Biomaterial Database

Calibration of pulsed field gel electrophoresis for measurement of DNA double-strand breaks. 1990

D D Ager, and W C Dewey

Radiation Oncology Research Laboratory, University of California, San Francisco 94143.

The pulsed field gel electrophoresis (PFGE) assay was calibrated for the measurement of X-ray-induced DNA double-strand breaks in Chinese hamster ovary (CHO) cells. Calibration was conducted by incorporating [125I]deoxyuridine into DNA, which induces one double-strand break for every disintegration that occurs in frozen cells. Based on the percentage of the DNA migrating into the gel, the number of breaks/dalton/Gy was estimated to be (9.3 +/- 1.0) x 10(-12). This value is close to (10 to 12) x 10(-12) determined by neutral filter elution using similar cell lysis procedures at 24 degrees C and at pH 8.0. Also, the estimate is in good agreement with the value of (11.7 +/- 2) x 10(-12) breaks/dalton/Gy as measured in Ehrlich ascites tumour cells using the neutral sucrose gradient method (Blöcher 1988), and (6 to 9) x 10(-12) breaks/dalton/Gy as measured in mouse L and Chinese hamster V79 cells using neutral filter elution (Radford and Hodgson 1985).

UI	MeSH Term	Description	Entries
D007457	Iodine Radioisotopes	Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.	Radioisotopes, Iodine
D002138	Calibration	Determination, by measurement or comparison with a standard, of the correct value of each scale reading on a meter or other measuring instrument; or determination of the settings of a control device that correspond to particular values of voltage, current, frequency or other output.	Calibrations
D004247	DNA	A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).	DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D004249	DNA Damage	Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.	DNA Injury,DNA Lesion,DNA Lesions,Genotoxic Stress,Stress, Genotoxic,Injury, DNA,DNA Injuries
D004586	Electrophoresis	An electrochemical process in which macromolecules or colloidal particles with a net electric charge migrate in a solution under the influence of an electric current.	Electrophoreses