Burde L. Kamath

Bioaccumulation of chromium in red swamp crayfish (Procambarus clarkii)

Abstract Crayfish were exposed to a range of potassium dichromate concentrations (0.15, 0.30, 3.0 and 30 mg l−1) for periods up to 7 weeks. Chromium bioaccumulation in all tissues over the 7 week exposure period was not consistently time- and dose-dependent. The order of distribution of chromium into the various tissues was dependent upon the exposure concentration of the metal. Chromium clearance studies conducted 1 and 3 weeks following exposure demonstrated a concentration reduction in most tissues only at the highest exposure concentration of chromium (30 mg l−1). Histological studies demonstrated damage to both the gills and hepatopancreas at the lowest exposure concentration. The results suggest that the red swamp crayfish, Procambarus clarkii, is a useful biomarker for chromium exposure.

Disposition study of procainamide and N-acetylprocainamide during subacute administration in rats.

Abstract The purpose of this investigation was to study the disposition of procainamide (PA) and N-acetylprocainamide (NAPA) during repeated administration to male and female Charles River CD rats. Both drugs were administered in the diet for 8 weeks at doses of (320, 1280, and 2560 mg/kg/day). Plasma and urine samples were collected from each animal after 2 and 8 weeks of dosing for up to 48 hr. PA and NAPA concentrations in plasma and urine samples were determined by specific high-pressure liquid chromatographic methods. The plasma concentration-versustime profile showed highest plasma concentrations at midnight and lowest concentrations at 6 pm , suggesting that food consumption was greatest between 6 pm and midnight. On the average, 16 and 51% of the estimated doses of PA and NAPA, respectively, were excreted unchanged in urine in both sexes. In the animals which received PA, the ratio of unchanged drug excreted in urine to its acetylated form, i.e., NAPA, increased with an increase in the dose, suggesting saturation of the acetylation process and confirming the dose-dependent kinetics of PA elimination in rats. Within the dose range administered in this study, the elimination kinetics of NAPA was linear. The results of this work showed that PA and NAPA toxicity studies could be conducted by dietary administration.