title: [Effects of damage and post-radiation reparation of cornea epithelium cells chromosomal apparatus in mice following irradiation by protons with the energy of 25 MeV].
abstract: Damage and post-radiation reparation processes were studied in cornea epithelium cells of mice irradiated by protons with the energy of 25 MeV and 60Co gamma-rays singly and in 2 fractions. Protons linear energy transfer (LET) was equal to 2.1 keV/microm, dose rate - 0.5 cGy/s. Animals were irradiated singly by 25 and 750 cGy and doubly (25 + 25; 50 + 50; 125 + 125; 250 + 250 cGy) with a 24-hr interval. Investigations were performed in 24, 72 and 120 hrs. after single and in 24 hrs. after double irradiation. Preparations were analyzed with the anaphase technique. 25 MeV protons were shown to cause more severe damages to the chromosomal apparatus in mammal cells including dramatic suppression of cell division and profuse formation of cells with aberrant mitoses as compared with gamma-induced damages. Exchange-type aberrations were more frequent. There was a reliable decrease of the aberrant mitosis rate in consequence of fractionated irradiation by 25 MeV protons and gamma-rays. On passing 24, 72 and 120 hours, coefficients of relative biological effectiveness (RBE) of 25 MeV protons were equal to 1.4 +/- 0.2; 1.3 +/- 0.1; 1.2 +/- 0.1 for the mitotic index and 1.5 +/- 0.1; 1.3 +/- 0.2; 1.1 +/- 0.1 for aberrant mitosis, respectively.
mesh_terms: D000818:Animals; D002869:Chromosome Aberrations / Q000528:radiation effects*; D019573:Epithelium, Corneal / Q000473:pathology / Q000528:radiation effects*; D005720:Gamma Rays / Q000009:adverse effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D008938:Mitosis / Q000528:radiation effects*; D011522:Protons / Q000009:adverse effects; D011829:Radiation Dosage; D013997:Time Factors
chemical_list: D011522:Protons