Equil2: A Basic Computer Program for the Calculation of Urinary Saturation

Werness, P. G.; Brown, C. M.; Smith, Lynwood H.; Finlayson, Birdwell

doi:10.1016/s0022-5347(17)47703-2

Cited by 479 publications

(205 citation statements)

References 13 publications

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“…Twentyfour-hour urinary concentrations of oxalate, calcium and other determinants of supersaturation were measured in the Mayo Clinic Renal Testing Laboratory. Supersaturation was calculated using the EQUIL2 program (8).…”

Section: Urine Collectionmentioning

confidence: 99%

Heritability of Urinary Traits That Contribute to Nephrolithiasis

Lieske

Turner

Edeh

et al. 2014

Clinical Journal of the American Society of Nephrology

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Background and objectives Kidney stones and their risk factors aggregate in families, yet few studies have systematically estimated heritabilities and genetic correlations of the numerous urinary traits associated with risk of kidney stones.Design, setting, participants, & measurements Twenty-four-hour urine samples were collected from the Genetic Epidemiology Network of Arteriopathy cohort of families in Rochester, Minnesota, to measure urinary determinants of supersaturation. Diet was assessed using the Viocare food frequency questionnaire. Heritabilities and genetic correlations among the urinary traits were estimated using variance components methods.Results Samples were available from 811 individuals (344 men, 467 women; mean age 6669 years). Age, sex, and weight were significantly correlated with the majority of urinary traits. Many urine excretions (calcium, magnesium, citrate excretion) had strong evidence for heritability (P,0.01) both before and after adjusting for the identified covariates. Among significantly heritable urinary traits, genetic factors explained 20%-36% of interindividual variation after adjustment for covariates. Urinary calcium excretion was significantly genetically correlated with urinary magnesium and with urinary citrate excretion (P,0.05). Although eGFR influenced many urinary traits, controlling for eGFR did not greatly affect estimated heritabilities.Conclusions Evidence from this cohort suggests a strong heritable component to many urinary nephrolithiasis risk factors. Further study of genetic influences on urinary traits relevant for kidney stone pathogenesis is warranted.Clin J Am Soc Nephrol 9: 943-950, 2014.

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Section: Urine Collectionmentioning

confidence: 99%

Heritability of Urinary Traits That Contribute to Nephrolithiasis

Lieske

Turner

Edeh

et al. 2014

Clinical Journal of the American Society of Nephrology

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“…The risk of calcium oxalate crystallization computed as relative supersaturation for calcium oxalate was calculated with the EQUIL2 computer program based on urine composition (Werness et al, 1985).…”

Section: Sample Preparation and Analysesmentioning

confidence: 99%

Influence of a mineral water rich in calcium, magnesium and bicarbonate on urine composition and the risk of calcium oxalate crystallization

2004

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Objective: To evaluate the effect of a mineral water rich in magnesium (337 mg/l), calcium (232 mg/l) and bicarbonate (3388 mg/l) on urine composition and the risk of calcium oxalate crystallization. Design: A total of 12 healthy male volunteers participated in the study. During the baseline phase, subjects collected two 24-h urine samples while on their usual diet. Throughout the control and test phases, lasting 5 days each, the subjects received a standardized diet calculated according to the recommendations. During the control phase, subjects consumed 1.4 l/day of a neutral fruit tea, which was replaced by an equal volume of a mineral water during the test phase. On the follow-up phase, subjects continued to drink 1.4 l/day of the mineral water on their usual diet and collected 24-h urine samples weekly. Results: During the intake of mineral water, urinary pH, magnesium and citrate excretion increased significantly on both standardized and normal dietary conditions. The mineral water led to a significant increase in urinary calcium excretion only on the standardized diet, and to a significantly higher urinary volume and decreased supersaturation with calcium oxalate only on the usual diet. Conclusions: The magnesium and bicarbonate content of the mineral water resulted in favorable changes in urinary pH, magnesium and citrate excretion, inhibitors of calcium oxalate stone formation, counterbalancing increased calcium excretion. Since urinary oxalate excretion did not diminish, further studies are necessary to evaluate whether the ingestion of calcium-rich mineral water with, rather than between, meals may complex oxalate in the gut thus limiting intestinal absorption and urinary excretion of calcium and oxalate.

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“…6 The DG value at formation product was calculated as follows: DG = 0.8623 ¥ ln(SS); AP MAP = SS ¥ 1.15 ¥ 10 -13 . 1 The two peaks of saturation were noted from 08.00 to 10.30 h and from 13.00 to 18.00 h and these peak levels increased following citrate therapy. The increase in saturation with treatment in comparison with day 0 was significant on day 1, but not on day 5.…”

Section: Resultsmentioning

confidence: 92%

“…Urine pH was measured with a glass electrode and the urine volume was also measured immediately after voiding. 1 The DG value of magnesium ammonium phosphate was calculated from the 12 variables in 345 urine specimens with the two values fixed using the Equil2 program. 1 The DG value is negative for undersaturated solutions, zero for solutions at concentrations corresponding to the solubility product and positive for supersaturated solutions.…”

Section: Methodsmentioning

confidence: 99%

“…1 The DG value of magnesium ammonium phosphate was calculated from the 12 variables in 345 urine specimens with the two values fixed using the Equil2 program. 1 The DG value is negative for undersaturated solutions, zero for solutions at concentrations corresponding to the solubility product and positive for supersaturated solutions. The Bonferroni method was used for statistical comparisons between the control day (day 0) and treatment days (days 1-5).…”

Section: Methodsmentioning

confidence: 99%

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Impact of citrate therapy on the circadian rhythm of urinary magnesium ammonium phosphate saturation in normal individuals

et al. 2000

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Background: Alkaline citrate has been used widely in the prevention of stone formation. However, the risk of struvite stone during the alkalinizing therapy has not been adequately studied in terms of magnesium ammonium phosphate saturation. Methods:The circadian rhythm of the urinary saturation of magnesium ammonium phosphate was estimated by using the differential Gibbs' free energy values of magnesium ammonium phosphate before and during 5 days of treatment with sodium-potassium citrate (1 g t.i.d., 1 g q.i.d. or 3 g t.i.d.) in five healthy male volunteers. Results:The magnesium ammonium phosphate saturation varied during the day, peaking far below the solubility product between 08.00 and 10.30 h and between 13.00 and 18.00 h. The mean peak levels were increased by each treatment regimen in comparison with the control day. The mean increase on day 1 was significant between 10.30 and 23.00 h with the 3 g t.i.d. regimen, but the mean saturation still remained below the solubility product throughout the day. Conclusions:The urinary magnesium ammonium phosphate saturation appeared hard to exceed the solubility product with a high dose of alkaline citrate.

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Equil2: A Basic Computer Program for the Calculation of Urinary Saturation

Cited by 479 publications

References 13 publications

Heritability of Urinary Traits That Contribute to Nephrolithiasis

Heritability of Urinary Traits That Contribute to Nephrolithiasis

Influence of a mineral water rich in calcium, magnesium and bicarbonate on urine composition and the risk of calcium oxalate crystallization

Impact of citrate therapy on the circadian rhythm of urinary magnesium ammonium phosphate saturation in normal individuals

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