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Biomedical subjects

A Ohsumi

Publications and source records attributed to A Ohsumi.

At least 19 recordsLinked to original sources

Alteration of gap junction proteins (connexins) following lateral fluid percussion injury in rats.

Gap junctions are intercellular channels that mediate the cytoplasmic exchange of small hydrophilic molecules and are formed by a family of integral membrane proteins called connexins (Cxs). Cx43 is expressed predominantly in astrocytes, while Cx36 is expressed in neurons. In this study, we show alteration of Cx43 and Cx36 in the hippocampus after traumatic brain injury in rats. Adult male Sprague-Dawley rats were subjected to lateral fluid percussion injury of moderate severity. Brain coronal sections were used for immunohistochemistry with Cx43 and Cx36 antibodies. Cx43 immunoreactivity was increased in reactive astrocytes in the damaged hippocampus 24 hours after injury, and persisted for 72 hours. On the other hand, Cx36 immunoreactivity increased in CA3 neurons 1 hour after injury, and decreased later. These results indicate that gap junctions might participate in the pathophysiological process after traumatic brain injury.

Adaptation, Physiological↗

[Late results of acute aortic dissection: analysis of the patients longer than five years after the operation].

Between 1985 and 1992, 28 patients of acute type A aortic dissection were operated on at our department. Our surgical strategy for this disease is "limited aortic resection", that is to avoid replacement of the entire arch except for the patients with arch tear that cannot be resected without total arch replacement. There were one operative mortality due to post transfusion GVHD, and ten late mortality (rupture of the residual dissecting aneurysm 3; complication of the late reoperation 3; cerebrovascular disease 2; pulmonary infection 2). Actuarial survival rate of all cases is 92.9%, 62.9%, and 58.4% at 1, 5, and 10 years, respectively. Comparing the patients whose primary tear was resected or not resected, there was no difference in the rate of residual dissection (12/16, 75% vs 5/6, 83.3%; primary tear resected vs not resected), the rate of late reoperation (3/16, 18.8% vs 1/6, 16.7%), nor actuarial survival rate (90.5% vs 100%, 66.7% vs %, 53.6% vs 71.4%, at 1, 5, 10 years, respectively). There were three cases with Marfan's syndrome, and all three cases died of the rupture of the residual dissection. We will follow the policy of the "limited aortic resection" unless the operative mortality of the entire arch replacement is proved as good as that of the ascending or hemiarch replacement. Because of the poor late results of the patients with Marfan's syndrome, entire arch replacement at the initial surgery and aggressive reoperation for the residual dissection is necessary.

Acute Disease↗

[Pneumonitis induced by the herbal medicine Sho-saiko-to in Japan].

We studied the clinical characteristics of pneumonitis induced by Sho-saiko-to (SST). Of 94 cases reported to a drug maker, 72 were judged to be SST-induced pneumonitis (52 men and 20 women, mean age 63.7 years). Most patients took SST for chronic liver diseases due to infection with the hepatitis C virus. The mean duration of SST therapy before the onset of pneumonitis was 50.2 +/- 42.1 days. Most patients presented with coughing, dyspnea, and fever of acute onset. Chest X-ray films showed diffuse ground-glass shadows and infiltration. Abnormally high levels of C-reactive protein and lactate dehydrogenase were common, as was hypoxia. Analysis of bronchoalveolar lavage fluid revealed abnormally high percentages of lymphocytes and neutrophils and a low CD4/CD8 ratio. Although 64 of 72 patients survived after cessation of SST only or steroid therapy, 8 died of respiratory failure despite high-dose steroid therapy. Compared with patients who survived those who died were more likely to have an underlying lung disease, had been taking SST longer after the onset of pneumonitis, and had more severe hypoxemia.

Adverse Drug Reaction Reporting Systems↗

Effects of hypocapnia and hypercapnia on splanchnic circulation and hepatic function in the beagle.

The effects of mild hypocapnia (PaCO2 22 mm Hg) and hypercapnia (PaCO2 59 mm Hg) on the splanchnic circulation and hepatic function were studied in six pentobarbital anesthetized, laparotomized, mechanically ventilated beagles. Tidal volume and respiratory frequency were held constant throughout the measurements. Hepatic artery blood flow (HABF) and portal vein blood flow (PVBF) were measured by electromagnetic flowmeters. Hepatic function was assessed by indocyanine green (ICG) elimination kinetic analysis after intravenous injection of the dye. Hypocapnia caused a decrease in HABF without affecting the systemic circulation. Hypercapnia, on the other hand, caused a significant increase in cardiac output without changing mean arterial pressure. There was a significant increase in PVBF and total hepatic blood flow (THBF = PVBF + HABF). Despite the increases in PVBF and THBF, the half-life of ICG was significantly longer during hypercapnia (9.09 +/- 0.79 min) than during hypocapnia (7.16 +/- 0.37 min), and plasma ICG clearance was smaller during hypercapnia (4.79 +/- 0.44 ml.min-1) than during hypocapnia (5.44 +/- 0.33 ml.min-1) or normocapnia (5.27 +/- 0.50 ml.min-1), indicating the depressed hepatic function during hypercapnia. We conclude that mild hypocapnia decreases HABF without affecting hepatic function and that mild hypercapnia is associated with a depression of hepatic function in spite of the increases in PVBF and THBF.

Animals↗

[Dose dependent effects of dichloroacetate on lactic acidosis in dogs].

Dose dependent effects of DCA (dichloroacetate) on lactic acidosis were studied in 30 mongrel dogs under pentobarbital anesthesia. Lactic acidosis was induced by infusion of either lactate (n = 15) or pyruvate (n = 15) for 20 min. In each dog, saline or DCA (100 mg.kg-1 or 300 mg.kg-1) was given for ten min iv. at ten min after the beginning of lactate or pyruvate infusions. Reduction in serum pyruvate levels was more prominent than that in lactate levels in both the lactate and pyruvate infusion groups. DCA in a dose of 100 mg.kg-1 was more effective to reduce serum pyruvate levels and arterial pH than 300 mg.kg-1 of DCA. There were no differences between saline and DCA (100 mg.kg-1 or 300 mg.kg-1) administrations in mean arterial pressure and cardiac index. This study confirmed the hypothesis that DCA reduces serum lactate levels via acceleration of pyruvate metabolism. It was concluded that the ability of DCA to reduce serum lactate levels is dose-dependent and a large dose of DCA (300 mg.kg-1) would not be necessary for lactic acidosis.

Acetates↗