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Evaluation of enzyme-linked immunosorbent and alternative assays for detection of HIV antibodies using panels of Brasilian sera

Ivo-Dos-Santos,Jairo; Mello,Deise L. Campos; Couto-Fernandez,José C.; Passos,Roberto M.; Dias-Carneiro,Leila A.; Castilho,Euclides A.; Galvão-Castro,Bernardo
Fonte: Instituto de Medicina Tropical Publicador: Instituto de Medicina Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/1990 EN
Relevância na Pesquisa
56.04%
Sera from 472 Brazilian subjects, confirmed to be either positive or negative for HIV antibodies and comprising the total clinical spectrum of HIV infection, were utilized in the evaluation of six commercially available enzyme-linked immunosorbent assays (ELISA), as well as of four alternative assays, namely indirect immunofluorescence (IIF), passive hemagglutination (PHA), dot blot and Karpas AIDS cell test. The sensitivities ranged from 100% (Abbott and Roche ELISA) to 84.2% (PHA) and the specificities ranged from 99.3% (IIF) to 80.2% (PHA). The sensitivity and specificity of the PHA and the sensitivity of the Karpas cell test were significantly lower than those of the other tests. Although the IFF and dot blot had good sensitivities and specificities, the six ELISA were more attractive than those tests when other parameters such as ease of reading and duration of assay were considered.

Positivity of HIV, hepatitis B and hepatitis C in patients enrolled in a confidential self-exclusion system of blood donation: a cross-sectional analytical study

Kasraian,Leila; Tavasoli,Alireza
Fonte: Associação Paulista de Medicina - APM Publicador: Associação Paulista de Medicina - APM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2010 EN
Relevância na Pesquisa
46.06%
CONTEXT AND OBJECTIVE: Selection of healthy blood donors is essential to ensure blood safety. A confidential self-exclusion (CSE) system was designed so that high-risk donors could confidentially exclude their blood from use in transfusions. This study aimed to compare the demographic characteristics and the results from human immunodeficiency virus (HIV), hepatitis B surface (HBS) and hepatitis C virus (HCV) screening tests on donors who opted to get into and out of CSE. DESIGN AND SETTING: Analytical cross-sectional study on all volunteer donors at Shiraz Blood Transfusion Organization from March 21, 2006, to March 21, 2008. METHODS: The results from the abovementioned tests were compared between donors who opted into and out of CSE. RESULTS: 100,148 donors in 2006 and 104,271 in 2007 gave blood. Among these donors, respectively, 829 (0.82%) and 592 (0.57%) opted for the CSE. The prevalence of HIV antibodies, HBS antigens and HCV antibodies in CSE donors was significantly higher than in donors who did not choose CSE (p < 0.05). The prevalence of at least one of these three infections among CSE donors was 3.12% in 2006 and 3.04% in 2007, and was significantly higher than the prevalence among non-CSE donors (0.58% and 0.57%, respectively). CONCLUSION: Because of the higher prevalence of HBS...

Study on the stability of internal quality control sera for HIV/AIDS immunodiagnostic tests

Castejon,Márcia Jorge; Yamashiro,Rosemeire; Oliveira,Camila Cardoso de; Granato,Daniel; Oliveira,Carmem Aparecida de Freitas; Ueda,Mirthes
Fonte: Sociedade Brasileira de Patologia Clínica; Sociedade Brasileira de Patologia; Sociedade Brasileira de Citopatologia Publicador: Sociedade Brasileira de Patologia Clínica; Sociedade Brasileira de Patologia; Sociedade Brasileira de Citopatologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2014 EN
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56.1%
Introduction: The use of reference materials in order to assure and perform the quality control of analytical measurements is a requirement in clinical laboratories. Objectives: Stability of serum samples, kept frozen at -20°C for long-term storage and at varied temperatures during short periods, was evaluated by investigating the persistency of anti-human immunodeficiency virus (HIV) antibodies reactivity on enzyme-linked immunosorbent assay/enzyme immunoassay (ELISA/EIA), Western blot and indirect immunofluorescence assays. Method: The analyzed sera were part of serum panels (comprised of anti-HIV positive and negative samples), produced at the Immunology Center of Instituto Adolfo Lutz, which have been the reference specimens for producing the internal quality assurance sera of HIV/acquired immunodeficiency syndrome (AIDS) immunodiagnostic assays. Sera stability was assessed in samples stored at -20°C for 56 weeks, and at various temperature conditions: from 2°C to 8°C (refrigerator), from 15°C to 25°C (room temperature), at 37°C (incubator) and at -80°C (freezer) for 24 and 48 hours. The statistical analyses on HIV-negative serum samples (long-term storage) were significant (p < 0.05)...

Stability of anti-HIV antibodies in serum samples stored for two to eighteen years periods

Castejon,Marcia Jorge; Yamashiro,Rosemeire; Oliveira,Camila Cardoso de; Oliveira,Carmem Aparecida de Freitas; Ueda,Mirthes
Fonte: Sociedade Brasileira de Patologia Clínica; Sociedade Brasileira de Patologia; Sociedade Brasileira de Citopatologia Publicador: Sociedade Brasileira de Patologia Clínica; Sociedade Brasileira de Patologia; Sociedade Brasileira de Citopatologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2014 EN
Relevância na Pesquisa
66.27%
Introduction: The antibodies have an important role in the serodiagnosis, constituting the most widely used biomarkers to detect and confirm various diseases. Objective: To investigate the reproducibility of anti-human immunodeficiency virus (HIV) antibodies reactivity, to assess the stability of the sera samples stored at -20ºC for two to eighteen years. Method: Sera were collected in the period 1988-2004 for routine anti-HIV antibodies diagnostic testing. The remaining samples stored at -20ºC, were analyzed in this study. Serum sample stability was assessed by enzyme-linked immunosorbent assay/enzyme immunoassay (ELISA/EIA), indirect immunofluorescence assay (IFA), and Western blot (WB) for detecting anti-HIV antibodies. The previously found results (1988-2004) and those obtained in 2006 were subjected to Kappa index analysis. Result: In the period 1988-to 2004, the degree of concordance of the ELISA/EIA, IFA and WB results were considered, good (k = 0.80), regular (k = 0.35), and good (k = 0.63), respectively. Conclusion: Regarding HIV serologic test, the serum samples were stable for 18 years in ELISA/EIA and for 4 years in IFA technique, however, for the WB methodology it was not possible to determine the time of stability of the anti-HIV antibodies.

Anti-HIV antibodies in the CSF of AIDS patients: a serological and immunoblotting study.

Bukasa, K S; Sindic, C J; Bodeus, M; Burtonboy, G; Laterre, C; Sonnet, J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1988 EN
Relevância na Pesquisa
46.2%
CSF and serum samples from 16 AIDS patients were tested for the presence of anti-HIV antibodies either by classical serological methods or by an immunoblot technique based on agarose gel isoelectric focusing and transfer of the specific IgG antibodies onto HIV antigens-loaded nitrocellulose sheets. This method enabled the demonstration of an intrathecal synthesis of anti-HIV oligoclonal IgG antibodies, often superimposed on diffuse polyclonal production, in 14 patients. The two negative cases were devoid of neurological signs or symptoms. However, two patients classified in stage II of the disease (asymptomatic infection) displayed an intrathecal synthesis of anti-HIV antibodies.

Accessing the human repertoire for broadly neutralizing HIV antibodies

Hammond, Philip W
Fonte: Landes Bioscience Publicador: Landes Bioscience
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
46.22%
The human antibody response has special significance in the ongoing efforts to develop a protective HIV vaccine. The observation that a subset of HIV infected individuals, who do not develop AIDS, have a broadly neutralizing antibody response has drawn attention to deciphering the nature of this response. It is hoped that an understanding of these protective antibodies, developed over time in response to the ongoing accumulation of mutations in the infecting virus, will facilitate the development of a vaccine that can elicit a similar response. This strategy will be greatly aided by the identification of broadly neutralizing monoclonal HIV antibodies from infected individuals. Several methods have been utilized to isolate and characterize individual antibodies from the human repertoire and each of these methods has been applied to the generation of broadly neutralizing HIV antibodies, albeit with differing rates of success. This review describes several of these methods including human hybridoma; EBV transformation; nonimmortalized B cell culture; clonal sorting; and combinatorial display. Key considerations used in the comparison of different methods includes: efficiency of interrogation of an individual’s entire repertoire; assay formats that can be used to screen for antibodies of interest (i.e....

Sequence and Structural Convergence of Broad and Potent HIV Antibodies That Mimic CD4 Binding

Scheid, Johannes F.; Mouquet, Hugo; Ueberheide, Beatrix; Diskin, Ron; Klein, Florian; Oliveira, Thiago Y. K.; Pietzsch, John; Fenyo, David; Abadir, Alexander; Velinzon, Klara; Hurley, Arlene; Myung, Sunnie; Boulad, Farid; Poignard, Pascal; Burton, Dennis
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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46.25%
Passive transfer of broadly neutralizing HIV antibodies can prevent infection, which suggests that vaccines that elicit such antibodies would be protective. Thus far, however, few broadly neutralizing HIV antibodies that occur naturally have been characterized. To determine whether these antibodies are part of a larger group of related molecules, we cloned 576 new HIV antibodies from four unrelated individuals. All four individuals produced expanded clones of potent broadly neutralizing CD4-binding-site antibodies that mimic binding to CD4. Despite extensive hypermutation, the new antibodies shared a consensus sequence of 68 immunoglobulin H (IgH) chain amino acids and arise independently from two related IgH genes. Comparison of the crystal structure of one of the antibodies to the broadly neutralizing antibody VRC01 revealed conservation of the contacts to the HIV spike.

Mouse marginal zone B cells harbor specificities similar to human broadly neutralizing HIV antibodies

Pujanauski, Lindsey M.; Janoff, Edward N.; McCarter, Martin D.; Pelanda, Roberta; Torres, Raul M.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
EN
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46.28%
A series of potent, broadly neutralizing HIV antibodies have been isolated from B cells of HIV-infected individuals. VRC01 represents a subset of these antibodies that mediate neutralization with a restricted set of IGHV genes. The memory B cells expressing these antibodies were isolated years after infection; thus, the B-cell subpopulation from which they originated and the extent of participation in the initial HIV antibody response, if any, are unclear. Here we evaluated the frequency of anti-gp120 B cells in follicular (FO) and marginal zone (MZ) B-cell compartments of naïve WT mice and comparable human populations in uninfected individuals. We found that in non–HIV-exposed humans and mice, the majority of gp120-reactive B cells are of naïve and FO phenotype, respectively. Murine FO B cells express a diverse antibody repertoire to recognize gp120. In contrast, mouse MZ B cells recognize gp120 less frequently but preferentially use IGHV1-53 to encode gp120-specific antibodies. Notably, IGHV1-53 shows high identity to human IGHV1-2*02, which has been repeatedly found to encode broadly neutralizing mutated HIV antibodies, such as VRC01. Finally, we show that human MZ-like B cells express IGHV1-2*02, and that IGHV1-53 expression is enriched in mouse MZ B cells. These data suggest that efforts toward developing an HIV vaccine might consider eliciting protective HIV antibody responses selectively from alternative B-cell populations harboring IGHV gene segments capable of producing protective antibodies.

Contribution of VH replacement products to the generation of anti-HIV antibodies

Liao, Hongyan; Guo, Jun-tao; Lange, Miles D.; Fan, Run; Zemlin, Michael; Su, Kaihong; Guan, Yongjun; Zhang, Zhixin
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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46.25%
VH replacement occurs through RAG-mediated secondary recombination to change unwanted IgH genes and diversify antibody repertoire. The biological significance of VH replacement remains to be explored. Here, we show that VH replacement products are highly enriched in IgH genes encoding anti-HIV antibodies, including anti-gp41, anti-V3 loop, anti-gp120, CD4i, and PGT antibodies. In particular, 73% of the CD4i antibodies and 100% of the PGT antibodies are encoded by potential VH replacement products. Such frequencies are significantly higher than those in IgH genes derived from HIV infected individuals or autoimmune patients. The identified VH replacement products encoding anti-HIV antibodies are highly mutated; the VH replacement “footprints” within CD4i antibodies preferentially encode negatively charged amino acids within the IgH CDR3; many IgH encoding PGT antibodies are likely generated from multiple rounds of VH replacement. Taken together, these findings uncovered a potentially significant contribution of VH replacement products to the generation of anti-HIV antibodies.

The Effects of Somatic Hypermutation on Neutralization and Binding in the PGT121 Family of Broadly Neutralizing HIV Antibodies

Sok, Devin; Laserson, Uri; Laserson, Jonathan; Liu, Yi; Vigneault, Francois; Julien, Jean-Philippe; Briney, Bryan; Ramos, Alejandra; Saye, Karen F.; Le, Khoa; Mahan, Alison; Wang, Shenshen; Kardar, Mehran; Yaari, Gur; Walker, Laura M.; Simen, Birgitte B.;
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.06%
Broadly neutralizing HIV antibodies (bnAbs) are typically highly somatically mutated, raising doubts as to whether they can be elicited by vaccination. We used 454 sequencing and designed a novel phylogenetic method to model lineage evolution of the bnAbs PGT121–134 and found a positive correlation between the level of somatic hypermutation (SHM) and the development of neutralization breadth and potency. Strikingly, putative intermediates were characterized that show approximately half the mutation level of PGT121–134 but were still capable of neutralizing roughly 40–80% of PGT121–134 sensitive viruses in a 74-virus panel at median titers between 15- and 3-fold higher than PGT121–134. Such antibodies with lower levels of SHM may be more amenable to elicitation through vaccination while still providing noteworthy coverage. Binding characterization indicated a preference of inferred intermediates for native Env binding over monomeric gp120, suggesting that the PGT121–134 lineage may have been selected for binding to native Env at some point during maturation. Analysis of glycan-dependent neutralization for inferred intermediates identified additional adjacent glycans that comprise the epitope and suggests changes in glycan dependency or recognition over the course of affinity maturation for this lineage. Finally...

Identification of broadly neutralizing antibody epitopes in the HIV-1 envelope glycoprotein using evolutionary models

Lacerda, Miguel; Moore, Penny L; Ngandu, Nobubelo K; Seaman, Michael; Gray, Elin S; Murrell, Ben; Krishnamoorthy, Mohan; Nonyane, Molati; Madiga, Maphuti; Wibmer, Constantinos Kurt; Sheward, Daniel; Bailer, Robert T; Gao, Hongmei; Greene, Kelli M; Karim,
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
46.17%
Background: Identification of the epitopes targeted by antibodies that can neutralize diverse HIV-1 strains can provide important clues for the design of a preventative vaccine. Methods: We have developed a computational approach that can identify key amino acids within the HIV-1 envelope glycoprotein that influence sensitivity to broadly cross-neutralizing antibodies. Given a sequence alignment and neutralization titers for a panel of viruses, the method works by fitting a phylogenetic model that allows the amino acid frequencies at each site to depend on neutralization sensitivities. Sites at which viral evolution influences neutralization sensitivity were identified using Bayes factors (BFs) to compare the fit of this model to that of a null model in which sequences evolved independently of antibody sensitivity. Conformational epitopes were identified with a Metropolis algorithm that searched for a cluster of sites with large Bayes factors on the tertiary structure of the viral envelope. Results: We applied our method to ID50 neutralization data generated from seven HIV-1 subtype C serum samples with neutralization breadth that had been tested against a multi-clade panel of 225 pseudoviruses for which envelope sequences were also available. For each sample...

Heterologous prime-boost-boost immunisation of Chinese cynomolgus macaques using DNA and recombinant poxvirus vectors expressing HIV-1 virus-like particles

Bridge, S.H.; Sharpe, S.A.; Dennis, M.J.; Dowall, S.D.; Getty, B.; Anson, D.S.; Skinner, M.A.; Stewart, J.P.; Blanchard, T.J.
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
46.15%
BACKGROUND: There is renewed interest in the development of poxvirus vector-based HIV vaccines due to the protective effect observed with repeated recombinant canarypox priming with gp120 boosting in the recent Thai placebo-controlled trial. This study sought to investigate whether a heterologous prime-boost-boost vaccine regimen in Chinese cynomolgus macaques with a DNA vaccine and recombinant poxviral vectors expressing HIV virus-like particles bearing envelopes derived from the most prevalent clades circulating in sub-Saharan Africa, focused the antibody response to shared neutralising epitopes. METHODS: Three Chinese cynomolgus macaques were immunised via intramuscular injections using a regimen composed of a prime with two DNA vaccines expressing clade A Env/clade B Gag followed by boosting with recombinant fowlpox virus expressing HIV-1 clade D Gag, Env and cholera toxin B subunit followed by the final boost with recombinant modified vaccinia virus Ankara expressing HIV-1 clade C Env, Gag and human complement protein C3d. We measured the macaque serum antibody responses by ELISA, enumerated T cell responses by IFN-γ ELISpot and assessed seroneutralisation of HIV-1 using the TZM-bl β-galactosidase assay with primary isolates of HIV-1. RESULTS: This study shows that large and complex synthetic DNA sequences can be successfully cloned in a single step into two poxvirus vectors: MVA and FPV and the recombinant poxviruses could be grown to high titres. The vaccine candidates showed appropriate expression of recombinant proteins with the formation of authentic HIV virus-like particles seen on transmission electron microscopy. In addition the b12 epitope was shown to be held in common by the vaccine candidates using confocal immunofluorescent microscopy. The vaccine candidates were safely administered to Chinese cynomolgus macaques which elicited modest T cell responses at the end of the study but only one out of the three macaques elicited an HIV-specific antibody response. However...

Performance evaluation of a new fourth-generation HIV combination antigen-antibody assay

Mühlbacher, A; Schennach, H; van Helden, J; Hebell, T; Pantaleo, G; Bürgisser, P; Sousa, JG, et al.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em //2013 ENG
Relevância na Pesquisa
46.15%
Education and diagnostic tests capable of early detection represent our most effective means of preventing transmission of human immunodeficiency virus (HIV). The importance of early detection is underlined by studies demonstrating increased life expectancy following early initiation of antiviral treatment. The Elecsys(®) HIV combi PT assay is a fourth-generation antigen-antibody combination assay developed to allow earlier detection of seroconversion, and to have increased sensitivity and improved specificity. We aimed to determine how early the assay could detect infection compared with existing assays; whether all HIV variants could be detected; and the assay's specificity using samples from blood donors, routine specimens, and patients with potential cross-reacting factors. Samples were identified as positive by the Elecsys(®) assay 4.9 days after a positive polymerase chain reaction result (as determined by the panel supplier), which was earlier than the 5.3-7.1 days observed with comparators. The analytical sensitivity of the Elecsys(®) HIV combi PT assay for the HIV-1 p24 antigen was 1.05 IU/mL, which compares favorably with the comparator assays. In addition, the Elecsys(®) assay identified all screened HIV subtypes and displayed greater sensitivity to HIV-2 homologous antigen and antibodies to HIV-1 E and O and HIV-2 than the other assays. Overall...

Is an HIV vaccine possible?

Wilson,Nancy A.; Watkins,David I.
Fonte: Brazilian Society of Infectious Diseases Publicador: Brazilian Society of Infectious Diseases
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2009 EN
Relevância na Pesquisa
46.31%
The road to the discovery of a vaccine for HIV has been arduous and will continue to be difficult over the ensuing twenty years. Most vaccines are developed by inducing neutralizing antibodies against the target pathogen or by using attenuated strains of the particular pathogen to engender a variety of protective immune responses. Unfortunately, simple methods of generating anti-HIV antibodies have already failed in a phase III clinical trial. While attenuated SIV variants work well against homologous challenges in non-human primates, the potential for reversion to a more pathogenic virus and recombination with challenge viruses will preclude the use of attenuated HIV in the field. It has been exceedingly frustrating to vaccinate for HIV-specific neutralizing antibodies given the enormous diversity of the Envelope (Env) glycoprotein and its well-developed glycan shield. However, there are several antibodies that will neutralize many different strains of HIV and inducing these types of antibodies in vaccinees remains the goal of a vigorous effort to develop a vaccine for HIV based on neutralizing antibodies. Given the difficulty in generating broadly reactive neutralizing antibodies, the HIV vaccine field has turned its attention to inducing T cell responses against the virus using a variety of vectors. Unfortunately...

Rol de los eritrocitos en la patogenia de HIV-1; Role of erythrocytes in the pathogenesis of HIV-1

García, María Noé
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2011 SPA
Relevância na Pesquisa
46.17%
La relación entre HIV y las células CD4 positivas en las que replica ha sido ampliamente estudiado. Sin embargo el virus puede asociarse extracelularmente a células CD4 negativas incluyendo los eritrocitos. Si bien se ha reportado que el HIV se une a eritrocitos de individuos HIV negativos in vitro y es capaz de trans-infectar a otras células, no hay estudios equivalentes utilizando eritrocitos de individuos infectados. Esta tesis aporta información sobre la población viral asociada a eritrocitos en pacientes infectados por HIV y del rol que esta población podría tener en la fisiopatología de la infección. En la misma, se demostró la asociación de RNA y antígeno viral de HIV con eritrocitos de individuos infectados cursando distintos estadios virológicos de la infección. Incluso en individuos con carga viral plasmática indetectable por un año en los cuales la detección de antígeno podría ser útil para detectar rebrote de la replicación. Por primera vez se han detectado anticuerpos anti-HIV específicos asociados a eritrocitos. La presencia de los mismos estuvo asociada con replicación viral activa. Se demostró que la capacidad de los eritrocitos de pacientes infectados de capturar virus es muy superior a la de eritrocitos de individuos no infectados. A su vez...

Fast electrochemical detection of anti-HIV antibodies: Coupling allosteric enzymes and disk microelectrode arrays

Laczka, Olivier; Ferraz, Rosa M.; Ferrer-Miralles, Neus; Villaverde Corrales, Antonio Pedro; Muñoz, F. Xavier; Campo García, Francisco Javier del
Fonte: Conselho Superior de Investigações Científicas Publicador: Conselho Superior de Investigações Científicas
Tipo: Artículo Formato: 318552 bytes; application/pdf
ENG
Relevância na Pesquisa
56.23%
6 pages, 5 figures, 1 table.-- PMID: 19393360 [PubMed].-- Printed version published May 8, 2009.; Here a novel electrochemical method for the rapid detection of anti-HIV antibodies in serum is presented. The novelty lies in the combination of allosteric enzymes and coulometry to yield a fast, simple and reliable HIV diagnostic method. We have used a previously developed β-galactosidase enzyme that is efficiently activated by anti-HIV antibodies directed against a major B-cell epitope of the gp41 glycoprotein. When these antibodies bind the enzyme, the 3D conformation changes positively affecting the performance of the active site and, consequently, the enzyme activity is stimulated. Using 4-aminophenyl β-d-galactopyranoside (PAPG) as substrate yields p-aminophenol (PAP), which is reversibly oxidised at a very mild potential, ca. 0.37 V vs. Ag/AgCl over a range of electrode materials within the working pH range of β-galactosidase. In the present case, photolithographically produced microelectrode arrays resulted in a detection limit of 4 μM for 4-aminophenol (PAP). The presence of anti-HIV antibodies results in enzyme activity increases above 50% which, combined with the sensitivity and response time afforded by the microelectrode arrays...

Reduction of HIV-virion Transport for Prevention of HIV Transmission

Lai, Bonnie E.
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação Formato: 10068797 bytes; application/pdf
Publicado em //2010 EN_US
Relevância na Pesquisa
46.24%

This dissertation explores strategies for reducing HIV-virion transport to mucosal surfaces to prevent HIV infection. Infection requires contact between HIV and an infectable cell, so any means of inhibiting this step could contribute to HIV prevention. Our goals were to quantify the effects of strategies that reduce transport of HIV virions and to evaluate them in the context of HIV prevention. We used fundamental transport theory to design two basic strategies: (1) modifying the effective radius of virions; and (2) modifying the native medium through which virions diffuse. We proposed to implement these strategies using (1) anti-HIV antibodies that would bind and aggregate virions and (2) topically-applied semi-solid gels that coat vaginal epithelial surfaces.

We measured diffusion coefficients of HIV virions and HIV-like particles in the presence of antibodies and within semi-solid gels. In experiments with antibodies, we did not observe reductions in the diffusion coefficients. In experiments using particle tracking to measure the diffusion coefficients of virions in vaginal gels, we found that the diffusion coefficients in gels were approximately 10,000 times lower than those in water.

We proceeded to evaluate the potential for semi-solid gels to prevent HIV transmission at mucosal surfaces. From previous experiments in our lab that characterized the topical deployment of vaginal gels in vivo...

Inquérito sorológico para a detecção de anticorpos contra o vírus da Imunodeficiência Humana (VIH) em crianças internadas em enfermaria geral; A serological inquiry for the detection of antibodies against the Human Immunodeficiency Virus (HIV) in children in a general ward

Osmo, André Alexandre; Honda, Janete; Baldacci, Evandro Roberto; Okay, Yassuhiko; Manissadjian, Antranik
Fonte: Universidade de São Paulo. Faculdade de Saúde Pública Publicador: Universidade de São Paulo. Faculdade de Saúde Pública
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/04/1990 POR
Relevância na Pesquisa
46.1%
São apresentados os resultados de um inquérito sorológico para a detecção de anticorpos contra o Vírus da Imunodeficiência Humana (VIH), em grupo não selecionado de crianças, internadas numa enfermaria geral de pediatria. Foram testados 441 pacientes pelo método ELISA, com uma positividade de 1,1 %, cujos resultados foram confirmados pelos testes de Western-Blot e/ou ImunoBlot. Nenhum dos cinco pacientes com teste positivo apresentou história de transfusão anterior, enquanto que 4,3% dos pacientes estudados apresentaram história transfusional. Todas as mães apresentaram também testes ELISA positivos. Em quatro casos, pelo menos um dos genitores referiu uso de drogas por via endovenosa. Em todas as crianças, o modo de transmissão foi vertical. A partir desses achados sugere-se a necessidade de a equipe de saúde tomar precauções quando da manipulação de sangue ou secreções. Recomenda-se a realização de inquéritos anônimos em enfermarias de hospitais gerais para auxiliar na determinação da real prevalência das infecções pelo VIH.; The results of a serum inquiry for detection of antibodies against the Human Immunodeficiency Virus in a non selected group of children, patients of a general pediatric ward...

Avaliação de testes sorológicos para a detecção de anticorpos anti-HIV em painéis de soros de brasileiros; Evaluation of enzyme-linked immunosorbent and alternative assays for detection of HIV antibodies using panels of Brasilian sera

Ivo-Dos-Santos, Jairo; Mello, Deise L. Campos; Couto-Fernandez, José C.; Passos, Roberto M.; Dias-Carneiro, Leila A.; Castilho, Euclides A.; Galvão-Castro, Bernardo
Fonte: Universidade de São Paulo. Instituto de Medicina Tropical de São Paulo Publicador: Universidade de São Paulo. Instituto de Medicina Tropical de São Paulo
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/04/1990 ENG
Relevância na Pesquisa
56.08%
Os soros de 472 brasileiros, confirmados como sendo positivos ou negativos em relação à presença de anticorpos anti-HIV e compreendendo todo o espectro clínico da infecção, foram utilizados na avaliação de seis ensaios imunoenzimáticos comerciais (ELISA), bem como de quatro testes alternativos tais como imunofluorescência indireta (IFI), hemaglutinação passiva (HP), dot blot e Karpas AIDS cell test. As sensibilidades variaram de 100% (ELISA Abbott e Roche) a 84,2% (HP) e as especificidades variaram de 99,3% (IFI) a 80,2% (HP). A sensibilidade e especificidade da HP e a sensibilidade do Karpas AIDS cell test foram significativamente menores que os outros ensaios. Embora a IFI e o dot blot tivessem apresentado uma boa sensibilidade e especificidade, os ensaios imunoenzimáticos (ELISA) foram mais adequados para serem utilizados em triagem quando outros parâmetros tais como facilidade de leitura e interpretação dos resultados e duração dos ensaios foram considerados.; Sera from 472 Brazilian subjects, confirmed to be either positive or negative for HIV antibodies and comprising the total clinical spectrum of HIV infection, were utilized in the evaluation of six commercially available enzyme-linked immunosorbent assays (ELISA)...

Soropositividade para HIV em doentes de herpes zoster; Seropositivity for HIV among zoster patients

Vasconcellos, Mônica R. A.; Castro, Luiz G. M.; Santos, Maurici F. dos
Fonte: Universidade de São Paulo. Instituto de Medicina Tropical de São Paulo Publicador: Universidade de São Paulo. Instituto de Medicina Tropical de São Paulo
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; ; Formato: application/pdf
Publicado em 01/10/1990 POR
Relevância na Pesquisa
46.22%
Os autores estudam a relação de zoster com soropositividade para HIV. Foram testados soros de 66 pacientes (31 homens e 35 mulheres) com quadro agudo de zoster, usando-se o método de ELISA para detectar anticorpos anti-HIV. Não houve seleção dos pacientes, evitando assim lidar com amostra viciada. Entre os 7 HIV +, 6 pertenciam a grupo de risco para AIDS, todos eram do sexo masculino e seis tinham idade entre 19 e 39 anos (idade média de 31,7 anos). Os resultados sugerem que o diagnóstico de herpes zoster em pacientes jovens não se vincule necessariamente à infecção pelo HIV. Quando, no entanto, o doente pertence a grupo de risco para AIDS, independentemente de sua idade, existe associação estatisticamente significativa, tornando-se imperativa a pesquisa de anticorpos anti-HIV.; Relationship between zoster and seropositivity for HIV is studied. Serum samples from 66 patients presenting acute zoster infection were tested for HIV antibodies, using ELISA. There was no previous selection of patients, what rendered the population studied unbiased. Seven patients (10.6%) were positive for HIV antibodies. Among them six belonged to AIDS risk groups, all were males and six had ages between 19 and 39 years (mean age value 31.7). Results suggest that the finding of zoster in younger age groups is not necessarily linked to HIV infection. When zoster is diagnosed in patients who belong to AIDS risk groups...