***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: In a double-blind prospect i ve clinical study patients with at least two verified episodes of urolithiasis , but stone-free at the time of inclusion in the study , were subjected to prophylactic treatment with either bendroflumethiazide ( 2.5 mg)+573 mg potassium chloride 3 times a day , or placebo . The material included a total of 22 patients , all males , aged 20–49 years . We found a clear tendency to reduced stone formation in the group treated with the active drug ( P<0.1 ) . Calcium excretion was reduced by 25–50 % in 7 of 12 patients treated with thiazide In an attempt to document the efficacy of potassium citrate in stone formation , 57 patients with active lithiasis ( 2 or more stones during the preceding 2 years ) and hypocitraturia were r and omly allocated into 2 groups , with 1 group taking 30 to 60 mEq . potassium citrate daily in wax matrix tablet formation and the other group receiving placebo . In 18 patients receiving  potassium citrate for 3 years stone formation significantly declined after treatment from 1.2 + /- 0.6 to 0.1 + /- 0.2 per patient year ( p < 0.0001 ) , in 13 patients ( 72 % ) the disease was in remission and all patients showed a reduced stone formation rate individually . In contrast , 20 patients taking placebo medication for 3 years showed no significant change in stone formation rate ( 1.1 + /- 0.4 to 1.1 + /- 0.3 per patient year ) and in only 4 patients ( 20 % ) was the disease in remission . The stone formation rate during potassium citrate treatment was significantly lower than during the placebo treatment ( 0.1 + /- 0.2 versus 1.1 + /- 0.3 per patient year , p < 0.001 ) . Potassium citrate therapy caused a significant increase in urinary citrate , pH and potassium , whereas placebo did not . Adverse reactions to potassium citrate were mild causing only 2 patients in the potassium citrate group and 1 in the placebo group to withdraw from the study . In summary , our r and omized trial showed the efficacy of potassium citrate in preventing new stone formation in idiopathic hypocitraturic calcium nephrolithiasis PURPOSE Exposure to the microgravity environment of space increases the risk of kidney stone formation , particularly for calcium oxalate and uric acid stones . This study was performed to evaluate the efficacy of potassium alkali as potassium-magnesium citrate in reducing renal stone risk and bone turnover . MATERIAL S AND METHODS This study was performed as a double-blind , placebo controlled trial . We studied 20 normocalciuric subjects r and omized to either placebo or potassium-magnesium citrate ( 42 mEq potassium , 21 mEq magnesium , 63 mEq citrate per day ) before and during 5 weeks of strict bed rest . The study was performed in the General Clinical Research Center and under a controlled dietary regimen composed of 100 mEq of sodium , 800 mg of calcium , 0.8 gm/kg animal protein and 2,200 kcal per day . Two 24-hour urine collection s were obtained under oil each week for assessment of stone risk parameters and relative saturation of calcium oxalate , brushite and undissociated uric acid . Blood was also collected for determination of serum immunoreactive parathyroid hormone and vitamin D metabolites . RESULTS Bed rest promoted a rapid increase in urinary calcium excretion of approximately 50 mg per day in both groups . Despite this increase subjects treated with potassium-magnesium citrate demonstrated significant decreases in the relative saturation of calcium oxalate and in the concentration of undissociated uric acid compared to placebo .  Immunoreactive parathyroid hormone , serum 1,25-dihydroxyvitamin D and intestinal calcium absorption all decreased in both groups with no difference in response between the 2 treatment arms . CONCLUSIONS Provision of alkali as potassium-magnesium citrate is an effective countermeasure for the increased risk of renal stone disease associated with immobilization . Despite an increase in urine calcium concentration , the relative saturation of calcium oxalate decreased due to citrate chelation of calcium and the concentration of undissociated uric acid decreased due to the significant increase in urine Aim : To compare efficacy and tolerability of phytotherapy ( PT ) vs. potassium citrate ( KC ) in patients with minimal nephrolithiasis . To compare and assess changes in value of certain serum ( Ca2 + , PO43- , uric acid [ UA ] ) and urinary ( 24-hr Ca2 + , PO43- , UA , citrate , oxalate , and urine pH ) parameters in patients being treated with PT or KC .  Material s and Methods : After clearance by the local institutional ethics committee , 60 patients of nephrolithiasis who had consented for the study , were enrolled ( as per entry criteria ) and r and omized into citrate therapy ( group-I ) or PT ( group-II ) . PT was administered as a nutritional supplement , using a lupeol-based extract ( Tablet Calcury ™ , two tablets twice a day ) . They were monitored for the changes in the serum and urinary biochemical , radiological , and clinical parameters ( efficacy and tolerability ) as per protocol . Results : Group-I patients demonstrated favorable changes in certain biochemical parameters ( decreased serum calcium , urinary UA/oxalate , increased urinary citrate and pH ) along with significant symptomatic improvement ( decrease in visual analogue pain score with increased stone clearance/reduction in stone size ) . Four ( 13.3 % ) patients of group-I had mild upper gastrointestinal discomfort which was controlled with antacids . Group-II patients had favorable changes in biochemical parameters ( decreased serum UA and increased urinary citrate ) along with significant symptomatic improvement ( reduction/clearance in the stone size ) , but without any noticeable side effects . Conclusions : Medical therapies with both KC and PT ( with lupeol extract using Calcury ™ ) were effective in reducing the stone size and symptoms of nephrolithiasis . It appeared that KC was biochemically efficacious in producing some favorable biochemical changes with some side effects , whereas PT was probably clinical ly efficacious in hastening stone expulsion ( < 8 mm ) without any observed adverse events . Although both the medical therapies were not effective in all aspects , we believe that PT using lupeol-based extract ( Calcury ™ ) may be used as an alternative form of medical therapy in select patients with minimal nephrolithiasis . Long-term r and omized placebo-controlled trials are needed to better define the precise role of lupeol-based PT vs. citrate therapy in minimal nephrolithiasis In 14 women aged 37 - 68 y with a history of renal calcium calculi , bone densities were 12.0 % below those of age-matched control subjects at the L2 - 4 lumbar spine ( P = 0.007 ) and 6.4 % less at the femoral neck ( P = 0.095 ) . A low-oxalate diet was supplemented with 1 g Ca/d as citrate . In 6 mo , plasma 1,25(OH)2D concentrations fell from 53.2 + /- 18.8 to 41.9 + /- 15.2 ng/L ( P = 0.02 ) and parathyroid hormone from 39.1 + /- 17.0 to 30.8 + /- 12.5 ng/L ( P = 0.02 ) . Calcium oxalate saturation was 2.15 + /- 1.38 at baseline , 2.27 + /- 1.00 at 1 mo , and 2.06 + /- 1.57 at 6 mo . The increase in urinary calcium at 1 mo from 4.411 + /- 1.87 to 6.514 + /- 2.82 mmol/24 h ( P = 0.01 ) was offset by a parallel increase in citrate excretion from 2.909 + /- 1.45 to 3.455 + /- 1.34 mmol/24 h ( P = 0.03 ) . Calcium citrate supplementation did not increase the lithogenicity of the women in this protocol Alkali therapy is used commonly to prevent recurrent stone formation in patients with distal renal tubular acidosis . We compared the effects of potassium citrate to those of sodium citrate in 6 well defined cases of incomplete distal renal tubular acidosis . The patients were studied during a control phase , during potassium citrate treatment ( 80 mEq . per day ) and during sodium citrate treatment ( 80 mEq . per day ) chosen in r and om order . Potassium citrate caused a decrease in urinary calcium and a significant increase in urinary citrate that result ed in a significant decrease in the urinary saturation of calcium oxalate . It did not alter the saturation of brushite and sodium urate . However , while sodium citrate also was able to increase the urinary citrate level , there was no decrease in the urinary calcium ( owing to the increased sodium load ) . Thus , the urinary saturation of calcium oxalate did not decrease as much as with potassium citrate and the saturation of brushite increased significantly . Moreover , the urinary saturation of sodium urate increased significantly owing to the enhanced sodium excretion . The results suggest that potassium citrate therapy may retard the crystallization of calcium oxalate and may not cause calcium phosphate crystallization . In contrast , sodium citrate may have no effect or it sometimes may accentuate the crystallization of calcium salts . Thus , our study supports the potential clinical advantage of potassium citrate therapy over sodium alkali treatment in patients with incomplete distal renal tubular acidosis and recurrent calcium nephrolithiasis OBJECTIVE To determine urinary citrate excretion in children with nephrolithiasis and normal controls . DESIGN Prospect i ve . SETTING Tertiary care center in New Delhi . METHODS This study was done on 50 children , below the age of 12 years , with idiopathic urinary calculi and 150 age and weight matched controls . The children were divided into 3 groups : Group 1 ( 1 - 4 years ) , Group 2 ( 5 - 8 years ) and Group 3 ( 9 - 12 years ) . Urinary citrate was estimated in a 24-hour urine sample using colorimetric method . The stones removed from these children were also analysed . RESULTS There was a preponderance of urinary stones in males ; the highest incidence being in Group 1 . Excretion of citrate in 24-hour urine sample was significantly lower in patients compared to controls , for males in all age groups and for females in Group 3 . However , there was no statistically significant difference in the urinary citrate value between males and females in a given age group for either controls or patients . The urinary citrate excretion increased with age in patients and controls , but the levels in patients were lower . Depending upon the constituents , four types of stones were identified , calcium phosphate , calcium oxalate , uric acid and magnesium ammonium phosphate . Nine stones had at least more than one major constituent . Hypocitraturia was detected in 43 percent cases . The incidence was 76 percent for calcium phosphate , 87 percent for calcium oxalate , 40 percent for uric acid stones and 50 percent for magnesium ammonium phosphate . CONCLUSION This study shows that low urinary citrate is associated with urinary stones in children , especially in endemic areas , in the absence of obvious etiological factors . Urinary citrate excretion should be determined in all children with nephrolithiasis PURPOSE We evaluated the effect of calcium citrate supplementation alone or in combination with potassium citrate on the stone forming propensity in healthy postmenopausal women . MATERIAL S AND METHODS A total of 18 postmenopausal women without stones underwent a r and omized trial of 4 phases comprised of 2 weeks of treatment with placebo , calcium citrate ( 400 mg calcium twice daily ) , potassium citrate ( 20 mEq twice daily ) , and calcium citrate and potassium citrate ( at same doses ) . During the last 2 days of each phase urine was collected in 24-hour pools for complete stone risk analysis . RESULTS Compared to placebo , calcium citrate increased urinary calcium and citrate but decreased urinary oxalate and phosphate . Urinary saturation of calcium oxalate , brushite and undissociated uric acid did not change . Potassium citrate decreased urinary calcium , and increased urinary citrate and pH. It decreased urinary saturation of calcium oxalate and undissociated uric acid , and did not change the saturation of brushite . When calcium citrate was combined with potassium citrate , urinary calcium remained high , urinary citrate increased even further and urinary oxalate remained reduced from the calcium citrate alone , thereby marginally decreasing the urinary saturation of calcium oxalate . Urinary pH increased , decreasing urinary undissociated uric acid . The increase in pH increased the saturation of brushite despite the decrease in urinary phosphorus . CONCLUSIONS Calcium citrate supplementation does not increase the risk of stone formation in healthy postmenopausal women . The co-administered potassium citrate may provide additional protection against formation of uric acid and calcium oxalate stones Purpose To study the effects of long-term treatment 
    Output:
    
Citrate salts prevent new stone formation and reduce further stone growth in patients with residual stones that predominantly contain oxalate .