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2.
Nat Neurosci ; 23(3): 456-467, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32066983

RESUMEN

Mammalian circadian behaviors are orchestrated by the suprachiasmatic nucleus (SCN) in the ventral hypothalamus, but the number of SCN cell types and their functional roles remain unclear. We have used single-cell RNA-sequencing to identify the basic cell types in the mouse SCN and to characterize their circadian and light-induced gene expression patterns. We identified eight major cell types, with each type displaying a specific pattern of circadian gene expression. Five SCN neuronal subtypes, each with specific combinations of markers, differ in their spatial distribution, circadian rhythmicity and light responsiveness. Through a complete three-dimensional reconstruction of the mouse SCN at single-cell resolution, we obtained a standardized SCN atlas containing the spatial distribution of these subtypes and gene expression. Furthermore, we observed heterogeneous circadian gene expression between SCN neuron subtypes. Such a spatiotemporal pattern of gene regulation within the SCN may have an important function in the circadian pacemaker.


Asunto(s)
Expresión Génica/fisiología , Neuronas/fisiología , Análisis de la Célula Individual , Núcleo Supraquiasmático/fisiología , Animales , Atlas como Asunto , Ritmo Circadiano/fisiología , Péptidos y Proteínas de Señalización del Ritmo Circadiano/genética , Expresión Génica/efectos de la radiación , Regulación de la Expresión Génica/fisiología , Genómica , Luz , Masculino , Ratones , Ratones Endogámicos C57BL , Neuronas/clasificación , Estimulación Luminosa , Núcleo Supraquiasmático/anatomía & histología , Núcleo Supraquiasmático/citología
3.
Braz. J. Psychiatry (São Paulo, 1999, Impr.) ; 42(1): 68-71, Jan.-Feb. 2020. tab, graf
Artículo en Inglés | LILACS | ID: biblio-1055368

RESUMEN

Objective: Circadian dysregulation plays an important role in the etiology of mood disorders. Evening chronotype is frequent in these patients. However, prospective studies about the influence of chronotype on mood symptoms have reached unclear conclusions in patients with bipolar disorder (BD). The objective of this study was to investigate relationship between chronotype and prognostic factors for BD. Methods: At the baseline, 80 euthymic BD patients answered a demographic questionnaire and clinical scales to evaluate anxiety, functioning and chronotype. Circadian preference was measured using the Morningness-Eveningness Questionnaire, in which lower scores indicate eveningness. Mood episodes and hospitalizations were evaluated monthly for 18 months. Results: Among the BD patients, 14 (17.5%) were definitely morning type, 35 (43.8%), moderately morning, 27 (33.7%) intermediate (neither) and 4 (5%) moderately evening. Eveningness was associated with obesity or overweight (p = 0.03), greater anxiety (p = 0.002) and better functioning (p = 0.01), as well as with mood episodes (p = 0.04), but not with psychiatric hospitalizations (p = 0.82). This group tended toward depressive episodes (p = 0.06), but not (hypo)mania (p = 0.56). Conclusion: This study indicated that evening chronotype predicts a poor prognostic for BD. It reinforces the relevance of treating rhythm disruptions even during euthymia to improve patient quality of life and prevent mood episodes.


Asunto(s)
Humanos , Masculino , Femenino , Adulto , Anciano , Adulto Joven , Ansiedad/fisiopatología , Trastorno Bipolar/fisiopatología , Ritmo Circadiano/fisiología , Pronóstico , Escalas de Valoración Psiquiátrica , Calidad de Vida , Factores de Tiempo , Modelos Logísticos , Estudios Prospectivos , Encuestas y Cuestionarios , Estadísticas no Paramétricas , Trastornos Cronobiológicos/fisiopatología , Hospitalización/estadística & datos numéricos , Persona de Mediana Edad
4.
Medicine (Baltimore) ; 99(8): e19278, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32080140

RESUMEN

To investigate whether the control of morning blood pressure (MBP) reflects the control of blood pressure (BP) in other periods (daytime, nighttime and 24-hour) and to assess whether morning BP displays a closer association with subclinical target organ damage (TOD) than the BP measured in other periods.One thousand one hundred forty patients with primary hypertension who completed subclinical TOD detection and 24-hour ambulatory BP monitoring were included in the analysis. Pearson correlation analysis, Kappa consistency test, multiple linear regression analysis, and area under the receiver operating curve were used to analyze the data.Morning BP and daytime BP displayed good agreement, but not 24-hour BP , particularly the nighttime BP (all P < .001). Approximately 39.4% of the hypertensive patients receiving drug treatment who had achieved control of the morning BP presented masked nocturnal hypertension, which was associated with worse subclinical TOD. The BP measured in all periods correlated with subclinical TOD, and the correlation was more obvious in the treatment subgroup. However, morning BP did not independently affect subclinical TOD. Morning BP appeared to exhibit less discriminatory power than nighttime BP, particularly with respect to the urinary albumin to creatinine ratio.The use of morning BP for monitoring during hypertension management may not be enough. Masked uncontrolled nocturnal hypertension should be screened when morning BP is controlled.


Asunto(s)
Monitoreo Ambulatorio de la Presión Arterial , Ritmo Circadiano/fisiología , Hipertensión/fisiopatología , Hipertensión Enmascarada/diagnóstico , Albuminuria , Antihipertensivos/uso terapéutico , Grosor Intima-Media Carotídeo , Creatinina/orina , Estudios Transversales , Ecocardiografía , Femenino , Ventrículos Cardíacos/diagnóstico por imagen , Humanos , Hipertensión/tratamiento farmacológico , Masculino , Hipertensión Enmascarada/fisiopatología , Persona de Mediana Edad
5.
PLoS Biol ; 18(2): e3000602, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-32069275

RESUMEN

The brain exhibits substantial diurnal variation in physiology and function, but neuroscience studies rarely report or consider the effects of time of day. Here, we examined variation in resting-state functional MRI (fMRI) in around 900 individuals scanned between 8 AM and 10 PM on two different days. Multiple studies across animals and humans have demonstrated that the brain's global signal (GS) amplitude (henceforth referred to as "fluctuation") increases with decreased arousal. Thus, in accord with known circadian variation in arousal, we hypothesised that GS fluctuation would be lowest in the morning, increase in the midafternoon, and dip in the early evening. Instead, we observed a cumulative decrease in GS fluctuation as the day progressed. Although respiratory variation also decreased with time of day, control analyses suggested that this did not account for the reduction in GS fluctuation. Finally, time of day was associated with marked decreases in resting-state functional connectivity across the whole brain. The magnitude of decrease was significantly stronger than associations between functional connectivity and behaviour (e.g., fluid intelligence). These findings reveal time of day effects on global brain activity that are not easily explained by expected arousal state or physiological artefacts. We conclude by discussing potential mechanisms for the observed diurnal variation in resting brain activity and the importance of accounting for time of day in future studies.


Asunto(s)
Encéfalo/diagnóstico por imagen , Encéfalo/fisiología , Ritmo Circadiano/fisiología , Nivel de Alerta/fisiología , Artefactos , Mapeo Encefálico , Humanos , Imagen por Resonancia Magnética , Descanso/fisiología , Tiempo
6.
PLoS Biol ; 18(2): e3000622, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-32108181

RESUMEN

Circadian (daily) regulation of metabolic pathways implies that food may be metabolized differentially over the daily cycle. To test that hypothesis, we monitored the metabolism of older subjects in a whole-room respiratory chamber over two separate 56-h sessions in a random crossover design. In one session, one of the 3 daily meals was presented as breakfast, whereas in the other session, a nutritionally equivalent meal was presented as a late-evening snack. The duration of the overnight fast was the same for both sessions. Whereas the two sessions did not differ in overall energy expenditure, the respiratory exchange ratio (RER) was different during sleep between the two sessions. Unexpectedly, this difference in RER due to daily meal timing was not due to daily differences in physical activity, sleep disruption, or core body temperature (CBT). Rather, we found that the daily timing of nutrient availability coupled with daily/circadian control of metabolism drives a switch in substrate preference such that the late-evening Snack Session resulted in significantly lower lipid oxidation (LO) compared to the Breakfast Session. Therefore, the timing of meals during the day/night cycle affects how ingested food is oxidized or stored in humans, with important implications for optimal eating habits.


Asunto(s)
Ritmo Circadiano/fisiología , Metabolismo de los Lípidos/fisiología , Comidas/fisiología , Índice de Masa Corporal , Desayuno , Metabolismo de los Hidratos de Carbono/fisiología , Estudios Cruzados , Conducta Alimentaria/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Oxidación-Reducción , Intercambio Gaseoso Pulmonar/fisiología , Sueño/fisiología , Bocadillos
7.
Invest Ophthalmol Vis Sci ; 61(2): 37, 2020 02 07.
Artículo en Inglés | MEDLINE | ID: mdl-32097479

RESUMEN

Purpose: Recent retrospective clinical studies and animal experiments have suggested that cerebrospinal fluid pressure (CSFP) is important in glaucoma pathogenesis. Intraocular pressure (IOP) and CSFP are the driving components of the translaminar pressure (TLP), which directly effects the optic nerve head. This study measured the diurnal cycle of TLP using continuous wireless telemetry in nonhuman primates (NHPs), a common animal model of glaucoma. Methods: We have developed an implantable wireless telemetry system based on a small piezoelectric pressure transducer with low drift. Unilateral IOP was measured in the anterior chamber of the eye, and intracranial pressure (ICP, a surrogate measure of CSFP) was measured in the brain parenchyma in four awake, behaving NHPs for periods of 22 to 281 days. IOP and ICP telemetry transducers were calibrated with direct pressure measurements in the eye (every 2 weeks) and brain (monthly). TLP was quantified in real time as IOP-ICP, and hourly means of IOP, ICP, and TLP were analyzed. Results: Results show that mean ICP is significantly higher by an average of 4.8 ± 0.8 mmHg during sleeping hours in NHPs (P < 0.01). IOP showed a small but significant nocturnal elevation in two of four animals despite NHPs sleeping upright (P < 0.05). TLP was significantly lower during sleep (7.1 ± 0.6 mmHg; P < 0.01) than when the animals were awake and active (11.0 ± 0.9 mmHg), driven primarily by the large increase in ICP during sleep. Conclusions: The 56% increase in TLP during waking hours in NHPs matches the increase in TLP due to postural change from supine to upright reported previously in humans.


Asunto(s)
Cámara Anterior/fisiología , Ritmo Circadiano/fisiología , Glaucoma/fisiopatología , Presión Intracraneal/fisiología , Presión Intraocular/fisiología , Animales , Macaca mulatta , Masculino , Estudios Retrospectivos , Telemetría/métodos
8.
Nat Rev Endocrinol ; 16(4): 213-223, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32055029

RESUMEN

Meal timing and composition are frequently reported in the literature as zeitgebers (that is, time cues) for the circadian system of humans and animal models, albeit secondary to light. Although widely assumed to be true, evidence for food zeitgeber effects specific to humans is notably scarce. Fostering zeitgeber hygiene in the general population as the development and practice of healthy use of zeitgebers could potentially reduce chronobiological strain, which is defined as disruption or misalignment within the circadian system. Such chronobiological strain is associated with modern 24/7 lifestyles (for example, shift work) and several negative health outcomes. Adjustments to meal timing and composition are an attractive strategy to synchronize circadian rhythms and develop zeitgeber hygiene. Thus, clarifying the actual effect of meal timing and composition on the human circadian system is a crucial piece of the human chronobiology puzzle. This Review weighs the evidence from human studies pertaining to the hypothesis that food is a circadian zeitgeber by comparing findings against formal zeitgeber criteria put forward by Jürgen Aschoff in the 1950s.


Asunto(s)
Conducta Alimentaria/fisiología , Ritmo Circadiano/fisiología , Dieta , Femenino , Humanos , Masculino , Factores de Tiempo
9.
Cell Mol Life Sci ; 77(5): 875-884, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31982933

RESUMEN

The mechanisms that synchronize the biorhythms of the mammalian retina with the light/dark cycle are independent of those synchronizing the rhythms in the central pacemaker, the suprachiasmatic nucleus. The identity of the photoreceptor(s) responsible for the light entrainment of the retina of mammals is still a matter of debate, and recent studies have reported contradictory results in this respect. Here, we suggest that cryptochromes (CRY), in particular CRY 2, are involved in that light entrainment. CRY are highly conserved proteins that are a key component of the cellular circadian clock machinery. In plants and insects, they are responsible for the light entrainment of these biorhythms, mediated by the light response of their flavin cofactor (FAD). In mammals, however, no light-dependent role is currently assumed for CRY in light-exposed tissues, including the retina. It has been reported that FAD influences the function of mammalian CRY 2 and that human CRY 2 responds to light in Drosophila, suggesting that mammalian CRY 2 keeps the ability to respond to light. Here, we hypothesize that CRY 2 plays a role in the light entrainment of retinal biorhythms, at least in diurnal mammals. Indeed, published data shows that the light intensity dependence and the wavelength sensitivity commonly reported for that light entrainment fits the light sensitivity and absorption spectrum of light-responsive CRY. We propose experiments to test our hypothesis and to further explore the still-pending question of the function of CRY 2 in the mammalian retina.


Asunto(s)
Ritmo Circadiano/fisiología , Criptocromos/metabolismo , Proteínas de Drosophila/metabolismo , Células Fotorreceptoras/fisiología , Animales , Drosophila melanogaster/fisiología , Humanos , Luz , Retina/fisiología
10.
BMC Neurol ; 20(1): 36, 2020 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-31992235

RESUMEN

BACKGROUND: To investigate the relationships between blood pressure (BP) circadian rhythms and acute cerebral infarction (ACI), silent cerebral infarction (SCI) and the severity of leukoaraiosis in hypertensive patients. METHODS: A retrospective case-control study was performed among hypertensive patients with 24-h ambulatory blood pressure monitoring (ABPM) and cranial magnetic resonance imaging (MRI). RESULTS: A total of 1267 patients were enrolled. Lower nocturnal blood pressure (BP) decreases were observed in ACI patients than in controls (3.3% vs 8.2%, P<0.001). Reverse-dipper pattern (RD) and non-dipper pattern (ND) were found to be independent risk factors for ACI. In ACI patients, both RD and ND BP circadian rhythms were revealed to be independent risk factors for moderate-severe leukoaraiosis. In addition, in SCI patients, RD (OR = 1.7, 95% CI, 0.9-3.0; P = 0.047) or extreme-dipper pattern (ED) (OR = 2.9, 95% CI, 1.2-7.0; P = 0.015) were found to be independent risk factors for moderate-severe leukoaraiosis. Moreover, the greater the severity of leukoaraiosis was, the higher the ratio of abnormal BP circadian rhythms. CONCLUSION: RD and ND BP circadian rhythms might not only be relevant to the onset of ACI but also correlate with the severity of leukoaraiosis. Thus, when modulating BP with antihypertensive drugs, the BP circadian rhythms, and not merely the BP level, should warrant more attention.


Asunto(s)
Presión Sanguínea/fisiología , Infarto Cerebral/fisiopatología , Ritmo Circadiano/fisiología , Hipertensión/fisiopatología , Leucoaraiosis/fisiopatología , Anciano , Monitoreo Ambulatorio de la Presión Arterial , Estudios de Casos y Controles , Infarto Cerebral/etiología , Femenino , Humanos , Hipertensión/complicaciones , Leucoaraiosis/etiología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo
11.
PLoS One ; 15(1): e0227002, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31923256

RESUMEN

A lifestyle with erratic eating patterns and habits predisposes youngsters to obesity. Through a two-phase feasibility study among Indian students living in the Delhi area, we longitudinally examined the following: (1) the daily eating-fasting cycles of students (N = 34) in school and college using smartphones as they transition from high school (aged 13-15 years; nIX = 13) to higher secondary school (HSSS; 16-18 years; nXII = 9) to their first year (FY) of college (18-19 years; nFC = 12); and (2) daily activity-rest cycles and light-dark exposure of 31 higher secondary school students (HSSS) using actigraphy. In phase 1, students' food data were analyzed for temporal details of eating events and observable differences in diet composition, such as an energy-dense diet (fast food (FF)), as confounding factors of circadian health. Overall, the mean eating duration in high school, higher secondary and FY college students ranged from 14.1 to 16.2h. HSSS exhibited the shortest night fasting. Although FY college students exhibited the highest fast food percentage (FF%), a positive correlation between body mass index (BMI) and FF% was observed only among HSSS. Furthermore, the body weight of HSSS was significantly higher, indicating that FF, untimely eating and reduced night fasting were important obesity-associated factors in adolescents. Reduced night fasting duration was also related to shorter sleep in HSSS. Therefore, food data were supplemented with wrist actigraphy, i.e., activity-rest data, in HSSS. Actigraphy externally validated the increased obesogenic consequences of deregulated eating rhythms in HSSS. CamNtech motion watches were used to assess the relationship between disturbed activity cycles of HSSS and other circadian clock-related rhythms, such as sleep. Less than 50% of Indian HSSS slept 6 hours or more per night. Seven of 31 students remained awake throughout the night, during which they had more than 20% of their daily light exposure. Three nonparametric circadian rhythm analysis (NPCRA) variables revealed circadian disruption of activity in HSSS. The present study suggests that inappropriate timing and quality of food and sleep disturbances are important determinants of circadian disruptions in adolescents attending school.


Asunto(s)
Ciclos de Actividad/fisiología , Ritmo Circadiano/fisiología , Obesidad/etiología , Adolescente , Ingestión de Alimentos/fisiología , Ayuno/fisiología , Femenino , Humanos , India , Masculino , Obesidad/fisiopatología , Descanso/fisiología , Instituciones Académicas , Estudiantes , Adulto Joven
12.
Cell Prolif ; 53(1): e12727, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31747713

RESUMEN

OBJECTIVE: Chondrogenesis and endochondral ossification in mandibular condyle play crucial roles in maxillofacial morphogenesis and function. Circadian regulator brain and muscle arnt-like 1 (BMAL1) is proven to be essential for embryonic and postnatal development. The goal of this study was to define the functions of BMAL1 in the embryonic and postnatal growth of mandibular condylar cartilages (MCC). MATERIALS AND METHODS: Micro-CT, TUNEL staining and EdU assay were performed using BMAL1-deficient mice model, and in vitro experiments were performed using rat chondrocytes isolated from MCC. RNA sequencing in mandibular condyle tissues from Bmal1-/- mice and the age-matched wild-type mice was used for transcriptional profiling at different postnatal stages. RESULTS: The expression levels of BMAL1 decrease gradually in MCC. BMAL1 is proved to regulate sequential chondrocyte differentiation, and its deficiency can result in the impairment of endochondral ossification of MCC. RNA sequencing reveals hedgehog signalling pathway is the potential target of BMAL1. BMAL1 regulates hedgehog signalling and affects its downstream cascades through directly binding to the promoters of Ptch1 and Ihh, modulating targets of hedgehog signalling which is indispensable for endochondral ossification. Importantly, the short stature phenotypes caused by BMAL1 deficiency can be rescued by hedgehog signalling activator. CONCLUSIONS: Collectively, these results indicate that BMAL1 plays critical roles on chondrogenesis and endochondral ossification of MCC, giving a new insight on potential therapeutic strategies for facial dysmorphism.


Asunto(s)
Factores de Transcripción ARNTL/metabolismo , Cartílago/embriología , Diferenciación Celular/fisiología , Condrocitos/metabolismo , Ritmo Circadiano/fisiología , Cóndilo Mandibular/embriología , Transducción de Señal/fisiología , Animales , Cartílago/citología , Condrocitos/citología , Condrogénesis/fisiología , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Cóndilo Mandibular/citología , Ratones , Ratones Noqueados , Receptor Patched-1/genética , Receptor Patched-1/metabolismo
13.
Environ Pollut ; 256: 113314, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31761596

RESUMEN

Urbanisation is increasing globally at a rapid pace. Consequently, wild species face novel environmental stressors associated with urban sprawl, such as artificial light at night and noise. These stressors have pervasive effects on the behaviour and physiology of many species. Most studies have singled out the impact of just one of these stressors, while in the real world they are likely to co-occur both temporally and spatially, and we thus lack a clear understanding of the combined effect of anthropogenic stressors on wild species. Here, we experimentally exposed captive male great tits (Parus major) to artificial light at night and 24 h noise in a fully factorial experiment. We then measured the effect of both these stressors on their own and their combination on the amount and timing of activity patterns. We found that both light and noise affected activity patterns when presented alone, but in opposite ways: light increased activity, particularly at night, while noise reduced it, particularly during the day. When the two stressors were combined, we found a synergistic effect on the total activity and the nighttime activity, but an antagonistic effect on daytime activity. The significant interaction between noise and light treatment also differed among forest and city birds. Indeed, we detected a significant interactive effect on light and noise on daytime, nighttime, dusktime and offset of activity of urban birds, but not of forest birds. These results suggest that both artificial light at night and anthropogenic noise can drive changes in activity patterns, but that the specific impacts depend on the habitat of origin. Furthermore, our results demonstrate that co-occurring exposure to noise and light can lead to a stronger impact at night than predicted from the additive effects and thus that multisensory pollution may be a considerable threat for wildlife.


Asunto(s)
Conducta Animal/fisiología , Luz/efectos adversos , Ruido/efectos adversos , Pájaros Cantores/fisiología , Animales , Animales Salvajes , Ritmo Circadiano/fisiología , Ciudades , Ecosistema , Masculino , Países Bajos , Fotoperiodo , Estaciones del Año , Urbanización
14.
Behav Sleep Med ; 18(1): 23-34, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31030562

RESUMEN

Objective/Background: Sleep and circadian disorders are prevalent worldwide and frequently comorbid with physical and mental illnesses. Thus, recruiting and retaining samples for sleep and circadian research are high priorities. The aims of this paper are to highlight barriers to recruitment and retention for participants with sleep or circadian dysfunction, and to share strategies used across two randomized controlled trials (RCTs) testing the efficacy of the Transdiagnostic Intervention for Sleep and Circadian Dysfunction (TranS-C) to address these challenges. Participants: The first RCT recruited 176 adolescents with an evening circadian chronotype, who were at risk in at least one of five health domains: behavioral, cognitive, emotional, physical, and social. The second RCT recruited 121 low-income, racial or ethnic minority adults diagnosed with severe mental illness (SMI) and comorbid sleep or circadian dysfunction. Methods: The current study examined participant, environment, and research factors that impacted recruitment and retention of participants with sleep or circadian dysfunction, and identified strategies to enhance recruitment and retention. Results: Strategies used to recruit participants included community-based recruiting, reducing stigma, and alleviating burdensome sleep data collection. Strategies used to retain participants in our studies included flexible scheduling, mitigating participant barriers, building rapport with participants through empathic and positive interactions, creative problem solving, consulting participant networks, and utilizing incentives and other positive engagement tools. Conclusion: Both at-risk adolescents and low-income, minority adults with comorbid SMI and sleep or circadian dysfunction experience significant barriers to research participation. Recruitment and retention strategies were creatively tailored to meet the unique barriers of these diverse populations.


Asunto(s)
Ritmo Circadiano/fisiología , Sueño/fisiología , Adolescente , Niño , Femenino , Humanos , Masculino
15.
Gen Comp Endocrinol ; 285: 113296, 2020 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-31589833

RESUMEN

The 24 h geophysical light-dark cycle is the main organizer of daily rhythms, scheduling physiology and behavior. This cycle attenuates greatly during the continuous light of summer at polar latitudes, resulting in species-specific and even individual-specific patterns of behavioral rhythmicity, but the physiological mechanisms underlying this variation are poorly understood. To address this knowledge gap and to better understand the roles of the hormones melatonin and corticosterone in rhythmic behavior during this 'polar day', we exploited the behavior of thick-billed murres (Uria lomvia), a charadriiform seabird with sexually opposite ('antiphase') activity-rhythms that have a duration of 24 h. Melatonin concentration in the plasma of inactive males was unexpectedly high around midday and subsequently fell during a sudden decrease in light intensity as the colony became shaded. Corticosterone concentration in plasma did not vary with time of day or activity in either sex. While the reasons for these unusual patterns remain unclear, we propose that a flexible melatonin response and little diel variation of corticosterone may be adaptive in thick-billed murres, and perhaps other polar birds and mammals, by stabilizing glucocorticoids' role of modulating energy storage and mobilization across the diel cycle and facilitating the appropriate reaction to unexpected stimuli experienced across the diel cycle while attending the colony.


Asunto(s)
Charadriiformes/sangre , Charadriiformes/fisiología , Ritmo Circadiano/fisiología , Corticosterona/sangre , Melatonina/sangre , Animales , Femenino , Luz , Masculino , Estaciones del Año
16.
Clin Exp Hypertens ; 42(1): 86-92, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-30895812

RESUMEN

Introduction: There is not enough data on the effects of primary hyperparathyroidism (pHPT) on morning blood pressure surge (MBPS) in the literature. We aimed to determine whether there was any change in MBPS value in patients with hypertensive pHPT and to determine the parameters related to MBPS.Method: 80 patients with newly diagnosed pHPT with hypertension (HT) and 80 controls with newly diagnosed hypertension were included. Routine laboratory examinations and ambulatory blood pressure monitoring (ABPM) were performed in all patients.Results: In patients with pHPT, blood urea nitrogen (BUN), triglyceride, hs-CRP, uric acid, serum calcium (Ca), parathormone (PTH), daytime SBP and MBPS levels are higher than others (p < 0.05). Body mass index (BMI) and Ca level were independently associated with MBPS. In patients with MBPS ≥ 25 mmHg, BMI, BUN, creatinine, uric acid, Ca and PTH levels were found to be higher than others. BMI values and Ca levels determine the patients with MBPS ≥ 25 mmHg (p < 0.05) independently. According to this analysis, increase in BMI (for each 1 unit) and Ca level (for each 0.1 mg/dL) was found to increase the probability of MBPS ≥ 25 mmHg by 17.8% and 7.7%, respectively. When the cut-off value for Ca was taken as 10 mg/dL, the patients with MBPS ≥ 25 mmHg were determined with 73.5% sensitivity and 73.1% specificity.Conclusion: MBPS significantly increases in patients with newly diagnosed hypertensive pHPT. This increase in MBPS is closely associated with increased Ca levels. In patients with pHPT, lowering the Ca level below 10 mg/dL may have clinical implications.


Asunto(s)
Presión Sanguínea , Calcio/sangre , Hiperparatiroidismo Primario/fisiopatología , Hipertensión/fisiopatología , Adulto , Anciano , Monitoreo Ambulatorio de la Presión Arterial , Nitrógeno de la Urea Sanguínea , Índice de Masa Corporal , Ritmo Circadiano/fisiología , Creatinina/sangre , Femenino , Humanos , Hiperparatiroidismo Primario/complicaciones , Hipertensión/complicaciones , Masculino , Persona de Mediana Edad , Hormona Paratiroidea/sangre , Sensibilidad y Especificidad , Factores de Tiempo , Ácido Úrico/sangre
17.
Int J Cancer ; 146(3): 664-670, 2020 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-30895617

RESUMEN

Breast cancer is the most common cancer and the second-leading cause of cancer-related death among women. Inconsistent findings for the relationship between melatonin levels, sleep duration and breast cancer have been reported. We investigated the association of sleep duration at cohort entry and its interaction with body mass index (BMI) with risk of developing breast cancer in the large population-based Multiethnic Cohort study. Among the 74,481 at-risk participants, 5,790 breast cancer cases were identified during the study period. Although we detected no significant association between sleep duration and breast cancer incidence, higher risk estimates for short (HR = 1.03; 95% CI: 0.97-1.09) and long sleep (HR = 1.05; 95% CI: 0.95-1.15) compared to normal sleep (7-8 hr) were found. The patterns for models stratified by age, BMI, ethnicity and hormone receptor status were similar but did not indicate significant interaction effects. When examining the combined sleep duration and BMI interaction effect, in comparison to the normal BMI-normal sleep group, risk estimates for underweight, overweight and obesity were similar across categories of sleep duration (≤6, 7-8, and ≥9 hr). The underweight-normal sleep group had lower breast cancer incidence (HR = 0.66, 95% CI: 0.50-0.86), whereas the overweight-short sleep, overweight-normal sleep group and all obese women experienced elevated breast cancer incidence. The respective HRs for short, normal and long sleep among obese women were 1.35 (95% CI: 1.20-1.53), 1.27 (95% CI: 1.15-1.42) and 1.46 (95% CI: 1.21-1.76). Future perspectives need to examine the possibility that sleep quality, variations in circadian rhythm and melatonin are involved in breast cancer etiology.


Asunto(s)
Neoplasias de la Mama/epidemiología , Sobrepeso/epidemiología , Sueño/fisiología , Delgadez/epidemiología , Anciano , Índice de Masa Corporal , Neoplasias de la Mama/etiología , California/epidemiología , Ritmo Circadiano/fisiología , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Persona de Mediana Edad , Sobrepeso/complicaciones , Medición de Riesgo , Factores de Riesgo , Delgadez/complicaciones , Factores de Tiempo
18.
Proc Natl Acad Sci U S A ; 117(1): 668-676, 2020 01 07.
Artículo en Inglés | MEDLINE | ID: mdl-31848247

RESUMEN

The glymphatic system functions in the removal of potentially harmful metabolites and proteins from the brain. Dynamic, contrast-enhanced MRI was used in fully awake rats to follow the redistribution of intraventricular contrast agent entrained to the light-dark cycle and its hypothetical relationship to the sleep-waking cycle, blood flow, and brain temperature in specific brain areas. Brain areas involved in circadian timing and sleep-wake rhythms showed the lowest redistribution of contrast agent during the light phase or time of inactivity and sleep in rats. Global brain redistribution of contrast agent was heterogeneous. The redistribution was highest along the dorsal cerebrum and lowest in the midbrain/pons and along the ventral surface of the brain. This heterogeneous redistribution of contrast agent paralleled the gradients and regional variations in brain temperatures reported in the literature for awake animals. Three-dimensional quantitative ultrashort time-to-echo contrast-enhanced imaging was used to reconstruct small, medium, and large arteries and veins in the rat brain and revealed areas of lowest redistribution overlapped with this macrovasculature. This study raises new questions and theoretical considerations of the impact of the light-dark cycle, brain temperature, and blood flow on the function of the glymphatic system.


Asunto(s)
Ritmo Circadiano/fisiología , Sistema Glinfático/diagnóstico por imagen , Fotoperiodo , Vigilia/fisiología , Animales , Temperatura Corporal/fisiología , Circulación Cerebrovascular/fisiología , Medios de Contraste/administración & dosificación , Sistema Glinfático/fisiología , Imagenología Tridimensional , Imagen por Resonancia Magnética , Masculino , Modelos Animales , Ratas , Sueño/fisiología
19.
Proc Natl Acad Sci U S A ; 117(2): 993-999, 2020 01 14.
Artículo en Inglés | MEDLINE | ID: mdl-31879354

RESUMEN

An intimate link exists between circadian clocks and metabolism with nearly every metabolic pathway in the mammalian liver under circadian control. Circadian regulation of metabolism is largely driven by rhythmic transcriptional activation of clock-controlled genes. Among these output genes, Nocturnin (Noct) has one of the highest amplitude rhythms at the mRNA level. The Noct gene encodes a protein (NOC) that is highly conserved with the endonuclease/exonuclease/phosphatase (EEP) domain-containing CCR4 family of deadenylases, but highly purified NOC possesses little or no ribonuclease activity. Here, we show that NOC utilizes the dinucleotide NADP(H) as a substrate, removing the 2' phosphate to generate NAD(H), and is a direct regulator of oxidative stress response through its NADPH 2' phosphatase activity. Furthermore, we describe two isoforms of NOC in the mouse liver. The cytoplasmic form of NOC is constitutively expressed and associates externally with membranes of other organelles, including the endoplasmic reticulum, via N-terminal glycine myristoylation. In contrast, the mitochondrial form of NOC possesses high-amplitude circadian rhythmicity with peak expression level during the early dark phase. These findings suggest that NOC regulates local intracellular concentrations of NADP(H) in a manner that changes over the course of the day.


Asunto(s)
Ritmo Circadiano/fisiología , Hígado/metabolismo , Proteínas Nucleares/metabolismo , Nucleotidasas/metabolismo , Estrés Oxidativo/fisiología , Factores de Transcripción/metabolismo , Animales , Relojes Circadianos/genética , Relojes Circadianos/fisiología , Ritmo Circadiano/genética , Regulación de la Expresión Génica , Células HEK293 , Humanos , Ratones , Ratones Noqueados , Mitocondrias/metabolismo , Proteínas Nucleares/genética , ARN Mensajero/metabolismo , Factores de Transcripción/genética , Transcriptoma
20.
Accid Anal Prev ; 136: 105402, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31862644

RESUMEN

Circadian rhythms are changes in life activities over a cycle of approximately 24 hours. Studies on chronotypes have found that there are significant differences in physiology, personality, cognitive ability and driving behavior between morning-type and evening-type people. The purpose of this study is to explore the relationship between visual-spatial working memory and driving behavior between morning-type and evening-type drivers in China. A total of 42 Chinese drivers were selected to participate in this study according to their score on the Morningness-Eveningness Questionnaire, including 22 morning-type drivers and 20 evening-type drivers. During the experiment, the participants completed one cognitive task (visual-spatial working memory), two simulated driving tasks (car-following task and pedestrian-crossing task), and the Dula Dangerous Driving Index (DDDI). The results showed that evening-type drivers self-reported more dangerous driving behaviors but had better lateral control on the simulated driving task than morning-type drivers. In addition, evening-type drivers had greater accuracy when performing the visual-spatial working memory task. Moreover, the accuracy on the visual-spatial working memory task positively predicted the percentage of time over the speed limit by 10 mph (POS10) and negatively correlated with the reaction time measure (time to meet pedestrians) in the pedestrian-crossing task. The relationships among chronotype, cognitive ability and driving behavior are also discussed. Understanding the underlying mechanisms could help explain why evening-type drivers perform dangerous driving behaviors more often.


Asunto(s)
Conducción de Automóvil/psicología , Ritmo Circadiano/fisiología , Memoria a Corto Plazo/fisiología , Adulto , China , Conducta Peligrosa , Femenino , Humanos , Masculino , Tiempo de Reacción/fisiología , Autoinforme , Adulto Joven
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