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D D Bigner

Publications and source records attributed to D D Bigner.

At least 325 records · Page 18Linked to original sources
PubMed1981

Comparative permeability of different glioma models to horseradish peroxidase.

Seven different experimental glioma models were studied to determine their capillary permeability to horseradish peroxidase. The models were the autochthonous ASV-viral model, intracerebral (ic) and (sc) injections of rat 9L and RG-2 tumor cell lines, the sc rat S-69C15 tumor cell line, and human glioblastoma cell lines in nude mice. The ASV-viral model showed an average HRP permeability of 63% of tumor volume, the ic RG-2 tumors were 100% permeable, and the ic 9L tumors were 41% permeable. The permeability of the marginal zone (brain-tumor interface) showed similar variation from group to group. In contrast, all of the sc tumors were 100% permeable regardless of the cell line used to create the tumors. Our results show the variability between these glioma models, and suggest that RG-2 ic gliomas and all sc gliomas should be optimal to assess the tumoricidal effect of drugs, because access to the tumor compartment from the vascular compartment is complete.

Animals↗
PubMed1981

Anaplastic human gliomas grown in athymic mice. Morphology and glial fibrillary acidic protein expression.

The morphologic and biochemical characteristics of human surgical biopsy specimens taken from 17 patients with anaplastic human gliomas and of athymic mouse-grown tumors derived from them were examined. Fourteen were categorized as glioblastoma multiforme, one as an anaplastic astrocytoma, one as a recurrent glioblastoma multiforme, and one as a gliosarcoma. Fifteen of 17 tumors stained positively immunohistochemically for glial fibrillary acidic protein (GFAP), a glial-specific marker. When portions of the 17 surgical biopsy specimens were injected into the flank subcutaneous space of athymic mice, 16 produced tumors; different portions of a single biopsy specimen were used to establish three separate tumor lines; in toto, 18 tumor lines were established. Mouse-borne tumors contained various proportions of fibrillary and protoplasmic astrocytes, gemistocytes, small anaplastic cells, and multinucleated giant cells. Some were more homogeneous than the human tumors from which they were derived, while others contained a mixed population similar to that of the original biopsy specimen. Of these initial 18 tumors, 16 were stained for GFAP and 14 contained from fewer than 5% to almost 100% GFAP-expressing cells. Ten of the tumor lines were studied in serial passage, several demonstrating increased cellularity with increased passage. GFAP expression was followed through serial passage, and 7 of 10 tumor lines continued to express it, often in reduced amounts, and 2 of 10 ceased expression, one (the gliosarcoma) never having expressed it. These data demonstrate that while athymic mouse-borne human anaplastic gliomas retained some features of the human tumors from which they were derived, they varied from one another morphologically. These mouse-borne tumors also continued to evolve, often changing their levels of GFAP and demonstrating increased cellularity with passage.

Animals↗
PubMed1981

Endothelial cell surface expression and binding of factor VIII/von Willebrand factor.

Factor VIII/von Willebrand factor (FVIII/vWF), a glycoprotein molecular complex found in human plasma, has been demonstrated by cell membrane fluorescence to be present on the surface of cultured human umbilical cord vein endothelial cells. The endothelial nature of these cells was established by electron-microscopic studies that revealed the presence of Weibel-Palade bodies in virtually all cells cultured. A newly developed radioreceptor assay was used to detect FVIII/vWF in the medium taken from these endothelial cell cultures; FVIII/vWF concentration in the medium samples increased with time in culture. FVIII/vWF binding studies showed no significant FVIII/vWF-specific binding to endothelial cell surfaces and did not corroborate a previous report suggesting a FVIII/vWF-specific receptor on human umbilical cord vein endothelium. The presence of FVIII/vWF on endothelial cell membranes and the lack of receptor-mediated binding suggests that the FVIII/vWF either has been absorbed non-specifically to the cell surface or is an integral part of the endothelial cell membrane.

Blood Coagulation Factors↗
PubMed1980

Tumorigenic cell culture lines from a spontaneous VM/Dk murine astrocytoma (SMA).

One of the few spontaneous gliomas in inbred animals, the VM/Dk spontaneous murine astrocytoma (SMA), has seen limited use. Previously restricted to an in vivo system, the SMA was only transplantable intracerebrally (IC) using nonquantifiable suspensions of normal brain and tumor tissue. Prior attempts at establishing permanent tumorigenic SMA cell lines have not succeeded; tumorigenicity was lost during serial in vitro passage. We have established three different cell culture lines from a serially IC-transplanted SMA and two from tumors that arose from intraperitoneal (IP) injection of the IC-transplanted SMA. In contrast to previous cell cultures and transplantable lines of SMA, all five cell lines are not only tumorigenic IC but subcutaneously (SC) as well. Astrocytic feature are present in three of five lines to varying degrees, evidenced by in vitro and in vivo morphology, response to dibutyryl cyclic AMP (db-cAMP), and the presence of neuroglial fibers: None of the lines express CNPase, S-100, or GFA proteins in significant amounts. P560, highly tumorigenic and possessing the most astrocytic features of the five lines, extends the use of the spontaneous astrocytoma system of the inbred VM/Dk mouse strain by allowing quantitative in vivo and in vitro experiments.

Animals↗
PubMed1980

Experimental gliomas: an autoradiographic study of the endothelial component.

Autochthonous gliomas were induced in rats by intracerebral inoculation of avian of avian sarcoma virus and studied by 3H-thymidine autoradiography. Parenchymal glial tumor cells had a 3H-labeling index (LI) of 3.0 to 13.6%. Endothelial cells in tumor blood vessels had an LI of 2.6 to 34.3%, independent of and in most instances higher than the LI of the glial tumor. Endothelial cells of normal blood vessels had an average LI of 0.3%. This study documents the high proliferative rate of the endothelial cells in anaplastic experimental gliomas, and emphasizes the necessity for seeking direct, incontrovertible evidence to determine whether or not the rapidly proliferating endothelial cells are malignant.

Animals↗
PubMed1980

Treatment of autochthonous rat brain tumors with fractionated radiotherapy. The effects of graded radiation doses and of combined therapy with BCNU or steroids.

The avian sarcoma virus-induced glioma model in rats was used to evaluate radiation dose response (survival curves), giving fractionated treatments to the whole head. Groups of 14 to 20 rats received total doses of 2300, 4600, or 5750 rads over 2, 4, or 5 weeks, respectively. Median group survival times were compared to controls and to each other. All doses of radiation significantly prolonged survival with reference to control. The 4600- and 5750-rad doses were significantly more effective than the 2300-rad dose. In another series of experiments, BCNU chemotherapy (10 mg/kg) was combined with 2300 and 4600 rads radiation therapy. Synergism of therapies was demonstrated. Methylprednisolone acetate (2 mg/kg twice weekly over 4 weeks) alone did not affect survival curves, and its combination with 4600 rads radiation therapy negated the prolongation of survival achieved with 4600 rads alone.

Animals↗
PubMed1979

Heterotransplantation of human craniopharyngiomas in athymic "nude" mice.

Surgical biopsies from 2 human craniopharyngiomas were transplanted subcutaneously into 6 athymic "nude" mice. Morphologically characteristic craniopharyngiomas grew in 5 of these animals. In 4 animals growth was sufficient to allow transplantation into a second generation of animals. In all, 11 craniopharyngiomas were present at autopsy in the 14 animals into which the tumors had been transplanted. The tumors that grew in the animals had the same adamantinomatous architecture, epithelial nests, and keratinized nodules that were present in the original surgical sample and that are characteristic of human craniopharyngiomas. It may be possible to study growth characteristics and therapeutic sensitivities of human craniopharygniomas growing in "nude" mice.

Animals↗
PubMed1979

Synergism between BCNU and irradiation in the treatment of anaplastic gliomas. An in vivo study using the avian sarcoma virus-induced glioma model.

The therapeutic effects of irradiation, BCNU, or combined irradiation and BCNU were studied in the avian sarrcoma virus (ASV)-induced glioma model in rats. Whole-head orthovoltage radiation therapy was given in six equal fractions over 2 weeks, and BCNU was administered intraperitoneally as a single dose of 10 mg/kg. Two series of experiments were performed in order to duplicate the results. In Series I, the median survival times of the experimental groups, in days after randomization were as follows: control group (no treatment), 69; group receiving 200 rads, 84 (p less than 0.05); group receiving BCNU, 80.5 (p less than 0.1); and group receiving 2000 rads + BCNU, 112 (p less than 0.001). In Series 2, the median survival times were: control group, 73.5; group receiving 2300 rads, 85 (p less than 0.01); group receiving BCNU, 92.5 (p less than 0.025); and group receiving 2300 rads + BCNU, 123.5 (p less than 0.001). In both series, combined therapy was significantly better than either radiation or BCNU alone. This is the first time that a synergistic effect of BCNU and irradiation has been reported in an in vivo brain-tumor model and supports the clinical use of this combination in the treatment of malignant gliomas.

Animals↗
PubMed1979

Dihydrofolate reductase in primary brain tumors, cell cultures of central nervous system origin, and normal brain during fetal and neonatal growth.

Dihydrofolate reductase (DHFR) was measured during the development in rats of brain tumors induced following inoculation with avian sarcoma virus. Increasing activity of this enzyme in brain was correlated with the course of primary brain tumor growth. The specific activities of DHFR in primary human brain tumor tissues were comparable to those found in avian sarcoma virus-induced brain tumors in rats. Specific activities of DHFR in cell cultures derived from human and rat primary intracranial gliomas and sarcomas were up to 6 times those found in adult rat liver. The presence of DHFR in neoplasms of central nervous system origin is relevant to the development of folate antagonists which, unlike methotrexate, can readily cross the blood-brain barrier. In normal developing rat brain, DHFR specific activity was high in embryos at 19 days of gestation and declined thereafter, until at 20 days after birth the activity was very low. The methotrexate titration assay was used to measure enzyme levels in the brains of fetal and newborn rats, and good correlation with the spectrophotometric assay was observed. The pattern was different in liver, showing maximum activity 11 days after birth and retaining high activity in adult liver. Both the cofactor requirement and the sensitivity to methotrexate indicate that the enzyme in the brain is DHFR.

Animals↗
PubMed1978

Glial-mesenchymal tropism of in vivo avian sarcoma virus neuro-oncogenesis in rats.

Intracerebral inoculation of avian sarcoma virus (ASV) in postnatal animals induces gliomas and sarcomas but no neuronal tumors. High titer Bratislava-77 strain ASV was inoculated intracerebrally in fetal F-344 rats between 17 and 20 days of gestation: a time of active neuronal proliferation. Following birth inoculated rats developed gliomas and sarcomas but no neuronal tumors. The results are evidence that the glial-mesenchymal tropism of in vivo ASV neuro-oncogenesis is independent of stage of neurocytodifferentiation at inoculation.

Animals↗
PubMed1978

General immunocompetence of rats bearing avian sarcoma virus-induced intracranial tumors.

The mitogenic responsiveness of spleen cells obtained from avian sarcoma virus-inoculated Fischer 344 rats was studied. Sixty % of the rats had astrocytomas, 13% had sarcomas, 7% had mixed gliosarcomas, and 20% had no evidence of tumors. Only spleen cells from rats bearing astrocytomas had significantly diminished responses to phytohemagglutinin and concanavalin A (Con A) when compared to control responses. The decreased responsiveness observed with phytohemagglutinin was limited to the optimal concentration range (10 and 20 microgram) while a broader concentration of Con A (0.01 to 50 microgram) induced significant suppression. Moreover, a more profound immunosuppression was observed with Con A. The results also demonstrated that spleen cells from rats with the largest astrocytomas exhibited the greatest suppression. From the results of this study, it appears the avian sarcoma virus-induced astrocytoma in rats is an immunological parallel of the human disease based on the loss of general immunological competence as assessed by responsiveness of lymphocytes to phytohemagglutinin and Con A.

Alpharetrovirus↗
PubMed1977

The role of the subependymal plate in glial tumorigenesis.

We have studied the sequential morphological events of glial tumorigenesis in neonatal dogs, using high titer subgroup C Bratislava-77 Avian Sarcoma Virus, given as 0.01 ml by intraventricular inoculation. The cells of the subependymal plate are those which seem to form the gliomas; cytoplasmic alterations are evident within 24 h after inoculation and microfoci of gliomas, contiguous with the subependymal plate of the lateral ventricles, are visible within 7 days. Independent tumors are present by the 10th post-inoculation day. These studies support the hypothesis of Globus and Kuhlenbeck, which implicates the cells of the subependymal palte in glial tumorigenesis.

Animals↗
PubMed1977

The role of the subependymal plate in avian sarcoma virus brain tumor induction: comparison of incipient tumors in neonatal and adult rats.

F-344 rats were inoculated intracerebrally at 1 and at 133 days of age with the Bratislava-77 strain of avian sarcoma virus. Groups of rats were sequentially sacrificed following inoculation so that early stages of microtumor formation could be evaluated. In neonatally inoculated rats incipient tumors developed in the subependymal region of the lateral ventricles in close juxtaposition to clusters of poorly differentiated germinal cells. Among these animals microtumors were detected as soon as 2 weeks after inoculation; by 4 weeks post-inoculation all rats inoculated at 1 day of age had tumors. In contrast among rats inoculated as adults incipient tumors developed in the cerebral cortex away from the subependymal region but adjacent to the locus of inoculation. Incipient tumors were uncommon in rats inoculated as adults during the first 2 months after inoculation.

Animals↗