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:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

On the basis of reports demonstrating possible roles for leukocyte function-associated antigen 1 (LFA-1) and intercellular adhesion molecule 1 (ICAM-1), the ligand for LFA-1, in human immunodeficiency virus type 1 (HIV-1) infection, we have explored the involvement of the ICAM-1 molecule by using selected synthetic peptides derived from the protein sequence. Replication was assessed in MT-2 cells, highly susceptible to HIV infection, in the presence of four synthetic peptides derived from the ICAM-1 amino acid sequence. This cell type was chosen for the ability to form marked syncytia on infection with cell-free virus. Under the conditions used, minimal or no cytotoxicity was observed with the peptides up to concentrations of 50 micrograms/ml. A peptide corresponding to a unique region of ICAM-1, JF9 [ICAM-1(367-394, A-378)], had little effect on virus replication despite its ability to inhibit cell-cell adhesion. In contrast, an N-terminal peptide, JF7B [ICAM-1(1-23)], consistently inhibited virus replication in MT-2 cells in a dose-dependent manner, as measured by cell-free reverse transcriptase (RT) activity (up to 70% inhibition), soluble virus antigen production (up to 60% inhibition), and syncytium formation (virtually complete inhibition up to 6 days post infection). Testing of W-CAM-1 antibody, and anti-ICAM-1 antibody that inhibits cell-cell adhesion, revealed no significant inhibitory effects on RT activity, virus antigen production, and syncytium formation in HIV-1-infected MT-2 cells at a level that markedly inhibited cell-cell adhesion (10 micrograms/ml).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Synthetic peptide analogs of intercellular adhesion molecule 1 (ICAM-1) inhibit HIV-1 replication in MT-2 cells. 810 34

Didanosine (ddI) that inhibits the reverse transcriptase of human immunodeficiency virus (HIV) causes steatosis and fulminant hepatitis in some patients with HIV. We studied hepatic histopathologic changes with particular attention to ddI-induced Mallory body formation. Three liver biopsies were performed on three patients with HIV who were treated with ddI; an autopsy was performed on a patient with HIV who was also treated with ddI. All hepatic specimens were studied with a routine liver immunohistochemical panel including antibodies to ubiquitin and cytokeratin (CAM 5.2). Morphologically, all hepatic specimens showed focal to diffuse steatosis with a predominance of macrovesicular fatty change. Fibrosis was minimal in three cases. No secondary bacterial and fungal infections were noted. Single or clusters of "empty cells" were present, and some contained Mallory bodies validated by ubiquitin stain. Empty cells are hepatocytes that fail to stain positive for cytokeratin. The Mallory bodies were different from the others because they were randomly distributed and occurred in noncirrhotic hepatic tissue. In the autopsy specimen, the Mallory bodies had a centrilobular location with central fibrosis (central sclerosing hyaline necrosis).
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PMID:2',3'-Dideoxyinosine-induced Mallory bodies in patients with HIV. 929 55

Mutations in the type VII collagen gene, COL7A1, give rise to the blistering skin disease, dystrophic epidermolysis bullosa. We have developed two new mutation detection strategies for the screening of COL7A1 mutations in patients with dystrophic epidermolysis bullosa and compared them with an established protocol using conformational sensitive gel electrophoresis. The first strategy consisted of an RNA based protein truncation test that amplified the entire coding region in only four overlapping nested reverse transcriptase-polymerase chain reaction assays. These fragments were transcribed and translated in vitro and analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. We have used the protein truncation test procedure to characterize 15 truncating mutations in 13 patients with severe recessive dystrophic epidermolysis bullosa yielding a detection sensitivity of 58%. The second strategy was a DNA-based fluorescent chemical cleavage of mismatch (fl-CCM) procedure that amplified the COL7A1 gene in 21 polymerase chain reaction assays. Mismatches, formed between patient and control DNA, were identified using chemical modification and cleavage of the DNA. We have compared fl-CCM with conformational sensitive gel electrophoresis by screening a total of 50 dominant and recessive dystrophic epidermolysis bullosa patients. The detection sensitivity for fl-CCM was 81% compared with 75% for conformational sensitive gel electrophoresis (p = 0.37 chi2-test). Using a combination of the three techniques we have screened 93 dystrophic epidermolysis bullosa patients yielding an overall sensitivity of 87%, detecting 79 different mutations, 57 of which have not been reported previously. Comparing all three approaches, we believe that no single method is consistently better than the others, but that the fl-CCM procedure is a sensitive, semiautomated, high throughput system that can be recommended for COL7A1 mutation detection.
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PMID:Comparative mutation detection screening of the type VII collagen gene (COL7A1) using the protein truncation test, fluorescent chemical cleavage of mismatch, and conformation sensitive gel electrophoresis. 1050 58

Primary cultures of intrahepatic bile duct epithelial (IBDE) cells isolated from duckling livers were successfully grown for studies of duck hepatitis B virus (DHBV). The primary IBDE cells were characterized by immunohistochemistry using CAM 5.2, a cytokeratin marker which was shown to react specifically to IBDE cells in duck liver tissue sections and in primary cultures of total duck liver cells. Immunofluorescence assay using anti-duck albumin, a marker for hepatocytes, revealed that these IBDE cultures did not appear to contain hepatocytes. A striking feature of these cultures was the duct-like structures present within each cell colony of multilayered IBDE cells. Normal duck serum in the growth medium was found to be essential for the development of these cells into duct-like structures. When the primary cultures of duck IBDE cells were acutely infected with DHBV, dual-labeled confocal microscopy using a combination of anti-DHBV core proteins and CAM 5.2 or a combination of anti-pre-S1 proteins and CAM 5.2 revealed that the IBDE cell colonies contained DHBV proteins. Immunoblot analysis of these cells showed that the DHBV pre-S1 and core proteins were similar to their counterparts in infected primary duck hepatocyte cultures. Southern blot analysis of infected IBDE preparations using a digoxigenin-labeled positive-sense DHBV riboprobe revealed the presence of hepadnavirus covalently closed circular (CCC) DNA, minus-sense single-stranded (SS) DNA, double-stranded linear DNA, and relaxed circular DNA. The presence of minus-sense SS DNA in the acutely infected IBDE cultures is indicative of DHBV reverse transcriptase activity, while the establishment of a pool of viral CCC DNA reveals the ability of these cells to maintain persistent infection. Taken collectively, the results from this study demonstrated that primary duck IBDE cells supported hepadnavirus replication as shown by the de novo synthesis of DHBV proteins and DNA replicative intermediates.
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PMID:Duck hepatitis B virus replication in primary bile duct epithelial cells. 1146 37

In small-cell lung carcinoma (SCLC) tumour cell contamination of leukaphereses is unknown. The present study was performed to define appropriate markers for reverse transcriptase polymerase chain reaction (RT-PCR), then to assess the contamination rate of leukaphereses and corresponding bone marrow samples. Immunocytochemistry (ICC) and RT-PCR methods were also compared. Among the 33 patients included, analyses were performed in 16 who had multiple leukaphereses and 17 who had only bone marrow. Leukapheresis products and bone marrow were analysed by ICC using several specific monoclonal antibodies against neural-cell adhesion molecule (N-CAM), epithelial glycoprotein (EGP-40) and cytokeratins (CK). Samples were also analyzed by RT-PCR for expression for N-CAM, synaptophysin, neuron-specific enolase, chromogranin, cytokeratin-18/-19, CEA, EGP-40, apomucin type 1 (MUC-1) and human endothelial cell-specific molecule (ESM-1). Using ICC staining, contaminating tumour cells were detected in 34% of leukaphereses (27% in patients with limited disease and 43% in those with extensive disease). N-CAM was the most reliable marker for detection of contamination. For RT-PCR, CK-19 and CEA were the only appropriate markers. Positive signal rate in leukaphereses increased to 78% (89% for patients with limited disease and 67% for extensive disease). In bone marrow, both techniques were in agreement whereas in leukaphereses, RT-PCR was better than ICC. A high rate of tumour cell contamination was demonstrated not only in bone marrow but also in leukaphereses from SCLC patients. The most appropriate technique was RT-PCR mainly in patients with limited disease.
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PMID:High tumour contamination of leukaphereses in patients with small cell carcinoma of the lung: a comparison of immunocytochemistry and RT-PCR. 1174 93

Curcumin (CCM; diferuoylmethane) is a dietary pigment in curry with known antineoplastic and anti-inflammatory effects. The immunosuppressive effects of CCM were studied in (1) rat heterotopic cardiac transplant models, using Brown-Norway (BN, RT1(n)) hearts to WKY (RT1(u)) hosts or Buffalo (BUF, RT1(b)) hearts to Wistar-Furth (WF, RT1(u)) hosts, (2) reverse transcriptase-polymerase chain reaction analysis of cytokines from transplanted specimens, and (3) mixed lymphocyte reactions (MLR). In the BN-to-WKY model, CCM alone significantly increased the mean survival time (MST) to 20.5 to 24.5 days, as compared to 9.1 days among nontreated controls. The combination of CCM and subtherapeutic doses of CsA produced further prolongation of the MST to 28.5 to 35.6 days, better than that of CCM or CsA alone (P <.05). In a BUF-to-WF model, CCM alone did not increased the MST, unless it was combined with subtherapeutic doses of CsA, wherein two thirds of the grafts survived for more than 60 days (P <.05 as compared to either treatment group). Cytokine analysis revealed significantly reduced expression of interleukin-2 (IL-2), interferon-gamma (IFN-gamma) and granzyme B in the day 3 specimens of the CCM and CCM CsA-treated allografts compared with the nontreated allograft controls. MLRs using the two MHC-incompatible rat strains (BNxWKY) showed an effect of increasing concentrations of CCM and/or CsA, which by combination index (CI) analysis showed a synergistic effect (CI = 0.22 to 0.81). This study for the first time demonstrates the effectiveness of CCM as a novel adjuvant immunosuppressant with cyclosporine both in vivo and in vitro.
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PMID:Curcumin enhances the immunosuppressive activity of cyclosporine in rat cardiac allografts and in mixed lymphocyte reactions. 1282 32

Mixed epithelial stromal tumor of the kidney (MEST)/adult cystic nephroma (CN) is a lesion characterized by epithelial lined tubular or cystic structures interspersed within a variably prominent, distinctive spindle-cell stroma. Although typically benign, cases with malignant features have been reported. Herein, we report a MEST/CN with malignant stromal features and rhabdoid differentiation arising in the left kidney of an 84-year-old woman. Histologically, the tumor displayed multiple tubules and variably sized cystic structures lined by benign epithelium with an intervening malignant-appearing spindle-cell stroma. The malignant stroma displayed condensation in the regions surrounding the epithelial component consistent with the ovarian-like stroma typically observed in MEST/CN. In addition, the stromal cells displayed extensive rhabdoid differentiation. Immunohistochemical analysis revealed strong expression of cytokeratin 7, CAM 5.2, AE1/AE3, wide-spectrum keratin, and epithelial membrane antigen by the epithelial component. The stromal component displayed strong immunohistochemical expression of WT-1, CD-99, CD-56, INI1, and estrogen receptor; focal actin positivity; and was negative for desmin, myogenin, and progesterone receptor. Analysis by reverse transcriptase polymerase chain reaction failed to identify the SYT-SSX1 or SYT-SSX2 fusion transcripts characteristic of synovial sarcoma. To our knowledge, this represents the first report in the literature of malignant MEST with rhabdoid features and suggests that this entity should be considered in the diagnosis of renal stromal malignancies with prominent rhabdoid features.
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PMID:Malignant mixed epithelial and stromal tumor of the kidney with rhabdoid features: report of a case including immunohistochemical, molecular genetic studies and comparison to morphologically similar renal tumors. 1770 62

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