Speakman J R, Racey P A
J Appl Physiol (1985). 1986 Sep;61(3):1200-2. doi: 10.1152/jappl.1986.61.3.1200.
Recent applications of the doubly labeled water technique to the study of human metabolism have employed multiple sampling of body water over protracted periods, rather than the more traditional method of taking only an initial and final sample for isotopic analysis. In addition fractional turnovers of the body pools have been estimated by fitting curves to the sequential log-converted isotope enrichment against time. By manipulation of data collected in the field in a study of metabolism of vespertilionid bats, it is shown the curve-fitting technique results in an accurate estimate of CO2 production only when the rate of CO2 production is constant. Biologically realistic nonsteady-state conditions result in errors in estimates of CO2 production of up to 30%. In conditions where CO2 production is known to be temporally variable, the more traditional two-sample method may provide a more accurate estimate of CO2 production.
双标记水技术在人体代谢研究中的最新应用采用了在较长时间内对身体水分进行多次采样，而不是更传统的仅采集初始和最终样本进行同位素分析的方法。此外，通过将连续对数转换后的同位素富集度随时间的曲线拟合来估计身体池的分数周转率。通过对在一项关于蝙蝠代谢的野外研究中收集的数据进行处理，结果表明，只有当二氧化碳产生速率恒定时，曲线拟合技术才能准确估计二氧化碳的产生量。生物学上现实的非稳态条件会导致二氧化碳产生量估计误差高达30%。在已知二氧化碳产生量随时间变化的情况下，更传统的双样本方法可能会提供更准确的二氧化碳产生量估计。
