Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0017636 (glioblastoma)
 18,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Postoperative neurological deficit may result from ischaemic or hypoxic hypoxaemia. Postural cerebral hypoperfusion may ensue when a pre-existing asymptomatic vascular anomaly in combination with rotation of the head for surgical positioning compromises cerebral blood flow. CASE REPORT. A 30-year-old man was referred for recraniotomy for glioblastoma. Following uneventful induction of anaesthesia, increased diuresis and progressive hypothermia were observed. The postoperative period was complicated by a seizure, followed by apnoea requiring reintubation of the trachea. A CAT scan revealed global cerebral oedema with subtotal compression of the third ventricle. Intracranial pressure was 60 mm Hg as measured by an epidural probe. On the 1st postoperative day clinical and electroneurophysical signs of brain death were observed; the patient underwent organ explantation the next day. PATHOLOGY. Pathological examination revealed pronounced global hypoxaemic lesions and an S-shaped internal carotid artery with intimal proliferation (Fig. 1). The diagnostic conclusion was cerebral ischaemia following carotid occlusion caused by carotid kinking and completed by surgical positioning (rotation of the head). CONCLUSION. Carotid kinking is a rare abnormality, and patients at risk may not be identified preoperatively. Though it is questionable whether this disaster could have been prevented at all, electroneurophysiological monitoring would have been the only early monitoring system capable of detecting diminishing cerebral blood flow. Although a request for routine intraoperative neurophysiological monitoring seems unrealistic at present, it has to be acknowledged that only such monitoring could have provided the information needed to save this patient.
 ...
PMID:[A fatal intraoperative cerebral ischemia following kinking of the internal carotid artery?]. 163 22

We have been studying the role of human cytomegalovirus (HCMV) as a potential cofactor in human immunodeficiency virus (HIV)-related disease. The clinical relevance of HCMV is highlighted by the fact that it is a principal viral pathogen in patients with AIDS and is known to infect the same cells as HIV. In this study, we focused on the molecular interactions between HIV and HCMV in human fibroblasts and in the human glioblastoma/astrocytoma-derived cell line U373 MG, cells which can be productively infected by both viruses. Because these cells are CD4-, we used HIV pseudotyped with a murine amphotropic retrovirus as described previously (D. H. Spector, E. Wade, D. A. Wright, V. Koval, C. Clark, D. Jaquish, and S. A. Spector, J. Virol. 64:2298-2308, 1990). Initial studies showed that when cells were preinfected with HIV (Ampho-1B) for 5 days and then superinfected with HCMV, HIV antigen production dropped significantly in the coinfected cells but continued to rise in cells infected with HIV (Ampho-1B) alone. HCMV production, however, was unaffected by the presence of HIV. Further analysis showed that HIV steady-state RNA levels and gag and env protein production were also inhibited in the presence of HCMV. The transcriptional inhibition of HIV was particularly surprising in view of the previous results of several other laboratories as well as our own that HCMV infection stimulates HIV long terminal repeat-chloramphenicol acetyltransferase (LTR-CAT) expression in transient expression assays. To investigate this further, we transfected the HIV LTR-CAT construct into either uninfected cells or cells which had been preinfected with HIV. The cells were infected with HCMV 24 h posttransfection and assayed for CAT gene expression at 48 h after HCMV infection. Although there was some stimulation of the LTR-CAT in cells that were dually infected by HIV and HCMV, it was 16-fold less than that in the cells infected only with HCMV. This suggests that in the presence of the HIV infection, the stimulation of the HIV LTR-CAT gene by HCMV is significantly reduced. Experiments with UV-irradiated HCMV and the HCMV DNA polymerase inhibitor ganciclovir showed that HCMV transcription is necessary for the reduction in HIV production to occur; however, replication of the HCMV genome or any events which take place after DNA replication are not necessary. These results, coupled with the observation that inhibition is usually first seen between 8 and 24 h after HCMV infection, suggest that an HCMV early protein is involved in repression of HIV.
 ...
PMID:Human cytomegalovirus inhibits human immunodeficiency virus replication in cells productively infected by both viruses. 165 86

Human monocytes obtained from healthy volunteers and isolated by centrifugal elutriation were not cytotoxic to allogeneic tumorigenic cells. These freshly isolated monocytes were rendered tumoricidal following interaction in vitro for 24 hours with greater than 0.01 micrograms lipopolysaccharide (LPS)/ml or over 1 microgram nor-muramyl dipeptide/ml. Monocytes activated by this procedure produced a soluble factor that lysed tumor cells. Full expression of tumor cell lysis required a minimum of 18 hours' exposure of tumor cells to the factor. The degree of tumor cytotoxic factor (TCF) production was closely related to the intensity of monocyte activation to become tumoricidal. Significant production of TCF by monocytes was detected in the supernatants after treatment for 3 hours with LPS. TCF was also released by activated monocytes when cocultivated with tumorigenic cells. Similarly, the level of TCF production correlated with the monocyte density. TCF destroyed human allogeneic tumor cell lines (melanoma, glioblastoma, colon carcinoma, prostatic carcinoma, and breast carcinoma), but it did not affect nontumorigenic cell lines (lung and skin fibroblasts). TCF activity was not blocked by superoxide dismutase, catalase, or protease inhibitors; it was destroyed by being heated at 100 degrees C for 2 minutes. The ability of activated monocytes to release TCF could enhance host defense against cancer.
 ...
PMID:Kinetics and function of tumor cytotoxic factor(s) produced by human blood monocytes activated to the tumoricidal state. 385 62

Only 43 cases of glioblastoma multiforme of the cerebellum have been reported in the literature. This report is based on the findings of 3 cerebellar glioblastomas in a review of 1,206 consecutive confirmed cases of glioblastoma operated on between 1947 and 1977 at the Istituto Neurologico of Milan, giving an incidence of 0.24%. Clinical features are similar to those of any other fast-growing subtentorial tumour. Neuroradiological studies, including CAT, are of little help in predicting the exact nature of these tumours before surgery. A correct diagnosis can be reached only by microscopic examination. Histological patterns appear in no way to differ from those of cerebral glioblastoma. The biological behaviour of these tumours is in all respects identical to that of glioblastoma of cerebral hemispheres.
 ...
PMID:Glioblastoma multiforme of the cerebellum: description of three cases. 625 46

The c-kit proto-oncogene encodes a tyrosine kinase receptor for stem cell factor and plays a critical role in the growth and differentiation of various types of cells including hematopoietic stem cells. To investigate the mechanisms of its transcriptional regulation, we isolated the 5' flanking region of the human c-kit gene and characterized its promoter activity in hematopoietic cells. Nucleotide sequence analysis revealed that the 1.2 kb 5' flanking region lacked a typical "TATA box," but had a relatively high G + C content and four potential Sp1-binding sites. Putative binding sites for AP-2, basic helix-loop-helix proteins, Ets-domain proteins, Myb and GATA-1 were also found. Primer extension and S1 nuclease protection analyses of hematopoietic cells indicated that the major transcription start sites are 62 bp and 58 bp upstream of the translation start site. Essentially the same start sites were detected in non-hematopoietic cells such as small cell lung carcinoma and glioblastoma: this single promoter in c-kit is different from the multiple promoter system of c-fms, a c-kit-related gene, in which at least two promoters are differently used in hematopoietic and non-hematopoietic cells. An analysis of the c-kit 5' flanking region using the bacterial chloramphenicol acetyltransferase gene (CAT assay) in human erythroleukemia HEL cells, which express the endogenous c-kit mRNA at high levels, showed that a region from -180 to -22 is important for the expression of the c-kit gene. In addition, a negative regulatory element(s) is suggested to be involved in the regulation of the c-kit gene expression in mammals.
 ...
PMID:Characterization of the promoter region of the human c-kit proto-oncogene. 750 48

We have studied the formation of hydroxyl radical (OH.) induced by doxorubicin in a series of doxorubicin- or vincristine-selected variants of C6 rat glioblastoma cells in culture by electron-spin resonance spectroscopy using 5,5'-dimethyl-1-pyrroline-1-oxide as a spin trap. Wild-type cells, sensitive to doxorubicin, exhibited in the presence of this drug a concentration-dependent OH. formation which could be inhibited by preincubation with superoxide dismutase, catalase or an antibody against cytochrome P450-reductase. In highly doxorubicin-resistant cells, OH. formation was reduced to about 20% of the level obtained in sensitive cells. In cells presenting a very low level of resistance to doxorubicin or in cells selected with vincristine, both presenting a pure multidrug-resistant phenotype, OH. formation was identical to that obtained in sensitive cells. In cells of intermediate resistance or in revertant cells, intermediate levels of OH. formation were obtained. Protection against OH. formation and action can be identified at the levels of superoxide dismutase and glutathione peroxidase activities, which are both enhanced in the resistant cells.
 ...
PMID:Doxorubicin-induced oxygen free radical formation in sensitive and doxorubicin-resistant variants of rat glioblastoma cell lines [corrected and republished erratum originally printed in FEBS Lett 1993 May 17;322(3):295-8]. 839 2

The aquaporin-4 (AQP4) gene encodes proteins of approximately 31 and 34 kDa with distinct N-terminal sequences. Both protein isoforms are expressed in brain, whereas mainly the smaller isoform is found in other tissues. We isolated the promoter sequences upstream of exon 0 (encoding the longer isoform) and exon 1 (encoding the shorter isoform). The exon 0 promoter region contained multiple TATA and CCAAT boxes and Sp1, AP1, and E-box elements; the exon 1 promoter lacked a CCAAT box but contained a TATA box and AP1, AP2, and E-box elements. Utilizing the CAT reporter assay, promoter activities were 7- to 9-fold greater for fragments from exon 1 vs exon 0 in human glioblastoma cells (SF-126, U-87 MG) and 11- to 13-fold greater in kidney cells (MDCK and LLC-PK1). Promoter deletion analysis indicated a strong suppressor element located just upstream of nucleotide -428 in the exon 0 promoter. RT-PCR analysis of human brain and kidney cDNAs confirmed much higher relative expression of transcript containing exon 0 vs exon 1 in brain. These results indicate differential transcriptional regulation of two AQP4 isoforms and suggest that tissue-specific factors regulate their relative expression.
 ...
PMID:Isolation and functional analysis of alternative promoters in the human aquaporin-4 water channel gene. 967 32

We investigated the effect of the peroxisomal proliferator (PP) perfluorodecanoic acid (PFDA), alone or in combination with 9-cis-retinoic acid (RX) on the human glioblastoma cell line Lipari (LI). Cell proliferation, apoptotic rate, peroxisome morphology and morphometry, peroxisomal enzyme activities and the presence of peroxisome proliferator-activated receptors (PPARs) were examined. We show that PFDA alone produces pleiotropic effects on LI cells and that RX enhances some of these effects. Peroxisomal number and relative volume, as well as palmitoyl-CoA oxidase activity and protein, are increased by PFDA treatment, with a synergistic effect by RX. The latter, alone or in association with PFDA, induces catalase activity and protein, increases apoptosis and decreases cell proliferation. PPAR isotypes alpha and gamma were detected in LI cells. While the former is apparently unaffected by either treatment, the latter increases in response to PFDA, independent of the presence of RX. The results of this study are discussed in terms of PPARalpha activation and PPARgamma induction by PFDA, by either a direct or an indirect mechanism.
 ...
PMID:Presence and inducibility of peroxisomes in a human glioblastoma cell line. 1077 93

The aim of this study was to evaluate the role of bcl-2 in 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) sensitivity of the ADFS human glioblastoma cell line in vitro and in vivo. To this end, the ADFS line expressing a low level of the bcl-2 protein was transfected with a bcl-2 expression vector. We found that bcl-2 overexpressing clones were less sensitive to in vitro BCNU treatment than the control clone. Cell cycle analysis demonstrated that while BCNU induced a consistent block in S/G2-M phases of the cell cycle in the control clone, it did not affect the cell cycle phase distribution of the two bcl-2 transfectants. The different sensitivity to BCNU was unrelated to the ability of bcl-2 to inhibit apoptosis, while bcl-2 appeared to protect bcl-2 transfectants from BCNU toxicity through an increase of catalase activity. The ability of the catalase inhibitor, sodium azide, to increase the BCNU sensitivity of the bcl-2 transfectants to levels of the BCNU-treated control clone substantiated the role of the catalase activity. The effect of bcl-2 in reducing sensitivity to BCNU was also confirmed by in vivo experiments. Xenografts of bcl-2 overexpressing tumors were less sensitive to BCNU treatment than xenografts originating from control cells.
 ...
PMID:Bcl-2 overexpression decreases BCNU sensitivity of a human glioblastoma line through enhancement of catalase activity. 1159 15

Glioblastoma is one of the most radioresistant tumors. Exposure of cells to ionizing radiation leads to formation of reactive oxygen species (ROS) that are associated with radiation-induced cytotoxicity. ROS scavengers, therefore, are one of the important factors in protecting cells against ROS injury during ionizing radiation exposure. In the present study, we isolated and established a radioresistant variant clone (RRC) from U251 human glioblastoma cell line and investigated the potential role of antioxidant enzymes in radioresistance of the glioblastoma cell line. RRC showed a higher radioresistance than the parent cell line as measured by clonogenic survival assay and showed delayed G2/M arrest. Antioxidant enzymes, such as superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX), glutathione reductase (GR), were activated up to 5-fold in RRC compared to the parent cells after radiation. In addition, RRC also had cross-resistance to the antitumor agent cisplatin. Therefore, radioresistance and cross-resistance to chemotherapeutic agent in RRC might be due to the highly coordinated activation of antioxidant enzymes rather than a single enzyme alone.
 ...
PMID:Increased expression of antioxidant enzymes in radioresistant variant from U251 human glioblastoma cell line. 1513 30


1 2 3 4 Next >>