1. Division of Hematology-Oncology, Department of Medicine, New England Medical Center Hospital, Boston, Massachusetts; U.S.A.
2. Cancer Research Center, Tufts University School of Medicine, Boston, Massachusetts; U.S.A.
3. Kundsin Laboratory, Inc., Brigham and Women's Hospital, Harvard Medical Schqol; Boston, Massachusetts; U.S.A.
4. Department of Biochemistry and Pharmacology, Tufts University School of Medicine, Boston, Massachusetts, Boston, Massachusetts; U.S.A.