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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sixty-five patients with malignant brain tumors were treated with a combination of BCNU (100 mg/m2 qd X 1) and procarbazine (100 mg/m2 qd X 14); the cycle was repeated in 1 month and then on a 6-week schedule with procarbazine being given for 21 days. Forty-five patients had malignant gliomas (glioblastoma multiforme, anaplastic astrocytoma, malignant glioma, or gemistocytic astrocytoma) and were evaluated as a group. All patients had either shown evidence of tumor regrowth after previous surgery and/or radiotherapy, or had deep unbiopsied tumors presumed to be malignant gliomas. Of these 45 patients, 13 of 45 (30%) were judged to be unequivocal responders and an additional eight of 45 (17%) were designated as probable responders. The median duration of clinical response was 34 weeks for responders and 20 weeks for probable responders. The combination of BCNU and procarbazine, therefore, was somewhat inferior to a previous combination of procarbazine, CCNU, and vincristine.
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PMID:BCNU (NSC-409962) and procarbazine (NSC-77213) treatment for malignant brain tumors. 17 10

Groups of F-344 rats were inoculated with the Bratislava-77 strain of avian sarcoma virus (B-77 ASV) within 24 hours of birth, at 9 days of age, or between 97 and 119 days of age. Intracranial tumors developed in each age group. Multiple tumors with mixed histologic patterns developed in rats inoculated at 1 or 9 days of age. Solitary tumors with a uniform histologic pattern developed in rats inoculated as adults. On the basis of light and electron microscopic study, the majority of tumors in each age group were classified as astrocytomas and divided into either poorly differentiated, gemistocytic, pilocytic, or polymorphic varieties. The polymorphic astrocytomas were most common among neonatally inoculated rats, while the pilocytic astrocytomas were most common among rats inoculated as adults. Ultrastructural characteristics of astrocytes, including gap junctions and 7- to 9-nm filaments, were present in the majority of tumors in each age groups. Astrocytomas induced in adult rats were remarkable for the presence of extensive basement membrane alone the astrocytic cell surfaces. Intracytoplasmic virus-like particles (R particles) were common in the tumor cells. These virus-like particles are morphologically distinct from C-type B-77 ASV, and no morphologic evidence of C-type virus replication was observed in any of the tumors.
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PMID:The fine structure of intracranial neoplasms induced by the inoculation of avian sarcoma virus in neonatal and adult rats. 17 28

The Feulgen-DNA cytophotometry was applied for studies of 31 rat cerebellum tumors induced by 9, 10-dimetyl-1,2-bensantracene. Most of these gliomas (22) were astrocytomas of different grades of malignancy. The histological diagnosis of other tumors was: glioblastoma -- 4, oligoastrocytoma -- 2, oligodendroglioma -- 1, gliosarcoma 1. The majority cells of 26 tumors had diploid or paradiploid DNA quantity, 4 tumors (1 astrocytoma, 3 dedifferentiated astroyctomas) had triploid modal classes. The tetraploid modal class and a large number of polyploid cells were found only once for glioblastoma multiforme. A supposition was made that drastic changes of ploidy could arise for the second time during the process of tumor evolution. The authors failed to show any exact differences in the ploidy of gliomas in rats with athyreosis or hyperthyreosis, and in the ploidy of somatic cells in control animals.
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PMID:[Cytophotometric determination of DNA concentration in the cells of experimental brain tumors. II. Primary tumors of rat cerebellum induced by 9, 10-dimethyl-1, 2-benzanthracene]. 18 64

Rats bearing primary tumors of the brain induced by avian sarcoma virus (ASV) were studied with the migration-inhibition factor (MIF) assay for the presence of cell-mediated immunity to tumor-associated antigens. Astrocytomas and sarcomas of the brain were induced in 34 neonatal F344 rats by the intracerebral inoculation of Bratislava-77 ASV. At weekly intervals from 4 to 9 weeks after the inoculation with virus, peritoneal exudate cells (PEC) from rats bearing brain tumors were tested an an MIF assay against soluble and KCl-treated extracts of a syngeneic, ASV-induced sarcoma. Incubation of the PEC with a soluble extract of syngeneic liver or with a KCl extract of a syngeneic, chemically induced tumor served as controls. Of 14 rats tested against the soluble tumor extract, 6 (43%) had statistically significant inhibition of migration (P less than or equal to 0.05). Of 23 animals tested against the KCl extract, 16 (70%) had significant inhibition. Immunity to the KCl extract was significant in most rats at each period. Ten rats were tested against a KCl extract of a hamster ASV-induced tumor; 7 gad significant inhibition of migration. None of 3 tested against a soluble extract of a syngeneic, chemically induced tumor had significant inhibition. Rats bearing ASV-induced brain tumors displayed cell-mediated immunity to tumor-associated antigen or antigens of ASV-induced tumors, which could be solubilized.
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PMID:Cellular immunity in rats with primary brain tumors: inhibition of macrophage migration by soluble extracts of avian sarcoma virus-induced tumors. 18 22

Oxidoreductases were studied histochemically in 162 cases of neuroectodermal tumors. In order of decreasing activity in the cytoplasma these enzymes could be arranged as follows: NADH diaphorase, lactate dehydrogenase, NADPH diaphorase, glutamate dehydrogenase, glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, succinate dehydrogenase, malate dehydrogenase. The weak activity of Krebs cycle enzymes and the relatively strong activity of other oxidoreductases, particularly of lactate dehydrogenase, permits to conclude that glycolysis prevails over oxidative processes in neuroectodermal tumor cells. But this should not be interpreted as a decrease of the Krebs cycle enzymes in astrocytoma and oligodendroglioma cells as compared with their parent cells because the latter themselves display a weak activity of these enzymes. A real decrease of Krebs cycle enzyme activity was established only for tumors, the parent cells of which are characterized by a strong (in choroid-papillomas) or moderate (in ependymomas) activity of these enzymes. Many neuroectodermal tumors, in particular those of astrocytic origin, demonstrate a certain correlation between the amount of cytoplasm and oxidoreductase activity. This results in enzymatic polymorphism of the tumor tissue. A certain similarity was established of the oxidoreductase activity in tumor cells and in reactive hypertophic astrocytes. This indicates that both tumor cells and reactive astrocytes may in certain conditions utilize similar mechanisms of increased metabolism. The oxidoreductase activity correlates not with the grade of anaplasia but with different directions of anaplasia reflected in different variants of neuroectodermal tumors. The concept "anaplasia" includes not only certain degrees of dedifferentiation of tumor cells but, as it has been shown histochemically, also an increase of metabolic processes in the tumor cell cytoplasma.
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PMID:Histochemistry of oxidoreductases, enzymatic polymorphism and anaplasia of neuroectodermal tumors. 18 68

This study further characterizes the morphological and in vitro properties of human neoplastic cells derived from one Grade IV cerebral astrocytoma and one Grade III cerebellar astrocytoma. Light microscopic observations performed weekly over a four month period revealed two morphologically indistinguishable cell populations in each of the tumor cultures. Scanning electron microscopy demonstrated the presence of microvilli, blegs, and ruffles on the cell surfaces of both tumors; however, these topographical features were more prominent in the cultures derived from the Grade III cerebellar astrocytoma. Scanning electron microscopy may provide a useful tool for the further morphologic classification of human astrocytomas.
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PMID:Topographical anatomy of human cerebral and cerebellar astrocytomas in vitro. 18 6

Of 488 central nervous system neoplasms occurring in children over a 39-year period, 467 were intracranial and 21 were intraspinal. The most common intracranial neoplasms were astrocytoma (28%), medulloblastoma (25%), ependymal neoplasm (9%), craniopharyngioma (9%), and glioblastoma multiforme (9%). The median age at diagnosis was 6 years with a male-to-female ratio of 1.3:1. Overall mean survival was 53.4 months and varied greatly relative to the type of tumor and the location. Of the intraspinal neoplasms the most frequently noted were the astrocytoma (47%) and the ependymal neoplasma (24%). The median age at diagnosis was 10 years with a male-to-female ratio of 1:1. The average survival from diagnosis (54.1 months) was comparable to that of intracranial neoplasms. Detailed analyses of each histological type of tumor relative to age at diagnosis, sex, anatomical location and survival from diagnosis are reported for both intracranial and intraspinal neoplasms.
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PMID:Central nervous system tumors in children. 20 64

Twenty-nine primary intraspinal neoplasms in children observed between 1936 and 1975 in Connecticut are reviewed. Most of them were gliomas: 45 per cent astrocytoma, 24 per cent ependymal neoplasm, 10 per cent glioblastoma multiforme and 7 per cent glioma. Symptoms, physical findings and therapy are reviewed.
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PMID:Intraspinal neoplasms in children. 20 2

Experimental animal models resembling most human brain tumor types can be induced by exposure to oncogenic viruses or chemical carcinogens: Astrocytomas and glioblastoma multiforme can be produced experimentally by intracerebral injection of oncornaviruses, whereas medulloblastomas, choroid plexus papillomas, and ependymomas can be induced by the papovaviruses. Adenoviruses have been utilized to cause medulloepitheliomas, neuroblastomas, and retinoblastomas. All three groups of viruses can result in sarcoma production. Gliomas represent the primary tumor type induced in the brain by chemical carcinogens. These autochthonous tumor systems are reviewed, with emphasis on methods, tumor type, latency period, advantages, and disadvantages. In addition, recent investigations of molecular events involved in neoplastic transformation by chemical carcinogens are summarized.
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PMID:Chemical- and virus-induced brain tumors. 20 37

Various modes of therapy, alone or in combination, have had little effect in improving the survival of patients with glioblastoma multiforme. Recently, in a pilot study, 34 patients with glioblastoma were treated by fast-neutron-beam irradiation of the whole brain. Following treatment, the patients became steroid-dependent and pursued a gradual downhill course with increasing obtundation. Although there was no improvement in the length or quality of survival of these patients, neuropathological studies in the 13 patients who came to autopsy showed the following: 1) extensive coagulative necrosis of much of the tumor mass; 2) dense infiltration by collagenous connective tissue; 3) minimal phagocytic reaction; 4) marked reduction in the amount of viable tumor; 5) abnormal astrocytic proliferation, which may represent either astrocytoma or a radiation-induced bizarre gliosis, and 6) areas of gliosis and white matter degeneration in the brain stem, remote form the tumor site. These observations suggest that continued efforts to further refine this mode of therapy for glioblastoma are warranted.
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PMID:Fast-neutron irradiation of glioblastoma multiforme. Neuropathological analysis. 20 33


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