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Biomedical subjects

R Okada

Publications and source records attributed to R Okada.

At least 235 records · Page 13Linked to original sources
PubMed1981

Histopathological studies on the myocardial fibrosis and vascular lesion of rheumatic valvular disease.

To clarify the types and frequency of myocardial fibrosis and vascular lesions caused by different types of the rheumatic valvular disease, 41 autopsied hearts with rheumatic valvular lesions were examined and the following results were obtained. As to myocardial fibrosis, 1) perivascular fibrosis, caused mainly by perivascular inflammation and partly by myocardial strain, varied in grade according to the types of the valvular disease, i.e., most severe in mitral regurgitation (MR) and combined valvular disease (CVD) and least in mitral stenosis (MS); 2) Aschoff's nodes: 3 typical and 8 atypical cases were found; 3) perimycial fibrosis due to myocardial strain: most severe in MR and CVD and least in MS; and 4) irregular patchy fibrosis, caused mainly by myocarditis and partly by ischemia, was noticed in all types of the valvular disease. As to vascular lesion, 1) angitis was found in 7 cases and most frequently in MR; and 2) thickening of the intima and media was found in all types of valvular disease. Thus, myocardial fibrosis and vascular lesion varied according to the types of valvular disease, and not only hemodynamic changes but also myocardial fibrosis and vascular lesions might determine the prognosis of the valvular disease.

Adolescent↗
PubMed1981

A histopathological study on the hypertrophy of the atrioventricular conduction system.

A microscopical study of the AV conduction system using a serial sectioning method, was performed on 81 autopsied hearts with blocks anywhere in the hearts without arrhythmia. Pre-blockade hypertrophy in the AV conduction system was seen in 38%, 38%, 50-58% corresponded respectively to 3 degrees AV block, 1-2 degrees AV block and bundle branch block (including left hemiblock). Post-blockade hypertrophy was also observed in 58%, 38% and 42-25% of the above mentioned types of blocks respectively. Hypertrophy anywhere in the AV conduction system was seen in 77%, 42%, 78%, 39%, 30% and 74% of the cases with blocks, sick sinus syndrome, pre-excitation syndrome, other arrhythmias, normal hearts and hypertrophied hearts without arrhythmia, respectively. Hypertrophy of the proximal AV conduction system to the bundle of His was specific for arrhythmia group, whereas hypertrophy of the bundle branches occurred in either hypertrophy without arrhythmia or in bundle branch block. Hypertrophy of the Purkinje cells was remarkable in sudden cardiac death by clinically-proved ventricular fibrillation. Incidence of sclerosis of the AV node artery was high in the arrhythmia group, especially the highest (90%) in the sudden death group.

Heart Arrest↗
PubMed1981

[Cineangiographical and histopathological studies on hypertrophic myocardial disease with giant negative T wave (author's transl)].

A total of 19 patients consisted of 10 cases with hypertrophic cardiomyopathy (HCM), 6 with hypertensive heart disease (HHD) and 3 with professional bicycle racers with myocardial hypertrophy, showing giant negative T waves greater than 10 mm in precordial leads (GNT-group) was examined by catheterization, cineangiography and endomyocardial biopsy. Fourteen patients of myocardial hypertrophy consisted of 5 cases with HCM, 4 with HHD and 4 with professional bicycle racers without giant negative T (non-GNT-group) were selected as the control. The average of mid-ventricular wall thickness (Tm = 17.4 +/- 4.6 mm) and that of apical wall thickness (Ta = 18.5 +/- 3.6 mm) obtained from the left ventriculogram in GNT group were significantly greater than those in non-GNT group. The average of the apical hypertrophic index (Ta/Tm = 1.1 +/- 0.3) was also greater than that in non-GNT group. For the evaluation of hypertrophy of the papillary muscles, pattern of the hypertrophy was divided into 2 types by the feature of the left ventriculogram in systolic phase of right anterior oblique view, i.e., normal to moderate (type I) and severe (type II). In GNT group, 79% of patients belonged to the type II, whereas 71% of patients in non-GNT group belonged to type I. Histopathologically, the hypertrophy of heart muscle cells in GNT group was higher grade than in non-GNT group. Disarray of the muscle cells and myocardial fibrosis was not so prominent in GNT group. It was concluded that the mode of hypertrophy in GNT group was characterized by the existence of papillary muscle hypertrophy and had similarity to the hypertrophy of known etiologies such as mechanically overloaded myocardium which suggested to the secondary heart muscle diseases.

Adult↗
PubMed1981

Myocardial imaging with 9-[Te-123m]telluraheptadecanoic acid.

The distribution of radioactivity in the myocardium of rats and dogs infarcted by ligation of the left anterior coronary artery has been determined after intravenous injection of 9-[Te-123m]telluraheptadecanoic acid (Te-123m HDA]. In rats the normal myocardium concentrated radioactivity (3.7% +/- 0.28 injected dose/g) to nearly three times that in the zones of infarction (1.12% +/- 0.18 dose/g0. The focal defects detected in the gamma-camera images of rats and dogs correspond well with areas of infarction identified in the excised hearts by staining with triphenyltetrazolium chloride. The distribution of radioactivity from Te- 123m HDA in dog hearts sectioned at autopsy showed a linear correlation (r = 0.94) with blood flow as determined with scandium-46-labeled microspheres.

Animals↗