Document Detail

Methylated purines in urinary stones.
MedLine Citation:
PMID:  15919878     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: The aim of the study was to measure the content of methylated purines that appear as admixtures in uric acid stones. METHODS: We analyzed urinary calculi from 48 residents of Western Pomerania who underwent surgery at the urology ward in Szczecin. Stone samples were dissolved in 0.1 mol/L NaOH. Extracts were diluted in 50 mmol/L KH(2)PO(4) and analyzed by reversed-phase HPLC with ultraviolet detection and use of a gradient of methanol concentration and pH. RESULTS: Uric acid was the main component of 9 stones. All 9 showed admixtures of 9 other purine derivatives: endogenous purine breakdown products (xanthine, hypoxanthine, and 2,8-dihydroxyadenine) and exogenous methyl derivatives of uric acid and xanthine (1-, 3-, and 7-methyluric acid; 1,3-dimethyluric acid; and 3- and 7-methylxanthine). Amounts of these purine derivatives ranged from the limit of detection to 12 mg/g of stone weight and showed a strong positive correlation (Spearman rank correlation coefficients, 0.63-0.94) with the uric acid content of the samples. The main methylated purine in the stones was 1-methyluric acid. CONCLUSIONS: Urinary purines at concentrations below their saturation limits may coprecipitate in samples supersaturated with uric acid and appear as admixtures in urinary stones. The amount of each purine depends on its average urinary excretion, similarity to the chemical structure of uric acid, and concentration of the latter in the stone. These findings suggest that purines in stones represent a substitutional solid solution with uric acid as solvent. Methylxanthines, which are ubiquitous components of the diet, drugs, and uric acid calculi, may be involved in the pathogenesis of urolithiasis.
Krzysztof Safranow; Zygmunt Machoy
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2005-05-26
Journal Detail:
Title:  Clinical chemistry     Volume:  51     ISSN:  0009-9147     ISO Abbreviation:  Clin. Chem.     Publication Date:  2005 Aug 
Date Detail:
Created Date:  2005-07-25     Completed Date:  2005-09-22     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9421549     Medline TA:  Clin Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1493-8     Citation Subset:  IM    
Department of Biochemistry and Chemistry, Pomeranian Medical University, Szczecin, Poland.
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MeSH Terms
Middle Aged
Purines / analysis*
Urinary Calculi / chemistry*
Reg. No./Substance:

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