1. Department of Veterinary Science and Microbiology1 and
2. Radiobiology Division, National Cancer Center Research Institute, Tokyo, Japan 104-00452;
3. Radiobiology Section, DLR, Institute of Aerospace Medicine, Cologne, Germany3; and
4. Lunar and Planetary Laboratory,4 University of Arizona, Tucson, Arizona 85721;
5. Department of Biochemistry, University of Connecticut Health Center, Farmington, Connecticut 060325