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Author Ashkenazi, I. E.; Reinberg, A,; Bicakova-Rocher, A.; Ticher, A. url  openurl
  Title The genetic background of individual variations of circadian-rhythm periods in healthy human adults. Type Journal Article
  Year 1993 Publication American Journal of Human Genetics Abbreviated Journal  
  Volume 52 Issue 6 Pages 1250–1259  
  Keywords Human Health; Adult; Body Temperature; Bronchi; Bronchi: physiology; Circadian Rhythm; Circadian Rhythm: genetics; Female; Genetic Variation; Hand; Hand: physiology; Heart Rate; Humans; Male; Middle Aged; Sex Factors; Sleep  
  Abstract As a group phenomenon, human variables exhibit a rhythm with a period (tau) equal to 24 h. However, healthy human adults may differ from one another with regard to the persistence of the 24-h periods of a set of variables' rhythms within a given individual. Such an internal desynchronization (or individual circadian dyschronism) was documented during isolation experiments without time cues, both in the present study involving 78 male shift workers and in 20 males and 19 females living in a natural setting. Circadian rhythms of sleep-wake cycles, oral temperature, grip strength of both hands, and heart rate were recorded, and power-spectra analyses of individual time series of about 15 days were used to quantify the rhythm period of each variable. The period of the sleep-wake cycle seldom differed from 24 h, while rhythm periods of the other variables exhibited a trimodal distribution (tau = 24 h, tau > 24 h, tau < 24 h). Among the temperature rhythm periods which were either < 24 h or > 24 h, none was detected between 23.2 and 24 h or between 24 and 24.8 h. Furthermore, the deviations from the 24-h period were predominantly grouped in multiples of +/- 0.8 h. Similar results were obtained when the rhythm periods of hand grip strength were analyzed (for each hand separately). In addition, the distribution of grip strength rhythm periods of the left hand exhibited a gender-related difference. These results suggested the presence of genetically controlled variability. Consequently, the distribution pattern of the periods was analyzed to elucidate its compatibility with a genetic control consisting of either a two-allele system, a multiple-allele system, or a polygenic system. The analysis resulted in structuring a model which integrates the function of a constitutive (essential) gene which produces the exact 24-h period (the Dian domain) with a set of (inducible) polygenes, the alleles of which, contribute identical time entities to the period. The time entities which affected the rhythm periods of the variables examined were in the magnitude of +/- 0.8 h. Such an assembly of genes may create periods ranging from 20 to 28 h (the Circadian domain). The model was termed by us “The Dian-Circadian Model.” This model can also be used to explain the beat phenomena in biological rhythms, the presence of 7-d and 30-d periods, and interindividual differences in sensitivity of rhythm characteristics (phase shifts, synchronization, etc.) to external (and environmental) factors.  
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  Call Number LoNNe @ schroer @ Serial 582  
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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  
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  ISSN (up) 0003-6870 ISBN Medium  
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  Notes PMID:22850476 Approved no  
  Call Number IDA @ john @ Serial 136  
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Author Fritschi, L.; Erren, T.C.; Glass, D.C.; Girschik, J.; Thomson, A.K.; Saunders, C.; Boyle, T.; El-Zaemey, S.; Rogers, P.; Peters, S.; Slevin, T.; D'Orsogna, A.; de Vocht, F.; Vermeulen, R.; Heyworth, J.S. url  doi
openurl 
  Title The association between different night shiftwork factors and breast cancer: a case-control study Type Journal Article
  Year 2013 Publication British Journal of Cancer Abbreviated Journal Br J Cancer  
  Volume 109 Issue 9 Pages 2472-2480  
  Keywords Adult; Aged; Aged, 80 and over; Breast Neoplasms/*epidemiology/etiology; Case-Control Studies; Female; Humans; Life Style; Middle Aged; Questionnaires; Risk; Risk Factors; Western Australia/epidemiology; *Work Schedule Tolerance; Young Adult; oncogenesis  
  Abstract BACKGROUND: Research on the possible association between shiftwork and breast cancer is complicated because there are many different shiftwork factors, which might be involved including: light at night, phase shift, sleep disruption and changes in lifestyle factors while on shiftwork (diet, physical activity, alcohol intake and low sun exposure). METHODS: We conducted a population-based case-control study in Western Australia from 2009 to 2011 with 1205 incident breast cancer cases and 1789 frequency age-matched controls. A self-administered questionnaire was used to collect demographic, reproductive, and lifestyle factors and lifetime occupational history and a telephone interview was used to obtain further details about the shiftwork factors listed above. RESULTS: A small increase in risk was suggested for those ever doing the graveyard shift (work between midnight and 0500 hours) and breast cancer (odds ratio (OR)=1.16, 95% confidence interval (CI)=0.97-1.39). For phase shift, we found a 22% increase in breast cancer risk (OR=1.22, 95% CI=1.01-1.47) with a statistically significant dose-response relationship (P=0.04). For the other shiftwork factors, risks were marginally elevated and not statistically significant. CONCLUSION: We found some evidence that some of the factors involved in shiftwork may be associated with breast cancer but the ORs were low and there were inconsistencies in duration and dose-response relationships.  
  Address Western Australian Institute for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia  
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  ISSN (up) 0007-0920 ISBN Medium  
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  Notes PMID:24022188; PMCID:PMC3817316 Approved no  
  Call Number IDA @ john @ Serial 153  
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Author Schmoll, C.; Khan, A.; Aspinall, P.; Goudie, C.; Koay, P.; Tendo, C.; Cameron, J.; Roe, J.; Deary, I.; Dhillon, B. url  doi
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  Title New light for old eyes: comparing melanopsin-mediated non-visual benefits of blue-light and UV-blocking intraocular lenses Type
  Year 2014 Publication The British Journal of Ophthalmology Abbreviated Journal Br J Ophthalmol  
  Volume 98 Issue 1 Pages 124-128  
  Keywords Aged; Cataract/*physiopathology; Circadian Rhythm/physiology; Cognition/*physiology; Female; Humans; Lens Implantation, Intraocular; *Lenses, Intraocular; Light; Male; Phacoemulsification; Prospective Studies; Questionnaires; Reaction Time/physiology; Regression Analysis; Rod Opsins/*physiology; Sleep/*physiology; Physiology; Retina; blue blocker; blue light  
  Abstract BACKGROUND/AIMS: Melanopsin-expressing photosensitive retinal ganglion cells form a blue-light-sensitive non-visual system mediating diverse physiological effects including circadian entrainment and cognitive alertness. Reduced blue wavelength retinal illumination through cataract formation is thought to blunt these responses while cataract surgery and intraocular lens (IOL) implantation have been shown to have beneficial effects on sleep and cognition. We aimed to use the reaction time (RT) task and the Epworth Sleepiness Score (ESS) as a validated objective platform to compare non-visual benefits of UV- and blue-blocking IOLs. METHODS: Patients were prospectively randomised to receive either a UV- or blue-blocking IOL, performing an RT test and ESS questionnaire before and after surgery. Optical blurring at the second test controlled for visual improvement. Non-operative age-matched controls were recruited for comparison. RESULTS: 80 participants completed the study. Those undergoing first-eye phacoemulsification demonstrated significant improvements in RT over control (p=0.001) and second-eye surgery patients (p=0.03). Moreover, reduced daytime sleepiness was measured by ESS for the first-eye surgery group (p=0.008) but not for the second-eye group (p=0.09). Choice of UV- or blue-blocking IOL made no significant difference to magnitude of cognitive improvement (p=0.272). CONCLUSIONS: Phacoemulsification, particularly first-eye surgery, has a strong positive effect on cognition and daytime alertness, regardless of IOL type.  
  Address Princess Alexandra Eye Hospital, , Edinburgh, UK  
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  ISSN (up) 0007-1161 ISBN Medium  
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  Notes PMID:24158845 Approved no  
  Call Number IDA @ john @ Serial 342  
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Author Blask, D.E.; Brainard, G.C.; Dauchy, R.T.; Hanifin, J.P.; Davidson, L.K.; Krause, J.A.; Sauer, L.A.; Rivera-Bermudez, M.A.; Dubocovich, M.L.; Jasser, S.A.; Lynch, D.T.; Rollag, M.D.; Zalatan, F. url  doi
openurl 
  Title Melatonin-depleted blood from premenopausal women exposed to light at night stimulates growth of human breast cancer xenografts in nude rats Type Journal Article
  Year 2005 Publication Cancer Research Abbreviated Journal Cancer Res  
  Volume 65 Issue 23 Pages 11174-11184  
  Keywords Human Health; Animals; Breast Neoplasms/*blood/genetics/pathology; Cell Growth Processes/physiology; Circadian Rhythm/*physiology; Female; Humans; Light; Liver Neoplasms, Experimental/metabolism; Male; Melatonin/blood/*deficiency; Premenopause/blood; RNA, Messenger/biosynthesis/genetics; Rats; Rats, Nude; Receptors, Melatonin/biosynthesis/genetics; Transplantation, Heterologous  
  Abstract The increased breast cancer risk in female night shift workers has been postulated to result from the suppression of pineal melatonin production by exposure to light at night. Exposure of rats bearing rat hepatomas or human breast cancer xenografts to increasing intensities of white fluorescent light during each 12-hour dark phase (0-345 microW/cm2) resulted in a dose-dependent suppression of nocturnal melatonin blood levels and a stimulation of tumor growth and linoleic acid uptake/metabolism to the mitogenic molecule 13-hydroxyoctadecadienoic acid. Venous blood samples were collected from healthy, premenopausal female volunteers during either the daytime, nighttime, or nighttime following 90 minutes of ocular bright, white fluorescent light exposure at 580 microW/cm2 (i.e., 2,800 lx). Compared with tumors perfused with daytime-collected melatonin-deficient blood, human breast cancer xenografts and rat hepatomas perfused in situ, with nocturnal, physiologically melatonin-rich blood collected during the night, exhibited markedly suppressed proliferative activity and linoleic acid uptake/metabolism. Tumors perfused with melatonin-deficient blood collected following ocular exposure to light at night exhibited the daytime pattern of high tumor proliferative activity. These results are the first to show that the tumor growth response to exposure to light during darkness is intensity dependent and that the human nocturnal, circadian melatonin signal not only inhibits human breast cancer growth but that this effect is extinguished by short-term ocular exposure to bright, white light at night. These mechanistic studies are the first to provide a rational biological explanation for the increased breast cancer risk in female night shift workers.  
  Address Laboratory of Chrono-Neuroendocrine Oncology, Bassett Research Institute, The Mary Imogene Bassett Hospital, Cooperstown, New York 13326, USA. david.blask@bassett.org  
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  ISSN (up) 0008-5472 ISBN Medium  
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  Notes PMID:16322268 Approved no  
  Call Number LoNNe @ kagoburian @ Serial 721  
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