Tissue DonorsAltruismDeltaretrovirus InfectionsDeltaretrovirus AntibodiesNucleic Acid Amplification TechniquesGames, ExperimentalCost SharingInsurance, Pharmaceutical ServicesCooperative BehaviorInsurance CoverageUnited StatesBlood DonorsLiving DonorsTissue and Organ ProcurementOrgan TransplantationMultiple Organ FailureOrgan SizeOrgan SpecificityOrgan of CortiTissue and Organ HarvestingGraft SurvivalLiver TransplantationBrain DeathKidney Transplantation