1. From the Departments of Medicine (O.-P.P., P.N., I.N., T.R., J.V.) and Clinical Physiology (O.T.R.) and the Turku PET Centre (J.K.), Turku University, Turku, Finland; National Public Health Institute, Helsinki, Finland (K.P., C.E.); Department of Medicine (M.-R.T.), Helsinki University, Helsinki, Finland; and Research Institute for Brain and Blood Vessels-Akita (H.I.), Akita, Japan.