[Spontaneous DNA damage and DNA polynucleotide ligase activity in thymocyte populations differing in radiosensitivity].
Single-strand breaks (SB) in DNA of irradiated thymocytes are first repaired, at a half-recovery period of a few minutes, then the number of breaks rapidly increases indicating that in addition to chromatin endonucleolysis there is an imbalance between the repair enzymes that generate DNA breaks and eliminate them. The rate of SB accumulation in thymocyte fractions, upon incubation of the cells with 1-beta-D-arabinofuranosyl cytosine (AraC) and hydroxyurea (HU), is directly proportional to their radiosensitivity, whereas DNA ligase activity is higher in a fraction of highly radioresistant thymocytes. Chemical compounds that increase the survival rate of irradiated thymocytes decelerate SB accumulation in DNA and sensitivity of cells to AraC and HU. Ineffective substances have no such an effect.
T M
TM
Alferova
V A
VA
Tronov
V A
VA
Soldatenkov
M F
MF
Denisenko
I V
IV
Filippovich
D000818:Animals; D003561:Cytarabine / Q000494:pharmacology; D004249:DNA Damage; D011088:DNA Ligases / Q000528:radiation effects*; D004260:DNA Repair / Q000187:drug effects / Q000528:radiation effects; D004277:DNA, Single-Stranded / Q000187:drug effects / Q000528:radiation effects*; D005720:Gamma Rays; D006918:Hydroxyurea / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D011118:Polynucleotide Ligases / Q000528:radiation effects*; D011836:Radiation Tolerance; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects*
D004277:DNA, Single-Stranded; D003561:Cytarabine; D011088:DNA Ligases; D011118:Polynucleotide Ligases; D006918:Hydroxyurea
Spontannye povrezhdeniia DNK i aktivnost' DNK-polinukleotidligaz v populiatsiiakh timotsitov, razlichaiushchikhsia po radiochuvstvitel'nosti.