Inhibitors of Calcium Oxalate and Calcium Phosphate Crystal Formation in Urine — A Critique and Reappraisal
Previous studies of the role of inhibitors of calcium oxalate and calcium phosphate crystal formation in urine have usually been performed either in relatively simple aqueous solutions or by addition of dilute urine samples to solutions supersaturated for calcium oxalate or phosphate1–4. These experiments however are open to serious objections: 1) Urine contains macromolecular promoters of crystal formation, probably uromucoids5, which should be included but have previously been excluded, and 2) the effect of certain inhibitors, notably pyrophosphate, citrate and methylene blue on calcium oxalate and calcium phosphate crystal formation is much less in whole urine than in simple inorganic solutions6. Even the studies of whole urine have not been physiological because they relied on addition of calcium and oxalate (or phosphate) to urine and this procedure can lead to abnormal crystal habits7.
KeywordsMethylene Blue Chondroitin Sulphate Crystal Formation Calcium Oxalate Calcium Oxalate Crystal
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