Quantitative studies on the arrangement of human metaphase chromosomes. V. The association pattern of acrocentric chromosomes in human meningiomas after the loss of G and D chromosomes.
The association pattern was studied in 2715 mitoses of 90 meningiomas with different numbers of acrocentric chromosomes. In cells with monosomy 22, a significant increase of mitoses with associations was observed in comparison to cells with a normal karyotype. The number of associating acrocentric chromosomes was highly significantly increased. This surplus was not only caused by a highly significant increase of associating G chromosomes but also of D chromosomes. The loss of further acrocentric chromosomes had no significant influence on the number of mitoses with associations or the number of associating chromosomes. Based on the well-known correlations between the nucleolus organization and the association pattern, the results seem to indicate a compensation mechanism among the nucleoles organizing regions (NOR's) which keeps the supply of nucleolar material constant and simultaneously causes a higher association tendency between the remaining acrocentric chromosomes. The increase of associations in the 22 monosomic cells was interpreted as a overcompensation after the loss of only one NOR.
D002453:Cell Cycle; D002466:Cell Nucleolus; D002877:Chromosomes, Human; D002901:Chromosomes, Human, 13-15; D002904:Chromosomes, Human, 21-22 and Y; D006801:Humans; D008577:Meningeal Neoplasms / Q000648:ultrastructure*; D008579:Meningioma / Q000648:ultrastructure*; D008677:Metaphase