1. From the Jobst Vascular Research Laboratories, Department of Surgery, Section of Vascular Surgery, University of Michigan, Ann Arbor (J.L.E., K.K.H., G.A., I.S., J.W.F., M.P.D., K.J.R., D.T.W., P.K.H., J.C.S., G.R.U.), and the Department of Surgery, Section of Vascular Surgery, Washington University School of Medicine, St. Louis, Mo (T.L.E., R.W.T.).