Ananth K, Kavanagh J P, Walton R C, Rao P N
Lithotriptor Unit, South Manchester University Hospital Trust, Wythenshawe Hospital, Manchester, UK.
BJU Int. 2002 Dec;90(9):939-44. doi: 10.1046/j.1464-410x.2002.03027.x.
To develop and validate an in vitro method suitable for the quantitative investigation of the growth of calcium oxalate stones through to a clinically significant size.
Small fragments of calcium oxalate calculi were suspended in a mixed suspension/mixed product removal crystalliser supplied with artificial urine supersaturated with calcium oxalate. The fragments were weighed at regular intervals until they reached approximately equal 500 mg. The results were plotted as weight against time and fitted to equations corresponding to constant increase in diameter, surface area-controlled and constant-deposition growth patterns. The choice of the most appropriate model was based on the squared regression coefficient (r2).
Eight fragments (2-6 mm in diameter) were grown to approximately 10 mm in diameter over periods from 137 to 369 h. Seven of the growth curves were best-fitted (r2 > or = 0.988) by the equation w = kt(3/2) + c, where w is the weight, k is a growth constant, t is the time and c is a constant approximating to the initial weight. This corresponds to a surface area-dependent mechanism.
The growth of these small fragments to a clinically significant size accelerated throughout the experimental period in a way which was consistent with a surface area-dependent mechanism. We have developed a resilient model suitable for studying the kinetics of calcium oxalate stone growth in vitro.
开发并验证一种体外方法，该方法适用于对草酸钙结石生长至具有临床意义大小的过程进行定量研究。
将草酸钙结石的小碎片悬浮于配备有草酸钙过饱和人工尿液的混合悬浮液/混合产物移除结晶器中。定期对碎片称重，直至其重量达到约500毫克左右。将结果绘制成重量对时间的曲线，并拟合对应于直径持续增加、表面积控制和恒定沉积生长模式的方程。基于平方回归系数（r²）来选择最合适的模型。
八个碎片（直径2 - 6毫米）在137至369小时的时间段内生长至直径约10毫米。七条生长曲线最适合（r²≥0.988）的方程为w = kt^(3/2) + c，其中w为重量，k为生长常数，t为时间，c为近似初始重量的常数。这对应于一种依赖表面积的机制。
在整个实验期间，这些小碎片生长至具有临床意义大小的过程加速，其方式与依赖表面积的机制一致。我们开发了一种适用于研究体外草酸钙结石生长动力学的可靠模型。
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