Light Pollution as a New Risk Factor for Human Breast and Prostate Cancers
Abstract
Humans are diurnal organisms whose biological clock and temporal organization depend on natural light/dark cycles. Changes in the photoperiod are a signal for seasonal acclimatization of physiological and immune systems as well as behavioral patterns. The invention of electrical light bulbs created more opportunities for work and leisure. However, exposure to artificial light at night (LAN) affects our biological clock, and suppresses pineal melatonin (MLT) production. Among its other properties, MLT is an antioncogenic agent, and therefore its suppression increases the risks of developing breast and prostate cancers (BC&PC). To the best of our knowledge, this book is the first to address the linkage between light pollution and BC&PC in humans. It explains several state-of-the-art theories, linking light pollution with BC&PC. It also illustrates research hypotheses about health effects of light pollution using the results of animal models and population-based studies. © Springer Science+Business Media Dordrecht 2013. All rights are reserved.
Chapters (14)
Light is a small part of the electromagnetic spectrum, from violet to red, to which our eyes are responsive. Photometry measures light using several units, including the candela for intensity, the lumen for flux, the lux for illuminance and the candela per square metre for luminance. Vision at relatively high illumination levels is called photopic, when our eyes mainly use cones; in the dark, vision is called scotopic. Recently, a non-visual photoreceptor with peak sensitivity in the blue part of the spectrum has been discovered which regulates our circadian rhythms.
Different living organisms are active at different times of the 24-h cycle. Results of controlled experiments revealed that living organisms anticipate the time of activity due to the existence of an endogenous biological clock entrained by the exogenous environmental Zeitgeber. Our daily rhythms can thus be described as an orchestra in which the harmony of all instruments is maintained by the single conductor, with our biological clock carrying out such a function. The biological clock also works as a calendar helping living organisms to anticipate seasonal changes and to acclimatize their physiological systems and behavioral patterns to the approaching season. For its temporal organization, the biological clock uses the signals of light intensity detected by eyes, as well as signals of different wavelength.
As we know today, our biological master clock is located in the supperachiasmatic nuclei (SCN) of the hypothalamus and is entrained mainly by light/dark (L/D) cycles; it also acts as our internal calendar. The modus operandi of our biological clock was considered, for many years, as a black box. Our understanding of the biological clock functioning came from experiments in which subjects were exposed to light during the subjective night, which resulted in a phase shift, while such a shift was not detected when exposure to light took place during the subjective day. As we also know today, the molecular basis of the biological clock is based on interactions between various clock genes paired to create hetero-dimmers and are templates for proteins production that interact with genes by positive and negative feedback loops.
Light/dark (L/D) cycles are the environmental cue for the entrainment of our circadian rhythms while changes in photoperiod are an important environmental cue for seasonal acclimatization of different physiological systems as well as for immune system functioning. The neuro-hormone melatonin (MLT) plays a major role in this process as it indicates the dark period of the 24 h cycle. Therefore the disruption of MLT secretion due to Light at Night (LAN) exposure may have a negative impact on daily rhythms and seasonality of our physiological and immune systems. Supposedly the suppression of pineal MLT production has a direct effect on cells which contain MLT receptors.
The pineal neuro-hormone Melatonin (MLT) is involved in the regulation and functioning of various processes in the human body. Among other functions it plays a significant role in the transferring of the dark period signal on a daily basis while its levels and duration of its secretion are the basis for seasonality. As a result the suppression of MLT production by LAN exposure affects not only various daily rhythms but also seasonality of our thermoregulatory system being responsible for heat production on the one hand for heat dissipation on the other. The disruption of the MLT production also affects our immune system due to the fact that receptors of this hormone are distributed on white blood cell. Because MLT is an anti-oxidant and anti-oncogenic agent its reduction from exposure to LAN can result in increased breast prostate cancer (BC&PC) risks through a more rapid proliferation of cancerous cells or/and in an indirect way by a mal-functioning of the immune system. As MLT suppression depends not only on light intensity but also on light wavelength with short wavelength illumination being very effective in MLT suppression. The increase of such illumination worldwide under the “environmentally friendly illumination” paradigm should thus become a concern for health authorities worldwide.
People knew about electricity for centuries. However the first successful attempt to use electricity for lighting can be credited to Sir Humphrey Davy who discovered in 1801 the incandescence of an energized conductor. Yet the idea of using electricity for lighting “took off” only after the American inventor Thomas Alva Edison developed his deep vacuum incandescent lamp with a carbon cotton filament. Thomas Alva Edison also contributed to the practical use of electricity by installing the first electrical lightning system at Pearl Street in NYC in 1882. Since then both light bulbs electricity production have become relatively cheap and more reliable. As a result of rapid electricity proliferation electric lighting has substituted most traditional lighting sources making human population virtually independent of natural L/D cycles. The full range of implications of this transition for human health are yet to be determined.
Whereas light pollution is well defined by the astronomers, no biological definition of this phenomenon has been given so far. In giving such a definition, various variables of nighttime illumination, such as intensity, wavelength, duration of exposure, frequency of exposure and timing within the dark period, should be considered. A critical point is that light pollution suppresses MLT production and disrupts daily rhythms entrained by photoperiod and thus initiates a stress response, all of which are biological consequences of exposure to LAN.
The suppression of MLT by exposure to Light at Night (LAN) and its effects on daily rhythms are well documented in the literature. Throughout the years of research it has been noted that MLT treatment could not compensate for all the effects of LAN exposure and, therefore, we can conclude that other responses may result from the exposure to LAN. The idea that LAN is a general stressor was tested in the social vole Microtus socialis and an increase in adrenaline and cortisol production was detected. Recently it was also shown that LAN increases the expression of the gene hsp70 and the protein HSP70 in the brain and liver of golden spiny mice Acomys russatus, with the response levels in both tissues decreasing with the duration of acclimation. However, in the same animals, the response of the cardiocytes increased with the duration of acclimation thus indicating that different tissues respond to LAN in different ways. The fact that MLT treatment attenuates the response to LAN points to the fact that MLT may reduce negative impacts of LAN as a general stressor.
The ongoing increase in light pollution and, mainly, that of short wavelength light emission, results not only in the human pineal MLT suppression, but also affects that of animals in their “natural” ecosystems. It also affects animals’ daily rhythms, seasonality and behavioral patterns such as foraging (aerial, aquatic, and terrestrial) due to changes in the distribution patterns of their prey. The disruption of navigation by animals, such as young sea turtles’ navigation into sea-water, is also affected by urban illumination and sky glowing around cities at night. As LAN has an effect on the entrainment of our biological clock, by disrupting daily rhythms, it results in mal-functioning of the immune and physiological systems. Because these features are common to humans and animals, their similarity makes it possible to use animals for testing and developing models for sustainable nighttime illumination.
A possibility that human body may be affected by ambient light was raised, apparently for the first time, by the Israeli physician Dr. Phillip Cohen in 1970. Since then the circadian rhythm theory (CRT) has received considerable support, from both animal models and human studies. As we know today, the link between artificial light and its potential health effects may be attributed to two interdependent mechanisms—inhibition of melatonin (MLT) secretion from the pineal gland by direct exposure of human vision system to LAN and daily rhythm disruption. Although these effects are discussed in detail in separate chapters of this book, in this chapter, we review, in brief, supporting empirical evidence accumulated to date.
Geographic patterns of BC&PC worldwide are surprisingly similar, with higher rates of both cancers observed in developed countries and lower rates elsewhere. The incidence rates of these cancers are also higher in more extreme latitudes, suggesting a possibility that they are related, among other factors, to LAN, considering that in extreme latitudes artificial light is often used to compensate for a shortage of natural illumination. Our analysis supports such a possibility, especially for PC.
Due to the rapid spread of electric illumination, our world is not as dim at night as it was 130 or even 70 years ago. Nightlights of constantly increasing intensity and bluer in color, which illuminate our streets and public spaces today, are captured by satellite sensors and transmitted to the earth as digital images. In this chapter we discuss two case studies, which attempted to link the above digital maps of nighttime illumination with BC&PC incidence rates, thus helping to demonstrate a potential association between them.
Several methodological flaws may bias the results of a study of the LAN-BC&PC association. In this chapter we shall deal in brief with three such issues being in our view especially relevant to population-level studies—ecological fallacy, recall bias and eyelid effect.
In past decades, humans have effectively defeated the “nighttime darkness” by “chasing it away” from our homes, streets, highways and public-spaces, both in western countries and in many countries of the developing world. LAN has spread rapidly due to relatively easy accesses to electricity and rapidly developing infrastructures, and seems to have penetrated even the most remote corners of our Planet. Indeed, nighttime illumination today is present not only in urban areas, but also in rural communities. In addition, we commonly use today, what we call the “environmental friendly illumination,” which converts electrical energy more efficiently into short wavelength (bluer) illumination replacing more traditional incandescence bulbs, which were closer, in their spectral properties, to natural daylight.
... At the same time, a huge amount of empirical evidence has been accumulated for the adverse effects of NTL on both humans [6][7][8][9] and ecosystems [10][11][12][13]. An especially serious concern is the long-term cumulative effects of NTL, which remain almost unexplored [14]. ...
... The adverse effects of NTL are known to depend crucially on the light spectrum [21,22]. For instance, the short-wavelength light stronger suppresses melatonin production and distorts circadian rhythms in mammals [9,23,24], while the longwavelength light more strongly disrupts the magnetic orientation of migratory birds [25]. To date, the detailed spectral signatures are available for the majority of common lighting sources (see, for example, the LICA-UCM database [26]). ...
... Nowadays, LEDs' popularity is growing rapidly, mainly due to their versatility and energy-saving potential [27,28,43], and some precedents of total LED-based street lighting already exist [28,44]. At the same time, LEDs' primary emission peak,~450-460 nm [27], radically distorts circadian rhythms and suppresses melatonin production in humans, contributing to sleep disorders [45], obesity [7], hormone-dependent cancers [9], and other diseases. Thus, further analysis is needed to explore the possibility to identify LED lamps from the ISS-provided imagery. ...
Artificial night-time light (NTL), emitted by various on-ground human activities, has become intensive in many regions worldwide. Its adverse effects on human and ecosystem health crucially depend on the light spectrum, making the remote discrimination between different lamp types a highly important task. However, such studies remain extremely limited, and none of them exploit freely available satellite imagery. In the present analysis, the possibility to remotely assess the relative contribution of different lamp types into outdoor lighting is tested. For this sake, we match two data sources: (i) the radiometrically calibrated RGB image provided by the ISS (coarse spectral resolution data), and (ii) a set of in situ measurements with detailed spectral signatures conducted by ourselves (fine spectral resolution data). First, we analyze the fine spectral resolution data: using spectral signatures of standard lamp types from the LICA UCM library as endmembers, we perform an unmixing analysis upon NTL in situ measurements; by this, we obtain the estimates for relative contributions of the standard lamp types in each examined in situ measurement. Afterward, we focus on the coarse spectral resolution data: by using various types of statistical models, we predict the estimated relative contributions of each lamp type via RGB characteristics of spatially corresponding pixels of the ISS image. The built models predict sufficiently well (with R2 reaching ~0.87) the contributions of two standard lamp types: high-pressure sodium (HPS) and metal-halide (MH) lamps, the most widespread lamp types in the study area (Haifa, Israel). The restored map for HPS allocation demonstrates high concordance with the network of municipal roads, while that for MH shows notable coincidence with the industrial facilities and the airport.
... Chez l'homme, ALAN est associée à une prévalence accrue de pathologies telles que le trouble du sommeil, la dépression, l'obésité, le diabète de type 2, l'hypertriglycéridémie, les désordres affectifs, l'hypertension et la progression de certains cancers (Encadré 2) (Wyse et al., 2011;Haim and Portnov, 2013;Fonken and Nelson, 2014;Stevens and Zhu, 2015). Des conséquences écologiques sérieuses d'ALAN ont également été mises en évidence sur la flore Bennie et al., 2016Bennie et al., , 2018 (Hölker et al., 2010b;Haim and Portnov, 2013;Knop et al., 2017). ...
... Chez l'homme, ALAN est associée à une prévalence accrue de pathologies telles que le trouble du sommeil, la dépression, l'obésité, le diabète de type 2, l'hypertriglycéridémie, les désordres affectifs, l'hypertension et la progression de certains cancers (Encadré 2) (Wyse et al., 2011;Haim and Portnov, 2013;Fonken and Nelson, 2014;Stevens and Zhu, 2015). Des conséquences écologiques sérieuses d'ALAN ont également été mises en évidence sur la flore Bennie et al., 2016Bennie et al., , 2018 (Hölker et al., 2010b;Haim and Portnov, 2013;Knop et al., 2017). (Ansiau, et al.;Davis et al., 2001;Schernhammer et al., 2001;Zeitzer et al., 2011;Burgess, 2013;Haim and Portnov, 2013;Challéat, 2014;Cho et al., 2015) INTRODUCTION Au niveau écologique, des effets d'ALAN ont été démontrés sur un large éventail d'espèces végétales et animales (Davies and Smyth, 2018), cependant, je me concentrerai dans la suite de ce manuscrit uniquement sur les effets observés sur les espèces animales. ...
... Des conséquences écologiques sérieuses d'ALAN ont également été mises en évidence sur la flore Bennie et al., 2016Bennie et al., , 2018 (Hölker et al., 2010b;Haim and Portnov, 2013;Knop et al., 2017). (Ansiau, et al.;Davis et al., 2001;Schernhammer et al., 2001;Zeitzer et al., 2011;Burgess, 2013;Haim and Portnov, 2013;Challéat, 2014;Cho et al., 2015) INTRODUCTION Au niveau écologique, des effets d'ALAN ont été démontrés sur un large éventail d'espèces végétales et animales (Davies and Smyth, 2018), cependant, je me concentrerai dans la suite de ce manuscrit uniquement sur les effets observés sur les espèces animales. ...
La lumière artificielle nocturne (ALAN), reconnue comme pollution environnementale, perturbe tous les écosystèmes et affecte la photopériode, synchronisateur externe de nombreux processus biologiques. Par une approche intégrative, cette thèse a pour but d’évaluer expérimentalement l’influence d’ALAN sur le crapaud commun, Bufo bufo, amphibien nocturne couramment retrouvé en zones urbaine et péri-urbaine. Mes travaux montrent qu’en période de reproduction, ALAN réduit l’activité physique nocturne et modifie l’allocation énergétique, sans affecter ni la prise alimentaire, ni la masse corporelle des mâles. De plus, bien qu’aucun effet n’ait été observé sur la testostéronémie salivaire, ALAN affecte le comportement et le succès reproducteurs des mâles en augmentant le temps de latence pour s’accoupler avec la femelle, en diminuant le maintien de l’amplexus et en réduisant le taux de fécondation des œufs. Par ailleurs, une analyse sans a priori de transcriptomes de têtards élevés en présence d’ALAN montre une sous expression nocturne de gènes, notamment ceux impliqués dans l’immunité. Une seconde étude gène-spécifique montre une faible influence d’ALAN sur l’expression des gènes codant deux enzymes impliquées dans la synthèse de la mélatonine ou ses trois récepteurs et ne permet pas de conclure quant au rôle central de la mélatonine dans les perturbations liées à ALAN. Ainsi, cette thèse met en évidence les effets très larges d’ALAN chez le crapaud commun, affectant les processus biologiques de l’expression génique à la fitness. Ces résultats doivent être replacés dans le contexte de biologie de la conservation et pris en compte dans la préservation de l’environnement nocturne.
... Artificial night-time light (NTL), emitted by various on-ground human activities, becomes further intensive in many countries, making the world brighter (Cinzano et al., 2001;Falchi et al., 2016;Kyba et al., 2017;Zheng et al., 2021). At the same time, a huge amount of empirical evidence has been accumulated for adverse effects of NTL on both humans (Garcia-Saenz et al., 2018;Haim and Portnov, 2013;Kloog et al., 2009;McFadden et al., 2014) and ecosystems (Gaston et al., 2013;Hölker et al., 2010;Longcore et al., 2004;Owens et al., 2020). An especially serious concern comes from the long-term cumulative effects of NTL, which remains almost unexplored (Lyytimäki, 2015). ...
... The adverse effects of NTL are known to depend crucially on the light spectrum (Brainard et al., 2001;Gaston et al., 2014;Papamichael et al., 2012;Schroer et al., 2016). For instance, the shortwavelength light stronger suppresses melatonin production and distort circadian rhythms in mammals (Haim and Portnov, 2013;Hatori et al., 2017;Lockley et al., 2003), while the long-wavelength light stronger disrupts the magnetic orientation of migratory birds (Wiltschko et al., 1993). As far as adverse effects of NTL become more recognized to depend on light spectrum, multispectral satellite imagery analysis becomes more numerous (Guk and Levin, 2020;Huang et al., 2021;Levin and Duke, 2012;Rybnikova and Portnov, 2017;Zheng et al., 2018). ...
... Nowadays, LEDs' popularity grows rapidly (Alamús et al., 2017;Elvidge et al., 2010;Sánchez de Miguel et al., 2019;Schubert and Kim, 2005) mainly due to their versatility and energy saving potential, and some precedents of total LED-based street lighting already exist (Kyba et al., 2020;Sánchez de Miguel et al., 2019). At the same time, LEDs' primary emission peak, ~450-460 nm (Elvidge et al., 2010), extremely distorts circadian rhythms and suppresses melatonin production in humans, contributing to sleep disorders (Czeisler, 2013), obesity (McFadden et al., 2014), hormone-dependent cancers (Haim and Portnov, 2013), and other diseases. Thus, further analysis is needed to explore the possibility to identify LED lamps from the ISS-provided imagery. ...
Artificial night-time light (NTL), emitted by various on-ground human activities, becomes further intensive in many regions worldwide. Its adverse effects on humans’ and ecosystems’ health crucially depend on the light spectrum, making the remote discrimination between different lamps a highly important task. However, such studies remain extremely limited, and none of them exploits freely available satellite imagery. In the analysis, the possibility to remotely assess the relative contribution of different lamp types into outdoor lighting is tested. For this sake, the radiometrically calibrated ISS RGB image is used. Spatial resolution of the image is ~20 meters, implying that each pixel may represent a mixture of different lamp types. Unmixing analysis to the detailed spectral signatures of the corresponding in situ measurements is performed, with ‘pure’ lamps’ signatures as the endmembers. Afterward, statistical models to reproduce the results of unmixing based on the broad-band RGB image from the ISS are run. The built models predict well (with R2 reaching ~0.87) the contribution of high-pressure sodium (HPS) and metal-halide (MH) lamps, the most spread in the study area (Haifa, Israel). The restored map for HPS allocation demonstrates high concordance with the network of municipal roads, while that for MH shows notable coincidence with the industrial facilities and the airport.
... Recent empirical studies established significant links between artificial light-at-night (ALAN) exposure and several adverse health effects, including decreasing sleep quality and insomnia (Martin et al. 2012;Obayashi et al. 2014), increased alertness (Daurat et al. 2000;Chang et al. 2013), depression (Wallace- Guy et al. 2002;Obayashi et al. 2013), Parkinson disease (Romeo et al. 2013), overweight/obesity (Obayashi et al. 2012;McFadden et al. 2014;Rybnikova, Haim, and Portnov 2016), and elevated risk of hormone-dependent cancers, both in the general population (Haim and Portnov 2013;Hurley et al. 2014;Portnov 2015, 2016a) and in night-time shift workers (Bauer et al. 2013;Schernhammer et al. 2003). In the epidemiological literature, these links are attributed to several impact mechanisms, including the suppression of nocturnal melatonin (MLT) production, circadian disruption, attributed to night-time activities enabled by ALAN, and ALAN acting as a general stressor (Stevens and Rea 2001;Haim and Portnov 2013). ...
... Recent empirical studies established significant links between artificial light-at-night (ALAN) exposure and several adverse health effects, including decreasing sleep quality and insomnia (Martin et al. 2012;Obayashi et al. 2014), increased alertness (Daurat et al. 2000;Chang et al. 2013), depression (Wallace- Guy et al. 2002;Obayashi et al. 2013), Parkinson disease (Romeo et al. 2013), overweight/obesity (Obayashi et al. 2012;McFadden et al. 2014;Rybnikova, Haim, and Portnov 2016), and elevated risk of hormone-dependent cancers, both in the general population (Haim and Portnov 2013;Hurley et al. 2014;Portnov 2015, 2016a) and in night-time shift workers (Bauer et al. 2013;Schernhammer et al. 2003). In the epidemiological literature, these links are attributed to several impact mechanisms, including the suppression of nocturnal melatonin (MLT) production, circadian disruption, attributed to night-time activities enabled by ALAN, and ALAN acting as a general stressor (Stevens and Rea 2001;Haim and Portnov 2013). ...
... According to empirical evidence accumulated to date, exposure to ALAN may increase BC risk due to different impact mechanisms. According to the first and most thoroughly explored causality pathway, ALAN, reaching non-image forming photoreceptors in the human retina, is transferred as neural information to the pineal gland, where it suppresses MLT production, resulting, among other effects, in changing oestrogen receptor affinity and increasing susceptibility to hormone-dependent cancers, such as BC (Schernhammer and Schulmeister 2004;Blask et al. 2011;Haim and Portnov 2013). According to the second potential impact mechanism, humans, being involved in night-time activities, enabled by ALAN, may suffer from daily rhythms disruption, leading to increased susceptibility to various diseases, including BC (Stevens and Rea 2001;Navara and Nelson 2007;Haim and Portnov 2013). ...
... This make the night light available in the remote areas. Thus, population exposure to night light in both indoors and out-doors has increased substantially [26]. Unlike the regular light which had fixed and known emission spectra. ...
... The retrieval of non-image-forming photo-receptors in the retina is transferred to the pineal gland as neural information where it suppressing the melatonin secretion. Then changing in the affinity of the estrogen receptor and an increased susceptibility to hormone-dependent cancers like breast cancer [26,54]. ...
... The other possible mechanism is that human can suffer from circadian rhythms disruption by engaging in night time activities which activated by night light contributing to increased susceptibility to breast cancer [26,55]. ...
An increased risk of breast cancer has been associated with light at night (LAN). Several risk factors have been identified that play a crucial role in causing most cancers such as the consumption of alcohol and smoking, and low fruit and vegetable intake. As a risk factor for cancer, environmental factors also play an essential role including indoor and outdoor air pollution. Light pollution has been found to be a risk factor for breast cancer in the form of artificial light at night, with melatonin being the mediator between environment and the epigenome. The risk of cancer in night shift workers can also amplify by artificial light at night. Light at night may also effects sleep disruptions and also considered as a risk factor of breast cancer.
... The disruption of the day-night cycle by light pollution puts human health at risk, in accordance with clinical and epidemiological studies on humans conducted in urban settings and on night work (Haim and Portnov, 2013). Three methods have been proposed to explain how light pollution can harm human health: ...
... They are, on the contrary, most certainly linked and, in the long term, may lead to the onset of illnesses in people by upsetting the body's equilibrium. Wildlife is most likely using the same methods (Haim andPortnov, 2013, Erren andLewis, 2019). ...
... A fitting illustration of a type-VIII externality is the light pollution resulting from installing streetlights in cities. Cities install streetlights because they help improve nighttime visibility, reduce crime, and (arguably) increase transportation safety (Doleac & Sanders, 2015;Gerdes, 2013). However, streetlight-induced light pollution can have many potential direct and indirect adverse health consequences, including increase probabilities of insomnia, obesity, and conceivably even cancer, thus producing medium-to-large-scale negative externalities (Haim & Portnov, 2013). For instance, Jones (2018) finds that Los Angeles's 2009 LED streetlight efficiency program, which installed 141,089 LED streetlights in the city, led to a non-negligible increase in breast cancer mortality of 0.479 per 100,000 people. ...
... Epidemiological literature also documents that artificial lights at night disrupt the circadian rhythm, thus leading to decreases in melatonin and increasing the risk of breast cancer (Stevens, 2011). Although private citizens can adopt various measures to protect themselves from the adverse effects, such measures only work to an extent because limiting regular exposure to streetlights is difficult (Haim & Portnov, 2013). City governments could adopt other alternatives-for example, by replacing LED lights with gas lamps-but that would lead to other externalities such as increased fire risk and methane emissions. ...
This paper contributes to the literature on externalities and their classification by reconciling insights from transaction costs theory with James Buchanan’s and Elinor Ostrom’s analyses of property rights and institutional diversity. We critique the dominant Pigouvian analysis, which assumes only two forms of institutions—namely, governments and private markets—that can internalize externalities. We develop a new taxonomy of externalities that provides relevant conceptual space for a wide array of institutions that the market-versus-state dichotomy obscures. The proposed taxonomy considers two key classes of often-conflated attributes: (1) the scale of externalities, and (2) the assignability, enforceability, and tradability of property rights. This approach enriches the Coasean (transaction cost) perspective by allowing us to unbundle transaction costs in a manner that extends its applicability to nonmarket situations in which market-based transactions are either not permitted or technically infeasible. Thus, by integrating insights from two distinct Public Choice schools, we broaden the theory of externalities to not only encompass market exchanges but also to incorporate cases in which property rights are, and will remain, unclear. We conclude that institutional diversity can offer adaptable solutions to tackle medium- and large-scale externalities.
... The blue (i.e., the short wavelength) light minimizes energy waste while maintaining visual performance where low illumination levels are required [22]. However, blue light illumination is known to adversely affect circadian rhythms and melatonin secretion in animals and humans [23,24], while red (i.e., long wavelength) light has less impact on human health and At the first step, we downloaded the Dalian satellite cloud-free map from the ISS luminous image archive ( Figure 2). The downloaded image was for the year 2010, the latest image available for the study area, with the spatial resolution of~40 m per pixel. ...
... The blue (i.e., the short wavelength) light minimizes energy waste while maintaining visual performance where low illumination levels are required [22]. However, blue light illumination is known to adversely affect circadian rhythms and melatonin secretion in animals and humans [23,24], while red (i.e., long wavelength) light has less impact on human health and ecology [25,26]. Therefore, different light band images were used for the study neighborhoods' identification and analysis. ...
The perceived quality of street lighting influences pedestrians’ perceptions of safety and visual comfort, as well as outdoors activities at night. This study explores the association between street lighting attributes, such as illuminance and wavelength, and pedestrians’ feeling of safety (FoS) and perceived lighting quality (PLQ) in eight residential districts in Dalian, China. To achieve this goal, we combine remote sensing technology with ground investigation. The ground research includes physical measurements of lighting attributes, such as intensity, color temperature, and glare, as well as survey evaluations of pedestrians’ perceptions of safety and visual comfort. We also analyze the influence of several environmental factors, such as traffic volumes and vegetation, while accounting for personal characteristics of the observers, such as gender and age. Findings from the remote sensing reveal that Dalian’s residential districts differ substantially by their nighttime light emissions, with high concentration of strong red band (i.e., long wavelength) emissions occurring in Zhongshan and Jinzhou, and strong blue band (i.e., short wavelength) emissions found in central Zhongshan. Results from the ground surveys further indicate that a satisfactory level of FoS reaches at the illumination levels of 5–17 lx, and that people feel safer if nighttime light is warm and uniform. From a multiple regression analysis, it is also found that illuminance and uniformity are the main factors affecting PLQ under conditions of low or high illuminance, while glare and color temperature play a more significant role under high illuminance. In addition, a satisfactory level of PLQ is found at illuminance levels of 25–35 lx and light color temperature of 4000 K–5500 K.
... reproductive abnormality [6], deranged feeding cycle and obesity and disrupted melatonin rhythm [4,7]. Exposure to light at night has been widely recognized as an important risk factor for breast cancer and metabolic disorders, specifically diabetes mellitus [8]. Apart from the circadian consequence of light pollution, Shang et al. (2014) [9] showed that exposure of Sprague Dawley rats to blue light resulted in apoptosis and necrosis of the photoreceptors. ...
... Oxidative stress is one of the underlying mechanisms of circadian desynchronization and neural damage [10,15]. Like other studies [1,8], desynchronization through irregular lighting period exposure has been shown to decrease nocturnal melatonin synthesis. However, in our study a peak secretion occurred after one week of altered lightinginduced desynchronization. ...
Background: Owing to the non-biodegradability of
selenium, its prolonged consumption may lead to
adverse health outcomes. Aim and Objectives: The
study investigated the physiological effects of
prolonged selenium administrations in normal and
desynchronized rats. Material and Methods: Ninety
six cyclical adult female rats were divided into short (1
week) and long (8 weeks) experimental cohort
consisting of 6 groups each. Each experimental cohort
contained control, High Selenium Dose (HSD) (150
μg/kg), Low Selenium Dose (LSD) (100 μg/kg),
Desynchronized Group (AP), AP + HSD and AP +
LSD. Results: In normal rats, HSD administration
caused duration-dependent increase in ovarian PER1
expression and suprachiasmatic catalase and
Glutathione Peroxidase (GPx) levels. LSD admini-
stration resulted in duration-dependent increase in
Nocturnal Plasma Melatonin (NPM), ovarian PER1
expression, ovarian GPx and duration-dependent
increase and decrease in nighttime temperature and
ovarian catalase respectively. On the other hand, in AP
rats, HSD administration resulted in duration-
dependent increase in ovarian PER1, NPM and
suprachiasmatic catalase and duration-dependent
decrease in nocturnal plasma glucose and ovarian
catalase respectively. Also, LSD administration led to
duration-dependent decrease in ovarian GPX and
increase in ovarian PER1, suprachiasmatic GPX andcatalase levels respectively. Conclusion: In normal
rats, 8-week administration of 150 μg/kg of selenium
relatively improved ovarian PER1 expression and
glutathione peroxidase and catalase levels in
suprachiasmatic nucleus. Prolonged selenium admini-
strations caused beneficial effects in desynchronized
rats.
... There is conflicting evidence on whether or not the phase of circadian clock genes can be delayed by shift work. One team found that certain clock gene phases can be delayed, while other clock gene phases are unchanged by shift work [22]. Other researchers have found no significant delay in clock gene phase attributable to shift work [20]. ...
... Discrepancies may be due to a number of criteria, including but not limited to differences in length of the study, length of the night shift work, and differences in measurement methods. Regardless of the inconsistent findings, in 2019, the International Agency for Research on Cancer classified night shift work as a probable carcinogen to humans (Group 2A) [22]. ...
Sleep is an essential component of overall human health but is so tightly regulated that when disrupted can cause or worsen certain ailments. An important part of this process is the presence of the well-known hormone, melatonin. This compound assists in the governing of sleep and circadian rhythms. Previous studies have postulated that dysregulation of melatonin rhythms is the driving force behind sleep and circadian disorders. A computer-aided search spanning the years of 2015–2020 using the search terms melatonin, circadian rhythm, disorder yielded 52 full text articles that were analyzed. We explored the mechanisms behind melatonin dysregulation and how it affects various disorders. Additionally, we examined associated therapeutic treatments including bright light therapy (BLT) and exogenous forms of melatonin. We found that over the past 5 years, melatonin has not been widely investigated in clinical studies thus there remains large gaps in its potential utilization as a therapy.
... A combination of these two visions in near darkness condition, using both rod and cone cells, is known as mesopic vision (Innovative Lighting, 2018). This mesopic vision is adversely affected by ALAN and triggers sleep disorders and other health issues [1]. The impact of this disused light is associated not only with human health and energy wastage, but also astronomy, adverse effects on mammals, and even to some extent, plants [28]. ...
... The human eyes are receptive to only a portion of the natural light spectrum from violet to red which is known as visible light. It has been recently known that a blue share of this visible spectrum has the potential to regulate the time rhythms in humans and animals; this is commonly observed on day to day basis as loss of sleep due to mobile phone usage at night-time which uses blue light spectrum [1]. Typically, the illuminance of a sunlit surface is about 100,000 lx, a full moon night sky is approximately 0.2 lx, whereas streets at night are lit to about 5-50 lx. ...
Development in recent years has brought with it increased artificial light at night for amenity or security lighting, which has led to a noteworthy change in the night scenario and brightness of urban areas. Light pollution is now turning into a global issue as it is slowly fading away the ability to observe stars and originating various environmental and energy issues. It comprises glare, increased unrequited illumination, temporary lighting, and unexpected fluctuations in lighting. The sources are diverse, including streetlights, fishing boats, buildings, vehicle headlights, and even lights on under-sea research vessels; assimilation all these often results in the formation of a domical sky glow. This study attempts to address the issue of light pollution in an urban setting taking Bangalore, one of the fastest-growing cities in India as an example, with the help of night-time satellite imagery by the National Oceanic and Administrative Administration, USA. The study tries to observe a relationship between various demographical and spatial factors of the city with the brightness levels. The analysis shows a considerable relationship between road density and radiance. Further in a delineated area, site-specific situation and primary contributing sources are detailed. The inverse distance weighted simulation of the street illumination is found to be four times the Indian Standard recommendation. Despite light pollution protruding and having high risks to the environment, it is reducible through various practicable solutions. Lastly, the study tries to address light pollution by developing spatial strategies using GIS as a tool and concludes with future research directions.
... As anticipated, neoplasms are the most common type of sickness class annotated, followed by the phenotype of pathological states, signs, and symptoms ( Figure 7). The most prevalent disorders enriched in all treated samples included malignant prostate cancer (which was previously confirmed by a study [48]), glioblastoma, melanoma, tumor progression, and other cancer-related diseases confirming our previous study [15]. We have taken all significantly dysregulated DEGs in all the contrasts to get a comprehensive picture of the disease enrichment in the treated samples ( Figure 9A). ...
Objective
The effect of artificial light at night (ALAN) on “transcriptome” is prominent owing to its capacity for “desynchronization” of organismal physiology. Light influences the circadian rhythm. This study aims to explore the ALAN-induced ovarian transcriptome of zebrafish for desynchronization of life processes.
Methods
Four experimental conditions were set up for female zebrafish: one normal 12-hour light and 12-hour dark (LD) cycle, and three continuous exposures to ALAN for one week (LLW), one month (LLM), and one year (LLY). The whole transcriptome data analysis of the ALAN-exposed samples was then compared with the normal sample using RNA-Seq, followed by exploratory analyses.
Results
The analysis revealed two different patterns of expression of genes where LLW and LLM differ with LLY samples in comparison to LD. Compared to LD, downregulation of the predicted hub genes was observed in all treatments; ribosome and oxidative phosphorylation pathways were enriched. LLY vs. LD contrast depicts the enrichment of three more pathways—RNA polymerase, adhesion junction, and signaling. The gene ontology (GO) enrichment portrays more prevalent biological processes in LLW vs. LD and LLM vs. LD than in LLY vs. LD. Contrast-wise disease annotation represents neoplasms as the most prevalent; disease enrichment denotes the major class of neoplasm, carcinoma, coupled with intellectual disability, global developmental delay, and seizures.
Conclusion
Our study displayed desynchronization of various genes and pathways leading to the initiation of diseases, for the first time in zebrafish. Even though, this data shows that ALAN is a serious threat, further research is needed to determine the intensity and the duration of ALAN which might cause potential repercussions.
... En varios estudios epidemiológicos, el déficit de luz solar estuvo implicado en el aumento de las tasas de incidencia del cáncer de mama y el cáncer de próstata, especialmente en los países septentrionales, lo que concuerda con la hipótesis de la "vitamina D". Según esta hipótesis, la vitamina D puede desempeñar un papel fundamental en la reducción del riesgo, tanto de cáncer de mama como de próstata, mientras que la falta de exposición a la luz solar ultravioleta puede aumentar la prevalencia de la deficiencia de vitamina D y por lo tanto, puede hacer que las poblaciones predispuestas corran un mayor riesgo de desarrollar cáncer de mama y de próstata (Haim and Portnov, 2013). Un tema de fundamental importancia para el diseño de la iluminación del futuro es poder evaluar cuáles son las características circadianas de la luz que logra penetrar en estos espacios interiores. ...
... ALAN is the light that animals are exposed to at night which is considered hazardous or pollutant, it was first described by the astrologist and secondly by a chronobiologist and presently of a concerns to oncologist. Exposure to artificial light at night is currently a global phenomenon (Haim et al., 2019) and it has been implicated in several physiological alterations including: polycystic ovarian dysfunction in female rodents (Salvetti et al., 2003;Miloševi´c et al., 2005); alteration of circadian rhythm and metabolic processes (Fonken et al., 2013;Challet and Kalsbeek, 2017;Ali et al., 2017); melatonin suppression and ultimately downregulation of physiological processes (Falchi et al., 2011;Haim and Portnov, 2014;Zubidat et al., 2018). It also disrupts endocrine activity resulting in hormonal irregularities. ...
Exposure to various spectral of light at night is presently inevitable, hence the need to examine its spectral effect on male reproductive function. This study aimed at evaluating the periodical change in testicular histomorphology of albino rats exposed to various lights spectral {Blue (BL), Green (GL), Yellow (YL), Red (RL), and White (WL)} at night for 126 days. Compact fluorescence bulbs, 11 watts, maintained at 300 Lux, were used. At d63, d91, and d126, four rats per treatment were euthanized and the testes removed, weighed, and fixed in 10 % formalin for histological examination. Testicular weight (TW) was significant (p < 0.05) with the highest values under BL at d63, d91, and d126. Rats exposed to YL had the least significant (p < 0.05) TW at day 126. TW increased significantly (p < 0.05) under GL and significantly reduced (p < 0.05) under YL considering the difference between d63 and d126. Non-specific atrophic degeneration of seminiferous tubules was observed under darkness with age. Evidence of displacement and degeneration of the spermatogonia was observed under YL. Exposure to YL and darkness appeared to cause a threat to reproduction as BL and GL to enhance male reproductive function in the albino rats.
... Kim & Park, 2017;Portnov et al., 2020;Wu, 2014). However, if excessive or misdirected, PSL might lead to unnecessary energy waste (Gallaway et al., 2010;Kyba et al., 2014;Saad et al., 2021), pose a non-negligible threat to the nocturnal environment (Chang et al., 2013;Gaston et al., 2013Gaston et al., , 2015Hölker et al., 2010;Kraus, 2016;Lim et al., 2011;Rybnikova & Portnov, 2016;Silva et al., 2017;, and become a potential health hazard (Bauer et al., 2013;Cho et al., 2015;Haim & Portnov, 2013;Haim & Zubidat, 2015;Keshet-Sitton et al., 2017;Martin et al., 2012;Obayashi et al., 2014;Shane et al., 2012;Stevens et al., 2013;. ...
Public space lighting (PSL), if adequately designed, may significantly enhance pedestrians’ sense of safety and comfort. Yet, the accumulated knowledge about subjective evaluation of PSL is still insufficient. This paper presents a systematic literature review, carried out according to the PRISMA guidelines, of factors affecting pedestrians’ perceptions of safety, comfort, and pleasantness induced by PSL. The screening process, which focused on studies combining technical- and observer-based environmental assessments, yielded 53 eligible papers, which were then synthesized according to an adapted model for outdoor place-human relationship. This framework-based review comprehensively highlights a few common findings and practical implications, as well as multiple gaps in research coverage, many inconsistencies, and significant generalization and transferability constraints. As the review indicates, one size does not fit all, and much further research is needed to improve the tailoring of PSL to a range of contextual conditions, such as different climates, cultures, and city characteristics.
... Using satellite night-time light (NTL) data as a proxy for on-ground human activity was well established in the remote sensing literature of the 1970s [1]. Since then, NTL data have been widely used as a remote proxy for different purposes: in studies of the economic performance of regions [2][3][4][5][6][7][8][9], in population analyses [10][11][12][13][14][15], in health geography studies [16][17][18][19][20], in studies of CO2 emissions [21][22][23][24], etc. (for a comprehensive review of current NTL usage and outlook for its future usage, see [25]). ...
Night-time light (NTL) data have been widely used as a remote proxy for the economic performance of regions. The use of these data is more advantageous than the traditional census approach is due to its timeliness, low cost, and comparability between regions and countries. Several recent studies have explored monthly NTL composites produced by the Visible Infrared Imaging Radiometer Suite (VIIRS) and revealed a dimming of the light in some countries during the national lockdowns due to the COVID-19 pandemic. Here, we explicitly tested the extent to which the observed decrease in the amount of NTL is associated with the economic recession at the subnational level. Specifically, we explore how the association between Gross Domestic Product (GDP) and the amount of NTL is modulated by the pandemic and whether NTL data can still serve as a sufficiently reliable proxy for the economic performance of regions even during stressful pandemic periods. For this reason, we use the states of the US and quarterly periods within 2014–2021 as a case study. We start with building a linear mixed effects model linking the state-level quarterly GDPs with the corresponding pre-processed NTL data, additionally controlling only for a long-term trends and seasonal fluctuations. We intentionally do not include other socio-economic predictors, such as population density and structure, in the model, aiming to observe the ‘pure’ explanatory potential of NTL. As it is built only for the pre-COVID-19 period, this model demonstrates a rather good performance, with R2 = 0.60, while its extension across the whole period (2014–2021) leads to a considerable worsening of this (R2 = 0.42), suggesting that not accounting for the COVID-19 phenomenon substantially weakens the ‘natural’ GDP–NTL association. At the same time, the model’s enrichment with COVID-19 dummies restores the model fit to R2 = 0.62. As a plausible application, we estimated the state-level economic losses by comparing actual GDPs in the pandemic period with the corresponding predictions generated by the pre-COVID-19 model. The states’ vulnerability to the crisis varied from ~8 to ~18% (measured as a fraction of the pre-pandemic GDP level in the 4th quarter of 2019), with the largest losses being observed in states with a relatively low pre-pandemic GDP per capita, a low number of remote jobs, and a higher minority ratio.
... Artificial light at night has been shown to produce undesired disruptive effects on wildlife (Longcore and Rich, 2004;Rich and Longcore, 2006;Hölker et al., 2010;Davies et al., 2013;Svechkina et al., 2020;Gaston et al., 2021) as well as in relevant aspects of human health (Davis et al., 2001;Haim and Portnov, 2013;Stevens et al., 2014;Smolensky et al., 2015;García-Sáenz et al., 2018;Russart and Nelson, 2018;Boyce, 2022). These unwanted effects add to the progressive loss of the starry night sky (Cinzano et al., 2001;Falchi et al., 2016;Bará, 2016), whose negative consequences for the sustainability of the scientific activity of ground-based astronomical observatories (Walker, 1970;Garstang, 1989;Green et al., 2022), and the preservation of humankind's intangible cultural heritage (Marin and Jafari, 2008) have been noticed since longtime ago. ...
Light pollution can be rigorously described in terms of the volume concentration of anthropogenic photons (light quanta) in the terrestrial atmosphere. This formulation, consistent with the basic physics of the emission, scattering and absorption of light, allows one to express light pollution levels in terms of particle volume concentrations, in a completely analogous way as it is currently done with other classical pollutants, like particulate matter or molecular contaminants. In this work we provide the explicit conversion equations between the photon volume concentration and the traditional light photometry quantities. This equivalent description of the light pollution levels provides some relevant insights that help to identify artificial light at night as a standard pollutant. It also enables a complementary way of expressing artificial light exposures for environmental and public health research and regulatory purposes.
... Artificial light at night has been shown to produce undesired disruptive effects on wildlife (Longcore and Rich, 2004;Rich and Longcore, 2006;Hölker et al., 2010;Davies et al., 2013;Svechkina et al., 2020;Gaston et al., 2021) as well as in relevant aspects of human health (Davis et al., 2001;Haim and Portnov, 2013;Stevens et al., 2014;Smolensky et al., 2015;García-Sáenz et al., 2018;Russart and Nelson, 2018;Boyce, 2022). These unwanted effects add to the progressive loss of the starry night sky (Cinzano et al., 2001;Falchi et al., 2016;Bará, 2016), whose negative consequences for the sustainability of the scientific activity of ground-based astronomical observatories (Walker, 1970;Garstang, 1989;Green et al., 2022), and the preservation of humankind's intangible cultural heritage have been noticed since longtime ago. ...
Light pollution can be rigorously described in terms of the volume concentration of anthropogenic photons (light quanta) in the terrestrial atmosphere. This formulation, consistent with the basic physics of the emission, scattering and absorption of light, allows one to express light pollution levels in terms of particle volume concentrations, in a completely analogous way as it is currently done with other classical pollutants, like particulate matter or molecular contaminants. In this work we provide the explicit conversion equations between the photon volume concentration and the traditional light photometry quantities. This equivalent description of the light pollution levels provides some relevant insights that help to identify artificial light at night as a standard pollutant. It also enables a complementary way of expressing artificial light exposures for environmental and public health research and regulatory purposes.
... The importance of the circadian timing system and its entrainment by light-dark cycles is best demonstrated by the prevalence of increased health risks and in some cases disturbances within ecological systems, which emerge from disruptions of the circadian clock network and desynchronization in timing of the different biological rhythms (Bird et al., 2004;Navara and Nelson, 2007;Rotics et al., 2011;Haim and Portnov, 2013). In modern society there are many artificially induced disruptions of the circadian system that have implications for both humans and animals that have received much attention both in the laboratory and more recently also in field studies. ...
Biological rhythms are rhythmic fluctuations of biological functions that occur in almost all organisms and on several time scales. These rhythms are generated endogenously and entail the coordination of physiological and behavioural processes to predictable, external environmental rhythms. The light-dark cycle is usually the most prominent environmental cue to which animals synchronise their rhythms. Biological rhythms are believed to provide an adaptive advantage to organisms. In the present review, we will examine the occurrence of circadian and seasonal rhythms in African mole-rats (family Bathyergidae). African mole-rats are strictly subterranean, they very rarely emerge aboveground and therefore, do not have regular access to environmental light. A key adaptation to their specialised habitat is a reduction in the visual system. Mole-rats exhibit both daily and seasonal rhythmicity in a range of behaviours and physiological variables, albeit to different degrees and with large variability. We review previous research on the entire circadian system of African mole-rats and discuss output rhythms in detail. Laboratory experiments imply that light remains the strongest zeitgeber for entrainment but in the absence of light, animals can entrain to ambient temperature rhythms. Field studies report that rhythmic daily and seasonal behaviour is displayed in their natural habitat. We suggest that ambient temperature and rainfall play an important role in the timing of rhythmic behaviour in mole-rats, and that they likely respond directly to these zeitgebers in the field rather than exhibit robust endogenous rhythms. In the light of climate change, these subterranean animals are buffered from the direct and immediate effects of changes in temperature and rainfall, partly because they do not have robust circadian rhythms, however, on a longer term they are vulnerable to changes in their food sources and dispersal abilities.
... The study by a group of researchers at the American Medical Association states that in a nationally representative cross-sectional survey of American teens, higher levels of outdoor ALAN, measured by satellite, were associated with bedtime hours in the last hours of the week; those in the lower night-light quartile reported the longest nocturnal sleep times [8]. ALAN also has a potential risk of prostate cancer in men and breast cancer in women [9]. ...
This study addresses the relationship between Sustainable Development Goals (SDGs) 2030 and artificial light at night (ALAN). In this research paper, different types of SDGs by the United Nations are discussed regarding the effects of ALAN on different goals. In addition, different policies associated with ALAN around the world are examined, and literature reviews are discussed. With this analysis and additional stakeholder discussions, several suggestions are introduced to create a better environment. Regarding different sustainable goals, we observe a trade-off between SDGs and ALAN. It is necessary to discuss different stakeholders, to minimize the negative impact of light pollution and make better policies for the world. One cannot attain SDGs 2030 without considering ALAN. We hope this paper will be helpful to create better policies for sustainable development.
... Short-term exposure to ALAN was, however, not associated with alterations in immunity or oxidative stress in adult fishes (Kupprat et al., 2021) and birds (Raap et al., 2016b), suggesting that longer exposure and/or a more vulnerable developmental stage might be required to have deleterious effects if any. Accordingly, in humans and rodents, prolonged ALAN exposure is associated with an increased prevalence of obesity, type 2 diabetes, hypertension, affective disorders or specific cancers (Wyse et al., 2011;Haim and Portnov, 2013;Fonken and Nelson, 2014). ...
Artificial light at night (ALAN) affects numerous physiological and behavioural mechanisms in various species by potentially disturbing circadian timekeeping systems and modifying melatonin levels. However, given the multiple direct and indirect effects of ALAN on organisms, large-scale transcriptomic approaches are essential to assess the global effect of ALAN on biological processes. Moreover, although studies have focused mainly on variations in gene expression during the night in the presence of ALAN, it is necessary to investigate the effect of ALAN on gene expression during the day. In this study, we combined de novo transcriptome sequencing and assembly, and a controlled laboratory experiment to evaluate the transcriptome-wide gene expression response using high-throughput (RNA-seq) in Bufo bufo tadpoles exposed to ecologically relevant light levels. Here, we demonstrated for the first time that ALAN affected gene expression at night (3.5% and 11% of differentially expressed genes when exposed to 0.1 and 5 lx compared to controls, respectively), but also during the day (11.2% of differentially expressed genes when exposed to 5 lx compared to controls) with a dose-dependent effect. ALAN globally induced a downregulation of genes (during the night, 58% and 62% of the genes were downregulated when exposed to 0.1 and 5 lx compared to controls, respectively, and during the day, 61.2% of the genes were downregulated when exposed to 5 lx compared to controls). ALAN effects were detected at very low levels of illuminance (0.1 lx) and affected mainly genes related to the innate immune system and, to a lesser extend to lipid metabolism. These results provide new insights into understanding the effects of ALAN on organism. ALAN impacted the expression of genes linked to a broad range of physiological pathways at very low levels of ALAN during night-time and during daytime, potentially resulting in reduced immune capacity under environmental immune challenges.
... These data, however, are panchromatic (that is, each pixel of NTL image reports summarized intensities of light in the diapason of 500-900 nm [18]). In the meantime, information about NTL color is of great importance for a variety of research, since it is known, for instance, that NTL emissions of different diapasons are associated with different economic activities and land-use types [19][20][21], or that NTL in blue diapason is especially effective in melatonin suppression [22] and thus inducing hormone-dependent cancers [23] and obesity [24]. Red, reason might be in the lack of training data and high correlation between spectral bands, which require a moderately deep CNN; as a recent study confirms (see [40]), such a CNN, consisting of 6 layers only, outperforms both shallow and very deep CNN. ...
Data on artificial night-time light (NTL), emitted from the areas, and captured by satellites, are available at a global scale in panchromatic format. In the meantime, data on spectral properties of NTL give more information for further analysis. Such data, however, are available locally or on a commercial basis only. In our recent work, we examined several machine learning techniques, such as linear regression, kernel regression, random forest, and elastic map models, to convert the panchromatic NTL images into colored ones. We compared red, green, and blue light levels for eight geographical areas all over the world with panchromatic light intensities and characteristics of built-up extent from spatially corresponding pixels and their nearest neighbors. In the meantime, information from more distant neighboring pixels might improve the predictive power of models. In the present study, we explore this neighborhood effect using convolutional neural networks (CNN). The main outcome of our analysis is that the neighborhood effect goes in line with the geographical extent of metropolitan areas under analysis: For smaller areas, optimal input image size is smaller than for bigger ones. At that, for relatively large cities, the optimal input image size tends to differ for different colors, being on average higher for red and lower for blue lights. Compared to other machine learning techniques, CNN models emerged comparable in terms of Pearson’s correlation but showed performed better in terms of WMSE, especially for testing datasets.
... However, as it generally happens with successful technical developments, it has also negative side-effects whose importance and extent are being revealed by a growing body of research. These detrimental effects are not limited to a specific field, but transversally affect the environment, the nocturnal landscape, the starry sky as a scientific and cultural global commons, and arguably, public health, among others ( Aubé et al., 2020 ;Alamús et al., 2017 ;AMA 2012 ;Bará, 2016 ;Bennie et al., 2015 ;Bonmati-Carrion et al., 2014 ;Cho et al., 2015 ;Cinzano et al., 2001 ;Czeisler, 2013 ;Davies et al., 2014Davies et al., , 2015T.W. 2016Dobler et al., 2015Dobler et al., , 2016Falchi et al., 2016 ;Garcia-Saenz et al., 2018 ;Gaston et al., 2013Gaston et al., , 2014 ; van Grunsven et al., 2020 ;Haim and Portnov, 2013 ;Hölker et al., 2010Hölker et al., , 2010bKyba et al., 2017 ;Longcore and Rich, 2004 ;Marin and Jafari, 2008 ;Rich and Longcore, 2006 ;Portnov, 2016 , N. 2018 ;Falcón et al., 2020 ;Sanders et al., 2020 ). Being artificial light at night (ALAN) a pollu-tant with important and widely studied effects on wildlife and flora, addressing its negative consequences is becoming part of the public agenda in many countries of the world Falchi et al., 2011 ;Falchi and Bará, 2020 ;Longcore et al., 2015 ;Schroer et al., 2020 ;Zieli ń ska-D ąbkowska et al., 2020 ). ...
The prevailing regulatory framework for light pollution control is based on establishing conditions on individual light sources or single installations (regarding features like ULOR, spectrum, illuminance levels, glare, ...), in the hope that an ensemble of individually correct lighting installations will be effective to somehow solve this problem. This "local sources" approach is indeed necessary, and shall no doubt be enforced; however, it seems to be clearly insufficient for curbing the actual process of degradation of the night, and for effectively attaining the necessary remediation goals. In this paper we describe a complementary (not substitutive) 'red-lines' strategy that should in our opinion be adopted as early as possible in the policies for light pollution control. It is based on setting maximum values for absolute light pollution indicators and using linear models relating the indicators to the source emissions in order to establish the maximum light emissions compatible with these red-lines. This top-down approach seeks to set definite limits on the allowable degradation of the night, providing the methodological tools required for making science-informed public policy decisions and for managing the transition processes. Light pollution abatement should routinely be included as an integral part of any territorial management plan. A practical application case-study based on the night sky brightness at zenith is described to illustrate these concepts.
... Short-term exposure to ALAN was, however, not associated with alterations in immunity or oxidative stress in adult fishes (Kupprat et al., 2021) and birds (Raap et al., 2016b), suggesting that longer exposure and/or a more vulnerable developmental stage might be required to have deleterious effects if any. Accordingly, in humans and rodents, prolonged ALAN exposure is associated with an increased prevalence of obesity, type 2 diabetes, hypertension, affective disorders or specific cancers (Wyse et al., 2011;Haim and Portnov, 2013;Fonken and Nelson, 2014). ...
Artificial light at night (ALAN) affects numerous physiological and behavioural mechanisms in various species by potentially disturbing circadian timekeeping systems. Although gene-specific approaches have already shown the deleterious effect of ALAN on the circadian clock, immunity and reproduction, large-scale transcriptomic approaches with ecologically relevant light levels are still lacking to assess the global impact of ALAN on biological processes. Moreover, studies have focused mainly on variations in gene expression during the night in the presence of ALAN but never during the day. In a controlled laboratory experiment, transcriptome sequencing of Bufo bufo tadpoles revealed that ALAN affected gene expression at both night and daytime with a dose-dependent effect and globally induced a downregulation of genes. ALAN effects were detected at very low levels of illuminance (0.1 lux) and affected mainly genes related to the innate immune system and, to a lesser extend to lipid metabolism. These results indicate that a broad range of physiological pathways is impacted at the molecular level by very low levels of ALAN potentially resulting in reduced survival under environmental immune challenges.
... In the literature, there are known factors for the risk of getting cancer and due to that the disease is very complex, some factors are unknown (we try to describe stochastic interactions). The most-reported cancer risk factors are genetic factors [Dawson et al., 2012] or mutations [Castillo et al., 2017] (because our ancestors had some risk gene), environmental factors [Haim & Portnov, 2013;Forman & Burley, 2006] (pollution, ultraviolet rays, electromagnetic radiation), dietary factors [Qian et al., 1994] (processed foods, foods with aflatoxins), behavioral [Parkin et al., 2011] (smoking, alcoholism, or sedentary lifestyle), and viral infections [Fernandes et al., 2017] (human papillomavirus or sexually transmitted diseases, hepatitis B, C viruses and so on). ...
In this paper, we explore the interplay between tumor cells and the human immune system, based on a deterministic mathematical model of minimal interactions by transforming it to stochastic model using a continuous-time Markov chain, where time is continuous but the state space is discrete. Furthermore, we simulate the stochastic basin of attraction to verify the behavior of the three critical points of interest in the deterministic system. Moreover, the stochastic simulations exemplify the cancer immunoediting theory in its three phases of development: elimination, equilibrium and escape. We extend the minimum model proposed in [DeLisi & Rescigno, 1977] to include a term of immunotherapy by lymphocyte injection, and we simulate two treatment regimes, equilibrium and escape, under several schemes.
... As figure A11 (a) shows, for most BC rate cut-off thresholds, the association between the observed BC rates is consistently higher for blue lights than either for panchromatic or green-and red-band lights. This result is fully consistent with existing empirical evidence about most efficient melatonin suppression by short wavelength (blue) illumination ( [28], [63], [64]), potentially associated with elevated risk of hormonedependent cancers [65]. Importantly, the RGB estimates, obtained from the models without HBASE-based predictors ( Fig. A11 (b)) show weaker and more similar one to another correlations with BC DKD rates, which evidences that retaining the HBASE predictors in the models is beneficial. ...
Artificial light-at-night (ALAN), emitted from the ground and visible from space, marks human presence on earth. Since the launch of the Suomi National Polar Partnership satellite with the Visible Infrared Imaging Radiometer Suite Day-Night Band (VIIRS/DNB) onboard, global nighttime images have significantly improved; however, they remained panchromatic. Although multispectral images are also available, they are either commercial or free of charge, but sporadic. In this article, we use several machine learning techniques, such as linear, kernel, random forest regressions, and elastic map approach, to transform panchromatic VIIRS/DBN into red, green, blue (RGB) images. To validate the proposed approach, we analyze RGB images for eight urban areas worldwide. We link RGB values, obtained from ISS photographs, to panchromatic ALAN intensities, their pixel-wise differences, and several land-use-type proxies. Each dataset is used for model training, while other datasets are used for model validation. The analysis shows that model-estimated RGB images demonstrate a high degree of correspondence with the original RGB images from the ISS database. Yet, estimates, based on linear, kernel, and random forest regressions, provide better correlations, contrast similarity, and lower WMSEs levels, while RGB images, generated using elastic map approach, provide higher consistency of predictions.
... Outdoor artificial light at night has been associated all forms of cancer (Al-Naggar and Anil, 2016), breast cancer (Al-Naggar and Anil, 2016; Bauer et al., 2013;Cho et al., 2015;Garcia-Saenz et al., 2018;Hurley et al., 2015;James et al., 2017;Keshet-Sitton et al., 2017;Kim et al., 2015;Lai et al., 2020;Portnov et al., 2016;Ritonja et al., 2020;Rybnikova et al., 2015;Svechkina et al., 2020;Wu et al., 2021;Xiao et al., 2020b), prostate cancer (Al-Naggar and Anil, 2016; Garcia-Saenz et al., 2018;Kim et al., 2017;Rybnikova et al., 2017;Svechkina et al., 2020), colorectal cancer (Al-Naggar and Anil, 2016; Garcia-Saenz et al., 2020), non-Hodgkin lymphoma (Zhong et al., 2020), lung cancer (Al-Naggar and Anil, 2016), mood disorder (Paksarian et al., 2020), anxiety disorder (Paksarian et al., 2020), bipolar disorder (Paksarian et al., 2020), social phobia (Paksarian et al., 2020), depression (Min and Min, 2018;Svechkina et al., 2020), suicidal behaviours (Min and Min, 2018), obesity (Koo et al., 2016;Rybnikova et al., 2016;Svechkina et al., 2020;Zhang et al., 2020a), poorer cardiovascular outcomes (Lane et al., 2017), and sleep problems (Koo et al., 2016;Paksarian et al., 2020;Svechkina et al., 2020;Xiao et al., 2020a). The underlying mechanism is thought to relate largely to endocrine disruption, since light is the principal zeitgeber in synchronising human circadian rhythmicity, and circadian dysregulation has widespread neuroendocrinological effects on melatonin signalling, metabolic function, cancer resistance, and other systems (Ouyang et al., 2018;Russart and Nelson, 2018), although general stress has also been proposed (Haim and Portnov, 2013). ...
Exposure to green space has been associated with a range of human health benefits, largely in spatial epidemiological studies. Green space and artificial light at night are both associated with breast and prostate cancer, depressive symptoms, obesity, and sleep problems, and are both influenced by the built environment and urbanisation. We identified a negative correlation between green space diversity and outdoor artificial light at night for Australian major cities. Outdoor artificial light at night is therefore a potential, but overlooked, confounder in spatial epidemiological studies of green space exposure and human health, and should be incorporated into future models.
... It was shown by numerous studies that the ever increasing amount of artificial light at night (ALAN) has far reaching consequences, not only for astronomy, energy consumption and carbon footprint, but also for animal and human health (Chepesiuk 2009;Haim & Portnov 2013;Cho et al. 2015;Garcia-Saenz et al. 2018), ecosystems (Longcore & Rich 2004) and biodiversity (Hölker et al. 2010). Because ALAN impacts life on Earth in such a drastic way, and on a global scale, it was proposed to monitor light pollution in a similar manner as other pollutants. ...
In the last decade, numerous sky quality meters (SQMs) have been installed around the world, aiming to assess the temporal change of the night sky brightness, and thus the change in light pollution. However, it has become clear that SQM readings may be affected by ageing effects such as degradation of the sensor sensitivity and/or loss of transmissivity of optical components (filter, housing window). To date, the magnitude of the darkening has not been assessed in a systematic way. We report for the first time on the quantification of the SQM ageing effect and describe the applied method. We combine long-term SQM measurements obtained between 2011 and 2019 in Potsdam-Babelsberg (23 km to the south-west of the centre of Berlin), Vienna and Stockholm with a readily available empirical twilight model, which serves as a calibrator. Twilight SQM observations, calibrated for changing Sun altitudes, reveal a linear degradation of the measurement systems (SQM + housing window) with the following slopes: 34 ± 4, 46 ± 2 and 53 ± 2 mmagSQM arcsec−2 yr−1 for Stockholm, Potsdam-Babelsberg and Vienna, respectively. With the highest slope found in Vienna (latitude ∼48°) and the lowest one found in Stockholm (latitude ∼59°), we find an indication for the dependence of the trend on solar irradiance (which is a function of geographic latitude).
... Artificial light-at-night (ALAN) images, provided by the U.S. Defense Meteorological Satellite Program (US-DMSP) from 1992 to 2013, and, after 2013, by the Suomi National Polar Partnership Visible Infrared Imaging Radiometer Suite (SNPP-VIIRS), are used by researchers from different fields. In particular, these data have been used for ecology and astronomy research (Bennie et al., 2015;Cinzano et al., 2000;Duriscoe et al., 2018;Falchi et al., 2016;Hu et al., 2018), for health assessments (Davis et al., 2001;Haim and Portnov, 2013;Hansen, 2001;Kloog et al., 2010Kloog et al., , 2009McFadden et al., 2014;Rybnikova et al., 2017Rybnikova et al., , 2016Schernhammer, 2014), demographic analysis Elvidge et al., 1997;Sutton et al., 2001), and in studies of economic performance of countries and regions (Doll et al., 2000;Ghosh et al., 2010;Henderson et al., 2012;Kulkarni et al., 2011;Mellander et al., 2015;Sutton et al., 2007). ...
Knowledge-based economic activities (aka quaternary industries or QIs) are characterized by high concentrations of labour force and potentially high night-time light emissions. Therefore, geographic concentrations of such activities can presumably be identified using information on the amount artificial light at night (ALAN), which different geographic areas emit. Question, however, remains whether the models, incorporating ALAN data, are place-specific or whether such models are sufficiently generic, thus making it possible to apply them, once estimated, to other countries and continents. To answer this question, the analysis is performed in several phases. First, we build separate models for European NUTS3 regions and US counties. Next, we cross-validate these models and use them to predict QI concentrations worldwide. As the analysis shows, cross-validation of the models, applied to the “counterpart” continent, also results in a reasonably good fit, with R² reaching 0.852, when the US-model is applied to the EU data, and R² = 0.896, when the EU-model is applied to the US data. Although attempts to use ALAN data for the analysis of different socio-economic phenomena are not new, to the best of our knowledge, this is the study first that uses cross-continent validation of ALAN-based models to determine their generality.
... It was shown by numerous studies that the ever increasing amount of artificial light at night (ALAN) has far reaching consequences, not only for astronomy, energy consumption and carbon footprint, but also for animal and human health (Chepesiuk 2009;Haim & Portnov 2013;Cho et al. 2015;Garcia-Saenz et al. 2018), ecosystems (Longcore & Rich 2004) and biodiversity (Hölker et al. 2010). Because ALAN impacts life on Earth in such a drastic way, and on a global scale, it was proposed to monitor light pollution in a similar manner as other pollutants. ...
In the last decade numerous Sky Quality Meters (SQMs) were installed throughout the globe, aiming to assess the temporal change of the night sky brightness (NSB), and thus the change in light pollution. However, it has become clear that SQM readings may be affected by aging effects such as degradation of the sensor sensitivity and/or loss of transmissivity of optical components (filter, housing window). To date, the magnitude of the darkening has not been assessed in a systematic way. We report for the first time on the quantification of the SQM aging effect and describe the applied method. We combine long-term SQM measurements obtained between 2011 and 2019 in Potsdam-Babelsberg (23 km to the southwest of the center of Berlin), Vienna and Stockholm with a readily available empirical twilight model, which serves as calibrator. Twilight SQM observations, calibrated for changing sun altitudes, reveal a linear degradation of the measurement systems (SQM + housing window) with the following slopes: 34$\pm$4, 46$\pm$2 and 53$\pm$2 milli-mag$_{\rm SQM}$ arcsec$^{-2}$ yr$^{-1}$ for Stockholm, Potsdam-Babelsberg and Vienna. With the highest slope found in Vienna (latitude $\sim$48$^\circ$) and the lowest one found in Stockholm (latitude $\sim$59$^\circ$), we find an indication for the dependence of the trend on solar irradiance (which is a function of geographic latitude).
Background: Recent research underscores a crucial connection between circadian rhythm disruption and cancer promotion, highlighting an urgent need for attention. Objectives: Explore the molecular mechanisms by which modern lifestyle factors—such as artificial light exposure, shift work, and dietary patterns—affect cortisol/melatonin regulation and cancer risk. Methods: Employing a narrative review approach, we synthesized findings from Scopus, Google Scholar, and PubMed to analyze lifestyle impacts on circadian health, focusing on cortisol and melatonin chronobiology as molecular markers. We included studies that documented quantitative changes in these markers due to modern lifestyle habits, excluding those lacking quantitative data or presenting inconclusive results. Subsequent sections focused solely on articles that quantified the effects of circadian disruption on adipogenesis and tumor microenvironment modifications. Results: This review shows how modern habits lead to molecular changes in cortisol and melatonin, creating adipose microenvironments that support cancer development. These disruptions facilitate immune evasion, chemotherapy resistance, and tumor growth, highlighting the critical roles of cortisol dysregulation and melatonin imbalance. Conclusions: Through the presented findings, we establish a causal link between circadian rhythm dysregulation and the promotion of certain cancer types. By elucidating this relationship, the study emphasizes the importance of addressing lifestyle factors that contribute to circadian misalignment, suggesting that targeted interventions could play a crucial role in mitigating cancer risk and improving overall health outcomes.
As an integral part of human chronobiology, the circadian system plays a crucial role in regulating key biological functions, including sleep and the intricate hormonal rhythms of melatonin (MLT) and cortisol (CORT). Scholars have increasingly recognized environmental stressors as significant contributors to disturbed sleep patterns. Albeit vigorously discussed individually, the literature lacks comprehensive insights into the synergistic effect of artificial light at night (ALAN) and noise. The aim of this review is to look into the intricate interplay of the ALAN effects on sleep architecture, the modulation of circadian function, and how this influences homeostatic sleep. Furthermore, ALAN suppresses MLT secretion, which is most pronounced in response to short wavelengths of light. In addition, this review will demonstrate how exposure to noise during sleep elevates CORT and noradrenaline levels, which contributes to stress-related diseases and sleep disturbances. ALAN and noise, persistently emitted into the environment, share intrinsic mechanisms with comparable characteristics. Therefore, understanding their combined impact has become increasingly urgent. Pre-sleep exposure to both ALAN and noise acts as a potent stressor, with the potential to disrupt sleep patterns. Interestingly, during sleep, noise emerges as the predominant influence on sleep quality. Moreover, these stressors often synergize and amplify one another’s adverse effects. Thus, limiting their exposure is crucial for cultivating a sustainable environment conducive to quality sleep and overall well-being.
If schoolchildren are exposed to artificial light at night and noise, they do not sleep well and wake up tired in the morning, which can adversely affect their school grades. In this study, we verify this hypothesis by measuring nighttime light and noise in schoolchildren’s bedrooms and comparing these measurements with their educational achievements in various subjects. During the six-week study, the schoolchildren used the AndroSensor smartphone app to monitor illumination and noise and the ZeppLife app to monitor sleep. The measurements were compared to the grades the schoolchildren obtained during the corresponding school quarter. Grades in Arabic, Hebrew, English, mathematics, humanities, and sciences were analysed separately. The analysis reveals that exposure to artificial light before sleep was significantly associated with low grades in all subjects, but particularly with grades in mathematics and sciences (p<0.01). Although the same effect was found for noise, the combined effect of nighttime light and noise was stronger if the two types of exposure occurred simultaneously. As we conclude, exposure to light and noise tends to interfere with educational achievements of schoolchildren and should therefore be a public policy concern.
As Aldeias do Xisto integram uma das três reservas Dark Sky do país com certificação “Destino Turístico Starlight” emitida pela Fundação Starlight e apoiada pela UNESCO, Organização Mundial de Turismo (UNWTO) e Instituto de Astrofísica das Canárias (IAC), que reconhece as condições excecionais destas áreas Transfronteiriças para a observação do Universo a partir da superfície da Terra, e atesta o compromisso entre entidades públicas, privadas e científicas para a sua manutenção. A crescente procura por atividades turísticas para observação do céu noturno é uma realidade que se acentuou a partir de 2020 com a pandemia COVID’19, evocada por um sentimento generalizado de reconhecida sustentabilidade no astroturismo português. As condições de excelência para a observação de fenómenos celestes a partir do lugar de Porto da Balsa, na freguesia de Fajão, que integra as 27 Aldeias do Xisto, proporcionaram desde 2009 o mapeamento do Cosmos pelo Instituto de Telecomunicações, com a implementação da estação radioastronómica para o desenvolvimento de ciências espaciais, elevando o município de Pampilhosa da Serra a Observatório Espacial ao serviço do Ministério da Defesa Nacional.
A visibilidade, transparência e escuridão do céu, que atrai para este território investigadores em astronomia, astrónomos amadores e astroturistas casuais, curiosos por aprender orientação polar, identificar constelações e conhecer as suas lendas, relacionar a cor das estrelas com as suas temperaturas, observar enxames de estrelas, nebulosas e galáxias distantes com a ajuda de telescópios, não pode ser comprometida pela poluição luminosa sob pena de degradar os argumentos construídos para a afirmação deste destino de interior. Os desígnios da ADXTUR – Agência para o Desenvolvimento Turístico das Aldeias do Xisto, em parceria com 21 Municípios da Região Centro e cerca de 200 operadores privados que atuam no território, centram-se na criação de riqueza e na preservação da cultura e do património do mundo rural beirão pelo desenvolvimento integrado, pela ressignificação dos lugares e pela afirmação do papel das aldeias no futuro do país. A certificação Starlight Tourism Destination assume, assim, um forte contributo na construção de um percurso da relação deste território com o céu, que ultrapassa a contemplação e fruição da observação para assumir um vetor estratégico entre o desenvolvimento turístico, a integração com o Sistema Científico e Tecnológico, a sustentabilidade social e ambiental, a capacitação das pessoas e o estímulo à economia.
Background:
Circadian disruption is a potential risk factor for advanced prostate cancer, and light at night (LAN) exposure may disrupt circadian rhythms. We evaluated whether outdoor LAN increases the risk of prostate cancer.
Methods:
We prospectively followed 49,148 participants in the Health Professionals Follow-up Study from 1986 through 2016. We estimated baseline and cumulative time-varying outdoor LAN with ~1 km2 resolution using data from the US Defense Meteorological Satellite Program's Operational Linescan System, which was assigned to participants' geocoded addresses. Participants reside in all 50 US states and reported a work or home address. We used multivariable Cox models to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between outdoor LAN and risk of overall (7,175 cases) and fatal (915 cases) prostate cancer adjusting for individual and contextual factors.
Results:
There was no association between the interquartile range increase in cumulative LAN and total (HR:1.02, 95% CI 0.98, 1.06) or fatal (HR: 1.05, 95% CI: 0.96, 1.15) prostate cancer in adjusted models. However, there was a positive association between baseline LAN and total prostate cancer among non-movers (HR: 1.06, 95% CI:1.00,1.14) including among highly screened participants (HR: 1.11, 95% CI:1.01,1.23).
Conclusions:
There was a suggestive positive association between baseline outdoor LAN and total prostate cancer. Additional studies with different measures of outdoor LAN and in more diverse populations are necessary.
Impact:
To our knowledge, this is the first longitudinal cohort study exploring the relationship between outdoor LAN and prostate cancer.
Hormone-dependent cancers and overweight/obesity are not necessarily linked but might have similar underlying causes, such as circadian disruption, lack of physical activity, and unhealthy nutrition. Several empirical studies also attribute the rise in these types of morbidity to vitamin D deficiency, linked in turn to insufficient sunlight exposure. Other studies place an emphasis on melatonin (MLT) hormone suppression, associated with artificial light at night (ALAN) exposure. Yet no studies, carried out to date, have attempted to determine which of these environmental risk factors is associated stronger with the morbidity types in question. In this study, we aim to narrow this knowledge gap by analyzing data available for 100+ countries worldwide, while controlling ALAN and solar radiation exposure estimates by several potential confounders, such as GDPpc, GINI inequality index and unhealthy food consumption. As the study reveals, all the morbidity types under analysis are significantly and positively associated with ALAN exposure estimates (p < 0.05), while solar radiation appears to be significantly associated with prostate cancer rates only (p < 0.05), but not with breast cancer or overweight/obesity rates (p > 0.1). To the best of our knowledge, this study is the first that separates the effects of ALAN and daylight exposures on the abovementioned types of morbidity.
COVID-19 is a highly contagious viral illness that has claimed millions of lives worldwide. Since its emergence, it has exerted a negative impact on many sectors globally without the exception of frontline COVID-19 healthcare providers. Specifically, in frontline COVID-19 healthcare workers, occupational stress-related sleep disorders such as insomnia and daytime somnolence have been extensively reported and were characterized by neuro-immunological changes. However, the possible mechanisms that underlie the sleep disorders have not been elucidated. The review was designed to highlight possible sleep mechanisms responsible for insomnia and daytime somnolence reported in frontline COVID-19 health workers. Available evidence shows that emotional perturbation, hypertension, chronobiological disruption and prolonged exposure to artificial light are among the events orchestrating occupational-stress-related sleep disorders in frontline COVID-19 healthcare workers. Anxiety-associated sleep anomaly is attributable to stimulation of the reticular activating system which occurs as a result of activation of noradrenergic fiber and sympatho-adrenal axis. Another mechanism includes depletion of hippocampal and brain glycogen by anxiety-induced activation of corticotropin releasing hormone (CRH)-secreting brain neurons and hypothalamic-corticotropic-adrenal cortex axis. Spontaneous discharge of noradrenergic fiber during basal state and changes in normal secretory rhythm of hypnosis-related chemical messengers may be responsible for hypertension- and chronobiological disruption-induced sleep disorders, respectively. Lastly, prolonged light exposure-induced suppression of melatonin secretion may elicit disruption of normal circadian sleep.
Physiological processes exhibit distinct rhythmic patterns influenced by external cues. External cues such as photic signal play an important role in the synchronization of physiological rhythms. However, excess of or indiscriminate exposure to photic signals exerts profound effects on physiological processes, disrupting normal hormonal secretory rhythms, altering sleep/wakefulness cycle, and impairing reproductive function. Alteration in sleep/wakefulness cycle, impairment in reproductive cycle, and disruption of normal hormonal secretory rhythms characterize risk groups for photic stress such as night workers, trans-meridian travelers, and night-active people. Evidence from primary studies is increasing on the tendency of selenium to reset internal biorhythms by targeting circadian proteins and melatonin. The review highlights the chronobiological roles of selenium.
We present long-term (4–10 yr) trends of light pollution observed at 26 locations, covering rural, intermediate, and urban sites, including the three major European metropolitan areas of Stockholm, Berlin, and Vienna. Our analysis is based on (i) night sky brightness (NSB) measurements obtained with sky quality metres (SQMs) and (ii) a rich set of atmospheric data products. We describe the SQM data reduction routine in which we filter for moon- and clear-sky data and correct for the SQM ‘aging’ effect using an updated version of the twilight method of Puschnig et al. (2021). Our clear-sky, aging-corrected data reveal short- and long-term (seasonal) variations due to atmospheric changes. To assess long-term anthropogenic NSB trends, we establish an empirical atmospheric model via multivariate penalized linear regression. Our modelling approach allows to quantitatively investigate the importance of different atmospheric parameters, revealing that surface albedo and vegetation have by far the largest impact on zenithal NSB. Additionally, the NSB is sensitive to black carbon and organic matter aerosols at urban and rural sites, respectively. Snow depth was found to be important for some sites, while the total column of ozone leaves impact on some rural places. The average increase in light pollution at our 11 rural sites is 1.7 per cent per year. At our nine urban sites, we measure an increase of 1.8 per cent per year and for the remaining six intermediate sites we find an average increase of 3.7 per cent per year. These numbers correspond to doubling times of 41, 39, and 19 yr. We estimate that our method is capable of detecting trend slopes shallower/steeper than ±1.5 per cent per year.
In the United States, African American (AA) men have a 2.4 times higher mortality rate due to prostate cancer than White men. The multifactorial causes of the racial disparities in prostate cancer involve various social determinants of health, socioeconomic status, and access to healthcare. However, emerging evidence also suggests that circadian rhythm disruption (CRD) contributes to prostate cancer, and AA men may be more susceptible to developing CRDs. Circadian rhythms play a significant role in metabolism, hormone secretion, and sleep/wake cycles. Disruption in these circadian rhythms can be caused by airplane travel/jetlag, night shift work, exposure to light, and neighborhood noise levels, which can contribute to sleep disorders and chronic conditions such as obesity, diabetes, cardiovascular disease, and depression. The drivers of the racial disparities in CRD include night shift work, racial discrimination, elevated stress, and residing in poor neighborhoods characterized by high noise pollution. Given the increased vulnerability of AA men to CRDs, and the role that CRDs play in prostate cancer, elucidating the clock-related prostate cancer pathways and their behavior and environmental covariates may be critical to better understanding and reducing the racial disparities in prostate cancer.
Schools usually develop a range of policies, procedures, and guidelines for managing the school in high-quality and provide students, parents, and staff with as much consistency and predictability as possible. One of them is uniform policy which demands all students to comply with the school’s dress code when students come to school. Uniform policies mainly expect students to have a strong commitment to wearing the correct school uniform for showing self-respect and respect to school community. Main issues
that are covered in uniform policies are the descriptions of school dress, PE kit, and requirements about keeping decorations in minimum. The major purpose of the uniform policies is to provide opportunities for increased school security, to inspire students to practice a greater sense of school identity and belonging, to improve positive student behavior, to lessen school clothing expenses, to improve the level of participation
and to expand academic excellence.
Astronomers undertake research by observing the universe to collect relevant data, which they analyse to deduce a model for the physical state of the objects observed. This enables them to make informed deductions about the origin and future evolution of planets, stars, galaxies and other astronomical bodies. Historically, these observations were made by ground-based astronomers using optical telescopes. Indeed, this has been the case for four centuries since Galileo Galilei first used a telescope for astronomy in 1609.
Nowadays, along with the rapid development of modern industry and scientific technical progress,
the human body is exposed to severe and long-term adverse effects of various anthropogenic factors. Both
chemical and physical factors lead to mutagenic and pro-oxidative changes in cells of all tissues of living
organisms. Among these factors, ionizing radiation is particularly noteworthy. The particular significance
of ionizing radiation is related to its strong, irreversible and destructive effects in organisms. On the other
hand it is assisiated with severe accidents in Chernobul and Fukushima earlier, in this century. Considering
the above mentioned reasons, investigations of high resistance of organisms to γ-irradiation through
upregulation of serotonergic system are one of the necessary requirements of the present time. The
significant impact of different kinds of unfavourable enviromental factors on the activity of serotonergic
system have been shown on numerous experimental models. For this aim in our experiments activation of
serotonergic system was achieved by intraperitanelly administration of serotonin-modulating
anticonsolidation protein [1] into the animals. This protein is shown to be in linear relation with serotonin
level.
A functional urban area (FUA) is a geographic entity that consists of a densely inhabited city and a less densely populated commuting zone, both highly integrated through labor markets. The delineation of FUAs is important for comparative urban studies and it is commonly performed using census data and data on commuting flows. However, at the national scale, censuses and commuting surveys are performed at low frequency, and, on the global scale, consistent and comparable data are difficult to obtain overall. In this paper, we suggest and test a novel approach based on artificial light at night (ALAN) satellite data to delineate FUAs. As ALAN is emitted by illumination of thoroughfare roads, frequented by commuters, and by buildings surrounding roads, ALAN data can be used, as we hypothesize, for the identification of FUAs. However, as individual FUAs differ by their ALAN emissions, different ALAN thresholds are needed to delineate different FUAs, even those in the same country. To determine such differential thresholds, we use a multi-step approach. First, we analyze the ALAN flux distribution and determine the most frequent ALAN value observed in each FUA. Next, we adjust this value for the FUA’s compactness, and run regressions, in which the estimated ALAN threshold is the dependent variable. In these models, we use several readily available, or easy-to-calculate, characteristics of FUA cores, such as latitude, proximity to the nearest major city, population density, and population density gradient, as predictors. At the next step, we use the estimated models to define optimal ALAN thresholds for individual FUAs, and then compare the boundaries of FUAs, estimated by modelling, with commuting-based delineations. To measure the degree of correspondence between the commuting-based and model-predicted FUAs’ boundaries, we use the Jaccard index, which compares the size of the intersection with the size of the union of each pair of delineations. We apply the proposed approach to two European countries—France and Spain—which host 82 and 72 FUAs, respectively. As our analysis shows, ALAN thresholds, estimated by modelling, fit FUAs’ commuting boundaries with an accuracy of up to 75–100%, being, on the average, higher for large and densely-populated FUAs, than for small, low-density ones. We validate the estimated models by applying them to another European country—Austria—which demonstrates the prediction accuracy of 47–57%, depending on the model type used.
Exposure to noise from road traffic and industries is known to be linked to various health dysfunctions, including hypertension, cardiovascular diseases and hearing loss. Exposure to artificial light at night (ALAN) is also increasingly recognized as being associated with ecosystem damage and various illnesses, including cancers, excessive weight gain and sleep disorders. However, measuring and monitoring these environmental risk factors by professional equipment are laborious and expensive, which impede large-scale research and various citizen science initiatives. In this study, we test a possibility that reliable noise and ALAN exposure estimates can be gathered using smartphones (SPs) sensors. To verify this assumption, we develop a standardized testing protocol, and use Andro-Sensor app, installed on three different Samsung Galaxy SPs – S7, S20FE5G, and SM520F, – to perform measurements of ALAN and noise in real-world conditions while comparing these measurements with measurements performed by professional (type 2) equipment – SL814 for noise and LX-1330B for illumination. The analysis of 3450 measurements, performed in two different locations in Israel, reveals that the SPs measurements and measurements performed by control instruments correlate strongly for noise (r = 0.76–0.94) and are nearly identical for ALAN (r = 0.998–0.999). The association between the two types of measurements is also found to be close to linear, with the slope of the trend line being close to 45° for ALAN and varying between 30° and 45° for noise, depending on the SPs used. Our conclusion is that the level of accuracy of ALAN measurements by SPs is greater for ALAN than for noise, which can make SPs a useful tool for large-scale ALAN studies that do not require the accuracy of professional instruments.
The spectacular progress of lighting equipment in recent decades has resulted in an enormous increase in outdoor lights and night-sky brightness which is the most noticeable effects of light pollution has increased rapidly in many countries. Any pollution is a consequence of urbanization forces, which correspond to a significant threat to human health and the environment. Despite the increasing awareness and interest, there is a need for quantification of light pollution at a national and local scale. In developing nations like India, the supremacy of basic issues often undermines the new-found urban problems that have the potential of affecting the environment at a larger scale. Light pollution is one such predicament that needs a response. This study intends to mark the fundamental concept of light pollution, its impacts, and develop an atlas of the ten most populated Indian cities following the magnitude of their brightness computed using high-resolution satellite data. It also attempts to relate the degree of brightness of these cities with safety in cities, which is the primary purpose of lighting at night, also taking into account various factors that may impact the night time lighting and safety in urban areas. According to the study, street lights installed in a city exhibit a considerable correlation with the brightness levels of the cities, which may point towards a significant source of light pollution in cities. The paper concludes with a discussion of some best practices in the context of light pollution and the scope for further investigation.
Light is crucial environmental factor for primary resource and signalling in plants and provide optimum fitness under fluctuating environments from millions of year. However, due to urbanization, and human development activities lot of excess light generated in environment during night time and responsible for anthro-pogenic generated pollution (ALAN; artificial night light pollution). This pollution has cause for serious problem in plants as it affects their processes and functions which are under the control of light or diurnal cycle. Plant biorhythms mostly diurnal rhythms such as stomatal movements, photosynthetic activity, and many more metabolic processes are under the control of period of light and dark, which are crucially affected by artificial light at night. Similarly, the crucial plant processes such as pollination, flowering, and yield determining processes are controlled by the diurnal cycle and ALAN affects these processes and ultimately hampers the plant fitness and development. To keep in mind the effect of artificial light at night on plant biorhythm and eco-physiological processes, this chapter will focus on the status of global artificial night light pollution and the responsible factors. Further, we will explore the details mechanisms of plant biorhythm and eco-physiological processes under artificial light at night and how this mechanism can be a global threat. Then at the end we will focus on the ANLP reducing strategies such as new light policy, advanced lightening technology such as remote sensing and lightening utilisation optimisation.
Sleep is a reversible state that sustains physiological and psychological processes in humans. As well established, individual-level factors, such as stress, smoking, drugs, and caffeine intake, reduce sleep duration and quality. However, studies of the effect of environmental risk factors, such as artificial light at night (ALAN) and noise, on sleep have been infrequent. Using records obtained from the 2017 Social Survey of Israel and combined with ALAN satellite data and various proxies for traffic noise, the present study aimed to determine how the combination of ALAN and traffic noise impact sleep duration and quality in urban areas. The increase of road density at the place of residence reduces average sleep duration by ~4.5% (~18 min.) and increases the frequency of reported sleep difficulties by ~3.5%, all other factors held equal. Similarly, an increase in ALAN exposure reduces average sleep duration by ~3% (~12 min) and increases the frequency of reported sleep difficulties by ~11%. The study also reveals a significant interaction between the two environmental risk factors in question, with the adverse impact of ALAN on sleep quality especially pronounced in high noise exposure areas.
Melatonin rhythms were assessed in 49 registered blind individuals by measurement of the urinary metabolite of melatonin, 6-sulfatoxymelatonin (aMT6s). Subjects had different causes of visual loss and were classified as having light perception or better (LP; n = 19) or having no perception of light (NPL; n = 30). Subjects collected four-hourly urine samples (eight-hourly overnight) for 48 h at weekly intervals for 3-5 weeks. The majority of LP subjects (14 of 19) had normally entrained aMT6s rhythms (mean acrophase range, 2.4-6.2 h), 4 were abnormally entrained to 24 h (mean acrophase range, 8.9-1.0 h), and 1 was unclassified. Conversely, most NPL subjects had abnormal rhythms (23 of 30), the incidence of which was greater in uni- and bilaterally enucleated subjects. The majority of NPL subjects (17 of 30) had free-running aMT6s rhythms period range, 24.13-24.79 h), 5 were abnormally entrained to 24 h (acrophase range, 7.2-20.6 h), and 1 was unclassified. Output (micrograms of aMT6s per 24 h) and amplitude (micrograms per h) of aMT6s production did not vary between LP and NPL subjects (mean 24-h output +/- SD, 12.7 +/- 7.5 and 9.4 +/- 6.4 micrograms aMT6s/24 h, respectively; mean amplitude +/- SD, 0.6 +/- 0.4 and 0.5 +/- 0.3 microgram/h, respectively). These results indicate that a higher proportion of NPL subjects have abnormal melatonin rhythms compared to those with LP.
Chromium (Cr) compounds are known occupational and environmental carcinogens. This trace element is found in the workplace primarily in the valence forms Cr(III) and Cr(VI). Cr(III), which was thought originally to be relatively nontoxic, was recently found to be more reactive toward purified DNA than was chromium(VI). Herein, we examined the ability of Cr(III) to induce oxidative DNA damage by measuring the formation of 8-hydroxydeoxyguanosine (8-OH-dG) in purified calf thymus DNA incubated with CrCl3 plus H2O2. In this system we observed that the Cr(III)-induced formation of 8-OH-dG in isolated DNA was both dose- and time-dependent. When melatonin and related molecules, including 6-methoxy-1,2,3,4-tetrahydro-β-carboline (pinoline), N-acetylserotonin, 6-hydroxymelatonin and indole-3-propionic acid, were co-incubated with CrCl3 plus H2O2, the accumulations of 8-OH-dG in DNA samples were markedly inhibited in a concentration-dependent manner. The concentrations of each indole required to reduce DNA damage by 50%, i.e. the IC50 values, were 0.48, 0.51, 0.88, 1.00 and 3.08 μM for pinoline, melatonin, N-acetylserotonin, 6-hydroxymelatonin and indole-3-propionic acid, respectively. These results suggest that one of the mechanisms by which Cr(III) may induce cancer is via Fenton-type reactions which generate the hydroxyl radical (○OH). The findings also indicate that the protective effects of melatonin and related molecules against Cr(III)-induced carcinogenesis relate to their direct ○OH scavenging ability which thereby reduces the formation of the damaged DNA product, 8-OH-dG.
Epidemiological studies have shown an association between rotating shiftwork and breast cancer (BC) risk. Recently, light at night (LAN) measured by satellite photometry and by self-reports of bedroom brightness has been shown to be associated with BC risk, irrespective of shiftwork history. Importance has been placed on these associations because retinal light exposures at night can suppress the hormone melatonin and/or disrupt circadian entrainment to the local 24-h light-dark cycle. The present study examined whether it was valid to use satellite photometry and self-reports of brightness to characterize light, as it might stimulate the circadian system and thereby affect BC incidence. Calibrated photometric measurements were made at the bedroom windows and in the bedrooms of a sample of female school teachers, who worked regular dayshifts and lived in a variety of satellite-measured sky brightness categories. The light levels at both locations were usually very low and were independent of the amount of satellite-measured light. Calibrated photometric measurements were also obtained at the corneas of these female school teachers together with calibrated accelerometer measurements for seven consecutive days and evenings. Based upon these personal light exposure and activity measurements, the female teachers who participated in this study did not have disrupted light-dark cycles like those associated with rotating shiftworkers who do exhibit a higher risk for BC. Rather, this sample of female school teachers had 24-h light-dark and activity-rest patterns very much like those experienced by dayshift nurses examined in an earlier study who are not at an elevated risk of BC. No relationship was found between the amount of satellite-measured light levels and the 24-h light-dark patterns these women experienced. It was concluded from the present study that satellite photometry is unrelated to personal light exposures as they might affect melatonin suppression and/or circadian disruption. More generally, photometric devices calibrated in terms of the operational characteristics of the human circadian system must be used to meaningfully link LAN and BC incidence.
Photoperiod is an important cue regulating biological rhythms in mammals, including 'blind' subterranean and sighted fossorial rodent species. These species may respond differentially to changes in light quality according to their retinal complexity. The effects of increasing light intensity on daily rhythms of urine excretion and urinary output of 6-sulfatoxymelatonin levels were compared in 'blind' mole rats Spalax ehrenbergi and sighted social voles, Microtus socialis. Our results show that the threshold irradiance required to entrain rhythms of voles is three magnitudes greater than that for mole rats. The results suggest that mole rats have an operational photoreceptive pathway with a lower threshold irradiance than voles. Such a low threshold reflects the remarkable capability of this 'blind' species to utilize light signals even under challenging light conditions.
Light treatment has been used as a non-pharmacological tool to help mitigate poor sleep quality frequently found in older people. In order to increase compliance to non-pharmacological light treatments, new, more efficacious light-delivery systems need to be developed. A prototype personal light-treatment device equipped with low brightness blue light-emitting diodes (LEDs) (peak wavelength near 470 nm) was tested for its effectiveness in suppressing nocturnal melatonin, a measure of circadian stimulation. Two levels of corneal irradiance were set to deliver two prescribed doses of circadian light exposure. Eleven older subjects, between 51 and 80 yrs of age who met the selection criteria, were exposed to a high and a low level of light for 90 min on separate nights from the personal light-treatment device. Blood and saliva samples were collected at prescribed times for subsequent melatonin assay. After 1 h of light exposure, the light-induced nocturnal melatonin suppression level was about 35% for the low-light level and about 60% for the high-light level. The higher level of blue light suppressed melatonin more quickly, to a greater extent over the course of the 90 min exposure period, and maintained suppression after 60 min. The constant exposure of the low-light level resulted in a decrease in nocturnal melatonin suppression for the last sampling time, whereas for the high-light level, suppression continued throughout the entire exposure period. The present study performed with healthy adults suggests that the tested personal light-treatment device might be a practical, comfortable, and effective way to deliver light treatment to those suffering from circadian sleep disorders; however, the acceptance and effectiveness of personal light-treatment devices by older people and by other segments of the population suffering from sleep disorders in a real-life situation need to be directly tested.
The incidence rates of cancers in men differ by countries of the world. We compared the incidence rates of three of the most common cancers (prostate, lung, and colon) in men residing in 164 different countries with the population-weighted light at night (LAN) exposure and with several developmental and environmental indicators, including per capita income, percent urban population, and electricity consumption. The estimate of per capita LAN exposure was a novel aspect of this study. Both ordinary least squares (OLS) and spatial error (SE) regression models were used in the analysis. We found a significant positive association between population exposure to LAN and incidence rates of prostate cancer, but no such association with lung cancer or colon cancer. The prostate cancer result is consistent with a biological theory and a limited number of previous studies of circadian disruption and risk. The LAN-prostate cancer connection is postulated to be due to suppression of melatonin and/or disruption of clock gene function. An analysis holding other variables at average values across the 164 countries yielded a risk of prostate cancer in the highest LAN-exposed countries 110% higher than in the lowest LAN exposed countries. This observed association is a necessary condition for a potentially large effect of LAN on risk of prostate cancer. However, it is not sufficient due to potential confounding by factors that increase the risk of prostate cancer and are also associated with LAN among the studied countries.
Case-control studies of melanoma have the potential for recall bias after much public information about the relation with ultraviolet radiation. Recall bias has been investigated in few studies and only for some risk factors. A nested case-control study of recall bias was conducted in 2004 within the Norwegian Women and Cancer Study: 208 melanoma cases and 2,080 matched controls were invited. Data were analyzed for 162 cases (response, 78%) and 1,242 controls (response, 77%). Questionnaire responses to several host factors and ultraviolet exposures collected at enrollment in 1991-1997 and in 2004 were compared stratified on case-control status. Shifts in responses were observed among both cases and controls, but a shift in cases was observed only for skin color after chronic sun exposure, and a larger shift in cases was observed for nevi. Weighted kappa was lower for cases than for controls for most age intervals of sunburn, sunbathing vacations, and solarium use. Differences in odds ratio estimates of melanoma based on prospective and retrospective measurements indicate measurement error that is difficult to characterize. The authors conclude that indications of recall bias were found in this sample of Norwegian women, but that the results were inconsistent for the different exposures.
Bright light can suppress nighttime melatonin production in humans, but ordinary indoor light does not have this effect. This
finding suggested that bright light may have other chronobiologic effects in humans as well. Eight patients who regularly
became depressed in the winter (as day length shortens) significantly improved after 1 week of exposure to bright light in
the morning (but not after 1 week of bright light in the evening). The antidepressant response to morning light was accompanied
by an advance (shift to an earlier time) in the onset of nighttime melatonin production. These results suggest that timing
may be critical for the antidepressant effects of bright light.
Hydroxyl radical damage in metastatic tumor DNA was elucidated in women with breast cancer, and a comparison was made with nonmetastatic tumor DNA. The damage was identified by using statistical models of modified base and Fourier transform-infrared spectral data. The modified base models revealed a greater than 2-fold increase in hydroxyl radical damage in the metastatic tumor DNA compared with the nonmetastatic tumor DNA. The metastatic tumor DNA also exhibited substantially greater base diversity than the nonmetastatic DNA, and a progression of radical-induced base damage was found to be associated with the growth of metastatic tumors. A three-dimensional plot of principal components from factor analysis, derived from infrared spectral data, also showed that the metastatic tumor DNA was substantially more diverse than the tightly grouped nonmetastatic tumor DNA. These cohesive, independently derived findings suggest that the hydroxyl radical generates DNA phenotypes with various metastatic potentials that likely contribute to the diverse physiological properties and heterogeneity characteristic of metastatic cell populations.
The effect of pineal indole hormone melatonin on colon carcinogenesis was firstly studied in rats. Two-month-old outbred female LIO rats were weekly exposed to 15 (experiment 1, groups 1 and 2) or to five (experiment 2, groups 1 and 2) s.c. injections of 1,2-dimethylhydrazine (DMH) at a single dose of 21 mg/kg of body weight. From the day of the first injection of the carcinogen DMH, the rats from groups 2 (experiments 1 and 2) were given melatonin five days a week during the night-time (from 18:00 h to 8:00 h), dissolved in tap water at 20 mg/l. The experiment was finalized in 6 months after the first injection of DMH. In both experiments the majority of tumors were localized in the descending colon. Tumors of the small intestines developed only in rats from experiment 1. Total incidence of colon tumors as well as tumors in different parts of the colon and the mean number of tumors per rat were much higher in rats from both groups in experiment 1 than that in rats from experiment 2. In experiment 1 melatonin failed to influence the total incidence of colon tumors. However, incidence of carcinomas in the ascending colon was significantly reduced (P < 0.01). The multiplicity of total colon tumors per rat, as well as the mean number of tumors, ascending and descending colon per rat, was also decreased under the influence of melatonin (group 2 vs group 1, P < 0.01). In the same experiment, melatonin slightly decreased the depth of tumor invasion and increased number of highly differentiated colon carcinomas induced by DMH. The percentage of small tumours in the descending colon among rats from group 2 was higher than that of group 1. Treatment with melatonin was also followed by a decrease in the multiplicity of DMH-induced tumors of the duodenum (group 2 vs group 1, P < 0.05) and by a decrease in the incidence of jejunum and ileum tumors (group 2 vs group 1, P < 0.05). In experiment 2, the inhibitory effect of melatonin on DMH-induced colon carcinogenesis was much more expressed than that in experiment 1. Thus, in group 1 the incidence of total colon tumors, ascending and descending colon tumors, was significantly decreased in comparison with group 2; also melatonin reduced the number of tumors per rat in the ascending and descending colon. The number of colon tumors that invaded only mucosa was significantly higher in group 2 than in group 1, P < 0.05. The ratio of highly differentiated tumors was increased (P < 0.05) and the ratio of low-differentiated tumors was decreased (P < 0.05) in rats exposed to melatonin (group 4) as compared with group 3. The number of large size tumors in the ascending and descending colon was decreased whereas the number of small size tumors (<10 mm2) was increased in those parts of the colon that were under the influence of melatonin in experiment 2. Thus, our results demonstrate the inhibitory effect of melatonin on intestinal carcinogenesis induced by DMH in rats.
Melatonin, the principal pineal gland hormone, exerts a direct antiproliferative effect on estrogen-responsive MCF-7 cells in culture. The purpose of the current study was to investigate the effects of melatonin on the invasion capacity of MCF-7 cells. In vitro, melatonin at physiological doses (1 nM) reduced (P < 0.001) the invasiveness of tumoral cells measured in Falcon invasion chambers. Subphysiological (0.1 pM) and pharmacological concentrations (10 microM) of melatonin failed to inhibit cell invasion. Melatonin was also able to block 17beta-estradiol-induced invasion (P < 0.001). Pretreatment of MCF-7 cells with 1 nM melatonin increased the response of tumoral cells to the anti-invasive effects of this indolamine. To explore possible mechanisms by which melatonin reduces invasiveness, we measured the attachment of MCF-7 cells to a basement membrane, the chemotactic response of the cells, and their type IV collagenolytic activity. The presence of melatonin (1 nM) in the culture medium significantly reduced the ability of MCF-7 cells to attach to the basement membrane; this effect was enhanced by pretreating the cells with the same indolamine (P < 0.001). Melatonin also counteracts the stimulatory effects of 17beta-estradiol on cell adhesion (P < 0.001). The chemotactic response of MCF-7 cells also decreased in the presence of 1 nM melatonin, and this melatonin-induced reduction of cell migration was more effective on cells that were previously incubated for 5 days with melatonin than it was on nonpretreated cells (P < 0.001). The simultaneous addition of 17beta-estradiol and melatonin resulted in a significantly lower chemotactic response than that of 17beta-estradiol-treated cells (P < 0.001). However, type IV collagenolytic activity was not influenced by melatonin. Our results demonstrate that melatonin reduces the invasiveness of MCF-7 cells, causing a decrease in cell attachment and cell motility, probably by interacting with the estrogen-mediated mechanisms of MCF-7 cell invasiveness. In addition, we also studied the influence of melatonin on the expression of two cell surface adhesion molecules (E-cadherin and beta1 integrin) and an intermediate filament protein (vimentin), the expression of which has been correlated with the relative invasive capacity of human breast cancer cells. The culture of tumor cells in the presence of melatonin (1 nM) increased the membrane staining for E-cadherin and beta1 integrin as well as the number of E-cadherin and beta1 integrin immunoreactive cells (P < 0.01). Neither control MCF-7 cells nor those treated with melatonin stained for vimentin. Preliminary in vivo experiments carried out on ovariectomized athymic nude mice implanted with 17beta-estradiol pellets and inoculated with 5 x 10(6) MCF-7 cells in the inguinal mammary fat pad suggest that melatonin could decrease the tumorigenicity of these tumor cells. However, these results need further confirmation. Taken together, our results suggest that melatonin shifts MCF-7 human breast cancer cells to a lower invasive status by increasing the beta1 integrin subunit and E-cadherin expression and promoting the differentiation of tumor cells. Finally, our study points out the existence of the anti-invasive actions of melatonin as a part of the oncostatic action of melatonin.
Previous studies on human breast cancer patients showed a decline in circulating melatonin levels corresponding to primary tumor growth and an increase when relapse occurred. The aim of the current investigation was to study in an experimental model possible mechanisms involved. Inbred female F344 Fischer rats were used for serial passages derived from a chemically induced mammary adenocarcinoma. Animals with slow-growing carcinosarcomas at passage 2 showed a significant elevation of nocturnal urinary melatonin (23.00–07.00 h; +50%, p
The purpose of this study was to investigate the size of the pupil while viewing through yellow and neutral density (ND) filters. Previous studies have shown that the pupil of the human eye is relatively more sensitive to short wavelengths than indicated by the photopic luminosity curve. We first measured the consensual horizontal pupil diameter of 11 observers as a function of luminance (0.144 to 18,150 cd/m2) to establish the luminance-response function for each observer. We then measured the pupil diameter while the observer viewed through a Corning Photochromic Filter (CPF) 550 lens and two ND filters (ND 0.5 and 1.0). The pupil diameters obtained with each filter were compared to the diameters at an equivalent luminance based upon each observer's luminance-response function. Our results show that the pupil diameter is larger with the yellow lens than when viewing a broad spectrum white field at an equivalent luminance. We speculate that our results may explain some, but not all, of the well-known subjective brightness enhancement that occurs when viewing through yellow filters.
A total of 10935 women with visual impairment were identified from the Finnish Register of Visual Impairment and followed up for cancer through the Finnish Cancer Registry for years 1983-1996. Breast cancer risk decreased by degree of visual impairment (P for trend 0.04) which suggests a dose-response relationship between visible light and breast cancer risk.
Background: Leisure time physical activity has previously been shown to be protective against cardiovascular disease. We estimated the influence of exercise, occupational physical activity, and household work with regard to risk of acute myocardial infarction (MI). Special interest was focused on potential interaction among these aspects of physical activity. Method: We analyzed data from a large population-based case-control study conducted in Stockholm, Sweden, 1992–1994. Cases comprised 1204 men and 550 women, age 45–70 years, who experienced their first MI during the study period. The controls, 1538 men and 777 women, were randomly selected from the study base, matched on sex, age, and hospital catchment area. The results were adjusted for several potential confounding factors. Results: Exercise, walking or standing at work, and doing demanding household work were all associated with decreased risk of acute MI; the estimated relative risks (RRs) ranged from 0.31 to 0.90 when all cases (fatal and nonfatal) were considered. In contrast, lifting or carrying at work, and an occupational workload perceived to be strenuous, were related to an increased risk of MI (RRs ranging from 1.10–1.57). We observed a synergistic benefit from exercise and walking or standing at work, and from household work and walking or standing at work. Conclusion: Aerobic physical activities such as exercise or walking at work seemed to reduce the risk of MI, whereas anaerobic activities such as heavy lifting at work were related to increased risk of MI.
The occurrence of melatonin (5-methoxy-N-acetyltryptamine), a common animal hormone, in extracts of the above-ground parts of 15-day-old plants of Chenopodium rubrum was confirmed by liquid chromatography/tandem mass spectrometry. Using both this method and radioimmunoassay, changes in melatonin content during a 12 hr light/12 hr dark cycle were demonstrated. The melatonin concentration remained low or undetectable during the light period and increased during the darkness reaching a maximum at hours 4–6 of the dark period before rapidly decreasing. Both the nocturnal increase and the range of concentration are similar to those known in animals.
The Mycobacterium bovis bacillus Calmette-Guerin cell-wall skeleton (BCG-CWS) activates Toll-like receptor (TLR) 2 and TLR4, but unlike the typical TLR4 agonist bacterial lipopolysaccharide barely induces type 1 IFN. BCG-CWS has been used for adjuvant immunotherapy for patients with cancer. We investigated the adjuvant potential of BCG-CWS for induction of CTLs subsequent to TLR-mediated dendritic cell (DC) maturation, using a syngeneic mouse tumor model (B16 melanoma in C57BL/6). We evaluated the retardation of tumor growth and cytotoxic response in wild-type and MyD88−/− mice immunized with tumor debris and/or BCG-CWS. Delays in tumor growth and cytotoxic response were induced by immunization with a mixture of BCG-CWS emulsion and the tumor. BCG-CWS was capable of activating DCs ex vivo by the criteria of CD80/CD86 up-regulation and cytokine (interleukin-12, tumor necrosis factor-α) induction. Efficient tumor suppression and ex vivo cytokine induction did not occur in MyD88-deficient mice and cells, suggesting that the MyD88 adapter is crucial for induction of tumor cytotoxicity. Because TLR4 is involved in both MyD88-dependent and -independent pathways and the latter affects DC maturation, our findings indicate that both pathways cooperate to induce CTL-based tumor immunity.
1. 1.|Resistance to cold through non-shivering thermogenesis (the absolute increase in O2 consumption caused by noradrenaline injection) was increased 3-fold in individuals of the broad-toothed mouse A. mystacinus, kept for 3 weeks under a short photoperiod (long scotophase 8L:16D) at an ambient temperature of 28°C, compared to control conditions (12L:12D; 28°C), and did not differ significantly from the winter-acclimatized group. 2. 2.|Acclimation of the same individuals to long scotophase and cold (8L:16d; 7°C) caused a significant (P < 0.01) increase in absolute O2 consumption and maximal body temperature, as a response to noradrenaline injectin, when compared to long-scotophase individuals (8L:16D; 28°C). 3. 3.|The results of this study support the idea that winter acclimatization of heat-production mechanisims may be induced by the extension of scotophase, which cycles very regulary in nature and in the Mediterranean region occurs before the beginning of the cold season.
The
tau
mutation in hamsters was recognized more than 12 years ago when a shipment of Syrian hamsters were found to have a short-period
circadian rhythm of 20 hours. As
Young
explains in a Perspective, although the intervening 12 years has revealed that the product of the
tau
gene is a crucial player in the intricate workings of the mammalian clock, its identity has remained a mystery. Now new findings
(
Lowrey
et al.) definitively show that
tau
encodes a casein kinase Ie and is a homolog of the clock gene double-time in the fruit fly. In wild-type hamsters, the casein
kinase Ie phosphorylates the crucial circadian clock protein, PER, which is retained in the cytoplasm and degraded. In
tau
hamsters, phosphorylation of PER is defective and so PER may be able to move to the nucleus and repress transcription of per
genes prematurely, speeding up the circadian clock.
Epidemiological studies have suggested a possible link between extremely low frequency electromagnetic fields (EMFs) and increased rates of certain cancers. One cancer that has been postulated to be associated with EMF exposure is breast cancer, for which increased rates have been reported among electricians. These cancer associations are weak, and the link to EMF exposures remains tenuous. Understanding the mechanisms by which EMFs could have biological effects will help in elucidating the risk, if any, from EMFs. One hypothesis that has received considerable attention involves reduction of melatonin levels by EMFs. This hypothesis suggests that loss of melatonin affects a variety of hormonal processes such as estrogen homeostasis and thereby may increase breast cancer rates. Since this theory was first presented, putative melatonin receptors have been cloned, providing new tools with which to examine melatonin's mechanism of action and the melatonin hypothesis. These receptors are found in nuclear and membrane fractions of cells. The nuclear receptors (retinoid Z receptors) are found both in the brain and in non-neural tissues, whereas the membrane-bound receptors are found primarily in neural tissue and have a higher affinity for melatonin. These receptors may control a variety of hormonal and immunological functions, including the release of gonadotropins from the hypothalamus and pituitary and 5-lipoxygenase activity in B lymphocytes. This Working Hypothesis briefly reviews our current knowledge of melatonin receptors and then provides theories on how the inactivation of melatonin receptors may cause cancer and suggests areas of research for addressing this question. Mol. Carcinog. 21:149–155, 1998. © 1998 Wiley-Liss, Inc.
1.1. The populations of the Levant vole, Microtus guentheri, inhabiting the Mediterranean ecosystem of Israel, are marginal populations which seem to be well adapted to its long dry and warm season. The thermoregulatory and metabolic responses of the Levant voles of Israel to manipulation of photoperiod were studied to assess to role of photoperiodicity in seasonal acclimatization.2.2. Resting metabolic rate (RMR) and body temperature at various ambient temperatures, overall thermal conductance, nonshivering thermogenesis, gross energy and digestible energy intake were measured in voles acclimated to long scotophase (8L:16D) and long photophase (16L:8D) at a constant ambient temperature of 25±1°C.3.3. This study