title: Decrease of DNA synthesis in amniotic fluid cells during the middle part of S-phase revealed by differential chromosome staining after incorporation of BrdU.
abstract: The time sequence of DNA replication in partially synchronized human amniotic fluid cells has been analysed, employing BrdU incorporation techniques.--Regardless of the interval between removal of the methotrexate/uridine block and addition of BrdU during S-phase, the treatment results in an R-type replication pattern. Conversely, replacement of BrdU containing medium by another one with thymidine yields G-type replication patterns. A thymidine pulse during the first 4 h of S-phase results in R-type replication patterns; from 7--10 h after block removal it produces G-type pattern. In between, only faint red staining dots can be found indicating a marked decrease of replicational activity during the middle part of the S-phase.
mesh_terms: D000653:Amniotic Fluid / Q000166:cytology; D001973:Bromodeoxyuridine / Q000378:metabolism; D002453:Cell Cycle; D002478:Cells, Cultured; D002875:Chromosomes / Q000032:analysis / Q000378:metabolism*; D004247:DNA / Q000096:biosynthesis*; D006801:Humans; D007399:Interphase; D008677:Metaphase; D013194:Staining and Labeling
chemical_list: D004247:DNA; D001973:Bromodeoxyuridine