Sheng Xiao-Yang, Hambidge K Michael, Krebs Nancy F, Lei Sian, Westcott Jamie E, Miller Leland V
Section of Nutrition, Department of Pediatrics, University of Colorado Health Sciences Center, Denver, CO 80262, USA.
Am J Clin Nutr. 2005 Nov;82(5):1017-23. doi: 10.1093/ajcn/82.5.1017.
Dysprosium is a nonabsorbable rare earth element that has had successful application as a marker for fecal excretion of unabsorbed zinc.
Our goals were 1) to evaluate the efficacy of administering dysprosium with all meals over several days as a method of determining the completeness of fecal collections, 2) to determine the similarity of gastrointestinal transit kinetics and excretion patterns of dysprosium and zinc tracer administered simultaneously over several days, and 3) to evaluate alternative methods of using the data for fecal excretion of orally administered zinc tracer and dysprosium to measure the fractional absorption of zinc.
70Zn and dysprosium were administered orally with all meals for 5 consecutive days to 7 healthy, free-living adults consuming a constant diet based on habitual intake. Additional tracers, 67Zn and 68Zn, were administered intravenously. Urine and fecal samples were collected during tracer administration and for 8 d after the last dose. Isotope ratios were measured in urine and feces, and total zinc and dysprosium were measured in fecal samples.
The mean recovery of dysprosium was 101.3 +/- 2.4%. The zinc oral tracer and dysprosium had similar fecal excretory patterns; the correlation coefficient for 70Zn and dysprosium in fecal samples exceeded 0.99 (P < 0.0001) for each subject. Fractional zinc absorption measurements using various dysprosium methods correlated well (r > 0.95) with those from the fecal monitoring and dual-isotope-tracer ratio methods.
Administration of dysprosium is a useful means of determining the completeness of fecal collections and of measuring zinc absorption.
镝是一种不可吸收的稀土元素，已成功用作未吸收锌粪便排泄的标志物。
我们的目标是：1）评估连续数天每餐服用镝作为确定粪便收集完整性的方法的有效性；2）确定连续数天同时服用的镝和锌示踪剂的胃肠转运动力学和排泄模式的相似性；3）评估使用口服锌示踪剂和镝的粪便排泄数据来测量锌的吸收分数的替代方法。
连续5天，让7名健康、自由生活且饮食基于习惯摄入量保持恒定的成年人每餐口服70Zn和镝。另外静脉注射67Zn和68Zn示踪剂。在示踪剂给药期间以及最后一剂后8天收集尿液和粪便样本。测量尿液和粪便中的同位素比率，并测量粪便样本中的总锌和镝含量。
镝的平均回收率为101.3±2.4%。锌口服示踪剂和镝具有相似的粪便排泄模式；每个受试者粪便样本中70Zn和镝的相关系数超过0.99（P<0.0001）。使用各种镝方法测量的锌吸收分数与粪便监测和双同位素示踪剂比率方法测量的结果相关性良好（r>0.95）。
服用镝是确定粪便收集完整性和测量锌吸收的有用方法。
