title: New measure of DNA repair in the single-cell gel electrophoresis (comet) assay.
abstract: Since its introduction by Ostling and Johanson [1984; Biochem Biophys Res Commun 123:291-298] and independent modifications by Singh et al. [1990; Exp Cell Res 175:184-191] and Olive et al. [1988; Radiat Res 112:86-94], the comet assay has been widely used in genetic toxicology, environmental biomonitoring, molecular and human epidemiology, and clinical investigations. There are still several issues to be resolved before the comet assay is accepted as a standard assay for detecting DNA damage and repair in a single cell. One of the major issues is the proper quantification of DNA damage/repair. The aim of this article is to develop a new quantitative measure of DNA damage/repair which is represented in the dose-time-response surface. We propose to use the second derivative (2D) of the dose-time-response surface for measuring DNA repair activity. This approach enables us to represent the DNA repair activity of cells exposed to a DNA-damaging agent with a single number by combining all the information of a dose-time-response experiment. The computation procedure includes the application of linear regression. An SAS/AF-based program, "Comet Assay," was developed for this computation and is freely available on the Internet. We considered the response of each of four DNA damage parameters: tail moment, tail length, tail DNA, and tail inertia for constructing the dose-time-response surface. Using data from 25 patients, we observed that 2Ds based on tail moment and tail DNA were highly correlated and that tail inertia might provide information on a somewhat different aspect of DNA damage/repair.
authors.affiliation: Department of Applied Statistics, Yonsei University, Seoul, South Korea. bskim@yonsei.ac.kr
authors.forename: Byung-Soo
authors.initials: BS
authors.lastname: Kim
authors.forename: Jin Joo
authors.initials: JJ
authors.lastname: Park
authors.forename: Lutz
authors.initials: L
authors.lastname: Edler
authors.forename: Dietrich
authors.initials: D
authors.lastname: Von Fournier
authors.forename: Wulf
authors.initials: W
authors.lastname: Haase
authors.forename: Marie-Luise
authors.initials: ML
authors.lastname: Sautter-Bihl
authors.forename: Florian
authors.initials: F
authors.lastname: Gotzes
authors.forename: Heinz Walter
authors.initials: HW
authors.lastname: Thielmann
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics; D020552:Comet Assay; D004249:DNA Damage; D004260:DNA Repair; D006801:Humans