An understanding of renal stone development in a mixed oxalate-phosphate system.
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.
Guan
Xiangying
X
Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA.
Wang
Lijun
L
Dosen
Anja
A
Tang
Ruikang
R
Giese
Rossman F
RF
Giocondi
Jennifer L
JL
Orme
Christine A
CA
Hoyer
John R
JR
Nancollas
George H
GH
D002130:Calcium Phosphates; D003460:Crystallization; D007669:Kidney Calculi / Q000737:chemistry*; D010070:Oxalates / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D012996:Solutions; D014961:X-Ray Diffraction
D002130:Calcium Phosphates; D010070:Oxalates; D010710:Phosphates; D012996:Solutions; C020243:calcium phosphate