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

A striking chemotherapeutically curative effect on tumor was obtained by means of temporary interruption of regional blood flow combined with local hyperthermia. By analyzing various basic conditions required for this system using Ehrlich tumor implanted in the hind limbs of mice, the following were found to be essentially indispensable to obtain satisfactory chemotherapeutic effects: (a) a time interval of 1 to 3 min after systemic i.v. administration of drug to the mice, (b) use of a tourniquet on the tumor-bearing mouse limb to stop blood flow, and (c) warming at 37-41 degrees (d) for a period of at least 30 to 60 min. Among the chemotherapeutic drugs tested in the present study, Carbazilquinone (NSC 134679) was the most effective because it revealed the strongest antitumor effect despite its relative innocuousness to nontumorous adjacent normal tissues. Applying the present method, a large syngeneic mouse sarcoma transplanted to the limb 7 days before the experiment also completely regressed in 6 of 9 mice.
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PMID:Temporary interruption of regional blood flow combined with local hyperthermia for cancer chemotherapy. 5 14

Cultured peripheral blood leukocytes from a woman (patient HL23) with acute myelogenous leukemia produced type-C RNA tumor viruses (HL23V). The viruses were analyzed by molecular hybridization experiments after transmission to five secondary cell culture lines. Using the criteria of molecular hybridization, we concluded that all of the transmitted virus isolates have nucleotide sequences related to the genome of simian sarcoma virus (SiSV). In addition, in agreement with data reported elsewhere, some of the transmitted viruses also have nucleotide sequences related to those of the baboon endogenous virus (BaEV). We also used molecular hybridization to ascertain whether both viruses could have originated from the patient HL23. Utilizing [3H] cDNA complementary to RNA from the separated BaEV-related component of HL23V and hybridizing this cDNA to DNA from tissues of the patient, we detected sequences related to BaEV in DNA obtained from the patient's spleen. These BaEV DNA sequences were also detectable when 125I-labeled RNA from BaEV was used as a probe. In agreement with earlier results, however, no SiSV-related sequences were detectable in the DNA of her tissues. Cytoplasmic viral-like particles, which had a buoyant density of 1.15-1.2 g/ml and were capable of synthesizing cDNA in association with a 35S RNA in vitro, were also found in the patient's fresh uncultured leukemic blood cells. cDNA synthesized by the cytoplasmic particles contained some sequences that hybridized to RNA from SiSV and, in addition, some that hybridized to RNA from BaEV. The cDNA also hybridized significantly to DNA isolated from the spleen of patient HL23 and to cytoplasmic RNA from the patient's leukocytes. These molecular hybridization results with nucleic acids obtained from the fresh blood cells of the patient, combined with the repeated isolation of similar viruses from different blood and bone marrow samples from the same patient, suggest that the virus come directly from the leukemic cell samples. The finding of BaEV-related DNA proviral sequences in the spleen of the patient strongly supports this interpretation. The failure so far to find a complete SiSV-related provirus is perplexing, but could be attributable to the existence of such a provirus in DNA of only a small population of cells in most leukemic patient.
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PMID:Primate type-C virus nucleic acid sequences (woolly monkey and baboon types) in tissues from a patient with acute myelogenous leukemia and in viruses isolated from cultured cells of the same patient. 5 61

The effect of neuraminidase treatment on the antigenicity of sarcoma I (Sal) and mastocytoma P-815-X2 cells was compared, both in terms of their reaction with various antisera (C57BL/6 anti-SaI, C57BL/6 anti-mastocytoma, rabbit and horse ALS) and complements (guinea pig, rabbit) or with sensitized lymphocytes (C57BL/6 anti-SaI, C57BL/6 anti-mastocytoma, A anti-mastocytoma). With sensitized lymphocytes the reactivity of neuraminidase-treated tumor cells was similar to that of nontreated cells. In contrast, after neuraminidase treatment, the tumor cells showed increased specific lysis with the antisera and complement. Rabbit complement was highly cytotoxic to the neuraminidase-treated cells but this nonspecific activity could be removed by absorption with agar or agarose. The results of this study would strongly suggest that neuraminidase treatment does not change the antigenic determinants of tumor cells but increases their interaction with complement after removal of negatively charged sialic acids.
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PMID:The effect of neuraminidase on the sensitivity of tumor cells toward lysis by antibody and complement or by sensitized lymphocytes. 5 38

Animals bearing either primary or transplantable tumors of avian sarcoma virus origin frequently mount cellular and humoral antitumor immune responses against both viral and nonviral antigenic determinants. This communication summarizes recent developments in this area, with special emphasis on the effector mechanisms of antitumor immunity in chickens. Among the topics considered are structural and antigenic aspects of avian leukosis and sarcoma viruses; virus-induced tumor-associated antigens; methods of in vivo and in vitro detection of tumor-associated antigens; and the relative importance of the bursal and thymic systems in avian antitumor immunity.
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PMID:Immunity against avian sarcomas: a review. 5 14

Twenty-three of 36 (64%) lung cancer patients, 19 of 36 (54%) melanoma patients and 18 of 27 (66%) sarcoma patients tested in the leukocyte migration in agarose assay against soluble extracts of histologically similar tumors showed significant inhibition of leukocyte migration. Reactivity to extracts of dissimilar tumors was low. Sera of only 1/13 (7%) lung cancer patients, 2/19 (10%) melanoma patients and 7/21 (33%) sarcoma patients were inhibited by extracts of histologically dissimilar tumors. Only 7-9% of cancer patients reacted to paired extracts of normal tissue from the tumor donors. An average of 13% of sera from normal controls reacted to tumor extracts. Stage of disease and mode of therapy appeared to have little effect on overall reactivity in this assay, although the number of patients within the various categories was small for purposes of statistical analysis. The leukocyte migration in agarose assay shows a sensitivity and specificity to tumor-associated antigens comparable to that of the older capillary tube method in general use and may facilitate performance of migration inhibition. This assay may not be useful as a prognostic test due to the lack ofcorrelation with stage of disease and treatment modality. However, its high specificity and economical use of tumor antigen suggest applications in tumor antigen purification. The use of soluble tumor antigen preparations may make it possible to purify these antigens further to increase specificity and reactivity.
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PMID:Detection of human tumor-associated antigens by the leukocyte migration in agarose assay. 6 Feb 86

An RNA-directed DNA polymerase associated with transformation-defective (td) segregant of Rous sarcoma virus (RSV) has been characterized. The enzyme required both a monovalent and a divalent cation, a sulfhydryl reducing agent, and all four deoxyribonucleoside triphosphates for the expression of maximal activity. Sensitivity of the endogenous RNA-directed DNA polymerase activity to a low concentration of pancreatic RNase indicated that the enzyme utilized the td virus endogenous RNA as template. Maximal DNA synthesis was observed in a reaction mixture of pH 8 - 8.5 at 45 C with a manganese concentration of 1 mM. The enzyme of the td virus responded to exogenous template-primers in a manner characteristic of DNA polymerase of RNA tumor viruses, and the response became substantially greater when noncomplementary precursors were omitted from the reaction mixture. The endogenous reaction kinetics were examined. Three phases of DNA synthesis could be distinguished. Evidence was obtained showing that during the third and slowest phase of DNA synthesis the reaction mixture was not depleted of precursors and that the enzyme was fully active to initiate DNA synthesis with newly-added viral or synthetic RNA templates. Comparison of TMP and dAMP incorporation kinetics suggested that at the initial phase the enzyme preferentially copies A-rich region(s) of viral RNA. A comparison was also made between the endogenous reaction of the td virus and that of its parent sarcoma virus. The pH optimum, metal ion requirements, effect of sulfhydryl agents, response to exogenous template-primers, and kinetics of DNA synthesis, were all compared. No significant difference between the reaction of the td virus and its sarcomatogenous counterpart could be demonstrated.
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PMID:Endogenous DNA polymerase of a transformation-defective rous sarcoma virus: characterization and comparison with the enzyme of the non-defective parent. 6 91

The purification of a blocking factor from the sera of tumor-bearing mice is described. Whole serum with blocking activity-the ability to inhibit specific cell-mediated anti-tumor immunity in microcytotoxicity tests-was fractionated on immunoadsorbent columns containing Sepharose-bound syngeneic normal mouse immunoglobulins and immunoglobulins from tumor-immune donors. The blocking serum was derived from mice which had carried a transplanted methylocholanthrene-induced sarcoma for 21 to 28 days. Elution of the immunoadsorbents recovered the blocking activity in a single fraction. This fraction was blocking activity in a single fraction. This fraction was radiolabeled and analyzed by SDS gel electrophoresis and Sephadex G-200 column chromatography. The active component of the blocking serum was shown to be a polypeptide of m.w. 56,000. Specificity testing implied that the factor was likely to be either tumor antigen or an antigen-specific suppressor molecule.
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PMID:Purification and partial characterization of a tumor-specific blocking factor from sera of mice with growing chemically induced sarcomas. 6 92

Tumors were induced by Kirsten sarcoma virus (KiSV) in an inbred guinea pig, strain 13. The tumor cells were established in culture and characterized. The KiSV-induced sarcoma cells were virus-free and nonproducing; however, they contained resuable sarcoma genome. A type B guinea pig retravirus was readily activated from the tumor cells after induction with 5-bromodeoxyuridine (BUDR). BUDR induction of guinea pig retravirus was further enhanced by treatment with dexamethasone, a synthetic glucocorticoid hormone.
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PMID:Characterization of virus-free guinea pig tumors induced by Kirsten sarcoma virus. 6 43

Three of 42 (7%) monkeys given aflatoxin B1 (AFB1) for longer than 2 years have developed primary malignant neoplasms of the liver. Liver biopsies performed at intervals during aflatoxin administration revealed that neoplasia was preceded by pathologic lesions of the liver, including toxic hepatitis, proliferation of pseudotubules, and hyperplastic nodules. Serum alpha-fetoprotein levels, monitored in one of the monkeys by radioimmunoassay, paralleled tumor growth and recurrence of the hepatocellular carcinoma. Normal serum alpha-fetoprotein levels were noted for a monkey with hemangioendothelial sarcoma. Our results implicate AFB1 as a liver carcinogen in monkeys and add additional support to the hypothesis that humans exposed to this substance may be at risk of developing liver cancer.
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PMID:Carcinogenicity of aflatoxin B1 in rhesus monkeys: two additional cases of primary liver cancer. 6 57

The chemotherapeutic action of Bleomycin, applied at a dosage which induced only a non-specific tumor inhibition on HRS-sarcoma, was potentiated by combination with inosine. This combination, without increasing toxicity, effected both a significant tumor inhibition and a significant curative action.
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PMID:Potentiation of the chemotherapeutic action of bleomycin by combination with inosine on HRS-sarcoma. 6 12


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