title: [Degradation and repair of rat hepatoma cell DNA following exposure to gamma rays and methylnitrosourea].
abstract: Single-strand breaks induced in DNA of ascitic hepatoma cells by gamma-rays and N-methyl-N-nitrosourea (MNU), resp., may be effectively repaired. Double-strand breaks of DNA from MNU-treated hepatoma cells are also effectively repairable in vivo. Only a small part of double-strand breaks induced by gamma-rays in DNA of these cells is repaired in the postradiation period. The combined action of gamma-rays and MNU on the hepatoma cells causes a complete inhibition of repair of DNA and its further degradation. Under these conditions, inhibition of the repair of DNA synthesis and repression of DNA polymerase I activity is observed.
mesh_terms: D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000201:enzymology / Q000378:metabolism* / Q000532:radiotherapy; D004256:DNA Polymerase I / Q000378:metabolism; D004260:DNA Repair / Q000187:drug effects / Q000528:radiation effects; D004273:DNA, Neoplasm / Q000378:metabolism* / Q000528:radiation effects; D005720:Gamma Rays; D008113:Liver Neoplasms / Q000201:enzymology / Q000378:metabolism / Q000532:radiotherapy; D008297:Male; D008770:Methylnitrosourea / Q000494:pharmacology*; D009374:Neoplasms, Experimental; D009607:Nitrosourea Compounds / Q000494:pharmacology*; D051381:Rats
chemical_list: D004273:DNA, Neoplasm; D009607:Nitrosourea Compounds; D008770:Methylnitrosourea; D004256:DNA Polymerase I
vernacular_title: Degradatsiia i reparatsiia DNK kletok gepatomy krys posle deistviia gamma-lucheĭ i metilnitrozomocheviny.