An understanding of renal stone development in a mixed oxalate-phosphate system.

Abstract

The in vivo formation of calcium oxalate concretions having calcium phosphate nidi is simulated in an in vitro (37 degrees C, pH 6.0) dual constant composition (DCC) system undersaturated (sigma DCPD = -0.330) with respect to brushite (DCPD, CaHPO 4 . 2H 2O) and slightly supersaturated (sigma COM = 0.328) with respect to calcium oxalate monohydrate (COM, CaC2O4 . H2O). The brushite dissolution provides calcium ions that raise the COM supersaturation, which is heterogeneously nucleated either on or near the surface of the dissolving calcium phosphate crystals. The COM crystallites may then aggregate, simulating kidney stone formation. Interestingly, two intermediate phases, anhydrous dicalcium phosphate (monetite, CaHPO4) and calcium oxalate trihydrate (COT), are also detected by X-ray diffraction during this brushite-COM transformation. In support of clinical observations, the results of these studies demonstrate the participation of calcium phosphate phases in COM crystallization providing a possible physical chemical mechanism for kidney stone formation.

• Authors: Xiangying Guan, Lijun Wang, Anja Dosen, Ruikang Tang, Rossman F Giese, Jennifer L Giocondi, Christine A Orme, John R Hoyer, George H Nancollas
• Journal: Langmuir : the ACS journal of surfaces and colloids (Langmuir) Vol. 24 Issue 14 Pg. 7058-60 (Jul 15 2008) ISSN: 0743-7463 [Print] United States
• PMID: 18557638 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Calcium Phosphates
• Oxalates
• Phosphates
• Solutions
• calcium phosphate

Topics

• Calcium Phosphates
• Crystallization
• Kidney Calculi (chemistry)
• Oxalates (chemistry)
• Phosphates (chemistry)
• Solutions
• X-Ray Diffraction