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)

Microspectrofluorometry was used to study the regulation of intracellular pH (pHi) in 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF)-loaded astrocytes and the neuroblastoma-glioma cells of the NG 108-15 line. The cells rapidly regulated pHi during an acid transient induced by an NH4+ prepulse. This regulation was blocked by removal of Na+, or by addition of 1 mM amiloride. The back regulation was also inhibited when extracellular pH (pHc) was lowered. Furthermore, when cells were exposed to buffer with reduced or increased pHc, pHi changed in parallel. Thus, although these cells possess at least one efficient H+ extrusion mechanism, which is likely to be the ubiquitous Na+/H+ antiporter, they fail to regulate pHi to a normal value unless pHc is held constant. The implications of these findings are discussed.
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PMID:The regulation of intracellular pH in cultured astrocytes and neuroblastoma cells, and its dependence on extracellular pH in a HCO3-free solution. 129 78

We have used cytofluorometry to examine the formaldehyde sensitivity of the binding of a monoclonal antibody (MAB) to its epitope on glial fibrillary acidic protein in human malignant glioma cells in culture. When acetone-extracted whole cells or cytoskeletons, made by extracting with Triton in stabilizing buffer (Tsb), are fixed with formaldehyde, binding of the MAB Tp-GFAP1 to GFAP is abolished or greatly reduced. Fixation with the bifunctional protein crosslinking reagent dithiobis (succinimidyl propionate) (DTSP) has the same negative effect as formaldehyde. If cytoskeletons are further extracted with Tsb containing 250 mM ammonium sulfate (Thsb), fixation with formaldehyde or DTSP has reduced or no effect on the binding of Tp-GFAP1. The data are consistent with the hypothesis that aldehyde sensitivity of Tp-GFAP1 is caused by the crosslinking of a second protein to GFAP that blocks the binding of the MAB to its epitope. This putative blocking protein is part of the Triton-insoluble cytoskeleton, but it begins to be solubilized in 50 mM ammonium sulfate and it is largely removed in 250 mM ammonium sulfate (Thsb). SDS-PAGE shows that extraction with Thsb also removes a large number of proteins from the cytoskeleton, one of which could be the blocking protein. A second antibody to GFAP, designated Tp-GFAP3, was raised against cytoskeletons which had been fixed with DTSP and in which the epitope recognized by Tp-GFAP1 was presumably blocked. Tp-GFAP3 is not sensitive to fixation by either formaldehyde or DTSP.
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PMID:Formaldehyde sensitivity of a GFAP epitope, removed by extraction of the cytoskeleton with high salt. 244 10

A protein has been isolated from bovine brains by using a modification of the procedure used to purify glia maturation factor. The method consists of ammonium sulfate precipitation, chromatography with DEAE-Sephacel, Sephadex G-75, and hydroxylapatite columns, passage through a heparin-Sepharose column, and finally fractionation by reverse-phase HPLC with a C4 column. The isolated protein reacts strongly with the mouse monoclonal antibody G2-09 and has a molecular weight of approximately 17,000 and an isoelectric point of pH 4.9. The N terminus is blocked, but tryptic digestion releases 28 peptides, 8 of which have been sequenced. The total known residues add up to more than two-thirds of the entire 140-residue protein, estimated from amino acid composition, and show no sequence homology with any known protein. Reversible thermal renaturation greatly enhances its biological activity. The purified protein stimulates differentiation of normal neurons as well as glial cells. It inhibits the proliferation of the N-18 neuroblastoma line and the C6 glioma line while promoting their phenotypic expression. We designate this protein glia maturation factor beta.
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PMID:Purification and characterization of glia maturation factor beta: a growth regulator for neurons and glia. 272 56

Rubrophilin, a unique brain specific polypeptide, was purified to apparent homogeneity from microsomal fractions of bovine brains. The peptide stains pink with Coomassie Brilliant Blue R-250 (C.I. No. 42660) under specific conditions, has an apparent Mr of 53,000, and is acidic with an apparent pI of 4.9. The purification involves initial solubilization of delipidated microsomes in sodium dodecyl sulfate, followed by ammonium sulfate fractionation, reversed ammonium sulfate gradient elution from diatomaceous earth, gel filtration on polyacrylamide (Biogel P-200), gradient elution chromatography from hydroxylapatite, and reverse-phase chromatography from phenyl-Sepharose. A yield of about 5 mg of rubrophilin was obtained from 9 g of microsomal proteins. Amino acid analysis shows that rubrophilin contains only nine amino acids with residues/mol as follows: alanine (102), glutamic acid (97), lysine (65), proline (55), aspartic acid (48), glycine (44), serine (37), threonine (35), and valine (10). Cysteine, methionine, tryptophan, tyrosine, isoleucine, phenylalanine, histidine, and arginine could not be detected. Relative rubrophilin content of vertebrate brains was as follows: mammals greater than birds greater than reptiles greater than fishes. It is present in mouse retina and human neuroblastoma cell cultures but could not be detected in octopus optic lobe or in cultured C-6 rat glioma cells.
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PMID:Purification and properties of rubrophilin: a novel brain specific membrane polypeptide. 380 7

Previous work from this laboratory described an association, based on genetic evidence, between a 68 000 dalton protein (p68) and corticotropin (ACTH) sensitive adenylate cyclase activity among variants of the Y1 mouse adrenocortical tumor cell line. To study the nature of this association further, we have purified p68 and raised a polyclonal anti-p68 serum in rabbits. A variant subclone of the Y1 line, in which p68 comprised approximately 10% of total soluble protein, was used as starting material. Purification of p68 was achieved by passage of a 100 000 X g supernatant fraction over DEAE-cellulose, fractionation with ammonium sulfate, and chromatography on hydroxylapatite. The purified protein had an isoelectric point of 7.3, a polarity value of 46%, and a blocked amino terminal end group. A rabbit antiserum raised against the purified p68 had a titer of 1:16 000 and specifically precipitated p68 from extracts of Y1 cells labeled with L-[35S]methionine. Using this antiserum, p68 also was detected in other cell lines including mouse erythroleukemia and Sertoli cells; rat Leydig, ovary, and glioma cells; and Chinese hamster ovary cells. The presence of p68 in a variety of cell types suggests that the function of p68 is not restricted to adrenal cells or to specific actions of ACTH.
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PMID:A 68 000 dalton protein genetically associated with corticotropin-sensitive adenylate cyclase activity. Purification and preliminary characterization using a specific antiserum. 608 78

A macromolecule has been partially purified which influences the choice of the neurotransmitter synthesized by sympathetic neurons. Previous studies showed that culture medium conditioned by incubation on certain types of non-neuronal cells increased [3H]acetylcholine synthesis and accumulation from [3H]choline in primary cultures of neurons dissociated from neonatal rat superior cervical ganglion and grown in the virtual absence of non-neuronal cells. A concomitant decrease of [3H]catecholamines production was observed (Patterson, P. H., and Chun, L. L. Y. (1977) Dev. Biol. 56, 263-280). The active cholinergic factor in conditioned medium from C6 glioma or primary rat heart cultures has been purified about 1500-fold by a sequence of ammonium sulfate precipitation, DEAE-, CM-cellulose, and Sephadex G-100 chromatography. The partially purified factor is active at 1 microgram of protein/ml of culture medium and is eluted from Sephadex columns as a single peak of apparent Mr = 40,000-45,000. This material is insensitive to 0.2 M 2-mercaptoethanol, but is inactivated by 1 mM Na periodate. Its activity is partially decreased by treatment with a protease from Streptomyces griseus but is unaffected by neuraminidase. Material purified through the ammonium sulfate, DEAE- and CM-cellulose steps contains large amounts of trypsin- and chymotrypsin-inhibiting activities.
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PMID:A diffusible factor responsible for the determination of cholinergic functions in cultured sympathetic neurons. Partial purification and characterization. 611 Jun 68

We examined the effect of tetanus toxin on clonal neuroblastoma X glioma hybrid cells, NG108-15, by intracellular microelectrode studies of passive membrane electrical properties and action potentials generated under various conditions. Binding of tetanus toxin to the surface of the cells was demonstrated by indirect immunofluorescent staining but no morphological alteration was observed in tetanus toxin-treated cells under a phase contrast microscope. These is no significant difference between the tetanus toxin-treated and untreated cells in their passive electrical membrane properties, i.e. resting membrane potentials, input resistances, time constants and input capacities. Cells in 120 mM Na+, 2 mM Ca2+ salt solution showed Na spikes, and cells in high Ca2+ (30 mM), Na+-free salt solution showed Ca spikes in response to depolarizing current pulses. While the Na spike was not affected by tetanus toxin, the Ca spike was blocked by the toxin. The minimum dose of tetanus toxin for maximum suppression of the peak potential level of the Ca spike was 250 ng/ml. Addition of tetraethyl ammonium (TEA) to extracellular fluid enhanced the Ca spike in untreated cells. In toxin-treated cells, TEA did not alter the effect of tetanus toxin on the Ca spike. Blockade of the Ca spike by tetanus toxin could be detected even at low extracellular Ca2+ concentration (10 mM) by adding TEA to the extracellular fluid and adjusting the membrane potential to a steady hyperpolarized level (-80 mV) to ensure optimal and uniform electrical responses. The usefulness of NG108-15 hybrid cells for in vitro investigations on the mechanism of action of tetanus toxin was discussed.
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PMID:Action of tetanus toxin on cholinergic neuroblastoma X glioma hybrid cells: selective blockade of Ca spikes. 637 74

The immunoregulatory effects of TCGF (T-cell growth factor) on the generation and growth of syngeneic murine malignant glioma (20-methylcholanthrene-induced 203-glioma)-specific killer T-cell were investigated in C57BL/6 adult mice in order to clarify the immunopotential usefulness for anti-tumor local adoptive immunotherapy against malignant brain tumor. TCGF was prepared and assayed. Briefly, 5 x 10(6) ml mouse spleen cells were cultured with 2 microgram/ml concanavalin A in RPMI-1640 medium supplemented with 2% fetal calf serum for 24 hours. Culture supernatants were concentrated by ammonium sulphate precipitation (55 to 80% saturation) and purified by gel filtration (Sephadex G-100, a molecular weight from 30 to 36,000 daltons) and ion exchange chromatography (DEAE-cellulose, elution with 0.15 M in NaCl at ph 7.4). The purified TCGF had no IFN activity. Assays for TCGF was performed for quantitative analysis using 203-glioma-specific killer T cell clone (G-CTLL), which was obtained by limiting dilution method (0.3 cells/well in 96 well microtiter plate) and maintained for over 6 months in the presence of TCGF. Titer (U/ml) of TCGF was defined as the quantity of TCGF required to obtain one-half of the maximal stimulation of G-CTLL proliferation assay. It was confirmed that the specific killer T-cell against 203-glioma was generated in mice after intracranial as well as subcutaneous inoculation of the tumor cells. The killer T-cell activity of spleen cells, however, began to be severely impaired 2 weeks after intracranial inoculation concurrently with the increased intracranial pressure due to developing the tumor growth. Sensitized lymphocytes obtained from intracranial and subcutaneous tumor-bearing mice were assessed for CTL (cytotoxic T-lymphocyte) activity in MLTC (mixed lymphocyte-tumor cell culture) for 18 hours by microcytotoxicity assay. The specific cytotoxicity against 203-glioma cells was enhanced when sensitized lymphocytes from intracranial and subcutaneous tumor-bearing mice were pre-cultured with optimal TCGF (20 U/ml) for over 5 days. After the treatment of sensitized lymphocytes with anti-Thy-1 monoclonal antibody and complement, however, the specific cytotoxicity of sensitized lymphocytes was eliminated almost completely. Therefore, it was thought that TCGF possesses immunoregulatory effects of enhancement of killer T-cell activity. On the contrary, TCGF had no influence on normal T lymphocytes and the growth of 203-glioma cells in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Effects of TCGF (T-cell growth factor) on experimental malignant glioma-specific killer T-cell]. 660 19

When the NGF-secreting C-6 rat glioma cells were intracerebrally injected with F98 rat anaplastic glioma cells into rats syngeneic for the F98 cells, an increased mean survival time was observed for rats developing tumors compared with those injected with only anaplastic glioma cells. Thirty percent of the rats injected with both cell types showed no signs of tumor at 90 days. Pretreatment of the anaplastic glioma cells with conditioned medium of C-6 cells did not duplicate these results unless the C-6 cells were pretreated with 17 beta-estradiol, which appears to induce secretion of an adhesion factor as well as NGF. These rats survived even longer and 33% were free of tumors at 90 days. Histological examination of tumors of the nonsurviving rats revealed that they were basically well differentiated with only small anaplastic areas remaining. Both NGF and conditioned medium from C-6 and another NGF-secreting line, S-180 mouse sarcoma, induce process formation in F98 cells and in PC12 pheochromocytoma cells, but the processes that appear following NGF exposure are morphologically different from those induced by conditioned medium. Conditioned -medium-treated cells also have a flatter appearance. In F98 cells, NGF takes longer to induce processes than does conditioned medium. The NGF-induced effects observed in both cells are neutralized by anti-NGF IgG, but those induced by conditioned media are not. Nerve growth factor (NGF) induced increased adhesiveness in F98 rat anaplastic glioma and PC12 rat pheochromocytoma cells. Conditioned media are not. Nerve growth factor induced increased adhesive-and PCuced effects observed in both cells are neutralized by anti-NGF IgG, but those induced by conditioned media are not. Nerve growth factor (NGF) induced increased adhesiveness in F98 rat anaplastic glioma and PC12 rat pheochromocytoma cells. Conditioned media are not. Nerve growth factor induced increased adhesive-and PCuced effects observed in both cells are neutralized by anti-NGF IgG, but those induced by conditioned media are not. Nerve growth factor (NGF) induced increased adhesiveness in F98 rat anaplastic glioma and PC12 rat pheochromocytoma cells. Conditioned media are not. Nerve growth factor induced increased adhesive-and PC12 cells. Anti-NGF IgG did not influence this effect on F98 cells and only partially neutralized the effect on PC12 cells, indicating that other factors may be operative in this system. Conditioned medium collected from C-6 cells pretreated with 17 beta-estradiol induced the highest degree of adhesiveness observed in both F98 and PC12 cells, and this action was unaffected by anti-NGF IgG in either case. Conditioned media from other cell lines, a variety of selected proteins, and dBcAMP did not induce increased adhesiveness. The factor responsible for this effect is nondialyzable, heat-sensitive, and ammonium-sulfate-precipitable, and its secretion appears to be stimulated by 17 beta-estradiol.
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PMID:Effect of nerve growth factor producing cells on anaplastic glioma and pheochromocytoma clones: involvement of other factors. 729 47

We have found that the small stress protein, hsp27, exists in extracts of U251 MG human glioma cells in two forms: a large or aggregated form (L-hsp27, 300-400 kDa) and a small or dissociated form (S-hsp27, < 70 kDa), as indicated by centrifugation on sucrose density gradients. Dissociation of L-hsp27 to S-hsp27 was enhanced by incubation of cells with phorbol 12-myristate-13 acetate, interleukin-1 alpha, tumor necrosis factor alpha, or okadaic acid, all of which are known to enhance or mimic the effects of phosphorylation of hsp27 without stimulation of its synthesis. Exposure of cells to chemical stressors, namely, NaAsO2 and CdCl2, also enhanced the dissociation of L-hsp27. hsp27 that had been labeled with [32P]H3PO4 in U251 MG cells was detected mostly in fractions that contained S-hsp27, and the incorporation of radioactivity to S-hsp27 was enhanced under conditions that stimulated the dissociation of L-hsp27. L-hsp27 present in the (NH4)2SO4 fraction (0-50% saturation) of cell extracts were dissociated to 32P-labeled hsp27 when incubated in the presence of [gamma-32P]ATP and Mg2+. These results indicate that the molecular configuration of hsp27 in cells is determined in part by phosphorylation and dephosphorylation of this protein by protein kinase(s) and phosphatase(s) and, moreover, that the rapid dissociation of the aggregated form of hsp27 by phosphorylation might be involved in a cellular defense mechanism for protection against stress.
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PMID:Dissociation as a result of phosphorylation of an aggregated form of the small stress protein, hsp27. 815 58


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