1. Veterans Affairs Medical Center, Washington, District of Columbia
2. George Washington University School of Medicine and Health Sciences, Washington, District of Columbia
3. University of Maryland School of Medicine, Baltimore
4. Georgetown University School of Medicine, Washington, District of Columbia
5. MedStar Health Research Institute, Washington, District of Columbia
6. Indiana University Center for Aging Research, Indianapolis
7. Regenstrief Institute, Inc., Indianapolis, Indiana
8. Indiana University School of Medicine, Indianapolis