CHAPEL HILL - Canadian scientists collaborating with a University of North Carolina at Chapel Hill researcher have developed the most precise test yet for genetic damage caused by ionizing radiation and cancer-causing chemicals.
The new test promises to be extremely useful because it is some 10,000 to 100,000 times more sensitive than other assays, the scientists say. Experiments with the technique also suggest doctors soon may be able to boost the body's ability to repair genetic injuries.
"Potentially, this assay could measure clinically relevant damage from ionizing radiation even in a clinical situation," said Dr. Steven A. Leadon, professor of radiation oncology at the UNC-CH School of Medicine. "Before long, we also may be able to monitor the effects of irradiating tumors much better than we can now."
A report on the research appears in the May 15 issue of the journal Science. Besides Leadon, a member of the UNC Lineberger Comprehensive Cancer Center, authors are Drs. X. Chris Le, James Z. Xing, Jane Lee and Michael Weinfeld of the University of Alberta.
Ionizing radiation kills cells by breaking or otherwise disrupting segments of genetic material known as DNA, Leadon said. But currently used methods of measuring such damage are not sensitive enough to assess environmental radiation effects. Sometimes testing techniques themselves harm DNA.
"Our new technique employs antibodies that recognize specific forms of DNA damage," Le said. "Those antibodies are then linked to other antibodies that give off fluorescent light and also attach to the damaged DNA."
Scientists feed that mixture of DNA and antibodies through a tiny glass
tube to undergo a process called capillary electrophoresis, which Dr. James
Jorgenson, professor of chemistry at UNC-CH, pioneered more than a decade ago. A
laser beam passes across the tube illuminating the sample, and electronic
equipment then monitors the resul
Contact: David L. Williamson
University of North Carolina at Chapel Hill