[Effect of thiamine phosphates on the activity of regulatory enzymes of the pyruvate dehydrogenase complex]. / Vliianie tiaminfosfatov na aktivnost' reguliatornykh fermentov piruvatdegidrogenaznogo kompleksa.

The effect of thiamine triphosphate (ThTP) and thiamine diphosphate (ThDP) on the activity of rat liver pyruvate dehydrogenase complex regulatory enzymes (kinase and phosphatase) was studied in experiments with isolated enzyme preparations. It is shown that ThDP caused a pronounced activation of pyruvate dehydrogenase phosphatase (Ka is equal to 65.0 nM). ThTP inhibits phosphatase competitively against the substrate--the phosphorylated pyruvate dehydrogenase complex. The both thiamine phosphates inhibit the pyruvate dehydrogenase kinase activity almost similarly in concentrations exceeding 10 microM. The physiological significance of the antagonistic action of ThDP and ThTP on the pyruvate dehydrogenase phosphatase activity is discussed.

[Biochemical investigation of patients with jaundice of tumor genesis]. / Biokhimicheskoe issledovanie u bol'nykh s mekhanicheskoi zheltukhoi opukholevogo geneza.

The study comprised surgical patients presenting with tumours of the extrahepatic biliferous ducts. The above patients revealed a high activity of gamma-glutamyltransferase, alkaline phosphatase at the expense of the hepatic isoenzye, to a lesser extent--of asparaginaminotransferase, alaninaminotransferase, a high level of conjugated bilirubin, an insignificant increase in the level of cholesterol and triglycerides. The above biochemical indices combined with results of other methods of investigation can be used for early diagnosis of mechanical jaundice of the tumour genesis.

[Regulatory role of duodenal evacuation activity in determination of the absorption rate of organic components of duodenal chyme]. / Regulatornaia rol' évakuatornoi aktivnosti dvenadtsatiperstnoi kishki v opredelenii tempa vsasyvaniia organicheskikh komponentov duodenal'nogo khimusa.

The effect of inhibited duodenal motor-evacuation on the rate of protein, glucose, and lipid absorption was studied in chronic experiments in 5 polyfistulous dogs. Evacuation was inhibited by division of Treitz's ligament (a model of duodenostasis). The results of the experiments are evidence of a considerable regulatory effect of chyme evacuation rate on the value of the flow of substances from the enteral medium into the blood. The evacuation rate is in inverse proportion to the adsorption rate.

[Interaction of thiamine with rat brain synaptosomes]. / Vzaimodeistvie tiamina s sinaptosomami mozga krys.

Thiamine has been shown to be bound specifically by a synaptosomal plasmatic membrane and transported inside to the nervous ending. Apparent K[symbol: see text] and Km for processes of binding and transport have been determined as equal 2.34 +/- 0.55 MKM and 3.92 +/- 1.3 MKM, respectively. The thiamine uptake by the isolated nervous endings (synaptosomes) at its physiological concentration is reduced in presence of metabolic inhibitors and partially depends on Mg2+ and Ca2+ ions, that can testify about the interrelation between endogenic thiamine phosphorilation and its transport through the membrane. Thiamine binding with synaptosomes is inhibited by ouabain and neurotoxins such as, latrotoxin and most significantly--with veratridin; tetrodotoxin fail to be efficient practically. In the conditions of synaptic membranes depolarisation their ability to bind thiamine is reduced and output of already uptaken with synaptosomes thiamine is observed.