Relationship between Components of urinary crystallites and Formation of Calcium Oxalate Stones---An Investigation of 275 Cases of Patients with Calcium Oxalate Stones

[Purpose] This study aimed to investigate the components of urinary crystallites in 275 cases of patients with calcium oxalate (CaOx) stones compared with the components of stones. [Methods] X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectrometer, selected area electron diffraction (SAED) and fast Fourier transformation (FFT) of high-resolution transmission electron microscopy (HRTEM) were performed. [Results] The main components of urinary crystallites in patients with CaOx stones were calcium oxalate monohydrate (COM), uric acid (UA), calcium oxalate dihydrate (COD) and calcium phosphate (CaP), which were similar to the components of stones (COM, COD, UA, and CaP). [Conclusions] The formation of CaOx stone was related to the presence of COM, UA, and CaP crystals in urine. UA and CaP crystals could induce the development of CaOx stones by heterogeneous nucleation. The formation mechanism and the influential factors of CaOx stones were discussed on the basis of the components of crystallites.