Ferle-Vidović A, Petrović D, Sorić J, Slaus I, Rendić D
Int J Radiat Biol Relat Stud Phys Chem Med. 1979 Aug;36(2):117-26. doi: 10.1080/09553007914550871.
L929 cells were irradiated by cyclotron-produced neutrons and by 14.8 MeV monoenergetic neutrons. For comparison cells were also irradiated by 60Co gamma rays. Following irradiation cells were treated by an equimolar solution of deoxyribonucleosides, and the effect on cell survival measured. Results show that nucleoside treatment was efficient after low-LET irradiation: gamma ray survival curves were altered by deoxyribonucleosides in terms of significantly increased extrapolation numbers only, but without Do change. Cells irradiated by neutrons from either of the two sources did not respond to nucleoside treatment, and consequently their survival curves remained unaltered. These results show that the nucleoside effect does occur after low-LET irradiation, but apparently not following high-LET irradiation. Since deoxyribonucleosides as well as other cell breakdown products are released in irradiated and necrotic tumours due to massive cell destruction, such a nucleoside effect could possibly enhance the cell survival and thus effect the result of radiotherapy. Absence of the nucleoside effect in case of high-LET irradiation may therefore be an additional potential gain from neutrons in radiotherapy.
L929细胞受到回旋加速器产生的中子和14.8兆电子伏特单能中子的照射。作为对照，细胞也受到60Coγ射线的照射。照射后，细胞用等摩尔的脱氧核糖核苷溶液处理，并测量对细胞存活的影响。结果表明，在低传能线密度照射后，核苷处理是有效的：脱氧核糖核苷改变了γ射线存活曲线，仅在外推数上显著增加，但没有剂量存活曲线初始斜率（Do）的变化。用两种来源中的任何一种中子照射的细胞对核苷处理没有反应，因此它们的存活曲线保持不变。这些结果表明，核苷效应确实发生在低传能线密度照射后，但显然不在高传能线密度照射后发生。由于在受照射和坏死的肿瘤中，由于大量细胞破坏会释放出脱氧核糖核苷以及其他细胞分解产物，这种核苷效应可能会提高细胞存活率，从而影响放射治疗的效果。因此，在高传能线密度照射情况下不存在核苷效应，这可能是中子在放射治疗中的另一个潜在优势。
