1. Departments of Pathology, Pediatrics, and Neurology and Liver Research Center, Albert Einstein College of Medicine, Bronx, New York 10461
2. Departments of Pathology and Pediatric Neurology, Children's Hospital of Michigan, and Wayne State University School of Medicine, Detroit 48201
3. Departments of Cell Biology and Medicine and Kaplan Cancer Center, New York University School of Medicine, New York 10016
4. John F. Kennedy Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205
5. Rockefeller University, New York 10021