De Boer P, Van Buul P P, Van Beek R, Van Der Hoeven F A, Natarajan T
Mutat Res. 1977 Mar;42(3):379-94. doi: 10.1016/s0027-5107(77)80043-2.
The frequencies were studied X-ray-induced dicentric chromosomes and deletions in peripheral blood lymphocytes of mouse and man, cultured in vitro. After doses of 100 and 200 rad, (a) the mouse was equally sensitive as man to the induction of dicentrics, and (b) the frequency of deletions was higher in the mouse, reaching statistical significance at the 200 rad level only. At the 200 rad level, the mouse with normal karyotype was compared with the T(1;13)70H translocation heterozygote and the Ts(1(13))7OH tertiary trisomic of normal appearance. No differences were found either with respect to dicentrics or to deletions. At the 100 rad level, the normal mouse was compared with the tertiary trisomic mouse of the affected phenotype and with the tobacco mouse. The frequency of dicentrics was significantly higher in the phenotypically abnormal trisomics, whereas the deletion frequency was higher in the tobacco mice. C-banding of the slides enabled the locating of breaks in constitutive hetero-chromatin and euchromatin. When exchanges were classified into three categories, i.e. those between eu- and euchromatin, eu- and hetero-, and hetero- and heterochromatin, there was a preference for the first and the last whereas only few occurred between chromatins of contrasting type. Differences between previous determinations of the chromosomal radiosensitivity of mouse and man, using peripheral blood lymphocytes (i.e. man is twice as sensitive as mouse), and the one presented here could be attributed to differences in harvest time of the mouse peripheral blood lymphocytes. Thus the so-called "arm number" hypothesis of Brewen et al. [5] is not confirmed by the present results.
研究了X射线诱导的小鼠和人外周血淋巴细胞中双着丝粒染色体和缺失的频率，这些细胞是在体外培养的。在100和200拉德剂量后，(a)小鼠在诱导双着丝粒方面与人同样敏感，(b)缺失频率在小鼠中更高，仅在200拉德水平达到统计学显著差异。在200拉德水平，将核型正常的小鼠与T(1;13)70H易位杂合子以及外观正常的Ts(1(13))7OH三级三体小鼠进行比较。在双着丝粒或缺失方面均未发现差异。在100拉德水平，将正常小鼠与具有受影响表型的三级三体小鼠以及烟草小鼠进行比较。在表型异常的三体小鼠中双着丝粒频率显著更高，而在烟草小鼠中缺失频率更高。玻片的C带染色能够确定组成型异染色质和常染色质中的断裂位置。当交换被分为三类，即常染色质与常染色质之间、常染色质与异染色质之间以及异染色质与异染色质之间的交换时，更倾向于第一类和最后一类，而不同类型染色质之间的交换很少。先前使用外周血淋巴细胞测定小鼠和人染色体放射敏感性的结果（即人比小鼠敏感两倍）与本文呈现的结果之间的差异，可能归因于小鼠外周血淋巴细胞收获时间的不同。因此，Brewen等人[5]的所谓“臂数”假说未被本研究结果证实。
