Search results for "Myofibril"
showing 10 items of 50 documents
A new familial congenital myopathy in children with desmin and dystrophin reacting plaques.
1995
In 5 children with a progressive congenital myopathy representing 3 different families, unusual histological, immunohistochemical and ultrastructural changes in skeletal muscle have been found. Histologically, this myopathy was characterized by the presence of fine hyaline plaques devoid of oxidative as well as ATPase enzyme activities. At the ultrastructural level plaques were composed of helical filaments and amorphous dense material. Helical filament storage corresponded to strong desmin as well as ubiquitin immunoreactivity. In addition they were also dystrophin positive. The exclusive appearance of desmin, ubiquitin and dystrophin positive plaques in muscle specimens from 5 children em…
Identification to cardiac conduction cells in humans and pigs according to their zonal distribution, using histological, immunohistochemical and morp…
2021
Abstract Histologically, the cardiac conduction network is formed of electrically isolated subendocardial fibers that comprise specialized cells with fewer myofibrils and mitochondria than cardiomyocytes. Our aim is to uncover regional variations of cardiac conduction fibers through histological and morphometric study in a porcine and human model. We analyzed five male adult human hearts and five male pig hearts. The left ventricles were dissected and sectioned in the axial plane into three parts: basal, middle third and apex regions. Cardiac conduction fibers study was carried out using hematoxylin-eosin and Masson's trichrome staining, and cardiac conduction cells and their junctions were…
Diethylene glycol (DEG)-associated myocardial changes: a pilot investigation of chronic intoxication in guinea-pigs.
1991
The myocardium of guinea pigs fed on sublethal doses of diethylene glycol (DEG) over a period of 2–11 days was examined for microscopical and ultrastructural changes. Coagulative myocytolysis and loss of myofibrils, not observed in the controls, was patchily distributed throughout the myocardium. The accompanying ultrastructural features included swelling, pleomorphism and hyperplasia of mitochondria with an associated distension of the interfibrillary spaces and a displacement, distortion and rupture of adjacent myofibrils.
Myofibrillar disorganization characterizes myopathy of camptocormia in Parkinson’s disease
2011
Camptocormia is a highly disabling syndrome that occurs in various diseases but is particularly associated with Parkinson’s disease (PD). Although first described nearly 200 years ago, the morphological changes associated with camptocormia are still under debate and the pathophysiology is unknown. We analyzed paraspinal muscle biopsies of 14 PD patients with camptocormia and compared the findings to sex-matched postmortem controls of comparable age to exclude biopsy site-specific changes. Camptocormia in PD showed a consistent lesion pattern composed of myopathic changes with type-1 fiber hypertrophy, loss of type-2 fibers, loss of oxidative enzyme activity, and acid phosphatase reactivity …
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…
Signal Characteristics of EMG with Special Reference to Reproducibility of Measurements
1975
Reliability and constancy of recordings of EMG signal characteristics were investigated from the measurements taken with miniature size surface electrodes during submaximal and maximal contraction of the rectus femoris muscle. The following EMG variables were studied: integrated EMG (IEMG) various bandwidths of the power spectral density function, mean power frequency (MPF), and rise time, amplitude and number of spikes of the averaged motor unit potential (AMUP). The results indicated that for most of the variables studied the reproducibility of measurements was better within the test session (reliability) than between the different test days (constancy). The reliability values for IEMG, M…
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…
Effects of age and prolonged running on proteolytic capacity in mouse cardiac and skeletal muscles.
1981
Male NMRI-mice, aged 3, 6, 9, and 12 months, were made to run for a period of 4 4 at a speed of 13.5 m/min on a motor-driven treadmill, 5 days after exertion, selected enzymatic estimates of acid and alkaline proteolytic as well as energy metabolic capacities were analyzed from the cardiac muscle and from the red and white parts of m. quadriceps femoris (MQF). The activities of alkaline and myofibrillar proteases increased most considerably in skeletal muscles with age. Cathepsin D and beta-glucuronidase activities were less affected in both muscles. Prolonged running increased the activities of cathepsin D, dipeptidyl aminopeptidase I and beta-glucuronidase in the white and, especially in …
Exhaustive physical exercise and acid hydrolase activity in mouse skeletal muscle
1978
Adult, untrained NMRI mice were exhausted on a motor-driven treadmill by an intermittent-type running programme. Serial cryostate sections for the staining of NADH-tetrazolium reductase, beta-glucuronidase, beta-N-acetylglucosaminidase, and beta-glycerophosphatase activities and for making hematoxylin-eosin staining were cut from m. quadriceps femoris 1, 2, 3, 5, 7, and 15 days after physical exhaustion. A strong increase in the activities of beta-glucuronidase and beta-N-acetylglucosaminidase was observed 7 days after exhaustion and the activity changes, which were similar for the both glycosidases, were more prominent in the highly oxidative red compared to less oxidative white fibres. Ac…
The disruption of myofibre structures in rat skeletal muscle after forced lengthening contractions.
1998
Specific antibodies against structural proteins (actin, desmin, dystrophin, fibronectin) of muscle fibres were used to study the effect of forced lengthening contractions on muscle microarchitecture. Tibialis anterior (TA) muscle of male Wistar rats were subjected to 240 forced lengthening contractions. At consecutive time points (0, and 6 h, 2, 4, and 7 days) after stimulation, the TA muscle was excised for biochemical and histological assays. Beta-Glucuronidase activity, a quantitative indicator of muscle damage, showed increased values 2-7 days after the lengthening, peaking on day 4 (11.7-fold increase). A typical course of histopathological changes (myofibre swelling, necrosis and rege…