Sparacino Giovanni, Shames David M, Vicini Paolo, King Janet C, Cobelli Claudio
Department of Electronics and Informatics, University of Padova, 35131 Padua, Italy.
Am J Physiol Endocrinol Metab. 2002 Mar;282(3):E679-87. doi: 10.1152/ajpendo.00113.2001.
Several approaches for estimation of fractional zinc absorption (FZA) by calculating the ratio of oral to intravenous stable isotopic tracer concentrations (at an appropriate time) in urine or plasma after their simultaneous administration have been proposed in the last decade. These simple-to-implement approaches, often referred to as the double isotopic tracer ratio (DITR) method, are more attractive than the classical "deconvolution" method and the more commonly used single-tracer methods based on fecal monitoring and indicator dilution, after oral or intravenous tracer administration, respectively. However, the domain of validity of DITR for measuring FZA has recently been questioned. In this paper, we provide a theoretical justification of the validity of four different "approximate" formulations of the DITR technique by demonstrating mathematically that their accuracy is a consequence of the particular properties of zinc kinetics.
在过去十年中，已经提出了几种通过计算同时给予口服和静脉注射稳定同位素示踪剂后（在适当时间）尿液或血浆中口服与静脉示踪剂浓度之比来估算锌分数吸收（FZA）的方法。这些易于实施的方法，通常称为双同位素示踪剂比率（DITR）法，比经典的“反卷积”法以及分别基于口服或静脉注射示踪剂后粪便监测和指示剂稀释的更常用的单示踪剂方法更具吸引力。然而，DITR测量FZA的有效性范围最近受到了质疑。在本文中，我们通过数学证明四种不同的DITR技术“近似”公式的准确性是锌动力学特定性质的结果，从而为其有效性提供了理论依据。
