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

Myasthenia gravis has variable effects on the respiratory system, ranging from no abnormalities to life-threatening respiratory failure. Studies characterized diaphragm muscle contractile performance in rat autoimmune myasthenia gravis. Rats received monoclonal antibody that recognizes acetylcholine receptor determinants (or inactive antibody); 3 days later, phrenic nerve and diaphragm were studied in vitro. Myasthenic rats segregated into two groups, those with normal vs. impaired limb muscle function when tested in intact animals ("mild" and "severe" myasthenic). Baseline diaphragm twitch force was reduced for both severe (P < 0.01) and mild (P < 0.05) myasthenic compared with control animals (twitch force: normal 1,352 +/- 140, mild myasthenic 672 +/- 99, severe myasthenic 687 +/- 74 g/cm2). However, only severe myasthenic diaphragm had impaired diaphragm endurance, based on significantly (P < 0.05) accelerated rate of peak force decline during the initial period of stimulation (0.02 + 0.02, 0.03 +/- 0.01, and 0.09 +/- 0.01%/pulse for normal, mild myasthenic, and severe myasthenic, respectively, during continuous stimulation) and intratrain fatigue (up to 30.5 +/- 7.4% intratrain force drop in severe myasthenic vs. none in normal and mild myasthenic, P < 0.01). Furthermore, compared with continuous stimulation, intermittent stimulation had a protective effect on force of severe myasthenic diaphragm (force after 2,000 pulses was 31.4 +/- 2.0% of initial during intermittent stimulation vs. 13.0 +/- 2.1% of initial during continuous stimulation, P < 0.01) but not on normal diaphragm. These data indicate that baseline force and fatigue may be affected to different extents by varying severity of myasthenia gravis and furthermore provide a mechanism by which alterations in breathing pattern may worsen respiratory muscle function in neuromuscular diseases.
 ...
PMID:Adverse effects of myasthenia gravis on rat phrenic diaphragm contractile performance. 1510 14

Myasthenia gravis (MG) is caused by T cell-dependent antibodies reactive with acetylcholine receptors. These autoreactive antibodies cause muscle weakness by interfering with neuromuscular transmission via removal of acetylcholine receptors from the neuromuscular junction as well as changing the architecture of the junction itself. Consequently, muscle fatigue is a debilitating aspect of MG often leading to more general feelings of tiredness not directly due to muscle weakness. We have previously described two peptides that are mimetics of antigen receptors on certain autoreactive T and B cells that are involved in MG. When used as vaccines in the rat model of MG, these peptides prevented and ameliorated disease and muscle fatigue by blunting acetylcholine receptor antibody responses. Such disease protection resulted from vaccine-induced anergizing antibodies against acetylcholine receptor-specific T and B cell antigen receptors. The present study prospectively evaluated the efficacy of these two vaccines in spontaneous acquired MG in pet dogs. When compared to historical controls that were prospectively studied, the vaccines increased the proportion of remitted dogs from 17 to 75%. In comparison to retrospectively studied historical controls that spontaneously remitted from MG, the vaccines accelerated the rate of decline in acetylcholine receptor antibody titers which resulted in a 3-fold decrease in the mean time to remission. These results are suggestive of a new type of targeted therapy that can drive autoimmune responses into long-term remission and possibly afford a means of determining whether correction of a physical cause of muscle weakness also corrects the perception of chronic, generalized fatigue.
 ...
PMID:Possible therapeutic vaccines for canine myasthenia gravis: implications for the human disease and associated fatigue. 1711 48

Myasthenia gravis (MG) is an organ-specific autoimmune disorder characterized by weakness and fatigue of voluntary muscles, and presence of autoantibodies to acetylcholine receptor of postsynaptic muscle membrane. A review of the international literature suggests that there is large variety of MG frequency and distribution. An annual incidence rate of MG is thought to be between 0.25 and 20 per 1,000,000 population. The prevalence of MG in world shows even wider variation, i.e. ranging from 50/1,000,000 in Hong Kong to 200/1,000,000 in Virginia (USA). Among population of Belgrade, an average annual incidence rate during the period 1983-1992 was 7.1/1,000,000, and prevalence on December 31, 1992 was 121.5/1,000,000. The mortality rate of MG is very low with value under 1/1,000,000. Epidemiological studies of MG have indicated trend of increasing MG prevalence with relatively stable incidence. This reflects the impact of effective treatment, improved diagnostic methods and prolonged survival. Due to development of intensive care facilities and immunomodulating treatment, the mortality of MG has significantly decreased. The most common age of MG onset is between 20 and 40 years. In this age group, about 60% of patients are women, while sex ratio at older age is 1:1. Stressful life events, viral infections, pregnancy and delivery may precipitate the development of MG. MG is associated with other autoimmune diseases in about 30% of cases. Although the number of patients with MG continues to rise, it is still a rare disease. Further epidemiological research with a view to establish population registries and to estimate economic impact of disease on population as well as quality of life of patients with MG is needed.
 ...
PMID:[Epidemiology of myasthenia gravis]. 1725 17

The aim of this study was to compare the clinically based prevalence of myasthenia gravis (MG) with the prevalence of laboratory-confirmed cases. All patients with a diagnosis of MG living in Estonia as on 1 January 1997 were asked to participate in re-examination. The criteria for laboratory-supported MG were weakness and rapid fatigue and a positive outcome of at least one of three laboratory tests: (i) blinded acetylcholinesterase inhibitor test; (ii) determination of antibodies to acetylcholine receptor and (iii) neurophysiological examination using repetitive nerve stimulation and single-fibre EMG. Eighty-nine patients were re-examined and 70 patients (79%) fulfilled the criteria of laboratory-supported MG. The corrected prevalence ratio was 78 per million. In the non-confirmed MG group, there was more women (92%) than men (43%) whose diagnosis was established within 1 year from onset of symptoms (P = 0.016). In all women with non-confirmed MG the diagnosis was established within 1 year from referral to the physician, whereas 68% of women with confirmed MG was diagnosed within 1 year (P < 0.0001). Thus, we conclude that, in Estonia the prevalence of MG based on medical records seems overestimated by 21% and women are at higher risk of obtaining an uncertain diagnosis of MG.
 ...
PMID:Clinical and laboratory-reconfirmed myasthenia gravis: a population-based study. 1819 May 10

Glycogen storage disease type Ib (GSD Ib, OMIM 232220) is an inborn disorder of glucose metabolism, caused by mutations in the G6PT gene, encoding a glucose 6-phosphate transporter (G6PT). GSD Ib is mainly associated with fasting hypoglycaemia and hepatomegaly. Most GSD Ib patients also show neutropenia and neutrophil dysfunction and therefore are at risk of developing severe infections and inflammatory bowel disease (IBD). An increased risk for autoimmune disorders, such as thyroid autoimmunity and Crohn-like disease, has also been demonstrated, but no systematic study on the prevalence of autoimmune disorders in GSD Ib patients has ever been performed. We describe a 25-year-old patient affected by GSD Ib who developed 'seronegative' myasthenia gravis (MG), presenting with bilateral eyelid ptosis, diplopia, dysarthria, severe dysphagia, dyspnoea and fatigue. The repetitive stimulation of peripheral nerves test showed signs of exhaustion of neuromuscular transmission, particularly evident in the cranial area. Even in the absence of identifiable anti-acetylcholine receptor antibodies, seronegative MG is considered an autoimmune disorder and may be related to the disturbed immune function observed in GSD Ib patients.
 ...
PMID:Myasthenia gravis in a patient affected by glycogen storage disease type Ib: a further manifestation of an increased risk for autoimmune disorders? 1843 26

Myasthenia gravis (MG) is a chronic neuromuscular disease which leads to varying degrees of weakness in the skeletal muscles. Some of the symptoms of the disorder include weakness of the eye muscles, difficulty in swallowing and slurred speech. When only the muscles of the eyes are affected, the illness is termed ocular myasthenia, which is often characterized by abrupt onset of diplopia and ptosis of the eyelid. In most patients with ocular-onset MG, there is a progression to involvement of other muscle groups within the first two years (generalized myasthenia). In the case reported here, a 39-year-old male of Ecuadorian descent complained of difficulty seeing, double vision, dizziness, unsteady gait, difficulty maintaining balance and fatigue for the previous two days. Neurological examination was remarkable for total external ophthalmoplegia. There was no external bulbar muscle paralysis, motor weakness, muscle wasting, sensory deficits or sphincter dysfunction. His laboratory workup was significant for elevated acetylcholine receptor antibody. He was diagnosed with ocular MG after differential diagnoses were ruled out based on the onset and presentation of symptoms, the patient's age and a normal magnetic resonance imaging exam. No signs of generalized myasthenia were detected. His symptoms improved dramatically after treatment with Acetyl cholinesterase (AchE) inhibitors and steroids, regaining much of his ocular mobility and ability to walk without gait imbalance. At follow-up visits, the patient remained healthy with no evidence development of other myasthenic signs. This case is atypical since ocular MG does not normally occur in the absence of other myasthenic forms.
 ...
PMID:An atypical course of myasthenia gravis. 1860 52

Disorders affecting the postsynaptic side of the neuromuscular junction include autoimmune myasthenia gravis (MG) as well as some of the congenital myasthenic syndromes (CMS). Lambert-Eaton myasthenic syndrome (LEMS) is an acquired autoimmune neuromuscular disorder in which autoantibodies are directed against the presynaptic calcium channels. Here we describe two monozygous twin brothers: case 1 was diagnosed with an indeterminate form of acquired postsynaptic neuromuscular junction defect at age 32 and case 2 with LEMS at age 47. Case 1 presented clinically with mild generalized myasthenic weakness, neurophysiological examination revealed disturbed neuromuscular transmission along with probable myositis and serum analysis regarding antibodies against the acetylcholine receptor and muscle-specific tyrosine kinase was negative. Case 2 presented with proximal muscle fatigue accompanied by areflexia at rest and antibodies against the P/Q-type voltage-gated calcium channels were present. Neurophysiologically, case 2 had reduced baseline compound motor action potential amplitudes on neurography, decrement on low-frequency repetitive nerve stimulation (RNS) and pathological increment on high frequency RNS. To our knowledge this is the first case report of its kind and adds an intriguing contrast to the more common diagnosis of CMS in monozygous twins.
 ...
PMID:Monozygous twins with neuromuscular transmission defects at opposite sides of the motor endplate. 1868 14

A female in her late 60s with chronic kidney disease was admitted to the emergency department with complaints of dizziness four days prior to hospitalization. Cibenzoline (300 mg/day) was administered for atrial fibrillation, which was detected in an electrocardiogram. After three days, she experienced blepharoptosis and was admitted for suspected myasthenia gravis. However, the anti-acetylcholine receptor antibody and edrophonium tests were negative. On day four after hospitalization, she suffered from pneumonia with pleural effusion and she was put on a respirator for four days. From day 16 after hospitalization, she had diarrhea and her renal function worsened. At the same time, a gradual aggravation of right blepharoptosis, dull headache, weakness and difficulty in chewing were noted. She experienced dyspnea on day 31 after hospitalization. Chest X-ray film did not show a pneumonia shadow or pleural effusion, and arterial blood gases revealed hypercapnia; she was diagnosed as having CO2 narcosis due to respiratory muscle fatigue and was put on a respirator again. Myasthenia-like syndrome was suspected because of a probable overdose of cibenzoline and administration of cibenzoline was withdrawn. Her condition improved and she was taken off the respirator on day 35 after hospitalization. Repetitive stimulation of 5 Hz was applied to her right facial nerve along with evoked electromyogram(EMG) on days 2 and 11 after discontinuing cibenzoline. On day 2, the EMG showed a waning phenomenon, whereas no such phenomenon was seen on day 11. The blood concentration of cibenzoline immediately after withdrawal was extremely high (2448 ng/mL). When this drug is administered to a patient with chronic kidney disease, attention must be paid to the indication, dose, and manifestation of the possible side effects.
 ...
PMID:[Myasthenia-like syndrome induced by cibenzoline overdose in a patient with chronic kidney disease]. 1906 53

Coexistence of myasthenia gravis with an immunologically mediated neuropathy syndrome is rare. We present a young male patient with a history of generalized muscle weakness and fatigue with electrophysiological evidence of both a motor neuron syndrome and a neuromuscular junction abnormality accompanied by pathologic evidence of denervation with muscle biopsy. Laboratory evidence for both acetylcholine receptor (AchR) antibodies and anti-asialo GM1 antibodies, both of high levels, was found. The patient's fatigue and weakness showed an objective response to pyridostigmine, prednisone, and immunoglobulin therapy over a period of 9 months.
 ...
PMID:Coincident Acetylcholine Receptor Antibody and Anti-Asialo GM1 Antibody in a Young Male. 1907 28

Myasthenia gravis (MG) is an autoimmune disorder usually caused by antibodies against either the acetylcholine receptor (AChR) or muscle-specific tyrosine kinase (MuSK) at the neuromuscular junction. Neuromuscular transmission failure results in muscle fatigue and weakness that can be treated symptomatically with acetylcholinesterase inhibitors (AChEIs). Long-term treatment with nonselective AChEIs may have considerable drawbacks; thus, this medication is ideally tapered when strength improves. Patients with AChR antibodies respond beneficially to treatment, whereas patients with MuSK antibodies generally do not. Recently, the selective AChEI EN101, which specifically targets the isoform of "read-through" AChE (AChE-R), has been developed and may be of importance for symptomatic relief in AChR-antibody seropositive MG. This article is a review of the mechanisms, therapeutic effects, and drawbacks, with both old and new AChEIs in MG.
 ...
PMID:Acetylcholinesterase inhibitors in MG: to be or not to be? 1926 48


<< Previous 1 2 3 4 5 6 7 Next >>