1. Department of Pathology, Tufts University School of Medicine and Veterinary Medicine, Boston, Massachusetts 02111
2. Department of Medicine, Tufts University School of Veterinary Medicine
3. Laboratory for Carbohydrate Research, Massachusetts General Hospital, Boston 02114
4. Department of Biochemistry, Eunice Kennedy Shriver Center for Mental Retardation, Waltham, Massachusetts 02254