Krishan A, Paika D, Frei E
Cancer Res. 1976 Jan;36(1):138-42.
2,3-Dihydro-1H-imidazo[1,2-b]pyrazole (IMPY), a DNA synthesis-inhibitory drug, reversibly arrests growth of human lymphoblasts in vitro. DNA distribution histograms of cultures exposed to 0.5 to 2.0 mM IMPY show accumulation of cells with G1-early S DNA content. On reincubation in fresh medium, cell cycle traverse is resumed by the blocked cells in a synchronized manner. Maximum incorporation of [H3]thymidine into DNA (174 to 220% of control) and labeling indexes (72 to 86%) are seen after 4 hr of incubation, and a major increase in cell number is seen between the 9th and 13th hr. DNA distribution histograms of cells reincubated in fresh medium (after double block), show an initial increase in the number od cells with S-G2-M DNA content and a corresponding decrease in the number of G1-early S cells. After 4 hr of reincubation, a gradual increase in the number of G1-early S cells was seen as the earlier blocked cells completed cell cycle traverse and mitosis. Cells exposed to 2.0 mM IMPY took approximately 2 hr longer to traverse than did cells exposed to 0.5 mM IMPY.
2,3-二氢-1H-咪唑并[1,2-b]吡唑（IMPY）是一种DNA合成抑制药物，可在体外可逆地阻止人淋巴母细胞的生长。暴露于0.5至2.0 mM IMPY的培养物的DNA分布直方图显示，具有G1期早期S期DNA含量的细胞积累。在新鲜培养基中再培养时，受阻细胞以同步方式恢复细胞周期进程。在培养4小时后，观察到[H3]胸苷掺入DNA的量达到最大值（对照组的174%至220%）和标记指数（72%至86%），并且在第9至13小时之间细胞数量有显著增加。在新鲜培养基中再培养的细胞（双重阻断后）的DNA分布直方图显示，具有S-G2-M期DNA含量的细胞数量最初增加，而G1期早期S期细胞数量相应减少。再培养4小时后，随着较早受阻的细胞完成细胞周期进程和有丝分裂，G1期早期S期细胞数量逐渐增加。暴露于2.0 mM IMPY的细胞比暴露于0.5 mM IMPY的细胞完成细胞周期进程大约多需要2小时。
