Structure-function relations in radiation damaged DNA.

Abstract

The most important biological effects of exposure to ionizing radiation can be related to a variety of changes in cell function. Some of these changes can produce cell death, but others lead to less final deleterious effects such as carcinogenesis or altered cell function as a result of energy deposition in the biological system. All the changes in cell function can be linked to DNA damage, with the double-strand break and the radiation-induced mutations causing most of the lethal damage. Increasingly more accurate and direct measurements in radiation dosimetry, as discussed at this Conference, and the understanding provided by the theories and formulations of condensed matter physics, also presented and discussed at great length at this meeting, have offered important insight into the parameters and measurable outcomes of exposure to ionizing radiation. These are enhanced by findings, such as those presented at this Conference by Clemens von Sonntag, that emerge from radiochemistry measurements in vitro of chemical changes produced by radiation exposure. Also as described at this conference by Aloke Chatterjee and Herwig Paretzke, computational simulations based on Monte Carlo algorithms have been developed to explore the parameters of the energy deposition processes and their consequences in models of the biological systems. But a clear, mechanistic link between the physical processes and the biological consequences remains somewhat elusive, suggesting that it will be necessary to know and understand first the sequence of events that lead from energy deposition of radiation in condensed matter to the biophysical and biochemical processes that occur at the level of cellular DNA.