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Magnesium, citrate, magnesium citrate and magnesium-alkali citrate as modulators of calcium oxalate crystallization in urine: observations in patients with recurrent idiopathic calcium urolithiasis.
Urol Res 1999; 27(2):117-26UR

Abstract

The effects of magnesium (Mg) and citrate on the metastable limit of calcium oxalate (CaOx) solubility (synonym: tolerable oxalate TO) were examined in artificial urine and in postprandial urine of male patients with idiopathic calcium urolithiasis (ICU). In artificial urine increasing pH, Mg and citrate elevate TO, decrease CaOx supersaturation only marginally, but elevate considerably free citrate; the effect of Mg alone was small in comparison with citrate alone, and the effects of both substances appeared additive. In ICU patients, matched for sex, age and CaOx supersaturation to non-stone-forming controls, TO was decreased (mean values 0.33 vs. 0.52 mM/l in controls, P < 0.05). Additional significant (P < 0.05) differences were found between ICU and controls: the former exhibited increased CaOx crystal growth, decreased crystal agglomeration time, a more acidic urinary pH, increased concentrations of free calcium and free Mg, and decreased free oxalate and free citrate. After ingestion of a urine-acidifying test meal, or this meal supplemented with either neutral Mg citrate or Mg-alkali citrate, by three groups of male ICU patients, matched for age and CaOx supersaturation, only the last-named preparation evoked an increase in TO and a decrease in crystal diameter, while the normally occurring pH decline from fasting urine was virtually abolished, and the ratios urinary Mg/citrate and calcium/citrate tended towards low values. In contrast, Mg citrate increased crystal agglomeration time, while changes in the other parameters were only insignificant. The crystals formed in urine were CaOx di- and monohydrate (by electron microscopy), and energy dispersive X-ray analysis showed calcium peaks exclusively. However, chemical analysis of crystals verified the presence not only of oxalate and calcium, but also of Mg, phosphate, citrate, and urate; moreover, these crystal constituents seemed to be influenced by Mg citrate and Mg-alkali citrate in different ways. It was concluded that (1) Mg and citrate are effectors of TO in artificial and natural urine; (2) in ICU, low TO and other disturbed CaOx crystallization parameters appear related to the prevailing low urinary pH and low free citrate; (3) Mg-alkali citrate inhibits CaOx crystallization, probably via actions of the citrate, but not the Mg. Because of the eminent role of Mg in human health and ICU, further studies on crystallization after oral intake of Mg in the form of citrate are warranted.

Authors+Show Affiliations

University Hospital Department of Surgery, Erlangen, Germany.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Clinical Trial
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

10424393

Citation

Schwille, P O., et al. "Magnesium, Citrate, Magnesium Citrate and Magnesium-alkali Citrate as Modulators of Calcium Oxalate Crystallization in Urine: Observations in Patients With Recurrent Idiopathic Calcium Urolithiasis." Urological Research, vol. 27, no. 2, 1999, pp. 117-26.
Schwille PO, Schmiedl A, Herrmann U, et al. Magnesium, citrate, magnesium citrate and magnesium-alkali citrate as modulators of calcium oxalate crystallization in urine: observations in patients with recurrent idiopathic calcium urolithiasis. Urol Res. 1999;27(2):117-26.
Schwille, P. O., Schmiedl, A., Herrmann, U., Fan, J., Gottlieb, D., Manoharan, M., & Wipplinger, J. (1999). Magnesium, citrate, magnesium citrate and magnesium-alkali citrate as modulators of calcium oxalate crystallization in urine: observations in patients with recurrent idiopathic calcium urolithiasis. Urological Research, 27(2), pp. 117-26.
Schwille PO, et al. Magnesium, Citrate, Magnesium Citrate and Magnesium-alkali Citrate as Modulators of Calcium Oxalate Crystallization in Urine: Observations in Patients With Recurrent Idiopathic Calcium Urolithiasis. Urol Res. 1999;27(2):117-26. PubMed PMID: 10424393.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Magnesium, citrate, magnesium citrate and magnesium-alkali citrate as modulators of calcium oxalate crystallization in urine: observations in patients with recurrent idiopathic calcium urolithiasis. AU - Schwille,P O, AU - Schmiedl,A, AU - Herrmann,U, AU - Fan,J, AU - Gottlieb,D, AU - Manoharan,M, AU - Wipplinger,J, PY - 1999/7/29/pubmed PY - 1999/7/29/medline PY - 1999/7/29/entrez SP - 117 EP - 26 JF - Urological research JO - Urol. Res. VL - 27 IS - 2 N2 - The effects of magnesium (Mg) and citrate on the metastable limit of calcium oxalate (CaOx) solubility (synonym: tolerable oxalate TO) were examined in artificial urine and in postprandial urine of male patients with idiopathic calcium urolithiasis (ICU). In artificial urine increasing pH, Mg and citrate elevate TO, decrease CaOx supersaturation only marginally, but elevate considerably free citrate; the effect of Mg alone was small in comparison with citrate alone, and the effects of both substances appeared additive. In ICU patients, matched for sex, age and CaOx supersaturation to non-stone-forming controls, TO was decreased (mean values 0.33 vs. 0.52 mM/l in controls, P < 0.05). Additional significant (P < 0.05) differences were found between ICU and controls: the former exhibited increased CaOx crystal growth, decreased crystal agglomeration time, a more acidic urinary pH, increased concentrations of free calcium and free Mg, and decreased free oxalate and free citrate. After ingestion of a urine-acidifying test meal, or this meal supplemented with either neutral Mg citrate or Mg-alkali citrate, by three groups of male ICU patients, matched for age and CaOx supersaturation, only the last-named preparation evoked an increase in TO and a decrease in crystal diameter, while the normally occurring pH decline from fasting urine was virtually abolished, and the ratios urinary Mg/citrate and calcium/citrate tended towards low values. In contrast, Mg citrate increased crystal agglomeration time, while changes in the other parameters were only insignificant. The crystals formed in urine were CaOx di- and monohydrate (by electron microscopy), and energy dispersive X-ray analysis showed calcium peaks exclusively. However, chemical analysis of crystals verified the presence not only of oxalate and calcium, but also of Mg, phosphate, citrate, and urate; moreover, these crystal constituents seemed to be influenced by Mg citrate and Mg-alkali citrate in different ways. It was concluded that (1) Mg and citrate are effectors of TO in artificial and natural urine; (2) in ICU, low TO and other disturbed CaOx crystallization parameters appear related to the prevailing low urinary pH and low free citrate; (3) Mg-alkali citrate inhibits CaOx crystallization, probably via actions of the citrate, but not the Mg. Because of the eminent role of Mg in human health and ICU, further studies on crystallization after oral intake of Mg in the form of citrate are warranted. SN - 0300-5623 UR - https://www.unboundmedicine.com/medline/citation/10424393/Magnesium_citrate_magnesium_citrate_and_magnesium_alkali_citrate_as_modulators_of_calcium_oxalate_crystallization_in_urine:_observations_in_patients_with_recurrent_idiopathic_calcium_urolithiasis_ L2 - https://dx.doi.org/10.1007/s002400050097 DB - PRIME DP - Unbound Medicine ER -