1/37. myasthenia gravis, thymoma, intestinal pseudo-obstruction, and neuronal nicotinic acetylcholine receptor antibody.intestinal pseudo-obstruction occurs rarely in patients with myasthenia gravis (MG) and thymoma. The etiology of the intestinal pseudo-obstruction remains to be elucidated, although an autoimmune mechanism is postulated. We present the first report of neuronal nicotinic acetylcholine receptor (AChR)-specific antibody in a patient with seropositive MG, malignant thymoma, and intestinal pseudo-obstruction. This finding provides evidence that intestinal pseudo-obstruction associated with thymoma and possibly other neoplasms may be related to antibodies against the neuronal nicotinic receptors at autonomic ganglia.- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
2/37. Myasthenia, thymoma, presynaptic antibodies, and a continuum of neuromuscular hyperexcitability.BACKGROUND: autoantibodies specific for the nicotinic acetylcholine receptor (AChR) of skeletal muscle impair neuromuscular transmission in myasthenia gravis (MG). autoantibodies specific for alpha3 neuronal AChRs or voltage-gated potassium channels have been reported in patients with isaacs syndrome, an acquired disorder of continuous muscle fiber activity characterized by neuromyotonia. OBJECTIVE: To report the neuromuscular autoantibody profiles of three patients with a syndrome of MG and neuromuscular hyperexcitability. RESULTS: All three patients reported here had clinical and electrophysiologic evidence of MG and neuromuscular hyperexcitability. None had neuromyotonia. thymoma was proven in two patients and suspected in the third. One had MG and thymoma and subsequently developed cramp-fasciculation syndrome; MG and rippling muscle syndrome appeared simultaneously in the other two. All patients had muscle and neuronal AChR binding antibodies and striational antibodies. Only one had antibodies reactive with alpha-dendrotoxin-complexed potassium channels. CONCLUSIONS: The coexistence of cramp-fasciculation syndrome and acquired rippling muscle syndrome with MG, thymoma, and neuronal AChR autoantibodies suggests that there is a continuum of autoimmune neuromuscular hyperexcitability disorders related pathogenically to isaacs syndrome. Manifestations of neuromuscular hyperexcitability may be altered and less apparent in the context of MG because of the coexisting defect of neuromuscular transmission.- - - - - - - - - - ranking = 0.40144190164982keywords = complex (Clic here for more details about this article) |
3/37. lambert-eaton myasthenic syndrome with ophthalmoparesis and pseudoblepharospasm.We report a patient initially diagnosed as having ocular myasthenia gravis who showed progressive ophthalmoparesis and pseudoblepharospasm together with positive acetylcholine receptor antibodies. Repeated evaluation with high-frequency repetitive stimulation revealed an incremental response and elevated titers of antibodies against presynaptic calcium channels, confirming lambert-eaton myasthenic syndrome. Systemic evaluation revealed no malignant neoplasm but revealed euthyroid Hashimoto's disease. Immunomodulative therapy including plasma exchange and administration of an immunosuppressent (azathioprine) combined with a potassium-channel blocker (3,4-diaminopyridine) reduced the ocular abnormalities. We conclude that the ocular manifestations in this patient were probably caused by lambert-eaton myasthenic syndrome.- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
4/37. Coexistence of epilepsy, myasthenia gravis and psoriasis vulgaris.We report the case of a 36-year-old Chinese man with a history of complex partial seizure of temporal lobe origin since the age of 12 years, superimposed by myasthenia gravis since the age of 27 years and psoriasis vulgaris since the age of 29 years. With an eight-year follow-up, the above three diseases remained without complete remission. Anticonvulsant therapy (phenytoin and trimethadione) caused drug-induced myasthenia gravis, which should gradually disappear after discontinuing the drugs. However, the myasthenic symptoms and serum acetylcholine receptor antibody persisted following the discontinuation of phenytoin in our patient. myasthenia gravis and psoriasis are both autoimmune diseases and correlate with specific human histocompatibility antigens. This suggests a close connection between these two diseases. The coexistence of epilepsy, myasthenia gravis and psoriasis vulgaris has not been previously reported, and to the best of our knowledge, our patient is the first reported case. The relationship among these three diseases requires further investigation.- - - - - - - - - - ranking = 0.40144190164982keywords = complex (Clic here for more details about this article) |
5/37. Studies of human myasthenia gravis: electrophysiological and ultrastructural evidence compatible with antibody attachment to acetylcholine receptor complex.Neuromuscular junctions from patients with early onset and chronic myasthenia gravis were examined by electrophysiological and ultrastructural techniques. acetylcholine (AcCh) sensitivities were reduced by 34-63% in early onset myasthenia and 60-80% in chronic myasthenia. Ultrastructural analysis revealed that virtually all junctional folds of the early onset patients were intact but that the AcCh-receptor-rich crests of these folds were uniformly covered by an attached layer of 30 X 70 A particles arranged in small tufts or rosettes. In chronic myasthenic endplates, however, junctional fold crests were destroyed, apparently being replaced by vesicular membrane debris similarly labeled by tufts of 30 X 70 A particles. Thus, the initial reduction in junctional AcCh sensitivity observed in early onset myasthenia gravis may be attributed at least in part to in situ masking or inactivation of AcCh receptors, whereas the marked decrease in AcCh sensitivity observed in the chronic myasthenic patient may represent a combination of two factors: (a) in situ masking of AcCh receptors and (b) destruction of the receptor-containing crests of the junctional folds. These observations are compatible with an autoimmune etiology of myasthenia gravis initially involving an apparent antibody attachment to one or more components of the functional AcCh receptor complex, followed by systematic destruction and removal of junctional folds by both humoral and cell-mediated autoimmune responses.- - - - - - - - - - ranking = 2.0072095082491keywords = complex (Clic here for more details about this article) |
6/37. Mesangial proliferative glomerulonephritis with deposits of anti-nicotinic acetylcholine receptor antibody in a patient with myasthenia gravis.A patient with myasthenia gravis developed nephrotic syndrome 3 years after thymectomy. The kidney biopsy specimen revealed mesangial proliferative glomerulonephritis with immune deposits. The glomerular mesangial cells and tubular epithelial cells were sensitive to alpha-bungarotoxin (alpha-BT), a ligand for nicotinic acetylcholine receptor (nAChR), and the binding was inhibited by native alpha-BT, as well as other nAChR ligands, nicotine and d-tubocurarine. In addition, FITC-alpha-BT-neuromuscular junction complexes could also bind to the mesangial cells, and preincubation with unlabeled nAChR inhibited the binding. These findings are consistent with the notion that both nAChR-like protein and anti-nAChR antibody are present in t he mesangial cells of the patient. Although the pathogenetic role of anti-nAChR antibody on the development of glomerulonephritis is unclear, the present observations provide an important insight into the autoimmune-mediated pathophysiological relationship between myasthenia gravis and mesangial proliferative glomerulonephritis.- - - - - - - - - - ranking = 0.40144190164982keywords = complex (Clic here for more details about this article) |
7/37. myasthenia gravis and lymphoblastic lymphoma involving the thymus: a rare association.myasthenia gravis (MG) is an autoimmune neuromuscular junction disease. An association between thymic epithelial neoplasms and MG is well known. However, it is rarely associated with hematologic malignancies. In particular, very few cases of lymphoblastic lymphoma involving the thymus and MG have been reported. Here we report a case T-cell lymphoblastic lymphoma involving the thymus who developed MG after the initial diagnosis. The patient initially presented with a mediastinal mass which was diagnosed as lymphoblastic lymphoma. MG was diagnosed during leukemic relapse in this patient and was based on clinical presentation and neurophysiologic studies including single fiber electromyography (EMG) and repetitive nerve stimulation tests. In contrast to the other cases with such an association, the myasthenic symptoms presented nine months after the diagnosis of lymphoma by thymectomy. The patient had a highly aggressive clinical course and was resistant to various chemotherapy regimens.- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
8/37. Follicular dendritic cell tumor of the mediastinum.Follicular dendritic cell tumor (FDT) is a rare neoplasm usually occurring in the laterocervical lymph nodes, but presentations elsewhere are also well documented. We report a case of FDT in a 48-year-old man with myasthenia gravis, in whom a slow-growing mediastinal mass that had been surgically excised manifested after 3 years with a local recurrence in the same site. The lesion was aspirated and cytology showed a tumor composed of groups of oval or elongated cells intermingled with several mature small lymphocytes. On histology, the tumor was highly cellular with abundant perivascular lymphocytic infiltration; large cells with pale, eosinophilic cytoplasm and round nuclei, arranged in fascicles often showed a storiform pattern. Occasional binucleated cells were also present. A panel of antibodies showed positivity only for CD21 and CD35, and a weak response to S-100. Electron microscopy showed that the layer cells had convoluted nuclei and elongated interdigitating processes with desmosome-like junctions. The definitive diagnosis of FDT can be concluded only with positive immunostaining for CD21 and CD35. However, in the presence of a mixed population of lymphocytes and larger eosinophilic cells the hypothesis of FDT should always be considered.- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
9/37. Respiratory chain complex-I defect mimicking myasthenia.In a 67-year-old woman with ptosis, double vision, dysphagia, ambiguous Tensilon tests, normal acetylcholine-receptor antibodies, normal thymus, and repeatedly abnormal responses to low-frequency repetitive stimulation, ocular myasthenia was suspected. Pyridostigmin was ineffective, but corticosteroids improved the abnormalities. Despite this therapy, lower-limb weakness developed. Reevaluation disclosed abnormal increase of serum lactate during slight exercise, myogenic electromyography, ragged-red fibers, reduced oxidative enzyme staining and abnormally shaped and structured mitochondria on muscle biopsy, and a respiratory chain complex-I defect on biochemical investigation of the muscle homogenate. Respiratory chain disorder due to complex-I defect with abnormal decremental response to low-frequency repetitive stimulation was diagnosed. It is concluded that respiratory chain disorders due to a complex-I defect may mimic ocular myasthenia clinically, electrophysiologically, and even therapeutically.- - - - - - - - - - ranking = 2.8100933115488keywords = complex (Clic here for more details about this article) |
10/37. Epithelio-reticular cell thymoma with lymphocytic "emperipolesis." An ultrastructural study.The ultrastructure of an epithelio-reticular cell thymoma associated with myasthenia gravis is described. The neoplastic cells of an epithelio-reticular nature were dominant in the neoplasm, being closely associated with lymphocytes and scattered non-neoplastic macrophages. The thymic epithelio-reticular cell showed abundant glycogen and some lipid droplets inside the cytoplasm, which was vacuolated and had many elongated processes attached to desmosomes and a very prominent nucleolus. The appearance was similar to that of the immature embryonic epithelial cell of the thymus seen in mammals. Very close contacts existed between the thymic lymphocytes and the epithelio-reticular cells, the appearance being suggestive of the phenomenon of "emperipolesis." cell death occurred secondarily through nuclear pyknosis and chromatolysis. Lymphocytic debris appeared inside the epithelio-reticular cells and, to some extent, in the cytoplasm of the mesenchymal marcrophages not directly involved in the phenomenon of "emperipolesis."- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
| | Next -> |