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

A method for the determination of a non-nucleoside HIV-1 reverse transcriptase inhibitor in human plasma is described. Plasma samples are extracted using phenyl solid-phase extraction columns. The extract is analyzed by high-performance liquid chromatography with a polybutadiene-coated alumina column and a mobile phase of methanol-0.025 M pH 8 dibasic sodium phosphate buffer (1:1, v/v). Detection is based on ultraviolet absorbance at 326 nm. The assay was validated in the concentration range 10-500 ng/ml when 1-ml aliquots of plasma are extracted. The assay has been utilized to support human pharmacokinetic studies.
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PMID:High-performance liquid chromatographic procedure for the determination of a non-nucleoside HIV-1 reverse transcriptase inhibitor in human plasma. 138 49

A general method for large scale preparation of uniformly isotopically labeled ribonucleotides and RNAs is described. Bacteria are grown on isotopic growth medium, and their nucleic acids are harvested and degraded to mononucleotides. These are enzymatically converted into ribonucleoside triphosphates, which are used in transcription reactions in vitro to prepare RNAs for NMR studies. For 15N-labeling, E.coli is grown on 15N-ammonium sulfate, whereas for 13C-labeling, Methylophilus methylotrophus is grown on 13C-methanol, which is more economical than 13C-glucose. To demonstrate the feasibility and utility of this method, uniformly 13C-labeled ribonucleotides were used to synthesize a 31 nucleotide HIV TAR RNA that was analyzed by 3D-NMR. This method should find widespread use in the structural analysis of RNA by NMR.
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PMID:Preparation of isotopically labeled ribonucleotides for multidimensional NMR spectroscopy of RNA. 138 28

Mice containing the HIV-1 long terminal repeat (LTR) regulating the expression of firefly luciferase reporter gene were investigated for their use as a model for activation of the LTR. As a limited test of this model, a number of different factors were screened for their ability to affect reporter gene activities in the skin. Reporter gene levels were increased in the skin by topical treatment of dimethylsulfoxide, retinoic acid, phorbol ester, ultraviolet light, and hydrogen peroxide, all of which have previously been shown to cause increased HIV production in cultured human cells. Topically applied arachidonic acid, histamine, ethanol, acetone, and methanol did not increase reporter gene activities. A lack of published reports on activation of HIV-1 in human cells by these agents suggests that they do not activate viral expression in human cells, which corroborates with the findings of this report. Minor forms of skin wounding and intraperitoneally administered psoralen plus ultraviolet light also increased reporter gene activities in skin. Control and test treatments could be performed on the same mouse and repetitive samples could be obtained from each treatment area. These transgenic mice might be useful as predictive models for regulation of the LTR in epidermal or dendritic cells.
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PMID:HIV-1 LTR activation model: evaluation of various agents in skin of transgenic mice. 145 30

A series of nucleosides were synthesized in which the 4'-hydrogen was substituted with either an azido or a methoxy group. The key steps in the syntheses of the 4'-azido analogues were the stereo- and regioselective addition of iodine azide to a 4'-unsaturated nucleoside precursor followed by an oxidatively assisted displacement of the 5'-iodo group. The 4'-methoxynucleosides were made via epoxidation of 4'-unsaturated nucleosides with in suit epoxide opening by methanol. Reaction-mechanism considerations, empirical conformation rules, NMR-based conformational calculations, and NOE experiments suggest that the 4'-azidonucleosides prefer a 3'-endo (N-type) conformation of the furanose moiety. When evaluated for their inhibitory effect on HIV in A3.01 cell culture, all the 4'-azido-2'-deoxy-beta-D-nucleosides exhibited potent activity. IC50's ranged from 0.80 microM for 4'-azido-2'-deoxyuridine (6c) to 0.003 microM for 4'-azido-2'-deoxyguanosine (6e). Cytotoxicity was detected at 50-1500 times the IC50's in this series. The 4'-methoxy-2'-deoxy-beta-D-nucleosides were 2-3 orders of magnitude less active and less toxic than their azido counterparts. Modifications at the 2'- or 3'-position of the 4'-substituted-2'-deoxynucleosides tended to diminish activity. Further evaluation of 4'-azidothymidine (6a) in H9, PBL, and MT-2 cells infected with HIV demonstrated a similar inhibitory profile to that of AZT. However, 4'-azidothymidine (6a) retained its activity against HIV mutants which were resistant to AZT.
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PMID:Synthesis and anti-HIV activity of 4'-azido- and 4'-methoxynucleosides. 157 38

Crude extracts of dried leaves of Hyssop officinalis showed strong anti-HIV activity as measured by inhibition of syncytia formation, HIV reverse transcriptase (RT), and p17 and p24 antigen expression, but were non-toxic to the uninfected Molt-3 cells. Ether extracts from direct extraction (Procedure I), after removal of tannins (Procedure II), or from the residue after dialysis of the crude extract (Procedure III), showed good antiviral activity. Methanol extracts, subsequent to ether, chloroform and chloroform ethanol extractions, derived from procedure I or II, but not III, also showed very strong anti-HIV activity. In addition, the residual material after methanol extractions still showed strong activity. Caffeic acid was identified in the ether extract of procedure I by HPLC and UV spectroscopy. Commercial caffeic acid showed good antiviral activity in the RT assay and high to moderate activity in the syncytia assay and the p17 and p24 antigen expression. Tannic acid and gallic acid, common to other teas, could not be identified in our extracts. When commercial products of these two acids were tested in our assay systems, they showed high to moderate activity against HIV-1. Hyssop officinalis extracts contain caffeic acid, unidentified tannins, and possibly a third class of unidentified higher molecular weight compounds that exhibit strong anti-HIV activity, and may be useful in the treatment of patients with AIDS.
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PMID:Inhibition of HIV replication by Hyssop officinalis extracts. 170 26

Cryostat-sections of biopsies from HIV-infected patients or HIV/SIV-infected experimental animals pose a biohazard risk to laboratory workers. The objective of this study was to select a procedure that appropriately fixes cryo-sections and reduces the risk of HIV-1 infectivity. This inactivation procedure should preserve antigen binding capacity of host-produced antibodies and the antigenic structure of epitopes present in these tissues, while retaining sufficient morphologic detail. We tested the effect of seven different established fixation-inactivation procedures for HIV-1 on the detection of specific antibodies and membrane markers, compared to acetone fixation as a reference. Frozen sections of spleens from mice immunized with trinitrophenyl (TNP)-Ficoll were incubated with TNP-alkaline phosphatase to detect specific antibody-forming cells and follicular immune complexes containing TNP-specific antibodies. In addition, sections were stained with monoclonal antibodies directed against IgM (187-1), T-cells (anti Thy-1), and marginal metallophilic macrophages (MOMA-1). Five procedures proved useful as they gave results similar to regular acetone fixation. In contrast, two procedures with a methanol-containing fixative obscured both antigen binding sites and membrane antigens. Subsequently, these five selected procedures were tested on glass slide preparations of HIV-1 infected cell lines, expressing HIV-1 determinants defined by monoclonal antibodies. Finally, the procedures were tested on sections of an HIV-1 infected human lymph node, for detection of HIV-specific B-cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Fixation of cryo-sections under HIV-1 inactivating conditions: integrity of antigen binding sites and cell surface antigens. 191 74

The brands of condom which are marketed in Denmark were examined for nonoxynol content with the object of assessing whether such content is sufficient to prevent HIV spread and in relation to defects in its potential effectiveness. Using the methods of methanol/water extraction and subsequent high performance liquid chromatography (with the standard nonoxynol content being 40 mg [100%] per condom), 1 brand of condom contained 65%, 2 contained 50-55%, and 4 between 25-33%. The nonoxynol content was found to be evenly distributed between the outer and inner surfaces of the condom. With a theoretical distribution volume of 6 ml (tearing during vaginal coitus), it was found that 3 brands of condom did not achieve the HIV-inhibiting nonoxynol concentration of 0.05%. This was ascertained by measuring the quantity of nonoxynol on the distal 5 cm of the condoms. During anal sex, the distribution volume is greater which results in lower nonoxynol concentrations and thus increased risk for HIV infection. It is concluded that nonoxynol content in the condoms marketed in Denmark should be increased in order to inactivate HIV in the event of condom failure. (author's modified)
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PMID:[The nonoxynol content in condoms is insufficient to inhibit the human immunodeficiency virus (HIV)]. 217 90

A method has been developed to measure the concentration of total phosphorylated zidovudine (ZDV) inside peripheral blood leucocytes (PBLs) using a modified commercial radioimmunoassay (RIA) specific for ZDV. ZDV 5'-monophosphate was readily synthesized and used as a procedural control for RIA modification. PBLs were isolated from healthy volunteers and incubated with ZDV for 24 h to allow metabolic phosphorylation. Viable cells were counted, washed, and extracted overnight with 60% methanol. After evaporation, the extract was reconstituted in Tris buffer, pH 9.5. Because of minimal RIA antibody cross reactivity with phosphorylated ZDV, samples were split into two fractions, one of which was treated with alkaline phosphatase (AP) to liberate phosphate groups. Each fraction was then assayed for ZDV. Concentrations of phosphorylated ZDV were determined by subtracting the concentration of the non-AP-treated fraction from that of the treated fraction. Recovery of phosphorylated ZDV from cell extracts was approximately 90%, and reproducibility was acceptable (coefficients of variation less than 15% for concentrations greater than or equal to 0.25 ng/ml). Intracellular concentrations (0.1-1.4 pmoles/10(6) cells) followed a nonlinear dose-response relationship over the range 0-50 microM extracellular ZDV, with concentration-dependent saturation. These results demonstrate the feasibility of determining concentrations of phosphorylated ZDV in HIV-infected patients, a potentially key step in establishing a therapeutic range and optimal dosing regimen for these patients.
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PMID:In vitro measurement of phosphorylated zidovudine in peripheral blood leucocytes. 229 12

Effects of cell fixation procedures appropriate for flow cytometric analysis on the infectivity of human T lymphoblastoid H9 cells infected with human immunodeficiency virus-1 (HIV-1) were evaluated to provide guidelines for choosing cell treatments for potentially infectious samples. H9 cells experimentally infected with HIV-1 were treated by the test fixation procedure, washed, and cocultured with equal numbers of live, uninfected H9 cells. To estimate the reduction in infectivity due to the fixation procedure, dilution series of live infected H9 cells in uninfected H9 cells were simultaneously established in culture. Cell cultures were incubated 8-10 d, harvested, and evaluated for evidence of HIV-1 infection by the presence of cell-associated HIV-1 antigens and/or by the presence of particle-associated reverse transcriptase activity in cell culture supernatants. Thirty-minute fixation with formaldehyde (1.85%), methanol (absolute), methanol:acetone (1:1), or paraformaldehyde (0.5%) reduced the infectivity of HIV-1-infected H9 cells by greater than 99.99%. To the same degree, a multi-step fixation procedure utilizing formaldehyde and ethanol was effective in reducing HIV-1 infectivity. Conversely, the erythrocyte fixative dimethylsuberimidate at 3 micrograms/ml was ineffective in reducing HIV-1 infectivity.
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PMID:Effects of cellular fixatives on human immunodeficiency virus production. 237 57

The dimethylsulfoxide extract of the Chinese medicinal herb Viola yedoensis demonstrates high inhibitory activity toward HIV-1 in vitro. The corresponding methanol extract also showed inhibitory activity but not as high as the dimethylsulfoxide extract. Anti-HIV activity in the extracts is accompanied by cytotoxicity, and we describe here the separation of the cytotoxic material from the active fraction. We also describe the procedure for isolation, purification, and separation of the active component from crude extracts of V. yedoensis as well as details of its activity against HIV-1. The UV-visible, infrared (IR) and proton nuclear magnetic resonance (NMR) data and certain other characteristics of the active compound are also presented. Initial chemical tests and the proton NMR and IR spectra indicate a high molecular weight sulphonated carbohydrate polymer, and chromatographic evidence suggests an MW between 10,000 and 15,000.
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PMID:Isolation, purification and partial characterization of an active anti-HIV compound from the Chinese medicinal herb viola yedoensis. 323 67


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