Glutaraldehyde is the most widely used agent for fixing biological tissues to be as bioprostheses and there are currently a number of commercially available glutaraldehyde-fixed bioprosthetic devices, such as, heart valves of porcine origin having support frames or stents (Carpentier-Edwards??? Stented Porcine Bioprosthesis; Baxter Healthcare Corporation; Edwards CVS Division, Irvine, Calif. 92714