Tsuboi K, Yang T C, Chen D J
Life Sciences Division, Los Alamos National Laboratory, New Mexico 87545.
Radiat Res. 1992 Feb;129(2):171-6.
Cytotoxic and mutagenic effects of high-LET charged iron (56Fe) particles were measured quantitatively using primary cultures of human skin fibroblasts. Argon and lanthanum particles and gamma rays were used in comparative studies. The span of LETs selected was from 150 keV/microns (330 MeV/u) to 920 keV/microns (600 MeV/u). Mutations were scored at the hypoxanthine guanine phosphoribosyl transferase (HPRT) locus using 6-thio-guanine (6-TG) for selection. Exposure to these high-LET charged particles resulted in exponential survival curves. Mutation induction, however, was fitted by the linear model. The relative biological effectiveness (RBE) for cell killing ranged from 3.7 to 1.3, while that for mutation induction ranged from 5.7 to 0.5. Both the RBE for cell killing and the RBE for mutagenesis decreased with increasing LET over the range of 1.50 to 920 keV/microns. The inactivation cross section (sigma i) and the action cross section for mutation induction (sigma m) ranged from 32.9 to 92.0 microns2 and 1.45 to 5.56 X 10(-3) microns2; the maximum values were obtained by 56Fe with an LET of 200 keV/microns. The mutagenicity (sigma m/sigma i) ranged from 2.05 to 7.99 X 10(-5) with an inverse relationship to LET.
使用人皮肤成纤维细胞原代培养物定量测量了高传能线密度（LET）带电铁（56Fe）粒子的细胞毒性和致突变性。在比较研究中使用了氩粒子、镧粒子和γ射线。所选LET范围为150 keV/微米（330 MeV/u）至920 keV/微米（600 MeV/u）。使用6-硫鸟嘌呤（6-TG）进行选择，在次黄嘌呤鸟嘌呤磷酸核糖基转移酶（HPRT）位点对突变进行评分。暴露于这些高LET带电粒子会产生指数存活曲线。然而，突变诱导符合线性模型。细胞杀伤的相对生物效能（RBE）范围为3.7至1.3，而突变诱导的RBE范围为5.7至0.5。在150至920 keV/微米的范围内，随着LET增加，细胞杀伤的RBE和诱变的RBE均降低。失活截面（σi）和突变诱导作用截面（σm）范围分别为32.9至92.0微米²和1.45至5.56×10⁻³微米²；LET为200 keV/微米的56Fe获得了最大值。诱变性（σm/σi）范围为2.05至7.99×10⁻⁵，与LET呈反比关系。
