Grases F, Llobera A
Department of Chemistry, University of Balearic Islands, Palma de Mallorca, Spain.
Micron. 1998 Apr-Jun;29(2-3):105-11. doi: 10.1016/s0968-4328(98)00006-7.
An experimental model to reproduce, to some extent, the conditions prevailing during the formation of the so-called sedimentary urinary stones, was developed. The results obtained demonstrated that in the absence of organic matter no calcium phosphate crystals were deposited in cavities with scarce liquid renovation. Nevertheless, in such case a regular hydroxyapatite layer was developed on the walls around the cavity. The presence of crystallization inhibitors cannot stop indefinitely the crystal development. Therefore, phytate manifested important inhibitory effects in concentrations normally found in urine (0.77-1.54 x 10(-6) mol/l), whereas citrate only manifested important inhibitory effects when found at high urinary concentrations (2.64 x 10(-3) mol/l). When mucin (a glycoprotein) was present in the urine, a clear deposit of calcified organic material was formed. The organic matter appeared mixed with the spherulites of hydroxyapatite, this demonstrating the capacity of the glycoprotein agglomerates to act as heterogeneous nucleants of calcium salts and their important role in the formation of sedimentary stones. The structural features of the obtained in vitro deposits were compared with the fine structure of human sedimentary phosphate calculi. Scanning electron microscopy images demonstrated a good correspondence between in vitro experiments and in vivo observations.
建立了一个实验模型，以在一定程度上重现所谓沉积性尿路结石形成过程中存在的条件。所获得的结果表明，在没有有机物的情况下，在液体更新稀少的腔中不会沉积磷酸钙晶体。然而，在这种情况下，在腔周围的壁上会形成规则的羟基磷灰石层。结晶抑制剂的存在不能无限期地阻止晶体的生长。因此，植酸盐在尿液中通常发现的浓度（0.77 - 1.54×10⁻⁶ mol/l）下表现出重要的抑制作用，而柠檬酸盐只有在尿液中高浓度（2.64×10⁻³ mol/l）时才表现出重要的抑制作用。当尿液中存在粘蛋白（一种糖蛋白）时，会形成明显的钙化有机物质沉积物。有机物似乎与羟基磷灰石球粒混合在一起，这表明糖蛋白聚集体作为钙盐的异质成核剂的能力及其在沉积性结石形成中的重要作用。将体外获得的沉积物的结构特征与人类沉积性磷酸盐结石的精细结构进行了比较。扫描电子显微镜图像显示体外实验与体内观察结果有良好的对应关系。
