Παρασκευή 3 Νοεμβρίου 2017

Effect of sufentanil on bispectral index in the elderly

Summary

We examined the impact of adding sufentanil during anaesthesia induction with propofol on bispectral index values in elderly patients (≥ 65 years). Patients were randomly assigned to receive a target-controlled sufentanil infusion (effect-site concentration of 0.3 ng.ml−1) or matching placebo, followed by a target-controlled propofol induction (initial effect-site concentration of 0.5 μg.ml−1; step-wise increase of 0.5 μg.ml−1) until loss of consciousness defined as an Observer's Assessment of Alertness/Sedation score < 2. Seventy-one patients (sufentanil 35, placebo 36) completed the study. Mean (SD) age was 72.3 (5.8) years; 41% were women. At loss of consciousness, mean (SD) bispectral index value was 75.0 (8.6) with sufentanil and 70.0 (8.0) with placebo; mean difference −5.0 (95% confidence interval −8.9 to −1.1), p = 0.013. Post-hoc analyses suggest that the difference was significant in men only (mean difference −7.3 (−11.8 to −2.6), p = 0.003). Sufentanil co-induction with propofol results in higher bispectral index values at loss of consciousness in elderly patients.



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Work stressors, depressive symptoms and sleep quality among US Navy members: a parallel process latent growth modelling approach across deployment

Summary

The present study examined whether work stressors contribute to sleep problems and depressive symptoms over the course of deployment (i.e. pre-deployment, post-deployment and 6-month reintegration) among US Navy members. Specifically, we examined whether depressive symptoms or sleep quality mediate the relationships between work stressors and these outcomes. Participants were 101 US Navy members who experienced an 8-month deployment after Operational Enduring Freedom/Operation Iraqi Freedom. Using piecewise latent growth models, we found that increased work stressors were linked to increased depressive symptoms and decreased sleep quality across all three deployment stages. Further, increases in work stressors from pre- to post-deployment contributed to poorer sleep quality post-deployment via increasing depressive symptoms. Moreover, sleep quality mediated the association between increases in work stressors and increases in depressive symptoms from pre- to post-deployment. These effects were maintained from post-deployment through the 6-month reintegration. Although preliminary, our results suggest that changes in work stressors may have small, but significant implications for both depressive symptoms and quality of sleep over time, and a bi-directional relationship persists between sleep quality and depression across deployment. Strategies that target both stress and sleep could address both precipitating and perpetuating factors that affect sleep and depressive symptoms.



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IJMS, Vol. 18, Pages 2320: Low Temperature Extends the Lifespan of Bursaphelenchus xylophilus through the cGMP Pathway

IJMS, Vol. 18, Pages 2320: Low Temperature Extends the Lifespan of Bursaphelenchus xylophilus through the cGMP Pathway

International Journal of Molecular Sciences doi: 10.3390/ijms18112320

Authors: Bowen Wang Ling Ma Feng Wang Buyong Wang Xin Hao Jiayao Xu Yan Ma

The causal agent of pine wilt disease, pine wood nematode (PWN) (Bursaphelenchus xylophilus), revealed extended lifespan at low temperature. To discover the molecular mechanism of this phenomenon, we attempted to study the molecular characterization, transcript abundance, and functions of three genes of the cyclic guanosine monophosphate (cGMP) pathway from B. xylophilus. Three cGMP pathway genes were identified from B. xylophilus. Bioinformatic software was utilized to analyze the characteristics of the three putative proteins. Function of the three genes in cold tolerance was studied with RNA interference (RNAi). The results showed that the deduced protein of Bx-DAF-11 has an adenylate and guanylate cyclase catalytic domain, indicating an ability to bind to extracellular ligands and synthesizing cGMP. Both Bx-TAX-2 and Bx-TAX-4 have cyclic nucleotide-binding domains and ion transport protein domains, illustrating that they are cGMP-gated ion channels. The transcript level of Bx-daf-11, Bx-tax-2, and Bx-tax-4 increased at low temperature. The survival rates of three gene silenced B. xylophilus revealed a significant decrease at low temperature. This study illustrated that the cGMP pathway plays a key role in low-temperature-induced lifespan extension in B. xylophilus.



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Numerical study of dynamic glottis and tidal breathing on respiratory sounds in a human upper airway model

Abstract

Background

Human snores are caused by vibrating anatomical structures in the upper airway. The glottis is a highly variable structure and a critical organ regulating inhaled flows. However, the effects of the glottis motion on airflow and breathing sound are not well understood, while static glottises have been implemented in most previous in silico studies. The objective of this study is to develop a computational acoustic model of human airways with a dynamic glottis and quantify the effects of glottis motion and tidal breathing on airflow and sound generation.

Methods

Large eddy simulation and FW-H models were adopted to compute airflows and respiratory sounds in an image-based mouth-lung model. User-defined functions were developed that governed the glottis kinematics. Varying breathing scenarios (static vs. dynamic glottis; constant vs. sinusoidal inhalations) were simulated to understand the effects of glottis motion and inhalation pattern on sound generation. Pressure distributions were measured in airway casts with different glottal openings for model validation purpose.

Results

Significant flow fluctuations were predicted in the upper airways at peak inhalation rates or during glottal constriction. The inhalation speed through the glottis was the predominating factor in the sound generation while the transient effects were less important. For all frequencies considered (20–2500 Hz), the static glottis substantially underestimated the intensity of the generated sounds, which was most pronounced in the range of 100–500 Hz. Adopting an equivalent steady flow rather than a tidal breathing further underestimated the sound intensity. An increase of 25 dB in average was observed for the life condition (sine-dynamic) compared to the idealized condition (constant-rigid) for the broadband frequencies, with the largest increase of approximately 40 dB at the frequency around 250 Hz.

Conclusion

Results show that a severely narrowing glottis during inhalation, as well as flow fluctuations in the downstream trachea, can generate audible sound levels.



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Corrigendum



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