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Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Synthesis, localization and release of serotonin (5-HT) were studied in cholinergic neuroblastoma X glioma NG108-15 cells. The content of 5-HT and tryptophan hydroxylase activity rose substantially when hybrid cells were differentiated by prostaglandin E1 plus theophylline, or dibutyryl cAMP. Localization of [3H]5-HT taken up into differentiated NG108-15 cells was examined by electron microscopic radioautography. Silver grains were observed mostly in neurites, indicating that neurites of differentiated NG108-15 cells are the preferential uptake site of [3H]5-HT. Statistical analysis of the results of electron microscopic radioautographs revealed that silver grains had a high affinity for dense core vesicles of 60-170 nm diameter, though grains were also located over endoplasmic reticulum, mitochondria and cytosol. Dense core vesicles were abundant in neurites, and less numerous in cell bodies of the hybrid cells. [3H]5-HT taken up into NG108-15 cells was released by potassium stimulation in the presence of Ca2+. The results indicate that NG108-15 hybrid cells manifest many properties comparable to those of serotonergic neurons.
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PMID:Localization of [3H]serotonin in neuroblastoma x glioma hybrid cells. 408 12

Karyotypes of three malignant cell lines derived from Wistar and WKA/Mk fetal rat glioblasts, transformed by murine sarcoma virus (MSV-M-os) as well as those of four cell lines derived from C6 glioma cells of Wistar origin, retransformed by MSV-M-os, were analyzed in early culture passages. The C6 line had a modal number of 42 chromosomes with a normal male karyotype, and only a minor population of cells with 43 chromosomes. The modal chromosome number in every transformed glial cell line shifted from 42 to 43. The G-banding pattern revealed consistent chromosome abnormalities. Structural chromosome changes occurred in one chromosome No. 2 (2q-) and in one No. 4 (4q+). The cells with a 43 chromosome karyotype showed trisomy of chromosome No. 12 and its heteromorphism, a finding also confirmed by silver staining. Identical chromosome changes were found in transformed C6 cell lines. A further interesting feature was that all malignant cells had different distribution patterns of silver-stained nucleolar organizer regions (Ag-NORs) among particular chromosomes (Nos. 3, 11 and 12) from normal cells, showing an increased frequency of chromosome No. 12 with Ag-NORs. These results suggested that the gain and/or loss of specific segments involved in chromosomes Nos. 2, 4 and 12 contain(s) genes favorable to malignant transformation in rat glial cells.
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PMID:Specific chromosome changes associated with viral transformation of rat glial cells. 714 43

To assess the diagnostic and prognostic relevance of nucleolar organizer regions (AgNORs) the silver-stained AgNOR structures of 46 human gliomas (22 primary gliomas, 21 first and 3 second recurrences) from 28 patients were counted and measured. Surgical specimens of two neuropathological centres were included in this retrospective study. The tumours were classified into 8 groups according to WHO criteria of diagnosis and grading and their state of recurrence: 1: primary glioma grade II; 2: primary glioma grade III; 3: glioblastoma grade IV; 4: first recurrence of glioma grade II; 5: first recurrence of glioma grade III; 6: first recurrence of glioblastoma grade IV; 7: second recurrence of glioma grade II and 8: second recurrence of glioma grade III. AgNOR numbers demonstrated a positive correlation with increasing histological grade. Similarly, higher levels of AgNORs were in general found in recurrent tumours compared to primary tumours with few exceptions in groups, in which few numbers only could be analyzed. The present study demonstrates the utility of evaluating AgNOR in assessing malignant gliomas and indicates that recurrences have a higher proliferative potential than original tumours. The problems of standardization of the AgNOR technique are especially crucial for the retrospective evaluation of fixed and embedded pathological material.
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PMID:Nucleolar organizer regions (AgNORs) in primary and recurrent gliomas. A retrospective study. 751 77

To assess the possible role of the DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) in resistance of brain neoplasms to the clinically important chloroethylating agent 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), we quantitated MGMT activity, BCNU survival, and the effect of ablating MGMT activity on the sensitivity of 14 human medulloblastoma- and glioma-derived cell lines. BCNU resistance, measured as 10% survival dose (LD10), differed eightfold among the lines. Elimination of measurable MGMT activity with the substrate analogue inhibitor O6-benzylguanine (O6-BG) revealed a variable but limited contribution of MGMT to survival. In no case did O6-BG reduce LD10 by more than 3.4-fold. In contrast, O6-BG reduced the LD10 for N-methyl-N'-nitro-N-nitrosoguanidine up to 31-fold in the same cell lines (Bobola MS, Blank A, Berger MS, Silber JR, Mol Carcinog 13:70-80, 1995). Variability in BCNU survival, manifested as a sevenfold range of LD10, persists after measurable MGMT was eliminated, indicating that another mechanism or mechanisms is operating to limit cytotoxicity. Cells alkylated while suspended in growth medium are more resistant to BCNU and display less dependence on MGMT than cells treated while proliferating on a plastic substratum. When alkylated in suspension, most of the lines are either unresponsive to O6-BG or contain a subpopulation that did not respond to O6-BG. Our results demonstrate that BCNU resistance is multifactorial and that MGMT makes a modest contribution to resistance in our lines.
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PMID:Contribution of O6-methylguanine-DNA methyltransferase to resistance to 1,3-(2-chloroethyl)-1-nitrosourea in human brain tumor-derived cell lines. 760 83

Opioid peptides, Met5- and Leu5-enkephalin, are known endogenous ligands for the delta-opioid receptor (DOR) associated with opioid analgesia at the spinal level. To determine the cellular sites for DOR-mediated actions, we examined the ultrastructural localization of DOR and Met5-enkephalin (ME) in the spinal cord by combining immunoperoxidase and immunogold-silver labeling for antibodies against DOR and ME, respectively. Antibodies for DOR localization were raised in guinea pig against peptide 34-47 (p34), an amino acid sequence within the extracellular N-terminus of the DOR recently cloned from mouse neuroblastoma glioma (NG-108) cells. Selective immunoperoxidase labeling for DOR was detected by light microscopy in NG-108 cells and in the lamina I and II of the dorsal horn of the spinal cord (C2-C4). Electron microscopy of these spinal laminae revealed that the majority of the punctate varicosities seen by light microscopy were axon terminals. delta-opioid receptor-like immunoreactivity (DOR-LI) in axon terminals was most prominently associated with large dense core vesicles, and sometimes seen along the membranes of small clear vesicles and segments of the plasmalemma. A semiquantitative analysis of dually labeled sections revealed that of the terminals showing DOR-LI, 23/102 (23%) also contained Met5-enkephalin-like immunoreactivity (ME-LI). Conversely, 23/35 (66%) of the terminals showing ME-LI also showed DOR-LI. In addition to the presynaptic localization, selective postsynaptic densities within dendrites were also occasionally (9%) immunolabeled for the opioid receptor. These results provide the first ultrastructural evidence that DOR may serve autoreceptor functions on ME terminals as well as presynaptic modulation of other transmitters in the dorsal horn of the rat spinal cord. Additionally, the vesicular localization of DOR-LI in axon terminals suggests the involvement of these organelles in the transport of the receptors to the plasma membrane.
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PMID:Ultrastructural immunolabeling shows prominent presynaptic vesicular localization of delta-opioid receptor within both enkephalin- and nonenkephalin-containing axon terminals in the superficial layers of the rat cervical spinal cord. 766 82

The nuclear matrix is operationally defined as the structure that remains after nuclei are extracted with nonionic detergent and with high salt and are digested with nucleases. Thus the nuclear matrix protein composition is critically dependent on the isolation conditions. We have compared nuclear matrices isolated from human cell lines by two different methods. First, isolated nuclei were extracted as above to obtain a matrix fraction. This method showed a substantial contamination by cytoplasmic intermediate filaments but immunization of mice resulted in antibodies recognizing nuclei and the mitotic spindle apparatus. Second, a nuclear matrix fraction was made by extracting whole cells as above and dissolving the residue in urea and dialysing against an assembly buffer to precipitate intermediate filament proteins (Fey, E. G. and Penman, S., Proc. Natl. Acad. Sci. USA 1988, 85, 121-125). Such fractions showed complex protein patterns in silver-stained two-dimensional gels for four cell lines: HeLa, MCF-7, SW13 and the U333CG/343MG glioma line. While some proteins in the nuclear matrix fraction were common to all cell lines, others appeared cell-line specific. Two-dimensional gels and the immunoresponse in mice again showed contamination of these preparations with cytoplasmic proteins. These results clearly show the difficulties associated with protein chemical analysis of nuclear matrices: the preparations have substantial cytoplasmic contamination, the polypeptide composition is extremely complex and the yield of individual polypeptides is low. Thus, without further experiments one cannot say which proteins are true nuclear matrix components.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Gel electrophoretic analysis of nuclear matrix fractions isolated from different human cell lines. 805 79

The biological nature of optic gliomas is controversial, with some considering them benign hamartomatous lesions, and others believing them to be true neoplasms. We evaluated the use of colloid silver impregnation of nucleolar organizer region-associated proteins (AgNORs) in making this distinction. Thirty-one optic gliomas, 14 optic nerve meningiomas, and a single case of giant cell glioblastoma multiforme (monstrocellular glioma) of the optic chiasm were stained for AgNORs and counted in a masked fashion. The optic gliomas contained 2.01 +/- 0.09 AgNORs per nucleus, similar to that of optic nerve meningiomas (2.15 +/- 0.15) and our previously reported counts for diffuse fibrillary astrocytoma (2.22 +/- 0.10), and significantly more than that of reactive astrocytosis (1.18 +/- 0.02). Six of the seven optic gliomas examined had compound AgNORs, a feature associated with malignancy in other tumour types. AgNOR counts did not correlate with clinical features, including those seen during the post-operation course. These data suggest that optic gliomas may be true neoplasms, and not benign hamartomas.
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PMID:Nucleolar organizer regions in optic gliomas. 829 81

The delta opioid receptor has been purified, in an active form, by succinylmorphine affinity chromatography. The receptor was purified partially from bovine frontal cortex and to apparent homogeneity from neuroblastoma x glioma hybrid NG108-15 cells as observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by silver staining. Antiserum to the purified bovine receptor inhibited ligand binding to membranes and immunoprecipitated a 58 kDa protein from NG108-15 cells. Reconstitution of the receptor with lipids enhanced binding by 9-fold. The 58 kDa band protein after electroelution and reconstitution with lipids also showed specific binding, indicating that the receptor could be renatured even after SDS-PAGE in an appropriate lipid environment.
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PMID:Purification and reconstitution of the delta opioid receptor. 839 46

A total resection of a left frontal lobe tumor in a 26-year-old man revealed differentiated ganglioglioma with small foci of atypical glial cells exhibiting mild atypia. Six and one-half years later, a large, well-demarcated tumor recurred; at that time, histological analysis revealed both typical ganglioglioma and highly cellular anaplastic areas, the latter predominating. Although the patient subsequently underwent total and subtotal resections, radiation therapy, and chemotherapy, tumors continued to recur at progressively shorter intervals and he died at the age of 35 years. Biopsies of tissue obtained at the last three resections and the autopsy revealed only anaplastic tumor cells. Routine histological examinations indicated that these tumors were uniformly composed of undifferentiated cells. However, pathological studies using immunohistochemical analysis, electron microscopy, and immunoblot analysis demonstrated that a small number of recurrent anaplastic cells had astrocytic features. Results of Ki-67/MIB-1 labeling and silver nucleolar organizer region counts for those cells were high for glial tumors. A retrospective study of the initial tumor showed slightly high MIB-1 labeling for atypical glial cells. This case is characterized by pathological findings of recurrent tumors that correspond to an unusual form of malignant glioma exhibiting slight astrocytic differentiation. The present case suggests that a longer follow-up period ( > 5 years) is necessary in cases of ganglioglioma with mild atypia and that careful examinations, including proliferating potential analysis of initial tumor cells, could be important for the diagnosis and treatment of ganglioglioma.
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PMID:Recurrent anaplastic ganglioglioma: pathological characterization of tumor cells. Case report. 884 72

The DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) confers resistance to therapeutic methylating and chloroethylating agents in human brain tumor-derived cell lines. In this work, we assayed MGMT activity in 152 adult gliomas to establish correlates with patient and tumor characteristics. We also assayed MGMT in histologically normal brain adjacent to 87 tumors to characterize changes in activity accompanying neurocarcinogenesis. MGMT activity was detectable in 76% (115 of 152) of tumors, ranging approximately 300-fold from 0.30 to 89 fmol/10(6) cells (180-57,000 molecules/cell). Mean activity was 6.6 +/- 13 fmol/10(6) cells and varied 4-fold among diagnostic groups. The mean for oligodendrogliomas was 2-fold lower (P < 0.03), and for mixed oligodendroglioma-astrocytomas, the mean was 4-fold lower (P < 0.006) than for astroglial tumors. Twenty-five % of gliomas had no detectable MGMT activity (Mer- phenotype; < 0.25 fmol/10(6) cells or 150 molecules/cell). Glioma MGMT was inversely correlated with age (P < 0.01), consistent with the observed age dependence in the progenitor tissue of brain tumors (J. R. Silber et al., Proc. Natl. Acad. Sci. USA, 93: 6941-6946, 1996). Neither MGMT activity nor proportion of Mer- tumors differed by sex. Glioma MGMT was correlated with degree of aneuploidy (P < 0.006) but not with fraction of S-phase cells. Mean activity in tumors was 5-fold higher than in adjacent histologically normal brain (5.0 +/- 7.6 versus 1.1 +/- 1.9 fmol/10(6) cells; P < 0.001). Notably, elevation of tumor activity was observed in 62% of tissue pairs, ranging from 2-fold to > 105-fold. Moreover, 64% of Mer- normal tissue was accompanied by Mer+ tumor. These observations indicate that expression of MGMT activity is frequently activated and/or increased during human neurocarcinogenesis, and that the enhancement is not related to proliferation per se. Significantly, enhanced MGMT activity may heighten the resistance of brain tumors to therapeutic alkylating agents.
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PMID:O6-methylguanine-DNA methyltransferase activity in adult gliomas: relation to patient and tumor characteristics. 950 Apr 73


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