Circadian Variation Research Articles

AF in the AFternoon: The circadian pattern of incident atrial fibrillation in a loop recorder population

Abstract Introduction Loop recorders have provided the opportunity to systematically screen individuals for arrhythmias, and in doing so provide new appreciated mechanistic insights to arrhythmia pathophysiology. Atrial fibrillation (AF) is a complex arrhythmia with a multitude of precipitants and substrates. Previous studies looking at the circadian rhythm of AF, have required patient symptoms to define onset. All studies on the circadian rhythm of AF suggest that AF does not occur randomly. It has been suggested that the circadian variation in autonomic function may provide an underlying substrate for AF initiation. This is the largest study to utilise loop recorder detected AF to explore the circadian pattern of AF. Purpose We sought to ascertain how the detection of incident AF varied throughout the day, in patients monitored with a loop recorder Methods This was a single-centre retrospective observational study. Consecutive adult patients referred for ILR implantation between March 2009 and November 2019, without prevalent AF or atrial flutter, were included. Demographic and anthropometric data was identified from the individuals medical notes. The time of incident AF episodes was identified from loop recorder reports. Results A total of 1168 AF episodes of any duration were identified by the ILR, of which onset time was available for 1118 episodes. Onset of AF episodes in our data for the entire population demonstrated a monophasic distribution (figure 1a). The OR for developing AF between 13.00-14.59 compared to 03.00-04.59 was 4.89 (95% CI 3.47-6.90). Amongst the ESUS population time of onset distribution showed multiple daytime peaks (figure 1b). The OR for developing AF between 10.00-11.59 compared to 03.00-04.59 was 4.39 (95% CI 2.68-7.20). Amongst the non- ESUS population time of onset distribution (figure 1c) shows a monophasic pattern with the peak at time blocks 12.00-14.59. The OR for developing AF between 13.00-14.59 compared to 02.00-03.59 was 6.75 (95% CI 4.17-10.93). Conclusion(s) Our study demonstrated that there is a diurnal variation for incident AF detection using a loop recorder. There is a general propensity for episodes to occur in the afternoon, with a nadir at night. This is in contrast to previous reports which have suggested that the nocturnal and morning peaks are more apparent. Moreover, different cohorts appear to show different temporal patterns, with ESUS patients having multiple time peaks, whereas the non-stroke cohort had a solitary peak period. Understanding the diurnal variation of AF may help to shed more light on the complex pathogenesis of AF, and whether different AF phenotypes are associated with stroke risk. Moreover, the finding of a day-time propensity for AF, adds weight to the utilisation of consumer facing non-invasive monitoring tools during the day for AF identification in high-risk populations.

Time of day dependent symptom onset is not associated with left ventricular function and myocardial damage after ST-segment elevation myocardial infarction

Abstract Background Circadian processes are suggested to influence ischemic injury in ST-segment elevation myocardial infarction (STEMI). Observational data suspect a circadian dependence of the occurrence of microvascular obstruction (MVO) in patients with STEMI. However, these observations derive from a small sample size and circadian variations in left ventricular function and myocardial damage after STEMI are still a matter of controversy. Purpose We aimed to investigate the association of time of day dependent symptom onset with left ventricular ejection fraction (LVEF), infarct size (IS) and MVO in a large cohort of STEMI patients treated with primary percutaneous coronary intervention (PCI). Methods This observational study investigated acute STEMI patients treated with primary PCI. Cardiac magnetic resonance (CMR) imaging was performed within 1 week after the index event for the determination of left ventricular function and infarct characteristics. The time of symptom onset was used to discriminate patients according to LVEF, IS as well as MVO occurrence and extent over a 24 hours cycle to evaluate circadian behavior. Results In final analysis, 889 acute STEMI patients treated with primary PCI with a delay of 189 [120-315] minutes were included. Median age of the overall cohort was 57 [51-66] years and 17% were female. Median LVEF was 49 [42-55]%, IS assumed 15.5 [8.0-24.7]% of left ventricular myocardial mass (LVMM) and MVO occurred in 57% of STEMI patients. No hourly differences between symptom onset and MVO occurrence (p=0.108), MVO extent (p=0.735), LVEF (p=0.644) and IS (p=0.722) have been evaluated. When comparing 3 hourly segments of symptom onset, no variations in MVO occurrence (p=0.114), MVO extent (p=0.308), LVEF (p=0.547) and IS (p=0.405) were observed. Conclusions No circadian variations in symptom onset and the occurrence and extent of MVO, LVEF and IS were observed in this large cohort of STEMI patients treated with primary PCI. Further research is needed to investigate the complex interplay between circadian processes and ischemic injury in this patient population.

Deep night: critical periods for the onset of acute myocardial infarction in obstructive sleep apnea patients

Abstract Introduction Obstructive sleep apnea (OSA) is associated with acute nocturnal hemodynamic and neurohormonal abnormalities that may increase the risk of coronary events, especially during deep sleeping time. This study sought to investigate the circadian variation of onset of acute myocardial infarction (AMI) in OSA patients and its long-term prognosis. Purpose In this study, we tested the hypothesis that people with OSA are more likely to have AMI during deep sleeping time than the other six-hour intervals of the day. Additionally, we assess the impact of circadian symptom-onset patterns of AMI on prognosis in OSA patients. Methods We prospectively enrolled 397 patients with AMI, for which the time of onset of chest pain was clearly identified. All subjects were categorized into non-OSA (n = 280) and OSA (n = 117) groups. The association between AMI onset time and major adverse cardiovascular and cerebrovascular events (MACCEs) was estimated by Cox proportional hazards regression. Results AMI onset occurred from midnight to 6 a.m. in 33% of OSA patients, as compared with 15% in non-OSA patients (P < 0.01). For OSA people, the relative risk of AMI from midnight to 6 a.m. was 1.990 (95% CI 1.329-2.929) compared with non-OSA patients (Figure 1). After a median of 2.89 ± 0.78 years follow-up, symptom onset time was significantly associated with risks of MACCEs in OSA patients, but not in non-OSA patients. The hazard ratios (HRs) for OSA patients were 4.683 (95% CI 2.024 to 21.409) for midnight to 6 a.m., and 6.964 (95% CI 1.379 to 35.169) for 6 p.m. to midnight as compared with AMI presenting during noon to 6 p.m (Figure 2). Conclusion Patients with OSA showed a peak incidence of AMI during the deep night, which was independently associated with adverse events.Figure 1Figure 2

P75NTR promotes tooth rhythmic mineralization via upregulation of BMAL1/CLOCK.

The circadian clock plays a critical role in dentomaxillofacial development. Tooth biomineralization is characterized by the circadian clock; however, the mechanisms underlying the coordination of circadian rhythms with tooth development and biomineralization remain unclear. The p75 neurotrophin receptor (p75NTR) is a clock factor that regulates the oscillatory components of the circadian rhythm. This study aims to investigate the impact of p75NTR on the rhythmic mineralization of teeth and elucidate its underlying molecular mechanisms. We generated p75NTR knockout mice to examine the effects of p75NTR deficiency on tooth mineralization. Ectomesenchymal stem cells (EMSCs), derived from mouse tooth germs, were used for in vitro experiments. Results showed a reduction in tooth mineral density and daily mineralization rate in p75NTR knockout mice. Deletion of p75NTR decreased the expression of DMP1, DSPP, RUNX2, and ALP in tooth germ. Odontogenic differentiation and mineralization of EMSCs were activated by p75NTR. Histological results demonstrated predominant detection of p75NTR protein in odontoblasts and stratum intermedium cells during rapid formation phases of dental hard tissue. The mRNA expression of p75NTR exhibited circadian variations in tooth germs and EMSCs, consistent with the expression patterns of the core clock genes Bmal1 and Clock. The upregulation of BMAL1/CLOCK expression by p75NTR positively regulated the mineralization ability of EMSCs, whereas BMAL1 and CLOCK exerted a negative feedback regulation on p75NTR by inhibiting its promoter activity. Our findings suggest that p75NTR is necessary to maintain normal tooth biomineralization. Odontogenic differentiation and mineralization of EMSCs is regulated by the p75NTR-BMAL1/CLOCK signaling axis. These findings offer valuable insights into the associations between circadian rhythms, tooth development, and biomineralization.

Abstract 14513: A Bayesian Analysis of Circadian Variation in Sudden Death in Wake County, North Carolina

Introduction: Sudden death is often attributed to coronary artery disease. Demonstrating that sudden death exhibits a different circadian profile than coronary artery disease would support the emerging concept that sudden death is a syndrome, with multiple etiologies. Hypothesis: Sudden death will demonstrate a circadian peak with deaths more frequent in the morning hours. Methods: The study analyzed 399 sudden death victims aged 18-64 attended by Wake County Emergency Medical Services (EMS) from 2013 to 2015. Time of death was determined using EMS records and medical examiner reports. When time of death could not be reliably determined for a victim, the victim was removed from the study. Only 169 deaths (42.3%) where time of death was reliably known to within one hour were included in the final analysis. Bayesian hierarchical modeling identified the location and/or absence of peak times for sudden death victims overall and subgroups with heart failure (19), coronary artery disease (40), hypertension (89), and respiratory disorders (48). Results: Time of death for all-cause sudden death victims spanned from 6:30 AM to noon, with no evidence of a specific, circadian peak. However, sudden death victims with underlying chronic heart failure displayed a strong circadian peak around 7:00 AM, while respiratory disorder cases showed a limited peak in the mid to late morning. Victims with coronary artery disease and hypertension exhibited no peak (Figure 1). Conclusions: Sudden death victims lack a distinct overall pattern for time of death. However, individuals with underlying heart failure and possibly respiratory diseases demonstrate a circadian pattern. These findings support the notion that sudden death has multiple causes beyond coronary artery disease. Future preventive interventions should consider the diverse etiologies of sudden death.

Resting-state background features demonstrate multidien cycles in long-term EEG device recordings

BackgroundLongitudinal EEG recorded by implanted devices is critical for understanding and managing epilepsy. Recent research reports patient-specific, multi-day cycles in device-detected epileptiform events that coincide with increased likelihood of clinical seizures. Understanding these cycles could elucidate mechanisms generating seizures and advance drug and neurostimulation therapies. Objective/hypothesisWe hypothesize that seizure-correlated cycles are present in background neural activity, independent of interictal epileptiform spikes, and that neurostimulation may temporarily interrupt these cycles. MethodsWe analyzed regularly-recorded seizure-free data epochs from 20 patients implanted with a responsive neurostimulation (RNS) device for at least 1.5 years, to explore the relationship between cycles in device-detected interictal epileptiform activity (dIEA), clinician-validated interictal spikes, background EEG features, and neurostimulation. ResultsBackground EEG features tracked the cycle phase of dIEA in all patients (AUC: 0.63 [0.56–0.67]) with a greater effect size compared to clinically annotated spike rate alone (AUC: 0.55 [0.53–0.61], p < 0.01). After accounting for circadian variation and spike rate, we observed significant population trends in elevated theta and beta band power and theta and alpha connectivity features at the cycle peaks (sign test, p < 0.05). In the period directly after stimulation we observe a decreased association between cycle phase and EEG features compared to background recordings (AUC: 0.58 [0.55–0.64]). ConclusionsOur findings suggest that seizure-correlated dIEA cycles are not solely due to epileptiform discharges but are associated with background measures of brain state; and that neurostimulation may temporarily interrupt these cycles. These results may help elucidate mechanisms underlying seizure generation, provide new biomarkers for seizure risk, and facilitate monitoring, treating, and managing epilepsy with implantable devices.

The Role of Circadian Rhythms in Stroke: A Narrative Review.

Stroke, a debilitating condition often leading to long-term disability, poses a substantial global concern and formidable challenge. The increasing incidence of stroke has drawn the attention of medical researchers and neurologists worldwide. Circadian rhythms have emerged as pivotal factors influencing stroke's onset, pathogenesis, treatment, and outcomes. To gain deeper insights into stroke, it is imperative to explore the intricate connection between circadian rhythms and stroke, spanning from molecular mechanisms to pathophysiological processes. Despite existing studies linking circadian rhythm to stroke onset, there remains a paucity of comprehensive reviews exploring its role in pathogenesis, treatment, and prognosis. This review undertakes a narrative analysis of studies investigating the relationship between circadian variation and stroke onset. It delves into the roles of various physiological factors, including blood pressure, coagulation profiles, blood cells, catecholamines, cortisol, and the timing of antihypertensive medication, which contribute to variations in circadian-related stroke risk. At a molecular level, the review elucidates the involvement of melatonin, circadian genes, and glial cells in the pathophysiology. Furthermore, it provides insights into the diverse factors influencing stroke treatment and outcomes within the context of circadian variation. The review underscores the importance of considering circadian rhythms when determining the timing of stroke interventions, emphasizing the necessity for personalized stroke management strategies that incorporate circadian rhythms. It offers valuable insights into potential molecular targets and highlights areas that require further exploration to enhance our understanding of the underlying pathophysiology. In comparison to the published literature, this manuscript distinguishes itself through its coverage of circadian rhythms' impact on stroke across the entire clinical spectrum. It presents a unique synthesis of epidemiological, clinical, molecular, and cellular evidence, underscoring their collective significance.

Circadian serum progesterone variations on the day of frozen embryo transfer in artificially prepared cycles

Research questionWhat is the intra-day variation of serum progesterone related to vaginal progesterone administration on the day of frozen embryo transfer (FET) in an artificial cycle? DesignA prospective cohort study was conducted including 22 patients undergoing a single blastocyst artificial cycle (AC)–FET from August to December 2022. Endometrial preparation was achieved by administering oestradiol valerate (2 mg three times daily) and consecutively micronized vaginal progesterone (MVP; 400 mg twice daily). A blastocyst FET was performed on the 6th day of MVP administration. Serum progesterone concentrations were measured on the day of transfer at 08:00, 12:00, 16:00 and 20:00 hours. The first and last blood samples were collected just before MVP was administered. ResultsThe mean age and body mass index of the study population were 33.95 ± 3.98 years and 23.10 ± 1.95 kg/m2. The mean P-values at 08:00, 12:00, 16:00 and 20:00 hours were 11.72 ± 4.99, 13.59 ± 6.33, 10.23 ± 3.81 and 9.28 ± 3.09 ng/ml, respectively. A significant decline, of 2.41 ng/ml (95% confidence interval 0.81–4.00), was found between the first and last progesterone measurements. ConclusionA statistically significant intra-day variation of serum progesterone concentrations on the day of FET in artificially prepared cycles was observed. This highlights the importance of a standardized procedure for the timing of progesterone measurement on the day of AC–FET. Of note, the study results are applicable only to women using MVP for luteal phase support; therefore it is necessary to confirm its validity in comparison with the different existing administration routes of progesterone.

Ritmo circadiano y presión arterial en pacientes con monitorización ambulatoria de la presión arterial y su relación con el riesgo de evento cardiovascular

IntroductionCardiovascular diseases are the group of diseases that cause most deaths worldwide, being arterial hypertension the modifiable risk factor that mostly predisposes to other cardiovascular diseases development. In this regard, ambulatory blood pressure monitoring (ABPM) lets to detect the different changes in blood pressure throughout 24h, known as circadian patterns (dipper, non-dipper, riser or extreme dipper). There may be an association between these patterns and cardiovascular risk, so this study aims to compare cardiovascular risk using the 2 validated scales REGICOR and SCORE in patients with different circadian patterns using ABMP. Material and methodsRetrospective study of hypertensive patients with ABMP registered between 2015 and 2021 in Alcázar de San Juan and Madridejos. Data were collected from clinical history (arterial hypertension, BMI, comorbidities, and smoking habits) and ABPM records, as well as sociodemographic and analytical variables, cardiovascular risk scales (REGICOR and SCORE) and circadian rhythm variables (dipper, extreme dipper, non-dipper and rise pattern). ResultsTwo hundred and sixty-nine patients (46.5% female, 64.3±12.6 years old) were included. There were 38.3% with dipper pattern, 10% extreme dipper, 33.1% non-dipper and 18.6% riser. Patients with riser pattern showed higher score on the REGICOR and SCORE scales (34 and 68%, respectively). A significant correlation was established between both scales (Spearman rho: 0.589; p<0.001), but with poor concordance (kappa=0.348 [95% CI 0.271–0.425]). ConclusionABMP has turned into a very useful tool in the diagnosis and treatment of arterial hypertension. In addition, the circadian patterns of these patients may correlate to the choice of an adequate treatment and correct follow-up.

High temperatures augment inhibition of parasites by a honey bee gut symbiont.

Temperature affects growth, metabolism, and interspecific interactions in microbial communities. Within animal hosts, gut bacterial symbionts can provide resistance to parasitic infections. Both infection and populations of symbionts can be shaped by the host body temperature. However, the effects of temperature on the antiparasitic activities of gut symbionts have seldom been explored. The Lactobacillus-rich gut microbiota of facultatively endothermic honey bees is subject to seasonal and ontogenetic changes in host temperature that could alter the effects of symbionts against parasites. We used cell cultures of a Lactobacillus symbiont and an important trypanosomatid gut parasite of honey bees to test the potential for temperature to shape parasite-symbiont interactions. We found that symbionts showed greater heat tolerance than parasites and chemically inhibited parasite growth via production of acids. Acceleration of symbiont growth and acid production at high temperatures resulted in progressively stronger antiparasitic effects across a temperature range typical of bee colonies. Consequently, the presence of symbionts reduced both the peak growth rate and heat tolerance of parasites. Substantial changes in parasite-symbiont interactions were evident over a temperature breadth that parallels changes in diverse animals exhibiting infection-related fevers and the amplitude of circadian temperature variation typical of endothermic birds and mammals, implying the frequent potential for temperature to alter symbiont-mediated resistance to parasites in endo- and ectothermic hosts. Results suggest that the endothermic behavior of honey bees could enhance the impacts of gut symbionts on parasites, implicating thermoregulation as a reinforcer of core symbioses and possibly microbiome-mediated antiparasitic defense. IMPORTANCE Two factors that shape the resistance of animals to infection are body temperature and gut microbiota. However, temperature can also alter interactions among microbes, raising the question of whether and how temperature changes the antiparasitic effects of gut microbiota. Honey bees are agriculturally important hosts of diverse parasites and infection-mitigating gut microbes. They can also socially regulate their body temperatures to an extent unusual for an insect. We show that high temperatures found in honey bee colonies augment the ability of a gut bacterial symbiont to inhibit the growth of a common bee parasite, reducing the parasite's ability to grow at high temperatures. This suggests that fluctuations in colony and body temperatures across life stages and seasons could alter the protective value of bees' gut microbiota against parasites, and that temperature-driven changes in gut microbiota could be an underappreciated mechanism by which temperature-including endothermy and fever-alters animal infection.

Time-related variations in viability of random pattern skin flaps: An experimental study in rats

ABSTRACT Chronobiological variations are in the fabric of life. The first ideas regarding the possible effects of circadian rhythm on surgical outcomes were published in the early 2000s. Some studies support and oppose this idea. The lack of experimental evidence in a controlled setting has led to this study. This study aimed to explore the chronobiological implications of surgical outcomes. The rats were divided into four groups. A random pattern dorsal skin flaps were elevated in all groups at six h intervals. Flap necrosis rates and melatonin, oxidant, and antioxidant factors were studied. Flap survival was better in the 06:00 h group. The flap necrosis was higher in the 18:00 h group. Some of the biochemical parameters displayed circadian variations. As an independent variable, the time of surgical intervention changed the flap survival rates. It should be noted that the study was held in a nocturnal animal model thus the pattern of flap survival can be in reversed fashion in a clinical scenario. This study is the first experimental evidence for “Chronosurgery” in a controlled setting. Further studies in all aspects of surgical disciplines are required.

Circadian- and wake-dependent influences on face-name memory in healthy men and women over 3 weeks of chronic sleep restriction

ObjectivesFacial recognition is one of the key functions of the human brain, and linking a face to a name is critical in many social and occupational settings. This study assessed circadian- and wake-dependent effects on face-name recognition in healthy adults. MethodsThirteen healthy adults (20-70years; 7 F) were studied in a 39-day inpatient protocol that included 3weeks of 28 hours forced desynchrony with sleep restriction (6.5:21.5 hours sleep:wake). Starting 3 hours after scheduled wake, 6 novel face-name pairs were presented every 4 waking hours; recognition was tested 2 hours later. Performance data were averaged across ∼4 hours circadian phase or time-awake bins. ResultsFace-name recognition deteriorated with increased time awake (p < .0001) and exhibited significant circadian variation (p < .0001), with worst performance shortly after the core temperature nadir. There was a significant interaction between sex and circadian phase (p = .0177), with women performing significantly better than men at all circadian phases except 60° and 120°. Women exhibited a significantly higher amplitude than men during the third week of forced desynchrony (p < .01). ConclusionsLike many other aspects of neurobehavioral performance, recalling face-name associations is impacted by both duration of time awake and circadian phase. These results have implications for face recognition testing in medical contexts, such as in testing for dementia, because performance may be impacted by sleep deficiency and the time of testing.

Influence of the circadian cycle, sex and production stage on the reference values of parameters related to stress and pathology in porcine saliva

BackgroundThe concentration of biomarkers in saliva could be influenced by several factors not related to the specific condition under analyses, which should be considered for proper clinical interpretation. In the present study, the circadian rhythm of C-reactive protein (CRP), haptoglobin (Hp), Pig-MAP, S100A12, Cu, Zn, Adenosine deaminase (ADA), total protein (TP), total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI), cortisol and α-amylase in saliva of 20 female and 20 male pigs was investigated. Moreover, the influence of sex and production phase (post-weaning, fattening and finishing) on the concentrations of biomarkers in a total of 414 healthy pigs was studied and the reference intervals for all salivary biomarkers were calculated accordingly.ResultsAll parameters except Pig-MAP, OSI and α-amylase varied significantly along the daytime, and most of them peak around early afternoon (13–15 h). The cosinor analysis described the temporal dynamics of circadian rhythms for all parameters. The range values showed differences between male and female pigs in 8 out of the 13 biomarkers, with higher concentrations in females in comparison to male pigs. The influence of the production phase on the salivary concentrations was observed for all the biomarkers. The highest concentrations were observed for Pig-MAP, S100A12 and α-amylase in post-weaning animals, for TP in growing pigs and for OSI in finishing animals. Most of the sex-influenced biomarkers showed the highest concentrations at growing stages with some exceptions such as ADA or Hp that showed the peak at finishing and post-weaning stages respectively.ConclusionsIt is necessary to establish the optimal daytime for routine saliva sampling to avoid circadian variations and for that end, the time interval between 10:00 a.m. to 12:00 a.m. is highly recommended. The factors sex and production phase influence the concentration of biomarkers and should be considered for proper biomarker interpretation. The reference intervals presented here for each salivary biomarker will help to correctly interpret the results of these analytes and contribute to the use of saliva as a non-invasive sample for the diagnosis and monitoring of the health status of swine farms.

Review article circadian disruption in pathophysiology of diabetes mellitus

Diabetes mellitus is a leading endocrine disease with a steadily increasing incidence, and its complications impose a heavy burden on the healthcare. Although pathophysiology of diabetes mellitus has been extensively investigated through the recent decades, the role of circadian rhythms in this regard was vaguely described. Circadian rhythms comprise an autonomous system of neuroendocrine signals and transcription factors that enfold key physiological processes into a daily cycle. Circadian clocks are subdivided into central (located in the suprachiasmatic nuclei of the hypothalamus) and peripheral oscillators (located in organs and cells) which produce circadian variations in the activity of virtually all cells within the human body, including the β cells of the pancreas. Circadian rhythm disruption causes circadian desynchronization which is associated with impaired glucose metabolism and insulin secretion, thereby being considered as one of the triggers of diabetes mellitus. Production of melatonin, a master regulator of circadian rhythms and a potent antioxidant, is significantly reduced in patients with diabetes mellitus. Circadian desynchronization may be triggered by a jetlag or an eating disorder. At present, circadian disruption is viewed as an important cause for the development of diabetes mellitus, although the mechanisms of such link have not been fully elucidated hitherto and might include genetic predisposition and increased oxidative stress. Timely diagnosis and appropriate treatment of circadian disruption in patients with diabetes mellitus may ameliorate the severity or prevent diabetes complications.

Marine soundscape and its temporal acoustic characterisation in the Gulf of Oristano, Sardinia (Western Mediterranean Sea)

The soundscape of the marine environment is a combination of geophony, biophony and anthropophony. Here, the soundscape of the Gulf of Oristano, a shallow inlet on the western coast of Sardinia including a special conservation area (Habitat Directive) and a national marine protected area, was investigated. Data collection was performed during July 2019, November 2019 and May 2020 using underwater acoustic equipment. The goal of this study was to characterise the ambient sound levels (Sound Pressure Level dB re 1 μPa) and describe the main soundscape components. The soundscape exhibited significant circadian and seasonal variations: the lowest and highest median SPL values were observed in the Spring (120–140 dB re 1 μPa; post-COVID-19 pandemic lockdown) and the Summer (128–150 dB re 1 μPa) respectively. Biophony was identified and characterised as dolphins’ ‘clicks’ and crustaceans’ ‘snapping’. Shrimp activity was dominant in the summer, while dolphin passages were observed across all sampling periods, accounting for 46.4% of the total recordings. Anthropophony, namely vessel passages, was predominant in the summer during the day-time and represented up to 42% of the acoustic space in the low-frequency band. Geophony increased low-frequency noise, and represented a highly variable component of the local soundscape. The marine soundscape is a valuabletool for defining integrated management plans for marine ecosystems, allowing the assessment of habitat quality, characterisation of sound sources and evaluation of the impact of anthropogenic activities.

Association between sleep variability and time in range of glucose levels in patients with type 1 diabetes: Cross-sectional study

ObjectiveSleep and circadian disturbances emerge as novel factors influencing glycemic control in type 1 diabetes (T1D). We aimed to explore the associations among sleep, behavioral circadian parameters, self-care, and glycemic parameters in T1D. MethodsSeventy-six non–shift-working adult T1D patients participated. Blinded 7-day continuous glucose monitoring (CGM) and hemoglobin A1C (A1C) were collected. Percentages of time-in-range (glucose levels 70-180 mg/dL) and glycemic variability (measured by the coefficient of variation [%CV]) were calculated from CGM. Sleep (duration and efficiency) was recorded using 7-day actigraphy. Variability (standard deviation) of midsleep time was used to represent sleep variability. Nonparametric behavioral circadian variables were derived from actigraphy activity recordings. Self-care was measured by diabetes self-management questionnaire-revised. Multiple regression analyses were performed to identify independent predictors of glycemic parameters. ResultsMedian (interquartile range) age was 34.0 (27.2, 43.1) years, 48 (63.2%) were female, and median (interquartile range) A1C was 6.8% (6.2, 7.4). Sleep duration, efficiency, and nonparametric behavioral circadian variables were not associated with glycemic parameters. After adjusting for age, sex, insulin delivery mode/CGM use, and ethnicity, each hour increase in sleep variability was associated with 9.64% less time-in-range (B = −9.64, 95% confidence interval [−16.29, −2.99], p ≤ .001). A higher diabetes self-management questionnaire score was an independent predictor of lower A1C (B = −0.18, 95% confidence interval [−0.32, −0.04]). ConclusionGreater sleep timing variability is independently associated with less time spent in the desirable glucose range in this T1D cohort. Reducing sleep timing variability could potentially lead to improved metabolic control and should be explored in future research. Data availability statementData are available upon a reasonable request to the corresponding author.

Observational analysiS of out-of-hospital Cardiac Arrest occurRence and temporal variability patterns in subpopulation of southern POLand from 2006 to 2018: OSCAR-POL registry.

Temporal variability of out-of-hospital cardiac arrest (OHCA) occurrence was presented in previous studies, however, the data regarding long-term observation is scarce. The aim of this study was to investigate the temporal variability of OHCA occurrence during a long-time period and analyze the circadian pattern within particular timeframes. The retrospective analysis of 5058 OHCA cases was made covering the period from January 1st, 2006 to December 31st, 2018. Circadian, weekly, monthly and seasonal variabilities were investigated. The circadian variability of OHCA occurrence was assessed within particular years, seasons of the year, and days of the week. The highest OHCA incidence was observed between 08:00 and 08:59 and the lowest between 01:00 and 01:59 (7.1% vs. 1.6%, p < 0.001). After division into 6-h intervals, a significantly lower number of OHCA cases occurred between 00:00 and 05:59 (12.3%) in comparison to the highest number observed in between 06:00 and 11:59 (12.3% vs. 33.5%, p < 0.001). The highest OHCA occurrence was observed on Monday (14.9%), however, no weekly variability was found (p = 0.557). The highest OHCA occurrence was observed in the winter and lowest in the summer (27.4% vs. 22.8%, p < 0.001). Significant circadian variability was observed for every day of the week, every season and year during the observation period (p < 0.001). Circadian, monthly and seasonal variability of OHCA occurrence was confirmed in the long-term observation with no differences between particular days of the week. Significant circadian variability was observed within days of the week, seasons of the year, and particular years.

INDICATORS OF CIRCUITAL HEART RHYTHM IN SCHOOLCHILDREN WITH CARDIAC NEUROCERCULATORY DYSTONIA RESIDING IN THE ANDIJAN REGION

Annotation. According to the international systematization of diseases (10th revision), neurocirculatory dystonia (NCD) refers to somatoform autonomic dysfunction that occurs with a violation of the nervous regulation of the circulatory system. Among non-infectious diseases of childhood and adolescence, vegetative-vascular dystonia is considered the most common pathology with a frequency of 4.8 to 29.1%. It is known that vegetative-vascular dystonia or its variant neurocircular dystonia is considered a predictor of arterial hypertension, atherosclerosis and coronary heart disease at a young age. Currently, determination of heart rate variability (HRV) is recognized as the most informative non-invasive method for quantitative assessment of the autonomic regulation of heart rate. The purpose of the study was a comparative assessment of the variability of circadian rhythm and heart rate in adolescents with similar neurocirculatory dystonia living in urban and rural areas. Materials and methods. We examined 77 adolescents aged 12 to 17 years (average age 14.5±0.35 years, boys -31, girls -46), hospitalized with a diagnosis of somatoform autonomic dysfunction, cardiac type NCD, from January 2022 to February 2023. Information is classified by age and place of residence (urban, rural). Taking into account the mechanisms of development of the autonomic nervous system, 2 age groups were identified. 1st age group - children 12-14 years old 49.5±4.99% (average age 13.4±0.24 years), of which 62.5±8.83% lived in Andijan (group IA), 37.5±11.74% of adolescents - in rural areas of Andijan region (group IB). 2nd age group - teenagers 15-17 years old 50.5±4.99% (average age 16.5±0.29), of which 61.2±8.89% of young people lived in Andijan (group IIA), 38.8±11.49% - in rural areas (group IIB). All teenagers live in the Andijan region every day. Results. Among the examined adolescents with NCD of the heart, complaints of pain in the heart area were similar (in age group I - 70.8±6.56%, in age group II - in 83.7±5.28% of those examined). The pain was mostly temporary (lasting a few seconds) and stabbing in nature. Interruptions in heart function were noted by 43.8±7.16% of young people in group I and 55.1±7.11% of young people in age group II. In addition, 31.3±6.69% of adolescents in age group I and 36.7±6.89% of young people in group II complained of headache, dizziness, impotence, and excessive fatigue. Conclusions. When examining adolescents with neurocirculatory dystonia, it is necessary to conduct not only a normal ECG at rest, but also Holter ECG monitoring with determination of heart rate variability; the examination will ensure adequate treatment and monitoring of this group of patients. The detected changes in the circadian rhythm and rhythm variability in urban adolescents compared to rural ones are probably associated with living in an industrial zone, environmental criteria, nutrition, and an even greater information load, which urgently requires further research.

Circadian rhythms in colonic function.

A rhythmic expression of clock genes occurs within the cells of multiple organs and tissues throughout the body, termed "peripheral clocks." Peripheral clocks are subject to entrainment by a multitude of factors, many of which are directly or indirectly controlled by the light-entrainable clock located in the suprachiasmatic nucleus of the hypothalamus. Peripheral clocks occur in the gastrointestinal tract, notably the epithelia whose functions include regulation of absorption, permeability, and secretion of hormones; and in the myenteric plexus, which is the intrinsic neural network principally responsible for the coordination of muscular activity in the gut. This review focuses on the physiological circadian variation of major colonic functions and their entraining mechanisms, including colonic motility, absorption, hormone secretion, permeability, and pain signalling. Pathophysiological states such as irritable bowel syndrome and ulcerative colitis and their interactions with circadian rhythmicity are also described. Finally, the classic circadian hormone melatonin is discussed, which is expressed in the gut in greater quantities than the pineal gland, and whose exogenous use has been of therapeutic interest in treating colonic pathophysiological states, including those exacerbated by chronic circadian disruption.

Circadian Variation in Human Milk Hormones and Macronutrients.

There is an inadequate understanding of the daily variations in hormones and macronutrients in human milk (HM), and sample collection protocols vary considerably from study to study. To investigate changes in these milk components across 24 h, 22 lactating women collected small milk samples before and after each breastfeed or expression from each breast. Test weighing was used to determine the volume of HM consumed in each feed. The concentrations of leptin, adiponectin, insulin, fat, and glucose were measured, and the intakes were calculated. A linear mixed model was fitted to assess within-feed and circadian variation in HM feed volume and concentration, and intakes of several components. The average infant intake of HM was 879 g/24 h. Significantly higher pre-feed concentrations were found for adiponectin and glucose and lower post-feed concentrations were found for insulin and fat. Significant circadian rhythms were displayed for leptin, adiponectin, insulin, glucose (both concentration and intake), fat concentration, and milk volume. These findings demonstrate the necessity for setting up standardised and rigorous sampling procedures that consider both within-feed and circadian variations in HM components to gain a more precise understanding of the impacts of these components on infant health, growth and development.