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Author Arendt, J.; Middleton, B. url  doi
openurl 
  Title Human seasonal and circadian studies in Antarctica (Halley, 75 degrees S) Type Journal Article
  Year 2018 Publication General and Comparative Endocrinology Abbreviated Journal Gen Comp Endocrinol  
  Volume 258 Issue Pages 250-258  
  Keywords Human Activities; Acclimatization/*physiology; Actigraphy; Adult; Antarctic Regions; Behavior/*physiology; Circadian Rhythm/*physiology; Darkness; Female; Heart Rate/physiology; Humans; Libido; Light; Male; Melatonin/blood; Photoperiod; *Seasons; Sleep/physiology; Young Adult; *Antarctica; *Circadian; *Light; *Melatonin; *Seasonal  
  Abstract Living for extended periods in Antarctica exposes base personnel to extremes of daylength (photoperiod) and temperature. At the British Antarctic Survey base of Halley, 75 degrees S, the sun does not rise for 110 d in the winter and does not set for 100 d in summer. Photoperiod is the major time cue governing the timing of seasonal events such as reproduction in many species. The neuroendocrine signal providing photoperiodic information to body physiology is the duration of melatonin secretion which reflects the length of the night: longer in the short days of winter and shorter in summer. Light of sufficient intensity and spectral composition serves to suppress production of melatonin and to set the circadian timing and the duration of the rhythm. In humans early observations suggested that bright (>2000 lux) white light was needed to suppress melatonin completely. Shortly thereafter winter depression (Seasonal Affective Disorder or SAD) was described, and its successful treatment by an artificial summer photoperiod of bright white light, sufficient to shorten melatonin production. At Halley dim artificial light intensity during winter was measured, until 2003, at a maximum of approximately 500 lux in winter. Thus a strong seasonal and circadian time cue was absent. It seemed likely that winter depression would be common in the extended period of winter darkness and could be treated with an artificial summer photoperiod. These observations, and predictions, inspired a long series of studies regarding human seasonal and circadian status, and the effects of light treatment, in a small overwintering, isolated community, living in the same conditions for many months at Halley. We found little evidence of SAD, or change in duration of melatonin production with season. However the timing of the melatonin rhythm itself, and/or that of its metabolite 6-sulphatoxymelatonin (aMT6s), was used as a primary marker of seasonal, circadian and treatment changes. A substantial phase delay of melatonin in winter was advanced to summer phase by a two pulse 'skeleton' bright white light treatment. Subsequently a single morning pulse of bright white light was effective with regard to circadian phase and improved daytime performance. The circadian delay evidenced by melatonin was accompanied by delayed sleep (logs and actigraphy): poor sleep is a common complaint in Polar regions. Appropriate extra artificial light, both standard white, and blue enriched, present throughout the day, effectively countered delay in sleep timing and the aMT6s rhythm. The most important factor appeared to be the maximum light experienced. Another manifestation of the winter was a decline in self-rated libido (men only on base at this time). Women on the base showed lower aspects of physical and mental health compared to men. Free-running rhythms were seen in some subjects following night shift, but were rarely found at other times, probably because this base has strongly scheduled activity and leisure time. Complete circadian adaptation during a week of night shift, also seen in a similar situation on North Sea oil rigs, led to problems readapting back to day shift in winter, compared to summer. Here again timed light treatment was used to address the problem. Sleep, alertness and waking performance are critically dependent on optimum circadian phase. Circadian desynchrony is associated with increased risk of major disease in shift workers. These studies provide some groundwork for countering/avoiding circadian desynchrony in rather extreme conditions.  
  Address Biochemistry and Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK. Electronic address: b.middleton@surrey.ac.uk  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN (up) 0016-6480 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:28526480 Approved no  
  Call Number IDA @ john @ Serial 2248  
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Author Menegaux, F.; Truong, T.; Anger, A.; Cordina-Duverger, E.; Lamkarkach, F.; Arveux, P.; Kerbrat, P.; Fevotte, J.; Guenel, P. url  doi
openurl 
  Title Night work and breast cancer: a population-based case-control study in France (the CECILE study) Type Journal Article
  Year 2013 Publication International Journal of Cancer. Journal International du Cancer Abbreviated Journal Int J Cancer  
  Volume 132 Issue 4 Pages 924-931  
  Keywords Human Health; Adult; Aged; Breast Neoplasms/epidemiology/*etiology; Case-Control Studies; *Circadian Rhythm; Employment; Female; France/epidemiology; Humans; Middle Aged; Occupations; Pregnancy; Risk Factors; *Work Schedule Tolerance  
  Abstract Night work involving disruption of circadian rhythm was suggested as a possible cause of breast cancer. We examined the role of night work in a large population-based case-control study carried out in France between 2005 and 2008. Lifetime occupational history including work schedules of each night work period was elicited in 1,232 cases of breast cancer and 1,317 population controls. Thirteen percent of the cases and 11% of the controls had ever worked on night shifts (OR = 1.27 [95% confidence interval = 0.99-1.64]). Odds ratios were 1.35 [1.01-1.80] in women who worked on overnight shifts, 1.40 [1.01-1.92] in women who had worked at night for 4.5 or more years, and 1.43 [1.01-2.03] in those who worked less than three nights per week on average. The odds ratio was 1.95 [1.13-3.35] in women employed in night work for >4 years before their first full-term pregnancy, a period where mammary gland cells are incompletely differentiated and possibly more susceptible to circadian disruption effects. Our results support the hypothesis that night work plays a role in breast cancer, particularly in women who started working at night before first full-term pregnancy.  
  Address Inserm, CESP Center for research in Epidemiology and Population Health, U1018, Environmental Epidemiology of Cancer, Villejuif, France; Univ Paris-Sud, UMRS 1018, Villejuif, France  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  ISSN (up) 0020-7136 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:22689255 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 781  
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Author Gooley, J.J.; Chamberlain, K.; Smith, K.A.; Khalsa, S.B.S.; Rajaratnam, S.M.W.; Van Reen, E.; Zeitzer, J.M.; Czeisler, C.A.; Lockley, S.W. url  doi
openurl 
  Title Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans Type Journal Article
  Year 2011 Publication The Journal of Clinical Endocrinology and Metabolism Abbreviated Journal J Clin Endocrinol Metab  
  Volume 96 Issue 3 Pages E463-72  
  Keywords Adolescent; Adult; Female; Humans; *Light; *Lighting; Male; Melatonin/*blood; Sleep/physiology; Time Factors; Young Adult  
  Abstract CONTEXT: Millions of individuals habitually expose themselves to room light in the hours before bedtime, yet the effects of this behavior on melatonin signaling are not well recognized. OBJECTIVE: We tested the hypothesis that exposure to room light in the late evening suppresses the onset of melatonin synthesis and shortens the duration of melatonin production. DESIGN: In a retrospective analysis, we compared daily melatonin profiles in individuals living in room light (<200 lux) vs. dim light (<3 lux). PATIENTS: Healthy volunteers (n = 116, 18-30 yr) were recruited from the general population to participate in one of two studies. SETTING: Participants lived in a General Clinical Research Center for at least five consecutive days. INTERVENTION: Individuals were exposed to room light or dim light in the 8 h preceding bedtime. OUTCOME MEASURES: Melatonin duration, onset and offset, suppression, and phase angle of entrainment were determined. RESULTS: Compared with dim light, exposure to room light before bedtime suppressed melatonin, resulting in a later melatonin onset in 99.0% of individuals and shortening melatonin duration by about 90 min. Also, exposure to room light during the usual hours of sleep suppressed melatonin by greater than 50% in most (85%) trials. CONCLUSIONS: These findings indicate that room light exerts a profound suppressive effect on melatonin levels and shortens the body's internal representation of night duration. Hence, chronically exposing oneself to electrical lighting in the late evening disrupts melatonin signaling and could therefore potentially impact sleep, thermoregulation, blood pressure, and glucose homeostasis.  
  Address Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, 221 Longwood Avenue, Boston, Massachusetts 02115, USA. gmsjjg@nus.edu  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  ISSN (up) 0021-972X ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21193540; PMCID:PMC3047226 Approved no  
  Call Number IDA @ john @ Serial 139  
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Author Obayashi, K.; Saeki, K.; Iwamoto, J.; Okamoto, N.; Tomioka, K.; Nezu, S.; Ikada, Y.; Kurumatani, N. url  doi
openurl 
  Title Exposure to light at night, nocturnal urinary melatonin excretion, and obesity/dyslipidemia in the elderly: a cross-sectional analysis of the HEIJO-KYO study Type Journal Article
  Year 2013 Publication The Journal of Clinical Endocrinology and Metabolism Abbreviated Journal J Clin Endocrinol Metab  
  Volume 98 Issue 1 Pages 337-344  
  Keywords *Aged; Aged, 80 and over; Case-Control Studies; *Circadian Rhythm/physiology; Cross-Sectional Studies; Dyslipidemias/complications/metabolism/*urine; Female; Humans; Japan; *Light; Male; Melatonin/secretion/*urine; Obesity/complications/metabolism/*urine; Photoperiod  
  Abstract CONTEXT: Obesity and exposure to light at night (LAN) have increased globally. Although LAN suppresses melatonin secretion and disturbs body mass regulation in experimental settings, its associations with melatonin secretion, obesity, and other metabolic consequences in uncontrolled home settings remain unclear. OBJECTIVE: The aim of this study was to determine the association of exposure to LAN in an uncontrolled home setting with melatonin secretion, obesity, dyslipidemia, and diabetes. DESIGN AND PARTICIPANTS: A cross-sectional study was performed in 528 elderly individuals (mean age, 72.8 yr). MEASURES: The intensity of LAN in the bedroom was measured at 1-min intervals during two consecutive nights, along with overnight urinary melatonin excretion and metabolic parameters. RESULTS: Compared with the Dim group (average <3 lux; n = 383), the LAN group (average >/=3 lux; n = 145) showed significantly higher body weight (adjusted mean, 58.8 vs. 56.6 kg; P = 0.01), body mass index (23.3 vs. 22.7 kg/m(2); P = 0.04), waist circumference (84.9 vs. 82.8 cm; P = 0.01), triglyceride levels (119.7 vs. 99.5 mg/dl; P < 0.01), and low-density lipoprotein cholesterol levels (128.6 vs. 122.2 mg/dl; P = 0.04), and showed significantly lower high-density lipoprotein cholesterol levels (57.4 vs. 61.3 mg/dl; P = 0.02). These associations were independent of numerous potential confounders, including urinary melatonin excretion. Furthermore, LAN exposure is associated with higher odds ratios (ORs) for obesity (body mass index: OR, 1.89; P = 0.02; abdominal: OR, 1.62; P = 0.04) and dyslipidemia (OR, 1.72; P = 0.02) independent of demographic and socioeconomic parameters. In contrast, urinary melatonin excretion and glucose parameters did not show significant differences between the two groups. CONCLUSIONS: Exposure to LAN in an uncontrolled home setting is associated with impaired obese and lipid parameters independent of nocturnal urinary melatonin excretion in elderly individuals. Moreover, LAN exposure is associated with higher ORs for obesity and dyslipidemia independent of demographic and socioeconomic parameters.  
  Address Department of Community Health and Epidemiology, Nara Medical University School of Medicine, 840 Shijocho, Kashiharashi, Nara, 634-8521, Japan. obayashi@naramed-u.ac.jp  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN (up) 0021-972X ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23118419 Approved no  
  Call Number IDA @ john @ Serial 168  
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Author Chellappa, S.L.; Viola, A.U.; Schmidt, C.; Bachmann, V.; Gabel, V.; Maire, M.; Reichert, C.F.; Valomon, A.; Gotz, T.; Landolt, H.-P.; Cajochen, C. url  doi
openurl 
  Title Human melatonin and alerting response to blue-enriched light depend on a polymorphism in the clock gene PER3 Type Journal Article
  Year 2012 Publication The Journal of Clinical Endocrinology and Metabolism Abbreviated Journal J Clin Endocrinol Metab  
  Volume 97 Issue 3 Pages E433-7  
  Keywords Adult; Alleles; Cross-Over Studies; Female; Genotype; Homozygote; Humans; *Light; Male; Melatonin/*blood/genetics; *Minisatellite Repeats; Period Circadian Proteins/*genetics; *Polymorphism, Genetic; Questionnaires; Sleep/genetics; Wakefulness/*genetics  
  Abstract CONTEXT: Light exposure, particularly at the short-wavelength range, triggers several nonvisual responses in humans. However, the extent to which the melatonin-suppressing and alerting effect of light differs among individuals remains unknown. OBJECTIVE: Here we investigated whether blue-enriched polychromatic light impacts differentially on melatonin and subjective and objective alertness in healthy participants genotyped for the PERIOD3 (PER3) variable-number, tandem-repeat polymorphism. DESIGN, SETTING, AND PARTICIPANTS: Eighteen healthy young men homozygous for the PER3 polymorphism (PER3(5/5)and PER3(4/4)) underwent a balanced crossover design during the winter season, with light exposure to compact fluorescent lamps of 40 lux at 6500 K and at 2500 K during 2 h in the evening. RESULTS: In comparison to light at 2500 K, blue-enriched light at 6500 K induced a significant suppression of the evening rise in endogenous melatonin levels in PER3(5/5) individuals but not in PER3(4/4). Likewise, PER3(5/5) individuals exhibited a more pronounced alerting response to light at 6500 K than PER3(4/4) volunteers. Waking electroencephalographic activity in the theta range (5-7 Hz), a putative correlate of sleepiness, was drastically attenuated during light exposure at 6500 K in PER3(5/5) individuals as compared with PER3(4/4). CONCLUSIONS: We provide first evidence that humans homozygous for the PER3 5/5 allele are particularly sensitive to blue-enriched light, as indexed by the suppression of endogenous melatonin and waking theta activity. Light sensitivity in humans may be modulated by a clock gene polymorphism implicated in the sleep-wake regulation.  
  Address Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Wilhelm Kleinstrasse 27, CH-4012 Basel, Switzerland  
  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 (up) 0021-972X ISBN Medium  
  Area Expedition Conference  
  Notes PMID:22188742 Approved no  
  Call Number IDA @ john @ Serial 301  
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