1. From the Stroke Prevention Research Unit (P.M.R., S.A.G., D.P.), University Department of Clinical Neurology, Radcliffe Infirmary, Oxford, UK; Departments of Community Health Sciences and Clinical Neurosciences (M.E.), University of Calgary, Alberta, Canada; Department of Clinical Neurosciences (C.P.W.), Western General Hospital, Edinburgh, UK; and the John P. Robarts Research Institute (H.J.M.B.), London, Ontario, Canada.