ISSN:0163-5581    

DOI:10.1080/01635588509513809

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractThis study was designed to determine the effects of four well‐characterized dietary brans on large bowel tumorigenesis induced in mice with 1,2‐dimethylhydrazine (DMH). Eight‐week‐old barrier‐derived male Balb/c mice were fed a semisynthetic diet with 20% bran added (either corn, soybean, soft winter wheat, or hard spring wheat) or a no‐fiber‐added control diet. Half of each group was given DMH (20 mg/kg body weight/week, subcutaneously for 10 weeks) beginning at 11 weeks of age. Surviving mice were killed 40 weeks after the first DMH injection. Tumors were not found in mice not subjected to DMH. In DMH‐treated mice, tumors were found almost exclusively in the distal colon. Tumor incidences were as follows: controls, 11 %; soybean group, 44%; soft winter wheat group, 48%; hard spring wheat group, 58%; and corn group, 72%. Tumors per tumor‐bearing mouse ranged from 1.4 to 1.6, except in the corn group, which had 2.1. A positive correlation was found between percentage of neutral detergent fiber in the brans and tumor incidences but not between the individual components of cellulose, hemicellulose, or lignin. The enhancement of DMH‐induced large bowel tumorigenesis by all four bran types may reflect a species and/or mouse strain effect that is bran‐source related. These data emphasize the importance of using well‐defined bran in all“fiber”; studies.

ISSN:0163-5581    

DOI:10.1080/01635588509513810

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractWeanling rats were fed low‐fat (1 % w/w safflower oil) or high‐fat (1% w/w saf‐flower oil plus 35% w/w beef fat or cocoa butter) diets for 30 days, and the activities of five cecal microbial enzymes were determined. When compared with the low‐fat diet, beef fat significantly increased total cecalβ‐glucuronidase activity, but cocoa butter, with a similar fatty acid composition, did not. Both high‐fat diets significantly decreased total cecal azoreductase,β‐glucosidase, and nitrate reductase activities, but neither significantly affected urease activity. When expressed as specific activities (per 1011bacteria), cocoa butter decreased azoreductase, and beef fat caused increases ofβ‐glucuronidase and urease. Beef fat, but not cocoa butter, significantly reduced cecal bacterial numbers when compared to the low‐fat diet. Both high‐fat diets led to equivalent reductions in the proportion of aerobic bacteria.

ISSN:0163-5581    

DOI:10.1080/01635588509513811

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractThe sulfated polysaccharides degraded carrageenan and dextran sulfate sodium were studied for genotoxicity using DNA repair tests employing cultured rat hepatocytes or intestinal mucosal cells. No evidence of unscheduled DNA synthesis was obtained. In addition, both alone and in combination with the comutagen norharman, these substances were nonmutagenic in the Salmonella microsome/mutagenicity test. These findings suggest that the carcinogenicity of the sulfated polysaccharides may be due to nongenotoxic mechanisms.

ISSN:0163-5581    

DOI:10.1080/01635588509513812

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractForty‐eight young male and female golden hamsters (Mesocricetus auratus) were divided into four groups of 12 animals each. The left buccal pouches of Group 1 and 2 animals were painted 3 times weekly with a 0.5% solution of 7,12‐dimethyl‐benz(a)anthracene (DMBA) in heavy mineral oil for 7 weeks. At the end of this period, the left buccal pouches of Group 2 animals were painted 3 times weekly with vitamin E (DL‐α‐tocopherol, in pure form) for an additional 4 weeks. Group 3 animals were painted with vitamin E only, for 4 weeks. Group 4 animals were untreated controls. Group 2 animals demonstrated a significant delay in tumor formation in comparison with Group 1 animals. Gross observation revealed fewer and smaller tumors in the Group 2 animals; microscopic examination revealed smaller tumors with better cellular differentiation and less invasion. No tumors were observed in Group 3 and Group 4 animals. These observations were similar to those made in previous studies of oral carcinogenesis using systemic vitamin E to delay tumor formation.

ISSN:0163-5581    

DOI:10.1080/01635588509513813

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractSixteen studies of the relationship between lung cancer and vitamin A in humans are critically reviewed: eight dietary studies and eight serum studies. Of the eight dietary studies, only five had case samples large enough to warrant meaningful statistical analysis. Three dietary studies reported a negative association between vitamin A intake and lung cancer after proper adjustment for cigarette smoking and socioeconomic effects; the results suggested that daily consumption of green‐yellow vegetables reduces the risk of lung cancer in all categories of smokers. The reduction in risk was found to be greatest in persons in the higher socioeconomic strata. Four dietary studies suggested that high intake of dietary vitamin A has a protective effect against the development of squamous and small cell carcinoma of the lung in smokers. Three studies revealed a lower risk of lung cancer among persons who consume carrots and milk daily. None of the eight serum studies reviewed had large enough samples of lung cancer cases to allow for meaningful statistical analysis. However, four of the serum studies reported significantly lower serum vitamin A levels in lung cancer cases than in controls. Analysis of the above studies demonstrated shortcomings in each. Future studies should include all of the following factors: more complete vitamin A indices, examination of the histological type of lung cancer, a large enough pool of both male and female patients for statistical analysis, and proper adjustment for the effects of age, sex, smoking, and socio‐economic status.

ISSN:0163-5581    

DOI:10.1080/01635588509513814

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractThis paper is a review of experimental data leading to three main conclusions:1.Food deprivation causes a 2‐to 3‐fold increase in the metabolism of various chemicals in rat liver, such as chloroform and carbon tetrachloride. The lack of carbohydrate rather than the lack of protein or fat accompanying food deprivation is primarily responsible for the increase.2.In contrast to general belief, dietary carbohydrate plays an important role in regulating drug‐metabolizing enzyme activity in the liver: a low‐carbohydrate diet enhances, whereas a high‐carbohydrate diet represses, the hepatic metabolism of a variety of volatile hydrocarbons, irrespective of protein and/or fat content(s).3.Ethanol and carbohydrate are antagonistic in connection with hepatic metabolism: the former increases and the latter decreases it. A decrease (increase) in carbohydrate intake augments (suppresses) the action of ethanol in a dose‐related manner: ethanol consumed with lowered carbohydrate intake results in a more remarkable increase in hepatic metabolism than does ethanol consumed with moderate carbohydrate intake.Further study should be conducted to determine whether the conclusions reached also apply to the metabolism of foreign chemicals other than volatile hydrocarbons.

ISSN:0163-5581    

DOI:10.1080/01635588509513815

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

ISSN:0163-5581    

DOI:10.1080/01635588509513808

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor