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

A comparative study has been performed on the relationship between vitamin E and immunofunction in normal and malignant condition in human and murine systems. Further, the effects of supplemental vitamin E on tumor take, host survival and tumor growth have been studied in a transplantable lymphoma in mice. Vitamin E was assayed in serum samples from normal subjects and from patients with leukemia and lymphoma by high performance liquid chromatography (HPLC). The murine group included Dalton's ascitic lymphoma (DL), Schwartz lymphoblastic leukemia (SVL) and Moloney lymphoblastic leukemia (MVL). Serum vitamin E was found to be lower than that of the normal controls in all cases of leukemia and lymphoma both in human and animal system. The levels of immunoglobulins (IgG and IgM) were found to be higher in mice with leukemia and lymphoma. Supplementary vitamin E administered at the initial phase of development of murine lymphomas reduced the rate of tumor growth, improved host survival and elevated serum vitamin E level. Vitamin E supplementation also activated specific mitogen induced blastogenesis of peripheral blood lymphocytes (PBL) and elevated serum IgG level. IgM remained unaltered and macrophage activity did not seem to be affected. The present findings indicated a low status of vitamin E in tumor bearing host and a beneficial effect of supplemental vitamin E on the host which was mediated by the host immune system.
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PMID:Vitamin E--its status and role in leukemia and lymphoma. 827 50

The dorsal skins of 6-8 week old female SENCAR mice were initiated with a single application of 10 nmol of 7,12-dimethylbenz[a]anthracene (DMBA) and subsequently promoted twice/week with topical applications of vitamin E (dl-alpha-tocopherol, 80 mumol/treatment). Vitamin E from two separate commercial suppliers was tested. For comparison, a group of similar mice, also initiated with DMBA, was promoted twice/week with the known tumor promoter 12-O-tetradecanoylphorbol-13- acetate (TPA, 2 micrograms/treatment). Papillomas appeared 39 and 50 days respectively after promotion began with vitamin E from the two different sources, as compared with 32 days in the group receiving TPA promoted. Hundred per cent of TPA-promoted animals and 92-96% of the vitamin E-promoted mice developed tumors. A maximum of 15 papillomas/animal appeared in the TPA-promoted mice. The two vitamin E preparations were somewhat less effective than TPA and showed different relative potencies, producing about seven and 12 papillomas per animal respectively. Unlike TPA, vitamin E showed very little ability to produce an inflammatory response in skin. To test whether initiated cells that did not appear as papillomas after vitamin E promotion were still viable, and had proceeded past stage I of promotion (conversion), the group that developed 12 papillomas/animal from vitamin E promotion was further promoted with mezerein, a stage II promoter. In this group, the papilloma frequency then increased to approximately 17/animal. The animals were followed over the course of their lifespan and monitored for skin carcinomas. In the TPA-promoted group 64% of the mice developed carcinomas, while the two vitamin E-promoted groups showed 48 and 60% incidence respectively. These results indicate that topically applied vitamin E acts as a complete tumor promoter in DMBA-initiated mouse skin, with an efficiency approaching that of TPA. Since vitamin E is a powerful antioxidant, they also suggest that reduction of cellular oxidant levels may trigger the tumor promotional process, and it may therefore be prudent to avoid repetitive or prolonged topical exposure of human skin to antioxidants like vitamin E.
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PMID:Vitamin E is a complete tumor promoter in mouse skin. 847 30

A significant change of vitamin E and malondialdehyde plasma concentrations was reported in breast cancer patients. This change was unexpected because vitamin E was higher and malondialdehyde lower in cases than in controls, and the difference was more significant in young rather than older women. The first aim of this study was to determine whether these changes were associated only with breast cancer, or with hormone-related cancers, and/or cancers associated with nutritional risk factors or with all types of cancers. Measurements were performed before therapy on 269 hospital-based controls and on 146 patients with various carcinomas. Vitamin E:total cholesterol increased and malondialdehyde plasma concentration decreased with tumor size and progression, without relation to the site. The second aim was to understand the difference in the change observed between young and old breast cancer patients. These analytes were measured in 365 breast cancer patients according to three prognosis factors: pathology, tumor size and estrogen receptors. Vitamin E:total cholesterol significantly decreased with estrogen receptor amount. Malondialdehyde plasma concentration decreased with severity of pathology and tumor size. Together, these data support the association of an altered oxidant-antioxidant profile in cancer patients with tumor growth and progression.
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PMID:Oxidant-antioxidant status alterations in cancer patients: relationship to tumor progression. 864 57

The level of vitamin E was measured in 31 renal carcinomas and unaffected renal cortex taken as control. Two groups were formed in respect to cell composition of the carcinoma: 14 tumors composed of clear cells; 17 tumors composed of other types cells. Vitamin E concentrations and total lipids in the tumor tissue were elevated. Despite a significant positive correlation between levels of vitamin E and lipids in cancer tissue, high content of lipids is not the main reason of vitamin E accumulation. Concentration of vitamin A measured in 17 carcinomas was similar to control as per 1 mg of tissue lipids. Blood levels of vitamin E and total lipids in 12 patients with renal cell carcinoma were significantly higher than in healthy subjects and returned to normal after nephrectomy.
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PMID:[Fat-soluble vitamins E and A in the tumor tissue and in the blood of patients with renal-cell cancer]. 903 2

We previously reported on a paradoxical oxidant-antioxidant status in breast cancer patients, more so in pre-menopausal than menopausal women. In this study, measurements were performed on 146 patients with various carcinomas. Vitamin E/total cholesterol increased and plasma malondialdehyde decreased with tumor size and progression. To investigate the difference between young pre-menopausal and aged menopausal breast cancer patients, the same measurements were performed in 365 breast cancer patients according to pathology, tumor size and estrogen receptors. The oxidant-antioxidant status varied with these prognosis factors in the same pattern, and was more pronounced in young than aged women.
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PMID:Tumor progression and oxidant-antioxidant status. 910 94

Vitamin E (tocopherol) acts in various organisms as the main free radical scavenger. This capacity, which is enhanced by the synergetic effect of vitamin C and carotenes, points to a possible application as anti-tumor agent in chemotherapy. There are several isomeric forms, namely alpha-, beta-, gamma-, and delta-tocopherol, having different antioxidative abilities, with alpha-tocopherol being the most biologically active. Using methanol as eluent and a C30 stationary phase, we achieved complete separation of alpha-, beta-, gamma-, and delta-tocopherol and alpha-tocopherol acetate by RP-HPLC within 14 min. Detection was performed by UV and 1H NMR spectroscopy. The advantage of NMR is the possibility of structural identification of chromatographic peaks. Also, coeluting peaks are easily recognized. The enhanced shape recognition of the C30 phase has been attributed to the high order of the alkyl chains of the stationary phase. This has, so far, been proven by solid-state NMR spectroscopy. We now introduce the technique of 13C MAS NMR spectroscopy of suspended stationary phases. The resulting NMR spectra reveal that, in the presence of weak eluents, like methanol, the overall high order of the C30 chains is slightly altered, whereas in stronger eluents, like MTBE, the alkyl chains possess a higher mobility.
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PMID:Shape selectivity of C30 phases for RP-HPLC separation of tocopherol isomers and correlation with MAS NMR data from suspended stationary phases. 943 66

Polyunsaturated fatty acids (PUFA) have a selective cytotoxic/cytostatic effect on a number of tumor cell lines in culture. Although this process may be enhanced by the addition of iron there is a minimum level of PUFA necessary for potentiation of cell death. Vitamin E blocks PUFA cytotoxicity when added up to 5 days after fatty acid administration. Levels of thio-barbiturate reactive material (TBARM) in the medium rise in parallel with cell death. However, they are not affected by small alterations in temperature or oxygen tension. Incubating cells with PUFA causes marked alterations in the fatty acid patterns of both neutral and phospholipid fractions. Membrane fluidity is increased and the activity of membrane-bound receptors may be influenced directly or through the actions of eicosanoids derived from the exogenous fatty acid. PUFA may be an effective way of influencing tumor growth and a safe approach for the management of human cancer.
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PMID:Mechanisms of the selective cytotoxic actions of certain essential fatty acids. 954 2

The effect of a long-lasting loading with alpha-tocopherol on the development of dimethylnitrosamine-induced kidney tumors was investigated in 55 non-bred white male rats. The carcinogen was repeatedly introduced into the stomach by means of a gastric tube. Starting 24 days after the last administration of the carcinogen the alpha-tocopherol loading began and lasted up to the end of the experiment. 21 rats were loaded with vitamin E introduced into the stomach, 5 times a week at a dose of 70 mg/kg body weight. 17 rats received sunflower seed oil--the vitamin E solvent; other 17 rats received only standard ration. The control group (20 rats) were not treated with the carcinogen. One part of these rats received alpha-tocopherol by the above schedule while another part--sunflower oil alone. It was shown that the alpha-tocopherol loading had no effect on the incidence of renal tumors. Nevertheless it enhanced to some extent the rate of their development as well as the incidence of blastomes in other organs. Based on histological examination, tumors developed in kidneys were of epithelial and mesenchymal origins with the mesenchymal tumors occurring more frequently (63-69% of the total). Vitamin E content in tumor tissue of rats, loaded or not loaded with alpha-tocopherol, was much higher than that in intact kidneys of corresponding control animals, suggesting a high tumor tropism of this vitamin. Total lipid concentration of tumor tissue was 1.5 times lower than that of intact kidneys. Histological nature of tumors had no visible effect on their vitamin E and total lipid content.
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PMID:[Accumulation of vitamin E in dimethylnitrosamine-induced kidney tumors in rats with various levels of alpha-tocopherol supplementation]. 963 18

Lung cancer is the leading cause of cancer death in the United States. The persisting grim lung cancer incidence and mortality figures argue powerfully for new approaches such as chemoprevention for controlling this disease. Retinoids are among the most intensively studied cancer chemoprevention agents, including in the lung. Several randomized clinical or translational chemoprevention trials (e.g., of retinoids, beta-carotene, or combined folic acid and vitamin B(12)) have been conducted in lung pre-malignancy. Retinoid studies have produced important data on molecular/cellular markers of lung carcinogenesis, e.g., loss of heterozygosity (LOH) at 3p and 9p and retinoic acid receptor-beta (RAR-beta). Two large randomized trials with a lung cancer endpoint, the Alpha-Tocopherol, Beta-Carotene (ATBC) Prevention Study and the Beta-Carotene and Retinol Efficacy Trial (CARET), found that beta-carotene (+/- retinol) was harmful (in smokers). Recently completed lung-second-primary-tumor-prevention trials include the retinoids retinyl palmitate and 13-cis-retinoic acid (13cRA) and N-acetylcysteine (NAC). Vitamin E and selenium show promise for lung cancer prevention, based on positive secondary/subset analyses of three large-scale, randomized National Cancer Institute (NCI) cancer prevention trials. Future directions of lung cancer chemoprevention include the study of molecular markers of risk and drug activity, molecular targeting study, improved imaging techniques (e.g., molecular imaging) and new drug delivery systems.
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PMID:Lung cancer chemoprevention. 1065 11

Two well-known antioxidative nutrients, vitamin E and selenium, were used in this study to investigate possible inhibitory action against the formation of esophageal adenocarcinoma (EAC) in rats. In this model, carcinogenesis is believed to be driven by oxidative stress. Male Sprague-Dawley rats (8 weeks old) were divided into four groups and received esophagoduodenal anastomosis (EDA) surgery plus iron supplementation (12 mg/kg/week). Vitamin E and selenium were supplemented in the diet in the forms of alpha-tocopheryl acetate (750 IU/kg) and sodium selenate (1.7 mg Se/kg), which were 10 times the regular amounts in the basic AIN93M diet. At 40 weeks after surgery, all the EDA groups had lower body weights than the non-operated control group. Iron nutrition (hemoglobin, total serum iron and transferrin saturation) was normal as a result of iron supplementation after EDA. Vitamin E supplementation maintained the normal plasma level of alpha-tocopherol in EDA rats, but not those of gamma-tocopherol and retinol. Selenium supplementation increased the serum and liver selenium contents of the EDA rats. Histopathological analysis showed that selenium supplementation increased the incidence of EAC and the tumor volume. The selenium level in the tumor is higher than that in the duodenum of the same animal. Vitamin E supplementation, however, inhibited carcinogenesis, especially in the selenium-supplemented group. We believe that vitamin E exerts its effect through its antioxidative properties, and a high dose of inorganic selenium may promote carcinogenesis by enhancing oxidative stress.
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PMID:Effects of vitamin E and selenium supplementation on esophageal adenocarcinogenesis in a surgical model with rats. 1091 Sep 55


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