Yergey A L, Abrams S A, Vieira N E, Aldroubi A, Marini J, Sidbury J B
National Institute of Child Health and Human Development, Bethesda, MD 20892.
J Nutr. 1994 May;124(5):674-82. doi: 10.1093/jn/124.5.674.
Four dual-isotopic label methods for determining true fractional absorption of dietary calcium were compared in 23 subjects. The ratio of the integrals of oral label in a 24-h pooled urine to intravenous label in the same urine is called alpha 24h and was taken as the standard against which the others were compared. alpha Spot is the ratio of the fraction of oral label to the fraction of intravenous label in a single urine specimen; alpha Lag is the ratio of the level of oral label in blood 4 h after administration to the level of intravenous label in blood 2 h after administration. alpha Dec is obtained by deconvoluting response to the intravenous label from the response to the oral tracer. Results were as follows: alpha 24h = 0.273 +/- 0.124, alpha Dec = 0.300 +/- 0.101 (n = 14), alpha Spot = 0.359 +/- 0.179, and alpha Lag = 0.271 +/- 0.103. The Bland-Altman approach for comparison of methods was used to show that results for alpha Spot and alpha Lag can be expected, with a 95% confidence limit, to differ from the value of alpha 24h by 60 and 69%, respectively. The results for alpha Dec were shown to be not only indistinguishable from alpha 24h but identical from a theoretical perspective.
在23名受试者中比较了四种用于测定膳食钙真实吸收分数的双同位素标记方法。24小时混合尿中口服标记物积分与同一尿液中静脉注射标记物积分的比值称为α24h，并将其作为与其他方法进行比较的标准。αSpot是单个尿液标本中口服标记物分数与静脉注射标记物分数的比值；αLag是给药后4小时血液中口服标记物水平与给药后2小时血液中静脉注射标记物水平的比值。αDec是通过从口服示踪剂的反应中反卷积出对静脉注射标记物的反应而获得的。结果如下：α24h = 0.273±0.124，αDec = 0.300±0.101（n = 14），αSpot = 0.359±0.179，αLag = 0.271±0.103。采用Bland-Altman方法比较方法，结果表明，αSpot和αLag的结果，在95%置信限下，预计分别与α24h的值相差60%和69%。结果表明，αDec的结果不仅与α24h无法区分，而且从理论角度来看是相同的。
