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Journal of Circadian Rhythms

Sajad Zare, Hossein Elahi Shirvan, Rasoul Hemmatjo, Mohammad Faridan, Masoud Hajghani, Behzad Fouladi Dehaghi
Introduction: Increasing population, the need for services, and industrialization of societies have led to a growing demand for shift work. Shiftwork causes several disorders, and determining the weight of each disorders is important for their prevention and treatment. Therefore, the purpose of the present study was to use Analytic Network Process (ANP) to prioritize and weigh shift work disorders among the personnel of hospitals of Kerman University of Medical Sciences. Methods: This cross-sectional, descriptive-analytical study was conducted in 2017 among 300 shift work personnel of 10 public hospitals affiliated with Kerman University of Medical Sciences...
October 4, 2018: Journal of Circadian Rhythms
Taleb Askaripoor, Majid Motamedzadeh, Rostam Golmohammadi, Maryam Farhadian, Mohammad Babamiri, Mehdi Samavati
Fatigue and sleepiness are one of the main causes of human errors and accidents in the workplace. The empirical evidence has approved that, in addition to stimulating the visual system, light elicits brain responses, which affect physiological and neurobehavioral human functions, known as the non-image forming (NIF) effects of light. As recent evidences have shown the positive effects of red or low correlated color temperature white light on alertness and performance, we investigated whether exposure to 2564 K light could improve subjective and objective measures of alertness and performance compared with 7343 K, 3730 K, and dim light (DL) conditions during the daytime...
September 12, 2018: Journal of Circadian Rhythms
Austin Anderson, Gillian Murray, Meaghan Herlihy, Chloe Weiss, Jacob King, Ellen Hutchinson, Neil Albert, Krista K Ingram
Although individual athletic performance generally tends to peak in the evening, individuals who exhibit a strong diurnal preference perform better closer to their circadian peak. Time-of-day performance effects are influenced by circadian phenotype (diurnal preference and chronotype-sleep-wake patterns), homeostatic energy reserves and, potentially, genotype, yet little is known about how these factors influence physiological effort. Here, we investigate the effects of time of day, diurnal preference, chronotype, and PER3 (a circadian clock gene) genotype on both effort and performance in a population of Division I collegiate swimmers (n = 27)...
August 3, 2018: Journal of Circadian Rhythms
Isabella M Hower, Sara A Harper, Thomas W Buford
Human circadian rhythmicity is driven by a circadian clock comprised of two distinct components: the central clock, located in the suprachiasmatic nucleus (SCN) within the hypothalamus, and the peripheral clocks, located in almost all tissues and organ systems in the body. Entrainment, or alignment, of circadian rhythmicity is dependent upon time of day and can occur through environmental influences such as light cues and physical activity exerted on skeletal muscle. Entrainment of the circadian clock through exercise has been reported to improve health by reducing risk of conditions such as cardiovascular disease (CVD), but further research is still needed...
July 12, 2018: Journal of Circadian Rhythms
Abdullah Mashhour, Zainab Al Mansour, Al Shaima Al Hallaj, Rizwan Ali, Thadeo Trivilegio, Mohamed Boudjelal
In mammals, circadian rhythmicity is sustained via a transcriptional/translational feedback loop referred to as the canonical molecular circadian clock. Circadian rhythm is absent in undifferentiated embryonic stem cells; it begins only after differentiation. We used pluripotent P19 embryonal carcinoma stem cells to check the biological clock before and after differentiation into neurons using retinoic acid. We show that the central clock genes ARNTL (Bmal), Per2 and Per3 , and the peripheral clock genes Rev-erb-α and ROR-α , oscillate before and after differentiation, as does the expression of the neuronal differentiation markers Hes5 , β-3-tubulin (Tubb3) and Stra13 , but not Neurod1 ...
May 18, 2018: Journal of Circadian Rhythms
Hiroshi Kawai, Natsumi Kodaira, Chika Tanaka, Takuya Ishibashi, Naomi Kudo, Yoichi Kawashima, Atsushi Mitsumoto
The pathogenesis and therapeutics of depression are linked to the operation of the circadian system. Here, we studied the chronopharmacological action of a tricyclic antidepressant, imipramine. Male adult Wistar-Hannover rats were administered imipramine acutely or chronically in the morning or in the evening. The antidepressant action of imipramine was analyzed using the forced swim test (FST). A single dose of imipramine (30 mg/kg) in the morning, but not in the evening, reduced immobility and increased climbing in the FST...
May 10, 2018: Journal of Circadian Rhythms
Ramanujam Karthikeyan, David Warren Spence, Gregory M Brown, Seithikurippu R Pandi-Perumal
In recent years, there has been an increased prevalence of type 2 diabetes mellitus (T2DM) and depression across the world. This growing public health problem has produced an increasing socioeconomic burden to the populations of all affected countries. Despite an awareness by public health officials and medical researchers of the costs associated with these diseases, there still remain many aspects of how they develop that are not understood. In this article, we propose that the circadian clock could be a factor that coordinates both the neurobehavioral and metabolic processes that underlie depression and T2DM...
April 18, 2018: Journal of Circadian Rhythms
Karyn Geralyn Butler
Affective disorders impact women's health, with a lifetime prevalence of over twelve per cent. They have been correlated with reproductive cycle factors, under the regulation of hormonal circadian rhythms. In affective disorders, circadian rhythms may become desynchronized. The circadian rhythms of cortisol and estradiol may play a role in affective disorders. The purpose of this study was to explore the temporal relationship between the rhythms of cortisol and estradiol and its relationship to affect. It was hypothesized that a cortisol-estradiol phase difference (PD) exists that correlates with optimal affect...
February 21, 2018: Journal of Circadian Rhythms
Mathias Adamsson, Thorbjörn Laike, Takeshi Morita
The purpose of the study was to investigate seasonal variation in mood and behavior among a group of office workers in Sweden (56°N). Thirty subjects participated in this longitudinal study. The subjects kept a weekly log that included questionnaires for ratings of psychological wellbeing and daily sleep-activity diaries where they also noted time spent outdoors. The lighting conditions in the offices were subjectively evaluated during one day, five times over the year. There was a seasonal variation in positive affect and in sleep-activity behavior...
February 21, 2018: Journal of Circadian Rhythms
Reza Kazemi, Sajad Zare, Rasoul Hemmatjo
Introduction: A two-shift work schedule with different rotations is common among firefighters in Iranian petrochemical companies. This study compared salivary melatonin and sleepiness on the last night before turning to day shift at 19:00, 23:00, 3:00, and 7:00 among petrochemical firefighters (PFFs) working seven and four consecutive night shifts. Methods: Sixty four PFFs working in the petrochemical industry were selected. To measure melatonin, saliva samples were taken, whereas the KSS index was used to assess sleepiness...
February 21, 2018: Journal of Circadian Rhythms
Juri Olkkonen, Vesa-Petteri Kouri, Elina Kuusela, Mari Ainola, Dan Nordström, Kari K Eklund, Jami Mandelin
The expression of clock genes ARNTL2, NPAS2 and DEC2 are disturbed in rheumatoid arthritis, an autoimmune disease with circadian variation of symptoms. We have shown that TNF is a potent inducer of these genes. We investigated the regulation of ARNTL2 and NPAS2 by TNF and elucidated their effect on other clock gene expressions. Additionally, we studied the effect of DEC1 and DEC2 on ARNTL, ARNTL2 and NPAS2 . Cultured primary human fibroblasts were stimulated with TNF and the effects on ARNTL2 and NPAS2 were studied with RT-qPCR and immunofluorescence staining...
August 11, 2017: Journal of Circadian Rhythms
Harold Kuta Makeri, Joseph Olusegun Ayo, Tagang Aluwong, Ndazo Salka Minka
Several studies carried out on humans and other mammals show that the temporal organisation of haematological parameters in the blood exhibit daily rhythms; however, such studies have been rare in poultry reared under a natural photoperiod. The present study investigated the occurrence of daily rhythms in blood parameters of broiler chickens kept under tropical climatic conditions. Ten 6-7-week-old broiler chickens served as subjects of the study. They were kept in standard individual cages under natural light-dark cycle and given access to feed and water ad libitum ...
August 10, 2017: Journal of Circadian Rhythms
Isaac Chayo, Mercedes Fernandez, Samantha Sandor, Jaime L Tartar
Previous work from our laboratory has shown that a measure of attention to emotionally-charged stimuli, the late positive potential (LPP) event related potential (ERP), distinguished neutral from emotional pictures on a baseline day, but not after sleep deprivation. Here we sought to extend these findings and address the uncertainty about the effect of time-of-day on emotion processing by testing a morning group (8:00-10:00 a.m., n = 30) and an evening group (8:00-10:00 p.m., n = 30). We also examined the extent of diurnal changes in cortisol related to the emotion processing task...
May 23, 2017: Journal of Circadian Rhythms
Sabhi Rahman, Al-Shaimaa Al-Hallaj, Atef Nedhi, Gmal Gmati, Khadega Ahmed, Haya Al Jama, Thadeo Trivilegio, Abdullah Mashour, Ahmad Al Askar, Mohamed Boudjelal
Disregulation of genes making up the mammalian circadian clock has been associated with different forms of cancer. This study aimed to address how the circadian clock genes behave over the course of treatment for both the acute and chronic forms of leukemia and whether any could be used as potential biomarkers as a read-out for therapeutic efficacy. Expression profiling for both core and ancillary clock genes revealed that the majority of clock genes are down-regulated in acute myeloid leukemia patients, except for Cry2, which is up-regulated towards the end of treatment...
April 28, 2017: Journal of Circadian Rhythms
Ray Norbury
Bibliometric indices are a widely used measure of research impact. The aim of the current study was to identify and characterise the top one hundred most-cited research articles in the topic of chronotype research. A search of the Thomson Reuters Web of Science database returned 974 eligible articles (published between 1990 and 2016). Citations for the 100 most-cited articles ranged between 438 and 29. The most represented journal was Chronobiology International ( n = 30). Nearly 50% of articles originated in Germany and the U...
January 27, 2017: Journal of Circadian Rhythms
Manuel Miranda-Anaya, Dalia Luna-Moreno, Agustín Carmona-Castro, Mauricio Díaz-Muñoz
Obesity is a growing problem worldwide with a clear impact on health status. It is also a condition that negatively affects circadian rhythms. When the mouse Neotomodon alstoni is fed a regular rodent chow, some individuals develop obesity, representing an opportunity to compare the effects of spontaneous obesity upon the circadian organization in this species with that observed in other rodents with induced obesity. We report differences in the free running circadian locomotor activity rhythm and in the effects of light pulses between lean and obese mice...
January 27, 2017: Journal of Circadian Rhythms
Ndazo S Minka, Joseph O Ayo
Studies on daily rhythmicity in livestock under natural conditions are limited, and there is mounting evidence that rhythm patterns differ between chronobiological studies conducted in the laboratory and studies conducted under pronounced natural seasonality. Here, we investigated the influence of cold-dry (harmattan) and hot-dry seasons on daily rhythmicity of rectal (RT) and body surface temperatures (BST) in indigenous sheep and goats under natural light-dark cycles. The RT and BST of the animals, and the ambient temperature (AT) and relative humidity (RH) inside the pen, were measured every three hours for a period of two days, twice on separate days during the hot-dry and the harmattan seasons, respectively...
November 29, 2016: Journal of Circadian Rhythms
Dale L Clayton
Data presented in this paper test the hypotheses that Hirsch's positive geotaxis (Lo) and negative geotaxis (Hi5) strains of Drosophila melanogaster (fruit fly) differ in length of the free-running circadian activity period (tau) as well as adult geotaxis. Several genes have been shown to alter geotaxis in Drosophila . Two of these genes, cryptochrome (cry) and Pigment-dispersing-factor (Pdf) are integral to the function of biological clocks. Pdf plays a crucial role in maintaining free-running circadian periods...
June 24, 2016: Journal of Circadian Rhythms
Tatiana D Viena, Christina M Gobin, Ana I Fins, Travis J A Craddock, Aurélien Tartar, Jaime L Tartar
BACKGROUND: Expression of the clock family of genes in the suprachiasmatic nuclei (SCN) regulates the molecular control of circadian timing. Increasing evidence also implicates clock gene activity in the development of mood disorders. In particular, variation in the PER3 clock gene has been shown to influence diurnal preference and sleep homeostasis. However, there is not currently a clear association between PER3 polymorphisms and mood. This is possibly because the PER3 gene has been shown to influence homeostatic sleep drive, rather than circadian timing, and the PER3 gene may be behaviorally relevant only under chronic sleep loss conditions...
March 10, 2016: Journal of Circadian Rhythms
Shawn D Youngstedt, Christopher E Kline, Jeffrey A Elliott, Mark R Zielinski, Tina M Devlin, Teresa A Moore
Limited research has compared the circadian phase-shifting effects of bright light and exercise and additive effects of these stimuli. The aim of this study was to compare the phase-delaying effects of late night bright light, late night exercise, and late evening bright light followed by early morning exercise. In a within-subjects, counterbalanced design, 6 young adults completed each of three 2.5-day protocols. Participants followed a 3-h ultra-short sleep-wake cycle, involving wakefulness in dim light for 2h, followed by attempted sleep in darkness for 1 h, repeated throughout each protocol...
February 26, 2016: Journal of Circadian Rhythms
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