Search results for "Myofibril"

Morphology of experimentally denervated and reinnervated rat facial muscle I. Histochemical and histological findings

1994

The morphological changes in rat facial muscles were evaluated after permanent denervation and were compared with findings after immediate reinnervation. Thirty rats underwent transection of the left and right facial nerves immediately followed by hypoglossal-facial nerve anastomosis on the right side (muscular reinnervation) and removal of 8-10 mm of the facial plexus on the left side (permanent muscular denervation). Levator labii muscle samples of both sides were collected sequentially at 2, 6, 7, 10, 20, and 24 weeks after surgery and submitted to routine histological and enzyme histochemical staining procedures. In normal levator labii muscles a typical "chessboard" pattern was found, …

Neonatal form of nemaline myopathy, muscle immaturity, and a microvascular injury.

1990

An infant with a neonatal form of nemaline myopathy showed ultrastructural features of muscle immaturity. Immaturity was characterized by an abnormal presence of myotubes, as well as cells in clusters within a common basement membrane and a great number of satellite cells adhering to very small muscle fibers. In addition, degenerative changes and a severe microvascular lesion were observed. The pathologic findings in the muscle of this patient were those of neonatal nemaline myopathy complicating severe microvascular injury, possibly induced by an unknown toxic agent. ( J Child Neurol 1990;5:122-126).

Neuromuscular electrical stimulation training induces atypical adaptations of the human skeletal muscle phenotype: a functional and proteomic analysis

2011

Import JabRef | WosArea Physiology; Sport Sciences; International audience; The aim of the present study was to define the chronic effects of neuromuscular electrical stimulation (NMES) on the neuromuscular properties of human skeletal muscle. Eight young healthy male subjects were subjected to 25 sessions of isometric NMES of the quadriceps muscle over an 8-wk period. Needle biopsies were taken from the vastus lateralis muscle before and after training. The training status, myosin heavy chain (MHC) isoform distribution, and global protein pattern, as assessed by proteomic analysis, widely varied among subjects at baseline and prompted the identification of two subgroups: an "active" (ACT) …

Effects of Tributyltin(IV) Chloride Exposure on Larvae ofCiona intestinalis (Urochordata): An Ultrastructural Study

1996

The effects of tributyltin(IV) chloride (TBT chloride) have been tested on embryos of the ascidian Ciona intestinalis, at two different stages of development: (1) before hatching (coiled larval stage) and (2) 2 h after hatching (swimming larval stage). In vivo observations carried out with a light microscope showed that embryos at the coiled larval stage did not hatch following exposure to TBT chloride. Severe anomalies in the swimming larva, mainly concerning the morphology of the tail, which appeared twisted and squatter than in the controls, were observed. Such anomalies were also found at a functional level, i.e. contractile movements were poor so that the larvae appeared motionless. Ul…

2020

Skeletal muscle atrophy is characterized by a decrease in muscle fiber size as a result of a decreased protein synthesis, which leads to degradation of contractile muscle fibers. It can occur after denervation and immobilization, and glucocorticoids (GCs) may also increase protein breakdown contributing to the loss of muscle mass and myofibrillar proteins. GCs are already used in vitro to induce atrophic conditions, but until now no studies with primary human skeletal muscle existed. Therefore, this study deals with the effects of the GC dexamethasone (dex) on primary human myoblasts and myotubes. After incubation with 1, 10, and 100 µM dex for 48 and 72 h, gene and protein expression analy…

Primary desminopathies.

2007

•  Introduction •  Desmin is an essential component of the extrasarcomeric cytoskeleton in striated muscle cells •  Distal myopathy,cardiac arrhythmias,cardiomyopathy:classical criteria of primary desminopathies •  Sub-sarcolemmal and cytoplasmic desmin-positive protein aggregates:the morphological hallmark of primary and secondary desminopathies •  The spectrum of pathogenic desmin gene mutations •  The molecular pathogenesis of primary desminopathies: some answers gained,but even more questions raised •  Diagnostic work-up to distinguish primary from secondary desminopathies •  Treatment and clinical management of primary desminopathy patients Abstract Mutations of the human desmin gene o…

Celiac disease and selective immunoglobulin A deficiency

1997

Selective IgA deficiency was observed in 12 of 688 (1.7%) patients with celiac disease who were clinically undistinguishable from patients with celiac disease with normal IgA levels. This high prevalence of IgA deficiency in patients with celiac disease makes serum IgA assay advisable when screening for celiac disease is performed by measurement of antigliadin antibodies or anti-IgA endomysium antibodies. Similarly, subjects with IgA deficiency should be considered at risk of celiac disease.

In-frame deletion in the seventh immunoglobulin-like repeat of filamin C in a family with myofibrillar myopathy.

2009

Myofibrillar myopathies (MFMs) are an expanding and increasingly recognized group of neuromuscular disorders caused by mutations in DES, CRYAB, MYOT, and ZASP. The latest gene to be associated with MFM was FLNC; a p.W2710X mutation in the 24th immunoglobulin-like repeat of filamin C was shown to be the cause of a distinct type of MFM in several German families. We studied an International cohort of 46 patients from 39 families with clinically and myopathologically confirmed MFM, in which DES, CRYAB, MYOT, and ZASP mutations have been excluded. In patients from an unrelated family a 12-nucleotide deletion (c.2997_3008del) in FLNC resulting in a predicted in-frame four-residue deletion (p.Val…

Endurance training decreases the alkaline proteolytic activity in mouse skeletal muscles.

1984

Alkaline and myofibrillar protease activities of rectus femoris, soleus, and tibialis anterior muscles and the pooled sample of gastrocnemius and plantaris muscles were analyzed in male NMRI-mice during a running-training program of 3, 10, or 20 daily 1-h sessions. The activity of citrate synthase increased during the endurance training, reflecting the increased oxidative capacity of skeletal muscles. The activities of alkaline and myofibrillar proteases continually decreased in the course of the training program in all muscles studied. Instead, the activity of beta-glucuronidase (a marker of lysosomal hydrolases) increased in all muscles. The highest activities were observed at the beginni…

Relationships between muscle fibre characteristics and physical performance capacity in trained athletic boys

1991

The relationships between muscle fibre characteristics and the physical performance capacity of trained athletic boys (aged 11-13 years) were studied over 2 days. The subjects were divided into two groups according to muscle fibre distribution. The 'fast' group (FG) comprised 10 subjects (sprinters, weightlifters, tennis players) with more than 50% fast-twitch fibres (type II), and the 'slow' group (SG) comprised 8 subjects (endurance runners, tennis players, one weightlifter) with more than 50% slow-twitch fibres (type I) in their vastus lateralis muscle. The 'fast' group had 59.2 +/- 6.3% and the 'slow' group had 39.4 +/- 9.8% type II fibres. Other clear differences (P less than 0.05-0.01…