砷对人血淋巴细胞转化及DNA合成的效应

EFFECTS OF ARSENIC ON BLAST TRANSFORMATION AND DNA SYNTHESIS OF HUMAN BLOOD LYMPHOCYTES

无机砷化合物（亚砷酸钠和砷酸钠）对未致敏人血淋巴细胞的转化和ＤＮＡ合成是双相性的，即在低浓度下可促进淋巴细胞转化，而在较高浓度下抑制淋巴细胞的转化。人血淋巴细胞具有自发的ＤＮＡ合成作用，低浓度的砷对这种自发ＤＮＡ合成有促进作用，高浓度砷则有抑制作用。人血淋巴细胞与砷连续接触３天以后，其转化过程便被诱发；连续接触砷６天以后，转化过程受砷的刺激达到最大；细胞与砷接触时间愈长，具最大刺激效应的砷浓度就愈低。三价砷较五价砷的效应强。Ｐ＜０．０１；＊Ｐ＜０．００１。表２砷酸钠对人血淋巴细胞转化的效应ｔ检验结果，与对照组相比：＊Ｐ＜０．０５；Ｐ＜０．０１；＊Ｐ＜０．００１。其刺激效应在第３天即达到最大。抗原对淋巴细胞转化的诱导所需时间也较长，一般需６天，作用也较弱。因此，砷对人血淋巴细胞转化的诱导作用，在作用时间和方式上与抗原的作用相似。但是，砷的作用与抗原又有不同，抗原需预先对个体致敏，是特异的；而砷的效应不是特异的，不需要预先致敏。２．１．３实验结果也表明，人血淋巴细胞存在自发的淋巴细胞转比过程，未受砷刺激的对照组淋巴细胞在体外培养６天后，其ＤＮＡ合成速率远高于在体外培养３天者（见表１、２）。２．２砷对淋巴细胞ＤＮ?

Effects of inorganic arsenicals(sodium arsenite and sodium arsenate) on blast transformation and DNA synthesis of unsensitized human blood lymphocytes were biphasic:the chemicals at very low concentrations enhanced the blast transformation and DNA synthesis,whereas higher concentrations inhibited these processes.Arsenicals must be present for the entire 6day culture period to produce maximum stimulation of the blast transformation.The longer exposure of the lymphocytes to arsenicals,the lower the concentrations of arsenicals at which the maximum stimulating effect on the blast transformation was found.Stimulating effect of trivalent arsenic on the blast transformation and DNA synthesis was stronger than that of pentavalent.