No abstract

To understand nutritional rickets in Bangladesh better, 14 rachitic and 13 'unaffected' children were evaluated. Seventy per cent of children with active rickets had no evidence of either vitamin D deficiency or familial rickets. Rickets in Bangladesh is probably related to calcium deficiency. Abnormalities in 'unaffected' children suggest that subclinical calcium insufficiency is common.

Bupropion provided a dose-dependent prevention of tetrabenazine-induced sedation in mice but not rats. Bupropion was extensively metabolized in mice, rats, dogs and man. About 85% of the dose was excreted in urine of rats and man. The predominant metabolites in rat urine were side chain cleavage products of bupropion (m-chlorobenzoic acid) with a minor fraction consisting of basic side chain hydroxylated metabolites. Mice, dogs and man form a major side chain hydroxylated product (BW 306U) which appeared in higher concentration than bupropion in plasma of these species but not rats. The relatively high plasma levels of BW 306U in mice but not rats may account for the species difference in pharmacological response observed with bupropion.

The enzymatic hydroxylation of 3,4-benzpyrene was not detected in human placentas obtained after childbirth from nonsmokers, whereas this enzyme activity was present in placentas obtained from individuals who smoked cigarettes. The degree of induction of benzpyrene hydroxylase caused by cigarette smoking varied in different individuals. Treatment of pregnant rats with benzpyrene increased the activity of this hydroxylase in the placenta.

In human plasma the rate-limiting step in the degradation of cisatracurium is Hofmann elimination, with the initial formation of a monoquaternary acrylate. The observation that the monoquaternary alcohol results from ester hydrolysis of the monoquaternary acrylate by plasma esterase(s) explains the presence of the monoquaternary alcohol metabolite in human plasma during clinical studies with cisatracurium. The rapid hydrolysis of cisatracurium by rat plasma relative to human indicates a major species difference in plasma esterase(s).