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

The plasma protein S (PS) system was studied in 120 HIV seropositive patients (CDC classification: group II: n = 35; group III: n = 6; groups IVA, IVC2 or IVE, n = 38; groups IVB, IVC1 or IVD, n = 41). Total PS antigen and C4b-binding protein (C4b-BP) values were not significantly different from control values. Free protein S levels assessed by an immunological method in the supernatant of PEG-precipitated plasma samples (PEG-fPS) were below the normal limit in 85 patients, lower values being found in patients with advanced HIV disease. No correlation was found between PEG-fPS levels and C4b-BP or total PS levels. At least 25 patients had a low functional PS value. Low functional levels of PS were found in each clinical group although there was no difference in the distribution of functional PS values among groups. Crossed immuno-electrophoresis showed an abnormal distribution of PS in some patients, but failed to confirm the marked decrease of free PS in patients with very low PEG-fPS. An impairment of the protein S system is observed in HIV-infected patients. However, the discrepancies found in some patients among the results of the various PS-related assays should lead to a cautious interpretation concerning the incidence of PS deficiency in HIV-infected patients.
 ...
PMID:Study of the protein S system in HIV-infected patients: acquired protein S deficiency or unsuitable assays? 164 7

A radioimmunoprecipitation (RIP) assay was developed to detect antibodies to the envelope glycoprotein gp120 of the human immunodeficiency virus (HIV-1). The assay, which utilized recombinant gp120 (rgp120), was quantitative, reproducible, and specific for antibodies to rgp120 or antibodies to native gp120 resulting from natural infection with HIV. Polyethylene glycol-8000 (PEG), used in the assay at a final concentration of 10% to precipitate immune complexes, was demonstrated to be effective in titering sera from different animal species. Provided samples were diluted at least 1:100, antibody titers could be determined either by the classical dilution method or by interpolation from a calibration curve prepared with a positive serum. The humoral response of animals immunized with rgp120 was monitored and a positive correlation was found between titers determined in the RIP assay and the ability of the sera to neutralize. In addition, RIP titers of HIV-positive human sera correlated very well with reactivity obtained in a commercial HIV immunoblot assay. The assay has the advantage of quantitation, fast turnaround time, and versatility.
 ...
PMID:A sensitive radioimmunoprecipitation assay for the detection and quantitation of antibodies to the envelope glycoprotein gp120 of the human immunodeficiency virus (HIV-1). 234 Feb 1

Simple polyesters derived from poly(ethylene glycol)s and alpha, omega-dicarboxylic acids exhibit a broad range of activity in disrupting phospholipid membranes. This activity has been analyzed by measuring the release of liposome-encapsulated 5(6)-carboxy-fluorescein (CF). Comparison with an analogous monomeric surfactant, and with Triton X-100, demonstrates that macromolecular activity is a sensitive function of the size of the hydrophobic and hydrophilic segments within each repeat unit, and that high disrupting power is possible. In vitro studies with the human immunodeficiency virus type-1 have revealed that those polyesters which exhibit the highest membrane disrupting power also provide significant protection for human CD4+ lymphocytes against HIV-1. The potential for adjusting and utilizing these "supramolecular surfactants" in medicine is briefly discussed.
 ...
PMID:Supramolecular surfactants: amphiphilic polymers designed to disrupt lipid membranes. 293 May 30

HIV-seropositive homosexuals, narcotic addicts and hemophiliacs develop a new syndrome of immunologic thrombocytopenic purpura (ITP) which is clinically indistinguishable from classic autoimmune thrombocytopenic purpura (ATP) with respect to increased megakaryocytes in the bone marrow, peripheral destruction of antibody-coated platelets, negative serology for SLE, response to treatment with prednisone and/or splenectomy. Eleven of 79 homosexual patients have developed AIDS 2 to 43 months after the diagnosis of ITP (mean, 22 months). The mechanism of the ITP appears to be different in homosexuals and narcotic addicts when compared to classic ATP. Homosexuals and narcotic addicts have markedly elevated platelet-bound IgG and C3C4 (2.5-4-fold ATP levels), PEG-precipitable circulating immune complexes and anti-F(ab')2 antibodies (absent in ATP). There is no inverse relationship between platelet-bound IgG and platelet count and platelet antibody is usually not elutable from washed platelets as is the case with classic ATP. Homosexual patients do not have 7S platelet antibody in their sera as do classic ATP patients, but appear to have immune complex deposition on their platelets, possibly due to the presence of anti-F(ab')2 antibodies. Narcotic addict patients do have detectable 7S platelet antibody but also appear to have immune complex deposition on their platelets, possibly due to anti-F(ab')2 antibodies. The anti-F(ab')2 antibodies are of the IgG class. They react with autologous, homologous patient and healthy control F(ab')2 fragments. Some anti-F(ab')2 antibodies have broad reactivity, others are more limited. It is postulated that some of the anti-F(ab')2 antibodies may be responsible for the thrombocytopenia.
 ...
PMID:Immunologic thrombocytopenic purpura in patients at risk for AIDS. 333 92

The ultrastructure of human immunodeficiency virus type 2 (HIV-2) was determined by negative stain and thin section electron microscopy (EM). Some virus particles had surface projections about 10 nm in length which were evenly spaced. Nonidet P40-treated particles which were penetrated by stain revealed a distinctive off-centre cone-shaped core and, in addition, free-lying cores were also seen in detergent-treated preparations. The surface of the cores was composed of a layer of small subunits. The structure of HIV-2 determined by thin section EM was the same as that deduced by negative stain EM.
 ...
PMID:Ultrastructure of human immunodeficiency virus type 2. 338 10

We have attempted to relate genetic recombination involving human immunodeficiency virus type 1 (HIV-1) to multiple drug resistance by using PEG to fuse subclones of U937 cells that carried HIV-1 recombinants resistant to either 3' -azido-3'-deoxythymidine (AZT) or the (--) enantiomer of 2',3'-dideoxy-3'-thiacytidine (3TC). The parental viruses employed contained well-defined mutations in the pol gene. Fused cells were co-cultured with the MT4 lymphocyte cell line for virus amplification to yield progeny that, in some cases, possessed different patterns of drug resistance from parental viruses. Mutational analyses were performed by PCR to substantiate these observations, which were also confirmed by direct sequencing of single strands of DNA segments, obtained from plaque-purified viruses. These studies indicate that viral recombination had occurred, and establish a theoretical basis on which to conclude that the acquisition of multiple drug resistance on the part of HIV-1 may be related to its ability to promote cell fusion.
 ...
PMID:Possible involvement of cell fusion and viral recombination in generation of human immunodeficiency virus variants that display dual resistance to AZT and 3TC. 759 65

Human immunodeficiency virus 1-related idiopathic thrombocytopenic purpura (HIV-1-ITP) patients have a 4-fold increased percentage of CD5+ B cells and a 4.8-fold increased percentage of serum immune complexes precipitated by polyethylene glycol (PEG-ICs) compared to control subjects, as reported previously. Since CD5+ B cells produce predominantly IgM rheumatoid factor (RF) vs. Fc of IgG and PEG-ICs contain high levels of IgM, we looked for the presence of RF in the immune complexes of HIV-1-ITP patients. PEG-ICs were adsorbed to protein A and dissociated with acid, and IgM and IgG were purified by gel filtration and affinity chromatography. Solid-phase ELISA was used to measure antibody specificity vs. platelets, Fc, and HIV-1 gp120, p24, and CD4. Dissociated IgG antibody reacted with platelets, HIV-1 gp120, p24, and CD4, but not with Fc. Serum IgG did not react with platelets or Fc but did react with HIV-1 gp120, p24, and CD4. Both PEG-IC IgM and serum IgM reacted with Fc as well as the other four antigens. Control IgM and IgG were unreactive. Isolated IgM from PEG-ICs relocated approximately 50% of the IgG preincubated with IgM to the Vo region of a G200 gel-filtration column. Anti-platelet IgG but not IgM could be affinity-purified from fixed platelets. Both F(ab')2 fragments of anti-platelet IgG and the total PEG-IC bound to platelets in a saturation-dependent manner. F(ab')2 of anti-platelet IgG inhibited 50% binding of PEG-IC to platelets at an F(ab')2/complex ratio of 3:1 (wt/wt). Scatchard analysis revealed two classes of binding sites: high-affinity Kd values of 0.8-1.8 nM and lower-affinity Kd values of 6.6-12.3 nM with respective numbers of binding sites of 44,000-57,000 and 122,000-256,000 (n = 4). Anti-platelet IgG of 6/6 patients precipitated GPIIIa from platelet lysates of surface 125I-labeled platelets. Platelet count correlated inversely with anti-platelet IgG (r = -0.73; P < 0.01; n = 27). Thus, PEG-ICs of HIV-1-ITP patients contain IgM RF, which sequesters serum anti-platelet IgG containing anti-GPIIIa. Anti-platelet IgG contributes to binding of immune complexes to platelets and correlates with thrombocytopenia.
 ...
PMID:Sequestration of anti-platelet GPIIIa antibody in rheumatoid factor immune complexes of human immunodeficiency virus 1 thrombocytopenic patients. 789 59

We previously described an ELISA to measure the inhibition of platelet glycoprotein IIb/IIIa (GPIIb/IIIa) binding to fibrinogen due to immune complexes and/or anti-platelet antibodies from patients with immune thrombocytopenia (ITP) or HIV-related ITP. Circulating immune complexes (CIC) were the main factor in the inhibition of GPIIb/IIIa binding to fibrinogen in HIV-related ITP, whereas in non-HIV ITP, inhibition was only partially due to CIC; anti-platelet antibodies specific to GPIIIa were also shown to play a role. In this study, we correlated the rise in the platelet count after intravenous immunoglobulin (IVIG) infusion with the decrease in inhibition of fibrinogen binding to GPIIb/IIIa by the sera of patients with ITP and HIV-related ITP. In the majority of the patients' sera tested, as the platelet count increased following the administration of IVIG, the degree of inhibition of GPIIb/IIIa binding to fibrinogen decreased. We also observed a decrease and/or disappearance of the antibodies specific to GPIIb and/or GPIIIa after IVIG administration. In HIV-seronegative ITP patients, the decrease or disappearance of anti-platelet antibodies directly correlated with the decreased inhibition of GPIIb/IIIa binding to fibrinogen by the 2% PEG supernatants of sera which contained anti-platelet antibodies. These findings suggest that IVIG directly affects the binding of CIC and anti-platelet antibodies to platelets and thereby improves platelet survival. Our results also suggest that the anti-idiotypic effect may contribute to IVIG's therapeutic action. In contrast, in the HIV-seropositive group, the decreased inhibition by PEG precipitates after IVIG administration was more strongly associated with an increase in the platelet count.
 ...
PMID:Effect of intravenous immunoglobulin on inhibition of fibrinogen binding to platelets by sera from patients with immune thrombocytopenia. 826 23

The cores of human and simian immunodeficiency viruses (HIV and SIV) were observed by negative staining after isolation of the core with Nonidet P40 and glutaraldehyde. Four kinds of cores were found: asymmetric and symmetric sectoral shapes, a bar shape, and a triangular shape. These results were confirmed by the examination of ultrathin sections of whole virions. In some virions, the connection between the core and the envelope was observed after freeze fracturing. Its structure was considered to be characteristic of an intermediate stage of viral maturation. The HIV-1 core was reacted with anti-HIV-1 p24 mouse monoclonal antibody.
 ...
PMID:Inner architecture of human and simian immunodeficiency viruses. 839 61

Calcium ions are required for fusion of a wide variety of artificial and biological membranes. To examine the role of calcium ions for cell fusion mediated by interactions between CD4 and the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (gp120-gp41), we used two experimental systems: (i) cells expressing gp120-gp41 and its receptor CD4, both encoded by recombinant vaccinia viruses, and (ii) chronically infected cells producing low levels of HIV-1. Fusion was measured by counting the number of syncytia and by monitoring the redistribution of fluorescence dyes by video microscopy. Syncytia did not form in solutions without calcium ions. Addition of calcium ions partially restored the formation of syncytia. EDTA and EGTA [ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid] blocked syncytium formation in culture media containing calcium ions. Membrane fusion as monitored by fluorescence dye redistribution also required calcium ions. Cell fusion increased with an increase in calcium ion concentration from 100 microM to 10 mM but was not affected by magnesium ions in the concentration range from 0 to 30 mM. Fibrinogen and fibronectin did not promote fusion in the absence or presence of Ca2+. Binding of soluble CD4 to gp120-gp41-expressing cells was not affected by Ca2+ and Mg2+. We conclude that Ca2+ is involved in postbinding steps in cell fusion mediated by the CD4-HIV-1 envelope glycoprotein interaction.
 ...
PMID:Calcium ions are required for cell fusion mediated by the CD4-human immunodeficiency virus type 1 envelope glycoprotein interaction. 843 34


1 2 3 4 5 6 7 8 9 10 Next >>