1. From the Vascular Biology Group at the Robarts Research Institute (C.A.A., C.G.S., S.L., Z.N., J.G.P., M.W.H.), and the Departments of Medicine (C.G.S., R.A.H., J.G.P., M.W.H.) and Biochemistry (R.A.H., J.G.P., M.W.H.), University of Western Ontario, London, Ontario, Canada.