Carcinogenesis of Depleted Uranium

Abstract

Abstract : Depleted uranium (DU)-containing shrapnel was found in the wounds of several Gulf War veterans. DU may be more hazardous than other shrapnel because of its radioactivity and known toxicity to the kidney. Predictions of risk are necessary to guide the medical management of soldiers with DU-bearing wounds both now and in the future. We are determining the carcinogenicity of radioactive DU fragments in tissues relative to nonradioactive foreign-body fragments and assessing the potential for renal toxicity of DU fragments by correlating urine and kidney concentrations of U with time after implantation. DU fragments of differing sizes and shapes have been implanted in the soft tissue of rats to compare with results from animals implanted with inert metals. In this way a toxicity ratio will be determined that can be used to predict the expected response in humans from the known response of humans to relatively inert shrapnel. A pilot study was used to determine important experimental design parameters for studying the foreign-body response using this test system in animals. Parameters defined include fragment in vitro and in vivo solubility, optimal fragment size and shape for implantation, changes in the surface characteristics of fragments that could be important in carcinogenesis, and determination that fragments of DU alloyed with titanium DU(Ti) would be more desirable than nonalloyed DU based on particle solubility. A long-term carcinogenesis study of DU fragments implanted in the muscles of rats is in progress.