School of Health Sciences, Purdue University, West Lafayette, IN, United States of America.
Physiol Meas. 2019 Aug 2;40(7):075009. doi: 10.1088/1361-6579/ab2ba5.
The locations of sodium (Na) storage and its exchange mechanisms in the body are not well known. Understanding tissue Na storage and exchange is important for understanding the impact of Na intake, absorption, and retention on human health, especially on the risk of developing chronic diseases. The purpose of this study was to investigate the application of a deuterium-deuterium (DD) neutron generator-based IVNAA system in Na nutrition studies.
The right legs of two live pigs, one on a low Na diet and one on a high Na diet, both for 14 d, were irradiated inside a customized irradiation cave for 10 min (45 mSv dose to the leg) and then measured with a 100% efficient high purity germanium detector (HPGe). The spectra were analyzed to obtain the net Na counts at different time points. Bone Na concentrations were calculated using the calibration created with Na bone phantoms.
The results show that the difference in bone Na to calcium between the pigs on high versus low Na diets was 466 ± 137 ppm. The estimated bone Na to calcium concentrations were 1166 ± 80 and 1631 ± 111 ppm for low and high Na diet pigs, respectively. Analysis also shows rapid exchange of Na in the leg during the first 2 h measurements, while the exchange was minimal at the second and third 2 h measurements, taken 7 and 21 h post irradiation. The exchange decay time of Na in the leg was 51 min for the first measurement, and there was no significant change of Na activities between 2-21 h.
With these results, we conclude there is a non or low exchangeable compartment (likely to be bone) for Na storage and that DD neutron generator-based IVNAA is a useful method for determining tissue Na distribution in nutrition studies.
人体中钠（Na）储存的位置及其交换机制尚不清楚。了解组织 Na 的储存和交换对于理解 Na 摄入、吸收和保留对人体健康的影响，特别是对慢性病风险的影响非常重要。本研究旨在探讨基于氘氘（DD）中子发生器的 IVNAA 系统在 Na 营养研究中的应用。
将两只活猪的右腿分别置于低 Na 饮食和高 Na 饮食 14 天后，置于定制的照射洞穴内照射 10 分钟（腿部 45 mSv 剂量），然后用 100%高效高纯锗探测器（HPGe）进行测量。分析谱图以获得不同时间点的净 Na 计数。使用 Na 骨体模创建的校准来计算骨 Na 浓度。
结果表明，高 Na 饮食和低 Na 饮食猪的骨 Na 与钙的差异为 466 ± 137 ppm。估计的骨 Na 与钙浓度分别为 1166 ± 80 和 1631 ± 111 ppm，分别为低和高 Na 饮食猪。分析还表明，腿部 Na 在最初的 2 小时测量中快速交换，而在第二次和第三次 2 小时测量中交换最小，分别在照射后 7 和 21 小时进行。腿部 Na 的交换衰减时间为第一次测量的 51 分钟，2-21 小时之间 Na 活性没有明显变化。
有了这些结果，我们得出结论，Na 储存存在非或低可交换隔室（可能是骨），并且基于 DD 中子发生器的 IVNAA 是一种用于确定营养研究中组织 Na 分布的有用方法。
