Fig. 1.

Aortic histology in control and uremic rats fed a 23% protein and 1.06% phosphorus diet. Aortas were stained by the von Kossa method, in which calcium phosphate appears black. No calcification was observed in aortas from control, nonuremic rats (A), and in uremic aortas with a normal Ca content (B). Aortas with increased calcium content exhibited both patchy (C) and diffuse, circumferential (D) calcification restricted to the medial layer. The same magnification was used for all images.