Search results for "Muscle"

Data from: Noninvasive assessment of respiratory muscle strength and activity in Myotonic dystrophy

2018

Objective To evaluate sensitivity/specificity of the maximum relaxation rate (MRR) of inspiratory muscles, amplitude of electromyographic activity of the sternocleidomastoid (SCM), scalene (SCA), parasternal (2ndIS) and rectus abdominis (RA) muscles; lung function and respiratory muscle strength in subjects with Myotonic dystrophy type 1 (DM1) compared with healthy subjects. Design and methods Quasi-experimental observational study with control group. MRR of inspiratory muscles, lung function and amplitude of the electromyographic activity of SCM, SCA, 2ndIS and RA muscles during maximum inspiratory pressure (PImax), maximum expiratory pressure (PEmax) and sniff nasal inspiratory pressure (…

Structure and Function of Desmosomes

2007

Desmosomes are prominent adhesion sites that are tightly associated with the cytoplasmic intermediate filament cytoskeleton providing mechanical stability in epithelia and also in several nonepithelial tissues such as cardiac muscle and meninges. They are unique in terms of ultrastructural appearance and molecular composition with cell type-specific variations. The dynamic assembly properties of desmosomes are important prerequisites for the acquisition and maintenance of tissue homeostasis. Disturbance of this equilibrium therefore not only compromises mechanical resilience but also affects many other tissue functions as becomes evident in various experimental scenarios and multiple diseas…

Hsp60 in Skeletal Muscle: From Molecular Anatomy to Pathophysiology

2019

The chaperoning system of an organism is composed of the entire set of chaperones, co-chaperones, and chaperone co-factors and their interactors and receptors. Its functions pertain typically to protein homeostasis but also to many other activities inside and outside cells. In the skeletal muscle, with its multi-molecular structures rich in proteins and their continuous rearrangements, the chaperoning system plays a crucial role. However, little is known about the details of the workings of the chaperoning system in skeletal muscle development and during exercise and disease. Molecular chaperones are surely involved in muscle formation and maintenance under physiologic conditions and under …

Truncation effects on muscular fatigue indexes based on M waves analysis

2012

International audience; In this paper, we investigate muscular fatigue. We propose a new fatigue index based on the continuous wavelet transform (CWT) and compare it with the standard fatigue indexes from literature. Fatigue indexes are all based on the electrical activity of muscles (electromyogram) acquired during an electrically stimulated contraction (ES). The stimulator and electromyogram system, which were presented in a previous work, allows real-time analysis. The extracted fatigue parameters are compared between each other and their sensitivity to noise is studied. The effect of truncation of M waves is then investigated, enlightening the robustness of the index obtained using CWT.

Multi axis representation and Euclidean distance of muscle fatigue indexes during evoked contractions

2014

International audience; In this article, we proposed a new representation of muscular fatigue during evoked muscle contractions based on fatigue indexes such as peak to peak amplitude, RMS of the M wave, mean and median frequency and fatigue index calculated from continuous wavelet transform (I CWT). These new representations of muscle fatigue using multi axis represented and Euclidean distance give better insights on changes in physiological characteristics during muscle fatigue. This technique provides a fatigue index using several muscle characteristics. The use of other kinds of fatigue characteristics as force could also be possible.

2019

Ankle plantar flexor muscles are active in the stance phase of walking to propel the body forward. Increasing walking speed requires increased plantar flexor excitation, frequently assessed using surface electromyography (EMG). Despite its popularity, validity of surface EMG applied on shank muscles is mostly unclear. Thus, we examined the agreement between surface and intramuscular EMG at a range of walking speeds. Ten participants walked overground at slow, preferred, fast, and maximum walking speeds (1.01 ± 0.13, 1.43 ± 0.19, 1.84 ± 0.23, and 2.20 ± 0.38 m s-1, respectively) while surface and fine-wire EMG activities of flexor hallucis longus (FHL), soleus (SOL), medial gastrocnemius (MG…

Concentric force enhancement during human movement

2001

In order to understand the possible mechanisms contributing to enhanced concentric performance in stretch-shortening cycle exercises in vivo the present study examined knee extension torque, electromyogram (EMG) activity and fascicle length of the vastus lateralis muscle in maximal and submaximal human movements. Maximal concentric knee extensions (120 degrees s(-1)) were done after pre-stretch and pre-isometric conditions by nine volunteers. During shortening at the knee angle of 115 degrees (180 degrees = extended) the knee extension torque was found to be greater in pre-stretch condition (272 vs. 248 N m, P < 0.05) although the torque level prior to shortening was smaller than in pre-iso…

Muscle ultrasonography and computed tomography in elderly trained and untrained women

1993

Ultrasonography (US) and computed tomography (CT) were compared in studying the associations between long-term physical training and quadriceps muscle mass and structure in female athletes and controls, aged 66-85 years. Muscle cross-sectional area (CSA) measured using US correlated highly with that measured using CT, but the latter technique yielded 30% higher values on average. The echo intensity of the fasciae and bone measured by US correlated positively with the mean radiological density and negatively with the relative proportion of fat obtained from CT. Low intramuscular echo intensity was accompanied by high muscle density and low relative proportion of fat. The athletes had larger …

New imaging procedures in thyroid-associated ophthalmopathy

1996

Lymphocytic and other mononuclear cell infiltrations of the retrobulbar space are observed in thyroid-associated ophthalmopathy (TAO). The identification of somatostatin receptors on lymphocytes has provided a rationale for receptor-imaging with the radiolabeled somatostatin analog Octreotide in TAO. Furthermore, previous investigations have shown that quantitative magnetic resonance imaging (MRI) allows non-invasive detection of acute inflammatory changes in extraocular muscles. Therefore, in patients with TAO and controls, scans of the orbits were obtained at 4h and 24h after i.v. injection of the radionuclide and orbital MRI was performed. Compared to controls, patients with TAO showed a…

Contribution of benzodiazepines in dental care of patients with special needs.

2019

Background Conscious sedation in dental treatment of patients with special needs (PNEs) has the purpose of controlling events such as anxiety and fear, as well as promoting muscle relaxation and mastery of uncoordinated movements. Benzodiazepines (BZDs) are among the most used drugs due to their anxiolytic, hypnotic and sedative properties. The objective of this investigation is to demonstrate a study on the contribution of conscious sedation with BZD in PNEs. Material and Methods The study included 40 PNEs, non-collaborators, submitted to conscious oral sedation with Midazolam (0.5 mg/kg) for dental treatment, receiving vital signs monitoring in the pre, trans and postoperative periods. Re…