Disease relevance of Contracture

• Emery-Dreifuss muscular dystrophy (EDMD) is an X-linked recessive disorder characterized by slowly progressing contractures, wasting of skeletal muscle and cardiomyopathy [1].
• A video that contrasts kyphosis, gait, joint contractures, and mobility in mdx/utr(-/-) and alpha 7BX2-mdx/utr(-/-) mice can be accessed at http://www.jcb.org/cgi/content/full/152/6/1207 [2].
• Injury of control hearts during global ischemia, indexed by time-to-ischemic contracture, was accelerated by blocking adenosine receptors with 50 microM 8-(p-sulfophenyl) theophylline but was unaffected by addition of 20 nM N6-cyclopentyladenosine, an A1AR agonist [3].
• Mutations in TNNT3 cause multiple congenital contractures: a second locus for distal arthrogryposis type 2B [4].
• The fatty acids that are able to reduce the beating rate, particularly EPA and DHA, could effectively prevent and terminate lethal tachyarrhythmias (contracture/fibrillation) induced by high extracellular calcium concentrations or ouabain [5].

Psychiatry related information on Contracture

• She had early-onset hypotonia, generalized muscle wasting, with weakness especially of the neck muscles, joint contractures, mental retardation and high creatine kinase [6].

High impact information on Contracture

• Complications include capsular contracture and calcification and possibly connective tissue diseases such as scleroderma and rheumatoid arthritis, a subject of some controversy [7].
• Susceptibility to MH (MHS) is predicted by contracture tests on muscle tissue obtained by biopsy [8].
• Ventricular myocytes exhibit a nifedipine-sensitive inward calcium current (ICa) and contracture when they are voltage clamped from -40 to 0 millivolt in the presence of caffeine and in the absence of extracellular sodium [9].
• Potassium chloride versus voltage clamp contractures in ventricular muscle [10].
• High concentrations (80 to 90 millimolar) of the calcium buffers EGTA and citrate (less than 10(-7) molar free calcium ion) reversibly block excitation-contraction coupling in intact frog skeletal fibers, but do not block caffeine-induced contractures [11].

Chemical compound and disease context of Contracture

• Ouabain produced only contracture without positive inotropy [12].
• Further, penicillamine may have a more generalized application i the prevention of contractures in a variety of neuromuscular disorders [13].
• MH patients were identified by the halothane and halothane/caffeine contracture tests done in isolated muscle biopsy specimens [14].
• In control and RVF muscles, isoproterenol (1.0 x 10(-6)M) significantly increased twitch force and dP/dt and reduced K+ contracture, while ouabain increased twitch force, dP/dt, and K+ contracture [15].
• In the zero-flow protocol, draflazine also significantly reduced ischemic contracture and release of creatine kinase [16].

Biological context of Contracture

• Bax inactivation also improved postnatal growth rate and myofiber histology and decreased fixed contractures of Lama2(-/-) mice [17].
• Effects of inosine on glycolysis and contracture during myocardial ischemia [18].
• Added potassium chloride induced a contracture in which oxygen consumption, lactate production, and phosphorylase activity all increased [19].
• When oxidative phosphorylation was further reduced by hypoxia, glucose still prevented ischemic contracture; however, when oxidative phosphorylation dropped to near zero (near-anoxic) rates, glycolysis was inhibited, and glucose could only delay ischemic contracture to about 45 minutes [20].
• Homozygous mutant mice were characterized by growth retardation, skeletal dysplasia and joint contractures, thereby recapitulating essential aspects of the DTD phenotype in man [21].

Anatomical context of Contracture

• AD-ADMD is characterized by early contractures of elbows and Achilles tendons and a humero-peroneal distribution of weakness combined with a cardiomyopathy with conduction defects [22].
• In the absence of extracellular Na+ concentration [( Na+]o), carbachol no longer produced an increase in [Ca2+]i of cardiomyocytes and failed to enhance Na+-withdrawal contracture of the rat papillary muscle [23].
• Tolerance to subsequent acute severe hypoxia occurred in cells cultured in 1% O2 and was manifested as a delay in the time to full ATP-depletion rigor contracture during severe hypoxia and enhanced morphological recovery of myocytes at reoxygenation [24].
• X-linked arthrogryposis Type I (X-linked infantile spinal muscular atrophy) is a rare disorder showing hypotonia, areflexia, and multiple congenital contractures (arthrogryposis) associated with loss of anterior horn cells and death in infancy [25].
• Of four normal tissues assessed, two (hair follicles and tissues responsible for development of leg contractures) showed no change in radioresponse after treatment with indomethacin, one (hematopoietic tissue) exhibited radioprotection, and one (jejunum) exhibited slight radiosensitization (enhancement factor, 1.12) [26].

Gene context of Contracture

• UCMD, a severe disorder characterized by congenital muscle weakness, proximal joint contractures and marked distal joint hyperextensibility, has been considered a recessive condition, and homozygous or compound heterozygous mutations have been defined in COL6A2 and COL6A3 [27].
• OBJECTIVE: To measure the levels of prostaglandin endoperoxide H synthase (PGHS) isozymes (or cyclooxygenase, COX) in vivo during the development of joint contractures secondary to immobilization in rats [28].
• Different levels of COX-1 and COX-2 enzymes in synoviocytes and chondrocytes during joint contracture formation [28].
• Patients with a proliferative active disease (n = 14) had a significantly higher TIMP-1 concentration (525 +/- 136 ng/ml) than patients (n = 8) with a contracture in the late involutional and residual phase (286 +/- 41 ng/ml; p < 0.05) [29].
• We investigated the frequency of the 23 published MH linked RYR1 gene mutations in the Swiss MH population and compared our findings to the results of the in vitro contracture test (IVCT) [30].

Analytical, diagnostic and therapeutic context of Contracture

• In skeletal muscles isolated from newborn RyR3(-/- )mice, but not in those from adult mice, the twitch elicited by electrical stimulation and the contracture induced by caffeine were strongly depressed [31].
• CONCLUSIONS: The data indicate that ET-1 exacerbates ischemic contracture and worsens ventricular and coronary reperfusion dysfunction by activating ET(A) receptors via a mechanism likely involving activation of Na+/H- exchange in this model [32].
• Reperfusion with oxygenated perfusate shortly after peak contracture development resulted in a return of [Cai] to its preischemic level, resynthesis of creatine phosphate, no significant enzyme release, and no substantial loss of 5F-BAPTA from the heart [33].
• Ischemic contracture was initiated at about 10 minutes by buffer perfusion with nonglycolytic substrates whereas the addition of 11 mM glucose prevented contracture for 2 hours [20].
• Hypothermia enhanced caffeine contractures but also protected hearts from cell separations and CK release [34].

References