Guerra Angela, Meschi Tiziana, Allegri Franca, Prati Beatrice, Nouvenne Antonio, Fiaccadori Enrico, Borghi Loris
Department of Clinical Sciences, University of Parma, Parma, Italy.
Urol Res. 2006 Dec;34(6):359-64. doi: 10.1007/s00240-006-0067-z.
Supplementation of certain calcium crystallization inhibitors, such as citrate and magnesium, and the dilution of urine with water are now considered consolidated practice for the prevention of calcium kidney stones. The aim of this study is to verify, using tried and true in vitro methods, whether the effect of these inhibitors can manifest itself in different ways depending on whether the urine is concentrated or diluted. Calcium oxalate crystallization was studied on 4-h urine of 20 male idiopathic calcium oxalate stone formers, first under low hydration conditions (non-diluted urine) and then under high hydration conditions (diluted urine). Both the diluted and the non-diluted urine samples were subjected to three types of load: (a) an oxalate concentration increment of 1.3 mmol/l only; (b) an oxalate concentration increment of 1.3 mmol/l with a citrate concentration increment of 1.56 mmol/l; (c) an oxalate concentration increment of 1.3 mmol/l with a magnesium concentration increment of 2.08 mmol/l. In non-diluted urine, the addition of the citrate and magnesium did not modify the crystallization parameters under study. In contrast, in the diluted urine the addition of the citrate and magnesium led to a reduction in the total quantity of crystals (equivalent to 35-45%) and their aggregates (equivalent to 30-40%); at the same time, there was an increase in the diameter of the monohydrate calcium oxalate crystals, which also underwent a morphological change. In conclusion, the inhibitory effects of citrate and magnesium on the crystallization of calcium oxalate do not manifest themselves in highly concentrated urine.
补充某些钙结晶抑制剂，如柠檬酸盐和镁，并用水稀释尿液，现在被认为是预防钙肾结石的常规做法。本研究的目的是使用经过验证的体外方法，验证这些抑制剂的效果是否会因尿液浓缩或稀释而以不同方式表现出来。对20名特发性草酸钙结石男性患者的4小时尿液进行草酸钙结晶研究，首先在低水合条件下（未稀释尿液），然后在高水合条件下（稀释尿液）。稀释和未稀释的尿液样本都接受了三种类型的负荷：（a）仅草酸盐浓度增加1.3 mmol/l；（b）草酸盐浓度增加1.3 mmol/l，柠檬酸盐浓度增加1.56 mmol/l；（c）草酸盐浓度增加1.3 mmol/l，镁浓度增加2.08 mmol/l。在未稀释的尿液中，添加柠檬酸盐和镁并未改变所研究的结晶参数。相比之下，在稀释尿液中添加柠檬酸盐和镁导致晶体总量（相当于35-45%）及其聚集体（相当于30-40%）减少；同时，一水合草酸钙晶体的直径增加，其形态也发生了变化。总之，柠檬酸盐和镁对草酸钙结晶的抑制作用在高度浓缩的尿液中并未表现出来。
