Leukaemia cytogenetics / H. Jackson Woodliff.

  • Woodliff, H. Jackson.
Date:
1971
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Leukaemia cytogenetics / H. Jackson Woodliff. Source: Wellcome Collection.

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    28 LEUKAEMIA CYTOGENETICS Fig. 8.—Chromosome aberrations. (From Amaróse et al., 1967) Endoreduplication is occasionally found in peripheral blood cultures from some normal subjects but the finding of more than two in any one preparation is more commonly seen in some diseases and following exposure to various agents; the literature has been reviewed by Powsner (1966). In endomitosis there is failure of the nucleus to divide after mitosis so that a polyploid set of chromosomes is found in the cell but without the characteristic pattern of endoreduplication, the chromosomes being distributed randomly; up to 0-5 per cent of metaphases may be of this type. Morphological Variations Normal metaphase chromosomes consist of two chromatids joined at the centromere; abnormalities may be present in one or both chromatids (Fig. 8). Secondary constrictions which are attenuated areas of one or both chromatids can be found on some normal chromosomes but may be accentuated following exposure to certain drugs and chemicals (Cohen and Shaw, 1964). Chromatid gaps are pale achromatic areas whose lengths are not greater than the width of the chromatid, and isochromatid gaps are the same lesions directly opposite each other on both sister chromatids; they may be found in a small proportion of cells from normal