Effects of water viscosity and tongue ingestion site on tongue pressure

Abstract

Objective

The purpose of this study was to help provide data to help to implement effective rehabilitation following surgery for oral cancer by comparing tongue pressure production for water and thickened water from the anterior and posterior parts of the tongue during swallowing.

Methods

Ten healthy volunteers (7 men, 3 women; age 27.6 ± 1.5 years) participated in the experiments. Tongue pressure during 3 ml water and 3 ml thickened water at the anterior and posterior tongue during swallowing were measured using a sensor sheet system with five measuring points on the hard palate. The sequential order of the points, maximal magnitude and duration of tongue pressure at each point were compared based on water viscosity and tongue ingestion site. There was a common pattern in the sequential order of tongue pressure generation among the two swallowing conditions.

Results

The maximal magnitude of tongue pressure was significantly higher when swallowing thickened water than when swallowing water at all points except for the anterior-median and mid-median part. Moreover, the pressure at all sites during posterior ingestions was significantly lower than that during anterior ingestion.

Conclusion

The present results provide mean values of tongue pressure during voluntarily triggered swallowing in anterior ingestion and posterior ingestion in young, healthy dentate individuals; these values can be clinically referenced for tongue pressure measurement in the evaluation of patients with dysphagia. The use of reference values may help streamline the diagnosis, treatment, and rehabilitation of dysphagia.

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The Psychophysiological Determinants of Pacing Behaviour and Performance During Prolonged Endurance Exercise: A Performance Level and Competition Outcome Comparison

Abstract

Introduction

A three-dimensional framework of centrally regulated and goal-directed exercise behaviour emphasised the integration of distinct sensory-discriminatory, affective-motivational and cognitive-evaluative dimensions that underpin perceived fatigability. This study aimed to capture the complex interdependencies and temporal dynamics in these processes, their interrelations with observed pacing behaviour, performance and biochemical variables as well as their performance level- and competition outcome-dependent variances.

Methods

Twenty-three cyclists of distinct performance level categories engaged in individual and head-to-head competition time trials against a performance-matched opponent. Sensory, affective and cognitive processes were respectively assessed with the constructs perceived physical strain and perceived mental strain, valence and felt arousal underpinning core affect and action crisis characterised by a shift from an implemental to a deliberative mindset.

Results

Performance level- and competition outcome-dependent variances and differential temporal dynamics in constructs were associated with alterations in pacing behaviour, performance and physiological disturbance. Perceived physical and mental strain were primarily associated with observed pacing behaviour as necessary to align planned behaviour with current physiological state. Valence and arousal were primarily associated with differential responses in performance regulation. The mindset shift associated with an action crisis was primarily associated with non-adaptive, psycho-neuro-endocrinological distress response.

Conclusion

The proposed constructs are interdependent in a nonlinear dynamic fashion, context dependent, constraint based, distinguishable by well-trained cyclists and interrelated with observed pacing behaviour, performance and physiological disturbance. The proposed framework provides a more comprehensive alternative to the Gestalt concept of perceived exertion and more completely accounts for centrally regulated and goal-directed exercise behaviour.

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A role for focal adhesion kinase in facilitating the contractile responses of murine gastric fundus smooth muscles

Abstract

Smooth muscle contraction involves regulating myosin light chain phosphorylation and dephosphorylation by myosin light chain kinase and myosin light chain phosphatase. CPI-17 and MYPT1 are crucial for regulating gastrointestinal smooth muscle contraction by inhibiting myosin light chain phosphatase. Integrin signalling involves the dynamic recruitment of several proteins, including FAK, to focal adhesions. FAK tyrosine kinase activation is involved in cell adhesion to the extracellular matrix via integrin signalling. FAK participates in linking the force generated by myofilament activation to the extracellular matrix and throughout the smooth muscle tissue. Here, we show that cholinergic stimulation activates FAK in gastric fundus smooth muscles. Electrical field stimulation in the presence of L-NAME and MRS2500 contracted gastric fundus smooth muscle strips and increased FAK Y397 phosphorylation (pY397). Atropine blocked the contractions and prevented the increase in pY397. The FAK inhibitor PF-431396 inhibited the contractions and the increase in pY397. PF-431396 also inhibited the EFS-induced increase in CPI-17 T38 phosphorylation, and reduced MYPT1 T696 and T853, and myosin light chain S19 phosphorylation. Ca²⁺ influx was unaffected by PF-431396. Nicardipine inhibited the contractions but had no effect on the increase in pY397. PDBu or calyculin A contracted gastric fundus smooth muscle strips Ca²⁺ independently and increased pY397. Our findings suggest that FAK is activated by mechanical forces during contraction, and reveal a novel role of FAK in the regulation of CPI-17 phosphorylation.

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The carotid chemoreceptor contributes to the elevated arterial stiffness and vasoconstrictor outflow in COPD

Abstract

COPD patients have increased central arterial stiffness and muscle sympathetic nervous activity (MSNA), both of which contribute to cardiovascular (CV) dysfunction and increased CV risk. Previous work suggests that COPD patients have elevated carotid chemoreceptor (CC) activity/sensitivity, which may contribute to the elevated MSNA and arterial stiffness. Accordingly, the effect of CC inhibition on central arterial stiffness, MSNA and CV function at rest in COPD patients was examined in a randomized placebo-controlled study. Thirteen mild-moderate COPD patients (FEV₁ predicted ± SD: 83 ± 19%) and 13 age- and risk-matched controls completed resting CV function measurements with either intravenous saline or I.V. dopamine (2 μg kg min⁻¹) while breathing normoxia or hyperoxia (100% O₂). On a separate day, a subset of COPD patients and controls completed MSNA measurements while breathing normoxia or hyperoxia. Arterial stiffness was determined by pulse-wave velocity (PWV) and MSNA was measured by microneurography. Brachial blood flow was determined using Doppler ultrasound, cardiac output was estimated by impedance cardiography, and vascular conductance was calculated as flow/mean arterial pressure (MAP). CC inhibition with dopamine decreased central and peripheral PWV, and MAP (P < 0.05) while increasing vascular conductance in COPD. No change in CV function was observed with dopamine in controls. CC inhibition with hyperoxia decreased peripheral PWV and MSNA (P < 0.05) in COPD, while no change was observed in controls. CC inhibition decreased PWV, MSNA and improved vascular conductance in COPD, suggesting that tonic CC activity is elevated at rest and contributes to the elevated arterial stiffness in COPD.

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Genetic engineering: Expanding the reach of Cas9

Genetic engineering: Expanding the reach of Cas9

Genetic engineering: Expanding the reach of Cas9, Published online: 12 March 2018; doi:10.1038/nrg.2018.15

Genetic engineering: Expanding the reach of Cas9

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Extreme delta - with or without brushes: a potential surrogate marker of disease activity in anti-NMDA-receptor encephalitis

Publication date: Available online 10 March 2018
Source:Clinical Neurophysiology
Author(s): Claude Steriade, Stephen Hantus, Ahsan N.V. Moosa, Alexander D. Rae-Grant
ObjectiveAnti-NMDA receptor encephalitis (NMDARE) may not respond to first line immunotherapy. Biomarkers to track disease course and guide escalation of immunotherapy are needed. We describe the evolution of EEG in four patients with NMDARE requiring prolonged intensive care.MethodsWithin a database of 121 patients with immune-mediated neurological disorders, ten with NMDARE were retrospectively identified. Four patients did not respond to first line immunotherapy. Continuous EEG was reviewed and correlated with clinical status and treatment.ResultsIntermittent polymorphic delta slowing was present in all patients. Generalized rhythmic delta occupied increasing proportion of the EEG as disease progressed, at times with superimposed beta. The institution of second line immunotherapy was followed by progressive decrease in rhythmic delta, predating clinical improvement. In one patient who did not respond to second line immunotherapy, rhythmic delta continued to occupy a majority of the recording. The extreme delta pattern was not seen in a comparison cohort of patients with autoimmune encephalitis without anti-NMDA-R antibodies.ConclusionsExtreme delta, with or without brushes, increases with progression of NMDARE, responds to escalation of immunotherapy, predating clinical improvement, and is likely specific to NMDA-R antibodies.SignificanceExtreme delta may be a surrogate marker of disease activity in NMDARE refractory to first line immunotherapy.



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Long Term Electroencephalography in Preterm Neonates: Safety and Quality of Electrode Types

Publication date: Available online 10 March 2018
Source:Clinical Neurophysiology
Author(s): Nathalie M. El Ters, Amit M. Mathur, Siddharth Jain, Zachary A. Vesoulis, John M. Zempel
ObjectivesThe objective of this study was to compare gold cup and hydrogel electrodes for frequency of electrode replacement, longevity of the original electrodes after initial placement, recording quality, and skin safety issues in long-term EEG studies in preterm neonates.MethodsWe performed a prospective trial with newborns born at ≥23 weeks and ≤30 weeks of gestational age (GA). Two mirror image EEG electrode arrays were utilized on consecutive subjects, wheregold cup electrodes alternated with hydrogel electrodes.ResultsOur sample included 50 neonates with meanGA of 27 (±1) weeks. The mean recording time was 84 (±15) hours. No difference was present in the frequency of replacement of either type across the total recording time (p=0.8). We collected the time at which electrodes were first replaced, and found that hydrogel electrodes showed a longer uninterrupted recording time of 28(±2) hours vs. 20(±2) hours for gold cup electrodes (p=0.01). Recording quality was similar in either type (p=0.2). None of the patients experienced significant skin irritation from a discrete electrode.ConclusionLong-term EEG studies can be performed with either gold cup or hydrogel electrodes, validating the safety and quality of both electrode types.SignificanceHydrogel electrodes are a reasonable alternative for use in long-term EEG studies in preterm neonates.



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