Membranes and their constituents as promoters of calcium oxalate crystal formation in human urine
Membranes and their constituents as promoters of calcium oxalate crystal formation in human urine
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DOI：
10.1007/s002230010019
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发表时间：
2000-02-01
影响因子：
4.2
通讯作者：
Hammett-Stabler, C
中科院分区：
文献类型：
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作者：
Khan, SR;Maslamani, SA;Hammett-Stabler, C
我们已经提出细胞降解产物的膜是人体尿液中草酸钙（CaOx）晶体成核的合适底物。人尿对于CaOx一般是亚稳的。为了证明尿液中的细胞膜促进CaOx成核，我们通过过滤或离心去除这些底物，并在过滤或离心前后加入草酸钠诱导结晶。在另一项实验中，将从大鼠肾小管刷边分离的膜泡加入过滤或离心后的尿液中，然后进行结晶诱导。晶体是用粒子计数器来计数的。分析尿液、颗粒和保留物是否存在膜、脂质和蛋白质。进一步将脂质分成不同的类别，进行鉴定和定量。过滤和离心都能去除脂质、蛋白质和膜囊泡，导致尿液中脂质和蛋白质含量的减少。整体形成的晶体比过滤或离心后的尿液中形成的晶体更多。当过滤后的尿液中加入各种尿液成分（如保留酸和磷脂）时，晶体的数量显著增加，这些成分在过滤过程中被去除。我们还确定了CaOx的尿亚稳极限。过滤和离心与亚稳极限的增加有关，而加入膜泡可以降低亚稳极限。这些结果支持了我们的假设，即尿液通常含有CaOx晶体形成的促进子，并且膜及其成分是尿液中晶体成核的最有可能的底物。
We have proposed that membranes of cellular degradation products are a suitable substrate for the nucleation of calcium oxalate (CaOx) crystals in human urine. Human urine is generally metastable with respect to CaOx. To demonstrate that cellular membranes present in the urine promote nucleation of CaOx we removed these substrates by filtration or centrifugation and induced crystallization by adding sodium oxalate, before and after filtration or centrifugation. In a separate experiment, membrane vesicles isolated from rat renal tubular brush border were added into the filtered or centrifuged urine before crystal induction. Crystals were counted using a particle counter. Urine, the pellet, and retentate were analyzed for the presence of membranes, lipids, and proteins. Lipids were further separated into different classes, identified, and quantified. Both filtration and centrifugation removed lipids, proteins, and membrane vesicles, causing a reduction in lipid and protein contents of the urine. More crystals formed in whole than in filtered or centrifuged urine. The number of crystals significantly increased when filtered urine was supplemented with Various urinary components such as the retentate and phospholipids, which are removed during filtration. We also determined the urinary metastable Limit with respect to CaOx. Filtration and centrifugation were associated with increased metastable limit which was reduced by the addition of membrane vesicles. These results support our hypothesis that urine normally contains promoters of CaOx crystal formation and that membranes and their constituents are the most Likely substrate for crystal nucleation in the urine.