Some Molecular and Cellular Effects of Heavily Ionizing Radiations*

Heavily ionizing particles and their biological effects have been the subject of vigorous laboratory studies for the past several years due to increased interest in the densely ionizing components of interplanetary cosmic rays and to the availability of heavy-ion accelerators.These studies have been approached from several viewpoints.Among these are the basic effects of radiations on macromolecules, living cells, and multicellular systems; the possible part these particles may have played in the synthesis of organic matter in the primitive atmosphere of the Earth; and application of these studies to therapy and problems of protecting astronauts and people working near high-energy accelerators.Since the first acceleration of carbon ions in 1939l~ and the subsequent initial use of such accelerated particles in 1953,3 most of the quantitative studies have been carried out at the heavy-ion linear accelerators of Yale University and at the University of California Lawrence Radiation Laboratory in Berkeley.Since recent reviews have been written only a few months ago by Tor B r ~s t a d , ~ C. Tobias et d16 and Franklin Hutchin-we shall restrict ourselves to a description of the present status of macromolecular research with heavy ions and a comparative account of the cellular effect.