Δευτέρα, 4 Φεβρουαρίου 2019

Beckwith–Wiedemann syndrome in diverse populations

Beckwith–Wiedemann syndrome (BWS) is the most common epigenetic overgrowth disorder and presents with patients affected by a variety of clinical features. Although genotype–phenotype correlations have been demonstrated in BWS and although BWS has been reported to occur equally among racial and ethnic backgrounds, no study to date has evaluated the frequency of findings in different backgrounds. In this study, we evaluated the incidence of clinical features and molecular diagnoses among patients with BWS in Caucasian, Mixed, and non‐Caucasian groups. These results suggest that clinical features and molecular diagnoses differ between race/ethnicity groups and raise the possibility of race and ethnicity effects on genotype–phenotype correlations in BWS.



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Isolated vocal cord paralysis in two siblings with compound heterozygous variants in MUSK: Expanding the phenotypic spectrum

The congenital myasthenic syndromes (CMS) are a heterogeneous group of disorders caused by perturbations in signal transduction at the neuromuscular junction. Defects in muscle, skeletal, receptor tyrosine kinase (MuSK) cause two distinct phenotypes: fetal akinesia with multiple congenital anomalies (Fetal akinesia deformation sequence [MIM:208150]) and early onset congenital myasthenia (myasthenic syndrome, congenital, 9, associated with acetylcholine receptor deficiency [MIM:616325]). Myasthenia due to MuSK deficiency has variable clinical features, ranging from a milder presentation of isolated late‐onset proximal muscle weakness; to a severe presentation of prenatal‐onset diffuse weakness, ophthalmoplegia, respiratory failure, and vocal cord paralysis (VCP). Here, we propose to expand the phenotypic spectrum for MuSK deficiency to include isolated VCP with the absence of other classical myasthenic symptoms. We evaluated two brothers who presented in the neonatal period with respiratory failure secondary to isolated VCP. Research‐based exome sequencing revealed biallelic likely pathogenic variants in MUSK (MIM:601296). Both children had normal gross motor and fine motor development. One brother had speech delay, likely due to a combination of tracheostomy status and ankyloglossia. This case report suggests that CMS should be on the differential diagnosis for familial recurrence of VCP.



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Principles of Motor Learning to Support Neuroplasticity After ACL Injury: Implications for Optimizing Performance and Reducing Risk of Second ACL Injury

Abstract

Athletes who wish to resume high-level activities after an injury to the anterior cruciate ligament (ACL) are often advised to undergo surgical reconstruction. Nevertheless, ACL reconstruction (ACLR) does not equate to normal function of the knee or reduced risk of subsequent injuries. In fact, recent evidence has shown that only around half of post-ACLR patients can expect to return to competitive level of sports. A rising concern is the high rate of second ACL injuries, particularly in young athletes, with up to 20% of those returning to sport in the first year from surgery experiencing a second ACL rupture. Aside from the increased risk of second injury, patients after ACLR have an increased risk of developing early onset of osteoarthritis. Given the recent findings, it is imperative that rehabilitation after ACLR is scrutinized so the second injury preventative strategies can be optimized. Unfortunately, current ACLR rehabilitation programs may not be optimally effective in addressing deficits related to the initial injury and the subsequent surgical intervention. Motor learning to (re-)acquire motor skills and neuroplastic capacities are not sufficiently incorporated during traditional rehabilitation, attesting to the high re-injury rates. The purpose of this article is to present novel clinically integrated motor learning principles to support neuroplasticity that can improve patient functional performance and reduce the risk of second ACL injury. The following key concepts to enhance rehabilitation and prepare the patient for re-integration to sports after an ACL injury that is as safe as possible are presented: (1) external focus of attention, (2) implicit learning, (3) differential learning, (4) self-controlled learning and contextual interference. The novel motor learning principles presented in this manuscript may optimize future rehabilitation programs to reduce second ACL injury risk and early development of osteoarthritis by targeting changes in neural networks.



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Effects of Catheterization on Artery Function and Health: When Should Patients Start Exercising Following Their Coronary Intervention?

Abstract

Coronary artery disease (CAD) is a leading cause of death worldwide, and percutaneous transluminal coronary angiography (PTCA) and/or percutaneous coronary intervention (PCI; angioplasty) are commonly used to diagnose and/or treat the obstructed coronaries. Exercise-based rehabilitation is recommended for all CAD patients; however, most guidelines do not specify when exercise training should commence following PTCA and/or PCI. Catheterization can result in arterial dysfunction and acute injury, and given the fact that exercise, particularly at higher intensities, is associated with elevated inflammatory and oxidative stress, endothelial dysfunction and a pro-thrombotic milieu, performing exercise post-PTCA/PCI may transiently elevate the risk of cardiac events. This review aims to summarize extant literature relating to the impacts of coronary interventions on arterial function, including the time-course of recovery and the potential deleterious and/or beneficial impacts of acute versus long-term exercise. The current literature suggests that arterial dysfunction induced by catheterization recovers 4–12 weeks following catheterization. This review proposes that a period of relative arterial vulnerability may exist and exercise during this period may contribute to elevated event susceptibility. We therefore suggest that CAD patients start an exercise training programme between 2 and 4 weeks post-PCI, recognizing that the literature suggest there is a 'grey area' for functional recovery between 2 and 12 weeks post-catheterization. The timing of exercise onset should take into consideration the individual characteristics of patients (age, severity of disease, comorbidities) and the intensity, frequency and duration of the exercise prescription.



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Turning Observed Founder Alleles into Expected Relationships in an Intercross Population

Pedigree-derived relationships for individuals from an intercross of several lines cannot easily account for the segregation variance that is mainly caused by loci with alternative alleles fixed in different lines. However, when all founders are genotyped for a large number of markers, such relationships can be derived for descendants as expected genomic relationships conditional on the observed founder allele frequencies. A tabular method was derived in detail for autosomes and the X chromosome. As a case study, we analyzed litter size and body weights at three different ages in an advanced mouse intercross (29 generations, total pedigree size 19,266) between a line selected for high litter size (FL1) and a highly inbred control line (DUKsi). Approximately 60% of the total genetic variance was due to segregation variance. Estimated heritability values were 0.20 (0.03), 0.34 (0.04), 0.23 (0.03), 0.41 (0.03) and 0.46 (0.02) for litter size, litter weight and body weight at ages of 21, 42 and 63 days, respectively (standard errors in brackets). These values were between 12% and 65% higher than observed in analyses that treated founders as unrelated. Fields of applications include experimental populations (selection experiments or advanced intercross lines) with a limited number of founders, which can be genotyped at a reasonable cost. In principle any number of founder lines can be treated. Additional genotypes from individuals in later generations can be combined into a joint relationship matrix by capitalizing on previously published approaches.



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Spotting malignancies from gastric endoscopic images using deep learning

Abstract

Background

Gastric cancer is a common kind of malignancies, with yearly occurrences exceeding one million worldwide in 2017. Typically, ulcerous and cancerous tissues develop abnormal morphologies through courses of progression. Endoscopy is a routinely adopted means for examination of gastrointestinal tract for malignancy. Early and timely detection of malignancy closely correlate with good prognosis. Repeated presentation of similar frames from gastrointestinal tract endoscopy often weakens attention for practitioners to result in true patients missed out to incur higher medical cost and unnecessary morbidity. Highly needed is an automatic means for spotting visual abnormality and prompts for attention for medical staff for more thorough examination.

Methods

We conduct classification of benign ulcer and cancer for gastrointestinal endoscopic color images using deep neural network and transfer-learning approach. Using clinical data gathered from Gil Hospital, we built a dataset comprised of 200 normal, 367 cancer, and 220 ulcer cases, and applied the inception, ResNet, and VGGNet models pretrained on ImageNet. Three classes were defined—normal, benign ulcer, and cancer, and three separate binary classifiers were built—those for normal vs cancer, normal vs ulcer, and cancer vs ulcer for the corresponding classification tasks. For each task, considering inherent randomness entailed in the deep learning process, we performed data partitioning and model building experiments 100 times and averaged the performance values.

Results

Areas under curves of respective receiver operating characteristics were 0.95, 0.97, and 0.85 for the three classifiers. The ResNet showed the highest level of performance. The cases involving normal, i.e., normal vs ulcer and normal vs cancer resulted in accuracies above 90%. The case of ulcer vs cancer classification resulted in a lower accuracy of 77.1%, possibly due to smaller difference in appearance than those cases involving normal.

Conclusions

The overall level of performance of the proposed method was very promising to encourage applications in clinical environments. Automatic classification using deep learning technique as proposed can be used to complement manual inspection efforts for practitioners to minimize dangers of missed out positives resulting from repetitive sequence of endoscopic frames and weakening attentions.



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Robotic gastrectomy versus laparoscopic gastrectomy for gastric cancer: meta-analysis and trial sequential analysis of prospective observational studies

Abstract

Background

To evaluate short- and long-term outcomes of robotic gastrectomy (RG) in patients with gastric cancer to determine whether RG is an acceptable alternative to laparoscopic gastrectomy (LG).

Methods

PubMed, Embase, the Cochrane Library, and Chinese Biomedical Database were searched for prospective observational studies (POSs) comparing RG with LG for gastric cancer until October 2017. We compared short-term and long-term outcomes using systematic review with meta-analysis and trial sequential analysis (TSA).

Results

Sixteen POSs including 4576 patients were included in the meta-analyses. Compared with LG, RG had longer operative time (MD 57.98 min, P < 0.00001), lesser blood loss (MD − 23.71 ml, P = 0.005), and shorter time to first post-operative flatulence (MD − 0.14 days, P = 0.03). No significant difference was found in terms of the number of harvested lymph nodes, complications, reoperation, mortality, open conversion, proximal resection margin, and distal resection margin. The meta-analyses of complications, overall survival, and disease-free survival did not yield any sign of statistically significant difference between the two treatments, and the cumulative Z-curve crossed neither the traditional boundary nor the trial sequential monitoring boundary, suggesting the lack of firm evidence. TSA demonstrated that the cumulative Z-curve crossed either the traditional boundary or the trial sequential monitoring boundary on blood loss and operative time.

Conclusions

The present study demonstrates that RG is as acceptable as LG in terms of short- and long-term outcomes. The TSA demonstrated that further studies are not needed to evaluate the operative time and blood loss differences between these techniques.



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A missense variant in the titin gene in Doberman pinscher dogs with familial dilated cardiomyopathy and sudden cardiac death

Abstract

The dog provides a large animal model of familial dilated cardiomyopathy for the study of important aspects of this common familial cardiovascular disease. We have previously demonstrated a form of canine dilated cardiomyopathy in the Doberman pinscher breed that is inherited as an autosomal dominant trait and is associated with a splice site variant in the pyruvate dehydrogenase kinase 4 (PDK4) gene, however, genetic heterogeneity exists in this species as well and not all affected dogs have the PDK4 variant. Whole genome sequencing of a family of Doberman pinchers with dilated cardiomyopathy and sudden cardiac death without the PDK4 variant was performed. A pathologic missense variant in the titin gene located in an immunoglobulin-like domain in the I-band spanning region of the molecule was identified and was highly associated with the disease (p < 0.0001). We demonstrate here the identification of a variant in the titin gene highly associated with the disease in this spontaneous canine model of dilated cardiomyopathy. This large animal model of familial dilated cardiomyopathy shares many similarities with the human disease including mode of inheritance, clinical presentation, genetic heterogeneity and a pathologic variant in the titin gene. The dog is an excellent model to improve our understanding of the genotypic phenotypic relationships, penetrance, expression and the pathophysiology of variants in the titin gene.



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Does an increase in energy return and/or longitudinal bending stiffness shoe features reduce the energetic cost of running?

Abstract

Purpose

This study focused on the effects of shoe energy return and shoe longitudinal bending stiffness on the energetic cost and biomechanics of running.

Methods

The energetic cost of running and biomechanical variables altering running economy (ground contact times, stride frequency, vertical and leg stiffness, ground reaction force impulses, alignment between the resultant ground reaction force and the leg) were measured for nineteen male recreational runners. Participants ran overground under their ventilatory anaerobic threshold (10.8 ± 1.1 km h−1 on average) using four shoe prototypes with features combining low or high magnitudes of energy return and longitudinal bending stiffness.

Results

Neither the energy return, nor the longitudinal bending stiffness, or the interaction of these shoe features altered the energetic cost of running. High energy return shoes induced significant increased ground contact time from 274.5 ± 18.3 to 277.1 ± 18.7 ms, and significant decreased stride frequency from 1.34 ± 0.05 to 1.33 ± 0.05 Hz. High bending stiffness shoes induced significant increased ground contact time from 273.8 ± 18.2 to 277.9 ± 18.7 ms, significant increased vertical stiffness from 23.2 ± 3.4 to 23.8 ± 3.0 kN m−1, and significant decreased net vertical impulse from 245.4 ± 17.2 to 241.7 ± 17.5 BW ms.

Conclusions

Increased energy return and longitudinal bending stiffness induced subtle changes in the running biomechanics, but did not induce any decrease in the energetic cost of running.



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Cardiovascular, muscular, and skeletal adaptations to recreational team handball training: a randomized controlled trial with young adult untrained men

Abstract

Purpose

The prevalence of lifestyle diseases has escalated, and effective exercise training programmes are warranted. This study tested the hypothesis that regular participation in small-sided team handball training could provide beneficial health effects on cardiovascular, skeletal, and muscular parameters in young adult untrained men.

Method

Twenty-six untrained 20–30-year-old men were randomly allocated to either a team handball training group (HG; n = 14), which completed 1.9 ± 0.3 training sessions per week over 12 weeks, or an inactive control group (CG; n = 12). Physiological training adaptations were assessed pre- and post interventions by DXA scans, blood samples, muscle biopsies, and physical tests.

Results

The average heart rate during training was equivalent to 84 ± 4% of maximal heart rate. Compared to CG, HG displayed significant increases in VO2max (11 ± 6%), proximal femur bone mineral density (2 ± 1%), whole-body bone mineral content (2 ± 1%), intermittent endurance performance (32 ± 16%), incremental treadmill test performance (16 ± 7%) and muscle citrate synthase activity (22 ± 28%) as well as decreases in total fat mass (7 ± 7%) and total fat percentage (6 ± 7%) (all p < 0.05). There were no significant changes in muscle mass, blood pressure, resting heart rate, muscle hydroxyl-acyl-dehydrogenase activity, or blood lipids (all p > 0.05).

Conclusion

Participation in regular recreational team handball training was associated with positive cardiovascular, skeletal, and muscular adaptations, including increased maximal oxygen uptake, increased muscle enzymatic activity, and improved bone mineralization as well as lower fat percentage. These findings suggest that recreational team handball training may be an effective health-promoting activity for young adult men.



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Flexibility in joint coordination remains unaffected by force and balance demands in young and old adults during simple sit-to-stand tasks

Abstract

Purpose

We examined the possibility that old adults use flexibility in joint coordination as a compensatory mechanism for the age-related decline in muscle strength when performing the sit-to-stand (STS) task repeatedly under high force and balance demands.

Method

Young (n = 14, 22.4 ± 2.1) and old (n = 12, 70 ± 3.2) healthy adults performed repeated STSs under high and low force and balance demands. The balance demand was manipulated by reducing the base of support and the force demand by increasing body weight with a weight vest. Uncontrolled manifold analysis was used to quantify age differences in motor flexibility.

Results

While there were age-typical differences in kinematic STS strategies, flexibility in joint coordination was independent of age and task difficulty during repeated STSs.

Discussion

That simple manipulations of force and balance demands did not affect flexibility in joint coordination in old and young adults suggests that motor flexibility acts as a compensatory mechanism only at the limits of available muscle strength and balance abilities during STS movements. Intervention studies should identify how changes in specific neuromuscular functions affect flexibility in joint coordination during activities of daily living such as STS.



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Pulmonary and respiratory muscle function in response to 10 marathons in 10 days

Abstract

Purpose

Marathon and ultramarathon provoke respiratory muscle fatigue and pulmonary dysfunction; nevertheless, it is unknown how the respiratory system responds to multiple, consecutive days of endurance exercise.

Methods

Nine trained individuals (six male) contested 10 marathons in 10 consecutive days. Respiratory muscle strength (maximum static inspiratory and expiratory mouth-pressures), pulmonary function (spirometry), perceptual ratings of respiratory muscle soreness (Visual Analogue Scale), breathlessness (dyspnea, modified Borg CR10 scale), and symptoms of Upper Respiratory Tract Infection (URTI), were assessed before and after marathons on days 1, 4, 7, and 10.

Results

Group mean time for 10 marathons was 276 ± 35 min. Relative to pre-challenge baseline (159 ± 32 cmH2O), MEP was reduced after day 1 (136 ± 31 cmH2O, p = 0.017), day 7 (138 ± 42 cmH2O, p = 0.035), and day 10 (130 ± 41 cmH2O, p = 0.008). There was no change in pre-marathon MEP across days 1, 4, 7, or 10 (p > 0.05). Pre-marathon forced vital capacity was significantly diminished at day 4 (4.74 ± 1.09 versus 4.56 ± 1.09 L, p = 0.035), remaining below baseline at day 7 (p = 0.045) and day 10 (p = 0.015). There were no changes in FEV1, FEV1/FVC, PEF, MIP, or respiratory perceptions during the course of the challenge (p > 0.05). In the 15-day post-challenge period, 5/9 (56%) runners reported symptoms of URTI, relative to 1/9 (11%) pre-challenge.

Conclusions

Single-stage marathon provokes acute expiratory muscle fatigue which may have implications for health and/or performance, but 10 consecutive days of marathon running does not elicit cumulative (chronic) changes in respiratory function or perceptions of dyspnea. These data allude to the robustness of the healthy respiratory system.



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Cardiovascular and autonomic responses to passive arm or leg movement in men and women

Abstract

Purpose

Women display an attenuated mechanoreflex during leg movement; however, sex differences in the response to arm movement are unknown.

Methods

Men (n = 12) and women (n = 10) performed passive arm or leg movement where either the right elbow or right knee was passively flexed/extended for 3 min at 30 times/min. Mean arterial pressure (MAP), cardiac output index (Qi), and heart rate (HR) were continuously measured and 1-min averages along with peak values were obtained. Heart rate variability was measured at baseline and throughout 3 min of passive movement.

Results

Men had a greater average HR (P = 0.006) and Qi (P = 0.05) responses to passive limb movement compared to women. Men also had a greater (P = 0.02) and faster (P = 0.04) peak Qi response compared to women. During arm movement, men exhibited a greater change of average MAP compared to both women (P = 0.002) and leg movement (P = 0.05). Movement of either limb in both sexes decreased low-frequency power (LF; P = 0.04), decreased low-frequency to high-frequency ratio (LF/HF; P = 0.03), and increased high-frequency power (HF; P = 0.01) of heart rate variability. Women had lower pulse wave velocity (P = 0.02), higher root mean square of the successive differences (RMSSD; P = 0.04), lower LF power (P = 0.04), higher HF power (P = 0.03), and higher cardiovagal baroreceptor sensitivity (P = 0.003) compared to men at all time points.

Conclusions

We have found sex- and limb-dependent responses where men exhibit higher blood pressure in response to passive arm movement compared to women and compared to leg movement.



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Local high-frequency vibration therapy following eccentric exercises reduces muscle soreness perception and posture alterations in elite athletes

Abstract

Purpose

Exercise-induced muscle damage produces painful sensations (delayed onset of muscle soreness, DOMS). DOMS causes compensatory postural adaptations, which in turn affect athletes' walking and running gait biomechanics. It is still debated whether the postural changes are due to impaired proprioception or pain perception. To disambiguate between these two contrasting hypotheses, we designed a study that tested post-exercise postural adjustments in two groups of athletes: a group who was administered a vibration therapy (VT), to attenuate pain perception, and a control group.

Methods

Thirty professional futsal players were tested on five different occasions: baseline, eccentric exercises (EE) session day, 24, 48 and 72 h after EE. Vibration therapy (120 Hz) was applied on legs muscles for 15 min in the experimental group, while no vibration was applied in the control group. The measurements included: isokinetic evaluation, stabilometric test, perceived soreness evaluation and serum levels of creatine kinase, and lactate dehydrogenase.

Results

48 h after EE, the control group showed changes in biomechanical parameters (antero-rotations of pelvis, p < 0.05). A substantial alteration in the hip kinematics was found, associated to a reduced contractile force (p < 0.01) and soreness perception. On the contrary, the VT group did not show any change in posture and pain perception. High-intensity VT decreases EE effects on muscle strength and DOMS.

Conclusions

DOMS significantly changes athletes' posture; but postural changes disappear following a VT therapy that decreases pain perception. It is concluded that soreness perception is the main cause of postural changes and that its effects can be counteracted using VT therapy.



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Effect of different knee flexion angles with a constant hip and knee torque on the muscle forces and neuromuscular activities of hamstrings and gluteus maximus muscles

Abstract

Purpose

This study examined the effect of different knee flexion angles with a constant hip and knee torque on the muscle force and neuromuscular activity of the hamstrings and gluteus maximus.

Methods

Twenty healthy males lay in prone position and held their lower limb with hip flexion at 45° and knee flexion at either 10° or 80°. At these angles, the hip and knee torques are identical. Under three load conditions: passive (referred to as Unloaded), active (Loaded), and active with 3-kg weight added to the shank (Loaded + 3 kg), the muscle stiffness (i.e., an indicator of muscle force) and neuromuscular activity of the hamstrings and gluteus maximus were measured using shear wave elastography and surface electromyography.

Results

The muscle stiffness and neuromuscular activity of the hamstrings and gluteus maximus increased significantly with the load. Muscle stiffness in the hamstrings was significantly lower at knee flexion of 80° than at 10° for Unloaded, but not for either Loaded or Loaded + 3 kg. The neuromuscular activity of the hamstrings was significantly greater at knee flexion of 80° than at 10° for both Loaded and Loaded + 3 kg. The muscle stiffness or neuromuscular activity of the gluteus maximus showed no significant differences between knee angles.

Conclusions

When the passive force in the hamstrings decreases with knee flexion, sufficient muscle force to maintain the hip and knee torques against an external load is generated by preferentially increasing the neuromuscular activity of the hamstrings, rather than increasing the synergetic muscle force.



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Effect of growth hormone treatment on energy expenditure and its relation to first-year growth response in children

Abstract

Purpose

The effects of growth hormone (GH) treatment on linear growth and body composition have been studied extensively. Little is known about the GH effect on energy expenditure (EE). The aim of this study was to investigate the effects of GH treatment on EE in children, and to study whether the changes in EE can predict the height gain after 1 year.

Methods

Total EE (TEE), basal metabolic rate (BMR), and physical activity level (PAL) measurements before and after 6 weeks of GH treatment were performed in 18 prepubertal children (5 girls, 13 boys) born small for gestational age (n = 14) or with growth hormone deficiency (n = 4) who were eligible for GH treatment. TEE was measured with the doubly labelled water method, BMR was measured with an open-circuit ventilated hood system, PAL was assessed using an accelerometer for movement registration and calculated (PAL = TEE/BMR), activity related EE (AEE) was calculated [AEE = (0.9 × TEE) − BMR]. Height measurements at start and after 1 year of GH treatment were analysed. This is a 1-year longitudinal intervention study, without a control group for comparison.

Results

BMR and TEE increased significantly (resp. 5% and 7%). Physical activity (counts/day), PAL, and AEE did not change. 11 out of 13 patients (85%) with an increased TEE after 6 weeks of GH treatment had a good first-year growth response (∆height SDS > 0.5).

Conclusions

GH treatment showed a positive effect on EE in prepubertal children after 6 weeks. No effect on physical activity was observed. The increase in TEE appeared to be valuable for the prediction of good first-year growth responders to GH treatment.



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Effects of a cyborg-type robot suit HAL on cardiopulmonary burden during exercise in normal subjects

Abstract

Background

The hybrid assistive limb (HAL) is the world's first cyborg-type robot suit that provides motion assistance to physically challenged patients. HAL is expected to expand the possibilities of exercise therapy for severe cardiac patients who have difficulty in moving on their own legs. As a first step, we examined whether or not the motion assistance provided by HAL during exercise could effectively reduce the cardiopulmonary burden in healthy subjects.

Methods

A total of ten healthy male adults (35 ± 12 years) underwent cardiopulmonary exercise testing (CPX) on a cycle ergometer with or without assistance from HAL. The CPX protocol consisted of four 3-min stages performed in a continuous sequence: rest, 0 W, 40 W, and 80 W. The heart rate (HR), blood pressure, oxygen uptake (VO2), minute ventilation (VE), and gas exchange ratio (R) were monitored during the CPX.

Results

At 0 W, the HR, VO2, and VE were significantly higher when HAL was used. At 80 W, however, the HR (107 ± 14 vs 114 ± 14 beats/min, p < 0.01), systolic blood pressure (141 ± 15 vs 155 ± 20 mmHg, p < 0.01), VO2 (17.6 ± 2.4 vs 19.0 ± 2.5 mL/min/kg, p < 0.05), and R (0.88 ± 0.04 vs 0.95 ± 0.09, p < 0.05) were significantly lower when HAL was used.

Conclusions

HAL has the potential to reduce cardiopulmonary burden during moderate-intensity exercise and can, therefore, be used as a support for exercise therapy. Further studies on cardiac patients are expected to contribute to the establishment of a new exercise therapy program using HAL.



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Effects of inspiratory muscle strength and inspiratory resistance on neck inspiratory muscle activation during controlled inspirations

New Findings

What is the central question of this study?

'What factors influence the onset and magnitude of activation of the neck inspiratory muscles during inspiration?'

What is the main finding and its importance?

Recruitment of the sternocleidomastoid and scalene muscles during inspiration, measured by means of surface electromyography (EMG), was strongly correlated with maximal inspiratory pressure (MIP). This result indicates that muscle recruitment depends on the capacity of an individual to generate inspiratory pressure. Surface measurements of neck inspiratory muscle EMG activity may compliment tests currently employed for the screening of respiratory‐related disease.

Abstract

The present study aimed to 1) examine the relationship between the recruitment onset of the neck inspiratory muscles and inspiratory muscle strength and 2) clarify the effect of inspiratory resistance on neck inspiratory muscle activation during inspiration at specific flow rates and to specific lung volumes. Inspiratory muscle strength, as indicated by maximal inspiratory pressure (MIP), and peak inspiratory flow rate (PFR) were measured in healthy participants. Subsequently, participants inspired at target inspiratory flow rates between 20% and 100% of PFR as closely as possible with and without artificial inspiratory resistance. Electromyographic activity (EMGRMS) of the sternocleidomastoid and scalene muscles was measured from surface electrodes at each target flow rate for each 10% increment of forced vital capacity (FVC) between 20 and 50% of FVC. Recruitment onset for each muscle was determined from %PFR–EMGRMS curves at each lung volume (%FVC). Finally, linear regression analyses were performed for MIP and recruitment onset for each muscle at each %FVC. Recruitment onset during inspiration without inspiratory resistance was strongly correlated with MIP (r > 0.60, P < 0.040). Specifically, a lower MIP was associated with earlier muscle recruitment (i.e. recruitment at a lower flow rate), especially for the sternocleidomastoid muscle (r > 0.75, P < 0.005). Recruitment of both neck inspiratory muscles at a given flow rate was also earlier when inspiratory resistance was added (P = 0.002). These results indicate that the recruitment and activation of the neck inspiratory muscles depends on both inspiratory muscle strength and inspiratory resistance.

This article is protected by copyright. All rights reserved



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Interoceptive accuracy, emotion recognition, and emotion regulation in preschool children

Publication date: Available online 4 February 2019

Source: International Journal of Psychophysiology

Author(s): Luca Schaan, André Schulz, Sevim Nuraydin, Cora Bergert, Annett Hilger, Hannah Rach, Tanja Hechler

Abstract

Little is known about the conscious experience of internal bodily sensations in preschool-aged children. Given that preschoolers are in the most rapid phase of brain development, and display profound emotional development, it was the aim of the present study to establish an adapted interoceptive accuracy paradigm and to investigate associations between sociodemographic (age, sex) and emotional variables with interoceptive accuracy. Forty-nine children (aged 4–6 years) completed the jumping jack paradigm, a heartbeat tracking paradigm, which includes a noninvasive physical perturbation via performing jumping jacks for 10 s. An interoceptive accuracy score was based on the comparison between self-reported and objectively recorded heart rate prior to and after completion of jumping jacks. Children also completed validated measures for emotion recognition and emotion regulation. Children's objectively recorded heart rate significantly increased after the JJP by 20 bpm on average. There was a positive relationship between reactivity on self-reported heart rate and objectively recorded heart rate increase. The derived scores for interoceptive accuracy increased with age, suggesting older children to report more self-reported heart rate change than objectively recorded, but were unrelated to children's sex or BMI. While emotion recognition and regulation significantly increased with age, the interoceptive accuracy score was unrelated to emotion recognition, but marginally associated to emotion regulation. Children with higher interoceptive accuracy score (i.e., self-reporting more heart rate change than objectively recorded) received lower emotion regulation score. The present study is the first to depict a novel behavioral paradigm to assess interoceptive accuracy in preschool-aged children.



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Dyshidrosis is associated with reduced amplitudes in electrically evoked pain-related potentials in women with Fabry disease

Publication date: Available online 4 February 2019

Source: Clinical Neurophysiology

Author(s): Gabriela Siedler, Ann-Kathrin Káhn, Frank Weidemann, Christoph Wanner, Claudia Sommer, Nurcan Üçeyler

Abstract
Objective

To investigate A-delta fiber conduction in mild to moderate Fabry disease (FD) patients using pain-related evoked potentials (PREP).

Methods

In this case-control study we prospectively investigated 58 patients with mild to moderate FD and compared data with those of healthy controls. Small fiber function (quantitative sensory testing, QST and sympathetic skin response, SSR), morphology (intraepidermal nerve fiber density, IENFD), and electrical conduction (PREP) were assessed and correlated with sweating as major autonomic function disturbed in FD. Patients were further stratified for gender, disease severity as reflected by renal and cardiac function, and genetics.

Results

An- or hypohidrosis (i.e. dyshidrosis) was reported by 7/32 (22%) women and 15/26 (58%) men with FD (p<0.01). QST showed small fiber impairment in female and male patients regardless of clinical symptoms, while SSR was obtained in all patients except one man with hypohidrosis. IENFD was reduced in 50% of FD patients, with no differences between groups with and without autonomic symptoms. However, PREP amplitudes were reduced independent of the stimulation site only in female patients with dyshidrosis (p<0.01). Genetics had no influence on PREP parameters.

Conclusion

A-delta fiber conduction investigated using PREP is impaired in mild to moderately affected female FD patients with clinical signs of hypohidrosis.

Significance

Small fiber assessment in FD is of diagnostic value already in mild to moderate stages of disease.



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Prolonged cortical silent period is related to poor fitness and fatigue, but not tumor necrosis factor, in Multiple Sclerosis

Publication date: Available online 4 February 2019

Source: Clinical Neurophysiology

Author(s): Arthur R. Chaves, Liam P. Kelly, Craig S. Moore, Mark Stefanelli, Michelle Ploughman

Abstract
Objective

Poor fitness among people with multiple sclerosis (MS) aggravates disease symptoms. Whether low fitness levels accompany brain functioning changes is unknown.

Methods

MS patients (n=82) completed a graded maximal exercise test, blood was drawn, and transcranial magnetic stimulation determined resting and active motor thresholds, motor evoked potential latency, and cortical silent period (CSP).

Results

Sixty-two percent of participants had fitness levels ranked below 10th percentile. Fitness was not associated with disability measured using the Expanded Disability Status Scale (EDSS). Regression analyses revealed that, cardiorespiratory fitness, when controlling for disease demographics, contributed 23.7% (p < 0.001) to the model explaining variance in CSP. Regression analysis using cardiorespiratory fitness and CSP as predictors showed that CSP alone explained 19.9% of variance in subjective fatigue (p = 0.002). Tumor necrosis factor was not associated with any variable.

Conclusion

Low fitness was associated with longer CSP in MS. Longer CSP was, in turn, related to greater MS fatigue.

Significance

MS patients had extremely low levels of cardiorespiratory fitness. Poor fitness predicted longer CSP, a marker of greater intracortical inhibition, which was linked to MS fatigue. Future research should examine whether aerobic training could shorten CSP and potentially lessen inhibition of cortical networks.



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β‐adrenergic‐mediated dynamic augmentation of sarcolemmal CaV1.2 clustering and cooperativity in ventricular myocytes

Abstract

Voltage‐dependent L‐type CaV1.2 channels play an indispensable role in cardiac excitation‐contraction (EC) coupling. Activation of the β‐adrenergic receptor (βAR)/cAMP/PKA signaling pathway leads to enhanced CaV1.2 activity resulting in increased Ca2+ influx into ventricular myocytes, and a positive inotropic response. CaV1.2 channels exhibit a clustered distribution along the T‐tubule sarcolemma of ventricular myocytes where nanometer proximity between channels permits Ca2+‐dependent cooperative gating behaviour mediated by dynamic, physical, allosteric interactions between adjacent channel C‐terminal tails. This amplifies Ca2+ influx and augments myocyte Ca2+ transient and contraction amplitudes. We investigated whether βAR signaling could alter CaV1.2 channel clustering to facilitate cooperative channel interactions and elevate Ca2+ influx in ventricular myocytes. Bimolecular fluorescence complementation experiments reveal that the βAR agonist, isoproterenol (ISO), promotes enhanced CaV1.2‐CaV1.2 physical interactions. Super‐resolution nanoscopy and dynamic channel tracking indicate that these interactions are expedited by enhanced spatial proximity between channels, resulting in the appearance of CaV1.2 'super‐clusters' along the z‐lines of ISO‐stimulated cardiomyocytes. The mechanism that leads to super‐cluster formation involves rapid, dynamic augmentation of sarcolemmal CaV1.2 channel abundance after ISO application. Optical and electrophysiological single channel recordings confirm that these newly inserted channels are functional and contribute to overt cooperative gating behaviour of CaV1.2 channels in ISO stimulated myocytes. Our study reveals a new facet of βAR‐mediated regulation of CaV1.2 channels in the heart and supports the novel concept that a pre‐synthesized pool of sub‐sarcolemmal CaV1.2 channel‐containing vesicles/endosomes reside in cardiomyocytes and can be mobilized to the sarcolemma to tune EC‐coupling to meet metabolic and/or hemodynamic demands.

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