title: Chronobiologic approach to beat-to-beat variations of cultured murine myocardial cells.
abstract: An earlier demonstration of a circadian rhythm in rat atria by others is complemented herein by observations in culture: A single murine myocardial cell and two sets of grouped cells beating in culture for several days reveal several features of an anticipated, presumably built-in spectrum of multifrequency rhythms and trends, the chronome. Circadian and about 12-h (circasemidian) components are modulated by an approximately 84-h (circasemiseptan) component, which cannot be separated from trends in view of the brevity of the series. The circumstance under which the culture is aging and in which fibroblasts proliferate is a further complication that limits the findings to a single cycle reproduced in three separate cultures. Whether it is a rhythm that repeats itself of a response to placement into culture, an approximately 3.5-d component in the beating of myocardial cells in culture is to be aligned with a very prominent similar component found in the incidence of 85,819 human myocardial infarctions.
authors.affiliation: Institute of Biophysics, Academia Sinica, Beijing, China.
authors.forename: H
authors.initials: H
authors.lastname: Han
authors.forename: D
authors.initials: D
authors.lastname: Shao
authors.forename: J
authors.initials: J
authors.lastname: Wu
authors.forename: G
authors.initials: G
authors.lastname: Cornélissen
authors.forename: F
authors.initials: F
authors.lastname: Halberg
mesh_terms: D000818:Animals; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D002909:Chronobiology Phenomena; D002940:Circadian Rhythm / Q000502:physiology*; D006321:Heart / Q000502:physiology; D006339:Heart Rate / Q000502:physiology*; D009206:Myocardium / Q000166:cytology*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors