Indirect Formation of Urinary Solids

There are essentially three types of urinary solids precipitate (amorphous material), crystals, and calculi. The distinction between crystals and calculi, especially in 

TABLE 19.1. Substances Leading to the Formation of Urinary Solids 

Endogenous Substances (Normal Urinary Constituents) Synthetic Chemicals and Pharmaceuticals 

Urates and uric acid Radiographic media (meglumine diatrizoate) 

In many of the rodent models involving formation of urinary solids, there is associated cytotoxicity, regenerative proliferation, and ultimately the induction of tumors of the urothelium, usually of the urinary bladder but occasionally of the kidney pelvis or ureters (Shirai et al. 1989). Cytotoxicity and regenerative 

---