1. National Cancer Institute and Clinical Center, National Institutes of Health, Bethesda, Md. 20014, and George Washington University, Washington, D. C. 20006.
2. Cytogenetic Oncology. Tumor Cell Biology Branch. Experimental Therapeutics. National Cancer institute. National institutes of Health. Bethesda. Md. 20014.
3. Hematology Service. Clinical Pathology Department. Clinical Center. National institutes of Health. Bethesda. Md. 20014.
4. Radiation Branch. Laboratory of Physiology. National Cancer institute. National institutes of Health. Bethesda. Md. 20014.
5. Tumor Cell Biology Branch, Experimental Therapeutics, National Cancer institute, National institutes of Health, Bethesda, Md. 20014.
6. George Washington Hospital. Washington. D. C. 20037.