[Trans-muconic (t,t-MA) and S-phenilmercapturic acid: two biologic markers of benzene low dose exposure]. / Acido trans-trans-muconico (t,t-MA) e acido S-fenilmercapturico (S-PMA) due indicatori biologici per esposizioni a basse concentrazioni di benzene.

The aim of our study is the comparison between two different biological exposure index, trans-trans-muconic acid (t,t-MA) and S-phenylmercapturic acid (S-PMA), that are minor metabolites of benzene, in the exposure to low concentrations of benzene, to estimate which shows better correlation with the environmental exposure. The study has been conducted upon a sample of 105 male workers in a petrolchemical plant in Sicily. The environmental monitoring data has shown exposure levels within acceptable limits compared with TLV, and these levels have been confirmed by biological monitoring data. The comparison between biomarkers didn't point out particular differences and this data is probably connected to low found levels of exposure.

Hemodynamic and humoral interactions between captopril and nifedipine.

Nine patients with uncomplicated essential hypertension received, according to a randomized sequence, captopril (25 mg three times daily), nifedipine (10 mg three times daily), and both drugs for 1 week, with each treatment period separated by a 1-week interval during which a placebo was given. Captopril significantly reduced blood pressure and plasma aldosterone, increased plasma renin activity (PRA), and did not change heart rate. Nifedipine exerted a similar effect on blood pressure and PRA, but it increased heart rate and did not change aldosterone. Captopril plus nifedipine further reduced blood pressure and increased PRA, did not change heart rate, and reduced aldosterone to values similar to those after captopril alone. The hypotensive effect of captopril was highly predictable by basal PRA values, and that of nifedipine by age, while PRA increments induced by captopril were unrelated to those induced by nifedipine. These data indicate that: 1) captopril and nifedipine exert an additive effect on blood pressure and renin; 2) captopril counteracts the heart rate increase induced by nifedipine; 3) nifedipine does not influence the aldosterone inhibition induced by captopril. It is suggested that the association of the two drugs can be usefully employed in the treatment of hypertension.