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Author Lee, E.; Kim, M. url  doi
openurl 
  Title Light and Life at Night as Circadian Rhythm Disruptors Type Journal Article
  Year 2019 Publication (up) Chronobiology in Medicine Abbreviated Journal  
  Volume 1 Issue 3 Pages 95-102  
  Keywords Review; Human Health  
  Abstract Light is an important entraining agent for endogenous circadian rhythms. Artificial light at night (ALAN) negatively influences the circadian system, inducing acute effects on sleep and cognition, as well as chronic endocrine-disrupting effects resulting in obesity, cardiovascular disease, diabetes, and cancer. Although shift workers may be exposed to extreme ALAN, its impact on their health is obscured by factors such as daylight exposure, meal and sleep scheduling, and physical and social behavior. Studies have revealed a significant increase in breast cancer in high ALAN-polluted areas, although the correlation with outdoor or indoor lighting conditions is controversial. Increasing use of electronic devices makes it difficult to assess ALAN exposure in the general population. The development of surrogate markers and critical parameters is crucial for health study by ALAN exposure, and such markers should include risk factors related to ALAN exposure. The present review considers articles investigating the risk of ALAN for shift workers, the general population, and users of electronic devices, and addresses susceptibility factors, including age, sex, and chronotype. Shift workers may be regarded as an extreme ALAN-exposure group, but the growing use of electronic devices and lifestyle changes in the general population make difficult to differentiate ALAN risks to health.  
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  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2903  
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Author Maroni, M.J.; Capri, K.M.; Cushman, A.V.; Monteiro De Pina, I.K.; Chasse, M.H.; Seggio, J.A. url  doi
openurl 
  Title Constant light alters serum hormone levels related to thyroid function in male CD-1 mice Type Journal Article
  Year 2018 Publication (up) Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 35 Issue 10 Pages 1456-1463  
  Keywords Animals  
  Abstract Disruptions to the circadian rhythm can lead to altered metabolism. Modification of thyroid function may be a reason why circadian misalignment may contribute to future metabolic disorders. We investigated whether circadian disruption through constant light (LL) can lead to variations in hormone levels associated with thyroid function. Mice were exposed to LL or a 12:12 Light:Dark (LD) cycle for 6 weeks; then glucose tolerance and thyroid hormone levels were measured at ZT 6 and ZT 18. There was day/night variation in glucose tolerance, but LL had no effect. LL reduced TSH, increased fT4, and abolished day/night variation in fT3 and leptin. These findings illustrate that LL alters thyroid-related hormones, providing evidence of a link between circadian disruption and thyroid function.  
  Address a Department of Biological Sciences , Bridgewater State University , Bridgewater , MA , USA  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 0742-0528 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:29953263 Approved no  
  Call Number GFZ @ kyba @ Serial 1958  
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Author Porcheret, K.; Wald, L.; Fritschi, L.; Gerkema, M.; Gordijn, M.; Merrrow, M.; Rajaratnam, S.M.W.; Rock, D.; Sletten, T.L.; Warman, G.; Wulff, K.; Roenneberg, T.; Foster, R.G. url  doi
openurl 
  Title Chronotype and environmental light exposure in a student population Type Journal Article
  Year 2018 Publication (up) Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 35 Issue 10 Pages 1365-1374  
  Keywords Human Health  
  Abstract In humans and most other species, changes in the intensity and duration of light provide a critical set of signals for the synchronisation of the circadian system to the astronomical day. The timing of activity within the 24 h day defines an individual's chronotype, i.e. morning, intermediate or evening type. The aim of this study was to investigate the associations between environmental light exposure, due to geographical location, on the chronotype of university students. Over 6 000 university students from cities in the Northern Hemisphere (Oxford, Munich and Groningen) and Southern Hemisphere (Perth, Melbourne and Auckland) completed the Munich ChronoType Questionnaire. In parallel, light measures (daily irradiance, timing of sunrise and sunset) were compiled from satellite or ground stations at each of these locations. Our data shows that later mid-sleep point on free days (corrected for oversleep on weekends MFSsc) is associated with (i) residing further from the equator, (ii) a later sunset, (iii) spending more time outside and (iv) waking from sleep significantly after sunrise. However, surprisingly, MSFsc did not correlate with daily light intensity at the different geographical locations. Although these findings appear to contradict earlier studies suggesting that in the wider population increased light exposure is associated with an earlier chronotype, our findings are derived exclusively from a student population aged between 17 and 26 years. We therefore suggest that the age and occupation of our population increase the likelihood that these individuals will experience relatively little light exposure in the morning whilst encountering more light exposure later in the day, when light has a delaying effect upon the circadian system.  
  Address a Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences , University of Oxford , Oxford , UK  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0742-0528 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:29913073 Approved no  
  Call Number GFZ @ kyba @ Serial 1962  
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Author Phipps-Nelson, J.; Redman, J.R.; Schlangen, L.J.M.; Rajaratnam, S.M.W. url  doi
openurl 
  Title Blue light exposure reduces objective measures of sleepiness during prolonged nighttime performance testing Type Journal Article
  Year 2009 Publication (up) Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 26 Issue 5 Pages 891-912  
  Keywords Human Health  
  Abstract This study examined the effects of nocturnal exposure to dim, narrowband blue light (460 nm, approximately 1 lux, 2 microW/cm2), compared to dim broad spectrum (white) ambient light ( approximately 0.2 lux, 0.5 microW/cm2), on subjective and objective indices of sleepiness during prolonged nighttime performance testing. Participants were also exposed to a red light (640 nm, approximately 1 lux, 0.7 microW/cm2) placebo condition. Outcome measures were driving simulator and psychomotor vigilance task (PVT) performance, subjective sleepiness, salivary melatonin, and electroencephalographic (EEG) activity. The study had a repeated-measures design, with three counterbalanced light conditions and a four-week washout period between each condition. Participants (n = 8) maintained a regular sleep-wake schedule for 14 days prior to the approximately 14 h laboratory study, which consisted of habituation to light conditions followed by neurobehavioral performance testing from 21:00 to 08:30 h under modified constant-routine conditions. A neurobehavioral test battery (2.5 h) was presented four times between 21:00 and 08:30 h, with a 30 min break between each. From 23:30 to 05:30 h, participants were exposed to blue or red light, or remained in ambient conditions. Compared to ambient light exposure, blue light exposure suppressed EEG slow wave delta (1.0-4.5 Hz) and theta (4.5-8 Hz) activity and reduced the incidence of slow eye movements. PVT reaction times were significantly faster in the blue light condition, but driving simulator measures, subjective sleepiness, and salivary melatonin levels were not significantly affected by blue light. Red light exposure, as compared to ambient light exposure, reduced the incidence of slow eye movements. The results demonstrate that low-intensity, blue light exposure can promote alertness, as measured by some of the objective indices used in this study, during prolonged nighttime performance testing. Low intensity, blue light exposure has the potential to be applied to situations where it is desirable to increase alertness but not practical or appropriate to use bright light, such as certain occupational settings.  
  Address School of Psychology, Psychiatry and Psychological Medicine, Monash University, Clayton, Victoria, Australia  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 0742-0528 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:19637049 Approved no  
  Call Number GFZ @ kyba @ Serial 2202  
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Author Agbaria, S.; Haim, A.; Fares, F.; Zubidat, A.E. url  doi
openurl 
  Title Epigenetic modification in 4T1 mouse breast cancer model by artificial light at night and melatonin – the role of DNA-methyltransferase Type Journal Article
  Year 2019 Publication (up) Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 36 Issue 5 Pages 629-643  
  Keywords Animals  
  Abstract Currently, one of the most disputed hypotheses regarding breast cancer (BC) development is exposure to short wavelength artificial light at night (ALAN) as multiple studies suggest a possible link between them. This link is suggested to be mediated by nocturnal melatonin suppression that plays an integral role in circadian regulations including cell division. The objective of the research was to evaluate effects of 1 x 30 min/midnight ALAN (134 micro Wcm(-2), 460 nm) with or without nocturnal melatonin supplement on tumor development and epigenetic responses in 4T1 tumor-bearing BALB/c mice. Mice were monitored for body mass (Wb) and tumor volume for 3 weeks and thereafter urine samples were collected at regular intervals for determining daily rhythms of 6-sulfatoxymelatonin (6-SMT). Finally, mice were sacrificed and the tumor, lungs, liver, and spleen were excised for analyzing the total activity of DNA methyltransferases (DNMT) and global DNA methylation (GDM) levels. Mice exposed to ALAN significantly reduced 6-SMT levels and increased Wb, tumor volume, and lung metastasis compared with controls. These effects were diminished by melatonin. The DNMT activity and GDM levels showed tissue-specific response. The enzymatic activity and GDM levels were lower in tumor and liver and higher in spleen and lungs under ALAN compared with controls. Our results suggest that ALAN disrupts the melatonin rhythm and potentially leading to increased BC burden by affecting DNMT activity and GDM levels. These data may also be applicable to early detection and management of BC by monitoring melatonin and GDM levels as early biomarker of ALAN circadian disruption.  
  Address b The Israeli Center for Interdisciplinary Research in Chronobiology , University of Haifa, Haifa , Israel; Zubidat3(at)013.net.il  
  Corporate Author Thesis  
  Publisher Taylor & Francis Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0742-0528 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:30746962 Approved no  
  Call Number IDA @ john @ Serial 2211  
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