STUDY OF THE EFFECTS OF DIFFERENT SUBSTANCES ON THE EARLY STAGES OF PAPILLARY STONE FORMATION

We have studied the early stages of calcium oxalate monohydrate (COM) crystallization, mainly heterogeneous nucleation, on fixed particles. Experiments were performed using a flow system that closely simulates the human renal conditions related to COM heterogeneous nucleation. Th e effects of citrate, phytate, aescin and glycyrrhinic acid in the COM heterogeneous nucleation on different solid surfaces as calcium phosp hate, a mixture of mucin and calcium phosphate and wax were studied. T he presence of citrate at normal urinary concentrations (1.85 . 10(-3) M) totally inhibited the development of COM crystals only on the most hydrophobic assayed material (wax). Saponins (aescin and glycyrrhinic acid) only exhibited important inhibitory effects of COM crystallizat ion on the hydrophobic wax substrate but in no case the formation of C OM crystals was totally prevented. Phytate exerted the most remarkable effects on the heterogeneous nucleation of COM crystals, thus, when i t was present at 1.43 . 10(-7) M, it totally prevented the development of COM crystals on the three assayed solid substrates.