Immunohistochemical localization of chymase; a mast cell marker and clinical significance in diseased human skeletal muscle

In the advanced stage of dystrophinopathy, cardiac dysfunction is a serious complication for prognosis. Recently, an angiotensin converting enzyme (ACE), which converts angiotensin (A) 1 to A 2, has been reported to be effective for cardiac insufficiency. The A 2 is produced more dominantly in the path via the production of a neutral serine protease, chymase (MW 25,000), secreted from the mast cell. We have observed localization of chymase in diseased human skeletal muscle tissues, and evaluated its clinical significance. The frozen muscle biopsied specimens from 91 neuromuscular disorders (muscular dystrophies, inflammatory myopathies and neurogenic muscular disorders) were stained by using monoclonal antibody against the chymase, and the positive cells in a whole sectional field were counted. In the serial sections, we also performed routine histochemistry and immunostainings of immunological markers (CD4, CD8 and others) as well as the apoptotic proteins for comparison. RESULTS: The chymase-positive mast cells were scattered mainly in the endomysium, partly in the perimysium and around small vessels. Although the positivity was not disease specific, more numerous strongly positive cells were observed in dystrophinopathy and inflammatory myopathies, but less in myotonic dystrophy and neurogenic muscle disorders. In the normal control muscle, however, strongly positive cells appeared less frequently than in the above mentioned diseased muscles. The chymase-positive cells partly corresponded to the ubiquitin-positive ones, but perforin, granzyme A, Fas and Bcl-2 did not. In conclusion, the chymase-positive mast cell may play a primary or secondary role in the diseased muscle, and their more abundant appearance in dystrophinopathy and some other myopathies suggest the effectiveness of an ACE blocker, an anti-chymase drug.     

Skeletal muscle mitochondrial myopathy as a cause of exercise intolerance in a horse

Although exertional myopathies are commonly recognized in horses, specific etiologies have not been identified. This is the first report in the horse of a deficiency of Complex I respiratory chain enzyme associated with profound exercise intolerance. Physical examination, routine blood tests, endoscopy, and ultrasonograms of the heart and iliac arteries were unremarkable. With slow, incremental exercise (speeds 1.5-7 m/s), the Arabian mare showed a marked lactic acidosis, increased mixed venous PVO2, and little change in oxygen consumption. Muscle biopsies contained large accumulations of mitochondria with bizarre cristae formations. Biochemical analyses revealed a very low activity of the first enzyme complex in the mitochondrial respiratory chain (NADH CoQ reductase). The exercise intolerance and muscle stiffness in this horse were attributed to a profound lactic acidosis resulting from impaired oxidative energy metabolism during exercise.     

Alteration in diaphragmatic function during cardiac insufficiency: potential pharmacology modulation

Respiratory muscle dysfunction has been demonstrated in several clinical situations including chronic respiratory disease, such as chronic obstructive pulmonary disease, as well as cardiac insufficiency. In the latter case, respiratory muscle dysfunction has been demonstrated in acute situation (cardiogenic shock) and in chronic cardiac insufficiency. In the former case, it has been shown in an animal model that respiratory muscle dysfunction could influence markedly the outcome of cardiogenic shock. In chronic cardiac insufficiency histologic, biochemical and contractile abnormalities of the respiratory muscles have been demonstrated in an animal model as well as in humans. These alterations may account, at least in part, for the sensation of dyspnea that these patients encountered. Finally, several pharmacological agents such as angiotensin-converting enzyme inhibitors have been shown to restore muscle abnormalities observed during chronic cardiac insufficiency.     

Coenzyme-A-dependent esterification of cholesterol in rat intestinal mucosa

Rat intestinal mucosa contains an enzyme which catalyses the esterification of cholesterol. The enzyme is CoA-dependent and probably an acyl-CoA: cholesterol acyltransferase (ACAT) (E.C.2.3.1.26). Maximal activity in vitro is obtained when long chain acylcarnitines, CoA and carnitine palmityltransferase are used as an acyl-CoA generating system. The enzyme is localized in the microsomal fraction, has a pH optimum between 6.4-7.2, and oleate is the preferred acyl group. The activity of the enzyme is highest in the proximal jejunum, and has a capacity that can account for all cholesteryl esters found in intestinal rat lymph.     

Carnitine affects octanoate oxidation to carbon dioxide and dicarboxylic acids in colostrum-deprived piglets: in vivo analysis of mechanisms involved based on CoA- and carnitine-ester profiles

Newborn, colostrum-deprived piglets (n = 21) were used to study the effects of L-carnitine supplementation on the in vivo oxidation of [1-14C]octanoate to CO2 and dicarboxylic acids. Pigs were fitted with arterial and bladder catheters and were infused with octanoate (supplying 35-100% of piglets' energy expenditure) and with or without valproate for a period of 24 h. After achieving steady-state octanoate oxidation, carnitine was coinfused [50 mumol/kg 0.75 prime plus 20 mumol/h.kg 0.75)], and deviations in the octanoate oxidation rate, dicarboxylic acid excretion rate, and carnitine metabolism were monitored. At the end of the 24-h infusion, samples of liver and muscle were analyzed for carnitine- and CoA-esters by HPLC. Carnitine stimulated octanoate oxidation by 7% (P < 0.05) and decreased dicarboxylic acid excretion by 45% (P < 0.05). Carnitine supplementation increased (P < 0.05) concentrations of carnitine and acetyl carnitine in hepatic tissue (three- and 55-fold, respectively) and plasma (seven- and 11-fold); whereas, muscle-carnitine concentration doubled upon carnitine supplementation, but acetyl carnitine concentration remained unaltered. Urinary excretion of acetyl and free carnitine also increased with carnitine supplementation, but accounted for < 10% of carnitine infused. Hepatic total CoA and CoA esters increased with carnitine supplementation, whereas muscle acetyl-CoA decreased. Valproate had only marginal effects on octanoate metabolism. These data confirm the hypothesis that carnitine effects the in vivo oxidation of octanoate in colostrum-deprived piglets and suggest that the effects may be mediated by aiding the export of excess acetyl groups from muscle or by enhancing uptake of octanoate into liver mitochondria.     

A new method for the surgical treatment of patients with paralysis of the tongue

Skeletal muscle biopsies from 18 children and 8 from their mothers were studied in mitochondrial myopathies. It is shown that by means of electron microscopy, histochemistry, and morphometry the correct diagnosis of mitochondrial insufficiency is quite possible.     

Muscular ultrasound in idiopathic inflammatory myopathies of adults

To evaluate the value of myosonography in inflammatory myopathies ultrasound of skeletal muscles was performed in 70 patients, aged 21-82 years, suffering from histologically proven polymyositis (n = 30), dermatomyositis (n = 18), granulomatous myositis (n = 9), inclusion body myositis (n = 13), and in 102 control persons. The sensitivity of muscle ultrasound in detecting histopathologically proven disease (82.9%) was not significantly different from electromyography (92.4%) or serum creatine kinase activity (68.7%). The positive predictive value of ultrasound was 95.1%, the negative predictive value 89.2%, and the accuracy 91.3%. The different types of inflammatory myopathies presented with typical, but not specific ultrasound features. Polymyositis showed atrophy and increased echointensity predominantly of lower extremity muscles, whereas in dermatomyositis clear muscle atrophy was rare and echointensities were highest in forearm muscles. Echointensities were lower in dermatomyositis compared to poly- and granulomatous myositis. Granulomatous myositis was characterized by the highest echointensities and a tendency towards muscle hypertrophy. Severe muscle atrophy was the most impressive feature in the majority of patients with inclusion body myositis. Comparison of ultrasound and histopathological findings indicates that muscle lipomatosis has a much greater impact on muscular echointensity than does muscle fibrosis. Ultrasound of myositis improved clinical assessment of patients by supplying differential diagnostic clues based on precise muscle size measurements and identification of mesenchymal abnormalities, particularly muscle lipomatosis.     

Infantile familial cardiomyopathy due to mitochondrial complex I and IV associated deficiency

Two brothers, aged 27 and 20 months, born from consanguineous healthy parents, presented with cardiomyopathy, lactic acidosis and carnitine abnormalities in serum and muscle, without clinical evidence of muscle involvement. The histochemical reaction for cytochrome c oxidase (COX) activity was negative in all muscle fibres, although the holoenzyme and subunits were present at a normal level, as shown by immunocytochemistry. The COX activity was, respectively, 5 and 25% of control values, in muscle biopsies. Partial deficiency of complex IV was confirmed in fresh isolated muscle mitochondria from patient 2 and was associated with a defect of complex I. Patient 1 died at age 3 yr 6 months. Partial improvement of cardiomyopathy in patient 2 was obtained under carnitine therapy, but seizures occurred and CT scan and magnetic resonance imaging (MRI) revealed thalamic hypodensity. Thus, the disorder appears to be progressive despite the clinical stabilization of the cardiomyopathy. This further demonstrates the complexity and clinical heterogeneity of combined respiratory chain complex deficiencies.     

Refining hollow obturator base using light-activated resin

Inclusion body myositis (IBM) is a separate class of the inflammatory myopathies with recently proposed clinical and pathological diagnostic criteria. An association between inflammatory myopathies and malignancy has been questioned in the literature. Recent reviews of the inflammatory myopathies suggest that only dermatomyositis is associated with malignancy. The largest study to date of patients with IBM found that 15% had a malignancy (6 of 40). We report the first documented case of IBM and concurrent transitional cell carcinoma of the bladder. We suggest that a causal relationship between IBM and malignancy may exist because of significantly improved functional strength gained after tumor removal.     

Hypoglycaemia in spinal muscular atrophy

Repeated episodes of hypoglycaemia were observed in two girls with spinal muscular atrophy. During a 12 h fast blood glucose fell to 3.4 and 2.7 mmol/L, respectively. One girl developed hypoglycaemia and ketonuria. Reduced gluconeogenesis was probably the cause of hypoglycaemia in these patients who had a muscle mass of about 10% of bodyweight (normal 30-40%). Hypoglycaemia must be suspected and treated when patients with severe muscle wasting due to chronic neuromuscular disorders are admitted comatose. In our experience this condition is often regarded as respiratory insufficiency.     

A functional bipartite nuclear localisation signal in the cytokine interleukin-5

In this study, clinical, histopathological and immunological profiles were analysed in ten patients with inflammatory myopathies. Polymyositis and dermatomyositis were more common than other forms of inflammatory myopathies. The pathogenetic mechanisms and distinguishing histopathological and immunological profiles between polymyositis and dermatomyositis have been highlighted.     

Successful treatment by direct hemoperfusion of coma possibly resulting from mitochondrial dysfunction in acute valproate intoxication

PURPOSE: We evaluated the efficacy of direct hemoperfusion (DHP) for treatment of acute valproate (VPA) intoxication and speculate on the biochemical perturbations that suggest a mechanism of coma induced by VPA overdose. PATIENT AND METHODS: The comatose patient was hospitalized approximately 6 h after ingesting 18 g VPA. DHP, with 200 g activated charcoal, was performed for 6 h. The plasma concentrations of VPA and Glasgow coma scale scores after admission were estimated. Before and after DHP, urine samples were tested in serial fashion for VPA metabolites, organic acids, and acyl carnitine esters of fatty acids. RESULTS: Plasma VPA was efficiently adsorbed on activated charcoal. The patient's plasma concentration of VPA decreased from 471 microg/ml (2,830 microM) to 45 microg/ml (270 microM), at which point the patient became alert. The half-life (t1/2) of VPA was calculated as 4.4 h before DHP and as 1.8 h during DHP. Before DHP, lactate and VPA-glucuronide markedly increased in urine samples, but beta-keto-VPA, a major mitochondrial metabolite, was not detected. Urinary excretion of carnitine esters of medium chain (C8-C10) dicarboxylic acids was increased. After DHP, lactate and VPA-glucuronide decreased, but a significant amount of beta-keto-VPA was demonstrated. Carnitine esters of medium chain dicarboxylic acids were decreased. CONCLUSIONS: DHP with activated charcoal was effective treatment for the patient with acute VPA intoxication and coma. The onset of coma may have been related to inhibition of beta-oxidation in the mitochondria, which was reversible by elimination of plasma VPA by DHP.     

Liver failure associated with mitochondrial DNA depletion

BACKGROUND/AIMS: Liver failure in infancy can result from several disorders of the mitochondrial respiratory chain. In some patients, levels of mitochondrial DNA are markedly reduced, a phenomenon referred to as mitochondrial DNA depletion. To facilitate diagnosis of this condition, we have reviewed the clinical and pathological features in five patients with mitochondrial DNA depletion. METHODS: Cases were identified by preparing Southern blots of DNA from muscle and liver, hybridising with appropriate probes and quantifying mitochondrial DNA relative to nuclear DNA. RESULTS: All our patients with mitochondrial DNA depletion died of liver failure. Other problems included hypotonia, hypoglycaemia, neurological abnormalities (including Leigh syndrome) and cataracts. Liver histology showed geographic areas of fatty change, bile duct proliferation, collapse of liver architecture and fibrosis; some cells showed decreased cytochrome oxidase activity. Muscle from three patients showed mitochondrial proliferation, with loss of cytochrome oxidase activity in some fibres but not in others; in these cases, muscle mitochondrial DNA levels were less than 5% of the median control value. The remaining two patients (from a single pedigree) had normal muscle histology and histochemistry associated with less severe depletion of mitochondrial DNA in muscle. CONCLUSIONS: Liver failure is common in patients with mitochondrial DNA depletion. Associated clinical features often include neuromuscular disease. Liver and muscle histology can be helpful in making the diagnosis. Mitochondrial DNA levels should be measured whenever liver failure is thought to have resulted from respiratory chain disease.     

Degradative activity of granzyme A on skeletal muscle proteins in vitro: a possible molecular mechanism for muscle fiber damage in polymyositis

The importance of cytotoxic T lymphocytes (CTLs) in the autoimmune inflammatory myopathies, especially polymyositis (PM), has been emphasized. We have studied the degradative activity of granzyme A, a cytotoxic molecule with trypsin-like specificity in CTL granules, on several muscle proteins in vitro. Our study reveals that granzyme A hydrolyzes dystrophin, myosin, and nebulin, but not laminin, alpha-actinin, vinculin, and connectin in vitro. Among these proteins, nebulin is more susceptible to proteolysis, followed by dystrophin, myosin heavy chain, and myosin light chains, in that order. This result implies an important role of granzyme A in CTL-mediated muscle fiber damage in PM.     

Cardiac involvement in neuromuscular diseases

Many neuromuscular disorders involve the heart, occasionally with overt clinical disease. Muscular dystrophies (dystrophinopathies, limb girdle muscular dystrophy, Emery-Dreifuss muscular dystrophy, Steinert's myotonic dystrophy), congenital myopathies, inflammatory myopathies and metabolic diseases (glycogenosis, periodic paralysis, mitochondrial diseases) may produce dilated or hypertrophic cardiomyopathy and heart rhythm or conduction disturbances. Furthermore the heart is commonly involved in some hereditary and degenerative diseases (Friedreich's ataxia and Kugelberg-Welander syndrome) and acquired (Guillain-Barré syndrome) or inherited (Refsum's disease and Charcot-Marie-Tooth syndrome) polyneuropathies. A cardiologist's high clinical suspicion and a simple but systematic skeletal muscle and peripheral nerve investigation, including muscle enzymes quantification, neurophysiological study and muscle biopsy, are necessary for an accurate diagnosis. In selected patients, more sophisticated biochemical and genetic analysis will be necessary. In most cases, endomyocardial biopsy is not essential for the diagnosis.     

Different mechanism may underlie respiratory failure of myotonic and Duchenne muscular dystrophies--a pulseoxymetric and spirometric study

Respiratory failure is an important cause of death in many neuromuscular diseases. We studied the relationship between nocturnal hypoxemia and respiratory muscle weakness by nocturnal pulseoxymetry and spirometry in two major hereditary myopathies, myotonic and Duchenne muscular dystrophies (MD and DMD respectively). In DMD significant nocturnal periodic hypoxemia appears only in cases with vital capacity lower than 20% of its expected value, suggesting that % vital capacity is a useful index of early respiratory failure. In contrast there was no correlation between vital capacity and severity of hypoxemia in MD patients. Therefore, we conclude respiratory muscle weakness is a single important factor which determines the severity of respiratory failure in DMD, while another/other factor (s), such as disturbance of respiratory control or myotonia, may play an important role in MD.     

Acquired carnitine abnormalities in critically ill children

In order to characterize the role of carnitine during metabolic stress, we prospectively determined carnitine profiles in plasma and urine on admission, days 2, 5, 10 and 15, among 28 critically ill children free of any known conditions associated with secondary carnitine deficiency. More than 25% of plasma and 50% of urinary carnitine measurements were abnormal; 96% (27/28) of patients displayed on at least one occasion an abnormal [< -2 SD or > +2 SD] carnitine value in plasma. Three children had extremely low [< 10 micromol/l] free carnitine (FC) levels in plasma. Plasma esterified and FC levels on admission were not related to the risk of mortality [PRISM score], to muscle lysis [CK values], and to the caloric intake. Levels of FC and esterified carnitine in plasma were unrelated to those measured in urine. Conclusion: Abnormal plasma and urine carnitine measurements are frequently found in critically ill children; the biological significance of these perturbations remains unclear. Caution must be exercised before concluding that an abnormal carnitine value is indicative of an underlying hereditary metabolic disorder in this population.     

Inflammatory myopathies and systemic disorders: a review of immunopathogenetic mechanisms and clinical features

The inflammatory myopathies are a heterogeneous group of muscle diseases characterized by muscle degeneration mediated by inflammatory processes. They may be idiopathic, as in polymyositis, dermatomyositis and inclusion body myositis, or associated with systemic disorders such as malignancies, overlap syndromes, and retroviral infection. The pathogenesis of each disease is discussed together with more recent molecular and cellular immunology findings. Salient diagnostic, clinical and pharmacological features are also reviewed.     

Fasciotomy, chronic venous insufficiency, and the calf muscle pump

OBJECTIVE: To test the hypothesis that fasciotomy may impair the function of the calf muscle pump, which in turn could result in the development of chronic venous insufficiency. DESIGN: A cohort study of patients with a history of lower extremity fasciotomy. SETTING: An urban trauma center. PATIENTS: Seventeen of the 83 patients identified through trauma, vascular, and/or orthopedic registries consented to participation in this study. INTERVENTIONS: Participating patients completed a study questionnaire, and then underwent a complete vascular examination, including air plethysmographic (APG) assessment. Patients with a history of venous injuries were also studied with color flow duplex venous imaging. MAIN OUTCOME MEASURES: Function of the calf muscle pump as measured by APG, and evidence of chronic venous insufficiency as measured by APG, findings on clinical examination, and by venous ultrasonography. RESULTS: Seventeen patients completed the study, including 8 with a history of vascular injuries, 6 with old fractures, and 3 who had undergone fasciotomy for soft tissue infections. The time from injury to examination ranged from 5 months to 20 years. Eight patients had signs or symptoms of venous insufficiency, the severity of which appeared to be time dependent. The APG data showed significant mean differences between fasciotomy and control extremities in ejection fraction (P<.001) and residual volume fraction (P<.001), both measures of calf muscle pump function. There were no significant changes in venous filling index, a measure of venous reflux, or in outflow fraction, which correlates with venous obstruction. There were no differences in APG variables between patients with vascular injuries vs those with orthopedic or soft tissue injuries. CONCLUSIONS: Lower extremity fasciotomy impairs long-term calf muscle pump function, as measured by APG, in patients with and without vascular injuries. These patients are at risk for the long-term development of chronic venous insufficiency following lower extremity trauma.     

Long-term mechanical ventilation in amyotrophic lateral sclerosis

BACKGROUND: Acute respiratory insufficiency (ARI) with alveolar hypoventilation or incapacitating dyspnoea but without peripheral muscle involvement can be an early manifestation of respiratory involvement in amyotrophic lateral sclerosis (ALS). Some of these patients benefit from assisted ventilation. The object of this study was to analyse the results of long-term mechanical ventilation (LTMV) in ten patients with ALS. METHODS: A retrospective analysis of intensive care unit (ICU) or ambulant patients with ALS who underwent LTMV in a conventional hospital ward was performed. Erect and supine spirometry, blood gas analysis and pulse oximetry were performed before the start and during the course of ventilation. RESULTS: Ten patients on LTMV were included. Four from the ICU were ventilated via tracheostomy, and six ambulant patients had non-invasive (nasal) ventilation. In all cases, ventilation was performed in a conventional hospital ward. The ambulant patients improved symptomatically during ventilation, confirmed by measurement of gas exchange and of SaO2 by continuous pulse oximetry. Three of the ten patients survive in long-term care--two with nasal and one with tracheostomy ventilation. CONCLUSIONS: LTMV outside ICU was possible in ten patients, seven of whom returned home. Returning home is very difficult for patients dependent on a ventilator who lack family support.