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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A procedure for producing and purifying recombinant HIV-1 and HIV-2 reverse transcriptase (RT) is described. These enzymes are produced by Escherichia coli-transformed with a plasmid containing the gene encoding for either the human immunodeficiency virus type 1 (HIV-1) or HIV-2 RT protein. Both proteins are partially processed by host cell proteases giving rise to a mixture of heterodimeric and nonheterodimeric products, which are subsequently resolved to near homogeneity by chromatography on phosphocellulose, Q-Sepharose, and hydrophobic interaction HPLC. Both HIV-1 (66/51 kDa) and HIV-2 (68/54 kDa) heterodimeric enzymes devoid of excess unprocessed (p66 or p68) precursors are isolated, enabling comparative enzymatic characterization of the fully active (and biologically relevant) heterodimeric forms. Homogenous HIV-1 and HIV-2 RT purified by this methodology exhibit near equivalent polymerase and RNase H activities.
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PMID:Comparative purification of recombinant HIV-1 and HIV-2 reverse transcriptase: preparation of heterodimeric enzyme devoid of unprocessed gene product. 128 95

In a series of 33 cynomolgus monkeys (Macaca fascicularis) experimentally infected with Simian Immunodeficiency virus (SIV), strain smm3, 13 animals developed malignant Non-Hodgkin lymphomas. These lymphomas presented with unusual primary manifestations like in the orbita, testes, and brain. The morphological features and immunophenotyping identified the tumors as high malignant B-cell lymphomas. In all tumors as well as in tumor-derived cell lines a cynomolgus B-lymphotropic herpes virus (CBLV) with structural homogeneity to the Epstein-Barr virus (EBV) could be demonstrated by Southern blotting with EBV-specific probes. The lymphoma cells also expressed CBLV-associated nuclear antigens involved in B-cell transformation crossreacting with EBNA-specific human sera and monoclonal antibodies. Ig-gene rearrangement studies revealed clonal populations, however, no translocations of the c-myc oncogene could be detected. The lymphomas developing with high frequency in SIV-induced immunodeficiency resemble a major subtype of human EBV-associated AIDS lymphomas. This animal model can therefore be used to further elucidate interactions of HIV and EBV in AIDS-related lymphomagenesis.
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PMID:[Opportunistic malignant lymphomas in SIV infected primates--a model for Epstein-Barr virus associated lymphomas in AIDS]. 128 56

Ten monoclonal antibodies prepared against a soluble, recombinant form of gp160, derived from the IIIB isolate of HIV-1, were characterized. Four of the antibodies neutralized HIV-1IIIB infectivity in vitro, three blocked the binding of recombinant gp120 to CD4, three were reactive with gp41, and one preferentially reacted with an epitope on gp120 within the gp160 precursor. All three CD4 blocking antibodies bound to distinct epitopes, with one mapping to the C1 domain, one mapping to the C4 domain, and one reactive with a conformation-dependent, discontinuous epitope. Of these, the antibody reactive with the discontinuous epitope exhibited neutralizing activity against homologous and heterologous strains of HIV-1. The binding of these monoclonal antibodies to a panel of seven recombinant gp120s prepared from diverse isolates of HIV-1 was measured, and monoclonal antibodies with broad cross reactivity were identified. The epitopes recognized by 7 of the 10 monoclonal antibodies studied were localized by their reactivity with synthetic peptides and with fragments of gp120 expressed as fusion proteins in a lambda gt-11 gp160 epitope library.
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PMID:Monoclonal antibodies to the extracellular domain of HIV-1IIIB gp160 that neutralize infectivity, block binding to CD4, and react with diverse isolates. 128 8

An aqueous extract of Phyllanthus niruri (Euphorbiaceae) inhibited human immunodeficiency virus type-1 reverse transcriptase (HIV-1-RT). The inhibitor against HIV-1-RT in this plant was purified by combination of three column chromatographies, Sephadex LH-20, cellulose, and reverse-phase high-performance liquid chromatography. The inhibitor was then identified by nuclear magnetic resonance (NMR) spectra as repandusinic acid A monosodium salt (RA) which was originally isolated from Mallotus repandus. The 50% inhibitory doses (ID50) of RA on HIV-1-RT and DNA polymerase alpha (from HeLa cells) were 0.05 microM and 0.6 microM, respectively, representing approximately a 10-fold more sensitivity of HIV-1-RT compared with DNA polymerase alpha. RA was shown to be a competitive inhibitor with respect to the template-primer while it was a noncompetitive inhibitor with respect to the substrate. RA as low as 10.1 microM inhibited HIV-1-induced cytopathogenicity in MT-4 cells. In addition, 4.5 microM of RA inhibited HIV-1-induced giant cell formation of SUP-T1 approximately 50%. RA (2.5 microM) inhibited up to 90% of HIV-1 specific p24 antigen production in a Clone H9 cell system.
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PMID:HIV-1 reverse transcriptase inhibitor from Phyllanthus niruri. 128 10

Current treatment options for acquired-immunodeficiency syndrome (AIDS)-related non-Hodgkin's lymphoma (NHL) are unsatisfactory because of excessive toxicity rates and frequent recurrence of lymphoma. In this phase II study, we evaluated a novel 12 week chemotherapy program with respect to feasibility, toxicity and therapeutic results. Thirty HIV-seropositive patients with intermediate grade or small non-cleaved cell NHL received a 12 week program of weekly intravenous and oral chemotherapy consisting of etoposide, adriamycin, cyclophosphamide, bleomycin, vincristine, methotrexate and prednisone as well as biweekly intrathecal cytosine arabinoside. Prophylaxis against Pneumocystis carinii pneumonia (PCP) and candida were given routinely. The overall objective response rate was 73% with 33% complete responders. The time to progression for those stable or responding was 9.4 months. Five of 10 complete responders are well and free of disease 13.2 to 24.5 months from diagnosis. Median survival for the 30 patients was 8.1 months. NHL was the most common cause of death (13/22); opportunistic infection caused only one death (cryptococcal meningitis). Only 1 case of PCP occurred. The major toxicity was neutropenia. In conclusion this regimen resulted in response rates similar to other reports with acceptable toxicity and a very low incidence of PCP. Relapse of NHL remains a major challenge, however, and further studies are needed. Routine PCP prophylaxis should be incorporated into new trials of therapy for AIDS-related NHL.
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PMID:Treatment of AIDS-related non-Hodgkin's lymphoma with a twelve week chemotherapy program. 128 56

We investigated the pharmacokinetics of antipyrine and the endogenous plasma levels of interferon alpha (IFN alpha), interferon beta (IFN beta) and interferon gamma (IFN gamma) in 10 otherwise healthy volunteers before outbreak (baseline) and in the symptomatic interval of an acute viral respiratory infection, and also in HIV-1 infected homosexual patients in stadium WR 2-3 (n = 11) and WR 5-6 (n = 11) before and one day after application of the antiretroviral agent zidovudine 800 mg day-1 for 14 days. Interferons were measured by RIA or ELISA, respectively. The concentrations of antipyrine and its metabolites in serum and urine were measured by HPLC. Antipyrine is a pharmacokinetic model substance to estimate the cytochrome P 450 enzyme activity. The plasma levels of IFN alpha and IFN gamma in the symptomatic interval of an acute viral respiratory infection were elevated from 4.7 U ml-1 to 12.6 U ml-1 and from 0.3 U ml-1 to 3.4 U ml-1, respectively. The antipyrine clearance showed a significant decrease from 57.9 ml min-1 to 45.0 ml min-1. In the HIV-1 infected patients in stadium WR 2-3 no alterations in plasma levels of interferons or in the pharmacokinetics of antipyrine were observed after treatment with zidovudine. In contrast to these results, in patients in stadium WR 5-6 we found a significant decrease of IFN alpha and an elevation of the clearance and the clearances to metabolite of antipyrine by about 20 percent.
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PMID:Endogenous interferon plasma levels and antipyrine pharmacokinetics in patients with viral infections. 128 84

29 Rifamycins were tested for inhibition of Reverse Transcriptase (RT) as potential anti HIV drugs. Two purified commercial enzymes from M-MuLV and RAV-2 were used. Anti-RT activity was also measured on a crude lysate of HIV-1. The results show that some derivatives have interesting levels of activity on isolated M-MuLV and RAV-2 RTs, while they are less active on the RT in the crude HIV-1 lysate. The active derivatives include oximes and hydrazones, alkylaminoderivatives, open ansa-chain derivatives and derivatives carrying a modified nucleoside.
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PMID:Rifamycins as inhibitors of retroviral reverse transcriptase from M-MuLV, RAV-2, and HIV-1. 128 14

A fully automated instrument for multiple simultaneous peptide synthesis was constructed to provide large numbers of peptides for immunological research. The synthesis is performed in a flow-through mode with the conventional solid supports contained in 48 individual reaction columns. The instrument is based on a commercial autosampler equipped with a motor-driven syringe for accurate delivery of reagents and a robot arm carrying a dispenser needle. Dedicated software was developed to compile overlapping peptides from a given protein sequence and to control all functions of the robot. In situ activation by BOP was chosen as the optimized chemistry protocol. The peptides are cleaved from the resin in the reactors used for synthesis, thus minimizing handling. Performance of the instrument was demonstrated by synthesis of overlapping 14-mer peptides derived from the sequence of HIV reversed transcriptase. A second mode of operation allows the synthesis to be carried out on the surface of polyethylene pins. Peptides derived from the sequence of human TNF were synthesized using this method and used to characterize antibodies raised against the intact protein.
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PMID:Automated multiple peptide synthesis. 128 42

L-696,229 is a potent and specific inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase and is currently undergoing clinical evaluation. In vivo metabolism in rats was investigated using an intravenous bolus dose of 5 mg/kg [3H]L-696,229. The amount of radioactivity eliminated in bile and urine over a period of 6 hr was 60 and 22%, respectively. Radiochromatographic analysis of the bile and urine showed that L-696,229 was metabolized rapidly and completely to several common metabolites. Sequential oxidation at the alpha-position of the 5-ethyl group to an acetyl moiety, aromatic hydroxylation of the benzoxazole group (position C4', C6', or C7'), and subsequent sulfate conjugation were the major metabolic pathways as determined by the application of enzymatic hydrolysis, FAB-MS, and 1H- and 13C-NMR spectroscopies. The in vitro metabolism of this 2-pyridinone derivative with rat liver slices resulted primarily in hydroxylation at the 6-methyl and 5-ethyl groups. The 6-hydroxymethyl- and 5-alpha-hydroxyethyl analogs were also inhibitors of HIV-1 reverse transcriptase.
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PMID:Metabolism of a new HIV-1 reverse transcriptase inhibitor, 3-[2-(benzoxazol-2-yl)ethyl]-5-ethyl-6-methylpyridin-2(1H)-one (L-696,229), in rat and liver slices. 128 69

Hematopoietic growth factors may mitigate the cytopenias that frequently complicate HIV disease or its treatment. Clinical and in vitro studies have indicated the ability of granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF) or erythropoietin (EPO) to overcome the myelosuppression of HIV or many of the drug therapies used in the care of HIV-infected individuals. In addition, neutrophil or monocyte functional abnormalities observed in AIDS patients may be improved by the use of GM-CSF. Issues which may distinguish the use of hematopoietic growth factors in AIDS as compared with in other clinical settings include: 1) interaction of the growth factor with other cytokines which are aberrantly expressed, 2) direct effects of the growth factor on the replicative activity of HIV, and 3) potential interactions of the growth factor with other concurrently administered medications. This review focuses on the potential roles and limitations of growth factor use in AIDS and reviews the clinical studies using GM-CSF in HIV-infected individuals.
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PMID:The use of GM-CSF in AIDS. 128 4


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