Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An outbreak of subcutaneous tumors in young layer chickens in a flock in Japan was investigated. Tumors appeared as extensive swelling or bulbous protrusions of the integument and were observed in the head or wing of chickens approximately 9 wk old, with a prevalence of 0.4% (157 of 42,000) in the affected flock. Histologically, two types of tumor were observed: myxoma containing abundant hyaluronic acid and neurofibroma with hyperplasia of the Herbst corpuscles. Ultrastructurally, type C retroviruses, such as viral particles, were found in the tumors. The tumors were specifically stained by immunohistochemistry using monoclonal antibodies against the subgroup A avian leukosis/sarcoma virus (ALSV) and yielded a positive reaction to primers specific for subgroup A ALSV by reverse transcriptase-polymerase chain reaction assay. The virus was isolated from the tumors. Seventeen of 20 clinically normal chickens in the affected flock showed antibodies against ALSV. These results suggest that subcutaneous tumors are associated with subgroup A ALSV infection.
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PMID:An epizootic of subcutaneous tumors associated with subgroup A avian leukosis/sarcoma virus in young layer chickens. 1566 79

Although somatostatin receptors have been detected in many normal and neoplastic tissues, little is known of their expression and function in peripheral nerve tumors. In the present study, we examined the expression of all 5 somatostatin receptor subtypes (sst1-5) in 3 normal peripheral nerves, 3 traumatic neuromas, 27 schwannomas, 18 neurofibromas, and 177 malignant peripheral nerve sheath tumors (MPNSTs) by immunohistochemistry as well as by Western blot and reverse transcriptase-polymerase chain reaction investigations in 2 normal peripheral nerves, one neurofibroma, 5 schwannomas, and 5 MPNSTs. Immunoreactive somatostatin receptors were not detectable in normal peripheral nerve and in nonneoplastic Schwann cell proliferations. In contrast, sst2A mRNA and protein was present in 89% of schwannomas. This receptor subtype was less frequently detected in neurofibromas (22%) and MPNSTs (15%). Interestingly, sst4 was seen in 32% of MPNSTs and was almost exclusively expressed in this malignant tumor type. In support of a role in Schwann cell tumor growth control by somatostatin was the observation of induced internalization of sst2A and inhibition of cell proliferation in an NF1-associated MPNST cell line. Moreover, administration of an sst2A-selective agonist resulted in induction of MPNST cell apoptosis. We conclude that peripheral nerve sheath tumors often express at least one functional somatostatin receptor. Furthermore, our findings suggest a potential clinical role for somatostatin receptor agonists in tumor imaging and/or treatment of schwannomas and MPNSTs.
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PMID:Expression and function of somatostatin receptors in peripheral nerve sheath tumors. 1631 18