Tiselius Hans-Göran, Ferraz Renato Ribeiro Nogueira, Heilberg Ita Pfeferman
Division of Urology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden.
Urol Res. 2012 Aug;40(4):285-91. doi: 10.1007/s00240-011-0443-1. Epub 2011 Dec 27.
This study aimed at formulating simplified estimates of ion-activity products of calcium oxalate (AP(CaOx)) and calcium phosphate (AP(CaP)) in mouse urineto find the most important determinants in order to limit the analytical work-up. Literature data on mouse urine composition was used to determine the relative effect of each urine variable on the two ion-activity products. AP(CaOx) and AP(CaP) were calculated by iterative approximation with the EQUIL2 computerized program. The most important determinants for AP(CaOx) were calcium, oxalate and citrate and for AP(CaP) calcium, phosphate, citrate, magnesium and pH. Urine concentrations of the variables were used. A simplified estimate of AP(CaOx) (AP(CaOx)-index(MOUSE)) that numerically approximately corresponded to 10(8) × AP(CaOx) was given the following expression:[Formula: see text]For a series of urine samples with various composition the coefficient of correlation between AP(CaOx)-index(MOUSE) and 10(8) × AP(CaOx) was 0.99 (p = 0.00000). A similar estimate of AP(CaP) (AP(CaP)-index(MOUSE)) was formulated so that it approximately would correspond numerically to 10(14) × AP(CaP) taking the following form:[Formula: see text]For a series of variations in urine composition the coefficient of correlation was 0.95 (p = 0.00000). The two approximate estimates shown in this article are simplified expressions of AP(CaOx) and AP(CaP). The intention of these theoretical calculations was not to get methods for accurate information on the saturation levels in urine, but to have mathematical tools useful for rough conclusions on the outcome of different experimental situations in mice. It needs to be emphasized that the accuracy will be negatively influenced if urine variables not included in the formulas differ very much from basic concentrations.
本研究旨在制定小鼠尿液中草酸钙（AP(CaOx)）和磷酸钙（AP(CaP)）离子活性产物的简化估计值，以找出最重要的决定因素，从而限制分析工作。利用关于小鼠尿液成分的文献数据来确定每个尿液变量对这两种离子活性产物的相对影响。AP(CaOx)和AP(CaP)通过使用EQUIL2计算机程序进行迭代近似计算得出。AP(CaOx)的最重要决定因素是钙、草酸盐和柠檬酸盐，而AP(CaP)的最重要决定因素是钙、磷酸盐、柠檬酸盐、镁和pH值。使用的是各变量的尿液浓度。给出了AP(CaOx)的简化估计值（AP(CaOx)-指数（小鼠）），其数值上大致对应于10(8)×AP(CaOx)，表达式如下：[公式：见正文]对于一系列成分各异的尿液样本，AP(CaOx)-指数（小鼠）与10(8)×AP(CaOx)之间的相关系数为0.99（p = 0.00000）。对AP(CaP)进行了类似的估计（AP(CaP)-指数（小鼠）），使其数值上大致对应于10(14)×AP(CaP)，形式如下：[公式：见正文]对于尿液成分的一系列变化，相关系数为0.95（p = 0.00000）。本文所示的这两个近似估计值是AP(CaOx)和AP(CaP)的简化表达式。这些理论计算的目的不是获得关于尿液中饱和度水平的准确信息的方法，而是拥有对小鼠不同实验情况的结果得出粗略结论有用的数学工具。需要强调的是，如果公式中未包含的尿液变量与基本浓度差异很大，准确性将受到负面影响。
