CEREBRAL METABOLIC STUDIES BY 1H-13C NMR IN VIVO

该项目将使用新开发的化学特定的、非侵入性的 磁共振波谱方法在脑代谢研究中的应用 人类。将使用1H方法来研究脑衰退的速度 服用低苯丙氨酸的青年苯丙酮尿症患者的苯丙氨酸 在以前选择不遵循这样的饮食习惯后，并 寻找卒中和中风患者脂质降解的证据 痴呆症。将综合使用1H和13C方法来监测 ~(13)C的进入和最终稳定状态~(13)C在氨基中的部分浓缩 给予~(13)C标记葡萄糖时酸池和升高的乳酸池 静脉注射。氨基酸标记的变异范围及最佳选择 1-13C-葡萄糖输注计划将在正常受试者中确定 不同的年龄和体重，在安静清醒时，然后在感官期间 刺激以及痴呆症和复杂的部分性癫痫患者。 中风引起的脑乳酸升高将被研究以评估其稳定性 作为缺血半暗带的一种测量，状态13C的部分浓集。 这一结果有望提供有关正常大脑的新信息 新陈代谢和关于病理生理过程是如何在 痴呆症、中风和癫痫会影响葡萄糖进入大脑的速率 大脑、升高的乳酸代谢活性和氨基率 酸周转。

This project will use newly developed chemically specific, non-invasive magnetic resonance spectroscopic methods to study cerebral metabolism in humans. 1H methods will be used to study the rate of decline of brain phenylalanine in young adult phenylketonurics who go on a low-phenylalanine diet after having chosen previously not to follow such a diet, and to search for evidence of lipid degradation in patients with stroke and dementia. Combined 1H and 13C methods will be used to monitor rates of entry of 13C and eventual steady state 13C fractional enrichment in amino acid and elevated lactate pools when 13C-labeled glucose is given intravenously. The range of variation of amino acid labeling and optimum 1-13C-glucose infusion schedules will be determined in normal subjects of varying age and weight during quiet wakefulness, and then during sensory stimulation and in patients with dementia and complex partial epilepsy. Cerebral lactate elevated by stroke will be studied to evaluate it steady state 13C fractional enrichment as a measure of an ischemic penumbra. The results are expected to provide new information about normal cerebral metabolism and about how the pathophysiological processes at work in dementia, stroke, and epilepsy affect the rate of glucose entry into the brain, the metabolic activity of elevated lactate pools, and rates of amino acid turnover.