Masahiko Akanuma

Coronary remodeling of proximal and distal stenotic atherosclerotic plaques within the same artery by intravascular ultrasound study

The aim of this intravascular ultrasound study was to compare the type and the degree of vessel remodeling in proximal and distal de novo lesions within the same coronary artery in patients with stable angina pectoris. Seventy-six de novo coronary artery lesions in 38 coronary arteries of 38 patients were imaged by intravascular ultrasound. The vessel area (VA) within the external elastic lamina and the lumen area (LA) were measured, and the wall area (VA-LA) was calculated at the lesion site, and the proximal and distal reference sites. The VA ratio was defined as (lesion VA/average of the proximal and distal reference VAs) to represent the degree of vessel remodeling. The proximal coronary segments showed compensatory enlargement more often (68% vs 29%, p < 0.01) than the distal segments, and the VA ratio at the lesion site was significantly larger (1.1 +/- 0.3 vs 1.0 +/- 0.2, p <0 .01) in proximal segments than in distal segments. The type of coronary remodeling was discordant in 61% and concordant in only 39% of coronary arteries between the proximal and distal segments. The type of coronary remodeling of proximal and distal coronary lesions was inhomogeneous, even within the same vessel. Proximal coronary segments showed more prominent compensatory enlargement than distal segments, which have a similar degree of luminal narrowings.

Hypertrophic obstructive cardiomyopathy due to a novel T-to-A transition at codon 624 in the β-myosin heavy chain (β-MHC) gene possibly related to the sudden death

Many missense mutations in the beta-myosin heavy chain have been reported in patients with hypertrophic obstructive cardiomyopathy (HOCM). However, the controversy is present whether the mutation accompanying the change of electric charge is related with poorer prognosis. The proband, a 48-year-old female, of the family was diagnosed clinically as HOCM, and a structural analysis of the cardiac beta-MHC gene showed that the proband and her junior daughter had a novel mutation with T to A transition in codon 624 replacing tyrosine with asparagine, which was not present in her husband, elder daughter and son. The probands husband, son and two daughters were healthy except that the ECG of junior daughter (15-year-old) showed complete right bundle branch block. Probands mother died suddenly after the delivery of the proband and the proband also collapsed suddenly. The occurrence of sudden death in proband and her mother suggested that HOCM with this novel mutation might be associated with a high risk of sudden death irrespective of the absence of charge alteration.

ENHANCED BETA‐ADRENERGIC SIGNAL TRANSDUCTION IN SPONTANEOUSLY HYPERTENSIVE RATS

The p-adrenergic system is thought to play an important role in the onset of hypertension and the adjustment of the heart to a hypertensive state. The padrenergic system mediates the powerful, positive inotropic effects of adrenergic stimuli, producing CAMP which enhances myocardial contractility. Thus alteration in the P-adrenergic system may be a major cause of impaired myocardium and may influence the progression of heart failure resulting from prolonged hypertension. However, the biochemical mechanisms underlying these pathological disorders, collectively termed ‘hypertensive heart’, are unclear, and reports of changes in ,&receptors in the heart of spontaneously hypertensive rats (SHR) are variable (Limas & Limas 1978; Mochizuki et al. 1984). This study is designed to clarify the changes in the signal transduction of the p-adrenergic system (padrenergic receptor-GTP bound stimulatory protein (Gs)-adenylate cyclase) in hypertensive hearts, using the myocardium of SHR as a genetic model of essential hypertension. METHODS

[Clinical, pathological and immunohistological features of a case of localized nodular myopathy].

31才,男性. 3年前から再燃を繰り返す大腿部に限局する硬結と疼痛を認めた.検査上,血沈亢進とCRP陽性を認め,筋生検により,リンパ球浸潤, snake coil fiber, whorled fiberなどのinflammatory myopathyの所見を持ち, Gummingらによるlocalized nodularmyositisと診断された.ステロイド投与により軽快するも再燃を繰り返した.本例は,リンパ球浸潤の分布, TBリンパ球の出現比率, Tリンパ球のsubsetの出現比率において皮膚筋炎と同様の像を呈していた.本例は, localized nodular myositisの疾患概念を確立する上に貴重な症例と思われた.