UMLS:C0021051 - FACTA Search

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Query: UMLS:C0021051 (immunodeficiency)
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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.
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PMID:Calcium ions are required for cell fusion mediated by the CD4-human immunodeficiency virus type 1 envelope glycoprotein interaction. 843 34

In vitro experiments have suggested that interleukin (IL)-6 may contribute to human immunodeficiency virus (HIV) burden and to immunological abnormalities in HIV-infected patients. We had the opportunity to directly address this question in vivo through the virological and immunological monitoring of HIV-infected patients treated with an anti-IL-6 monoclonal antibody (mAb) for a lymphoma (ANRS 018 trial). Sixteen courses of anti-IL-6 mAb administration, performed in 11 patients, were studied. All patients were at a late stage of HIV infection. The HIV load and the immunological status were determined at the initiation of each course and at its end, 21 days later. The mAb induced no significant change of HIV load, as evaluated by p24 antigenemia, plasma viremia, and quantification of circulating HIV RNA by reverse transcriptase-polymerase chain reaction and branched DNA techniques. The anti-IL-6 mAb also did not affect CD4+, CD8+, and CD19+ circulating cell counts, nor the serum concentrations of sIL-2R and of sCD8. In contrast, the mAb completely abrogated acute-phase reaction, as demonstrated by the normalization of C-reactive protein and fibrinogen circulating levels (p = 0.013 and p = 0.008, respectively). It increased serum albumin concentration. The latter effect was restricted to patients with a spontaneously low albuminemia (p = 0.01). It decreased B-lymphocyte hyperactivity, as reflected by decreased IgG and IgA serum levels (p = 0.008 and p < 0.001, respectively), and by a decreased production of IgG in vitro (p = 0.017). In contrast, the IgM hyperproduction was not affected by the mAb. Therefore, increased IL-6 production in HIV-infected patients at a late stage of the infection may not stimulate HIV replication in vivo, but it may represent a key mechanism contributing to the metabolic and immunological dysbalance of the disease.
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PMID:In vivo role of IL-6 on the viral load and on immunological abnormalities of HIV-infected patients. 852 34

Fibrinogen solutions were irradiated with UVC (254 nm) to inactivate contaminating viruses. In order to protect fibrinogen during UVC irradiation, 0.5 mM rutin was added prior to UVC exposure and subsequently removed during processing. Viral kill by 0.1 J/cm2 UVC resulted in the following inactivation values (log 10): non-lipid-enveloped viruses: Parvo > or = 5.5; encephalomyocarditis virus > or = 6.5; hepatitis A virus > or = 6.5: lipid-enveloped viruses: human immunodeficiency virus > or = 5.7; vesicular stomatitis virus > or = 5.7. Fibrinogen irradiated with 0.5 mM rutin did not significantly differ from unirradiated material in terms of clot time and breaking strength. In the absence of rutin, UVC irradiation of fibrinogen at similar fluence led to loss of solubility, increased clot time and the cleavage of fibrino-peptides that reacted with dinitrophenyl hydrazine as a test for ketonic carbonyl groups. High-performance liquid chromatography and mass spectrometry data showed that rutin exposed to UVC formed numerous breakdown, oxidation and combinational products. Experiments with 3H-rutin showed that after UVC irradiation, subsequent processing by a C18 resin and alcohol precipitation removed > 99% rutin, representing < 10 ppm rutin in the final fibrinogen preparations. Residual 3H-rutin was not covalently bonded to the fibrinogen. Immunochemical studies with rabbit antisera to UVC irradiated (with rutin) fibrinogen showed the absence of neoimmungens. By all measures, rutin prevents fibrinogen degradation during virucidal UVC irradiation.
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PMID:Protecting fibrinogen with rutin during UVC irradiation for viral inactivation. 893 67

Electron microscopy is routinely utilized in most centers in the evaluation of native renal biopsies. Several studies, primarily from the 1960s and early 1970s, provide justification for its use. Conducted by Siegel et al. (1), the largest study evaluated 213 consecutive renal biopsies and found that electron microscopy was needed for a correct diagnosis in 11%, as well as for confirmation or additional information in another 36%. However, nearly all of these studies were conducted before the use of immunofluorescence in renal biopsy diagnosis became widespread and before several new glomerular diseases and variants were described. In light of this situation and the expense of the procedure, the routine use of electron microscopy in native renal biopsies also examined by immunofluorescence and routine light microscopy was reevaluated. From January 1996 to June 1996, 288 native renal biopsies were received, and all were evaluated by the same pathologist. Of those, 233 met criteria for inclusion in this study, which were > or = 5 glomeruli for light microscopy, > or = 2 for immunofluorescence, and > or = 1 for electron microscopy, not including globally scarred glomeruli. Light microscopy (hematoxylin and eosin, periodic acid-Schiff stains) and immunofluorescence--for immunoglobulin (Ig) G, IgA, IgM, C3, C1q, fibrinogen; kappa/lambda when needed--were evaluated on each biopsy within 48 h of receipt, and a preliminary diagnosis was recorded if possible. Electron microscopy was then performed, and a final diagnosis was made. In 50 cases (21%), electron microscopy was needed to make the final diagnosis; in two of these cases, the preliminary diagnosis was incorrect, and in 48, a firm preliminary diagnosis could not be made. In the other cases, the preliminary diagnosis was correct, but in 48 (21%), ultrastructural study was felt to provide important confirmatory data, and in eight cases (3%), an additional, unrelated diagnosis was supported by the ultrastructural findings. Diagnoses most frequently requiring electron microscopy included minimal change nephropathy, early diabetic nephropathy, membranous lupus nephritis, membranoproliferative glomerulonephritis, postinfectious glomerulonephritis, thin basement membrane nephropathy (or exclusion of this in cases of otherwise unexplained hematuria), and human immunodeficiency virus-associated nephropathy (or exclusion of it in cases of collapsing glomerulopathy). Common diagnoses usually not requiring electron microscopy included IgA nephropathy, diffuse proliferative lupus nephritis, focal segmental glomerulosclerosis (not collapsing glomerulopathy variant), pauci-immune crescentic glomerulonephritis, acute interstitial nephritis, and amyloid nephropathy. This study confirms that, as was the case 20 to 30 yr ago, electron microscopy provides useful diagnostic information in nearly half of native renal biopsies. If electron microscopy cannot be performed routinely on all such biopsies, it is recommended that tissue for ultrastructural studies be set aside in each case.
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PMID:A reevaluation of routine electron microscopy in the examination of native renal biopsies. 901 50

Thrombocytopenia is a consistent finding and one of the earliest hematological abnormalities in horses acutely infected with equine infectious anemia virus (EIAV), a lentivirus closely related to human immunodeficiency virus. Multifactorial mechanisms, including immune-mediated platelet destruction and impaired platelet production, are implicated in the pathogenesis of EIAV-associated thrombocytopenia. This study was undertaken to investigate whether regenerative thrombopoiesis and platelet destruction occurred in ponies acutely infected with EIAV. Circulating large, immature platelets were increased in ponies acutely infected with EIAV late in the infection when platelet count was at a nadir. Morphometric analysis of bone marrow from acutely infected ponies revealed significant increased in megakaryocyte area and megakaryocyte nuclear area. A trend toward increased numbers of megakaryocytes was also observed. Platelets from acutely infected ponies had increased surface-bound fibrinogen and ultrastructural changes consistent with in vivo platelet activation. Platelets also had hypofunctional aggregation responses to three agonists in vitro. We conclude that thrombocytopenia in ponies acutely infected with EIAV is regenerative and suggest that bone marrow platelet production is not severely compromised in these ponies. Our findings reveal that in vivo platelet activation occurs in ponies acutely infected with EIAV, and as a result platelets are hypofunctional in vitro. Activation of platelets in vivo may cause platelet degranulation or formation of platelet aggregates, which would result in removal of these damages platelets from circulation. This may represent a form of nonimmune-mediated platelet destruction in ponies acutely infected with EIAV.
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PMID:Platelets from thrombocytopenic ponies acutely infected with equine infectious anemia virus are activated in vivo and hypofunctional. 1036 85

Three serial isolates of Candida albicans were obtained by direct swab or by oral saline rinses from each of five human immunodeficiency virus-infected patients with recurrent oropharyngeal candidiasis. Genotyping techniques confirmed the presence of a persistent strain in multiple episodes from the same patient, which was different from the strains isolated from other patients. Fluconazole susceptibility was determined by both an agar dilution method and the National Committee for Clinical Laboratory Standards macrobroth procedure. In four of these patients the strains developed fluconazole resistance, and in one patient the strain remained susceptible. The different isolates were propagated as yeast cells on a synthetic medium, and their cell wall proteinaceous components were extracted by treatment with beta-mercaptoethanol. Protein and mannoprotein components present in the extracts were analyzed by electrophoresis, immunoblotting, and lectin-blotting techniques. The analysis showed a similar composition, with only minor qualitative and quantitative differences in the polypeptidic and antigenic patterns associated with the cell wall extracts from serial isolates from the same patient, as well as those from different strains isolated from different patients. Use of monospecific antibodies generated against two immunodominant antigens during candidiasis (enolase and the 58-kDa fibrinogen-binding mannoprotein) demonstrated their expression in all isolates tested. Overall, the antigenic makeup of C. albicans strains remained constant during the course of infection and was not affected by development of fluconazole resistance. In contrast to previous reports, the low degree of antigenic variability observed in this study may be due to the fact that the isolates were obtained from a highly homogeneous population of patients and to the uniformity in techniques used for the isolation, storage, and culture of the different strains, as well as extraction methodologies.
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PMID:Low levels of antigenic variability in fluconazole-susceptible and -resistant Candida albicans isolates from human immunodeficiency virus-infected patients with oropharyngeal candidiasis. 1047 14

The blood-brain barrier (BBB) plays a critical role in regulating cell trafficking through the central nervous system (CNS) due to several unique anatomical features, including the presence of interendothelial tight junctions that form impermeable seals between the cells. Previous studies have demonstrated BBB perturbations during human immunodeficiency virus encephalitis (HIVE); however, the basis of these permeability changes and its relationship to infiltration of human immunodeficiency virus type 1 (HIV-1)-infected monocytes, a critical event in the pathogenesis of the disease, remains unclear. In this study, we examined CNS tissue from HIV-1-seronegative patients and HIV-1-infected patients, both with and without encephalitis, for alterations in BBB integrity via immunohistochemical analysis of the tight junction membrane proteins, occludin and zonula occludens-1 (ZO-1). Significant tight junction disruption (P < 0.001), as demonstrated by fragmentation or absence of immunoreactivity for occludin and ZO-1, was observed within vessels from subcortical white matter, basal ganglia, and, to a lesser extent, cortical gray matter in patients who died with HIVE. These alterations were also associated with accumulation of activated, HIV-1-infected brain macrophages, fibrinogen leakage, and marked astrocytosis. In contrast, no significant changes (P > 0.05) were observed in cerebellar tissue from patients with HIVE compared to HIV-seronegative patients or HIV-1-infected patients without encephalitis. Our findings demonstrate that tight junction disruption is a key feature of HIVE that occurs in regions of histopathological alterations in association with perivascular accumulation of activated HIV-1-infected macrophages, serum protein extravasation, and marked astrocytosis. We propose that disruption of this key BBB structure serves as the main route of HIV-1-infected monocyte entry into the CNS.
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PMID:Blood-brain barrier tight junction disruption in human immunodeficiency virus-1 encephalitis. 1059 22

Infected monocyte-derived macrophages (MDM) are thought by some investigators to play a central role in the neuropathogenesis of human immunodeficiency virus encephalitis (HIVE). It was recently proposed that these cells gain access to the central nervous system (CNS) through disruptions in blood-brain barrier (BBB) tight junctions, which occur in HIVE in association with accumulation of activated, HIV-1-infected, perivascular macrophages and serum protein extravasation (Am J Pathol 1999, 155: 1915-27). The present study tested this hypothesis in basal ganglia tissue from simian immunodeficiency virus (SIV)-infected macaques with encephalitis by examining vessels for immunohistochemical alterations in the tight junction-associated proteins, occludin and zonula occludens-1 (ZO-1). Compared to non-infected macaques and SIV-infected macaques without encephalitis, cerebral vessels from macaques with SIVE showed fragmentation and decreased immunoreactivity for both tight junction proteins. These alterations were associated with accumulation of perivascular macrophages and aberrant occludin and ZO-1 immunoreactivity within these cells. In addition, perivascular extravasation of fibrinogen, a plasma protein, and a change from a strong linear staining pattern to a more irregular pattern of glucose transporter isoform-1 (GLUT-1), a metabolic BBB marker, were observed in regions with vascular tight junction protein alterations. These findings demonstrate that tight junction disruption occurs in SIVE in association with perivascular macrophage accumulation. While it cannot be ascertained from these studies whether such changes precede macrophage infiltration, or are secondary to the chronic presence of macrophages around cerebral vessels, disruptions in BBB integrity could serve as portals for additional accumulation of perivascular macrophages in SIVE.
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PMID:Blood-brain barrier disruption in simian immunodeficiency virus encephalitis. 1105 86

Sixty-three patients with acute progressive tuberculosis (APPT) underwent splenic ultrasound radiation (SUSR) (Group 1) for evaluation of the efficiency of the procedure. A hundred and twenty five patients with APPT were treated without SUSR (Group 2, controls). An experimental study was also conducted on 290 mice. SUSR was also used in the late first month of antituberculous chemotherapy. A procedure for SUSR is described in the paper. There were most favourable clinical and X-ray changes in Group 1 than in Group 2 just after SUSR and at the end of the treatment course. After the procedure (first control) all biochemical inflammation indices (medium molecular-weight molecules, adenosine deaminase, fibrinogen, sialic acids) were significantly decreased in Group 1. Immunological indices were insignificantly changed between groups and primary investigations. A study after two months of SUSR showed no differences in biochemical indices in the groups and in this period as compared to the control one. At the same time, the levels of CD cells, especially CD8+, were found to be lower in Group 2. In Group 1, the count of CD cells and their functional activity by the blast transforming reaction on PHA were stable and significantly higher than in Group 2. The experimental study demonstrated that the levels of medium molecular-weight molecules and the index of lung damage reduced after SUSR. The decrease in the count of MBT colonies and a positive response in the murine paw test, which is indicative of T-cell immunodeficiency, were detected one month following the procedure (distant control). So SUSR should be proposed as a new effective pathogenetic treatment for APPT.
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PMID:[Effectiveness of the use of ultrasound irradiation of the spleen in patients with acutely progressive pulmonary tuberculosis]. 1222 45

Human immunodeficiency virus (HIV) is a lipid enveloped virus. The lipid envelope differs significantly from the lipid membrane of normal human cells: it contains high amounts of cholesterol, that is of importance for the virus-cell interaction (for entry and exit of the virus) at so-called lipid rafts. Cholesterol, as a R-C=C-R compound possesses an oxidazable carbenic bond. The present work suggests the inactivation of HIV by oxidation of viral cholesterol and/or unsaturated fatty acids. For oxidation, the relatively mild oxidant singlet oxygen (1O(2)) might be used. 1O(2) is generated by redoxcyclers (e.g., of the quinone type, such as vitamin K) or by chloramines (e.g., taurine-chloramine). At the 1O(2) concentrations necessary to inactivate lipid enveloped virus in human blood the oxidation-sensible critical hemostasis parameters such as thrombocytes and fibrinogen are only partly inactivated. Therefore, it is proposed to consider generators of 1O(2) as a new form of AIDS therapy.
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PMID:Singlet oxygen (1O2)-oxidazable lipids in the HIV membrane, new targets for AIDS therapy? 1261 26

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