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)

The TRUGENE HIV-1 Genotyping Kit and OpenGene DNA Sequencing System are designed to sequence the protease (PR)- and reverse transcriptase (RT)-coding regions of human immunodeficiency virus type 1 (HIV-1) pol. Studies were undertaken to determine the accuracy of this assay system in detecting resistance-associated mutations and to determine the effects of RNA extraction methods, anticoagulants, specimen handling, and potentially interfering substances. Samples were plasma obtained from HIV-infected subjects or seronegative plasma to which viruses derived from wild-type and mutant infectious molecular clones (IMC) of HIV-1 were added. Extraction methods tested included standard and UltraSensitive AMPLICOR HIV-1 MONITOR, QIAGEN viral RNA extraction mini kit, and QIAGEN Ultra HIV extraction kit, and NASBA manual HIV-1 quantitative NucliSens. Sequence data from test sites were compared to a "gold standard" reference sequence to determine the percent agreement. Comparisons between test and reference sequences at the nucleotide level showed 97.5 to 100% agreement. Similar results were obtained regardless of extraction method, regardless of use of EDTA or acid citrate dextrose as anticoagulant, and despite the presence of triglycerides, bilirubin, hemoglobin, antiretroviral drugs, HIV-2, hepatitis C virus (HCV), HBV, cytomegalovirus, human T-cell leukemia virus type 1 (HTLV-1), or HTLV-2. Samples with HIV-1 RNA titers of >or=1,000 copies/ml gave consistent results. The TRUGENE HIV-1 Genotyping Kit and OpenGene DNA Sequencing System consistently generate highly accurate sequence data when tested with IMC-derived HIV and patient samples.
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PMID:Performance characteristics of the TRUGENE HIV-1 Genotyping Kit and the Opengene DNA Sequencing System. 1268 50

Hemoglobins (Hbs) are heme proteins encountered in all five kingdoms of living organisms. In plants, two different classes of Hbs have been identified: nonsymbiotic (class I) from both monocot and dicot species and symbiotic (class II) Hbs from nitrogen-fixing plants. This work reports the cloning and analysis of three nonsymbiotic Hb genes from wheat (Triticum aestivum) and potato (Solanum tuberosum). The Hb cDNAs were amplified by reverse transcriptase polymerase chain reaction (RT-PCR) using consensus oligonucleotide primers for nonsymbiotic Hbs.A wheat Hb cDNA (TaHb1) was isolated and shows a very high similarity to nonsymbiotic Hbs from Hordeum vulgare (98%) and Zea mays (83%). Another wheat Hb cDNA, designated TaHb2, exhibited strong similarity to truncated bacterial Hbs, the so-called 2-on-2 Hbs. In addition, a third Hb was cloned from potato, StHb. Expression analysis by RT-PCR demonstrated a very high expression level of the TaHb1 gene only in wheat roots. In contrast, the other wheat hemoglobin gene, TaHb2, was demonstrated to be constitutively expressed although differences in expression level in different tissues were observed. The expression of the TaHb1 gene is induced in wheat roots exposed to microaerobic conditions. The potato Hb gene, StHb, was highly expressed in roots and also in tubers and stem tissue although at much reduced levels.
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PMID:Molecular cloning and characterization of cDNAs encoding hemoglobin from wheat (Triticum aestivum) and potato (Solanum tuberosum). 1278 29

Pathological features and genomic basis of a rare case of ALK(+), CD30(-), CD20(-) large B-cell lymphoma were analyzed. A 36-year-old Japanese female was admitted because of lumbago and constitutional symptoms. Physical examination and laboratory tests showed anemia (hemoglobin, 7.5 g/dL), mild hepatosplenomegaly, and immunoglobin G (IgG) lambda-type monoclonal gammopathy (IgG, 2782 mg/dL). The lymphoma spread exclusively in extranodal sites such as bone marrow, liver, spleen, ovary, and muscle. Biopsy specimens obtained from the ovary showed monomorphic proliferation of large immunoblastic cells with basophilic cytoplasm, round-shaped nuclei with a high nuclear to cytoplasmic ratio, and prominent single nucleolus. Immunostaining with anti-anaplastic lymphoma kinase (ALK) antibody, ALK1, showed finely granular cytoplasmic staining pattern. These cells were also positive for epithelial membrane antigen, CD4, CD19, CD38, CD138, cytoplasmic IgG, and lambda chain, but negative for CD30 (Ber-H2), CD56, CD57, and other T- and B-cell markers. Southern blot analyses revealed that Ig heavy and lambda light chain genes, but not T-cell receptor (TCR) beta gene, were clonally rearranged. Chromosomal analyses by conventional G-banding, spectral karyotyping, and fluorescence in situ hybridization showed complex abnormality involving 2p23, and chromosome 2 was translocated to chromosome 17. As 2;17 translocation resulting in the fusion of clathrin heavy chain (CLTC) gene with ALK was previously reported in inflammatory myofibroblastic tumor, we performed reverse transcriptase-polymerase chain reaction and demonstrated that the lymphoma cells contained CLTC-ALK fusion transcript. Under the diagnosis of ALK(+), CD30(-), CD20(-) large B-cell lymphoma, she was treated with conventional combination chemotherapies. However, the lymphoma was primarily chemotherapy resistant, and the patient died 11 months after admission. We consider that this case confirms the existence of ALK(+), CD30(-), CD20(-) large B-cell lymphomas proposed by Delsol et al. (16) and further provides relevant information regarding their clinicopathological features and cytogenetics.
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PMID:ALK+, CD30-, CD20- large B-cell lymphoma containing anaplastic lymphoma kinase (ALK) fused to clathrin heavy chain gene (CLTC). 1292 Feb 29

The effect of the putative iron regulatory peptide hepcidin on iron absorption was investigated in mice. Hepcidin peptide was synthesized and injected into mice for up to 3 days, and in vivo iron absorption was measured with tied-off segments of duodenum. Liver hepcidin expression was measured by reverse transcriptase-polymerase chain reaction. Hepcidin significantly reduced mucosal iron uptake and transfer to the carcass at doses of at least 10 microg/mouse per day, the reduction in transfer to the carcass being proportional to the reduction in iron uptake. Synthetic hepcidin injections down-regulated endogenous liver hepcidin expression excluding the possibility that synthetic hepcidin was functioning by a secondary induction of endogenous hepcidin. The effect of hepcidin was significant at least 24 hours after injection of hepcidin. Liver iron stores and hemoglobin levels were unaffected by hepcidin injection. Similar effects of hepcidin on iron absorption were seen in iron-deficient and Hfe knockout mice. Hepcidin inhibited the uptake step of duodenal iron absorption but did not affect the proportion of iron transferred to the circulation. The effect was independent of iron status of mice and did not require Hfe gene product. The data support a key role for hepcidin in the regulation of intestinal iron uptake.
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PMID:Effect of hepcidin on intestinal iron absorption in mice. 1475 22

Campath-1H, a monoclonal antibody against human CD52, is used for the therapy of refractory or relapsed chronic lymphocytic leukemia (CLL). Treatment with campath is associated with an increased incidence of infections and also fatal reactivation of viral infections. Reactivation of hepatitis B virus (HBV) in HBsAg-positive patients is a well-documented complication of cytotoxic or immunosuppressive therapy and has also been observed after treatment with rituximab. To date, there are no reports on campath treatment in HBsAg carriers. Here, we present the case of a patient with heavily pretreated CLL who was HBsAg-positive with a high virus load (>2 billion copies/mL). He required treatment because of progressive CLL with massive bone marrow infiltration, severe anemia and thrombocytopenia. Campath was initiated and lamivudine, an inhibitor of reverse transcriptase, was simultaneously given to prevent HBV proliferation. During the treatment, no deterioration of liver parameters was observed, and the virus load decreased. After therapy with campath, hemoglobin and platelet counts increased markedly. This report shows that lamivudine is highly effective in inhibiting HBV proliferation and can be used to prevent HBV flare-up during campath treatment in patients tested positive for HBs antigen.
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PMID:Treatment of refractory chronic lymphocytic leukemia with Campath-1H in combination with lamivudine in chronic hepatitis B infection. 1496 66

Resistance to antiretroviral drugs in human immunodeficiency virus (HIV) disease may be discordant between blood and cerebrospinal fluid (CSF). However, there is no method by which patients who are likely to harbor resistant HIV in the CSF can be noninvasively identified. Activated monocytes are known to traffic through the brain and perivascular microglia are considered to "turnover" regularly from bone marrow-derived monocytes. Monocytes lack certain kinases necessary to metabolize some antiretroviral drugs, making it possible that monocytes, could deliver antiretroviral drugs to the brain. Low monocyte counts in the peripheral blood, however, would be expected to lead to decreased trafficking and turnover of monocytes, with less drug delivery to the brain. The authors hypothesized that this would increase the likelihood of drug resistant HIV in the central nervous system. To test this, 24 matching CSF and plasma samples that had been prospectively collected and stored from patients treated with nucleoside analogue reverse transcriptase inhibitor drugs were assessed for genotypic resistance. Those CSFs, with evidence of resistance mutations, were compared to those without for peripheral blood monocyte count, hemoglobin, CD4 cell count, and zidovudine (ZDV) use. The same analyses were repeated on the plasma samples. There were 11 CSFs with evidence of resistance mutations. The peripheral blood monocyte count was significantly lower in the CSF resistant group (0.29 +/- 0.16) versus (0.52 +/- 0.21) x 10(9)/L (P <.001). There was no difference between the groups according to hemoglobin, CD4 cell count, total white cell count, or use of ZDV. There was no difference between resistant and sensitive plasma samples according to peripheral blood monocyte count. To further test the hypothesis, the authors determined the concentrations of ZDV, stavudine, and abacavir in monocytes after each drug had been added to monocyte cultures. There was a significant decline in the concentration of each drug in the supernatant, implying that it had been "taken up" by the monocytes. These preliminary data suggest that peripheral blood monocytes may be important in delivery of antiretroviral drugs to the brain and the development of resistance.
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PMID:Can the peripheral blood monocyte count be used as a marker of CSF resistance to antiretroviral drugs? 1498 38

Oxidative stress plays an important role in the cardiovascular complications in end-stage renal disease (ESRD) patients on long-term hemodialysis (HD). Heme oxygenase-1 (HO-1) inhibits inflammatory events and protects against oxidative stress and endothelial injury. Therefore, we followed the effects of single HD sessions on HO-1 expression. A competitive reverse transcriptase PCR method was used to estimate HO-1 induction before and immediately after HD and 48 h later in 17 young uremic patients. We also measured the concentrations of plasma hemoglobin and bilirubin as indicators of hemolysis, the ferroxidase activity, and the erythrocyte-derived reduced and oxidized glutathione levels as oxidative stress markers, and the homocysteine levels as an independent risk factor. We found significant differences in HO-1 expression patterns in the patients, depending on the duration of HD treatment. Short-term HD [ n=7, median 19 months (9, 29 quartiles)] resulted in an elevated HO-1 expression, which was not further upregulated during HD. Long-term HD [ n=10, median 97 months (53, 150 quartiles)] led to downregulation of baseline HO-1 expression in ESRD patients. In these patients, a single HD session results in erythrocyte injury and a transient one- to five-fold elevation of HO-1 expression. The chronic downregulation of the baseline expression of HO-1 in long-term HD patients resulted in recurring oxidative stress during each HD session, which may contribute to accelerate the progression of atherosclerosis.
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PMID:Heme oxygenase 1 expression in young uremic patients on hemodialysis. 1498 81

Telomerase is a specialized type of reverse transcriptase that catalyzes the synthesis and extension of telomeric DNA. Activation of telomerase and stabilization of telomeres are considered necessary for immortalization of tumor cells. Chronic Myeloid Leukaemia (CML) is a good example to investigate the reactivation of telomerase as; after a variable period in chronic phase, CML undergoes further evolution. The aim of this work is to study telomerase activity in patients with philadelphia- positive CML and to compare the relative amount of telomerase activity between chronic phase, accelerated phase and blastic crisis. The study is conducted on 3 groups. Group I comprised ten newly diagnosed CML patients in chronic phase; five males and five females their ages ranged from 24-63 years (X = 44.1 +/- 11.2 years). Group II comprised ten patients in acute transformation (accelerated or blastic crisis phase); seven were males and three were females their ages ranged from 14 to 63 years ( X = 35.7 +/- 16.2 years). Ten healthy subjects comprised the control group III; five males and five females their ages ranged from 14-50 years ( X = 31.8 +/- 12.4 years). All patients were subjected to thorough history taking and clinical examination, complete blood picture with differential cell counts, bone marrow aspiration and/or biopsy, neutrophil alkaline phosphatase scoring by cytochemistry, immunophenotyping to identify the type of blast crisis, chromosomal analysis to detect Ph-positive cases, and measurement of telomerase activity by PCR-ELISA technique. Telomerase activity was highest in acute transformation with a range of (0.252-1.896) and mean of 1.521 0.496, while in chronic phase ranged between 0.67 and 0.743 with a mean of 0.305 +/- 0.109 and in normal controls the range was 0.45 to 0.195 with a mean of 0.102 +/- 0.048. The difference between groups was statistically significant. No correlation was found between the activity of the telomerase and hemoglobin, platelet, leucocyte counts, percentage of peripheral blood, bone marrow blasts, basophils, bone marrow cellularity, the type of crisis as well as leucocyte alkaline phosphatase scoring. In conclusion; The increased level of telomerase activity as noticed in the different stages of CML indicates its association with disease progression and can be used as a useful marker for evaluating development of the course.
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PMID:Telomerase activity in Philadelphia positive chronic myeloid leukaemia. 1572 80

The detection of prostate-specific antigen (PSA) mRNA by reverse transcriptase-polymerase chain reaction (RT-PCR) in the bloodstream of prostate cancer patients has been hypothesized as a prognostic marker, however little data are available concerning the association between this molecular marker and other laboratory values of potential importance. In this study, in patients with hormone-refractory prostate cancer (HRPC), relationships were determined between PSA RT-PCR positivity, survival, and various relevant markers including serum PSA, LDH, albumin, alkaline phosphatase and hemoglobin. A total of 19/30 HRPC patients were positive for PSA by RT-PCR. Positivity was significantly linked to serum PSA (P=0.004) and serum alkaline phosphatase (P=0.026) but not to the other laboratory variables. Median survival time for RT-PCR-positive patients was 9 months, compared to 19 months for RT-PCR-negative patients (P=0.035). Median survival time for patients with a hemoglobin>or=11 g/dL was 12 months, compared to 9 months for patients with <11 g/dL (P=0.005). Dichotomized (>or=or<median) serum PSA, LDH, alkaline phosphatase, and albumin were not significantly associated with survival in univariate analyses. In multivariate analysis, only dichotomized hemoglobin (<11 g/dL vs. >or=11 g/dL) remained statistically significant (P=0.019), indicating that RT-PCR had no independent association with survival after controlling for hemoglobin status in this study.
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PMID:Relationships between reverse transcriptase-polymerase chain reaction for prostate specific antigen, survival, and various prognostic laboratory factors in patients with hormone refractory prostate cancer. 1590 15

Hemin, a critical component of hemoglobin, is an active ingredient of a biologic therapeutic approved by the Food and Drug Administration for the treatment of acute porphyries. This report describes a biological function of this molecule in inducing host defense against HIV-1 infection via heme oxygenase-1 (HO-1) induction. Treatment of monocytes with hemin substantially inhibited HIV replication, as evident by nearly undetectable viral RNA and cell-free HIV-1 p24 protein in a dose-dependent manner. Hemin exposure of these cells before infection, at the time of infection, or after infection caused >90% reduction of HIV DNA with substantially low levels of HIV-1 p24 and HIV-associated cytopathic effects. In addition, hemin treatment significantly suppressed infection of both monocytes and T cells inoculated with R5, X4, R5X4 tropic strains, and reverse transcriptase-resistant, azidothymidine-resistant, ddC/ddI-resistant, nivirapine-resistant, and other clinical HIV isolates. Intraperitoneal administration of hemin 4 days after HIV infection reduced viral load in the serum of human PBMC-reconstituted nonobese diabetic SCID mice by >6-fold. Suppression of HIV replication in hemin-activated cells correlated with the induction of HO-1 and was attenuated by tin protoporphyrin (SnPP) IX, an inhibitor of HO-1 activity, suggesting a pivotal role of this endogenous enzyme in the regulation of HIV infection. Hemin-induced HO-1 induction in the CCR-5, CXCR-4, and CD4 coexpressing GHOST(3) cells was consistent with the inhibition of Tat-dependent activation of long terminal repeat promoter leading to reduced GFP expression. These findings suggest an important role of hemin-induced HO-1 activity as a host defense mechanism against HIV-1 infection.
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PMID:Hemin activation ameliorates HIV-1 infection via heme oxygenase-1 induction. 1654 62


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