Is citrate an inhibitor of calcium oxalate crystal growth in high concentrations of urine?
Is citrate an inhibitor of calcium oxalate crystal growth in high concentrations of urine?
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DOI：
10.1007/bf00431081
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发表时间：
2004
影响因子：
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通讯作者：
H. Bek-Jensen;A. Fornander;M. Nilsson;H. Tiselius
中科院分区：
文献类型：
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作者：
H. Bek-Jensen;A. Fornander;M. Nilsson;H. Tiselius
研究了柠檬酸盐对草酸钙（CaOx）晶体生长的影响，在该系统中，一系列含有[45 Ca]氯化钙的样品被不同浓度的草酸盐带到不同水平的过饱和度。通过在将CaOx晶种添加到含有柠檬酸盐的样品中（浓度对应于最终尿液中的浓度）后30分钟测量溶液中剩余的同位素量来评估结晶。实验在纯盐溶液和透析尿液溶液中进行。在存在和不存在透析尿液的情况下，柠檬酸盐浓度增加导致CaOx结晶减少，但含尿液的样品中结晶速率最低。溶液中剩余的45 Ca浓度增加反映了结晶减少，这可能是由于过饱和度降低和CaOx晶体生长抑制增加。柠檬酸盐对CaOx晶体生长的直接影响通过计算相应结晶度下CaOx的离子活度积（APCaOx）来评估。在有和无透析尿液的样本中，溶液中同位素量减少30%时记录的APCaOx随柠檬酸盐浓度（1.0 - 1.5 mmol/l）的增加而增加。这些发现表明柠檬酸盐对CaOx晶体生长具有弱的直接抑制作用，这增加了由尿大分子和降低的过饱和度引起的生长速率降低。
The effect of citrate on calcium oxalate (CaOx) crystal growth was studied in a system in which series of samples containing [45Ca]calcium chloride were brought to different levels of supersaturation with various concentrations of oxalate. The crystallization was assessed by measuring the amount of isotope remaining in solution 30 min after the addition of CaOx seed crystals to samples containing citrate in concentrations corresponding to those in final urine. The experiments were carried out both in pure salt solutions and in solutions with dialysed urine. Increased concentrations of citrate resulted in a reduced crystallization of CaOx in both the presence and absence of dialysed urine, but with the lowest rate of crystallization in the samples containing urine. The increased concentration of45Ca remaining in solution reflected a reduced crystallization, which could possibly be explained both by a reduced supersaturation and by an increased inhibition of CaOx crystal growth. The direct effects of citrate on CaOx crystal growth were assessed by calculating the ion-activity product of CaOx (APCaOx) at corresponding degrees of crystallization. The APCaOxrecorded at a 30% reduction of the amount of isotope in solution increased with increasing concentrations of citrate between 1.0 and 1.5 mmol/l in samples both with and without dialysed urine. These findings indicate that citrate has a weak direct inhibitory effect on CaOx crystal growth, which adds to the reduced growth rate brought about by urinary macromolecules and a decreased supersaturation.