title: Circadian rhythm of sister chromatid exchanges in human chromosomes.
abstract: Since sister chromatid exchange (SCE) relates directly to DNA synthesis which is circadian periodic, this study examines whether a circadian rhythm also characterizes SCEs. In 4-hourly blood samples collected for 48 hours on three diurnally active, nocturnally resting subjects with no family history of chromosome aberrations or instability, a circadian rhythm is demonstrable with an acrophase occurring around 14:45. The circadian amplitude is only of the order of 10% of the MESOR in untreated cultures or in cultures exposed to cefodizime. It remains more or less unchanged in cultures exposed to mitomycin-C, while the MESOR increases by about a factor of 2. In studies of human chromosome aberrations, the circadian rhythmicity of SCE should be taken into consideration.
authors.affiliation: Genetics Section, Teresa Herrera Hospital, La Coruna, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Goyanes
authors.forename: A
authors.initials: A
authors.lastname: Cupeiro
authors.forename: A
authors.initials: A
authors.lastname: Campos
authors.forename: B
authors.initials: B
authors.lastname: Lage
authors.forename: L
authors.initials: L
authors.lastname: Garcia Alonso
authors.forename: G
authors.initials: G
authors.lastname: Cornélissen
authors.forename: F
authors.initials: F
authors.lastname: Halberg
mesh_terms: D000328:Adult; D002439:Cefotaxime / Q000031:analogs & derivatives / Q000494:pharmacology; D002478:Cells, Cultured / Q000187:drug effects; D002511:Cephalosporins / Q000494:pharmacology; D002875:Chromosomes / Q000235:genetics*; D002940:Circadian Rhythm / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D016685:Mitomycin / Q000494:pharmacology; D012854:Sister Chromatid Exchange / Q000502:physiology*; D013601:T-Lymphocytes / Q000187:drug effects
chemical_list: D002511:Cephalosporins; D016685:Mitomycin; D002439:Cefotaxime; C033356:cefodizime