Modification of End-groups in DNA Strand Breaks of Irradiated Thymocytes during Early Repair

Lennartz, Manfred; Coquerelle, Thérèse; Hagen, U.

doi:10.1080/09553007514550921

Cited by 22 publications

(6 citation statements)

References 2 publications

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“…For singlestrand breaks the half-time of repair measured for component I (table 1) is in accordance with the half-times reported in the literature being in the range of 2 to 10 min. In contrast, strand breaks resulting from alkali labile sites are not repaired at all (Lennartz et al 1975) or at a very low rate of the order of hours (Matsudaira et al 1977). But it should be noted that these experiments were carried out after extremely high doses ranging from 500 to 1400Gy.…”

Section: Discussionmentioning

confidence: 91%

Three Classes of DNA Strand Breaks Induced by X-irradiation and Internal β-rays

Dikomey

Franzke

1986

International Journal of Radiation Biology and Related Studies

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Repair kinetics of DNA strand breaks were investigated after exposing exponentially growing CHO cells to X-radiation or to internal beta-rays from incorporated tritium, respectively. DNA strand breaks were analysed by the alkaline unwinding technique followed by chromatography on hydroxyapatite. For either type of radiation, the repair kinetics are statistically best described by a sum of three exponential components. The half-times determined are tau I approximately 2 min, tau II approximately 20 min and tau III approximately 170 min; they are identical for both types of radiation. But the initial fractions of the components are different for X- and internal beta-rays; X-rays; fI = 0.70, fII = 0.25, fIII = 0.05; internal beta-rays: fI = 0.40, fII = 0.40, fIII = 0.20. Components I and II are considered to represent the repair of two different classes of single-strand breaks and component III the repair of double-strand breaks. Two alternative interpretations for the occurrence of the two classes of single-strand breaks are discussed.

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Section: Discussionmentioning

confidence: 91%

Three Classes of DNA Strand Breaks Induced by X-irradiation and Internal β-rays

Dikomey

Franzke

1986

International Journal of Radiation Biology and Related Studies

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“…4). These breaks might be of the type possessing 5'-phosphate, 3'-OH end groups which can be rejoined very quickly by polynucleotide ligase [21].…”

Section: Discussionmentioning

confidence: 99%

Complex repair kinetics of DNA strand breaks induced by γ-rays or UV radiation in Ehrlich ascites tumour cells

Mlejnek

Kozubek

1996

Radiat Environ Biophys

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Fluorometric analysis of DNA unwinding (FADU)-a sensitive technique for the detection of strand breaks in DNA-has been modified and used for the detailed investigation of repair kinetics of DNA-strand breaks arising under different conditions in Ehrlich ascites tumour (EAT) cells irradiated by gamma-rays or ultraviolet (UV) radiation. The repair kinetics of DNA-strand breaks induced in EAT cells by gamma-radiation was measured at radiation doses of 8, 20 and 50 Gy. We found complex repair curves in all cases, probably reflecting the combined processes of break rejoining and break generation during repair. In order to affect the above-mentioned processes, we have used different conditions of repair and different types of radiation. Lowering of the temperature of incubation and treating the cells by 5-fluoro-2'-deoxyuridine (FUdR) lead to complex changes of the repair curve with a reduced "wave" pattern. In order to change the type of damage to DNA, we used UV radiation (254 nm, 10 and 20 J/m2). Detailed studies of the repair kinetics showed that the repair curve for 10 J/m2 had a second maximum within 70 min after irradiation.

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“…The radiosensitive nature of thymocytes provides an attractive system to study DNA repair [26, 27]. As we are interested to look at the early kinetics of DNA repair within 1 h after irradiation, we choose mouse β -globin gene which is constitutively expressed in transcriptionally active or inactive domains thus acting as a biomarker of overall DNA repair [28, 29].…”

Section: Introductionmentioning

confidence: 99%

“…Intraperitoneal administration of REC-2006 to mice at 15 mg kg −1 body weight conferred more than 90% protection against whole-body irradiation (10 Gy) as compared to 72% offered by 34.5 mg kg −1 body weight administration of the parent plant extract RP-1. The radiosensitive nature of thymocytes provides an attractive system to study DNA repair [ 26 , 27 ]. As we are interested to look at the early kinetics of DNA repair within 1 h after irradiation, we choose mouse β -globin gene which is constitutively expressed in transcriptionally active or inactive domains thus acting as a biomarker of overall DNA repair [ 28 , 29 ].…”

Section: Introductionmentioning

confidence: 99%

REC‐2006—A Fractionated Extract of Podophyllum hexandrum Protects Cellular DNA from Radiation‐Induced Damage by Reducing the Initial Damage and Enhancing Its Repair In Vivo

Chaudhary

Shukla

Sharma

2011

Evidence-Based Complementary and Alternative Medicine

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Podophyllum hexandrum, a perennial herb commonly known as the Himalayan May Apple, is well known in Indian and Chinese traditional systems of medicine. P. hexandrum has been widely used for the treatment of venereal warts, skin infections, bacterial and viral infections, and different cancers of the brain, lung and bladder. This study aimed at elucidating the effect of REC-2006, a bioactive fractionated extract from the rhizome of P. hexandrum, on the kinetics of induction and repair of radiation-induced DNA damage in murine thymocytes in vivo. We evaluated its effect on non-specific radiation-induced DNA damage by the alkaline halo assay in terms of relative nuclear spreading factor (RNSF) and gene-specific radiation-induced DNA damage via semi-quantitative polymerase chain reaction. Whole body exposure of animals with gamma rays (10 Gy) caused a significant amount of DNA damage in thymocytes (RNSF values 17.7 ± 0.47, 12.96 ± 1.64 and 3.3 ± 0.014) and a reduction in the amplification of β-globin gene to 0, 28 and 43% at 0, 15 and 60 min, respectively. Administrating REC-2006 at a radioprotective concentration (15 mg kg−1 body weight) 1 h before irradiation resulted in time-dependent reduction of DNA damage evident as a decrease in RNSF values 6.156 ± 0.576, 1.647 ± 0.534 and 0.496 ± 0.012, and an increase in β-globin gene amplification 36, 95 and 99%, at 0, 15 and 60 min, respectively. REC-2006 scavenged radiation-induced hydroxyl radicals in a dose-dependent manner stabilized DPPH free radicals and also inhibited superoxide anions. Various polyphenols and flavonoides present in REC-2006 might contribute to scavenging of radiation-induced free radicals, thereby preventing DNA damage and stimulating its repair.

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Modification of End-groups in DNA Strand Breaks of Irradiated Thymocytes during Early Repair

Cited by 22 publications

References 2 publications

Three Classes of DNA Strand Breaks Induced by X-irradiation and Internal β-rays

Three Classes of DNA Strand Breaks Induced by X-irradiation and Internal β-rays

Complex repair kinetics of DNA strand breaks induced by γ-rays or UV radiation in Ehrlich ascites tumour cells

REC‐2006—A Fractionated Extract of Podophyllum hexandrum Protects Cellular DNA from Radiation‐Induced Damage by Reducing the Initial Damage and Enhancing Its Repair In Vivo

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