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

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

A free radical is any species capable of independent existence that contains one or more unpaired electrons. Free radical reactions have been implicated in the pathology of more than 50 human diseases. Radicals and other reactive oxygen species are formed constantly in the human body, both by deliberate synthesis (e.g. by activated phagocytes) and by chemical side-reactions. They are removed by enzymic and nonenzymic antioxidant defence systems. Oxidative stress, occurring when antioxidant defences are inadequate, can damage lipids, proteins, carbohydrates and DNA. A few clinical conditions are caused by oxidative stress, but more often the stress results from the disease. Sometimes it then makes a significant contribution to the disease pathology, and sometimes it does not. Several antioxidants are available for therapeutic use. They include molecules naturally present in the body [superoxide dismutase (SOD), alpha-tocopherol, glutathione and its precursors, ascorbic acid, adenosine, lactoferrin and carotenoids] as well as synthetic antioxidants [such as thiols, ebselen (PZ51), xanthine oxidase inhibitors, inhibitors of phagocyte function, iron ion chelators and probucol]. The therapeutic efficacy of SOD, alpha-tocopherol and ascorbic acid in the treatment of human disease is generally unimpressive to date although dietary deficiencies of the last two molecules should certainly be avoided. Xanthine oxidase inhibitors may be of limited relevance as antioxidants for human use. Exciting preliminary results with probucol (antiatherosclerosis), ebselen (anti-inflammatory), and iron ion chelators (in thalassaemia, leukaemia, malaria, stroke, traumatic brain injury and haemorrhagic shock) need to be confirmed by controlled clinical trials. Clinical testing of N-acetylcysteine in HIV-1-positive subjects may also be merited. A few drugs already in clinical use may have some antioxidant properties, but this ability is not widespread and drug-derived radicals may occasionally cause significant damage.
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PMID:Drug antioxidant effects. A basis for drug selection? 172 62

Plasma zinc and copper concentrations, erythrocyte zinc concentration, copper-zinc superoxide dismutase activity and urinary zinc concentrations were determined for control subjects and individuals with AIDS, ARC, or asymptomatic HIV infection. Significant differences among the population groups were not noted for the above parameters with the exception of plasma copper which was higher in the AIDS group than in other patient groups. These results do not support the idea that zinc deficiency is a common contributory factor of HIV infectivity or clinical expression, nor that HIV infection induces a zinc deficiency.
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PMID:Zinc status in human immunodeficiency virus infection. 197 59

Human immunodeficiency virus type 1 (HIV-1) is rapidly inactivated by exposure to a naturally occurring antimicrobial system consisting of peroxidase, H2O2, and a halide. Among the potential sources of H2O2 is the amine oxidase system in which mono-, di-, and polyamines are oxidatively deaminated with the formation of H2O2. The polyamine spermine is present at exceptionally high concentrations in semen. We report here that spermine, spermidine, and, to a lesser degree, the synthetic polyamine 15-deoxyspergualin are viricidal to HIV-1 when combined with amine oxidase and myeloperoxidase. Antiviral activity required each component of the spermine-amine oxidase-peroxidase system and was inhibited by azide (a peroxidase inhibitor) and by catalase but not by superoxide dismutase. Heat treatment of catalase largely abolished its inhibitory effect. These findings implicate H2O2 formed by the amine oxidase system in the antiviral effect and raise the possibility that the polyamine-amine oxidase-peroxidase system influences the survival of HIV-1 in semen and in the vaginal canal.
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PMID:Inactivation of human immunodeficiency virus type 1 by the amine oxidase-peroxidase system. 755 47

Evidence has accumulated suggesting that HIV-infected patients are under chronic oxidative stress. Perturbations to the antioxidant defense system, including changes in levels of ascorbic acid, tocopherols, carotenoids, selenium, superoxide dismutase, and glutathione, have been observed in various tissues of these patients. Elevated serum levels of hydroperoxides and malondialdehyde also have been noted and are indicative of oxidative stress during HIV infection. Indications of oxidative stress are observed in asymptomatic HIV-infected patients early in the course of the disease. Oxidative stress may contribute to several aspects of HIV disease pathogenesis, including viral replication, inflammatory response, decreased immune cell proliferation, loss of immune function, apoptosis, chronic weight loss, and increased sensitivity to drug toxicities. Glutathione may play a role in these processes, and thus, agents that replete glutathione may offer a promising treatment for HIV-infected patients. Clinical studies are underway to evaluate the efficacy of the glutathione-repleting agents, L-2-oxothiazolidine-4-carboxylic acid (OTC) and N-acetylcysteine (NAC), in HIV-infected patients.
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PMID:The role of oxidative stress in HIV disease. 759 Apr 4

Serum samples from 487 ambulatory I.V. drug users were screened for HIV and HCV antibodies to determine the prevalence of coinfection in this high risk group for AIDS. For anti-HCV antibody screening we first used a 3rd generation EIA using, as antigen synthetic peptides which were not subjected to false positive results due to antibodies against superoxide dismutase or against yeast proteins (which may copurify with the recombinant proteins employed in the first and second generation test). The specimens that were positive in the screening test were confirmed by a more specific EIA system that detect antibodies to proteins encoded by structural (HCV-st EIA) and non structural (HCV-nst-EIA) regions of the HCV genome. A second confirmation assay was also performed: sera were run in presence or absence of blocking reagents which inhibits antibodies to C200 and C22 HCV epitopes for binding to the solid phase. The sensitivity of the HCV EIA screening for human HCV antibody detection revealed a 100% positivity for HCV infection. The confirmatory strategy presented in this paper revealed an HCV EIA specificity of 98.6%. In this work we demonstrated a significantly higher prevalence (p < 0.001) of HCV exposure in HIV infected individuals compared to the general population. Our experimental data also confirmed that HBV infection in drug-users at high risk for HIV infection was significantly associated with HCV infection (p < 0.001). In contrast, the acquisition of HIV by sexual contact was not a statistically significant risk factor for HCV coinfection.
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PMID:Specificity and sensitivity of 3rd generation EIA for detection of HCV antibodies among intravenous drug-users. 768 83

Infection with a sexually transmitted disease (STD) increases the risk for human immunodeficiency virus (HIV) infection. Polymorphonuclear leukocytes (PMNs) are recruited into the genital tract by STD pathogens, such as Chlamydia trachomatis. Semen of HIV-infected men contains HIV associated with mononuclear cells. This study investigated the interaction among PMNs from HIV-uninfected persons, C. trachomatis, and HIV-infected cells and examined the mechanisms for enhanced HIV replication. We demonstrated that PMNs from HIV-seronegative donors induced HIV replication in mononuclear cells from 17 HIV-infected patients in medium without exogenous IL-2. HIV in the cell-free supernatants from cocultures of PMNs and patients' peripheral blood mononuclear cells (PBMCs) was replication competent, as indicated by their capacity to propagate HIV in a second round of culture using PBMCs from HIV-seronegative individuals and by the fact that proviral DNA was found in these cells. PMNs from HIV-seronegative donors increased HIV replication over 100-fold in chronically HIV-infected cell lines of the monocytic, T, and B cell lineages. Moreover, PMNs increased U1 cells' production of p24 antigen by as much as ninefold when compared with U1 cells cocultured with PBMCs. The addition of C. trachomatis to PMN and U1 coculture increased HIV replication by an additional ninefold at 24 h, whereas C. trachomatis alone had no effect on p24 antigen production by U1 cells. Thus, C. trachomatis serves not only to recruit PMNs, but also to interact with PMNs to increase HIV replication. HIV replication is triggered by contact of HIV-infected cells with PMNs, by the generation of reactive oxygen intermediates (ROIs), and by soluble factors such as TNF-alpha and IL-6. This is based on the findings that production of p24 antigen, IL-6, and TNF-alpha induced by PMNs is abrogated by disrupting or partitioning PMNs from HIV-infected cells; is inhibited by superoxide dismutase and catalase, enzymes that destroy ROIs; is enhanced by differentiated HL60 cells capable of producing ROIs; and is induced by PMNs tested negative for CMV. Furthermore, the production of ROIs is independent of HIV infection of mononuclear cells, since PMNs cocultured with HIV-uninfected parental monocytic and T cell lines generated ROIs. Therefore, the increased risk for acquiring HIV infection associated with chlamydia cervicitis may be related to the local recruitment of PMNs by C. trachomatis and the induction of infectious virus from mononuclear cells present in semen. These observations provide a rationale for strategies to reduce HIV transmission by control of STD.
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PMID:Neutrophils from human immunodeficiency virus (HIV)-seronegative donors induce HIV replication from HIV-infected patients' mononuclear cells and cell lines: an in vitro model of HIV transmission facilitated by Chlamydia trachomatis. 769 32

This study demonstrates that human immunodeficiency virus type 1 (HIV-1) Tat protein amplifies the activity of tumor necrosis factor (TNF), a cytokine that stimulates HIV-1 replication through activation of NF-kappa B. In HeLa cells stably transfected with the HIV-1 tat gene (HeLa-tat cells), expression of the Tat protein enhanced both TNF-induced activation of NF-kappa B and TNF-mediated cytotoxicity. A similar potentiation of TNF effects was observed in Jurkat T cells and HeLa cells treated with soluble Tat protein. TNF-mediated activation of NF-kappa B and cytotoxicity involves the intracellular formation of reactive oxygen intermediates. Therefore, Tat-mediated effects on the cellular redox state were analyzed. In both T cells and HeLa cells HIV-1 Tat suppressed the expression of Mn-dependent superoxide dismutase (Mn-SOD), a mitochondrial enzyme that is part of the cellular defense system against oxidative stress. Thus, Mn-SOD RNA protein levels and activity were markedly reduced in the presence of Tat. Decreased Mn-SOD expression was associated with decreased levels of glutathione and a lower ratio of reduced:oxidized glutathione. A truncated Tat protein (Tat1-72), known to transactivate the HIV-1 long terminal repeat (LTR), no longer affected Mn-SOD expression, the cellular redox state or TNF-mediated cytotoxicity. Thus, our experiments demonstrate that the C-terminal region of HIV-1 Tat is required to suppress Mn-SOD expression and to induce pro-oxidative conditions reflected by a drop in reduced glutathione (GSH) and the GSH:oxidized GSH (GSSG) ratio.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:HIV-1 Tat potentiates TNF-induced NF-kappa B activation and cytotoxicity by altering the cellular redox state. 785 43

N-acetyl-L-cysteine (NAC) has been proposed as a therapeutic agent for AIDS patients because it reduces human immunodeficiency virus type 1 (HIV-1) replication in stimulated T cells. However, NAC and glutathione enhanced acute HIV-1 replication in monocyte-derived macrophages. Buthionine sulfoximine did not affect NAC-mediated enhanced HIV-1 replication, indicating that the NAC-mediated effects are glutathione-independent. Superoxide dismutase and the hydroxyl radical scavengers dimethylthiourea and thiourea, but not urea, inhibited acute HIV-1 replication in macrophages. NAC reduced ferricytochrome c and increased dose-dependently Fe(III)-citrate and Fe(III)-EDTA-catalyzed hydroxyl radical formation in a system using glucose and glucose oxidase. Dimethylthiourea and thiourea, but not urea and superoxide dismutase, dose-dependently inhibited NAC-mediated enhancement of HIV-1 replication. These data suggest that oxygen radicals play an important role in self-sustained HIV-1 replication in macrophages and that oxygen radical scavengers other than NAC should be considered as therapeutic agents for AIDS patients.
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PMID:Role for oxygen radicals in self-sustained HIV-1 replication in monocyte-derived macrophages: enhanced HIV-1 replication by N-acetyl-L-cysteine. 799 46


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