Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.1.8 (cholinesterase)
12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Twenty cases of failing transcervical thymectomy are reported. They were selected for transsternal re-exploration from a series of 95 patients who had previously undergone transcervical thymectomy because of myasthenia gravis (MG). A specific method for pre-operative detection of remnants of the non-tumorous thymic gland is lacking, but the applied clinical selection criteria were so far reliable: generalized, disabling, fluctuating MG despite cholinesterase inhibitor and/or immunosuppressive treatment, and no or inconsistent improvement after transcervical thymectomy. At transsternal re-exploration the commonest findings were intact lower thymic lobes with persistent venous drainage into the brachiocephalic vein. Presence of thymic tissue was histologically confirmed in all the excised specimens (weight range 10-60, mean 23 g), and the examination showed thymic hyperplasia in 18 cases, fatty involution of the gland in two, and a lympho-epithelial thymoma in one case. The re-operation was followed by objectively registrable improvement in all but one of the 20 patients during observation periods of 8-75 (mean 21) months. There was statistically significant reduction in disability scores (means 8.2-4.9) and in need for anticholinesterase medication (to 67% of pretreatment dose). Immunosuppression became unnecessary in 6 of 11 patients and could be reduced in 4 patients. The incidence of failure in transcervical thymectomy was alarmingly high (27%), and more re-operations are anticipated. Since the transcervical approach involves a high risk of incomplete thymectomy, its use should be abandoned. However, in most of the patients with re-operation, subsequent progress has been sufficiently promising for advocacy of sternotomy whenever the clinical criteria of failure are fulfilled.
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PMID:Failing transcervical thymectomy in myasthenia gravis. An evaluation of transsternal re-exploration. 652 69

A case of severe myasthenia gravis diagnosed in a 12-month-old girl is described. Thymectomy at 15 months of age had only a negligible effect on the course of the disease. Treatment with cholinesterase inhibitors, prednisolone and azathioprine was started. After one year of combined treatment she was symptomfree and 3 years later treatment with cholinesterase inhibitors and prednisolone was discontinued. Attempts to withdraw azathioprine have so far been unsuccessful, leading to relapse of the disease. IgG-antibodies against cholinergic receptors were lowered to near normal, whereas the levels of total plasma immunoglobulins remained normal. The proportion of T-lymphocytes in peripheral blood was reduced during the first weeks after thymectomy, but has since been normal. Lymphocyte function measured by PHA stimulation remained normal all the time. The girl grew and developed normally without complicating infectious diseases in spite of her severe disease, thymectomy and immunosuppressive treatment.
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PMID:Myasthenia gravis. Immunological studies in a young child treated with thymectomy and immunosuppressive drugs. 660 92

To investigate pathogenic mechanisms in experimental autoimmune myasthenia gravis (EAMG) and myasthenia gravis (MG), we studied the acute and chronic effects in rats of injection of rat monoclonal antibodies ( MCABs ) directed against the acetylcholine receptor (AChR). Animals were severely weak 12 h after a single injection, at which time macrophages were found invading endplate regions of muscle and cholinesterase-stained regions were separted from the underlying muscle fibers. Ultrastructural studies showed findings identical to the acute phase of EAMG: degenerating postsynaptic membranes and invasion and phagocytosis of endplate regions by macrophages. Animals receiving sublethal doses of MCAB recovered clinically by 4-5 days after injection. Recovery was accompanied by a progressive decrease in the number of macrophages associated with endplates and reapposition to the myofibers of the cholinesterase-stained regions. Animals injected once, or repeatedly over several months, remained clinically and electromyographically normal after recovery from the initial episode of weakness, but their endplate ultrastructure was highly simplified with blunted or absent synaptic folds and shallow or absent secondary synaptic clefts. These studies demonstrate that anti-AChR MCABs can induce the changes of both acute and chronic EAMG. There is good correlation between the inflammatory changes and the acute clinical disease but poor correlation between morphological and clinical parameters in the chronic syndrome. The latter observation suggests that severe ultrastructural changes, similar to those seen in chronic EAMG and MG, cannot account, at least in rats, for the clinical and electrophysiologic abnormalities of MG.
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PMID:Induction of the morphologic changes of both acute and chronic experimental myasthenia by monoclonal antibody directed against acetylcholine receptor. 661 Feb 75

During a 42-month period, we used plasmapheresis to treat four cases of myasthenia gravis with refractory respiratory failure. All four patients were ventilator dependent for prolonged periods and were not responding to management with cholinesterase inhibitors and corticosteroids. All four patients rapidly responded to the plasmapheresis; respiratory muscle strength returned sufficiently to allow discontinuation of assisted mechanical ventilation and removal of the artificial airway. In our experience, plasmapheresis is indicated in the treatment of the myasthenia gravis patient with respiratory failure which is refractory to conventional drug therapy.
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PMID:Plasmapheresis in the treatment of ventilator-dependent myasthenia gravis patients. Report of four cases. 672 82

In 13 Smooth Fox Terriers with a congenital form of myasthenia gravis, clinical signs included intermittent, progressive muscle weakness that became more pronounced with exercise; muscle wasting; megaesophagus; and aspiration pneumonia. Neurologic abnormalities were apparent only during periods of weakness and included inability to retract the fore- and hindlimbs from painful stimuli. A decrement of the compound muscle action potential was evident during repetitive supramaximal nerve stimulation. Intravenous injection of a short-acting cholinesterase inhibitor evoked immediate improvement of clinical and electromyographic signs. Intracellular microelectrode studies of a biopsied external intercostal muscle revealed reduced amplitude of miniature end-plate potentials, as occurs in acquired myasthenia gravis. However, in contrast to acquired myasthenia gravis, antibodies directed against acetylcholine receptors were not demonstrable in serum and were not bound to acetylcholine receptors in muscle. Despite lack of complexing with immunoglobulin, the amount of acetylcholine receptor protein in biopsied external intercostal muscles from 9 affected pups was less than 25% of the amount in 5 unaffected littermates. The latter finding accounted for the reduction in amplitude of miniature end-plate potential and the failure of neuromuscular transmission. Treatment with a long-acting cholinesterase inhibitor in 6 cases resulted in temporary improvement in muscle strength.
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PMID:Congenital myasthenia gravis in 13 smooth fox terriers. 684 Dec 51

Over a 10-year period 12,643 gynecologic surgical procedures were performed with the patients under general anesthesia. Succinylcholine was the muscle relaxant used in the majority of cases. Four of these patients developed prolonged postoperative apnea; the longest period of apnea was 6 hours. In one patient atypical cholinesterase was documented, and two of the patients were subsequently diagnosed as having myasthenia gravis. In the fourth case an etiology for the apnea was not demonstrated. A compilation of drugs in common clinical usage which interfere with neuromuscular transmission is included.
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PMID:Prolonged postoperative apnea complicating gynecologic surgery; atypical cholinesterase and myasthenia gravis. 708 10

Myasthenia gravis is characterized by variable ocular and skeletal muscle weakness. Peak incidence is in young women and older men. Thymomas are present in 30 percent of myasthenic patients over age 40. Binding of acetylcholine receptors by IgG antibodies may be the mechanism of the neuromuscular disorder. Repetitive nerve stimulation (Jolly test), provocative tests with quinine or curare and the edrophonium test (cholinesterase inhibition) are the diagnostic maneuvers employed.
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PMID:The neuromuscular junction. Part II: myasthenia gravis. 745 20

A patient developed a severe cholinergic syndrome from the use of echothiophate iodide ophthalmic drops, presented with profound muscle weakness and was initially given the diagnosis of myasthenia gravis. Red blood cell and serum cholinesterase levels were severely depressed and symptoms resolved spontaneously following discontinuation of the eye drops.
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PMID:Cholinergic toxicity resulting from ocular instillation of echothiophate iodide eye drops. 765 Jul 71

Cholinesterases form a family of serine esterases that arise in animals from at least two distinct genes. Multiple forms of these enzymes can be precisely localized and regulated by alternative mRNA splicing and by co- or posttranslational modifications. The high catalytic efficiency of the cholinesterases is quelled by certain very selective reversible and irreversible inhibitors. Owing largely to the important role of acetylcholine hydrolysis in neurotransmission, cholinesterase and its inhibitors have been studied extensively in vivo. In parallel, there has emerged an equally impressive enzyme chemistry literature. Cholinesterase inhibitors are used widely as pesticides; in this regard the compounds are beneficial with concomitant health risks. Poisoning by such compounds can result in an acute but usually manageable medical crisis and may damage the CNS and the PNS, as well as cardiac and skeletal muscle tissue. Some inhibitors have been useful for the treatment of glaucoma and myasthenia gravis, and others are in clinical trials as therapy for Alzheimer's dementia. Concurrently, the most potent inhibitors have been developed as highly toxic chemical warfare agents. We review treatments and sequelae of exposure to selected anticholinesterases, especially organophosphorus compounds and carbamates, as they relate to recent progress in enzyme chemistry.
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PMID:Anticholinesterases: medical applications of neurochemical principles. 772 78

We describe the effect of repeated suxamethonium doses during propofol-fentanyl-N2O/O2 anaesthesia in a 29-year-old woman with active myasthenia gravis receiving chronic pyridostigmine therapy. Despite adequate pre-operative pseudocholinesterase activity, suxamethonium resistance occurred. Neither bradycardia nor residual neuromuscular block were seen after repeated doses of suxamethonium.
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PMID:Response to suxamethonium during propofol-fentanyl-N2O/O2 anaesthesia in a patient with active myasthenia gravis receiving long-term anticholinesterase therapy. 801 95


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