The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs and stimuli, hormone secretion, sleeping, and feeding.
Dyssomnias associated with disruption of the normal 24 hour sleep wake cycle secondary to travel (e.g., JET LAG SYNDROME), shift work, or other causes.
An ovoid densely packed collection of small cells of the anterior hypothalamus lying close to the midline in a shallow impression of the OPTIC CHIASM.
Circadian rhythm signaling proteins that influence circadian clock by interacting with other circadian regulatory proteins and transporting them into the CELL NUCLEUS.
A broad category of proteins that regulate the CIRCADIAN RHYTHM of an organism. Included here are proteins that transmit intracellular and intercellular signals in a chronological manner along with proteins that sense light and time-dependent changes in the environment such as the PHOTOPERIOD.
Basic helix-loop-helix (bHLH) domain-containing proteins that contain intrinsic HISTONE ACETYLTRANSFERASE activity and play important roles in CIRCADIAN RHYTHM regulation. Clock proteins combine with Arntl proteins to form heterodimeric transcription factors that are specific for E-BOX ELEMENTS and stimulate the transcription of several E-box genes that are involved in cyclical regulation. This transcriptional activation also sets into motion a time-dependent feedback loop which in turn down-regulates the expression of clock proteins.
The physiological mechanisms that govern the rhythmic occurrence of certain biochemical, physiological, and behavioral phenomena.
Biological mechanism that controls CIRCADIAN RHYTHM. Circadian clocks exist in the simplest form in cyanobacteria and as more complex systems in fungi, plants, and animals. In humans the system includes photoresponsive RETINAL GANGLION CELLS and the SUPRACHIASMATIC NUCLEUS that acts as the central oscillator.
The time period of daily exposure that an organism receives from daylight or artificial light. It is believed that photoperiodic responses may affect the control of energy balance and thermoregulation.
Basic helix-loop-helix (bHLH) domain-containing proteins that play important roles in CIRCADIAN RHYTHM regulation. They combine with CLOCK PROTEINS to form heterodimeric transcription factors that are specific for E-BOX ELEMENTS and stimulate the transcription of several E-box genes that are involved in cyclical regulation.
Disruptions of the rhythmic cycle of bodily functions or activities.
A biogenic amine that is found in animals and plants. In mammals, melatonin is produced by the PINEAL GLAND. Its secretion increases in darkness and decreases during exposure to light. Melatonin is implicated in the regulation of SLEEP, mood, and REPRODUCTION. Melatonin is also an effective antioxidant.
Bouts of physical irritability or movement alternating with periods of quiescence. It includes biochemical activity and hormonal activity which may be cellular. These cycles are shorter than 24 hours and include sleep-wakefulness cycles and the periodic activation of the digestive system.
A chronobiologic disorder resulting from rapid travel across a number of time zones, characterized by insomnia or hypersomnolence, fatigue, behavioral symptoms, headaches, and gastrointestinal disturbances. (From Cooper, Sleep, 1994, pp593-8)
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
The absence of light.
Flavoproteins that function as circadian rhythm signaling proteins in ANIMALS and as blue-light photoreceptors in PLANTS. They are structurally-related to DNA PHOTOLYASES and it is believed that both classes of proteins may have originated from an earlier protein that played a role in protecting primitive organisms from the cyclical exposure to UV LIGHT.
The measure of the level of heat of a human or animal.
A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility.
The tendency of a phenomenon to recur at regular intervals; in biological systems, the recurrence of certain activities (including hormonal, cellular, neural) may be annual, seasonal, monthly, daily, or more frequently (ultradian).
The physical activity of a human or an animal as a behavioral phenomenon.
A DNA-binding orphan nuclear receptor that negatively regulates expression of ARNTL TRANSCRIPTION FACTORS and plays a role as a regulatory component of the circadian clock system. The Nr1d1 nuclear receptor expression is cyclically-regulated by a feedback loop involving its positive regulation by CLOCK PROTEIN; BMAL1 PROTEIN heterodimers and its negative regulation by CRYPTOCHROME and PERIOD PROTEINS.
A light-sensitive neuroendocrine organ attached to the roof of the THIRD VENTRICLE of the brain. The pineal gland secretes MELATONIN, other BIOGENIC AMINES and NEUROPEPTIDES.
Treatment of disease by exposure to light, especially by variously concentrated light rays or specific wavelengths.
A casein kinase I isoenzyme with specificity for proteins involved the regulation of the CIRCADIAN RHYTHM.
The adaptation of therapeutic approaches such as pharmacological (DRUG CHRONOTHERAPY), surgical, radiological, or physical to the known variations in biological RHYTHMICITY, such as CIRCADIAN RHYTHMS. The treatment is aimed at supporting normal rhythms, or modifying the timing of therapy to achieve maximal efficacy and minimal adverse effect.
The illumination of an environment and the arrangement of lights to achieve an effect or optimal visibility. Its application is in domestic or in public settings and in medical and non-medical environments.
Biological systems as affected by time. Aging, biological rhythms, and cyclic phenomena are included. Statistical, computer-aided mathematical procedures are used to describe, in mathematical terminology, various biological functions over time.
A state in which there is an enhanced potential for sensitivity and an efficient responsiveness to external stimuli.
The main glucocorticoid secreted by the ADRENAL CORTEX. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions.
An acetyltransferase with specificity towards the amine group of aromatic alkylamines (arylalkylamines) such as SEROTONIN. This enzyme is also referred to as serotonin acetylase despite the fact that serotonin acetylation can also occur through the action of broad specificity acetyltransferases such as ARYLAMINE N-ACETYLTRANSFERASE.
Elements of limited time intervals, contributing to particular results or situations.
The adaptation of drug administration to the known variations in biological RHYTHMICITY, such as CIRCADIAN RHYTHMS. The treatment is aimed at supporting normal rhythms, or modifying the timing of therapy to achieve maximal efficacy and minimal adverse effect.
Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.
The observable response an animal makes to any situation.
A family of G-protein-coupled receptors that are specific for and mediate the effects of MELATONIN. Activation of melatonin receptors has been associated with decreased intracellular CYCLIC AMP and increased hydrolysis of PHOSPHOINOSITIDES.
A syndrome characterized by depressions that recur annually at the same time each year, usually during the winter months. Other symptoms include anxiety, irritability, decreased energy, increased appetite (carbohydrate cravings), increased duration of sleep, and weight gain. SAD (seasonal affective disorder) can be treated by daily exposure to bright artificial lights (PHOTOTHERAPY), during the season of recurrence.
A genus of the family Muridae having three species. The present domesticated strains were developed from individuals brought from Syria. They are widely used in biomedical research.
Photosensitive proteins expressed in the ROD PHOTORECEPTOR CELLS. They are the protein components of rod photoreceptor pigments such as RHODOPSIN.
Physiological or psychological effects of periods of work which may be fixed or flexible such as flexitime, work shifts, and rotating shifts.
A DNA-binding orphan nuclear receptor that positively regulates expression of ARNTL TRANSCRIPTION FACTORS and is a regulatory component of the circadian clock system. The protein also has a role in neuron cell survival and differentiation in that loss of function mutations of its gene result in the mouse phenotype referred to as the STAGGERER MOUSE.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.
The measurement of frequency or oscillation changes.
The number of times the HEART VENTRICLES contract per unit of time, usually per minute.
An adrenocortical steroid that has modest but significant activities as a mineralocorticoid and a glucocorticoid. (From Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed, p1437)
The conversion of absorbed light energy into molecular signals.
Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.
An aggregation of cells in the middle hypothalamus dorsal to the ventromedial nucleus and bordering the THIRD VENTRICLE.
The state of being deprived of sleep under experimental conditions, due to life events, or from a wide variety of pathophysiologic causes such as medication effect, chronic illness, psychiatric illness, or sleep disorder.
Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.
A form-genus of spherical to rod-shaped CYANOBACTERIA in the order Chroococcales. They contain THYLAKOIDS and are found in a wide range of habitats.
Specialized cells in the invertebrates that detect and transduce light. They are predominantly rhabdomeric with an array of photosensitive microvilli. Illumination depolarizes invertebrate photoreceptors by stimulating Na+ influx across the plasma membrane.
A mechanism of communication with a physiological system for homeostasis, adaptation, etc. Physiological feedback is mediated through extensive feedback mechanisms that use physiological cues as feedback loop signals to control other systems.
Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.
A family of DNA-binding transcription factors that contain a basic HELIX-LOOP-HELIX MOTIF.
Processes and properties of the EYE as a whole or of any of its parts.
A broad category of sleep disorders characterized by either hypersomnolence or insomnia. The three major subcategories include intrinsic (i.e., arising from within the body) (SLEEP DISORDERS, INTRINSIC), extrinsic (secondary to environmental conditions or various pathologic conditions), and disturbances of circadian rhythm. (From Thorpy, Sleep Disorders Medicine, 1994, p187)
Brain waves characterized by a relatively high voltage or amplitude and a frequency of 8-13 Hz. They constitute the majority of waves recorded by EEG registering the activity of the parietal and occipital lobes when the individual is awake, but relaxed with the eyes closed.
Abnormal cardiac rhythm that is characterized by rapid, uncoordinated firing of electrical impulses in the upper chambers of the heart (HEART ATRIA). In such case, blood cannot be effectively pumped into the lower chambers of the heart (HEART VENTRICLES). It is caused by abnormal impulse generation.
Transmission of the readings of instruments to a remote location by means of wires, radio waves, or other means. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
The clear, viscous fluid secreted by the SALIVARY GLANDS and mucous glands of the mouth. It contains MUCINS, water, organic salts, and ptylin.
Removal of an autonomic or sensory ganglion by any means.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Periods of sleep manifested by changes in EEG activity and certain behavioral correlates; includes Stage 1: sleep onset, drowsy sleep; Stage 2: light sleep; Stages 3 and 4: delta sleep, light sleep, deep sleep, telencephalic sleep.
Enzymes that oxidize certain LUMINESCENT AGENTS to emit light (PHYSICAL LUMINESCENCE). The luciferases from different organisms have evolved differently so have different structures and substrates.
A casein kinase I isoenzyme that plays a regulatory role in a variety of cellular functions including vesicular transport, CHROMOSOME SEGREGATION; CYTOKINESIS, developmental processes, and the CIRCADIAN RHYTHM.
Peptides released by NEURONS as intercellular messengers. Many neuropeptides are also hormones released by non-neuronal cells.
The consumption of edible substances.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
A species of ascomycetous fungi of the family Sordariaceae, order SORDARIALES, much used in biochemical, genetic, and physiologic studies.
Specialized cells that detect and transduce light. They are classified into two types based on their light reception structure, the ciliary photoreceptors and the rhabdomeric photoreceptors with MICROVILLI. Ciliary photoreceptor cells use OPSINS that activate a PHOSPHODIESTERASE phosphodiesterase cascade. Rhabdomeric photoreceptor cells use opsins that activate a PHOSPHOLIPASE C cascade.
DNA locations with the consensus sequence CANNTG. ENHANCER ELEMENTS may contain multiple copies of this element. E-boxes play a regulatory role in the control of transcription. They bind with basic helix-loop-helix (bHLH) type TRANSCRIPTION FACTORS. Binding specificity is determined by the specific bHLH heterodimer or homodimer combination and by the specific nucleotides at the 3rd and 4th position of the E-box sequence.
Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.
A genus of hamsters characterized by small size, very short tail, and short, broad feet with hairy soles.
A highly basic, 28 amino acid neuropeptide released from intestinal mucosa. It has a wide range of biological actions affecting the cardiovascular, gastrointestinal, and respiratory systems and is neuroprotective. It binds special receptors (RECEPTORS, VASOACTIVE INTESTINAL PEPTIDE).
The processes of heating and cooling that an organism uses to control its temperature.
Techniques used for determining the values of photometric parameters of light resulting from LUMINESCENCE.
A casein kinase that was originally described as a monomeric enzyme with a molecular weight of 30-40 kDa. Several ISOENZYMES of casein kinase I have been found which are encoded by separate genes. Many of the casein kinase I isoenzymes have been shown to play distinctive roles in intracellular SIGNAL TRANSDUCTION.
Conditions characterized by disturbances of usual sleep patterns or behaviors. Sleep disorders may be divided into three major categories: DYSSOMNIAS (i.e. disorders characterized by insomnia or hypersomnia), PARASOMNIAS (abnormal sleep behaviors), and sleep disorders secondary to medical or psychiatric disorders. (From Thorpy, Sleep Disorders Medicine, 1994, p187)
A stage of sleep characterized by rapid movements of the eye and low voltage fast pattern EEG. It is usually associated with dreaming.
A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.
Any type of variation in the appearance of energy output of the sun. (NASA Thesaurus, 1994)
Proteins that control the CELL DIVISION CYCLE. This family of proteins includes a wide variety of classes, including CYCLIN-DEPENDENT KINASES, mitogen-activated kinases, CYCLINS, and PHOSPHOPROTEIN PHOSPHATASES as well as their putative substrates such as chromatin-associated proteins, CYTOSKELETAL PROTEINS, and TRANSCRIPTION FACTORS.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A phylum of oxygenic photosynthetic bacteria comprised of unicellular to multicellular bacteria possessing CHLOROPHYLL a and carrying out oxygenic PHOTOSYNTHESIS. Cyanobacteria are the only known organisms capable of fixing both CARBON DIOXIDE (in the presence of light) and NITROGEN. Cell morphology can include nitrogen-fixing heterocysts and/or resting cells called akinetes. Formerly called blue-green algae, cyanobacteria were traditionally treated as ALGAE.
ANIMALS whose GENOME has been altered by GENETIC ENGINEERING, or their offspring.
A species of fruit fly much used in genetics because of the large size of its chromosomes.
That branch of medicine dealing with the studies and effects of flight through the atmosphere or in space upon the human body and with the prevention or cure of physiological or psychological malfunctions arising from these effects. (from NASA Thesaurus)
A mechanism of communication within a system in that the input signal generates an output response which returns to influence the continued activity or productivity of that system.
Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.
Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
An electrical current applied to the HEART to terminate a disturbance of its rhythm, ARRHYTHMIAS, CARDIAC. (Stedman, 25th ed)
A genus of ascomycetous fungi, family Sordariaceae, order SORDARIALES, comprising bread molds. They are capable of converting tryptophan to nicotinic acid and are used extensively in genetic and enzyme research. (Dorland, 27th ed)
A melatonin receptor subtype primarily found expressed in the BRAIN and RETINA.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.
Ventral part of the DIENCEPHALON extending from the region of the OPTIC CHIASM to the caudal border of the MAMMILLARY BODIES and forming the inferior and lateral walls of the THIRD VENTRICLE.
A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.
Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
An anterior pituitary hormone that stimulates the ADRENAL CORTEX and its production of CORTICOSTEROIDS. ACTH is a 39-amino acid polypeptide of which the N-terminal 24-amino acid segment is identical in all species and contains the adrenocorticotrophic activity. Upon further tissue-specific processing, ACTH can yield ALPHA-MSH and corticotrophin-like intermediate lobe peptide (CLIP).
Inorganic compounds that contain lithium as an integral part of the molecule.
Proteins that originate from plants species belonging to the genus ARABIDOPSIS. The most intensely studied species of Arabidopsis, Arabidopsis thaliana, is commonly used in laboratory experiments.
The interactions between the anterior pituitary and adrenal glands, in which corticotropin (ACTH) stimulates the adrenal cortex and adrenal cortical hormones suppress the production of corticotropin by the anterior pituitary.
Warm-blooded vertebrate animals belonging to the class Mammalia, including all that possess hair and suckle their young.

Effects of dispersed recreational activities on the microbiological quality of forest surface water. (1/9125)

The microbiological quality of forest surface waters in the Greenwater River watershed was examined to investigate the influence of heavy motorized camping in an area with no sanitary facilities. Indicator densities increased during weekend human-use periods when compared to weekdays. Increases in indicator densities were also noted downstream from heavily used camping areas when compared to upstream sites. Seasonal, weekly, and diurnal fluctuations in indicator densities were observed. This study suggests that potential health hazards exist in this watershed during periods of human use.  (+info)

High-linoleate and high-alpha-linolenate diets affect learning ability and natural behavior in SAMR1 mice. (2/9125)

Semipurified diets incorporating either perilla oil [high in alpha-linolenate, 18:3(n-3)] or safflower oil [high in linoleate, 18:2(n-6)] were fed to senescence-resistant SAMR1 mouse dams and their pups. Male offspring at 15 mo were examined using behavioral tests. In the open field test, locomotor activity during a 5-min period was significantly higher in the safflower oil group than in the perilla oil group. Observations of the circadian rhythm (48 h) of spontaneous motor activity indicated that the safflower oil group was more active than the perilla oil group during the first and second dark periods. The total number of responses to positive and negative stimuli was higher in the safflower oil group than in the perilla oil group in the light and dark discrimination learning test, but the correct response ratio was lower in the safflower oil group. The difference in the (n-6)/(n-3) ratios of the diets reflected the proportions of (n-6) polyunsaturated fatty acids, rather than those of (n-3) polyunsaturated fatty acids in the brain total fatty acids, and in the proportions of (n-6) and (n-3) polyunsaturated fatty acids in the total polyunsaturated fatty acids of the brain phospholipids. These results suggest that in SAMR1 mice, the dietary alpha-linolenate/linoleate balance affects the (n-6)/(n-3) ratio of brain phospholipids, and this may modify emotional reactivity and learning ability.  (+info)

Alteration of circadian time structure of blood pressure caused by night shift schedule. (3/9125)

The effects of night shift schedules on circadian time structure of blood pressure were studied in seven healthy young subjects by continuous monitoring of blood pressure every 30 min for 72 h. In the control experiment, subjects were instructed to sleep at regular times with the light off at 00.00 h and the light on at 07.00 h. In the shift experiment, they were instructed to go to bed at 06.00 h and wake up at 11.00 h. The circadian rhythm of blood pressure rapidly phase delayed by 3.5 h in the second night shift day as a group phenomenon. Individual differences in changes in power spectral patterns of blood pressure were found in the night shift schedule. Ultradian rhythmicity of blood pressure was more pronounced in three subjects, whereas the circadian rhythmicity was maintained in four subjects. These findings held when the adaptation to shift work was taken into account.  (+info)

Circadian variation in the expression of cell-cycle proteins in human oral epithelium. (4/9125)

At the tissue level, there is experimental and clinical data to suggest a cytokinetic coordination of the cell cycle with a greater proportion of cycling cells entering S-phase and mitosis at specific times of the day. The association of certain cell-cycle proteins with defined events in the cell cycle is well established and may be used to study the timing of cell-cycle phases over 24 hours. In this study oral mucosal biopsies were obtained from six normal human volunteers at 4-hour intervals, six times over 24 hours. Using immunohistochemistry, the number of positive cells expressing the proteins p53, cyclin-E, cyclin-A, cyclin-B1, and Ki-67 was determined for each biopsy and expressed as the number of positive cells per mm of basement membrane. We found a statistically significant circadian variation in the nuclear expression of all of these proteins with the high point of expression for p53 at 10:56 hours, cyclin-E at 14:59 hours, cyclin-A at 16:09 hours, cyclin-B1 at 21:13 hours, and Ki-67 at 02:50 hours. The circadian variation in the nuclear expression of cyclins-E (G1/S phase), -A (G2-phase), and -B1 (M-phase) with a normal physiological progression over time suggests a statistically significant circadian variation in oral epithelial cell proliferation. The finding of a circadian variation in the nuclear expression of p53 protein corresponding to late G1 is novel. This information has clinical implications regarding the timing of chemotherapy and radiotherapy.  (+info)

The biological clock of very premature primate infants is responsive to light. (5/9125)

Each year more than 250,000 infants in the United States are exposed to artificial lighting in hospital nurseries with little consideration given to environmental lighting cycles. Essential in determining whether environmental lighting cycles need to be considered in hospital nurseries is identifying when the infant's endogenous circadian clock becomes responsive to light. Using a non-human primate model of the developing human, we examined when the circadian clock, located in the hypothalamic suprachiasmatic nuclei (SCN), becomes responsive to light. Preterm infant baboons of different ages were exposed to light (5,000 lux) at night, and then changes in SCN metabolic activity and gene expression were assessed. After exposure to bright light at night, robust increases in SCN metabolic activity and gene expression were seen at ages that were equivalent to human infants at 24 weeks after conception. These data provide direct evidence that the biological clock of very premature primate infants is responsive to light.  (+info)

Effects of different light intensities during the daytime on circadian rhythm of core temperature in humans. (6/9125)

The present study was to determine the effects of bright light exposure during the daytime on core temperature rhythm. Eight female students participated as subjects. They were exposed to bright light of 5000 lux or dim light of 200 lux for 13 hours (06:30-19:30) for two consecutive days. Except the sleep period (22:30-06:30) and during the bright light exposure, light intensity was controlled at 200 lux. Rectal temperature data were collected every 10 min throughout the whole experimental period. The mean level of rectal temperature was not significantly different between the bright and the dim light conditions. However, the evening fall and the morning rise of rectal temperature were significantly greater in the bright light conditions on Day 2 compared to the dim. Furthermore, cosinor analysis showed that the acrophase of rectal temperature rhythm was earlier on Day 2 in the bright light conditions than the dim, and was significantly delayed on Day 2 compared to Day 1 in the dim light conditions. These results suggest that low intensity during the daytime for two consecutive days may induce a phase delay of core temperature rhythm rather than the bright light exposure at least in normally entrained female subjects.  (+info)

Ambulatory blood pressure monitoring and progression in patients with IgA nephropathy. (7/9125)

BACKGROUND: Hypertension is a recognized marker of poor prognosis in IgA nephropathy. METHODS: The present study investigated the prevalence of white-coat hypertension, the diurnal rhythm of blood pressure (BP), the effectiveness of antihypertensive drug therapy, and the effect of the above on the progression of the kidney disease in IgA nephropathy. One hundred twenty-six IgA nephropathy patients were selected consecutively for 24-h ambulatory blood pressure monitoring (ABPM). Fifty-five patients were normotensive and 71 were treated hypertensives. Their antihypertensive drugs were angiotensin-converting enzyme inhibitors (ACEI) alone or in combination with calcium-channel blockers (CCB). RESULTS: The mean night-time BP of normotensives (108+/-9/67+/-6 mmHg) was significantly lower than their day-time BP (125+/-8/82+/-7 mmHg, P<0.05). There was no significant difference between the mean day-time and night-time BP in hypertensive patients (125+/-9/82+/-7 mmHg vs 128+/-10/85+/-9 mmHg). The circadian variation of BP was preserved ('dippers') in 82% of the normotensive and 7% of the hypertensive patients (P<0.001). There were 10 'white-coat hypertensives' among the patients classified as normotensives with ABPM (mean office blood pressure 149+/-7/96+/-8 mmHg, 24-h blood pressure 127+/-6/83+/-5 mmHg, P<0.05) and 14 among treated hypertensives (mean office BP 152+/-8/98+/-6 mmHg, 24-h BP 130+/-4/85+/-8 mmHg, P<0.05). There was no difference in mean day-time BP among normotensive and treated hypertensive patients (125+/-8/81+/-5 mmHg vs 128+/-10/85+/-9 mmHg). Hypertensives had significantly higher night-time BP (125+/-9/85+/-9 mmHg) than normotensives (108+/-9/67+/-6 mmHg, P<0.001). There was no difference in serum creatinine levels among the different groups at the time of the ABPM. However, thirty-six+/-4.1 months after the ABPM, hypertensive patients (n=52) had higher serum creatinine levels (124+/-32 micromol/l) than at the time of the ABPM (101+/-28 micromol/l). The serum creatinine of normotensive patients (n=43) did not change during the follow-up period. 'Non-dipper' normotensives (n=10) had significantly higher serum creatinine levels at the end of the follow-up period than at its beginning (106+/-17 micromol/l vs 89+/-18 micromol/l, P<0.05). There was no increase in serum creatinine of 'dipper' normotensives. The mean serum creatinine of 'white-coat hypertensives' was significantly higher at the end of the study period than at its beginning. CONCLUSIONS: There is no diurnal blood pressure variation in most of the hypertensive IgA nephropathy patients. ACEI and CCB treatment have better effect on day-time than night-time hypertension. The lack of the circadian rhythm and 'white-coat hypertension' seems to accelerate the progression of IgA nephropathy.  (+info)

Diurnal variation and age differences in the biochemical markers of bone turnover in horses. (8/9125)

Biochemical markers of bone turnover provide sensitive, rapid, and noninvasive monitoring of bone resorption and formation. Serum concentrations of osteocalcin (OC) reflect rates of bone formation, and urinary concentrations of the pyridinium crosslinks pyridinoline (Pyd) and deoxypyridinoline (Dpd) are specific and sensitive markers of bone resorption. These markers are age-dependent and are used to detect and monitor changes in the rates of bone turnover in a variety of orthopedic diseases in humans and may prove to have similar application in horses. This study examined age differences and diurnal variation in OC, Pyd, and Dpd in eight adult geldings and seven weanling colts. Blood and urine were collected at regular intervals over 24 h. Serum OC and cortisol, and urinary Pyd and Dpd were analyzed. Mean 24-h concentrations of cortisol and all three markers were higher (P<.003) in weanlings than adults. Significant 24-h variation was observed in adult gelding OC, Pyd, and Dpd concentrations (P< .02). Adult OC concentrations were highest between 2400 and 0900; Pyd and Dpd peaked between 0200 and 0800. Similar patterns of bone turnover were observed in weanling values, but they were not significant (P>.17) owing to greater variability between individuals. Cortisol secretion varied (P<.001) over 24 h in both adults and weanlings and, thus, did not seem to be responsible for greater variability in markers of bone turnover between weanlings. These data demonstrate that diurnal rhythms exist for serum OC and urinary Pyd and Dpd in adult horses, as reported in humans, and that sample timing is an important consideration in future equine studies using these markers.  (+info)

Circadian rhythms modulate growth and development in all organisms through interlocking transcriptional-translational feedback loops. The transcriptional loop involves chromatin modifications of central circadian oscillators in mammals and plants. However, the molecular basis for rhythmic epigenetic modifications and circadian regulation is poorly understood. Here we report a feedback relationship between diurnal regulation of circadian clock genes and histone modifications in Arabidopsis. On one hand, the circadian oscillators CCA1 and LHY regulate diurnal expression of genes coding for the eraser (JMJ14) directly and writer (SDG2) indirectly for H3K4me3 modification, leading to rhythmic H3K4me3 changes in target genes. On the other hand, expression of circadian oscillator genes including CCA1 and LHY is associated with H3K4me3 levels and decreased in the sdg2 mutant but increased in the jmj14 mutant. At the genome-wide level, diurnal rhythms of H3K4me3 and another histone mark H3K9ac are associated
To screen for output signals that may distinguish the pacemaker in the mammalian suprachiasmatic nucleus (SCN) from peripheral-type oscillators in which the canonical clockworks are similarly regulated in a circadian manner, the rhythmic behavior of the transcriptome in forskolin-stimulated NIH/3T3 fibroblasts was analyzed and compared relative to SCN2.2 cells in vitro and the rat SCN. Similar to the circadian profiling of the SCN2.2 and rat SCN transcriptomes, NIH/3T3 fibroblasts exhibited circadian fluctuations in the expression of the core clock genes, Per2, Cry1, and Bmal1, and 323 functionally diverse transcripts, many of which regulate cellular communication. Overlap in rhythmic transcripts among NIH/3T3 fibroblasts, SCN2.2 cells, and the rat SCN was limited to these clock genes and four other genes that mediate fatty acid and lipid metabolism or function as nuclear factors. Compared with NIH/3T3 cells, circadian gene expression in SCN oscillators was more prevalent among genes mediating ...
TY - JOUR. T1 - Inhibition of protein kinase A phase delays the mammalian circadian clock. AU - Lee, Jennifer M.. AU - Schak, Kathryn M.. AU - Harrington, Mary E.. PY - 1999/7/24. Y1 - 1999/7/24. N2 - The suprachiasmatic nuclei (SCN) contain the mammalian circadian clock whose rhythm of firing rate can be recorded in vitro for several days. Application of a protein kinase A (PKA) inhibitor onto the SCN at Zeitgeber time (ZT) 10 on the first day in vitro phase delayed the rhythm of firing rate expressed by SCN neurons on the subsequent day in vitro. Application of the inhibitor (Rp-cAMPS) at other circadian phases did not phase shift the rhythm. These results suggest that during approximately 1 h in the late subjective day the presence and activity of PKA plays a role in setting the phase of the mammalian circadian clock.. AB - The suprachiasmatic nuclei (SCN) contain the mammalian circadian clock whose rhythm of firing rate can be recorded in vitro for several days. Application of a protein ...
Circadian systems represent an endogenous mechanism adapted to cycling environmental conditions. In mammals, the central circadian clock is located in the suprachiasmatic nuclei (SCN), guiding circadian-regulated biological variables such as the sleep-wake cycle, hormonal secretions and locomotor activity [1]. Another physiological process that exhibits circadian fluctuations, with obvious implications in disease progression and outcome, is the regulation of immune function.. The link between the circadian and the immune systems has been extensively investigated [2-4]. Circadian rhythms within the immune system were described in several tissues and cellular populations [5]. In humans, the number of lymphocytes and granulocytes peaks during the night, whereas monocytes and neutrophil levels fall during the day [6]. Major humoral immune responses undergo circadian changes, and rhythms in plasmatic levels of pro-inflammatory cytokines, as well as peptide hormones produced and secreted by immune ...
Circadian phase resetting in older people by ocular bright light exposure.. Aging is associated with frequent complaints about earlier bedtimes and waketimes. These changes in sleep timing are associated with an earlier timing of multiple endogenous rhythms, including core body temperature (CBT) and plasma melatonin, driven by the circadian pacemaker. One possible cause of the age-related shift of endogenous circadian rhythms and the timing of sleep relative to clock time is a change in the phase-shifting capacity of the circadian pacemaker in response to the environmental light-dark cycle, the principal synchronizer of the human circadian system. METHODS: We studied the response of the circadian system of 24 older men and women and 23 young men to scheduled exposure to ocular bright light stimuli. Light stimuli were 5 hours in duration, administered for 3 consecutive days at an illuminance of approximately 10,000 lux. Light stimuli were scheduled 1.5 or 3.5 hours after the CBT nadir to induce ...
In the context of bacterial circadian rhythms, specifically in cyanobacteria, circadian advantage refers to the improved survival of strains of cyanobacteria that resonate with the environmental circadian rhythm. [6] For example, consider a strain with a free-running period (FRP) of 24 hours is co-cultured with a strain that has a free-running period (FRP) of 30 hours in a light-dark cycle of 12 hours light and 12 hours dark (LD 12:12). The strain that has a 24 hour FRP will out-compete the 30 hour strain over time. An instance where bacterial circadian rhythms are theorized to provide an advantage is in the microbiome. It is possible that circadian clocks play a role in the gut microbiota behavior. These microorganisms experience daily changes associated with daily LD and temperature cycles through an alteration of their environment. This occurs through behaviors such as eating rhythms on a daily routine (consumption in the day for diurnal animals and in the night for nocturnal). The presence ...
Sleep and circadian rhythm disruption (SCRD) and schizophrenia are often co-morbid. Here, we propose that the co-morbidity of these disorders stems from the involvement of common brain mechanisms. We summarise recent clinical evidence that supports this hypothesis, including the observation that the treatment of SCRD leads to improvements in both the sleep quality and psychiatric symptoms of schizophrenia patients. Moreover, many SCRD-associated pathologies, such as impaired cognitive performance, are routinely observed in schizophrenia. We suggest that these associations can be explored at a mechanistic level by using animal models. Specifically, we predict that SCRD should be observed in schizophrenia-relevant mouse models. There is a rapidly accumulating body of evidence which supports this prediction, as summarised in this review. In light of these emerging data, we highlight other models which warrant investigation, and address the potential challenges associated with modelling schizophrenia and
All domains of life feature diverse molecular clock machineries that synchronize physiological processes to diurnal environmental fluctuations. However, no mechanisms are known to cross-regulate prokaryotic and eukaryotic circadian rhythms in multikingdom ecosystems. Here, we show that the intestinal microbiota, in both mice and humans, exhibits diurnal oscillations that are influenced by feeding rhythms, leading to time-specific compositional and functional profiles over the course of a day. Ablation of host molecular clock components or induction of jet lag leads to aberrant microbiota diurnal fluctuations and dysbiosis, driven by impaired feeding rhythmicity. Consequently, jet-lag-induced dysbiosis in both mice and humans promotes glucose intolerance and obesity that are transferrable to germ-free mice upon fecal transplantation. Together, these findings provide evidence of coordinated metaorganism diurnal rhythmicity and offer a microbiome-dependent mechanism for common metabolic ...
Background AMP protein kinase (AMPK) plays an important role in food intake and energy metabolism, which are synchronized to the light-dark cycle. In vitro, AMPK affects the circadian rhythm by regulating at least two clock components, CKIα and CRY1, via direct phosphorylation. However, it is not known whether the catalytic activity of AMPK actually regulates circadian rhythm in vivo. Methodology/Principal Finding The catalytic subunit of AMPK has two isoforms: α1 and α2. We investigate the circadian rhythm of behavior, physiology and gene expression in AMPKα1−/− and AMPKα2−/− mice. We found that both α1−/− and α2−/− mice are able to maintain a circadian rhythm of activity in dark-dark (DD) cycle, but α1−/− mice have a shorter circadian period whereas α2−/− mice showed a tendency toward a slightly longer circadian period. Furthermore, the circadian rhythm of body temperature was dampened in α1−/− mice, but not in α2−/− mice. The circadian pattern of core
Epicardial fat tissue is known to have an unique endocrine function which affect the cardiac autonomic system. Heart rate recovery (HRR) is a simple non-invasive measurement that assesses autonomic nervous system dysfunction. We aimed to investigate the association among epicardial fat thickness (EFT), HRR and circadian blood pressure (BP) variation in patients with hypertension. A total of 358 consecutive patients who underwent both 24-hour ambulatory BP monitoring (ABPM) and a treadmill test were enrolled. Echocardiographic EFT and HRR, defined as peak heart rate minus heart rate after a 1-min recovery time, were measured. Patients were classified according to the ABPM; 147 patients with hypertension with a dipping pattern at night (dippers), 140 patients with hypertension with a non-dipping pattern at night (non-dippers) and 71 normotensive controls. EFT was significantly higher in hypertensive patients, especially in the non-dipper group, compared to the controls (non-dippers, 7.5 ± 2.9 mm; dippers
The role of DOMINO in regulation of circadian rhythms in Drosophila. Most organisms on earth use circadian clocks to modulate their bodily functions, thus adapting their metabolism, physiology and behavior to these daily environmental cycles. Malfunctions of circadian clocks are correlated with many human diseases. For example, disrupted circadian rhythms in shift workers are thought to increase the prevalence of cancers, cardiovascular diseases, diabetes and other metabolic diseases. Circadian clocks control rhythmic expression of around 10-15% of mammalian transcripts. The fruit fly Drosophila melanogaster is an excellent model to study circadian clock because of its well-characterized genome, powerful genetics tools, and high throughput automated behavioral assays. In addition, the core of the circadian pacemaker is highly conserved among species, and the molecular mechanisms of circadian clocks were, in great part, discovered in Drosophila. Studying circadian rhythms in Drosophila has ...
The adrenal cortex has a molecular clock that generates circadian rhythms in glucocorticoid production, yet it is unclear how the clock responds to acute stress. We hypothesized that stress-induced ACTH provides a signal that phase shifts the adrenal clock. To assess whether acute stress phase shifts the adrenal clock in vivo in a phase-dependent manner, mPER2::LUC mice on a 12:12h light:dark cycle underwent restraint stress for 15 min or no stress at zeitgeber time (ZT) 2 (early subjective day) or at ZT16 (early subjective night). Adrenal explants from mice stressed at ZT2 showed mPER2::LUC rhythms that were phase-advanced by ~2h, whereas adrenals from mice stressed at ZT16 showed rhythms that were phase-delayed by ~2h. The biphasic response also was observed in mice injected subcutaneously either with saline or with ACTH at ZT2 or ZT16. Blockade of the ACTH response with the glucocorticoid, dexamethasone, prevented restraint stress-induced phase shifts in the mPER2::LUC rhythm both at ZT2 and at ZT16.
Circadian rhythms in physiology and behavior are observed in almost all phyla. Genetically encoded internal clocks generate such rhythms. Identification of gene products required for the generation and maintenance of endogenous circadian near 24-hr rhythms has led to a paradigm of multiple interlocked transcriptional/translational feedback loops as the basis for molecular circadian oscillators in all studied model systems. Protein phosphorylation plays an essential role, regulating the stability, activity and subcellular localization of proteins that constitute the biological clock. This study investigates the role of the protein kinase Doubletime, a Drosophila ortholog of casein kinase Is, in the fruit fly circadian clock. For the first time enzymatically active Doubletime protein is produced and direct phosphorylation of clock protein Period is demonstrated. Phosphorylation sites are identified and their functional significance is tested in a cell culture system. An in vivo analysis of a Period mutant
Circadian rhythm is an internal biological clock, which enables to sustain an approximately 24-hour rhythm in the absence of environmental cues. In mammals, the circadian clock mechanism consists of cell-autonomous transcription-translation feedback loops that drive rhythmic, 24-hour expression patterns of core clock components. The first negative feedback loop is a rhythmic transcription of period genes (PER1, PER2, and PER3) and chryptochrome genes (CRY1 and CRY2). PER and CRY proteins form a heterodimer, which acts on the CLOCK/BMAL1 heterodimer to repress its own transcription. PER and CRY proteins are phosphorylated by casein kinase epsilon (CKIepsilon), which leads to degradation and restarting of the cycle. The second loop is a positive feedback loop driven by the CLOCK/BMAL1 heterodimer, which initiates transcription of target genes containing E-box cis-regulatory enhancer sequences ...
Circadian clocks are endogenous timekeeping systems that adapt in an anticipatory fashion the physiology and behavior of most living organisms. In mammals, the master pacemaker resides in the suprachiasmatic nucleus and entrains peripheral clocks using a wide range of signals that differentially schedule physiology and gene expression in a tissue-specific manner. The peripheral clocks, such as those found in the liver, are particularly sensitive to rhythmic external cues like feeding behavior, which modulate the phase and amplitude of rhythmic gene expression. Consequently, the liver clock temporally tunes the expression of many genes involved in metabolism and physiology. However, the circadian modulation of cellular functions also relies on multiple layers of posttranscriptional and posttranslational regulation. Strikingly, these additional regulatory events may happen independently of any transcriptional oscillations, showing that complex regulatory networks ultimately drive circadian output
The effects of aging on thyroxine and cortisol responses to low ambient temperatures and on circadian rhythm of cortisol in the ...
Circadian clocks allow organisms to organize behavior and physiology to an approximately 24-hour rhythm, facilitating adaptation to the environmental cycle of day and night. Although circadian rhythms in mammals are most evident at an organismal level, circadian timekeeping occurs cell-autonomously (1). The clock in every cell and tissue is synchronized in vivo by systemic cues such as body temperature and glucocorticoid signaling, which are themselves coordinated by a master clock in the hypothalamic suprachiasmatic nuclei (2). There is mounting evidence that circadian disruption, associated with modern lifestyles and aging, contributes to morbidities as diverse as cancer, cardiovascular disease, and diabetes (3, 4). A major knowledge gap exists, however, between the well-characterized circadian gene expression rhythms that occur in healthy peripheral tissues in vivo and the way in which different cell types exploit their innate clockwork to achieve beneficial circadian regulation of cell ...
Circadian rhythms allow organisms to anticipate and prepare for precise and regular environmental changes. They thus enable organisms to better capitalize on environmental resources (e.g. light and food) compared to those that cannot predict such availability. It has therefore been suggested that circadian rhythms put organisms at a selective advantage in evolutionary terms. However, rhythmicity appears to be as important in regulating and coordinating internal metabolic processes, as in coordinating with the environment.[18] This is suggested by the maintenance (heritability) of circadian rhythms in fruit flies after several hundred generations in constant laboratory conditions,[19] as well as in creatures in constant darkness in the wild, and by the experimental elimination of behavioral, but not physiological, circadian rhythms in quail.[20][21]. What drove circadian rhythms to evolve has been an enigmatic question. Previous hypotheses emphasized that photosensitive proteins and circadian ...
Sleep and circadian rhythm disruption has been widely observed in neuropsychiatric disorders including schizophrenia [1] and often precedes related symptoms [2] . However, mechanistic basis for this association remains unknown. Therefore, we investigated the circadian phenotype of blind-drunk (Bdr), a mouse model of synaptosomal-associated protein (Snap)-25 exocytotic disruption that displays schizophrenic endophenotypes modulated by prenatal factors and reversible by antipsychotic treatment [3, 4]. Notably, SNAP-25 has been implicated in schizophrenia from genetic [5-8] , pathological [9-13], and functional studies [14-16] . We show here that the rest and activity rhythms of Bdr mice are phase advanced and fragmented under a light/dark cycle, reminiscent of the disturbed sleep patterns observed in schizophrenia. Retinal inputs appear normal in mutants, and clock gene rhythms within the suprachiasmatic nucleus (SCN) are normally phased both in vitro and in vivo. However, the 24 hr rhythms of arginine
Circadian rhythms, the biological oscillations based around our 24-hour clock, have a profound effect on human physiology and healthy cellular function. Circadian Rhythms: Health and Disease is a wide-ranging foundational text that provides students and researchers with valuable information on the molecular and genetic underpinnings of circadian rhythms and looks at the impacts of disruption in our biological clocks in health and disease.. Circadian Rhythms opens with chapters that lay the fundamental groundwork on circadian rhythm biology. Section II looks at the impact of circadian rhythms on major organ systems. Section III then turns its focus to the central nervous system. The book then closes with a look at the role of biological rhythms in aging and neurodegeneration.. Written in an accessible and informative style, Circadian Rhythms: Health and Disease,will be an invaluable resource and entry point into this fascinating interdisciplinary field that brings together aspects of ...
Nearly all organisms living near the surface of the Earth contain circadian (circa - about; diem- day) clocks functioning as an endogenous timekeeping mechanism by which the organism can coordinate biological processes with 24h cycles in the external environment (such as the daily light:dark cycle). In nature, the ~24h free-running oscillation of circadian clocks is synchronized or entrained with the precisely 24h solar day cycle. In mammals, the master circadian pacemaker is located in the hypothalamic suprachiasmatic nucleus (SCN) which regulates ~24h rhythms of biological activity. The master circadian pacemaker within the SCN modulates adrenal gland release of glucocorticoids (GCs). GCs are a class of steroids critical for the mobilization of energy throughout the organism. GCs are released from the adrenal cortex and exhibit a circadian oscillation anticipating the onset of locomotor activity. In addition to humoral input to the adrenal cortex via adrenocorticotropic hormone (ACTH), the ...
Circadian activity rhythms in hamsters are entrained to the daily light:dark cycle by photic information arriving from the retina to the suprachiasmatic nucleus, the site of the master circadian pacemaker in mammals. The effects of light on adjusting the timing of the circadian pacemaker is modified …
Circadian rhythms, the subset of endogenous rhythms with a period of approximately 24 h, are widely encountered in most organisms from cyanobacteria to humans. Although eukaryotes employ a common mechanistic logic of interlocked negative feedback loops to generate robust circadian oscillations, different components have been recruited to form the clock in different taxa (Bell-Pedersen et al., 2005; McClung, 2006; Wijnen and Young, 2006). Thus, fungal, animal, and plant clocks share a common architectural plan yet are composed of largely distinct components. This suggestion of polyphyletic origins of clocks implies strong selection for clock function. Indeed, in many organisms, including cyanobacteria, fruit fly, ground squirrel, and Arabidopsis (Arabidopsis thaliana), experimental evidence indicates that a robust circadian clock whose period resonates with the environmentally imposed diurnal cycle confers a fitness advantage (Yerushalmi and Green, 2009).. Among plants, most that is known about ...
Circadian rhythms, the subset of endogenous rhythms with a period of approximately 24 h, are widely encountered in most organisms from cyanobacteria to humans. Although eukaryotes employ a common mechanistic logic of interlocked negative feedback loops to generate robust circadian oscillations, different components have been recruited to form the clock in different taxa (Bell-Pedersen et al., 2005; McClung, 2006; Wijnen and Young, 2006). Thus, fungal, animal, and plant clocks share a common architectural plan yet are composed of largely distinct components. This suggestion of polyphyletic origins of clocks implies strong selection for clock function. Indeed, in many organisms, including cyanobacteria, fruit fly, ground squirrel, and Arabidopsis (Arabidopsis thaliana), experimental evidence indicates that a robust circadian clock whose period resonates with the environmentally imposed diurnal cycle confers a fitness advantage (Yerushalmi and Green, 2009).. Among plants, most that is known about ...
TY - JOUR. T1 - Investigating the relationships between hypothalamic volume and measures of circadian rhythm and habitual sleep in premanifest Huntingtons disease. AU - Bartlett, Danielle M.. AU - Domínguez D, Juan F.. AU - Reyes, Alvaro. AU - Zaenker, Pauline. AU - Feindel, Kirk W.. AU - Newton, Robert U.. AU - Hannan, Anthony J.. AU - Slater, James A.. AU - Eastwood, Peter R.. AU - Lazar, Alpar S.. AU - Ziman, Mel. AU - Cruickshank, Travis. PY - 2019/1. Y1 - 2019/1. N2 - Objective: Pathological changes within the hypothalamus have been proposed to mediate circadian rhythm and habitual sleep disturbances in individuals with Huntingtons disease (HD). However, investigations examining the relationships between hypothalamic volume and circadian rhythm and habitual sleep in individuals with HD are sparse. This study aimed to comprehensively evaluate the relationships between hypothalamic pathology and circadian rhythm and habitual sleep disturbances in individuals with premanifest HD. Methods: ...
OBJECTIVE: Physical activity and circadian rhythms are well-established determinants of human health and disease, but the relationship between muscle activity and the circadian regulation of muscle genes is a relatively new area of research. It is unknown whether muscle activity and muscle clock rhythms are coupled together, nor whether activity rhythms can drive circadian gene expression in skeletal muscle. METHODS: We compared the circadian transcriptomes of two mouse hindlimb muscles with vastly different circadian activity patterns, the continuously active slow soleus and the sporadically active fast tibialis anterior, in the presence or absence of a functional skeletal muscle clock (skeletal muscle-specific Bmal1 KO). In addition, we compared the effect of denervation on muscle circadian gene expression. RESULTS:We found that different skeletal muscles exhibit major differences in their circadian transcriptomes, yet core clock gene oscillations were essentially identical in fast and slow ...
Hazlerigg, DG, Ebling, FJP and Johnston, JD (2005) Photoperiod differentially regulates gene expression rhythms in the rostral and caudal SCN ...
Purpose : Changes in eye growth that lead to myopia or hyperopia are associated with alterations in the circadian rhythms in eye length and choroidal thickness in animal models. Recent studies have shown that light at night has deleterious effects on human health via circadian disruptions in various physiological rhythms. The purpose of this study was to determine the effects of 2-hour episodes of light at night on the rhythms in axial length and choroidal thickness, and on growth rate and refraction in the chick model. Methods : At 2 weeks of age, birds received light (700 lux) between 12:00 am and 2:00 am for 7 days (n=18; total light=14 hr). Age-matched controls had a continuous dark night (n=22; 14L/10D). Ocular dimensions were measured using high-frequency A-scan ultrasonography on the first day, and again on day 7 at 6-hr intervals for 24 hr, starting at noon. Measurements during the night used a photographic safe-light. These data were used to determine rhythm parameters of phase and ...
Synchrony of the mammalian circadian clock is achieved by complex transcriptional and translational feedback loops centered on the BMAL1:CLOCK heterodimer. Modulation of circadian feedback loops is essential for maintaining rhythmicity, yet the role of transcriptional coactivators in driving BMAL1:CLOCK transcriptional networks is largely unexplored. Here, we show diurnal hepatic steroid receptor coactivator 2 (SRC-2) recruitment to the genome that extensively overlaps with the BMAL1 cistrome during the light phase, targeting genes that enrich for circadian and metabolic processes. Notably, SRC-2 ablation impairs wheel-running behavior, alters circadian gene expression in several peripheral tissues, alters the rhythmicity of the hepatic metabolome, and deregulates the synchronization of cell-autonomous metabolites. We identify SRC-2 as a potent coregulator of BMAL1:CLOCK and find that SRC-2 targets itself with BMAL1:CLOCK in a feedforward loop. Collectively, our data suggest that SRC-2 is a ...
Circadian rhythms are essential for healthful cardiovascular physiology and so are regulated on the molecular level with a circadian clock mechanism. and BMAL1 targeted Bardoxolone genes using the CircaDB JTK_Cycle and internet site. Furthermore 22 were expressed in the center as dependant on the BioGPS internet site highly. Furthermore 5 Bardoxolone heart-enriched genes acquired individual/mouse conserved CLOCK:BMAL1 promoter binding sites (E-boxes) as dependant on UCSC table web browser circadian mammalian promoter/enhancer data source PEDB as well Bardoxolone as the Western european Bioinformatics Institute position tool (EMBOSS). Finally we validated results by demonstrating that (mRNA and TCAP protein experienced a diurnal rhythm in murine heart; 2) cardiac mRNA was rhythmic in animals kept in constant darkness; 3) and control mRNA manifestation and cyclic amplitude were blunted in ClockΔ19/Δ19 hearts; 4) BMAL1 certain to the promoter by ChIP assay; 5) BMAL1 certain to promoter E-boxes by ...
The rotation of the earth around its axis and the sun generates rhythmic daily and seasonal cycles in our world. Organisms have evolved a biological clock to be able to predict and follow environmental cyclic rhythms to control their physiology and behavior for survival. In mammals the master clock is located in the suprachiasmatic nucleus (SCN) of the hypothalamus which receives light inputs via retinohypothalamic tract directly from the retina to be entrained to external cycles. Circadian rhythms are maintained by two negative feedback loops involving several clock genes such as Clock, Bmal1, Period, Cryptochrome and Rev-erbα. Apart from the central master clock, there are several peripheral clocks controlling local feature of organs in synchrony with the SCN. One of these peripheral circadian oscillators is the retina which is the one that processes the light cues and may influence the circadian rhythms generated by the SCN.. We are interested how the visual system adjust itselves to the ...
The rhythmic genes we have identified under LD and DD conditions display bone fide rhythmic expression. The inclusion of seven known rhythmic genes (per, tim, vri, Clk, Dreg-2, cry, and takeout) in the set of 72 diurnally oscillating genes and four (per, tim, vri, and Clk) in the set of 22 circadianly oscillating genes provides confidence that the autocorrelation method we applied identifies rhythmic gene expression with fidelity.. The true number of circadianly regulated genes in Drosophila can only be estimated; the accuracy of any estimate depends on both methodological constraints and assumptions used in the data analysis. Our estimates of 72-200 robustly oscillating genes in LD 12:12 and a minimum of 22 genes in DD likely underestimate the true number of oscillating genes in the fly head. First, by necessity the choices of A0 minima were determined empirically. In the absence of true positive controls (i.e., rhythmically spiked foreign, polyadenylated message), we relied on the reproducible ...
In Arabidopsis thaliana, a number of circadian-associated factors have been identified, including TOC1 (TIMING OF CAB EXPRESSION 1) that is believed to be a component of the central oscillator. TOC1 is a member of a small family of proteins, designated as ARABIDOPSIS PSEUDO-RESPONSE REGULATORS (APRR1/TOC1, APRR3, APRR5, APRR7, and APRR9). As demonstrated previously, these APRR1/TOC1 quintet members are crucial for a better understanding of the molecular links between circadian rhythms, control of flowering time through photoperiodic pathways, and also photosensory signal transduction in this dicotyledonous plant. In this respect, both the dicotyledonous (e.g. A. thaliana) and monocotyledonous (e.g. Oryza sativa) plants might share the evolutionarily conserved molecular mechanism underlying the circadian rhythm. Based on such an assumption, and as the main objective of this study, we asked the question of whether rice also has a set of pseudo-response regulators, and if so, whether or not they ...
In the last 50 years, research on circadian rhythms has grown from understanding the basics to being able to map out intricate orchestrations for various systems. An article entitled Perfect timing: circadian rhythms, sleep, and immunity - an NIH workshop summary and other recent articles helps shed light on the circadian rhythms and immune health. This timely article from January 2020 gives us insight into current immune-challenging concerns. It tells us that disruption of day-night routines and circadian rhythms profoundly impacts essential immune functions and weakens health. Restoration of healthy day-night, wake-sleep routines supports your circadian rhythm and body clocks which helps immune system function and vitality ...
TY - JOUR. T1 - The relationships between clinical characteristics, alcohol and psychotropic exposure, and circadian gene expression in human postmortem samples of affective disorder and control subjects. AU - Gonzalez, Robert. AU - Bernardo, Carmina. AU - Cruz, Dianne. AU - Walss-Bass, Consuelo. AU - Thompson, Peter M.. PY - 2014/8/30. Y1 - 2014/8/30. N2 - Circadian abnormalities may be related to mood disorders. Circadian gene expression was measured in postmortem brain tissue from individuals with affective disorders and controls. Relationships between circadian gene expression, clinical characteristics, and alcohol and psychotropic medication use were noted. Further study is warranted to characterize these relationships.. AB - Circadian abnormalities may be related to mood disorders. Circadian gene expression was measured in postmortem brain tissue from individuals with affective disorders and controls. Relationships between circadian gene expression, clinical characteristics, and alcohol ...
new volumes of Methods in Enzymology proceed the legacy of this foremost serial with caliber chapters authored by means of leaders within the box. Circadian Rhythms and organic Clocks half A and half B is an outstanding source for anyone drawn to the overall region of circadian rhythms. As key parts of timekeeping are conserved in organisms around the phylogenetic tree, and our realizing of circadian biology has benefited significantly from paintings performed in lots of species, the amount offers a variety of assays for various organic systems. Protocols are supplied to evaluate clock functionality, entrainment of the clock to stimuli corresponding to mild and foodstuff, and output rhythms of habit and physiology. This quantity additionally delves into the impression of circadian disruption on human health. Contributions are from leaders within the box whove made significant discoveries utilizing the equipment awarded here.. ...
Epigenetic Modulation of Circadian Rhythms: Bmal1 Gene Regulation. By Tatsunosuke Tomita and Yoshiaki Onishi. Circadian rhythms that function in behaviour and physiology have adaptive significance for living organisms from bacteria to humans and reflect the presence of a biological clock. The engine of circadian rhythms is a transcription-translation feedback loop that is fine-tuned by epigenetic regulation in higher eukaryotes. We elucidated the chromatin structure of the Bmal1 gene, a critical component of the mammalian clock system, and have continued to investigate transcriptional regulation including DNA methylation. Various ailments including metabolic diseases can disrupt circadian rhythms, and many human diseases are associated with altered DNA methylation. Therefore, regulated circadian rhythms are important for human health. Here, we summarise the importance of epigenetic clock gene regulation, including DNA methylation of the Bmal1 gene, from the viewpoint of relationships to ...
This is the first study to show that RICTOR/mTORC2 acts as a regulator for coordinated diurnal expression of clock genes in PVAT, but not in the SCN. At the whole body level, RICTOR/mTORC2 in adipose and brain tissue contributes to the diurnal regulation of blood pressure and locomotor activity. The presented data demonstrate the importance of the mTORC2 signaling pathway in the brain to adipocyte axis for daily fluctuations of physiological processes.. We and others have recently shown that mTORC2 activity controls inflammatory molecule expression using tissue-specific Rictor knockout mouse models.7,20 We showed that vascular contractility in RictoraP2KO mice is increased because of enhanced secretion of proinflammatory cytokines in PVAT.7 Ablation of Rictor strongly reduced AKTSer473 phosphorylation, resulting in impaired mTORC2 signaling.5-7 Consequently, we assign the observed changes in RictoraP2KO mice to the impaired mTORC2 downstream signaling.. In this study, we explored these findings ...
The human sleep-wake cycle is generated by a circadian process, originating from the suprachiasmatic nuclei, in interaction with a separate oscillatory process: the sleep homeostat. The sleep-wake cycle is normally timed to occur at a specific phase relative to the external cycle of light-dark exposure. It is also timed at a specific phase relative to internal circadian rhythms, such as the pineal melatonin rhythm, the circadian sleep-wake propensity rhythm, and the rhythm of responsiveness of the circadian pacemaker to light. Variations in these internal and external phase relationships, such as those that occur in blindness, aging, morning and evening, and advanced and delayed sleep-phase syndrome, lead to sleep disruptions and complaints. Changes in ocular circadian photoreception, interindividual variation in the near-24-h intrinsic period of the circadian pacemaker, and sleep homeostasis can contribute to variations in external and internal phase. Recent findings on the physiological and molecular
Circadian entrainment is a fundamental property by which the period of the internal biological clock is entrained by recurring exogenous signals, such that the organisms endocrine and behavioral rhythms are synchronized to environmental cues. In mammals, a master clock is located in the suprachiasmatic nuclei (SCN) of the hypothalamus and may synchronize circadian oscillators in peripheral tissues. Light signal is the dominant synchronizer for master SCN clock. Downstream from the retina, glutamate and PACAP are released and trigger the activation of signal transduction cascades, including CamKII and nNOS activity, cAMP- and cGMP-dependent protein kinases, and mitogen-activated protein kinase (MAPK). Of non-photic entrainment, important phase shifting capabilities have been found for melatonin, which inhibits light-induced phase shifts through inhibition of adenylate cyclase (AC). Multiple entrainment pathways converge into CREB regulation. In turn, phosphorylated CREB activates clock gene ...
In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus constitutes the central circadian pacemaker. The SCN receives light signals from the retina and controls peripheral circadian clocks (located in the cortex, the pineal gland, the liver, the kidney, the heart, etc.). This hierarchical organization of the circadian system ensures the proper timing of physiological processes. In each SCN neuron, interconnected transcriptional and translational feedback loops enable the circadian expression of the clock genes. Although all the neurons have the same genotype, the oscillations of individual cells are highly heterogeneous in dispersed cell culture: many cells present damped oscillations and the period of the oscillations varies from cell to cell. In addition, the neurotransmitters that ensure the intercellular coupling, and thereby the synchronization of the cellular rhythms, differ between the two main regions of the SCN. In this work, a mathematical model that accounts for this heterogeneous
Disruption of two genes that control circadian rhythms can lead to diabetes, a researcher at UT Southwestern Medical Center has found in an animal study.. Mice with defective copies of the genes, called CLOCK and BMAL1, develop abnormalities in pancreatic cells that eventually render the cells unable to release sufficient amounts of insulin.. These results indicate that disruption of the daily clock may contribute to diabetes by impairing the pancreas ability to deliver insulin, said Dr. Joseph Takahashi, an investigator with the Howard Hughes Medical Institute at UT Southwestern and co-senior author of the study, which appeared in the journal Nature. Dr. Takahashi, who recently joined UT Southwestern as chairman of neuroscience, performed the research with colleagues when he was at Northwestern University.. Circadian rhythms are cyclical patterns in biological activities, such as sleeping, eating, body temperature and hormone production.. The mammalian CLOCK gene, which Dr. Takahashi ...
Introduction. World Literature Essay II: C Candidate Number: 000 119 023 Word Count:1071 Total Number of Pages: 4 The Individual vs. The Party in Darkness at Noon by Arthur Koestler Purpose Statement: The fundamental believes of the Party explained by Arthur Koestler were oppressive to the ideological believes of the individual. In return the revolution failed to reach a utopian society due to the oppression of the individual. The party describe in Darkness at Noon by Arthur Koestler represents the governmental and economic system of communism in the Soviet Union during the 1930s and 40s with the main intend of reaching a utopia in the real world. The sacrifice of the individual was necessary to carry out the will of history in the eyes of the party. The ideology of the party creates a conflict in Darkness at Noon where the ideologies of the party undermined the ideas of the grammatical fiction with a result of a failed revolution. An individual perception is needed to help the rest of ...
Organisms possess endogenous clocks that enable them to synchronize to diurnal environmental cycles and anticipate time of day. In several model systems, it is known that the circadian molecular clock consists of transcriptional/translational autoregulatory feedback loops in which clock proteins translocate to the nucleus and regulate clock gene transcription (Reppert and Weaver, 2002; Dunlap and Loros, 2005; Hardin, 2005). In Drosophila, the molecular oscillator is composed of three feedback loops which are interlocked by virtue of the CLK control of per and tim gene transcription. The first loop results in rhythmic PERIOD (PER) and TIMELESS (TIM) clock protein production, the second generates rhythms in the CLOCK (CLK) transcription factor and the third (Clockwork Orange) modulates the expression of several clock genes known to be regulated by the CLK transcription factor by binding to the E-box regulatory element (Glossop et al., 1999; Cyran et al., 2003; Glossop et al., 2003; Yu et al., ...
The present study demonstrated that under strictly controlled dietary conditions plasma levels of Hcy shows significant daily rhythmicity, which is independent of the 24-h cycle of sleep and wake, with a peak at around 2200 to 2400. Previously, similar rhythmicity in Hcy with an evening peak was reported in obese diabetic patients by Bremner et al [12] and with nocturnal peak in rats by Baydas et al [13]. We further extended these findings by demonstrating that daily rhythms exist also in normal young adults. In contrast to Hcy, there was no daily rhythmicity in methionine, leucine, isoleucine and tyrosine, in which the 24-h pattern followed both the timing of sleep and the feeding schedule.. Homocysteine is a non-protein sulfur containing amino acid, and an intermediate in the metabolism of the essential amino acid methionine. The metabolism of Hcy is accomplished by two major pathways, remethylation into methionine and transsulfuration to cystationine [14]. In remethylation, Hcy acquires a ...
This study provides critical evidence in support of the hypothesis that activation of NMDA receptors is a sufficient and necessary step in the transduction of photic information to the circadian clock located in the SCN. Previous research had demonstrated that microinjection of either NMDA antagonists or non-NMDA antagonists into the SCN region could block the phase-shifting effects of light (Colwell and Menaker, 1992) and that application of glutamate to the hypothalamic slice preparation could phase shift the SCN neuronal firing rhythm in a pattern similar to that produced by light pulses in vivo(Ding et al., 1994). Recently, we demonstrated that microinjection of NMDA into the SCN region was capable of producing both phase delays and phase advances of the circadian locomotor activity rhythm (Mintz and Albers, 1997). This paper extends that finding to demonstrate that direct application of NMDA to the SCN in vivo produces a light-like phase-response curve, that this effect is specific to NMDA ...
Diurnal Fluctuations of Symptoms Symptom Checker: Possible causes include 6-Pyruvoyl-Tetrahydropterin Synthase Deficiency. Check the full list of possible causes and conditions now! Talk to our Chatbot to narrow down your search.
Organisms face unforeseen short- and long-term changes in the environment (stressors). To defend against these changes, organisms have developed a stress system that includes the hypothalamic-pituitary-adrenal (HPA) axis, which employs glucocorticoids and the glucocorticoid receptor (GR) for signal transduction. In addition, organisms live under the strong influence of day-night cycles and, hence, have also developed a highly conserved circadian clock system for adjusting their activities to recurring environmental changes. This regulatory system creates and maintains internal circadian rhythmicity by employing a self-oscillating molecular pacemaker composed of the Clock-Bmal1 heterodimer and other transcription factors. The circadian clock consists of a central master clock in the suprachiasmatic nucleus of the brain hypothalamus and peripheral slave clocks in virtually all organs and tissues. The HPA axis and the circadian clock system communicate with each other at multiple levels. The ...
Proper timing of circadian rhythm requires stable oscillations in regulatory protein abundance and activity within a transcription-translation negative feedback loop that drives expression of circadian regulators and output genes. While their molecular functions are not fully understood, mPER1 and mPER2 have the highest amplitude oscillations of all the known core clock proteins, with almost complete degradation near the end of the subjective night in the suprachiasmatic nucleus (25). mPER2 also undergoes temporal changes in phosphorylation that reaches a zenith just prior to its destruction (25).. To study phosphorylation-mediated mPER2 degradation, a combination of cell-based assays were used. Calyculin A treatment of cultured cells resulted in the rapid phosphorylation and degradation of mPER2, suggesting that both a kinase and phosphatase regulate mPER2 net phosphorylation and stability. The present study further defines the role of CKIε in regulating mPER2 protein stability in mammals. ...
In mammals, molecular circadian rhythms are generated by autoregulatory transcriptional-translational feedback loops with PERIOD/CRYPTOCHROME containing complexes inhibiting the transcription of their own genes. Although the major circadian oscillator components seem to be identified, an increasing …
Circadian rhythm[edit]. In animals, melatonin plays an important role in the regulation of sleep-wake cycles.[35] Human infants ... Arendt J (October 2000). "Melatonin, circadian rhythms, and sleep". N. Engl. J. Med. 343 (15): 1114-16. doi:10.1056/ ... Ardura J, Gutierrez R, Andres J, Agapito T (2003). "Emergence and evolution of the circadian rhythm of melatonin in children". ... In animals, melatonin is involved in synchronizing the circadian rhythms including sleep-wake timing, blood pressure regulation ...
Circadian rhythm sleep disorder. Chronic circadian rhythm sleep disorders (CRSD)[edit]. In the management of circadian rhythm ... 1.3.3 Circadian rhythm sleep disorders and jet lag * Chronic circadian rhythm sleep disorders (CRSD) ... Zisapel, Nava (2001). "Circadian Rhythm Sleep Disorders". CNS Drugs. 15 (4): 311-328. doi:10.2165/00023210-200115040-00005. ... Light therapy which strikes the retina of the eyes is used to treat diabetic retinopathy and also circadian rhythm disorders ...
"Circadian Rhythms". *^ Fahey, Christopher D.; Zee, Phyllis C. (1 December 2006). "Circadian rhythm sleep ... The human circadian rhythm can be affected by light sources.[89][90] The effective color temperature of daylight is ~5,700K[91] ... bluish white) while tungsten lamps are ~2,700K (yellow).[92] People who have circadian rhythm sleep disorders are sometimes ... "Controlling light-dark exposure patterns, rather than sleep schedules, determines circadian phase". Sleep Med. 14 (5): 456-461 ...
Circadian rhythms. Light information received by the eyes is transmitted to the pineal gland via the circadian pacemaker (the ... Ikegami K, Iigo M and Yoshimura T. Circadian clock gene Per2 is not necessary for the photoperiodic response in mice. PLoS One ...
Regulation of Sleep and Circadian Rhythms, pp. 1-17. *^ a b c d e f g Derk-Jan Dijk & Dale M. Edgar (1999), "Circadian and ... "Cellular and Molecular Mechanisms of Circadian Rhythms in Mammals", in Turek & Zee (eds.), Regulation of Sleep and Circadian ... "Functional Genomics of Sleep and Circadian Rhythm Invited Review: Integration of human sleep-wake regulation and circadian ... An organism whose circadian clock exhibits a regular rhythm corresponding to outside signals is said to be entrained; an ...
circadian rhythm. *cognitive control and working memory (co-regulated by dopamine). *feeding and energy homeostasis ...
The retinohypothalamic tract (RHT) is a photic neural input pathway involved in the circadian rhythms of mammals.[1] The origin ... The synapse of glutamate to the SCN has been shown to cause phase shifts in circadian rhythms, discussed more in detail later. ... The SCN of the hypothalamus contains an endogenous pacemaker that regulates circadian rhythms.[5] The zeitgeber found to have ... If damage is done to this important pathway, alterations in circadian rhythms including phase shifts may occur. Studies done on ...
SCN and circadian rhythmEdit. The SCN coordinates daily timekeeping in the body and VIP plays a key role in communication ... Then it will activate gene expression pathways such as Per1 and Per2 in circadian rhythm.[11] ... Application of VIP also phase shifts the circadian rhythm of vasopressin release and neural activity. The ability of the ... See SCN and circadian rhythm below. VIP in the pituitary helps to regulate prolactin secretion; it stimulates prolactin release ...
Variations due to circadian rhythmsEdit. In humans, a diurnal variation has been observed dependent on the periods of rest and ... These observations indicate that body temperature is partially regulated by circadian rhythms. ...
"A new approach to understanding the impact of circadian disruption on human health". J Circadian Rhythms. 6: 7. doi:10.1186/ ... Main articles: Full-spectrum light, Over-illumination, and Light effects on circadian rhythm ... When those patterns are disrupted, they disrupt the natural circadian cycle. Circadian disruption may lead to numerous health ... "Chronobiology International: The Journal of Biological and Medical Rhythm Research. 25 (1): 65-81. doi:10.1080/ ...
Circadian Rhythms. Methods Mol. Biol. Methods in Molecular Biology. 362. pp. 315-27. doi:10.1007/978-1-59745-257-1_22. ISBN 978 ...
Yonah's Dream, Circadian Rhythms, Two Harmonies, Under The Rainbow, The Big Rip. Newband, Dave Eggar and Deoro, Wendy Richman, ... Circadian Rhythms. Newband. Mode Records. Throat. Jean Kopperud, clarinet, Tom Kolor, percussion. Albany Records. Shadow Waltz ... CS1 maint: discouraged parameter (link) "Circadian Rhythms". New World Records Catalog website. September 5, 2012. Retrieved ... Circadian Rhythms for cello, percussion, and two keyboards (one player) (1989) Continental Drift for horn, percussion, and two ...
"Circadian Rhythm". Retrieved December 21, 2016. New TV series dresses up local landmarks in fear and blood, ... a young woman on a journey to discover who she is and why multiple enemies want her dead in the action film Circadian Rhythm. ...
The symptoms are caused by a circadian rhythm that is out of sync with the day-night cycle of the destination, as well as the ... Jet lag was previously classified as one of the circadian rhythm sleep disorders. The condition of jet lag may last several ... Most people have an endogenous circadian rhythm that is longer than 24 hours, so lengthening a day is less troublesome than ... It does not necessarily involve the shift in circadian rhythms that cause jet lag. Travel fatigue can occur without crossing ...
Refinetti is best known as the author of Circadian Physiology, a comprehensive book on circadian rhythms (first edition: 1999; ... "Journal of Circadian Rhythms. Retrieved 2015-03-16.. *^ "Sexuality & Culture". Springer Science+Business Media. Retrieved 2015- ... "Procedures for numerical analysis of circadian rhythms". Biological Rhythm Research. 38 (4): 275-325. doi:10.1080/ ... Refinetti, Roberto (2004). "Non-stationary time series and the robustness of circadian rhythms". Journal of Theoretical Biology ...
Horne JA, Östberg O (1976). "A self-assessment questionnaire to determine morningness-eveningness in human circadian rhythms". ... While it has been suggested that circadian rhythms may change over time, including dramatic changes that turn a morning lark to ... The genetic make-up of the circadian timing system underpins the difference between early and late chronotypes, or early birds ... Morning light therapy may be helpful in shifting sleep rhythms for the night owl.[10] ...
Journal of Circadian Rhythms. 6 (1): 6. doi:10.1186/1740-3391-6-6. PMC 2391143. PMID 18445295. Archived from the original (PDF ... Main article: Circadian rhythm sleep disorder. DSPD is a disorder of the body's timing system-the biological clock. Individuals ... Taken this late, it does not, of itself, affect circadian rhythms,[31] but a decrease in exposure to light in the evening is ... "Sleeplessness and Circadian Rhythm Disorder". eMedicine World Medical Library from WebMD. Retrieved 2006-06-04. Implicit in the ...
Fetuses aged 14 to 18 weeks show a pronounced circadian rhythm in their activity level, which can be detected both by fetal ... J Circadian Rhythms. 3 (1): 5. doi:10.1186/1740-3391-3-5. PMC 1079927. PMID 15801976. Vaughan, Christopher (1996). How Life ...
... is "available to crew to optimize performance while fatigued" and helps with the disruptions in circadian rhythms and ... November 2007). "Practice parameters for the clinical evaluation and treatment of circadian rhythm sleep disorders. An American ... Zee PC, Attarian H, Videnovic A (February 2013). "Circadian rhythm abnormalities". Continuum. 19 (1 Sleep Disorders): 132-47. ...
A video showing circadian rhythms in a cucumber plant in constant conditions, similar to what de Mairan observed, can be seen ... de Mairan's paper can be accessed here, together with its analysis in the light of present views of circadian rhythms. That ... His observations and experiments also inspired the beginning of what is now known as the study of biological circadian rhythms ... In 1729, de Mairan constructed an experiment showing the existence of a circadian rhythm in plants, presumably originating from ...
Circadian Rhythm Disorder (2015) Snelwar, Glen (8 March 2015). "Circadian Rhythm Disorder". Glenn Snelwar Blog. Snelwar, Glenn ... Marco Minnemann plays drums in Circadian Rhythm Disorder (2015), which is actually another version of Minnemann's drum solo ... for Circadian Rhythm Disorder: Marco Minnemann - drums, percussion Torn Between Dimensions (2005) Acts of God (2007) A Familiar ...
Liu, Yi; Bell-Pedersen, Deborah (2017-04-27). "Circadian Rhythms in Neurospora crassa and Other Filamentous Fungi". Eukaryotic ... McClung, C. Robertson (2006-04-01). "Plant Circadian Rhythms". The Plant Cell. 18 (4): 792-803. doi:10.1105/tpc.106.040980. ... TOC1 (gene) CCA1 Circadian Clock Salomé, Patrice A.; McClung, C. Robertson (2004). "The Arabidopsis thaliana Clock". Journal of ... Matsushika, Akinori (2000). "Circadian Waves of Expression of the APRR1/TOC1 Family of Pseudo-Response Regulators in ...
McClung, C. Robertson (2006). "Plant Circadian Rhythms". The Plant Cell. 18 (4): 792-794. doi:10.1105/tpc.106.040980. PMC ... Stephan, Friedrich K; Zucker, Irving (1972). "Circadian Rhythms in Drinking Behavior and Locomotor Activity of Rats Are ... Moore, Robert; Eichler, Victor (July 1972). "Loss of a circadian adrenal corticosterone rhythm following suprachiasmatic ... and studies that showed the persistence of circadian rhythm in the South Pole and in a space lab further confirmed the ...
Chronic circadian rhythm disorders, the most common of which is delayed sleep phase disorder, may be managed by specifically- ... A further subdivision of the dyssomnias preserves the integrity of circadian rhythm sleep disorders, as was mandated by about ... Polysomnography is not routinely used in the evaluation of patients with insomnia or circadian rhythm disorders, except as ... Chronotherapy has also been prescribed for circadian rhythm disorders, though results are generally short-lived. Stimulants may ...
"Genetic basis of human circadian rhythm disorders". Experimental Neurology. Circadian rhythms and sleep disorders. 243: 28-33. ... circadian rhythm. • somitogenesis. • Notch signaling pathway. • regulation of neurogenesis. • anterior/posterior pattern ... including circadian rhythms in response to environmental stimuli". BHLH Transcription Factors in Development and Disease. ... "DEC1 and DEC2 Crosstalk between Circadian Rhythm and Tumor Progression". Journal of Cancer. 7 (2): 153-9. doi:10.7150/jca.13748 ...
"Genetic basis of human circadian rhythm disorders". Experimental Neurology. Circadian rhythms and sleep disorders. 243: 28-33. ... including circadian rhythms in response to environmental stimuli". Current Topics in Developmental Biology. 110: 339-72. doi: ... "DEC1 and DEC2 Crosstalk between Circadian Rhythm and Tumor Progression". Journal of Cancer. 7 (2): 153-9. doi:10.7150/jca.13748 ... Circadian[edit]. BHLHE41 is expressed in the suprachiasmatic nucleus with levels peaking during subjective day.[14] The gene ...
It is used as a treatment for wintertime seasonal affective disorder and in circadian rhythm disorders, such as delayed sleep ... In the management of circadian rhythm disorders such as delayed sleep phase disorder (DSPD), the timing of light exposure is ... Morning therapy has provided the best results because light in the early morning aids in regulating the circadian rhythm. ... Zisapel, Nava (2001). "Circadian Rhythm Sleep Disorders". CNS Drugs. 15 (4): 311-328. doi:10.2165/00023210-200115040-00005. ...
2003-10-29). "Transdisciplinary unifying implications of circadian findings in the 1950s". Journal of Circadian Rhythms. 1 (2 ... In the 1950s, he introduced the word circadian, which derives from the Latin about (circa) a day (diem). Franz Halberg was ... Eventually I reverted, for the same reason, to "circadian" ... CS1 maint: discouraged parameter (link) Fernholm B., Bremer K., ...
A circaseptan rhythm is a cycle consisting of 7 days in which many biological processes of life resolve. Circadian rhythm ... "Palaeochronobiology circadian rhythms, gauges of adaptive Darwinian evolution: about 7-day circaseptan rhythms, gauges of ... 1987: Circaseptan rhythm in sodium and potassium excretion in salt-sensitive and salt-resistant 'Dahl rats'". Progr Clin Biol ... 755-762 Meyer-Rochow, VB; Brown, PJ (1998). "Possible natural circaseptan rhythm in the beach beetle Chaerodes trachyscelides ...
Circadian rhythm. disorder. *Advanced sleep phase disorder. *Delayed sleep phase disorder. *Irregular sleep-wake rhythm ...
A non-rod non-cone photoreceptor in the eyes of mice, which was shown to mediate circadian rhythms, was discovered in 1991 by ... These cells do not contribute to sight directly, but are thought to support circadian rhythms and pupillary reflex. ... such as the regulation of circadian rhythms, pupillary reflex and other non-visual responses to light. Melanopsin functionally ... the master pacemaker of circadian rhythms). Melanopsin-containing ganglion cells are thought to influence these targets by ...
Rats that have been prenatally stressed have elevated basal levels and abnormal circadian rhythm of corticosterone as adults.[ ... circadian rhythm). In healthy individuals, cortisol rises rapidly after wakening, reaching a peak within 30-45 minutes. It then ... This corresponds to the rest-activity cycle of the organism.[3] An abnormally flattened circadian cortisol cycle has been ... Koehl M, Darnaudéry M, Dulluc J, Van Reeth O, Le Moal M, Maccari S (September 1999). "Prenatal stress alters circadian activity ...
"Circadian Rhythm Sleep Disorder" (PDF). American Academy of Sleep Medicine. 2008. Archived from the original (PDF) on 2010-08- ... "Circadian rhythm abnormalities in totally blind people: incidence and clinical significance". J. Clin. Endocrinol. Metab. 75 (1 ... a condition in which a person's circadian rhythm, normally slightly longer than 24 hours, is not entrained (synchronized) to ...
Circadian rhythm sleep disorder *Advanced sleep phase disorder. *Delayed sleep phase disorder ...
... and therefore experience misalignment of their work schedule and their circadian rhythm. In 2007, 32% of healthcare workers ...
The team watched and recorded fly activity through the day and night to show that the fly restored circadian behavioral rhythms ... and Edery labs revealed that light causes the rapid degradation of TIM and resets of the phase of the circadian rhythm.[14][15] ... "Restoration of circadian behavioral rhythms by gene transfer in Drosophila". Nature. 312: 752-754. doi:10.1038/312752a0. PMID ... which makes proteins that are also necessary for circadian rhythm. He was awarded the 2017 Nobel Prize in Physiology or ...
Volicer L, Harper DG, Manning BC, Goldstein R, Satlin A. Sundowning and Circadian Rhythms in Alzheimer's Disease. The American ...
A study of circadian rhythms was concerned with the synchronization of primate motor activity, body temperature and skin ... temperature rhythms to a fixed light/dark cycle and to each other. Blood pressure and flow were monitored to evaluate short and ...
Circadian rhythm. disorders. *Advanced sleep phase disorder. *Delayed sleep phase disorder. *Irregular sleep-wake rhythm ...
Circadian rhythm sleep disorder *Advanced sleep phase disorder. *Delayed sleep phase disorder ...
Volicer L, Harper D, Manning B, Goldstein R, Satlin A (2001). "Sundowning and circadian rhythms in Alzheimer's disease". Am J ...
It has been observed that while serum or blood plasma concentrations follow a circadian rhythm or reflect short-term dietary ... This process follows a diurnal rhythm, so that enzyme expression peaks in the morning to support biosynthesis later on when mid ...
circadian rhythm. citric acid cycle. Also called the Krebs cycle and tricarboxylic acid cycle (TCA). ... as with endogenous cannabinoids and circadian rhythms. Contrast exogenous.. endoplasmic reticulum. A type of organelle found in ...
... circadian rhythms, emotional responses, learning, and memory. In other words, they address how these neural circuits function ...
circadian rhythm. • animal organ regeneration. • positive regulation of cell proliferation. • positive regulation of cell size ...
... a situational circadian rhythm sleep disorder. (Jet lag was previously included as a situational circadian rhythm sleep ... Sleep disorders are broadly classified into dyssomnias, parasomnias, circadian rhythm sleep disorders involving the timing of ... Special equipment may be required for treatment of several disorders such as obstructive apnea, the circadian rhythm disorders ... and disturbances of circadian rhythm.[10] *Insomnia: Insomnia may be primary or it may be comorbid with or secondary to another ...
Circadian rhythm is altered in null mice.[11] Fatal familial insomnia is thought to be the result of a point mutation in PRNP ... Cagampang FR, Whatley SA, Mitchell AL, Powell JF, Campbell IC, Coen CW (1999). "Circadian regulation of prion protein messenger ... RNA in the rat forebrain: a widespread and synchronous rhythm". Neuroscience. 91 (4): 1201-4. doi:10.1016/S0306-4522(99)00092-5 ... at codon 178, which corroborates PrP's involvement in sleep-wake cycles.[31] In addition, circadian regulation has been ...
Circadian rhythm sleep disorder *Advanced sleep phase disorder. *Delayed sleep phase disorder ...
Circadian rhythm. disorders. *Advanced sleep phase disorder. *Delayed sleep phase disorder. *Irregular sleep-wake rhythm ...
Circadian rhythm sleep disorder *Advanced sleep phase disorder. *Delayed sleep phase disorder ...
... with the rhythms of the circadian clock that allows plants to measure the length of the night. Other than flowering, ... Cryptochromes absorb blue light and UV-A. Cryptochromes entrain the circadian clock to light.[6] It has been found that both ...
ACTH is also related to the circadian rhythm in many organisms.[2] ... Dibner C, Schibler U, Albrecht U (2010). "The mammalian circadian timing system: organization and coordination of central and ...
... maintenance of normal circadian rhythms, and reduced risk of seasonal affective disorder.[43] ...
... has a circadian rhythm), with the lowest temperatures occurring at night, and the highest in the afternoons. Other normal ... Circadian variation in body temperature, ranging from about 7002310650000000000♠37.5 °C from 10 a.m. to 6 p.m., and falling to ...
2001). "Inversion of the circadian rhythm of melatonin in the Smith-Magenis syndrome". J Pediatr. 139 (1): 111-116. doi:10.1067 ... including several that are involved in controlling circadian rhythm, such as CLOCK.[8] The groups led by James Lupski (Baylor ... due to an inverted circadian rhythm of melatonin.[4]. People with Smith-Magenis syndrome have engaging personalities, but all ... De Leersnyder, H. (September 2006). "Inverted rhythm of melatonin secretion in Smith-Magenis syndrome: from symptoms to ...
"Circadian rhythms in human salivary flow rate and composition". Journal of Physiology. 220 (3): 529-545. PMC 1331668. PMID ...
Regulation of melatonin synthesis is important to melatonin's main function in circadian rhythms. The main molecular control ... important in the regulation of circadian rhythms. In humans, the suprachiasmatic nucleus of the hypothalamus communicates the ... this system of regulation maintains the body's circadian rhythms. Pinealocytes synthesize the hormone melatonin by first ...
Synchronous circadian voltage rhythms with asynchronous calcium rhythms in the suprachiasmatic nucleus Ryosuke Enoki, Yoshiaki ... Ultradian calcium rhythms in the paraventricular nucleus and subparaventricular zone in the hypothalamus Yu-Er Wu, Ryosuke ... Carbon monoxide protects the kidney through the central circadian clock and CD39 Matheus Correa-Costa, David Gallo, Eva ... Nuclear receptor HNF4A transrepresses CLOCK:BMAL1 and modulates tissue-specific circadian networks Meng Qu, Tomas Duffy, ...
Researchers have discovered that those with a disrupted circadian rhythm were unable to lose weight and keep it off no matter ... circadian rhythm of teams in the west traveling for a 10:00 am start, biggest win and loss from last season, odds to win ... circadian rhythms and mutation. The book closes with a fascinating look at the history and future trends for research on ... but rather of eating more frequently per day and irregular eating patterns which leads to a disrupted circadian rhythm. ...
Circadian Rhythms. Circadian rhythms are internally driven cycles of biochemical, physiological, and behavioral processes of ... throughout the human body that drive circadian rhythms. A master circadian pacemakera (sometimes called the circadian clock) in ... Circadian rhythms promote sleepiness before usual bedtime, help initiate sleep, and begin promoting wakefulness before usual ... As well as sleep and wakefulness, the pacemaker sets the timing for numerous circadian rhythms that regulate physiological and ...
Circadian Rhythms Promote Wakefulness. Figure 3 shows the rise and fall of circadian rhythms for wakefulness. ... The rise and fall of circadian rhythms, which promote wakefulness across the 24-hour day. ...
This is called the biological clock or circadian rhythm. The word... ... They all send timekeeping clues to the brain, helping keep circadian rhythms running according to schedule.. Circadian rhythms ... This type of rhythm exists in all living things. Humans have circadian rhythms. So do animals, insects, and even plants. They ... This is called the biological clock or circadian rhythm. The word circadian comes from the Latin words circa, meaning about, ...
Circadian Rhythms: Directed by Stewart Thorndike. With Jesse C. Boyd, Walker Satterwhite, Stephanie Drapeau, Davi Jay. The ...
Featured Content: Circadian Rhythms. Special Feature: The Daylighting Guide for Office Interiors. ... Read more about how lighting affects circadian rhythms like the sleep-wake cycle in our featured content otherwise available ... Repeating roughly every 24 hours, circadian rhythms have evolved under a natural regime of daylight days and dark nights. This ... It controls important biological processes and impacts circadian rhythms, including the sleep/wake cycle and other factors such ...
New research shows that a protein involved in circadian rhythms, called CLOCK, plays a role in severe cases of epilepsy that do ... CLOCK is a key player in the regulation of our circadian rhythms. Mice with mutated versions of the gene are unable to maintain ... a protein involved in circadian rhythms, called CLOCK, may play a role.. New findings may open the door to novel epilepsy ... there was a decrease in the expression of mRNA coding for a protein called circadian locomotor output cycles kaput (CLOCK). ...
This article looks at whether memory recall is affected by circadian rhythm. ... Circadian rhythm is the rhythm in which the cells function within a 24-hour cycle. ... What is circadian rhythm?. Circadian rhythm is the rhythm in which the cells of the body function within a 24-hour cycle. Each ... Recent research studied the memory recall and circadian rhythms in shift workers. The effects of exercise and circadian rhythms ...
Cellular Location and Circadian Rhythm of Expression of the Biological Clock Gene Period 1 in the Mouse Retina Paul Witkovsky, ... Loss of Photic Entrainment and Altered Free-Running Circadian Rhythms in math5−/− Mice Raymond Wee, Ana Maria Castrucci, ... Circadian Phase-Dependent Modulation of cGMP-Gated Channels of Cone Photoreceptors by Dopamine and D2 Agonist Gladys Y.-P. Ko, ... Identification of a Circadian Clock in the Inferior Colliculus and Its Dysregulation by Noise Exposure Jung-sub Park, ...
... those who are new to circadian biology, those who are already active in the field but are intereste ... The aim of Circadian Rhythms is to provide a resource that can be adopted by several types of users: ... The aim of Circadian Rhythms is to provide a resource that can be adopted by several types of users: those who are new to ... Use of Firefly Luciferase Activity Assays to Monitor Circadian Molecular Rhythms In Vivo and In Vitro ...
Abnormalities in circadian rhythm may identify patients in the very early stages of Parkinsons disease before symptoms develop ... Abnormalities in circadian rhythm may represent an important feature in the very early stages of Parkinsons disease before ... It would be useful to be able to identify these patients and maybe changes in circadian rhythms may help us to do that," she ... "If there is a causal link, then using techniques to improve circadian rhythm could help to prevent or slow the onset of ...
Provides a comprehensive review of the retinal circadian rhythmicity and photoreception A unique publication for a special ... The Retina and Circadian Rhythms. Editors: Tosini, G., Iuvone, P.M., McMahon, D.G., Collin, S.P. (Eds.) ... Moreover, accumulating evidence suggests that dysfunction of the circadian rhythms due to genetic mutations or environmental ... Daily rhythms are a ubiquitous feature of living systems. Generally, these rhythms are not just passive consequences of cyclic ...
Phase Coupling of a Circadian Neuropeptide With Rest/Activity Rhythms Detected Using a Membrane-Tethered Spider Toxin: ... Phase Coupling of a Circadian Neuropeptide With Rest/Activity Rhythms Detected Using a Membrane-Tethered Spider Toxin:. The ... we tested the hypothesis that phase of PDF secretion rhythms entrains phase of non-PDF neurons and locomotor rhythms using the ... Circadian Clock Neurons. Heres another interesting question from our most recent neurobiology exam. With some luck PZ wont ...
The crucial question is whether the microbes simply respond to their host humans circadian rhythm or whether they can actually ... Research suggests the composition and activity of microbiota has a circadian rhythm ... Gut and rhythm. The findings of the new study from Israel, which extends previous exciting work in this area, are relevant to ... Almost all life on Earth has an endogenous circadian rhythmicity that is genetically determined, but that also responds to ...
In clinical settings, an abnormal circadian rhythm in humans is known as a circadian rhythm sleep disorder. While there are ... Health problems can result from a disturbance to the circadian rhythm. Circadian rhythms also play a part in the reticular ... the circadian rhythm continues to be disrupted. The stabilization of sleep and the circadian rhythm might possibly help to ... circadian rhythms in quail. What drove circadian rhythms to evolve has been an enigmatic question. Previous hypotheses ...
Circadian rhythms are cyclical patterns in biological activities, such as sleeping, eating, body temperature and hormone ... Takahashi discovered in 1997, operates in many tissues of the body to regulate circadian rhythms. The gene codes for a protein ... Disruption of two genes that control circadian rhythms can lead to diabetes, a researcher at UT Southwestern Medical Center has ... Cells from different organs exhibited different circadian rhythm patterns, indicating that each organ controls its own internal ...
Purchase Hypothalamic Integration of Circadian Rhythms, Volume 111 - 1st Edition. Print Book & E-Book. ISBN 9780444824431, ... Hypothalamic Integration of Circadian Rhythms. 16. The anatomical basis for the expression of circadian rhythms: the efferent ... Entrainment of the Circadian Timing System. 7. Circadian rhythm generation, expression and entrainment in a molluscan model ... Hypothalamic Integration of Circadian Rhythms, Volume 111 1st Edition. Write a review ...
The clock acts on neural and endocrine pathways to regulate individual circadian rhythms so that internal state varies ... An early indication that the machinery is specified genetically came from studies of the circadian rhythms of cortisol ... Circadian clock molecules in flies. The expression of circadian timing in individual neurones shows that it is not an emergent ... Individual neurons dissociated from rat suprachiasmatic nucleus express independently phased circadian firing rhythms.Neuron ...
I read few days ago that central clock is also affected by food clock, circadian rhythm can be reset by fasting 16 hours prior ... For those who wake up early in the morning, eating breakfast and lunch and skipping dinner is best for circadian rhythm ... "It seems pretty clear that the long-term disruption of circadian rhythms is pretty harmful," Schibler added. ... Rotating shift workers are more likely to have dissynchronous body rhythms, increasing their likelihood of becoming diabetic, ...
A new study shows that older men who have a weak or irregular circadian rhythm guiding their daily cycles of rest and activity ... Their discovery of the link between circadian rhythms and Parkinsons suggests these circadian disruptions may reflect ... Disrupted Circadian Rhythm Linked to Later Parkinsons. By Traci Pedersen Associate News Editor ... A new study shows that older men who have a weak or irregular circadian rhythm guiding their daily cycles of rest and activity ...
Circadian Rhythms in Rapidly Dividing Cyanobacteria. By Takao Kondo, Tetsuya Mori, Nadya V. Lebedeva, Setsuyuki Aoki, Masahiro ... Circadian Rhythms in Rapidly Dividing Cyanobacteria. By Takao Kondo, Tetsuya Mori, Nadya V. Lebedeva, Setsuyuki Aoki, Masahiro ... Some messenger RNAs showed a circadian rhythm in abundance during continuous exponential growth with a doubling time of 5 to 6 ... Thus, the cyanobacterial circadian clock functions in cells that divide three or more times during one circadian cycle. ...
Circadian Rhythms RT2 Profiler PCR Array The Human Circadian Rhythms RT² Profiler PCR Array profiles the expression of 84 key ... Circadian Rhythms RT2 Profiler PCR Array The Mouse Circadian Rhythms RT² Profiler PCR Array profiles the expression of 84 key ... Circadian Rhythms RT2 Profiler PCR Array The Rat Circadian Rhythms RT² Profiler PCR Array profiles the expression of 84 key ... Although the circadian rhythm target genes vary widely from tissue to tissue, the transcription factors encoded by central ...
Circadian rhythm, the biological cycle for which the film is named "Circadian Rhythm". Circadian Rhythm at ... Circadian Rhythm is a 2005 action film that portrays a young womans journey to discover who she is and why multiple enemies ...
... circadian rhythm generation in mammals comes from transcriptional rhythms measured from primary and immortalized fibroblasts (3 ... or VIP-containing neurons exhibit intrinsic circadian rhythms in clock gene expression. We conclude that intrinsic circadian ... 2003) Disrupted circadian rhythms in VIP and PHI deficient mice. Am J Physiol Regul Integr Comp Physiol 285:R939-R949. ... Intrinsic, nondeterministic circadian rhythm generation in identified mammalian neurons. Alexis B. Webb, Nikhil Angelo, James E ...
... By Rick Nauert PhD Associate News Editor ... Nauert PhD, R. (2018). Circadian Rhythms of Gut Microbes Tied to Obesity. Psych Central. Retrieved on May 21, 2019, from https ... Investigators believe study results show that disruption of the circadian clock in the host alters the rhythms and composition ... But, until now, it has not been clear how changes in circadian rhythms increase the risk for these diseases. ...
Circadian Rhythm Could Discovery of Circadian Clocks in Bacteria Have Implications for Drug Delivery Timing, Industrial Biotech ... Circadian Rhythm Transcriptomics Reveals Liver Genes and Circadian Clock Crosstalk in Time and Space. ... Circadian Rhythm Linking Physiological Circuits to Circadian Block May Help Improve Human Health. ... Circadian Rhythm MicroRNAs Modulating Diurnal Rhythms in Cells Identified in Genome-Wide Study. ...
Circadian rhythms in teleost retinomotor movements: a comparison of the effects of circadian rhythms and light condition on ... Reebs S. (1992) Sleep, Inactivity and Circadian Rhythms in Fish. In: Ali M.A. (eds) Rhythms in Fishes. NATO ASI Series (Series ... Kavaliers, M., 1980a, Circadian locomotor activity rhythms of the burbot, Lota lota: Seasonal differences in period length and ... Reebs, S.G., and Colgan, P.W., 1991, Nocturnal care of eggs and circadian rhythms of fanning activity in two normally diurnal ...
This rhythm seems to be set by a biological clock which seems to be set by recurring daylight and darkness. ... Circadian Rhythm is the regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as ... Circadian rhythm plays a part in weight loss Weight watchers worldwide need to not only be careful about what to eat but also ... Circadian rhythms are 24 hour cycles that are guided by exposure to alternating periods of day and night. These cycles affect ...
measure sleep and circadian rhythms and the implications of poor sleep and/or circadian rhythms on performance and behaviour. ... The aim of the course is to provide knowledge in terms of central aspects of sleep and circadian rhythms and their role in ... How sleep and circadian rhythms are regulated and assessed - across species. *Normal development of and individual differences ... Plan and conduct simple experiments on sleep and circadian rhythms *Give an account of the most common sleep disorders, their ...
  • If confirmed to be a risk factor for Parkinson's disease, then circadian rhythmicity could be a promising intervention target and will open new opportunities for the prevention and management of Parkinson's disease," the researchers conclude. (
  • New research is beginning to show that the composition and activity of the microbiota exhibits a daily, or circadian, rhythmicity , just like we do. (
  • Almost all life on Earth has an endogenous circadian rhythmicity that is genetically determined, but that also responds to changes in light and dark . (
  • These findings on daily rhythmicity in microbiota have really piqued my interest because disruption of our circadian rhythmicity by electric light at night has been my research passion for several decades. (
  • Furthermore, neurons were observed to lose or gain circadian rhythmicity in these dispersed cell cultures, both spontaneously and in response to forskolin stimulation. (
  • Furthermore, SCN neurons isolated from their network either physically or by tetrodotoxin (TTX) can lose or gain rhythmicity, suggesting that SCN neurons are a heterogeneous population of intrinsic but unstable circadian oscillators. (
  • The students will be given insight on how sleep and circadian rhythmicity are measured subjectively and objectively. (
  • History: are prokaryotes capable of circadian rhythmicity? (
  • Thus, the work with various Synechococcus species firmly established that prokaryotic bacteria are capable of circadian rhythmicity, displacing the prior "no circadian clocks in prokaryotes" dogma. (
  • The adaptive fitness test was done by mixing cyanobacterial strains that express different circadian properties (i.e., rhythmicity vs. arhythmicity, different periods, etc.) and growing them in competition under different environmental conditions. (
  • As established, circadian rhythmicity has a profound effect on the physiological organization of vertebrates, so disruption of these rhythms has been associated with the development of multiple clinical conditions, such as mental and metabolic diseases, cancer, addiction and pain. (
  • This study assesses the feasibility of studying sleep and circadian rhythmicity in acutely ill, mechanically ventilated patients through the application of continuous bedside polysomnography. (
  • This study examines the feasibility of assessing sleep and circadian rhythmicity in critically ill patients undergoing mechanical ventilation. (
  • There's gap junctional communication between two cell types that accounts for the rhythmicity in one cell conferring rhythms on another cell," says Sehgal. (
  • Under constant conditions of light, sound, temperature, and humidity, rats exhibited circadian rhythmicity in rate of bar-pressing with hypothalamic and septal reinforcing brain stimulation. (
  • The rhythmicity of this process was also influenced by a known circadian clock gene in the mice, showing that the microbiome and the host both serve as the gut's timekeepers. (
  • Life evolved on Earth several billion years ago in a reliable cycle of light and dark, so that solar signal moulded an endogenous circadian rhythmicity in almost all life forms. (
  • To me it's little bit of a false distinction, because sleep is a very important aspect of circadian rhythmicity. (
  • Humans have circadian rhythms. (
  • Circadian systems are crucial to the working memory of all animals and humans. (
  • Researchers at the University of California, Irvine, discovered that a protein -- named CLOCK -- is an essential component in directing circadian rhythms in humans, fruit flies, mice, fungi and other organisms. (
  • In mammals, including humans, the master pacemaker controlling 24-hour rhythms is localized in the suprachiasmatic nuclei of the hypothalamus (SCN). (
  • 3 - 4 If these nuclei are destroyed, either experimentally in animals or as a result of disease in humans-for example, compression by expanding pituitary tumours-the ability to express any overt circadian rhythms is destroyed. (
  • In clinical settings, an abnormal circadian rhythm in humans is known as a circadian rhythm sleep disorder. (
  • The observation of a circadian or diurnal process in humans is mentioned in Chinese medical texts dated to around the 13th century, including the Noon and Midnight Manual and the Mnemonic Rhyme to Aid in the Selection of Acu-points According to the Diurnal Cycle, the Day of the Month and the Season of the Year. (
  • Finally, the circadian clock system, which controls the sleep-wake cycle and other diurnal oscillations in mice and humans, may also have a role in the neurodegenerative process. (
  • Circadian rhythms work in other animals in a similar way that they do in humans. (
  • However, the functional links between disturbances of the circadian rhythms and overall health in animal models and humans are yet to be characterized. (
  • In humans, a light pulse in the early evening delays rhythm-if it stays light later, you stay up later," says Sehgal. (
  • This story is focused on the science of circadian rhythms, the 24-hour physiological patterns that most organisms, including humans, follow each day. (
  • Chen and Yoo study circadian rhythms, the 24-hour physiological patterns that most organisms, including humans, follow each day. (
  • And she's at Neurotic Physiology, talking about an interesting study looking at ADHD and circadian rhythms in humans. (
  • This biological circadian system has evolved to help humans adapt to changes in our environment and anticipate changes in radiation, temperature, and food availability. (
  • Humans, like most animals and plants, have biological rhythms, known as circadian rhythms , which are controlled by a biological clock and work on a daily time scale. (
  • These experiments appeared to demonstrate that the "free-running" circadian rhythm in humans was about 25 hours long. (
  • It is also unclear whether some aspects of the vertebrate circadian clock, which has primarily been studied using nocturnal rodents, differ from those in diurnal vertebrates such as humans. (
  • Though it's far too early to extrapolate the data to more complex animals, recent studies have suggested a connection between humans circadian cycles and the function of microbes in the gut. (
  • In humans, that's controlled by a group of cells at the base of the brain called the suprachiasmatic nucleus (SCN), a gland that is the master circadian pacemaker. (
  • According to Amir, circadian rhythms allow organisms like flies, rats, monkeys, humans and even plants to anticipate and respond to the demands of their environment. (
  • Moreover, accumulating evidence suggests that dysfunction of the circadian rhythms due to genetic mutations or environmental factors (i.e., jet-lag or shift work) contribute to the development of many pathologies, including sleep disorders, mood and affective disorders such as major depression, bipolar disorder and schizophrenia, as well as the risk of metabolic and cardiovascular disorders. (
  • Sleeping disorders (such as apnea, insomnia, and desynchronosis) disrupt the timing of the circadian clock causing fatigue. (
  • Patients with disorders that affect the brain are more likely to have a circadian rhythm sleep disorder. (
  • How are circadian rhythm sleep disorders diagnosed? (
  • The researchers began with a discussion of melatonin's use for circadian rhythm and sleep disorders. (
  • These findings suggest that serotonin may play a role in maintaining circadian rhythm, as well as modulating light-related disorders such as seasonal affective disorder (SAD). (
  • By identifying the mechanism of interaction between serotonin and the body clock, as well as the environmental factors influencing the levels of serotonin in the brain, Sehgal and colleagues hope to be able to shed light on the possible role of circadian activity on affective disorders. (
  • The diagnosis of circadian rhythm disorders is primarily based on a thorough history. (
  • Dagan Y, Eisenstein M. Circadian rhythm sleep disorders: toward a more precise definition and diagnosis. (
  • Circadian rhythm sleep disorders: part I, basic principles, shift work and jet lag disorders. (
  • The translation of basic research findings to understand and treat sleep and circadian disorders is a key aim of the journal. (
  • The various chronic health conditions linked to irregular rhythms include diabetes, obesity, depression, bipolar disorder, seasonal affective disorder, and other sleep disorders. (
  • Further, clinical research has focused on the consequences of circadian disruption, circadian rhythm sleep disorders (CRSDs), circadian abnormalities in affective disorders, and chronotherapy. (
  • Circadian rhythm sleep disorders are a family of sleep disorders affecting, among other things, the timing of sleep. (
  • People with circadian rhythm sleep disorders are unable to sleep and wake at the times required for normal work, school, and social needs. (
  • Persistent circadian rhythm sleep disorders such as Non-24-hour sleep-wake syndrome are believed to be caused by an inadequate ability to reset the sleep/wake cycle in response to environmental time cues. (
  • Circadian rhythm sleep disorders: part II, advanced sleep phase disorder, delayed sleep phase disorder, free-running disorder, and irregular sleep-wake rhythm. (
  • To describe the physiologic and behavioral characteristics of circadian rhythm sleep disorders (CRSDs) following minor traumatic brain injury (mTBI) in patients complaining of insomnia. (
  • b>Circadian rhythm sleep disorders are common conditions manifested as misalignment between the sleep period and the physical/social 24-h environmental cycle. (
  • These results demonstrate a benefit of performing drug screens using intact animals and provide novel targets for treating circadian rhythm disorders. (
  • Dr. Alon Avidan of UCLA's Sleep Disorders Center calls the result "circadian rhythm disorder. (
  • In addition, most other sleep disorders can damage circadian rhythms and further compound sleep problems. (
  • The National Institute of Health estimates that over 35 million Americans suffer from circadian rhythm disorders. (
  • All organisms exposed to sunlight possess a diurnal biological clock that controls a circadian rhythm of gene expression changes in most cell types. (
  • These cycles affect biological activities in a variety of living organisms which are attuned to the circadian clock. (
  • Organisms on this planet, including human beings, exhibit a biological rhythm that repeats about every 24 h to adapt to the daily environmental alteration caused by the rotation of the earth. (
  • [1] The conclusion that only eukaryotes have circadian oscillators seemed reasonable, because it was assumed that an endogenous timekeeper with a period close to 24 hours would not be useful to prokaryotic organisms that often divide more rapidly than once every 24 hours. (
  • Do circadian timekeepers enhance the fitness of organisms growing under natural conditions? (
  • Despite the expectation that circadian clocks are usually assumed to enhance the fitness of organisms by improving their ability to adapt to daily cycles in environmental factors, there have been few rigorous tests of that proposition in any organism. (
  • Previous explanations of the prokaryotic circadian timekeeper were dependent upon a DNA transcription / translation feedback mechanism, and, although this has not been shown to be the case, it is still believed to hold true for eukaryotic organisms. (
  • In addition, the authors examine circadian rhythms in other species (e.g., plants and Drosophila ) and how they enable the organisms to adapt to their environments. (
  • Most of the lecture will be spent on describing daily or circadian rhythms in organisms from bacteria to man. (
  • Circadian rhythms are biological oscillations with a period of about 24 hours, which allow the organisms to anticipate changes in the environment. (
  • Biological clocks are the internal mechanisms controlling circadian rhythms in various organisms. (
  • Most organisms have endogenous circadian clocks that coordinate physiological and behavioral rhythms and synchronize the organism to daily environmental cycles. (
  • Circadian clocks are endogenous and temperature-compensating timekeepers that provide temporal organization of biological processes in living organisms. (
  • Circadian rhythms allow living organisms to adapt to the daily light cycles associated with Earth's rotation and to anticipate and prepare for precise and regular environmental changes. (
  • This book discusses the fundamental advances of how the circadian clock regulates critical biological functions as well as the cellular and molecular mechanisms controlling circadian rhythm in living organisms. (
  • RICHARD STEVENS: Circadian biology has been considered a bit of a quaint sideline that didn't matter very much, but that began to change about 30 years ago, and it's now clear that circadian biology is fundamental to all biology, to almost all organisms on the planet. (
  • Mice with mutated versions of the gene are unable to maintain normal daily rhythms of sleep and wakefulness. (
  • Daily rhythms are a ubiquitous feature of living systems. (
  • The mammalian suprachiasmatic nucleus (SCN) of the anterior hypothalamus coordinates daily rhythms including sleep-wake and hormone release ( 5 ). (
  • Subsequent in vivo ( 13 ) and in vitro ( 8 , 14 ) results continue to support the idea that neurons from the dorsal and ventral SCN maintain daily rhythms. (
  • The study showed that hydrogen peroxide given to fruit flies has dramatic effects on their daily rhythms and activity levels. (
  • In 1985-86, several research groups discovered that cyanobacteria display daily rhythms of nitrogen fixation in both light/dark (LD) cycles and in constant light. (
  • When people living in many parts of the world move their clocks forward one hour in the spring in observance of daylight saving time (DST), their bodies' internal, daily rhythms don't adjust with them, reports a new study appearing online on October 25th in Current Biology, a publication of Cell Press. (
  • The hypothalamus, which we have identified as a brain region that is particularly susceptible to developmental disruption by BPA, contains the site of the clock cells that govern daily rhythms throughout the body," said researcher Deborah Kurrasch, Ph.D., Associate Professor at the University of Calgary in Calgary, Canada. (
  • We will discuss the elaborate molecular mechanisms that allow circadian clocks to produce their daily rhythms and to synchronise them to its environment. (
  • The suprachiasmatic nucleus (SCN) of the hypothalamus contains about 15,000 neurons in mammals, and is the source of a light-independent 24-hour rhythm which serves as a central clock governing daily rhythms throughout the rest of the body. (
  • physiological and homeostatic functions that follow these kinds of daily rhythms. (
  • The regulation of the daily fluctuations that characterize an organism's physiology and behavior requires coordination of the cellular oscillations of individual "clock" neurons within the circadian control network. (
  • Clock neurons that secrete a neuropeptide called pigment dispersing factor (PDF) calibrate, or entrain, both the phase of organismal rhythms and the cellular oscillations of other clock neurons. (
  • Circadian rhythms are modeled as reliable and self-sustained oscillations generated by single cells. (
  • Oscillations in these processes, or circadian rhythms, are controlled by molecular feedback loops that integrate with environmental and metabolic stimuli. (
  • Links between circadian and redox systems, as well as the relationship between circadian oscillations and pathogenic infections, are also covered. (
  • Thus, multiple signals, including a diffusible factor(s) from the SCN, are sufficient to either entrain or restart circadian oscillations in cortical glia. (
  • 1 Since that time, basic research has explored various aspects, including the intracellular generation of circadian oscillations, their intercellular synchronisation, the entrainment of the circadian "system" by environmental time cues or "zeitgebers" such as light, and circadian variation in biological functioning. (
  • Molecular circadian oscillations in cells in different tissues and brain regions cycle with distinct phases, suggesting that non-cell autonomous mechanisms transmit circadian information throughout an animal 1 . (
  • These biological oscillations are apparent as diurnal rhythms. (
  • If it did, "the cooperation between microbiota and circadian oscillations in intestinal metabolism would have increased the energy intake from food in our ancestors," Faraz Bishehsari and Ali Keshavarzian of Rush University Medical Center write in an accompanying commentary . (
  • CLOCK is a key player in the regulation of our circadian rhythms. (
  • The basis of circadian rhythm regulation was noticed in the fly strain, seeing the first clock gene in an animal. (
  • 9. Regulation of entrainment pathways by the suprachiasmatic circadian clock: sensitivities to second messengers (M.U. Gillette). (
  • 13. Regulation and integration in the mammalian circadian system (M.R. Ralph et al. (
  • Analyzing the expression, regulation, and sequence of circadian rhythm genes can provide a better understanding of the regulation of the biological clock in all tissues and how its disruption affects normal processes and contributes to disease. (
  • QIAGEN provides a broad range of assay technologies for circadian rhythm research that enables analysis of gene expression and regulation, epigenetic modification, genotyping, and signal transduction pathway activation. (
  • Washington, Nov 8 (ANI): Scientists from University of Southern California have identified a chemical that appears to play a vital role in regulation of body's circadian rhythm. (
  • Zisapel N. New perspectives on the role of melatonin in human sleep, circadian rhythms and their regulation. (
  • With increasing age, the circadian system undergoes significant changes that affect rhythms of behaviors, temperature regulation, and hormone release, to name only a few examples. (
  • We'll discuss examples of these processes and ideas about how this circadian regulation works. (
  • The interplay of serotonin, light, and the circadian system suggests a close relationship between circadian regulation and mental health. (
  • One of the most compelling features of per and tim regulation is that the mRNAs cycle with a peak a few hours in advance of the rhythm in their protein products in the fly's head ( H all 2003 ). (
  • Reiter, R.J., Tan, D.X., Sanchez-Barcelo, E. and Mediavilla, M.D. (2011) Circadian Mechanism in the Regulation of Melatonin Synthesis: Disruption with Light at Night and the Pathophysiological Consequences. (
  • It focuses on the mechanisms of sleep/wake and circadian regulation at the molecular and systems level and. (
  • It focuses on the mechanisms of sleep/wake and circadian regulation at the molecular and systems level and on research to examine the function of sleep. (
  • The regulation of sleep is processed by the homeostatic physiology of the circadian rhythm, the sleep/wake cycle. (
  • The presence of circadian rhythms in cells with and without nuclei indicate that the molecular clock is autonomous and external cues can be utilized for regulation. (
  • However, few studies have focused on the underlying circadian regulation of the hypothalamus-pituitary-thyroid (HPT) axis, and the mechanisms to explain it," Dr. Dibner continued. (
  • There are numerous peripheral circadian oscillators (clocks) throughout the human body that drive circadian rhythms. (
  • In order for scientists to identify endogenous circadian rhythms a subject must be isolated from sunlight, clocks, environmental sounds, and to all other cues of time . (
  • BETHESDA, Md., March 10 (UPI) -- Resetting the human biological clock -- circadian rhythm -- is a lot harder than resetting a wristwatch or clocks, a U.S. researchers said. (
  • Cells from different organs exhibited different circadian rhythm patterns, indicating that each organ controls its own internal clocks. (
  • Despite predictions that circadian clocks would not be expressed by cells that are doubling faster than once per 24 hours, [8] the cyanobacterial rhythms continue in cultures that are growing with doubling times as rapid as one division every 5-6 hours. (
  • Given that prolonged disruptions of normal rhythms are highly detrimental to health, deeper knowledge of how our biological clocks change with age may create valuable opportunities to improve health and longevity for an aging global population. (
  • This volume will therefore serve as a valuable reference for not only neurobiologists and cell and molecular biologists, but all who wish to understand the clocks and rhythms of life. (
  • Circadian clocks serve to orchestrate physiology and metabolism in a coordinated way over the course of the day. (
  • These biological clocks regulate circadian rhythms and their resulting behaviors and bodily changes, such as sleep, hormone function and body temperature. (
  • Researchers knew that human cells have molecular clocks that time 24-hour circadian cycles of metabolism ( SN: 11/8/18 ), and that gut microbes in the colon follow their hosts' biological beat ( SN: 10/16/14 ). (
  • Among people with healthy circadian clocks, there is a continuum of chronotypes from "larks" or "morning people" who prefer to sleep and wake early, to "owls" who prefer to sleep and wake at late times. (
  • 1. Light, photoreceptors and circadian clocks Russell G. Foster, Mark W. Hankins and Stuart N. Peirson 2. (
  • Glad to see that there is more and more research confirming that this and many other ills are associated with impaired circadian bio-clocks. (
  • Red blood cells, similar to other cells in the body, have 24 hour biological clocks (circadian rhythms) that alter their activity between day and night. (
  • Just as we have internal clocks that help regulate the systems in our bodies, fruit and vegetable plants have circadian rhythms, too. (
  • Circadian clocks are cell-autonomous. (
  • Using an experimental approach for the study of human peripheral clocks, she described how they assessed the properties of the circadian oscillator in human primary thyrocytes that were obtained from biopsies of benign or malignant human tissue. (
  • While diagnostic application of the altered circadian clock findings is still a few years away, the ongoing research about circadian clocks and thyroid function has immediate application for the practicing endocrinologist," commented Joel Ehrenkranz, MD, medical director of diabetes and endocrinology at Intermountain Medical Center in Murray, Utah, who moderated the session. (
  • I've been studying circadian clocks -- internal biological clocks -- and how they affect human health and disease for about 30 years. (
  • What we didn't know until recently is that not only can saturated fat actually cause 'jet lag' in the internal circadian clocks in some types of cells in the body, but this effect is accompanied by strong inflammation. (
  • We found that palmitate resets circadian clocks in some cells, but not all. (
  • In fact, everything you can measure in an organism follows a daily rhythm - a 24-hour cycle generated by internal clocks present in each and every cell in our bodies. (
  • While Amir's initial research interest was in circadian rhythm, over the last 10 years, he has expanded his focus to other clocks in the brain - those that control different types of behaviours and pathological conditions, such as depression, anxiety, drug addiction and diseases like Parkinson's. (
  • How Drosophila circadian pacemaker drives organismal rhythms? (
  • Therefore, voltage-gated Na+ channels of Drosophila clock neurons play a key role in determining the phase relationship between circadian transcriptional feedback oscillation and PDF secretion, and PDF-secreting clock neurons entrain the phase of organismal rhythms via the temporal patterning of secreted PDF signals. (
  • I will confess to not being an expert in the field of Drosophila circadian pacemakers, nor am I a neurophysiologist, but I commend these authors on their use of a remarkably novel technique. (
  • 3. The Drosophila genes timeless and period collaborate to promote cycles of gene expression composing a circadian pacemaker (M.W. Young). (
  • An early indication that the machinery is specified genetically came from studies of the circadian rhythms of cortisol secretion in twins, but as in so many other biomedical fields, the real impetus to molecular genetic analysis of the clock 83 has come from fruit flies (Drosophila spp). (
  • In 1954, an important experiment reported by Colin Pittendrigh demonstrated that eclosion (the process of pupa turning into adult) in Drosophila pseudoobscura was a circadian behaviour. (
  • They went on to discover the key genes and neurones in Drosophila circadian system, for which Hall, Rosbash and Young received the Nobel Prize in Physiology or Medicine 2017. (
  • The circadian mechanism appears remarkably conserved between Drosophila and mammals, with basic underlying negative and positive feedback loops, cycling gene products, and temporally regulated nuclear transport involving a few key proteins. (
  • Genetic and biochemical experiments over the past decade have allowed the construction of a viable working model for the molecular mechanisms underlying circadian rhythm generation in Drosophila . (
  • Light cycles can synchronize the Drosophila circadian pathway by directly stimulating Cryptochrome-dependent degradation of Timeless. (
  • This Pathway Map of the Drosophila circadian mechanism describes the individual known components of the fly circadian clock and their mutual interactions. (
  • To understand this, we screened for signals that could identify circadian output circuits in Drosophila melanogaster. (
  • Disruption of two genes that control circadian rhythms can lead to diabetes, a researcher at UT Southwestern Medical Center has found in an animal study. (
  • Normal islet cells glowed in a 24-hour rhythm, while cells with defective CLOCK genes showed nearly flat rhythms. (
  • The circadian rhythm of gene activity changes with age, according to new study at the University of Pittsburgh School of Medicine that examined thousands of genes from nearly 150 human brains. (
  • As we expected, younger people had that daily rhythm in all the classic 'clock' genes," Dr. McClung said. (
  • But there was a loss of rhythm in many of these genes in older people, which might explain some of the alterations that occur in sleep, cognition and mood in later life. (
  • In future research, the scientists plan to explore the function of the brain's circadian-rhythm genes in lab and animal models, as well as see if they are altered in people who have psychiatric or neurological illnesses. (
  • By analysing the circadian patterns of activity and emergence from the pupal case of mutant flies, several genes have been identified that encode essential elements of the clock. (
  • Interacting positive and negative feedback loops at the transcriptional and post-translational level ensure tight control over transcription factors regulating expression of the appropriate genes required during circadian days or nights. (
  • Although the circadian rhythm target genes vary widely from tissue to tissue, the transcription factors encoded by central clock and clock-controlled genes are mostly shared across all cell types. (
  • Genes regulated by circadian rhythms are involved in a diverse range of biological processes that affect physiology, metabolism, and behavior. (
  • The Human Circadian Rhythms RT² Profiler PCR Array profiles the expression of 84 key genes defining and regulating the biological clock. (
  • Role Identified for Brain Protein Regulated by Circadian Clock Genes in. (
  • Dr. Panda's research focuses on the genes and cells that serve as the building blocks of the circadian rhythm. (
  • We investigated whether glia, like neurons, rhythmically express circadian genes. (
  • In perfect "clockwork" fashion, these genes continuously work together to release proteins that synchronize our biological rhythms with the time of day. (
  • Some studies on the relationship between breast cancer and sleep disturbances from shift work point to hypermethylation of certain circadian genes and the shortening of telomeres-both associated risk factors for cancer. (
  • Unlike other cells, red blood cells do not have DNA and the 'clock genes' that control rhythms are not present. (
  • The circadian rhythms in all of the knockout strains of upf1-3 genes, which encode the Up-frameshift proteins, were aberrant. (
  • We also demonstrated that the clock genes including White Collar (WC)-1, WC-2, and FRQ are involved in controlling the diurnal growth rhythm, and UPF1 may affect the growth rhythms by mediating the FRQ protein levels in the daytime. (
  • Dr. Shimon Amir researches circadian rhythms and clock genes. (
  • Amir was born and raised in Israel and moved to Montreal for his PhD. He went back to Israel to work at the Weizmann Institute of Science, but later returned to Montreal to teach and do research on circadian rhythms and now, too, clock genes. (
  • Circadian rhythms are internally driven cycles of biochemical, physiological, and behavioral processes of living beings that rise and fall across the 24-hour day. (
  • This circadian clock is responsible for the temporal organization of a wide variety of functions, ranging from sleep and food intake, to physiological measures such as body temperature, heart rate and hormone release. (
  • Further research should look at whether physiological changes set off by disruptions in circadian rhythms might themselves be a trigger for neurodegeneration, and whether strengthening these rhythms could lower the risk for developing Parkinson's, say the researchers. (
  • The body's circadian clock system maintains these 24-h rhythms in physiological functions, including the sleep-wake cycle, and synchronizes them to the light-dark cycle. (
  • In this Review, we synthesize key findings from the study of circadian rhythms in later life, identify patterns of change documented to date, and review potential physiological mechanisms that may underlie these changes. (
  • Circadian rhythms are the cyclical hormonal and physiological processes that rally the body in the morning to tackle the day's demands and slow it down at night, allowing the body to rest and repair. (
  • Anything that affects the intensity of light or the wavelength can have important consequences for the synchronization of the circadian rhythm, and that can have effects on all types of physiological processes," Dr. Berson said. (
  • A circadian rhythm is a roughly-24-hour cycle in the physiological processes of living beings, including plants, animals, fungi and cyanobacteria . (
  • Physiological rhythms of patients with AD and FTD were then compared with a group of normal, elderly men (n = 8) from the community. (
  • The body's 24-hour (circadian) clock controls cycles of wakefulness and sleep, as well as the rhythm of other physiological functions, such as body temperature and blood pressure. (
  • As we'll discuss later, being good to our natural rhythms improves daily physiological and psychological function-and ultimately short- and long-term health. (
  • Synchronized by light and darkness, the circadian clock exerts control over wake/sleep cycles, body temperature, digestion, hormonal cycles and other physiological and behavior patterns. (
  • The establishment of the 24-hour circadian rhythms occurs during the first 4 months of life as the newborn experiences rapid physiological changes and adapts to the environment. (
  • As infants experience rapid physiological changes just after birth, deviations in core body temperature, as well as the production of melatonin and cortisol allow an infant to establish a stable circadian rhythm. (
  • The circadian clock ensures that behavioral and physiological processes occur at appropriate times during the 24-hour day/night cycle, and is regulated at both the cellular and organismal levels. (
  • Circadian rhythms help ensure that physiological processes and behaviors occur at appropriate times during the 24-hour day/night cycle. (
  • Circadian rhythms are daily observations in behavioural, physiological and metabolic processes," explained Dr. Shimon Amir, professor of psychology, Concordia University in Montreal, and director of the university's Centre for Studies in Behavioural Neurobiology. (
  • A master circadian pacemaker a (sometimes called the circadian clock) in the hypothalamus of the brain (see Figure 2.4) synchronizes and controls the timing of these peripheral circadian oscillators so they work together. (
  • The pacemaker has an internally driven 24-hour rhythm that tends to run longer than 24 hours but is reset every day by external timing cues to keep the cycle at 24 hours. (
  • Recent studies have implicated dysfunction of the circadian pacemaker in the etiology of these disturbances in dementia. (
  • These changes in sleep timing are associated with an earlier timing of multiple endogenous rhythms, including core body temperature (CBT) and plasma melatonin, driven by the circadian pacemaker. (
  • One possible cause of the age-related shift of endogenous circadian rhythms and the timing of sleep relative to clock time is a change in the phase-shifting capacity of the circadian pacemaker in response to the environmental light-dark cycle, the principal synchronizer of the human circadian system. (
  • Light stimuli were scheduled 1.5 or 3.5 hours after the CBT nadir to induce shifts of endogenous circadian pacemaker to an earlier hour (phase advances) or were scheduled 1.5 hours before the CBT nadir to induce shifts to a later hour (phase delays). (
  • it is not known whether glia act as circadian pacemakers, modulate neural pacemaking, or are targets of SCN pacemaker neurons. (
  • Twenty-four hour rhythms in behavior are organized by a network of circadian pacemaker neurons. (
  • We also found pacemaker neuron-dependent activity rhythms in a second circadian output pathway controlled by DH44 neuropeptide-expressing neurons. (
  • While the suprachiasmatic nucleus (SCN) acts as a central circadian pacemaker to regulate circadian rhythms in mammals, it is unclear how the SCN transmits circadian information and if additional non-cell autonomous mechanisms exist. (
  • This raises awareness of the importance of circadian rhythm in older individuals and changes in their 24-hour pattern of behavior could be an early signal of Parkinson's disease," she said. (
  • Young mice lacking the BMAL1 gene only in their pancreas, however, had normal body weight and composition, and their behavior followed normal circadian patterns, although their blood sugar levels were abnormally high, the researchers found. (
  • Genetic deletion of these repressors abolishes circadian rhythms in behavior and physiology ( 2 ). (
  • Circadian rhythms play an influential role in nearly all aspects of physiology and behavior in the vast majority of species on Earth. (
  • In this Review, we survey some of the key age-associated changes in circadian rhythms of behavior, physiology, and molecular processes. (
  • For example, the behavior of wearing sunglasses would not be classified as a circadian rhythm - if there were no sunlight, the behavior would not persist. (
  • But whether the circadian clock regulated aggressive behavior was unknown. (
  • To determine whether such diurnal changes are caused by an endogenous circadian rhythm or by diurnal alterations in behavior or the environment, we measured indices of pulmonary function throughout a "constant routine" protocol designed to unmask underlying circadian rhythms. (
  • They had no specific target molecule in mind, but one clear winner emerged: there was a decrease in the expression of mRNA coding for a protein called circadian locomotor output cycles kaput (CLOCK). (
  • GABA releases in time with the circadian rhythms controlling sleeping and waking cycles. (
  • A new study shows that older men who have a weak or irregular circadian rhythm guiding their daily cycles of rest and activity are more likely to develop Parkinson's disease, a condition characterized by loss of control over movement, balance and other brain functions. (
  • 1 - 2 As with all biological processes, the clock driving these cycles is slightly imperfect, therefore the measurable rhythms free run with periods of slightly less than or greater than one solar day, hence circadian (approximately a day). (
  • Although circadian rhythms are endogenous, they are adjusted to the local environment by external cues called zeitgebers (German for "time givers"), which include light, temperature and redox cycles. (
  • Circadian rhythms are 24 hour cycles that are guided by exposure to alternating periods of day and night. (
  • When most people hear the term 'circadian rhythm,' they think about sleep cycles. (
  • Chronic circadian changes can be seen with advanced sleep-phase syndrome (ASPS), delayed sleep-phase syndrome (DSPS), and irregular sleep-wake cycles. (
  • Glial rhythms entrained to daily 1.5°C temperature cycles and were significantly sustained when cocultured with explants of the adult SCN but not with cortical explants. (
  • Circadian rhythm is the 24-hour internal clock in our brain that regulates cycles of alertness and sleepiness by responding to light changes in our environment. (
  • These rhythms are generated and sustained at the cellular level by a transcriptional-translational negative-feedback loop that cycles with a period of approximately 24 hours, and are entrained by environmental cues such as light, food availability and temperature 1 . (
  • Circadian rhythms are the 24-hour cycles of physical and mental changes that are driven by your body's "biological clock. (
  • Redox Cycling of Intracellular Thiols: State Variables for Ultradian, Cell Division Cycle and Circadian Cycles? (
  • Researchers had also shown that the microbiome was important for this rhythm, as wiping it out also wipes out the intestines' daily cycles. (
  • Glowing bacteria that live in the light-generating organs of the tiny bobtail squid play a key role in determining the animal's circadian rhythms - the natural cycles that help determine when a creature sleeps, wakes, and eats - according to a study published this week in the journal mBio . (
  • reference source: This area of your brain regulates the firing of nerve cells that seem to set your circadian rhythms. (
  • 6. Circadian rhythms of neuropeptides in the suprachiasmatic nucleus (S.-I.T. Inouye). (
  • 16. The anatomical basis for the expression of circadian rhythms: the efferent projections of the suprachiasmatic nucleus (R.M. Buijs). (
  • In experimental animals with such ablation, central grafting of neonatal hypothalamic tissue containing the suprachiasmatic nuclei can restore circadian patterning to the activity-rest cycle. (
  • Also, when neonatal suprachiasmatic nucleic tissue is dissociated and held in vitro, the individual neurones show robust circadian rhythms of electrical firing, each of them with a slightly different period from its neighbours as they free run in the culture dish. (
  • In mammals, for example, stimulation of the hypothalamic suprachiasmatic nucleus (SCN) in the brain by light mediates hormonal signaling to control the circadian rhythm in peripheral tissues. (
  • In mammals, the suprachiasmatic nucleus (SCN) is the master circadian clock. (
  • Contributors discuss the cell-autonomous generation of circadian time and how those mechanisms interact with circuit-level mechanisms in the suprachiasmatic nucleus. (
  • The specific part of the hypothalamus that is involved in the circadian rhythm is known as the suprachiasmatic nucleus, which regulates our internal clock when we are exposed to light and darkness. (
  • Liu, C., Weaver, D.R. and Reppert, S.M. (1997) Cellular Construction of a Circadian Clock: Period Determination in the Suprachiasmatic Nuclei. (
  • The mammalian CLOCK gene, which Dr. Takahashi discovered in 1997, operates in many tissues of the body to regulate circadian rhythms. (
  • The clock acts on neural and endocrine pathways to regulate individual circadian rhythms so that internal state varies predictably over 24 hours. (
  • As the eyes age, less and less sunlight gets through the lens to reach key cells in the retina that regulate the body's circadian rhythm, its internal clock. (
  • Next, the scientists used genetics-based tools to manipulate neurons known to regulate the central circadian clock. (
  • The circadian rhythm uses positive and negative molecular feedback loops as a mechanism to regulate their expression. (
  • Thus, despite extensive research, mechanisms that regulate circadian rhythms remain incompletely understood. (
  • Thus, alternative approaches could reveal novel mechanisms that regulate the circadian clock. (
  • The authors cover the physiology of diurnal rhythm thoroughly and discuss melatonin's emerging roles in diseases of aging. (
  • Aging affects all aspects of our physiology and behaviors, including the circadian clock. (
  • A circadian rhythm is a 24-hour period affecting the physiology of all living creatures, including plants and animals. (
  • Without this endogenous circadian clock, Homo sapiens would not be able to optimize energy expenditure and the internal physiology of the body. (
  • Examining the relationship between circadian rhythms in the human body and its cellular biology is essential to understand the underlying physiology and pathology in diseases. (
  • The purpose of this study is to assess both the sleep and circadian (24-hourly biological rhythms) physiology of people with cluster headache. (
  • Rhythmic activity in this network is generated by intrinsic rhythms in clock neuron physiology and communication between clock neurons. (
  • That was the takeaway presented by Charna Dibner, PhD, research group leader in the Laboratory of Circadian Endocrinology at Geneva University Hospitals and the University of Geneva, during a plenary lecture, Thyroid Circadian Timing: Roles in Physiology and Thyroid Malignancies, on September 22, 2016 at the American Thyroid Association 86th annual meeting in Denver, Colorado. (
  • Thyroid Circadian Timing: Roles in Physiology and Thyroid Malignancy at the American Thyroid Association 86th Annual Meeting, September 22, 2016, Denver, Colorado. (
  • MARGO WHITE: This year the Nobel Prize in physiology or medicine was awarded to three researchers for their discoveries of molecular mechanisms controlling the circadian rhythm. (
  • The strongest evidence for cell-autonomous, circadian rhythm generation in mammals comes from transcriptional rhythms measured from primary and immortalized fibroblasts ( 3 , 4 ). (
  • The SCN of the anterior hypothalamus is the master clock controlling circadian rhythms in mammals. (
  • lesions of the SCN abolish activity rhythms in mammals. (
  • The development of the circadian system occurs in mammals postnatally. (
  • This book is an authoritative collection of essays that will appeal to scientists who have a background in molecular biology and who would like to read conveniently brief summaries (about 20 pages each, including references) of research advances in the study of circadian rhythms. (
  • The study of circadian rhythms in red blood cells can potentially help us understand when and why heart attacks mostly occur during the morning. (
  • It would be useful to be able to identify these patients and maybe changes in circadian rhythms may help us to do that," she added. (
  • NEW ORLEANS--Exposure to the widely used chemical bisphenol A (BPA) during pregnancy, even at levels lower than the regulated "safe" human exposure level, can lead to changes in circadian rhythms, according to a mice study to be presented Monday at ENDO 2019, the Endocrine Society's annual meeting in New Orleans, La. The researchers report these changes may be a contributing factor in hyperactivity seen in BPA-exposed mice. (
  • Now we have shown that abnormalities in the overall 24-hour circadian rest activity rhythm are also present in the prodromal phase of Parkinson's, and this association was independent of several confounders, including nighttime sleep disturbances," Leng commented. (
  • Disturbances in the sleep-wake cycle and circadian rhythms are common symptoms of Alzheimer Disease (AD), and they have generally been considered as late consequences of the neurodegenerative processes. (
  • Disturbances of both sleep and the underlying circadian rhythms have long been associated with many neurological and psychiatric diseases, including Alzheimer Disease (AD). (
  • Although these sleep and circadian abnormalities were once dismissed as consequences of the disease process, accumulating evidence suggests that sleep and circadian disturbances likely occur very early in the disease process and may contribute to the pathogenesis of AD. (
  • Differential circadian rhythm disturbances in men with alzheimer disease and frontotemporal degeneration. (
  • CONCLUSIONS: Patients with AD and patients with FTD show different disturbances in their rhythms of activity and temperature compared with each other and with normal elderly patients. (
  • Circadian Rhythm Disturbances (CRDs) affect as many as a quarter of Alzheimer's disease (AD) patients during some stage of their illness. (
  • Circadian Rhythm Disturbances (CRDs) in AD often present dramatically and are among the major triggers for institutionalization [ 5 , 6 ]. (
  • This is an important part of the history in patients with circadian rhythm disturbances. (
  • It is not routinely used in the diagnostic evaluation of patients with insomnia or in the diagnostic evaluation of patients with circadian rhythm disturbances. (
  • The evidence is insufficient to recommend the routine use of the Morningness Eveningness Questionnaire (MEQ) for the evaluation of circadian rhythm disturbances. (
  • There are over 100 bodily functions and behaviors that follow circadian rhythms. (
  • If they don't follow circadian rhythms, they'll die. (
  • A healthy circadian rhythm is what helps us feel awake during the day while allowing us to sleep deeply and peacefully at the night. (
  • Maintaining consistent and healthy circadian rhythms may help improve overall health and prevent chronic diseases. (
  • In a healthy circadian cycle, melatonin is released by the pineal gland in the brain when it starts to get dark. (
  • Instead, these results indicate that AVP, VIP, and other SCN neurons are intrinsic but unstable circadian oscillators that rely on network interactions to stabilize their otherwise noisy cycling. (
  • Taken together, these results suggest that single SCN neurons are competent circadian oscillators. (
  • Because AVP and VIP release can have different circadian periods in the same organotypic SCN slice, it was hypothesized that these 2 groups of neurons are separate oscillators ( 12 ). (
  • We investigated whether astroglia are competent circadian oscillators able to respond to diffusible signals from the SCN. (
  • There is a body-wide web of circadian oscillators," Dr. Dibner said. (
  • Is the Subject Area "Circadian oscillators" applicable to this article? (
  • The prize was awarded jointly to three scientists for discovering the mechanisms controlling circadian rhythm. (
  • Circadian rhythms promote sleepiness before usual bedtime, help initiate sleep, and begin promoting wakefulness before usual wake-up time in the morning. (
  • Figure 3 shows the rise and fall of circadian rhythms for wakefulness. (
  • The rise and fall of circadian rhythms, which promote wakefulness across the 24-hour day. (
  • They also discussed delayed sleep phase syndrome and advanced sleep phase syndrome, conditions in which circadian rhythm of sleep and wakefulness is out of sync. (
  • Our circadian rhythm is geared towards wakefulness in the day and sleepiness in the night. (
  • An irregular sleep-wake schedule features multiple sleep episodes without evidence of recognizable ultradian or circadian features of sleep and wakefulness. (
  • Scientific research has found that increased weight gain is largely a result not of the number of calories consumed per meal, but rather of eating more frequently per day and irregular eating patterns which leads to a disrupted circadian rhythm. (
  • This issue is compounded during winter months when days are shorter and a majority of time is spent inside, leaving room for circadian disruption and impacts on sleep patterns and mood. (
  • Patterns of rest and activity were measured with an actigraph device, which is worn on the wrist like a watch and captures movements which are translated into a rest-activity rhythm model - one of the most commonly used and evidence-based measures of circadian rhythm," Leng said. (
  • Researchers at the National Institute of General Medical Sciences, part of the National Institute of Health, said circadian rhythms determine sleep patterns and contribute to jet lag as well as any grogginess after a time change. (
  • Circadian rhythms are cyclical patterns in biological activities, such as sleeping, eating, body temperature and hormone production. (
  • BPA-exposed mice exhibited alterations in their daily patterns and timing of activity, indicating disrupted circadian signaling. (
  • This includes migration patterns, which are driven by a circadian rhythm. (
  • The biological clockwork that regulates these rhythms is dynamic over the lifespan: rhythmic activities such as sleep/wake patterns change markedly as we age, and in many cases they become increasingly fragmented. (
  • The first endogenous circadian oscillation was observed in the 1700s by the French scientist Jean-Jacques d'Ortous de Mairan who noticed that 24-hour patterns in the movement of the leaves of the plant Mimosa pudica continued even when the plants were isolated from external stimuli. (
  • Implicit in the diagnosis of circadian rhythm disorder is a desire to conform to traditionally accepted sleep-wake patterns. (
  • The study will include measurement of basic rest-activity patterns, sleep timing and timing of individual attacks, as well as a more detailed study recording sleep and circadian rhythms under clinical conditions over consecutive nights. (
  • Recent advances in research have discovered that circadian rhythm is endogenously generated and can be modulated externally by cues such as the weather. (
  • Typically, the people with this disorder have brains that don't recognize the lighting cues that signal circadian rhythms. (
  • The sleep-wake cycle is the most obvious example of a circadian process, as it occurs with a consistent 24-h rhythm and can be shifted according to environmental cues. (
  • In a strict sense, circadian rhythms are endogenously generated, although they can be modulated by external cues, primarily daylight. (
  • The rationale for this criterion is to distinguish circadian rhythms from those "apparent" rhythms that merely respond to external periodic cues. (
  • The rationale for this criterion is to distinguish circadian rhythms from other imaginable endogenous 24-hour rhythms that are immune to resetting by external cues and hence do not serve the purpose of estimating the local time. (
  • It results from an inability to synchronize one's normal rhythm to rapidly changing time shifts of environmental cues. (
  • and SCN neurons show sustained circadian gene expression, electrical activity, and neuropeptide secretion in the absence of external cues. (
  • Time cues keep the normal human circadian clock aligned with the rest of the world. (
  • When deprived of exogenous time cues, many of these diurnal rhythms persist, indicating their generation by an endogenous biological circadian clock. (
  • Studies suggest individuals can control their body clock and lead the tempo of circadian rhythms controlling daily behaviors dependent on events throughout the 24-hour cycle. (
  • Hydrogen peroxide is a great candidate for a signaling molecule that would be involved in rhythms and behaviors. (
  • A disruption of this rhythm may be considered a circadian rhythm sleep disorder. (
  • What are the symptoms of a circadian rhythm sleep disorder? (
  • A circadian rhythm sleep disorder can impact many facets of your life. (
  • There are several types of circadian rhythm sleep disorder. (
  • Disruptions of one or more of these factors can lead to a circadian rhythm sleep disorder. (
  • Who is at risk for a circadian rhythm sleep disorder? (
  • Certain medical conditions can make a person more likely to experience a circadian rhythm sleep disorder. (
  • People who travel overseas often are more likely to have a circadian rhythm sleep disorder. (
  • A sleep medicine specialist can diagnose a circadian rhythm sleep disorder. (
  • Circadian rhythm sleep disorder is a persistent rhythm disruption sleep disorder that is characterized by an altered sleep cycle.Circadian rhythm is a term used to describe the body clock that manages the sleep and wake cycle of a human being. (
  • Circadian rhythm sleep disorder is also called sleep wake schedule disorder, or dyssomnia. (
  • These are the major symptoms of circadian rhythm sleep disorder, characterized by habitual late sleep and an inability to stick to a general sleep schedule. (
  • The same gene was identified to be defective in a sleep disorder called FASPS (Familial Advanced Sleep Phase Syndrome) in human beings thirty years later - underscoring the conserved nature of the molecular circadian clock through evolution. (
  • Jet lag disorder occurs when air travel puts us in different time zones in a short amount of time, which throws off the circadian rhythm because we don't have enough time to adjust. (
  • Non-24-hour sleep-wake disorder results from a circadian rhythm that's running for more than 24 hours at a time. (
  • Now, a study conducted by Ben Bullock and Greg Murray of the Swinburne University of Technology and published in Clinical Psychological Science reveals that one factor - instability in circadian rhythm - is one particularly strong predictor of vulnerability for bipolar disorder. (
  • Reduced Amplitude of the 24-hr Activity Rhythm: A Biomarker of Vulnerability to Bipolar Disorder? (
  • When our circadian rhythm is disrupted, it can cause a brain disorder that manifests in a series of detrimental conditions too numerous to list, but that includes insomnia, depression and Parkinson's disease. (
  • Their discovery of the link between circadian rhythms and Parkinson's suggests these circadian disruptions may reflect neurodegenerative disease processes already affecting the brain's internal clock well before a Parkinson's diagnosis, and that they could be considered an early warning sign of the disease. (
  • Disruptions of circadian rhythms were exaggerated in the 24-hour dark cycle. (
  • Circadian rhythms play a vital role in health, and prolonged disruptions to the clock are associated with negative health consequences. (
  • Maybe one day there will also be more research into how a lack of awareness of the passage of one's local circadian and circalunar time can contribute to such disruptions, per what we are doing as described at (
  • diurnal rhythms should not be called circadian rhythms unless they can be confirmed as endogenous, and not environmental. (
  • While there are multiple mentions of "natural body cycle" in Eastern and Native American cultures, the earliest recorded Western accounts of a circadian process date from the 4th century BC, when Androsthenes, a ship's captain serving under Alexander the Great, described diurnal leaf movements of the tamarind tree. (
  • The earliest known account of a circadian rhythm dates from the fourth century BC, when Androsthenes, in descriptions of the marches of Alexander the Great, described diurnal leaf movements of the tamarind tree. (
  • Numerous studies have demonstrated a diurnal rhythm in indices of pulmonary function in both healthy subjects and subjects with asthma, with minima occurring during the night. (
  • Thus, endogenous circadian rhythms contribute to diurnal changes in pulmonary function in healthy subjects. (
  • The first writings, at least in the western canon, to recognize diurnal rhythms come from the fourth century BC. (
  • These findings suggest that the NMD factors play important roles in regulating the circadian clock and diurnal growth rhythms in Neurospora . (
  • Researchers have discovered that those with a disrupted circadian rhythm were unable to lose weight and keep it off no matter what they tried. (
  • Researchers probing the brain tissue of people with severe forms of epilepsy make a surprising breakthrough: a protein involved in circadian rhythms, called CLOCK, may play a role. (
  • Circadian rhythms can understand molecules and cells that provide a network into memory and allow researchers to develop lifestyles and seasonal changes in memory. (
  • For the study, the researchers analyzed data from 2930 community-dwelling men aged 65 years or older (mean age, 76 years) who participated in the Osteoporotic Fractures in Men Study in which they underwent comprehensive sleep and rest-activity rhythms assessment. (
  • Future studies are needed to explore underlying mechanisms and to determine whether circadian disruption itself might contribute to the development of Parkinson's disease, the researchers say. (
  • The mice also were engineered to contain a bioluminescent molecule that allowed the researchers to detect the circadian clock in pancreatic cells as a fluctuating glow. (
  • Researchers in Switzerland have conducted a review of studies looking at how circadian rhythm affects the immune response and severity of illnesses ranging from heart attack to allergy. (
  • Circadian rhythm has been studied by countless researchers and professors for years, but Dr. Satchidananda Panda, of the Salk Institute in San Diego, California, is a leader in the field -he has conducted some of the most innovative and insightful research on the subject. (
  • The researchers studied melanoma in mice using the glucocorticoid dexamethasone (DEX) to increase the functionality of the circadian clock. (
  • This is an in-depth examination of circadian biology, presented by leading researchers in the field. (
  • This book provokes interest in many readers, researchers and scientists, who can find this information useful for the advancement of their research works towards a better understanding of circadian rhythm regulatory mechanisms. (
  • Researchers observed a significant variation in potassium content in the cells which corresponded with the circadian rhythm - increased levels during the day followed by a decrease at night. (
  • By changing the amount of potassium the cell receives, the researchers were able to increase and decrease its levels in the cell and observe the effects on their circadian rhythms. (
  • The researchers found that higher levels of potassium negatively impacted the circadian rhythm of the cell, whilst lower levels were observed as extending the duration of the cell's perceived "day" by several hours. (
  • Circadian rhythms can boost the body's ability to fight intestinal bacterial infections, University of California, Irvine, researchers have found. (
  • Researchers and clinicians have found that the timing of medical treatments-including vaccines and chemotherapy for brain cancer-can influence their efficacy, but it is still unclear how the circadian clock exerts these effects. (
  • When the researchers injected flies lacking the period gene, which encodes an essential element of the circadian clock, they observed no difference in the levels of dye in the flies' brains over the course of the day, suggesting that permeability depends on the molecular clock. (
  • Researchers led by Margaret J. McFall-Ngai at the University of Wisconsin found that the circadian rhythms of the bobtail squid were not governed solely by light in the environment, as was commonly thought, but depended on the presence of the microbe Vibrio fischeri, a strain of light-generating bacteria that makes it's home in the squid's organs and acts as a kind of secondary lamp for the cephalopod. (
  • In this study, we tested the hypothesis that phase of PDF secretion rhythms entrains phase of non-PDF neurons and locomotor rhythms using the tethered- toxin technique (which affixes toxins to the cell membrane) to express ion channel-specific peptide toxins in PDF neurons. (
  • Inhibition of Na+ channel inactivation in PDF neurons of transgenic flies induces phase advance of PDF rhythm, and correlated phase advance of lights-on anticipatory locomotor activity, suggesting that phase of morning activity is determined by phase of PDF oscillation. (
  • We tested the hypothesis that circadian cycling is intrinsic to a unique class of SCN neurons by measuring firing rate or Period2 gene expression in single neurons. (
  • We found that fully isolated SCN neurons can sustain circadian cycling for at least 1 week. (
  • 100 cells/mm 2 eliminated synaptic inputs and revealed circadian neurons that contained arginine vasopressin (AVP) or vasoactive intestinal polypeptide (VIP) or neither. (
  • In SCN explants treated with tetrodotoxin to block spike-dependent signaling, neurons gained or lost circadian cycling over many days. (
  • Multielectrode array (MEA) recordings of neuronal firing and luciferase-based reporters of Per1 and Per2 expression showed dissociated SCN neurons in the same culture with different circadian periods ( 6 , 7 ). (
  • Several classes of neurons within the SCN have been proposed to be intrinsically circadian ( 10 ). (
  • We sought to identify intrinsically circadian neurons within the SCN as AVP- or VIP-ergic. (
  • Here we demonstrate circadian rhythms in gene expression and firing rate from isolated SCN neurons and their subsequent identification by immunocytochemistry. (
  • However, not all AVP or VIP SCN neurons are circadian. (
  • The circadian influences of SCN neurons are distributed through different target organs by efferent neural and humoral signals particularly circulating melatonin. (
  • Furthermore, immunocytochemical (ICC) localization using enzymatic staining procedures reveals that PER is not localized to the nucleus of any neurons within the brain at any circadian time, as recently observed for several nondipteran insects. (
  • Now, for the first time, a team of neuroscientists at Beth Israel Deaconess Medical Center (BIDMC) has demonstrated circadian control of aggression in male mice and identified the specific neurons and circuitry regulating the daily pattern. (
  • Entrainment of the Circadian Timing System. (
  • 7. Circadian rhythm generation, expression and entrainment in a molluscan model system (G.D. Block et al. (
  • 8. Entrainment pathways and the functional organization of the circadian system (R.Y. Moore). (
  • 11. Entrainment of the circadian clock (M.H. Hastings et al. (
  • Synchronization, or "entrainment", of the circadian clock. (
  • Joseph Takahashi discovered the first mammalian circadian clock mutation (clockΔ19) using mice in 1994. (
  • Overall, we conclude that low-dose gestational BPA exposure alters circadian rhythms under various conditions, and that this may be a contributing factor to the observed hyperactivity in BPA-exposed mice. (
  • Bacteria in the small intestine of mice may set the clock on the animals' metabolic rhythms. (
  • Mice (and maybe people) may metabolize food according to daily, circadian rhythms set by gut bacteria. (
  • Those "germ-free mice" also lacked strong circadian rhythms in cells lining the rodents' small intestines, microbiologist Lora Hooper of the University of Texas Southwestern Medical Center in Dallas and colleagues found. (
  • Giving the mice intestinal bacteria, however, strengthened those circadian rhythms. (
  • Counting the intensity and frequency of residents' attacks on intruders revealed for the first time that aggression in male mice exhibits a daily rhythm. (
  • The steps in mechanistic research are illustrated using research on circadian rhythms. (
  • RF-1 was exhibiting circadian rhythms, and in a series of publications beginning in 1986 demonstrated all three of the salient characteristics of circadian rhythms described above in the same organism, the unicellular freshwater Synechococcus sp. (
  • Recent research studied the memory recall and circadian rhythms in shift workers. (
  • Rotating shift workers are more likely to have dissynchronous body rhythms, increasing their likelihood of becoming diabetic, obese or depressed, Yang said. (
  • We have shown in previous research that BPA exposure in utero can cause defects to the development of hypothalamic nuclei and hyperactivity, and here we explored whether a shift in circadian biology might explain why the animals moved more. (
  • This internal clock relies on light to function properly, and studies have found that people whose circadian rhythms are out of sync, like shift workers, are at greater risk for a number of ailments, including insomnia, heart disease and cancer . (
  • If the findings carry over to people, the research may give clues to why jet lag and night-shift work, which can throw off circadian rhythms, often lead to obesity, diabetes and other health problems. (
  • the memory is stored in the mammalian hippocampus, the memory center, and is most likely to be the area in which the circadian rhythms occur. (
  • 5. Astrocytes in the mammalian circadian clock: putative roles (J. Servière, M. Lavialle). (
  • Several drugs identified in the screen did not affect circadian rhythms in cultured cells derived from luminescent reporter embryos or in established zebrafish and mammalian cell lines, suggesting they act via mechanisms absent in cell culture. (
  • Our finding that the intestinal microbiota programs the daily rhythmic expression of small intestine metabolic networks illuminates an essential role for the microbiota in regulating host metabolism and indicates that the microbiome, the circadian clock, and the mammalian metabolic system have tightly coevolved," the authors write in their report. (
  • Circadian rhythms also influence body temperature to a degree. (
  • Body temperature is lowest when a person is inactive and higher during physical activity, but circadian rhythm can raise or lower temperature independent of physical activity. (
  • We know also that the circadian rhythm changes with aging, leading to awakening earlier in the morning, fewer hours of sleep and less robust body temperature rhythms. (
  • He demonstrated that while temperature played a vital role in eclosion rhythm, the period of eclosion was delayed but not stopped when temperature was decreased. (
  • The rhythm has the same period over a range of temperatures (i.e., it is temperature-compensated). (
  • The circadian system is essentially the biological clock of the body in charge of maintaining the daily rhythm of various bodily processes, such as body temperature, appetite, and sleep. (
  • METHODS: We studied the activity and core-body temperature rhythms in a cohort of 38 male patients with a clinical diagnosis of probable Alzheimer disease (AD) approximately 2 years before death. (
  • RESULTS: Alzheimer patients showed increased nocturnal activity and a significant phase-delay in their rhythms of core-body temperature and activity compared with patients with FTD and controls. (
  • The activity rhythm of FTD patients was highly fragmented and phase-advanced in comparison with controls and apparently uncoupled from the rhythm of core-body temperature. (
  • Since core body temperature is one of the most tightly regulated systems, deviations, among other things, reveal the establishment of circadian rhythm. (
  • A second defining attribute of circadian rhythms is that they are endogenously generated and self-sustaining, so they persist under constant environmental conditions, typically constant light (or dark) and constant temperature. (
  • Your circadian rhythms affect your sleep-wake cycle, your body temperature, and other important body functions. (
  • These 24-hour rhythms are driven by a circadian clock, and they have been widely observed in plants, animals, fungi, and cyanobacteria. (
  • 15. Perinatal development of human circadian rhythms (M. Mirmiran, S. Lunshof). (
  • Marked 24-h rest/activity rhythms are associated with better quality of life, better response, and longer survival in patients with metastatic colorectal cancer and good performance status," Clinical Cancer Research , vol. 6, no. 8, pp. 3038-3045, 2000. (
  • These new findings may help to inform the development of new therapeutic interventions for at-risk populations - strengthening and stabilizing activity rhythms may be one way to protect against bipolar, for instance. (
  • However, over the last 30 or so years, the powerful approaches of molecular genetics have revealed the molecular underpinnings of a cellular circadian clockwork as complicated and as beautiful as the wonderful chronometers developed in the 18th century. (
  • In her lab, Dr. Dibner's team looked at whether circadian clockwork changed when thyroid malignancies were present. (
  • Section I. Molecular and Cellular Mechanisms of Circadian Pacemakers. (
  • Circadian pacemakers are schematized as intracellular transcription-translation negative feedback loops ( 1 ). (
  • Typical indoor environments do not have the necessary lighting levels, spectrum, and timing to stimulate the circadian system. (
  • In a study published in The British Journal of Ophthalmology, Dr. Mainster and Dr. Turner estimated that by age 45, the photoreceptors of the average adult receive just 50 percent of the light needed to fully stimulate the circadian system . (
  • The literature contains a large variety of associations of these areas with melatonin and circadian rhythm. (
  • Rhythms in gene expression in the brain are highly disrupted in people with schizophrenia, according to a new University of Pittsburgh-led study. (
  • A cellular, rather than soluble, substrate of the circadian effect of BCG vaccination was demonstrated by the enhanced capacity to induce trained immunity in vitro in morning- compared with evening-isolated monocytes.CONCLUSIONS BCG vaccination in the morning induces stronger trained immunity and adaptive responses compared with evening vaccination. (
  • A growing number of studies suggest a strong link between the cellular circadian cycle, damage to DNA, programmed cell death and the development of cancer," 1,2 she said. (
  • 5 The circadian mechanism is therefore autonomous in cells, and the clock is so powerful that the rhythms of a single neurone can be recorded continuously for several weeks with only the slightest deviation from 24hours. (
  • The circadian clock is the master mechanism, or timer, to make sure that everything runs smoothly and according to plan. (
  • The gradual yellowing of the lens and the narrowing of the pupil that occur with age disturb the body's circadian rhythm, contributing to a range of health problems, these studies suggest. (
  • This study was designed to test the hypotheses that a delayed weekend sleep pattern may lead to a phase delay of the endogenous circadian rhythm, and that melatonin administration can counteract the phase delay and prevent the sleep and functional impairments associated with this sleep pattern. (
  • CONCLUSION: A delayed weekend sleep pattern did show a mild phase-delay effect on the endogenous circadian rhythm. (
  • Continued disruption of the circadian clock is a source of bodily stress and a risk factor for cancer and cardiovascular disease. (
  • The disruption of the circadian rhythm can have severe health implications for multiple organ systems including the immune, reproductive, gastrointestinal, skeletal, endocrine, renal, and cardiovascular systems. (
  • This controls the circadian rhythms. (
  • His work is particularly focused on a portion of the brain known as the hypothalamus, which controls the circadian rhythm and utilizes several hormones to affect different parts of the body. (
  • Specifically, our main objective is to provide a major input to the understanding of the molecular mechanisms and the impact of gene-environment interactions of circadian rhythms on certain medical pathologies. (