Chronobiology international
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It has frequently been reported that exposure to artificial light at night (ALAN) may cause negative health effects, such as breast cancer, circadian phase disruption and sleep disorders. Here, we reviewed the literature assessing the effects of human exposure to ALAN in order to list the health effects of various aspects of ALAN. Several electronic databases were searched for articles, published through August 2014, related to assessing the effects of exposure to ALAN on human health; these also included the details of experiments on such exposure. ⋯ ALAN also causes circadian phase disruption, which increases with longer duration of exposure and with exposure later in the evening. It has also been reported that shorter wavelengths of light preferentially disturb melatonin secretion and cause circadian phase shifts, even if the light is not bright. This literature review may be helpful to understand the health effects of ALAN exposure and suggests that it is necessary to consider various characteristics of artificial light, beyond mere intensity.
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Diagnosed cardiovascular disease has well-reported temporal patterns, with demand distribution peaks in the late morning and greater case numbers on Mondays and in winter. We aimed to report temporal patterns of presumptive cardiovascular disease cases as determined after emergency medical services (EMS) assessment and to characterize the demand distribution by day of the week. We conducted a secondary analysis of all Ambulance Victoria cases in metropolitan Melbourne (Victoria, Australia) between January 2008 and December 2011. ⋯ We have shown that examination of presumptive cardiovascular disease using not only case counts but also demand distribution patterns allows for a greater understanding of ambulance demand. Monday might be the most frequent day for cardiovascular cases but different patterns of demand occur on weekends. Increased knowledge of when different types of cases are most likely to occur will help inform EMS planning, including paramedic capacity and resources.
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The purpose of this pilot study was to explore the utility of the mammalian swine model under simulated intensive care unit (sICU) conditions and mechanical ventilation (MV) for assessment of the trajectory of circadian rhythms of sedation requirement, core body temperature (CBT), pulmonary mechanics (PM) and gas exchange (GE). Data were collected prospectively with an observational time-series design to describe and compare circadian rhythms of selected study variables in four swine mechanically ventilated for up to seven consecutive days. We derived the circadian (total variance explained by rhythms of τ between 20 and 28 h)/ultradian (total variance explained by rhythms of τ between 1 and <20 h) bandpower ratio to assess the robustness of circadian rhythms, and compare findings between the early (first 3 days) and late (subsequent days) sICU stay. ⋯ Individual subject observations were more informative than group data, and provided preliminary evidence that (a) circadian rhythms of multiple variables are lost or desynchronized in mechanically ventilated subjects, (b) robustness of circadian rhythm varies with subject morbidity and (c) healthier pigs develop more robust circadian rhythm profiles over time in the sICU. Comparison of biological rhythm profiles among sICU subjects with similar severity of illness is needed to determine if the results of this pilot study are reproducible. Identification of consistent patterns may provide insight into subject morbidity and timing of such therapeutic interventions as weaning from MV.
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Genes involved in circadian regulation, such as circadian locomotor output cycles kaput [CLOCK], cryptochrome [CRY1] and period [PER], have been associated with sleep outcomes in prior animal and human research. However, it is unclear whether polymorphisms in these genes are associated with the sleep disturbances commonly experienced by adults living with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS). Thus, the purpose of this study was to describe polymorphisms in selected circadian genes that are associated with sleep duration or disruption as well as the sleep-wake rhythm strength and phase timing among adults living with HIV/AIDS. ⋯ In this chronic illness population, polymorphisms in several circadian genes were associated with measures of sleep disruption and timing. These findings extend the evidence for an association between genetic variability in circadian regulation and sleep outcomes to include the sleep-wake patterns experienced by adults living with HIV/AIDS. These results provide direction for future intervention research related to circadian sleep-wake behavior patterns.
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Simultaneous analysis of the transcripts of thousands of genes by cDNA microarrays allows the identification of genetic regulatory mechanisms involved in disease pathophysiology. The circadian clock circuitry controls essential cell processes and the functioning of organ systems, which are characterized by rhythmic variations with 24-hour periodicity. The derangement of these processes is involved in the basic mechanisms of inflammatory, metabolic, degenerative and neoplastic diseases. ⋯ Conversely, ARNTL2, CRY1, CSNK1E, RORA and TIPIN were up-regulated, while NR1D2 and PER3 were down-regulated in UC. In conclusion, in CD and UC patients there are differences in the expression of circadian genes between normal and diseased intestinal mucosa. The deregulated genes evidenced by transcriptome analysis in the major IBDs may play a crucial role in the pathophysiological mechanisms and may suggest novel therapeutic approaches.