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Author Kantermann, T.
Title Circadian biology: sleep-styles shaped by light-styles Type Journal Article
Year 2013 Publication Current Biology : CB Abbreviated Journal Curr Biol
Volume (down) 23 Issue 16 Pages R689-90
Keywords Human Health; Circadian Clocks/*radiation effects; Female; Humans; *Lighting; Male; *Photoperiod; *Sunlight
Abstract Light and darkness are the main time cues synchronising all biological clocks to the external environment. This little understood evolutionary phenomenon is called circadian entrainment. A new study illuminates our understanding of how modern light- and lifestyles compromise circadian entrainment and impact our biological clocks.
Address Chronobiology – Centre for Behaviour and Neurosciences, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands. thomas@kantermann.de
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0960-9822 ISBN Medium
Area Expedition Conference
Notes PMID:23968925 Approved no
Call Number LoNNe @ christopher.kyba @ Serial 501
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Author Wright, K.P.J.; McHill, A.W.; Birks, B.R.; Griffin, B.R.; Rusterholz, T.; Chinoy, E.D.
Title Entrainment of the human circadian clock to the natural light-dark cycle Type Journal Article
Year 2013 Publication Current Biology : CB Abbreviated Journal Curr Biol
Volume (down) 23 Issue 16 Pages 1554-1558
Keywords Human Health; Adult; Circadian Clocks/*radiation effects; Female; Humans; *Lighting; Male; *Photoperiod; *Sunlight; Young Adult; Circadian Rhythm
Abstract The electric light is one of the most important human inventions. Sleep and other daily rhythms in physiology and behavior, however, evolved in the natural light-dark cycle [1], and electrical lighting is thought to have disrupted these rhythms. Yet how much the age of electrical lighting has altered the human circadian clock is unknown. Here we show that electrical lighting and the constructed environment is associated with reduced exposure to sunlight during the day, increased light exposure after sunset, and a delayed timing of the circadian clock as compared to a summer natural 14 hr 40 min:9 hr 20 min light-dark cycle camping. Furthermore, we find that after exposure to only natural light, the internal circadian clock synchronizes to solar time such that the beginning of the internal biological night occurs at sunset and the end of the internal biological night occurs before wake time just after sunrise. In addition, we find that later chronotypes show larger circadian advances when exposed to only natural light, making the timing of their internal clocks in relation to the light-dark cycle more similar to earlier chronotypes. These findings have important implications for understanding how modern light exposure patterns contribute to late sleep schedules and may disrupt sleep and circadian clocks.
Address Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309-0354, USA. kenneth.wright@colorado.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0960-9822 ISBN Medium
Area Expedition Conference
Notes PMID:23910656; PMCID:PMC4020279 Approved no
Call Number LoNNe @ christopher.kyba @ Serial 505
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Author Brainard, G.C.; Sliney, D.; Hanifin, J.P.; Glickman, G.; Byrne, B.; Greeson, J.M.; Jasser, S.; Gerner, E.; Rollag, M.D.
Title Sensitivity of the human circadian system to short-wavelength (420-nm) light Type Journal Article
Year 2008 Publication Journal of Biological Rhythms Abbreviated Journal J Biol Rhythms
Volume (down) 23 Issue 5 Pages 379-386
Keywords Human Health; Adult; Circadian Rhythm/*radiation effects; Female; Humans; *Light; Male; Melatonin/metabolism; Models, Biological; Neurosecretory Systems; Photons; Pineal Gland/metabolism; Retinal Ganglion Cells/*metabolism; Vision, Ocular
Abstract The circadian and neurobehavioral effects of light are primarily mediated by a retinal ganglion cell photoreceptor in the mammalian eye containing the photopigment melanopsin. Nine action spectrum studies using rodents, monkeys, and humans for these responses indicate peak sensitivities in the blue region of the visible spectrum ranging from 459 to 484 nm, with some disagreement in short-wavelength sensitivity of the spectrum. The aim of this work was to quantify the sensitivity of human volunteers to monochromatic 420-nm light for plasma melatonin suppression. Adult female (n=14) and male (n=12) subjects participated in 2 studies, each employing a within-subjects design. In a fluence-response study, subjects (n=8) were tested with 8 light irradiances at 420 nm ranging over a 4-log unit photon density range of 10(10) to 10(14) photons/cm(2)/sec and 1 dark exposure control night. In the other study, subjects (n=18) completed an experiment comparing melatonin suppression with equal photon doses (1.21 x 10(13) photons/cm(2)/sec) of 420 nm and 460 nm monochromatic light and a dark exposure control night. The first study demonstrated a clear fluence-response relationship between 420-nm light and melatonin suppression (p<0.001) with a half-saturation constant of 2.74 x 10(11) photons/cm(2)/sec. The second study showed that 460-nm light is significantly stronger than 420-nm light for suppressing melatonin (p<0.04). Together, the results clarify the visible short-wavelength sensitivity of the human melatonin suppression action spectrum. This basic physiological finding may be useful for optimizing lighting for therapeutic and other applications.
Address Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, USA. george.brainard@jefferson.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0748-7304 ISBN Medium
Area Expedition Conference
Notes PMID:18838601 Approved no
Call Number LoNNe @ kagoburian @ Serial 724
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Author Cajochen, C.; Jud, C.; Munch, M.; Kobialka, S.; Wirz-Justice, A.; Albrecht, U.
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 (down) 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 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
Publisher Place of Publication Editor
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
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Author Peplonska, B.; Bukowska, A.; Sobala, W.; Reszka, E.; Gromadzinska, J.; Wasowicz, W.; Lie, J.A.; Kjuus, H.; Ursin, G.
Title Rotating night shift work and mammographic density Type Journal Article
Year 2012 Publication Cancer Epidemiology, Biomarkers & Prevention : a Publication of the American Association for Cancer Research, Cosponsored by the American Society of Preventive Oncology Abbreviated Journal Cancer Epidemiol Biomarkers Prev
Volume (down) 21 Issue 7 Pages 1028-1037
Keywords Adult; Breast/*pathology; Breast Neoplasms/*etiology/*pathology; Circadian Rhythm/*physiology; Cross-Sectional Studies; Female; Humans; Melatonin/urine; Middle Aged; *Midwifery; *Nursing Staff; Questionnaires; Risk Factors; *Work Schedule Tolerance; oncogenesis
Abstract BACKGROUND: An increased risk of breast cancer has been observed in night shift workers. Exposure to artificial light at night and disruption of the endogenous circadian rhythm with suppression of the melatonin synthesis have been suggested mechanisms. We investigated the hypothesis that rotating night shift work is associated with mammographic density. METHODS: We conducted a cross-sectional study on the association between rotating night shift work characteristics, 6-sulfatoxymelatonin (MT6s) creatinine adjusted in a spot morning urine sample, and a computer-assisted measure of mammographic density in 640 nurses and midwives ages 40 to 60 years. The associations were evaluated using regression models adjusted for age, body mass index, menopausal status, age at menopause, age at menarche, smoking, and the calendar season of the year when mammography was conducted. RESULTS: The adjusted means of percentage of mammographic density and absolute density were slightly higher among women working rotating night shifts but not statistically significant [percentage of mammographic density = 23.6%, 95% confidence interval (CI), 21.9%-25.4% vs. 22.5%, 95% CI, 20.8%-24.3%; absolute density = 23.9 cm(2), 95% CI, 21.4-26.4 cm(2) vs. 21.8 cm(2), 95% CI, 19.4-24.3 cm(2) in rotating night shift and day shift nurses, respectively). There were no significant associations between the current or cumulative rotating night shift work exposure metrics and mammographic density. No association was observed between morning MT6s and mammographic density. CONCLUSIONS: The hypothesis on the link between rotating night shift work, melatonin synthesis disruption, and mammographic density is not supported by the results of the present study. IMPACT: It is unlikely that the development of breast cancer in nurses working rotating night shifts is mediated by an increase in mammographic density.
Address Department of Environmental Epidemiology, Nofer Institute of Occupational Medicine, Lodz, Poland. beatap@imp.lodz.pl
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1055-9965 ISBN Medium
Area Expedition Conference
Notes PMID:22539602 Approved no
Call Number IDA @ john @ Serial 159
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