CS affects the number of myeloid progenitors in bone marrow.

Experimental and control groups of mice were kept in the hermetically closed chamber with or without CS (one cigarette per mouse), respectively, for 5 hours daily for 2 weeks. Bone marrow cells from control mice (n = 10 mice) and those exposed to CS (n = 10 mice) were plated into methylcellulose cultures in the presence of IL-3. Colonies were counted after 7 days of incubation. Data presented are from one representative experiment (mean ± SD).