Subacute and late cardiovascular sequelae to low doses of gamma radiation

¹ Department of Pharmacology and Pathology, College of Medicine, University of Vermont, Burlington, Vermont
² Departments of Pharmacology and Pathology, College of Medicine, University of Vermont, Burlington, Vermont

A battery of in vivo and in vitro tests of cardiovascular performance were used to assess the effects of whole-body gamma radiation (cobalt-60) upon the cardiovascular system of dogs. A new method for study of the pressure-volume relations of isolated surviving arteries is described. Groups of six beagles were exposed to 30 r and 100 r 22 months before death and compared with littermate controls. No differences between irradiated and control dogs could be demonstrated. Eight mongrel dogs received 300 r 30 days before death and were compared with five mongrel controls. The only significant difference observed was in the pressure-volume curves of arteries from irradiated dogs, these vessels having a greater initial tone than control arteries. It is concluded that 30 r and 100 r of whole-body gamma radiation have no demonstrable effect upon the cardiovascular system of dogs irradiated 22 months before study, but that 300 r of gamma radiation does produce a significant abnormality of blood vessels.