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Author Blagonravov, M.L.; Bryk, A.A.; Medvedeva, E.V.; Goryachev, V.A.; Chibisov, S.M.; Kurlaeva, A.O.; Agafonov, E.D. url  doi
openurl 
  Title Structure of Rhythms of Blood Pressure, Heart Rate, Excretion of Electrolytes, and Secretion of Melatonin in Normotensive and Spontaneously Hypertensive Rats Maintained under Conditions of Prolonged Daylight Duration Type Journal Article
  Year 2019 Publication Bulletin of Experimental Biology and Medicine Abbreviated Journal Bull Exp Biol Med  
  Volume 168 Issue 1 Pages 18-23  
  Keywords Animals; arterial hypertension; biological rhythms; excessive exposure to light; melatonin  
  Abstract We studied the structure of rhythms of BP, HR (by telemetric monitoring), electrolyte excretion (by capillary electrophoresis), and products of epiphyseal melatonin (by the urinary concentration of 6-sulfatoxymelatonin measured by ELISA) in normotensive Wistar-Kyoto rats and spontaneously hypertensive SHR rats maintained at 16/8 h and 20/4 h light-dark regimes. In Wister-Kyoto rats exposed to prolonged daylight, we observed changes in the amplitude, rhythm power (% of rhythm), and range of oscillations of systolic BP; HR mezor decreased. In SHR rats, mezor of HR also decreased, but other parameters of rhythms remained unchanged. Changes in electrolyte excretion were opposite in normo- and hypertensive rats. Under conditions of 20/4 h light-dark regime, daytime melatonin production tended to increase in normotensive rats and significantly increased in SHR rats. At the same time, nighttime melatonin production did not change in both normotensive and hypertensive animals. As the secretion of melatonin has similar features in animals of both lines, we can say that the epiphyseal component of the “biological clock” is not the only component of the functional system that determines the response of the studied rhythms to an increase in the duration of light exposure.  
  Address V. A. Frolov Department of General Pathology and Pathophysiology, Institute for Medicine, Peoples' Friendship University of Russia, Moscow, Russia  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0007-4888 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:31741240 Approved no  
  Call Number GFZ @ kyba @ Serial (down) 2755  
Permanent link to this record
 

 
Author Phillips, A.J.K.; Vidafar, P.; Burns, A.C.; McGlashan, E.M.; Anderson, C.; Rajaratnam, S.M.W.; Lockley, S.W.; Cain, S.W. url  doi
openurl 
  Title High sensitivity and interindividual variability in the response of the human circadian system to evening light Type Journal Article
  Year 2019 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc Natl Acad Sci U S A  
  Volume 116 Issue 24 Pages 12019-12024  
  Keywords Human Health; circadian rhythms; light sensitivity; circadian disruption; melatonin suppression; evening light  
  Abstract Before the invention of electric lighting, humans were primarily exposed to intense (>300 lux) or dim (<30 lux) environmental light-stimuli at extreme ends of the circadian system's dose-response curve to light. Today, humans spend hours per day exposed to intermediate light intensities (30-300 lux), particularly in the evening. Interindividual differences in sensitivity to evening light in this intensity range could therefore represent a source of vulnerability to circadian disruption by modern lighting. We characterized individual-level dose-response curves to light-induced melatonin suppression using a within-subjects protocol. Fifty-five participants (aged 18-30) were exposed to a dim control (<1 lux) and a range of experimental light levels (10-2,000 lux for 5 h) in the evening. Melatonin suppression was determined for each light level, and the effective dose for 50% suppression (ED50) was computed at individual and group levels. The group-level fitted ED50 was 24.60 lux, indicating that the circadian system is highly sensitive to evening light at typical indoor levels. Light intensities of 10, 30, and 50 lux resulted in later apparent melatonin onsets by 22, 77, and 109 min, respectively. Individual-level ED50 values ranged by over an order of magnitude (6 lux in the most sensitive individual, 350 lux in the least sensitive individual), with a 26% coefficient of variation. These findings demonstrate that the same evening-light environment is registered by the circadian system very differently between individuals. This interindividual variability may be an important factor for determining the circadian clock's role in human health and disease.  
  Address Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia sean.cain@monash.edu  
  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 0027-8424 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:31138694 Approved no  
  Call Number IDA @ intern @ Serial (down) 2521  
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Author Wams, E.J.; Woelders, T.; Marring, I.; van Rosmalen, L.; Beersma, D.G.M.; Gordijn, M.C.M.; Hut, R.A. url  doi
openurl 
  Title Linking Light Exposure and Subsequent Sleep: A Field Polysomnography Study in Humans Type Journal Article
  Year 2017 Publication Sleep Abbreviated Journal Sleep  
  Volume 40 Issue 12 Pages  
  Keywords actigraphy; chronobiology; circadian rhythms; scoring; sleep/wake mechanisms  
  Abstract Study objectives: To determine the effect of light exposure on subsequent sleep characteristics under ambulatory field conditions. Methods: Twenty healthy participants were fitted with ambulatory polysomnography (PSG) and wrist-actigraphs to assess light exposure, rest-activity, sleep quality, timing, and architecture. Laboratory salivary dim-light melatonin onset was analyzed to determine endogenous circadian phase. Results: Later circadian clock phase was associated with lower intensity (R2 = 0.34, chi2(1) = 7.19, p < .01), later light exposure (quadratic, controlling for daylength, R2 = 0.47, chi2(3) = 32.38, p < .0001), and to later sleep timing (R2 = 0.71, chi2(1) = 20.39, p < .0001). Those with later first exposure to more than 10 lux of light had more awakenings during subsequent sleep (controlled for daylength, R2 = 0.36, chi2(2) = 8.66, p < .05). Those with later light exposure subsequently had a shorter latency to first rapid eye movement (REM) sleep episode (R2 = 0.21, chi2(1) = 5.77, p < .05). Those with less light exposure subsequently had a higher percentage of REM sleep (R2 = 0.43, chi2(2) = 13.90, p < .001) in a clock phase modulated manner. Slow-wave sleep accumulation was observed to be larger after preceding exposure to high maximal intensity and early first light exposure (p < .05). Conclusions: The quality and architecture of sleep is associated with preceding light exposure. We propose that light exposure timing and intensity do not only modulate circadian-driven aspects of sleep but also homeostatic sleep pressure. These novel ambulatory PSG findings are the first to highlight the direct relationship between light and subsequent sleep, combining knowledge of homeostatic and circadian regulation of sleep by light. Upon confirmation by interventional studies, this hypothesis could change current understanding of sleep regulation and its relationship to prior light exposure. Clinical trial details: This study was not a clinical trial. The study was ethically approved and nationally registered (NL48468.042.14).  
  Address Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, The Netherlands  
  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 0161-8105 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:29040758; PMCID:PMC5806586 Approved no  
  Call Number GFZ @ kyba @ Serial (down) 1885  
Permanent link to this record
 

 
Author Qian, J.; Scheer, F.A.J.L. url  doi
openurl 
  Title Circadian System and Glucose Metabolism: Implications for Physiology and Disease Type Journal Article
  Year 2016 Publication Trends in Endocrinology and Metabolism: TEM Abbreviated Journal Trends Endocrinol Metab  
  Volume 27 Issue 5 Pages 282-293  
  Keywords Human Health; circadian rhythms; food timing; glucose metabolism; melatonin; sleep; type 2 diabetes  
  Abstract The circadian system serves one of the most fundamental properties present in nearly all organisms: it generates 24-h rhythms in behavioral and physiological processes and enables anticipating and adapting to daily environmental changes. Recent studies indicate that the circadian system is important in regulating the daily rhythm in glucose metabolism. Disturbance of this circadian control or of its coordination relative to the environmental/behavioral cycle, such as in shift work, eating late, or due to genetic changes, results in disturbed glucose control and increased type 2 diabetes risk. Therefore, an in-depth understanding of the mechanisms underlying glucose regulation by the circadian system and its disturbance may help in the development of therapeutic interventions against the deleterious health consequences of circadian disruption.  
  Address Medical Chronobiology Program, Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, MA 02115, USA; Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115, USA; fscheer(at)bwh.harvard.edu  
  Corporate Author Thesis  
  Publisher Cell Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1043-2760 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:27079518; PMCID:PMC4842150 Approved no  
  Call Number IDA @ john @ Serial (down) 1446  
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Author Cornean, R.E.; Margescu, M.; Simionescu, B. url  openurl
  Title Disruption of the Cyrcadian System and Obesity Type Journal Article
  Year 2015 Publication Jurnalul Pediatrului Abbreviated Journal Jurnalul Pediatrului  
  Volume XVIII Issue Supplement 3 Pages 38-42  
  Keywords Human Health; sleep deprivation; circadian rhythms; *Chronobiology Disorders; chronodisruption; obesity  
  Abstract Disruption of the cyrcadian system is a relatively new concept incriminated as being responsible for obesity, cardiovascular involvement, cognitive impairment, premature aging and last but not least, cancer. Because obesity is undoubtedly assimilated today to the medical conditions related to the disruption of the normal chronobiology, this paper presents the pivotal role of chronodisruption in the neuroendocrine control of appetite among these patients.  
  Address University of Medicine and Pharmacy "Iuliu Hatieganu” Cluj – Napoca, Romania; recornean(as)yahoo.com  
  Corporate Author Thesis  
  Publisher Romanian Society of Pediatric Surgery Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2065-4855 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial (down) 1349  
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