Enzyme action at 3' termini of ionizing radiation-induced DNA strand breaks.

Absolute cross-sections (CSs) for the interaction of low energy electrons with condensed macromolecules are essential parameters to accurately model ionizing radiation induced reactions.

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Radiation-induced DNA Strand Breaks in Deoxygenated Aqueous Solutions. The Formation of Altered Sugars as End Groups

International Journal of Radiation Biology and Related Studies in Physics Chemistry and Medicine ◽

10.1080/09553007914551391 ◽

1979 ◽

Vol 36 (6) ◽

pp. 565-576 ◽

Cited By ~ 29

Author(s):

Friedrich Beesk ◽

Miral Dizdaroglu ◽

Dietrich Schulte-Frohlinde ◽

Clemens Von Sonntag

Keyword(s):

Aqueous Solutions ◽

Dna Strand Breaks ◽

Strand Breaks ◽

End Groups ◽

Radiation Induced ◽

Dna Strand

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KGF facilitates repair of radiation-induced DNA damage in alveolar epithelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1997.272.6.l1174 ◽

1997 ◽

Vol 272 (6) ◽

pp. L1174-L1180 ◽

Cited By ~ 25

Author(s):

M. Takeoka ◽

W. F. Ward ◽

H. Pollack ◽

D. W. Kamp ◽

R. J. Panos

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Epithelial Cells ◽

Dna Polymerase ◽

Dna Polymerases ◽

Dna Strand Breaks ◽

Strand Breaks ◽

Alveolar Epithelial ◽

Radiation Induced ◽

Dna Strand

Administration of exogenous keratinocyte growth factor (KGF) prevents or attenuates several forms of oxidant-mediated lung injury. Because DNA damage in epithelial cells is a component of radiation pneumotoxicity, we determined whether KGF ameliorated DNA strand breaks in irradiated A549 cells. Cells were exposed to 137Cs gamma rays, and DNA damage was measured by alkaline unwinding and ethidium bromide fluorescence after a 30-min recovery period. Radiation induced a dose-dependent increase in DNA strand breaks. The percentage of double-stranded DNA after exposure to 30 Gy increased from 44.6 +/- 3.5% in untreated control cells to 61.6 +/- 5.0% in cells cultured with 100 ng/ml KGF for 24 h (P < 0.05). No reduction in DNA damage occurred when the cells were cultured with KGF but maintained at 0 degree C during and after irradiation. The sparing effect of KGF on radiation-induced DNA damage was blocked by aphidicolin, an inhibitor of DNA polymerases-alpha, -delta, and -epsilon and by butylphenyl dGTP, which blocks DNA polymerase-alpha strongly and polymerases-delta and -epsilon less effectively. However, dideoxythymidine triphosphate, a specific inhibitor of DNA polymerase-beta, did not abrogate the KGF effect. Thus KGF increases DNA repair capacity in irradiated pulmonary epithelial cells, an effect mediated at least in part by DNA polymerases-alpha, -delta, and -epsilon. Enhancement of DNA repair capability after cell damage may be one mechanism by which KGF is able to ameliorate oxidant-mediated alveolar epithelial injury.

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Influence of Acute Exercise on DNA Repair and PARP Activity before and after Irradiation in Lymphocytes from Trained and Untrained Individuals

International Journal of Molecular Sciences ◽

10.3390/ijms20122999 ◽

2019 ◽

Vol 20 (12) ◽

pp. 2999 ◽

Cited By ~ 5

Author(s):

Maria Moreno-Villanueva ◽

Andreas Kramer ◽

Tabea Hammes ◽

Maria Venegas-Carro ◽

Patrick Thumm ◽

...

Keyword(s):

Physical Activity ◽

Dna Damage ◽

Dna Repair ◽

Immune Cells ◽

Acute Exercise ◽

Dna Strand Breaks ◽

Strand Breaks ◽

Before And After ◽

Radiation Induced ◽

Dna Strand

Several studies indicate that acute exercise induces DNA damage, whereas regular exercise increases DNA repair kinetics. Although the molecular mechanisms are not completely understood, the induction of endogenous reactive oxygen species (ROS) during acute exhaustive exercise due to metabolic processes might be responsible for the observed DNA damage, while an adaptive increase in antioxidant capacity due to regular physical activity seems to play an important protective role. However, the protective effect of physical activity on exogenously induced DNA damage in human immune cells has been poorly investigated. We asked the question whether individuals with a high aerobic capacity would have an enhanced response to radiation-induced DNA damage. Immune cells are highly sensitive to radiation and exercise affects lymphocyte dynamics and immune function. Therefore, we measured endogenous and radiation-induced DNA strand breaks and poly (ADP-ribose) polymerase-1 (PARP1) activity in peripheral blood mononuclear cells (PBMCs) from endurance-trained (maximum rate of oxygen consumption measured during incremental exercise V’O2max > 55 mL/min/kg) and untrained (V’O2max < 45 mL/min/kg) young healthy male volunteers before and after exhaustive exercise. Our results indicate that: (i) acute exercise induces DNA strand breaks in lymphocytes only in untrained individuals, (ii) following acute exercise, trained individuals repaired radiation-induced DNA strand breaks faster than untrained individuals, and (iii) trained subjects retained a higher level of radiation-induced PARP1 activity after acute exercise. The results of the present study indicate that increased aerobic fitness can protect immune cells against radiation-induced DNA strand breaks.

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