Biomedical subjects

Takayuki Noguchi

Publications and source records attributed to Takayuki Noguchi.

22 records · Page 2Linked to original sources

PubMed2002

Antithrombin reduces ischemia/reperfusion-induced renal injury in rats by inhibiting leukocyte activation through promotion of prostacyclin production.

Antithrombin (AT) supplementation in patients with severe sepsis has been shown to improve organ failures in which activated leukocytes are critically involved. However, the precise mechanism(s) for the therapeutic effects of AT is not well understood. We examined in rats whether AT reduces ischemia/reperfusion (I/R)-induced renal injury by inhibiting leukocyte activation. AT markedly reduced the I/R-induced renal dysfunction and histologic changes, whereas neither dansyl glutamylglycylarginyl chloromethyl ketone-treated factor Xa (DEGR-F.Xa), a selective inhibitor of thrombin generation, nor Trp49-modified AT, which lacks affinity for heparin, had any effect. Renal tissue levels of 6-keto-PGF(1 alpha), a stable metabolite of prostacyclin (PGI(2)), increased after renal I/R. AT enhanced the I/R-induced increases in renal tissue levels of 6-keto-PGF(1 alpha), whereas neither DEGR-F.Xa nor Trp49-modified AT had any effect. AT significantly inhibited I/R-induced decrease in renal tissue blood flow and the increase in the vascular permeability. Ischemia/reperfusion-induced increases in renal tissue levels of tumor necrosis factor-alpha, cytokine-induced neutrophil chemoattractant, and myeloperoxidase were significantly inhibited in animals given AT. Pretreatment of animals with indomethacin reversed the effects induced by AT. Iloprost, an analog of PGI(2), produced effects similar to those induced by AT. These observations strongly suggest that AT reduces the I/R-induced renal injury by inhibiting leukocyte activation. The therapeutic effects of AT might be mainly mediated by PGI(2) released from endothelial cells through interaction of AT with cell surface glycosaminoglycans.

6-Ketoprostaglandin F1 alpha↗

PubMed2002

Change in free radical-related substances in plasma following ischemia-reperfusion in rat liver.

In order to clarify the relationship between free radicals and liver injury due to ischemia-reperfusion, we investigated the dynamics of radical-related substances in the blood of rats after liver ischemia-reperfusion. Subsequent to 60 min of liver ischemia, the generation of reactive oxygen species (ROS) from polymorphonuclear leukocytes (PMNs) initiated by phorbol myristate acetate (PMA) and lipid peroxidation significantly increased 2 h after reperfusion and showed peak values at 8-10 h. These values returned to the control level 32 h after reperfusion. The levels of nitric oxide metabolites (NO(x), NO(2)(-)+NO(3)(-)) increased biphasically at 10 and 32 h during the period of reperfusion, but did not return to control levels. Cu,Zn-superoxide dismutase (SOD) levels increased immediately after 5 min of reperfusion and showed a peak value after 20 min. This increase diminished gradually and returned to the control level 10 h after reperfusion. Mn-SOD increased 2 h after reperfusion, and this level was maintained for 48 h. The levels did not show increases at the end of ischemia and were nearly identical to the pre-ischemia levels. These finding obtained from the dynamics of radical-related substances are considered very meaningful for investigating mechanisms in the pathogenesis of liver injury by ischemia-reperfusion, and are clinically important in liver transplantation.

Journal Article↗

PubMed2002

Pharmacokinetics of propofol in elderly coronary artery bypass graft patients under total intravenous anesthesia.

The present paper investigates the pharmacokinetics of propofol in the plasma of two elderly patients operated on under total intravenous anesthesia using propofol. A 78-year-old (patient A) and a 76-year-old (patient B), both Japanese men with unstable angina pectoris, were operated on for coronary artery bypass grafts. For the induction of anesthesia, 1.5 mg/kg propofol was administered as a single bolus infusion, and anesthesia was maintained using the step-down infusion regimens of propofol. Propofol concentration in the plasma was measured by HPLC with a fluorescence detector. The simulation curves, following the two-compartment model, fitted well to the profiles of the individual data of propofol concentrations in the plasma. When 4 mg/kg/h of propofol was administered to both patients while maintaining anesthesia, propofol concentrations in the plasma were maintained at over 1.0 microg/ml. In patient A, the propofol concentration in the plasma was 140 ng/ml at 6 h after the end of the infusion. In patient B, the propofol concentrations in the plasma were 73 ng/ml at 6 h and 35 ng/ml at 12 h after the end of the infusion. The apparent distribution volumes of patients A and B were 1.43 and 1.62 l/kg, respectively. The half-lives of propofol in the plasma of patients A and B were estimated to be 13.3 and 17.4 min as the a phase, and 10.1 and 10.5 h as the beta phase, respectively. In elderly patients with cardiac surgery, the maintenance concentrations of propofol in the plasma were enough to maintain a concentration of 1.0 microg/ml, and the half-life may be longer than previously reported values in adult patients.

Aged↗

PubMed2002

[Effects of olprinone hydrochloride on intraocular pressure and ocular blood flow in patients after cardiac surgery under cardiopulmonary bypass].

BACKGROUND: We evaluated the effect of olprinone hydrochloride on intraocular pressure (IOP) and ocular blood flow in patients after cardiac surgery under cardiopulmonary bypass (CPB). METHODS: Nine patients after cardiac surgery under CPB were investigated. We measured IOP of the left eye using tonometer (Tonopen XL, BIO RAD, Osaka), and mean blood flow velocity in the left ophthalmic artery (Vm) and calculated the pulsatility index in the left ophthalmic artery (PI) using 2 MHz Doppler ultrasound system (Multidop P, DWL, Germany). After baseline measurement, the olprinone hydrochloride loading dosage was increased from 0.15 to 0.3 microgram.kg-1.min-1 every 60 minutes. The intraocular pressure and ocular blood flow were measured at each point. RESULTS: IOP and PI decreased significantly, and Vm increased significantly at the infusion rate of 0.3 microgram.kg-1.min-1 from baseline. There was a significant linear correlations between IOP and Vm. CONCLUSION: We demonstrated that olprinone hydrochloride led to a decrease in IOP and an increase in ocular blood flow in patients after cardiac surgery under CPB.

Aged↗