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Circadian rhythms

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https://www.readbyqxmd.com/read/28927226/female-clock%C3%AE-19-%C3%AE-19-mice-are-protected-from-the-development-of-age-dependent-cardiomyopathy
#1
Faisal J Alibhai, Cristine J Reitz, Willem T Peppler, Poulami Basu, Paul Sheppard, Elena Choleris, Marica Bakovic, Tami A Martino
Aims: Circadian rhythms are important for healthy cardiovascular physiology and they are regulated by the molecular circadian mechanism. Previously, we showed that disruption of the circadian mechanism factor CLOCK in male Clock Δ19/Δ19 mice led to development of age-dependent cardiomyopathy. Here, we investigate the role of biological sex in protecting against heart disease in aging female Clock Δ19/Δ19 mice. Methods and results: Female Clock Δ19/Δ19 mice are protected from the development of cardiomyopathy with age, as heart structure and function are similar to 18 months of age versus female WT mice...
September 12, 2017: Cardiovascular Research
https://www.readbyqxmd.com/read/28926419/peduncular-hallucinosis-and-autonomic-dysfunction-in-anti-aquaporin-4-antibody-syndrome
#2
Renee Berry, Peter K Panegyres
Neuromyelitis optica is a rare, severe inflammatory demyelinating disease of the central nervous system, previously described as affecting only the optic nerve and spinal cord. Since the discovery of a highly specific autoantibody, anti-aquaporin-4, lesions are now recognized outside these regions. We report a man with severe, debilitating symptoms resulting from a symptomatic lesion within the diencephalon, manifesting with abnormal circadian rhythms, autonomic dysfunction, behavioral disturbance, and complex visual hallucinations...
September 2017: Cognitive and Behavioral Neurology: Official Journal of the Society for Behavioral and Cognitive Neurology
https://www.readbyqxmd.com/read/28920706/do-night-and-around-the-clock-firefighters-shift-schedules-induce-deviation-in-tau-from-24-hours-of-systolic-and-diastolic-blood-pressure-circadian-rhythms
#3
Alain E Reinberg, Michael H Smolensky, Marc Riedel, Cedric Riedel, Eric Brousse, Yvan Touitou
Systolic (S) and diastolic (D) blood pressures (BP) [SBP and DBP] are circadian rhythmic with period (τ) in healthy persons assumed to be maintained at 24.0h. We tested this assumption in a sample of 30 healthy career (mean >12 yrs) 30-to-46 yr-old male Caucasian French firefighters (FFs) categorized into three groups according to work schedule and duties: Group A - 12 FFs working 12h day, 12h night, and occasionally 24h shifts and whose primary duties are firefighting plus paramedical and road rescue services; Group B - 9 FFs working mostly 12h day and 12h night shifts and whose duties are answering incoming emergency calls and coordinating service vehicle dispatch from fire stations with Group A personnel; Group C - 9 day shift (09:00-17:00h) FFs charged with administrative tasks...
September 18, 2017: Chronobiology International
https://www.readbyqxmd.com/read/28916681/circannual-testis-and-moult-cycles-persist-under-photoperiods-that-disrupt-circadian-activity-and-clock-gene-cycles-in-spotted-munia
#4
Neha Agarwal, Ila Mishra, Ruchi Komal, Sangeeta Rani, Vinod Kumar
We investigated if circannual rhythms underlying annual testis maturation and moult cycles were independent of the duration and frequency of light period and the circadian clock control in non-photoperiodic spotted munia. Birds were subjected to an aberrant light-dark (LD) cycle (3.5L:3.5D; T7, T=period length of LD cycle) and continuous light (LL, 24L:0D), with controls on 12L:12D (T24, 24 h LD cycle). Initial experiment measured the activity pattern and 24 h mRNA oscillations of circadian clock genes (bmal1, clock, per2, cry1, cry2) in the hypothalamus, putative site of the seasonal timing...
September 15, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28914494/sketching-biological-phenomena-and-mechanisms
#5
Benjamin Sheredos, William Bechtel
In many fields of biology, both the phenomena to be explained and the mechanisms proposed to explain them are commonly presented in diagrams. Our interest is in how scientists construct such diagrams. Researchers begin with evidence, typically developed experimentally and presented in data graphs. To arrive at a robust diagram of the phenomenon or the mechanism, they must integrate a variety of data to construct a single, coherent representation. This process often begins as the researchers create a first sketch, and it continues over an extended period as they revise the sketch until they arrive at a diagram they find acceptable...
September 15, 2017: Topics in Cognitive Science
https://www.readbyqxmd.com/read/28912257/nurse-honeybee-workers-tend-capped-brood-which-does-not-require-feeding-around-the-clock
#6
Moshe Nagari, Yafit Brenner, Guy Bloch
"Nurse" honeybees tend brood around-the-clock with attenuated or no circadian rhythms, but the brood signals inducing this behavior remain elusive. We first tested the hypothesis that worker circadian rhythms are regulated by brood pheromones. We monitored locomotor activity of individually isolated nurse bees that were either exposed to various doses of larval extracts or synthetic brood ester pheromone (BEP). Bees orally treated with larvae extracts showed attenuated circadian rhythms in one of four tested colonies; a similar but statistically non-significant trend was seen in two additional colonies...
September 14, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28912161/disruption-of-bmal1-impairs-blood-brain-barrier-integrity-via-pericyte-dysfunction
#7
Ryota Nakazato, Kenji Kawabe, Daisuke Yamada, Shinsuke Ikeno, Michihiro Mieda, Shigeki Shimba, Eiichi Hinoi, Yukio Yoneda, Takeshi Takarada
Circadian rhythm disturbances are well-established in neurological diseases. However, how these disruptions cause homeostatic imbalances remains poorly understood. Brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein 1 (Bmal1) is a major circadian clock transcriptional activator, and Bmal1 deficiency in male Bmal1nestin(-/-) mice induced marked astroglial activation without affecting the number of astrocytes in the brain and spinal cord. Bmal1 deletion caused blood-brain barrier (BBB) hyperpermeability with an age-dependent loss of pericyte coverage of blood vessels in the brain...
September 14, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28912014/acute-alerting-effects-of-light-a-systematic-literature-review
#8
REVIEW
Jan L Souman, Angelica M Tinga, Susan F Te Pas, Raymond van Ee, Björn N S Vlaskamp
Periodic, well timed exposure to light is important for our health and wellbeing. Light, in particular in the blue part of the spectrum, is thought to affect alertness both indirectly, by modifying circadian rhythms, and directly, giving rise to acute effects. We performed a systematic review of empirical studies on direct, acute effects of light on alertness to evaluate the reliability of these effects and to assess to what extent they depend on other factors, such as time of day, exposure duration and sleep pressure...
September 11, 2017: Behavioural Brain Research
https://www.readbyqxmd.com/read/28911179/deciphering-the-function-of-the-blunt-circadian-rhythm-of-melatonin-in-the-newborn-lamb-impact-on-adrenal-and-heart
#9
Maria Seron-Ferre, Claudia Torres-Farfan, Francisco J Valenzuela, Sebastian Castillo-Galan, Auristela Rojas, Natalia Mendez, Henry Reynolds, Guillermo J Valenzuela, Anibal J Llanos
Neonatal lambs, as with human and other neonates, have low arrhythmic endogenous levels of melatonin for several weeks until they start their own pineal rhythm of melatonin production at approximately 2 weeks of life. During pregnancy, daily rhythmic transfer of maternal melatonin to the fetus has important physiological roles in sheep, nonhuman primates, and rats. This melatonin rhythm provides a circadian signal and also participates in adjusting the physiology of several organs in preparation for extrauterine life...
September 1, 2017: Endocrinology
https://www.readbyqxmd.com/read/28911138/resetting-the-abnormal-circadian-cortisol-rhythm-in-adrenal-incidentaloma-patients-with-mild-autonomous-cortisol-secretion
#10
Miguel Debono, Robert F Harrison, Rita Chadarevian, Carole Gueroult, Jean-Louis Abitbol, John Newell-Price
Context: Adrenal incidentalomas (AIs) are found commonly on axial imaging. Around 30% exhibit autonomous cortisol secretion (ACS) associated with increased cardiovascular events and death. Objective: We hypothesized that AI/ACS patients have an abnormal cortisol rhythm that could be reversed by use of carefully timed short-acting cortisol synthesis blockade, with improvement in cardiovascular disease markers. Design, Setting, and Participants: In a phase 1/2a, prospective study (Eudract no...
September 1, 2017: Journal of Clinical Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28910551/effects-of-differences-in-the-availability-of-light-upon-the-circadian-rhythms-of-institutionalized-elderly
#11
José A Rubiño, Antoni Gamundí, Mourad Akaarir, Francesca Cañellas, Rubén Rial, Neus Ballester, M Cristina Nicolau
The aim of this study was to compare the availability of diurnal and nocturnal light in two residences for aged persons (R1 and R2, Palma de Mallorca, Illes Balears, Spain). We found that the R1 inmates were exposed to lower amounts of light during waking time and higher amounts during sleeping time. The main traits of the circadian rhythms and the quality of sleep in the inmates of the two residences were found to be positively related to the availability of light during waking time and negatively to the increased light exposure during bed time...
September 14, 2017: Chronobiology International
https://www.readbyqxmd.com/read/28910547/diurnal-opposite-variation-between-angiotensinase-activities-in-photo-neuro-endocrine-tissues-of-rats
#12
Germán Domínguez-Vías, Garbiñe Aretxaga-Maza, Isabel Prieto, Juan de Dios Luna, Marc De Gasparo, Manuel Ramírez-Sánchez
Central and peripheral renin-angiotensin systems (RASs) act in a coordinated manner for the physiologic functions regulated by neuroendocrine events. However, whereas the diurnal rhythm of peripheral circulatory and tissue RASs is well known, the circadian behaviour of their components in central photo-neuro-endocrine structures, key elements for the control of circadian rhythms, has been barely studied. In the present study, we analysed the aspartyl- (AspAP) and glutamyl-aminopeptidase (GluAP) (aminopeptidase A) activities, the angiotensinases responsible for the metabolism of Ang I to Ang 2-10 and Ang II to Ang III, respectively, in the retina, anterior hypothalamus and pituitary at different light and dark time-points of a 12:12 h light:dark cycle (7-19 h light), using arylamide derivatives as substrates...
September 14, 2017: Chronobiology International
https://www.readbyqxmd.com/read/28910542/effect-of-monochromatic-light-on-circadian-rhythmic-expression-of-clock-genes-and-arylalkylamine-n-acetyltransferase-in-chick-retina
#13
Jing Cao, Jiang Bian, Zixu Wang, Yulan Dong, Yaoxing Chen
Birds have more developed visual function. They not only have the ability to detect light and darkness but also have the color vision. Previous study showed that monochromatic light influenced avian physiological processes, which were controlled by clock genes. Therefore, bird's eye is a good model to studying the impact of color of light on circadian rhythms. Avian retina is one of the most important central oscillations. The study was designed to investigate the effect of color of light on the expression of clock genes and arylalkylamine N-acetyltransferase (Aanat) mRNA expression in chick retina...
September 14, 2017: Chronobiology International
https://www.readbyqxmd.com/read/28905851/increased-double-product-on-monday-morning-during-work
#14
Genjiro Kimura, Nobutaka Inoue, Hiroumi Mizuno, Masaaki Izumi, Katsuyuki Nagatoya, Akira Ohtahara, Masanori Munakata
It has been reported that cardiovascular events often occur on Monday morning, especially in the young working population. Because hypertension is a major cardiovascular risk, we examined whether blood pressure was elevated on Monday, especially in the morning during work. However, there were no weekly rhythms in blood pressure itself. Instead, we found significant interactions between the double product (systolic blood pressure × heart rate) and weekly (high on Monday) and circadian (high in the morning) rhythms...
July 2017: Hypertension Research: Official Journal of the Japanese Society of Hypertension
https://www.readbyqxmd.com/read/28905326/circadian-rhythms-sleep-and-cognitive-skills-evidence-from-an-unsleeping-giant
#15
Osea Giuntella, Wei Han, Fabrizio Mazzonna
This study analyzes the effects of sleep duration on cognitive skills and depression symptoms of older workers in urban China. Cognitive skills and mental health have been associated with sleep duration and are known to be strongly related to economic behavior and performance. However, causal evidence is lacking, and little is known about sleep deprivation in developing countries. We exploit the relationship between circadian rhythms and bedtime to identify the effects of sleep using sunset time as an instrument...
September 13, 2017: Demography
https://www.readbyqxmd.com/read/28903391/cancer-testis-antigen-piwil2-suppresses-circadian-rhythms-by-regulating-the-stability-and-activity-of-bmal1-and-clock
#16
Yilu Lu, Xulei Zheng, Wei Hu, Shasha Bian, Zhiwei Zhang, Dachang Tao, Yunqiang Liu, Yongxin Ma
Circadian rhythms are regulated by transcriptional and post-translational feedback loops generated by appropriate functions of clock proteins. Rhythmic degradation of the circadian clock proteins is critical for maintenance of the circadian oscillations. Notably, circadian clock does not work during spermatogenesis and can be disrupted in tumors. However, the underlying mechanism that suppresses circadian rhythms in germ cells and cancer cells remains largely unknown. Here we report that the cancer/testis antigen PIWIL2 can repress circadian rhythms both in the testis and cancer cells...
August 15, 2017: Oncotarget
https://www.readbyqxmd.com/read/28902457/the-role-of-clock-gene-in-psychiatric-disorders-evidence-from-human-and-animal-research
#17
REVIEW
Jaqueline B Schuch, Julia P Genro, Clarissa R Bastos, Gabriele Ghisleni, Luciana Tovo-Rodrigues
The circadian clock system drives daily rhythms in physiology, metabolism, and behavior in mammals. Molecular mechanisms of this system consist of multiple clock genes, with Circadian Locomotor Output Cycles Kaput (CLOCK) as a core member that plays an important role in a wide range of behaviors. Alterations in the CLOCK gene are associated with common psychiatric disorders as well as with circadian disturbances comorbidities. This review addresses animal, molecular, and genetic studies evaluating the role of the CLOCK gene on many psychiatric conditions, namely autism spectrum disorder, schizophrenia, attention-deficit/hyperactivity disorder, major depressive disorder, bipolar disorder, anxiety disorder, and substance use disorder...
September 13, 2017: American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics
https://www.readbyqxmd.com/read/28900189/misalignment-with-the-external-light-environment-drives-metabolic-and-cardiac-dysfunction
#18
Alexander C West, Laura Smith, David W Ray, Andrew S I Loudon, Timothy M Brown, David A Bechtold
Most organisms use internal biological clocks to match behavioural and physiological processes to specific phases of the day-night cycle. Central to this is the synchronisation of internal processes across multiple organ systems. Environmental desynchrony (e.g. shift work) profoundly impacts human health, increasing cardiovascular disease and diabetes risk, yet the underlying mechanisms remain unclear. Here, we characterise the impact of desynchrony between the internal clock and the external light-dark (LD) cycle on mammalian physiology...
September 12, 2017: Nature Communications
https://www.readbyqxmd.com/read/28899666/stem-cells-and-the-circadian-clock
#19
REVIEW
Meltem Weger, Nicolas Diotel, Anne-Claire Dorsemans, Thomas Dickmeis, Benjamin D Weger
The circadian timing system is a complex biological network of interacting circadian clocks that regulates 24h rhythms of behavioral and physiological processes. One intriguing observation is that stem cell homeostasis is subject to circadian clock regulation. Rhythmic oscillations have been observed in a variety of embryonic and adult stem cell dependent processes, such as hematopoietic progenitor cell migration, the hair follicle cycle, bone remodeling, regenerative myogenesis and neurogenesis. This review aims to discuss the nature of the circadian clock in embryonic stem cells and how it changes during differentiation...
September 9, 2017: Developmental Biology
https://www.readbyqxmd.com/read/28899534/gene-by-environment-interactions-of-the-clock-pemt-and-ghrelin%C3%A2-loci-with-average-sleep-duration-in-relation-to-obesity-traits%C3%A2-using-a-cohort-of-643-new-zealand-european-children
#20
Mohanraj Krishnan, Andrew N Shelling, Clare R Wall, Edwin A Mitchell, Rinki Murphy, Lesley M E McCowan, John M D Thompson
OBJECTIVES: Modern technology may have desensitised the 'biological clock' to environmental cues, disrupting the appropriate co-ordination of metabolic processes. Susceptibility to misalignment of circadian rhythms may be partly genetically influenced and effects on sleep quality and duration could predispose to poorer health outcomes. Shorter sleep duration is associated with obesity traits, which are brought on by an increased opportunity to eat and/or a shift of hormonal profile promoting hunger...
September 2017: Sleep Medicine
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