Backfat was obtained at slaughter from market weight hogs to study the acute effects of clenbuterol (CB), ractopamine (RAC) or epinephrine (EPI), in the presence and absence of theophylline (THEO) or adenosine deaminase (ADA), on rates of lipolysis and fatty acid synthesis in vitro. Only EPI increased lipolytic rate in the absence of THEO or ADA. In the presence of THEO or ADA, RAC and CB were lipolytic, although CB had a lower maximal response. With THEO present, RAC and EPI increased lipolysis with a similar potency and responsiveness. Lipolytic responses from all agonists were prevented by propranolol. Insulin stimulated glucose incorporation into fatty acids 50 to 100%; stimulated rates were not influenced by any agonist, either alone or in the presence of ADA. When THEO was present, EPI and RAC inhibited fatty acid synthesis approximately 50%. Clenbuterol was not inhibitory under any conditions. Results indicate that, under appropriate conditions, beta-adrenergic agents increase lipolysis and decrease lipogenesis in porcine adipocytes. Combined evidence suggests that lipolysis is more sensitive to beta-adrenergic stimulation than is insulin-stimulated lipogenesis. Finally, RAC and CB possess only partial agonist activity relative to EPI, CB being least active.
Chronic ischemic gastritis is an unusual entity that is rarely distinguished from other forms of intestinal ischemia. On the basis of a case encountered and a subsequent review of the literature, the main features of this rare condition are described here. A better understanding and awareness of the disease should improve the diagnosis and ultimately also the prognosis.
A chemical shift analysis of the 13C NMR spectra of more than 50 acyclic sulphonic acids, alkali metal sulphonates and methyl esters was carried out. Chemical shift increment systems with n-alkanes as reference molecules were established for linear alkanesulphonates and alk-2-enesulphonates. Some shortchain fluorinated sulphonic acids were also studied, especially pentafluorothio derivatives. C-F spin-spin coupling constants were determined. Pauling electronegativity values for SO,H and SF, groups were derived from a chemical shift increments.
The "C NMR spectra of 20 compounds belonging to several types of monocyclic sultones and related 'carbyl sulphates,' including a series of fluorinated 8-sultones(1,2-0xathietane 2,2-dioxides), are reported. Chemical shift increment systems with n-alkanes a s reference molecules are established for non-fluorinated sultones: they show a much less pronounced deshielding effect on the carbon a to oxygen in /3-sultones than in the other series. Chemical shifts for the parent 8-sultone, predicted in two ways (linear or cyclic model compound), are found to be almost consistent with a purely additive scheme. In fluorinated 8-sultones the asubstituent increments relative t o perfluoroethanesultone are also derived.
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