Year: 1976
Type: article
Abstract: A B S T R A C T Colcemid was found to induce a dose and schedule dependent marrow magakaryocytosis and peripheral thrombocytosis.The response could be divided into early and late components.The early component appears to have been due to a direct stimulatory effect, probably by enhancement of endo- reduplication in metaphase arrested megakaryocyte precursors.The early stimulatory response was blunted on toxic drug schedules.In contrast, the late com- ponent of the thrombopoietic response was demon- strated best on the most toxic drug schedules.It coincided temporally with the reactive restoration of the mononuclear marrow and blood cell elements, respectively.Thus, the late component appears to be a nonspecific rebound phenomenon.On comparing the thrombopoietic properties of Colcemid with those of the vinca alkaloids in experi- mental systems, the former appears to have a more favorable therapeutic index.The data suggest that colchicine and its derivatives may be useful agents in the treatment of clinical thrombocytopenic states.This was of particular interest, since the increase in megakaryocytes was observed at a time when the immature nucleated cells and mature granulocytes were decreasing in number.The chromosomal complement of morphologically recognizable megakaryocytes is tetraploid or greater (2, 3), and these cells are thought to increase their ploidy through one or more rounds of endoreduplica- tive DNA synthesis before cytoplasmic maturation (4-6).Presumably the earliest recognizable mega-
DOI: 10.1172/jci108583
Authors: P A Bunn, S E Shackney, S S Ford
Institutions: Office of the Director, National Cancer Institute
Language: English
Subfield: Hematology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W1969822634