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)

Immunosuppression suspected to be associated with retrovirus infection was diagnosed in an 18-month-old female llama. The llama had a 6-month history of weight loss, intermittent lameness, and infections that were nonresponsive to treatment. Serial CBC indicated persistent nonregenerative anemia and leukopenia characterized by absolute neutropenia and lymphopenia. Functional hypoplasia of myeloid and erythroid cell lines was detected in serial bone marrow biopsy specimens. Notable pathologic findings included inadequate hematopoiesis, generalized lymphoid hypoplasia and plasma cell depletion, and pulmonary alveolar histiocytosis. Pneumocystis carinii cysts and viral particles of the size and morphologic features consistent with the retrovirus family were observed in lung sections examined by transmission electron microscopy. Antemortem macrophage and postmortem lymph node cultures were positive for reverse transcriptase activity.
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PMID:Apparent retrovirus-induced immunosuppression in a yearling llama. 133 Oct

We studied the immediate and long-term effects of azidothymidine (AZT) and heme on murine hemopoietic and stromal progenitor cells in vivo and in vitro. Treatment of mice for 37 days with AZT produced anemia and leukopenia, whereas combined treatment with heme abrogated some of the toxic effects which were apparent even 2 weeks after cessation of treatment. Quantitation of spleen (CFU-S), erythroid (BFU-E) and myeloid (CFU-GM) colony formation from AZT-exposed animals revealed reductions in these progenitors, and this was partially reversed after heme treatment, especially when mice were allowed a 2-week recovery period. Long-term bone marrow cultures (LTBMC) of cells from treated groups revealed difficulty in establishing an adherent cell layer (ACL) by the first week in culture. Total cellularity, CFU-S, BFU-E and CFU-GM clonogenic potential of cultures remained depressed throughout 10 weeks of culture, whereas heme treatment overcame these depressions when AZT-exposed mice were allowed to recover for 14 days prior to culture of their cells in LTBMC. Interleukin-1 (IL-1) treatment to the same recovery group of AZT-exposed mice also resulted in an improvement of CFU-GM growth in LTBMC that was not seen in the nonrecovered group. Transplantation of cells from treated mice under the renal capsule of recipient mice revealed that AZT depressed the regeneration of osteogenic and hemopoietic cell growth within ectopic foci. These effects were reversed with heme treatment in vivo. In other experiments, heme was found to inhibit human immunodeficiency virus (HIV-1) reverse transcriptase and to potentiate the activity of AZT triphosphate against HIV-1 reverse transcriptase. In summary, these results demonstrate that AZT inhibits the growth and development of a variety of hemopoietic, stromal and adherent cells in vivo and in vitro. Treatment of animals with heme produced recovery to near normal levels and suggests possible therapeutic potential.
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PMID:Long-term bone marrow stromal and hemopoietic toxicity to AZT: protective role of heme and IL-1. 767 12

We conducted a feasibility study of continuous etoposide infusion, which was expected to suppress DNA repair after radiation, combined with radiation in patients with advanced non-small cell lung cancer (NSCLC). Between July 1995 and January 1997, 10 patients with NSCLC were registered. Thirty-six mg/m2/day etoposide was infused continuously for a mean of 19 days (range 14-26). Patients tolerated a mean total dose of accelerated hyperfractionated thoracic radiotherapy (1.5 Gy twice per day) of 52.6 Gy (range 33-60). The primary tumors of 7 patients showed partial responses and distant metastasis progression occurred before primary tumor progression in all 7 responders. The hematological adverse effects of chemoradiotherapy were grade 3 or 4 leukopenia in all 10 patients, grade 3 anemia developed in 3, and 2 had grade 3 thrombocytopenia. Six patients contracted infections and one of them died of pneumonia. The major non-hematological adverse effect was esophagitis, which was grade 3 in 3 patients, one of whom died of renal dysfunction. The serum etoposide concentrations were 1.6-2.0 microgram/ml, except in one patient, who had liver dysfunction due to B-type hepatitis. DNA repair gene XRCC1 mRNA expression in peripheral blood mononuclear cells was analyzed, using the reverse transcriptase-polymerase chain reaction, in 8 patients and was suppressed during etoposide infusion in 2. No relationship was observed between serum etoposide concentration and XRCC1 expression and clinical outcome. In conclusion, continuous etoposide infusion combined with thoracic radiation induces severe toxicity and should be given only after careful consideration.
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PMID:A feasibility study of continuous etoposide infusion combined with thoracic radiation for non-small cell lung cancer. 1002 87

The aim of this novel diagnostic approach is to monitor cytomegalovirus (CMV) infection in immunocompromised transplant recipients using early, sensitive, and specific predictors before and during antiviral therapy. The peripheral blood cells of 20 patients after transplantation (9 liver, 7 kidney, 4 simultaneous kidney-pancreas) were studied for an early diagnosis of acute infection. The mRNA and DNA of human CMV immediate-early antigen (IEA) were detected by nested-polymerase chain reaction (PCR) assay. Results of nested PCR were compared with the immunological detection of antigen pp65 and serological diagnosis of CMV infection. All data were correlated with clinical symptoms like leukopenia, thrombopenia, pneumonia, and allograft-rejection reaction. Of 20 transplant recipients, 12 were infected by CMV, and 9 suffered from a CMV-related disease. CMV mRNA were detected simultaneously with antigen pp65 and CMV DNA in all patients with symptomatic infection. Additionally, CMV mRNA was found over a longer period after ganciclovir treatment of infected recipients. Nested reverse transcriptase (RT)-PCR for CMV-IEA mRNA allows a sensitive and specific diagnosis of an acute CMV infection. CMV mRNA was found to be a good marker of acute viremia and could be a useful tool for CMV monitoring over the whole period of disease management, even during antiviral therapy.
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PMID:Diagnosis and monitoring of acute cytomegalovirus infection in peripheral blood of transplant recipients by nested reverse transcriptase polymerase chain reaction (RT-PCR). 1111 34

Clinical manifestations of primary human immunodeficiency virus (HIV) infection (acute retroviral syndrome) and virologic characteristics of HIV-1 have rarely been described in Taiwan. Medical records of patients followed at the National Taiwan University Hospital between June 1994 and September 2003 were retrospectively reviewed to identify HIV-infected patients who were diagnosed with primary HIV infection. Blood specimens obtained at the diagnosis of primary HIV infection were submitted for viral subtyping and genotypic resistance assay. Twenty out of 940 patients were diagnosed with acute retroviral syndrome during the study period. All of the patients were males, with a median age of 31 years (range, 23 to 42 years); all were men who had sex with men. The most common clinical manifestations were fever (95%), generalized lymphadenopathy (75%), pharyngitis (70%), skin rashes (70%), and gastrointestinal symptoms (60%) including nausea, vomiting, and diarrhea. Thrombocytopenia (35%), leukopenia (35%), and elevated liver function test (50%) were seen in the laboratory tests. The median CD4 lymphocyte count was 312 cells/microL (range, 112-520 cells/microL), and the plasma HIV RNA load by reverse transcriptase-polymerase chain reaction was 230,500 copies/mL (range, 602 --> 750,000 copies/mL). No major resistance mutations on protease or reverse transcriptase were identified in the 11 available viral isolates. We conclude that primary HIV infection was rarely diagnosed in the designated hospital for HIV care in Taiwan. More education of health care providers and counseling of persons at risk to increase awareness of HIV infection are urgently needed in Taiwan in order to facilitate earlier diagnosis of primary HIV infection and prevent further transmission.
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PMID:Clinical presentations and virologic characteristics of primary human immunodeficiency virus type-1 infection in a university hospital in Taiwan. 1549 7

Nevirapine is a non-nucleoside reverse transcriptase inhibitor used in the treatment of human immunodeficiency virus (HIV)-infected patients and in post-exposure prophylaxis. However, its use has recently been limited because of adverse cutaneous and hepatic effects. We report an HIV-infected woman who developed mild leukopenia as the first sign of a nevirapine-related adverse event, which was followed by skin and hepatic toxicity associated with a more severe leukopenia.
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PMID:Severe leukopenia associated with mild hepatotoxicity in an HIV carrier treated with nevirapine. 1550 79

Although both leukopenia and thrombocytopenia are not uncommon hematological findings among patients with novel 2009 H1N1 influenza virus infection, immune thrombocytopenic purpura has rarely been shown to be associated with this novel influenza A infection. Here, we describe a previously healthy adolescent who presented with fever, influenza-like symptoms and acute onset of generalized petechiae and active oral mucosa bleeding on the third day of his illness. Severe leukopenia and thrombocytopenia were found. There was neither malignancy nor blast cells found by bone marrow aspiration. Real-time reverse transcriptase polymerase chain reaction was positive for novel 2009 H1N1 influenza infection. Novel influenza-associated atypical immune thrombocytopenic purpura was diagnosed. The patient recovered uneventfully after oseltamivir and methylprednisolone therapy.
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PMID:Acute immune thrombocytopenic purpura in an adolescent with 2009 novel H1N1 influenza A virus infection. 2196 53

Current guidelines on first-line treatment of HIV infection recommend a combination of at least three antiretroviral drugs from two different pharmacological classes: at least two nucleoside or nucleotide reverse transcriptase inhibitors plus either a protease inhibitor or a non-nucleoside reverse transcriptase inhibitor. Among the available nucleoside or nucleotide inhibitors, some guidelines recommend the tenofovir + emtricitabine combination for adults. The abacavir + lamivudine and zidovudine + lamivudine combinations have similar efficacy but are only considered alternative options. What is known of the differences in adverse effects between zidovudine, tenofovir and abacavir? How should their respective adverse effect profiles influence the choice between available combinations? We sought answers to these questions by reviewing the literature using the standard Prescrire methodology. Treatment withdrawals for adverse effects or fear of lipoatrophy are less frequent with tenofovir than with zidovudine. Similarly, treatment withdrawals because of adverse effects are less frequent with abacavir+ lamivudine than with tenofovir + emtricitabine. Zidovudine mainly has haematological adverse effects (anaemia, leukopenia) and also causes lipoatrophy. Tenofovir mainly causes renal disorders (tubulopathy, Fanconi syn- drome), bone disorders (osteoporosis, fractures, osteomalacia) and gastrointestinal disorders. Abacavircan cause life-threatening hypersensitivity reactions, even (al- beit less frequently) in patients who do not carry the HLA-B*5701 allele. It probably also has cardiovascular adverse effects, including myocardial infarction. In practice, the choice between the tenofovir + emtricitabine, abacavir + lamivudine or zidovudine + lamivudine combinations should be made on a case-by-case basis, taking into account the patient's renal function, hepatitis B virus serostatus, and other ongoing treatments, as well as poten- tial adverse effects, treatment moni- toring, and convenience.
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PMID:Zidovudine, tenofovir or abacavir? Different adverse effect profiles. 3073 Jun 51

The frequency of travel-related infections in the world has increased due to the easily and widespread use of travel facilities in the 21st century. Vector-borne diseases are an important part of infectious diseases. Dengue fever is one of the travel-related infections that has been reported increasingly in recent years through the development of diagnostic methods. The aim of this report was to present two Dengue fever cases originating from travel. There was a story of mosquito bite during a trip to Sri Lanka travel in our first case. The patient was 30 years old and maculopapular rash appeared on the fifth day of contact. Three days after the onset of the rash, she has admitted to our clinic, complaining with fever and chills. Increased leukopenia and muscle enzymes were detected in the laboratory analysis. Real-time reverse transcriptase polimerase chain reaction (RT-PCR) was positive in the serum sample. The patient was followed up with supportive care and discharged by improvement. The second case, a 24-year-old male, had a story of mosquito bite during his trip to Malaysia. After the patient complained of fever, chills, fever, nausea, vomiting and muscle pain, the Dengue virus (DENV) NS1 antigen test performed in this country was found to be positive. In the second case, there was no maculopapular rash and laboratory analysis showed an increase in leukopenia, thrombocytopenia and muscle enzymes. RT-PCR positivity was detected in the serum sample. The patient was followed up with supportive treatment and discharged with cure. DENV infections are caused by DENV which is common in the tropical areas of the world. There are four DENV-1, DENV-2, DENV-3 and DENV-4 serotypes. DENV infections can present different clinical manifestations such as asymptomatic disease, viral syndrome, Dengue haemorrhagic fever, and Dengue shock syndrome. Dengue fever is often accompanied by arthritis, maculopapular rash and high fever. Our cases were defined as Dengue fever according to this definition. In the diagnosis of the disease, it is necessary first to be suspicious of the disease and the travel history must be questioned. In the definitive diagnosis, virus isolation, antigen, nucleic acid detection and serological tests are used. The virus can be isolated from blood, serum, urine and tissues. In the first five days after beginning of the symptoms associated with DENV infections, serum RT-PCR and Dengue NS1 antigen test may be positive.
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PMID:[Travel Related Fever and Rash: Two Cases of Dengue Fever]. 3141 37

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