[Changes in the type and frequency of chromosome associations in human peripheral blood lymphocytes after treatment...

Changes in the character and frequency of chromosome associations in metaphase cells of human lymphocyte cultures during colcemid treatment were studied. As the time of colcemid treatment was extended from 0 to 24 h, the number of both cells with chromosome associations and of chromosomes involved in this process was seen to increase. After a 1 h incubation of cells with colcemid the number of nucleolar-organizing chromosome associations increased considerably. In 3 h, non-nucleolar-organizing chromosomes were also involved in associations: among these most often were noticed chromosomes 1, 2 and 3, and less often chromosome 11. Following 24 h of colcemid influence, the number of telomeric associations of chromosomes increased, with most frequent involvement of chromosomes 1, 4, 6 and 16. Results of this investigation allow to propose that the step-by-step involvement of metaphase chromosomes in associations, as the time of colcemid treatment increases, may reflect the remoteness of the respective chromosomes from the nucleolus. Thus, in human blood lymphocytes chromosomes 1, 2, 3 and 11 are very likely localized near the nucleolus, or some regions of these chromosomes may contact with the nucleolus.