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  • 1
    ISSN: 1432-0533
    Keywords: Glioblastomas ; Organ culture method ; Autoradiography ; Kinetics ; Growth fraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Five human glioblastomas maintained in an organ culture system were studied by autoradiography to determine, after 8 days in vitro, the growth fraction (GF) of the explants, their total cell cycle time (T C) and cell cycle phase durations (T S,T G1,T G2 andT M), and their potential doubling time (T pot) after pulse-labeling with [3H] TdR for 1 h. These parameters were derived from computer analysis of fraction of labeled mitoses (FLM) curves. The results fell into two groups. In two tumors, the cultures had a GF of 0.25 and 0.23. From the FLM curves were derived aT C of 89 and 83 h, aT S of 16.5 and 9.5 h, and aT G1 of 60 and 61 h.T M was estimated at 0.9 and 0.6 h, andT G2 12h. TheT pot was 12 days. These values approximate those reported for glioblastomas and other human malignancies in vivo. The explants of three other glioblastomas gave different FLM curves: the derivedT S were increased to 36 and 55 h, estimatedT M ranged from 2.4 to 4.5 h, andT G2 ranged from 11 to 20 h.T C andT G1 could not be estimated. In two tumors the GF was reduced to 0.12 and 0.11, with aT pot of respectively 52 and 39 days. These values are comparable to those reported for astrocytomas of intermediate malignancy. In the third tumor, the GF was only 0.014. The reduction in GF and the lengthening of cell cycle components in this group of explants are similar to the kinetic changes reported in some in vivo tumors and three-dimensional in vitro systems that have reached a plateau stage of growth. They are probably related to the greater opportunities for cell-to-cell contacts and the resulting increased differentiation favored by the organ culture technique.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0533
    Keywords: Neural cell surface antigens ; Neural differentiation ; Mouse teratoma ; Radioimmune assay ; Immunoperoxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A rabbit antiserum against mouse neonatal brain cell surface membranes labeled by immunoperoxidase (PAP) the cells of the central and peripheral nervous systems of adult and neonatal mice and their processes, as well as the differentiating neuroepithelial cells of three OTT-6050 mouse teratoma-derived tumors. Indirect immunofluorescence on living 14-day-old monolayer cultures of neonatal mouse brain demonstrated reaction of the immune serum with external surface membrane antigens of neuroblasts and of primitive and mature glial cells. Radioimmune assays (RIA) showed almost complete loss of antiserum binding to neonatal mouse brain plasma membranes after absorption with adult or neonatal mouse brain membranes, and no loss of binding after absorption by liver, spleen, kidney, and heart membranes. Cross-reactivity of the immune serum to several non-neural cell types was demonstrated by immunoperoxidase on sperm and sperm-precursors, on moderate numbers of epithelial cells in the medulla of adult mouse thymus, and, in the neonate, on a range of mesenchymal cells. This cross-reactivity was reflected in the RIA by a moderate reduction of immune serum binding to neonatal mouse brain plasma membranes after absorption with testis pellets and with thymus membranes. PAP staining showed loss of crossreactivity after testis or thymus absorption, without climination of neural cell recognition. Absorption with adult or neonatal mouse brain eliminated cross-reactivity. In the teratoma-derived tumors, absorption of the antiserum with testis or thymus eliminated or markedly reduced the PAP staining of primitive neuroepithelial cells, and only moderately reduced, but did not remove, that of neural cells in the mature neuropil. Among the proteins of neonatal mouse brain plasma membranes separated by polyacrylamide gel electrophoresis, there were six distinct bands indicating major proteins ranging from 26,000–54,000 daltons. Autoradiography of the antigen-antibody complexes with125I protein A on the same gels demonstrated three discrete bands of activity at 10,000–12,000, 76,000, and 97,000 daltons, and one greater than 130,000 daltons, suggesting that the immune serum recognizes only minor protein components of the mouse brain plasma membranes. The application of the PAP method to the recognition of neural cell surface antigens considerably enhances the potential of this antiserum as a tool for the early identification of primitive neural cells in the experimental mouse teratoma.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1435-1463
    Keywords: Autoradiography ; neurotensin ; schizophrenia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neurotensin, an endogenous peptide and putative neurotransmitter, exhibits a wide range of interactions with dopaminergic neurons and displays some actions akin to neuroleptics. Moreover, neurotensin receptors are abundant in specific layers of the entorhinal cortex where cytoarchitectural abnormalites have been reported in schizophrenia. We therefore examined the entorhinal cortex from postmortem specimens of five control patients and six schizophrenic patients for alterations in neurotensin receptor quantitation and distribution using receptor autoradiography. Specific125I-neurotensin binding was concentrated in layer II cell clusters, with a 40% reduction in binding in the schizophrenic group (p〈0.05). Moderate binding was observed in both cohorts in deep layers V/VI, with negligible binding in the hippocampus. There was no statistical difference in quantitative neurotensin binding in other lamina of the entorhinal cortex of schizophrenics compared with controls. The characteristic laminar pattern of binding did not differ between cohorts. The reduction in neurotensin binding in schizophrenics is consistent with an increasing number of reports of structural abnormalities in the medial temporal lobe of schizophrenics in general and the entorhinal cortex in particular. Further studies are required to examine the evidence for neuroanatomic and neurochemical pathology in the entorhinal cortex.
    Type of Medium: Electronic Resource
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