[1] Univ Iowa, Interdisciplinary Grad Program Human Toxicol, Iowa City, IA 52242 USA
[2] Univ Iowa, Free Rad & Radiat Biol Program, Dept Radiat Oncol, Iowa City, IA 52242 USA
[3] Univ Iowa, Dept Surg, Iowa City, IA 52242 USA
[4] Vet Affairs Med Ctr, Iowa City, IA 52246 USA