IN VIVO NMR METABOLIC STUDY OF REGIONAL CARDIAC ISCHEMIA

心肌收缩功能是一种常用的 细胞活力 然而，机械功能可能是一种 由于未能恢复，细胞活力指数不足 缺血和再灌注后的收缩功能 与细胞死亡同义。 化合物的改变 氧化或厌氧代谢可能更能指示细胞 心脏维持或恢复的能力 机械功能 高能磷酸盐储存的损失或 在无氧代谢过程中乳酸盐的积累已经 与缺血诱导的心肌功能障碍有关。 它 将是理想的，以确定这些序列的体内变化， 在心肌缺血期间和之后的化合物， 评估这些化合物是否可用于预测 缺血后收缩功能障碍 直到最近， 心肌组织是必要的，以评估代谢 氧化和无氧代谢的产物。 最近 核磁共振技术进展 光谱学现在允许测量这些化合物， 连续的、非破坏性的方式在体内。 此前 区域力学测量的常规方法 在动物中的功能利用了渡越时间技术， 需要两个超声波晶体;一个缝合到心外膜 另一个则嵌入了动脉内膜下。 本程序 造成相当大的创伤和维护困难 在实验过程中两个晶体的排列。 一个新 发展了心外膜多普勒超声晶体技术， 克服这些局限性，并允许评估分段 以非创伤性、非侵入性的方式检测心肌收缩力。 因此，使用NMR技术结合心外膜 多普勒测量机械功能，一种独特的方法 用于体内代谢和机械的快速连续测量 心肌缺血和再灌注时发生的变化是 可能 我们建议利用这些技术来确定 高能磷酸盐在体心脏动态变化 化合物和乳酸盐， 这些变化与心肌收缩力的变化 以确定这些化合物中的一种是否可以用来预测 逆转缺血后心肌功能障碍。 与 出现在体内核磁共振技术适用于人，这项工作 可用于评估心脏代谢的变化， 干预后可能发生的机械功能 旨在限制心肌缺血。

Myocardial contractile function is a commonly used marker of cell viability. However, mechanical function may be an inadequate index of cell viability since failure to recover contractile function following ischemia and reperfusion is not synonymous with cell death. Alterations in compounds of oxidative or anaerobic metabolism may be more indicative of cell viability and the ability of the heart to maintain or recover mechanical function. The loss of high energy phosphate stores or accumulation of lactate during anaerobic metabolism has been associated with ischemia induced myocardial dysfunction. It would be ideal to determine the serial in vivo changes of these compounds during and following myocardial ischemia in order to assess if these compounds may be used to predict reversibility of postischemic contractile dysfunction. Until recently, biopsies of myocardial tissue were necessary to evaluate the metabolic products of oxidative and anaerobic metabolism. Recent technological advances in nuclear magnetic resonance (NMR) spectroscopy now allow measurements of these compounds in a serial , nondestructive manner in vivo. Previously, the conventional method for measurement of regional mechanical function in animals utilized the transit-time technique which required tow ultrasound crystals; one sutured to the epicardium and the other imbedded into the subendocardium. This procedure caused considerable trauma and difficulty in maintaining alignment of the two crystals during an experiment. A newly developed epicardial Doppler ultrasound crystal technique has overcome these limitations and allows assessment of segmental myocardial contractility in a nontraumatic, noninvasive manner. Thus, using NMR techniques in conjunction with epicardial Doppler measurements of mechanical function, a unique method for rapid serial for vivo measurements metabolic and mechanical changes that occur with myocardial ischemia and reperfusion is possible. We propose to utilize these techniques to determine serially in vivo cardiac changes of high energy phosphate compounds and lactate during and following ischemia and relate these changes to the changes in myocardial contractility in order to determine if one of these compounds can be used to predict reversal of post-ischemic myocardial dysfunction. With the advent of in vivo NMR techniques applicable to man, this work may be useful in assessing the changes of cardiac metabolism and mechanical function that may occur following interventions designed to limit myocardial ischemia.