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

Male CD2F1 mice bearing an MCAM-7 transplant in the right leg underwent surgical excision of the tumor and showed specific resistance to subsequent challenges with that identical tumor line. An in vivo response to tumor-specific antigens (MCAM-7 antigen) solubilized by hypertonic potassium chloride was measured by 24-hour footpad swelling response in male CD2F1 mice immunized to the tumor from which the antigens were extracted. These observations suggested that the transplantable MCAM-7 fibrosarcoma could produce immunity toward the solubilized MCAM-7 tumors antigens and that this tumor immunity could be measured by footpad swelling response to injection of the solubilized antigens, an indication of cell-mediated immunity. The footpad swelling response was also monitored in relation to the extent of tumor growth. Similar techniques have been applied to patients bearing adenocarcinoma of the prostate for whom skin testing was substituted for the measurement of footpad swelling in animals. Four of 10 patients, who had known prostate carcinoma and were given intradermal injections of soluble tumor antigens extracted from their tumors, exhibited a cutaneous, delayed type hypersensitivity response to the injected autologous tumor extracts. No positive reactions were observed in response to solubilized components of control tissues, including BPH. These observations suggest that some patients bearing adenocarcinoma of the prostate can exhibit an immunologic response to specific antigens present in their neoplasms.
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PMID:Specificity of cell membrane antigens in prostate cancer. 8 64

The effects of three different dosage schedules on both therapeutic effect and pulmonary toxicity of bleomycin were studied in mice. Therapy was assessed by both survival and decreased tumor size in mice bearing Lewis lung carcinoma. Lung toxicity was estimated in nontumored mice as increases in lung collagen content by measuring lung hydroxyproline concentrations. In the first set of experiments, bleomycin injections twice daily (low-dose, high-frequency) produced a significant (34%) increase in lifespan over controls, whereas the same total dose given twice weekly did not result in increased survival. Both schedules produced pulmonary toxicity. Continuous sc infusion of bleomycin via an osmotic minipump was compared to these two schedules of intermittent injection. Identical total doses of drug were administered in all three schedules. Continuous infusion for 7 days produced marked inhibition of tumor growth (T/C = 16%), which was significantly better than twice weekly or ten-times weekly injection of the same total dose. Furthermore, at a total dose of 40 mg/kg of bleomycin, continuous infusion did not result in measurable pulmonary toxicity, whereas both schedules of bolus injection produced significant increases in lung collagen content. Thus, continuous infusion of bleomycin improved its therapeutic effect against Lewis lung carcinoma and also reduced its pulmonary toxicity.
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PMID:Improved therapeutic index of bleomycin when administered by continuous infusion in mice. 8 69

Tansplantability, growth, morphology, and function of xenotransplanted human tumors, such as carcinomas of the lung, liver, breast, choriocarcinoma, and blastomas of the liver, lung, kidney, and uterus, are described. From the tumor take rate, it is clear that xenotransplantation cannot be used for the study of every human tumor: slow-growing tumors are difficult to analyze, and functioning adenomas and low-grade malignant carcinomas are at present almost impossible to study by this approach. From the authors' transplantation experience, tumor antigenicity to nude mice with no T-cell function, either tumor specific or species specific, was suspected. Therefore, the growth in nude mice may not equate to that in the human body. The stroma of the transplanted tumor, which is most likely of mouse origin, might also alter the growth rate, as it did the histology of some tumors. Another possible hindrance that has not been described in the text is the mouse endogenous virus. Serially transplanted human tumors are often infected with C particles, which could well influence the tumor growth and character. In spite of the presence of some factors unfavorable for the study of human tumors through xenotransplantation, it has, nevertheless, been clearly shown that the nude mouse/human tumor system is a very useful tool for functional analysis of tumors in relation to growth, differentiation, and morphology, such as eutopic or ectopic production of various hormones, AFP, normal serum proteins, colony-stimulating factor, erythropoietin, and so on. This system can be employed to elucidate the production of many other biologically active and inactive substances by a variety of tumors and their effects on the host in the future and should provide better understanding of human cancers. Attempts to induce differentiation and to change the biologic behavior of xenotransplanted human malignant tumors have failed so far, except for induced dormancy of breast carcinoma under unfavorable hormonal conditions. This line of investigation may have particular import on cancer research, particularly in relation to the biology and treatment of human cancers.
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PMID:Growth, morphology, and function of xenotransplanted human tumors. 9 41

Mice bearing the BW7756 hepatoma were passively immunized using rabbit antiserum to murine alpha-fetoprotein (AFP) administered in constant or increasing doses. Control tumor-bearing mice were inoculated with saline or nonimmune rabbit serum (NRS) (constant or increasing doses), or were left untreated. The tumor growth curves from mice receiving constant or increasing doses of anti-AFP or constant doses of NRS showed suppression of hepatoma growth; but in both groups of anti-AFP-treated mice this was accompanied by gross anatomical changes, including necrosis, more extensive than in the NRS-treated or other control mice. AFP blood levels roughly paralleled the tumor growth responses. Since an immunological response against the rabbit serum was elicited in the host, it is possible that circulating immune complexes play some role in tumor suppression. Changes observed in liver- and spleen-to-body weight ratios may also reflect a response to circulating immune complexes.
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PMID:Immunobiologic studies in hepatoma-bearing mice passively immunized to alpha-fetoprotein. 9 91

The inhibitory effect of vitamin A on tumor establishment and growth has been studied in two animal models. The C57L/J hepatoma, when placed in C57L/J mice receiving inoculations of vitamin A, showed slow growth and the hosts had significantly prolonged survival over untreated mice. The V-2 carcinoma, when implanted in the corneas of New Zealand white rabbits receiving injections of vitamin A, showed decreased vascular response in the limbic vessels. The absence of an induced vascular response prevents vascularization of the tumor and subsequent tumor growth. The evidence suggests that vitamin A may exert its inhibitory effect by modifying the normal vascular response to neoplastic tissue.
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PMID:Vitamin A effect on tumor angiogenesis. 9 97

In vivo immunogenicity and in vitro species-specific membrane antigens in tumor cells treated or untreated with glutaraldehyde (GA) were studied. Two different syngeneic Syrian hamster transplantable tumor cell lines (spontaneous liver cancer and SV40-induced sarcoma) not only lost immunogenicity after GA treatment but were responsible for enhancement of test-tumor growth in immunized animals. In vitro mixed hemadsorption test used for determination of species-specific membrane antigens in Syrian hamster, green monkey and interspecies hybrid cells revealed drastic alteration of antigens on the membrane of cells treated with GA.
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PMID:Sensitivity of TSTA and species-specific cell membrane antigens of tumor cells to glutaraldehyde treatment. 9 20

Macrophage accumulation during the growth of a peritoneal ascites and three s.c. tumors in two animal species was analyzed and correlated with the capacity of the same tumor-bearing host to respond to inflammatory stimuli at sites distant to the tumor. Two of the three s.c. tumors induced systemic defects in macrophage accumulation; the tumor that did not (P-815 mastocytoma) did depress inflammation when transplanted to the peritoneal site. Macrophage accumulation within different tumors varied but, for a given tumor, it occurred in proportion to tumor growth when systemic inflammatory reactions were normal. However, the tumor to macrophage ratio increased dramatically and concurrently with onset of the generalized defect in macrophage inflammatory responsiveness. Accordingly, we concluded that macrophage mobility tested at remote sites is indicative of inflammatory events within the tumor. However, the antiinflammatory effect directed against macrophages is probably not a significant factor in tumor emergence since the required number of tumor cells was large and variable between not only tumors but also sites of transplantation.
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PMID:Concurrent depression of tumor macrophage infiltration and systemic inflammation by progressive cancer growth. 9 32

Congenitally athymic (nude) and hereditarily asplenic (Dh/+) mice were painted with dimethylbenzanthracene (DMBA) to compare skin tumor development in these immunodeficient animals with their immunologically normal littermate controls. Papillomas were induced in all groups of mice. However, nude and Dh/+ mice were significantly more resistant than their normal littermates to tumor induction. Furthermore, the number of papillomas/mouse and the total tumor incidence were significantly greater in control mice and the latency period for tumor appearance was shorter and the tumor growth rate greater in normal mice compared to their immunodeficient littermates. Finally, nu/+ skin transplanted to nude mice and then painted with DMBA behaved in similar fashion as nude skin. These findings, when discussed in terms of target organs for DMBA, suggest a major role for the immune system in stimulating papilloma induction.
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PMID:DMBA induced papillomas in congenitally athymic (nude) and hereditarily asplenic (Dh/+) mice: contrasts and comparisons with immunologically intact littermates. 9 36

The tubulin-binding affinities of podophyllotoxin and 12 related compounds have been compared with the effectiveness of these drugs in three assays of antitumor activity: (1) The mastocytoma assay of inhibited tumor cell growth in vitro; (2) the 37 sarcoma assay of tumor remission in vivo; and (3) the Stentor regeneration inhibition assay which detects a requirement for microtubule polymerization. The results indicate that there is a positive Spearman rank correlation coefficient between the inhibition constant for the binding of colchicine to tubulin in the presence of these compounds and the effectiveness of the compounds in the three assays of tumor growth inhibition. It is suggested that tubulin-binding assays may be a useful step in the screening of podophyllotoxin-like compounds suspected of disrupting mitosis by binding to microtubule protein.
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PMID:Correlation of tubulin-binding and antitumor activities of podophyllotoxin analogs. 10 3

Listeria monocytogenes-mediated tumor inhibition was studied in strain 13 guinea pigs by using a methylcholanthrene-induced fibrosarcoma (MCA-1). Mixtures of Listeria and tumor cells in ratios of 1:100, 1:200, or 1:400 (Listeria:MCA-1 cells) led to significant suppression of tumor growth. Intralesional injection of tumors on day 6 posttransplantation led to the regression of a highly significant number of tumors. Animals receiving injections of Listeria, either in a mixture with tumor cells or intralesionally, displayed enhanced skin test reactivity to a tumor extract. Tumor regressors were resistant for at least 2 to 3 months after the initial transplant to rechallenge with MCA-1 cells. Thus, with this particular tumor-host system, Listeria was successfully employed as an antitumor agent with no visibly detrimental side effects to the host.
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PMID:Antitumor activity of Listeria monocytogenes on a guinea pig fibrosarcoma. 10 6


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