Rüfenacht H S, Fleisch H
Am J Physiol. 1984 May;246(5 Pt 2):F648-55. doi: 10.1152/ajprenal.1984.246.5.F648.
Two methods are described to measure quantitatively the inhibitory activity of calcium phosphate precipitation in undiluted plasma ultrafiltrates. The first, called the "seed test," is based on the determination of the amount of apatite needed to induce the precipitation of calcium phosphate from the ultrafiltrate that previously had been brought to a constant [Ca X Pi] supersaturation. The second, called the "supersaturation test," is based on the determination of the minimum [Ca X Pi] product necessary to induce the precipitation of calcium phosphate, care being taken to eliminate the influence of chelators. With both techniques pyrophosphate was found to be the most effective inhibitor, magnesium and citrate being less active. At the physiological concentrations present in plasma ultrafiltrate, magnesium represented the greatest part of the activity in the seed test, while pyrophosphate was the most important in the supersaturation test. However, the three known inhibitors represented only part of the total inhibitory activity. In a pilot study, patients with renal failure showed an increase in inhibitory activity both in the known and unknown fractions.
描述了两种定量测量未稀释血浆超滤液中磷酸钙沉淀抑制活性的方法。第一种称为“种子试验”，基于测定从先前已达到恒定[Ca×Pi]过饱和度的超滤液中诱导磷酸钙沉淀所需的磷灰石量。第二种称为“过饱和度试验”，基于测定诱导磷酸钙沉淀所需的最小[Ca×Pi]乘积，同时注意消除螯合剂的影响。使用这两种技术发现焦磷酸盐是最有效的抑制剂，镁和柠檬酸盐的活性较低。在血浆超滤液中的生理浓度下，镁在种子试验中代表了大部分活性，而焦磷酸盐在过饱和度试验中最为重要。然而，这三种已知的抑制剂仅代表了总抑制活性的一部分。在一项初步研究中，肾衰竭患者的已知和未知部分的抑制活性均有所增加。
