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

Dithiocarbamates and iron chelators were recently considered for the treatment of AIDS and neurodegenerative diseases. In this study, we show that dithiocarbamates and metal chelators can potently block the activation of nuclear factor kappa B (NF-kappa B), a transcription factor involved in human immunodeficiency virus type 1 (HIV-1) expression, signaling, and immediate early gene activation during inflammatory processes. Using cell cultures, the pyrrolidine derivative of dithiocarbamate (PDTC) was investigated in detail. Micromolar amounts of PDTC reversibly suppressed the release of the inhibitory subunit I kappa B from the latent cytoplasmic form of NF-kappa B in cells treated with phorbol ester, interleukin 1, and tumor necrosis factor alpha. Other DNA binding activities and the induction of AP-1 by phorbol ester were not affected. The antioxidant PDTC also blocked the activation of NF-kappa B by bacterial lipopolysaccharide (LPS), suggesting a role of oxygen radicals in the intracellular signaling of LPS. This idea was supported by demonstrating that treatment of pre-B and B cells with LPS induced the production of O2- and H2O2. PDTC prevented specifically the kappa B-dependent transactivation of reporter genes under the control of the HIV-1 long terminal repeat and simian virus 40 enhancer. The results from this study lend further support to the idea that oxygen radicals play an important role in the activation of NF-kappa B and HIV-1.
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PMID:Dithiocarbamates as potent inhibitors of nuclear factor kappa B activation in intact cells. 131 83

A monoclonal antibody-based antigen capture enzyme-linked immunosorbent assay (ELISA) was developed and employed to detect p24 capsid antigen from human T-cell lymphotropic viruses type I and II (HTLV-I, HTLV-II), simian T-cell lymphotropic virus type I (STLV-I)-infected cell lines, and from mononuclear cell cocultures of HTLV-infected humans and STLV-I infected monkeys. A monoclonal antibody specific for HTLV p24 and p53 capsid antigens was coated onto 96-well microtiter plates to capture HTLV/STLV antigen. Captured antigen was then detected by the addition of a polyclonal, biotinylated human anti-HTLV-I antibody, and color developed with tetramethyl benzidine/H2O2 substrate. As little as 15 pg/ml of HTLV-I p24 antigen could be detected in this assay. Culture supernatants from HTLV-I-infected cell lines (HUT-102, MT-2, C5/MJ, HTLV-II-infected cell lines (Mo-T, Mo-B, PanG 12.1, NRA) and STLV-I-infected cell lines (Matsu, NEPC M39) were all positive in the assay. In addition, p24 was detected from peripheral blood mononuclear cell (PBMC) cocultures of 8 of 8 (100%) HTLV-I diseased patients, 14 of 20 (70%) HTLV-I and HTLV-II-infected, asymptomatic persons, and 8 of 8 (100%) STLV-I-infected, asymptomatic monkeys. Culture supernatants of cells infected with human immunodeficiency virus type (HIV-1), simian immunodeficiency virus (SIV), Chlamydia trachomatis, cytomegalovirus (CMV), herpes simplex I and II (HSV), feline leukemia virus (FELV), bovine leukemia virus (BLV), and bovine immunodeficiency virus (BIV) were all negative. Similarly, normal human peripheral blood mononuclear cells and uninfected, transformed human T cells, were also negative in the assay.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Development of a monoclonal antibody-based p24 capsid antigen detection assay for HTLV-I, HTLV-II, and STLV-I infection. 131 63

Myeloperoxidase (MPO), H2O2, and chloride form an antimicrobial system in neutrophilic polymorphonuclear leukocytes (PMN) effective against a variety of microorganisms. Normal human PMN, when stimulated with phorbol myristate acetate or opsonized zymosan, are viricidal to HIV-1. The viricidal effect was lost when chloride was replaced by sulfate and was inhibited by the peroxidase inhibitor azide and by catalase, but not by heated catalase or superoxide dismutase, implicating H2O2. Stimulated PMN from patients with chronic granulomatous disease (CGD) were not viricidal to HIV unless H2O2 or glucose oxidase (which generates H2O2) was added, and the viricidal activity of H2O2-supplemented CGD PMN was inhibited by azide, implicating endogenous MPO. Stimulated PMN from patients with hereditary MPO deficiency had decreased viricidal activity unless MPO was added, and the viricidal activity of MPO-supplemented, MPO-deficient PMN was inhibited by catalase, implicating endogenous H2O2. The data suggest that when PMN are stimulated, MPO released by degranulation reacts with H2O2 formed by the respiratory burst to oxidize chloride to a product (presumably hypochlorous acid) that is toxic to HIV-1. Our findings raise the possibility that this viricidal effect of stimulated PMN may influence the host defense against HIV-1.
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PMID:Viricidal effect of polymorphonuclear leukocytes on human immunodeficiency virus-1. Role of the myeloperoxidase system. 131 27

Human monocytes stimulated with phorbol 12-myristate 13-acetate or opsonized zymosan in vitro were viricidal to human immunodeficiency virus type 1 (HIV-1) as measured by the inability of the virus to replicate in CEM cells. Monocytes, when stimulated, release myeloperoxidase (MPO) and produce H2O2; MPO reacts with H2O2 and chloride to form hypochlorous acid, a known microbicidal agent. The viricidal activity of stimulated monocytes was inhibited by the peroxidase inhibitor azide, implicating MPO, and by catalase but not heated catalase or superoxide dismutase, implicating H2O2. Stimulated monocytes from patients with chronic granulomatous disease (CGD) or hereditary MPO deficiency were not viricidal to HIV-1 unless they were supplemented with the H2O2-generating enzyme glucose oxidase or MPO, respectively. The viricidal activity of stimulated, glucose oxidase-supplemented CGD monocytes and MPO-supplemented MPO-deficient monocytes, like that of normal stimulated monocytes, was inhibited by azide and catalase. Monocytesmaintained in culture differentiate into macrophages with loss of MPO and decreased H2O2 production. The viricidal activity of 3- to 9-day monocyte-derived macrophages was decreased unless MPO was added, whereas the loss of viricidal activity by 12-day-old monocyte-derived macrophages was not reversed by MPO unless the cells were pretreated with gamma-interferon. These findings suggest that stimulated monocytes can be viricidal to HIV-1 through the release of the MPO/H2O2/chloride system and that the decreased viricidal activity on differentiation to macrophages results initially from the loss of MPO and, with more prolonged culture, also from a decreased respiratory burst that can be overcome by gamma-interferon.
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PMID:Viricidal effect of stimulated human mononuclear phagocytes on human immunodeficiency virus type 1. 131 66

We have tested the hypothesis that cellular activation events occurring in T lymphocytes and monocytes and mediated through translocation of the transcription factor NF-kappa B are dependent upon the constitutive redox status of these cells. We used phenolic, lipid-soluble, chain-breaking antioxidants (butylated hydroxyanisole (BHA), nordihydroquairetic acid, or alpha-tocopherol (vitamin E) to show that peroxyl radical scavenging in unstimulated and PMA- or TNF-stimulated cells blocks the functions depending on NF-kappa B activation. BHA was found to suppress not only PMA- or TNF-induced, but also constitutive, HIV-enhancer activity concomitant to an inhibition of NF-kappa B binding activity in both lymphoblastoid T (J.Jhan) and monocytic (U937) cell lines. This was also true for KBF (p50 homodimer) binding activity in U937 cells. Secretion of TNF, the product of another NF-kappa B-dependent gene, was abolished by BHA in PMA-stimulated U937 cells. The anti-oxidative effect of BHA was accompanied by an increase in thiol, but not glutathione, content in stimulated and unstimulated T cell, whereas TNF stimulation itself barely modified the cellular thiol level. Oxidative stress obtained by the addition of H2O2 to the culture medium of J.Jhan or U937 cells could not by itself induce NF-kappa B activation. These observations suggest that TNF and PMA do not lead to NF-kappa B activation through induction of changes in the cell redox status. Rather, TNF and PMA can exert their effect only if cells are in an appropriate redox status, because prior modification toward reduction with BHA treatment prevents this activation. It appears that a basal redox equilibrium tending toward oxidation is a prerequisite for full activation of transduction pathways regulating the activity of NF-kappa B-dependent genes.
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PMID:Redox status of cells influences constitutive or induced NF-kappa B translocation and HIV long terminal repeat activity in human T and monocytic cell lines. 143 Nov 13

Conflicting data have been reported on ability of 3'-azido-3'-deoxythymidine (AZT) to protect mononuclear phagocytes from HIV-1 infection. We compared the antiviral potency of AZT in three types of primary human mononuclear phagocytes: peripheral blood monocytes, monocyte-derived macrophages (in vitro differentiated) and alveolar macrophages (in vivo differentiated). To establish highly-productive virus infection, purified cells (greater than 99%) from healthy donors were challenged with the macrophage-tropic HTLV-IIIBa-L strain at input multiplicities ranging from 0.05 to 20 TCID50 per cell. AZT (0.1 nM-10 microM) was added immediately after infection and either continued for the duration of the experiment or stopped 1-7 days after infection. The kinetics of HIV-1Ba-L replication were assessed by measuring p24 antigen production on days 4-28 post-infection. Continuous treatment with AZT reproducibly inhibited viral replication in a concentration-dependent manner in all three cell types. The IC90 of AZT was 0.04 microM in blood monocytes, 0.009 microM in monocyte-derived macrophages, and 0.0001 microM in alveolar macrophages (mean of 3-4 donors for each cell type). AZT was not cytotoxic at less than 10 microM as assessed by cell viability, cell protein, and interferon-gamma-activated H2O2-release. In experiments in which AZT treatment was stopped after infection, viral replication resumed after a lag of 7-14 days and increased exponentially toward control levels. This occurred despite initial inhibition of virus production to below the limit of p24 detection (approximately 50 pg/ml). These results indicate that AZT is a potent inhibitor of HIV-1 replication in primary mononuclear phagocytes regardless of the stage of cell differentiation, and that AZT is most active in tissue (alveolar) macrophages. AZT does not irreversibly block infection of mononuclear phagocytes, however, as viral replication resumes after removal of AZT.
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PMID:Anti-HIV-1 activity of 3'-azido-3'-deoxythymidine (AZT) in primary mononuclear phagocytes. 144 21

Dupuytren's contracture is a deforming, fibrotic condition of the palmar fascia which has confounded clinicians and scientists since the early descriptions by Guillaume Dupuytren in 1831. It predominantly affects elderly, male caucasians, has a hereditary predisposition and has strong associations with diabetes, alcohol consumption, cigarette smoking and HIV infection. The major morphological features are an increase in fibroblasts, particularly around narrowed fibroblasts; a finding consistent with localised ischaemia. During ischaemia, adenosine triphosphate (ATP) is converted to hypoxanthine and xanthine, and endothelial xanthine dehydrogenase to xanthine oxidase (alcohol also mediates this change, a finding of particular relevance given the association of Dupuytren's contracture with alcohol intake). Xanthine oxidase catalyses the oxidation of hypoxanthine to xanthine and uric acid with the release of superoxide free radicals (O2-), hydrogen peroxide (H2O2) and hydroxyl radicals (OH.). These free radicals are highly reactive, with half-lives in the order of milliseconds and are toxic in high concentrations. A potential for free radical generation in Dupuytren's contracture was elicited by finding a sixfold increase in hypoxanthine concentrations in Dupuytren's contracture compared with control palmar fascia. In vitro studies affirmed the toxic effects of oxygen free radicals to Dupuytren's contracture fibroblasts, but also showed that, at lower concentrations (concentrations similar to those likely to occur in Dupuytren's contracture), free radicals had a stimulatory effect on fibroblast proliferation. Cultured fibroblasts were found to release their own O2-. These endogenously released free radicals were also found to be important in fibroblast proliferation. The collagen changes of Dupuytren's contracture were examined. The results established that fibroblast origin was unimportant, but that inhibition of type I collagen production at high fibroblast density accounted for the increase in type III/I collagen ratios observed by previous investigators. These biochemical and morphological observations throw new light on Dupuytren's contracture. They suggest that age, genetic and environmental factors may contribute to micro vessel narrowing with consequent localised ischaemia and free radical generation. Endothelial xanthine oxidase derived free radicals may both damage the surrounding stroma and stimulate fibroblasts to proliferate. Proliferating fibroblasts lay down and contract collagen in lines of stress.Progressive fibroblast proliferation and deposition of collagen is likely to encourage further microvessel narrowing with a positive feedback effect consistent with the progressive nature of the condition.
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PMID:An insight into Dupuytren's contracture. 161 55

Peroxidase, H2O2, and a halide form a powerful antimicrobial system in phagocytes and tissue fluids, and certain microorganisms can serve as the source of H2O2 for this system. H2O2-generating Lactobacillus acidophilus (LB+) is present in the vagina of most normal women and peroxidase has been detected in vaginal fluid. LB+ at high concentration is viricidal to HIV-1, and, at levels where LB+ is ineffective alone, the addition of peroxidase (myeloperoxidase, eosinophil peroxidase) and a halide (chloride, iodide, bromide, thiocyanate) restore viricidal activity. LB+ can be replaced by H2O2, but not by non-H2O2-producing LB, and viricidal activity is inhibited by azide and catalase. The survival of HIV in the female genital tract and thus the likelihood of transmission may be influenced by the activity of the LB(+)-peroxidase-halide system in the vagina.
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PMID:Viricidal effect of Lactobacillus acidophilus on human immunodeficiency virus type 1: possible role in heterosexual transmission. 164 36

Hydrogen peroxide and oxygen radicals are agents commonly produced during inflammatory processes. In this study, we show that micromolar concentrations of H2O2 can induce the expression and replication of HIV-1 in a human T cell line. The effect is mediated by the NF-kappa B transcription factor which is potently and rapidly activated by an H2O2 treatment of cells from its inactive cytoplasmic form. N-acetyl-L-cysteine (NAC), a well characterized antioxidant which counteracts the effects of reactive oxygen intermediates (ROI) in living cells, prevented the activation of NF-kappa B by H2O2. NAC and other thiol compounds also blocked the activation of NF-kappa B by cycloheximide, double-stranded RNA, calcium ionophore, TNF-alpha, active phorbol ester, interleukin-1, lipopolysaccharide and lectin. This suggests that diverse agents thought to activate NF-kappa B by distinct intracellular pathways might all act through a common mechanism involving the synthesis of ROI. ROI appear to serve as messengers mediating directly or indirectly the release of the inhibitory subunit I kappa B from NF-kappa B.
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PMID:Reactive oxygen intermediates as apparently widely used messengers in the activation of the NF-kappa B transcription factor and HIV-1. 206 63

An important aspect of the infection by the human immunodeficiency virus (HIV-1) type 1 is its clinical latency, suggesting that the virus itself or the provirus may remain latent for extended periods of time after primary infection. Certain heterologous viral proteins or chemical and physical agents are able to reactivate latent virus. Since a common denominator shared by these agents is the ability to cause stress response in cells, we have examined the effects of oxidative stress mediated by hydrogen peroxide (H2O2) on HIV-1 latently infected promonocytic cell line termed U1. After exposure to H2O2 in concentrations ranging from 0.1 to 2 mM, the viability of the U1 cells decreased during 24 h before recovery. At 24 h post stress, the U1 cells began to express virus as assessed by elevated reverse transcriptase activities in culture supernatants. Immunofluorescence carried out on stressed U1 cells using anti-HIV-1 polyclonal antibodies showed that H2O2 leads to HIV-1 gene expression activation, but not to a release of viral particles from damaged cells. Additionally, using a HeLa cell line containing integrated the bacterial chloramphenicol acetyl transferase (CAT) gene under the control of the HIV-1 long terminal repeat (LTR), we have shown that oxidative stress mediated by H2O2 allows transactivation of the viral LTR revealed by intracellular CAT activity. A stimulation factor of around 4 of CAT activity can be reached when these cells are treated with 0.5 mM H2O2.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activation of human immunodeficiency virus type 1 by oxidative stress. 207 16


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