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Biomedical subjects

S P Bayard

Publications and source records attributed to S P Bayard.

5 recordsLinked to original sources
PubMed1990

Cancer risk assessment of 1,3-butadiene.

This paper discusses the Environmental Protection Agency's (EPA) risk assessment of 1,3-butadiene. The assessment focuses on estimation of increased cancer risk to populations living near industrial sources of 1,3-butadiene emissions rather than occupationally exposed populations. Incremental cancer risk estimates based on extrapolation from laboratory animal data are presented. Pharmacokinetic data published since the EPA's 1985 assessment are incorporated, which somewhat alters the earlier assessment of cancer risk. Characterization of emission sources, estimates of ambient air concentrations, and population exposure are also discussed. The estimate presented in this paper of excess cancer cases resulting from point source exposure to 1,3-butadiene is decreased to approximately 40% of the estimate published in 1985 from 6.4 in 10 to 2.5 chances in 10 for a lifetime exposure to 1 ppm. The current estimate is no more than eight additional cancer incidences in the general population. Increased risk to the most exposed individuals is not anticipated to be greater than 1 in 10. This reduction in the risk estimate is due to a change in the estimate of 1,3-butadiene potency (i.e., incremental unit risk estimate) based on incorporation of new pharmacokinetic data.

Air Pollutants↗
PubMed1977

Detergent toxicity survey.

A survey of over 249 detergent products involving biological testing, chemical analyses, and product label reviews has been conducted from 1971-1976 for determining compliance with the Federal Hazardous Substances Act. Test results for 145 detergent products having both chemical and biological data were examined. All of the tested detergents were rabbit eye irritants. Forty-seven per cent were also either rabbit primary skin irritants or corrosives. Eighty-one per cent were either rabbit esophageal test irritants or corrosives, and 80 per cent had rat oral toxicities 5g/kg or less.

Animals↗
PubMed1976

Appraisal of existing methodology in aspiration toxicity testing.

New methods or modifications of currently used methods in aspiration toxicology must be capable of accurately assessing the hazard and toxicity potentials of those products which are capable of being aspirated. The methods evaluated in the rat were intratracheal injections,intravenous injections, and modifications of the Gerarde technique. A product containing petroleum distillates and a standard viscosity petroleum distillate sample were administered to Osborne-Mendel rats, rabbits, and guinea pigs in ml/kg doses. The utility of the methods was determined by comparing lung weight increases, lung-body weight ratios, gross pathological lung changes, and mortality. The modified Gerarde technique showed the best potential for predicting aspiration hazard and toxicity based on the severity of the reactions which, using a radiolabeled oil, was shown to be a function of the amount of product which enters and reacts with the lungs. The influence of preventing the swallowing reflex to assure aspiration of the oil was assessed in the rat. The results show that less than 10% of the dose is aspirated when the swallowing reflex occurs. Methods of sacrifice were investigated for an effect on rat lung weight. No tested method except stunning with cervical dislocation produced an effect. Tests were conducted on rats and rabbits to determine differences in lung reactivity to the influence of inhalation anesthetics, pentothal sodium, or no anesthesia in response to petroleum distillate administration and to determine which test species is the better animal model. The resuls indicate that the rat is the better test model because of degree of lung reaction, size, and economy, and that inhalation anesthesia with ether is preferable over the other choices.

Animals↗