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[When the leg is the victim of the foot].

Man (homo-erectus, plantigrade) is in constant contact with the ground via his feet which are platforms on which the legs and, above all, the entire body rest. When the body moves, the only segment which remains stable and fixed is the foot, which forms the point of departure of all the muscular actions of this moving body. The slightest deformity of this platform, this foot, will lead to skeletal, musculotendinous and neurovascular problems in the legs, and to pain. Pain due to skeletal problems may be related to fatigue fractures (tibia, fibula) and to posterior tibial periostitis. Pain may also be due to musculotendinous problems which are characterised by a muscle bed syndrome (anterolateral, posterior) or tensosynovitis. Neurovascular problems are typified by a tarsal sinus syndrome, a musculocutaneous nerve syndrome and dysfunction of Lejears' sole during filling in flat feet and during emptying in hollow feet.

Foot Diseases↗

PubMed2005

[Apical left ventricular aneurysm without atrio-ventricular block due to a lamin A/C gene mutation].

UNLABELLED: Mutations in LMNA gene encoding two ubiquitously expressed nuclear proteins, lamins A and C, give rise to up to 7 different pathologies affecting specific tissues. Three of these disorders affect cardiac and/or skeletal muscles with atrio-ventricular conduction disturbances, dilated cardiomyopathy and sudden cardiac death as common features. RESULTS: A new LMNA mutation (1621C>T, R541C) was found in two members of a French family with a history of ventricular rhythm disturbances and an uncommon form of systolic left ventricle dysfunction. The two patients: the proband and his daughter, were affected and exhibited an atypical form of dilated cardiomyopathy with an unexplained left ventricle aneurysm revealed by ventricular rhythm disturbances without atrio-ventricular block. CONCLUSION: This finding reinforces the highly variable phenotypic expression of LMNA mutation and emphasizes the fact that LMNA mutations can be associated with different cardiac phenotypes.

Adult↗

PubMed1994

[Disorders of walking in elderly subjects: towards new concepts].

While gait disorders directly related to a muscular, skeletal neurological defect are easily recognized, others, which we address here, appear to result from some unknown and mysterious mechanism. Gait disorders in elderly patients cannot be conceived as a simple impairment in muscle, tendon or joint effectors but must be assessed in relation to defective central programmation or dysfunctioning synergy. Posture is the result of a series of successive reflex reactions, and locomotion itself is the result of a series of sequential stimulations and inhibitions originating in the spinal generator controlled by supraspinal centres. Obviously, in man, cortical and subcortical activation is essential as is the activity of the limbic system and the associative zones, together with the basal gangia and the cerebellum. Peripheral proprioception accelerates consciousness of information originating in the muscles, tendons and joints; vestibular and visual input adds further, though redundant, information. Advanced methods of quantifying posture and walking offer a new approach to the analysis of gait disorders. The Bessou locometer analyzes physiological senescence leading to an inconscient strategy which decreases the speed and length of each step. This mechanism might be explained by the aging process leading to non-necrotic cell failure without any specific lesion, vascular for example. Another method is the ELITE system (Elaboratore de Immagini Televisive). This system evaluates the way the subject modelizes and reconstructs his environment. Interesting results have been obtained with postural imbalance induced by visual stimulations.

Aged↗

PubMed2003

Overexpressions of myoglobin and antioxidant enzymes in ragged-red fibers of skeletal muscle from patients with mitochondrial encephalomyopathy.

To determine the relationship between myoglobin (Mb) and the defense system against reactive oxygen species in various myopathies, we performed immunohistochemical analyses of Mb and various antioxidant enzymes, including manganese superoxide dismutase (Mn-SOD), copper zinc SOD (CuZn-SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). Biopsied muscle specimens were obtained from patients with chronic progressive external ophthalmoplegia (CPEO), Kearns-Sayre syndrome (KSS), Duchenne muscular dystrophy (DMD), and polymyositis (PM). In patients with CPEO/KSS, stainings of Mb, SOD, CAT, and GSH-Px in nonatrophic ragged-red fibers (RRFs) were more intense than those in non-RRFs. These pronounced stainings corresponded to ragged-red lesions. The staining intensities of these antioxidant enzymes were significantly correlated with that of Mb (P < 0.001). Atrophic RRFs in specimens from patients with CPEO/KSS showed intense stainings of these antioxidant enzymes but not intense staining of Mb. In specimens from patients with DMD/PM, the antioxidant enzymes but not Mb were overexpressed in degenerative fibers. These results suggest that oxidative stress is associated with Mb expression specifically in mitochondrial diseases. The antioxidant enzymes seem to be upregulated to protect against muscle damage in nonatrophic RRFs. However, the Mb-mediated oxidative damage may become more extensive and result in further mitochondrial dysfunction and progressive atrophy of RRF with impaired upregulation of Mb.

Adult↗

PubMed1997

Relative susceptibility of endothelium and myocardial cells to ischaemia-reperfusion injury.

We have investigated the timescale, extent and sequence of endothelial, myocardial and smooth muscle cell dysfunction following ischaemia-reperfusion in the isolated rat heart. Myocardial function in the form of aortic flow was evaluated in the working heart preparation. Vasodilatation induced by endothelium-dependent agent 5-hydroxytryptamine (5-HT) and endothelium-independent substance glyceryl trinitrate (GTN) was used to assess endothelial and smooth muscle function, respectively. The percentage recovery of 5-HT response and aortic flow (endothelial vs. myocardial function) plus 5-HT response and GTN effect (endothelial function vs. smooth muscle response) after a period of ischaemia was statistically analysed by Wilcoxon's signed rank test. A possible correlation between structural and functional changes in coronary vascular endothelium after ischaemia was also explored by comparing endothelial dysfunction with morphological assessment of endothelial damage seen after ischaemia. The experiments were performed at two clinically relevant temperatures of 20 degrees C and 4 degrees C. There was no significant difference in the percentage recovery of aortic flow and 5-HT response or in 5-HT response and GTN effect after 30 min of unprotected ischaemia at 4 degrees C. The same duration of ischaemia at 20 degrees C led to significantly better recovery of GTN effect as compared with 5-HT response, but there was no difference in the recovery of aortic flow and 5-HT response. Sixty minutes of unprotected ischaemia at both temperatures caused significantly better recovery of aortic flow and GTN effect as compared with 5-HT response; 60 min of ischaemia protected by an infusion of a cardioplegic solution (protected ischaemia) at 4 degrees C had no significant effect on the recovery of the three parameters. Periods of 90, 120, 180 and 240 min of protected ischaemia at 4 degrees C, and 60, 90 and 120 min of protected ischaemia at 20 degrees C resulted in significantly better recovery of aortic flow compared with 5-HT response and of GTN effect as compared to 5-HT response. This demonstrates varying susceptibility of different cell types to ischaemic injury and highlights the strong vulnerability of endothelium to ischaemic damage as compared with myocytes and smooth muscle cells. Furthermore, there was lack of correlation between post-ischaemic endothelial dysfunction and microscopically assessed structural damage.

Animals↗

PubMed2004

Effects of creatine supplementation on renal function.

Creatine is a popular supplement used by athletes in an effort to increase muscle performance. The purpose of this review was to assess the literature evaluating the effects of creatine supplementation on renal function. A PubMed search was conducted to identify relevant articles using the keywords, creatine, supplementation, supplements, renal dysfunction, ergogenic aid and renal function. Twelve pertinent articles and case reports were identified. According to the existing literature, creatine supplementation appears safe when used by healthy adults at the recommended loading (20 gm/day for five days) and maintenance doses (</=3 gm/day). In people with a history of renal disease or those taking nephrotoxic medications, creatine may be associated with an increased risk of renal dysfunction. One case report of acute renal failure was reported in a 20-year-old man taking 20 gm/day of creatine for a period of four weeks. There are few trials investigating the long-term use of creatine supplementation in doses exceeding 10 gm/day. Furthermore, the safety of creatine in children and adolescents has not been established. Since creatine supplementation may increase creatinine levels, it may act as a false indicator of renal dysfunction. Future studies should include renal function markers other than serum creatinine and creatinine clearance.

Acute Kidney Injury↗

PubMed2005

Neurobiology of fibromyalgia syndrome.

Accumulating evidence suggests that fibromyalgia syndrome (FM) pain is maintained by tonic impulse input from deep tissues, such as muscle and joints, in combination with central sensitization mechanisms. This nociceptive input may originate in peripheral tissues (trauma and infection) resulting in hyperalgesia/allodynia and/or central sensitization. Evidence for abnormal sensitization mechanisms in FM includes enhanced temporal summation of delayed pain in response to repeated heat taps and repeated muscle taps, as well as prolonged and enhanced painful after-sensations in FM patients but not control subjects. Moreover, magnitudes of enhanced after-sensations are predictive of FM patients' ongoing clinical pain. Such alterations of relevant pain mechanisms may lead to longterm neuroplastic changes that exceed the antinociceptive capabilities of affected individuals, resulting in ever-increasing pain sensitivity and dysfunction. Future research needs to address the important role of abnormal nociception and/or antinociception for chronic pain in FM.

Acute Disease↗

PubMed1999

Pontocerebellar hypoplasia associated with respiratory-chain defects.

Pontocerebellar hypoplasias are congenital disorders of brain morphogenesis which include such diverse etiologies as carbohydrate-deficient glycoprotein syndrome type 1, cerebromuscular dystrophies (Walker-Warburg syndrome, Fukuyama syndrome, muscle-eye-brain disease) and at least two types of autosomal recessive neurodegenerations known as pontocerebellar hypoplasia type I and II. Pontocerebellar hypoplasia type 1 is a lethal phenotype and clinical features include congenital contractures, respiratory insufficiency, central and peripheral motor dysfunction and spinal anterior horn degeneration. Type 2 is characterized by progressive microcephaly, extrapyramidal dyskinesia and normal spinal cord findings. In this paper, we describe a girl, born at 33 weeks of gestation, presenting with respiratory insufficiency and multiple contractures. MRI scan of the brain demonstrated pontocerebellar hypoplasia and cortical and diffuse periventricular white matter abnormalities. Postmortem examination showed pontocerebellar hypoplasia with extensive gliosis of the periventricular white matter and of the basal ganglia with normal spinal cord findings. Histology of skeletal muscle was normal. Biochemical analysis demonstrated multiple deficiencies of respiratory chain enzymes in skin fibroblasts. This case demonstrates a lethal phenotype of pontocerebellar hypoplasia without spinal cord abnormalities associated with a respiratory-chain disorder. The diagnostic workup in a patient whose brain image shows pontocerebellar hypoplasia should include a search for respiratory-chain impairment.

Abnormalities, Multiple↗

PubMed2006

A mutation in the fast skeletal muscle troponin I gene causes myopathy and distal arthrogryposis.

OBJECTIVE: To describe a three-generation family with distal arthrogryposis associated with myopathy and caused by a mutation in the gene encoding for sarcomeric thin filament protein troponin I, TNNI2. METHODS: The authors performed clinical investigations and reviewed medical records. Muscle biopsy specimens were obtained for morphologic analysis. Genomic DNA was extracted from blood and analyzed for mutations in TNNI2. RESULTS: The five affected individuals had predominantly distal congenital joint contractures, mild facial involvement (mild micrognathia, narrow palpebral fissures), and no detectable muscle weakness. The four affected adults had slightly increased levels of creatine kinase in blood, and muscle biopsy specimens showed findings of myopathy with changes restricted to type 2 fibers. These included variability of muscle fiber size, internalized nuclei, and increased interstitial connective tissue. Analysis of TNNI2 encoding the troponin I isoform expressed in type 2 muscle fibers disclosed a heterozygous three-base in-frame deletion, 2,918-2,920del, skipping the highly conserved lysine at position 176. The mutation was present in all 5 affected individuals but was not identified in any of the 11 unaffected family members. CONCLUSION: Distal arthrogryposis type 1 is genetically heterogeneous, and myopathy due to sarcomeric protein dysfunction may be one underlying cause of the disease.

Adult↗

PubMed1979

Lactate elimination in man: effects of lactate concentration and hepatic dysfunction.

Lactate elimination was studied in twenty-six healthy volunteers during primed constant lactate infusion or multiple lactate injection tests, at blood lactate concentrations of 1-8 mmol-1. Although lactate elimination fitted a single exponential curve over a 30 min period, a significant correlation between the rate removal constant (KL) and the peak blood lactate concentration (Lphi) was demonstrated: loge KL = -2.43-0.132 Lphi (P = 0.003, r = 0.63, n = 20) This suggests that lactate removal does not follow first order kinetics over a wide concentration range but becomes saturated at relatively low blood lactate concentrations. Estimates of the lactate distribution volume did not differ significantly at different dosage levels, but remained in the range 270-300 ml kg-1. Skeletal muscle uptake accounted for about 26% of the infused lactate load. Seven patients with well-compensated hepatic cirrhosis were compared with a group of six control subjects during primed constant infusion tests. Fasting and steady state blood lactate concentrations achieved were similar in both groups. A significant prolongation in lactate half-life was demonstrated in the cirrhotics (18.8 +/- 1.4 min (mean +/- SEM) compared to 14.7 +/- 2.2 min; P less than 0.02). Since peripheral uptake of lactate in the forearm was similar in the two groups, this suggests that hepatic lactate uptake was impaired, due either to hepatocyte dysfunction or portal diversion.

Adult↗

PubMed1993

Skeletal troponin C reduces contractile sensitivity to acidosis in cardiac myocytes from transgenic mice.

Depressed contractile function plays a primary role in the pathophysiology of acute myocardial ischemia. Intracellular acidification is an important factor underlying the inhibition of force production in the ischemic myocardium. The effect of acidosis to depress contractility is markedly greater in cardiac as compared to skeletal muscle; however, the molecular basis of this difference in sensitivity to acidosis is not clearly understood. In this report, we describe transgenic mice that express the fast skeletal isoform of troponin C (sTnC) in cardiac muscle. In permeabilized single cardiac myocytes the shift in the midpoint of the tension-pCa relationship (i.e., pCa50, where pCa is -log[Ca2+]) due to lowering pH from 7.00 to 6.20 was 1.27 +/- 0.03 (n = 7) pCa units in control cardiac TnC (cTnC) expressing myocytes and 0.96 +/- 0.04 (n = 11) pCa unit in transgenic cardiac myocytes (P < 0.001). The effect of pH to alter maximum Ca(2+)-activated tension was unchanged by TnC isoforms in these cardiac myocytes. In a reciprocal experiment, contractile sensitivity to acidosis was increased in fast skeletal muscle fibers following extraction of endogenous sTnC and reconstitution with purified cTnC in vitro. Our findings demonstrate that TnC plays an important role in determining the profound sensitivity of cardiac muscle to acidosis and identify cTnC as a target for therapeutic interventions designed to modify ischemia-induced myocardial contractile dysfunction.

Acidosis↗

PubMed1998

Multiple myeloma with associated polyneuropathy in a German shepherd dog.

A 12-year-old female, neutered German shepherd dog developed progressive hindlimb followed by forelimb ataxia leading to tetraplegia. Neurological examination suggested lower motor dysfunction. Biochemical evaluation revealed a monoclonal hypergammaglobulinaemia, hypoalbuminaemia and hypercalcaemia. Multiple lytic lesions were identified radiographically in numerous bones. A bone marrow aspirate confirmed the diagnosis of multiple myeloma, with large numbers of plasma cells seen in clusters. An electromyogram revealed positive sharp waves and fibrillation potentials in the skeletal muscles of the limbs, suggesting a polyneuropathy. The dog was treated with chemotherapy using melphalan and prednisolone. Both the hypergammaglobulinaemia and the polyneuropathy resolved and the dog had normal motor function four weeks after commencing treatment. Polyneuropathy may occur as a paraneoplastic syndrome secondary to myeloma, and in this case was reversible following treatment of the underlying disease.

Animals↗

PubMed2004

Phosphodiesterase 5 enzyme and its inhibitors: update on pharmacological and therapeutical aspects.

Cyclic nucleotides are important secondary messengers that control many physiologic processes, including smooth muscle contractility. Phosphodiesterases (PDEs) comprise of a superfamily of metallophosphydrolases that specifically cleave the 3',5'-cyclic phosphate moiety of cAMP and/or cGMP to produce the corresponding 5' nucleotide. Currently 21 PDE genes have been cloned and are classified into 11 families (1-11) according to their sequence of homology, biochemical and pharmacological properties. Phosphodiesterase type 5 (PDE5) is one of the members of the superfamily that specifically cleaves cyclic guanosine monophosphate (cGMP), a key intracellular secondary messenger. It is composed of 875 amino acids and was first identified in lungs, vascular and tracheal smooth muscle, and platelets. PDE5 is selectively inhibited by sildenafil, vardenafil and tadalafil, and less selectively by zaprinast and dipyridamole. PDE5 inhibitors have been reported to possess antiplatelet aggregation, weak cardiac inotropic effects and vascular relaxant properties. The tissue distribution of the PDE5 family is relatively restricted compared with other PDEs. Still, recent immunohistochemical and reverse transcriptase-polymerase chain reaction analysis have demonstrated the presence of anti-PDE5 antibodies and PDE5 transcripts in rat cerebellum, kidney, pancreas, aortic smooth muscle cells, heart, placenta, skeletal muscle, and, to a much lesser extent, in other regions of the brain, liver and lungs. Research in this field is intense, with a goal of identifying and developing new, selective PDE5 inhibitors that would be beneficial in a number of maladies, as well as angina, hypertension and erectile dysfunction (ED).

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed1995

[Immunochemical and immunohistochemical study of calpastatin, an endogenous calpain inhibitor, in the masseter muscle of the rabbit].

The calpains-calpastatin system (calcium-activated neutral proteases and endogenous inhibitor) seems to be, in the skeletal muscle, a fine enzymatic system of myofibrillar turnover regulation, in normal as well as pathological conditions (for ex., dystrophic muscle). The purpose of the research is to establish in qualitative and quantitative terms whether the level of calpastatin can evidence differences between a muscle in normal activity conditions and one having dysfunctional alterations experimentally induced. So the masseter muscle of rabbit in normal conditions and with experimentally modified occlusal plane has been used. Our results confirm the presence of the 68 KDa calpastatin in the masseter muscle. The presence of the inhibitor in the same subcellular structures in which the calpains have been detected (myofibrillars, sarcolemma, endomysial connective) has been confirmed. Finally, variations in calpastatin amount in the muscle of animals experimentally treated with respect to the controls have been found. Thus, calpastatin seems to act as a marker of muscle dysfunctions connected to occlusal plane alteration and to loss of vertical dimention.

Animals↗

PubMed1993

Cardiac and skeletal muscle disease in systemic sclerosis (scleroderma): a high risk association.

To examine the possible relationship between cardiac and skeletal muscle disease in systemic sclerosis, we reviewed computerized records of 1095 consecutive patients with systemic sclerosis. One hundred eighty three (17%) had skeletal myopathy. Thirty-nine (21%) of the 183 fulfilled criteria for myocardial disease, compared with 90 (10%) of the 912 without myopathy (p < 0.0001.) Nineteen (10%) of the 183 had clinical CHF compared with 38 (4%) of the remainder (p < 0.002.) Fifteen (8%) of the patients with myopathy died of cardiac causes compared with 27 (3%) of the 912 without myopathy (p < 0.002.) Twenty-five patients with coexistent myopathy and myocardial disease, in the absence of other identifiable contributing causes, were identified. This group was characterized by a high incidence of cardiac conduction abnormalities (60%) and by the severity of the myocardial dysfunction and arrhythmias, both atrial and ventricular that they experienced. Eighteen of these 25 patients died; 12 (67%) died suddenly. Eight of the 18 (44%) had intractable CHF, which directly contributed to their deaths. Myocardial fibrosis was the predominant histologic abnormality at autopsy. However, autopsy of a patient who died in the context of acute "myocarditis" showed severe myocytolysis with contraction band necrosis but without inflammation or fibrosis; this is consistent with possible ischemically mediated injury. We conclude that skeletal and cardiac muscle disease in systemic sclerosis are associated. Patients with myopathy are at increased risk for CHF, sustained symptomatic arrhythmias, and cardiac death, particularly sudden death.

Adolescent↗

PubMed2005

Metabolic syndrome increases endogenous carbon monoxide production to promote hypertension and endothelial dysfunction in obese Zucker rats.

Vascular heme oxygenase (HO) metabolizes heme to form carbon monoxide (CO). Increased heme-derived CO inhibits nitric oxide synthase and can contribute to hypertension via endothelial dysfunction in Dahl salt-sensitive rats. Obese Zucker rats (ZR) are models of metabolic syndrome. This study tests the hypothesis that endogenous CO formation is increased and contributes to hypertension and endothelial dysfunction in obese ZR. Awake obese ZR showed increased respiratory CO excretion, which was lowered by HO inhibitor administration [zinc deuteroporphyrin 2,4-bis glycol (ZnDPBG) 25 micromol.kg(-1).24 h(-1) ip]. In awake obese ZR, chronically instrumented with femoral arterial catheters, blood pressure was elevated but was decreased by the HO inhibitor ZnDPBG. Body weight, blood glucose, glycated hemoglobin, plasma insulin, total and LDL cholesterol, oxidized LDL, and triglyceride levels were elevated in obese ZR, and, except for LDL cholesterol, were unchanged by HO inhibition. Total HO-1 protein levels were not different between lean and obese ZR aortas. In vitro experiments used isolated skeletal muscle arterioles with constant pressure and no flow, or constant midpoint, but altered endpoint pressures to establish graded levels of luminal flow. In obese ZR arterioles, responses to ACh and flow were attenuated. Acute in vitro pretreatment with an HO inhibitor, chromium mesoporphyrin, enhanced ACh and flow-induced dilation and abolished the differences between groups. Furthermore, exogenous CO prevented the restoration of flow-induced dilation by the HO inhibitor in obese ZR arterioles. These results suggest that HO-derived CO production is increased and promotes hypertension and arteriolar endothelial dysfunction in obese ZR with metabolic syndrome independent of affecting metabolic parameters.

Animals↗

PubMed1995

Twitch response of striated muscle in patients with progressive external ophthalmoplegia, mitochondrial myopathy and focal cytochrome c-oxidase deficiency.

Some aspects of the contractile properties of skeletal muscle in patients with progressive external ophthalmoplegia (PEO), mitochondrial myopathy and focal cytochrome c-oxidase deficiency were investigated by studying the twitch response (TR) of the tibialis anterior muscle both at rest and after maximum isometric contraction. The results of needle electromyography were normal in four of the six examined patients, and myopathic in the remaining two. A slowing in muscle relaxation was the most frequently observed abnormality; significantly prolonged muscle contraction times and reduced twitch torque potentiation values after isometric contraction were also detected. TR abnormalities in PEO patients may be due either to a dysfunction of the contractile machinery depending upon impaired muscle energy supply or to altered muscle fiber characterized by the predominance of type I slow fiber. In addition to conventional electromyographic investigations, TR study may be a useful diagnostic tool in PEO patients.

Adult↗

PubMed1998

Local relation between oxidative metabolism and perfusion in leg muscles of patients with heart failure studied by magnetic resonance imaging and spectroscopy.

BACKGROUND: We studied the local relation of muscle perfusion and metabolism in patients with severe chronic heart failure. Alterations of skeletal muscle blood flow and oxidative capacity contribute to exercise intolerance in these patients. The interdependence of both parameters has often been questioned. METHODS AND RESULTS: With the use of nuclear magnetic resonance, we quantified leg and muscle perfusion during reactive hyperemia in 7 patients with heart failure (New York Heart Association class III and IV) and 7 age-matched control subjects from the difference in longitudinal relaxation rate (1/T1). By using 31P nuclear magnetic resonance spectroscopy, we assessed oxidative metabolism from the creatine rephosphorylation time constant after a short ischemic exercise. Phosphocreatine recovery is slowed (74.6 +/- 11.3 vs 49.9 +/- 13.9 seconds, p = .002) and reactive hyperemic flow is reduced (48.5 +/- 24.9 vs 113 +/- 30.4 mL/100 mL per minute, p = .0005). CONCLUSIONS: By using a totally noninvasive protocol, we demonstrated that reactive hyperemic flow correlates with oxidative capacity in calf muscles from patients with heart failure, showing that exercise performance and local circulatory dysfunction are decreased in parallel in severe heart failure.

Aged↗