A multi-center four-hourly sampling of many tissues for 7 days (00:00 on April 5-20:00 to April 11, 2004), on rats standardized for 1 month in two rooms on antiphasic lighting regimens happened to start on the day after the second extremum of a moderate double magnetic storm gauged by the planetary geomagnetic Kp index (which at each extremum reached 6.3 international [arbitrary] units) and by an equatorial index Dst falling to -112 and -81 nT, respectively, the latter on the first day of the sampling. Neuroendocrine chronomes (specifically circadian time structures) differed during magnetically affected and quiet days.
View Article and Find Full Text PDFBiomed Pharmacother
October 2005
Overswinging or CHAT (brief for Circadian Hyper-Amplitude-Tension), that is an excessive circadian variation in blood pressure (BP), has been associated with a large increase in cardiovascular disease risk, present even in the absence of an elevated BP itself. This usually asymptomatic condition is usually overlooked by current practice based on spot-checks, because to be diagnosed, measurements need to be taken around-the-clock, preferably for 7 days at the outset. Once diagnosed, however, a usual circadian BP pattern can be restored by means of certain non-pharmacologic or pharmacologic interventions timed appropriately.
View Article and Find Full Text PDFSome patients with hypertension exhibit disturbed circadian organization in the cardiovascular system. Hormone melatonin can synchronize circadian rhythms and its repeated administration can improve synchronization of rhythmicity in blood pressure (BP). In our study we measured endogenous melatonin production in patients with essential hypertension exhibiting a dipping and non-dipping BP profile.
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