1. Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104.
2. Division of Cardiology, Department of Clinical Studies, Veterinary Hospital of the University of Pennsylvania, Philadelphia, PA 19104.
3. Division of Medical Genetics, Gene Therapy Program, University of Pennsylvania School of Medicine, Philadelphia, PA 19104.
4. Department of Molecular Genetics and Microbiology, Gene Therapy Center, University of Massachusetts School of Medicine, Worcester, MA 01605.