Inferences from the collaboration in the field of pharmaco-chemical protection and treatment of radiation injury according to the 'Intercosmos' program

Responses observed in experiments on mammals, cultured cells, and plant material have again confirmed that protectants from the group of mercaptoamines and indolyl alkylamines fail to be effective in the case of protracted radiation exposure given at 1 rad or less per minute. Under such irradiation conditions, therapeutic administration of ATP has achieved a high protective effect in dogs. Adeturone, a molecular AET-ATP combination synthesized in Bulgaria, has been tested in a large number of studies involving various exposure conditions and biological end-points. Protection was shown to be provided against acute X-rays and 630-MeV protons and chronic gamma rays in mice; bone-marrow cell colony-forming ability to be promoted; peripheral lymphocyte counts and bone marrow cellularity to be raised; fall in nucleic acid content of peripheral blood cells to be counteracted; heritable structures in mouse germ cells to be protected, as evidenced by reduced induction of chromosome translocations; and in vitro yields of peripheral lymphocyte chromosome aberrations to be lowered to a larger extent by Adeturone, than by cysteamine or cytriphos. Among the formulations based on ATP, the combination exhibiting the highest effectiveness and the widest therapeutic margin was that of ATP, AET and mexamine. (A.B.)