1. From the Departments of Clinical Physiology (M.J.J., L.J., J.J.H., O.T.R.), Pediatrics (K.N-S.), Clinical Chemistry (K.I.), and Medicine (T.R.), the PET Centre (O.T.R.), and the Research Centre of Applied and Preventive Cardiovascular Medicine (M.J.J.), University of Turku, Finland, and the Department of Cardiology, Prince Alfred Hospital (D.S.C.), Sydney, Australia.