Effects of oligonucleotides on the number of CFU-GM colonies. Bone marrow cells were obtained by gradient centrifugation and cultured in agar. Oligo buffer only (▪), antisense RB oligonucleotides (AS1; ▨), or sense orientated oligonucleotides (SO1; □) were added at indicated concentrations on days 0 and 7. Colonies (>40 cells) were scored on day 14. Values shown are the percentages of the number of colonies formed when oligo buffer only was added. Results shown represent the mean values from 3 separate experiments (bars ± SEM). The total number of colonies formed per dish with oligo buffer added was 63 ± 7 (SEM).