Kouji Imataka

Cellular and molecular bases for the immunopathology of the myocardial cell damage involved in acute viral myocarditis with special reference to dilated cardiomyopathy

Cell-mediated autoimmunity has been strongly implicated in the pathogenesis of the myocardial cell damage involved in viral myocarditis. To investigate the cellular and molecular bases of both target cells and effector cells for cell-mediated cytotoxicity involved in viral myocarditis and dilated cardiomyopathy, we first examined the expression of major histocompatibility complex (MHC) antigens and a cell adhesion molecule, intercellular adhesion molecule-1 (ICAM-1) in myocardial cells of a murine model of viral myocarditis and in patients with acute myocarditis and dilated cardiomyopathy. Secondly, we analyzed the characteristics of the infiltrating cells in the heart, especially the expression of a cytolytic factor, perforin. We found that Coxsackievirus B3 (CVB3)-induced murine acute myocarditis resulted in enhanced expression of MHC (class I) antigens and ICAM-1 on myocardial cells, and that perforin was abundantly expressed in NK (natural killer)-like large granular lymphocytes (LGL), which represent the main infiltrating cell type in the early stage. Immunoelectron microscopic study showed killer cells directly damaging cardiac myocytes by the release of perforin. Perforin was also expressed in the infiltrating cells in the heart of a patient with acute myocarditis. Both MHC antigens and ICAM-1 were clearly expressed in the hearts of patients with acute myocarditis and dilated cardiomyopathy. These data provided direct evidence that cell-mediated cytotoxicity plays a critical role in the myocardial cell damage involved in viral myocarditis.

Atrial natriuretic peptide with artificial pacemakers

Abstract Accumulating evidence indicates that atrial natriuretic peptide (ANP) is a circulating hormone in humans. 1–4 Plasma levels of ANP increase in patients with various heart diseases such as paroxysmal atrial arrhythmias 2 and congestive heart failure. 3,4 If atrial stretching due to increased atrial pressure stimulates ANP secretion, 4 plasma ANP levels may be altered in patients with bradyarrhythmias and in those with pacemaker syndrome, a major clinical complication in patients in whom artificial pacemakers are implanted. 5 To clarify the role of ANP in the pathophysiology of these states, we examined plasma ANP levels in patients with bradyarrhythmias and in those treated with pacemakers of various modes.

A new model for infective endocarditis of the mitral valve in rabbits

To produce an experimental model of infective endocarditis without inserting catheters into the heart, we injected a bacterial suspension into rabbits in which mitral complex lesions had been induced by electrical stimulation of the cervical vagus. Typical infective vegetations grew on the surface of the mitral valves 1 week later. The formation of vegetations was related to the timing of the inoculation. Streptococcus viridans injected just after vagal stimulation produced vegetations in 10 of 17 animals (58.8%), but the same bacteria injected 14 days after vagal stimulation did so in only 2 of 11 animals (18.2%). The incidence of infective endocarditis was significantly higher after early inoculation compared with delayed inoculation (p < 0.01). The susceptibility to infection depended on the species of bacteria injected. Both S. viridans and Pseudomonas pseudoalkaligenes injected just after vagal stimulation produced vegetations in 10 of 17 (58.8%) and 6 of 13 (46.2%) animals, respectively, but Staphylococcus epidermidis injected just after vagal stimulation did not produce vegetations in any of the 10 animals. S. viridans injected into nine normal animals never produced vegetations. These findings indicate that infective endocarditis develops after intravenous injection of bacterial suspensions alone in rabbits with mitral complex lesions.

Calcification of the Carotid Arteries, a Clinical Sign of Severe Generalized Atherosclerosis

X線写真上の頚動脈石灰化像に関し, 40歳以上983例 (男619例, 女364例) について検討した. 頚動脈石灰化は40歳代では男90例, 女46例中で1例も認められなかった. 50歳代では男168例中2例 (1.2%),女128例中3例 (2.3%), 60歳代では男233例中45例 (19.3%), 女130例中5例 (3.8%), 70歳代では男128例中35例 (27.3%), 女60例中10例 (16.7%) に認められ, 60歳以降急速に出現頻度が高まった. 60歳代では男に有意に高頻度であり (p<0.001), 70歳代でもその傾向は認められた. 頚動脈石灰化例では高血圧, 耐糖能低下, 脳卒中の合併率も高く, また大動脈弓部あるいは腹部大動脈石灰化の合併も高率であった. これらより, 頚動脈石灰化は高度な全身性動脈硬化の存在を示唆する重要な所見と考えられた.

Hydroxyproline in all parts of the rabbit heart in hypertension and in its reversal

To investigate the response of cardiac collagen to arterial hypertension and its reversal, we measured the hydroxyproline concentration in all parts of the rabbit heart in three groups: a chronic hypertension group (n = 11), a reversal group (n = 9) and an age-matched control group (n = 10). Left ventricular overload was produced by one-kidney, one-clip Goldblatt hypertension and its reversal was produced by clip release. The wet weight of every part of the left side of the heart was increased by hypertension and all parts except for the papillary muscles showed regression with reversal. However, the response of collagen was quite different among the various parts of the heart. The wet weights of the left atrium, left ventricular free wall, interventricular septum, and anterior and posterior papillary muscle in the hypertension group were 144 (P less than 0.01), 140 (P less than 0.01), 134 (P less than 0.01), 144 (P less than 0.01) and 129% (P less than 0.01), respectively, and those in the reversal group were 92, 113 (P less than 0.05), 107 (P less than 0.05), 142 (P less than 0.05) and 126% (P less than 0.05) of those in the control group, respectively. Hydroxyproline concentrations in the respective parts in the hypertension group were 79 (P less than 0.05), 91, 98, 121 (P less than 0.05) and 120% (P less than 0.05) and those in the reversal group were 86, 93, 94, 107 and 110% of those in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

THE EFFECT OF CHANGES OF BODY POSITION ON THE STANDARD LEAD ELECTROCARDIOGRAM

心筋硬塞を除いた30～84才の100例(男64例,女36例)につき,仰臥位,右側臥位,左側臥位,坐位における呼気時の標準12誘導心電図の記録を行ない,仰臥位との比較検討を行なつた. 20例につき胸部誘導のR波の高さを測定し,仰臥位の高さを100%とすると,左側臥位におけるRv6の変化が最大であり,平均204%となつた.そこでRv6の体位による変化を, 100例について同様の方法にて検討したところ,右側臥位で100.6±20.0% (標準偏差),左側臥位で180.1±56.3%,坐位で94.8±19.4%の変化を示し,左側臥位では150%以上となつたものが74例あり,最も大きな変化を示した. Tv6についても同様にして検討すると,右側臥位で94.3±40.1%,左側臥位で160.2±61.3%,坐位で93.6±33.5%の変化を示した.左側臥位でのRv6の変化とTv6の変化との間には有意の相関がみられたが,相関係数は+0.31と小さかつた.心電図記録と同条件下で撮影した胸部X線写真で体位による心臓の偏位の程度,並びに左横隔膜の高さの変化の程度とRv6の変化の程度とを比較したが,有意の相関はみられなかつた.体位変換によりT波の逆転したもの8例, STの著明に変化したもの2例があつた.移行帯は体位交換では変化しないものが多かつた.平均電気軸は,右側臥位,左側臥位では右方に,坐位では左方に動くものが多かつた.

Sex Difference of Aortic Calcification

1969年～1978年の間に, 当院を受診した. 40歳代～70歳代の男性1,828例, 女性1,093例を対象として, 大動脈石灰化像の年代別, 部位別の性差について検討を行った. 石灰化像はルーチンの胸部背腹方向と, 腰椎側方向のX線写真にて判定した.大動脈石灰化像を, 大動脈弓部, 腹部大動脈, 及びその両者にあるものを, 一括してみると, 各年代ともその出現頻度に男女差はみられなかった. しかし, 大動脈弓部と腹部大動脈を別々にみると, 大動脈弓部では, 各年代とも女性の方が高い出現頻度を示し, 60歳代, 70歳代, 及び全例の合計において, 男女の間に有意差があった. 腹部大動脈では, 各年代とも男性の方が高い出現頻度を示し, 40歳代, 50歳代, 及び全例の合計において有意差がみられた. 石灰化像の認められたものだけについて, 大動脈弓部のみ, 腹部大動脈のみ, 及びその両者ともに石灰化のあるものの3群に分けると, 男性では, 女性に比し, 腹部石灰化の割合が高く, 女性では男性に比し, 弓部石灰化の割合が高く, 70歳代以外では, すべて有意差がみられた.