MEASUREMENT OF TOTAL BODY PROTEIN, FAT AND WATER USING IN VIVO NEUTRON ACTIVATION ANALYSIS

简介：已经建立了体内中子活化分析（IVNAA）设施，能够对身体的组成部分进行准确和精确的测量。紧凑的缔合粒子密封管中子发生器（APSTNG）是市售的，并且结果表明，通过测量存在的全身碳、全身氮和全身氧的质量，可以同时测定全身蛋白质、全身脂肪和全身水。方法：APSTNG及其高压控制系统由美国核诊断系统公司提供，（美国弗吉尼亚州斯普林菲尔德）。在距离APSTNG 30 cm处照射样品并计数15分钟。水的化学分析采用冷冻干燥法，脂肪采用石油醚索氏提取法，灰分采用600℃燃烧法，蛋白质采用凯氏定氮法。结果：蛋白质、脂肪和水分的IVNAA测定结果与化学分析结果吻合较好。基于APSTNG可以组装成一种测量体内成分的仪器。它的使用将使在15分钟的扫描内同时测量整个身体中的蛋白质、脂肪和水成为可能。

Introduction : In vivo neutron activation analysis (IVNAA) facilities have been set up enabling accurate and precise measurements to be made of the components of the body. A compact associated particle sealed tube neutron generator (APSTNG) is commercially available arid the results show that total body protein, total body fat, and total body water could be determined simultaneously by measuring the mass of total body carbon, total body nitrogen, and total body oxygen present. Methods : The APSTNG and its high voltage control system were supplied by Nuclear Diagnostic Systems Inc., (Springfield, VA, USA). The samples were irradiated at a distance of 30 cm from the APSTNG and counted for 15 minutes. The chemical analysis of water was performed by freeze drying, fat by soxhlet extraction with petroleum ether, ash by combustion at 600℃ and protein by the Kjeldahl method. Results: There is good agreement between the IVNAA and chemical analysis results for protein, fat and water. Summary An instrument based on the APSTNG for measuring the composition of body in vivo can be assembled. Its use would make possible the simultaneous measurement of protein, fat and water in the whole body to good precision within a 15 minutes scan.