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)

Myosin has been isolated from the clonal lines of murine neuroblastoma and rat glioma cells. Partial characterization of the two cellular myosins indicates that both possess the following properties: (1) the same elution position as rabbit skeletal muscle myosin by Sepharose 4B chromatography; (2) the presence of heavy (molecular weight about 200,000) and light subunit polypeptides by sodium dodecyl sulfate polyacrylamide gel electrophoresis; (3) EDTA and Ca2+ activated but Mg2+-inhibited ATPase activity in 0.6 M KCl; and (4) binding to rabbit skeletal muscle F-actin which is inhibited by Mg2+-ATP. For both mouse neuroblastoma and rat glioma cells, approximately 0.5-1.5% of the total cell protein is present as myosin. Cellular myosin appears to be indistinguishable in quantity and biochemical properties regardless of whether it is isolated from monolayer or suspension neuroblastoma cells.
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PMID:Isolation and characterization of myosin from cloned rat glioma and mouse neuroblastoma cells. 13 25

The glycosaminoglycans (GAG) of human cultured normal glial and malignant glioma cell lines were studied using 35S-sulphate or 3H-glucosamine as markers. 35S-labelled GAG were assayed by precipitation with cetylpyridinium chloride; 3H-labelled sulphated GAG and 3H-labelled hyaluronic acid were quantitated after separation on a DEAE-cellulos column. The net production of GAG and the distribution, composition and turnover of GAG were similar in all of the normal cell lines tested, but showed a great variability in the malignant cell lines. Most of the glioma cell lines produced more hyaluronic acid and less sulphated GAG than the normal cell lines, but exceptions were noted. The GAG of the trypsin susceptible (pericellular pool of normal glial cells consisted mainly of heparan sulphate with only minor amounts of other GAG. The analogous material of most glioma cells showed hyaluronic acid as the major GAG. Material liberated by trypsin from EDTA-detached cells (membrane fraction) was enriched in heparan sulphate as compared to the entire pericellular pool. Substrate attached material (SAM) left with the plastic dish after EDTA treatment of normal cultures was rich in heparan sulphate, whereas SAM of glioma cells lacked heparan sulphate or showed greatly reduced amounts of this component. Release of newly synthesized GAG to the extracellular medium was a rapid process in the normal cells but was more or less delayed in the glioma cells. The extracellular medium of the malignant glioma cultures was consistently poor in dermatan sulphate, as compared to that of normal cultures.
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PMID:A comparative study of glycosaminoglycans in cultures of human, normal and malignant glial cells. 43 97

The glycosaminoglycans of human cultured normal glial and malignant glioma cells were studied. [35S]Sulphate or [3H]glucosamine added to the culture medium was incorporated into glycosaminoglycans; labelled glycosaminoglycans were isolated by DEAE-cellulose chromatography or gel chromatography. A simple procedure was developed for measurement of individual sulphated glycosaminoglycans in cell-culture fluids. In normal cultures the glycosaminoglycans of the pericellular pool (trypsin-susceptible material), the membrane fraction (trypsin-susceptible material of EDTA-detached cells) and the substrate-attached material consisted mainly of heparan sulphate. The intra- and extra-cellular pools showed a predominance of dermatan sulphate. The net production of hyaluronic acid was low. The accumulation of 35S-labelled glycosaminoglycans in the extracellular pool was essentially linear with time up to 72h. The malignant glioma cells differed in most aspects tested. The total production of glycosaminoglycans was much greater owing to a high production of hyaluronic acid and hyaluronic acid was the major cell-surface-associated glycosaminoglycan in these cultures. Among the sulphated glycosaminoglycans chondroitin sulphate, rather than heparan sulphate, was the predominant species of the pericellular pool. This was also true for the membrane fraction and substrate-attached material. Furthermore, the accumulation of extracellular 35S-labelled glycosaminoglycans was initially delayed for several hours and did not become linear with time until after 24 h of incubation. The glioma cells produced little dermatan sulphate and the dermatan sulphate chains differed from those of normal cultures with respect to the distribution of iduronic acid residues. The observed differences between normal glial and malignant glioma cells were not dependent on cell density; rather they were due to the malignant transformation itself.
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PMID:Composition and distribution of glycosaminoglycans in cultures of human normal and malignant glial cells. 68 54

Melphalan, a nitrogen mustard derivative of the neutral amino acid L-phenylalanine, was transported across the rat blood-brain barrier by the large (L-system) neutral amino acid transporter in tumor-bearing brain, but no evidence for blood-brain barrier transport by the alanine-serine-cysteine system carrier was obtained in the present study. The ability of melphalan to inhibit phenylalanine uptake was compared in rats implanted with two experimental CNS tumors: the C-6 glioma (a model of primary brain tumors) and Walker carcinoma (a model of metastatic brain tumors). The melphalan concentration which caused 50% inhibition of blood-brain barrier (BBB) phenylalanine uptake (Ki) was 0.49 +/- 0.18 mM in the Walker tumor, compared with 0.46 +/- 0.19 mM in the contralateral control brain. In the ipsilateral hemisphere (Ki = 0.59 +/- 0.25 mM) and contralateral hemisphere (Ki = 0.45 +/- 0.19 mM), drug entry was also via the neutral amino acid transporter. In C-6 gliomas (Ki = 0.77 +/- 0.20 mM) and contralateral control brain (Ki = 0.84 +/- 0.29 mM), melphalan also inhibited BBB phenylalanine transport. A major finding was that, at melphalan concentrations greater than 1.0 mM, BBB permeability of radiolabeled indium (chelated to EDTA) increased in proportion to melphalan concentration. In the contralateral hemisphere of rats implanted with C-6 gliomas, brain extractions of indium-EDTA measured 3 to 4% in the absence of drug, 5 to 6% at 2.5 mM melphalan, and 9 to 10% at 5 mM melphalan. A similar phenomenon was observed in the nontumoral brain regions of rats implanted with Walker carcinoma cells. In normal (nonimplanted) rats, melphalan's inhibition (Ki = 0.29 mM) of phenylalanine and tryptophan (Ki = 0.20 mM) uptake was confirmed, and brain extraction of sucrose (a nonspecific marker which does not penetrate the intact BBB) was observed to increase in proportion to melphalan concentration. We conclude that melphalan not only enters the brain via the neutral amino acid transporter, but at higher concentrations (greater than 1 mM) may open the blood-brain barrier in a nonspecific manner.
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PMID:Melphalan penetration of the blood-brain barrier via the neutral amino acid transporter in tumor-bearing brain. 172 74

A large-animal model was developed to facilitate the noninvasive investigation of the effect on the human glioma-derived D-54 MG (glioblastoma multiforme) continuous cell line of a variety of therapeutic regimens. Twenty random-bred male cats were inoculated intracerebrally with 1 x 10(7) D-54 MG tumor cells after being initiated on one of three preparatory regimens of cyclosporin A p.o. Reproducible success of D-54 MG xenotransplantation (100%, 6 of 6 cats) was achieved only after pretreatment with 120 mg cyclosporin A p.o. (24-30 mg/kg) daily for greater than or equal to 10 days prior to tumor implantation. High-performance liquid chromatography-derived whole blood cyclosporin A 12-h trough levels of greater than or equal to 640 ng/ml were seen in successful implants. Lesions ranging from 2 to 20 mm in diameter were seen in cats sacrificed 27-44 days after implantation with no growth seen in control animals. Histopathological examination revealed the tumors to be well-circumscribed anaplastic intracerebral tumors with some invasion into surrounding host parenchyma. Perivascular lymphocytic cuffing was observed, but intratumoral lymphocytic infiltration was minimal. Gadolinium-EDTA-enhanced nuclear magnetic resonance imaging provided accurate tumor localization in T1-weighted images (TE 26 ms; TR 600 ms). Biochemical tests of kidney, liver, and hematological function were within normal limits, although 10% (2 of 20) of the animals developed gingival hyperplasia, and 5% (1 of 20) developed intussusception. The reproducible growth of the D-54 MG human glioblastoma cell line in a large-animal model eliminates many of the limitations associated with the standard nude mouse/rat model, thereby providing a novel test bed for a variety of imaging modalities as well as for drug immunoconjugate localization and toxicity studies.
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PMID:Development of a large-animal human brain tumor xenograft model in immunosuppressed cats. 201 4

The isolation of a metalloproteinase secreted by a rat glioma cell line (BT5C) in serum-free media is described. After affinity purification, the activity was present as a double band with Mr 86000 and 76000 both of which required CaCl2 for activity. The enzyme was able to degrade gelatin but not casein. It was unable to degrade native types I, III, IV and V collagens but their denatured counterparts were degraded. Using a radiolabel release assay the enzyme was inhibited by EDTA, 1:10 phenanthroline and TIMP confirming that it belongs to the family of metalloproteinases. Its activity was not affected by either serine or cysteine protease inhibitors. The proteinase was activated by APMA but was unaffected by trypsin treatment.
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PMID:Isolation and characterization of a metalloproteinase secreted by rat glioma cells in serum-free culture. 224 53

Human glioma cells obtained from established cell lines (Tp-276MG, Tp-301MG, Tp-378MG, Tp-483MG and U-251MG) were analyzed for the presence of ion channels with the tight-seal voltage clamp technique. The current-voltage relation revealed a marked inward rectification at hyperpolarizing voltages, due to the presence of inward rectifying K-channels in cells from all studied cell lines. These channels were conducting when the membrane potential was more negative than the K-equilibrium potential. The slope conductance for the inward K-currents (gKi) was affected both by [K+]i and [K+]o. gKi was proportional to [K+]o raised to 0.35 or 0.50, of which the larger value was measured in the presence of low [K+]i (25 mM). The rectification was not significantly different in cells perfused with Mg-free EDTA-buffered internal solution. Tl+ was 3.5 times more permanent than K+. gKi was blocked by Cs+ (1 mM) in a voltage-dependent way (more effective in the hyperpolarized membrane), and by Na+ (154 mM) depending on voltage and time. From measurements of unitary current events in membrane patches (outside out or cell attached) the conductance of the single inward rectifying channel was estimated to be 27 +/- 7 pS. This type of ion channel may be important for K-uptake by glial cells and hence for the K-homeostasis in the brain.
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PMID:Inward rectifying potassium channels in human malignant glioma cells. 246 12

The ability of the dinitrilotetraacetates EDTA, CDTA, and EGTA to inhibit the growth of rat C6 glioma cells was not proportional to their chelational stability constants, suggesting a nonchelational mechanism of action. Ion antagonization studies supported this hypothesis. Growth inhibition did not appear to be caused by an EDTA-ion coordination complex. The chemical structure of the DNTAs suggests that they might act by: increasing zeta potential electronegativity and altering local physical properties; macromolecular crosslinking; and disrupting hydrogen bonds and hydrophobic interactions. Interestingly, their ability to inhibit growth paralleled their hydrophobic surface areas.
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PMID:Nonchelational cell growth inhibition by EDTA. 309 2

Using three lines of human normal glial cells and four established lines of human malignant glioma cells we have studied cell spreading following seeding onto glass and plastic substrata. The cells were detached with EDTA and trypsin, suspended in EMEM with 10% calf serum and studied with time-lapse, phase-contrast cinematography in suspension and during attachment and spreading. Cells were fixed and prepared for light microscopy while in suspension and during the spreading process. They were also prepared for scanning and transmission electron microscopy at different times during spreading. The projected areas of stained cells, in suspension and at different stages of spreading, were measured morphometrically and the results compared statistically. The glial cells in suspension were often found to retain somewhat their shape from the previous monolayer. They spread radially outwards with even lamellar cytoplasm and peripheral ruffling, as a group more quickly than the malignant glioma cells. They also became polarized and started to translocate in a shorter time. The glioma cells were spherical in suspension and characterized by pronounced blebbing of the cell surface. Blebbing continued during spreading and was finally replaced by ruffling at the edge. The cells spread like the glial cells radially outwards but the lamellar cytoplasm was occasionally somewhat irregular. Cells from the glioma lines spread as groups slower than the glial cells but with individual rates for the different lines. One of the glioma lines appeared to spread more thinly than the glial cells. Cells which sedimented on top of other cells could not spread. Aggregations of cells spread and became polarized more quickly than single cells in all cases.
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PMID:The spreading of human normal glial and malignant glioma cells in culture. Studies on standard culture conditions. 390 65

Characterization of muscarinic acetylcholine receptors in acinar cells from rat pancreas and lacrimal and parotid glands was achieved by binding of the reversible muscarinic antagonist [3H]quinuclidinyl benzilate (QNB) and the specific alkylating reagent [3H]propylbenzilylcholine mustard (PrBCM) to intact acini or dispersed acinar cells. Binding studies with [3H]QNB showed that acinar cells from pancreas contain 26,400, from parotid 21,400, and from lacrimal gland 25,700 binding sites/cell. To assess molecular size of the receptor in each gland, acini were prepared by digestion with purified collagenase and singly dispersed acinar cells were prepared by a combination of digestion with crude collagenase, hyaluronidase, and alpha-chymotrypsin and divalent cation chelation using EDTA. Muscarinic receptors on acini or dispersed cells were covalently labeled with 5 nM [3H]PrBCM, solubilized directly in hot sodium dodecyl sulfate buffer, and resolved by polyacrylamide gel electrophoresis. When solubilized acini were electrophoresed, a major labeled peak was observed on gels along with a smaller peak of lower apparent molecular weight. For pancreatic acini, the apparent molecular weights of these peaks were 117,600 and 85,700; for parotid acini, 104,800 and 74,500; and for lacrimal acini, 87,200 and 63,100. Addition of muscarinic antagonists to the labeling medium abolished both peaks. When dispersed acinar cells were labeled, the larger peak was eliminated, and all radioactivity was concentrated in a single peak: 87,600 for pancreas, 78,000 for parotid gland, and 62,800 for lacrimal gland. Digestion of prelabeled acini with the mixture of enzymes used to produce dispersed acinar cells similarly shifted all radioactivity into this second peak. Limited digestion of acini or dispersed cells with 1 mg/ml of papain resulted in the disappearance of these higher molecular weight peaks and the appearance of a broad peak at Mr = 40,000. Cells of nonepithelial origin, IM-9 lymphocytes and NG108 neuroblastoma X glioma hybrids, also were labeled with [3H]PrBCM and electrophoresed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Muscarinic acetylcholine receptor structure in acinar cells of mammalian exocrine glands. 398 Apr 74


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