Atmani F, Opalko F J, Khan S R
University of Florida, College of Medicine, Department of Pathology and Laboratory Medicine, Gainesville 32610-0275, USA.
Urol Res. 1996;24(1):45-50. doi: 10.1007/BF00296733.
This study was undertaken to identify proteins which are found associated with calcium oxalate crystals induced in vitro in normal human and rat urine. Crystallization was initiated by adding sodium oxalate individually to each urine sample without centrifugation and filtration. Crystals were collected and analyzed by scanning electron microscopy and X-ray diffraction. Crystal matrix proteins (CMPs) were obtained by demineralization of the crystals with ethylenediaminetetra-acetic acid (EDTA) and analyzed by western blotting technique for immunological identification. Crystals produced in human urine were found to be a mixture of calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) while those produced in rat urine were exclusively COD. CMPs extracted from crystals in human urine comprised, in addition to prothrombin-related proteins, osteopontin and albumin. However, CMPs extracted from crystals in rat urine contained only osteopontin and albumin. Prothrombin-related proteins were found only in trace amounts. In a separate experiment, rat urine samples were supplemented with COM before inducing crystallization. Similar results were observed showing that CMP contained osteopontin, albumin and trace amounts of prothrombin-related proteins. We conclude that several urinary macromolecules including not only prothrombin-related proteins, but also osteopontin and albumin, become associated with CaOx crystals. The incorporation of these proteins in growing stones is not only due to the presence of gamma-carboxyglutamic acid as it was suggested for prothrombin-related proteins, but may be due to other factors such as urinary chemistry, presence of glutamic and aspartic acid residues, and calcium-binding sites.
本研究旨在鉴定在正常人尿液和大鼠尿液中体外诱导生成的草酸钙晶体相关蛋白。通过在未离心和过滤的情况下，向每个尿液样本中单独添加草酸钠来启动结晶过程。收集晶体并通过扫描电子显微镜和X射线衍射进行分析。通过用乙二胺四乙酸（EDTA）使晶体脱矿质获得晶体基质蛋白（CMP），并通过蛋白质印迹技术进行免疫鉴定分析。发现人尿液中产生的晶体是一水合草酸钙（COM）和二水合草酸钙（COD）的混合物，而大鼠尿液中产生的晶体仅为COD。从人尿液晶体中提取的CMP除了凝血酶原相关蛋白外，还包括骨桥蛋白和白蛋白。然而，从大鼠尿液晶体中提取的CMP仅含有骨桥蛋白和白蛋白。凝血酶原相关蛋白仅以痕量存在。在另一个实验中，在诱导结晶之前，向大鼠尿液样本中添加COM。观察到类似的结果，表明CMP含有骨桥蛋白、白蛋白和痕量的凝血酶原相关蛋白。我们得出结论，几种尿液大分子不仅包括凝血酶原相关蛋白，还包括骨桥蛋白和白蛋白，与草酸钙晶体相关。这些蛋白质在生长结石中的掺入不仅是由于如凝血酶原相关蛋白所提示的γ-羧基谷氨酸的存在，还可能是由于其他因素，如尿液化学、谷氨酸和天冬氨酸残基的存在以及钙结合位点。
