Biomedical subjects
Publications and source records attributed to F Yasuma.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
For the analysis of regional myocardial function, the measurement of regional myocardial surface area (RMA) was performed on the epicardial surface of myocardial segment lengths in a direction parallel to the superficial myocardial fibers (SLa) and at right angles to the first (SLb). In eight anesthetized dogs with opened-chests, measurements were done during a 60 s left anterior descending coronary artery occlusion and reperfusion. In the ischemic region, coronary occlusion resulted in dyskinesis in RMA, and the reduction of it during the ejection phase (ERA) decreased significantly at 10 s (p less than 0.05) and thereafter (p less than 0.01). Regional myocardial work (EWA) from the pressure-area loops during the ejection phase also decreased significantly at 10 s (p less than 0.05) and thereafter (p less than 0.01). The end-diastolic RMA (EDRMA) increased significantly at 30 s (p less than 0.01) and thereafter (p less than 0.01). In the non-ischemic region, compensatory changes were shown, namely ERA, EWA and EDRMA, increased significantly during occlusion. After reperfusion, recovery to the control level was prompt, and only EDRMA remained the increased value after 30 s (p less than 0.01). Between SLa and SLb, characteristics differed from each other, which suggested that the directional differences of SLs should be considered when regional myocardial function is assessed from unidirectional SL. The changes in RMA reflect both changes of SLa and SLb during coronary occlusion and reperfusion, and were more marked than each SL. Thus, the usefulness of RMA to assess regional myocardial function was demonstrated during coronary occlusion and reperfusion.
A patient with polymyositis manifesting severe myocardial damage and conduction block is described. A 57-year-old man presented dysarthria, dysphagia, proximal-dominant muscle weakness and wasting of the extremities. Muscle biopsy revealed degeneration and regeneration of muscle fibers and infiltration of mononuclear cells. After admission, muscle weakness rapidly progressed and mechanical ventilation was needed for respiratory failure. Simultaneously, cardiac symptom developed and resulted in bradycardia and trifascicular conduction block, which required a pacemaker. Echocardiogram revealed diffuse hypokinesia, ventricular enlargement and thickened wall. Marked elevations of serum CK-MB, cardiac myosin light chain I and cardiac troponin T were observed. High dose administration of methylprednisolone resulted in improvement of muscular and cardiac symptoms, and prevented complete heart block. Immediate and high dose of steroid therapy was considered to be effective for severe myocarditis in polymyositis.