Protection through parabiosis against the lethal effects of exposure to large doses of x-rays.

Parabiotic rat pairs with a skin-vascular anastomosis were used to test whether shielding of one member of the pair would protect the irradiated partner against exposure to very large doses of x-rays (1200 to 2400 roentgens). Except with the lowest dose, all unshielded, irradiated pairs or single irradiated animals died before 5 days had elapsed. In contrast, irradiated rats that had a shielded parabiont partner survived the 5-day period and many survived beyond 30 days. This is interpreted as protection against the acute intestinal death that normally occurs in the dose range investigated.