摘要:

AbstractWe studied the effects that dietary fat has on the capacity of preparations of rat small intestinal mucosal cells to metabolize benzo[a]pyrene (BP) in vitro and on the composition of fatty acids in the endoplasmic reticulum of the intestinal mucosa. When rats were fed diets containing different types of fat, there were significant changes in the incorporation of fatty acids into the endoplasmic reticulum of the mucosal cells of the small intestine: the proportions of polyunsaturated fatty acids in the endoplasmic reticulum reflected the amounts of these fatty acids in the dietary fat. The rate of BP oxidation in the intestinal mucosa was dependent on the amount and composition of the dietary fat, but the range and proportions of the metabolites produced were not affected. Dietary C18:2was particularly important in elevating the rate of BP oxidation, but dietary C20:5and C22:6also effectively increased the rate of BP oxidation. The rate of BP oxidation in the small intestine of rats fed different diets was positively correlated with the proportion of polyunsaturated fatty acids in the endoplasmic reticulum of the mucosal cells.

ISSN:0163-5581    

DOI:10.1080/01635588609513889

出版商:Taylor&Francis Group    

年代:1986

数据来源: Taylor

摘要:

AbstractThe effect of individual vitamins and minerals on esophageal carcinogenesis was assessed by supplementing a diet (based on corn) that was marginally deficient in many micronutrients. The test diets were fed to weanling inbred BD IX rats for 45 days; they were then given five subcutaneous doses (3 mg/kg body wt)N‐nitrosomethylbenzylamine (MBN) over two and one‐half weeks. The diets were continued until termination: 150 days later; at that time all rats were still clinically normal. Marked reductions in the number of tumors and tumor‐bearing rats were recorded in groups of rats given supplements of riboflavin, nicotinic acid, zinc, magnesium, selenium, and molybdenum. Various combinations of nutrients did not distinctly reduce the tumor yield further; however, tissue analyses suggest that individual supplements could enhance the status of other marginally deficient nutrients. When the experiment was repeated, but was varied by commencing the supplements only well after the cessation of MBN exposure, inhibitory effects on tumorigenesis were still exerted by most nutrients. We emphasized that these nutritional effects along with the epidemiological evidence in humans are relevant to early prevention; also, the treatment of premalignant esophageal changes by high doses of these nutrients may be unwise. The merits of food supplementation schemes are discussed.

ISSN:0163-5581    

DOI:10.1080/01635588609513890

出版商:Taylor&Francis Group    

年代:1986

数据来源: Taylor

摘要:

AbstractAll‐trans retinoic acid (10−5M) added at seeding reduces the growth rate and saturation density of normal human embryonic lung fibrolasts of two lines (WI‐38 and IMR‐90) and similarly inhibits growth of SV40‐transformed WI‐38 cells (VAI3A). The growth inhibitory effects of retinoic acid do not show serum dependency, and the viability of treated cells is 95–99% of controls. Old populations of WI‐38 cells (cells at high population doubling levels) are more sensitive to the effects of retinoic acid than are young populations (cells at low population doubling levels), and population life span is reduced by continuous exposure to retinoic acid. When retinoic acid is combined with the gluococorticoid hydrocortisone, inhibition of VAI3A cell growth is increased, whereas the retinoic acid‐induced inhibition of normal cells is decreased. VA13A cells treated with retinoic acid alone, or in combination with hydrocortisone, exhibit a reversion to a more elongated, fibroblast‐like appearance. This paper discusses the clinical implications of the relationship between retinoic acid and hydrocortisone.

ISSN:0163-5581    

DOI:10.1080/01635588609513891

出版商:Taylor&Francis Group    

年代:1986

数据来源: Taylor

摘要:

AbstractAmong urban blacks in Johannesburg, South Africa, a measure of westernization of diet has occurred. Yet, the frequencies of most noninfective bowel diseases not only are low but also appear to have scarcely increased. To assess more adequately the current dietary pattern, a survey was undertaken. Results indicated a habitually low‐fat intake, which supplied a mean of 24% of energy but also greatly decreased fiber intake (now about 14 g daily). Possibly, a meaningful rise in the incidence of bowel diseases requires, among other things, simultaneous rise in fat intake; alternatively, there are factors yet unknown in the dietary context of urban blacks (perhaps operating in their bowels) that are inhibiting rises in the diseases mentioned.

ISSN:0163-5581    

DOI:10.1080/01635588609513892

出版商:Taylor&Francis Group    

年代:1986

数据来源: Taylor

摘要:

AbstractYoung, virgin female Fischer 344 rats bearing the 13762 transplantable mammary tumor were fed diets containing either 5% (low‐fat group) or 23% (high‐fat group) corn oil for five weeks before and six weeks after tumor implantation. Animals in the two diet groups gained weight at comparable rates throughout the experiment. There was no significant difference between the low‐fat and high‐fat groups with respect to average tumor diameter measured twice per week for six weeks. At the time of death (6 weeks after tumor implantation), the lungs of all rats in both diet groups contained some metastatic tumor deposits; the volume of the metastases in the lungs varied widely in both groups. Numbers of metastases to regional lymph nodes and kidneys appeared unaffected by the fat content of the diet. Thus, both growth of the 13762 mammary tumor itself and metastatic spread from the tumor were comparable whether the young rats were fed a high‐fat or a low‐fat diet.

ISSN:0163-5581    

DOI:10.1080/01635588609513893

出版商:Taylor&Francis Group    

年代:1986

数据来源: Taylor

摘要:

AbstractTurmeric, which is one of the commonly used spices in Indian cooking, was tested for mutagenicity using the Ames test. The alcoholic extract of fresh or dried turmeric, its principal components, and pyrolyzed turmeric powder and curcumin were tested for mutagenicity in Salmonella typhimurium strains with and without metabolic activation. None of these were mutagenic in all the tester strains. Chilies (which are used with turmeric powder) and their principal alkaloid capsaicin were mutagenic in the TA 98 with S9 mixture. We tested curcumin, which is the principal component of turmeric, for its antimutagenic effect. It showed dose‐dependent decreases in mutagenicity of chili extract and capsaicin. Also, we compared the antimutagenicity of curcumin with other known antioxidants, including BHA, vitamins E and C, and vegetable oils. These all showed dose‐dependent decreases in mutagenicity of chili extract and capsaicin. These studies show that although there are few mutagenic principles in Indian food, there is still quite a large number of antimutagenic principles in the Indian diet that will modulate the activity of environmental mutagens.

ISSN:0163-5581    

DOI:10.1080/01635588609513894

出版商:Taylor&Francis Group    

年代:1986

数据来源: Taylor

摘要:

AbstractAllyl methyl trisulfide (AMT), a constituent of garlic oil, was studied for its effects on glutathione S‐transferase (GST) activity and on benzo[a]pyrene (BP)‐induced neoplasia of the forestomach and lungs of female A/J mice. AMT induced increased GST activity in the forestomach, small bowel mucosa, liver, and lung. The forestomach and small bowel mucosa responded to a single low dose of AMT (3.0μmol) given by oral intubation, whereas liver and lung were less reactive. A dose schedule of two administrations of 15μmol AMT given 48 hours apart gave close‐to‐maximum induction in all four tissues and was chosen for investigation of its inhibitory effects. With this dose schedule, AMT produced an inhibition of BP‐induced neoptasia of the forestomach as shown by a greater than 70% reduction in the number of tumors found at the completion of the experiment. Inhibition of pulmonary neoplasia did not occur. AMT is a member of a new class of naturally occurring chemicals that have the capacity to inhibit chemical carcinogenesis.

ISSN:0163-5581    

DOI:10.1080/01635588609513895

出版商:Taylor&Francis Group    

年代:1986

数据来源: Taylor

摘要:

AbstractCertain plants contain structures consisting of biogenic silica. This form of silica has been implicated as a causative agent in the high esophageal cancer areas of southern Africa, northeast Iran, and northern China. A spicule shape of biogenic silica is known to act as a tumor promoter in the mouse skin model system. The observation that fine biogenic silica fibers are found in leaves of sugarcane may pose a hazard for cane workers; also, the discovery that bracken contains silica fibers could have implications for browsing cattle. This paper reviews and discusses the involvement of biogenic silica in disease.

ISSN:0163-5581    

DOI:10.1080/01635588609513896

出版商:Taylor&Francis Group    

年代:1986

数据来源: Taylor

ISSN:0163-5581    

DOI:10.1080/01635588609513888

出版商:Taylor&Francis Group    

年代:1986

数据来源: Taylor