Tiselius H G
Department of Urology, University Hospital, Linköping, Sweden.
Urol Int. 1991;47(4):255-9. doi: 10.1159/000282232.
A previously formulated simplified estimate of the ion activity product of calcium oxalate, AP(CaOx) index, was modified in order to better correspond numerically to the ion activity product obtained by computed iterative approximation with the EQUIL 2 program. The new index, AP(CaOx) index EQ, was given the following form for a 4-hour urine: 1.9 x Ca(0.84) x Ox x Mg-(0.12) x Cit-(0.22) x V-(1.03), where the excretion of calcium, oxalate (Ox), magnesium and citrate (Cit) was expressed in millimoles excreted during the period, and urine volume (V) in liters. There was a good correlation between AP(CaOx) index and AP(CaOx) index EQ (r = 0.98). A standardized index calculated for a 24-hour urine volume of 1.5 liters, AP(CaOx) index EQ(s), was significantly higher in stoneforming men (p less than 0.001) and women (p less than 0.001) than in normal subjects. The mean ion activity products of CaOx at the start of crystallization in salt solutions and dialyzed urine were 2.74 +/- 0.25 x 10(-8) and 3.50 +/- 0.33 x 10(-8) (mol/l)2, respectively. In the urine from normal subjects, AP(CaOx) index EQ at the point of crystallization was 4.3 +/- 1.1 and in the urine from stone formers 2.8 +/- 0.5 (p less than 0.001). From calculation of AP(CaOx) index EQ in hourly collected urine, it was assumed that the risk of exceeding the level where crystallization starts during periods with the highest supersaturation can be anticipated when the 24-hour AP(CaOx) index EQ value exceeds 2.0.
为了在数值上更好地与通过EQUIL 2程序计算迭代近似得到的离子活度积相对应，对先前制定的草酸钙离子活度积的简化估计值——AP（CaOx）指数进行了修正。新指数AP（CaOx）指数EQ对于4小时尿液具有以下形式：1.9×Ca(0.84)×Ox×Mg-(0.12)×Cit-(0.22)×V-(1.03)，其中钙、草酸盐（Ox）、镁和柠檬酸盐（Cit）的排泄量以该时间段内排泄的毫摩尔数表示，尿量（V）以升表示。AP（CaOx）指数与AP（CaOx）指数EQ之间存在良好的相关性（r = 0.98）。针对24小时尿量为1.5升计算的标准化指数AP（CaOx）指数EQ(s)，在结石形成男性（p < 0.001）和女性（p < 0.001）中显著高于正常受试者。盐溶液和透析尿液中结晶开始时CaOx的平均离子活度积分别为2.74±0.25×10(-8)和3.50±0.33×10(-8)（mol/l）2。在正常受试者的尿液中，结晶点处的AP（CaOx）指数EQ为4.3±1.1，在结石形成者的尿液中为2.8±0.5（p < 0.001）。通过计算每小时收集尿液中的AP（CaOx）指数EQ，假定当24小时AP（CaOx）指数EQ值超过2.0时，可以预期在过饱和度最高的时期超过结晶开始水平的风险。
