title: Pattern of chromosomal replication in synchronized lymphocytes. I. Evaluation and application of methotrexate block.
abstract: The BrdUrd-Hoechst 33258-Giemsa technique was employed to study patterns of chromosomal replication in human lymphocytes synchronized by Methotrexate (MTX). It is proposed that in the presence of MTX, a major portion of the cell population is blocked in an advanced stage of the S-phase and not in the G1/S border of the cell cycle. At this point, the replication of the chromosomal segments corresponding to the R-bands is terminated, and the replication of the G-bands and the inactive X-chromosomes is being initiated. The use of this method in the study of higher resolution patterns of chromosomal replications is proposed.
mesh_terms: D002453:Cell Cycle / Q000187:drug effects*; D002871:Chromosome Banding; D002877:Chromosomes, Human / Q000187:drug effects*; D003584:Cytological Techniques; D004261:DNA Replication / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008214:Lymphocytes / Q000648:ultrastructure*; D008727:Methotrexate / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D008727:Methotrexate