Affiliation: | 1. Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892;2. Department of Orthopaedic Surgery and Center for Cellular and Molecular Engineering, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15232 |