Tatsuru Niimura

Effect of chronic administration of propranolol on lipoprotein composition

Chronic effects of propranolol on plasma lipids and lipoprotein composition were examined in ten patients who had previous strokes and normal plasma lipids. Although plasma triglyceride and total cholesterol were not affected by propranolol, a slight decrease of free cholesterol and phospholipids and a significant increase of free fatty acids were observed in the eighth week of propranolol treatment. Reciprocal changes were observed in lipoprotein composition; these were an increase in lipids of very low-density lipoprotein and a decrease in lipids of both low-density and high-density lipoproteins. Postheparin lipolytic activity was significantly suppressed by the administration of propranolol. Inhibition of lipoprotein lipase by propranolol was considered to have played a role in the reciprocal changes of lipoprotein composition.

Electrophysiological and histological abnormalities of the heart in myotonic dystrophy

Abstract For frequent complications of cardiac involvement, it is important to recognize exactly myotonic dystrophy from a cardiovascular standpoint. Electrophysiological and histological studies were performed in three patients. Analysis of the site of the conduction disturbances was revealed by His bundle electrography proximal to the His bundle in one patient and distal in two other patients. The histological examination for biopsied myocardium by light and electron microscopy disclosed replacement of large areas by fat and also showed varying degrees of cellular damage. The most striking abnormality of the heart muscles was found in the mitochondria in which a peculiar and granular substance bulged into the outer space. Both the conduction system and the myocardium were involved in our cases. The value of His bundle recordings and endomyocardial biopsy in evaluating cardiac abnormality in the disease were discussed.

Paroxysmal hypertension in aortitis syndrome.

Three patients with aortitis syndrome ehibited paroxysmal hypertension which seemed to result from baroreceptor dysfunction. All of the patients had signs of active inflammation of aortitis syndrome and stenotic carotid and subclavian arteries. During the attacks, the blood pressure rose to at least 230 mm. Hg systolic and the heart rate exceeded 100. However, with prolonged administration of steroid hormones, the attacks ceased. In two patients with dilated thoracic aortas and aortic regurgitation, the attacks of paroxysmal hypertension occurred without apparent precipitating factors and were followed by anginal pain with marked ST depression. The sympathicotonic state resulting from the disturbance of the baroreceptors was considered to be responsible for the attacks. In another patient, the attacks occurred in the course of treatment with a steroid hormone and were provoked only by voluntary micturition. This post-micturition hypertension was presumed to be an expression of abnormal overshooting following a fall in blood pressure after voiding.

Hypobetalipoproteinemia with abnormal prebetalipoprotein

A 47-year-old man who had cerebellar ataxia and low plasma lipid and lipoprotein levels is reported. His tendon reflexes were hyperactive and the plantar responses were extensor. There was no acanthocytosis. Total lipids (380 mg/dl), total cholesterol (106 mg/dl), esterified cholesterol (74 mg/dl), triglyceride (58 mg/dl), phospholipids (124 mg/dl) and free fatty acids (303 muequiv./l) were generally decreased. A disturbance of lipid absorption due to a defect of chylomicron formation and hepatic steatosis were also disclosed. On lipoprotein electrophoresis, prebetalipoprotein was very faint and migrated more slowly than normal. Betalipoprotein and alphalipoprotein were moderately reduced in concentration but migrated normally. The concentration of isolated VLDL was only one-tenth of that in normal subjects and it migrated as slow prebetalipoprotein. Although the lipid composition of VLDL was similar to that of normal VLDL, the lack of minor components was disclosed by SDS-PAG electrophoresis. Incorporation of [1-14C]acetate into VLDL lipids was significantly reduced to a greater extent than that of LDL and HDL. From these findings, we discuss the possibility that hypobetalipoproteinemia results from impaired VLDL synthesis.