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Author Cajochen, C.; Jud, C.; Munch, M.; Kobialka, S.; Wirz-Justice, A.; Albrecht, U. url  doi
openurl 
  Title Evening exposure to blue light stimulates the expression of the clock gene PER2 in humans Type Journal Article
  Year 2006 Publication The European Journal of Neuroscience Abbreviated Journal Eur J Neurosci  
  Volume 23 Issue 4 Pages 1082-1086  
  Keywords Human Health; Adult; Color; Darkness; Dose-Response Relationship, Radiation; Female; Gene Expression/*radiation effects; Humans; *Light; Male; Melatonin/metabolism; Mucous Membrane/metabolism/radiation effects; Nuclear Proteins/genetics/*metabolism; Period Circadian Proteins; Transcription Factors/genetics/*metabolism  
  Abstract (down) We developed a non-invasive method to measure and quantify human circadian PER2 gene expression in oral mucosa samples and show that this gene oscillates in a circadian (= about a day) fashion. We also have the first evidence that induction of human PER2 expression is stimulated by exposing subjects to 2 h of light in the evening. This increase in PER2 expression was statistically significant in comparison to a non-light control condition only after light at 460 nm (blue) but not after light exposure at 550 nm (green). Our results indicate that the non-image-forming visual system is involved in human circadian gene expression. The demonstration of a functional circadian machinery in human buccal samples and its response to light opens the door for investigation of human circadian rhythms at the gene level and their associated disorders.  
  Address Centre for Chronobiology, Psychiatric University Clinics, University of Basel, CH-4025 Basel, Switzerland. christian.cajochen@unibas.ch  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0953-816X ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16519674 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 727  
Permanent link to this record
 

 
Author Kujanik, S.; Mikulecky, M. url  doi
openurl 
  Title Circadian and ultradian extrasystole rhythms in healthy individuals at elevated versus lowland altitudes Type Journal Article
  Year 2010 Publication International Journal of Biometeorology Abbreviated Journal Int J Biometeorol  
  Volume 54 Issue 5 Pages 531-538  
  Keywords Human Health; Acclimatization/physiology; Aged; *Altitude; Anoxia/etiology; Cardiac Complexes, Premature/*physiopathology; Circadian Rhythm/*physiology; Electrocardiography, Ambulatory; Heart Rate/*physiology; Humans; Male; Middle Aged; Reference Values; Time Factors  
  Abstract (down) We defined chronobiologic norms for supraventricular and ventricular single extrasystoles (SV and VE, respectively) in healthy older males in lowland areas. The study was extended to higher altitudes, where hypobaric hypoxia was expected to increase extrasystole frequency, while perhaps not changing rhythmicity. In healthy men (lowland n = 37, altitude n = 22), aged 49-72 years, mean numbers of SVs and VEs were counted over a 24-h period. Cosinor regression was used to test the 24-h rhythm and its 2nd-10th harmonics. The resulting approximating function for either extrasystole type includes its point, 95% confidence interval of the mean, and 95% tolerance for single measurement estimates. Separate hourly differences (delta) between altitude and lowland (n = 59) were also analysed. Hourly means were significantly higher in the mountains versus lowland, by +0.8 beats/h on average for SVs, and by +0.9 beats/h for VEs. A relatively rich chronogram for VEs in mountains versus lowland exists. Delta VEs clearly display a 24-h component and its 2nd, 3rd, 4th and 7th harmonics. This results in significantly higher accumulation of VEs around 8.00 a.m., 11.00 a.m. and 3.00 p.m. in the mountains. The increase in extrasystole occurrence in the mountains is probably caused by higher hypobaric hypoxia and resulting sympathetic drive. Healthy men at elevated altitudes show circadian and several ultradian rhythms of single VEs dependent on the hypoxia level. This new methodological approach--evaluating the differences between two locations using delta values--promises to provide deeper insight into the occurrence of premature beats.  
  Address Dept of Physiology, Faculty of Medicine, Pavol Jozef Safarik University, Trieda SNP 1, 040 66 Kosice, Slovak Republic. stefan.kujanik@upjs.sk  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0020-7128 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:20195873 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 774  
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Author Rahman, S.A.; St Hilaire, M.A.; Lockley, S.W. url  doi
openurl 
  Title The effects of spectral tuning of evening ambient light on melatonin suppression, alertness and sleep Type Journal Article
  Year 2017 Publication Physiology & Behavior Abbreviated Journal Physiol Behav  
  Volume 177 Issue Pages 221-229  
  Keywords Human Health  
  Abstract (down) We compared the effects of bedroom-intensity light from a standard fluorescent and a blue- (i.e., short-wavelength) depleted LED source on melatonin suppression, alertness, and sleep. Sixteen healthy participants (8 females) completed a 4-day inpatient study. Participants were exposed to blue-depleted circadian-sensitive (C-LED) light and a standard fluorescent light (FL, 4100K) of equal illuminance (50lx) for 8h prior to a fixed bedtime on two separate days in a within-subject, randomized, cross-over design. Each light exposure day was preceded by a dim light (<3lx) control at the same time 24h earlier. Compared to the FL condition, control-adjusted melatonin suppression was significantly reduced. Although subjective sleepiness was not different between the two light conditions, auditory reaction times were significantly slower under C-LED conditions compared to FL 30min prior to bedtime. EEG-based correlates of alertness corroborated the reduced alertness under C-LED conditions as shown by significantly increased EEG spectral power in the delta-theta (0.5-8.0Hz) bands under C-LED as compared to FL exposure. There was no significant difference in total sleep time (TST), sleep efficiency (SE%), and slow-wave activity (SWA) between the two conditions. Unlike melatonin suppression and alertness, a significant order effect was observed on all three sleep variables, however. Individuals who received C-LED first and then FL had increased TST, SE% and SWA averaged across both nights compared to individuals who received FL first and then C-LED. These data show that the spectral characteristics of light can be fine-tuned to attenuate non-visual responses to light in humans.  
  Address Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, United States; Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115, United States; Division of Sleep and Circadian Disorders, Department of Neurology, Brigham and Women's Hospital, Boston, MA 02115, United States  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9384 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:28472667 Approved no  
  Call Number LoNNe @ kyba @ Serial 1659  
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Author Hanifin, J.P.; Lockley, S.W.; Cecil, K.; West, K.; Jablonski, M.; Warfield, B.; James, M.; Ayers, M.; Byrne, B.; Gerner, E.; Pineda, C.; Rollag, M.; Brainard, G.C. url  doi
openurl 
  Title Randomized trial of polychromatic blue-enriched light for circadian phase shifting, melatonin suppression, and alerting responses Type Journal Article
  Year 2018 Publication Physiology & Behavior Abbreviated Journal Physiol Behav  
  Volume in press Issue Pages  
  Keywords Human Health  
  Abstract (down) Wavelength comparisons have indicated that circadian phase-shifting and enhancement of subjective and EEG-correlates of alertness have a higher sensitivity to short wavelength visible light. The aim of the current study was to test whether polychromatic light enriched in the blue portion of the spectrum (17,000K) has increased efficacy for melatonin suppression, circadian phase-shifting, and alertness as compared to an equal photon density exposure to a standard white polychromatic light (4000K). Twenty healthy participants were studied in a time-free environment for 7days. The protocol included two baseline days followed by a 26-h constant routine (CR1) to assess initial circadian phase. Following CR1, participants were exposed to a full-field fluorescent light (1x10(14) photons/cm(2)/s, 4000K or 17,000K, n=10/condition) for 6.5h during the biological night. Following an 8h recovery sleep, a second 30-h CR was performed. Melatonin suppression was assessed from the difference during the light exposure and the corresponding clock time 24h earlier during CR1. Phase-shifts were calculated from the clock time difference in dim light melatonin onset time (DLMO) between CR1 and CR2. Blue-enriched light caused significantly greater suppression of melatonin than standard light ((mean+/-SD) 70.9+/-19.6% and 42.8+/-29.1%, respectively, p<0.05). There was no significant difference in the magnitude of phase delay shifts. Blue-enriched light significantly improved subjective alertness (p<0.05) but no differences were found for objective alertness. These data contribute to the optimization of the short wavelength-enriched spectra and intensities needed for circadian, neuroendocrine and neurobehavioral regulation.  
  Address Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, USA  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 0031-9384 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:30296404 Approved no  
  Call Number GFZ @ kyba @ Serial 2025  
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Author Wahl, S.; Engelhardt, M.; Schaupp, P.; Lappe, C.; Ivanov, I.V. url  doi
openurl 
  Title The inner clock – blue light sets the human rhythm Type Journal Article
  Year 2019 Publication Journal of Biophotonics Abbreviated Journal J Biophotonics  
  Volume 12 Issue 12 Pages e201900102  
  Keywords Human Health; blue light; circadian rhythm; melanopsin; melatonin; visible light  
  Abstract (down) Visible light synchronizes the human biological clock in the suprachiasmatic nuclei of the hypothalamus to the solar 24-hour cycle. Short wavelengths, perceived as blue color, are the strongest synchronizing agent for the circadian system that keeps most biological and psychological rhythms internally synchronized. Circadian rhythm is important for optimum function of organisms and circadian sleep-wake disruptions or chronic misalignment often may lead to psychiatric and neurodegenerative illness. The beneficial effect on circadian synchronization, sleep quality, mood, and cognitive performance depends not only on the light spectral composition but also on the timing of exposure and its intensity. Exposure to blue light during the day is important to suppress melatonin secretion, the hormone that is produced by the pineal gland and plays crucial role in circadian rhythm entrainment. While the exposure to blue is important for keeping organism's wellbeing, alertness, and cognitive performance during the day, chronic exposure to low-intensity blue light directly before bed-time, may have serious implications on sleep quality, circadian phase and cycle durations. This rises inevitably the need for solutions to improve wellbeing, alertness and cognitive performance in today's modern society where exposure to blue light emitting devices is ever increasing. This article is protected by copyright. All rights reserved.  
  Address Carl Zeiss Vision International GmbH, Aalen, Germany  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1864-063X ISBN Medium  
  Area Expedition Conference  
  Notes PMID:31433569 Approved no  
  Call Number GFZ @ kyba @ Serial 2655  
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