Abs tract. We have reported previously that arginine-induced insulin secretion was impaired in the vitamin D-deficient rat pancreas, and that it was improved by dietary vitamin D repletion (Norman, A. W., B. J. Frankel, A. M. Heldt, and G. M. Grodsky, 1980, Science [Wash. DC]. 209:823-825). In this study, we evaluate in the perfused rat pancreas system whether the effects of vitamin D and its metabolites on insulin secretion are direct in action on the pancreas and limited to the secretagogue arginine, or whether they are secondary to the hypocalcemia or reduced caloric and calcium intake associated with vitamin D deficiency. In an experiment where vitamin D-replete (+D) rats were pair-fed to Ddeficient (-D) rats fed ad lib., the secretion of insulin in response to arginine infusion in the +D perfused rat pancreas was threefold higher than in the -D control. In a second experiment, the serum calcium level was elevated from the characteristic hypocalcemic level of -D rats (4.9±0.1 mg/dl) to a normal calcemic level (10.0±0.3 mg/dl) by feeding the rats a -D diet with dietary calcium levels ranging from 0.4 to 4%. In these -D rats, the pancreatic perfusion study with the secretagogue arginine showed a similar blunted insulin secretion response in all groups in spite of the significant differences of serum calcium levels. In a third experiment, insulin secretion in response to the separate administration of arginine (10 mM), glucose (16.9 mM), and tolbutamide (0.37 mM) was found to be significantly higher in pair-fed, normocalcemic +D rats than in -D rats with normal calcium

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TAZ/PIPC is as effective and safe as IPM/CS in the treatment of moderate- to-severe aspiration pneumonia.

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It has been demonstrated that the GM2 ganglioside cannot be cleaved by exo-beta-N-acetylhexosaminidases isolated from molds or bacterial sources. Here, a novel GM2 ganglioside-degrading enzyme was found in cells of Nocardia sp. This enzyme releases free fatty acids from the GM2 ganglioside. The chemical structure of the resultant lyso-GM2 ganglioside has been characterized by fast atom bombardment mass spectrometry, gas chromatography, and proton nuclear magnetic resonance spectroscopy. Using 14C-labeled GM2, at the fatty acid moiety, with stearic acid as the substrate, the optimum pH was determined to be 5.8. The enzyme was demonstrated to be capable of releasing fatty acids from GM3, GM2, GM1, and GD1a, and from neutral glycosphingolipids including Gb3-Cer, asialo-GM2, and asialo-GM1, but not from sphingolipids including Cer, Gal-Cer, Glc-Cer, and Lac-Cer. This enzyme, tentatively called glycosphingolipid ceramide deacylase, was found to be a tightly membrane-bound enzyme.