Ankle muscle activity modulation during single-leg stance differs between children, young adults and seniors

Abstract

Purpose

Incomplete maturation and aging-induced declines of the neuromuscular system affect postural control both in children and older adults and lead to high fall rates. Age-specific comparisons of the modulation of ankle muscle activation and behavioral center of pressure (COP) indices during upright stance have been rarely conducted. The objective of the present study was to quantify aging effects on a neuromuscular level. Thus, surface electromyography (SEMG) modulation and co-activity of ankle muscles during single-leg standing was compared in healthy children, young adults and seniors.

Methods

Postural steadiness (velocity and mean sway frequency of COP), relative muscle activation (SEMG modulation) and co-activation of two ankle muscles (tibialis anterior, TA; soleus, SO) were examined during single-leg stance in 19 children [age, 9.7 (SD 0.5) years], 30 adults [23.3 (1.5) years] and 29 seniors [62.7 (6.1) years].

Results

Velocity of COP in medio-lateral and anterior–posterior directions, mean sway frequency in anterior–posterior direction, relative muscle activation (TA and SO) and co-activation revealed large age effects (P < 0.003, η _p² > 0.14). Post-hoc comparisons indicated higher COP velocities, anterior–posterior frequencies, relative SO activation and co-activation in children and seniors when compared with adults. Relative TA activation was higher in children and adults compared with seniors (P < 0.001).

Conclusions

Increased postural sway in children and seniors seems to be counteracted with higher TA/SO co-activity and SO modulation. However, TA modulation is higher in children and adults, whereas seniors' TA modulation capacity is diminished. An aging-induced decline of TA motor units might account for deteriorations of TA modulation in seniors.

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Kv4 channels to kisspeptin neurons: “Let's (not) go steady”

Abstract

Fertility in all mammals is ultimately controlled by a population of neurons in the ventral forebrain that produce the gonadotropin-releasing hormone (GnRH).

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Expression of Chemerin in the Synovial Fluid of Patients with Temporomandibular Joint Disorders

Summary

The synovial membrane and fluid are significantly involved in the pathogenesis of temporomandibular joint (TMJ) disorders. This study aimed to investigate the relation between levels of chemerin in the synovial fluid (SF) of patients with TMJ disorder and their relationship. Sixty samples of SF were obtained from patients with an internal derangement (ID) or osteoarthritis (OA). Chemerin in the SF was examined by enzyme-linked immunosorbent assay (ELISA). The results showed greater levels of chemerin in the SF of patients with OA than ID. While chemerin levels were positively correlated with pain scores, they were inversely correlated with MMO. Chemerin levels increased progressively as the disorder stage became more severe. The findings of this study suggest that chemerin in SF may play role as a predisposing factor and may represent a novel potential prognostic biochemical marker in the pathogenesis of TMJ disorders.

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An alternative technique to use the Trachway® for nasotracheal intubation.

An alternative technique to use the Trachway® for nasotracheal intubation.

J Clin Anesth. 2018 Jan 09;46:13-14

Authors: Lin CM, Hung KC

PMID: 29329070 [PubMed - as supplied by publisher]

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Human phenotypes caused by PIEZO1 mutations; one gene, two overlapping phenotypes?

Abstract

PIEZO1 is a large mechanosensitive ion channel protein. Diseases associated with PIEZO1 include autosomal recessive Generalised Lymphatic Dysplasia of Fotiou (GLDF) and autosomal dominant Dehydrated Hereditary Stomatocytosis with or without pseudohyperkalemia and/or perinatal oedema (DHS). The two disorders show overlapping features, fetal hydrops/perinatal oedema have been reported in both. Electrophysiological studies suggest opposite mechanisms of action, the mutations identified in GLDF patients cause a loss-of-function mechanism of disease and mutations in DHS patients cause gain-of-function. This raises the question, is the pathogenic disease mechanism behind the fetal oedema the same in the two phenotypes? In this symposium review, we will discuss the two conditions and highlight key questions that remain to be answered. For instance, the perinatal oedema often resolves soon after birth and we are still at a loss to understand why. Are there any mechanisms which could compensate for the faulty PIEZO1 in these patients? Are there physiological changes at birth that are less reliant on the function of PIEZO1? Thus, there is a clear need for further studies into the two disorders, in order to fully understand the role of PIEZO1 in health and disease.

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Mallory–Weiss syndrome diagnosed after tracheal extubation

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Vasoactive-inotropic score as a predictor of morbidity and mortality in adults after cardiac surgery with cardiopulmonary bypass

Abstract

Purpose

The vasoactive-inotropic score (VIS) is a scale showing the amount of vasoactive and inotropic support. Recently, it was suggested that the VIS after cardiac surgery predicts morbidity and mortality in infants. The purpose of this study was to evaluate the VIS at the end of surgery as a predictor of morbidity and mortality in adult cardiac surgery.

Methods

A retrospective cohort study of 129 adult cardiac surgery patients was performed at a university hospital. The primary outcome was termed "poor outcome", which was a composite of morbidity and mortality. The secondary outcomes were the duration of intensive care unit (ICU) stay and time to first extubation. Multivariate logistic regression analysis was performed to evaluate the association between the VIS and poor outcomes. A proportional hazards model was used to evaluate the duration of the ICU stay and time to first extubation.

Results

After adjusting for the EuroSCORE, preoperative ejection fraction, and bypass time, a high VIS at the end of surgery was associated with a poor outcome with an adjusted odds ratio of 4.87 (95% confidence interval 1.51–18.94; p = 0.007). After controlling for the EuroSCORE and bypass time, patients with a high VIS experienced longer ICU stay (hazard ratio 1.62; 95% confidence interval 1.10–2.39; p = 0.015) and needed longer ventilation (hazard ration 1.87; 95% confidence interval 1.28–2.74, p = 0.001).

Conclusions

The amount of cardiovascular support at the end of cardiac surgery may predict morbidity and mortality in adults.

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Factors Associated with Anxiety About Colonoscopy: The Preparation, the Procedure, and the Anticipated Findings

Abstract

Background

Previous research has assessed anxiety around colonoscopy procedures, but has not considered anxiety related to different aspects related to the colonoscopy process.

Aims

Before colonoscopy, we assessed anxiety about: bowel preparation, the procedure, and the anticipated results. We evaluated associations between patient characteristics and anxiety in each area.

Methods

An anonymous survey was distributed to patients immediately prior to their outpatient colonoscopy in six hospitals and two ambulatory care centers in Winnipeg, Canada. Anxiety was assessed using a visual analog scale. For each aspect, logistic regression models were used to explore associations between patient characteristics and high anxiety.

Results

A total of 1316 respondents completed the questions about anxiety (52% female, median age 56 years). Anxiety scores > 70 (high anxiety) were reported by 18% about bowel preparation, 29% about the procedure, and 28% about the procedure results. High anxiety about bowel preparation was associated with female sex, perceived unclear instructions, unfinished laxative, and no previous colonoscopies. High anxiety about the procedure was associated with female sex, no previous colonoscopies, and confusing instructions. High anxiety about the results was associated with symptoms as an indication for colonoscopy and instructions perceived as confusing.

Conclusions

Fewer people had high anxiety about preparation than about the procedure and findings of the procedure. There are unique predictors of anxiety about each colonoscopy aspect. Understanding the nuanced differences in aspects of anxiety may help to design strategies to reduce anxiety, leading to improved acceptance of the procedure, compliance with preparation instructions, and less discomfort with the procedure.

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Acute acetaminophen ingestion improves performance and muscle activation during maximal intermittent knee extensor exercise

Abstract

Aim

Acetaminophen is a commonly used medicine for pain relief and emerging evidence suggests that it may improve endurance exercise performance. This study investigated some of the physiological mechanisms by which acute acetaminophen ingestion might blunt muscle fatigue development.

Methods

Thirteen active males completed 60 × 3 s maximum voluntary contractions (MVC) of the knee extensors with each contraction separated by a 2 s passive recovery period. This protocol was completed 60 min after ingesting 1 g of maltodextrin (placebo) or 1 g of acetaminophen on two separate visits. Peripheral nerve stimulation was administered every 6th contraction for assessment of neuromuscular fatigue development, with the critical torque (CT), which reflects the maximal sustainable rate of oxidative metabolism, taken as the mean torque over the last 12 contractions. Surface electromyography was recorded continuously as a measure of muscle activation.

Results

Mean torque (61 ± 11 vs. 58 ± 14% pre-exercise MVC) and CT (44 ± 13 vs. 40 ± 15% pre-exercise MVC) were greater in the acetaminophen trial compared to placebo (both P < 0.05). Voluntary activation and potentiated twitch declined at a similar rate in both conditions (P > 0.05). However, the decline in electromyography amplitude was attenuated in the acetaminophen trial, with electromyography amplitude being greater compared to placebo from 210 s onwards (P < 0.05).

Conclusion

These findings indicate that acute acetaminophen ingestion might be ergogenic by increasing CT and preserving muscle activation during high-intensity exercise.

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Spectrum of bone marrow pathology and hematological abnormalities in methylmalonic acidemia

Patients with isolated methylmalonic acidemia (MMA) may present with a wide range of hematological complications including anemia, leukopenia, thrombocytopenia, and pancytopenia. However, there are very limited data on the development of hemophagocytosis or myelodysplasia in these patients. We report three patients with isolated MUT related MMA who presented with severe refractory pancytopenia during acute illness. Their bone marrow examination revealed a wide spectrum of pathology varying from bone marrow hypoplasia, hemophagocytosis to myelodysplasia with ring sideroblasts. We discuss their management and outcome. This report emphasizes the need for bone marrow examination in these patients with refractory or unexplained severe cytopenia, to confirm bone marrow pathology, and to rule out other diseases with similar clinical presentation for a better clinical outcome.

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