Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0017636 (glioblastoma)
18,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eighteen patients with Cushing's disease were treated with reserpine and pituitary irradiation. Complete remission was obtained in 9 out of 18 patients after reserpine treatment of 1-2 mg per day for a mean period of 20.4 months, and pituitary irradiation with a mean of 5,865 rads. In another 9 patients, reserpine 0.8-2 mg per day for a mean period of 22.5 months, and pituitary irradiation with a mean of 6,650 rads, were employed. Of these 9 patients, an additional subtotal adrenalectomy was carried out in 6 patients who are now in complete remission. Because of severe psychic symptoms resulted from the original disease in 2 of the remaining 3 patients, subtotal adrenalectomy was performed first and pituitary irradiation and reserpine treatment followed. Remission was eventually obtained in these 2 cases. One patient refused the operation, and thus had little clinical remission. All of the 17 cases in remission were followed up for periods of 6 months to 10 yr. During this time, only one case which had responded to reserpine and pituitary irradiation relapsed, but regained remission following resumption of therapy. Another died of cerebral glioblastoma 4 yr after remission of the disease. It was noteworthy that endocrinologic data including: plasma levels of ACTH and 11-OHCS, suppressibility by dexamethasone, responses of plasma GH to arginine and to insulin loads, and diurnal rhythm of plasma 11-OHCS were nearly normal in a considerable number of the cases in remission. Effectiveness of the combined therapy with reserpine and pituitary irradiation for treating Cushing's disease may support a working hypothesis that reserpine acts through some as yet unknown mechanism to correct a presumed central nervous disorder, while suitable pituitary irradiation probably corrects the pituitary dysfunction directly.
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PMID:Treatment of Cushing's disease with reserpine and pituitary irradiation. 115 59

Integrins are heterodimeric transmembrane proteins with large ectodomains and a short cytoplasmic tail inside the cell. They mediate cell adhesion to extracellular matrix proteins and to the surfaces of other cells. In many cases the sequence recognised by the integrins in the extracellular matrix proteins is the tripeptide Arg-Gly-Asp (RGD). Short synthetic peptides containing this sequence can inhibit invasion in vitro and tumour dissemination in vivo. Thus, the alpha 5 beta 1 fibronectin binding integrin appears to be the key integrin in the invasion of at least melanoma, osteosarcoma and glioblastoma cells. Modulation of the level and activities of this integrin can suppress invasion, whereas the alpha v beta 3 vitronectin binding integrin appears to be associated with increased invasiveness. There is increasing evidence that some of these effects are mediated through signals elicited by the binding of integrins to their target proteins. This possibility has generated a great deal of interest in the cytoplasmic molecules that might mediate the integrin-associated signalling.
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PMID:The Walter Herbert Lecture. Control of cell motility and tumour invasion by extracellular matrix interactions. 150 96

Glioblastoma multiforme, the most malignant astroglial-derived tumor, grows as an adherent mass and locally invades normal brain. An examination of adult cerebral glioblastoma biopsy material for the expression of adhesive proteins that might potentiate adhesion and invasion demonstrated tumor cell-associated vitronectin (5/5). In contrast, vitronectin was not detected associated with glial cells in low grade astroglial tumors (0/4), reactive astrogliosis (0/4), or in normal adult cortex and cerebral white matter (0/5). Also, a wide variety of other adhesive ligands were absent from the glioblastoma tumor parenchyma. The alpha v beta 3 integrin was the only vitronectin receptor identified in glioblastoma tumors in situ, and was also not expressed on low grade astroglial-derived tumors, reactive astrogliosis, or on glia or neurons in normal adult cortex and cerebral white matter. In a cell attachment assay, cultured glioblastoma cells attached to the parenchyma of glioblastoma tumor cryostat sections at the sites of vitronectin expression, but failed to attach to normal brain. This adhesion was inhibited by antibodies directed against vitronectin, the alpha v beta 3 integrin, and with an Arg-Gly-Asp-containing peptide. These data provide evidence for a cell adhesion mechanism in glioblastoma tumors that might potentiate glioblastoma cell invasion of normal brain.
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PMID:Glioblastoma expression of vitronectin and the alpha v beta 3 integrin. Adhesion mechanism for transformed glial cells. 172 25

Transforming growth factor-beta (TGF-beta), a regulator of cell growth and differentiation, is secreted by most cultured cells in latent form (L-TGF-beta). Activation of L-TGF-beta can be achieved by various physico-chemical treatments, including acidification, alkalinization, heating and chaotropic agents. Proposed physiological activators include proteinases and glycosidases, which, however, only lead to limited activation (15-20% of the total TGF-beta activity after acidic activation). In the present study L-TGF-beta 1 partially purified from human platelets was not activated by treatment with neuraminidase or the proteinases plasmin, endoproteinase Arg-C, elastase and chymotrypsin. The mechanism of activation of L-TGF-beta was further assessed by using the human glioblastoma cell line 308, which releases biologically active TGF-beta 2. Factor(s) secreted by 308 glioblastoma cells were found to be able to activate partially purified L-TGF-beta 1 from human platelets. Our finding may prove to constitute a physiologically relevant mechanism for the activation of latent forms of TGF-beta in vivo.
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PMID:Activation of human platelet-derived latent transforming growth factor-beta 1 by human glioblastoma cells. Comparison with proteolytic and glycosidic enzymes. 183 Feb 5

The interaction of cells with extracellular matrix components such as fibronectin, vitronectin, and type I collagen has been shown to be mediated through a family of cell-surface receptors that specifically recognize an arginine-glycine-aspartic acid (RGD) amino acid sequence within each protein. Synthetic peptides containing the RGD sequence can inhibit these receptor-ligand interactions. Here, we use novel RGD-containing synthetic peptides with different inhibition properties to investigate the role of the various RGD receptors in tumor cell invasion. The RGD-containing peptides used include peptides that inhibit the attachment of cells to fibronectin and vitronectin, a peptide that inhibits attachment to fibronectin but not to vitronectin, a cyclic peptide with the opposite specificity, and a peptide, GRGDTP, that inhibits attachment to type I collagen in addition to inhibiting attachment to fibronectin and vitronectin. The penetration of two human melanoma cell lines and a glioblastoma cell line through the human amniotic basement membrane and its underlying stroma was inhibited by all of the RGD-containing peptides except for the one that inhibits only the vitronectin attachment. Various control peptides lacking RGD showed essentially no inhibition. This inhibitory effect on cell invasion was dose-dependent and nontoxic. A hexapeptide, GRGDTP, that inhibits the attachment of cells to type I collagen in addition to inhibiting fibronectin- and vitronectin-mediated attachment was more inhibitory than those RGD peptides that inhibit only fibronectin and vitronectin attachment. Analysis of the location of these cells that were prevented from invading indicated that they attached to the amniotic basement membrane but did not proceed further into the tissue. These results suggest that interactions between RGD-containing extracellular matrix adhesion proteins and cells are necessary for cell invasion through tissues and that fibronectin and type I collagen are important for this process.
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PMID:Inhibition of in vitro tumor cell invasion by Arg-Gly-Asp-containing synthetic peptides. 245 Jan 1

The cyclin kinase inhibitor WAF1/CIP1, also termed CDKN1, mediates p53-induced cell cycle arrest in response to DNA damage. This property makes it an attractive tumour-suppressor candidate for a p53-associated tumour-suppressor gene. In order to investigate the role of WAF1/CIP1 in the pathogenesis of primary human brain tumours we performed single-stranded conformation polymorphism (SSCP) analysis and direct sequencing of exon 2 of the gene in a representative series of 158 brain tumours and corresponding blood samples. In addition, all tumours were examined for mutations in exons 5-8 of the p53 gene. Analysis of WAF1/CIP1 revealed multiple polymorphisms, the most abundant being AGC-->AGA (Ser-->Arg) at codon 31 with an allele frequency of 8.5%. Less common polymorphisms included GTG-->GGG (Val-->Gly) at codon 25, GCC-->ACC (Ala-->Thr) at codon 64, CGC-->CTC (Arg-->Leu) at codon 32, GGC-->AGC (Gly-->Ser) at codon 14 and GCG-->GTG (Ala-->Val) at codon 39 each with an allele frequency of 0.3%. These polymorphisms were all located in a conserved region of exon 2. Two of the polymorphisms were also seen in a group of 157 healthy controls indicating that WAF1/CIP1 polymorphisms do not predispose to cancer. None of the tumours included in our series showed a somatic mutation in WAF1/CIP1. All samples were also analysed for loss of heterozygosity on the short arm of chromosome 6 in the region of the WAF1/CIP1 locus. Allelic loss was observed in only one patient with a glioblastoma. Mutations in the p53 gene were found in 22 of 158 tumours. No association was found between any polymorphism of the WAF1/CIP1 gene, p53 mutations and histopathological tumour type. Our data indicate that WAF1/CIP1 mutations are probably not involved in the formation of primary human brain tumours.
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PMID:Multiple polymorphisms, but no mutations, in the WAF1/CIP1 gene in human brain tumours. 757 73

The cellular content of mutant p53 and hsp72 proteins following gamma-ray irradiation, UV irradiation, and heat treatment was studied in A-7 cells, a human glioblastoma cell line. A-7 was found to contain a mutant p53 gene in which the arginine codon at position 175 was substituted by a histidine codon. Although the p53 gene was mutant, the phenotype of the p53 protein appeared wild-type since the cellular content of the p53 protein was limited under normal culturing conditions. The quantity of mutant p53 and hsp72 proteins in A-7 was increased by heat treatment as well as gamma-ray and UV irradiation. Furthermore, the mutant p53 protein was coimmunoprecipitated with anti-hsp72/hsc73 antibody. Additionally, hsp72 and hsc73 were coimmunoprecipitated with anti-p53 antibody. These results suggest that in A-7, p53 protein accumulation may be caused as a result of response to stressors, such as gamma-ray, UV and heat and that mutant p53 protein and hsp72/hsc73 may manage biological functions cooperatively after gamma-ray, UV and also heat treatments.
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PMID:Accumulation of mutant p53 and hsp72 by heat treatment, and their association in a human glioblastoma cell line. 759 17

Recent studies using a rat model of pneumococcal meningitis have shown that nitric oxide synthase (NOS) inhibitors greatly attenuated microvascular changes and brain edema formation. The site of NO production during bacterial meningitis is unknown. In this study we tested whether primary astrocyte cultures from neonatal rat cortex can be induced to release NO upon stimulation with pneumococci. NO production was assessed by measuring nitrite in the cell culture supernatant using the Griess reaction. Stimulation with heat-killed unencapsulated pneumococci (HKP) increased nitrite concentrations in astrocyte culture supernatants in a dose-dependent fashion. Administration of N-nitro-L-arginine (L-NA), aminoguanidine, L-canavanine, cycloheximide, and dexamethasone prevented the increase in nitrite concentrations. Addition of L-arginine, but not of D-arginine, partially reversed the inhibitory effect of L-NA. Administration of SOD increased nitrite accumulation. Moreover, at 72 h after stimulation with heat-killed pneumococci (10(7) cfu/ml) astrocytes showed an inducible NOS-like immunoreactivity. Accumulation of nitrite was also observed when rat cerebellar neurons and microglia were stimulated with HKP, whereas there was only a slight increase of nitrite in media of rat C6 glioma cells, but no increase of nitrite when the human glioblastoma cell line LN-229 was stimulated with HKP. There was a stronger increase in nitrite levels when astrocytes from Lewis rats were used compared to that from Wistar rats. In conclusion, our study indicates that astrocytes, neurons and microglia are inducible for NO production upon stimulation with pneumococci.
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PMID:Production of nitrite by primary rat astrocytes in response to pneumococci. 764 48

The effects of NG-methyl-L-arginine (L-NMA), an inhibitor of nitric oxide formation, were studied in dogs treated with interleukin-2 (IL-2). The administration of IL-2 to dogs resulted in hypotension within 3 days of treatment. The development of hypotension correlated with accumulation in the serum of nitrate, which is a stable breakdown product of nitric oxide. Administration of L-NMA decreased serum nitrate levels and increased the mean arterial pressure. The antihypotensive effect was dose dependent with a maximum effect observed at a dose of 20 mg/kg. Administration of a continuous infusion of L-NMA (5 mg.kg-1.h-1) maintained the mean arterial pressure for 48 h with concurrent administration of IL-2. Evaluation of IL-2-induced lymphokine-activated killer cell proliferation and tumoricidal activity toward a canine glioblastoma target cell line was unaffected by L-NMA. These studies imply that L-NMA may effectively ameliorate the dose-limiting hypotension associated with administration of IL-2 without adversely affecting the antitumor effects.
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PMID:NG-methyl-L-arginine, an inhibitor of nitric oxide formation, reverses IL-2-mediated hypotension in dogs. 800 55

We used a glioblastoma multiform (GBM) cell line to study the mechanism of cellular regulation of nitric oxide (NO) production. Our experiments indicate a confluent monolayer of GBM cells to release NO as measured through its oxidized NO2 form which gradually accumulates and reaches a peak by 7 to 10 days of culture. the addition of the L-arginine analogs L-NG-monomethyl-L-arginine and L-N omega-nitro-L-arginine and dexamethasone to the GBM cultures caused a substantial inhibition of NO production. The addition of monoclonal antibodies against IL-1 and TNF alpha to the cultures resulted in an inhibition of NO production, whereas the addition of anti-TGF beta monoclonal antibodies resulted in an increase in NO production. These findings suggest the presence of an autocrine regulatory mechanism for NO production in some tumor cell lines.
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PMID:Autocrine regulation of the production of the gaseous messenger nitric oxide in a glioblastoma cell line. 826 90


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