• Animal cells and systems
• /
• v.16 no.1
• /
• pp.1-10
• /
• 2012

Most living organisms synchronize their physiological and behavioral activities with the daily changes in the environment using intrinsic time-keeping systems called circadian clocks. In mammals, the key molecular features of the internal clock are transcription- and translational-based negative feedback loops, in which clock-specific transcription factors activate the periodic expression of their own repressors, thereby generating the circadian rhythms. CLOCK and BMAL1, the basic helix-loop-helix (bHLH)/PAS transcription factors, constitute the positive limb of the molecular clock oscillator. Recent investigations have shown that various levels of posttranslational regulation work in concert with CLOCK/BMAL1 in mediating circadian and cellular stimuli to control and reset the circadian rhythmicity. Here we review how the CLOCK and BMAL1 activities are regulated by intracellular distribution, posttranslational modification, and the recruitment of various epigenetic regulators in response to circadian and cellular signaling pathways.

• Biomolecules & Therapeutics
• /
• v.26 no.4
• /
• pp.358-367
• /
• 2018

Most organisms have adapted to a circadian rhythm that follows a roughly 24-hour cycle, which is modulated by both internal (clock-related genes) and external (environment) factors. In such organisms, the central nervous system (CNS) is influenced by the circadian rhythm of individual cells. Furthermore, the period circadian clock 2 (Per2) gene is an important component of the circadian clock, which modulates the circadian rhythm. Per2 is mainly expressed in the suprachiasmatic nucleus (SCN) of the hypothalamus as well as other brain areas, including the midbrain and forebrain. This indicates that Per2 may affect various neurobiological activities such as sleeping, depression, and addiction. In this review, we focus on the neurobiological functions of Per2, which could help to better understand its roles in the CNS.

• Safety and Health at Work
• /
• v.8 no.3
• /
• pp.276-281
• /
• 2017

Background: The present study was carried out to assess the relationship between sickness absence and occupational stress, sleep quality, and amplitude and stability of circadian rhythm as well as to determine contributing factors of sickness absence. Methods: This cross sectional study was conducted on 400 randomly selected employees of an Iranian gas company. The data were collected using Pittsburgh sleep quality index, Karolinska sleepiness scale, circadian type inventory, and Osipow occupational stress questionnaires. Results: The mean age and job tenure of the participants were $33.18{\pm}5.64years$ and $6.06{\pm}4.99years$, respectively. Also, the participants had been absent from work on average 2.16 days a year. According to the results, 209 participants had no absences, 129 participants had short-term absences, and 62 participants had long-term absences. The results showed a significant relationship between short-term absenteeism and amplitude of circadian rhythm [odds ratio (OR) = 6.13], sleep quality (OR = 14.46), sleepiness (OR = 2.08), role boundary (OR = 6.45), and responsibility (OR = 5.23). Long-term absenteeism was also significantly associated with amplitude of circadian rhythm (OR = 2.42), sleep quality (OR = 21.56), sleepiness (OR = 6.44), role overload (OR = 4.84), role boundary (OR = 4.27), and responsibility (OR = 3.72). Conclusion: The results revealed that poor sleep quality, amplitude of circadian rhythm, and occupational stress were the contributing factors for sickness absence in the study population.

• Journal of Oral Medicine and Pain
• /
• v.40 no.3
• /
• pp.89-95
• /
• 2015

All living organisms have a biological clock that orchestrates every biological process and function, and this internal clock operates following a circadian rhythm. This biological clock is known to influence various clinical indicators such as blood pressure and body temperature. Also, the fluctuation of signs and symptoms of diseases including pain disorders are affected by circadian rhythm. It has been reported that the pain intensity of various somatic and neuropathic pain disorders show unique pain patterns that depend on the passage of time. The generation of pain patterns could be explained by extrinsic (e.g., physical activity, tactile stimulation, ambient temperature) and also intrinsic factors (neural and neuroendocrine modulation) that are related to the circadian rhythm. It is important to recognize and identify the individual pain pattern in pain therapy to approve treatment outcome. Moreover, chronotherapeutics which considers pain patterns and pharmacokinetics in context of the circadian rhythm could produce greater analgesia in response to medication. However, only a limited number of studies handle the issue of pain patterns according to circadian rhythm and chronotherapeutics in the orofacial region. The present review intends to reflect on the most recent and relevant data concerning the bidirectional relation between pain disorders of the orofacial region and circadian patterns.

• Molecules and Cells
• /
• v.42 no.4
• /
• pp.301-312
• /
• 2019

Post-transcriptional regulation underlies the circadian control of gene expression and animal behaviors. However, the role of mRNA surveillance via the nonsense-mediated mRNA decay (NMD) pathway in circadian rhythms remains elusive. Here, we report that Drosophila NMD pathway acts in a subset of circadian pacemaker neurons to maintain robust 24 h rhythms of free-running locomotor activity. RNA interference-mediated depletion of key NMD factors in timeless-expressing clock cells decreased the amplitude of circadian locomotor behaviors. Transgenic manipulation of the NMD pathway in clock neurons expressing a neuropeptide PIGMENT-DISPERSING FACTOR (PDF) was sufficient to dampen or lengthen free-running locomotor rhythms. Confocal imaging of a transgenic NMD reporter revealed that arrhythmic Clock mutants exhibited stronger NMD activity in PDF-expressing neurons than wild-type. We further found that hypomorphic mutations in Suppressor with morphogenetic effect on genitalia 5 (Smg5) or Smg6 impaired circadian behaviors. These NMD mutants normally developed PDF-expressing clock neurons and displayed daily oscillations in the transcript levels of core clock genes. By contrast, the loss of Smg5 or Smg6 function affected the relative transcript levels of cAMP response element-binding protein B (CrebB) in an isoform-specific manner. Moreover, the overexpression of a transcriptional repressor form of CrebB rescued free-running locomotor rhythms in Smg5-depleted flies. These data demonstrate that CrebB is a rate-limiting substrate of the genetic NMD pathway important for the behavioral output of circadian clocks in Drosophila.

• Journal of Korean Academy of Nursing
• /
• v.40 no.1
• /
• pp.43-51
• /
• 2010

Purpose: The purpose of this study was to investigate sleep habits, sleep disturbance, and circadian types, and to identify factors influencing sleep disturbance in nursing students. Methods: Participants were 140 senior nursing students. The data were collected from May 19 to 27, 2008 using self-report questionnaires. Results: 1) Evening type delayed sleep-wake schedules were more frequent than for morning type, especially during weekend and evening shift duty. 2) In total sleep time, there were no significant statistical differences between morning type and evening type during weekdays, weekend, day or evening shift duty. 3) On weekdays and day shift duty, the mean score for sleep disturbance was significantly higher in the evening type compared to the morning type. 4) Sleep disturbance in weekday and day shift duty was influenced by circadian types, eating habits, and gender. Conclusion: The circadian types are a very important factor for determining the sleep quantity and quality in nursing students.

• Journal of Korean Biological Nursing Science
• /
• v.1 no.1
• /
• pp.86-99
• /
• 1999

The purpose of this study is to find out the difference in circadian rhythm and level of fatigue between ER and General Ward Nurse. This study was done through analyzing body temperature, heart rate and major electrolytes such as $Na^+$ and $K^+$ concentration on urinalysis, which are related to factors of circadian rhythm and level of fatigue. The subjects, 17 nurses from Emergency Room and 25 nurses from general ward, were selected from a General Hospital in Taegu City on August 8 to 23, 1998. And the data were analyzed by proportion, t-test, chi-square and Pearson's Correlation, ANCOVA, using SAS program. The results of this study were shown as follows: First, The difference of Maximal and minimal heart rate was significant between ER group and general ward group. However, body temperature difference wasn't notable. Second, Urine $Na^+$ concentration on urinalysis was lower and $K^+$ concentration on urinalysis was higher in ER group than general ward group significantly. Third, Fatigue level was higher in ER group than general ward group significantly. Fourth, through urine concentration, significant relations in circadian rhythm of ER nurse group and general ward group and their fatigue level were found. Urine $Na^+$ concentration on urinalysis of ER nurse was significant related with their fatigue level. In conclusion, the effect of fatigue on circadian rhythm is greater in ER group than general ward group during night shift. This study could be a help in improvement of nurse's health and understanding the effect of fatigue on health.

• Journal of Korean Biological Nursing Science
• /
• v.19 no.1
• /
• pp.48-54
• /
• 2017

Purpose: This study was done to identify the influence of severity of drinking problem, circadian rhythm and sleep quality in patients with alcohol use. Methods: A descriptive study design was utilized. Data were collected using self-report questionnaires from 139 patients with alcohol use disorder who were admitted to a psychiatric hospital in D city, Korea. The questionnaires included Alcohol Use Disorders Identification Test (AUDIT), Composite Scale of Morningness (CMS), Pittsburgh Sleep Quality Index (PSQI), and Korea sleep scale A. Data were analyzed using descriptive statistics, Pearson's correlation coefficients, and multiple regressions using the SPSS 20.0 program. Results: There was significant correlations among severity of problem drinking, circadian rhythm, sleep quality and sleep disorder. The significant factors influencing sleep disorder were severity of problem drinking(${\beta}=.12$, p= .042), circadian rhythm(${\beta}=-.14$, p= .039) and sleep quality(${\beta}=.63$, p= < .001). This model explained 56% of variance in sleep disorder(F = 57.34, p= < .001). Conclusion: The results of this study suggest that the development of sleep intervention programs for alcohol use disorder patients needs to consider severity of alcohol use, circadian rhythm and sleep quality, and sleep assessment and intervention are needed the early stage of the treatment and recovery process.

• Journal of Korean Academy of Nursing
• /
• v.24 no.2
• /
• pp.175-189
• /
• 1994

This study examined the daily rhythmic patterns of mood in shift workers. Ten rotating shift nurses (shift worker group) were matched with ten non-rotating student nurses (non - shift worker group) working under the same conditions at University Hospital. The subjects completed the Mood Adjective Checkist (MAC) every two or three hours from 6AM to 9-11 PM for six consecutive days. The MAC was constructed by Mansour and conversed the mood factors of Anger - Depression. Happiness, Mental, and Social. These data were analyzed by using Cosinor method. The results are summarized as follows : 1. There was no difference in mean scores for Anger - Depression, Happiness, Mental, and Social mood rhythm between the shift workers and the non - shift workers. 2. There was no difference in the amplitude of Anger - Depression, Happiness and Social mood between the two groups, but the shift workers had a higher amplitude of Mental mood. 3. The acrophases of the Anger - Depression mood were between 1:28 and 2:05, and those of Happiness, Social, and Mental mood were between 12:5 and 15:03 for both groups. There were no differences between the groups. 4. The number of the subjects with statistically significant mean cosinor rhythms for Anger-De-pression and Mental moods were higher in the shift workers than in the non-shift workers, but there were no differences between the shift workers and the non-shift workers in those of Happiness and Mental mood. This study showed that the mod manifested circadian periodicities, and a rapidly rotating shift system did not changed the circadian rhythm of mood. It is expected that this study will facilitate a better understanding of circadian rhythm in mood in the shiftworkers.

• Childhood Kidney Diseases
• /
• v.16 no.1
• /
• pp.1-8
• /
• 2012

Nocturnal polyuria is one of the main pathogenic mechanisms of enuresis. Disturbance of circadian rhythm of antidiuretic hormone (ADH or AVP), hypercalciuria, and/or solute diuresis are considered to cause nocturnal polyuria, which in turn causes enuresis in patients with relatively small bladder capacity and high threshold for awakening. Evaluation of these factors would guide the therapeutic approach for enuresis.