1. Department of Nutritional Sciences (S.B., D.S.), Madison, Wisconsin 53706-1571;
2. Wisconsin Regional Primate Research Center (J.K., R.C., W.N., K.W., S.B.), Madison, Wisconsin 53706-1571;
3. Departments of Physiology (J.K.), Madison, Wisconsin 53706-1571;
4. Medicine (R.W.), University of Wisconsin-Madison, Madison, Wisconsin 53706-1571;
5. Veterans Administration Hospital (R.W.), Geriatric Research, Education and Clinical Center, Madison, Wisconsin 53705;
6. Department of Molecular Sciences (J.R.), School of Veterinary Medicine, University of California-Davis, Davis, California 95616