Chemical components of urinary stones according to age and sex of adult patients.

OBJECTIVE: Report the relationship of composition with age and sex of the patients. MATERIAL AND METHOD: A series of 426 urinary stones, 33 from the lower (LUT) and 393 from the upper urinary tract (UUT) of adults, were analyzed for their chemical composition using infrared spectroscopy. The majority of LUT stones were from males (n = 26) and in the age group beyond 60 years (n = 20). RESULTS: Calcium oxalate (CaOx) and uric acid and urate (UA-UR) were the main constituents in LUT stones of males and UA-UR and magnesium ammonium phosphate (MAP) of females. While UA-UR was distributed in all age group of males, it was only detected in elderly females. In cases of UUT stones, the peak finding for both sexes was for the 50-59-year-olds (age class). The MAP component was found more commonly in UUT stones of females, particularly in the younger age groups. CaOx and calcium phosphate (CaP) were the main components of UUT stones in both sexes (CaP was slightly more common in females) with the highest proportion in the 30-49-year-olds (age class), thereafter they declined and were replaced with UA-UR. CONCLUSION: Although the proportion of LUT stones in the present study was small, the present findings agree with previous studies on the role of both age and sex in the etiopathogeny of urinary stones.

Changes in erythrocyte contents of potassium, sodium and magnesium and Na, K-pump activity after the administration of potassium and magnesium salts.

Low potassium and magnesium status and decreased Na, K-pump activity is an endemic condition among rural Northeast Thais. The authors examined the effect of supplementing potassium and magnesium on erythrocyte potassium, sodium and magnesium content and on Na, K-pump activity. Rural Northeast Thai renal stone patients (62) were recruited, divided into four groups and supplemented for one month with potassium chloride (Group1, n = 16), potassium-sodium citrate (Group2, n = 15), chelated magnesium (Group 3, n =16) and potassium-magnesium citrate (Group 4, n =15) in order to achieve 40 mmol potassium, 10 mmol magnesium and 60 mmol citrate daily. After supplementation with potassium (Groups 1, 2 and 4), plasma potassium and Na, K-pump activity rose significantly in Groups 1, 2 and 4, but erythrocyte potassium rose only in Groups 2 and 4. When supplementing elemental magnesium (Groups 3 and 4), the chelated magnesium caused a significant increase in plasma potassium, erythrocyte potassium, sodium and magnesium without a significant increase in Na, K-pump activity. By contrast, potassium-magnesium citrate caused a significant increase in erythrocyte potassium and magnesium and Na, K-pump activity, but depressed erythrocyte sodium. These results suggest the forms of potassium and /or magnesium salts being supplemented should be considered because they affect erythrocyte potassium, sodium and magnesium content and Na, K-pump activity differently.

The effects of potassium and magnesium supplementations on urinary risk factors of renal stone patients.

The effects of potassium and magnesium supplementation on urinary risk factors for renal stone disease were studied in 61 renal stone patients. The subjects were divided into four groups and supplemented for a period of one month with potassium chloride (KCl, Group 1), potassium sodium citrate (K Na citrate, Group 2), magnesium glycine (Mg glycine, Group 3) and potassium magnesium citrate (K Mg citrate, Group 4) with a daily dose of 42 mEq potassium, 21 mEq magnesium or sodium and 63 mEq citrate, accordingly. The results showed that serum potassium and magnesium of all four groups normalized after the supplementation. Though urinary potassium significantly increased in all three groups supplemented with elemental potassium containing solutions [i.e. KCl (p < 0.001), K Na citrate (p < 0.001) and K Mg citrate (p < 0.001)] only K Na citrate and K Mg citrate, caused a significant increase in urinary pH and citrate but decrease in calcium. Supplementation with Mg glycine in Group 3 although caused a significant increase in urinary magnesium, its effects on urinary pH, citrate and calcium, however, were similar to KCl, in that they caused a significant decrease in urinary pH without any change in urinary citrate or calcium. Supplementation with K Mg citrate in Group 4 seems to have given the best results, as far as lowering stone risk factors in that it caused an increase in urinary pH, potassium and citrate and decreased calcium excretions similar to K Na citrate in Group 2. In addition, K Mg citrate also caused the enrichment of urine with magnesium, another inhibitor of calcium-containing stones. Although the four supplements had no effect on urinary saturation of calcium oxalate salt, their effects on the saturations of brushite (CaHPO4 x 2H2O), octacalcium phosphate (Ca8H2 (PO4)6 x 5H2O) and uric acid were clearly associated with changes in urinary pH. Therefore, in Group 1 and 3, subjects having a decrease in urinary pH, also experienced a significant increase in uric acid saturation. Though the saturation of brushite and octacalcium phosphate in Group 2 and 4 and the sodium acid urate in Group 2 were significantly increased, these urinary risk factors could be overcome, however, by the concomitant increase in urinary citrate. The present results demonstrate that for those stone vulnerable subjects having a high risk of potassium and magnesium depletion, to obtain the best therapeutic results, they should be provided supplementations of both potassium and magnesium together and also in the forms that would result in the delivery of an alkali loading effect.