Influence of toluene co-exposure on the metabolism and genotoxicity of benzene in mice using continuous and intermittent exposures.

Benzene exposure in occupational settings often occurs with concurrent exposure to toluene, the methyl-substituted derivative of benzene. Toluene is also readily metabolized by CYP450 isozymes although oxidation primarily occurs in the methyl group. While earlier mouse studies addressing co-exposure to benzene and toluene at high concentrations demonstrated a reduction in benzene-induced genotoxicity, we have previously found, using an intermittent exposure regimen with lower concentrations of benzene (50 ppm) and toluene (100 ppm), that toluene enhances benzene-induced clastogenic or aneugenic bone marrow injury in male CD-1 mice with significantly increased CYP2E1, and depleted GSH and GSSG levels.

Application of process chemistry and SAR modelling to the evaluation of health findings of lower olefins.

Epidemiology studies show increased leukemia mortality among styrene butadiene rubber (SBR) workers but not among butadiene monomer production employees. A detailed review of the SBR manufacturing process indicates that sodium dimethyldithiocarbamate (DMDTC) introduced into the SBR manufacturing process for a period in the 1950s coincides with increased leukemia mortality. Using the Computer-Optimized Molecular Parametric Analysis of Chemical Toxicity (COMPACT), we assessed the enzyme (cytochrome P450) substrate specificity of an olefin series including 1,3-butadiene (BD) and also modeled its interaction with DMDTC.

Assessment in rats of the reproductive toxicity of gasoline from a gasoline vapor recovery unit.

Gasoline (CAS 86290-81-5) is one of the world's largest volume commercial products. Although numerous toxicology studies have been conducted, the potential for reproductive toxicity has not been directly assessed. Accordingly, a two-generation reproductive toxicity study in rats was conducted to provide base data for hazard assessment and risk characterization.

Toxicology of n-pentane (CAS no. 109-66-0).

n-Pentane (CAS no. 109-6-0) is a hydrocarbon solvent with an estimated production volume of 50000 metric tons in Europe. The present work was carried out to strengthen the toxicological information available for regulatory decision-making, particularly product classification, occupational exposure limits and risk assessment.

A clinical comparison of two bleaching systems.

Recent improvements in the in-office techniques for bleaching teeth have reduced chair time, simplified the procedure and reduced the potential for pulpal inflammation and other side effects. Home bleaching has become very popular, but many patients will still prefer the faster, in-office procedure done by their dentist. This comparison of two 35 percent hydrogen peroxide products confirms that these procedures are effective and should be a part of any practice providing esthetic improvements for its patients.

Sensory irritation response in mice to sulfur dust.

The potential of sulfur dust to produce sensory irritation was evaluated in mice. Male Swiss--Webster mice were exposed by head-only inhalation to 106, 263, or 451 mg/m3 sulfur dust aerosol at room temperature. Breathing frequency and patterns were monitored before, during, and after exposure to evaluate the animal's sensory irritation response to the test atmosphere.