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Biomedical subjects

K Tahara

Publications and source records attributed to K Tahara.

At least 127 records · Page 7Linked to original sources
PubMed1986

Myocarditis with myocardial infarction like findings in a 3-year old girl.

A 3 year-old Japanese girl had an acute onset associated with vomiting. The electrocardiogram (ECG) indicated changes similar to those of acute myocardial infarction (MI); there was no past history of kawasaki disease. Selective coronary angiography taken on the 28th day of illness revealed no abnormality. Thallium 201 scintigraphy was also performed and it revealed that the area of absent myocardial uptake was in the anterior wall. In serological findings, antibody titers against Coxsackie B-3 virus had risen significantly; therefore acute myocarditis caused by Coxsackie B-3 virus infection was diagnosed.

Antibodies, Viral↗
PubMed1985

Involvement of 5-lipoxygenase metabolites in ACTH-stimulated corticosteroidogenesis in rat adrenal glands.

Various lipoxygenase (LO) products of arachidonic acid (AA) have been found to have potent biological activities and modulate physiological processes in various cells including endocrine cells. However, no studies concerning LO products in adrenocortical cells have been reported. The present study was performed to investigate LO products in rat adrenocortical cells and its role in ACTH-stimulated adrenal steroidogenesis. LO metabolites produced in ACTH-stimulated rat adrenocortical cells prelabeled with [3H]AA was analyzed by reverse phase and straight phase HPLC and two 5-LO products, 5-hydroxyeicosatetraenoic acid (5-HETE) and leukotriene B4 (LTB4) were identified. ACTH-induced 5-HETE and LTB4 production in adrenal cells was dose dependently inhibited by AA861, a specific inhibitor of 5-LO. AA861 reduced ACTH-stimulated corticosteroid production without any change in cyclic AMP formation, while indomethacin did not affect both corticosteroid and cyclic AMP production. Reduced steroidogenesis by AA861 was reversed by the addition of 5-hydroperoxyeicosatetraenoic acid (5-HPETE). Also exogenously added 5-HPETE dose dependently augmented ACTH-stimulated corticosteroid production without any concomitant change in cyclic AMP production. However, 5-HETE and LTB4 had no such effect. These results indicate that 5-LO pathway is present in rat adrenocortical cells and its metabolites, most likely 5-HPETE, may play an important role in adrenal steroidogenesis.

Adrenal Cortex↗
PubMed1983

Studies on the mechanism of antiaggregatory effect of Moutan Cortex.

The effects of Moutan Cortex and one of its major components, paeonol, on platelet aggregation and arachidonic acid (AA) metabolism in human platelets were studied. One week oral administration of water extract of Moutan Cortex [Moutan Cortex (w), 3 g/day] significantly reduced platelet aggregation and thromboxane B2 (TXB2) formation induced by collagen, epinephrine and ADP. Paeonol dose-dependently inhibited ADP and collagen induced platelet aggregation in vitro. Moutan Cortex (w) and paeonol dose-dependently inhibited the conversion of exogenous [14C]AA to [14C]heptadecatetraenoic acid [( 14C]HHT) and [14C]TXB2 by washed human platelets, while both of them increased its conversion to [14C]12-hydroxy eicosatetraenoic acid [( 14C]12-HETE). High dose of Moutan Cortex (w) inhibited the release of [14C]AA from prelabeled platelets in vitro, while paeonol did not. These results suggest that a reduction in platelet aggregation by the oral administration of Moutan Cortex might be ascribed to a decrease in thromboxane synthesis and that paeonol might play an important role in the antiaggregatory effect of Moutan Cortex because of its potent inhibitory effect on platelet aggregation and thromboxane formation.

Acetophenones↗
PubMed1982

[Clinical use of acetylspiramycin for primary atypical pneumonia in the field of pediatrics].

Thirty-one patients with primary atypical pneumonia (16 patients diagnosed as Mycoplasma pneumonia) who visited our Department of Pediatrics between March and December, 1981 were treated with 200 mg tablets of acetylspiramycin. Clinical effects were studied, and the results were as follows. 1. Acetylspriramycin, in principle 30 mg/kg/day, was given to 31 patients with primary atypical pneumonia. The effective rate was 87.1%. (As for the patients with Mycoplasma pneumonia, the effective rate was 93.8%). 2. There was 1 ineffective case and it was judged as a case of other viral pneumonia by the results of clinical laboratory tests. 3. The only side effect observed was eruption which occurred on the 6th day of administration in 1 case and disappeared after the change of administration. From the above results, acetylspiramycin is thought to be an effective antibiotic on primary atypical pneumonia.

Adolescent↗
PubMed1980

Permeability properties of a multilayer planar membrane.

The permeability properties of multilayer planar membranes of uniformly oriented lipids between a pair of cellulose sheets were investigated. The effect of the two cellulose sheets supporting the lipid membrane on the glucose or the Ca permeation was subtracted empirically, and values of 5 X 10(-6) and 8 X 10(-6) cm/s were thus obtained for the permeability coefficients of an egg yolk lecithin (egg PC)-cholesterol membrane of about 200 bilayers to Ca2+ and glucose, respectively. These values are discussed as compared with the permeability coefficients of other model membranes. The membrane permeability was moderately affected by the addition of chemical substances to egg PC membranes. It was reduced by the presence of cholesterol, but enhanced by the presence of isopropanol, n-butanol, or thymol in the same solution above a critical concentration of each compound. These and previous observations (8) suggest that a close correlation may exist between the permeability of the membrane and the orientation of the membrane lipids. The glucose permeation was drastically suppressed by the presence of Ca2+ (10 mM) in the sample solution with the membrane containing phosphatidylserine, but was not at all suppressed with the membrane of the egg PC-cholesterol mixture.

1-Propanol↗
PubMedDate not supplied

Acute rejection in allogeneic rodent small bowel transplantation causes smooth muscle dysfunction via an inflammatory response within the intestinal muscularis.

INTRODUCTION: Isogeneic intestinal transplantation elicits an inflammatory response within the intestinal muscularis that is associated with dysmotility. Usually the inflammation and the postoperative motor dysfunction resolve within a few days after small bowel transplantation (SBTx). However, the onset of acute rejection in allogeneic SBTx is again associated with dysmotility. We hypothesized that dysmotility during acute rejection is based on coexpression of kinetically active mediators by the alloreactive leucocyte infiltrate. MATERIALS AND METHODS: Rat SBTx (BN to Lew and BN to BN) was performed without immunosuppression. Animals were sacrificed at 1, 4, and 7 days after SBTx. Leukocyte infiltration was investigated in muscularis whole mounts by immunohistochemistry. Mediator mRNA expression was determined by reverse transcriptase polymerase chain reaction. Muscle contractility was assessed in a standard organ bath. RESULTS: Transplanted animals showed a significant inflammatory response within the muscularis at day 1 after SBTx. However, allogeneic transplanted animals exhibited a significant second inflammatory peak at day 7 (mRNA induction: iNOS 150-fold; tumor necrosis factor-alpha 18-fold; interferon-gamma 397-fold), parallel to the onset of rejection. This change was associated with a significant leukocyte infiltration. Compared to controls, allogeneic transplanted animals showed a 29% decrease in smooth muscle contractility on days 1 and 4 and a 71% decrease of contractility on postoperative day 7. CONCLUSIONS: The motor dysfunction of transplanted small bowel during acute rejection is associated with an inflammatory reaction in the intestinal muscularis. The initial unspecific inflammation process immediately after transplantation is reactivated and intensified during acute rejection.

Animals↗
PubMedDate not supplied

Mechanism and impact of organ harvesting and ischemia-reperfusion injury within the graft muscularis in rat small bowel transplantation.

INTRODUCTION: Inflammatory events within the gut muscularis contribute to dysmotility. We hypothesized that manipulation during organ harvesting initiated an inflammatory response via muscularis macrophages and that this cascade was amplified during reperfusion. METHODS: Small bowel transplantation was performed in Lewis rats. To investigate the impact of organ harvesting on muscularis inflammation, cold whole-body perfusion was performed after versus prior to organ harvesting. The role of macrophages was investigated by transplantation of the macrophage-depleted gut. Leukocyte infiltration was investigated in muscularis whole mounts. Mediator mRNA expression was determined by real-time reverse transcriptase polymerase chain reaction. Contractility was assessed in a standard organ bath. RESULTS: Organ harvesting and ischemia-reperfusion induced leukocyte recruitment and mRNA upregulation in the muscularis: interleukin-6 12217-fold, monocyte chemoattractant protein-1 62-fold, ICAM-1 12-fold, cyclooxygenase-2: 8-fold, iNOS: 150-fold. Although organ harvesting with cold ischemia prevented early gene expression, peak expression at 3-hour reperfusion was not changed by modification of the harvesting technique. Compared to controls, transplanted animals showed a 63% decrease in smooth muscle contractility. In contrast, transplanted macrophage-depleted gut exhibited significantly fewer leukocytes and only a 16% decrease in contractility. CONCLUSIONS: Gut manipulation during organ harvesting initiates an inflammatory response within the muscularis that is massively intensified during reperfusion. This change contributes to muscular dysfunction. Furthermore, the results suggested that resident macrophages play a key role in initiating this process.

Animals↗
PubMedDate not supplied

Experimental evaluation of a newly developed ultrathin silicone layer coated hollow fiber oxygenator.

The authors developed a new membrane oxygenator that consists of microporous polypropylene hollow fibers coated with a 0.2 micron ultrathin silicone layer. Five venoarterial bypasses were conducted on mongrel dogs for 24 hr using these new oxygenators. The blood flow rate was maintained at 750 ml/min, and the V/Q ratio was maintained at 1:1. As a control, three venoarterial bypasses were conducted under the same conditions using an oxygenator with the same design but without the silicone coating. Eight to 16 hr after the initiation of bypass, severe plasma leakage occurred in all control experiments, so the bypasses were terminated. However, plasma leakage did not occur throughout the 24 hr of any of the experiments using the new oxygenator. The O2 transfer rate of the new oxygenators after 24 hr of perfusion was 59.7 +/- 6.6 ml/min/m2, and the plasma free hemoglobin level 8 hr after the initiation of bypass was 41.4 +/- 40.2 mg/dl, compared with 145.3 +/- 189.6 mg/dl in the control group. Scanning electron microscopic examination of the silicone coated fibers after 24 hr of bypass revealed a few scattered platelet adherents and no damage to the silicone coated surface. These results suggest that this new oxygenator has satisfactory gas transfer and good durability.

Animals↗
PubMedDate not supplied

Continuous isoproterenol inhalation therapy in children with severe asthmatic attack.

We studied the 1-type isoproterenol inhalation therapy for patients with severe asthmatic attacks who were admitted at the Department of Allergy of National Children's Hospital from 1981 to 1991. One hour after l-type isoproterenol inhalation therapy, statistically significant effects were noted with regard to the asthmatic status. Moreover, no side effect was found amoung the subjects. From these data, 1-type isoproterenol inhalation therapy is thought to be effective for severe asthmatic attacks.

Administration, Inhalation↗