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

In vitro lymphocyte stimulation by mitomycin-C-blocked tumor cells has been used to demonstrate tumor-specific antigens in syngeneic murine systems and to follow the evolution of tumor immunity with the tumor-bearing state. Mitomycin-blocked tumor cells stimulated syngeneic lymphocytes from normal mice, from those bearing small tumors (less than 1 cm in diameter) and from tumor-immune mice, sensitized by tumor-cell inoculation and subsequent tumor removal, to undergo increased DNA synthesis as measured by the incorporation of tritiated thymidine. However, lymph-node cells from mice bearing tumors over 1 cm in diameter appeared to be maximally stimulated in vivo and incapable of further stimulation by the same tumor cells in vitro. This was reflected by the progressively increasing background levels of nucleic acid synthesis with the length of tumor-bearing and the size of the tumor. Although lymph-node cells from mice with large tumors did not respond to the same tumor cells in vitro, they did have normal responses to PHA. Within 7-14 days of surgical removal of the tumor, specific lymphocyte responsiveness and background activity returned to previous normal levels, but reinoculation with 10-6 tumor cells resulted in progressive tumor growth and loss of specific in vitro responsiveness when the second tumor had reached the critical size of 1 cm in diameter. Brief exposure of tumor-immune lymph-node cells to a soluble antigen extract of the same tumor resulted in a marked increase in DNA synthetic activity compared to that obtained after exposure to a different tumor extract, muscle extract or medium alone underwent stimulation when cultured with mitomycin-blocked tumor cells. However, normally responsive tumor-immune lymph-node cells, after brief exposure to a soluble antigen extract of the same tumor, initially underwent increased DNA synthesis, but were incapable of further stimulation by mitomycin-blocked tumor cells. Tumor antigen, alone or complexed with antibody, was also demonstrated in the sera of mice bearing large tumors and is thought to be responsible for the refractoriness of lymph-node cells from these mice to further stimulation in vitro. These experiments demonstrate that tumor size and the consequent antigen load to which the tumor-bearing animals is subjected have a profound effect on tumor-specific lymphocyte responsiveness.
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PMID:Refractoriness of lymph-node cells from tumour-bearing animals. 4 43

Mitomycin C-treated ascites cells of Ia antigen-positive GRSL14 tumor cells and spleen cells from GRSL14 tumor-bearing mice stimulated lymphocyte proliferative responses in normal syngeneic GR spleen cells. Furthermore, mitomycin C-treated T cells purified from spleen cells of tumor-bearing mice also stimulated normal GR spleen cells. Anti-Ia sera inhibited the stimulating ability of tumor cells and of spleen cells of tumor-bearing mice. These data suggest a role for I region gene products in immune surveillance for syngeneic tumors.
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PMID:Immune response-associated antigens on mouse leukemia cells. II. Anti-Ia sera inhibit the MLR reaction between normal GR spleen cells and syngeneic spleen cells of GRSL tumor-bearing mice. 15 53

Gastrointestinal cancer has proved exceedingly resistant to chemotherapy efforts. 5-Fluorouracil (5-FU) accepted as standard treatment, has provided only infrequent and incomplete antitumor effects. Other drugs as the nitrosoureas BCNU and CCNU or Mitomycin C do not match the effectiveness of 5-FU. Improvement in frequency of tumor regression have been recorded for gastric carcinoma with combinations of 5-FU and BCNU and 5-FU, adriamycin and Mitomycin C and for colorectal carcinoma with combination of 5-FU, methyl-CCNU and vincristine. There are also suggestions that such combination chemotherapy may produce increased survival when compared to untreated patients. The combination of 5-FU and streptozotocin in carcinoid tumors or adriamycin in primary hepatoma may be of some effectiveness.
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PMID:[Chemotherapy of gastrointestinal cancer (author's transl)]. 15 93

Regional tumor-draining lymph nodes of 11 of 14 patients with urological tumors and one of four controls studied contained suppressor cell precursors that could be activated by concanavalin A (Con A) to suppress the proliferative response of autologous lymphocytes to Con A. In contrast, no suppression of lymphocyte proliferation by lymph node cells that were not activated with Con A was observed in four patients tested. The suppressive effect was not due to decreased viability or increased release of cold thymidine by Con A-activated cells nor to alteration in the time course of the proliferative response of Con A-activated cells. Mitomycin C treatment of lymph node cells 24 hr after activation did not abrogate their suppressive activity. Peak suppression was observed after 72 hr in culture. The amount of suppression measured could be maximized by treatment of suppressor cells with mitomycin C 24 hr after activation and by washing the cells immediately before pulse labeling with tritiated thymidine. The concentration of Con A required to produce peak suppression varied from patient to patient with optimal doses ranging from 5 to 25 microgram/ml.
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PMID:Concanavalin A-inducible suppressor cells in regional lymph nodes of cancer patients. 15 24

Hamsters vaccinated with adenovirus-transformed cells, modified by acetoacetylation or concanavalin A treatment, or with small numbers of living cells were partly or completely protected against challenge with 3 times 10-6 living cells. Treatment of vaccine cells with iodoacetate, Mitomycin C, neuraminidase plus Mitomycin C did not produce efficient vaccines. Herpes simplex virus-transformed cells treated by any of these procedures did not prevent, and frequently even enhanced, the growth of the homologous living cells; enhancement was often greater in female than in male hamsters. Protective and enhancing vaccines did not induce a different level of cell-mediated immunity, as detected by lymphocytotoxicity tests, which were positive for both homologous transformed cells and nontransformed hamster cells. In contrast, specific complement-dependent cytotoxic antibodies active only on adenovirus-transformed cells were induced by the protective acetoacetylated vaccine prepared from adenovirus-transformed cells; these antibodies were not present after nonprotective vaccinations. The appearance of herpes simplex virus tumors was delayed by treatment with the immunostimulant, Levamisole, or by preimmunization with Newcastle disease virus grown in SV40-transformed cells, but not by Newcastle disease virus grown in herpes simplex virus-transformed cells. Thus, only nonspecific treatments were able to impede herpes simplex virus tumor growth, while protection against adenovirus tumor was accompanied by specific cytotoxic antibodies.
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PMID:Comparison of the immunogenicity of hamster cells transformed by adenovirus and Herpes simplex virus. 16 94

Although advanced gastrointestinal cancer is the most commonplace problem encountered by the medical oncologist, this group of diseases has proved exceedingly resistant to past chemotherapy efforts. 5-Fluorouracil (5-FU), accepted by some as standard treatment, had provided only infrequent, incomplete, and fleeting antitumor effects, which are probably more than counterbalanced by its gastrointestinal, mucocutaneous, and hematologic antihost effects. There is no evidence that any manipulation of route or schedule of administration provides any improvement in the therapeutic ratio of 5-FU. There is no evidence that this drug contributes to patient survival when used at any stage of any type of gastrointestinal carcinoma. The search for alternative single drugs to 5-FU has been disappointing. The nitrosoureas and Mitomycin C produce occasional regressions, but they do not match the meager effectiveness of 5-FU; and they, in addition, present the difficult problem of cumulative bone marrow suppression. Recent trials with combination regimens have given some indication that the long stalemate in chemotherapy of gastrointestinal cancer may be breaking. Substantial improvements in frequency of tumor regression have been recorded for gastric carcinoma with combinations of 5-FU and BCNU, 5-FU and methyl CCNU, and 5-FU, Mitomycin C, and cytosine arabinoside; for colorectal carcinoma, with the combination of 5-FU, methyl CCNU, and vincristine; and for carcinoid tumors and islet cell carcinomas, with the combination of 5-FU and Streptozotocin. There are also suggestion that such combination chemotherapy with response rates in the 30 to 50% range may produce increased survival when compared to the untreated patient and patients treated with single-drug regimens. While the accomplishments of chemotherapy for the gastrointestinal cancer patient remain less than spectacular there is nevertheless realistic hope that a respectable contribution can now be made to multidisciplinary efforts applied at a stage of disease with minimal tumor burden.
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PMID:Clinical management of advanced gastrointestinal cancer. 16 61

A 45-year-old man with hepatocellular carcinoma who developed intravascular coagulation following complete tumor regression by chemotherapy is described. After 2 doses of 10 mg of Mitomycin C given into the hepatic artery at the time of selective angiography, and 16 intravenous doses of 5-fluorouracil and Mitomycin C, 2 doses per week, subjective symptoms and hepatomegaly disappeared. Alpha-fetoprotein became negative and a remarkable change in tumor size and vasculature was noted in the arteriogram. Three months after chemotherapy, the patient developed thrombocytopenia, intravascular hemolysis, and acute renal failure. Autopsy disclosed a 8 X 7 X 5 cm solitary, encapsulated hepatocellular carcinoma in the right lobe. The tumor was surrounded by a thick capsule and completely necrotized. Neither intrahepatic invasion nor extrahepatic metastasis was observed. In the kidney, generalized fibrin thrombi were seen in the afferent arterioles of glomeruli as accounted for by intravascular coagulation.
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PMID:Complete necrotization of hepatocellular carcinoma by chemotherapy and subsequent intravascular coagulation: a case report. 20 57

An in vivo model is described for assessing the antitumor activity of chemotherapeutic agents. Tumors derived from human colon carcinoma cell lines injected into antithymocyte serum (ATS) immunosuppressed mice were used. In this system, both antitumor effects and host toxicity can be quantitated, permitting calculation of a Therapeutic Index. Compared with other xenograft models, the present system is simple, experiments are completed in less than 2 weeks, and the use of cultured cell lines allows in vitro studies to be performed. The in vitro sensitivities of one colon cell line to 22 chemotherapeutic agents and of four cell lines to three agents is reported. Four drugs used in treating colon cancer (Mitomycin C, 5-FU, BCNU, and methyl-CCNU) show antitumor activity in vivo in this system. Each has a low therapeutic index. Further work with this model is indicated, with the goal of finding new drugs with high Therapeutic Indices.
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PMID:Chemotherapy of cell-line-derived human colon carcinomas in mice immunosuppressed with antithymocyte serum. 30 40

Specific immunological and hematopoietic functions were studied during treatment with antineoplastic agents in mice bearing syngeneic lymphoid tumors: 70Z/2, a B-cell lymphoma of C57BL X DBA/2 F1 (hereafter called (BD2F1) mice; EL4, a T-cell lymphoma of C57BL/6 mice; or J774, a macrophage tumor of BALB/c mice. Both B- and T-lymphocyte function (antibody-forming cells and cell-mediated lymphocyte lympholysis toward alloantigens) were suppressed in spleen cells of mice bearing these tumors. Other hematopoietic functions (granulocyte, macrophage, and megakaryocyte progenitor cells) were variably influenced by growth of these lymphoid tumors. J774 enhanced, but 70Z/2 suppressed, megakaryocyte progenitor cells. J774 and 70Z/2 increased levels of granulocyte-macrophage progenitor cells. EL4, the T-cell lymphoma, did not influence either cell type. Significant variation in strain sensitivity to drug toxicity and drug effectiveness in different tumor-host systems was observed. Increased median survival time with reversal of tumor-induced immune dysfunction, without toxicity to hematopoietic progenitor cells, was realized in two tumor-host-drug combinations. Polyinosinic-polycytidylic acid was effective against J774, while actinomycin D was active against 70Z/2. Mitomycin C effectively reduced tumor load, as evidenced by loss of splenic tumor colony-forming cells for all three tumors. This agent prolonged survival and concomitantly restored immunological responsiveness in hosts immunosuppressed by growth of 70Z/2 or J774. Paralleling tumor reduction with mitomycin C therapy, the splenic hematopoietic progenitor and colony-forming B-cells were reduced in tumor-bearing and tumor-free mice, thus compromising its therapeutic effectiveness. 1-beta-D-Arabinofuranosylcytosine reduced tumor load with marginal toxicity toward hematopoietic progenitor and colony-forming B-cells. However, immune responsiveness was only partially restored, and median survival was not increased. The results presented show the diversity of therapeutic drug effectiveness in increasing mean survival time and influencing other life-sustaining parameters (immunological and hematopoietic functions).
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PMID:Matching of chemotherapy to mouse strain and lymphoid tumor type to prevent tumor-induced suppression of specific T- and B-cell functions. 31 69

The antitumor activity of hot-water extract of delipidated BCG was investigated in mice inoculated with Sarcoma-180 cells and Ehrlich carcinoma cells, respectively. The hot-water extract was found to be effective when administered after and ineffective when administered before the inoculation of tumor cells. When this extract was given with anticancer drugs, such as Mitomycin C and cyclophosphamide, a combined effect was obtained in the treatment of Sarcoma-180 and of Ehrlich carcinoma.
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PMID:Antitumor activity of hot-water extract from delipidated BCG. 35 96


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