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Author Jasser, S.A.; Blask, D.E.; Brainard, G.C.
Title Light during darkness and cancer: relationships in circadian photoreception and tumor biology Type Journal Article
Year 2006 Publication (down) Cancer Causes & Control : CCC Abbreviated Journal Cancer Causes Control
Volume 17 Issue 4 Pages 515-523
Keywords Human Health; Animals; *Circadian Rhythm; *Darkness; Humans; *Light; Light Signal Transduction; Melatonin/physiology/secretion; Neoplasms/etiology/pathology/*physiopathology; Suprachiasmatic Nucleus/physiology
Abstract The relationship between circadian phototransduction and circadian-regulated processes is poorly understood. Melatonin, commonly a circadian phase marker, may play a direct role in a myriad of physiologic processes. The circadian rhythm for pineal melatonin secretion is regulated by the hypothalamic suprachiasmatic nucleus (SCN). Its neural source of light input is a unique subset of intrinsically photosensitive retinal ganglion cells expressing melanopsin, the primary circadian photopigment in rodents and primates. Action spectra of melatonin suppression by light have shown that light in the 446-477 nm range, distinct from the visual system's peak sensitivity, is optimal for stimulating the human circadian system. Breast cancer is the oncological disease entity whose relationship to circadian rhythm fluctuations has perhaps been most extensively studied. Empirical data has increasingly supported the hypothesis that higher risk of breast cancer in industrialized countries is partly due to increased exposure to light at night. Studies of tumor biology implicate melatonin as a potential mediator of this effect. Yet, causality between lifestyle factors and circadian tumor biology remains elusive and likely reflects significant variability with physiologic context. Continued rigorous empirical inquiry into the physiology and clinical implications of these habitual, integrated aspects of life is highly warranted at this time.
Address Department of Neurology, Light Research Program, Thomas Jefferson University, 1025 Walnut Street, Suite 507, Philadelphia, PA 19107, USA. samar.jasser@jefferson.edu
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0957-5243 ISBN Medium
Area Expedition Conference
Notes PMID:16596305 Approved no
Call Number LoNNe @ kagoburian @ Serial 766
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Author Moser, M.; Schaumberger, K.; Schernhammer, E.; Stevens, R.G.
Title Cancer and rhythm Type Journal Article
Year 2006 Publication (down) Cancer Causes & Control : CCC Abbreviated Journal Cancer Causes Control
Volume 17 Issue 4 Pages 483-487
Keywords Human Health; Animals; Breast Neoplasms/etiology/physiopathology/prevention & control; Chronobiology Phenomena; Chronotherapy; *Circadian Rhythm; Humans; Life Style; Melatonin/metabolism; Neoplasms/etiology/*physiopathology/prevention & control/therapy; Risk Factors
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Language English Summary Language Original Title
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ISSN 0957-5243 ISBN Medium
Area Expedition Conference
Notes PMID:16596301 Approved no
Call Number LoNNe @ kagoburian @ Serial 786
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Author Stevens, R.G.
Title Artificial lighting in the industrialized world: circadian disruption and breast cancer Type Journal Article
Year 2006 Publication (down) Cancer Causes & Control : CCC Abbreviated Journal Cancer Causes Control
Volume 17 Issue 4 Pages 501-507
Keywords Human Health; Alcohol Drinking/adverse effects; Animals; Breast Neoplasms/*etiology; Chronobiology Disorders/*etiology/physiopathology; Circadian Rhythm; Developing Countries; Female; Humans; Lighting/*adverse effects; Melatonin/metabolism; Risk Factors; Suprachiasmatic Nucleus/physiopathology
Abstract Breast cancer risk is high in industrialized societies, and increases as developing countries become more Westernized. The reasons are poorly understood. One possibility is circadian disruption from aspects of modern life, in particular the increasing use of electric power to light the night, and provide a sun-free environment during the day inside buildings. Circadian disruption could lead to alterations in melatonin production and in changing the molecular time of the circadian clock in the suprachiasmatic nuclei (SCN). There is evidence in humans that the endogenous melatonin rhythm is stronger for persons in a bright-day environment than in a dim-day environment; and the light intensity necessary to suppress melatonin at night continues to decline as new experiments are done. Melatonin suppression can increase breast tumorigenesis in experimental animals, and altering the endogenous clock mechanism may have downstream effects on cell cycle regulatory genes pertinent to breast tissue development and susceptibility. Therefore, maintenance of a solar day-aligned circadian rhythm in endogenous melatonin and in clock gene expression by exposure to a bright day and a dark night, may be a worthy goal. However, exogenous administration of melatonin in an attempt to achieve this goal may have an untoward effect given that pharmacologic dosing with melatonin has been shown to phase shift humans depending on the time of day it's given. Exogenous melatonin may therefore contribute to circadian disruption rather than alleviate it.
Address University of Connecticut Health Center, Farmington, CT 06030-6325, USA. bugs@neuron.uchc.edu
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 0957-5243 ISBN Medium
Area Expedition Conference
Notes PMID:16596303 Approved no
Call Number LoNNe @ kagoburian @ Serial 818
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Author Baker, B.J.; Richardson, J.M.L.
Title The effect of artificial light on male breeding-season behaviour in green frogs,Rana clamitans melanota Type Journal Article
Year 2006 Publication (down) Canadian Journal of Zoology Abbreviated Journal Can. J. Zool.
Volume 84 Issue 10 Pages 1528-1532
Keywords animals; amphibians; frogs; green frogs; Rana clamitans melanota; Reproduction; reproductive strategies
Abstract Artificial night lighting (or ecological light pollution) is only now gaining attention as a source of long-term effects on the ecology of both diurnal and nocturnal animals. The limited data available clearly indicate that artificial light can affect physiology and behaviour of animals, leading to ecological consequences at the population, community, and ecosystem levels. Aquatic ecosystems may be particularly vulnerable to such effects, and nocturnally breeding animals such as frogs may be especially affected. To address this potential, we quantify the effects of artificial light on calling and movement behaviour in a rural population of male green frogs (Rana clamitans melanota (Rafinesque, 1820)) during the breeding season. When exposed to artificial light, frogs produced fewer advertisement calls and moved more frequently than under ambient light conditions. Results clearly demonstrate that male green frog behaviour is affected by the presence of artificial light in a manner that has the potential to reduce recruitment rates and thus affect population dynamics.
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ISSN 0008-4301 ISBN Medium
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Notes Approved no
Call Number IDA @ john @ Serial 71
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Author Raven, J.A.; Cockell, C.S.
Title Influence on photosynthesis of starlight, moonlight, planetlight, and light pollution (reflections on photosynthetically active radiation in the universe) Type Journal Article
Year 2006 Publication (down) Astrobiology Abbreviated Journal Astrobiology
Volume 6 Issue 4 Pages 668-675
Keywords Plants
Abstract Photosynthesis on Earth can occur in a diversity of organisms in the photosynthetically active radiation (PAR) range of 10 nmol of photons m(-2) s(-1) to 8 mmol of photons m(-2) s(-1). Similar considerations would probably apply to photosynthetic organisms on Earth-like planets (ELPs) in the continuously habitable zone of other stars. On Earth, starlight PAR is inadequate for photosynthetically supported growth. An increase in starlight even to reach the minimum theoretical levels to allow for photosynthesis would require a universe that was approximately ten million times older, or with a ten million times greater density of stars, than is the case for the present universe. Photosynthesis on an ELP using PAR reflected from a natural satellite with the same size as our Moon, but at the Roche limit, could support a low rate of photosynthesis at full Moon. Photosynthesis on an ELP-like satellite of a Jupiter-sized planet using light reflected from the planet could be almost 1% of the rate in full sunlight on Earth when the planet was full. These potential contributions to photosynthesis require that the contribution is compared with the rate of photosynthesis driven by direct radiation from the star. Light pollution on Earth only energizes photosynthesis by organisms that are very close to the light source. However, effects of light pollution on photosynthesis can be more widespread if the photosynthetic canopy is retained for more of the year, caused by effects on photoperiodism, with implications for the influence of civilizations on photosynthesis.
Address Plant Research Unit, University of Dundee at SCRI, Scottish Crop Research Institute, Invergowrie, Dundee, United Kingdom
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1557-8070 ISBN Medium
Area Expedition Conference
Notes PMID:16916290 Approved no
Call Number LoNNe @ christopher.kyba @ Serial 1198
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