Prematurely condensed chromosome fragments in human lymphocytes induced by high doses of high-linear-energy-transfer irradiation.
This study provides a useful biodosimetry protocol for radiation accidents that involve high doses of heavy particle radiation. Human peripheral blood lymphocytes (PBLs) were irradiated in vitro with high doses (5-50 Gy) of charged heavy-ion particles (carbon ions, at an effective linear-energy-transfer (LET) of 34.6 keV/microm), and were then stimulated to obtain dividing cells. PBLs were treated with 100 nM calyculin A to force chromosomes to condense prematurely, and chromosome spreads were obtained and stained with Giemsa. The G2 prematurely condensed chromosome (G2-PCC) index and the number of G2-PCC including fragments (G2-PCC-Fs) per cell for each radiation dose point were scored. Dose-effect relationships were obtained by plotting the G2-PCC indices or G2-PCC-Fs numbers against radiation doses. The G2-PCC index was greater than 5% up to doses of 15 Gy; even after a 30 Gy radiation dose, the index was 1 to 2%. At doses higher than 30 Gy, however, the G2-PCC indices were close to zero. The number of G2-PCC-Fs increased steeply for radiation doses up to 30 Gy at a rate of 1.07 Gy(-1). At doses higher than 30 Gy, the numbers of G2-PCC-Fs could not be accurately indexed because of the limited numbers of cells for analysis. Therefore, the number of G2-PCC-Fs could be used to estimate radiation doses up to 30 Gy. In addition, a G2-PCC index close to zero could be used as an indicator for radiation doses greater than 40 Gy.
Wang
Z Z
ZZ
Radiobiology Laboratory, Institute of Modern Physics, Chinese Academy of Sciences, Nanchang Road No.509 Lanzhou 730000, Gansu Province, China. wangzhuanzi@sina.com
Li
W J
WJ
Zhi
D J
DJ
Gao
Q X
QX
Qu
Y
Y
Wang
B Q
BQ
D002244:Carbon; D002478:Cells, Cultured; D019457:Chromosome Breakage; D004307:Dose-Response Relationship, Radiation; D020450:Heavy Ions / Q000009:adverse effects*; D006801:Humans; D018499:Linear Energy Transfer; D008214:Lymphocytes / Q000528:radiation effects*; D011829:Radiation Dosage; D011832:Radiation Injuries; D011874:Radiometry
D002244:Carbon