To the Nuclear Region Occupied by Nucleolar Bodies in Human Leukaemic Myeloblasts of Kasumi 1 and K 562 Lineages

Abstract

Previous observation demonstrated that measured nucleolar and nuclear diameters and the resulting calculated ratio might facilitate estimation of the approximate size of the nuclear region occupied by the nucleolar bodies. The size of nuclear regions occupied by nucleolar bodies decreased during the differentiation and maturation of leukaemic lymphocytes, but was constant for each differentiation or maturation stage. The present study was undertaken to provide more information on the approximate size of the nuclear regions occupied by nucleolar bodies in leukaemic granulocytic progenitors. Myeloblasts of established Kasumi 1 and K 562 cell lineages originating from human myeloid leukaemias were convenient models for such study because they represented only one and early differentiation stage of granulocytic progenitors. According to the results, the maximal and mean nucleolar body : maximal and mean nuclear diameter ratios in myeloblasts without heavy nuclear alterations were stable and not markedly influenced by the anti-leukaemic treatment or aging. Thus, the roughly estimated size of nuclear regions occupied by nucleolar bodies in these cells appeared to be similar and stable regardless of aging or anti-leukaemic treatment. In contrast, the anti-leukaemic treatment or aging in such myeloblasts induced marked reduction of the nucleolar biosynthetic activity reflected by the decreased number of nucleolar fibrillar centres.