Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C1762617 (weakness)
 37,932 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chronic respiratory failure is a major factor contributing to mortality in progressive neuromuscular disorders. Among the muscular dystrophies, respiratory failure most commonly occurs with Duchenne dystrophy, while in Becker, limb-girdle, and facioscapulo-humeral dystrophies, respiratory failure is infrequent and generally occurs in the more severe cases that have progressed to a nonambulatory, advanced functional stage. We report two brothers with a myopathic disease in which the distribution of weakness, initial clinical course, heredity, and muscle pathology most closely resembled a limb-girdle type of dystrophy. Both brothers, however, presented with chronic alveolar hypoventilation and respiratory failure when their locomotor disabilities were still mild. Respiratory failure was reversed, and satisfactory ventilation has been maintained for more than a year using a type of non-invasive intermittent positive pressure ventilation, with a bilevel positive airway pressure device (Bi-PAP), administered through a nasal mask during sleeping hours. These cases demonstrate an unusual presentation of limb-girdle dystrophy, and document that nocturnal, nasal administration of continuous airway pressure using the Bi-PAP device may be sufficient to maintain adequate long-term ventilation in some patients with neuromuscular causes of respiratory failure, and thus significantly improve quality of life and delay the need for more complex or invasive forms of assisted ventilation.
 ...
PMID:Chronic respiratory failure in limb-girdle muscular dystrophy: successful long-term therapy with nasal bilevel positive airway pressure. 806 62

We report a family with manifesting DMD carriers over two generations. Sixty years old female (case 1) suffered from slowly progressive weakness since her thirties. Her youngest daughter aged 30 (case 2) had cramping calf muscle pain since her 5 years old. Progressive muscle weakness developed and lost her ambulation by the age of 20. Grandson of case 1 (son of case 1's eldest daughter who has no clinical symptoms) was diagnosed as DMD with deletion of exon 19-21 in dystrophin gene. Case 1 and case 2 were revealed to be DMD carriers. We speculate that, in this family, X-inactivation process was not random and paternal X was preferentially inactivated by maternal mutant X.
 ...
PMID:[Manifesting carriers of Duchenne muscular dystrophy over two generations]. 810 23

The mechanism whereby dystrophin deficiency leads to excessive fibrosis and muscle degeneration is not known. The absence of dystrophin in skeletal muscle is associated with reduced plasma membrane stability as evidenced by elevated serum levels of the cytoplasmic enzyme creatine kinase. Basic fibroblast growth factor, a cytoplasmic polypeptide growth regulator that stimulates connective tissue synthesis, induces satellite cell proliferation, and suppresses myogenic differentiation, is made by skeletal muscle. We hypothesize that dystrophin deficiency leads to the constant release of basic fibroblast growth factor, which in turn contributes to fibrosis and muscle weakness by stimulating connective tissue and suppressing skeletal muscle differentiation. As an initial step in testing this hypothesis, we measured basic fibroblast growth factor in the serum of Duchenne muscular dystrophy patients. We found that whereas basic fibroblast growth factor was undetectable in the serum of normal individuals (n = 200), levels were elevated in 11 of 18 patients with Duchenne muscular dystrophy.
 ...
PMID:Elevated basic fibroblast growth factor in the serum of patients with Duchenne muscular dystrophy. 797 28

Duchenne muscular dystrophy (DMD) and murine X-linked muscular dystrophy (mdx) are genetically homologous and both characterized by absence of dystrophin. The function of this protein is not defined nor is the pathogenesis of the severe muscle necrosis and progressive weakness found in DMD but not in mdx. Recently we found that anionic phospholipid (AP) calcium binding sites are lacking at the muscle cell surface in DMD and we correlated these data with dystrophin deficiency and muscle necrosis. In order to verify the role of AP lack in the pathogenesis of muscle necrosis in DMD we studied the ultrastructural localization of these Ca++ receptors in mdx muscle membrane showing that they are normally represented as they are in control mouse and normal human muscle. The absence of AP in DMD compared with a normal distribution in mdx suggests that these calcium binding site alterations play an important and specific role in muscle fiber necrosis.
 ...
PMID:Anionic phospholipids calcium binding sites in Duchenne and murine X-linked muscular dystrophy. 815 77

Patients with Becker muscular dystrophy (BMD) have milder muscular impairment and better prognosis than patients with Duchenne muscular dystrophy (DMD). Another difference is that while cardiac failure due to myocardial involvement is a frequent cause of death in BMD, respiratory failure is the most common cause of death in DMD. We examined cardiac function and the mechanism of cardiac failure in 21 BMD patients aged 3 to 63 years (mean, 40.4) by electrocardiography, mechanocardiography, echocardiography, and post-mortem examination. Diagnosis of BMD was made by characteristic symptoms, dystrophic change in muscle histology, and the followings: 1) a deletion in the dystrophin gene, 2) "patchy" staining of dystrophin on immunocytochemical analysis, 3) abnormal dystrophin size on Western blotting, and 4) presence of a definite carrier in the family. To be diagnosed as BMD, patients exhibited one or more of 1)-3). Patients who were diagnosed only by 4) had a relative who had been diagnosed as BMD by one of 1)-3). The control group included 43 DMD patients (age 4-26 years, mean 16.2) and 20 healthy males (age 15-60 years, mean 33.3). Electrocardiogram showed prominent Q waves in leads II, III, aVF and V6, and tall R in V1, suggesting myocardial injury in the posteroinferior and lateral walls. The ratio of ejection time to pre-ejection period (ET/PEP) decreased to 2.0-3.3 in BMD, and was significantly lower than that in DMD patients with comparable muscle weakness. Left ventricular dilatation became more prominent with age, and end-diastolic left ventricular dimension (EDLVD) averaged 52.3 mm.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:[Clinical feature and mechanism of cardiac failure in patients with Becker muscular dystrophy]. 819 65

Dystrophin deficiency has been shown to be the underlying cause of Duchenne muscular dystrophy. Although dystrophin-deficient homologous animal models have been identified (dog, mouse, and cat), the clinical expression of the biochemical defect is species-specific. Thus, while the genetics and biochemistry of Duchenne dystrophy is understood, the pathophysiological cascade leading to muscle weakness in only humans and dogs remains obscure. To begin to dissect the pathophysiology at the histological level, we undertook a systematic study of mast cells in normal and dystrophin-deficient muscle. Mast cells have been implicated in the development of fibrosis in other disorders, and progressive fibrosis has been hypothesized to mediate the failure of muscle regeneration in human and dog dystrophin deficiency. Our results show a strong correlation between mast cell content and localization, and the clinico-histopathological progression in humans, dogs and mice. The mast cell increases were disease specific: other dystrophic myopathies with normal dystrophin generally did not show substantial increases in mast cell content or degranulation. Our data suggest that mast cell accumulation and degranulation may cause the grouped necrosis characteristic of dystrophin deficiency in all species.
 ...
PMID:A role for mast cells in the progression of Duchenne muscular dystrophy? Correlations in dystrophin-deficient humans, dogs, and mice. 819 2

Cardiomyopathy was reported in a few Duchenne muscular dystrophy (DMD) carriers with clinical evidence of myopathy. We report two carriers with dilated cardiomyopathy, increased serum CK, and no symptoms of muscle weakness. In heart biopsies of both patients, dystrophin-the protein product of DMD locus--was absent in many fibers. Dilated cardiomyopathy may be the only manifestation of dystrophin gene mutation in carriers.
 ...
PMID:Cardiomyopathy may be the only clinical manifestation in female carriers of Duchenne muscular dystrophy. 823 53

In a communication to the Royal Medical and Chirurgical Society of London in December 1851, which was published in the Transactions of the Society the following year, Edward Meryon, an English physician, described, in considerable detail, eight boys in three families with a disease later referred to as Duchenne muscular dystrophy. He was particularly impressed by the predilection for males and its familial nature, and that the progressive muscle wasting and weakness was essentially due to a disease of muscle and not the nervous system. His detailed histological studies revealed no abnormality of the spinal cord or nerves but in muscle tissue he noted extensive "granular degeneration" and in particular that the sarcolemma was broken down and destroyed. He appears to have been the first physician to make a detailed clinical, genetic, and pathological study of the disorder several years before Duchenne.
 ...
PMID:Duchenne muscular dystrophy--Meryon's disease. 826 22

The objective of this study was to compare the tibial structure and the strength of the tibia during muscle weakness and after recovery in mdx mice (which demonstrate X-linked muscular dystrophy and subsequent muscle regeneration) and age-matched control mice. The extent of disuse atrophy produced by muscle weakness and recovery following restoration of normal muscle strength could then be determined. The tibiae adjacent to weakened tibialis anterior muscles of 4-week-old mdx mice had significantly reduced radiographic density (p < 0.05) and cortical thickness (p < 0.001), and increased porosity (p < 0.001) compared to age-matched controls, suggesting development of disuse osteopenia. Significantly less force was required to break mdx tibiae than age-matched control tibiae (p < 0.05). In addition, Sharpey's fiber density was reduced (p < 0.001), suggesting a weakened attachment of the tibialis anterior muscle to bone. At 12 weeks, during the period of muscle regeneration, mdx tibial cortical thickness (p < 0.001) and porosity (p < 0.01) remained significantly lower, but percent calcium and Sharpey's fiber and radiographic densities were significantly greater (p < 0.001) than in age-matched controls, suggesting that bone mineralization and muscle attachment strength had increased to above normal levels in parallel with recovery of strength by the attached muscle. By 18 weeks, mdx tibial cross-sectional area, cortical thickness, and porosity remained significantly less (p < 0.001) than normal. Although Sharpey's fiber density was greater than in age-matched controls (p < 0.001) by 18 weeks, mdx tibial percent calcium (p < 0.005) and Sharpey's fiber density (p < 0.001) were significantly reduced from levels in 12-week-old mdx animals. There was significantly less deformation of the tibia prior to fracture in mdx than control tibiae at 18 weeks of age, suggesting tibial brittleness. Thus, at the site of attachment of mdx muscle to osteopenic bone, the remodelling which accompanies recovery of muscle strength is atypical, and produces an attachment of greater strength than function appears to require. These observations suggest that data are needed regarding bone mass and muscle-bone attachments in humans with disuse osteopenia, DMD, and other neuromuscular diseases.
 ...
PMID:Recovery from disuse osteopenia coincident to restoration of muscle strength in mdx mice. 827 5

In recent years, various clinical trials have documented the benefit of glucocorticoid therapy in the palliation of Duchenne muscular dystrophy (DMD). Prednisone therapy, daily or on alternate days, has been confirmed to be of value in enhancing muscle strength and function in DMD for up to two years. However, there is evidence that corticosteroid treatment results in muscle weakness and degeneration. This review, therefore, examines the available studies and addresses various possible mechanisms involved in the efficacy of prednisone therapy and amelioration of DMD. The progression of DMD is known to be associated with profound changes in structure, biochemistry and physiology of the affected muscles. It is hypothesized, therefore, that these very changes offer a fortunate set of circumstances, and it is owing to these alterations, as well as the well known anti-inflammatory/immunosuppressive action of steroid, that muscles in DMD are rendered responsive resulting in significant improvement of muscle bulk and function.
 ...
PMID:Corticosteroid therapy in Duchenne muscular dystrophy. 828 83


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>