1. From the Vascular Sciences Section (A.S., N.H.D., G.M.B., M.J., P.C.E., J.C.M., D.O.H., J.J.B., and A.M.R.), National Heart and Lung Institute, Imperial College London, London, England; and Kennedy Institute of Rheumatology (L.M. and E.M.P.), Imperial College London, London, England.