1. From the Department of Medicine (L.L.D., Y.T., K.L.N., T.H.), Department of Physiology (L.L.D., Y.T.), Department of Bioengineering (L.L.D., T.H.), Department of Orthopaedic Surgery (Y.T.), Department of Molecular & Medical Pharmacology (J.T.L.), and Crump Institute for Molecular Imaging (J.T.L.), UCLA and the Greater Los Angeles Veterans Administration.