Search results for " Muscle"

Murine muscle engineered from dermal precursors: an in vitro model for skeletal muscle generation, degeneration and fatty infiltration.

2013

Skeletal muscle can be engineered by converting dermal precursors into muscle progenitors and differentiated myocytes. However, the efficiency of muscle development remains relatively low and it is currently unclear if this is due to poor characterization of the myogenic precursors, the protocols used for cell differentiation, or a combination of both. In this study, we characterized myogenic precursors present in murine dermospheres, and evaluated mature myotubes grown in a novel three-dimensional culture system. After 5-7 days of differentiation, we observed isolated, twitching myotubes followed by spontaneous contractions of the entire tissue-engineered muscle construct on an extracellul…

What are the effects of the aging of the neuromuscular system on postural stability?

2015

International audience; Aging is frequently associated with a decreased postural stability, essentially after 60 years, leading to an increased risk of falling. In this article we propose to highlight the influence of the aging of the neuromuscular system on postural stability when standing upright. To maintain balance while standing upright, human needs to control the activity of ankle muscles and particularly the plantar flexors. During the aging process, the performance of these muscles are strongly altered. It is commonly observed large deficits in elderly people with history of falls. Some authors reported an inverse correlation between the amplitude of postural sway and the capacity o…

Cerebellar learning of bio-mechanical functions of extra-ocular muscles: modeling by artificial neural networks

2003

A control circuit is proposed to model the command of saccadic eye movements. Its wiring is deduced from a mathematical constraint, i.e. the necessity, for motor orders processing, to compute an approximate inverse function of the bio-mechanical function of the moving plant, here the bio-mechanics of the eye. This wiring is comparable to the anatomy of the cerebellar pathways. A predicting element, necessary for inversion and thus for movement accuracy, is modeled by an artificial neural network whose structure, deduced from physical constraints expressing the mechanics of the eye, is similar to the cell connectivity of the cerebellar cortex. Its functioning is set by supervised reinforceme…

Intermittent Theta-Burst Stimulation Over the Suprahyoid Muscles Motor Cortex Facilitates Increased Degree Centrality in Healthy Subjects

2020

Theta-burst stimulation (TBS), a variant of repetitive transcranial magnetic stimulation (rTMS), can potentially benefit the treatment of swallowing disorders. However, the after-effects of TBS on the swallowing motor cortex remain uncertain. The newly developed graph-based analysis of the centrality approach has been increasingly used to explore brain networks. The purpose of this study was to identify degree centrality (DC) alterations in the brain network after different TBS protocols were performed over the suprahyoid muscles motor cortex in healthy subjects. A total of 40 right-handed healthy subjects (mean age: 23.73 ± 2.57 years, range: 21–30, 20 females) were included in this study …

A single bout of endurance exercise induces αB-crystallin (CRYAB) modulation in cardiac muscle as it happens in oxidative skeletal muscle fibers

2018

CRYAB is a small Heat Shock Protein, expressed in various tissues such as skeletal and cardiac muscles, activated as phosphorylated CRYAB (pCRYAB) and involved in several pathophysiological processes. In mammals there are no reports to date on CRYAB activation following an acute endurance exercise, so the aim of my study was to explore in mouse cardiac tissue the pCRYAB levels as effect of this exercise at 0’, 15’ and 120’ of recovery. H2O2 - treated HL-1 cardiomyocytes have been utilized as in vitro model to identify the underlying molecular mechanism/s. Both in vivo and in vitro models showed no changes in CRYAB protein expression level but its phosphorylation state was significantly incr…

Procoagulant activities of skeletal muscle and cardiac myosins require both myosin protein and myosin-associated anionic phospholipids

2021

Proteins of Muscle and the Cytoskeleton

1994

The contractile elements of striated vertebrate skeletal muscle, the myofibrils, contain thin filaments, which are 6 nm in diameter and consist mainly of actin, and thicker myosin filaments with a diameter of 16 nm (Fig. 10.1). During muscle contraction, the filaments undergo a sliding movement relative to each other (sliding filament mechanism). This is brought about by the reversible formation of bridges between the myosin molecules and the actin filaments, which bind, change their conformation and then dissociate (bridge cycle). The required energy is supplied by the hydrolysis of ATP. The sliding distance (step size) per molecule of ATP hydrolysed is controversial; the most recent measu…

Polyunsaturated fatty acids in cultured cardiomyocytes : effect on physiology and beta-adrenoceptor function

1992

This study was carried out to investigate the influence of the membrane fatty acid composition on the basal electrical and contractile activities and the response to beta-adrenergic stimulation of rat cardiac muscle cells in culture. Cells were grown for 3 days in a conventional serum culture medium and then incubated for 24 h in synthetic media containing either n-6 or n-3 as the sole source of polyunsaturated fatty acids (PUFA). The n-6/n-3 ratio in the phospholipids was 0.9 in the n-3 cells and 13.1 in the n-6 cells compared with 6.3 in controls cells. Such modifications did not alter action potentials and the main parameters related to contraction, although shortening was slightly acce…

Bilaterally recorded multiple-unit activity of the cingulate cortex during head turning conditioning with unilateral medial forebrain bundle stimulat…

1993

Cats were conditioned to turn their heads using a tone conditioned stimulus (CS) and medial forebrain bundle stimulation (MFB) unconditioned stimulus (US). The CS+ was delivered to one ear at a time, in random order, followed by the US. A tone of a different frequency was used as a CS-. The cats learned to respond differentially to the CSs showing head movements of greater acceleration to the CS+ than CS- over sessions. Bilateral recordings of cingulate cortex multiple-unit activity showed increased response amplitudes over sessions and larger responses in the hemisphere ipsilateral to the US. Since ipsilateral multiple-unit responses did not differ for the CSs, the asymmetry was probably d…

The prognostic value of skeletal muscle index on clinical and survival outcomes after cytoreduction and HIPEC for peritoneal metastases from colorect…

2021

BACKGROUND Cytoreductive surgery (CRS) and hypertermic intraperitoneal chemotherapy (HIPEC) represent the most effective strategy to manage peritoneal metastases (PM). This systematic review and meta-analysis aimed to assess the impact of body composition on clinical outcomes in patients with PM. METHODS A systematic literature search was performed using Medline, Web of Science and EMBASE databases from inception to the 20st August 2020. Data were independently extracted by 3 authors. Newcastle-Ottawa Scale was used to assess quality and risk of bias of studies. Pooled analyses were performed using Mantel-Haenszel method to estimate overall effect size with mean differences or odd ratios (O…