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  • 1
    ISSN: 1432-0533
    Keywords: Medulloblastoma ; Retinal ; Rod-opsin ; S-Antigen ; Photoreceptor cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of the present study was to evaluate the putative photoreceptor differentiation found in certain cerebellar medulloblastomas. The analyses were focussed on S-antigen, rod-opsin (the apoprotein of the visual pigment rhodopsin) and 11-cis retinal (the prosthetic group of rhodopsin). Fresh frozen and paraffinembedded biopsy specimens of three medulloblastomas were investigated by means of immunocytochemistry, enzyme-linked immunosorbent assay (ELISA), high-pressure liquid chromatography (HPLC), and immunoblotting. As shown in paraffin sections, one out of the three tumors (tumor A) contained S-antigen- and rod-opsin-immunoreactive tumor cells. The immunoblotting technique revealed in this tumor a single protein band of approximately 48–50 kDa that reacted with the S-antigen antibody and three protein bands of approximately 40, 75 and 110 kDa recognized by the rod-opsin antibody. These bands could not be detected in the two remaining tumors (tumor B and C). The rod-opsin content of tumor A was quantified by the ELISA; 11.7 pmol rod-opsin were calculated for the biopsy. The HPLC demonstrated the presence of 11-cis- and all-trans-retinal in tumor A, but not in tumors B and C. Furthermore, it was shown that 11-cis-retinal was converted to all-trans-retinal upon illumination of the tumor extract. The ratio between 11-cis-and all-trans-retinal was approximately 1:1 before illumination and 3:5 after illumination. A total of 2–3 pmol of retinal was found in the biopsy of tumor A. In addition all-trans-retinol was present in this tumor. The results indicate that certain medulloblastomas express a functional photopigment and S-antigen, another protein of the phototransduction cascade. They strongly support the concept that medulloblastoma cells may differentiate along the photoreceptor cell lineage.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 80 (1990), S. 448-452 
    ISSN: 1432-0533
    Keywords: Collision tumors ; Metastasis of cancer to cancer ; Glial fibrillary acidic protein ; Cytokeratins ; Brain tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This report presents the case of a 74-year-old woman who was simultaneously affected by two highly malignant neoplasms, a metastasizing renal cell carcinoma and a glioblastoma with sarcomatous component. Leptomeningeal metastasis of renal carcinoma is shown to invade the glioblastoma at its margin. Especially in gliomas, “cancer to cancer” phenomenoma are only rarely documented. Support by immunohistochemical data may prove those events to be more frequent than assumed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 83 (1992), S. 308-314 
    ISSN: 1432-0533
    Keywords: Large T-antigen ; Transgenic mice ; Pineal cell tumors ; Pineal organ ; Primitive neuroectodermal tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Adult transgenic mice expressing the large T-antigen of the Simian virus 40 (SV 40) under the control of the Moloney murine sarcoma virus (MSV) enhancer and the SV 40 promoter develop inheritable uniform midline brain neoplasms showing features of primitive neuroectodermal tumors. The origin and histogenesis of these tumors were investigated in the present study. The brain and pineal organ of fetal and young transgenic mice less than 3 months old displayed normal macroscopic and microscopic features. In 3.5-month-old animals, the pineal organ was considerably enlarged due to hyperplasia, finally leading to tumor formation. Immunocytochemical demonstration of large T-antigen showed that this oncoprotein was already expressed in the nuclei of certain cells in the pineal organ of fetuses (16 and 18 days old) and newborn animals, but was absent from all other parts of the brain. The immunocytochemical demonstration of S-antigen (arrestin), a highly characteristic marker for pinealocytes, was used for further characterization of the large T-antigenimmunoreactive cells. The fetal pineal organ did not contain immunoreactive S-antigen. This first occurred in certain pinealocytes of newborn mice. Double immunostaining revealed that in newborn and older transgenic mice the immunoreactive large T-antigen was exclusively found in nuclei of cells containing S-antigen immunoreaction in their cytoplasm. Thus, transformed pinealocytes appear as stem cells of the experimental tumors. The results of this study suggest that primitive neuroectodermal tumors and the normal tissue from which they originate share certain molecular and immunocytochemical features.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0533
    Keywords: Interphotoreceptor retinoid-binding protein (IRBP) ; Medulloblastoma ; Retinoblastoma ; Pineocytoma (-blastoma)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Previously, immunoreactive rod-opsin and S-antigen (arrestin), two highly characteristic markers of retinal photoreceptors and pinealocytes, were shown to be present in certain medulloblastoma cells. It, thus, has been suggested that such cells differentiate along the photoreceptor lineage. This is corroborated in the present immunocytochemical investigation using antibodies against another photoreceptor-cell marker, the interphotoreceptor retinoid-binding protein (IRBP). As shown in preparations of human retina and pineal organ, IRBP can be successfully demonstrated in formalinfixed and paraffin-embedded tissue: the IRBP immunoreaction is located to the outer and inner segments of retinal photoreceptor cells and to perikarya of certain pinealocytes. Examination of formalin-fixed, paraffinembedded biopsy specimens of 66 cerebellar medulloblastomas revealed varying numbers of IRBP-immunoreactive tumor cells in 19 cases that were formerly shown to contain rod-opsin and S-antigen immunoreaction. IRBP-immunoreactive tumor cells were also found in a retinoblastoma and a pineocytoma, but not in neuroblastoma, ganglioneuroblastoma, glioblastoma, oligodendroglioma and astrocytoma. The results indicate: (1) cerebellar medulloblastomas are heterogeneous in their differentiation potential; (2) one type of medulloblastoma displays photoreceptor characteristics; (3) this type appears to be closely related to retinoblastoma and pineal cell tumors; and (4) all three types of tumors may display additional common features to be explored in future studies.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0533
    Keywords: Key words Oligodendroglioma ; Neurofilament ; Glial fibrillary acidic protein ; Survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have characterized a new polyclonal antibody against heavy chain (H) of neurofilament which can be used to demonstrate neurofilament H in normal brain tissue and oligodendroglioma cells immunocytochemically and immunochemically. Using this antibody we found neurofilament H-immunoreactive tumor cells in 13 oligodendrogliomas (6 WHO grade II, 7 WHO grade III) out of 84 oligodendrogliomas investigated (59 WHO grade II and 25 WHO grade III). Double immunolabeling and confocal laser scanning microscopy showed colocalization of neurofilament H and glial fibrillary acidic protein in certain oligodendroglioma cells. Colocalization of neurofilament and synaptophysin was observed only rarely. The results support the notion that oligodendrogliomas consists of a heterogeneous cell population displaying various stages of differentiation and dedifferentiation. The occurrence of neurofilament H-immunoreactive tumor cells in oligodendrogliomas is not related to the survival of the patients.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Acta neurochirurgica 142 (2000), S. 1071-1072 
    ISSN: 0942-0940
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1459
    Keywords: Lactic acidosis ; Mitochondrial myopathy ; Mitochondrial encephalopathy ; Stroke-like episodes ; Myoclonus epilepsy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Acute episodes of focal neurological dysfunction are a well-recognized complication of the mitochondrial encephalomyopathies. Because of rapid remission, biochemical tests and other diagnostic procedures are mostly performed after the acute phase. We report the case of a patient suffering from mitochondrial disease manifesting primarily with seizures, progressive deafness and dementia, who experienced multiple stroke-like episodes. Other members of the family with evidence of mitochondrial dysfunction are presented briefly. EEG and biochemical findings in the acute stage are correlated with clinical symptoms, showing characteristics distinct from the chronic illness. The possible involvement of dietary factors in the provocation of stroke-like episodes is discussed and regulation of glucose intake suggested as a strategy in the prevention of stroke-like episodes.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neuro-oncology 16 (1993), S. 177-178 
    ISSN: 1573-7373
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1573-7373
    Keywords: Brain tumor ; nitrosoureas ; neurotoxicity ; chemotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-7373
    Keywords: MTT assay ; test variables ; brain tumors ; chemosensitivity test ; cell culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this study was to optimize the experimental conditions of the MTT assay for primary cultures of human brain tumors. This assay is based on the mitochondrial reduction of MTT-(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) salt to formazan crystals by living cells. Formazan can be quantified spectrophotometrically. This assay measures the antimetabolic and, by using an adequate recovery period for the cells, also the antiproliferative effects of cytotoxic drugs. Our results suggest the following experimental design for its application as an chemosensitivity assay for human brain tumors: 1-h drug exposure followed by a seven days recovery period without drugs. Then tumor cells are incubated 4 hours with 1 mg MTT/ml and final absorbance readings are performed at 550 nm and 630 nm as test and reference wavelengths respectively. In this way, the assay seems to be a reliable and simple method for rapid chemosensitivity testing in human brain tumors.
    Type of Medium: Electronic Resource
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