1. Section on Cellular Control Mechanisms, Human Tumor Cell Biology Branch, National Cancer Institute, Bethesda, Md.
2. University of Virginia Medical School, Charlottesville, Va.; formerly Clinical Associate, Section on Cellular Control Mechanisms, Human Tumor Cell Biology, National Cancer Institute, Bethesda, Md.
3. Section on Cellular Control Mechonisms, Human Tumor Cell Biology Branch, National Cancer Institute, Bethesda, Md.