Long-term variation study of blood plasma levels of chloroform and related purgeable compounds.

Values for circulating plasma chloroform of 25 white adult females were monitored for 6 months during the first phase of a four-phase long-term variation study. The data suggested four major exposure categories. Category I (20%) had average chloroform levels less than 10 ppb and variation ranges less than or equal to 10 ppb. Category II (24%) had average levels of 10-25 ppb and ranges of less than or equal to 10 ppb. Category III (20%) had average levels of 10-25 ppb and ranges greater than 20 ppb. Category IV (28%) had average chloroform levels of greater than 25 ppb and variation ranges greater than 20 ppb. Although the participants had been carefully screened to exclude incidents of occupational and recreational exposure, three subjects in category IV experienced obvious incidences of acute exposure to either chloroform or a chloroform precursor. In these situations circulating plasma chloroform levels were between 1655 ppb and 4000 ppb.

Distribution of volatile halogenated organic compounds between rat blood serum and adipose tissue.

A 31-day rat-dosing sequence was used to study some aspects of the physiological distribution, metabolism, storage and rate of elimination of chloroform, trichloroethylene, carbon tetrachloride and bromodichloromethane from rat adipose tissue and blood serum. Data points were collected nine times during the dosing period and twice after dosing had ceased. Purge/trap/desorb methodology was employed using a liquid sample concentrator, a gas-liquid chromatograph and a Hall electrolytic conductivity detector in series. Compound identities were confirmed using a GC/MS analytical system. For these volatile compounds, tissue levels fluctuated but did not indicate increased storage with time. Adipose tissue to blood serum levels never differed by more than a factor of three. Within 3-6 days after dosing was terminated, practically all of the halogenated compounds had left the examined tissues. Metabolic conversion of trichloroethylene and carbon tetrachloride into chloroform and/or a chloroform precursor was observed; bromodichloromethane-dosed animals did not have serum chloroform levels exceeding those observed for the control animals.

Effects of diphenylhydantoin and chloroquine on monkey liver microsomal mixed-function oxidases.

Sixteen adult male squirrel monkeys (Saimiri sciureus) were randomly divided into three treatment groups and one control group. Each treatment group received 10 mg/kg oral doses of diphenylhydantoin and/or chloroquine. Following sacrifice, in vitro assays for activity of liver microsomal mixed-function oxidases were run. The assays confirmed diphenylhydantoin as a potent inducer of mixed-function oxidases. Chloroquine administration had little affect on the enzymes assayed and did not inhibit the diphenylhydantoin induction.