Carcinogenesis
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It has been assumed for some time that the 'tar' and nicotine data for individual cigarette brands, as reported by the Federal Trade Commission (FTC), do not adequately reflect the levels of exposure to toxic and carcinogenic agents in the smoke. The trend of decreasing 'tar' and nicotine yields of the sales-weighted average US cigarettes was not followed by a proportionate decline of lung cancer incidence and mortality rates. Utilizing a 'tobacco smoke inhalation testing system', we determined smoking profiles for four men and four women who smoked low-nicotine cigarettes ( < or = 0.8 mg/cigarette according to FTC), and for two men and two women who smoked cigarettes with medium-nicotine (0.9-1.2 mg) yields. ⋯ Significant increases in terms of total volume of smoke inhaled and exposures to 'tar', nicotine, and lung carcinogens were measured (2- to 4-fold) and, because of smokers' compensation for low nicotine delivery, much greater overall exposure resulted from smoking low-nicotine cigarettes. Although these measurements were obtained for a limited number of smokers, they strongly indicate that both low- and medium-nicotine cigarettes are being smoked much more intensely than would be implied from the FTC-data. Therefore, there is an urgent need to accurately quantify the exposure of consumers of the various types of cigarettes to toxic and carcinogenic agents.
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Randomized Controlled Trial Clinical Trial
Effects of consumption of Brussels sprouts on intestinal and lymphocytic glutathione S-transferases in humans.
A high intake of glucosinolate-containing cruciferous vegetables, such as Brussels sprouts (Brassica oleraceae), has been linked to a decreased cancer risk, but the underlying mechanism is still unclear. The aim of this study was to reveal possible modulating effects of consumption of Brussels sprouts on duodenal, rectal and lymphocytic (i) glutathione S-transferase (GST) enzyme activity, (ii) GST isozyme levels and (iii) glutathione (GSH) content. Ten healthy non-smoking volunteers were randomly assigned to two groups in a cross-over design. ⋯ GSH contents were uninfluenced by the dietary regimen. In conclusion, consumption of glucosinolate-containing Brussels sprouts for 1 week results in increased rectal GST-alpha and -pi isozyme levels. We hypothesize that these enhanced detoxification enzyme levels may partly explain the epidemiological association between a high intake of glucosinolates (cruciferous vegetables) and a decreased risk of colorectal cancer.