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Biomedical subjects

T Tezuka

Publications and source records attributed to T Tezuka.

At least 163 records · Page 9Linked to original sources
PubMed1984

Selective inhibition of thrombin by (2R,4R)-4-methyl-1-[N2-[(3-methyl-1,2,3,4-tetrahydro-8-quinolinyl++ +) sulfonyl]-l-arginyl)]-2-piperidinecarboxylic acid.

The potency of thrombin inhibition by 4-methyl-1-[N2-[(3-methyl-1,2,3,4-tetrahydro-8-quinolinyl)-sulfony l]- L-arginyl]-2-piperidinecarboxylic acid (MQPA) depended on the stereoconformation of the 2-piperidinecarboxylic acid moiety. Ki values for bovine alpha-thrombin were 0.019 microM with (2R,4R)-MQPA, 0.24 microM with (2R,4S)-MQPA, 1.9 microM with (2S,4R)-MQPA, and 280 microM with (2S,4S)-MQPA. (2R,4R)-MQPA of the four stereoisomers of MQPA was also the most potent inhibitor for other trypsin-like serine proteases with Ki values of 5.0 microM for trypsin, 210 microM for factor Xa, 800 microM for plasmin, and 1500 microM for plasma kallikrein. Examination of the potency of thrombin inhibition by arginine derivatives related to MQPA in structure suggested the presence of a specific binding site for the carboxamide portion (C-terminal side). The relative inhibitory potency of the four stereoisomers of MQPA for trypsin was nearly identical with that for thrombin, suggesting that the specific binding site for the carboxamide portion is present in both enzymes. Modification of thrombin by phosphopyridoxylation or the presence of heparin did not significantly alter the binding of MQPA.

Animals↗
PubMed1984

Viscometric and electron microscopic analysis of effects of griseofulvin and its derivatives on in vitro polymerization of microtubule proteins and depolymerization of microtubules.

Griseofulvin and its sixteen derivatives were investigated by viscometry to examine their effects on in vitro polymerization and aggregation of microtubule proteins and depolymerization of microtubules. Of these compounds, eight pairs of enantiomers were compared in their activities. Electron microscopic studies were performed in several samples. The results indicate that in the C ring moiety of griseofulvin derivatives natural (+)-griseofulvin structure is essential to show their functions on microtubule proteins and microtubules.

Animals↗
PubMed1984

2 Cases of hereditary palmoplantar keratoderma. An abnormality of keratohyalin granules and keratin fibril formation.

2 cases of hereditary palmoplantar keratoderma (Unna-Thost type and keratosis palmoplantaris striata s. linearis type) are reported. In the former, moderate hyperkeratosis and a partial decrease in the stratum granulosum were histologically seen. Keratohyalin granules in the uppermost cell layer of the stratum granulosum were positively stained with the Pauly reagent, though the stratum granulosum consisted of three of four cell layers in the hematoxylin-eosin-stained specimen. Electron microscopically, keratohyalin granules in the lower two or three cell layers of the stratum granulosum were less electron-dense than normal and were granular in appearance, but those in the uppermost cell layer were normal in electron density and in appearance. This case indicates that human keratohyalin granules could consist of a less electron-dense component and an electron-dense amorphous component, and the Pauly-positive substance could be electron-dense and amorphous, and the basophilic material in the hematoxylin-eosin specimen could be less electron-dense and granular under electron microscopy. In the latter, remarkable orthokeratotic hyperkeratosis and hypergranulosis were observed. Electron microscopically, three kinds of keratohyalin-like granules were observed: (1) less electron-dense granules, the electron density of which was equivalent to that of the peripheral region of the nucleus; (2) normally electron-dense amorphous granules attached to the first type of granule, and (3) extremely less electron-dense granules with a finely granular appearance. The diameter of this finely granular material was around 21 nm and a fibrous structure was also observed in or attached to this granule.

Adult↗