.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0878
    Keywords: Ca++-ATPase ; K+-NPPase ; Na+-K+ATPase ; Ultracytochemistry ; Photoreceptor cells, retinal ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ca++-ATPase activity was demonstrated histochemically at light- and electron-microscopic levels in inner and outer segments of retinal photoreceptor cells of the guinea pig with the use of a newly developed one-step lead-citrate method (Ando et al. 1981). The localization of ouabain-sensitive, K+-dependent p-nitrophenylphosphatase (K+-NPPase) activity, which represents the second dephosphorylative step of the Na+-K+-ATPase system, was studied by use of the one-step method newly adapted for ultracytochemistry (Mayahara et al. 1980). In retinal photoreceptor cells fixed for 15 min in 2% paraformaldehyde the electron-dense Ca++-ATPase reaction product accumulated significantly on the inner membranes of the mitochondria but not on the plasmalemma or other cytoplasmic elements of the inner segments. The membranes of the outer segments remained unstained except the membrane arrays in close apposition to the retinal pigment epithelium. The cytochemical reaction was Ca++- and substrate-dependent and showed sensitivity to oligomycin. When Mg++-ions were used instead of Ca++-ions, a distinct reaction was also found on mitochondrial inner membranes. In contrast to the localization of the Ca++ -ATPase activity, the K+-NPPase activity was demonstrated only on the plasmalemma of the inner segments, but not on the mitochondria, other cytoplasmic elements or the outer segment membranes. This reaction was almost completely abolished by ouabain or by elimination of K+ from the incubation medium.
    Type of Medium: Electronic Resource
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