Sleep and light exposure across different levels of urbanisation in Brazilian communities

Quilombos are settlements originally founded by Africans and African descendants (Quilombolas) in remote parts of Brazil to escape slavery. Due to individual histories, Quilombos nowadays exhibit different states of industrialisation, making them ideal for studying the influence of electrification on daily behaviour. In a comparative approach, we aimed to understand whether and how human sleep changes with the introduction of artificial light. We investigated daily rest-activity-rhythms and sleep-patterns in the Quilombolas' by both wrist actimetry and the Munich ChronoType Questionnaire (MCTQ;the results of these two instruments correlated highly). Seven communities (MCTQ: N = 213/actimetry: N = 125) were compared in this study. Light exposure, phase of activity, sleep timing and duration differ across communities with various levels of urbanisation and histories of access to electricity. People living without electricity and those, who acquired it only very recently on average sleep earlier than those in more urbanised communities (mid-sleep about 1 hour earlier);sleep duration tends to be longer. Our results and those of others show that use of electricity and modern lifestyles have changed sleep behaviour. To understand the consequences of these changes for health, further studies are warranted

Effects of circadian disruption on physiology and pathology: from bench to clinic (and back)

Nested within the hypothalamus, the suprachiasmatic nuclei (SCN) represent a central biological clock that regulates daily and circadian (i.e., close to 24 h) rhythms in mammals. Besides the SCN, a number of peripheral oscillators throughout the body control local rhythms and are usually kept in pace by the central clock. In order to represent an adaptive value, circadian rhythms must be entrained by environmental signals or zeitgebers, the main one being the daily light?dark (LD) cycle. The SCN adopt a stable phase relationship with the LD cycle that, when challenged, results in abrupt or chronic changes in overt rhythms and, in turn, in physiological, behavioral, and metabolic variables. Changes in entrainment, both acute and chronic, may have severe consequences in human performance and pathological outcome. Indeed, animal models of desynchronization have become a useful tool to understand such changes and to evaluate potential treatments in human subjects. Here we review a number of alterations in circadian entrainment, including jet lag, social jet lag (i.e., desynchronization between body rhythms and normal time schedules), shift work, and exposure to nocturnal light, both in human subjects and in laboratory animals. Finally, we focus on the health consequences related to circadian/entrainment disorders and propose a number of approaches for the management of circadian desynchronization.Fil: Chiesa, Juan José. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Duhart, José Manuel. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Casiraghi, Leandro Pablo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Paladino, Natalia. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bussi, Ivana Leda. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Golombek, Diego Andrés. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Ancestral sleep.

While we do not yet understand all the functions of sleep, its critical role for normal physiology and behaviour is evident. Its amount and temporal pattern depend on species and condition. Humans sleep about a third of the day with the longest, consolidated episode during the night. The change in lifestyle from hunter-gatherers via agricultural communities to densely populated industrialized centres has certainly affected sleep, and a major concern in the medical community is the impact of insufficient sleep on health [1,2]. One of the causal mechanisms leading to insufficient sleep is altered exposure to the natural light-dark cycle. This includes the wide availability of electric light, attenuated exposure to daylight within buildings, and evening use of light-emitting devices, all of which decrease the strength of natural light-dark signals that entrain circadian systems [3]

A chronobiological policy to decrease the burden of hypertension and obesity in low- and middle-income population

The cardiovascular structure is temporally organized in both health and disease. The link between obesity and hypertension is elevated sympathetic nervous system activity and hormonal activity which present a clear rhythmicity, with the pineal, corticosteroid and leptin systems being those most implicated. Also, genetic mutations or deletions have implicated peripheral clock genes in the regulation of glucose homeostasis, lipid synthesis and adipogenesis, which are associated with obesity and type 2 diabetes mellitus. As hypertension and obesity are related, and the treatments of these disorders are well established but sometimes ineffective, this review focuses on chronobiological contributions to decrease the burden of hypertension and obesity in low- and middle-income groups of individuals. MEDLINE, Pubmed and SUMSearch sites (2001–2011) were used in the search strategy, together with the keywords: “antihypertensive drugs”; “arterial hypertension”; “circadian rhythms”; “obesity”; and “sleep quality”. Eighty-six articles were found and 50 articles from these were selected. A link between the circadian clock and hypertension has recently been described in animal models, using Clock-mutant mice that display metabolic syndrome. Experimental evidence clearly implicates circadian rhythms in the mechanisms that underlie the regulation of the blood pressure (BP) rhythm. Most clinical studies of BP focus on some pathological situation, such as hypertension, cardiovascular disease, sleep disorders, obesity, diabetes or pregnancy with blood biomarker alterations. However, epidemiological evidence for the role of circadian rhythms in hypertension has been lacking until recently. In Brazil, in an epidemiological, cross-sectional study, changed sleep quality and an earlier phase of mid-sleep were found in those using antihypertensive drugs. Moreover, some pharmacological studies support a circadian- and dose-dependent relationship in the use of antihypertensive drugs for the 24-h control of BP. In low- and middle-income areas, cost-effectiveness of any intervention is fundamental to the implementation of any kind of public-health policy. Therefore, improvements in diagnosis, effectiveness and implementing prevention measures to control the risk of disease are all necessary, and there is evidence that chronobiology has an important role to play. Consequently, it is important to provide guidelines to monitor BP to reduce cardiovascular risk that include chronobiological aspects of the problem

Ancestral sleep

While we do not yet understand all the functions of sleep, its critical role for normal physiology and behaviour is evident. Its amount and temporal pattern depend on species and condition. Humans sleep about a third of the day with the longest, consolidated episode during the night. The change in lifestyle from hunter-gatherers via agricultural communities to densely populated industrialized centres has certainly affected sleep, and a major concern in the medical community is the impact of insufficient sleep on health [1,2]. One of the causal mechanisms leading to insufficient sleep is altered exposure to the natural light-dark cycle. This includes the wide availability of electric light, attenuated exposure to daylight within buildings, and evening use of light-emitting devices, all of which decrease the strength of natural light-dark signals that entrain circadian systems [3].Fil: de la Iglesia, Daniel Horacio. University of Washington; Estados UnidosFil: Moreno, Claudia. Stockholms Universitet; Suecia. Universidade de Sao Paulo; Brasil. Stockholms Universitet; SueciaFil: Lowden, Arne. Stockholms Universitet; SueciaFil: Louzada, Fernando. Universidade Federal do Paraná; BrasilFil: Marqueze, Elaine. Universidade de Sao Paulo; Brasil. Universidade Católica de Santos; BrasilFil: Levandovski, Rosa. Universidade Federal do Rio Grande do Sul; BrasilFil: Pilz, Luisa K.. Universidade Federal do Rio Grande do Sul; Brasil. Ludwig Maximilians Universitat; AlemaniaFil: Valeggia, Claudia Rita. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Yale; Estados UnidosFil: Fernandez Duque, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Yale; Estados UnidosFil: Golombek, Diego Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Czeisler, Charles A.. Brigham and Women’s Hospital; Estados Unidos. Harvard Medical School; Estados UnidosFil: Skene, Debra J.. University of Surrey. Faculty of Health & Medical Sciences; Reino UnidoFil: Duffy, Jeanne F.. Brigham and Women’s Hospital; Estados Unidos. Harvard Medical School; Estados UnidosFil: Roenneberg, Till. Ludwig Maximilians Universitat; Alemani

The politics of the new history school textbooks in the Russian Federation

The chapter examines the ideologically articulated shifts, the images of transformation, and the nation-building process presented in the new generation of school history textbooks in Russia. It analyzes the new content of postSoviet history textbooks used in Russian secondary schools that represents various transformations from communism to a Western-style democracy. It discusses the resultant issues of searching for a new national identity and citizenship during the present transitional period. It critiques the new versions of Russia’s postSoviet history taught in schools, and evaluates their officially defined status as instruments in the Russian process of ideological transformation, and nation-building, currently closely monitored by the state. In other countries, including Australia, these processes are still present but in less formal and more ad hoc ways