Chamorro, E., Bonnin-Arias, C., Perez-Carrasco, M. J., Munoz de Luna, J., Vazquez, D., & Sanchez-Ramos, C. (2013). Effects of light-emitting diode radiations on human retinal pigment epithelial cells in vitro. Photochem Photobiol, 89(2), 468–473.
Abstract: Human visual system is exposed to high levels of natural and artificial lights of different spectra and intensities along lifetime. Light-emitting diodes (LEDs) are the basic lighting components in screens of PCs, phones and TV sets; hence it is so important to know the implications of LED radiations on the human visual system. The aim of this study was to investigate the effect of LEDs radiations on human retinal pigment epithelial cells (HRPEpiC). They were exposed to three light-darkness (12 h/12 h) cycles, using blue-468 nm, green-525 nm, red-616 nm and white light. Cellular viability of HRPEpiC was evaluated by labeling all nuclei with DAPI; Production of reactive oxygen species (ROS) was determined by H2DCFDA staining; mitochondrial membrane potential was quantified by TMRM staining; DNA damage was determined by H2AX histone activation, and apoptosis was evaluated by caspases-3,-7 activation. It is shown that LED radiations decrease 75-99% cellular viability, and increase 66-89% cellular apoptosis. They also increase ROS production and DNA damage. Fluorescence intensity of apoptosis was 3.7% in nonirradiated cells and 88.8%, 86.1%, 83.9% and 65.5% in cells exposed to white, blue, green or red light, respectively. This study indicates three light-darkness (12 h/12 h) cycles of exposure to LED lighting affect in vitro HRPEpiC.
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Oesch-Bartlomowicz, B., Weiss, C., Dietrich, C., & Oesch, F. (2009). Circadian rhythms and chemical carcinogenesis: Potential link. An overview. Mutat Res, 680(1-2), 83–86.
Abstract: Circadian rhythm is an integral and not replaceable part of the organism's homeostasis. Its signalling is multidimensional, overlooking global networks such as chromatin remodelling, cell cycle, DNA damage and repair as well as nuclear receptors function. Understanding its global networking will allow us to follow up not only organism dysfunction and pathology (including chemical carcinogenesis) but well-being in general having in mind that time is not always on our side.
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Stevens, R. G., Brainard, G. C., Blask, D. E., Lockley, S. W., & Motta, M. E. (2013). Adverse health effects of nighttime lighting: comments on American Medical Association policy statement. Am J Prev Med, 45(3), 343–346.
Abstract: The American Medical Association House of Delegates in June of 2012 adopted a policy statement on nighttime lighting and human health. This major policy statement summarizes the scientific evidence that nighttime electric light can disrupt circadian rhythms in humans and documents the rapidly advancing understanding from basic science of how disruption of circadian rhythmicity affects aspects of physiology with direct links to human health, such as cell cycle regulation, DNA damage response, and metabolism. The human evidence is also accumulating, with the strongest epidemiologic support for a link of circadian disruption from light at night to breast cancer. There are practical implications of the basic and epidemiologic science in the form of advancing lighting technologies that better accommodate human circadian rhythmicity.
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