IN VIVO NMR METABOLIC STUDY OF REGIONAL CARDIAC ISCHEMIA

心肌收缩功能是一项常用的指标。 细胞存活率。然而，机械功能可能是 自未能恢复以来，细胞活力指标不足 缺血再灌流后的收缩功能不是 是细胞死亡的代名词。化合物中的变化 氧化或无氧代谢可能更能反映细胞 心脏的生存能力和维持或恢复的能力 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的积累 与缺血引起的心肌功能障碍有关。它 将是确定这些基因在体内的一系列变化的理想方法 在心肌缺血期间和之后的化合物，以便 评估这些化合物是否可用于预测心脏可逆性 缺血后收缩功能障碍。直到最近，活组织检查 心肌组织是评估代谢所必需的。 氧化和厌氧代谢的产物。近期 核磁共振技术进展 光谱学现在允许测量这些化合物在一个 在体内以连续的、非破坏性的方式。此前， 区域力学测量的常规方法 动物的功能利用了穿越时间技术，这种技术 需要两个超声晶体；一个缝合在心外膜上 另一枚植入心内膜下。此过程 造成了相当大的创伤和维护困难 在一次实验中两个晶体的排列。一个新的 开发的心外膜多普勒超声晶体技术已经 克服这些限制，并允许评估分段 非创伤性、非侵入性的心肌收缩能力。 因此，结合使用核磁共振技术和心外膜 机械功能的多普勒测量--一种独特的方法 用于体内代谢和机械测量的快速连续测量 心肌缺血和再灌流引起的变化是 有可能。我们建议利用这些技术来确定 高能磷酸盐在体心脏的动态变化 缺血时和缺血后的化合物和乳酸及其关系 这些变化依次为心肌收缩能力的变化 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 活体核磁共振技术的问世适用于人类，这项工作 可用于评估心脏代谢的变化和 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.