Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The fine structure, histometric characteristics, and permeability of microvessels were studied by electron microscopy in normal and in ethylnitrosourea (ENU)-induced glioma tissue from rats, using horseradish peroxidase (HRP) as a tracer. The tumor vessels were classified into (1) capillary buds (Type I); (2) round small to large capillaries (Type II); (3) sinusoidal or venule-like microvessels (Type III), and (4) abnormal arteriole-like microvessels (Type IV). All endothelial cells, basement membranes and periendothelial cells in the tumor tissue demonstrated changes in structure. The most striking alterations occurred in the endothelial cells; there were abnormal endothelial tight junctions, altered pinocytotic activity, and thickening. In the tracer study, the reaction product of HRP was present around some sinusoidal or venule-like microvessels (Type III) and extended to the widened extracellular spaces around the microvessels. The endothelial cells of Type III microvessels showed decreased nuclear and mitochondrial fractions, and increased euchromatin content and a rough endoplasmic reticulum fraction. The pinocytotic vesicles with the HRP reaction product in the endothelial cells were not increased in number. Fenestrations and gaps of the endothelial cells were observed. These alterations of the endothelial cells of sinusoidal or venule-like microvessels (Type III) are considered to be the main cause of breakdown of the blood-brain barrier in this tumor.
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PMID:Microvascular abnormalities in ethylnitrosourea (ENU)-induced rat brain tumors: structural basis for altered blood-brain barrier function. 683 65

A detailed analysis of mammalian cell surface proteins is described by a new two-dimensional polyacrylamide gel electrophoresis technique. The first dimension gel contains 2% acrylamide, 0.1% sodium dodecyl sulfate, 0.3% Triton CF10 and 9 M urea. A combination of the detergents and urea permits the separation of poorly soluble, hydrophobic cell surface proteins. Under these conditions, the molecular size of proteins has a limited contribution to the fianl separation due to a low acrylamide concentration. Differences in charge properties, hydrophobicity, and glycosylation are the elements determining the resolution. In the second dimension, the proteins are separated primarily according to molecular weights, by a conventional polyacrylamide gel system in the presence of 0.1% sodium dodecyl sulfate. In this study, proteins of C6 rat glioma cell line are characterized. Cell surface proteins are specifically radio-labeled with 125I by a lactoperoxidase method, and compared with presumptive integral surface proteins which are resistant to extraction with 0.1 M NaOH. Also studied are total cellular proteins, fucose- and glucosamine-containing glycoproteins, and protein species with variable susceptibility to weak trypsin digestion. The electrophoresis system allows an unambiguous identification of each protein species.
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PMID:A two-dimensional polyacrylamide gel electrophoresis system for the analysis of mammalian cell surface proteins. 700 22

Experimental brain tumours were produced in cats by stereotactic implantation of 4 million suspended cells of a rat glioma clone into the internal capsule. Three weeks after implantation a spherical tumour developed with a diameter of up to 10 mm which was surrounded by vasogenic white matter oedema. In untreated animals water content in the peritumoural white matter increased form 69.1 +/- 0.9 to 80.0 +/0 0.8 ml/100 g w. w., and regional blood flow reciprocally decreased from 32.2 +/- 5.6 to 18.9 +/- 0.05 ml/100 g/min. A single injection of a crystalline suspension of 10 mg/kg dexamethasone given intramuscularly one week before the animals were killed, led to a significant amelioration of brain oedema. Peritumoural white matter water content decreased to 73.0 +/- 0.5 ml/100 g w w. and blood flow rose to 35.7 +/- 2.8 ml/100 g/min. These changes were accompanied by parallel shifts of electrolyte content buy did not correlate with EEG activity, as assessed by Fourier frequency analysis. Corticosteroids did not prevent extravasation of peroxidase or Evans blue across the tumour vessels. The beneficial effect, therefore, is attributed to either an acceleration of resorption or an inhibition of the spread of oedema from tumour into the peritumoural brain tissue.
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PMID:Corticosteroid therapy of experimental tumour oedema. 732 60

Two normal and seven malignant human glia lines grown in vitro wer labelled by lactoperoxidase catalysed iodination. The labelled cell surface glycoproteins were isolated by lectin affinity chromatography and compared by SDS gel electrophoresis. The glia and the glioma lines possess a common characteristic glycoprotein pattern. Seven glycoproteins in the molecular weight range between 70,000 and 220,000 daltons and several minor components of low molecular weight could be distinguished. The expression of the glycoproteins was independent of the passage number or the growth conditions although the expression of the different glycoproteins showed quantitative differences for the individual cell lines. The differences found in the tumor lines were either due to an amplification or decrease in the expression of the different glycoproteins and/or their accessibility to the lactoperoxidase-catalysed labelling.
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PMID:Surface glycoproteins of normal and neoplastic glia cells in culture. 739 45

Previous studies have shown that serum proteins are taken up from extracellular oedema fluid by reactive astrocytes and by tumour astrocytes. The present investigation was designed to define the mechanism of this protein uptake. Two or 3-week-old explant cultures from 26 astrocytic gliomas, one anaplastic ependymoma, and five non-glial intracranial tumours were treated with either human IgG (12 mg/ml), human serum albumin, (44 mg/ml) or horseradish peroxidase (0.1--4.0 mg/ml) for 4--24 h. Human IgG and albumin were subsequently detected in cultured cells by the indirect peroxidase-antiperoxidase (PAP) method for light microscopy or by direct peroxidase conjugate technique for electron microscopy. Horseradish peroxidase activity was localised by treatment with diaminobenzidine and hydrogen peroxide. Results of the study show that human serum proteins and horseradish peroxidase are taken up by tumour astrocytes and ependymal cells, and by macrophages, but not by non-glial tumour cells nor by mesenchymal elements in the glioma cultures. Electron immunocytochemistry suggests that the serum proteins are taken up by smooth walled micropinocytic vesicles (approximately 80 nm in diameter) which fuse to form larger endocytic vesicles (200--300 nm); these vacuoles in turn fuse with secondary lysosomes to form cytoplasmic bodies 1.2--3 mum in diameter.
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PMID:Mechanisms of uptake and the fate of serum proteins and horseradish peroxidase in cultured human glioma cells. A light- and electron-immunocytochemical study. 744 81

The sulfhydryl agent, cysteamine (CSH), promotes the accumulation of autofluorescent, peroxidase-positive cytoplasmic granules in cultured astroglia akin to those which naturally accumulate in astrocytes of the aging periventricular brain. Both in vitro and in situ, CSH rapidly induces various heat shock proteins (HSP) in astrocytes long before granulation occurs. In the present study, we determined that CSH treatment resulted in an increase in HSP 27, HSP 90 and heme oxygenase (HO-1) at both the protein and mRNA level. We also showed that C6 glioma cells, unlike primary astrocytes, constitutively express HSP 27, HSP 90 and HO-1 at low levels. Moreover, CSH is incapable of eliciting further HSP expression or inducing granulation in the glioma cells. Our results support the hypothesis that the biogenesis of redox-active astrocytic inclusions in CSH-treated glial cultures and in the aging periventricular brain is dependent on an antecedent cellular stress response.
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PMID:Differential effects of cysteamine on heat shock protein induction and cytoplasmic granulation in astrocytes and glioma cells. 747 27

This study evaluates cerebral entry of mouse interferon alpha/beta (MuIFN alpha/beta) or mouse interferon gamma (MuIFN-gamma) following continuous (3 day), subcutaneous infusion of normal or glioma bearing mice. The intracerebral C57BL/6 mouse glioma-26 (G-26) model was used at days 10-14 post tumor implant, the advanced stage of glioma progression as defined by histology and the median survival time (27 +/- 3.8 days). The infusion of horseradish peroxidase (HRP) in vivo at day 10 or 11 post glioma implant showed strong staining in the tumor bed indicating compromised blood-brain barrier (BBB). In addition, histochemistry with Bandeiraea simplicifolia isolectin B4 demonstrated the accumulation and/or activation of macrophage/microglia. The 3 day infusion of mice (day 11-14 post tumor implant) via subcutaneous (sc) osmotic micro-pumps with MuIFN alpha/beta (8x10(5) - 1.7x10(6) international units [IU]/ml) or with recombinant mouse interferon gamma (rMuIFN-gamma) (1x10(6) IU/ml) resulted in a low but detectable (1-5 IU/ml) cerebral level of IFN. The IFN levels in the blood (20-40 IU/ml) and brain, measured by assay of inhibition of viral cytopathic effect (CPE) or ELISA assay for MuIFN-gamma, showed no difference between normal and glioma bearing mice. The lipoxygenase (LO) activity (dioxygenase) of glioma tissue and contralateral control was evaluated in non-treated and MuIFN alpha/beta continuously (3 day) treated mice. The LO activity in glioma tissue was significantly higher (p < 0.05) than the contralateral control in non-treated mice. However, following sc MuIFN alpha/beta infusion the LO activity of glioma decreased to control level.
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PMID:Interferon entry through the blood-brain barrier in glioma and its effect on lipoxygenase activity. 752 Nov 51

Formalin-fixed, paraffin-embedded surgical specimens from 140 primary human central nervous system tumors, including 51 meningiomas, 26 astrocytomas, 26 anaplastic astrocytomas, 9 glioblastomas, 1 gliosarcoma, 8 oligodendrogliomas, 5 ependymomas, 2 subependymomas, 9 medulloblastomas, and 3 paragangliomas, were immunostained using a streptavidin/peroxidase method and the PC10 monoclonal antibody, which recognizes an epitope on the proliferating cell nuclear antigen (PCNA). The following PCNA labeling index (LI) mean values were found for the above neoplasms: meningiomas, 3.80 +/- 7.35%; astrocytomas, 0.65 +/- 1.03%; anaplastic astrocytomas, 8.46 +/- 7.95%; glioblastomas, 10.26 +/- 11.21; gliosarcoma, 46.34%; oligodendrogliomas, 2.31 +/- 3.59%; ependymomas, 1.12 +/- 2.10%; medulloblastomas, 23.91 +/- 11.95%; and paragangliomas, 2.07 +/- 1.86%. Collectively, our findings indicate that while benign central nervous system tumors generally have low PCNA LI values, consistent over-expression of PCNA epitopes was noted in some examples, especially in a number of meningiomas. Among the malignant neuroectodermal tumors, medulloblastomas were found to have the highest PCNA LI values, corresponding to their histological grade of malignancy, and malignant glial tumors generally displayed significantly higher PCNA LI values, than their benign counterparts. Although in our study mean PCNA LI values seemed to reflect histological grading, large discrepancies were noted in all tumor groups. Our data, therefore, suggest than PCNA immunoreactivity can not be considered reliable for predicting the prognosis of the disease in individual cases.
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PMID:Proliferating cell nuclear antigen immunoreactivity in human central nervous system neoplasms. 768 17

Plectin is a high molecular weight protein originally identified and characterized as a major cytoskeletal component of the C6 rat glioma cell. Here we demonstrate by immunoblotting of crude intermediate filament (IF) protein preparations that plectin is a cytoskeleton-associated component of the rat spinal cord. We then used avidin-biotin peroxidase immunocytochemistry and indirect immunofluorescence to localize plectin within the adult rat central nervous system (CNS) and examine its distribution with respect to IF proteins. Plectin immunoreactivity is localized to all ependymal cells including the choroidal epithelial cells and tanycytes, Bergmann glial processes, radially oriented glial cells in the spinal cord, astrocytes in white matter, a subset of astrocytes in gray matter, a subset of motoneurons in the brainstem and spinal cord, and certain endothelial cells. Colocalization studies with neural IF proteins show that plectin has a unique distribution pattern which most closely resembles, but is distinct from, that of vimentin. The few plectin positive neurons invariably also contain the neurofilament triplet proteins and peripherin, so that the ability of plectin to bind to the triplet proteins in vitro may reflect an in vivo interaction. The predominance of plectin at the inner ventricular boundaries of the nervous system as well as at the blood-brain barrier is in line with the pattern of plectin expression in other tissues and suggests a general role for plectin in the maintenance of such junctional regions.
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PMID:Distribution of plectin, an intermediate filament-associated protein, in the adult rat central nervous system. 802 73

Both horseradish peroxidase (HRP) and Evans blue dye (EBD) have been used previously to characterize the status of the blood-brain barrier (BBB) within brain tissue transplants and host brain tissue. We investigated the possibility that a differential permeability of the vasculature to these two markers can account for discrepancies in the literature concerning the presence of an intact BBB within the grafted tissues. Intravascular injection of both HRP and EBD was used to evaluate the status of the BBB within intracerebral tissue transplants. Simultaneous injection of HRP and EBD in rats with adrenal medulla transplants or C-6 glioma tumors demonstrated a lack of a BBB within these grafts. Both markers produced consistent results within each tissue type, although HRP was generally a more sensitive marker. In contrast to the lack of a BBB in the C-6 gliomas or adrenal medulla transplants, 1-week-old fetal striatal transplants had a BBB essentially intact to both HRP and EBD. Any reported discrepancies in the characterization of the BBB are not likely due to differences between the properties of HRP or EBD. Fetal striatal transplants appear to have an intact BBB at 1 week following transplantation.
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PMID:Permeability of the blood-brain barrier within rat intrastriatal transplants assessed by simultaneous systemic injection of horseradish peroxidase and Evans blue dye. 803 64


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