Search results for "myofibril"
showing 10 items of 50 documents
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, …
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…
The early response of αB-crystallin to a single bout of aerobic exercise in mouse skeletal muscles depends upon fiber oxidative features
2019
Besides its substantial role in eye lens, αB-crystallin (HSPB5) retains fundamental function in striated muscle during physiological or pathological modifications. In this study, we aimed to analyse the cellular and molecular factors driving the functional response of HSPB5 protein in different muscles from mice subjected to an acute bout of non-damaging endurance exercise or in C2C12 myocytes upon exposure to pro-oxidant environment, chosen as “in vivo” and “in vitro” models of a physiological stressing conditions, respectively.To this end, red (GR) and white gastrocnemius (GW), as sources of slow-oxidative and fast-glycolytic/oxidative fibers, as well as the soleus (SOL), mainly composed …
Downregulation and Nuclear Relocation of MLP During the Progression of Right Ventricular Hypertrophy Induced by Chronic Pressure Overload
2000
Abstract The cardiac LIM domain protein MLP plays a crucial role in the architecture and mechanical function of cardiac myocytes. Mice lacking the MLP gene develop cardiac hypertrophy, dilated cardiopathy and heart failure. We investigated whether downregulation of MLP is induced by pressure overload and contributes to the physiopathology of cardiac hypertrophy and failure. We studied this mechanism in rat right ventricles submitted to pulmonary arterial hypertension, because it is known that this ventricle is very vulnerable to the deleterious effects of pressure overload. During the progression of cardiac hypertrophy to failure over a 31 days period there was a dramatic decrease by 50% of…
Absence of dysferlin alters myogenin expression and delays human muscle differentiation 'in vitro'
2006
Mutations in dysferlin cause a type of muscular dystrophy known as dysferlinopathy. Dysferlin may be involved in muscle repair and differentiation. We compared normal human skeletal muscle cultures expressing dysferlin with muscle cultures from dysferlinopathy patients. We quantified the fusion index of myoblasts as a measure of muscle development and conducted optic and electronic microscopy, immunofluorescence, Western blot, flow cytometry, and real-time PCR at different developmental stages. Short interference RNA was used to corroborate the results obtained in dysferlin-deficient cultures. A luciferase reporter assay was performed to study myogenin activity in dysferlin-deficient cultur…
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…
Novel slow-skeletal myosin (MYH7) mutation in the original myosin storage myopathy kindred
2006
Abstract Myosin storage myopathy (OMIM 608358), a congenital myopathy characterised by subsarcolemmal, hyaline-like accumulations of myosin in Type I muscle fibres, was first described by Cancilla and Colleagues in 1971 [Neurology 1971;21:579–585] in two siblings as ‘familial myopathy with probable lysis of myofibrils in type I muscle fibres'. Two mutations in the slow skeletal myosin heavy chain gene ( MYH7 ) have recently been associated with the disease in other families. We have identified a novel heterozygous Leu1793Pro mutation in MYH7 in DNA from paraffin sections of one of the original siblings. This historical molecular analysis confirms the original cases had myosin storage myopat…
Evidence of Transient IgA Anti-Endomysial Antibody Positivity in a Patient with Graves’ Disease
1999
<i>Background:</i> Anti-endomysial antibodies (EmA) have been shown to have a high specificity and sensitivity in celiac disease (CD) diagnosis, and their use is considered effective in improving the diagnostic accuracy of CD screening. <i>Aims:</i> To report the clinical details of transient IgA EmA positivity in a patient with Graves’ disease. <i>Methods:</i> We screened 48 patients (7 males, age range 19–79, median 58.3 years) for CD. They were hospitalized for thyroid disorders (30 patients had autoimmune hypothyroidism and 18 had Graves’ disease with clinical hyperthyroidism associated with diffuse goitre). CD screening was carried out on all patient…
Subcellular Localization of GLUT4 in Nonstimulated and Insulin-Stimulated Soleus Muscle of Rat
1992
Soleus muscles of fed rats were fixed by vascular perfusion with paraformaldehyde; individual fibers were teased and immunostained with a polyclonal antibody against the COOH-terminal of GLUT4. The binding sites were visualized by a horseradish peroxidase–coupled secondary antibody and diaminobenzidine. The fibers were embedded in epoxy resin and studied by electron microscopy. Strong immunoreactivity was found in subsarcolemmal clusters of vesicles and cisternae, Golgilike structures, and triadic junctions. Clusters of vesicles between myofibrils were occasionally stained. The plasma membrane was unlabeled. However, the plasma membrane was labeled when the rats had been injected with insul…
Cytoskeletal features in longitudinal and circular smooth muscles during development of the rat portal vein.
1995
Immunohistochemistry of alpha-smooth muscle actin and desmin, two markers of smooth muscle cell differentiation, and electron-microscopic observation of thick filaments of myosin were performed on the media of the developing rat hepatic portal vein to gain insights into the chronology of differentiation of its longitudinal and circular smooth muscles. In accordance with the ultrastructural distribution of thin filaments, staining of alpha-smooth muscle actin is lightly positive in the myoblasts at postnatal day 1 and then extends in probably all muscle cells of the developing vessel. Desmin, which appears later than alpha-smooth muscle actin in the two muscles, is distributed throughout the…