Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A major disadvantage of conventional phototherapy is the requirement for the in situ delivery of stimulating photoenergy subsequent to the binding of photochemicals to target malignant cells, or virus-infected cells, or viruses. This drawback has resulted in considerable limitation in the use of photochemicals in photomedicine. To circumvent this problem, we have investigated the antiviral efficacy of a brominated 1,8-naphthalimide photocompound, termed LY66Br [3-bromo-4-(hexylamino)-N-hexyl-1,8-naphthalimide], which upon exposure to visible light at 420 nm generates independently of oxygen one or more stable antiviral molecular photoproducts (e.g., is 'preactivated'). Human cell lines infected with the human immunodeficiency virus type 1 (HIV-1), or with the human T-lymphotropic virus type-1 (HTLV-I) exposed to photochemical products of LY66Br (P-LY66Br) completely lost their ability to form syncytia in vitro. Photoproducts of P-LY66Br retain full antiviral activity for at least 3 and 6 weeks when stored at room temperature and at -80 degrees C, respectively. Concentrations of P-LY66Br, effective in inhibiting syncytium formation mediated by HIV-1 and HTLV-I, were nontoxic to normal red cell components of whole blood (red blood cell 2,3-diphosphoglyceric acid, adenosine triphosphate, osmotic fragility or blood type antigens). Additionally, no evidence of acute toxicity was demonstrated in mice following an intravenous bolus inoculation to achieve plasma concentration of 600 microM of P-LY66Br. These findings represent the first demonstration of inhibition of retrovirus-induced syncytium formation by a photochemical product, and justify further investigation of the preactivation process of photochemicals in the treatment of systemic viral infections such as the acquired immunodeficiency syndrome (AIDS), in cancer therapy, and in sterilization of banked blood products.
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PMID:Inhibition of retrovirus-induced syncytium formation by photoproducts of a brominated 1,8-naphthalimide compound. 784 75

We have investigated whether nutritional status and peroxidation process are associated with the degree of development of HIV infection. This was done by measuring the status of vitamins (E, A and beta-carotene), of antioxidant trace elements (zinc, selenium) and lipid peroxide levels (lipid hydroperoxides and thiobarbituric acid reactants) in HIV-seropositive patients at CDC II and CDC IV stages and in comparison with normal subjects. There was a decrease in vitamin and trace element levels related to the severity of disease. The most dramatic decrease, however, was seen for carotenoids (0.94 +/- 0.46 mumol/l) and beta-carotene (0.24 +/- 0.14 mumol/l vs. 0.56 +/- 0.29 mumol/l) whose stage II levels were only half the normal value. Paradoxically, lipid peroxidation was higher at stage II than at stage IV. This can be attributed to an overproduction of oxygen radicals by polymorphonuclears in stage II. This deficiency in antioxidant status, often found in patients suffering from peroxidative diseases, may have important consequences on cellular immunity. Furthermore, the concomitant overproduction of free radicals may also affect HIV multiplication.
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PMID:Vitamin, trace element and peroxide status in HIV seropositive patients: asymptomatic patients present a severe beta-carotene deficiency. 785 Sep 91

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

A number of carboxylic acid derivatives of the photoactive terthiophene, alpha-terthienyl, were found to possess impressive UVA-dependent activity against the human immunodeficiency virus, HIV-1; but only when assayed in the absence of serum, indicating that the latter contained interfering components. Good antiviral activity required a high rate of singlet oxygen production, in accordance with previous observations on thiophenes.
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PMID:Photoactive terthiophenes: the influence of serum on anti-HIV (human immunodeficiency virus) activities. 787 Jul 65

Monocytes, macrophages, and brain microglia are the primary cell types most readily demonstrated to be infected in CNS lesions of patients infected with HIV (Koenig et al., 1986). Microglia are implicated in mediating CNS immune regulation and neural tissue injury associated with the AIDS-dementia syndrome. This report describes the isolation and characterization of microglia from the adult human central nervous system (CNS), and the assessment of microglial immune accessory/effector functions, some of which might be altered in CNS infectious and autoimmune diseases. In our studies we have compared the in vitro properties of microglia with peripheral blood monocytes/macrophages, and with astrocytes, a CNS cell type also implicated in contributing to immune regulatory and effector functions. Additionally, we have compared phenotypic features of resident microglia in situ with monocytes and macrophages that have infiltrated the CNS during the course of CNS inflammation. Our results suggest that adult human derived parenchymal microglia represent a unique cell of monocytic origin that can be distinguished both in vitro and in situ from monocytes/macrophages recently infiltrating into the CNS and from perivascular macrophages/microglial cells. Our data demonstrate that parenchymal microglia express several immune accessory/adhesion molecules that can provide second signals for CD4+T cell stimulation. Furthermore, microglia can synthesize cytokines and reactive oxygen species that may augment ongoing pathology in the CNS of AIDS patients. Infection of resident brain microglia could augment microglial immune accessory/effector functions possibly contributing to pathology seen in HIV dementia.
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PMID:Immune regulatory and effector properties of human adult microglia studies in vitro and in situ. 787 95

A multicenter placebo-controlled trial of early short-term high-dose methylprednisolone enrolled 78 patients with moderate to severe Pneumocystis carinii pneumonia (PCP) complicating HIV infection. The mean pressure of oxygen (PO2) at study entry was 55 mm Hg for the 71 patients who had blood gases monitored while breathing room air. Patients were randomized to receive methylprednisolone (40 mg) or placebo parenterally twice daily for 10 days, and the first dose of study medication was given within 24 h of the first dose of antimicrobial therapy for PCP. The primary end point included death, need for mechanical ventilation for > 6 days, or a partial PO2 < 70 mm Hg while breathing room air 10 days after initiation of treatment. There was no statistically significant difference in the primary end point between patients randomized to corticosteroid (CS) or placebo (PL) (p = 0.522; 95% CI = -0.30, 0.16). The incidence of superinfections during therapy or of other HIV-associated infections or malignancies in the 6 months following treatment for PCP was not significantly different between the two groups. More patients randomized to placebo had to discontinue treatment with trimethoprim-sulfamethoxazole because of hypersensitivity than those randomized to corticosteroids (p = 0.039). We conclude that addition of corticosteroids does not significantly affect the outcome of PCP in patients with HIV and a PO2 < 70 mm Hg on room air at presentation but lowers the incidence of hypersensitivity reactions to trimethoprim-sulfamethoxazole.
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PMID:A multicenter randomized double-blind placebo-controlled trial of adjunctive corticosteroids in the treatment of Pneumocystis carinii pneumonia complicating the acquired immune deficiency syndrome. 788 98

Pneumocystis carinii pneumonia (PCP) has been the most common reason for hospitalization and the most common cause of death for persons with HIV infection. Hospital mortality rates for PCP range from 10 to 60%. Studies that evaluate differences in hospital mortality rates must control for differences in patient severity of illness. We developed a simple staging system for categorizing severity of illness in patients with PCP. We analyzed the relation between clinical factors and in-hospital mortality for 576 hospitalized patients with HIV-related PCP treated at 56 hospitals for the years 1987 to 1990. Four stages of PCP could be identified based on three routinely measured clinical variables: alveolar-arterial oxygen difference, total lymphocyte count, and body mass index. The mortality rate increased by stage: 1% for Stage 1, 8% for Stage 2, 23% for Stage 3, and 48% for Stage 4. The four-stage severity system compared well with previous models developed for AIDS and for PCP, and is easier to use in clinical practice. Our staging system identifies patients with a high and low risk of in-hospital death upon admission. Physicians may benefit from consideration of PCP stage in deciding on management strategies. In addition, researchers involved in clinical trials of new agents for PCP might consider stratification by PCP stage in order to define homogenous groups.
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PMID:A rapid preadmission method for predicting inpatient course of disease for patients with HIV-related Pneumocystis carinii pneumonia. 795 7

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

During various biological processes as inflammation or septic shock, free radical damages are produced by a direct production of oxygen radicals by phagocytes, but also by a TNF-mediated generation in target cells. Antioxidants have been demonstrated as protective against TNF cytotoxicity. We try to measure directly the free radical produced by murine recombinant TNF on L929 cells, by detecting the direct light produced by decomposition of superoxide using an adapted chemiluminometer. We measure also the chemiluminescence after addition of luminol. These techniques demonstrate the effective production of oxygen radicals. Unfortunately they have a rather poor specificity and sensitivity. So we use the protective effect of antioxidants on cytotoxicity to investigate the origin of the productive mechanism. We evaluate cytotoxicity of 1 U/ml TNF on L929 murine fibroblasts after 24 hours incubation with actinomycin D by the MTT and Cr51 release. Using the MTT test we observe that addition of thiourea or catalase has the better protecting effect when Zu-Zn SOD had few effect. Reversely using the Cr51 release we observe a good protective effect of Cu-Zn SOD simultaneously with a good protective effect of catalase. So the difference in the effect of various antioxidant agent do not permit to identify the species generated, but depend more on the ability of the antioxidant to reach the cell compartment tested by the method (membrane, or mitochondria). The oxidative effect of TNF is beneficial in physiological condition to destroy cancerous or virus infested cells infested by virus inside the body. But this effect can be deleterious in situation of deficiency in some antioxidant. TNF-induced free radicals can increase the replication of virus as HIV-1 and destroy immunocompetent cells as T cells. This last action explains the defect in cellular immunity observed in oxidative stress and the immunostimulatory effect of many antioxidants.
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PMID:[Tumor necrosis factor (TNF) and oxygen free radicals: potential effects for immunity]. 801 9

The HIV-1 regulatory proteins tat and rev are both RNA binding proteins which recognize sequences in duplex RNA which are close to structural distortions. Here we identify phosphate contacts which are critical for each binding reaction by use of a new method. Model RNA binding sites are constructed carrying substitutions of individual phosphodiesters by uncharged methylphosphonate derivatives isolated separately as Rp and Sp diastereoisomers and tested for protein binding by competition assays. In the binding of tat to the trans-activation response region (TAR), three phosphates, P21 and P22 which are adjacent to the U-rich bulge and P40 on the opposite strand, are essential and in each case both isomers inhibit binding. Similarly, in the interaction between the HIV-1 rev protein and the rev-responsive element (RRE) both methylphosphonate isomers at P103, P104, P124 and P125 interfere with rev binding. At P106, only the Rp methylphosphonate isomer is impaired in rev binding ability and it is proposed that the Rp oxygen is hydrogen-bonded to an uncharged amino acid or to a main chain hydrogen atom. Synthetic chemistry techniques also provide evidence for the conformations of non-Watson-Crick G106:G129 and G105:A131 base-pairs in the RRE 'bubble' structure upon rev binding. Almost all functional groups on the 5 bulged residues in the bubble have been ruled out as sites of contact with rev but, by contrast, the N7-positions of each G residue in the flanking base-pairs are identified as sites of likely hydrogen-bonding to rev. The results show that both tat and rev recognize the major groove of distorted RNA helixes and that both proteins make specific contacts with phosphates which are displaced from the sites of base-pair contact.
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PMID:Methylphosphonate mapping of phosphate contacts critical for RNA recognition by the human immunodeficiency virus tat and rev proteins. 804 22


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