1. Hematology-Oncology Division, Department of Medicine, New England Deaconess Hospital, Boston, Massachusetts 02215
2. Laboratory of Tumor Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20205
3. Department of Cell Biology, Litton Bionetics, Inc., Kensington, Maryland 20895
4. Program Resources Inc., Frederick Cancer Research Facility- National Cancer Institute, Frederick, Maryland 21701