摘要:

AbstractSixty young adult Syrian hamsters were divided into five groups. Group 1 and Group 2 animals were treated with 0.25% dimethylbenz(a)anthracene (DMBA), painted on their left buccal pouches thrice weekly for 20 weeks. Starting at 12 weeks, at which time there was clinical evidence of leukoplakia and initial tumor formation, Group 2 animals received 10 mg retinyl acetate 3 times/week in a 5% solution in peanut oil, while Group 1 animals received only peanut oil. Two animals in Group 1 and two animals in Group 2 were sacrificed weekly from week 12 to week 20. Left buccal pouches were examined, tumors were counted, and tumor size was measured. Group 3 animals were untreated controls, Group 4 animals were retinyl acetate controls, and Group 5 animals received only peanut oil. It was found that DMBA‐treated animals receiving retinyl acetate from week 12 to week 20 developed fewer tumors, and their average tumor size was less than that in DMBA‐treated animals not receiving retinyl acetate. It appears that retinyl acetate, administered systemical‐ly, can retard tumor development even after leukoplakia has been established and tumors have begun to develop.

ISSN:0163-5581    

DOI:10.1080/01635588309513788

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

摘要:

AbstractThe effect of a 20% wheat bran dietary supplement on pancreatic growth and on the content and synthesis of pancreatic RNA and DNA was examined in male Sprague‐Dawley rats fed defined diets for 4–5 weeks. Nutrient intake and body weight gain were similar in the control group (fed a fiber‐free diet) and the groups fed the wheat bran supplement. The wheat bran diet produced no significant change in pancreatic weight, protein, RNA content, or DNA content, but was associated with a 28.8% fall in pancreatic DNA synthesis, measured by [3H]thymidine incorporation into DNA, when compared with the controls (p<0.05). When rats were injected with 50 mg/kg of 5‐fluorouracil (two injections, one week apart), those fed wheat bran exhibited a 40.1% increase in pancreatic wet weight (p<0.005) and a 24.5% decrease in RNA content (p<0.001), when compared to controls fed a fiber‐free diet. RNA synthesis, measured by the incorporation of32P into RNA, increased 3.6‐fold in rats fed wheat bran, when compared with controls (p<0.01). These results suggest that wheat bran should be tested further for any inhibitory action on pancreatic carcinogenesis and for its modifying effect on 5‐fluorouracil toxicity.

ISSN:0163-5581    

DOI:10.1080/01635588309513789

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

摘要:

AbstractThe influence of potassium nitrate on the formation of nitrosamines in salami was studied. Samples of salami were prepared, with and without the addition of potassium nitrate. Under the conditions of the experiment, potassium nitrate did not represent a source of either nitrite or nitrosamines. Independently of the presence of potassium nitrate in the sample formulation, thegrowth of bacterial flora reached a maximum in the first 20 days of the ripening process.

ISSN:0163-5581    

DOI:10.1080/01635588309513790

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

摘要:

AbstractMutagens detected withSalmonella typhimuriumstrain TA 98 in the presence of liver S9 mix were extracted from potato slices, but not pure potato starch, after frying in oil. No mutagenic activity was detected using strain TA 100, in the presence or absence of S9 mix with either fried potato slices or potato starch. Mutagenic activity was detected at frying temperatures of 140°C and above. The mutagenic activity was limited to the outer portion of the fried potato slices and increased with frying time and temperature. Mutagenic activity ratios for extraction with both (NH4)2SO4/ NH4 OH and Na2 SO4 /NaOH were similar.

ISSN:0163-5581    

DOI:10.1080/01635588309513791

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

摘要:

AbstractThis study was undertaken to investigate the possible antimutagenic effects of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) on 3,2´‐dimethyl‐4‐aminobiphenyl (DMAB)‐induced mutagenicity, using the AmesSalmonella/mammalian microsome system. The addition of 100–250μg of BHT or 25–500μg of BHA/plate was found to inhibit DMAB‐induced mutagenicity inSalmonellastrains TA 98 and TA 100. In TA 100, the mutagenicity was further inhibited with the addition of S9 prepared from the livers of rats fed a 0.6% BHT diet as compared to S9 from the animals fed a diet containing no BHT.

ISSN:0163-5581    

DOI:10.1080/01635588309513792

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

摘要:

AbstractThe effect of feeding skim milk fermented byStreptococcus thermophilusorLactobacillus bulgaricuson the incidence of chemically induced colon tumors was studied in rats. Weanling Fisher‐344 rats were fed chow plus skim milk (SM), chow plus SM fermented byS. thermophilus,chow plus SM fermented byL. bulgaricus,or chow plus water until sacrifice at 36 weeks, or before if moribund. Colon tumors were induced by s.c. injections of 1,2‐dimethylhydrazine hydrochloride during weeks 3 through 22. The control (chow + water) group received saline injections. The survival rate of the rats fed fermented milks was significantly higher than that of the rats fed nonfermented milk. The latter had a significantly higher incidence of ear‐duct tumors than the rats receiving fermented milk. The percentage of rats showing colon tumors was similar among all three experimental groups. The control group did not have any tumors. The rats receiving fermented milk had a significantly higher incidence of small‐intestine tumors than those receiving nonfermented milk. The rats onS. thermophilusmilk had the lowest percentage of malignant colon tumors of the three experimental groups. Results indicated that the feeding of fermented milks altered the metabolism of 1,2‐dimethylhydrazine and shifted the target organ from the ear duct to the small intestine. In addition, the colon tumor distribution for the fermented‐milk groups appeared to shift toward the anus.

ISSN:0163-5581    

DOI:10.1080/01635588309513793

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

摘要:

AbstractPrimary liver‐cell cancer (PLC) mortality ratios, computed from death certificate records compiled by the National Center for Health Statistics, for the periods 1968–1971 and 1973–1976 were sorted by race, sex, urbanization, and region. From this sort, rural white males from the Southeast and the“North and West”; regions were selected for comparison of mortality ratios and past dietary exposure to aflatoxin. Based on projections of recent aflatoxin contamination information back to the 1910–1960 period, and estimates of corn and peanut usage from household food consumption surveys relating to that period, the expected average daily inges‐tion of aflatoxin B1 for each group was calculated (Southeast, 13–197 ng/kg bw; North and West, 0.2–0.3 ng/kg bw). An age‐adjusted excess PLC mortality ratio was observed for the Southeast population when compared with the“North and West"—10% excess PLC deaths at all ages, and 6% excess PLC deaths for the 30–49 year age‐group—but although the difference was in the expected direction in relation to projected past exposure to aflatoxin, it was far from the many fold difference that would have been anticipated from experiments with rats and from prior epidemiological studies in Africa and Asia. The remaining major portion of the PLC mortality in the Southeast may be attributed to many unidentified causes for which the two populations that were compared were not controlled, leaving in doubt the validity of any attribution of the excess PLC mortality to aflatoxin ingestion. A considerable excess over average US PLC mortality ratios was seen for all Orientals resident in the US and for urban black males. Occurrence of PLC in Orientals has been related to the presence of markers for hepatitis B virus in the blood serum of affected individuals.

ISSN:0163-5581    

DOI:10.1080/01635588309513794

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

摘要:

AbstractThe antitumor effects of vitamin A and its related substances, vitamin E, vitamin K,ß‐carotene, ubiquinone, phytol, and sgualene, were examined using a syngeneic murine tumor system. Intraperitoneal administration of these substances (0.19μmol/mouse/day) slightly suppressed the growth of Meth A fibrosarcoma cells inoculated s.c. into Balb/c mice. Administration of all test substances exceptß‐carotene significantly suppressed the growth of Meth A fibrosarcoma cells rechallenged in Meth A‐primed mice on day 10, but did not influence the growth of Meth 1 fibrosarcoma cells (another syngeneic tumor of Balb/c origin) rechallenged in Meth A‐primed mice on day 10. The growth of Meth A tumor cells was suppressed when Meth A was inoculated together with lymph node cells obtained from the Meth A‐primed Balb/c mice treated with vitamin A, vitamin E, phytol, or squalene. Our findings suggest that certain constituents in green‐yellow vegetables may contribute to the prevention of cancer by augmenting an immunological response against tumor cells in the early stages of carcinogenesis.

ISSN:0163-5581    

DOI:10.1080/01635588309513795

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

ISSN:0163-5581    

DOI:10.1080/01635588309513796

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor

ISSN:0163-5581    

DOI:10.1080/01635588309513797

出版商:Taylor&Francis Group    

年代:1983

数据来源: Taylor