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Calcium Oxalate Stones (calcium + oxalate_stone)
Selected AbstractsUrolithiasis in Okinawa, Japan: A relatively high prevalence of uric acid stonesINTERNATIONAL JOURNAL OF UROLOGY, Issue 8 2003RAYHAN ZUBAIR HOSSAIN Abstract Aim:, The aim of the present study was to investigate the composition of urinary tract stones in patients from Okinawa, the most southern island group of Japan. Methods:, The study was conducted by 12 hospitals in Okinawa. A total of 1816 urinary tract calculi were obtained from 1816 patients (1323 males; 493 females). The patients had a mean age of 53 ± 15.3 years (mean ± SD). The calculi were examined to determine their chemical composition. Stone samples were analyzed by computed infrared spectrophotometer. Results:, Pure stones comprised 58.4% of the total, with calcium oxalate stones accounting for 40% (21% monohydrate [whewellite]; 6.6% dihydrate [weddellite]; and 12.4% combined monohydrate and dihydrate stones), uric acid/urate stones for 9.6%, calcium phosphate stones for 5.1%, and struvite stones for 3.7%. The other 41.6% of the stones consisted of calcium oxalate mixed with other components. The male-to-female ratio was 2.7 : 1. Conclusion:, In our series, calcium oxalate stones accounted for 81.6% of the urinary tract calculi, while uric acid/urate stones accounted for 15.8%. Uric acid stones, predominantly the anhydrous and/or dihydrate forms, showed a relatively high prevalence. Calcium oxalate stones, predominantly in the form of whewellite, showed a high prevalence among pure calculi; while the predominant combinations among mixed calculi were weddellite + calcium phosphate and whewellite + uric acid/urate. [source] Mechanism of calcium oxalate renal stone formation and renal tubular cell injuryINTERNATIONAL JOURNAL OF UROLOGY, Issue 2 2008Masao Tsujihata Abstract: Formation of calcium oxalate stones tends to increase with age and begins from the attachment of a crystal formed in the cavity of renal tubules to the surface of renal tubular epithelial cells. Though most of the crystals formed in the cavity of renal tubules are discharged as is in the urine, in healthy people, crystals that attach to the surface of renal tubular epithelial cells are thought to be digested by macrophages and/or lysosomes inside of cells. However, in individuals with hyperoxaluria or crystal urine, renal tubular cells are injured and crystals easily become attached to them. Various factors are thought to be involved in renal tubular cell injury. Crystals attached to the surface of renal tubular cells are taken into the cells (crystal,cell interaction). And then the crystal and crystal aggregates grow, and finally a stone is formed. [source] Urolithiasis in Okinawa, Japan: A relatively high prevalence of uric acid stonesINTERNATIONAL JOURNAL OF UROLOGY, Issue 8 2003RAYHAN ZUBAIR HOSSAIN Abstract Aim:, The aim of the present study was to investigate the composition of urinary tract stones in patients from Okinawa, the most southern island group of Japan. Methods:, The study was conducted by 12 hospitals in Okinawa. A total of 1816 urinary tract calculi were obtained from 1816 patients (1323 males; 493 females). The patients had a mean age of 53 ± 15.3 years (mean ± SD). The calculi were examined to determine their chemical composition. Stone samples were analyzed by computed infrared spectrophotometer. Results:, Pure stones comprised 58.4% of the total, with calcium oxalate stones accounting for 40% (21% monohydrate [whewellite]; 6.6% dihydrate [weddellite]; and 12.4% combined monohydrate and dihydrate stones), uric acid/urate stones for 9.6%, calcium phosphate stones for 5.1%, and struvite stones for 3.7%. The other 41.6% of the stones consisted of calcium oxalate mixed with other components. The male-to-female ratio was 2.7 : 1. Conclusion:, In our series, calcium oxalate stones accounted for 81.6% of the urinary tract calculi, while uric acid/urate stones accounted for 15.8%. Uric acid stones, predominantly the anhydrous and/or dihydrate forms, showed a relatively high prevalence. Calcium oxalate stones, predominantly in the form of whewellite, showed a high prevalence among pure calculi; while the predominant combinations among mixed calculi were weddellite + calcium phosphate and whewellite + uric acid/urate. [source] A critical analysis of the role of gut Oxalobacter formigenes in oxalate stone diseaseBJU INTERNATIONAL, Issue 1 2009Siddharth Siva Hyperoxaluria is a major risk factor for the formation of calcium oxalate stones, but dietary restriction of oxalate intake might not be a reliable approach to prevent recurrence of stones. Hence, other approaches to reduce urinary oxalate to manage stone disease have been explored. The gut-dwelling obligate anaerobe Oxalobacter formigenes (OF) has attracted attention for its oxalate-degrading property. In this review we critically evaluate published studies and identify major gaps in knowledge. Recurrent stone-formers are significantly less likely to be colonized with OF than controls, but this appears to be due to antibiotic use. Studies in animals and human subjects show that colonization of the gut with OF can decrease urinary oxalate levels. However, it remains to be determined whether colonization with OF can affect stone disease. Reliable methods are needed to detect and quantify colonization status and to achieve durable colonization. New information about oxalate transport mechanisms raises hope for pharmacological manipulation to decrease urinary oxalate levels. In addition, probiotic use of lactic acid bacteria that metabolize oxalate might provide a valid alternative to OF. [source] Enlargement of calcium oxalate stones to clinically significant size in an in-vitro stone generatorBJU INTERNATIONAL, Issue 9 2002K. Ananth Objective ,To develop and validate an in vitro method suitable for the quantitative investigation of the growth of calcium oxalate stones through to a clinically significant size. Materials and methods ,Small fragments of calcium oxalate calculi were suspended in a mixed suspension/mixed product removal crystalliser supplied with artificial urine supersaturated with calcium oxalate. The fragments were weighed at regular intervals until they reached ,,500 mg. The results were plotted as weight against time and fitted to equations corresponding to constant increase in diameter, surface area-controlled and constant-deposition growth patterns. The choice of the most appropriate model was based on the squared regression coefficient (r2). Results ,Eight fragments (2,6 mm in diameter) were grown to ,,10 mm in diameter over periods from 137 to 369 h. Seven of the growth curves were best-fitted (r2 , 0.988) by the equation w = kt(3/2) + c, where w is the weight, k is a growth constant, t is the time and c is a constant approximating to the initial weight. This corresponds to a surface area-dependent mechanism. Conclusions ,The growth of these small fragments to a clinically significant size accelerated throughout the experimental period in a way which was consistent with a surface area-dependent mechanism. We have developed a resilient model suitable for studying the kinetics of calcium oxalate stone growth in vitro. [source] | ||||||||||