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D D Bigner

Publications and source records attributed to D D Bigner.

At least 235 records · Page 13Linked to original sources
PubMed1987

Effect of methylprednisolone on radiotherapy of F344 rats with avian sarcoma virus induced gliomas.

We have examined the impact of methylprednisolone acetate (MPA) on survival of F344 rats that were bearing avian sarcoma virus (ASV)-induced gliomas and that were treated optimally with radiotherapy. Toxicity of MPA (dose range of 0.2-5.0 mg/kg X 7 over 3 weeks) was first established in non-tumor bearing rats as assessed by their relative failure to gain weight. Doses of 2.0 or 5.0 mg/kg X 7 caused animals to be 21.8 or 43.9%, respectively, underweight compared with vehicle controls. In rats bearing ASV-induced gliomas, treatment with 3,000 cGY (nine fractions over a 3-week period) alone or with 0.2 or 1.0 mg MPA/kg (X 6 during the 3-week radiotherapy course) produced a significantly prolonged survival compared with that of untreated, tumor bearing rats. However, MPA did not enhance survival when given concurrently with radiotherapy; indeed, at the higher of these two doses, median survival of tumor-bearers was slightly less than with radiotherapy alone. This trend towards interference with the beneficial effects of radiotherapy was more pronounced with the highest dose of MPA studied, 5.0 mg/kg body weight X 6. These animals had a median survival time that was significantly less than that of tumor-bearers receiving radiotherapy alone, but not significantly different from untreated rats with gliomas. The possible significance of these observations is discussed.

Animals↗
PubMed1987

Hydroxyurea synchronization increases mitotic yield in human glioma cell lines.

Karyotypic studies of human gliomas are often limited by a low mitotic index and the appearance of contracted chromosomes that do not exhibit clear banding patterns. The purpose of this study was to investigate the use of hydroxyurea (HU) as a synchronizing agent using established human glioma cell lines as a model system. HU was shown to reversibly inhibit cellular replication in glioma cell lines U-251MG, D-245MG, D-247MG and D-263MG by flow cytometry on the basis of DNA content. Two-to sixfold increases were demonstrated in the mitotic index of HU-treated cultures exhibiting the greatest percentage of cells in the G2/M phases of the cell cycle. HU, therefore, promises to be an effective agent for use in short term cultures from biopsied human tumors to increase the quality of chromosome preparations in these tumors.

Cell Cycle↗
PubMed1987

Invasiveness of human glioma cell lines in vitro: relation to tumorigenicity in athymic mice.

Five established cell lines derived from human anaplastic astrocytomas or glioblastoma multiforme were tested for invasiveness into precultured chick heart fragments in vitro. Four of the cell lines (U118 MG, D54 MG, U373 MG and A172) were strongly invasive into the heart tissue. A fifth cell line, U251 MG sp, which was only tumorigenic at doses of greater than 1 X 10(8) cells in athymic mice, was non-invasive in vitro. One line, A172, was invasive but not tumorigenic in athymic mice, although a related invasive subline, D54 MG, at later passage levels was tumorigenic even at low cell doses. Invasion of the glioma cells was characterized by progressive and irreversible replacement of the precultured chick heart tissue. Both by light and transmission electron microscopy, a similar pattern of invasion was observed as earlier found with experimental rat glioma cells in the same system. Some human cell lines established from human gliomas retain invasive properties after a prolonged culture period in vitro.

Animals↗
PubMed1987

Relationship between gene amplification and chromosomal deviations in malignant human gliomas.

Biopsies of 33 malignant human gliomas were karyotyped and evaluated for amplification (more than eight gene copies per cell) of the epidermal growth factor receptor (EGFR), N-myc, c-myc, and gli genes by Southern blot analysis. Fifteen of 33 tumors showed amplification of EGFR, none had amplified c-myc, one tumor had amplified N-myc, and one had amplification of gli. Thirteen of the 16 (81%) evaluable tumors with gene amplification contained double minutes (DM), and only four of 16 (25%) tumors without demonstrable amplification contained these structures. Polysomy for chromosome #7, in contrast, occurred in 58% of tumors with EGFR amplification and 53% of tumors without amplification of the gene. Structural abnormalities of 7p occurred in two tumors with EGFR amplification and in one tumor without amplification of this gene. These studies suggest that DM are the usual locus for amplified genes (usually EGFR) in human glioma biopsies, but that structural abnormalities of 7p may be associated with EGFR amplification in a small proportion of these tumors. The presence of polysomy 7, however, probably is unrelated to amplification of the EGFR gene.

Chromosome Aberrations↗
PubMed1987

Chromosomal progression of malignant human gliomas from biopsy to establishment as permanent lines in vitro.

Karyotypes of four malignant human gliomas were followed from direct preparation and/or short-term culture through their establishment in vitro to determine whether the cultured cells maintained the original karyotypes, or were the products of selection, progression, or alteration in vitro. The karyotypes of these four human glioma-derived cell lines showed the same evolutionary pattern consisting of a doubling of the stem line or a closely related population; one line changed ploidy again to near-pentaploid. Marker types seen originally were generally retained, but new markers were acquired in the later passages. We concluded that the eventual chromosomal compositions of these four human glioma-derived cell lines were the products of karyotypic evolution, rather than simple selection of a minor population of polyploid cells.

Cell Line↗
PubMed1987

Comparative localization of glioma-reactive monoclonal antibodies in vivo in an athymic mouse human glioma xenograft model.

Radioiodinated murine monoclonal antibodies (Mabs) 81C6, Me 1-14, C12, D12, and E9, made against or reactive with human gliomas but not normal brain, and Mab UJ13A, a pan-neuroectodermal Mab reactive with normal human glial and neural cells, were evaluated in paired label studies in the D-54 MG subcutaneous human glioma xenograft model system in nude mice. Following intravenous injection in the tail vein of mice bearing 200-400 mm3 tumors, specific localization of Mabs to tumor over time (6 h-9 days) was evaluated by tissue counting; each Mab demonstrated a unique localization profile. The comparison of localization indices (LI), determined as a ratio of tissue level of Mab to control immunoglobulin with simultaneous correction for blood levels of each, showed Mabs 81C6 and Me 1-14 to steadily accumulate in glioma xenografts, maintaining LI from 5-20 at 7-9 days after Mab injection. Mab UJ13A peaked at day 1, maintaining this level through day 2, and declining thereafter. Mabs D12 and C12 peaked at days 3 and 4, respectively, and E9 maintained an LI of greater than 3 from days 3-9. Percent injected dose localized/g of tumor varied from a peak high of 16% (81C6) to a low of 5% (Me 1-14 and UJ13A). Immunoperoxidase histochemistry, performed with each Mab on a battery of primary human brain neoplasms, revealed that Mabs 81C6 and E9, which demonstrated the highest levels of percent injected dose localized/g of tumor over time, reacted with antigens expressed in the extracellular matrix. This finding suggests that extracellular matrix localization of antigen represents a biologically significant factor affecting localization and/or binding in the xenograft model used. The demonstration of significant localization, varied kinetics and patterns of localization of this localizing Mab panel warrants their continued investigation as potential imaging and therapeutic agents for human trials.

Animals↗
PubMed1987

Increased expression of the epidermal growth factor receptor gene in malignant gliomas is invariably associated with gene amplification.

Primary malignant gliomas from 63 patients were analyzed to determine the relationship between amplification of the gene encoding the epidermal growth factor receptor (EGFR) and expression of the corresponding mRNA. Twenty-four tumors were found to have amplified the EGFR gene and amplification of other genes occurred in three additional tumors. Hybridization with synthetic RNA probes was used to quantitate mRNA levels in situ. All 24 tumors with amplification of the EGFR gene had high levels of expression of this gene, while none of the 39 tumors without amplification had increased levels. This shows that, in human gliomas, large increases in the expression of the EGFR gene are invariably associated with alterations in gene structure.

ErbB Receptors↗
PubMed1987

Distribution of type VI collagen in human gliomas: comparison with fibronectin and glioma-mesenchymal matrix glycoprotein.

The distribution of type VI collagen was examined immunohistochemically in normal tissues and in 24 human gliomas and six medulloblastomas. Its localization in the neoplasms was compared with that of fibronectin and glioma-mesenchymal extracellular matrix (GMEM) glycoprotein. In normal non-neural tissues type VI collagen was demonstrated in the interstitial connective tissue and in some basement membranes. In normal brain it was localized to the vasculature, leptomeninges, and pial-glial membrane. In neoplasms type VI collagen and fibronectin codistributed in the vasculature and stromal connective tissue. The GMEM glycoprotein, as identified by monoclonal antibody (MAb) 81C6, and a related glioma-mesenchymal matrix antigen identified by MAb 2A6, were expressed not only in the tumor vasculature and connective tissue, but also within the tumor parenchyma in association with glioma cells. The staining intensity was variable in 20 malignant gliomas and weak to absent in two pilocytic astrocytomas and six medulloblastomas. An oligodendroglioma and ependymoma both expressed the 2A6 epitope, but staining with MAb 81C6 was weak to absent. The antigens identified by MAb 81C6 and MAb 2A6 represent the only recognized extracellular matrix components, other than proteoglycans, that are associated with glioma cells in vivo. As prominent constituents of the pericellular matrix, they may be involved in recognized matrix functions such as the modulation of cell adhesion and migration.

Animals↗
PubMed1987

Intravenous adenosine selectively increases blood flow to xenotransplanted intracerebral gliomas.

Adenosine was infused intravenously at 10 mumol/(kg.min) into athymic ("nude") rats with intracerebral D-54MG xenotransplanted brain tumors, in an attempt to increase tumor blood flow. Cerebral blood flow (F) was measured with 14C-iodoantipyrine and quantitative autoradiography. Mean arterial blood pressure was 95 +/- 9.4 (SE) mm Hg in the adenosine group and 112 +/- 6.0 mm Hg in the controls. Averaged mean whole tumor F was significantly higher in adenosine-treated brain tumors (117.6 +/- 20.8 ml/[hg.min]) than in controls (62.2 +/- 9.7 ml/[hg.min]). Regionally, there were significant increases of F in tumor periphery and brain around tumor, but not in tumor center or any tumor-free brain regions. Focal values of F less than 5 ml/(hg.min) were present in some necrotic regions of adenosine-treated tumors. These results, obtained in unanesthetized rats with transplanted gliomas from a human cell line, confirm our earlier observations in avian sarcoma virus-induced brain sarcomas in dogs, and suggest that adenosine or perhaps other vasodilators could be used to selectively increase the delivery of lipid-soluble chemotherapeutic drugs to brain tumors.

Adenosine↗
PubMed1987

A rapidly dividing human medulloblastoma cell line (D283 MED) expresses all three neurofilament subunits.

The majority of cells in a rapidly dividing human medulloblastoma cell line (D283 MED) are shown to express the two high-molecular-weight human neurofilament (NF) subunits, whereas a minority express the low-molecular-weight NF subunit. These three polypeptides are integral subunits of the intermediate filaments (IFs) found in normal neurons. Other cell type-specific IF proteins (keratin, desmin, and glial filament polypeptides) are not present in D283 MED cells. Further, the immunocytochemical, immunochemical and ultrastructural data suggest that the neurofilaments in these cells are abnormal, possibly because of a paucity of the low-molecular-weight NF subunit. This is the first human cell line derived from a central nervous system tumor that is capable of expressing all three NF triplet proteins. It is a unique model system for studies of normal and abnormal human NF metabolism as well as for probing the cell biology of medulloblastomas.

Animals↗
PubMed1987

Concurrent measurements of blood flow and transcapillary transport in xenotransplanted human gliomas in immunosuppressed rats.

Neonatal Fischer 344 rats were immunosuppressed with antithymocyte serum and later were given an injection intracerebrally of cells from the human glioma permanent line D-54MG. Symptomatic tumor-bearing rats were studied with double-label quantitative autoradiography to concurrently measure blood flow and a unidirectional blood-to-tissue transfer constant (K) for alpha-aminoisobutyric acid (AIB). A net extraction fraction (En) was calculated from the measured values for blood flow and K. Mean whole tumor blood flow was 53.5 +/- 4.9 ml/100 g/min (mean +/- SEM), which was significantly less than the blood flow to the tumor-free cortex (198 +/- 15.5 ml/100 g/min) but not significantly different from the blood flow in the tumor-free corpus callosum (50.6 +/- 4.3 ml/100 g/min). Mean whole tumor K-value for AIB was 5.8 +/- 0.5 ml/100 g/min, approximately 30 times the K-value for tumor-free brain. The calculated mean whole tumor En was 0.2 +/- 0.09, nearly 100 times the value for the tumor-free brain. Regionally, blood flow was lower in the tumor center and higher in its tumor periphery, although the difference was not significant. Both K- and En-values were significantly higher for the tumor center and decreased radially for the areas from center out. The values for K and En of AIB in the D-54MG gliomas are the highest of any experimental brain tumor model studied to date and indicate that in some tumor regions in this model, blood-to-tissue transport of the water-soluble compound AIB may be dependent on blood flow as well as on the permeability-surface area product of the tumor capillaries.

Aminobutyrates↗
PubMed1987

Therapeutic profile of the human glioma line D-54 MG in athymic mice.

We treated D-54 MG, an extensively characterized human glioma tumor line, in athymic mice with each of 20 antineoplastic drugs and two radiation doses. PCNU, melphalan, cyclophosphamide, and fludarabine were highly active against sc tumors. A single radiation dose of 2500 cGy produced a growth delay (T-C) of 22.0 days and four of seven tumor regressions (TRs), whereas 1500 cGy produced a T-C of 13.2 days and two of 10 TRs. Several other drugs produced smaller T-Cs and fewer TRs. With this model we can make quantitative determinations of the sensitivities of a human glioma line, permitting detailed studies of drug mechanisms.

Animals↗
PubMed1987

DNA content and chromosomes in permanent cultured cell lines derived from malignant human gliomas.

DNA content, as determined by flow cytometry (FCM), and ploidy, as determined planimetrically from chromosomes, were measured for 17 established human glioma-derived cell lines. Values obtained by these methods corresponded well for two of two near-diploid lines, two of two hyperdiploid-hypotriploid lines, four of four hypertriploid-hypotetraploid lines, two of six hypertetraploid-hypopentaploid lines, the one hyperpentaploid line and two of two multiclonal lines. For the remaining four lines, ploidy values obtained by karyotyping were more than 10% lower than those obtained by FCM. Since karyotypic ploidy was determined by planimetric measurements of the chromosomes, which corrects for deviations in chromosome size, the lower values could not be explained by large marker chromosomes. Technical problems, such as random chromosomal loss in karyotypic preparations, adherent bits of cytoplasm in nuclear preparations for FCM or differences in nuclear stainability, are possible reasons for the discrepancies. Alternatively, chromosomes in some glioma cell lines may actually contain an increased amount of DNA. FCM and karyotyping provide complementary information in the initial evaluation of cultured cell lines. For sequential studies, such as are used for monitoring cultured lines, the rapidity of FCM makes it the more practical method.

Cell Line↗
PubMed1986

Characterization of new gangliosides of the lactotetraose series in murine xenografts of a human glioma cell line.

The major mono- and disialogangliosides of the extensively characterized established human glioma line D54MG were isolated and purified from subcutaneous solid xenografts grown in athymic (nu/nu) mice. Structural determination showed that they belonged to the lactotetraosylceramide series. The sialyllactotetraosylceramide contained 90% N-glycolyl- and 10% N-acetylneuraminic acid linked in an alpha 2-3 linkage (IV3NeuGc-LcOse4Cer, IV3NeuAc-LcOse4Cer). The disialogangliosides had a previously undescribed type of structure with sialic acids linked to the terminal galactose in an alpha 2-3 linkage and to N-acetylglucosamine in an alpha 2-6 linkage. Not only did species with NeuAc or NeuGc occur, but also species with mixtures of the two sialic acids, e.g. NeuAc and NeuGc. The schematic structures of the new disialogangliosides are (Formula:see text).

Animals↗
PubMed1986

Specific chromosomal abnormalities characterize four established cell lines derived from malignant human gliomas.

The four permanent human glioma-derived cell lines reported here are the first such lines for which the karyotypes have been followed from the original biopsies through the establishment of the lines in culture. Although ploidy changes were seen, each line retained either distinctive marker chromosomes or the overall original chromosomal distribution allowing the origin of each line to be established with certainty. D-263 MG expresses glial fibrillary acidic protein, all lines except D-245 MG are tumorigenic in athymic mice, and each line displays a unique pattern with respect to in vitro growth parameters and expression of biochemically defined markers, oncofetal antigens and lymphoid-associated markers. D-245 MG and D-259 MG are able to grow in the absence of supplemental glutamine; glutamine synthetase was detected in these cell lines both by immunocytochemistry and by direct assay. Thus, the four permanent human glioma-derived cell lines described here are representative of glioma lines in their general characteristics. D-259 MG retains numerous double minute chromosomes (DMs), D-263 MG contains two marker chromosomes with breaks in 9p, and D-247 MG and D-245 MG with stemlines containing 96 and 89 chromosomes contain eight and six normal copies (respectively) of chromosome No. 7. The retention in these four cell lines of the most common chromosomal abnormalities seen in biopsies of malignant human gliomas provides the opportunity to investigate the meaning of these specific chromosomal changes.

Animals↗
PubMed1986

Chromosomal evolution in malignant human gliomas starts with specific and usually numerical deviations.

Our previous karyotypic studies of malignant human gliomas have demonstrated that their most consistent early or primary gross changes include gains of #7, losses of #10, #22, and the gonosomes, and the presence of double minutes. Karyotypes of 15 additional malignant human gliomas reported here have confirmed these observations and, by enlarging our series, we can now show that in addition to double minutes, certain other gross structural abnormalities also are clearly associated with the early evolution of this type of tumor. The most prevalent deviations are deletions and translocations involving 9p. Other chromosomes commonly involved in rearrangements are #1, #6, and #13, and less frequently #7, #11, and #16.

Adult↗
PubMed1986

Glioma-associated antigens defined by monoclonal antibodies against an avian sarcoma virus-induced rat astrocytoma.

S69-c15 is a highly immunogenic cell line derived from an avian sarcoma virus (ASV)-induced astrocytoma in F-344 rats. Monoclonal antibody (Mab) production was attempted by fusing F-344 rat splenocytes and mouse P3 X 63/Ag8.653 myeloma cells after a syngeneic immunization protocol. 336 fusion clones were screened by cell surface radioimmunoassay (CS-RIA) against the immunizing line S69-c15, rat kidney fibroblast line S203-c11 and Walker rat carcinoma line. Mabs 7G4, 9F1, 10E3 and 10E7 which reacted only with S69-c15 were chosen. Further analysis demonstrated that these Mabs reacted only with rat (13/23 astrocytomas, 2/4 gliomas, 1/11 neurinomas) or mouse (2/10 astrocytomas) neurogenic tumor cells induced by both viral and chemical agents. Reciprocal competition assays suggested that 7G4, 9F1 and 10E3 recognized the same epitope and that 10E7 reacted with a spatially close determinant. Antigen activity could not be found in adult rat tissues (brain, heart, lung, liver, kidney, spleen, thymus, intestine, muscle and peripheral nerve) and fetal brain (8, 12, 20 days gestation) by either absorption analysis or tissue staining. Preliminary characterization indicated that the epitope may be polypeptide-associated. Further antigen purification and tumor localization can be attempted with these Mabs.

Animals↗