Genetic damage induced by in vitro irradiation of human G0 lymphocytes with low-energy protons (28 keV/microm): HPRT mutations and chromosome aberrations.
Cell survival, mutations and chromosomal effects were studied in primary human lymphocytes exposed in G0 phase to a proton beam with an incident energy of 0.88 MeV (incident LET of 28 keV/microm) in the dose range 0.125-2 Gy. The curves for survival and mutations at the hypoxanthine-guanine phosphoribosyl transferase locus were obtained by fitting the experimental data to linear and linear-quadratic equations, respectively. In the dose interval 0-1.5 Gy, the alpha parameters of the curves were 0.42/Gy and 3.6 x 10(-6) mutants/Gy, respectively. The mutation types at the HPRT locus were analyzed by multiplex-PCR in 94 irradiated and 41 nonirradiated clones derived from T lymphocytes from five healthy donors. All clones showed a normal multiplex-PCR pattern and were classified as point mutations. Chromosome aberration data were fitted as a linear function of dose (alpha = 0.62 aberrations per cell Gy(-1)). By irradiating G0 lymphocytes from a single subject with 28 keV/microm protons and gamma rays, an RBE of 6.07 was obtained for chromosome aberrations. An overinvolvement of chromosome 9 relative to chromosome 7 was found in chromosome breaks after chromosome painting analysis.
Mognato
Maddalena
M
Dipartimento di Biologia, via U. Bassi 58 B, 35121 Padova, Italy.
Bortoletto
Elisabetta
E
Ferraro
Paola
P
Baggio
Laura
L
Cherubini
Roberto
R
Canova
Sabrina
S
Russo
Antonella
A
Celotti
Lucia
L
D002470:Cell Survival; D002869:Chromosome Aberrations; D020223:Chromosome Painting; D004307:Dose-Response Relationship, Radiation; D015321:Gene Rearrangement; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D008214:Lymphocytes / Q000528:radiation effects*; D009154:Mutation; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D011522:Protons; D011948:Receptors, Antigen, T-Cell / Q000235:genetics; D016192:Resting Phase, Cell Cycle / Q000528:radiation effects*; D013601:T-Lymphocytes / Q000528:radiation effects
D011522:Protons; D011948:Receptors, Antigen, T-Cell; D007041:Hypoxanthine Phosphoribosyltransferase