Departments of Nutrition, University of California, Davis, Davis, California 95616, USA.
J Agric Food Chem. 2010 Apr 28;58(8):4632-7. doi: 10.1021/jf100113c.
(14)C has long been used as a tracer for quantifying the in vivo human metabolism of food components, biopharmaceuticals, and nutrients. Minute amounts (< or =1 x 10 (-18) mol) of (14)C can be measured with high-throughput (14)C-accelerator mass spectrometry (HT (14)C-AMS) in isolated chemical extracts of biological, biomedical, and environmental samples. Availability of in vivo human data sets using a (14)C tracer would enable current concepts of the metabolic behavior of food components, biopharmaceuticals, or nutrients to be organized into models suitable for quantitative hypothesis testing and determination of metabolic parameters. In vivo models are important for specification of intake levels for food components, biopharmaceuticals, and nutrients. Accurate estimation of the radiation exposure from ingested (14)C is an essential component of the experimental design. Therefore, this paper illustrates the calculation involved in determining the radiation exposure from a minute dose of orally administered (14)C-beta-carotene, (14)C-alpha-tocopherol, (14)C-lutein, and (14)C-folic acid from four prior experiments. The administered doses ranged from 36 to 100 nCi, and radiation exposure ranged from 0.12 to 5.2 microSv to whole body and from 0.2 to 3.4 microSv to liver with consideration of tissue weighting factor and fractional nutrient. In comparison, radiation exposure experienced during a 4 h airline flight across the United States at 37000 ft was 20 microSv.
(14)C 长期以来一直被用作示踪剂，用于定量测定食物成分、生物制药和营养素在人体中的代谢情况。通过高通量 (14)C-加速器质谱 (HT (14)C-AMS)，可以从生物、生物医学和环境样本的分离化学提取物中测量低至 1 x 10 (-18) mol 的 (14)C 量。使用 (14)C 示踪剂获得的人体体内数据将使食物成分、生物制药或营养素的代谢行为的现有概念能够组织成适合定量假设检验和确定代谢参数的模型。体内模型对于规定食物成分、生物制药和营养素的摄入量水平很重要。准确估计摄入 (14)C 引起的辐射暴露是实验设计的重要组成部分。因此，本文说明了从四个先前实验中口服给予的微量 (14)C-β-胡萝卜素、(14)C-α-生育酚、(14)C-叶黄素和 (14)C-叶酸的辐射暴露的计算过程。给予的剂量范围为 36 至 100 nCi，辐射暴露范围为 0.12 至 5.2 微 Sv 至全身，0.2 至 3.4 微 Sv 至肝脏，同时考虑了组织权重因子和营养素分数。相比之下，在美国 37000 英尺高空的 4 小时航班飞行期间经历的辐射暴露为 20 微 Sv。
