Trimagnesium orthophosphate in renal calculi

We recently described a new component of calculi, trimagnesium orthophosphate. In a microscopical study of thin sections from 3500 urinary calculi we detected this compound in 14 stones, all of which contained struvite. New data suggest that trimagnesium orthophosphate is a transformation product of struvite. This well-crystallized substance was always detected a few days after the surgical extraction of struvite kidney stones, in contrast to the newberyite that appears on the surface of very old removed stones or after long exposure of stones to the atmosphere

Monosodium Urate in Urinary Calculi

In 3,000 calculi, monosodium urate was detected in 50 cases (1.66%). Infrared frequencies of monosodium urate are reported. In thin sections it appeared as long and thin fan-shaped or feather-like arranged crystals. Six calculi had monosodium urate as the sole component but all other cases were of mixed composition, with whewellite as the main secondary substance. The relative scarcity of monosodium urate cannot be explained by its high aqueous solubility because in urine the solubility decreases with increasing sodium concentration. Monosodium urate should be suspected in radiolucent calculi with neutral or light alkaline reaction and high uric acid and sodium concentrations in the patient’s urine.Peer reviewe