Factors affecting sleep quality in hospitalised patients.

INTRODUCTION: Hospitalised patients are at increased risk of poor sleep quality which can negatively impact on recovery and quality of life. This study aimed to assess sleep quality in hospitalised patients and explore the factors associated with poor sleep. METHODS: Prospective data were collected from 84 respiratory ward inpatients at time of discharge using a Likert scale questionnaire on contributing factors to sleep quality. Differences between groups reporting good and poor quality sleep were recorded. RESULTS: Most participants (77%) described inpatient sleep quality to be worse or much worse compared to their home environment. Noise (39%), checking of vital signs (33%) and light (24%) were most frequently identified as factors disrupting sleep. Binary logistic regression analysis demonstrated that men (OR 2.8, CI 1.1-7.4, p = 0.037) and those in shared rooms (OR 3.9, CI 1.4-10.9, p = 0.009) were more likely to be affected by noise. Younger patients (OR 0.92, CI 0.88-0.96, p < 0.001) and those in shared rooms (OR 8.5 CI 1.9-37.9, p < 0.001) were more likely to be affected by light. CONCLUSION: In conclusion, a high proportion of hospitalised respiratory patients on a medical ward reported poorer sleep quality compared to home due to operational interruptions and noise. Age, gender and room type further modified the sleep disruption. Future research should focus on whether strategies to reduce interruptions and noise will improve sleep quality and clinical outcomes.

Index assessment of periodontal status in patients on the background of administering a drug with circadian activity.

OBJECTIVE: Aim: The aim of this study was to determine the effect of application of drug with circadian activity (pioglitazone) for treatment of patients with periodontist. PATIENTS AND METHODS: Materials and Methods: Group I - 18 individuals with healthy periodontium. Group II - 12 participants with stage II, grade B periodontitis treated with a standard treatment protocol. Group III - 12 participants with stage II, grade B periodontitis, treated with a regimen that included the standard protocol along with the administration of pioglitazone prescribed at recommended times of intake. Group IV - 12 participants with stage II, grade B periodontitis treated with the standard protocol and pioglitazone against the recommended intake hours. RESULTS: Results: The Simplified Oral Hygiene Index in Group I was 0.406±0.034. In Group II, it was 2.5±0.06. In Group III, the hygiene index was 2.633±0.056 and in Group IV it was 2.5±0.059. The Papillary-Marginal-Alveolar Index in Group I was 0.033±0.004. In Group II, it was 0.366±0.011. For Group III, the PMA index was 0.38±0.012 and for Group IV it was 0.378±0.01. The Russell's Periodontal Index in Group I was 0.111±0.008. In Group II, it was 4.668±0.155. For Group III - 4.708±0.132 and for Group IV it was 4.575±0.089. The Gingival Bleeding Index (GBI) in Group I was 0.031±0.003, while in Group II, it was 0.266±0.009, in Group III, it was 0.273±0.007 and in Group IV it was 0.278±0.006. CONCLUSION: Conclusions: The administration of pioglitazone (the drug with circadian activity) according to its circadian stage indeed has a positive effect on the periodontal status changes of patients with stage II, grade B periodontitis.

The food-borne carcinogenic 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) disrupts circadian rhythms and ameliorated by pterostilbene (PSB) in Caenorhabditis elegans.

The food-borne 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a potential human carcinogen abundant in cooked meat. While circadian rhythms are crucial biological oscillations, the negative impact of PhIP on circadian systems and the potential of mitigation remain underexplored. We investigated the effects of PhIP on circadian rhythms and the mitigating effects of the phytochemical antioxidant pterostilbene (PSB) in Caenorhabditis elegans. We show that exposure to 10 µM PhIP disrupts the 24-h circadian rhythms of C. elegans, an effect mitigated by co-exposure to 100 µM PSB. In addition, PhIP-induced circadian disruption can be linked to defective oxidative stress resistance, which is associated with the DAF-16/FOXO pathway and is modulated by PSB. Molecular docking suggested that PhIP and PSB bind similarly to DAF-16. Moreover, 10 µM PhIP abolished the rhythmic expression of the core clock gene prdx-2, which is restored by 100 µM PSB. Findings from this study provide novel insight of how food-borne contaminant like PhIP may contribute to the disruption of circadian rhythms and suggest potential for PSB to mitigate these effects in higher organisms.

Machine learning reveals the transcriptional regulatory network and circadian dynamics of Synechococcus elongatus PCC 7942.

Synechococcus elongatus is an important cyanobacterium that serves as a versatile and robust model for studying circadian biology and photosynthetic metabolism. Its transcriptional regulatory network (TRN) is of fundamental interest, as it orchestrates the cell's adaptation to the environment, including its response to sunlight. Despite the previous characterization of constituent parts of the S. elongatus TRN, a comprehensive layout of its topology remains to be established. Here, we decomposed a compendium of 300 high-quality RNA sequencing datasets of the model strain PCC 7942 using independent component analysis. We obtained 57 independently modulated gene sets, or iModulons, that explain 67% of the variance in the transcriptional response and 1) accurately reflect the activity of known transcriptional regulations, 2) capture functional components of photosynthesis, 3) provide hypotheses for regulon structures and functional annotations of poorly characterized genes, and 4) describe the transcriptional shifts under dynamic light conditions. This transcriptome-wide analysis of S. elongatus provides a quantitative reconstruction of the TRN and presents a knowledge base that can guide future investigations. Our systems-level analysis also provides a global TRN structure for S. elongatus PCC 7942.

Association between chronic kidney disease stages and changes in ambulatory blood pressure monitoring parameters / Associação entre estágios da doença renal crônica e alterações dos parâmetros da monitorização ambulatorial da pressão arterial

Abstract Introduction: Blood pressure (BP) assessment affects the management of arterial hypertension (AH) in chronic kidney disease (CKD). CKD patients have specific patterns of BP behavior during ambulatory blood pressure monitoring (ABPM). Objectives: The aim of the current study was to evaluate the associations between progressive stages of CKD and changes in ABPM. Methodology: This is a cross-sectional study with 851 patients treated in outpatient clinics of a university hospital who underwent ABPM examination from January 2004 to February 2012 in order to assess the presence and control of AH. The outcomes considered were the ABPM parameters. The variable of interest was CKD staging. Confounding factors included age, sex, body mass index, smoking, cause of CKD, and use of antihypertensive drugs. Results: Systolic BP (SBP) was associated with CKD stages 3b and 5, irrespective of confounding variables. Pulse pressure was only associated with stage 5. The SBP coefficient of variation was progressively associated with stages 3a, 4 and 5, while the diastolic blood pressure (DBP) coefficient of variation showed no association. SBP reduction was associated with stages 2, 4 and 5, and the decline in DBP with stages 4 and 5. Other ABPM parameters showed no association with CKD stages after adjustments. Conclusion: Advanced stages of CKD were associated with lower nocturnal dipping and greater variability in blood pressure.

Resumo Introdução: A avaliação da pressão arterial (PA) tem impacto no manejo da hipertensão arterial (HA) na doença renal crônica (DRC). O portador de DRC apresenta padrão específico de comportamento da PA ao longo da monitorização ambulatorial da pressão arterial (MAPA). Objetivos: O objetivo do corrente estudo é avaliar as associações entre os estágios progressivos da DRC e alterações da MAPA. Metodologia: Trata-se de um estudo transversal com 851 pacientes atendidos nos ambulatórios de um hospital universitário que foram submetidos ao exame de MAPA no período de janeiro de 2004 a fevereiro de 2012 para avaliar a presença e o controle da HA. Os desfechos considerados foram os parâmetros de MAPA. A variável de interesse foi o estadiamento da DRC. Foram considerados como fatores de confusão idade, sexo, índice de massa corporal, tabagismo, causa da DRC e uso de anti-hipertensivos. Resultados: A PA sistólica (PAS) se associou aos estágios 3b e 5 da DRC, independentemente das variáveis de confusão. Pressão de pulso se associou apenas ao estágio 5. O coeficiente de variação da PAS se associou progressivamente aos estágios 3a, 4 e 5, enquanto o coeficiente de variação da pressão arterial diastólica (PAD) não demonstrou associação. O descenso da PAS obteve associação com estágios 2, 4 e 5, e o descenso da PAD, com os 4 e 5. Demais parâmetros da MAPA não obtiveram associação com os estágios da DRC após os ajustes. Conclusão: Estágios mais avançados da DRC associaram-se a menor descenso noturno e a maior variabilidade da pressão arterial.

Therapeutic use of music in neurological disorders: A concise narrative review.

Background: Music elicits multifactorial benefits in emotional, social, cognitive, and academic aspects of human life. Music is clinically proven to reduce stress and anxiety, and improve mood and self-expression, particularly after traumatic events. Studies have also demonstrated that music promotes parasympathetic autonomic systems, suppresses hyperactivation of stress responses, and boosts immune functions. However, its ability to promote brain plasticity and signalling are only beginning to be realized. Moreover, its employment as a therapy for the treatment of specific aspects of other neurological disorders, including neurodevelopmental and neurodegenerative conditions and their comorbidities, is fast becoming an interesting field of research. Objective: The aim of this review is to summarize some of the recent studies focused on evaluating the applications of music therapy. For this purpose, we have focused on disorders encompassing both temporal extremities of brain developmental stages, from developmental conditions of autism and attention deficit hyperactivity disorder (ADHD), to ageing-related pathologies of Parkinson's disease and dementias. Results: The findings of the reviewed studies indicate potent utilities of music-based interventions in beneficially affecting multiple spheres of brain functions, such as sensorimotor, auditory, communication/language, psychological/emotional, behavioural, sleep and memory and cognitive attributes of patients diagnosed with diverse neuropathologies. Nevertheless, lack of standardized protocols for music provision as well as absence of information regarding key aspects, such as cultural and musical orientations of subjects and therapists'/caregivers' attitudes, have hindered the complete realization of music's therapeutic potential for neurological conditions. Further, while some studies have undertaken assessments of core neurophysiological mechanisms underlying music therapy, this information is largely lacking for most clinical studies. Conclusion: While this is not an exhaustive review of literature, we do hope that it serves as a platform to promote future research for establishing music therapy as a relevant neurotherapeutic strategy.

Influence of shift work on sleep quality and circadian patterns of heart rate variability among nurses.

Background: Shift work implementation is essential for providing continuous patient care in hospitals. However, working in shifts on a routine basis may disrupt the circadian pattern and alter the sleep-wakefulness cycle in nurses. Stress due to shift work can influence the adaptability of the cardiovascular system, produce psychophysiological strain and deteriorate work performance in female nurses. Objective: This study investigated the effect of morning and night shift work on sleep quality and circadian patterns governing heart rate variability (HRV) in female nurses working in a tertiary care hospital. Methods: Thirty-eight healthy female nurses were recruited. Frequency and time domain parameters of HRV were recorded as markers of cardiac autonomic function. A student t-test was used to investigate differences in HRV between morning and night shift workers. Mann-Whitney non-parametric test was applied for the difference between Pittsburgh Sleep Quality Index (PSQI) scores in the two groups. Results: Standard deviation of the normal-to-normal interval (SDNN) (msec), total power (ms2) and high-frequency (HF) band power (ms2) were significantly reduced in night shift nurses than in morning shift nurses. The low-frequency (LF)/HF ratio was significantly increased in night shift nurses. The differences in standard deviation of the averages of NN intervals (SDaNN) (msec), root mean square of successive differences between adjacent NN intervals (RMSSD), mean NN, very low-frequency (VLF) band power (ms2) and LF band power (ms2) were not statistically significant. The global PSQI score was significantly higher among night shift workers than in morning shifts. Conclusion: Inadequate sleep can disrupt the body's ability to regulate heart rhythm and increase the risk of cardiovascular diseases and mortality. The research suggests a propensity for autonomic imbalance in night shift workers when compared to their counterparts on morning shifts.

Efficacy on symptoms and mortality day vs. night administration of EGFR-TKIs for advanced non-small cell lung cancer.

PURPOSE: This study has a purpose to investigate the side effects of three EGFR-TKIs targeted therapeutic agents (gefitinib, erlotinib, and afatinib) and all-cause mortality in patients with metastatic lung cancer. METHODS: We performed a prospective cohort study. We selected all patients with newly diagnosed metastatic lung cancer between January and November 2019. Main exposure was daytime versus nighttime use of targeted EGFR TKIs. The study outcome was a symptom change using the mobile application, and all-cause mortality between January 2019 and March 2023. RESULTS: Among the 87 study participants, 35 (40%) took their medication at night. Among the 87 study participants, 35 (40%) took their medication at night. At 6 weeks of treatment, acne (1.36; 95% confidence interval [CI] 1.09, 1.64; p for interaction = 0.04) and dry skin (1.35; 95% CI 1.09, 1.61, p for interaction = 0.01) in the day group showed a much increase from baseline compared to the night group. In contrast, the night group reported greater reductions in lung cancer-related symptoms from baseline compared to the day. During follow-up (median 43 months), the night group had a lower risk of all-cause death than the day group, especially in younger patients (adjusted hazard ratio = 0.34; 95% CI 0.13, 0.87). CONCLUSIONS: The group taking EGFR-TKIs at night experienced fewer side effects and had longer overall survival compared to the day group. Clinicians should consider recommending that lung cancer patients take their once-daily oral anticancer drugs in the evening rather than the morning to improve treatment outcomes.

Transcriptome Analysis Revealed ZmPTOX1 Is Required for Seedling Development and Stress Tolerance in Maize.

Plant seedling morphogenesis is considerably related to photosynthesis, pigment synthesis, and circadian periodicity during seedling development. We identified and cloned a maize zebra or crossbanding leaves mutant wk3735, which produces pale white kernels and was identified and plays a role in the equilibrium of the Redox state the in/out of ETC by active oxygen scavenging. Interestingly, it produces the zebra leaves during the production of the first seven leaves, which is apparently different from the mutation of homologs AtPTOX in Arabidopsis. It is intriguing to investigate how and why yellow crossbands (zebra leaf phenotype) emerge on leaves. As expected, chlorophyll concentration and photosynthetic efficiency both significantly declined in the yellow sector of wk3735 leaves. Meanwhile, we observed the circadian expression pattern of ZmPTOX1, which was further validated by protein interaction assays of the circadian clock protein TIM1 and ZmPTOX1. The transcriptome data of yellow (muW) and green (muG) sectors of knock-out lines and normal leaves of overexpression lines (OE) at the 5th-leaf seedling stage were analyzed. Zebra leaf etiolated sections exhibit a marked defect in the expression of genes involved in the circadian rhythm and rhythmic stress (light and cold stress) responses than green sections. According to the analysis of co-DEGs of muW vs. OE and muG vs. OE, terms linked to cell repair function were upregulated while those linked to environmental adaptability and stress response were downregulated due to the mutation of ZmPTOX1. Further gene expression level analyses of reactive oxygen species (ROS) scavenging enzymes and detection of ROS deposition indicated that ZmPTOX1 played an essential role in plant stress resistance and ROS homeostasis. The pleiotropic roles of ZmPTOX1 in plant ROS homeostasis maintenance, stress response, and circadian rhythm character may collectively explain the phenotype of zebra leaves during wk3735 seedling development.

Sex-specific chrono-nutritional patterns and association with body weight in a general population in Spain (GCAT study).

BACKGROUND: Altered meal timing patterns can disrupt the circadian system and affect metabolism. Our aim was to describe sex-specific chrono-nutritional patterns, assess their association with body mass index (BMI) and investigate the role of sleep in this relationship. METHODS: We used the 2018 questionnaire data from the population-based Genomes for Life (GCAT) (n = 7074) cohort of adults aged 40-65 in Catalonia, Spain, for cross-sectional analysis and its follow-up questionnaire data in 2023 (n = 3128) for longitudinal analysis. We conducted multivariate linear regressions to explore the association between mutually adjusted meal-timing variables (time of first meal, number of eating occasions, nighttime fasting duration) and BMI, accounting for sleep duration and quality, and additional relevant confounders including adherence to a Mediterranean diet. Finally, cluster analysis was performed to identify chrono-nutritional patterns, separately for men and women, and sociodemographic and lifestyle characteristics were compared across clusters and analyzed for associations with BMI. RESULTS: In the cross-sectional analysis, a later time of first meal (ß 1 h increase = 0.32, 95% CI 0.18, 0.47) and more eating occasions (only in women, ß 1 more eating occasion = 0.25, 95% CI 0.00, 0.51) were associated with a higher BMI, while longer nighttime fasting duration with a lower BMI (ß 1 h increase=-0.27, 95% CI -0.41, -0.13). These associations were particularly evident in premenopausal women. Longitudinal analyses corroborated the associations with time of first meal and nighttime fasting duration, particularly in men. Finally, we obtained 3 sex-specific clusters, that mostly differed in number of eating occasions and time of first meal. Clusters defined by a late first meal displayed lower education and higher unemployment in men, as well as higher BMI for both sexes. A clear "breakfast skipping" pattern was identified only in the smallest cluster in men. CONCLUSIONS: In a population-based cohort of adults in Catalonia, we found that a later time of first meal was associated with higher BMI, while longer nighttime fasting duration associated with a lower BMI, both in cross-sectional and longitudinal analyses.

Circadian regulatory networks of glucose homeostasis and its disruption as a potential cause of under-nutrition.

The circadian clock system, an evolutionarily conserved mechanism, orchestrates diurnal rhythms in biological activities such as behavior and metabolism, aligning them with the earth's 24-hour light/dark cycle. This synchronization enables organisms to anticipate and adapt to predictable environmental changes, including nutrient availability. However, modern lifestyles characterized by irregular eating and sleeping habits disrupt this synchrony, leading to metabolic disorders such as obesity and metabolic syndrome, evidenced by higher obesity rates among shift workers. Conversely, circadian disturbances are also associated with reduced nutrient absorption and an increased risk of malnutrition in populations such as the critically ill or the elderly. The precise mechanisms of these disturbances in leading to either over-nutrition or under-nutrition is complex and not yet fully understood. Glucose, a crucial energy source, is closely linked to obesity when consumed excessively and to weight loss when intake is reduced, which suggests that circadian regulation of glucose metabolism is a key factor connecting circadian disturbances with nutritional outcomes. In this review, we describe how the biological clock in various tissues regulates glucose metabolism, with a primary focus on studies utilizing animal models. Additionally, we highlight current clinical evidence supporting the association between circadian disturbance and glucose metabolism, arguing that such disruption could predominantly contribute to under-nutrition due to impaired efficient utilization of nutrients.

Abnormal circadian rhythms exacerbate dilated cardiomyopathy by reducing the ventricular mechanical strength.

AIMS: Dilated cardiomyopathy (DCM) has etiological and pathophysiological heterogeneity. Abnormal circadian rhythm (ACR) is related to the development of DCM in animal models, but exploration based on clinical samples is lacking. Sleep apnea (SA) is the most common disease related to ACR, and we chose SA as the study object to explore ACR-DCM. METHODS AND RESULTS: We included a derivation cohort (n =105) and a validation cohort (n = 65). DCM patients were divided into SA and without SA group. RT-qPCR was used to determine the change of rhythm gene expression pattern of heart samples from different timepoints. We used single-nucleus RNA sequencing (snRNA-seq) to explore the abnormal transcriptional patterns in the ACR group, and we verified the findings by pathological staining, atomic force microscopy (AFM), and Rev-erbα/ß knockout (KO) mice analysis. DCM patients with SA showed decreased amplitude of rhythm gene expression. SA group showed more severe dilation of left heart chambers. From snRNA-seq, ACR-DCM lost the morning transcriptional patterns, detailly, actin cytoskeleton organization of cardiomyocytes (CMs) disrupted and hypertrophy aggravated, and the proportion of activated fibroblasts (Fibs) decreased with the reduction of fibrotic area ratio. The results of pathological staining, mechanical experiments, and transcriptional feature of Rev-erbα/ß KO mice supported the above findings. CONCLUSION: Compared with the non-SA group, left ventricular (LV) wall dilation was more severe and the structural strength was lower in DCM patients with SA, and phenotypic changes in CM and Fib were involved in this process. ACR-DCM was histopathologically characterized by a structurally weak ventricular wall.

Association between the weight-adjusted-waist index and circadian syndrome in findings from a nationwide study.

Weight-adjusted-waist index (WWI) is an emerging parameter for evaluating obesity. We sought to ascertain the link between WWI and circadian syndrome (CircS). The study population consisted of 8275 eligible subjects who were included in the ultimate analysis from the NHANES 2011-2018. By using multivariable regression models, the association of WWI and CircS was analyzed. In subgroup analysis, we explored the relationship in different groups and tested the stability of the intergroup connection using interaction testing. To investigate whether WWI and CircS had a potential non-linear relationship, smooth curve fittings, and threshold effects tests were also constructed. In a multivariate linear regression model, WWI is significantly positively related to CircS (OR = 1.77, 95% CI 1.50-2.08). Through subgroup analysis and interaction testing, the stability of this positive association was also validated. It was further found that there was an inverted U-shaped association, with a turning point of 11.84, between WWI and CircS. Our findings supported a strong association between WWI values and CircS. Central obesity management is pivotal for preventing or alleviating CircS.

Effects of Music on Repeated-Sprint Performance of Elite Tunisian Soccer Players: Comparing Morning to Afternoon Practice Sessions.

Our aim in the present study was to examine the effect of listening to self-selected music during soccer warm-ups in morning and afternoon sessions on repeated-sprint performances of elite soccer players. Twenty elite academy male soccer players performed a repeated-sprint ability (RSA) test in the morning (i.e., 07:00 hours) and in the afternoon (i.e., 17:00 hours), with or without listening to music during the warm-up period. The RSA test consisted of six 40-meter sprints with 180° direction changes interspersed with a 20-second passive recovery period. Ratings of perceived exertion (RPE) were obtained at the end of the warm-up period and immediately after the RSA test. Results showed that listening to music during warming-up had no significant effect on these selected performance measures (i.e., mean sprint time, best sprint time, RSA decrement), regardless of whether performances were in the morning or the afternoon. Moreover, players reported higher post-warm-up RPE scores in the music listening condition than in the no-music listening condition, only in the afternoon session. Furthermore, RPE scores measured after the RSA test were higher in the no-music listening condition compared to the music listening condition, only in the morning session. Thus, the use of music during warming-up in elite soccer players appears to be an individual athlete's choice but not a reliable means of enhancing performance.

A Cross-Sectional Study of Circadian Stimulus in Swedish Radiographers' Light Environment.

Background: Timely light exposure is a vital aspect to achieve better sleep and well-being. As there are risks with a disturbed circadian rhythm and benefits with light settings that stimulate the rhythm, the circadian effective light, circadian stimulus (CS), for radiographers was examined. Aim: The aim of the study was to compare radiographers' light environment on the workstations, at a university hospital in Southern Sweden in the form of CS and relate that to recommendations published by the Swedish Environmental Protection Agency. Method: A cross-sectional method has been applied. The measurements for CS were collected in all labs in the radiology department in the middle of January. Result: A total of 804 measures were evenly collected resulting in a median for the 19 labs, where the observed median for all labs was 0.091 CS which is significantly lower than the recommended value of 0.3 CS (p < .001). Comparing work light settings with maximum light levels in the brightest and darkest labs showed a significant difference (p < .001). Conclusion: The CS values in the labs, at the radiology department at a university hospital in Southern Sweden, do not reach the recommended values of circadian stimulus published by the Swedish Environmental Protection Agency when the radiographers themselves set the light. There is a potential for improvement as a significant difference could be seen between the chosen level of light and the maximum possible level of light.

Aging abolishes circadian rhythms and disrupts temporal organization of antioxidant-prooxidant status, endogenous clock activity and neurotrophin gene expression in the rat temporal cortex.

Disruption of circadian rhythms contributes to deficits in cognitive functions during aging. Up to date, the biochemical, molecular and chronobiological bases of such deterioration have not been completely elucidated. Here, we aim: 1) to investigate the endogenous nature of 24 h-rhythms of antioxidant defenses, oxidative stress, clock's, and neurotrophic factors expression, in the rat temporal cortex (TC), and 2) to study the consequences of aging on the circadian organization of those factors. We observed a circadian organization of antioxidant enzymes activity, lipoperoxidation and the clock, BMAL1 and RORa, proteins, in the TC of young rats. Such temporal organization suggests the existence of a two-way communication among clock transcription factors and antioxidant defenses. This might generate the rhythmic and circadian expression of Bdnf and Rc3 genes involved in the TC-depending cognitive function. Noteworthy, such circadian organization disappears in the TC of aged rats. Aging also reduces glutathione peroxidase activity and expression, and it increases lipid peroxidation, throughout a 24 h-period. An increased oxidative stress makes the cellular redox environment change into an oxidative status which alters the endogenous clock activity and disrupts the circadian organization of, at least part, of the molecular basis of the synaptic plasticity in the TC.

The influence of time of day on memory recognition for faces.

Time of day can alter memory performance in general. Its influence on memory recognition performance for faces, which is important for daily encounters with new persons or testimonies, has not been investigated yet. Importantly, high levels of the stress hormone cortisol impair memory recognition, in particular for emotional material. However, some studies also reported high cortisol levels to enhance memory recognition. Since cortisol levels in the morning are usually higher than in the evening, time of day might also influence recognition performance. In this pre-registered study with a two-day design, 51 healthy men encoded pictures of male and female faces with distinct emotional expressions on day one around noon. Memory for the faces was retrieved two days later at two consecutive testing times either in the morning (high and moderately increased endogenous cortisol levels) or in the evening (low endogenous cortisol levels). Additionally, alertness as well as salivary cortisol levels at the different timepoints was assessed. Cortisol levels were significantly higher in the morning compared to the evening group as expected, while both groups did not differ in alertness. Familiarity ratings for female stimuli were significantly better when participants were tested during moderately increased endogenous cortisol levels in the morning than during low endogenous cortisol levels in the evening, a pattern which was previously also observed for stressed versus non-stressed participants. In addition, cortisol levels during that time in the morning were positively correlated with the recollection of face stimuli in general. Thus, recognition memory performance may depend on the time of day and as well as on stimulus type, such as the difference of male and female faces. Most importantly, the results suggest that cortisol may be meaningful and worth investigating when studying the effects of time of day on memory performance. This research offers both, insights into daily encounters as well as legally relevant domains as for instance testimonies.

Transient Cooling Resets Circadian Rhythms of Locomotor Activity in Lizards.

Animals frequently experience temperature fluctuations in their natural life cycle, including periods of low temperatures below their activity range. For example, poikilothermic animals are known to enter a hibernation-like state called brumation during transient cooling. However, the knowledge regarding the physiological responses of brumation is limited. Specifically, the impact of exposure to low-temperature conditions outside the range of temperature compensation on the subsequent circadian behavioral rhythms remains unclear. In this study, we investigated the effects of transient cooling on the behavioral circadian rhythm in the non-avian reptile, the bearded dragon (Pogona vitticeps). Under constant light (LL) conditions at 30 °C, the animals exhibited a free-running rhythm, and exposure to low temperatures (4 °C) caused a complete cessation of locomotion. Furthermore, we revealed that the behavioral rhythm after rewarming is determined not by the circadian phase at the onset or the duration of cooling, but by the timing of cooling cessation.

Loss of endogenous circadian clock function in mice alters respiratory cycle timing in a time of day- and sex-specific manner.

Resting breathing and ventilatory chemoreflexes are regulated in a 24-hr manner by the endogenous circadian clock. However, it is unclear how circadian biology influences different phases of the breath-to-breath respiratory cycle which are predominantly controlled by pontomedullary regions of the brainstem. Here, we performed whole-body plethysmography during quiet wakefulness in young adult male and female mice lacking the core clock gene Brain and Muscle Arnt-like 1 (BMAL1) to determine the extent to which the molecular clock affects respiratory cycle timing and ventilatory airflow mechanics. Breath waveform analysis revealed that male BMAL1 knockout (KO) mice exhibit time of day-specific differences in inspiratory and expiratory times, total cycle length, end inspiratory pause, relaxation time, and respiratory rate compared to wild-type littermates. Notably, changes in respiratory pattern were not observed in female BMAL1 KO mice when compared to wild-type females. Additionally, BMAL1 deficiency did not disrupt overall minute ventilation or peak airflow in either sex, suggesting total ventilatory function during quiet wakefulness is preserved. Taken together, these findings indicate that genetic disruption of the circadian clock in mice elicits sex-specific changes in respiratory cycle timing.

IL-6 after wake-up in human males: Exposure to red versus blue light and the interplay with cortisol.

Light is essential in shaping human circadian rhythms, including that of the hormone cortisol. While cortisol is known to influence secretion of the cytokine IL-6, the influence of light itself on IL-6 remains unclear. Thus, this study investigated the effects of two light conditions - red and blue - on IL-6 concentrations and the cortisol awakening response in blood. The interplay between cortisol and IL-6 was explored as well. The between-subject experiment was conducted with 71 healthy adult men (aged M red = 24.30, SD = 3.56; M blue = 24.40, SD = 3.51) in a standardized sleep laboratory setting with 60-min light exposure post-awakening at 05:00 a.m. Two mixed models, with light condition and time across measurement points as factors, were calculated. In the one for cortisol, chronotype was introduced as a covariate. Mean cortisol concentrations did not differ between exposure to red vs. blue light (p = 0.443), but overall cortisol output (area under the curve with respect to ground; AUCG) and sensitivity (area under the curve with respect to increase; AUCI) were greater in the blue-light condition (p = 0.050 and p < 0.001, respectively). Additionally, chronotype significantly influenced cortisol concentrations (p = 0.035). As for IL-6, a main effect of time was obtained, with increasing concentrations over time (p = 0.002). Total IL-6 secretion was greater under blue-light exposure (p <. 001), but mean IL-6 concentrations (p = 0.230) and IL-6 sensitivity (p = 0.777) did not differ between the red- and blue-light condition. Mean and total cortisol and IL-6 concentrations were significantly negatively correlated (p = 0.021 and p < 0.001, respectively) during the red-light exposure. In the blue-light condition, cortisol sensitivity was significantly negatively correlated with IL-6 sensitivity (p = 0.034). Overall, blue light seemed to have exerted a greater influence on cortisol and IL-6. For cortisol, this effect might be moderated by chronotype. Additionally, cortisol and IL-6 seem to interact under light exposure. However, these effects were mixed and could not be found consistently across mean secretion, AUCg and AUCi.