toggle visibility Search & Display Options

Select All    Deselect All
 |   | 
Details
   print
  Records Links
Author Wu, J.; Dauchy, R.T.; Tirrell, P.C.; Wu, S.S.; Lynch, D.T.; Jitawatanarat, P.; Burrington, C.M.; Dauchy, E.M.; Blask, D.E.; Greene, M.W. url  doi
openurl 
  Title Light at Night Activates IGF-1R/PDK1 Signaling and Accelerates Tumor Growth in Human Breast Cancer Xenografts Type Journal Article
  Year 2011 Publication Cancer Research Abbreviated Journal Cancer Res  
  Volume 71 Issue 7 Pages 2622-2631  
  Keywords human health; mammals; Circadian Rhythm; nude rats  
  Abstract Regulation of diurnal and circadian rhythms and cell proliferation are coupled in all mammals, including humans. However, the molecular mechanisms by which diurnal and circadian rhythms regulate cell proliferation are relatively poorly understood. In this study, we report that tumor growth in nude rats bearing human steroid receptor-negative MCF-7 breast tumors can be significantly accelerated by exposing the rats to light at night (LAN). Under normal conditions of an alternating light/dark cycle, proliferating cell nuclear antigen (PCNA) levels in tumors were maximal in the early light phase but remained at very low levels throughout the daily 24-hour cycle period monitored. Surprisingly, PCNA was expressed in tumors continually at a high level throughout the entire 24-hour period in LAN-exposed nude rats. Daily fluctuations of Akt and mitogen activated protein kinase activation in tumors were also disrupted by LAN. These fluctuations did not track with PCNA changes, but we found that activation of the Akt stimulatory kinase phosphoinositide-dependent protein kinase 1 (PDK1) directly correlated with PCNA levels. Expression of insulin-like growth factor 1 receptor (IGF-1R), an upstream signaling molecule for PDK1, also correlated with fluctuations of PDK1/PCNA in the LAN group. In addition, circulating IGF-1 concentrations were elevated in LAN-exposed tumor-bearing nude rats. Finally, RNAi-mediated knockdown of PDK1 led to a reduction in PCNA expression and cell proliferation in vitro and tumor growth in vivo, indicating that PDK1 regulates breast cancer growth in a manner correlated with PCNA expression. Taken together, our findings demonstrate that LAN exposure can accelerate tumor growth in vivo, in part through continuous activation of IGF-1R/PDK1 signaling.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number LoNNe @ schroer @ Serial 1608  
Permanent link to this record
 

 
Author LeBlanc, Allana G.; Gunnell, Katie E.; Prince, Stephanie A.; Saunders, Travis J.; Barnes, Joel D.; Chaput, Jean-Philippe url  doi
openurl 
  Title The Ubiquity of the Screen: An Overview of the Risks and Benefits of Screen Time in Our Modern World Type Journal Article
  Year 2017 Publication Translational Journal of the American College of Sports Medicine Abbreviated Journal  
  Volume 2 Issue 17 Pages 104–113  
  Keywords Human Health  
  Abstract Sedentary behavior, and specifically screen-based sedentary behavior, has been a focus for health researchers, engineers, telecommunications companies, gamers, and the media for many years. In recent years, research in this area has proliferated at an exponential rate. On one side, arguments have been made that screen time is harmful to the healthy growth and development of children and youth. On the other side, modern technology has far surpassed any prediction of success and become a fixture of daily living, making life easier and providing opportunities never thought possible. Regardless, screens have become omnipresent in our society, and it is important to understand the risks and the benefits associated with their use. Excessive time spent in various sedentary behaviors can coexists in a lifestyle that includes sufficient levels of moderate- to vigorous-intensity physical activity, but research has shown that for optimal health benefits, individuals should be both physically active and limit their sedentary behaviors (especially screen time). This narrative review provides a brief history of research on sedentary behavior in the context of screen time, the evolution of screens and screen time, highlights the risks and benefits of screen-based sedentary behavior, and provides experimental evidence for reductions in habitual screen time.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number LoNNe @ kyba @ Serial 1745  
Permanent link to this record
 

 
Author Albreiki, Mohammed S. url  openurl
  Title The effects of light at night and/or melatonin on hormones, metabo- lites, appetite control, vascular function, and behavioural responses. Type Journal Article
  Year 2017 Publication University of Surrey Abbreviated Journal  
  Volume Issue Pages  
  Keywords Human Health  
  Abstract Light at night (LAN) is a major factor in disruption of SCN function, including melatonin suppression. Melatonin has been linked to a variety of biological processes such as lipid and glucose metabolism, vascular parameters, appetite, and behaviour. However, few human studies have investigated the effect of LAN and suppressed melatonin prior to and after an evening meal. The current thesis aims to investigate the impact of light at night and/or mela- tonin on hormones, metabolites, appetite, vascular function, and behaviour prior to and after an evening test meal in healthy participants. The first study investigated the effect of dim or bright light conditions on hor- mones, metabolites, appetite, vascular function and behavioural responses. Glucose tolerance and insulin sensitivity were reduced, lipid profiles altered and salivary melatonin suppressed under bright light compared to dim light conditions. Subjec- tive mood was improved and appetite scores increased in bright light. No differences were seen in vascular parameters. Although clear differences were apparent it could not be determined whether the effects were due to the light at night, the absence of melatonin or a combination of the two. The second study involved three conditions with the administration of exogenous melatonin 90 mins before the evening test meal under bright and dim light conditions compared to bright light alone with the consequent melatonin suppression. Glucose tolerance and insulin sensitivity were reduced and lipid profile altered in bright light when melatonin was suppressed compared to the two conditions with exogenous melatonin. Mood was improved and appetite increased with lower leptin levels and elevated wrist temperature with bright light and suppressed melatonin. Statistical analysis showed that the major effects were due to melatonin. These studies demonstrate a possible role for melatonin in glucose tolerance, insulin sensitivity and lipid metabolism when eating late at night which may have implications for shift-workers.  
  Address  
  Corporate Author Thesis Ph.D. thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number LoNNe @ kyba @; GFZ @ kyba @ Serial 1747  
Permanent link to this record
 

 
Author Shinobu Yasuo, Ayaka Iwamoto, Sang-il Lee, Shotaro Ochiai, Rina Hitachi, Satomi Shibata, Nobuo Uotsu, Chie Tarumizu, Sayuri Matsuoka, Mitsuhiro Furuse, Shigekazu Higuchi url  doi
openurl 
  Title L-Serine Enhances Light-Induced Circadian Phase Resetting in Mice and Humans Type Journal Article
  Year 2017 Publication Journal of Nutrition Abbreviated Journal  
  Volume 147 Issue 12 Pages 2347-2355  
  Keywords Animals; Human Health  
  Abstract Background: The circadian clock is modulated by the timing of ingestion or food composition, but the effects of specific nutrients are poorly understood.

Objective: We aimed to identify the amino acids that modulate the circadian clock and reset the light-induced circadian phase in mice and humans.

Methods: Male CBA/N mice were orally administered 1 of 20 L-amino acids, and the circadian and light-induced phase shifts of wheel-running activity were analyzed. Antagonists of several neurotransmitter pathways were injected before L-serine administration, and light-induced phase shifts were analyzed. In addition, the effect of L-serine on the light-induced phase advance was investigated in healthy male students (mean ± SD age 22.2 ± 1.8 y) by using dim-light melatonin onset (DLMO) determined by saliva samples as an index of the circadian phase.

Results: L-Serine administration enhanced light-induced phase shifts in mice (1.86-fold; P < 0.05). Both L-serine and its metabolite D-serine, a coagonist of N-methyl-D-aspartic acid (NMDA) receptors, exerted this effect, but D-serine concentrations in the hypothalamus did not increase after L-serine administration. The effect of L-serine was blocked by picrotoxin, an antagonist of &#947;-aminobutyric acid A receptors, but not by MK801, an antagonist of NMDA receptors. L-Serine administration altered the long-term expression patterns of clock genes in the suprachiasmatic nuclei. After advancing the light-dark cycle by 6 h, L-serine administration slightly accelerated re-entrainment to the shifted cycle. In humans, L-serine ingestion before bedtime induced significantly larger phase advances of DLMO after bright-light exposure during the morning (means ± SEMs—L-serine: 25.9 ± 6.6 min; placebo: 12.1 ± 7.0 min; P < 0.05).

Conclusion: These results suggest that L-serine enhances light-induced phase resetting in mice and humans, and it may be useful for treating circadian disturbances.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number LoNNe @ kyba @ Serial 1784  
Permanent link to this record
 

 
Author Kozaki, Tomoaki; Taketomi, Ryunosuke; Hidaka ,Yuki; Ida, Nagisa; Yasuda, Takeo url  doi
openurl 
  Title Preventive Effect of Morning Bluish LED Light on Light-induced Melatonin Suppression at Night Type Journal Article
  Year 2018 Publication Journal of Science and Technology in Lighting Abbreviated Journal  
  Volume 41 Issue Pages 206-210  
  Keywords Human Health  
  Abstract Bright nocturnal light has been known to suppress melatonin secretion. However, bright light exposure during daytime might reduce light-induced melatonin suppression (LIMS) at night. This study aims to evaluate the effect of high correlated color temperature LED light during daytime on LIMS. Male participants were exposed to different light conditions for 3 h in the morning (09:00â??12:00). The light conditions were dim light (<10 lx), 125 lx high correlated color temperature (CCT) LED light, and 250 lx high CCT LED light. The subjects were then exposed to bright light (white light, 300 lx) for 1.5 h at night (01:00â??02:30). Saliva samples were taken before (01:00) and after (02:30) exposure for evaluation of melatonin secretion. There were no significant differences in melatonin secretion before and after night-time light exposure on the 125 lx and 250 lx morning light conditions. Since these light intensities were almost equal to those in our previous study, the high CCT LED light might be appropriate for certain work places (e.g., hospitals and underground spaces), contributing to the reduction of our health risk and also saving energy.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number LoNNe @ kyba @ Serial 1785  
Permanent link to this record
Select All    Deselect All
 |   | 
Details
   print

Save Citations:
Export Records: