Motonori Fujiwara

Anti-hypercholesterolemic effect of a sulfur containing amino acid, S-methyl-l-cysteine sulfoxide, isolated from cabbage

Die Antihypercholesterinwirkung der aus dem Kohl isolierten S-Methylcysteinsulfoxide (SMCS) wurde untersucht. Bei Ratten mit experimentell induzierter Hypercholesterinämie kam es zu einem Abfall der Cholesterinwerte im Blut und in der Leber.

Effect of capsaicin on the guinea-pig isolated atrium

tyramine given by other workers would not have interfered with the lipolytic action of the endogenous noradrenaline it released, because the lipolytic action of tyramine caused by it releasing noradrenaline is apparent at concentrations lower than those at which tyramine modifies its response to added noradrenaline. This work was supported by Research Grant from U.S. Public Health Service (HE 11848).

Interrelationship between Ca2+-dependent phospholipid base-exchange reaction and phospholipase D-like activity in bovine retina

Endogenous substrates (phosphatidylserine, phosphatidylethanolamine and phosphatidylcholine) for the Ca2+-dependent base-exchange reaction were investigated using bovine retinal microsomes. The amounts of the three bases, serine, ethanolamine and choline, released from the membranes and the amount of phosphatidic acid generated in the membranes were measured in the presence of Ca2+ with or without exogenous bases. When the membranes were incubated with Ca2+ alone, the three bases were liberated into the water-soluble fractions accompanied by accumulation of phosphatidic acid, suggesting the presence of Ca2+-dependent phospholipase D-like activity. When an exogenous base was added to the reaction mixture, the liberation of the other two bases increased slightly and the formation of phosphatidic acid decreased markedly. The exogenous base also stimulated the liberation of the same base from prelabeled phospholipids. Accompanying these changes, the exogenous base was incorporated into the membrane phospholipid. With respect to pH profile, time course and metal requirements, both the base incorporation and phospholipase D-like activity were quite similar. The amount of base incorporated generally agreed with both the decreased amount of phosphatidic acid formed and the increased amount of base released. These results suggest that, beside the base-exchange reaction, phospholipase D-like activity plays an important role in Ca2+-dependent base incorporation into bovine retinal membranes.

The differential determination of benzoylthiamine and thiamine in biological materials

Abstract Many thiamine derivatives containing a benzoyl group on the thiazole ring have been synthesized recently. These compounds are being used clinically in a variety of disorders thought to be thiamine-related, because they are more readily absorbed than thiamine (1–9). Several authors have suggested the possibility that benzoylthiamine might be formed in animal tissues after administration of these drugs (10–15). Because of the difficulty of separation or differential determination of benzoythiamine and thiamine, the formation of this compound in animal tissues after the administration of precursors has not been completely clarified. Since benzoylthiaminc is strongly toxic to animals (16), investigation of its biosynthesis may be clinically important. The usual fluorometric method for the determination of thiamine (17) cannot differentiate between benzoylthiamine and thiamine because cyanogen bromide in sodium hydroxide converts both compounds to thiochrome (4). In this report we represent a modification which permits a differential determination of the two compounds.

Relationship between Thiamine and Ethanol Intake

Recently, the relationship between thiamine and ethanol intake has drawn public attention, because alcoholism is often accompanied by thiamine deficiency. The possible mechanisms involved in thiamine deficiency may be summarized as follows: 1. Low intake of thiamine in alcoholic patients. 2. Absorption of thiamine from gut is impaired by ethanol administration. 3. Impairment of thiamine retention in the body by ethanol administration.

The transport mechanism of thiamine propyl disulfide into human blood cell membrane

Thiamine propyl disulfide (TPD), a lipotropic derivative related to thiamine, has a specific ability to cross the biological membrane. In the present paper the mechanism of reduction and uptake of TPD in blood is described. TPD is converted to thiamine by a heat stable factor(s) in blood cells and to a slight extent by plasma. This reducing ability of blood cells is increased with the aid of plasma. From the fact that this conversion is inhibited by p-chloromercuribenzoic acid, it is postulated that SH groups may play a major role in this reduction process. A possible explanation on the mechanism for accumulation of TPD in blood cells is presented.