1. From the Mayo Clinic (J.F.M., K.C., T.G.B.), Jacksonville, FL; University of Maryland School of Medicine (B.L.), Baltimore; CREST-2 Executive Committee (G.R.), Jackson, WY; Medical University of South Carolina (T.N.T.), Charleston; University of Alabama at Birmingham (V.J.H., G.H.); and National Institute of Neurological Disorders and Stroke (R.T.B.), Bethesda, MD.