| Part1of Chapter1Simultaneous determination of oxalate and citrate in urine with ion chromatographyObjective:To establish a new ion-chromatographic method to determine oxalate and citrate simultaneously in urine. And determine normal urine levels of oxalate and citrate in40adults without kidney stone.Methods:Separation and quantitation of oxalate and citrate from other urinary consituents was performed using a ICS-90Ion Chromatography System (Dionex Corporation, Sunnyvale,California, USA). chromatographic column Lon Pac AS23(4×250mm) and guard column Lon Pac AG23(4X50mm) were also used in the study.35MMNaOH was used as eluant. The eluant flow rate was lml/min. ulfuric acid was used as regenerant set. Urine sample was diluted50-fold in deionized water and injected into anion exchange analytical column. Forty normal subjects were active healthy individuals with no history of either renal disease or renal stone disease, the levels of oxalte and citrate in urine were determined.Results:The appearance time of oxalate and citrate were about6min and llmin respectively. A linear regression analysis calibration curve for oxalate and citrate concentration as a function of peak area gave an r2value of0.999. The detection limit for urine oxalate and citrate were0.05mg/L and0.25mg/L respectively. The interassay and between-assay coefficients of variation were all below10%. The average level of oxalate and citrate in healthy individuals’24h urine were33.94±8.29mg/d and297.55±86.59mg/d respectively.Conclusion:The method was simple, accurate and rapid, and can be used to determine urinary oxalate and citrate in clinical practice. The levels of citrate in heathy individuals showed that the normal level of urine citrate perhaps lower than people in European countries. Part2of Chaper1Metabolic evaluation in high-risk calcium oxalate stone formerObjective:In this study, we we aimed to determine the metabolic risk factors in high-risk calcium oxalate stone former through metabolic evaluation.Methods:Between March and October2010, sixty six patients with high risk of calcium oxalate stone formation underwent metabolic evaluation in our department. The evaluation included blood chemistry studies and24-hour urine analyses. The levels of calcium, uric acid, oxalate, citrate, phosphonium, potassium and sodium were measured in the24-hour urine collection.Results:The mean age of patients was37.8yeas,51of them were male and15were female. The mean levels of urine calcium, oxalate, citrate and uric acid were305.50±153.52mg/d,50.00±18.94mg/d,240.83±177.94mg/d and403.81±130.27mg/d respectively. Metabolic risk factors were demonstrated in65patients (98.5%). Hypocitraturia(75.8%), hypercalciuria(72.7%) and hyperoxaluria(54.5%) were the most common metabolic risk factors in the patients. And many patients had more than one risk factor,10patients (15.2%) had one risk factor,38patients (57.6%) had2risk factors,15patients (22.7%) had3risk factors, and2patients (3.0%) had4risk factors.Conclusion:Hypocitraturia, hypercalciuria and hyperoxaluria were were the most common metabolic risk factors in the patients with high risk of calcium oxalate stone formation. And multiple risk factors could be found in one patient. The rate of Hypocitraturia, hypercalciuria was much higher than that in European countries. Chapter2The verification for the hypothesis of "calcium intake-dependence hyperoxaluria"Objective:To verify the hypothesis of calcium intake-dependence hyperoxaluria though comparing oxalate levels in different calcium intake levels.Methods:Between March and September2010, fifty five patients with calcium oxalate stone in our hospital joined this study. The first time we detect calcium and oxalate level in urine when patients under normal diet and second time we asked patients to collect24-h urine after1week of dietary with restrictions of calcium load. And then give supplemental calcium (calcium gluconate,500mg/pellet, containing calcium element45mg per pellet) to patients.24-h urine should be collected after3day of dietary with supplemental180mg calcium element.Result:The urine calcium in normal diet, calcium restricted diet, and diet with supplement calcium were317.42±157.04mg/d,277.94±127.78mg/d and337.75±153.82mg/d respectively, the corresponding oxalate level were49.81±19.97mg/d,48.03±22.98mg/d and50.16±30.85mg/d respectively. The urine calcium increase significantly with the increase of calcium intake. However, no significant difference was found in urine oxalate level between three groups.Conclusion:The level of urine oxalate did not decrease with the increase of calcium intake by medical supplement. The result did not support the hypothesis of "calcium intake-dependence hyperoxaluria" Chapter3Determination of glycolate in urine with ion-chromatographyObjective:To establish a method to determine glycolate in urine by ion-chromatographic.Methods:Separation and quantisation of oxalate and citrate from other urinary consituents was performed using a ICS-90Ion Chromatography System (Dionex Corporation, Sunnyvale,California, USA). Chromatographic column Lon Pac AS23(4×250mm) and guard column Lon Pac AG23(4x50mm) were used in the study.10MM sodium tetraborate was used as eluant. The eluant flow rate was1ml/min. ulfuric acid was used as regenerant set. Urine sample was diluted10-fold in deionized water and injected into anion exchange analytical column.Results:The appearance time of glycolate was about lOmin. A linear regression analysis calibration curve for glycolate concentration as a function of peak area gave an r2value of0.999. The detection limit for glycolate was0.8mg/L respectively. The interassay and between-assay coefficients of variation were all below10%.Conclusion:The method was simple, accurate and rapid, and can be used to determine urinary glycolate in clinical practice. |
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