1. From the Section of Vascular Surgery, Jobst Vascular Research Laboratory, Department of Surgery (P.K.H., A.V., S.D., C.B.D., J.E., P.S., P.T., G.R.U., T.W.W.), the Division of Pulmonary Medicine, Department of Medicine (D.A.A.), and the Department of Pathology (S.L.K.), University of Michigan Medical School, Ann Arbor, Mich.