1. Department of Pathology, Johns Hopkins University, Baltimore, MD 21205, USA.
2. Center for Organogenesis and Trauma, Department of Surgery, University of Texas Southwestern, Dallas, TX 75390, USA.
3. Department of Orthopaedics and Traumatology, University of Verona, Verona 37129, Italy.
4. Department of Neuroscience, Center for Advanced Pain Studies, University of Texas at Dallas, Dallas, TX 75080, USA.
5. Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Botnar Research Centre, Windmill Road, Oxford OX3 7LD, UK.
6. Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21208, USA.
7. Department of Orthopaedics, University of Maryland, Baltimore, MD 21205, USA.
8. Baltimore Veterans Administration Medical Center, Baltimore, MD 21201, USA.