摘要:

AbstractThe effects of dietary lipid level, degree of saturation, and antioxidant supplements on ultraviolet‐light (UV) carcinogenesis were studied in female albino hairless mice. Twelve groups, of 42 animals each received a restricted, semipurified, isocaloric diet containing 4%, 12%, or 12% (60% hydrogenated) corn oil with or without antioxidants (2%, w/w). A regimen of escalating UV irradiation was employed until a cumulative dose of 142 J/cm2had been delivered. Tumor development time in 50% of the population (TDT50) was derived from a cumulative distribution of time to tumor formation, which was estimated for all groups. Although there were no significant differences in TDT50s between animals receiving low and high unsaturated lipid dietary regimens, animals receiving hydrogenated corn oil demonstrated a significantly (p<0.01) greater TDT50 and fewer tumors per animal than those receiving either level of unsaturated corn oil. Antioxidants had no effect on TDT50s within any of the dietary groups. However, greater tumor multiplicity was observed in groups receiving unsaturated lipid and antioxidants.These data demonstrate that the degree of dietary lipid saturation modifies the carcinogenic response to UV and suggest that dietary lipid may modify the previously reported inhibitory effect of antioxidants on UV carcinogenesis. It may be concluded that adherence to dietary standards is as important as other experimental parameters when comparisons of UV effects are involved.

ISSN:0163-5581    

DOI:10.1080/01635588309513780

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

摘要:

AbstractOne of the major concerns regarding case‐control studies of diet and cancer is that dietary measures based on current habits may not accurately reflect dietary intake from the time period of cancer initiation and early promotion in the more distant past. Thus, the extent to which current diet correlates with past diet and the reliability of retrospective estimates of past diet are important questions for researchers investigating dietary factors in cancer causation. For these reasons, we conducted this study of the reliability of dietary history as recalled from the distant past. Individuals (N= 175) who completed dietary interviews between the years 1957 and 1965 were reinterviewed in 1982. Subjects were asked to report the usual frequency of intake of selected food items, both at the time of their original interview in the 1957–1965 era as well as at the current time. Dietary histories as recalled from the distant past more closely agreed with those originally recorded than did current diets. The diets as recalled from the distant past appeared to be biased, however, by current dietary habits. The implications of these findings for diet and cancer research are discussed.

ISSN:0163-5581    

DOI:10.1080/01635588309513781

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

摘要:

AbstractThe colon carcinogen 1,2‐dimethylhydrazine (DMH) was cultured with rat colon epithelial cells to determine if these cells have the ability to metabolize DMH. Colon epithelial cells isolated from conventional and germfree Sprague‐Dawley rats were incubated in CMRL 1066 supplemented medium containing14C‐DMH. Cells from both groups of rats metabolized DMH to gaseous metabolites, to metabolites in the medium that were putatively identified as azoxymethane and methylazoxymethanol, and to products that bound to DNA. Cells from germfree rats metabolized DMH at an equal or greater rate than cells from conventional rats for the criteria examined. This report demonstrates that rat colon epithelial cells can metabolize DMH without previous metabolism by other tissues or colon bacteria.

ISSN:0163-5581    

DOI:10.1080/01635588309513782

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

摘要:

AbstractThe mutagenic activity of betel quid and its ingredients was determined usingSalmonella typhimuriumtester strains TA 100, TA 1535, TA 98, and TA 1538, both in the presence and absence of S9 mixture. Aqueous extracts of betel quid (BQ), betel quid with tobacco (BQT), and betel nut (BN) were mutagenic in strain TA 100. Aqueous extract of betel leaf (BL) was not mutagenic in any of the four strains. Arecoline and arecaidine, which are major alkaloids present in BN, were mutagenic in all four tester strains.Tumorigenicity studies in Swiss mice given the above constituents showed that BN and BQ induced lung tumors (47% and 26%, respectively). However, when BN was fed with BL, tumorigenicity was lowered to 38%. BL alone was not tumorigenic. Thus, the mutagenicity of betel quid and its ingredients is correlated with tumorigenicity.

ISSN:0163-5581    

DOI:10.1080/01635588309513783

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

ISSN:0163-5581    

DOI:10.1080/01635588309513784

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

摘要:

AbstractBoth the provitaminβ‐carotene and natural vitamin A and its derivatives (the retinoids) are being proposed as potential chemopreventive agents. The biochemistry and pharmacology of vitamin A suggest a number of mechanisms whereby carcinogenesis can be affected. Epidemiologic studies have consistently demonstrated an increased relative risk of cancer for people with low vitamin A intake or low‐to‐normal serum retinol values. Chemoprevention trials in humans are only now beginning. In the interim, daily consumption of vitamin‐A‐containing foods may be a‘'prescription'’worth folio wing.

ISSN:0163-5581    

DOI:10.1080/01635588309513785

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

ISSN:0163-5581    

DOI:10.1080/01635588309513786

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

ISSN:0163-5581    

DOI:10.1080/01635588309513779

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor