Klein P D, James W P, Wong W W, Irving C S, Murgatroyd P R, Cabrera M, Dallosso H M, Klein E R, Nichols B L
Hum Nutr Clin Nutr. 1984 Mar;38(2):95-106.
The turnover rates of water and carbon dioxide have been estimated at frequent intervals after a single dose of 2H2 18O had been given to an adult monitored continuously in a whole body calorimeter for 5 d. The integrated CO2 production rate for 5 d, estimated from the differential rates of 2H and 18O excretion in urine, was within 2 per cent of the actual CO2 output, based on an improved method of calculation. Changes occurred in the abundance of 2H and 18O in response to activity, so that the timing of samples was important. It was found better to compute the production rate of CO2 from multiple samples rather than from measurements at only two points of time. The proportion of total water lost by evaporation proved to be less than previously assumed. Direct validation of the technique requires calorimetric studies of 2 to 3 weeks duration, in either animals or human subjects. The potential value of this method for measurement of energy expenditure in man is such that exacting tests of its accuracy and precision are needed before it is adopted for general use in metabolic and epidemiological studies.
给一名成年受试者单次静脉注射2H2 18O后，将其置于全身热量计中连续监测5天，期间频繁测定水和二氧化碳的转换率。根据尿液中2H和18O排泄的差异率估算的5天累计二氧化碳产生率，基于一种改进的计算方法，与实际二氧化碳输出量的误差在2%以内。2H和18O的丰度会随活动而变化，因此采样时间很重要。结果发现，通过多个样本计算二氧化碳产生率比仅在两个时间点测量更好。事实证明，蒸发损失的总水量比例低于先前的假设。该技术的直接验证需要在动物或人类受试者中进行持续2至3周的热量测定研究。这种测量人体能量消耗方法的潜在价值很高，因此在将其用于代谢和流行病学研究之前，需要对其准确性和精密度进行严格测试。
