Journal of toxicology and environmental health
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J Toxicol Environ Health · Apr 1983
Comparative StudyEstimated intakes of pyrrolizidine alkaloids by humans. A comparison with dose rates causing tumors in rats.
Pyrrolizidine alkaloid poisoning in humans is associated with the consumption of plants containing the alkaloids, either as contaminants of grains or as infusions for medicinal purposes. The alkaloids are carcinogenic in rats but have not been associated, so far, with tumors in humans. ⋯ In the more chronic poisoning outbreaks, the intake rate is comparable with a carcinogenic dose in rats. The long-term observation of survivors of these outbreaks would offer an opportunity for determining whether pyrrolizidine alkaloids are carcinogenic in humans.
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J Toxicol Environ Health · Jul 1981
Effects of sulfuric acid and nitrogen dioxide on airway responsiveness of the guinea pig.
Hartley guinea pigs were exposed for 1 h to either NO2 gas of H2SO4 aerosol and examined for changes in airway responsiveness to inhaled histamine. Concentrations ranged from 7 to 146 ppm NO2 and 4 to 40 mg/m3 H2SO4. One group of animals exposed to filtered air served as controls. ⋯ Some animals exposed to H2SO4 developed severe labored breathing during exposure, and major increases in histamine sensitivity were observed only in those animals. These results suggest that both No2 and H2SO4 alter airway sensitivity to histamine, but apparently by different mechanisms. Changes produced by NO2 exposures appeared primarily concentration-dependent, while changes produced by H2SO4 exposures appeared related to dyspnea developed during exposure.
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J Toxicol Environ Health · Mar 1981
Estimating the hazards of less hazardous cigarettes. II. Study of cigarette yields of nicotine, carbon monoxide, and hydrogen cyanide in relation to levels of cotinine, carboxyhemoglobin, and thiocyanate in smokers.
Yields of chemical constituents such as tar, nicotine, CO, and HCN defined by smoking machines are commonly assumed to provide a reasonable indication of the relative hazard associated with smoking a given brand of cigarette. Results reported here suggest that this assumption should be carefully reexamined. ⋯ In addition, a comparison of levels of carboxyhemoglobin and plasma thiocyanate for 16 smokers of "low-hazard" and 15 smokers of "high-hazard" cigarette brands revealed little difference between the two groups, even though average cigarette yields differed as much as 2- to 3-fold. A possible explanation for the results may be that current values for average puff volume, duration, and interval differ significantly from those used in programming smoking machines, particularly in the case of brands with low nicotine delivery.
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J Toxicol Environ Health · Mar 1981
Effects of sulfuric acid aerosols on pulmonary function of guinea pigs.
Forty-seven Hartley guinea pigs were exposed for 1 h to approximately 1-micrometer (mass median aerodynamic diameter) sulfuric acid aerosols at concentrations that ranged from 1.2 to 48.3 mg/m3. Ten animals (controls) were exposed to filtered room air only. Eight H2SO4-exposed animals exhibited marked increases in total pulmonary resistance and marked decreases in dynamic compliance. ⋯ Compared to nonresponders, responsive animals had higher preexposure values of tidal transpulmonary pressure excursions and total pulmonary resistance and lower values of dynamic compliance. Preexposure transpulmonary pressure excursions were positively correlated with minute volume only for nonresponsive animals; transpulmonary pressure excursions were positively correlated with total pulmonary resistance in responsive animals. The results suggest that the Hartley guinea pig reacts to inhaled H2SO4 with an essentially all-or-none airway constrictive response and that an animal's sensitivity to this response may be related to its preexposure airway caliber.
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J Toxicol Environ Health · Feb 1981
Effect of penicillic acid on biliary excretion of indocyanine green in the mouse and rat.
Penicillic acid (PA), a mycotoxin, is hepatotoxic. A study was undertaken to investigate its effects on hepatobiliary excretory function, using the anionic compounds indocyanine green (ICG), in mice and rats. Pretreatment with a single dose of PA (90 mg/kg, ip, an LD50 dose in both species) resulted in depression of ICG excretion in both species. ⋯ While the serum ICG concentration was increased after PA treatment in both species, the liver ICG concentration was not affected. The liver-to-serum, bile-to-serum, and bile-to-liver ICG concentration ratios decreased in PA-treated animals. These data suggest that the PA-induced hepatobiliary excretory dysfunction may result from depression of both uptake of ICG into the liver and bile canlicular transport of ICG.