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Biomedical subjects

Yusuke Kawai

Publications and source records attributed to Yusuke Kawai.

5 recordsLinked to original sources
PubMed2006

Diabetes mellitus reduces the antiarrhythmic effect of ion channel blockers.

We designed the present study to examine whether diabetes mellitus affects the antiarrhythmic effect of flecainide, a sodium channel blocker, E-4031, a potassium channel blocker, and verapamil, a calcium channel blocker, in diabetic rats. The experiments were performed in intact and diabetic rats 2, 4, and 6 wk after administration of streptozotocin. Rats were anesthetized with halothane and monitored continuously for arterial blood pressure and premature ventricular contractions. The arrhythmogenic dose of epinephrine was defined as the smallest dose producing 3 or more premature ventricular contractions within a 15-s period. The arrhythmogenic doses of epinephrine in the presence of flecainide were 8.2 +/- 2.2 (mean +/- sd), 7.4 +/- 6.1, 5.5 +/- 2.8, and 2.0 +/- 0.5 microg/kg in intact and diabetic rats 2, 4, and 6 wk after streptozotocin administration, respectively. Similarly, the arrhythmogenic doses of epinephrine in the presence of E-4031 were 7.7 +/- 2.6, 2.3 +/- 0.7, 2.0 +/- 0.7, and 1.2 +/- 0.5 microg/kg, and those in the presence of verapamil were 8.2 +/- 2.1, 3.1 +/- 1.2, 2.3 +/- 0.9, and 1.5 +/- 0.5 microg/kg. Insulin partially recovered the antiarrhythmic effect of the blockers. We concluded that diabetes mellitus reduces the antiarrhythmic effects of flecainide, E-4031, and verapamil.

Animals↗
PubMed2005

Diffusive motion of molecules in submonolayer liquid films on a solid surface.

The spreading of submonolayer liquid polymer films on a solid surface that consist of molecules with different mobilities was investigated. The molecular conformations of the adsorbed and free molecules were estimated from the dispersive surface energy measurement and the relationship between the diffusion coefficient of the free molecules and the coverage of the adsorbed molecules were obtained from the spreading profile measurement. A free mobile molecule lies flat on the solid surface and an adsorbed molecule lies less flat than a mobile one. The relation between the diffusion coefficient and the coverage can be explained by the percolation model at a small coverage and it can be explained by the reptation model at a large coverage.

Journal Article↗
PubMed2004

Prophylactic effect of intravenous nicorandil on perioperative myocardial damage in patients undergoing off-pump coronary artery bypass surgery.

Nicorandil, ATP sensitive potassium channel opener, is shown to reduce coronary events for patients with stable angina. The present study was designed to examine the protective potential of nicorandil for patients undergoing off-pump coronary artery bypass grafting. Twenty-four patients undergoing off-pump coronary artery bypass grafting were randomly assigned to two groups, one receiving continuous infusion of nicorandil (1.0 microg.kg(-1).min(-1)) (n = 12) through anesthesia to next day and the other receiving no nicorandil for control (n = 12). For assessing myocardial injury, heart type fatty acid binding protein, troponin T, and creatine kinase MB isoform were determined during the first 15 hours after reperfusion. The concentration of heart type fatty acid binding protein in the nicorandil group was significantly lower than that in the control group. On the other hand, the concentrations of troponin T and creatine kinase MB isoform in the nicorandil group were lower than those in the control group, but the differences did not reach statistical significance. Furthermore, nicorandil did not affect the patients' hemodynamic variables. Our data suggest that the infusion of nicorandil provides small myocardial protection without affecting hemodynamic parameters during perioperative treatment of patients undergoing off-pump coronary artery bypass grafting.

Aged↗
PubMed2002

Nicorandil prevents epinephrine-induced arrhythmias in halothane-anesthetized rats by nitric oxide-dependent mechanism.

The effect of opening ATP-sensitive K(+) channels on the genesis of arrhythmias is still controversial. We investigated the effect of nicorandil, an ATP-sensitive K(+) channel opener, on the genesis of halothane-epinephrine arrhythmias in rats. We also clarified the involvement of nitric oxide in the effect of nicorandil. Furthermore, we studied the effect of levcromakalim, another ATP-sensitive K(+) channel opener, for comparison. Nicorandil and levcromakalim significantly increased the arrhythmogenic thresholds of epinephrine in a dose-dependent manner. On the other hand, nitroprusside, a potent vasodilator (5.0 micro g/kg per min), did not exert antiarrhythmic action significantly. Both glibenclamide (non-specific ATP-sensitive K(+) channel blocker) and 5-hydroxydecanoate (mitochondrial ATP-sensitive K(+) channel blocker) inhibited the antiarrhythmic action of nicorandil. Although pretreatment with N-omega-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, did not modulate the genesis of halothane-epinephrine arrhythmias in the absence of nicorandil, it completely abolished the antiarrhythmic action of nicorandil, but not the effect of levcromakalim. We concluded that nicorandil dose-dependently inhibited halothane-epinephrine arrhythmias through mitochondrial ATP-sensitive K(+) channels and nitric oxide is required for the antiarrhythmic effect of nicorandil.

Anesthetics, Inhalation↗