摘要:

AbstractEpidemiological data suggest that increased risk of colon cancer is correlated with a higher fecal pH. Although some experimental studies have shown a protective effect against experimentally induced colon cancer by acidifying colonic contents, others have shown that a more acidified colonie content is associated with increased cell proliferation and enhanced tumorigenesis. It is now clear that simply acidifying colonic contents will not consistently result in decreased tumorigenesis. Perhaps the key is how colonie contents are acidified—a decrease in base production or an increase in acid production. Or, more important than luminal pH itself, may be a factor affected by changes in hydrogen ion concentration. This paper reviews the determinants of colonie luminal pH and their dietary sources and discusses important physiological consequences of modifying the pH of colonie contents.

ISSN:0163-5581    

DOI:10.1080/01635589009514091

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractA dietary deficiency of methyl donors, the lipotropes methionine and choline, enhances the activity of hepatocarcinogens in rodents. To determine if the reverse is true, an excess of dietary choline, methionine, or both was fed to male mice given a carcinogenic dose of aflatoxin B1 (AFB1). Fifty weeks following the last dose of AFB1, all survivors were killed then examined for tumor incidence, and samples of nontumorous liver tissue were assayed for activities of mixed function oxidases (MFO). Survival was best in the high‐methionine/high‐choline group, with 36/38 surviving to termination of the study. Survival in the other groups was 35/38, 30/70, 33/38, and 34/37 in control with no AFB1, control with AFB1, groups with high methionine, and high choline, respectively. Combined adenoma/ carcinoma incidence was 8/38, 30/37, 21/38, 20/37, and 10/38 in groups control with no AFB1, control with AFB1, high methione with AFB1, high choline with AFB1, and high choline and high methionine with AFB1, respectively. CytochromeP450‘cytochrome B5, cytochromeC,and ethylmorphineN‐demethylase activities were all increased over controls, with most marked increases in the cytochromeP450 and ethylmorphineN‐demethylase activities. The data presented here document a protective effect of dietary methyl donors on AFB,‐induced hepatocarcinogenesis in mice probably acting, in part, via activation/ detoxification mechanisms favoring an increased balance in detoxification of AFB1.

ISSN:0163-5581    

DOI:10.1080/01635589009514092

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractA single 2‐mg dose of garlic oil applied 30 minutes Before a single carcinogenic dose of 7, 12‐dimethylbenz[a]‐anthracene (DMBA) inhibited papilloma production in Sencar mice. The three groups were controls (Group 1), garlic oil applied 30 minutes before DMBA (Group 2), and garlic oil applied 30 minutes after DMBA (Group 3). The percents of mice with papillomas at 20 weeks were 94, 72, and 79, respectively. The decreases in Groups 2 and 3 were significant. The number of papillomas per mouse was 4.2±0.5 (Group 1), 2.3±0.8 (Group 2), and 3.4±0.6 (Group 3). The decrease in Group 2 was significant. A single 5‐mg dose of garlic oil maximally inhibited DMBA‐induced epidermal DNA synthesis by 86% when applied two hours before the carcinogen. Two‐stage promotion in DMBA‐initiated Sencar mice was achieved by twice‐weekly applications of 8.5 nmol of 12‐O‐tetradecanoytphorbol‐13‐acetate (TPA) for 2 weeks followed by twice‐weekly applications of 8.5 nmol of mezereinfor 18 weeks. The oils were applied 30 minutes after each promotion by TPA or mezerein. Single doses of 1 mg onion or garlic oil inhibited the first and second stages of promotion.The groups used were control (Group 1), garlic oil applied after stage 1 (Group 2), onion oil applied after stage 1 (Group 3), propenyl sulfide applied after stage 1 (Group 4), garlic oil applied after stage 2 (Group 5), onion oil applied after stage 2 (Group 6), and propenyl sulfide applied after stage 2 (Group 7). The percent of mice with papillomas was significantly decreased by all agents in Groups 2–7. The data are 81, 83, 91, 68, 96, and 86, respectively. The number of papillomas per mouse was significantly reduced by onion and garlic oils but not by propenyl sulfide. The data are 9.4±0.8, 6.3±0.7, 7.4±0.5, 9.2±1.2, 3.7±0.9, 6.2±0.6, and 9.1±1.4 for Groups 1–7, respectively. Onion and garlic oils inhibited the TPA‐stimulated DNA synthesis when given as single doses of 5 mg one hour before TPA. The inhibition by garlic oil was most effective when given one hour before TPA but was evident when given from two hours before to two hours after TPA. These results, and those of others (AS Sadhana,Cancer Lett,40, 193–197, 1988), who obtained inhibition of initiation, indicate that onion and garlic oils inhibit all stages of mouse skin tumorigenesis. Inhibition of DNA synthesis may be part of the mechanisms involved.

ISSN:0163-5581    

DOI:10.1080/01635589009514093

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractThe chemopreventive effects ofß‐carotene are usually attributed to its antioxidant properties. To determine the effects ofß‐carotene supplementation on different parameters of oxidative metabolism, 15 normal young male subjects (18–30 yrs) were placed on a carotenoid‐free liquid diet for two weeks prior to entry into the study. Blood was then measured for five carotenoids, retinol, retinyl palmitate, retinol‐binding protein,α‐tocopherol, vitamin C, zinc, lipid peroxides, and neutrophil Superoxide production. Absorption tests were performed with 15 mg ofß‐carotene to determine absorption curves for each subject. Subjects were then divided into two groups and given either 15 (n =7) or 120 (n =8) mg ofß‐carotene daily for four weeks along with the same carotenoid‐free liquid diet. The absorption test and the blood measurements were repeated. After repletion withß‐carotene, serum lipid peroxide levels decreased in both groups (p<0.05), but no other changes were noted in either the neutrophil superoxide production or in the levels of any of the vitamins measured. In contrast to vitamin E, the superoxide scavenging ability ofß‐carotene apparently does not contribute to its effects in lowering serum lipid peroxide levels.

ISSN:0163-5581    

DOI:10.1080/01635589009514094

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractThe inhibitory effect of topical garlic extract on 7,12‐dimethylbenz[a]anthracene (DMBA)‐induced oral carcinogenesis in Syrian hamsters was studied to define the local anti‐carcinogenicity of garlic. Two other chemicals, benzo[a]pyrene (BP) and 5‐nitroso‐2,4,6‐triaminopyrimidine (NTP), were also testing materials. All chemicals were applied topically to the cheek pouches of hamsters. The tumorigenesis and architecture of blood vessels on pouch mucosa were examined periodically. The amount of DNA synthesis andγ‐glutamyl transpeptidase activity of the pouch mucosa was detected when the animals were killed. The anticarcinogenicity of garlic and other chemicals was determined by comparing the data obtained from all the examinations with each other and with those shown in the control animals. The apparent local inhibitory effect of garlic on DMBA‐induced carcinogenesis was demonstrated, which was even stronger than those of BP and NTP. It suggests that garlic could be developed as a potential chemopreventive agent for oral cancer. This study also disclosed that the examination parameters used were reliable and reproducible. Therefore, they might be utilized for screening the anticarcinogenicity of materials or for early diagnosis of carcinogenesis. The animal model could also be adopted appropriately in evaluating the inhibitory effect of other materials on experimental carcinogenesis because of its comparability.

ISSN:0163-5581    

DOI:10.1080/01635589009514095

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractData from a population‐based multicenter case‐control study were examined to assess for the first time the relationship between diet and oral and pharyngeal cancer among blacks. An increased intake of fruits and vegetables was associated with a decreased risk for oral cancer among both men and women, although the protective effect was stronger among men. Risk also declined in both sexes with an increase in the consumption of vitamin C and fiber and in men only for carotene and vitamin E. In both sexes, no associations were found with an intake of smoked, pickled, or charcoal‐grilled meats or of hot beverages. However, the consumption of nitrite‐containing meats was linked to increased risk among men. The dietary patterns of risk for blacks were generally similar to those previously reported for whites; however, a lower consumption of fruits and vegetables among blacks in this study may contribute to their higher rates of oral and pharyngeal cancer.

ISSN:0163-5581    

DOI:10.1080/01635589009514096

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractThe relationship between the consumption of salt and the risk of gastrointestinal cancer was examined using data from a case‐control study conducted in northern Italy. The study was conducted on 526 incident cases of gastric cancer, 621 of colon cancers, 382 of rectal cancers, and 1,223 controls admitted to hospital for acute, nonneoplastic, nondigestive tract disorders. Compared with those for people with low salt intakes, the relative risks (and 95% confidence intervals) for those with intermediate and high salt intakes were 1.3 (1.0–1.8) and 1.2 (0.8–1.7) for stomach, 1.0 (0.8–1.3) and 1.1 (0.8–1.5) for colon, and 1.2 (0.9–1.6) and 0.9 (0.6–1.3) for rectum. None of the trends in risk were statistically significant, and the risk estimates were not materially modified by allowance for major identified potential confounding factors. Thus, this study gives little support to the existence of any strong association between salt intake and gastrointestinal cancers. However, in view of the results obtained and of the uncertainties of salt intake measurement, the possibility exists of a real, although moderate, association of salt intake with gastric cancer.

ISSN:0163-5581    

DOI:10.1080/01635589009514097

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractThis study determined the pathological effects of niacin/tryptophan deficiency on the esophagus. Nine patients with severe clinical pellagra and 31 age‐and sex‐matched controls were assessed. All pellagrins had an esophagitis varying from severe to mild. The esophagitis improved in five patients following six to seven days of vitamin therapy. The relationship between vitamin deficiencies and esophageal cancer is discussed.

ISSN:0163-5581    

DOI:10.1080/01635589009514098

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractThis investigation studied the effects of a shift from a mixed diet to a lactovegetarian diet on some cancer‐associated bacterial enzymes in human feces (ß‐glucuronidase,ß‐glucosidase, and sulphatase). Three months after the shift to the lactovegetarian diet, there was a significant decrease inß‐glucuronidase,ß‐glucosidase, and sulphatase activities per gram feces wet weight (p<0.05,<0.05, and<0.001, respectively). In contrast, glucuronide and glucoside hydrolysis remained unchanged per gram dry weight, although sulphatase activity was still significantly lowered when expressed this way (p<0.01). However, the fecal excretion increased significantly (p<0.05). Part of the explanation for the decreased enzyme activities is obviously a dilution effect, because much of the increased fecal weight after the shift in diet was associated with a higher water content. The higher water content was probably due to a higher fiber intake (p<0.001). Thus, the results in this paper indicate that a change from a mixed diet to a lactovegetarian diet leads to a decrease in certain enzyme activities proposed to be risk factors for colon cancer.

ISSN:0163-5581    

DOI:10.1080/01635589009514099

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractThe effect of sampling site and proximity of malignant tumor on the relative fatty acid composition of human breast adipose tissue was studied in 10 cases of breast cancer. The four anatomic quadrants of breast did not statistically significantly differ from each other in relation to any of the 30 fatty acids studied. Proximity of the malignant tumor did not affect the relative fatty acid composition of fat when compared with more distant sampling sites. Representative samples of breast adipose tissue for fatty acid composition analysis can be obtained from tissue adjacent to the tumor.

ISSN:0163-5581    

DOI:10.1080/01635589009514100

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor