1. From the Gladstone Institute of Cardiovascular Disease (J.F., S.P.A.M., S.T., R.Q., J.M.T., S.G.Y.), San Francisco; the Cardiovascular Research Institute (J.F., S.P.A.M., J.M.T., S.G.Y.), University of California, San Francisco; the Lawrence Berkeley Laboratory (R.M.K.), University of California, Berkeley; and the Departments of Physiology (J.M.T.) and Medicine (S.G.Y.), University of California, San Francisco.