Disturbed Proliferation of Erythropoietic Cells in Pernicious Anaemia

Abstract

THERE is considerable evidence that in many types of mammalian cells DNA synthesis (S) occupies only a part of the intermitotic time. In diploid cells the S period is preceded by an interval of time (G₁) when the nucleus has a 2c DNA content and is followed by a pre-mitotic interval (G₂) when the nucleus has a 4c DNA content^1,2. Conventional autoradiography of a cell population labelled briefly with tritiated thymidine can show the cells in S, but it is not possible to be certain whether an unlabelled cell is in G₁ or G₂. This difficulty can be overcome when autoradiography is combined with quantitative cytochemical measurement of the DNA content³. Furthermore, this technique can be used to examine cells the morphology of which has been identified using classical staining techniques⁴. We have used this technique in the investigation of the relation of the morphology of erythropoietic cells and their position in interphase. The distribution in normal bone marrow has been compared with that in severe pernicious anaemia to locate the site in the maturation sequence at which ineffective erythropoiesis becomes predominant.