ISSN:0163-5581    

DOI:10.1080/01635589009514080

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractA large body of experimental work has revealed that protease inhibitors (PI) are highly effective suppressors of carcinogenesis. Little is known about the level of PI activity in the diet of the US population. In the present study, we assayed the levels of PI activity in dietary samples from 31 free‐living subjects who saved duplicate portions of all foods consumed over two 24‐hour periods, six months apart. The majority of samples (90%) contained detectable PI activity; 82% contained trypsin inhibitory activity; 61% contained chymotrypsin inhibitory activity. Of those samples containing chymotrypsin inhibitory activity, 87% also contained trypsin inhibitory activity. The median concentration of soluble chymotrypsin inhibitory activity present in these samples was 6.5μg/g food (range 0–150μg/g food), whereas the median concentration of soluble trypsin inhibitory activity was 14.5μg/g food (range 0–465μg/g food). We conclude that a) human diet samples contain both chymotrypsin and trypsin inhibitory activity, b) the levels of PI in some of these samples was similar to that found to be anticarcinogenic in animal studies, and c) due to the large within‐subject variation in PI intake, assessment of long‐term dietary intake in epidemiological studies will be necessary to accurately classify subjects according to PI intake.

ISSN:0163-5581    

DOI:10.1080/01635589009514081

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractThis is a preliminary report that shows that supplemental potassium partially prevents 1,2‐dimethylhydrazine (DMH) induction of tumors of the small intestine in Sprague‐Dawley rats. Male rats were injected weekly with 20 mg DMH/kg body wt for 20 weeks. Potassium chloride was provided in the drinking water one week before the first DMH treatment and was continued until sacrifice 14 weeks after the last DMH treatment. There were four groups of rats and they were identified as follows: DMH, DMH + K, K, and untreated control. Based on 24‐hour food and water consumption data and food and water compositions, rats provided 0.5% potassium (from KCl in the drinking water) were ingesting 287.5±9.2 mg potassium per 24 hours (K/Na = 4.18) and the unsupplemented groups were ingesting 180.3±18.4 mg potassium per 24 hours (K/Na = 2.62). At sacrifice, the incidence of DMH‐induced small intestinal tumors was significantly (p<0.05) reduced from 46% (6/13) in the DMH group to 6% (1/17) in the DMH + K group (p<0.05). The potassium supplement also significantly (p0.05). Based on the complete blood count and other blood parameters measured, the level of potassium supplement used induced no apparent toxic effects. The liver glutathione S‐transferase activity was increased in potassium‐supplemented groups, suggesting that prevention of DMH carcinogenesis by potassium might at least be in part attributed to the enhancement of a detoxification pathway.

ISSN:0163-5581    

DOI:10.1080/01635589009514082

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractAn AIN‐76A diet supplemented with miso (Japanese soybean paste) reduced the incidence (p = 0.05, Fishers exact test) and delayed the appearance (p = 0.04, log rank test) of dimethylbenz[a]anthracene (DMBA)‐induced mammary adenocarcinomas in female Sprague‐Dawley rats. A NaCl‐supplemented AIN‐76A diet (containing the same amount of NaCl as in the miso‐supplemented diet) also delayed the appearance of tumors (p = 0.02, log rank test) compared with the AIN‐76A control diet. The miso‐and NaCl‐supplemented diet treatment groups showed a trend toward a lower number of cancers per animal, a trend toward a higher number of benign tumors per animal, and a trend toward a lower growth rate of cancers compared with controls. However, no statistical differences in the total number of tumors per animal or growth rate of the cancers were observed in the miso, NaCl, and control groups. Both miso and NaCl supplementation resulted in increased water intake and urine output but no change in the growth of the animals. These data suggest that miso consumption may be a factor producing a lower breast cancer incidence in Japanese women.

ISSN:0163-5581    

DOI:10.1080/01635589009514083

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractEffects of different dietary lipids and excess vitamin E on plasma and hepatic concentrations ofβ‐carotene were evaluated in rats fed diets containing a large excess (0.2%) ofβ‐carotene. Male weanling Wistar Kyoto rats were fedβ‐carotene‐supplemented diets containing various dietary lipids as follows: Group I, a saturated fat (coconut oil); Group II, a monounsaturated fat (olive oil); Group III, a polyunsaturated fat rich inω‐6 fatty acids (safflower oil); Group IV, same as Group III plus vitamin E; and Group V, a polyunsaturated fat rich inω‐3 fatty acids (menhaden oil). All diets contained 2% saf flower oil to provide sufficient amounts of linoleic acid (an essential fatty acid). Rats were killed after six weeks of feeding the various diets, and the concentrations of Q‐carotene and vitamin A were determined in plasma and liver. Plasma vitamin A levels were not altered by any of the dietary lipids or by an excess of vitamin E. The concentrations ofβ‐carotene in plasma were the lowest in rats fed the diet containing menhaden oil. The feeding of the diet containing an excess of vitamin E also resulted in a significant decrease in plasmaβ‐carotene concentration. Similarly, the hepaticβ‐carotene concentration was also reduced to about one‐half in rats fed the diet containing an excess of vitamin E. Liverβ‐carotene concentration was higher in Groups II and III than in the other three dietary groups. Hepatic vitamin A concentrations were also affected by the type of dietary fat. The highest levels were observed in rats fed the coconut oil diet; the lowest level of vitamin A was in rats fed menhaden oil (Group V). The results of this study suggest that the type of dietary fat and an excess of vitamin E can have a significant effect on 0‐carotene and vitamin A stores in liver and onβ‐carotene content of plasma.

ISSN:0163-5581    

DOI:10.1080/01635589009514084

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractThe effects of feeding olive and safflower oils on lipid and fatty acid composition of mammary tumors, plasma lipids and lipoproteins, and the nuclear magnetic resonance (NMR) spectra of plasma were investigated in rats. 7–12‐Dimethylbenz[a]anthracene (DMBA)‐and placebo‐intubated male Sprague‐Dawley rats were fed 20% fat diets containing 18: 2n‐6 (wt/wt) from either high‐linoleic safflower oil (SL, 14.6% 18: 2n‐6), high oleic safflower oil (SO, 3.4% 18: 2n‐6), olive oil (OO, 1.1% 18: 2n‐6), or olive oil supplemented with 18: 2n‐6 (OL, 3.4% 18: 2n‐6) for 16 weeks. Our result indicated that tumor composition of18: In‐9 and 18: 2n‐6 reflected the diet, but tumor neutral lipid (NL) was more reflective of diet than was tumor phospholipid (PL). The 20: 4n‐6 content of tumor PL was constant in all of the dietary groups despite threefold higher levels of 18: 2n‐6 in tumor PL from animals fed SL than from those fed SO, OO, orOL diets. This suggests a possible feedback inhibition of ?6‐desaturase by the higher content of 18: 2n‐6 associated with SL feeding. No diet effects were obtained for tumor total lipid, NL, PL, cholesterol, and triglyceride contents. Plasma lipoprotein changes were more reflective of diet than tumorigenesis except for apolipoprotein‐E, which was lower, and for very low‐density lipoprotein cholesterol and low‐density lipo protein, which were higher in tumor‐bearing rats. Plasma NMR analysis indicated no difference in the average line widths of the methyl and methylene resonances for tumor‐bearing and nontumor‐bearing rats fed any of the diets.

ISSN:0163-5581    

DOI:10.1080/01635589009514085

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractA high intake of salted food is thought to be related to the high incidence of stomach cancer in Japan. In the present study, female F344 rats were divided into four groups. They were fed a nutritionally deficient purified diet (Group 1) and standard purified diet (Group 3) for 113 weeks and the same diets supplemented with salted cuttlefish guts, broiled, salted, dried sardines, pickled radish, and soy sauce (Groups 2 and 4). The incidence of papillomas and ulcers of the forestomach was highest in Group 4, which was given the standard diet supplemented with the salty food materials (p<0.05). These results suggest the importance of salted food as a suspicious causal factor in human stomach cancer in Japan.

ISSN:0163-5581    

DOI:10.1080/01635589009514086

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractIn a case‐control study, serum levels of vitamins E, C, and A, carotenoids, total cholesterol, and retinol‐binding protein along with smoking levels were studied on 59 persons newly diagnosed with lung cancer and also on matched hospitalized controls. The relative risk for smoking increased with the number of pack years of cigarettes smoked. Cases had significantly lower serum levels of carotenoids, vitamin E, and total cholesterol. Adjustment for serum cholesterol levels diminished the case‐control difference for serum carotenoid levels and reduced the case‐control difference for serum vitamin E levels. The results indicate that serum vitamin E may also be associated with lung cancer, possibly to a greater degree than serum retinol (vitamin A) is associated with lung cancer.

ISSN:0163-5581    

DOI:10.1080/01635589009514087

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractGroups of 20 female Ha/ICR mice were initiated with 25μg 7,12‐dimethyl‐benz[a]anthracene (DMBA) and promoted one week later with topical treatments three times per week of 5μg phorbol myristate acetate (PMA) and/or onion oil or garlic oil. Promotion was continued for 49 weeks in most experiments. Promotion was continued for 60 weeks in the experiment that evaluated the effect of time intervals between PMA and garlic oil. All experiments were conducted with 0.2 nil acetone solutions of agents. Onion oil, but not garlic oil, was a weak promoter in mouse skin. A 1‐mg dose produced five papillomas in three mice and one carcinoma in 330 days (18 survivors). The 10‐mg dose was more effective; it produced cumulative yields of 56 papillomas in 14 mice and 7 carcinomas in 4 mice in 345 days (14 survivors). Onion oil is neither an initiator nor a whole carcinogen. The effects of intervals between PMA and a 1‐mg dose of onion or garlic oil were determined. These intervals were—2 hrs,‐1 hr,‐0.5 hr, +0.5 hr, +1 hr, and +2 hrs with respect to time of PMA application. Maximal inhibition of papillomas by onion oil was observed at the + 0.5‐hr interval and was similar to that previously reported. Garlic oil is not a promoter. It inhibited papillomas at the +0.5‐hr, +1.0‐hr, and +2.0‐hr intervals but did not appear to affect carcinoma production.

ISSN:0163-5581    

DOI:10.1080/01635589009514088

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor

摘要:

AbstractCalcium intake inhibits growth of colon cancer in vivo, the mechanisms of which are not fully elucidated. The objective of this study was to determine whether Ca2+directly affects the growth of colon cancer cells in vitro and to compare the effects of Ca2+on the growth of several gastroenteropancreatic cancer cells, including mouse colon cancer (MC‐26), human colon cancer (Lo Vo and WIDR), human gastric cancer (AGS and SII), and human pancreatic cancer (PANC‐1 and MIA) cells. All tumor cell lines tested grew in medium containing low concentration (approx 0.16 mM) of Ca2+. Higher concentrations of Ca2+significantly inhibited the growth of all three colon cancer cell lines tested but had no significant effect on proliferation of the stomach and pancreatic cancer cell lines. Growth of AGS cells, in the presence of 0.1 or 0.5 mMEGTA (resulting in the loss of the extracellular Ca2+) was similar to that observed in the absence of EGTA, indicating that AGS cells were relatively insensitive to loss of extracellular Co2+. In the presence of TMB‐8, an inhibitor of intracellular Ca2+release, the growth of colonic cancer cell lines was inhibited in a dose‐dependent manner, indicating that a minimum basal level of intracellular Ca2+was required for continued proliferation of colon cancer cells. The stomach cancer cell lines (AGS) was once again less sensitive to the effects of TMB‐8 than were the colon cancer cells, indicating an inherent difference in Ca2+requirements and sensitivity to Ca2+for growth of different gastroenteropancreatic cancer cells in vitro. These results further demonstrate that in contrast to normal cells, all tumor cells tested can continue to proliferate in the presence of low concentrations of extracellular Ca2+(approx<0.16 mM) and that higher concentrations of Ca2+specifically and directly inhibit growth of human and mouse colon cancer cells. The latter results may provide an additional explanation for the mechanism by which intake of dietary calcium decreases the risk of developing colon cancers.

ISSN:0163-5581    

DOI:10.1080/01635589009514089

出版商:Taylor&Francis Group    

年代:1990

数据来源: Taylor