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H Ohsawa

Publications and source records attributed to H Ohsawa.

At least 73 records · Page 4Linked to original sources
PubMed1989

Dual mechanism involved in the hydrolysis of polyphosphoinositides in rat pancreatic islets.

We investigated insulin secretion and inositol phosphate formation in intact and permeabilized rat pancreatic islets, the objective being to elucidate mechanisms of activation of phospholipase-C in pancreatic islets. The intact islets prelabeled with myo-[3H]inositol were incubated in Krebs-Ringer bicarbonate buffer containing 10 mM LiCl and 1 mM myoinositol. Glucose, alpha-ketoisocaproate (KIC), and sulfated cholecystokinin (CCK8S) increased insulin secretion and formation of [3H]inositol phosphate, [3H]inositol bisphosphate, and [3H] inositol trisphosphate. Mannoheptulose, a glucokinase inhibitor, inhibited glucose-induced insulin secretion and [3H]inositol phosphate formation; however, it did not inhibit KIC- and CCK8S-induced secretion and formation. Both glucose- and KIC-induced insulin secretion and [3H]inositol phosphate formation were blocked by 2,4-dinitrophenol, an uncoupler of oxidative phosphorylation in the mitochondria. The islets prelabeled with myo-[3H]inositol were permeabilized by digitonin and then incubated in intracellular mimicking medium containing 1 microM Ca2+ and 2.5 mM ATP. Glucose had no effect on [3H]inositol phosphate formation in the permeabilized islets, and CCK8S increased the formation of [3H]inositol phosphates. Thus, phospholipase-C in pancreatic islets is activated not only via ligand-receptor interaction in the plasma membrane in the case of hormone stimulation, but also by metabolic product(s) in the case of fuel stimulation.

Animals↗
PubMed1989

[The evaluation of left ventricular eccentric hypertrophy by 201Tl-myocardial scintigraphy].

In order to elucidate the mechanism of left ventricular eccentric hypertrophy in conditions of volume overload, Tl-201 myocardial scintigraphy was performed patients with aortic valve regurgitation and mitral valve regurgitation. There was a good relationship between the severity of Tl-defects, as determined by Tl-201 myocardial scintigraphy, and the changes in the T wave on the ECG on the one hand and the NYHA functional classification of heart diseases. In 17 of 18 patients where LVDd increased with increasing severity of Tl-defects and the defects were moderate to severe, LVDd was 65 mm or larger. There was a significant negative correlation between the washout rate for the whole circumference of the left ventricle, as determined by exercise Tl-201 SPECT, and LVDd (r = -0.603, p less than 0.01). The phenomenon of redistribution as determined by exercise Tl-201 myocardial scintigraphy was observed relatively early. Our results suggest that mechanical volume overload and ischemic changes are involved in left ventricular wall damage in left ventricular eccentric hypertrophy. For patients with moderate to severe Tl-defects valve replacement is indicated, no matter whether they may have heart failure or arrhythmia.

Adult↗
PubMed1989

[The evaluation of the therapeutic effect on acute myocardial infarction by radioisotope method--assessment of the intravenous injection of urokinase and comparison with the results of PTCR + PTCA].

The therapeutic effect of intravenous injection of Urokinase (UK method) on acute myocardial infarction (AMI) was studied and compared with the results of the therapeutic effect of PTCR + PTCA. The subjects comprise 108 cases with AMI, and a radioisotope examination was performed in the acute stage to calculate LVEF and Tl-defect ratio (Tl-DR). Measured by the UK method, Tl-DR in the group given 1.2 X 10(6) units of UK was 1.63 +/- 0.8, which was lower than the 2.4 +/- 1.33 for the group given 9.6 X 10(5) unit of UK, whereas a favorable therapeutic effect was obtained in both groups compared to 3.5 +/- 2.5 in the control group. In the group given UK within 6 hours after the onset of AMI, favorable results were obtained for LVEF (44.5 +/- 11.2%) and Tl-DR (1.68 +/- 0.82). The UK group showed as better results as the PTCR + PTCA group for LVEF (42.3 +/- 11.3 vs. 38.1 +/- 7.4) and Tl-DR (2.10 +/- 1.19 vs. 2.09 +/- 0.62). In both the UK and PTCR + PTCA groups, Tl-DR was well maintained despite an increase in the peak CPK and a decrease in LVEF, and, therefore, the conservation of stunned myocardium in the acute stage was suggested. From the above, it was concluded that the UK method is useful for treating AMI.

Aged↗
PubMed1988

Malignant schwannoma of the heart.

Primary cardiac tumor is an extremely rare disease entity. Only three cases of primary malignant cardiac schwannoma, the subject of this report, have been recorded in Japan. Recently, we encountered a case of malignant schwannoma in which retention of pericardial effusion was the first clinical finding. This case was a 30-year-old female, who had dyspnea at work, general fatigue, and fever. Striking cardiac expansion was seen, with a cardiothoracic ratio (CTR) of 69% on chest x-ray. Two-dimensional echocardiograms showed a large volume of pericardial effusion between the side wall of the left ventricle and the epicardium, and the presence of a parenchymatous tumor. An increase in tumor size was detected on chest computer tomography (CT) scan. Using a pump oxygenator, median sternotomy was performed to reach the epicardium. A pale yellow, soft tumor was seen in the left atrium near the left ventricle. Histologically, the patient was diagnosed as having a malignant schwannoma. We have reported a case of primary malignant schwannoma which was surmised to have arisen from the boundary between the atrium and the ventricle.

Adult↗
PubMed1988

IgA nephropathy and Henoch-Schönlein purpura nephritis with anterior uveitis.

Two patients with IgA nephropathy and a patient with Henoch-Schönlein purpura nephritis each associated with anterior uveitis are described. As anterior uveitis accompanying IgA nephropathy improved, renal manifestations were relieved. The patient with Henoch-Schönlein purpura nephritis suffered from not only anterior uveitis but also keratitis. It is suggested that immune mechanisms which induce IgA nephropathy may play a role in the development of anterior uveitis and keratitis.

Adolescent↗
PubMed1986

Evidence for direct effect of tolbutamide on hepatic glycogenolysis induced by Ca2+-dependent hormones.

The effects of tolbutamide and glibenclamide on hepatic glycogenolysis in perfused rat liver were investigated. Tolbutamide per se did not influence glucose output from the liver, but at therapeutic concentrations (about 350 microM) it significantly inhibited the glycogenolysis induced by phenylephrine, vasopressin and angiotensin II, while glibenclamide did not. Neither tolbutamide nor glibenclamide inhibited the glycogenolysis induced by glucagon. Tolbutamide potentiated the inhibitory effect of submaximal concentrations of insulin on glycogenolysis induced by phenylephrine. This effect of tolbutamide was elicitable even in the absence of calcium in the perfusate, and was additive to that of trifluoperazine. However, tolbutamide did not potentiate the inhibitory effect of insulin on glucagon-induced glycogenolysis. Tolbutamide inhibited the glycogenolysis induced by A23187, a calcium ionophore. These results indicate that, in addition to its known effect on insulin secretion, tolbutamide has a direct effect on the liver to inhibit glycogenolysis induced by Ca2+-dependent hormones (catecholamines, vasopressin and angiotensin II) and A23187. Thus, it is likely that tolbutamide inhibits the effect of Ca2+ mobilized by Ca2+-dependent hormones to stimulate glycogenolysis.

Angiotensin II↗
PubMed1986

[Colposcopy in dysplasia, carcinoma in situ and microinvasive cancer of the cervix--systematic diagnosis].

Recently colposcopy has come to be increasing used in the diagnosis of the early cervical cancer. We studied colposcopic findings (epithelial, vascular and glandular findings) of dysplasia, carcinoma in situ and microinvasive cancer of the uterine cervix. The results were as follows. We could classify the cases without white epithelium into microinvasive cancer and carcinoma in situ according to elevation or hollowness and roughness and the cases with I grade white epithelium (thin white epithelium) into severe dysplasia and mild or moderate dysplasia according to the existence of elevation, roughness, II type vessels and elevation of gland opening. Among the cases with II grade white epithelium (thick white epithelium) those without roughness, II type vessels and increased gland opening were mild or moderate dysplasia and most case with III or IV type vessels were microinvasive cancer. We concluded that more than half of the cases without III or IV type vessels spread to transverse pollution of white epithelium and lack or indefiniteness of gland opening, severe dysplasia with 0 finding, carcinoma in situ with 1 or 2 finding and microinvasive cancer with 3 findings. With these criteria, we were able to obtain high (93.4% with mean) correct diagnostic ratios.

Carcinoma in Situ↗