−VPA | +VPA (1 mM) | Ratio | p | |
---|---|---|---|---|
Cell number | ||||
Day 0 | 1 | 1 | 100% | |
Day 1.5 | 5.8 ± 0.5 | 3.8 ± 0.5 | 66% | <0.001 |
Day 3 | 34.4 ± 2.8 | 15.6 ± 1.9 | 45% | <0.001 |
[3H]Thymidine incorporation | 1041 ± 8 | 538 ± 49 | 52% | <0.001 |
Cells were counted in a hemocytometer and values are presented relative to the number at day 0. Values are mean ± S.D. from a total of six determinations in two independent experiments with triplicate cultures each. The ratio of VPA versus nontreated cultures is given. Significance of difference between control and VPA-treated cultures was tested by Student's t test. Thymidine incorporation (cpm) was determined by addition of 1 μCi of [3H]thymidine per culture well for 12 h after 10,000 cells had been cultured for 1.5 days in the absence or presence of VPA on a microtiter culture dish. Values represent the relative recovery of insoluble radioactivity as mean ± S.D. from quadruple determinations. Similar results were obtained in three independent experiments.