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Biomedical subjects

S Yamamura

Publications and source records attributed to S Yamamura.

12 recordsLinked to original sources
PubMed1977

Clinical significance of e-antigen/anti-e, with special reference to HBc-antigen in the liver.

e-antigen and anti-e were assayed in sera of asymptomatic HBs-Ag carriers and of patients with liver diseases. Thirteen out of 34 (38.2%) asymptomatic carriers were positive for e-antigen, which was in sharp contrast to the reports from USA and Europe. e-antigen was detected to a greater extent in patients with chronic active hepatitis, reversely anti-e in patients with chronic persistent hepatitis. However, e-antigen was found rarely in patients with cirrhosis and never in 23 cases with hepatoma positive for HBs-Ag. HBc-Ag in the liver was detected in 4 out of 8 e-antigen positive asymptomatic carriers and in 4 out of 5 patients with chronic liver diseases with e-antigen respectively, and moreover in 3 out of 14 anti-e positive cases, so that the presence of anti-e did not necessarily mean the negativity of HBc-Ag in the liver. Anti-HBc titer, however, was lower in anti-e positive sera than in e-antigen positive ones. This may implicate the decreased replication of HBV in cases with anti-e. These results emphasize that the investigation of e-antigen/anti-e is mandatory for the evaluation of the prognosis of asymptomatic carriers and of patients with chronic hepatitis.

Adult↗
PubMed1976

Studies on the structure activity relationship of adrenergic beta-mimetic benzylamine derivatives.

Appropriately substituted benzylamine (BZA) derivatives, fragmented derivatives of tetrahydroisoquinolines, were found to be directly acting adrenergic beta-stimulants, exhibiting tracheal relaxing, positive chronotropic and free fatty acid (FFA) releasing activities. The chemical structures essential for manifestation of the beta-action were i) 3,4-dihydroxybenzylamine, ii) arylmethyl group at position alpha, iii) lower alkyl group on the N atom. The structure activity relationships of BZA-derivatives were almost similar to, but partly different from those of tetrahydroisoquinoline- and catecholamine-derivatives. The tracheal relaxing, positive chronotropic and FFA-releasing actions of alpha-(3,4,5-trimethoxybenzyl)-N-methyl-3,4-dihydroxybenzylamine, the most active compound in the BZA-derivatives tested, were approximately one-hundred, thirty and fifty times less active than those of ISO, respectively. These results indicate that this compound is beta1-selective, while trimetoquinol is beta2-selective.

Adipose Tissue↗
PubMed1975

Studies on mode of antagonism between adrenergic beta-mimetics and beta-blocking agents (I). Beta-blocking action of mescaline and its derivatives.

In order to clarify whether or not trimetoquinol (TMQ) and isoproterenol (ISO) interact with the same receptor, the pA2 values of propranolol (PR) and certain trimethoxybenzene derivatives were measured, using isolated guinea pig tracheal chains. Each of PR, mescaline (MES) and its derivatives gave almost the same pA2 values for TMQ and ISO. Introduction of an alkyl group into the N atom of MES increased the affinity to the receptor in the order of methyl and isopropyl as well as the structureactivity relationship of catecholamines, while that of hydroxyl group in the beta-position of the side chain decreased pA2 values. The slopes of the regression lines for anti-TMQ action of MES derivatives as well as PR were almost one, but those for their anti-ISO action were less than 0.3. 3,4,5-Trimethoxyaniline and 3,4,5-trimethoxybenzoic acid had little activity as beta-blocking agents. These results suggest the possibility that TMQ and ISO would interact with the same receptor sites. The importance of the trimethoxybenzene and the phenethylamine moieties in the MES-derivatives for anti-TMQ action is discussed.

Adrenergic beta-Agonists↗