An improved plasma culture system for the production of megakaryocyte colonies in vitro.

A modified culture system has been developed to grow and quantitate megakaryocyte colonies from mouse bone marrow more efficiently than described in other reports. Using this method, it was shown that 30% of CFU-M in normal marrow cells and 70 to 90% of CFU-M in regenerating marrow cells were killed by high specific activity 3H-TdR in vitro. These results indicate that CFU-M are proliferating even in normal adult hemopoietic tissue, but that the proportion of cells that are proliferating is greater in regenerating marrow than in normal intact mice.