“…Myelokaryocytes were cultured in the medium containing 80% DMEM medium, 20% FBS, 280 mg/liter L-glutamine, and 50 mg/liter gentamicin (Sigma) at 37 o C, 5% CO 2 , and absolute humidity for 7 days [10,12]. Proliferative activity of CFU-F was studied by the method of cellular self-destruction with hydroxyurea (Sigma) after 24-h preincubation of myelokaryocytes with inhibitors [2,10]. The pool of S-phase CFU-F was determined as follows: N=[(a-b)/a]×100%, where is the average number of CFU-F grown from hydroxyurea-untreated cells; and b is the average number of precursors grown from hydroxyurea-treated cells.…”