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Biomedical subjects

Y Inada

Publications and source records attributed to Y Inada.

At least 271 records · Page 15Linked to original sources
PubMed1985

Ester-exchange catalyzed by lipase modified with polyethylene glycol.

Lipoprotein lipase was modified with 2,4-bis(O-methoxypolyethylene glycol)-6-chloro-s-triazine; forty-six percent out of seven amino groups in the molecule were substituted. The modified lipase catalyzed ester-exchange reactions between an ester and an alcohol, between an ester and an acid, and between two esters. The modified enzyme catalyzed these reactions not only in organic solvents, but also in straight hydrophobic substrates. As the modified enzyme was extremely stable at elevated temperature, for example at 70 degrees C, this can find many practical applications.

Caproates↗
PubMed1985

Novel plasmin inhibitors released from bovine platelets during aggregation.

The antifibrinolytic activity was found in the medium of platelet suspension in the process of platelet aggregation induced by thrombin, ADP and 5-hydroxytryptamine. The antifibrinolytic activity was closely associated with inhibitors in platelets, which specifically inhibited plasmin activity and not inhibited other proteases such as urokinase, thrombin and trypsin. One casein unit of plasmin activity was inhibited by the inhibitors released from approximately 10(8) platelets during the aggregation with thrombin. By the activity staining analysis, it was found that there are two kinds of plasmin inhibitors with molecular weights of 25,000 and 17,000. The physiological function of these inhibitors was discussed in relation to the formation of thrombus.

Adenosine Diphosphate↗
PubMed1985

Synergism of vitamins A and C on fibrinolysis.

A hitherto unknown synergism exerted by retinol (vitamin A) and L-ascorbic acid (vitamin C) was discovered using endothelial cells. Retinol stimulated the extracellular and intracellular activities of plasminogen activator up to approximately 8- and 4-fold from the control values, respectively. L-Ascorbic acid enhanced the extracellular and intracellular activities up to approximately 1.5-fold. Above all it was demonstrated that their effects on extracellular activity were synergistic; simultaneous administration of these two vitamins enhanced the extracellular activity up to a 20- to 50-fold. Synthesis of plasminogen activator induced with vitamins A and C was inhibited by a protein synthesis inhibitor, cycloheximide.

Animals↗
PubMed1985

Activation and stabilization of asparaginase by anti-asparaginase IgG and its Fab.

Modified asparaginase, in which 4 tryptophan residues were modified with 2-hydroxy-5-nitrobenzyl bromide, had little enzymic activity and retained immunoreactivity [(1976) FEBS Lett. 65, 11-15]. Addition of IgG or its Fab towards asparaginase to the modified asparaginase gave rise to marked enhancement of the enzymic activity. Native asparaginase (4 subunits) lost the enzymic activity due to dissociation into subunits by dilution of the enzyme solution. However, in the presence of Fab, asparaginase did not lose enzymic activity on dilution, probably due to no dissociation into subunits occurring.

Antigen-Antibody Complex↗
PubMed1985

Delay of the initiation of hypertension in spontaneously hypertensive rats by CV-4151, a specific thromboxane A2 synthetase inhibitor.

When CV-4151, a specific thromboxane (TX) A2 synthetase inhibitor, was given orally to 4 week old (4w) spontaneously hypertensive rats (SHR) daily for 3 weeks, the initiation of hypertension was delayed by about one week. The agent increased urinary excretion of water, sodium and creatinine, reduced that of TXA2 (as TXB2), increased that of PGI2 (as 6-keto-PGF1 alpha) and enhanced urinary PGI2/TXA2. In 4w Wistar-Kyoto rats (WKY) and 18w SHR was established hypertension, the agent had little effect on blood pressure and renal function. In isolated, perfused kidneys of 6w SHR, CV-4151 markedly inhibited both arachidonic acid-induced pressor action and production of TXA2. TXA2 synthetase activity in renal cortical microsomes of 5w SHR was approximately 1.5 times higher than that in age-matched WKY. CV-4151 inhibited TXA2 synthetase activity of medullary and cortical microsomes more effectively in 5w SHR than in age-matched WKY. Thus, in young SHR, the TXA2 synthetase inhibitor seemed to improve renal function by altering the balance of renal TXA2 and PGI2 biosynthesis and subsequently caused a delay in the initiation of hypertension. The present findings lend support to the idea that an imbalance in the renal TXA2-PGI2 biosynthesis may be involved in the initiation of hypertension in SHR.

Animals↗
PubMed1985

Lysis of platelets and erythrocytes by the incorporation of a unique oxygenated sterol: 22R-hydroxycholesterol.

We have found that an oxygenated sterol, 22R-hydroxycholesterol [(22R)-5-cholestene-3 beta, 22-diol], lyses not only platelets but also erythrocytes in a dose-dependent manner. The lysis of platelets and erythrocytes were evidenced by the release of intracellular proteins, lactate dehydrogenase and hemoglobin, respectively. Their morphological change was shown by scanning electron microscopy. Elevated temperature was required for the lysis, probably to redistribute the sterol in the lipid bilayers in the plasma membranes. When the sterol was incorporated at low temperature, the temperature had to be raised to readily lyse cells. This lytic effect was, surprisingly enough, restricted to the R-isomer; the S-isomer was only marginally effective. Furthermore, sitosterol and other oxygenated sterols, with a hydroxyl group at different positions in the side chain of cholesterol, were much less lytic, regardless of the configuration of the hydroxyl group introduced. A possible mechanism for this interesting phenomenon will be discussed in relation with a structural alteration in lipid bilayers in plasma membranes brought about by the incorporation of this unique oxygenated sterol.

Animals↗
PubMed1985

Effect of intraluminal bile on the feedback regulatory mechanism of pancreatic enzyme secretion in conscious rats.

The effect of intraluminal bile on the well-known feedback regulatory mechanism of exocrine pancreatic secretion exerted by intraluminal trypsin was investigated in conscious rats with pancreatic, biliary and duodenal fistulae. The stimulated pancreatic enzyme secretion caused by diversion of bile-pancreatic juice from the intestine was apparently suppressed by intraduodenal reintroduction of pancreatic juice or bile-pancreatic juice, while it was slightly suppressed by intraduodenal reintroduction of bile. Although additional reintroduction of bile did not alter the already suppressed pancreatic enzyme secretion by the presence of pancreatic juice in the intestine, diversion of bile stimulated the suppressed pancreatic enzyme secretion by intraluminal bile-pancreatic juice. Infusion of sodium taurocholate into the duodenum with diversion of bile-pancreatic juice effectively inhibited pancreatic enzyme secretion. The inhibitory effect seemed to be dependent on the concentration of taurocholate infused into the duodenum. The results suggest that bile and bile acid have an important role in the feedback regulatory mechanism of pancreatic enzyme secretion, at least partly directly inhibiting the secretion.

Amylases↗