Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

X-linked dystrophinopathy is the most common cause of isolated cases of myopathy in males. To investigate dystrophin abnormalities as a cause of myopathy in girls and women, we used dystrophin immunocytochemistry to study muscle biopsies from 505 girls and women with neuromuscular disease. Forty-six muscle biopsies showed a combination of fibers containing or lacking dystrophin; this mosaic immunostaining pattern denoted a carrier status. Twenty-one of 46 (45.6%) had a family history of Duchenne muscular dystrophy in males. Twenty-five of 46 (54.3%) were isolated cases, with no previous family history of neuromuscular disorder. The laboratory findings of the isolated cases were consistent with the familial cases; all showed myopathic histopathology and abnormal elevations of serum CK. The clinical presentations of the isolated cases varied but were consistent with the familial cases: 40% (10/25) of isolated cases showed proximal limb weakness before age 10, 24% (6/25) presented with myalgias or cramps, 24% (6/25) presented with incidental findings of grossly elevated CK levels, 8% (2/25) noted easy fatigue, and 4% (1/25) had slowly progressive proximal limb weakness beginning at age 45. From our data, the clinical criteria for consideration of an underlying dystrophinopathy in isolated female cases of myopathy are CK levels greater than 1,000 IU/l and myopathic histopathology. About 10% of the isolated cases of hyperCKemic myopathy (25/210) were proven by dystrophin analysis to have a dystrophinopathy as the cause of their disease (manifesting carriers of Duchenne dystrophy). However, we feel that this may be an underestimate. The correct diagnosis in these patients is imperative for appropriate genetic counseling to the patients and their families.
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PMID:Dystrophinopathy in isolated cases of myopathy in females. 157 51

We present 17 patients with advanced DMD who required long-term assisted ventilation. Eleven patients used part-time assisted ventilation. Five of the patients received BV and/or M-IPPV or N-IPPV between two and nine years before requiring full-time T-IPPV, while six others initially used part-time T-IPPV. One patient used all three modes before requiring full-time T-IPPV. Mean (+/- SD) FVC and rebreathe PCO2 at the outset of assisted ventilation were 0.62 +/- 0.20 L and 47.4 +/- 7.5 mm Hg, respectively. Clinical features were divided between symptoms suggesting respiratory muscle fatigue and sleep-related disordered breathing. We found that, while useful in early respiratory insufficiency, BV is associated with recurrent aspiration. In our experience, N-IPPV offers the safest and most convenient form of noninvasive ventilation. When the VC has decreased to about 300 ml, most patients will require full-time ventilation; T-IPPV is advised to provide airway access to suction secretions.
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PMID:Decline in respiratory function and experience with long-term assisted ventilation in advanced Duchenne's muscular dystrophy. 218 99

To evaluate the therapeutic possibilities of chronic electrical stimulation, muscle function studies and quantitative tests of physical assessment were used to monitor the response of quadriceps femoris to prolonged low frequency stimulation. Comparative studies of the maximum voluntary and electrically elicited responses of muscles of young ambulant children with Duchenne muscular dystrophy, when compared to those of normal children's muscles, revealed lower values of maximum voluntary contraction, significant slowing (P less than 0.001) of mean relaxation times and a higher resistance to fatigue testing. Intermittent chronic low frequency stimulation resulted in a significant (P less than 0.01) increase in mean maximum voluntary contraction of the stimulated muscles compared with the mean force exerted by the unstimulated control muscles. There are clear therapeutic possibilities for the use of chronic low frequency stimulation in these children.
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PMID:Therapeutic possibilities of chronic low frequency electrical stimulation in children with Duchenne muscular dystrophy. 232 68

The effect of chronic low frequency stimulation on the tibialis anterior muscle of children with Duchenne muscular dystrophy was investigated. Baseline data from 16 boys established low values of maximum voluntary contraction which did not improve with age. Studies of the contractile properties revealed significant slowing (p less than 0.001) of mean relaxation time compared to that of normal children's muscles. There was no loss of force during fatigue testing, as in normal children, but in contrast to normal children, there was no potentiation at lower frequencies of stimulation. Intermittent chronic low frequency stimulation of muscles in six young ambulant children with Duchenne muscular dystrophy resulted in a significant increase (p less than 0.05) in mean maximum voluntary contraction compared with the mean forces exerted by the unstimulated control muscles of the contralateral leg.
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PMID:Responses of muscles of patients with Duchenne muscular dystrophy to chronic electrical stimulation. 349 92

We used a 4-minute sustained maximum voluntary contraction to investigate fatigability of the anterior tibial muscle in eight healthy boys and 11 boys with Duchenne muscular dystrophy (DMD) (ages 5 to 10 years). Before exercise, the force generation of dystrophic muscle and the compound muscle action potential amplitude were lower and half-relaxation time of the tetanus was longer in patients than in controls. During exercise, the decline in tetanic force and potentiation in twitch tension were similar in both groups. However, during exercise, there was less decline in maximum voluntary contraction and less added force in DMD patients, suggesting that there was less central fatigue in patients than in controls. Thus, patients with DMD and controls have similar intramuscular fatigability and excitation-contraction coupling, and central activation in patients is functioning as well as or better than in healthy controls.
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PMID:Muscular fatigue in Duchenne muscular dystrophy. 785 31

The dystrophin-deficient, X-linked dystrophic mouse (mdx) was used to evaluate the efficacy of prednisolone treatment. A test protocol was used to take advantage of the quantifiable weakness and disability as well as molecular genetic defect shared with the X-linked Duchenne muscular dystrophy (DMD). Whole-body weakness and fatigue were determined by non-invasive force-transducer physiographic and variable-speed treadmill techniques, respectively. Other measurements included hind-limb muscle protein, calcium, and histomorphology. Subcutaneously-administered prednisolone elicited significant improvements in whole body strength throughout a two-month test period. Increases in strength were also accompanied by measurable increments in running endurance. In fact, prednisolone treatment appeared to protect mdx mice from the stressful effect of continuous running as determined by strength and muscle fiber diameter. Test results from this study support the limited therapeutic benefit observed previously in DMD patients treated with the glucocorticoid.
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PMID:Strength and endurance in the therapeutic evaluation of prednisolone-treated MDX mice. 843 32

The purpose of this study was to investigate whether continuous infusion of an anabolic steroid, stanozolol, would alter skeletal muscle size and performance in sedentary male mice. The study was performed as a preliminary to an investigation on the effect of anabolic steroids on skeletal muscle regeneration in the mdx mouse, an animal model used for the study of Duchenne muscular dystrophy. Skeletal muscle structure and contractile behavior, and heart, liver, kidney, and testis wet weights were assessed after 3 or 6 wk of continuous exposure to one of two concentrations of stanozolol. Continuous release pellets containing either a high (1.5 mg) or low (0.5 mg) concentration of stanozolol were implanted into 8-wk-old C57BL/6J male mice. Control mice were implanted with pellets containing the drug vehicle. Stanozolol infusion had no significant effect on the contractile strength or mass of either fast-twitch extensor digitorum longus or slow-twitch soleus muscle. The resistance to fatigue of both muscles, assessed in vitro, was unaffected by stanozolol; however, postfatigue recovery of soleus twitch and tetanic tension after 3 wk of treatment was significantly (P < 0.05) increased in high-dose mice compared with control and low-dose mice. Androgen-sensitive muscles, bulbocavernosus and levator ani, were significantly (P < 0.05) increased in wet weight after 3 wk of stanozolol treatment, but were not significantly different from control muscles after 6 wk, suggesting that continuous infusion produced a tolerance to the drug. Similarly, heart wet weight was significantly (P < 0.05) increased in stanozolol-treated mice compared with control after 3 wk, but not after 6 wk. Testis wet weight was significantly (P < 0.05) decreased in low-dose mice compared with control mice at 3 wk, but not at 6 wk. Plasma testosterone concentration was not significantly different between any of the groups after 3 or 6 wk of treatment. This study suggests that in the absence of other factors (e.g., high-intensity exercise or other degenerative changes in muscle fibers), continuous infusion of an anabolic steroid produces no significant effect on the growth, contractile strength, or endurance of hindlimb skeletal muscles.
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PMID:Effect of continuous infusion of an anabolic steroid on murine skeletal muscle. 847 3

Myotonic dystrophy (MyD) patients have been reported to show severe nocturnal desaturation related to sleep respiratory disorders. However, the reason of respiratory failure in MyD has remained unclear. In this study, ten patients with MyD underwent overnight polysomnography to evaluate the mechanisms which would cause respiratory failure, compared with Duchenne muscular dystrophy (DMD) patients in these three views: 1) sleep-related nocturnal desaturation, 2) histopathological evaluation of respiratory muscles, and 3) abnormalities of respiratory center. Nocturnal desaturation was more prominent in MyD rather than DMD. Apnea-hypopnea index (AHI) was higher in MyD than DMD. Type of respiratory disorder during sleep was mainly central apnea-hypopnea pattern, including Cheyne-Stokes respiration. In histopathological findings, central core change in respiratory muscle related to respiratory muscle fatigue was found less frequently in MyD than DMD. In respiratory center function, MyD showed hyporesponse to both alveolar hypercapnic and hypoxic stimulation. However, DMD showed normal response to both stimulations. We concluded that respiratory failure in patients with MyD would be attributed to respiratory center disorder rather than respiratory muscle weakness, which is the main cause of respiratory failure in patients with DMD.
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PMID:[Respiratory failure: respiratory disorder during sleep in patients with myotonic dystrophy]. 875 39

This study is designed to analyse the behavior, in the sagittal plane, of a complete human dorso-lumbar rachis, made rigid by the posterior instrumentation used for the treatment of scoliosis, on subjects suffering from DMD (Duchenne Muscular Dystrophy). The object of this analysis is to demonstrate the reliability of early surgery made possible by new instrumentation. Close review of the literature shows that the currently used Harrington or Luque instrumentations lead to mechanical complications, especially rod breaking, at the thoraco-lumbar junction. 8 specimens were non-destructively tested in-vitro. Compression and flexion were applied. For each test, rachis movements with and then without instrumentation, and also rod restraints were noted. The results show a linear stiffness multiplied by 8.3 in flexion and 11.6 in extension. The maximum restraint recorded for physiological displacements is 77 MPa. This remains largely under the fatigue-breaking limit of the metal used (stainless steel hammer-hardened 316 L, Young's modulus = 200,000 MPa, Poisson's ratio = 0.21, endurance limit = 350 MPa at 5 x 10(6) cycles). The results of this study encourage us to continue and develop early surgery in children affected by myopathy, with fixation of the complete rachis, including a lumbo-sacral arthrodesis and a supple dorsal part of the mounting, in the sagittal plane.
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PMID:In-vitro biomechanical study of a dorso-lumbo-sacral posterior supple instrumentation with variable section. 893 35

31P NMR spectroscopy was used to study the energy metabolism of dystrophin-deficient skeletal muscle of mdx mice, an animal model of Duchenne muscular dystrophy, in which expression of a truncated form of utrophin has been obtained through transgenesis technology. Measurements of ATP, phosphocreatine (PCr), inorganic phosphates (Pi) and intracellular pH (pHi) were made at rest, during a fatigue protocol and during the subsequent recovery. Mechanical fatigue of transgenic muscles was similar to normal muscle, while mdx muscle showed larger force loss. At rest, muscles of all groups had similar values for [ATP], [PCr], [Pi] and pHi. During fatigue, [PCr] decreases mirrored [Pi] increases and were similar in all groups. The major difference between mdx muscles and the group of normal and trc-utrophin muscles concerned the values and evolution of pHi. The mdx muscles showed a more severe intracellular acidosis during exercise and a slower and incomplete post-exercise recovery of normal pHi. In contrast, in trc-utrophin muscles, the kinetics and amplitude of pHi changes were remarkably close to normal behaviour. We conclude that the impaired proton washout which is present in mdx muscles, is corrected to a great extent by the expression of trc-utrophin.
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PMID:Expression of truncated utrophin improves pH recovery in exercising muscles of dystrophic mdx mice: a 31P NMR study. 971 53


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