Evaluation of early treatments for acute myocardial infarction: Basic and co-operative studies

1.研究小组的策略：在日本的10个机构进行了急性心肌梗死早期治疗的有效性和变化机制的实验研究。该小组的研究项目既包括关于再灌注对心肌坏死组织挽救作用的合作研究，也包括与心肌缺血有关的独立研究。本研究的目的是：1)阐明决定心肌缺血后不可逆性损伤的因素；2)获得敏感的反映心肌可逆性改变的有用指标；3)建立减少心肌坏死的治疗方法。心肌缺血或低氧血症时体内能量代谢变化的核磁共振波谱分析及早期细胞内pH的变化(Imai，Hosoda)。应用二维超声心动图(Yazaki)、心动图(Tamura)、电生理学(Sugimoto)和植入式pH传感器(Abiko)观察再灌注对冠脉阻断3h后局部室壁运动、致死性心律失常发生率和心肌内pH的影响。在犬模型中，再灌注组在冠状动脉闭塞90分钟后24小时(Nakamura M)而不是3小时(Nakamura Y)显示出显著的组织挽救作用。柴田证明了脂氧合酶拮抗剂在组织挽救抗再灌注损伤中的一些有益作用。

1. Strateqies of the research group; Effectiveness and salutatory mechanism of the early treatment of acute myocardial infarction were studied experimentally in 10 institutions in Japan. The research projects of the group were constituted from both a cooperative study on the effects of reperfusion for tissue salvage from myocardial necrosis and independent studies relating to myocardial ischemia. The goal of the present study was 1) to elucidate the factors which determine the irreversible damage of the myocardium after ischemic insult, 2) to derive useful indexes representing sensitively the alterations of myocardial reversibility and 3) to establish the remedies to reduce myocardial necrosis.2. Co-operative study on the effects of reperfusion on ischemic myocardium ; Alterations of energy metabolism in vivo during myocardial ischemia or hypoxemia were determined spectrologically by NMR and early changes of intracellular pH were demonstrated (Imai, Hosoda). Effects of reperfusion on regional wall motion, incidnce of fatal arrhythmia, and intramyocardial pH after 3 hours of coronary occlusion were examined in anesthetized canine model using two dimensional echocardiography (Yazaki) or cardiomovegraphy (Tamura), electrophysiology (Sugimoto) and implantable pH sensors (Abiko), in which the level of wall motion and the size of myocardial necrosis or the amount of myosin light-chain kinase released was discordant early after reperfusion. A significant tissue salvage in a reperfusion group 24 hours after 90 minutes (Nakamura M) but not 3 hours (Nakamura Y) of coronary occlusion was demonstrated in a canine model. Shibata demonstrated some beneficial effects of a lipoxigenase antagonist on tissue salvage against reperfusion damage.