Subjective time runs faster under the influence of bright rather than dim light conditions during the forenoon

The study investigated if 6 h morning bright light exposure, compared with dim light exposure, could influence time sense (range: 5-15 s). Eight women served as participants. The participant entered a bioclimatic chamber at 10:00 h on the day before the test day, where an ambient temperature and relative humidity were controlled at 25 degrees C and 60%RH. She sat quietly in a sofa in 50 lx until 22:00 h, retired at 22:00 h and then slept in total darkness. She rose at 07:00 h the following morning and again sat quietly in a sofa till 13:00 h, either in bright (2500 lx) or dim light (50 lx), the order of light intensities between the two occasions being randomized. The time-estimation test was performed from 13:00 to 13:10 h in 200 lx. The participant estimated the time that had elapsed between two buzzers, ranging over 5-15 s, and inputting the estimate into a computer. The test was carried out separately upon each individual. Results showed that the participants estimated higher durations of the given time intervals after previous exposure to 6 h of bright rather than dim light. The finding is discussed in terms of different load errors (difference between the actual core temperature and its thermoregulatory set-point) following 6-h exposure to bright or dim light in the morning.     

Alexithymia and grief reactions in bereaved Japanese women

To examine the relationship between grief reactions and alexithymia, 54 Japanese women (33 outpatients attending a psychosomatic clinic and 21 normal healthy participants) completed the Texas Inventory of Grief (TIG), the 20-item Toronto Alexithymia Scale (TAS-20), and the Profile of Mood States (POMS). Each woman had experienced the death of a spouse or a first-degree relative. The TIG scores were positively correlated to the scores on the first TAS-20 factor of Difficulty Identifying Feelings and on the POMS tension-anxiety and depression scales. The scores on the first TAS-20 factor were higher in the psychosomatic group than in the normal group. Complicated grief reactions may be closely associated with both alexithymic character and mood states in bereaved Japanese women.     

Stiffness parameter β as a predictor of the 4-year all-cause mortality of chronic hemodialysis patients

Background

There is a lack of information on stiffness parameter β, an index of arterial stiffness, in hemodialysis (HD) patients. The aim of the present study was to investigate whether stiffness parameter β is predictive of the long-term mortality of chronic HD patients.

Methods

We measured biochemical parameters and the stiffness parameter β of 80 patients on maintenance HD therapy and followed their course for 4 years, and we enrolled 70 of these 80 patients in the study. We divided the 70 patients into tertiles according to their stiffness parameter β values, and conducted multivariate analyses to examine the impact of the tertiles on 4-year mortality.

Results

Older age and the presence of diabetes mellitus were found to be independently associated with higher stiffness parameter β values. Fifteen patients (21.4 %) died and 16 (22.9 %) experienced a new cardiovascular event during the follow-up period. The results of a Kaplan–Meier analysis revealed a significantly higher risk of all-cause mortality in the HD patients with highest stiffness parameter β values (p = 0.0106). According to the ROC curve, the cut-off level that yielded maximal sensitivity and specificity for predicting all-cause mortality was 10.1, and the sensitivity and specificity using the cut-off value were 69.2 and 70.2 %, respectively.

Conclusion

The results of this study suggest that stiffness parameter β is a predictor of all-cause mortality in chronic HD patients.     

Estimated respiratory arousal threshold in patients with rapid eye movement obstructive sleep apnea

Purpose

Rapid eye movement (REM) obstructive sleep apnea (OSA) is a prevalent clinical phenotype. However, the literature focusing on the pathophysiology of REM OSA is limited. This study compared the proportion of individuals with a low respiratory arousal threshold between patients with REM and non-REM OSA.

Methods

REM OSA was defined as having an apnea–hypopnea index (AHI)?≥?5 and AHI during REM (AHI-REM)/AHI during NREM (AHI-NREM)?≥?2. REM OSA was sub-divided into REM-predominant OSA and REM-isolated OSA. REM-predominant OSA was defined as satisfying the definition of REM OSA and having an AHI-NREM?≥?5. REM-isolated OSA was defined as satisfying the definition of REM OSA and having an AHI-NREM?<?5. Patients with an AHI-REM/AHI-NREM?<?2 were defined as having non-REM OSA. A low respiratory arousal threshold was defined as having 2 or more of the following conditions: AHI?<?30 events/h, proportion of hypopnea?>?58.3%, and nadir SpO₂?>?82.5%.

Results

The proportions of individuals with low respiratory arousal thresholds among individuals with REM-predominant OSA and REM-isolated OSA were significantly higher (77.2% and 93.7%, respectively) than that of patients with non-REM OSA (48.6%). This was also true when the analysis was performed according to sex.

Conclusion

These results indicate that a low respiratory arousal threshold might be an important endotype that contributes to the pathogenesis of REM OSA, especially in REM-isolated OSA.

     

Associations of dietary intake and plasma concentrations of eicosapentaenoic and docosahexaenoic acid with prenatal depressive symptoms in Japan

The association between depression and omega‐3 polyunsaturated fatty acids, including eicosapentaenoic and docosahexaenoic acid, continues to gain focus. In this study, we examined whether dietary intakes and plasma concentrations of eicosapentaenoic and docosahexaenoic acid were associated with depressive symptoms during pregnancy. Healthy Japanese women with singleton pregnancies were recruited at a university hospital in Tokyo between 2010 and 2012. The depressive‐symptom group included participants with Edinburgh Postnatal Depression Scale scores greater than eight. Of the 329 participants, 19 (5.8%) had depressive symptoms. Lower plasma docosahexaenoic acid concentration was significantly associated with prenatal depressive symptoms. Women with depressive symptoms had a higher rate of pregnancy‐associated nausea than those with non‐depressive symptoms (52.6% vs 28.7%, respectively). Although we adjusted for the presence of pregnancy‐associated nausea, dietary fatty acid intake was not associated with depressive symptoms in the multiple logistic regression analyses. Further large studies would be required to examine any preventive effect of dietary fatty acid intake on depressive symptoms among pregnant women.     

Human blood metabolite timetable indicates internal body time

A convenient way to estimate internal body time (BT) is essential for chronotherapy and time-restricted feeding, both of which use body-time information to maximize potency and minimize toxicity during drug administration and feeding, respectively. Previously, we proposed a molecular timetable based on circadian-oscillating substances in multiple mouse organs or blood to estimate internal body time from samples taken at only a few time points. Here we applied this molecular-timetable concept to estimate and evaluate internal body time in humans. We constructed a 1.5-d reference timetable of oscillating metabolites in human blood samples with 2-h sampling frequency while simultaneously controlling for the confounding effects of activity level, light, temperature, sleep, and food intake. By using this metabolite timetable as a reference, we accurately determined internal body time within 3 h from just two anti-phase blood samples. Our minimally invasive, molecular-timetable method with human blood enables highly optimized and personalized medicine.