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Author Higuchi, S.; Nagafuchi, Y.; Lee, S.-I.; Harada, T. url  doi
openurl 
  Title Influence of Light at Night on Melatonin Suppression in Children Type Journal Article
  Year 2014 Publication The Journal of Clinical Endocrinology and Metabolism Abbreviated Journal J Clin Endocrinol Metab  
  Volume 99 Issue (down) 9 Pages 3298-3303  
  Keywords melatonin; light at night; photobiology; children  
  Abstract Context: The sensitivity of melatonin to light suppression is expected to be higher in children since children have large pupils and pure crystal lenses. However, melatonin suppression by light in children remains unclear. Objective: We investigated whether light-induced melatonin suppression in children is larger than that in adults. Methods: Thirty-three healthy primary school children (mean age: 7.4 +/- 1.8 yr) and 29 healthy adults (mean age: 41.2 +/- 4.8 yr) participated in two experiments. In the first experiment, salivary melatonin concentrations in 13 children and 13 adults were measured at night under a dim light (< 30 lx) and moderately bright light (580 lx) in an experimental facility. Pupil diameters were also measured under dim light and bright light. In the second experiment, melatonin concentrations in 20 children and 16 adults were measured under dim light in the experimental facility and under room light at home (illuminance 140.0 +/- 82.7 lx). Results: In the experiment 1, the melatonin concentration was significantly decreased by exposure to moderately bright light in both adults and children. Melatonin suppression was significantly larger in children (88.2%, n=5) than in adults (46.3%, n=6) (p<0.01), although the data for some participants were excluded because melatonin concentrations had not yet risen. In the experiment 2, melatonin secretion was significantly suppressed by room light at home in children (n=15) (p<0.05) but not in adults (n=11). Conclusion: We found that the percentage of melatonin suppression by light in children was almost twice that in adults, suggesting that melatonin in children is more sensitive than that in adults to light at night.  
  Address Department of Human Science, Faculty of Design, Kyushu University, Fukuoka, Japan  
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  Series Volume Series Issue Edition  
  ISSN 0021-972X ISBN Medium  
  Area Expedition Conference  
  Notes PMID:24840814 Approved no  
  Call Number IDA @ john @ Serial 300  
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Author Kessel, L.; Siganos, G.; Jorgensen, T.; Larsen, M. url  doi
openurl 
  Title Sleep disturbances are related to decreased transmission of blue light to the retina caused by lens yellowing Type Journal Article
  Year 2011 Publication Sleep Abbreviated Journal Sleep  
  Volume 34 Issue (down) 9 Pages 1215-1219  
  Keywords Adult; Age Factors; Aging/*pathology/physiology; Circadian Rhythm/physiology; Cross-Sectional Studies; Female; Fluorometry; Humans; Lens, Crystalline/*pathology/physiopathology; *Light; Male; Middle Aged; Retina/*physiopathology; Risk Factors; *Scattering, Radiation; Sleep Disorders/*etiology; Circadian rhythm; cataract; melanopsin; sleep; blue light  
  Abstract STUDY OBJECTIVES: Sleep pattern and circadian rhythms are regulated via the retinohypothalamic tract in response to stimulation of a subset of retinal ganglion cells, predominantly by blue light (450-490 nm). With age, the transmission of blue light to the retina is reduced because of the aging process of the human lens, and this may impair the photoentrainment of circadian rhythm leading to sleep disorders. The aim of the study was to examine the association between lens aging and sleep disorders. DESIGN: Cross-sectional population based study. SETTING: The study was performed at the Research Center for Prevention and Health, Glostrup Hospital, Denmark and at the Department of Ophthalmology, Herlev Hospital, Denmark. PARTICIPANTS: An age- and sex-stratified sample of 970 persons aged 30 to 60 years of age drawn from a sample randomly selected from the background population. INTERVENTIONS: Not applicable. MEASUREMENTS AND RESULTS: Sleep disturbances were evaluated by a combination of questionnaire and the use of prescription sleeping medication. Lens aging (transmission and yellowing) was measured objectively by lens autofluorometry. The risk of sleep disturbances was significantly increased when the transmission of blue light to the retina was low, even after correction for the effect of age and other confounding factors such as smoking habits, diabetes mellitus, gender, and the risk of ischemic heart disease (P < 0.0001). CONCLUSIONS: Filtration of blue light by the aging lens was significantly associated with an increased risk of sleep disturbances. We propose that this is a result of disturbance of photoentrainment of circadian rhythms.  
  Address Department of Ophthalmology, Glostrup Hospital, University of Copenhagen, Denmark. line.kessel@dadlnet.dk  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 0161-8105 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21886359; PMCID:PMC3157663 Approved no  
  Call Number IDA @ john @ Serial 344  
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Author Bachleitner, W.; Kempinger, L.; Wülbeck, C.; Rieger, D.; Helfrich-Förster, C. url  doi
openurl 
  Title Moonlight shifts the endogenous clock of Drosophila melanogaster Type Journal Article
  Year 2007 Publication PNAS Abbreviated Journal  
  Volume 104 Issue (down) 9 Pages 3538–3543  
  Keywords Animals; circadian rhythm; dual; oscillator model; PERIOD; synchronization; TIMELESS  
  Abstract The ability to be synchronized by light–dark cycles is a fundamental property of circadian clocks. Although there are indications that circadian clocks are extremely light-sensitive and that they can be set by the low irradiances that occur at dawn and dusk, this has not been shown on the cellular level. Here, we demonstrate that a subset of Drosophila's pacemaker neurons responds to nocturnal dim light. At a nighttime illumination comparable to quarter-moonlight intensity, the flies increase activity levels and shift their typical morning and evening activity peaks into the night. In parallel, clock protein levels are reduced, and clock protein rhythms shift in opposed direction in subsets of the previously identified morning and evening pacemaker cells. No effect was observed on the peripheral clock in the eye. Our results demonstrate that the neurons driving rhythmic behavior are extremely light-sensitive and capable of shifting activity in response to the very low light intensities that regularly occur in nature. This sensitivity may be instrumental in adaptation to different photoperiods, as was proposed by the morning and evening oscillator model of Pittendrigh and Daan. We also show that this adaptation depends on retinal input but is independent of cryptochrome.  
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  Call Number LoNNe @ christopher.kyba @ Serial 405  
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Author Bhatti, P.; Mirick, D.K.; Davis, S. url  doi
openurl 
  Title Invited commentary: Shift work and cancer Type Journal Article
  Year 2012 Publication American Journal of Epidemiology Abbreviated Journal Am J Epidemiol  
  Volume 176 Issue (down) 9 Pages 760-3; discussion 764-5  
  Keywords Human Health; Circadian Rhythm; Humans; Male; *Men's Health; Neoplasms/*epidemiology; Occupations/*statistics & numerical data; Personnel Staffing and Scheduling/*statistics & numerical data  
  Abstract In this issue of the Journal, Parent et al. (Am J Epidemiol. 2012;176(9):751-759) report significant associations between night-shift work and risk of cancer at several sites among men. These findings not only address the need for shift-work studies that evaluate cancers other than breast and prostate cancer but also support the increasing concern that the negative effects of shift work may be broadly applicable to risk of many cancers via the direct oncostatic properties of melatonin. Studies of shift work have been limited by a lack of detailed data for determining which aspects of this multifaceted exposure may be associated with increased cancer risk. Additionally, the influence of individual-level characteristics, such as preference for daytime activity versus nighttime activity or chronotype, has not been considered. In moving forward, launching new cohort studies of shift work and cancer risk is the most tenable approach, though it will be limited by the years of follow-up required in order to accrue adequate numbers of cancer cases. Studies incorporating biomarkers of effect are useful for providing immediate information that can aid not only in identifying the underlying mechanisms of the shift-work-cancer association but also in interpreting existing epidemiologic data and informing the design of future epidemiologic studies of cancer risk.  
  Address Program in Epidemiology, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA. pbhatti@fhcrc.org  
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  ISSN 0002-9262 ISBN Medium  
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  Notes PMID:23035018 Approved no  
  Call Number LoNNe @ christopher.kyba @ Serial 507  
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Author Lockley, S.W.; Brainard, G.C.; Czeisler, C.A. url  doi
openurl 
  Title High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light Type Journal Article
  Year 2003 Publication The Journal of Clinical Endocrinology and Metabolism Abbreviated Journal J Clin Endocrinol Metab  
  Volume 88 Issue (down) 9 Pages 4502-4505  
  Keywords Human Health; Adult; Area Under Curve; Circadian Rhythm/*radiation effects; Female; Humans; *Light; Male; Melatonin/*metabolism; Pineal Gland/metabolism/radiation effects; Saliva/metabolism; Non-programmatic  
  Abstract The endogenous circadian oscillator in mammals, situated in the suprachiasmatic nuclei, receives environmental photic input from specialized subsets of photoreceptive retinal ganglion cells. The human circadian pacemaker is exquisitely sensitive to ocular light exposure, even in some people who are otherwise totally blind. The magnitude of the resetting response to white light depends on the timing, intensity, duration, number and pattern of exposures. We report here that the circadian resetting response in humans, as measured by the pineal melatonin rhythm, is also wavelength dependent. Exposure to 6.5 h of monochromatic light at 460 nm induces a two-fold greater circadian phase delay than 6.5 h of 555 nm monochromatic light of equal photon density. Similarly, 460 nm monochromatic light causes twice the amount of melatonin suppression compared to 555 nm monochromatic light, and is dependent on the duration of exposure in addition to wavelength. These studies demonstrate that the peak of sensitivity of the human circadian pacemaker to light is blue-shifted relative to the three-cone visual photopic system, the sensitivity of which peaks at approximately 555 nm. Thus photopic lux, the standard unit of illuminance, is inappropriate when quantifying the photic drive required to reset the human circadian pacemaker.  
  Address Division of Sleep Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts 02115, USA  
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  Language English Summary Language Original Title  
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  ISSN 0021-972X ISBN Medium  
  Area Expedition Conference  
  Notes PMID:12970330 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 778  
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