The role of glycoproteins in calcium oxalate crystal development.
OBJECTIVE
To assess the effects of a glycoprotein (mucine) on calcium oxalate crystal development in different conditions and situations, to clarify some of its possible effects.


METHODS
Crystallization was assessed using a batch system in presence of mucine suspensions, by kinetic-turbidimetric measurements, and using a flow system in the presence of retained agglomerates of mucine, evaluating the precipitated calcium oxalate.


RESULTS
In batch conditions low mucine concentrations (<15 mg/L) inhibited calcium oxalate nucleation and higher concentrations (<250 mg/L) inhibited calcium phosphate nucleation, whereas at high concentrations there was also promotion. The presence of an aggregate of mucine in the flow system provoked calcium oxalate monohydrate crystallization at 0.691 microg/h per mg of mucine. In flow conditions pyrophosphate at 11.5 micromol/L caused a decrease of 84% in the calcium oxalate crystallized on mucine, 1.32 mmol/L of citrate a decrease of a 83%, 20 mg/L of pentosan polysulphate a decrease by 80%, and 7.58 micromol/L phytate totally prevented the crystallization of calcium oxalate on mucine.


CONCLUSIONS
All substances inhibiting calcium oxalate crystallization with the capacity to interact with calcium ions also have crystallization promoting properties when they are at sufficiently high concentrations, because of their capacity to form agglomerates or the insolubility of their calcium salts.
Grases
Felix
F
Laboratory of Renal Lithiasis Research, Institute of Health Sciences Research (IUNICS), University of Balearic Islands. Palma de Mallorca, Spain. fgrases@uib.es
Isern
Bernat
B
Perelló
Joan
J
Costa-Bauzá
Antonia
A
D002129:Calcium Oxalate / Q000737:chemistry*; D003460:Crystallization; D008855:Microscopy, Electron, Scanning; D009077:Mucins / Q000494:pharmacology*; D010426:Pentosan Sulfuric Polyester / Q000494:pharmacology; D014556:Urine
D009077:Mucins; D002129:Calcium Oxalate; D010426:Pentosan Sulfuric Polyester