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Author Summa, K.C.; Vitaterna, M.H.; Turek, F.W. url  doi
openurl 
  Title Environmental perturbation of the circadian clock disrupts pregnancy in the mouse Type Journal Article
  Year 2012 Publication PloS one Abbreviated Journal PLoS One  
  Volume 7 Issue 5 Pages e37668  
  Keywords Animals; Circadian Rhythm/*physiology; *Environment; Female; Locomotion/physiology; Mice; Mice, Inbred C57BL; Photoperiod; Pregnancy; Pregnancy Outcome; Reproduction/*physiology  
  Abstract BACKGROUND: The circadian clock has been linked to reproduction at many levels in mammals. Epidemiological studies of female shift workers have reported increased rates of reproductive abnormalities and adverse pregnancy outcomes, although whether the cause is circadian disruption or another factor associated with shift work is unknown. Here we test whether environmental disruption of circadian rhythms, using repeated shifts of the light:dark (LD) cycle, adversely affects reproductive success in mice. METHODOLOGY/PRINCIPAL FINDINGS: Young adult female C57BL/6J (B6) mice were paired with B6 males until copulation was verified by visual identification of vaginal plug formation. Females were then randomly assigned to one of three groups: control, phase-delay or phase-advance. Controls remained on a constant 12-hr light:12-hr dark cycle, whereas phase-delayed and phase-advanced mice were subjected to 6-hr delays or advances in the LD cycle every 5-6 days, respectively. The number of copulations resulting in term pregnancies was determined. Control females had a full-term pregnancy success rate of 90% (11/12), which fell to 50% (9/18; p<0.1) in the phase-delay group and 22% (4/18; p<0.01) in the phase-advance group. CONCLUSIONS/SIGNIFICANCE: Repeated shifting of the LD cycle, which disrupts endogenous circadian timekeeping, dramatically reduces pregnancy success in mice. Advances of the LD cycle have a greater negative impact on pregnancy outcomes and, in non-pregnant female mice, require longer for circadian re-entrainment, suggesting that the magnitude or duration of circadian misalignment may be related to the severity of the adverse impact on pregnancy. These results explicitly link disruptions of circadian entrainment to adverse pregnancy outcomes in mammals, which may have important implications for the reproductive health of female shift workers, women with circadian rhythm sleep disorders and/or women with disturbed circadian rhythms for other reasons.  
  Address Center for Sleep and Circadian Biology, Department of Neurobiology, Northwestern University, Evanston, Illinois, United States of America  
  Corporate Author Thesis  
  Publisher Place of Publication Editor (up)  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1932-6203 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:22649550; PMCID:PMC3359308 Approved no  
  Call Number IDA @ john @ Serial 92  
Permanent link to this record
 

 
Author Orbach, D.N.; Fenton, B. url  doi
openurl 
  Title Vision impairs the abilities of bats to avoid colliding with stationary obstacles Type Journal Article
  Year 2010 Publication PloS one Abbreviated Journal PLoS One  
  Volume 5 Issue 11 Pages e13912  
  Keywords Analysis of Variance; Animals; Chiroptera/*physiology; Cyclonic Storms; Echolocation/*physiology; Female; Flight, Animal/*physiology; Light; Male; Space Perception/physiology/radiation effects; Vision, Ocular/*physiology/radiation effects; Vocalization, Animal/physiology  
  Abstract BACKGROUND: Free-flying insectivorous bats occasionally collide with stationary objects they should easily detect by echolocation and avoid. Collisions often occur with lighted objects, suggesting ambient light may deleteriously affect obstacle avoidance capabilities. We tested the hypothesis that free-flying bats may orient by vision when they collide with some obstacles. We additionally tested whether acoustic distractions, such as “distress calls” of other bats, contributed to probabilities of collision. METHODOLOGY/PRINCIPAL FINDINGS: To investigate the role of visual cues in the collisions of free-flying little brown bats (Myotis lucifugus) with stationary objects, we set up obstacles in an area of high bat traffic during swarming. We used combinations of light intensities and visually dissimilar obstacles to verify that bats orient by vision. In early August, bats collided more often in the light than the dark, and probabilities of collision varied with the visibility of obstacles. However, the probabilities of collisions altered in mid to late August, coincident with the start of behavioural, hormonal, and physiological changes occurring during swarming and mating. Distress calls did not distract bats and increase the incidence of collisions. CONCLUSIONS/SIGNIFICANCE: Our findings indicate that visual cues are more important for free-flying bats than previously recognized, suggesting integration of multi-sensory modalities during orientation. Furthermore, our study highlights differences between responses of captive and wild bats, indicating a need for more field experiments.  
  Address Department of Biology, University of Western Ontario, London, Ontario, Canada. dnorbach@gmail.com  
  Corporate Author Thesis  
  Publisher Place of Publication Editor (up)  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1932-6203 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21085481; PMCID:PMC2976695 Approved no  
  Call Number IDA @ john @ Serial 96  
Permanent link to this record
 

 
Author Figueiro, M.G.; Bierman, A.; Plitnick, B.; Rea, M.S. url  doi
openurl 
  Title Preliminary evidence that both blue and red light can induce alertness at night Type Journal Article
  Year 2009 Publication BMC Neuroscience Abbreviated Journal BMC Neurosci  
  Volume 10 Issue Pages 105  
  Keywords Adult; Alpha Rhythm; Analysis of Variance; Beta Rhythm; Circadian Rhythm/*physiology; Cornea/physiology; Dose-Response Relationship, Radiation; Electrocardiography; Female; Humans; *Light; Male; Melatonin/secretion; Middle Aged; *Photic Stimulation; Psychomotor Performance; Radioimmunoassay; Salivary Glands/secretion; Wakefulness/*physiology; physiology of vision; blue light; red light  
  Abstract BACKGROUND: A variety of studies have demonstrated that retinal light exposure can increase alertness at night. It is now well accepted that the circadian system is maximally sensitive to short-wavelength (blue) light and is quite insensitive to long-wavelength (red) light. Retinal exposures to blue light at night have been recently shown to impact alertness, implicating participation by the circadian system. The present experiment was conducted to look at the impact of both blue and red light at two different levels on nocturnal alertness. Visually effective but moderate levels of red light are ineffective for stimulating the circadian system. If it were shown that a moderate level of red light impacts alertness, it would have had to occur via a pathway other than through the circadian system. METHODS: Fourteen subjects participated in a within-subject two-night study, where each participant was exposed to four experimental lighting conditions. Each night each subject was presented a high (40 lx at the cornea) and a low (10 lx at the cornea) diffuse light exposure condition of the same spectrum (blue, lambda(max) = 470 nm, or red, lambda(max) = 630 nm). The presentation order of the light levels was counterbalanced across sessions for a given subject; light spectra were counterbalanced across subjects within sessions. Prior to each lighting condition, subjects remained in the dark (< 1 lx at the cornea) for 60 minutes. Electroencephalogram (EEG) measurements, electrocardiogram (ECG), psychomotor vigilance tests (PVT), self-reports of sleepiness, and saliva samples for melatonin assays were collected at the end of each dark and light periods. RESULTS: Exposures to red and to blue light resulted in increased beta and reduced alpha power relative to preceding dark conditions. Exposures to high, but not low, levels of red and of blue light significantly increased heart rate relative to the dark condition. Performance and sleepiness ratings were not strongly affected by the lighting conditions. Only the higher level of blue light resulted in a reduction in melatonin levels relative to the other lighting conditions. CONCLUSION: These results support previous findings that alertness may be mediated by the circadian system, but it does not seem to be the only light-sensitive pathway that can affect alertness at night.  
  Address Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USA. figuem@rpi.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor (up)  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1471-2202 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:19712442; PMCID:PMC2744917 Approved no  
  Call Number IDA @ john @ Serial 285  
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Author Wood, B.; Rea, M.S.; Plitnick, B.; Figueiro, M.G. url  doi
openurl 
  Title Light level and duration of exposure determine the impact of self-luminous tablets on melatonin suppression Type Journal Article
  Year 2013 Publication Applied Ergonomics Abbreviated Journal Appl Ergon  
  Volume 44 Issue 2 Pages 237-240  
  Keywords Adolescent; *Computers, Handheld; Female; Humans; Light/*adverse effects; Male; Melatonin/*biosynthesis; Photoperiod; Saliva/*metabolism; Sleep/radiation effects; Time Factors; Young Adult; melatonin  
  Abstract Exposure to light from self-luminous displays may be linked to increased risk for sleep disorders because these devices emit optical radiation at short wavelengths, close to the peak sensitivity of melatonin suppression. Thirteen participants experienced three experimental conditions in a within-subjects design to investigate the impact of self-luminous tablet displays on nocturnal melatonin suppression: 1) tablets-only set to the highest brightness, 2) tablets viewed through clear-lens goggles equipped with blue light-emitting diodes that provided 40 lux of 470-nm light at the cornea, and 3) tablets viewed through orange-tinted glasses (dark control; optical radiation <525 nm approximately 0). Melatonin suppressions after 1-h and 2-h exposures to tablets viewed with the blue light were significantly greater than zero. Suppression levels after 1-h exposure to the tablets-only were not statistically different than zero; however, this difference reached significance after 2 h. Based on these results, display manufacturers can determine how their products will affect melatonin levels and use model predictions to tune the spectral power distribution of self-luminous devices to increase or to decrease stimulation to the circadian system.  
  Address Lighting Research Center, Rensselaer Polytechnic Institute, 21 Union Street, Troy, NY 12180, USA. woodb5@rpi.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor (up)  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-6870 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:22850476 Approved no  
  Call Number IDA @ john @ Serial 136  
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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  
  Publisher Place of Publication Editor (up)  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-972X ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21193540; PMCID:PMC3047226 Approved no  
  Call Number IDA @ john @ Serial 139  
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