[Application of sedimentation at 1 g on a Ficoll gradient to the separation of bone marrow cells].

Sedimentation at unit gravity of human bone marrow, during 15 hours at 4 degrees C on a linear density gradient of Ficoll in culture medium ranging from 1.020 to 1.065 g/ml shows that it exists a differential migration of bone marrow cells subpopulation with a precise mean densities : we find successively : 1.021 +/- 1.10(-3) g/ml for the lymphocytes, 1.024 +/- 2.5.10(-3) g/ml for the non eosinophil granulocytes, 1.025 +/- 2.5.10(-3) g/ml for the metamyelocytes, 1.030 +/- 3.5.10(-3) g/ml for the immature myeloid cells (myeloblasts, promyelocytes, myelocytes), 1.040 +/- 3.10(-3) g/ml for the eosinophil granulocytes, 1.055 +/- 10.10(-3) g/l for the megakaryocytes. The highest percentages of S phase cells, G2 and M phase cells determinated with a cytofluorograph correspond to peaks of immature myeloid cells (myeloblasts, promyelocytes and myelocytes). This method of bone marrow cells separation may be used to study the cell cycle in pathological bone marrows (leukaemia in particular) and to determine the effects and the efficiency of some antimitotics.