In order to define the functional defect in marrow cells in B12 and folate deficiency, ten patients were investigated. Chromosome studies showed alterations similar to those produced experimentally by agents interfering with DNA metabolism. Measurements of the DNA content of individual cells in the resting and synthetic stages of the mitotic cycle suggested arrest of DNA synthesis in a proportion of cells, or alternatively prolongation of the S and G2 phases. It was concluded that in these deficiency states changes in the cellular DNA metabolism may cause disturbances during both the mitotic and intermitotic stages of the cell cycle, and that these may account for the deficient production of the various classes of blood cells.

No abstract