Juanell N. Boyd

Modification by beet and cabbage diets of aflatoxin B1-induced rat plasma α-foetoprotein elevation, hepatic tumorigenesis, and mutagenicity of urine

Weanling male Fischer rats were fed a purified diet or diets containing 25% (w/w) freeze-dried ground beets or cabbage with or without 1 ppm aflatoxin B1 (AFB1) for 26 wk. In 3-7 wk the cabbage diet diminished, while the beet diet enhanced AFB1-induced plasma alpha-foetoprotein (AFP) elevation. When the experiment was extended to 42 wk by maintaining the animals on the purified (basal) diet for a further 16 wk the rats that had consumed AFB1 in the beet diet had 72 +/- 14 tumours/liver (mean surface diameter of tumours, 6.13 +/0 4.69 mm); animals that had been given AFB1 in the control diet had 30 +/- 16 tumours/liver (mean surface diameter, 4.36 +/- 3.16 mm); rats that had been given AFB1 in the cabbage diet had 13 +/- 5 tumours/liver (mean surface diameter, 4.28 +/- 2.89 mm). In the Salmonella/mammalian microsomal test, urine from rats fed AFB1 with beets caused significantly (P less than 0.05) more revertants in Salmonella typhimurium strain TA98 than did urine from rats fed AFB1 with purified or cabbage diets. The beet- and cabbage-containing diets had no effect on the plasma AFP concentration, hepatic tumorigenesis, or the mutagenicity of urine in rats receiving no AFB1. The evidence suggests that non-nutrient components of common vegetables may influence the response to chemical carcinogens, and that AFP determinations are useful in the rapid identification of dietary factors that modify carcinogenesis.

Hepatic glutathione S-transferase activity and aflatoxin B1-induced enzyme altered foci in rats fed fractions of brussels sprouts

The aim of the present study was to determine whether the liver cytosol detoxication enzymes, glutathione S-transferases (GSTases) as well as gamma-glutamyl transpeptidase (GGT) foci induced by aflatoxin B1 (AFB) were changed by feeding weanling rats diets containing brussels sprouts, a glucosinolate fraction of brussels sprouts (extract), or a non-glucosinolate fraction (residue). All 3 of these diets induced high levels of hepatic GSTase specific activity as compared to purified-basal diet fed control rats. The brussels sprouts and the extract treatments, but not the residue dietary treatment, inhibited hepatic GGT foci induced by AFB. Thus, glucosinolates and non-glucosinolate fractions of brussels sprouts induce hepatic enzymes involved in detoxication mechanisms but the non-glucosinolate compound(s) apparently are not involved in all chemical carcinogen metabolic processes.

Inhibition of Aflatoxin-Induced Serum α-Fetoprotein in Rats Fed Cauliflower

Summary The highly sensitive competitive binding radioimmunoassay showed an increased level of serum AFP in Fischer male rats fed 1 ppm of AB1 in a semipurified diet for 5 weeks. A 20% cauliflower diet significantly reduced serum AFP and increased hepatic MFO activity. The results of this study suggests that the lowered serum AFP predicts dietary cauliflowers protective action against AB1 -induced hepatocarcinoma.

Safety Evaluation of Vegetables Cultured on Municipal Sewage Sludge-amended Soil

Cabbage, beets, green beans, and butternut squash were grown in control and municipal sewage sludge-treated experimental plots. Freezedried edible portions of each vegetable fed at 25% of the diet to male Fischer rats for 12 weeks, indicated no differences in dietary intake or weight gain, nor were there any differences in blood levels of alpha-fetoprotein, a marker for hepatic preneoplastic transformation. Sludge-grown vegetables did not cause any differences in relative liver weight or in activity of the hepatic mono-oxygenases, aminopyrene-N-demethylase, orp-nitroanisole-O-demethylase, when compared to the same vegetable grown on control soil. There were no effects attributable to the sewage sludge treatment on liver cell ultrastructure. The level of cadmium in the kidneys of rats fed sludge-grown beets was twice that of the controls. The results of mutagenesis testing withS. typhimurium and microsomes (S-9) activation indicated a positive dose response with extracts of sludge-grown beans and in the urine of rats consuming sludge-grown beets. Although no overt toxicologic responses were observed in rats fed sludge-grown vegetables, these positive mutagenic changes create uncertainties in evaluation of potential risks involved in using municipal sludge on food-producing land.

Changes in preneoplastic response to aflatoxin B1 in rats fed green beans, beets or squash

Weanling male Fischer rats were fed diets containing 25% freeze-dried green beans, beets or squash either with or without 1 ppm aflatoxin B1 for 8 wk. Plasma alpha-foetoprotein concentrations were determined weekly from wk 4 to 7. During wk 8 the animals were killed and hepatic sections were stained for gamma-glutamyl transpeptidase. All three vegetable diets, as compared to the basal semi-purified diet, enhanced both aflatoxin-B1-induced elevation of plasma alpha-foetoprotein and aflatoxin-B1-induced emergence of hepatic cell foci of gamma-glutamyl transpeptidase. The data suggest that these vegetables contain natural factors that enhance aflatoxin B1 carcinogenicity.

Toxicologic studies associated with the agricultural use of municipal sewage sludge and health effects among sewage treatment plant workers

The proposed use of municipal sewage sludges as soil amendments on agricultural land involves potential health risks. Sludges may contain toxic heavy metals, synthetic organics, and pathogens. Studies of animals inhabiting sludge-amended soils, or foraging on crops grown on such soils, have shown an increased deposition of cadmium and polychlorinated biphenyls in animal tissues, hepatic microsomal enzyme induction, altered blood profiles, appearance of mutagens in blood and excreta, and lowered feed intake, feed efficiency, and milk production. Epidemiologic evidence of possible adverse health effects among sewage plant workers exposed to aerosolized pathogens or synthetic organic vapors during wastewater treatment or land spreading of sludge is still inconclusive. Other possible deleterious environmental effects include pollution of groundwater and toxicity to birds consuming worms or insects inhabiting sludge-treated soils.

α-fetoprotein and γ-glutamyl transpeptidase response in rats fed aflatoxin B1

Abstract Weanling, male, Fischer rats were fed a semipurified diet containing 0, 0.1, 0.5, 1.0, or 2.0 ppm aflatoxin B 1 (AB 1 ). Plasma α-fetoprotein (AFP) concentrations were determined weekly during weeks 4 to 7. During Week 8, animals were killed and hepatic sections were histochemically stained for γ-glutamyl transpeptidase (GGT). Plasma AFP concentrations increased linearly with increasing level of dietary AB 1 ( Y = 24.9 + 27.0 X ; r = 0.90). There was a corresponding increase in the percentage of hepatic section area stained positively for GGT ( Y = 6.55 + 11.1 X ; r = 0.95). This study suggests that AFP and GGT may both be useful markers for dose-response relationships to hepatocarcinogens.

A Comparison of the Response of Woodchucks and Rats to Variations in Dietary Lipotrope and Protein Content

Juvenile woodchucks and weanling Fisher F344 rats were fed purified diets with or without supplemental lipotropic factors (choline, methionine, folic acid and vitamin B-12). The diets contained 10 or 20% protein. Lower weight gain due to low protein was observed in both species, while lipotrope depletion resulted in lower gain in male rats only. Urinary excretion of formimino-glutamic acid was higher due to low lipotrope in both species, as was relative liver weight. In rats, lipotrope depletion resulted in hepatic fatty metamorphosis at both levels of dietary protein with the low protein diet resulting in more severe lesions. No liver lesions were observed in woodchucks fed low lipotropes at the higher level of dietary protein, but fatty metamorphosis was observed in those fed the lower protein diets. The lesion was more severe in the low lipotrope group. The woodchuck appears to be less sensitive than the rat to induction of fatty liver by lipotrope deficiency, although the lesion was induced by lowering dietary protein.

Plasma α-Fetoprotein Elevation and Mutagenicity of Urine as Early Predictors of Carcinogenecity in Benzo(α)Pyrene Fed Rats

ABSTRACTWeanling male Fischer rats were fed purified diets containing 0, 1, 100, or 1,000 ppm benzo(α)pyrene (BAP) for 6 weeks or 0, 1, or 100 ppm BAP for 3 weeks, then the same diets with or without 500 ppm sodium phenobarbital (PB) for an additional 5 weeks. Blood plasma α-fetoprotein (AFP) was determined at one to two week intervals. Urine, collected for eight hours during the sixth or eighth week of treatment, was tested for mutagenicity with S. typhimurium strain TA98 by the Salmonella/mammalian microsome test. Frozen liver sections were stained for γ-glutamyl transpeptidase (GGT) activity. Only the 1000 ppm BAP treatment induced elevated blood plasma levels of AFP and GGT-positive hepatic cell foci. Urine from rats fed 1000 ppm BAP or 100 ppm BAP + 500 ppm PB caused a significant (P < .05) increase in revertants of S. typhimurium, compared to urine from control rats. Evidence from this investigation suggests that plasma AFP determination and urinary mutagenesis testing could be useful in short term ...