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Biomedical subjects

K Hirosawa

Publications and source records attributed to K Hirosawa.

At least 253 records · Page 14Linked to original sources
PubMed1976

Prinzmetal's variant angina. Coronary arteriogram and left ventriculogram during angina attack induced by methacholine.

Recently, in Prinzmetal's variant angina, many cases with normal coronary arteries have been reported. The anginal attacks frequently relapse after aortocoronary bypass grafting. It is frequently possible to induce an anginal attack by parasympathomimetic agents such as methacholine and pilocarpine. In this study, methacholine (0.13 mg per kilogram) was injected subcutaneously in three cases of this disease to induce an angina attack, and coronary arteriograms and left ventriculograms were recorded. In all cases a coronary arterial spasm corresponding to the site of the ST-segment elevation in the electrocardiogram was observed. Complete occlusion due to the spasm was observed even in the normal coronary artery. Asynergy was seen in the left ventricular wall corresponding to the site of the ST-segment elevation in the electrocardiogram.

Angina Pectoris↗
PubMed1976

Echocardiographic analysis of intracardiac anatomy in endocardial cushion defect.

A standard echocardiographic technique was proposed for an analysis of the intracardiac anatomy of endocardial cushion defect (ECD). It consisted of two beam directions, mitral and tricuspid, and two M-mode scans, between the mitral and tricuspid valves and between the mitral and aortic valves. Using this technique, echocardiographic studies were performed on 13 patients with ECD, including 10 patients with the incomplete form and three patients with the free-floating form. In patients with the incomplete form, an M-mode scan between the mitral and tricuspid valves showed the specific features of the interaction between the mitral valve, the interventricular septum, and the tricuspid valve, termed the "mitral-interventricular septal-tricuspid (MVT) connection." The systolic multiple echoes and the diastolic echoes of the so-called posterior leaflet of the mitral valve were constant findings in the mitral direction. The tricuspid valve, although less continuous, was recorded simultaneously with the mitral valve in the same direction. Ateriorly displacement of the anterior mitral leaflet was shown on an M-mode scan between the mitral and aortic valves, giving an echocardiographic representation of the angiocardiographic "goose-neck" sign. Evidence showing the presence of right ventricular volume overload was also found. In patients with the free-floating form, an anterior common A-V valve with a large excursion was recorded on an M-mode scan between the mitral and tricuspid valves. The valve was located posterior to the interventricular septum in the mitral direction and anterior to the septum in the tricuspid direction. There was no finding to show the interaction between the valve and the septum. The posterior common A-V valve was registered only in the mitral direction. Our technique made it possible to diagnose ECD, using a noninvasive echocardiographic method, and discriminate the free-floating form from other forms of ECD.

Adolescent↗
PubMed1975

Cytoplasmic membrane vesicles of Escherichia coli. A simple method for preparing the cytoplasmic and outer membranes.

A simple preparative method is described for isolation of the cytoplasmic and outer membranes from E. coli. The characteristics of both membrane fractions were studied chemically, biologically, and morphologically. Spheroplasts of E. coli K-12 strain W3092, prepared by treating cells with EDTA-lysozyme [EC 3.2.1.17], were disrupted in a French press. The crude membrane fraction was washed with 3 mM EDTA-10% (w/v) sucrose, pH 7.2, and the cytoplasmic membranes and outer membranes were separated by sucrose isopycnic density gradient centrifugation. The crude membrane fraction contained approximately 10% of the protein of the whole cells, 0.3% of the DNA, 0.7% of the RNA, 0.3% of the peptidoglycan, and about 30% of the lipopolysaccharide. The cytoplasmic membrane fraction was rich in phospholipid, while the outer membrane fraction contained much lipopolysaccharide and carbohydrate; the relative contents of lipopolysaccharide and carbohydrate per mg protein in the cytoplasmic membrane fraction were 12 and 40%, respectively, of the contents in the outer membrane fraction. Cytochrome b1, NADH oxidase, D-lactate dehydrogenase [EC 1.1.1.28], succinate dehydrogenase [EC 1.3.99.1], ATPase [EC 3.5.1.3], and activity for concentrative uptake of proline were found to be localized mainly in the cytoplasmic membranes; their specific activities in the outer membrane fraction were 1.5 to 3% of those in the cytoplasmic membrane fraction. In contrast, a phospholipase A appeared to be localized mainly in the outer membranes and its specific activity in the cytoplasmic membrane fraction was only 5% of that in the outer membrane fraction. The cytoplasmic and outer membrane fractions both appeared homogeneous in size and shape and show vesicular structures by electron microscopy. The advantages of this method for large scale preparation of the cytoplasmic and outer membrane fractions are discussed.

Adenosine Triphosphatases↗
PubMed1975

Prinzmetal's variant form of angina pectoris. Re-evaluation of mechanisms.

Thirty-five patients with typical Prinzmetal's variant angina were studied by coronary cineangiography. There was no demonstrable stenosis of the major coronary arteries in 19 patients. Nine patients with single coronary stenosis underwent aortocoronary bypass and had recurrence of the symptoms postoperatively. Administration of nifedipine effected complete cessation of the symptoms among patients formerly treated medically. Although surgical treatment did not effect permanent relief of pain, all patients initially treated surgically experienced relief of pain when nifedipine was administered. The pathophysiology of variant angina remains obscure. Our results suggest that neurohumoral factors exert more of an effect on the myocardial cell than on the coronary vessels.

Angina Pectoris↗