title: Calcium phosphate in catheter encrustation.
abstract: Encrusted catheters from nine female patients were the source of samples of deposits which were examined by X-ray diffraction, atomic absorption spectroscopy, infra-red spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. In eight samples the only crystalline phase which could be clearly distinguished by X-ray diffraction was ammonium magnesium orthophosphate hexahydrate, NH4MgPO4 X 6H2O, which occurs naturally as the mineral struvite. However, atomic absorption spectroscopy revealed an appreciable concentration of calcium in all samples. Calcium phosphates have previously been detected in catheter deposits. Infra-red and EXAFS spectra were consistent with the calcium phosphate being present as a poorly crystalline hydroxyapatite. Thus the deposits appear to consist of a mixture of crystalline struvite and a form of hydroxyapatite which is not fully crystalline.
mesh_terms: D002408:Catheters, Indwelling; D003460:Crystallization; D017886:Durapatite; D005260:Female; D006801:Humans; D006882:Hydroxyapatites / Q000032:analysis*; D008274:Magnesium / Q000032:analysis*; D017616:Magnesium Compounds; D010710:Phosphates / Q000032:analysis*; D013057:Spectrum Analysis; D000069877:Struvite; D014546:Urinary Catheterization
chemical_list: D006882:Hydroxyapatites; D017616:Magnesium Compounds; D010710:Phosphates; D017886:Durapatite; D000069877:Struvite; D008274:Magnesium