title: Study of stone composition changes in melamine-related urinary calculi and its clinical significance.
abstract: OBJECTIVE
  To investigate the composition changes in melamine-related urinary calculi and their clinical significance.
  
  
  METHODS
  A total of 49 melamine-related urinary calculi were included from 49 children (age 4-82 months, mean 22). The qualitative analysis of stone composition was determined using Fourier transform infrared. The quantitative analysis of the stone computed tomography (CT) attenuation value, stone uric acid level, and stone calcium level were measured using spiral CT, high-performance liquid chromatography, and flame atomic absorption spectrum, respectively.
  
  
  RESULTS
  Fourier transform infrared showed that 41 (84%) of the 49 stones contained uric acid and 25 (51%) contained calcium compounds. The data from the qualitative and quantitative analysis were available for 15 stones because of sample consumption in the detection process (Fourier transform infrared, atomic absorption spectrum, and high-performance liquid chromatography). A negative correlation was observed between stone uric acid level and stone calcium level (n = 15, r = -0.629, P = .009). A positive correlation was observed between the stone calcium level and stone CT attenuation value (n = 25, r = 0.855, P = .000). Compared with the ≤1-year-age group and the 1-2-year-age group, the stone calcium level in the >2-year-age group was significantly greater (27.51% ± 12.65% vs 1.60% ± 1.68% or 10.12% ± 8.69%, P = .000 and P = .003, respectively). Compared with the alkalization-alone group, the stone calcium level in the nonalkalization-alone group was significant greater (19.83% ± 7.48% vs 1.25% ± 1.43%, n = 19, P = .000).
  
  
  CONCLUSIONS
  The stones from children >2 years old were not amenable to medical treatment because they contained greater levels of calcium, which can be demonstrated by the radiologic "positive stone image" or stone CT attenuation value. We believe that surgical invention will be the best choice for such patients if extracorporeal shock wave lithotripsy has failed.
authors.affiliation: Center Laboratory, Department of Urology, People's Hospital in Gansu Province, Lanzhou, China. ly4139@163.com
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.forename: YiRong
authors.initials: Y
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: XiaoGang
authors.initials: X
authors.lastname: Huang
authors.forename: WenHui
authors.initials: W
authors.lastname: Li
authors.forename: XiaoRui
authors.initials: X
authors.lastname: Ru
authors.forename: Min
authors.initials: M
authors.lastname: Meng
authors.forename: Xinsheng
authors.initials: X
authors.lastname: Xi
authors.forename: Gang
authors.initials: G
authors.lastname: Huang
authors.forename: BaoGuang
authors.initials: B
authors.lastname: Shi
authors.forename: Gang
authors.initials: G
authors.lastname: Liu
authors.forename: WeiHua
authors.initials: W
authors.lastname: Li
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D014227:Triazines / Q000506:poisoning*; D014545:Urinary Calculi / Q000139:chemically induced* / Q000737:chemistry*
chemical_list: D014227:Triazines; C011907:melamine