EXPERIMENTAL AND CLINICAL STUDY OF NUTRITION IN STRESS SITUATION --EFFECTS OF BRANCHED CHAIN AMINO ACIDS ON ENERGY AND PROTEIN METABOLISM--

1. 本实验旨在比较两种不同亮氨酸和缬氨酸含量的支链氨基酸营养液在胁迫条件下的效果。方法：采用大鼠盲肠结扎术，术后12小时切除坏死盲肠，建立手术应激模型。在这些程序之后，大鼠给予富含亮氨酸的TPN（1组；45% bcaa, leu: val: ile =2:1:1）或富含缬氨酸的TPN (v组；45% bcaa, val: leu: ile =2:1:1) 30小时。两种TPN制剂均为等热量、等氮（250ml / kg / day, 1kcal / ml, kcal / n =135）。在给药的最后6小时，用ri技术比较亮氨酸和缬氨酸的利用程度。给药<^(14)c > -leu （l组）或<^(14)c > -val （v组）后，测定过期< co_2 >的累积放射性。同时还测量了肝脏和肌肉蛋白质中的放射性。结果：两组<^(14)co_2 >的最终产率均为<^(14)c>放射量的40-44%。在肝脏和肌肉蛋白中，<^(14)c > -leu的放射性水平显著高于<^(14)c > -val。这些结果表明，在应激条件下，亮氨酸与缬氨酸一样被氧化，在蛋白质代谢中起着更重要的作用。临床研究对10例脓毒症患者应用bcaa浓缩液作为全肠外营养氮源（bcaa - tpn）进行代谢及临床疗效观察。bcaa-tpn治疗后，蛋白质分解代谢得到适度抑制，紊乱的氨基酸模式改善至接近正常范围。在表现出脑病临床症状的五名患者中，有三名脓毒性脑病也得到了改善。

1. EXPERIMENTAL STUDYTHE PURPOSE OF THIS STUDY WAS TO COMPARE THE EFFICACIES OF TWO TYPES OF BRANCHED CHAIN AMINO ACID-ENRICHED NUTRIENT SOLUTIONS DIFFERING IN THEIR LEUCINE AND VALINE CONTENTS IN STRESS SITUATION.METHODS: A MODEL OF SURGICAL STRESS WAS PRODUCED BY CECAL LIGATION AND RESECTION OF THE NECROTIC CECUM 12 HOURS LATER IN THE RAT. AFTER THESE PROCEDURES, THE RATS WERE ADMINISTERED LEUCINE-ENRICHED TPN (GROUP L; 45% BCAA, LEU:VAL:ILE=2:1:1) OR VALINE-ENRICHED TPN (GROUP V; 45% BCAA, VAL:LEU:ILE=2:1:1) FOR 30 HOURS. BOTH OF THESE TPN PREPARATIONS WERE ISOCALORIC AND ISONITROGENOUS (250ML/KG/DAY, 1KCAL/ ML, KCAL/N=135). DURING THE LAST 6 HOURS OF THE INFUSION PERIOD, THE EXTENTS OF LEUCINE AND VALINE UTILIZATION WERE COMPARED BY RI TECHNIQUE. AFTER ADMINISTRATION OF <^(14)C> -LEU (GROUP L) OR <^(14)C> -VAL (GROUP V), CUMULATIVE RADIOACTIVITY IN EXPIRED <CO_2> WAS MEASURED. RADIOACTIVITY TAKEN IN LIVER AND MUSCLE PROTEINS WAS ALSO MEASURED.RESULTS: THE FINAL YIELDS OF <^(14)CO_2> IN BOTH GROUPS WERE 40-44% OF ADMINISTERED <^(14)C> RADIOACTIVITY. THE RADIOACTIVITY LEVEL DERIVED FROM <^(14)C> -LEU WAS SIGNIFICANTLY HIGHER THAN THAT FROM <^(14)C> -VAL IN BOTH LIVER AND MUSCLE PROTEINS. THESE RESULTS INDICATE THAT LEUCINE IS AS WELL OXIDIZED AS VALINE AND HAS A MORE IMPORTANT ROLE IN PROTEIN METABOLISM IN STRESS SITUATION.2. CLINICAL STUDYTHE METABOLIC AND CLINICAL EFFECTS OF THE BCAA THERAPY WERE STUDIED IN 10 SEPTIC PATIENTS WHO RECEIVED BCAA ENRICHED SOLUTION AS THE NITROGEN SOURCE OF TOTAL PARENTERAL NUTRITION (BCAA-TPN). MODERATE SUPPRESSION OF THE PROTEIN CATABOLISM AND IMPROVEMENT OF DERANGED AMINO ACID PATTERNS TO NEAR NORMAL RANGE WERE OBSERVED AFTER THE BCAA-TPN THERAPY. SEPTIC ENCEPHALOPATHY WAS ALSO IMPROVED IN THREE OF FIVE PATIENTS WHO HAD SHOWN CLINICAL SIGNS OF ENCEPHALOPATHY.