Exploring the Impact of the Microbiome on Neuroactive Steroid Levels in Germ-Free Animals

Steroid hormones are essential biomolecules for human physiology as they modulate the endocrine system, nervous function and behaviour. Recent studies have shown that the gut microbiota is directly involved in the production and metabolism of steroid hormones in the periphery. However, the influence of the gut microbiota on levels of steroids acting and present in the brain (i.e., neuroactive steroids) is not fully understood. Therefore, using liquid chromatography–tandem mass spectrometry, we assessed the levels of several neuroactive steroids in various brain areas and the plasma of germ-free (GF) male mice and conventionally colonized controls. The data obtained indicate an increase in allopregnanolone levels associated with a decrease in those of 5α-androstane-3α, 17β-diol (3α-diol) in the plasma of GF mice. Moreover, an increase of dihydroprogesterone and isoallopregnanolone in the hippocampus, cerebellum, and cerebral cortex was also reported. Changes in dihydrotestosterone and 3α-diol levels were also observed in the hippocampus of GF mice. In addition, an increase in dehydroepiandrosterone was associated with a decrease in testosterone levels in the hypothalamus of GF mice. Our findings suggest that the absence of microbes affects the neuroactive steroids in the periphery and the brain, supporting the evidence of a microbiota-mediated modulation of neuroendocrine pathways involved in preserving host brain functioning.

Potential Risks to Hearing Functions of Service Members From Exposure to Jet Fuels

Purpose Several military occupations, particularly those within the U.S. Air Force, require working with or around jet fuels. Jet fuels contain components that are known to affect central nervous function, yet effects of these fuels on auditory function, specifically auditory processing of sound, are not well understood at this time. Animal studies have demonstrated that exposure to jet fuels prior to noise exposure can exacerbate the noise exposure's effects, and service members exposed to jet fuels are at risk of noise exposure within their work environments. The purpose of this article was to give a brief synopsis of the evidence on the ototoxic effects due to jet fuel exposure to aid audiologists in their decision making when providing care for populations who are occupationally exposed to fuels or while during military service. Conclusions Exposure to jet fuels impacts central nervous function and, in combination with noise exposure, may have detrimental auditory effects that research has yet to fully explain. Additional longitudinal research is needed to explain the relationships, which have clinical implications for service members and others exposed to jet fuels. In the meantime, audiologists can gain useful information by screening for chemical exposures when obtaining patient case histories. If jet fuel exposure is suspected, the Lifetime Exposure to Noise and Solvents Questionnaire can be used to estimate a noise exposure ranking and identify other potentiating agents such as jet fuel and industrial chemicals. A history of jet fuel exposure should inform the selection of hearing tests in the audiometric evaluation and when devising the treatment plan.

Effect of napping on a bean bag chair on sleep stage, muscle activity, and heart rate variability

Although ample evidence has demonstrated that daytime napping is beneficial for health and cognitive performance, bedding for napping has not yet been scientifically investigated. In this study, we assessed the effect of a bean bag chair (BC), which would automatically adjust according to body shape and size, on daytime napping and physiological parameters related to sleep, such as electroencephalogram (EEG), electromyogram (EMG), and heart rate variability (HRV). Fourteen healthy participants were enrolled within the context of a randomized, single-blind, crossover study to evaluate the effects of a BC in comparison with those of a urethane chair manufactured to have a similar shape (UR). EEG analyses revealed no significant differences in sleep architecture or frequency components; however, a significant decrease was found in EMG recordings in the trapezius muscle, which represents the neck region (p = 0.024). Additionally, a significant main effect of bedding in the LF/RF ratio (F [1, 20] = 4.314, p = 0.037) was revealed. These results suggest that napping with a BC may provide a comfortable napping environment involving muscle relaxation and proper regulation of autonomic nervous function.

Serial Changes in Cardiac Sympathetic Nervous Function After Transcatheter Aortic Valve Replacement: A Prospective Observational Study Using 123I-meta-iodobenzylguanidine Imaging

Purpose:Transcatheter aortic valve replacement (TAVR) can rapidly improve cardiac sympathetic nervous function (CSNF) within 2 weeks in patients with aortic stenosis (AS). However, it remains unclear whether such short-term improvements will be sustained thereafter. The present study aimed to investigate the mid-term (i.e., 6–12 months) effects of TAVR on CSNF in patients with severe AS using 123I-meta-iodobenzylguanidine (MIBG) imaging.Methods:Patients with severe AS who were scheduled to undergo TAVR between October 2017 and June 2019 were enrolled in this single-centre, prospective, observational study. MIBG imaging was performed at baseline, within 2 weeks after TAVR, and at 6–12 months post-TAVR to evaluate the heart–mediastinum ratio (H/M) and washout rate (WR). Differences between each MIBG parameter at three time points were analysed, and factors involved in the long-term improvement in the late H/M were investigated. Results:Of 183 consecutive patients, 75 (19 men; median age: 86 years) were evaluated. The late H/M significantly improved within 2 weeks after TAVR (P=0.041) and further improved over 6–12 months after TAVR (P=0.041). The WR rapidly improved immediately after TAVR (P=0.003) but remained unchanged at 6–12 months (P=0.827). Multivariate analysis revealed that the baseline mean aortic valve pressure gradient (mPG) was an independent predictor of mid-term improvement in the late H/M (>0.1) (adjusted odds ratio: 0.035; 95% confidence interval: 0.004–0.070; P=0.037). Patients with a high baseline mPG (≥58 mmHg) exhibited a significantly greater increase in the late H/M than those with a low baseline mPG (<42 mmHg) (0.24 vs. 0.01; P=0.029).Conclusions:CSNF, as denoted by the late H/M, demonstrated sustained improvement from within 2 weeks after TAVR until 6–12 months later. Such improvement was related to baseline hemodynamic AS severity.

APG(Acceleration Plethysmography) Correlate with Moods in Nursing Workers with Fatigue after Work

Fatigue or stress in the workplace is a serious problem. The profession of nursing, in particular, is physically and mentally stressful, which often leads to job retrenchment, and shortage of workers. Solving this problem requires a deeper understanding of the fatigue and stress caused by work, and there is a need to consider countermeasures. Purpose: The purpose of this study is to assess the correlation between the psychological and physiological fatigue of healthy nurses during normal work, and to measure nursing stress and fatigue more conveniently. Method: We examined healthy nurses’ physiology (Acceleration Plethysmography: APG and Blood Pressure: BP) and psychology (Visual Analogue Scale: VAS and Mood Inventory Scale: MIS) before and after a normal workday. Results: We observed that after a normal days’ work, the nurses’ autonomic activity, high-frequency component power (HF), low-frequency component power/high-component power ratio (LF/HF ratio), and total power (LF་HF) increased significantly. Psychologically, VAS increased significantly, while the MIS Refreshing Mood decreased remarkably. The HF value correlated significantly with VAS and the MIS Refreshing Mood. The MIS Refreshing Mood correlates significantly with increased sympathetic and autonomic nervous function. Thus, an MIS test may alternative for physiological tests to detect fatigue more quickly and easily. Conclusion: These findings may help nurses and other workers reduce fatigue, cope with stress, and prevent illness. We hope this study will contribute towards addressing the issues related to workers’ mental health in the workplace.

Association Between Circulating Adiponectin and Heart Rate Recovery in Women With Polycystic Ovarian Syndrome

Background: Imbalance of autonomic nervous system is confirmed as a key contributor for cardiometabolic complications in polycystic ovarian syndrome (PCOS) women. Heart rate recovery (HRR) is an easy test for autonomic nervous tone evaluation and a powerful index for predicting cardiovascular events and mortality. Adiponectin (APN) is reported to be correlated closely with autonomic nervous function in different populations.Methods: This study aimed to investigate the relationship between serum total APN and HRR in PCOS women. A total of 89 PCOS women were enrolled and divided into two groups. Women with HRR values slower than 12 beats were defined as Blunted HRR Group. APN levels were compared between Blunted HRR Group and Normal HRR Group. Multivariate logistic regression analysis and multiple linear regression analysis were performed to determine which clinical variables were independently associated with decreased HRR and the effect of clinical variables on APNlevels, respectively. Results: 23 women were categorized in Blunted HRR Group, in which the APN level was significantly lower than Normal HRR Group (10.2±3.9 ug/ml vs. 13.1±4.1 ug/ml, P=0.015). Age [odds ratio (OR) = 1.15; 95% confidence interval (CI) = 1.04-1.21; P = 0.032], BMI (OR = 0.93; 95% CI = 0.72-1.08; P = 0.006), hypertension (OR = 1.08; 95%CI = 1.02-1.26; P = 0.025) and APN (OR= 0.61; 95%CI = 0.43-0.88; P = 0.018) were independent factors of attenuated HRR in PCOS women. Meanwhile, multiple linear regression analysis showed only age (β=-0.26; 95%CI =-0.47- -0.03, P= 0.041) and hyperlipemia (β=-0.13; 95%CI =-0.27-0.08, P= 0.024) were closely associated with APN levels in PCOS women.Conclusions: Our findings suggested that decreased APN concentration was closely associated with HRR blunt in PCOS women. Further studies are needed to explore the underlying interactions between APN and autonomic nervous function.