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Author Dumont, M.; Beaulieu, C. url  doi
openurl 
  Title Light exposure in the natural environment: relevance to mood and sleep disorders Type Journal Article
  Year 2007 Publication Sleep Medicine Abbreviated Journal Sleep Med  
  Volume 8 Issue 6 Pages 557-565  
  Keywords Human Health; Affect; *Biological Clocks; *Circadian Rhythm; Humans; *Light; Mood Disorders/*etiology; Sleep Disorders, Circadian Rhythm/*complications; Wakefulness; Work Schedule Tolerance  
  Abstract In addition to being necessary for vision, light also plays a primary role in circadian physiology. Humans are diurnal animals and their biological clock synchronizes their physiological functions in such a way that functions associated with activity happen in the daytime while functions associated with rest occur at night. A misalignment between the endogenous circadian clock and the desired sleep schedule is the main cause of circadian sleep disorders; it may be involved in certain mood disorders as well. Since light is the main environmental cue used by the biological clock to set its own timing in relation to the day-night cycle, inappropriate light exposure can be involved in the physiopathology of circadian disorders. Conversely, when handled properly, controlled light exposure can be used to treat some mood and sleep disorders. While the earliest studies in the field focused solely on exposure to bright light, contemporary studies aim at understanding how the entire profile of light-dark exposure can influence the circadian clock and, consequently, mood, sleep, and vigilance quality. Following a brief summary of the main concepts underlying the non-visual effects of light, this paper presents some studies using ambulatory measurements of light exposure to illustrate how these concepts apply in real-life situations and discusses the clinical relevance of light exposure in the natural environment for mood, sleep, and circadian disorders.  
  Address Chronobiology Laboratory, Sacre-Coeur Hospital of Montreal, Montreal, Quebec, Canada H4J 1C5. marie.dumont@umontreal.ca  
  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 1389-9457 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17383230 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 736  
Permanent link to this record
 

 
Author Dumont, M.; Lanctot, V.; Cadieux-Viau, R.; Paquet, J. url  doi
openurl 
  Title Melatonin production and light exposure of rotating night workers Type Journal Article
  Year 2012 Publication Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 29 Issue 2 Pages 203-210  
  Keywords Adult; Animals; Circadian Rhythm/*physiology; Humans; *Light; Melatonin/*analogs & derivatives/*biosynthesis/urine; Neoplasms/etiology; *Photoperiod; Risk Factors; Sleep/physiology; *Work; Work Schedule Tolerance  
  Abstract Decreased melatonin production, due to acute suppression of pineal melatonin secretion by light exposure during night work, has been suggested to underlie higher cancer risks associated with prolonged experience of night work. However, the association between light exposure and melatonin production has never been measured in the field. In this study, 24-h melatonin production and ambulatory light exposure were assessed during both night-shift and day/evening-shift periods in 13 full-time rotating shiftworkers. Melatonin production was estimated with the excretion of urinary 6-sulfatoxymelatonin (aMT6s), and light exposure was measured with an ambulatory photometer. There was no difference in total 24-h aMT6s excretion between the two work periods. The night-shift period was characterized by a desynchrony between melatonin and sleep-wake rhythms, as shown by higher melatonin production during work and lower melatonin production during sleep when working night shifts than when working day/evening shifts. Light exposure during night work showed no correlation with aMT6s excreted during the night of work (p > .5), or with the difference in 24-h aMT6s excretion between the two work periods (p > .1). However, light exposure during night work was negatively correlated with total 24-h aMT6s excretion over the entire night-shift period (p < .01). In conclusion, there was no evidence of direct melatonin suppression during night work in this population. However, higher levels of light exposure during night work may have decreased total melatonin production, possibly by initiating re-entrainment and causing internal desynchrony. This interpretation is consistent with the proposition that circadian disruption, of which decreased melatonin production is only one of the adverse consequences, could be the mediator between night shiftwork and cancer risks.  
  Address Chronobiology Laboratory, Center for Advanced Research in Sleep Medicine, Sacre-Coeur Hospital of Montreal, Montreal, Quebec, Canada. marie.dumont@umontreal.ca  
  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 0742-0528 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:22324558 Approved no  
  Call Number IDA @ john @ Serial 138  
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Author Eisenstein, M. url  doi
openurl 
  Title Chronobiology: stepping out of time Type Journal Article
  Year 2013 Publication Nature Abbreviated Journal Nature  
  Volume 497 Issue 7450 Pages S10-2  
  Keywords Human Health; Animals; Benzofurans/therapeutic use; CLOCK Proteins/genetics/metabolism; Circadian Rhythm/genetics/*physiology; Cyclopropanes/therapeutic use; Efficiency/physiology; Humans; Melatonin/agonists/metabolism; Obesity/metabolism; Sleep/genetics/*physiology; Suprachiasmatic Nucleus/metabolism  
  Abstract  
  Address  
  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 0028-0836 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23698500 Approved no  
  Call Number LoNNe @ christopher.kyba @ Serial 500  
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Author Erren, T.C.; Reiter, R.J. url  doi
openurl 
  Title Light Hygiene: Time to make preventive use of insights--old and new--into the nexus of the drug light, melatonin, clocks, chronodisruption and public health Type Journal Article
  Year 2009 Publication Medical Hypotheses Abbreviated Journal Med Hypotheses  
  Volume 73 Issue 4 Pages 537-541  
  Keywords Human Health; Chronobiology Phenomena/*physiology/*radiation effects; Circadian Rhythm/*physiology/radiation effects; Humans; *Light; Melatonin/*physiology; *Models, Biological; Phototherapy/*methods  
  Abstract Light is, clearly, a key to life on Earth and light, equally clearly, determines biological rhythmicity in organisms. Light does the latter by setting internal or endogenous clocks which allow a multitude of species, including man, to adjust their lives to changing external or environmental conditions. Critical changes over time occur from day to night and throughout the year. In this paper, we sum up how visible light provides electromagnetic information about environmental “time” via the ocular interface of newly discovered photoreceptive cells to a master clock in our brain, viz the suprachiasmatic nuclei [SCN], and how the SCN translate this input, with melatonin as a key biologic intermediary, into endogenous or biological time. We summarize experimental and epidemiological evidence suggesting how chronodisruption, a relevant disturbance of the temporal organization or order of physiology, endocrinology, metabolism and behaviour, is probably detrimental for human beings. On the basis of our synthesis, and in line with suggestions by other researchers voiced decades ago, light must, functionally, be considered as a drug equivalent. In this vein, the very timing, quality (wavelength), quantity (dose) and side effects, including chronodisruption, of light exposures can be critically important for health and disease in man. As a promising means to foster public health, we advocate an appropriate balance of exposures to the key Zeitgeber light in terms of “light hygiene”, implying strong and appropriate rather than weak and confusing temporal information. This focus on “light hygiene”, and thus on the key Zeitgeber light, does not mean to ignore that there are multiple entrainment pathways for our circadian clocks. Indeed, when dealing with light, chronodisruption and a multitude of adverse health effects, we ultimately need to consider Zeitgeber cues, and their possible interplay, beyond light alone. Confusions of the temporal programmes in humans can also stem from physical and social activities, stress and facets of food intake. And yet, since light possesses a rather unique and exclusive Zeitgeber role and in view of its ubiquitous nature, a specific, preventative focus on “light hygiene”, as a contribution to a general “Zeitgeber hygiene”, is warranted.  
  Address Institute and Policlinic for Occupational and Social Medicine, University of Cologne, Kerpener Strasse 62, 50937 Koln, Lindenthal, Germany. tim.erren@uni-koeln.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 0306-9877 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:19586725 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 742  
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Author Erren, T.C.; Morfeld, P.; Foster, R.G.; Reiter, R.J.; Gross, J.V.; Westermann, I.K. url  doi
openurl 
  Title Sleep and cancer: Synthesis of experimental data and meta-analyses of cancer incidence among some 1 500 000 study individuals in 13 countries Type Journal Article
  Year 2016 Publication Chronobiology International Abbreviated Journal Chronobiol Int  
  Volume 33 Issue 4 Pages 325-350  
  Keywords Human Health; Cancer; chronodisruption; meta-analyses; napping; sleep and circadian rhythm disruption (SCRD); sleep duration; sleep quality; sleep timing; Circadian Rhythm; sleep; Oncogenesis  
  Abstract Sleep and its impact on physiology and pathophysiology are researched at an accelerating pace and from many different angles. Experiments provide evidence for chronobiologically plausible links between chronodisruption and sleep and circadian rhythm disruption (SCRD), on the one hand, and the development of cancer, on the other. Epidemiological evidence from cancer incidence among some 1 500 000 study individuals in 13 countries regarding associations with sleep duration, napping or “poor sleep” is variable and inconclusive. Combined adjusted relative risks (meta-RRs) for female breast cancer, based on heterogeneous data, were 1.01 (95% CI: 0.97-1.06). Meta-RRs for cancers of the colorectum and of the lung in women and men and for prostate cancer were 1.08 (95% CI: 1.03-1.13), 1.11 (95% CI: 1.00-1.22) and 1.05 (95% CI: 0.83-1.33), respectively. The significantly increased meta-RRs for colorectal cancer, based on homogeneous data, warrant targeted study. However, the paramount epidemiological problem inhibiting valid conclusions about the associations between sleep and cancer is the probable misclassification of the exposures to facets of sleep over time. Regarding the inevitable conclusion that more research is needed to answer How are sleep and cancer linked in humans? we offer eight sets of recommendations for future studies which must take note of the complexity of multidirectional relationships.  
  Address a Institute and Policlinic for Occupational Medicine, Environmental Medicine and Prevention Research , University of Cologne , Cologne , Germany  
  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:27003385 Approved no  
  Call Number IDA @ john @ Serial 1407  
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