摘要:

AbstractLimonin 17‐β‐d‐glucopyranoside, nomilin 17‐β‐d‐glucopyranoside, and nomilinic acid 17‐β‐d‐glucopyranoside, three limonoid glucosides isolated from oranges, were tested for cancer chemopreventive activity. Eighty female Syrian hamsters were divided into four equal groups. The left buccal pouches of the animals in each group were pretreated topically with two applications of water (Group I) or a 3.5% solution of limonin 17‐β‐d‐glucopyranoside (Group II), nomilin 17‐β‐d‐glucopyranoside (Group III), or nomilinic acid 17‐β‐d‐gluco‐pyranoside (Group IV). After this initial treatment, the left buccal pouches of 16 hamsters from each group were painted five times per week. Two or three times per week the pouches were treated with a 0.5% solution of the carcinogen 7,12‐di‐methylbenz[a]anthracene (DMBA) dissolved in mineral oil. On alternate days, the pouches were treated with water (Group I) or a 3.5% solution of limonin 17‐β‐d‐glucopyranoside (Group II), nomilin 17‐β‐d‐glucopyranoside, or nomilinic acid 17‐β‐d‐glucopyranoside. The 16 remaining animals were used as controls. These hamsters were treated five times per week, one day with mineral oil and the next with either water (Group I) or one of the 3.5% solutions of the limonoid glucosides (Groups II‐IV). After 15 weeks (71 applications), the hamsters were killed. Multiple tumors were common in the animals treated with DMBA; however, the animals treated with limonin 17‐β‐d‐glucopyranoside exhibited a 55% decrease in average tumor burden. Further comparisons between Groups I and II showed that this reduction in tumor burden was mainly due to a decrease in tumor mass. The results for Groups III and IV showed that nomilin 17‐β‐d‐glucopyranoside and nomilinic acid 17‐β‐d‐glucopyranoside were ineffective as inhibitors of DMBA‐induced buccal pouch neoplasia.

ISSN:0163-5581    

DOI:10.1080/01635589209514167

出版商:Taylor&Francis Group    

年代:1992

数据来源: Taylor

摘要:

AbstractThe relationship between dietary fat consumption and the incidence of breast cancer, if any, needs to be quantified so that dietary guidelines can be issued for the prevention of breast cancer. Frequently, only two widely different dietary fat levels, often differing in essential fatty acid content, have been compared in animal models. Moreover, the latent period in common animal models for breast cancer is very short and does not reflect the relatively long latent periods in human breast cancer.We describe a study with BALB/c‐MTV mice, a strain with a high average tumor incidence and a latent period of over 60 weeks on average. The mice were fed diets with fat levels ranging from 10% to 40% of energy, in which fat was isocalorically substituted for carbohydrates. The level of linoleic acid in these diets was kept constant at 6.5% of energy. Both the mean tumor incidence and latent periods of the groups fed diets with 10–16% of energy as fat were not significantly different from each other. There were also no differences between these parameters in the groups fed 22–40% of energy as fat. However, the mean incidence and latent period of the groups fed 22% or more of energy as fat was significantly higher than that of the groups fed less fat. We conclude that above about 22% of energy, fat does not influence the incidence and latent period of mammary tumors in BALB/c‐MTV mice.

ISSN:0163-5581    

DOI:10.1080/01635589209514168

出版商:Taylor&Francis Group    

年代:1992

数据来源: Taylor

摘要:

AbstractMany furan‐containing natural products that induce increased activity of the glutathione S‐transferase (GST) enzyme system have been found to inhibit tumorigenesis in laboratory animals. 2‐n‐Heptylfuran (HF) and 2‐n‐butylthiophene (BT), a sulfur analogue of furan, are two of the many furans and thiophenes formed during the roasting process of meat. BT and HF, when administered by gavage at doses that ranged from 11 to 90μmol, induced increased GST activity in various tissues of A/J mice. At 90μmol/dose, BT induced increased GST in the liver, small bowel mucosa, and lung. No increase in enzyme activity was found in the forestomach. HF was an enzyme inducer in the liver, small bowel mucosa, and forestomach but was inactive in the lung. The acid‐soluble sulfhydryl level, a good measure of glutathione contents in tissues, was examined in tissue homogenates from mice treated with BT and HF. BT induced significant increase of GSH in the liver and lung at the higher doses. No change was observed in either the small bowel mucosa or the forestomach. A 50‐μmol dose of HF was found to increase GSH level in all four tissues studied. The inhibition of lung and forestomach tumorigenesis was carried out with A/J mice using benzo[a]pyrene as the carcinogen. BT treatment resulted in a reduction of tumor multiplicity in the lung and forestomach. The tumor incidence in the forestomach was reduced significantly. The potency of HF as inhibitor of carcinogenesis was similar to that of BT in the forestomach of mice. In the lung, HF was found to be ineffective as an inhibitor of pulmonary adenoma formation. These results suggest that furan‐and thiophene‐containing compounds may be effective inhibitors of chemical carcinogenesis.

ISSN:0163-5581    

DOI:10.1080/01635589209514169

出版商:Taylor&Francis Group    

年代:1992

数据来源: Taylor

摘要:

AbstractThe relationship between tea consumption and cancer risk has been analyzed using data from an integrated series of case‐control studies conducted in northern Italy between 1983 and 1990. The dataset included 119 histologically confirmed cancers of the oral cavity and pharynx, 294 of the esophagus, 564 of the stomach, 673 of the colon, 406 of the rectum, 258 of the liver, 41 of the gallbladder, 303 of the pancreas, 149 of the larynx, 2,860 of the breast, 567 of the endometrium, 742 of the ovary, 107 of the prostate, 365 of the bladder, 147 of the kidney, 120 of the thyroid, and a total of 6,147 controls admitted to hospital for acute nonneoplastic conditions unrelated to long‐term dietary modifications. Multivariate relative risks (RR) for tea consumption were derived after allowance for age, sex, area of residence, education, smoking, and coffee consumption. All the estimates for tea consumption were close to unity, the highest values being 1.4 for rectum, gallbladder, and endometrium. There was no association with cancers of the oral cavity (RR = 0.6), esophagus (RR = 1.0), stomach (RR = 1.0), bladder (RR = 0.8), kidney (RR = 1.1), prostate (RR = 0.9), or any other site considered. Although in northern Italy tea was consumed daily by only a limited proportion of the population, this integrated series of studies offers further reassuring evidence on the relationship between tea and cancer risk.

ISSN:0163-5581    

DOI:10.1080/01635589209514170

出版商:Taylor&Francis Group    

年代:1992

数据来源: Taylor

摘要:

AbstractA case‐control study among white men in western New York was conducted from 1975 through 1985 to examine diet and other risk factors for laryngeal cancer. Incident pathologically confirmed cases (250) and age‐and neighborhood‐matched controls (250) were interviewed to determine usual diet and lifetime use of tobacco and alcohol. Cigarettes were strongly associated with risk; pipes and cigars were not. Beer and hard liquor but not wine were associated with increased risk. Dietary fat and carotenoids were related to risk in opposite ways. The upper quartile odds ratio for dietary fat was 2.40 [95% confidence interval 1.26,4.55], and the upper quartile odds ratio for carotenoids was 0.51 (0.26,1.01). There was effect modification by smoking. Carotenoids were most negatively associated with risk among the lightest smokers, whereas dietary fat was most positively associated with risk among the heaviest smokers. Total calories, protein, and retinal were associated with increased risk; there was no relationship between laryngeal cancer and vitamin C, vitamin E, carbohydrate, or dietary fiber. This study again demonstrates the strong association between tobacco and alcohol and laryngeal cancer and also suggests that diets low in carotenoids and high in fat may increase risk.

ISSN:0163-5581    

DOI:10.1080/01635589209514171

出版商:Taylor&Francis Group    

年代:1992

数据来源: Taylor

摘要:

AbstractMale Sprague‐Dawley rats were fed from weaning low (1–5 ppm) and normal (26–50 ppm) vitamin E diets for 30–34 weeks. Dietary fat was also varied from 5% (Experiment 1) to 20% (Experiments 2 and 3). Intestinal tumors were induced by 1,2‐dimethylhydrazine given subcutaneously as 10 weekly doses at 20 mg/kg body wt. Tumor incidence was lower by 30% and burden was 25%‐50% lower for low vitamin E rats than for vitamin E‐replete rats. This result was independent of the fat content of the diet. In Experiment 3, vitamin E and calcium were assessed for their influence on intestinal tumors at two levels, with dietary vitamin E at 5 and 50 ppm and calcium at 0.2% and 1.0% in a 2 x 2 factorial experiment. The high calcium‐low vitamin E diet produced the greatest fall in tumor incidence and burden relative to the other treatments. In this experiment, vitamin E deficiency reduced tumor incidence and calcium supplementation reduced tumor burden, with a significant interaction of the two. However, this group also showed evidence of reduced food intake and kidney change (calcification), which may have confounded the result. This points to a risk associated with this combination of nutrients at these levels in long‐term experiments.

ISSN:0163-5581    

DOI:10.1080/01635589209514172

出版商:Taylor&Francis Group    

年代:1992

数据来源: Taylor

摘要:

AbstractGlutathione (GSH) is an antioxidant and anticarcinogen that is present in plant and animal tissues that form the bulk of the human diet. Recent studies show that GSH is absorbed intact in rat small intestine and that oral GSH increases plasma GSH concentration in humans. To provide a database for epidemiological studies of dietary intake of GSH and risk of diseases in humans, we have measured the content of GSH in the foods listed in the National Cancer Institute's Health Habits and History Questionnaire. Foods were purchased in the Atlanta area and prepared as most commonly consumed in the United States. GSH analyses were performed using a high‐performance liquid chromatography technique with a method of additions to correct for losses during sample preparation. A separate set of samples was run after treatment with dithiothreitol to measure the total of GSH and its disulfide forms (GSH,). The results show that dairy products, cereals, and breads are generally low in GSH; fruits and vegetables have moderate to high amounts of GSH; and freshly prepared meats are relatively high in GSH. Frozen foods generally had GSH contents similar to fresh foods, whereas other forms of processing and preservation generally resulted in extensive loss of GSH. Thus this database will allow researchers to examine the relationship between dietary GSH and risk of cancers and other diseases.

ISSN:0163-5581    

DOI:10.1080/01635589209514173

出版商:Taylor&Francis Group    

年代:1992

数据来源: Taylor

摘要:

AbstractThe anticarcinogenic effect of dietary turmeric on benzo[a]pyrene‐(BP) induced fore‐stomach neoplasia and 7,12‐dimethylbenz[a]anthracene (DMBA)‐induced skin tumorigenesis in female Swiss mice was evaluated. To further elucidate the mechanism of antineoplastic action of turmeric, its effect on the hepatic cytochrome b5, cytochrome P‐450, glutathione, and glutathioneS‐transferase activities was studied in female Swiss mice. Turmeric (2% or 5%) in the diet significantly inhibited the BP‐induced forestomach tumors, and this response was dose and time dependent. The 2% turmeric diet significantly suppressed DMBA‐induced skin tumors in mice. The 5% turmeric diet for seven consecutive days resulted in a 38% decrease in the hepatic cytochrome b5 and cytochromeP‐450 levels. Glutathione content was increased by 12%, and the glutathioneS‐transferase activity was enhanced by 32% in the liver. Our results document a protective effect of turmeric on BP‐induced forestomach and DMBA‐induced skin tumors in mice.

ISSN:0163-5581    

DOI:10.1080/01635589209514174

出版商:Taylor&Francis Group    

年代:1992

数据来源: Taylor

摘要:

AbstractThe incidence of colorectal cancer is lower in Polynesian populations of the South Pacific than in European populations. This difference in incidence of the disease may be, at least partly, related to diet. Dietary fiber is believed to protect against colorectal cancer, and one of the ways it may act is by adsorbing mutagens that are carcinogenic. Very little is known about the chemical composition or the ability to adsorb mutagens of these dietary fibers from South Pacific food plants. In contrast to European food plants, which are mostly dicotyledons, South Pacific food plants are mainly monocotyledons. We isolated cell walls (dietary fiber) from the three edible parts of taro (Colocasia esculenta),which is a monocotyledon and a major South Pacific food plant. The ability of these three unlignified cell‐wall preparations to adsorb the hydrophobic environmental mutagen 1,8‐dinitropyrene was studied. The greatest adsorption occurred with walls from leaf blade, followed by petiole and corm walls, although the differences were not major. The amount of adsorption was intermediate between the low adsorption previously found with unlignified dicotyledon walls (from the flesh of potato tubers and immature cabbage leaves) and the much higher adsorption found with unlignified walls from monocotyledons of the grass and cereal family (Poaceae) (from leaves of seedling Italian ryegrass). These data are consistent with the monosaccharide compositions of the taro wall preparations, which were more similar to those of unlignified walls of dicotyledons than to unlignified walls of the Poaceae. These findings are consistent with the hypothesis that the composition of the dietary fiber determines its adsorptive properties and that there may be important differences between the major dietary fibers of South Pacific and European food plants.

ISSN:0163-5581    

DOI:10.1080/01635589209514175

出版商:Taylor&Francis Group    

年代:1992

数据来源: Taylor

摘要:

AbstractThe carcinogenic effect of flour infested with beetles (Tribolium castaneum),biscuits made of this flour, and 1,4‐benzoquinone (a quinoid secretion of this beetle) was investigated using Swiss albino mice. Force feeding flour infested withT. castaneuminduced liver and spleen tumors (lympholeukemia) in 35.2% of the animals. The tumor incidence was 29% in mice force fed biscuits made of infested flour, and the tumors were located in the liver (lympholeukemia) and breast (adenocarcinoma type A). In animals fed 1,4‐benzoquinone, the tumor incidence was 33.6%, and the tumors were located in the liver and spleen (lympholeukemia). It is speculated that 1,4‐benzoquinone, alone or in combination with other quinoid secretions of the beetles present in the flour, may be responsible for tumor induction in the organs of mice.

ISSN:0163-5581    

DOI:10.1080/01635589209514176

出版商:Taylor&Francis Group    

年代:1992

数据来源: Taylor