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Author Watson, L.A.; Phillips, A.J.K.; Hosken, I.T.; McGlashan, E.M.; Anderson, C.; Lack, L.C.; Lockley, S.W.; Rajaratnam, S.M.W.; Cain, S.W.
Title Increased sensitivity of the circadian system to light in delayed sleep-wake phase disorder Type Journal Article
Year 2018 Publication The Journal of Physiology Abbreviated Journal J Physiol
Volume in press Issue Pages
Keywords Human Health
Abstract KEY POINTS: This is the first study to demonstrate an altered circadian phase shifting response in a circadian rhythm sleep disorder. Patients with Delayed Sleep-Wake Phase Disorder (DSWPD) demonstrate greater sensitivity of the circadian system to the phase delaying effects of light. Increased circadian sensitivity to light is associated with later circadian timing within both control and DSWPD groups. DSWPD patients had a greater sustained pupil response after light exposure. Treatments for DSWPD should consider sensitivity of the circadian system to light as a potential underlying vulnerability, making patients susceptible to relapse. ABSTRACT: Patients with Delayed Sleep-Wake Phase Disorder (DSWPD) exhibit delayed sleep-wake behavior relative to desired bedtime, often leading to chronic sleep restriction and daytime dysfunction. The majority of DSWPD patients also display delayed circadian timing in the melatonin rhythm. Hypersensitivity of the circadian system to phase delaying light is a plausible physiological basis for DSWPD vulnerability. We compared the phase shifting response to a 6.5-h light exposure ( approximately 150 lux) between male patients with diagnosed DSWPD (n = 10; aged 22.4 +/- 3.3 years) and male healthy controls (n = 11; aged 22.4 +/- 2.4 years). Salivary dim light melatonin onset (DLMO) was measured under controlled conditions in dim light (<3 lux) before and after light exposure. Correcting for the circadian time of the light exposure, DSWPD patients exhibited 31.5% greater phase delay shifts than healthy controls. In both groups, a later initial phase of the melatonin rhythm was associated with greater magnitude of phase shifts, indicating that increased circadian sensitivity to light may be a factor that contributes to delayed phase, even in non-clinical groups. DSWPD patients also had reduced pupil size following the light exposure, and showed a trend towards increased melatonin suppression during light exposure. These findings indicate that, for patients with DSWPD, assessment of light sensitivity may be an important factor that can inform behavioral therapy, including minimization of exposure to phase-delaying night-time light. This article is protected by copyright. All rights reserved.
Address Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
Corporate Author Thesis
Publisher Place of Publication Editor
Language (down) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3751 ISBN Medium
Area Expedition Conference
Notes PMID:30281150 Approved no
Call Number GFZ @ kyba @ Serial 2026
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Author Stevens, R.G.
Title Comment on 'Domestic light at night and breast cancer risk: a prospective analysis of 105 000 UK women in the Generations Study' Type Journal Article
Year 2018 Publication British Journal of Cancer Abbreviated Journal Br J Cancer
Volume in press Issue Pages
Keywords Commentary; Human Health
Abstract
Address University of Connecticut, School of Medicine, 263 Farmington Avenue, Farmington, CT, 06032, USA. bugs@uchc.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language (down) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0007-0920 ISBN Medium
Area Expedition Conference
Notes PMID:30283145 Approved no
Call Number GFZ @ kyba @ Serial 2035
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Author Leise, T.L.; Goldberg, A.; Michael, J.; Montoya, G.; Solow, S.; Molyneux, P.; Vetrivelan, R.; Harrington, M.E.
Title Recurring circadian disruption alters circadian clock sensitivity to resetting Type Journal Article
Year 2018 Publication The European Journal of Neuroscience Abbreviated Journal Eur J Neurosci
Volume in press Issue Pages
Keywords Animals
Abstract A single phase advance of the light:dark (LD) cycle can temporarily disrupt synchrony of neural circadian rhythms within the suprachiasmatic nucleus (SCN) and between the SCN and peripheral tissues. Compounding this, modern life can involve repeated disruptive light conditions. To model chronic disruption to the circadian system, we exposed male mice to more than a month of a 20 h light cycle (LD10:10), which mice typically cannot entrain to. Control animals were housed under LD12:12. We measured locomotor activity and body temperature rhythms in vivo, and rhythms of PER2::LUC bioluminescence in SCN and peripheral tissues ex vivo. Unexpectedly, we discovered strong effects of the time of dissection on circadian phase of PER2::LUC bioluminescent rhythms, which varied across tissues. White adipose tissue was strongly reset by dissection, while thymus phase appeared independent of dissection timing. Prior light exposure impacted the SCN, resulting in strong resetting of SCN phase by dissection for mice housed under LD10:10, and weak phase shifts by time of dissection in SCN from control LD12:12 mice. These findings suggest that exposure to circadian disruption may desynchronize SCN neurons, increasing network sensitivity to perturbations. We propose that tissues with a weakened circadian network, such as the SCN under disruptive light conditions, or with little to no coupling, e.g., some peripheral tissues, will show increased resetting effects. In particular, exposure to light at inconsistent circadian times on a recurring weekly basis disrupts circadian rhythms and alters sensitivity of the SCN neural pacemaker to dissection time. This article is protected by copyright. All rights reserved.
Address Neuroscience Program, Smith College, Northampton, MA, 01063, USA
Corporate Author Thesis
Publisher Place of Publication Editor
Language (down) 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:30269396 Approved no
Call Number GFZ @ kyba @ Serial 2036
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Author Kozaki, T.; Hidaka, Y.; Takakura, J.-Y.; Kusano, Y.
Title Suppression of salivary melatonin secretion under 100-Hz flickering and non-flickering blue light Type Journal Article
Year 2018 Publication Journal of Physiological Anthropology Abbreviated Journal J Physiol Anthropol
Volume 37 Issue 1 Pages 23
Keywords Human Health
Abstract BACKGROUND: Bright light at night is known to suppress melatonin secretion. Novel photoreceptors named intrinsically photosensitive retinal ganglion cells (ipRGCs) are mainly responsible for projecting dark/bright information to the suprachiasmatic nucleus and thus regulating the circadian system. However, it has been shown that the amplitude of the electroretinogram of ipRGCs is considerably lower under flickering light at 100 Hz than at 1-5 Hz, suggesting that flickering light may also affect the circadian system. Therefore, in this study, we evaluated light-induced melatonin suppression under flickering and non-flickering light. METHODS: Twelve male participants between the ages of 20 and 23 years (mean +/- S.D. = 21.6 +/- 1.5 years) were exposed to three light conditions (dim, 100-Hz flickering, and non-flickering blue light) from 1:00 A.M. to 2:30 A.M., and saliva samples were obtained just before 1:00 A.M. and at 1:15, 1:30, 2:00, and 2:30 A.M. RESULTS: A repeated measures t test with Bonferroni correction showed that at 1:15 A.M., melatonin concentrations were significantly lower following exposure to non-flickering light compared with dim light, whereas there was no significant difference between the dim and 100-Hz flickering light conditions. By contrast, after 1:30 A.M., the mean melatonin concentrations were significantly lower under both 100-Hz flickering and non-flickering light than under dim light. CONCLUSION: Although melatonin suppression rate tended to be lower under 100-Hz flickering light than under non-flickering light at the initial 15 min of the light exposure, the present study suggests that 100-Hz flickering light may have the same impact on melatonin secretion as non-flickering light.
Address Department of Health and Nutrition Sciences, Nishikyushu University, Kanzaki, Japan
Corporate Author Thesis
Publisher Place of Publication Editor
Language (down) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1880-6791 ISBN Medium
Area Expedition Conference
Notes PMID:30340620 Approved no
Call Number GFZ @ kyba @ Serial 2039
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Author Pulgar, J.; Zeballos, D.; Vargas, J.; Aldana, M.; Manriquez, P.; Manriquez, K.; Quijon, P.A.; Widdicombe, S.; Anguita, C.; Quintanilla, D.; Duarte, C.
Title Endogenous cycles, activity patterns and energy expenditure of an intertidal fish is modified by artificial light pollution at night (ALAN) Type Journal Article
Year 2018 Publication Environmental Pollution (Barking, Essex : 1987) Abbreviated Journal Environ Pollut
Volume 244 Issue Pages 361-366
Keywords Animals
Abstract The increase of global light emissions in recent years has highlighted the need for urgent evaluation of their impacts on the behaviour, ecology and physiology of organisms. Numerous species exhibit daily cycles or strong scototaxic behaviours that could potentially be influenced if natural lighting conditions or cycles are disrupted. Artificial Light Pollution at Night (ALAN) stands for situations where artificial light alters natural light-dark cycles, as well as light intensities and wavelengths. ALAN is increasingly recognized as a potential threat to biodiversity, mainly because a growing number of studies are demonstrating its influence on animal behaviour, migration, reproduction and biological interactions. Most of these studies have focused on terrestrial organisms and ecosystems with studies on the effects of ALAN on marine ecosystems being more occasional. However, with the increasing human use and development of the coastal zone, organisms that inhabit shallow coastal or intertidal systems could be at increasing risk from ALAN. In this study we measured the levels of artificial light intensity in the field and used these levels to conduct experimental trials to determine the impact of ALAN on an intertidal fish. Specifically, we measured ALAN effects on physiological performance (oxygen consumption) and behaviour (activity patterns) of “Baunco” the rockfish Girella laevifrons, one of the most abundant and ecologically important intertidal fish in the Southeastern Pacific littoral. Our results indicated that individuals exposed to ALAN exhibited increased oxygen consumption and activity when compared with control animals. Moreover, those fish exposed to ALAN stopped displaying the natural (circatidal and circadian) activity cycles that were observed in control fish throughout the experiment. These changes in physiological function and behaviour could have serious implications for the long-term sustainability of fish populations and indirect impacts on intertidal communities in areas affected by ALAN.
Address Departamento de Ecologia & Biodiversidad, Facultad de Ciencia de la Vida, Universidad Andres Bello, Chile; Center for the Study of Multiple-Drivers on Marine Socio-Ecological Systems (MUSELS), Universidad de Concepcion, Concepcion, Chile
Corporate Author Thesis
Publisher Place of Publication Editor
Language (down) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0269-7491 ISBN Medium
Area Expedition Conference
Notes PMID:30352350 Approved no
Call Number GFZ @ kyba @ Serial 2043
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