STUDIES ON CALCIUM OXALATE CRYSTAL FORMATION OF UROLITHIASIS
1987 Volume 78 Issue 2 Pages 203-217
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1987 Volume 78 Issue 2 Pages 203-217
Urinary stone develops through the process of growth and aggregation of urinary crystalline substances. Therefore, it is considered important to quantify urinary crystals. I recently devised a system composed of a coulter counter model ZBI, a coulter channelyzer C-100 and microcomputer for measuring calcium oxalate (CaOx) crystals accurately and easily. In a preliminary study this system showed a very good reproducibility. By this new system I investigated the amount and size of CaOx crystals in healthy subjects and urinary stone formers on various diets (standard, high protein, high calcium, high oxalate, high protein-high oxalate, high calcium-high oxalate), in an attempt to elucidate the mechanism of CaOx crystal formation.
The results obtained are as follows:
1) Urinary CaOx crystals were detected more frequently in the stone formers than in the normals, except on a high protein diet. The detection ratio was most increased by the intake of oxalate. The diet supplemented with calcium or portein alone had no influence upon the detection ratio.
2) The amount of crystals formed was greater in the subjects on oxalate loading diets than in those on non-oxalate diets and also in the stone formers than in the normals.
3) The number of crystals formed was not different between the stone fomers and the normals. Therefore, the relative affluence of urinary crystals in stone formers indicated that each of the crystals found in their urine was larger than that in the urine of the normal subjects.
4) The formation of urinary CaOx crystals depended strongly upon urinary oxalate levels in both the patient group and the normal group. Urinary calcium levels also had some bearing on crystal formation in the stone formers but not at all in the normals.
5) Citrate and magnesium are known as crystallization inhibitors. There may be some other substances that fall under this category.
6) Urinary CaOx crystals were increased quantitatively in association with elevated urinary oxalate levels. In addition, the increase was dependent upon calcium levels to some extent in the stone formers.
