1. From the Hematology Branch, Laboratory of Molecular Biology, Laboratory of Cardiac Energetics, and Light Microscopy Core Facility, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, Bethesda, MD; Laboratory of Functional and Molecular Imaging, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda, MD; and Osiris Therapeutics, Baltimore, MD