Search results for "denervation"
showing 10 items of 60 documents
Low Levels of Acetylcholine Receptor Delta-Subunit Message and Protein in Human Thymus Suggests the Occurrence of ‘Triplet Receptors’ in Thymic Myoid…
2000
Myasthenia gravis (MG) is an autoimmune disease caused by autoantibodies against the acetylcholine receptor (AChR) at the neuromuscular junction [1]. The muscular AChR has been extensively characterized [2], but whether the muscular AChR plays a role during the initiation of MG is unknown [3]. The muscular AChR is a pentameric ion channel composed of 4 different subunits [2, 4]. The fetal AChR expressed during intrauterine life and after denervation of adult muscle exhibits an α2βδγ composition, while the adult AChR expressed after birth in innervated muscle exhibits an α2βδγ composition [4]. The α-subunit contains the main epitopes recognized by MG autoantibodies [2]. The human muscle AChR…
Role of nitric oxide and nitric oxide synthases in experimental models of denervation and reinnervation.
2001
Nitric oxide (NO) is a short-living free molecule synthesized by three different isoforms of nitric oxide synthases (NOS)—neuronal NOS, endothelial NOS, and inducible NOS—associated with neuromuscular transmission, muscle contractility, mitochondrial respiration, and carbohydrate metabolism in skeletal muscle. Neuronal NOS is constitutively expressed at the muscle fiber sarcolemma linked to the dystrophin-glycoprotein complex and concentrated at the neuromuscular endplate. There is increasing evidence that altered expression of neuronal NOS plays a role in muscle fiber damage in neuromuscular diseases such as dystrophinopathies and denervating disorders. Although there have been some previo…
Sonographische Verlaufskontrolle nach experimenteller Muskeldenervierung
2008
AIM: To describe sonographical results following acute, experimental muscle denervation. METHOD: Denervation of the supraspinatus and infraspinatus muscles was performed in 28 New Zealand white rabbits by segmental resection of the suprascapular nerve. The changes in the sonographic image of the muscles were follow up and documented at short intervals over 2 months. RESULTS: The sonographically detectable changes following denervation follow a definite pattern. In addition to the reduction in muscle diameter, sonographical signs of denervation include an increase of echodensity and an inhomogeneity of echotexture that appeared on day 14 after injury and became more prominent at larger inter…
DNA-fragmentation and expression of apoptosis-related proteins in experimentally denervated and reinnervated rat facial muscle
1997
Muscle fibres may undergo apoptotic cell death in several neuromuscular disorders such as denervated muscle fibres in spinal muscular atrophies. We investigated DNA-fragmentation (in situ by the TUNEL-method) and expression of apoptosis-associated proteins in experimentally denervated and reinnervated rat facial muscle up to 24 weeks after surgery to evaluate the rate and time lapse of apoptotic muscle fibre loss. While denervated muscle displayed constantly high rates of DNA-fragmentation, denervated and immediately reinnervated muscle showed a distinct decrease of primarily elevated DNA-cleavage, finally resembling rates of normal controls. Denervated muscle fibres revealed strong immunor…
Morphology of Skeletal Muscle
2013
Skeletal muscle makes up the largest organ of the body, by both volume and weight, comprising more than 40 %. More than 500 diseases concern muscle tissue, the majority of which originate in muscle, others secondarily affect the muscle, foremost by denervation. The functional and structural dependence of skeletal muscle on innervation—that is, the peripheral and central nervous systems—renders muscle tissue unique and adds a dimension to the nosology, more obviously than in other organs. Therefore, diseases affecting muscle are also termed neuromuscular diseases. Within the nosological spectrum of the muscle parenchyma, which encompasses hereditary and acquired conditions, muscular dystroph…
Chapter 33 Experimental human models of neuropathic pain
2006
Publisher Summary This chapter reviews human surrogate models of neuropathic pain that focus on the mechanisms of symptom generation. A vast array of human surrogate models exists for ongoing symptoms, for positive sensory symptoms, and for sensory loss. The chapter discusses that by design, human surrogate models of neuropathic pain involve a reversible modulation of the properties of the nociceptive system such as its acute plasticity (phase 2). They usually do not create a long-lasting and potentially irreversible modification (phase 3). The denervation and ectopic activity of phase 3 can be modeled to a certain extent by transient nerve compression–ischemia and by topical capsaicin. By …
Clinical neurophysiology and imaging of nerve injuries: preoperative diagnostic work-up and postoperative monitoring
2015
Peripheral nerve injuries are a heterogeneous group of lesions that may occurs secondary to various causes. Several different classifications have been used to describe the pathophysiological mechanisms leading to the clinical deficit, from simple and reversible compression-induced demyelination, to complete transection of nerve axons. Neurophysiological data localize, quantify, and qualify (demyelination vs . axonal loss) the clinical and subclinical deficits. High-resolution ultrasound can demonstrate the morphological extent of nerve damage, fascicular echotexture (epineurium vs . perineurium, focal alteration of the cross-section of the nerve, any neuromas, etc. ), and the surrounding t…
Effect of Electrical Stimulation on Denervated Muscle
1986
The possibilities of noninvasive treatment in peripheral nerve injuries are limited. Although it is well known that the severance of a nerve results in paralysis of the dependent tissue, the methods of treating a denervated muscle are still controversial. The most obvious result of denervation is muscle atrophy and paralysis. In 1841 Reid forced the denervated muscle to contract by electrical stimulation to replace the loss of activity and observed that this treatment retarded atrophy. Since then, there has been continuing interest in preventing muscle atrophy with electrotherapy. Peripheral nerve injuries in the two world wars were, for instance, extensively treated with electrical stimula…
STUDIES ON NORMAL AND DENERVATED SKELETAL MUSCLE CHROMATIN
1980
Publisher Summary This chapter presents studies on normal and denervated skeletal muscle chromatin. It has been reported that the inhibitors of RNA and protein synthesis can prevent the appearance of some biochemical modifications of muscle, generally induced by denervation. This observation suggests that the gene expression of muscle fiber is under motoneuron control. On the other hand, it is well known that in eukaryotic cells exists a close relationship between chromatin properties and the gene expression. In a study, some properties of normal and 7-days denervated muscle chromatin were investigated to establish whether the changes in protein metabolism in denervated skeletal muscle are …