Nicar M J, Hill K, Pak C Y
Metabolism. 1983 Sep;32(9):906-10. doi: 10.1016/0026-0495(83)90205-6.
In an effort to develop a simple and reliable method with which to assess the propensity for spontaneous nucleation of calcium oxalate and brushite in urine, the permissible increment of oxalate and calcium was calculated. This represented the additional amount of oxalate or calcium that could be added to urine in three hours before spontaneous precipitation of calcium oxalate or brushite was initiated. The permissible increment of oxalate inversely correlated (P less than 0.001) with the formation-product ratio-activity-product ratio discriminant score of calcium oxalate, which was previously shown to reflect a quantitative measure of the likelihood for spontaneous nucleation. Similarly, the permissible increment of calcium inversely correlated (P less than 0.001) with the formation-product ratio-activity-product ratio discriminant score of brushite. The permissible increments in oxalate and calcium were significantly lower (P less than 0.001) in patients with renal stones than in control subjects. Moreover, treatment with thiazides, allopurinol, sodium cellulose phosphate, orthophosphate, and diphosphonate significantly raised the permissible increment of oxalate in patients with stones. Thus, the permissible increment was reliable in discriminating "stone-forming" from control urine and in assessing response to treatment.
为了开发一种简单可靠的方法来评估尿液中草酸钙和透钙磷石自发成核的倾向，计算了草酸盐和钙的允许增量。这代表了在草酸钙或透钙磷石开始自发沉淀前三小时可添加到尿液中的草酸盐或钙的额外量。草酸盐的允许增量与草酸钙的形成产物比-活性产物比判别分数呈负相关（P小于0.001），先前已表明该分数反映了自发成核可能性的定量测量。同样，钙的允许增量与透钙磷石的形成产物比-活性产物比判别分数呈负相关（P小于0.001）。肾结石患者的草酸盐和钙的允许增量显著低于对照组（P小于0.001）。此外，用噻嗪类、别嘌呤醇、磷酸纤维素钠、正磷酸盐和二膦酸盐治疗可显著提高结石患者草酸盐的允许增量。因此，允许增量在区分“结石形成”尿液和对照尿液以及评估治疗反应方面是可靠的。
