Sensory irritation of select experimental photochemical oxidants.

Groups of male Swiss-Webster mice were exposed to photochemical oxidant mixtures generated by reacting various hydrocarbons with nitrogen dioxide in the presence of ultraviolet light while their respiratory rates were monitored. The hydrocarbons used were 1,3-butadiene, 1-butene, cis-2-butene, ethylene, propylene, n-butane, and ethane. The initial hydrocarbon concentrations ranged from .4 to 18 ppm, with the initial nitrogen dioxide concentration being one-third that of the initial hydrocarbon concentration. New groups (four mice per group) were exposed for 5 min at 0, 1, 2, 3, and 4 hr of ultraviolet irradiation. Dose-response curves for each hydrocarbon were developed by plotting the maximum percent decrease in respiratory rate observed during the 4 hr of irradiation of each mixture as a function of the initial hydrocarbon concentration present. The percent decrease in respiratory rate in mice was chosen as an index of the sensory irritation of the upper respiratory tract for each mixture. The results showed that the potency of the photochemical oxidant mixtures generated from the hydrocarbons to be propylene greater than 1,3,-butadiene = 1-butene=cis-2-butene greater than ethylene. When ethane or n-butane was used, no decrease in respiratory rate was observed. These results are compatible with the data obtained in human volunteer studies. Guidelines for relating the percent decrease in respiratory rate in mice to human reactions are presented.

Evaluation of sensory irritation from acrolein-formaldehyde mixtures.

Groups of mice were exposed to eleven combinations of acrolein-formaldehyde atmospheres and their respiratory rate was monitored. A mathematical model, previously derived for analysis of taste receptor stimulation, was applied to the data obtained for each of the above chemicals alone and in combination. The results obtained suggest that such a model adequately described sensory irritation due to these chemicals and indicates that competitive agonism exists between acrolein and formaldehyde when present together.

Sensory irritation to formaldehyde and acrolein during single and repeated exposures in mice.

Mice were exposed to various concentrations of formaldehyde or acrolein. Concentration-response relationships were developed by measuring per cent decrease in respiratory rate, indicating upper respiratory tract sensory irritation. Relationships are presented between the concentration associated with a 50% respiratory decrease and TLVs. A summary of other animal inhalation studies is presented. The basis for the acrolein and formaldehyde TLVs are reviewed. Mice exposed for 4 days showed increasing sensitivity daily for both compounds. A re-evaluation of the TLVs is suggested.

A short-term test to predict acceptable levels of exposure to airborne sensory irritants.

An animal model has been developed using decrease in respiratory rate in mice as an index of sensory irritation. Concentration-response relationships were developed for 11 sensory irritants. The RD50, defined as the concentration associated with a 50% decrease in respiratory rate, has been shown to have a predictable relationship to sensory irritation in man. By extending the accepted toxicological principle that the ratio lethal/toxic/effective/ineffective/acceptable in diet is 10/1/10(-1)/10(-2)/10(-3) dosage units to air concentrations, exposure guidelines can be proposed for TLVs, STELs, etc.

Evaluation of sensory irritation from some common industrial solvents.

An animal bioassay model was used to determine the potency of some common industrial solvents as sensory irritants. Acetone was found to be the least potent and ethyl acetate the most potent. A series of alcohols tested, from methanol to pentanol, revealed an increase in potency with the increasing number of carbons.

Cost comparison of intraoperative autologous versus homologous transfusion.

The cost of autologous transfusions using semiautomated instruments in 52 orthopedic cases, 75 coronary artery bypass graft (CABG) cases, and 218 aortic aneurysm cases was compared to the cost of equal amounts of homologous blood. While none of the orthopedic cases reached cost equivalence (median cost deficit per case, +97), 31 percent of the CABG cases (median cost deficit per case, +61) and 56 percent of the thoracic aortic aneurysm cases (mean cost surplus per case, +30) did so. In most cases, the major orthopedic and CABG procedures do not reach cost equivalence and might be served better by other means of autologous blood recovery. The more expensive semicontinuous flow devices are more cost-effective for higher-yield cases, such as major aortic aneurysm procedures.