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

The most important purine nucleotides (NAD, AMP, IMP, GMP, XMP, ADP, ATP, GDP, GTP) were analyzed by HPLC in the lymphocytes of healthy subjects and HIV-1 seropositive patients at different stages of the disease (ARC-AIDS). Several differences, which focus attention on the behaviour of purine nucleotide metabolism in the lymphocytes of these patients, were observed.
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PMID:Analysis of purine nucleotides in lymphocytes from healthy subjects and AIDS patients. 142 Oct 31

A quantitative coculture assay is described for determining susceptibility of HIV-1 isolates to zidovudine and sCD4 (178)-PE40 (a 60 kDa hybrid protein consisting of the gp120 binding region of CD4 linked to the translocation and ADP-ribosylation regions of Pseudomonas aeruginosa exotoxin). The assay was relatively simple to perform and gave highly reproducible results often within three to five days. IC50 values of zidovudine for HIV-1 strains isolated from two AIDS patients and an asymptomatic seropositive individual were in the range 0.001-0.002 mumol. Isolates obtained after six months of zidovudine treatment had zidovudine IC50 values of 0.01-0.5 mumol. All isolates were equally sensitive to sCD4 (178)-PE40 (IC50 1-5 micrograms/ml). HIV-1 activation in the chronically infected cell line U-1 was inhibited by sCD4 (178)-PE40 but not by zidovudine.
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PMID:Quantitative assay for testing susceptibility of HIV isolates to zidovudine and sCD4 (178)-PE40. 142 30

Productive infection of cells by human immunodeficiency virus type 1 (HIV-1) is associated with the activation state of the cell and its obligatory expression of the interleukin-2 receptor (IL-2R), the latter providing a new target for antiviral therapy. A quantitative RNA-RNA hybridization assay is employed to detect production of HIV-1 RNA and to show that two IL-2 diphtheria toxin-related fusion proteins (DAB486IL-2 and its more potent, truncated form DAB389IL-2) inhibit HIV-1 RNA production in infected cells. A mutant form of DAB486IL-2 containing a single point mutation that inactivates the adenosine diphosphate ribosyltransferase activity of the toxin does not inhibit HIV RNA production, even though the molecule binds to the IL-2R. The active fusion proteins inhibit viral RNA replication in cells infected with HIV-1 clinical isolates as well as with a ZDV-resistant strain of HIV-1. These results indicate that IL-2 receptor-targeted fusion proteins can be utilized to inhibit HIV-1 replication effectively in infected human lymphocytes.
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PMID:Inhibition of HIV-1 RNA production by the diphtheria toxin-related IL-2 fusion proteins DAB486IL-2 and DAB389IL-2. 145 29

Candida albicans and Cryptococcus neoformans are major causes of systemic fungal infections, particularly in patients with acquired immunodeficiency syndrome. Metabolic labeling studies revealed that these organisms synthesize a small number of N-myristoylproteins, the most prominent being 20-kDa ADP-ribosylation factors (Arfs). C. albicans Arf has approximately 80% identity with the essential Arf1 and Arf2 proteins of Saccharomyces cerevisiae. [3H]Myristic acid analogs with oxygen for -CH2- substitutions at C4, C6, C11, and C13 are incorporated into cellular N-myristoylproteins, phospholipids, and neutral lipids produced by these three yeasts during exponential growth at 30 degrees C in complex media. Analog- and organism-specific differences in the efficiency of labeling of proteins and lipid classes were observed. The effects of oxatetradecanoic acids with oxygen for -CH2- substitutions at C3-C13 on C. neoformans, C. albicans, and S. cerevisiae were assessed during mid-log phase growth at 30 degrees C. A single dose of 3-oxa-, 4-oxa-, 5-oxa- or 6-oxatetradecanoic acid (O3-O6, final concentration = 300 microM) was able to inhibit growth of C. neoformans in the order O4 greater than O5 greater than O3 approximately O6. The other compounds were inactive. 4-Oxatetradecanoic acid was fungicidal, producing a 10,000-fold reduction in viable cell number 1 h after administration and continued suppression of cell growth for 7 h. A clear dose response was observed over a concentration range of 100-300 microM. 4-Oxatridecanoic acid was 100-fold less potent in reducing cell viability than 4-oxatetradecanoic acid but more potent than 5-oxatridecanoic acid. O4 produced approximately 10-100-fold reductions in the viability of C. albicans and S. cerevisiae at 300-500 microM, respectively, whereas O5 and O6 were less active. Since N-myristoylation of the Pr55gag polyprotein precursor produced by human immunodeficiency virus I (HIV-I) is essential for its assembly, we also assessed the antiviral effects of 4-oxatetradecanoic acid. O4 is able to produce a 50% reduction in the replication of HIV-I in acutely infected human T-lymphocyte cell lines at a concentration of 18 microM. Together, these data suggest that (i) the position of the oxygen for methylene substitution is a critical determinant of the fungicidal activity of O4 and (ii) NMT may be an attractive therapeutic target for treating opportunistic fungal infections in patients infected with HIV-I.
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PMID:4-oxatetradecanoic acid is fungicidal for Cryptococcus neoformans and inhibits replication of human immunodeficiency virus I. 151 54

A chimeric toxin made by a genetic fusion between the DNA encoding the 389 N-terminal amino acids of diphtheria toxin and that coding for the V1 and V2 domains of human CD4 (amino acids 1-178) was produced, purified and examined for ADP ribosylation activity, gp120 binding and effects on acutely and chronically HIV infected cells. The fusion toxin DAB389CD4 possesses enzymatic activity and binds to gp120. DAB389CD4 was found to kill CEM and U937 cells infected by HIV selectively and efficiently in a dose dependent manner, however, fusion toxin treatment did not eliminate the virus from acutely infected cell cultures. In addition, treatment of chronically infected cells with DAB389CD4 rapidly led to the appearance of HIV infected cells which were resistant to the chimeric toxin. The experimental results reported here suggest that the potential use of gp120 targeted cytotoxic agents for the treatment of HIV infection should be viewed with caution.
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PMID:A recombinant diphtheria toxin related human CD4 fusion protein specifically kills HIV infected cells which express gp120 but selects fusion toxin resistant cells which carry HIV. 153 36

An international collaborative study was performed to evaluate a set of PCR reference reagents for HIV diagnosis. Twenty-six laboratories from 9 countries analysed a proficiency panel of 10 coded DNA samples using the PCR reference reagents and protocols. For comparison, these coded samples were then assessed using a laboratory's own 'in-house' reagents and methodologies. The objectives of the study were: (i) to assess inter-laboratory variation of PCR sensitivity, (ii) to evaluate the DNA 'carryover' problem and frequency of false negative results and (iii) to examine the utility of the complete set of reagents and templates to act as reference preparations for HIV PCR. Using the reference reagents, 46% of laboratories reported no false positive results in any of their assays of the negative controls. The remaining laboratories all reported a false positive result(s) in at least one assay. The overall false positive result rate for the study was 9.3%. In contrast, an overall false negative result rate of 7.4% was observed, with some laboratories recording negative results even for samples containing 10,000 molecules of target DNA. The level of absolute sensitivity may be assessed accurately only from the 12 laboratories that obtained no false positive results. All 12 laboratories detected the sample containing 10 molecules of template DNA and 9 out of the 12 laboratories detected the sample containing 1 molecule. This is in close agreement with the theoretical detection rate based on a statistical probability model for the detection of a single molecule. These characterised reference reagents were at least as sensitive as any of the 'in-house' reagents and methodologies applied, including nested PCR. The complete set of characterised reference reagents is now available for quality control assessment of HIV-1 PCR from the MRC ADP.
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PMID:An international collaborative study to assess a set of reference reagents for HIV-1 PCR. 157 30

Purified adenosine diphosphoribose transferase protein binds to RNA-DNA hybrid templates of reverse transcriptase at the DNA primer site and inhibits RT activity of HIV and MMu RTs. This action is prevented by auto-poly-ADP-ribosylation of the transferase but is reinduced by inhibitory ligands of the enzyme.
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PMID:Inhibitory binding of adenosine diphosphoribosyl transferase to the DNA primer site of reverse transcriptase templates. 171 66

The purine nucleotide content of lymphocytes of normal subjects and asymptomatic HIV-1 seropositive patients was analyzed by HPLC. An increase in IMP and a decrease in ADP, GDP, ATP and GPT were observed in the HIV-infected patients with respect to healthy subjects. The changes may depend on different factors and indicate that the virus influences purine nucleotide metabolism of the cell. The finding sheds light on the metabolic situation of the infected cell, and could be applied to monitoring the disease.
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PMID:Purine nucleotide content of lymphocytes from healthy subjects and asymptomatic HIV-1 seropositive patients. 176 29

Gene expression of human immunodeficiency virus type 1 (HIV-1) is induced not only by trans activation mediated through a gene product (tat) encoded by the virus but also by treatment of virus-carrying cells with DNA-damaging agents such as UV light. Employing an artificially constructed DNA in which the chloramphenicol acetyltransferase gene was placed under the control of the HIV-1 long terminal repeat, we analyzed the induction process in HeLa cells and found that inhibitors of poly(ADP-ribose) polymerase suppressed UV-induced HIV-1 gene expression but not tat-mediated expression. We also found that suppression occurs at the posttranscriptional level. These results indicate that HIV-1 gene expression is activated by at least two different mechanisms, one of which involves poly-ADP ribosylation. A possible new role of poly-ADP ribosylation in the regulation of specific gene expression is also discussed.
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PMID:Poly(ADP-ribose) polymerase inhibitors suppress UV-induced human immunodeficiency virus type 1 gene expression at the posttranscriptional level. 182 33

The paper deals with further search for substances modifying metabolic processes, changing the conditions of virus existence in the host cell and, consequently, possessing a certain antiviral activity. The antiviral effects of aromatic carbonic acids amides including trisubstituted benzamides and nicotinamide were tested. Five out of 8 substances tested possessed antiviral activity which might be due to their capacity to inhibit the activity of the enzymes of ADP-ribosylation. By blocking cellular processes of ADP-ribosylation, the substances under study depressed DNA capacity for reparation, inhibited differentiation and transformation of cells, i.e. had an indirect effect on reproduction of viruses. The universal nature of the processes coursing with participation of NAD(+)-dependent ADP-ribosylation suggests that the range of antiviral activity of inhibitors of mono- and poly-ADP-ribosylation would not be limited to HIV infection but would be rather wide.
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PMID:[Inhibitors of ADP ribosylation as antiviral agents: an experimental study in a model of HIV infection]. 183 8


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