Amplitudes and latencies of components of visual evoked potentials (VEPs) were analysed during the 24-h cycle in humans. Circadian variations of other physiological parameters (oral temperature, urine volume and urinary potassium excretion) and of psychomotor performance (grip strength, tapping rate, visual reaction time and performance on a letter cancellation test) were also assessed. Eight male volunteers (aged 20-34 years) were tested twice over a period of 30 h. Test sessions took place every 3 h (1100 hours, 1400 hours etc.). VEPs were elicited by checkerboard pattern reversals. Significant circadian variations in the VEPs were found for the latencies of the P100 and N140 components, which were longest between 2 a.m. and 5 a.m. (P100: 103 ms; N140: 138 ms) and shortest at about 5 p.m. (P100: 97 ms; N140: 130 ms). Pronounced circadian variations were also observed in physiological parameters and in psychomotor performance measures. Circadian variation of oral temperature was correlated with the 24-h profiles of most of the other variables. Time courses of VEP latencies and oral temperature were moderately negatively correlated. However, from the data presented it seems premature to conclude that there is a common pacemaker for the circadian variations of the different parameters investigated.
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http://dx.doi.org/10.1007/BF00314180 | DOI Listing |
NPJ Biol Timing Sleep
January 2025
Section of Chronobiology, School of Biosciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH UK.
Time-of-day variation in the molecular profile of biofluids and tissues is a well-described phenomenon, but-especially for proteomics-is rarely considered in terms of the challenges this presents to reproducible biomarker identification. We provide a case study analysis of human circadian and ultradian rhythmicity in proteins, including in the complement and coagulation cascades and apolipoproteins, with PLG, CFAH, ZA2G and ITIH2 demonstrated as rhythmic for the first time. We also show that rhythmicity increases the risk of Type II errors due to the reduction in statistical power from increased variance, and that controlling for rhythmic time-of-day variation improves statistical power and reduces the chances of Type II errors.
View Article and Find Full Text PDFJ Am Heart Assoc
January 2025
Center for Coronary Artery Disease, Division of Cardiology Beijing Anzhen Hospital, Capital Medical University Beijing China.
Background: The circadian rhythm of myocardial infarction (MI) in patients with obstructive sleep apnea (OSA) remains disputable and no studies have directly evaluated the relationship between nocturnal hypoxemia and the circadian rhythm of MI. The aim of the current study was to evaluate the association of OSA and nocturnal hypoxemia with MI onset during the night.
Methods: Patients with MI in the OSA-acute coronary syndrome (ACS) project (NCT03362385) were recruited.
Handb Clin Neurol
January 2025
Department of Neurology, Medical University Innsbruck, Innsbruck, Austria.
This chapter provides an overview of circadian pattern in restless legs syndrome (RLS). Circadian variation of symptoms is a known feature of RLS. According to one of the five essential criteria for RLS diagnosis, symptoms "only occur or are worse in the evening or at night than during the day.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Division of Pharmaceutics, Faculty of Pharmaceutical Sciences, Sanyo-Onoda City University, Yamaguchi 756-0884, Japan.
The application of regenerative therapy through stem cell transplantation has emerged as a promising avenue for the treatment of diabetes mellitus (DM). Transplanted tissue homeostasis is affected by disturbances in the clock genes of stem cells. The aim of this study is to investigate the diurnal variation in mitochondrial genes and function after transplantation of adipose-derived mesenchymal stem cells (T2DM-ADSCs) from type 2 diabetic patients into immunodeficient mice.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Thrombosis and Hemostasis Unit, Rambam Health Care Campus, Haifa 3109601, Israel.
Circadian misalignment, due to shiftwork and/or individual chronotype and/or social jetlag (SJL), quantified as the difference between internal and social timing, may contribute to cardiovascular disease. Markers of endothelial dysfunction and activation of the coagulation system may predict cardiovascular pathology. The present study aim was to investigate the effects of shift work, SJL, and chronotype on endothelial function and coagulation parameters.
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