Y. Lacasse

Influence of removal from occupational lead exposure on blood and saliva lead concentrations

Samples of total blood and unstimulated mixed saliva were obtained from 5 male workers occupationally exposed to lead at various time intervals after removal from their work environment. Initial blood lead concentrations were elevated in all workers and then slowly decreased upon removal. Lead concentrations in saliva fell much more abruptly than those in blood, the saliva half-lives being estimated at 5-7 days. Temporary return to work in 2 workers resulted in relatively marked increases of salivary lead concentrations. These results suggest that salivary lead is closely related to recent lead exposure.

Presence of cadmium in the saliva of adult male workers

Samples of mixed saliva were collected from 16 workers exposed to cadmium dusts and fumes and 19 unexposed co-workers. Samples of total blood and plasma were also obtained. Cadmium (Cd) was measured by flameless atomic absorption spectrometry. Cd was found in higher concentrations in saliva than in blood. The concentration of Cd in saliva was markedly elevated in exposed subjects; the difference was less important in blood. Smokers had more Cd in their blood than non-smokers, but this was not the case for saliva. In vitro studies measuring uptake of Cd by slices of rat submaxillary gland indicated that movement of the metal occurs passively.

Effect of an Acute Dose of Alcohol on the Pharmacokinetics of Oral Nifedipine in Humans

Pharmacokinetic and pharmacodynamic interactions of alcohol and nifedipine were assessed in 10 healthy human volunteers. Doses of 20 mg (2 × 10-mg capsules) of nifedipine were administered with either 150 ml of orange juice or 75 ml of alcohol (94%) in 75 ml of orange juice according to a crossover randomized design. Plasma nifedipine levels were monitored for 16 hr after each dosing, along with pulse rate and blood pressure. The relative bioavailability of nifedipine, measured as AUC, was increased by 54% (533 vs 346 ng · hr/ml) after the dose of alcohol (P < 0.0002). However, there were no significant differences between treatments in Cmax,tmax, or t1/2. Although there was no difference in the systolic and diastolic blood pressure and pulse rate between the two treatment groups, the time to reach peak heart rate was significantly faster in the group treated with alcohol (1.4 vs 2.2 hr). This study shows that ethanol increases the bioavailability of nifedipine and decreases the time for onset of increased heart rate.