Spatial Properties of Clustered Free Radicals Produced in DNA and Biodosimeters by Ionizing Radiation
EMSL Project ID
2177
Abstract
This application seeks to continue our EMSL project centered on the spatial properties of trapped free radicals in irradiated DNA and in tooth enamel, which is increasingly being used as a retrospective biodosimeter for the measurement of radiation exposure. This information on irradiated tooth enamel may allow the development of methodology to determine the average energy and type of radiation to which the enamel was exposed, thus increasing the usefulness of this material as a biodosimeter. With reference to DNA, this information is needed in order to develop a better understanding of the mechanisms involved in the production of DNA damage which may not be repaired, or may be misrepaired, in cells and thus may lead to deleterious health effects. Models incorporating the data from this project will be more accurate in their prediction of risks for such adverse health effects as cancer from exposure to low doses of radiation. The results of these studies should be of interest to DOE programs responsible for radiation safety and worker health. The specific aim of the project is to obtain measures of the dimensions of clusters of damaged molecules which include free radical intermediates, and the average number of free radicals/cluster produced in the DNA or enamel by radiation and to determine how these dimensions vary with the energy and type of impinging radiation. For DNA studies, other variables include DNA base sequence, packing and hydration. The approach for obtaining measures of cluster dimensions and number of trapped radicals is to use pulsed electron paramagnetic resonance spectroscopy (EPR) methodologies available at EMSL to study the magnetic interactions of trapped free radicals in solid DNA and purified tooth enamel irradiated at various temperatures with radiations of varying energies and types. With the appropriate pulsing sequences and applicable theory, the EPR data will allow spatial information to be derived.
Project Details
Project type
Capability Research
Start Date
2002-05-01
End Date
2002-09-04
Status
Closed
Released Data Link
Team
Principal Investigator