1999 Fiscal Year Final Research Report Summary
Mutagenic effects at HPRT locus in Chinese Hamster Ovary(CHO)cells induced by epi-thermal and thermal neutrons
| Project/Area Number |
10670845
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Radiation science
|
|---|
| Research Institution | KYOTO UNIVERSITY |
|---|
Principal Investigator |
KINASHI Yuko Kyoto University Research Reactor Institute, Radiation Oncology Research Lab., Instructor, 原子炉実験所, 助手 (80252534)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SAKURAI Yoshinori Kyoto University Research Reactor Institute, Radiation Life Science, Instructor, 原子炉実験所, 助手 (20273534)
|
|---|
| Project Period (FY) |
1998 – 1999
|
| Keywords | Epithermal neutron / Thermal neutron / Boron neutron capture therapy(BNCT) / PCR / HPRT mutation / CHO cells |
|---|
| Research Abstract |
CHO cells were exposed to thermal and epithermal neutrons and the occurrence of mutations at the HPRT locus was measured. To determine mutant frequency and cell survival, cells were irradiated with thermal and epithermal neutrons under three conditions : thermal neutron mode, mixed mode with thermal and epithermal neutrons, and epithermal neutron mode. The mutagenicity was different among the three irradiation modes, with the epithermal neutron mode showing a mutation frequency about 6.3-fold that of the thermal neutron mode and about 1.7-fold that of the mixed mode. In the thermal neutron and mixed mode, boron did not increased significantly the frequency of the mutants at the same dose. Therefore, the effect of boron as in boron neutron capture therapy (BNCT) is quantitatively minimal in terms of mutation induction. Over 300 independent neutron-induced mutant clones were isolated from separate experiments. The molecular structure of HPRT mutations was determined by analysis of all nine exons by multiplex polymerase chain reaction. In the thermal neutron and mixed modes, total and partial deletions were dominant and the fraction of total deletions were increased in the presence of boron. In the epithermal neutron mode, more than half of the mutations observed were total deletions. Our results suggest that there are clear differences between thermal and epithermal neutron beams in their mutagenicity and in the structural pattern of the mutants that they induce.
|
