Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human thymomas and thymus hyperplasias were examined for retroviruses. Most of these patients were complicated by systemic immunological diseases such as myasthenia gravis and pure red cell aplasia. The thymus cells were co-cultured with allogenic B cells or peripheral blood lymphocytes (PBL) pretreated with mitomycin C. Retrovirus-like particles were demonstrated in cultured thymus cells in all cases of thymomas and thymus hyperplasias examined by electron microscopy. In most cases, these particles were detected in thymus epithelial cells. Reverse transcriptase activity sedimenting at a density of 1.15-1.17 gm/cm3 in sucrose density gradients was eluted in the culture fluids. Retrovirus-like particles were demonstrated in human T cells infected with these particles. Antibodies to virus-infected T cells were detected in sera of the patients with thymoma and thymus hyperplasia. These results suggest that in thymomas and thymus hyperplasias, retroviruses that can be induced, following a proliferative stimulus, may be involved in the genesis of thymic disorders and in the pathogenesis of systemic immunological diseases.
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PMID:RNA tumor virus in human thymomas and thymus hyperplasias. 241 38

A central role of the thymus in autosensitization to the acetylcholine receptor has been proposed to explain the immunopathogenetic processes in myasthenia gravis (MG). Two isoforms of the alpha-subunit of the acetylcholine receptor are known; they differ by a 25-amino-acid insertion coded by the P3A exon. We investigated the expression of the P3A exon by RNA polymerase chain reaction in fetal and adult human myoblasts and TE671 cells; both isoforms were expressed. Muscle biopsies from patients with MG, Duchenne muscular dystrophy, and polymyositis were also studied and it was again found that both isoforms were expressed, indicating that the P3A exon is not associated with autoimmune, degenerative, and inflammatory muscle diseases. When P3A expression was studied in thymus samples from normal subjects and from thymectomized MG patients, the P3A+ subunit was absent in 75% of patients with involuted thymus and in all patients with thymomas but was present in normal thymuses and in patients with hyperplasia. Differential expression of the alpha-subunit isoforms of the acetylcholine receptor within the thymus may play a role in the immune pathogenesis of MG.
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PMID:Acetylcholine receptor alpha-subunit isoforms are differentially expressed in thymuses from myasthenic patients. 900 49

Treatment-related chronic myeloid leukaemia (CML) is a less commonly recognised entity. It differs from treatment-related acute leukaemias in frequency, clinical course, and prognosis. Previously two cases of CML have been described following treatment of myasthenia gravis associated with thymoma treated by thymectomy. We report a 25-yr-old man with myasthenia gravis without thymoma who developed CML, 68 months after thymectomy. Cytogenetic study showed translocation (9,22)(q34;q11) with 10% showing double Ph chromosome. Reverse-transcriptase polymerase chain reaction (RT-PCR) of peripheral blood demonstrated the presence of p210(BCR/ABL) with b3a2 transcripts. He was treated with hydroxyurea, and still remained in the chronic phase during the last 6 months of follow up. His myasthenic symptoms remained stable.
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PMID:Chronic myeloid leukaemia in a man with myasthenia gravis treated by thymectomy. 1236 14