Restless Legs Syndrome: Known Knowns and Known Unknowns

Although restless legs syndrome (RLS) is a common neurological disorder, it remains poorly understood from both clinical and pathophysiological perspectives. RLS is classified among sleep-related movement disorders, namely, conditions characterized by simple, often stereotyped movements occurring during sleep. However, several clinical, neurophysiological and neuroimaging observations question this view. The aim of the present review is to summarize and query some of the current concepts (known knowns) and to identify open questions (known unknowns) on RLS pathophysiology. Based on several lines of evidence, we propose that RLS should be viewed as a disorder of sensorimotor interaction with a typical circadian pattern of occurrence, possibly arising from neurochemical dysfunction and abnormal excitability in different brain structures.

Salivary Cortisol Patterns in People Living With Dementia

Salivary cortisol has a well-documented circadian pattern in older adults. Yet, the pattern of salivary cortisol in persons living with dementia (PLWD) due to circadian rhythm disturbances is unknown. This study examined diurnal salivary cortisol patterns in 176 PLWD (mean age 73.6±8.8, 33.3% male, clinical dementia rating >=0.5) by collecting saliva at waking (AM1), 30 minutes after waking (AM2) and bedtime (PM) over two consecutive days. Cortisol awakening response (CAR) was calculated as the change between AM2 and AM1 cortisol levels. The mean baseline salivary cortisol levels (ug/dl) were 0.35 (SD:0.3) at AM1, 0.40 (SD:0.39) at AM2, and 0.19 (SD:0.4) at PM. On average, cortisol levels decreased from morning to evening, with 58% exhibiting a positive CAR (mean 0.05; SD:0.34). There were no significant associations between cortisol levels with age, sex, obesity, and comorbidities. The findings demonstrated that diurnal cortisol rhythms are maintained in PLWD with a flattened CAR.

Abstract 10847: Circadian Variation of In-Hospital and Out-of-Hospital Sudden Cardiac Arrest

Introduction: Several studies have reported circadian periodicity of sudden cardiac arrest (SCA), most commonly a nadir in event frequency during overnight hours. It remains unclear to what extent this circadian pattern is influenced by variation in patients’ physical activities. One way to elucidate this is to compare patients with out-of-hospital (OHCA) versus in-hospital (IHCA) cardiac arrests, which has not been previously done. We hypothesize that the circadian pattern of SCA will be preserved in a mixed contemporary cohort of OHCA and IHCA survivors. Methods: A total of 1,433 consecutive survivors of SCA in the Pittsburgh area from 2002 to 2012 were included. Patient demographics including clinical histories and details of SCA were collected using records from emergency medical services and rapid response teams. Unwitnessed SCA and those with potential non-cardiac confounders were excluded. The distribution of SCA throughout the day and associated patient characteristics were tested for differences using chi-square test and student’s t-test. Results: Of the 1,224 patients analyzed, 706 had IHCA and 518 OHCA. We observed a nadir of SCA in the nighttime hours between 0000 - 0600 in both IHCA and OHCA groups (p<0.001). Patients who arrested in this nighttime window had more co-morbidities (p=0.01) and lower percent of angiographically confirmed acute myocardial infarction (p=0.025). A similar circadian pattern was noted for patients with higher or lower comorbidity burden (p<0.001), although more blunted in sicker patients, as well as for patients whose arrest was due to a shockable rhythm (p<0.001). Correspondingly, the IHCA group had higher co-morbidity burden (p<0.001) and a blunted nighttime nadir compared to the OHCA group (p<0.001). We did not observe a temporal variation by day of week but did see a seasonal pattern with a peak in SCA in the Pittsburgh cold months (p<0.001). Conclusion: The typical pattern of nighttime nadir in SCA is seen in both OHCA and IHCA but is more blunted in sicker patients and in the hospital. This suggests a common mechanism that transcends differences between the two settings but may be influenced by non-cardiac comorbidities or environmental factors such as activity level.

Association of Sleep and Circadian Patterns and Genetic Risk with Incident Type 2 Diabetes: A Large Prospective Population-Based Cohort Study

Objective To examine the association of incident type 2 diabetes (T2D) risk with sleep factors, genetic risk, and their combination effects. Design Large prospective population-based cohort study. Methods This population-based prospective cohort study included 360 403 (mean [SD] age: 56.6 [8.0] years) participants without T2D at baseline from the UK Biobank. Genetic risk was categorized as high (highest quintile), intermediate (quintiles 2 to 4), and low (lowest quintile) based on a polygenic risk score for T2D. Sleep scores, including long or short sleep duration, insomnia, snoring, late chronotype, and excessive daytime sleepiness, were categorized as an unfavourable, intermediate, or favourable sleep and circadian pattern. Results During a median follow-up of 9.0 years, 13 120 incident T2D cases were recorded. Among the participants with an unfavourable sleep and circadian pattern, 6.96% (95% CI, 6.68%–7.24%) developed T2D versus 2.37% (95% CI, 2.28%–2.46%) of participants with a favourable sleep and circadian pattern (adjusted HR: 1.53, 95% CI: 1.45–1.62). Of participants with a high genetic risk, 5.53% (95% CI, 5.36%–5.69%) developed T2D versus 2.01% (95% CI, 1.91%–2.11%) of participants with a low genetic risk (adjusted HR: 2.89, 95% CI: 2.72–3.07). The association with sleep and circadian patterns was independent of genetic risk strata. Participants in the lowest quintile with an unfavourable sleep and circadian pattern were 3.97-fold more likely to develop T2D than those in the lowest quintile with a favourable sleep and circadian pattern. Conclusions Sleep and circadian patterns and genetic risk were independently associated with incident T2D. These results indicate the benefits of adhering to a healthy sleep and circadian pattern in entire populations, independent of genetic risk.

Gender identity and sexual experience affect mating behaviour and chemical profile in the lesser mealworm, Alphitobius diaperinus (Coleoptera: Tenebrionidae)

Alphitobius diaperinus (Coleoptera: Tenebrionidae), the lesser mealworm, is one of the most significant pests of the poultry industry worldwide. These insects cause structural damage in poultry houses and transmit several diseases, impacting chickens' productivity and rearing costs. Although semiochemicals may offer alternative insect pest management strategies, basic information regarding pheromone identity and their role on the behavioural ecology according to their circadian pattern of sexual behaviour of A. diaperinus is essentially lacking. This study is aimed to analyse the relation of gender identity and sexual experience of adults of A. diaperinus on their mating behaviour and whether this response is related to their CHC profiles secreted. The following steps were taken to achieve the study’s goal. First, the circadian pattern of their sexual activity was observed in newly emerged pairs for at least twenty-one days (virgin adults) and experienced adults collected from the field to identify a difference based on their sexual experience and achieve the optimal mating season to develop the following assays. Subsequently, Y-tube olfactometer bioassays were conducted to evaluate their odour bouquet attraction based on gender and sexual experience. Additionally, mating behaviour bioassays were conducted to evaluate the two factor effects. Finally, cuticular analysis was performed using gas chromatography-mass spectrometry to evaluate possible chemical differences based on the two factors. With statistical and multivariate analysis, we found that behavioural, mating and chemical responses are different based on their sexual experience. The mating sequences were described into precopulatory, copulatory and postcopulatory phases. This finding gives us a deeper understanding of the sexual communication during mating. In summary, our findings provide new insights into the mating system and chemical ecology of A. diaperinus . The results presented here may serve as a base for further studies to develop strategies for managing this pest.

Which species discovers novel food sources first? A camera trap study in a natural environment

Birds underlie a predation-starvation risk, and foraging should show a diurnal/circadian pattern. Camera traps were used to study visitation patterns and discovery of a novel food source in woodland birds in SW Germany. A total of 18 species occurred at feeders with nine of them being exploratory species. Great Tits (Parus major) discovered novel food sources first in most instances, and first discoveries occurred on average at 10:38, while it took 97 h for the first detection of the food source. Population size was correlated with discovery. The study supports the predation-starvation risk hypothesis with discovery of food sources in the morning.

Influence of Circadian Rhythm in the Eye: Significance of Melatonin in Glaucoma

Circadian rhythm and the molecules involved in it, such as melanopsin and melatonin, play an important role in the eye to regulate the homeostasis and even to treat some ocular conditions. As a result, many ocular pathologies like dry eye, corneal wound healing, cataracts, myopia, retinal diseases, and glaucoma are affected by this cycle. This review will summarize the current scientific literature about the influence of circadian patterns on the eye, focusing on its relationship with increased intraocular pressure (IOP) fluctuations and glaucoma. Regarding treatments, two ways should be studied: the first one, to analyze if some treatments could improve their effect on the ocular disease when their posology is established in function of circadian patterns, and the second one, to evaluate new drugs to treat eye pathologies related to the circadian rhythm, as it has been stated with melatonin or its analogs, that not only could be used as the main treatment but as coadjutant, improving the circadian pattern or its antioxidant and antiangiogenic properties.