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

Mammary tumor virus (MTV) infection has been shown to be associated with a diminished hypersensitive reaction to methylated bovine serum albumin. Since methylated bovine serum albumin-induced hypersensitivity appears to be a mixed [humoral versus cell-mediated immunity (CMI)] reaction, the deficit in reactivity could be caused by, among other things, a direct depression of CMI or an increase in a humoral, blocking component. Assay of oxazolone-induced contact sensitivity and phytohemagglutinin-induced lymphocyte stimulation revealed normal or greater than normal CMI in MTV-positive animals. Treatment of MTV-positive and -negative animals with a regimen of cytosine arabinoside designed to inhibit only humoral immunity and leave CMI intact, corrected the deficit in methylated bovine serum albumin reactivity in MTV-positive mice. Thus, it is suggested that MTV infection may facilitate the production of interfering or blocking humoral immunity.
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PMID:Correction of a murine mammary tumor virus-associated immunological depression by selective immunosuppression with cytosine arabinoside. 16 63

The hypothesis that selective action of cyclophosphamide, compared to other nitrogen mustards, is due to a balance between enzymatic formation of inactive metabolites and chemical formation of the alkylating product was studied in view of previous observation in our laboratory. Metabolite analysis, inhibition of growth of tumor cells in culture, and kinetic analysis of relevant enzyme activities were used in this investigation. The effect of tissue-soluble enzyme fractions on biochemically prepared aldophosphamide, aldophosphamide analogs, and phosphoramide mustard showed: (a) a range of deactivation abilities with aldophosphamide (liver greater than kidney greater than intestinal mucosa greater than tumor greater than spleen = bovine serum albumin solution); (b) the formation of different amounts of carboxyphosphamide from aldophosphamide; and (c) only comparatively small reductions in the toxicity of phosphoramide mustard and of 4-hydroxy-4methylcyclophosphamide. Correlations were found between NAD+-dependent aldehyde dehydrogenase activity and the deactivation ability of tissue-soluble enzyme fractions. Blockage (by C4 substitution) or inhibition (by disulfiram) of secondary oxidation of aldophosphamide, mediated by aldehyde dehydrogenase, resulted in diminished deactivation ability in vitro and reduced selectivity in vivo.
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PMID:Studies on the selective action of cyclophosphamide (NSC-26271): Inactivation of the hydroxylated metabolite by tissue-soluble enzymes. 17 12

In this investigation, prolactin receptor sites were localized by autoradiography in 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumors from rats. Tumors were removed when they reached the size of 2 X 4 cm and sliced to a thickness of .5 mm. Sections cut from the slices were incubated for 3 hours in medium 199 (1% bovine serum albumin, 5 mM CaC12, 5mM HEPES buffer) at pH 7.4 and 400,000 counts/minute of iodine-125-ovine prolactin in the presence or absence of 1 mcg of unlabeled prolactin. After further preparation and storage for 4 months in a light-tight box slides were developed, fixed and stained and then photographed. All tumors were labeled by iodine-125-ovine prolactin. Prolactin receptors were associated with only half the total cells. Specific prolactin binding was confined to tumor cells and nonspecific binding was present in alveolar spaces and connective tissue. In some tumors prolactin recepotrs were found in all tummor cells, whereas in other tumors half of the cells did not contain any receptors, or very few. Reproductions of autoradiographs illustrate findings. Results suggest that variations in receptor content of the tumors may be caused by 2 distinct populations of cells. 1 type contains many receptors and the other very fewreceptor sites, or none at all.
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PMID:Autoradiographic localization of prolactin receptors in 7,12-dimethylbnez[a]anthracene-induced rat mammary carcinoma. 19 27

Discontinuous bovine serum albumin gradients were used to fractionate peripheral blood leukocytes from bovine leukemia virus (BLV)-free and BLV-infected cows. The release of infectious BLV and spontaneous incorporation of [3H]thymidine were not properties of density gradient-fractionated leukocytes from a BLV-free cow. When leukocytes from BLV-infected cattle were fractionated, B lymphocytes which spontaneously incorporated [3H]thymidine could be separated as a distinct subpopulation from B lymphocytes which replicated infectious BLV. Density gradient fractionation of leukocytes from a cow with lymphosarcoma is also reported. A fall in lymphocyte count at the time of tumor development is attributed to the loss of B lymphocytes which spontaneously incorporate [3H]thymidine.
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PMID:Properties of density gradient-fractionated peripheral blood leukocytes from cattle infected with bovine leukemia virus. 19 12

Sendai virus, one of the most prevalent of the murine viruses, was studied in regard to its capability to alter various functions of rats given a second, unrelated antigenic challenge. Rats given a single foot-pad injection of Freund's complete adjuvant (FCA) had an 85% incidence of adjuvant arthritis. The adjuvant disease was significantly less severe (P less than 0.01) in those rats given 0.05 ml of 10(5.5) median egg infective doses of egg-propagated Sendai virus intranasally 7 days before injection of adjuvant. Rats given Sendai virus concurrently with the FCA, or any time after FCA was injected, did not have a lessened severity of the arthritic reaction, as compared with that in control animals. Sendai virus infection had no detectable effect on median tumor dose requirement for Walker carcinosarcoma cells in rats or on the antibody response to bovine serum albumin.
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PMID:Studies on adjuvant-induced arthritis, tumor transplantability, and serologic response to bovine serum albumin in Sendai virus-infected rats. 20 34

Antigen and tumor incidences in BALB/c and C57BL mice after living as weanlings for 5 weeks in cages with mouse mammary tumor virus-infected females were compared with control BALB/c and C57BL mice living in the same laboratory. All mice were bred continuously, and third-lactation milks were tested for mouse mammary tumor virus antigen by Ouchterlony microimmunodiffusion test. Mammary tumor incidences in the cagemates were not significantly different from those in the controls, although the antigen incidences were significantly greater. However, phosphate-buffered salt solution (0.02 M phosphate, pH 7.4; 0.15 M NaCl; and 0.1% bovine serum albumin) and sham-inoculated mice also had elevated antigen incidences. Repeat tests of milks at the fourth or fifth lactations indicated that more than 50% of those positive at the third became negative at later lactations.
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PMID:Observations on the question of horizontal transmission of mouse mammary tumor virus. 20 68

Cytotoxic effector lymphocytes were induced in cultures of mouse spleen or lymph node cells by lymphocytosis promoting factor (LPF). The LPF-activated cytotoxic cells: (a) were not generated unless proliferation occurred; (b) sedimented in the lighter density fraction of a bovine serum albumin gradient; (c) were large, blast-like cells; and (d) were lysed by Thy-1.2 antiserum plus complement and, therefore, were T cells. Neither LPF alone nor supernates from stimulated cultures were cytotoxic. Unlike the situation with concanavalin A and phytohemagglutinin P, LPF-stimulated cytotoxic effector lymphocytes required no further addition of mitogen for maximal cytotoxicity. The effector cells displayed specificity, destroying only allogeneic but not syngeneic normal cells; in the case of tumor cells, both allogeneic and syngeneic cells werelysed in the absence of added mitogen. The reason for differentiated cytotoxicity toward syngeneic tumor and normal cells is not clear but may have some relevance to in vivo tumor rejection initiated by Bordetella pertussis.
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PMID:The in vitro effects of Bordetella pertussis lymphocytosis-promoting factor on murine lymphocytes. IV. Generation, characterization, and specificity of cytotoxic lymphocytes. 22 13

An improved basal medium is presented that required only minimal supplementation with dialyzed fetal bovine serum or bovine serum albumin and fetuin to be comparable to Ham's F-10, which requires 15% horse serum (HS) and 2.5% fetal bovine serum (FBS) for the growth and function of Y-1, mouse adrenal cortex tumor, cells. Cell monolayers maintained for up to 2 weeks without any protein supplementation have retained their steroid response to ACTH. The medium differs from Ham's F-10 in its buffer composition and higher calcium-ion concentration. This medium should be a useful adjunct to studies pertaining to steroid and lipid intermediary metabolism, the retention of a specialized physiological function in a chemically defined medium, and the mechanism of hormonal response.
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PMID:Improved basal medium for Y-1 mouse adrenal cortex tumor cells in culture. I. Dependence of growth and steroid response on calcium ion concentration. 23 59

Hydrocortisone at physiological concentrations reversibly inhibits DNA synthesis in ST1 cells (a line of mouse fibroblasts possessing 40 chromosomes and derived from Swiss 3T3 cells). This inhibitory activity is a property of glucocorticoids, but the beta-OH of C-11 of glucocorticoids is not essential for the inhibition. The steroid hormone restores to ST1 cells dependency on serum, density, and anchorage for growth. When injected into nude mice, ST1 cells generated malignant invasive fibrosarcoma. Injections of dexamethasone into tumor-bearing animals blocked tumor growth. The steroid hormone seems to induce a reversible transition between a transformed and a "normal" phenotype. ST1 cells treated or untreated with hydrocotisone are not responsive to fibroblast growth factor, epidermal growth factor, or prostaglandin F2alpha whereas they are responsive to a factor that is a contaminant in bovine serum albumin.
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PMID:Steroid hormones mediate reversible phenotypic transition between transformed and untransformed states in mouse fibroblasts. 27 50

Methotrexate (MTX) covalently bound to bovine serum albumin (MTX-BSA), injected ip (10 mg/kg) once every 4 days for a total of 4 doses, was more effective than an equivalent dose of free MTX in reducing the number of metastases observed in female (C57BL/6 X DBA/2)F1 mice bearing the sc implanted Lewis lung carcinoma. Treatment with the high-molecular-weight derivative of MTX in addition caused a decreased rate of growth of the primary tumor and a modest increase in the life-span of the tumor-bearing animal. When tumor-bearing mice were killed after receiving injections of [3H]MTX or [3H]MTX-BSA, no difference in the amount of drug was found at the tumor site after 1 hour; however, after 8 or 24 hours, twice as much radioactivity was found in the tumors of mice treated with carrier-bound drug. Analysis of this radioactivity indicated a ratio of 60--80% carrier-bound to 20--40% free MTX.
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PMID:Control of solid tumor metastases with a high-molecular-weight derivative of methotrexate. 28 78


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