A5075158622- Circadian rhythm and melatonin
- Sleep and related disorders
- Sleep and Wakefulness Research
- Impact of Light on Environment and Health
- Obstructive Sleep Apnea Research
- Spaceflight effects on biology
- Sleep and Work-Related Fatigue
- Olfactory and Sensory Function Studies
- Photoreceptor and optogenetics research
- Dietary Effects on Health
- Melanoma and MAPK Pathways
- Cutaneous Melanoma Detection and Management
- Metabolomics and Mass Spectrometry Studies
- Non-Invasive Vital Sign Monitoring
- Computational Drug Discovery Methods
- EEG and Brain-Computer Interfaces
- Dementia and Cognitive Impairment Research
- Heart Rate Variability and Autonomic Control
- Electromagnetic Fields and Biological Effects
- Health, Environment, Cognitive Aging
- Context-Aware Activity Recognition Systems
- High Altitude and Hypoxia
- Adipose Tissue and Metabolism
- Psychological and Temporal Perspectives Research
- Genetics, Aging, and Longevity in Model Organisms
University of Surrey
2016-2025
Imperial College London
2021-2024
UK Dementia Research Institute
2021-2024
University of Manchester
2010-2023
University of St Andrews
2023
Sleep Research Society
2023
Rush University Medical Center
2005-2007
Rhythm (United states)
2005
To provide guidelines for collecting and analyzing urinary, salivary, plasma melatonin, thereby assisting clinicians researchers in determining which method of measuring melatonin is most appropriate their particular needs facilitating the comparison data between laboratories.A modified RAND process was utilized to derive recommendations methods humans.Consensus-based are presented studies that conducted natural living environment, clinical setting, in-patient research facilities under...
Significance Sleep restriction and circadian clock disruption are associated with metabolic disorders including obesity diabetes; this association can be studied by using the powerful tool of metabolomics. By liquid chromatography/MS metabolomics, we have characterized plasma metabolites that were significantly affected acute sleep deprivation (mainly lipids acylcarnitines), all increasing during deprivation. Observed increased levels serotonin, tryptophan, taurine may explain antidepressive...
SummaryPhotoreceptive, melanopsin-expressing retinal ganglion cells (mRGCs) encode ambient light (irradiance) for the circadian clock, pupillomotor system, and other influential behavioral/physiological responses. mRGCs are activated both by their intrinsic phototransduction cascade rods cones. However, individual contribution of each photoreceptor class to irradiance responses remains unclear. We address this deficit using mice expressing human red cone opsin, in which rod-, cone-,...
Photoreception in the mammalian retina is not restricted to rods and cones but extends a small number of intrinsically photosensitive retinal ganglion cells expressing photopigment melanopsin. These mRGCs are especially important contributors circadian entrainment, pupil light reflex, other so-called nonimage-forming (NIF) responses. The spectral sensitivity melanopsin phototransduction has been addressed several species by comparing responses range monochromatic stimuli. resultant action...
Phase response curves (PRCs) to melatonin exist, but none compare different doses of using the same protocol.The aim was generate a PRC 0.5 mg oral and it our previously published 3.0 generated study included two 5-d sessions in laboratory, each preceded by 7-9 d fixed sleep times. Each session started ended with phase assessment measure dim light onset (DLMO). In between were 3 an ultradian (<150 lux)/dark cycle (light:dark, 2.5:1.5).Healthy adults (16 men, 18 women) ages 42 yr participated...
Context: Both light and melatonin can be used to phase shift the human circadian clock, but phase-advancing effect of combination has not been extensively investigated.
Exogenous melatonin is increasingly used for its phase shifting and soporific effects. We generated a three pulse response curve (PRC) to exogenous (3 mg) by administering it free‐running subjects. Young healthy subjects ( n = 27) participated in two 5 day laboratory sessions, each preceded at least week of habitual, but fixed sleep. Each session started ended with assessment measure the circadian rhythm endogenous dim light using 30 min saliva samples. In between were days an ultradian...
Although daily rhythms regulate multiple aspects of human physiology, rhythmic control the metabolome remains poorly understood. The primary objective this proof-of-concept study was identification metabolites in plasma that exhibit significant 24-h variation. This assessed via an untargeted metabolomic approach using liquid chromatography–mass spectrometry (LC-MS). Eight lean, healthy, and unmedicated men, mean age 53.6 (SD ± 6.0) yrs, maintained a fixed sleep/wake schedule dietary regime...
Reduced sensitivity to short-wavelength (blue) light with age has been shown for light-induced melatonin suppression. The current research aimed determine if a similar age-related reduction occurs in subjective alertness, mood, and circadian phase-advancing responses. Young (n = 11, 23.0 +/- 2.9 years) older 15, 65.8 5.0 healthy males participated laboratory sessions that included 2-h intermittent monochromatic exposure, individually timed begin 8.5 h after their dim onset (DLMO) determined...
Abstract Understanding how metabolite levels change over the 24 hour day is of crucial importance for clinical and epidemiological studies. Additionally, association between sleep deprivation metabolic disorders such as diabetes obesity requires investigation into links metabolism. Here, we characterise time-of-day variation effects on urinary profiles. Healthy male participants (n = 15) completed an in-laboratory study comprising one h sleep/wake cycle prior to continual wakefulness under...
The sleep/wake cycle is accompanied by changes in circulating numbers of immune cells. goal this study was to provide an in-depth characterization diurnal rhythms different blood cell populations and investigate the effect acute sleep deprivation on system, as indicator body's stress response.Observational within-subject design.Home environment Clinical Research Centre.15 healthy male participants aged 23.7 ± 5.4 (standard deviation) yr.Total deprivation.Diurnal several were assessed under a...
The increased prevalence of circadian disruptions due to abnormal coupling between internal and external time makes the detection phase in humans by ambulatory recordings a compelling need. Here, we propose an accurate practical procedure estimate with least possible burden for subject, that is, without restraints constant routine protocol or laboratory techniques such as melatonin quantification, both which are standard procedures. In this validation study, subjects (N = 13) wore monitoring...
ABSTRACT Conflicting evidence exists as to whether there are differences between males and females in circadian timing. The aim of the current study was assess sex present regulation melatonin cortisol plasma urine matrices during a constant routine protocol. Thirty-two healthy individuals (16 taking oral contraceptive pill (OCP)), aged 23.8 ± 3.7 (mean SD) years, participated. Blood (hourly) (4-hourly) samples were collected for measurement cortisol, urinary 6-sulfatoxymelatonin (aMT6s)...
Quantification of sleep is important for the diagnosis disorders and research. However, only widely accepted method to obtain staging by visual analysis polysomnography (PSG), which expensive time consuming. Here, we investigate automated scoring based on a low-cost, mobile electroencephalogram (EEG) platform consisting lightweight EEG amplifier combined with flex-printed cEEGrid electrodes placed around ear, can be implemented as fully self-applicable system. signals have different...
Abstract Studying circadian rhythms in most human tissues is hampered by difficulty collecting serial samples. Here we reveal the transcriptome and metabolic pathways of white adipose tissue. Subcutaneous tissue was taken from seven healthy males under highly controlled ‘constant routine’ conditions. Five biopsies per participant were at six-hourly intervals for microarray analysis silico integrative modelling. We identified 837 transcripts exhibiting expression profiles (2% 41619 transcript...
BackgroundThere is no consensus on reporting light characteristics in studies investigating non-visual responses to light. This project aimed develop a checklist for laboratory-based investigations the impact of physiology.MethodsA four-step modified Delphi process (three questionnaire-based feedback rounds and one face-to-face group discussion) involving international experts was conducted reach items be included checklist. Following process, resulting tested pilot phase with independent...
The relative contribution of rods, cones, and melanopsin to non‐image‐forming (NIF) responses under light conditions differing in irradiance, duration, spectral composition remains be determined humans. NIF a polychromatic source may very different that predicted from the published human action spectra data, which have utilized narrow band monochromatic demonstrated short wavelength sensitivity. To test hypothesis only is driving humans, blue (λmax 479 nm) was matched with white for total...
Background Diurnal behavior in humans is governed by the period length of a circadian clock suprachiasmatic nuclei brain hypothalamus. Nevertheless, cell-intrinsic mechanism this present most cells body. We have shown previously that for individuals extreme chronotype ("larks" and "owls"), properties measured human fibroblasts correlated with diurnal behavior. Methodology/Principal Findings In study, we primary taken from normal and, first time, compared it directly physiological vivo same...
This study investigated the impact of sleep deprivation on human circadian system. Plasma melatonin and cortisol levels leukocyte expression 12 genes were examined over 48 h (sleep vs. no-sleep nights) in young males (mean ± SD: 23 5 yrs). During one night total deprivation, BMAL1 was suppressed, heat shock gene HSPA1B induced, amplitude rhythm increased, whereas other high-amplitude clock rhythms (e.g., PER1-3, REV-ERBα) remained unaffected. These data suggest that core mechanism peripheral...
Objective In an effort to enhance the efficiency, brightness and contrast of light-emitting (LE) devices during day, displays often generate substantial short-wavelength (blue-enriched) light emissions that can adversely affect sleep. We set out verify extent such emissions, produced by a tablet (iPad Air), e-reader (Kindle Paperwhite 1st generation) smartphone (iPhone 5s) determine impact strategies designed reduce these emissions. Setting University Surrey dedicated chronobiology facility....
Electroencephalography (EEG) recordings represent a vital component of the assessment sleep physiology, but methodology presently used is costly, intrusive to participants, and laborious in application. There recognized need develop more easily applicable yet reliable EEG systems that allow unobtrusive long-term recording sleep-wake ideally away from laboratory setting. cEEGrid recently developed flex-printed around-the-ear electrode array, which holds great potential for monitoring...
Disruption to sleep and circadian rhythms can impact on metabolism. The study aimed investigate the effect of acute deprivation plasma melatonin, cortisol metabolites, increase understanding metabolic pathways involved in sleep/wake regulation processes. Twelve healthy young female participants remained controlled laboratory conditions for ~92 hr with respect posture, meals environmental light (18:00-23:00 07:00-09:00 <8 lux; 23:00-07:00 0 lux (sleep opportunity) or (continuous wakefulness);...