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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 82 (1991), S. 516-519 
    ISSN: 1432-0533
    Keywords: Multidrug resistance ; P-glycoprotein ; Glial tumor ; Immunohistochemistry ; RNA analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The most consistantly reported alteration of multidrug-resistant carcinoma cells is the overexpression of a membrane glycoprotein, termed P-glycoprotein. In this study we examined whether the strong intrinsic chemotherapy resistance of glial tumors might be related to the expression of the MDR1 gene which codes for P-glycoprotein. Fourteen glial tumors were examined immunohistochemically using the monoclonal antibody C219. In addition, RNA samples of 11 of these tumors were analysed using a sensitive Northern blot assay. P-glycoprotein is expressed in all 14 glial tumors; the number of stained tumor cells, however, varied considerably ranging from 0.3% to 15%. There was no correlation between the number of MDR1-positive cells and the histological malignancy. Varying amounts of MDR1 mRNA were detectable in 7 from 11 examined tumors. The results of our study show that the MDR1 gene is expressed in human glial tumors and suggest that the multidrug transporter may contribute to the clinical non-responsiveness of these tumors to chemotherapy.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 81 (1991), S. 641-648 
    ISSN: 1432-0533
    Keywords: Multidrug resistance ; Glial tumors ; Transforming growth factor type β ; Bone morphogenetic protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The multidrug transporting cell membrane molecule P-glycoprotein can be spontaneously expressed in human glioma cells. Transcripts of mdr genes were detected in glial tumor cells by polymerase chain reaction and Northern blotting, expression of P-glycoprotein was analyzed by immunocytochemistry and functional activity by cytofluorometry of fluorescent probe transport. In vitro treatment of glioma cells with vincristine induced coordinate over-expression of both mdr1 and mdr3 genes associated with very high P-glycoprotein-mediated multidrug transport, resistant to the inhibitory activity of chemosensitizers like verapamil. The physiological modulators of multidrug transport are as yet unknown. We therefore initiated a screening program to analyze the effects of cytokines on multidrug transport. We observed, that transforming growth factors β1, -β2, and β1.2-but not the related bone morphogenetic protein (BMP) 2-inhibited multidrug transport. Interestingly, BMP 2 antagonized the TGF-β induced inhibition of multidrug transport.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0533
    Keywords: Key words Heme oxygenase-1 ; Heat shock protein-32 ; Traumatic brain injury ; Cerebral infarction ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Extracellular heme derived from hemoglobin following hemorrhage or released from dying cells induces the expression of heme oxygenase-1 (HO-1, HSP-32) which metabolizes heme to the gaseous mediator carbon monoxide (CO), iron (Fe) and biliverdin. Biliverdin and its product bilirubin are powerful antioxidants. Thus, expression of HO-1 is considered to be a protective mechanism against oxidative stress and has been described in microglia, astrocytes and neurons following distinct experimental models of pathological alterations to the brain such as subarachnoidal hemorrhage, ischemia and traumatic brain injury (TBI) and in human neurodegenerative diseases. We have now analyzed the expression of HO-1 in human brains following TBI (n = 28; survival times: few minutes up to 6 months) and focal cerebral infarctions (FCI; n = 17; survival time: 〈 1 day up to months) by ¶immunohistochemistry. Follwing TBI, accumulation of ¶HO-1+ microglia/macrophages at the hemorrhagic lesion was detected as early as 6 h post trauma and was still pronounced after 6 months. In contrast, after FCI HO-1+ microglia/macrophages accumulated within focal hemorrhages only and were absent in non-hemorrhagic regions. Further, HO-1 was weakly expressed in astrocytes in the perifocal penumbra. In contrast to experimental data derived from rat focal ischemia, these results indicate a prolonged HO-1 expression in humans after brain injury.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0533
    Keywords: Key words Cell culture ; Cell line ; Glioma ; Calcium-binding proteins ; Microglia enzymology ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Allograft inflammatory factor-1 (AIF-1) is a Ca2+-binding peptide that constitutes a potential modulator of macrophage activation and function during the immune response of the brain. Peptides termed microglia response factor-1 or ionized calcium-binding adaptor molecule-1 have been reported to be identical with AIF-1. We have investigated the expression of AIF-1 in the rat C6 glioblastoma and 9L gliosarcoma tumor models and additionally assessed AIF-1 expression in a diverse range of human astrocytomas by immunohistochemistry. AIF-1 was expressed by activated microglial cells and a subset of infiltrating macrophages in areas of infiltrative tumor growth and in compact tumor areas in both rat and human gliomas. Double-labeling experiments in rats and humans characterized the nature and the functional status of AIF-1+ cells. AIF-1 expression was detected in cells expressing major histocompatibility complex class II molecules and in a subset of activated macrophages/microglial cells. All MRP-8+ cells coexpressed AIF-1. In humans, there was a strong correlation of AIF-1-expressing activated macrophages/microglial cells with tumor malignancy (P 〈 0.0001). These results suggest that AIF-1 defines a distinct subset of tumor-associated activated macrophages/ microglial cells.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1437-1596
    Keywords: Key words Ganglion cells ; Hippocampus ; Immunohistochemistry ; Mean optical density (MOD) ; Morphine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Notes: Abstract To investigate the topography of morphine distribution in the human brain, a method has been developed to detect morphine immunohistochemically. In this study hippocampus tissue from victims of heroin overdose (blood morphine concentrations 220 ng/g–1500 ng/g; 6-MAM positive urine sample), known for its high concentration of μ-opiate receptors was used. The immunohistochemical staining was performed with an anti-morphine antiserum originally developed for radio-immuno-assays. In comparison with control specimens from cases of sudden death without morphine exposition or a history of heroin abuse, the brains from victims of heroin overdose showed selectively stained ganglion cells, axons and dendrites, suggesting a massive concentration of morphine in the neuronal structures.
    Type of Medium: Electronic Resource
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