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Results for “Skeletal muscle dysfunction”

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At least 127 records · Page 7Linked to original sources

PubMed1983

Esophageal abnormalities and dysphagia in polymyositis and dermatomyositis.

Structural or functional abnormalities of the distal esophagus were demonstrated by cineradiography in 14 of 16 patients with polymyositis or dermatomyositis who had been incompletely responsive to high dose corticosteroids and, in some cases, immunosuppressive therapy, or who had adverse effects associated with these therapies. These distal abnormalities occurred in the absence of proximal esophageal skeletal muscle dysfunction in 70% of patients, usually were more frequent with increasing disease duration, and were functionally similar to abnormalities reported in scleroderma. Symptomatic improvement occurred to some patients with administration of antacids and measures designed to decrease esophageal reflux, but improved esophageal symptoms did not correlate with improvement in the myositis. In 18 autopsy subjects with similar histories, distal esophageal smooth muscle atrophy and fibrosis occurred in only 1 and 2 cases, respectively. Of 5 in whom distal esophageal dysmotility had been documented ante-mortem, only 1 had fibrosis and none had smooth muscle atrophy. These findings suggest that factors other than fibrosis and muscle atrophy may contribute to distal esophageal dysmotility in polymyositis and dermatomyositis.

Adult↗

PubMed1987

Myoadenylate deaminase deficiency and forearm ischemic exercise testing.

Myoadenylate deaminase (MADA) deficiency has been associated with symptoms of postexertional aches, cramps, weakness, and skeletal muscle dysfunction. Measurement of plasma lactate and ammonia concentrations after forearm ischemic exercise has been suggested as a screening test for this disorder. We performed forearm ischemic tests on 3 patients with histochemically defined MADA deficiency and 13 healthy control subjects, in a standardized fashion. Our results demonstrated that subject effort and/or performance during the exercise portion of testing is a critical variable. In addition to lactate and ammonia, plasma purine compounds (adenosine, inosine, and hypoxanthine) were measured. The finding of decreased purine release after exercise in MADA-deficient patients compared with that in normal individuals increases the specificity of the test and supports the hypothesis that disordered purine metabolism occurs in MADA deficiency.

AMP Deaminase↗

PubMed1988

Progressive myotonia in foals resembling human dystrophia myotonica.

A severe and progressive neuromuscular disorder accompanied by clinical, electrophysiological, and pathological features resembling human dystrophia myotonica was observed in three foals. This disorder was apparent as early as 1 month of age and involved progressive skeletal muscle dysfunction, initially characterized by proximal muscle hypertrophy and hypertonicity with subsequent muscle stiffness, weakness, and atrophy. Multisystem involvement was manifested in one case by testicular hypoplasia, early cataract formation, and borderline glucose intolerance. Prolonged dimpling of these large rear-limb muscles was elicited by percussion. Myotonic discharges were identified by electromyography. Percussion dimpling and the typical myotonic discharges persisted after neuromuscular blockade. Distinctive histologic muscle changes included ring fibers, sarcoplasmic mass formation, variation in fiber diameter size, and internally positioned nuclei.

Animals↗

PubMed1994

Bi-weekly vincristine, epirubicin and methylprednisolone in alkylator-refractory multiple myeloma.

Nine patients with poor-prognosis, alkylator-refractory stage III multiple myeloma (MM) were treated with a 23-h continuous infusion (CI) of a compatible mixture of vincristine (VCR) and epirubicin (EPI) daily for 4 days along with a daily 1-h infusion of high-dose methyl prednisolone (MP) to total of 5 days (VEMP); cycles were repeated every 2 weeks when possible, usually on an outpatient basis. WHO grade 3 or 4 neutropenia and infection were the predominant toxicities encountered, necessitating some treatment delays and dose reductions. Two patients died during treatment. Peripheral neuropathy necessitated discontinuation of the VCR in six patients without obvious loss of efficacy of the regimen. Skeletal muscle dysfunction and cardiomyopathy did not occur; trivial ECG abnormalities occurred during a minority of infusions but were of indeterminate relationship to the chemotherapy. Confusion occurred in two patients; alopecia was frequent but reversible, and mild/moderate dyspepsia and stomatitis were common but easily managed. Eight patients achieved a partial response (PR); another patient experienced early death during his second cycle before response assessment. The median survival from the first VEMP administration was 9 months (range, 1-64 + months), the median response duration was 7 months (range, 1-64 + months). Two patients experienced responses too short to be clinically relevant (< or = 2 months). An analysis of weekly paraprotein estimations suggests that the intended bi-weekly cycle length may be optimal. Six of these nine patients derived major benefit from this bi-weekly regimen, which deserves further exploration.

Aged↗

PubMed1990

Structure and function of the respiratory system of the dystrophic hamster.

The BIO 14.6 dystrophic hamster has been used extensively over the past 30 years as an animal model in which to study the mechanisms responsible for the development of cardiomyopathy and skeletal muscle dysfunction associated with muscular dystrophy. More recently, structural and functional aspects of the respiratory system of this animal model have been investigated. This review summarizes our current knowledge of ventilation, lung morphometry and mechanics, the structure and function of the diaphragm, tracheal and pulmonary vascular smooth muscle, and pulmonary macrophages in the BIO 14.6 dystrophic hamster. We conclude that many aspects of the structure and function of the respiratory system of this hamster warrant further investigation, including the development of alveolar hypoventilation, the causes of pulmonary vascular hyporeactivity, and the potential contribution of abnormal pulmonary macrophages to the pathogenesis of life-threatening respiratory disease in muscular dystrophy.

Animals↗

PubMed1981

The neuropathology of rheumatoid disease.

Patients with active rheumatoid disease may develop encephalopathy, myelopathy, peripheral neuropathy, and myopathy through a variety of tissue mechanisms. Brain involvement is usually characterized by the formation of rheumatoid nodules or by the development of vasculitis or its complications, and there is evidence to suggest that the trapping of immune complexes within the choroid plexus may be important in pathogenesis. Structural damage to the spinal cord and lower brain stem, on the other hand, most commonly results from narrowing of the bony canal, leading either to direct compression of neural tissue or to compromise of its vascular supply. The appearance of peripheral neuropathy generally signifies the presence either of inflammatory epineurial arterial disease or entrapment by neighboring anatomical structures. Skeletal muscle dysfunction may be due to vasculitis, myositis, or denervation atrophy. Both systemic and local anatomical factors, therefore, are of importance in determining the manner in which different parts of the nervous system may be affected in rheumatoid disease.

Brain Diseases↗

PubMed2002

Chronic heart failure: an example of a systemic chronic inflammatory disease resulting in cachexia.

Chronic heart failure is no longer a mere cardiac entity, but involves several, initially adaptive and later detrimental, neurohumoral compensatory mechanisms. Peripheral manifestations of the disease, such as endothelial dysfunction, skeletal muscle changes, and disturbances in ventilatory control, are major determinants of symptoms. The independent prognostic value and the relevance of cachexia on morbidity of patients with chronic heart failure have only recently been recognised. Altered body composition in heart failure patients is reflected in the early loss of muscle tissue but affects all tissue compartments in case of cardiac cachexia. Recently, a new portfolio of biologically active molecules, termed cytokines, have been shown to play an important role in the development and progression of both cardiac and peripheral abnormalities. Similar to other chronic illnesses, covered in the remainder of this issue, a low-grade chronic inflammatory process may be of particular relevance in the development of tissue wasting in these patients. Whereas the presence of immune activation in chronic heart failure is now widely accepted, as well as the prognostic relevance of chronic inflammation, the site and the source of cytokine production remain the object of intense research. Although the inciting event is located in the heart, cross-talk between the myocardium on the one hand, and the immune system, peripheral tissues and organs on the other hand, will lead to the overproduction of proinflammatory cytokines and, inevitably, to their detrimental effects. The specific problems related to heart failure progression and inflammatory activation are described in this review.

Animals↗

PubMed2006

[Evaluation of pulmonary function in the elderly. Intergroupe Pneumo Gériatrie SPLF-SFGG].

Aging is associated with a progressive decrease in lung function. As a consequence of aging, individual's reserve is diminished, but this decrease is heterogeneous between individual subjects. Many factors are involved in the overall decline in lung function. The prevalence of asthma in the elderly is estimated between 6 and 10%. Mortality due to COPD is increasing, especially among older subjects. Older subjects are at an increased risk of developing chronic diseases such as Parkinson's disease, which can have consequences for lung function. Under-nutrition is also common in the elderly and can produce sarcopenia and skeletal muscle dysfunction. The presentation of respiratory disorders may differ in the elderly, especially because of a lack of perception of symptoms such as dyspnea. The impact of bronchodilatators or corticosteroids on respiratory function has not been studied in the elderly. Drugs usually used for the treatment of hypertension or arrhythmias, which are often observed with aging, can have pulmonary toxicity. There is no difference between functional evaluation in younger and older subjects but it is more difficult to find predicted values for older patients. Performing pulmonary function tests in older patients is often difficult because of a higher prevalence of cognitive impairment and/or poor coordination. When assessing pulmonary function in the elderly, the choice of tests will be depend on the circumstances, with the use of voluntary manoeuvres dependent on the condition of the patient.

Aged↗

PubMed1989

Effect of chronic ethanol ingestion on tissue RNA and blood flow in skeletal muscle with comparative reference to bone and tissues of the gastrointestinal tract of the rat.

1. The effects of feeding a diet containing ethanol as 36% of total calories for 4-5 weeks on muscle RNA content and blood flow was investigated in male rats weighing 150-250 g. Control animals were pair-fed the same diet in which ethanol was substituted by isocaloric glucose. 2. Chronic ethanol consumption reduced the capacity for type II (anaerobic, fast-twitch) fibre-rich skeletal muscles to synthesize protein as reflected by a decreased RNA/protein ratio. Type I (aerobic, slow-twitch) fibre-rich muscles were unaffected. 3. Ethanol feeding had no significant effect on cardiac output. Furthermore, the percentage of cardiac output to type I and type II fibre-rich muscles, bone and tissues of the gastrointestinal tract, i.e. stomach, small intestine and large intestine, was unaffected by ethanol consumption. Similarly, ethanol feeding had no effect on blood flow when it was calculated on the basis of tissue weight (ml min-1 g-1). 4. It was concluded that chronic ethanol feeding in the rat was associated with selective skeletal muscle dysfunction in the absence of changes in blood supply.

Alcoholism↗

PubMed1999

Botulinum toxin for spastic gastrointestinal disorders.

Botulinum toxin (BTX) is one of the most potent inhibitors of acetylcholine from nerve endings, and this accounts for its toxic properties as well as its therapeutic application in a variety of neuromuscular syndromes. This review focuses on the growing use of BTX in the so-called 'spastic' disorders of the gastrointestinal tract. These include achalasia, for which the short-term efficacy of the intrasphincteric injection of BTX has been well established. However, because of the chronicity of this condition, repeated injections of the toxin may be required at regular intervals. In contrast, the relatively short duration of action may be an advantage in disorders such as chronic anal fissure, where the benefit of this therapy has now been demonstrated in hundreds of patients. There are many other sphincteric and non-sphincteric syndromes in the gut for which the efficacy of this agent is being actively tested. These include non-cardiac chest pain, post-operative pylorospasm and sphincter of Oddi dysfunction. Skeletal muscle sphincters, such as the upper oesophageal sphincter or the external anal sphincter/puborectalis muscle, may also be targeted, with good effect. In some of these conditions, the local injection of BTX may serve as a useful therapeutic trial, facilitating the decision to institute more invasive forms of therapy. The cumulative short-term experience with BTX in the gut to date suggests that it is a relatively simple and safe therapy. The use of BTX represents a novel approach for gastrointestinal motility disorders, and the rapidly expanding list of successful applications holds promise for a more widespread use of similar agents in the future. Additional studies on long-term outcome are eagerly awaited.

Botulinum Toxins↗

PubMed1991

Metabolic myopathies.

The term metabolic myopathy refers to a heterogeneous group of conditions that have in common abnormalities of muscle energy metabolism that result in skeletal muscle dysfunction. Most recognized metabolic myopathies are considered primary, represent inborn errors of metabolism, and are associated with known or postulated defects that affect the ability of muscle fibers to maintain adequate ATP concentrations. Traditionally, these diseases are grouped into abnormalities of glycogen, lipid, purine, and mitochondrial biochemistry. This discussion reviews the basic metabolic pathways that regulate normal muscle function; recent observations involving glycogen storage diseases, carnitine deficiency states, and myoadenylate deaminase deficiencies; and lastly, newer techniques available to assess patients with myopathic disorders.

Humans↗

PubMed1995

Enzyme and muscle diseases.

Two distinct areas of development contribute to the importance of enzymology in skeletal muscle disease: the measurement of enzymes in serum as a diagnostic aid and the investigation of enzyme deficiencies as the cause of metabolic myopathy. Currently, serum enzyme measurement, particularly creatine kinase, is used to aid in the detection of suspected myopathy, to differentiate myopathy from neurogenic disease, to identify dystrophies at a preclinical stage, to detect female carriers of dystrophies, and to assess response to therapy. Metabolic myopathies are disorders of muscle energy production that result in skeletal muscle dysfunction. The biochemical basis of such disorders is often a specific single enzyme defect. The tremendous advances in the molecular genetics of such disorders has added remarkably to our understanding of the primary defects involved and possible heterogeneity displayed at the molecular level.

Animals↗

PubMed2001

Extrapulmonary effects of chronic obstructive pulmonary disease.

Although airflow obstruction is the most obvious and most studied manifestation of chronic obstructive pulmonary disease (COPD), it should not be overlooked that COPD, particularly in its later stages, is associated with many extrapulmonary features that contribute to the morbidity, reduced quality of life, and, possibly, mortality of this disease. We review here the literature on skeletal muscle dysfunction, osteoporosis, and weight loss in COPD, with particular attention to possible approaches to their management. Patients with COPD may also have other extrapulmonary effects such as hormonal abnormalities that could probably be corrected, but less is known about them. COPD, therefore, should be regarded as a systemic disorder. Its systemic manifestations should not be overlooked in the overall care of the patient, because there are important ways in which they can be addressed.

Adrenal Cortex Hormones↗

PubMed1991

Assessment of cardiac function by M-mode echocardiography in selenium-deficient phenylketonuric children.

Selenium (Se) deficiency is associated with cardiac and skeletal muscle dysfunction. Twenty well children aged 2-16 years (10 male) attending the Phenylketonuria (PKU) Clinic at the Royal Children's Hospital, Brisbane, had low Se levels (mean 0.29 +/- 0.02 s.e.m. mumol/L; normal range 0.56-1.16 mumol/L). Their myocardial function was assessed at rest and after exercise provocation by M-mode echocardiography in order to exclude occult left ventricular dysfunction. At rest, fractional shortening (FS) was normal (mean 38.1 +/- 1.1 s.e.m. %, n = 20). After exercise, FS increased significantly (P less than 0.001) from 37.6 +/- 1.4% to 44.3 +/- 1.2%, n = 12). This was associated with a significant rise (P less than 0.001) in heart rate (HR) from 77.3 +/- 3.1 beats/min to 125.8 +/- 5.2 beats/min (n = 12). The normal resting FS and normal increase in FS and HR with exercise is evidence against significant cardiac impairment in this group of Se-deficient children.

Adolescent↗

PubMed1988

Congenital muscular dystrophy with cerebellar atrophy.

Congenital muscular dystrophy (CMD) is a disorder which usually presents at birth with skeletal muscle dysfunction. Cases have been described with associated severe central nervous system (CNS) abnormalities, but usually the condition proceeds without CNS impairment, particularly in less severe cases. A 25-year-old patient is described with clinical and pathological features of CMD accompanied by cerebellar dysfunction, most likely the result of cerebellar atrophy. This patient is thought to have a benign variety of CMD with CNS involvement, and this report stresses the fact that CMD can be associated with minimal CNS abnormalities and have a benign course.

Adult↗

PubMed1986

Toxicity of parathyroid hormone in uremia.

The most significant complication of elevated parathyroid hormone (PTH) levels in uremia is the development of osteitis fibrosa cystica. The hormone also appears to play a role in soft-tissue and organ calcification, metabolic abnormalities (glucose, lipids), and electroencephalographic changes seen in uremic patients. Its role in the hematological abnormalities of uremia (anemia, bleeding) is controversial. A role for PTH in heart and skeletal muscle dysfunction in uremia has not been clearly established. Further studies are required to establish PTH as a "universal" toxin in uremia.

Anemia↗

PubMed1988

Burn injury to trunk of rat causes denervation-like responses in the gastrocnemius muscle.

Thermal injury results in dystropic changes in skeletal muscle and abnormal pharmacological responses to neuromuscular relaxants, each of which suggests a denervation-like phenomenon. In the rat thermal injury model we examined whether, as in denervation states, increases in nicotinic acetylcholine receptors (AChR) and hyposensitivity to d-tubocurarine (dTc) are found. While anesthetized, thermal injury was imposed to trunk only. At 10, 14, and 21 days after injury the effective doses of dTc for left gastrocnemius tension suppression to 95% of control tension (ED95) were 0.213 +/- 0.039, 0.305 +/- 0.070, and 0.214 +/- 0.032 mg/kg, respectively. These values were significantly higher (P less than 0.05) than control values (0.155 +/- 0.006 mg/kg). The AChR concentrations in the left gastrocnemius, quantitated by 125I-alpha-bungarotoxin binding, increased at 10, 14, and 21 days to 182 +/- 20% (P less than 0.001), 166 +/- 22% (P less than 0.03), and 164 +/- 18% (P less than 0.001) of control, respectively. AChR concentrations in the right gastrocnemius also increased subsequent to thermal injury. Changes in effective dose of dTc for 50 and 95% twitch suppression in the left gastrocnemius correlated significantly with changes in AChR concentrations for the same muscle (r = 0.73 and 0.81, P less than 0.001, respectively). This study confirms the hypothesis that the systemic effects of thermal injury include an increase in AChR at sites distant from thermal injury, which may account for the skeletal muscle dysfunction and aberrant responses to neuromuscular relaxants.

Animals↗

PubMed1998

Metabolic and hemodynamic responses of lower limb during exercise in patients with COPD.

Premature lactic acidosis during exercise in patients with chronic obstructive pulmonary disease (COPD) may play a role in exercise intolerance. In this study, we evaluated whether the early exercise-induced lactic acidosis in these individuals can be explained by changes in peripheral O2 delivery (O2). Measurements of leg blood flow by thermodilution and of arterial and femoral venous blood gases, pH, and lactate were obtained during a standard incremental exercise test to capacity in eight patients with severe COPD and in eight age-matched controls. No significant difference was found between the two groups in leg blood flow at rest or during exercise at the same power outputs. Blood lactate concentrations and lactate release from the lower limb were greater in COPD patients at all submaximal exercise levels (all P < 0.05). Leg D02 at a given power output was not significantly different between the two groups, and no significant correlation was found between this parameter and blood lactate concentrations. COPD patients had lower arterial and venous pH at submaximal exercise, and there was a significant positive correlation between venous pH at 40 W and the peak O2 uptake (r = 0.91, P < 0.0001). The correlation between venous pH and peak O2 uptake suggests that early muscle acidosis may be involved in early exercise termination in COPD patients. The early lactate release from the lower limb during exercise could not be accounted for by changes in peripheral O2. The present results point to skeletal muscle dysfunction as being responsible for the early onset of lactic acidosis in COPD.

Acidosis, Lactic↗