Biomaterial Database

Influence of irradiation conditions on the measurement of DNA double-strand breaks by pulsed-field gel electrophoresis. 1993

M D Story, and K C Garrett, and P J Tofilon, and R E Meyn

Department of Experimental Radiotherapy, M.D. Anderson Cancer Center, Houston, TX 77030.

The induction of gamma-ray-induced DNA double-strand breaks (DSBs) determined by pulsed-field gel electrophoresis was compared in the DNA of intact Chinese hamster ovary (CHO) cells imbedded in agarose plugs, and in the isolated DNA of agarose-imbedded CHO cells that had been lysed before irradiation, to determine whether these irradiation conditions would influence their measurement. DSB-induction in irradiated cells or isolated DNA was measured as the loss of DNA from the plug compared with the unirradiated control. Chromatin protein was completely digested by the lysis buffer and as such did not affect DNA migration upon electrophoresis, whereas concentrations of EDTA as low as 10(-5) M affected the induction of DSBs in the isolated DNA. The gel plugs required several hours of washing with PBS to remove the contaminating EDTA from the lysis buffer. Once the residual EDTA was removed, DNA DSB induction as a function of dose was 70 times greater in isolated DNA than in the DNA of intact cells.

UI	MeSH Term	Description	Entries
D002588	Cesium Radioisotopes	Unstable isotopes of cesium that decay or disintegrate emitting radiation. Cs atoms with atomic weights of 123, 125-132, and 134-145 are radioactive cesium isotopes.	Radioisotopes, Cesium
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
D005720	Gamma Rays	Penetrating, high-energy electromagnetic radiation emitted from atomic nuclei during NUCLEAR DECAY. The range of wavelengths of emitted radiation is between 0.1 - 100 pm which overlaps the shorter, more energetic hard X-RAYS wavelengths. The distinction between gamma rays and X-rays is based on their radiation source.	Gamma Wave,Gamma Radiation,Nuclear X-Rays,Radiation, Gamma,X-Rays, Nuclear,Gamma Radiations,Gamma Ray,Gamma Waves,Nuclear X Rays,Nuclear X-Ray,Ray, Gamma,Wave, Gamma,Waves, Gamma,X Rays, Nuclear,X-Ray, Nuclear
D006224	Cricetinae	A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.	Cricetus,Hamsters,Hamster
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D016466	CHO Cells	CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.	CHO Cell,Cell, CHO,Cells, CHO
D016521	Electrophoresis, Gel, Pulsed-Field	Gel electrophoresis in which the direction of the electric field is changed periodically. This technique is similar to other electrophoretic methods normally used to separate double-stranded DNA molecules ranging in size up to tens of thousands of base-pairs. However, by alternating the electric field direction one is able to separate DNA molecules up to several million base-pairs in length.	Electrophoresis, Gel, Pulsed-Field Gradient,Gel Electrophoresis, Pulsed-Field,Contour-Clamped Homogeneous-Field Gel Electrophoresis,Electrophoresis, Gel, Pulsed Field,Electrophoresis, Pulsed Field Gel,Field Inversion Gel Electrophoresis,Orthogonal Field Alternation Gel Electrophoresis,Orthogonal-Field Alternation-Gel Electrophoresis,Pulsed Field Gradient Gel Electrophoresis,Pulsed-Field Gel Electrophoresis,Pulsed-Field Gradient Gel Electrophoresis,Alternation-Gel Electrophoresis, Orthogonal-Field,Contour Clamped Homogeneous Field Gel Electrophoresis,Electrophoresis, Orthogonal-Field Alternation-Gel,Electrophoresis, Pulsed-Field Gel,Gel Electrophoresis, Pulsed Field,Pulsed Field Gel Electrophoresis