David Brown at the Washington Post ... does a terrific job of explaining how the modestly toxic substance, melamine, can cause renal failure when combined with cyanuric acid. Not widely reported in the press is the fact that cyanuric acid, another nitrogen-rich compound, has also been found to contaminate some wheat gluten and wheat flour from China.
Gout works in much the same way, when foods rich in purine are consumed and inadequately excreted from the body via the kidneys. Uric acid crystallizes in the joints, usually in the big toe for some reason and causes immense pain aka tophus. It makes sense, since needle-like crystals are spontaneously forming there.