Chronology and Pattern of Human Chromosome Replication. V. Blood Leukocytes of Chronic Myelocytic Leukemia

Summary

Results of autoradiographic studies performed on cultured blood cells of Ph¹-positive patients with chronic myelocytic leukemia (6 females and 2 males) indicated that: 1) phytohemagglutinin P (PHA) stimulated the incorporation of tritiated thymidine into the chromosomes of normal (diploid) blood leukocytes, possibly by shortening their G2 period; 2) PHA did not affect the incorporation pattern in Ph¹-positive leukocytes, though there were a few exceptions; 3) the Ph¹ was probably not characterized by a unique replicatory pattern, since its labeling did not differ radically from that of the autosomes of group G; 4) the chronology of the late-replicating chromosomes, particularly that of one X chromosome in female cells, was retained in the leukemic leukocytes, including those with an aneuploid mode; and 5) there may be some deviation from the chronology of chromosome replication, because some cells that had an aneuploid chromosome constitution and were Ph¹-positive showed very late replication of one autosome of group C besides the late-replicating X. In general, however, the chromosomal replicatory pattern in Ph¹-positive cells, including those with an aneuploid makeup, appeared not to differ substantially from that of the normal lymphocytes in the blood of the subjects studied.