Crystallization in the nephron
| Autor: | Inge Højgaard, Hans-Göran Tiselius |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Calcium Phosphates
Macromolecular Substances Urology Inorganic chemistry Nucleation Calcium oxalate chemistry.chemical_element Crystal growth Nephron Calcium In Vitro Techniques Models Biological Oxalate law.invention chemistry.chemical_compound law medicine Animals Humans Crystallization Kidney Tubules Collecting Supersaturation Calcium Oxalate Nephrons medicine.anatomical_structure chemistry Urinary Calculi |
| Zdroj: | Urological research. 27(6) |
| ISSN: | 0300-5623 |
| Popis: | Recent experimental studies on the crystallization of calcium salts at different nephron levels support the theory that the initial formation of calcium concrements starts with an intratubular crystallization of calcium phosphate (CaP) and calcium oxalate (CaOx). CaP seems to be the initial crystallization product in pure CaP and mixed calcium phosphate–calcium oxalate (CaPCaOx) concrements, with the formation of CaP crystals at a nephron level above the collecting duct. Urinary macromolecules and cellular degradation products most probably promote this process. During the passage through the collecting duct, CaP might partly or completely dissolve at the lower pH encountered there. This might result in an increased concentration of calcium and hence an increased supersaturation with CaOx, which in turn can bring about a heterogeneous nucleation of CaOx on or around preformed CaP crystals or crystal aggregates. The final result will be mixed CaOxCaP or pure CaOx concrements. Pure CaOx concrements might also be the result of an initial CaOx crystallization at nephron levels above or in the collecting duct under conditions with a high urinary excretion of oxalate. Whether intratubular crystallization of calcium salts results in the formation of small harmless crystals excreted with urine or calcium stones appears to be determined by a complex process, involving kinetic factors that influence crystal growth and crystal aggregation and crystal retention. |
| Databáze: | OpenAIRE |
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