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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Genotipagem da gp41 do Vírus da Imunodeficiência Humana tipo 1 (HIV-1) em indivíduos respondedores e não respondedores ao inibidor de fusão T20 / Genotyping of gp41 of the Human Immunodeficiency Virus Type 1 (HIV-1) from non-responders and responders patients receiving T20 treatment

Azevedo, Rafael Gonçalves de [UNIFESP] 28 October 2009 (has links) (PDF)
Made available in DSpace on 2015-07-22T20:50:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-10-28. Added 1 bitstream(s) on 2015-08-11T03:25:28Z : No. of bitstreams: 1 Publico-00284.pdf: 1210351 bytes, checksum: 9468c9b00f4f6d4853d0e556a03096c4 (MD5) / Introdução: a falha ao HAART torna importante o desenvolvimento de novos fármacos que alvejam diferentes passos do ciclo de vida do HIV-1. O Enfuvirtide (T20) é um peptídeo sintético que mimetiza a região HR2 da gp41 do HIV-1, impedindo sua fusão e entrada na célula hospedeira. A presença de mutações de resistência primária ao T20 pode levar a falta de resposta virológica sustentada (RVS) em indivíduos em falha terapêutica ao HAART. Objetivos: genotipar a gp41 do HIV-1 de indivíduos considerados respondedores e não respondedores ao T20; verificar se a presença de mutações de resistência primária poderia interferir na RVS; correlacionar o status RVS com aspectos virais, imunológicos e tropismo. Metodologia: DNA genômico do baseline (antes do tratamento), 6 e 12 meses após o tratamento com T20, foi purificado utilizando QIAamp DNA Mini kit (Qiagen®, Valencia, Califórnia, USA). Todos pacientes receberam terapia otimizada mais T20 no inicio. 506 pb referentes as regiões HR1 e HR2 da gp41 foram amplificados por PCR “nested”. A PCR “nested” da região V3 para estudo do tropismo viral amplificou 654 pb. A PCR foi purificada utilizando Montage® PCR Centrifugal Filter Devises (Millipore®). As PCRs purificadas das regiões V3 e gp41 foram sequenciadas no ABI Prism 3130 Genetic Analyser (Applied Biosystems, Ca, USA) com o kit comercial BigDye® Terminator Cycle Sequencing versão 3.1 (Applied Biossystems, Foster City. Califórnia, USA). Iniciadores da segunda etapa da PCR “nested” foram utilizados para sequenciar. Resultados: sete indivíduos apresentavam um perfil de resposta ao T20 por 12 meses, 4 por pelo menos 6 meses e dois não responderam entre 6 e 12 meses. A média de idade foi de 44,92 ± 5,39, sendo 46,16% do sexo feminino e 53,84% do masculino. Dos 13 pacientes analisados, 12 pertencem ao subtipo B e 1 ao F1. Oito pacientes apresentaram o correceptor R5 e cinco o X4. Não foram encontradas mutações nas posições 36 a 45 da HR1 em 12 meses. Tivemos a N42S, que é responsável pela diminuição da susceptibilidade ao T20. De um total de 59 aminoácidos analisados na HR1, observamos 18,64% de trocas e na região HR2, 38,88%. Na HR1 no período de 8 meses ou mais em relação ao baseline, não encontramos modificações nas posições 36 a 45. De um total de 59 aminoácidos analisados, observamos 15,25% de trocas e na HR2, 36,11%. Verificamos a E137K sem a presença da N43D, que causou resistência. Verificamos a S138T como mutação de primaria com persistência de 12 meses sem a N43D e a falta de resposta ao tratamento. Na contagem de T CD4+, não encontramos diferença estatística entre as médias dos diferentes grupos (ANOVA – p=0,1). As cargas virais após 6 meses foram indetectáveis (<50 copias/mL) em 69,23% dos pacientes. Houve queda de carga viral do baseline para 6 meses (p=0.034), assim como para 6 meses e 8 meses ou mais. O uso do medicamento teve interferência significativa quando comparados o baseline e 6 meses (p=0.004) e entre o baseline e 12 meses (p=0.022), mas entre 6 e 12 meses a interferência não foi significativa, mostrando que após 6 meses ela permanece sustentada. Entre as variáveis, indivíduos respondedores e genótipo R5 houve alto valor de similaridade (76.98). Ocorreu agrupamento entre as duas amostras dos respondedores com genótipo X4 com as mutações 306, 311 e 320, que o caracterizam. Discussão: em relação ao tropismo, 38,47% dos pacientes que estudamos apresentaram correceptor X4 após alguns anos de infecção e múltiplos esquemas HAART. Este resultado mostra concordância com a literatura, que descreve uma taxa média de 50%. A N42S, observada em nosso estudo é relacionada com diminuição da susceptibilidade da droga. Apesar disso, somente um dos pacientes não respondeu ao tratamento, não obtendo ganho imunológico. Conclusão: o tropismo dos vírus HIV-1 na maioria dos indivíduos que responderam ao T20 está fortemente associado com o R5, que não causa progressão rápida. A presença da S138T foi suficiente para a falta de resposta ao T20, sem associação com a N43D. Mostramos evidente RVS e recuperação imunológica com o T20, mas que não foi suficiente para retirar estes indivíduos do risco de doenças oportunistas. Nosso estudo evidenciou a importância de iniciar o resgate quando a contagem de linfócitos T CD4+ está acima de 200 células/mm3. / Introduction: the failure to HAART becomes important to development of new drugs that target different steps of the life cycle of HIV-1. The Enfuvirtide (T20) is a synthetic peptide that mimics the HR2 region of gp41 of HIV-1, preventing its fusion and entry into the host cell. The presence of primary resistance mutations to T20 can lead to lack of sustained virologic response (SVR) in people in the HAART failure. Objectives: to genotype the gp41 of HIV-1 subjects considered responders and nonresponders to T20; verify the presence of primary resistance mutations could influence the SVR, SVR status correlate with aspects of viral, immunological and tropism. Methodology: genomic DNA from baseline (before treatment), 6 and 12 months after treatment with T20, was purified using QIAamp DNA Mini kit (Qiagen ®, Valencia, California, USA). All patients received optimal therapy more T20 at the beginning. 506 bp referring to the HR1 and HR2 regions of gp41 were amplified by PCR nested. PCR nested the V3 region to study viral tropism amplified 654 bp. The PCR was purified using Montage ® PCR Centrifugal Filter Devises (Millipore ®). The PCRs of purified V3 and gp41 regions were sequenced in ABI Prism 3130 Genetic Analyzer (Applied Biosystems, CA, USA) with commercial kit BigDye ® Terminator Cycle Sequencing version 3.1 (Applied Biossystems, Foster City. California, USA). Initiators of the second stage of PCR nested were used for sequencing. Results: seven patients had a higher response to T20 for 12 months, 4 for at least 6 months and two did not respond between 6 and 12 months. The average age was 44.92 ± 5.39, and 46.16% female and 53.84% male. Of the 13 patients analyzed, 12 belong to subtype B and 1 to F1. Eight patients had the coreceptor R5 and five the X4. There were no mutations at positions 36 to 45 of HR1 in 12 months. We acquired the N42S, which is responsible for decreased susceptibility to T20. From a total of 59 amino acids analyzed in HR1, we observed 18.64% of change and in HR2 region, 38.88%. In HR1 within 8 months or more compared to the baseline, we found no changes in positions 36 to 45. From a total of 59 amino acids analyzed, we observed 15.25% of change and in HR2, 36.11%. We checked the E137K without the presence of N43D, which caused resistance. We checked the S138T mutation as the primary persistence of 12 months without the N43D and the lack of response to treatment. On the count of CD4 + T cells, we found no statistical difference between the means of different groups (ANOVA - p = 0.1). The viral loads after 6 months were undetectable (<50 copies / mL) in 69.23% of patients. There was a decrease in viral load baseline to 6 months (p = 0.034) and for 6 months and 8 months or more. The use of the drug had significant interference when compared to baseline and 6 months (p = 0.004) and between baseline and 12 months (p = 0.022), but between 6 and 12 months the interference was not significant, showing that after 6 months it remains sustainable. Among the variables, responders and R5 genotype, there were high value of similarity (76.98). There was a grouping between the two samples of responders with X4 genotype with mutations 306, 311 and 320 which characterize it. Discussion: regarding tropism, 38.47% of the patients studied had correceptor X4 after a few years of infection and multiple HAART regimens. This result shows agreement with the literature, which describes an average rate of 50%. The N42S, observed in our study is associated with decreased drug susceptibility. However, only one patient did not respond to treatment, without increase of his immune. Conclusion: the tropism of HIV-1 in the majority of people who responded to the T20 is strongly associated with the R5, which causes rapid progression. The presence of S138T was sufficient for the lack of response to T20, but no association with N43D. It was clearly shown SVR and immune recovery with the T20, but that was not enough to remove these people from the risk of contracting opportunistic diseases. Our study showed the importance of starting the rescue when the count of CD4 + T cells are above 200 cells/mm3. / TEDE / BV UNIFESP: Teses e dissertações
2

Contribution à l'expérience G(^O) de violation de la parité : calcul et simulation des corrections radiatives et étude du bruit de fond

Guler, Hayg 17 December 2003 (has links) (PDF)
AUCUN
3

Akustik och elevers uppfattningav ljudmiljön i klassrum : En undersökning av akustiken på gymnasieskolan NTI / Acoustics and students perception of sound environment in classrooms

Benson, Alexis January 2018 (has links)
Klassrumsakustik behandlar rumsliga förutsättningar för ljudutbredning där god talhörbarhet är av vikt för elevers och lärares välbefinnande och möjligheter till goda lärmiljöer. Även kognitiva förmågor som minnesfunktioner påverkas av ljudmiljöer, där lägre bakgrundsljudnivåer och kortare efterklangstider förordas av forskning och byggnadstekniska standarder. Bakgrundsljudnivåer, efterklangstider T20 och reflexnivåer C50 kan tillsammans ge en bild av en god ljudmiljö för lärande i klassrum. I denna undersökning har fem klassrums ljudmiljöer utvärderats och enkätundersökningar har använts för att undersöka elevers och lärares subjektiva upplevelser av dessa ljudmiljöer under aktuella lektionstillfällen. Det har inte kunnat dras några tydliga korrelationssamband mellan akustiska data och subjektiva upplevelser av ljudmiljön från denna undersökning. Dock har undersökningen erhållit akustiska mätvärden från de aktuella klassrummen och speciellt två av klassrummen har funnits undermåliga i jämförelse med riktvärden från standarder med avseende på efterklangstider. / Classroom acoustics deal with spatial prerequisites for sound propagation, where good speech audibility is important for the well-being of students and teachers and provide opportunities for good learning environments. Cognitive abilities as memory functions are also influenced by sound environments, where lower background noise levels and shorter reverberation times are advocated by research and acoustical performance criteria for classrooms. Background noise levels, reverberation time T20 and room response C50 can together provide a picture of a good sound environment for classroom learning. In this survey, five classroom sound environments have been evaluated and questionnaires have been used to investigate the subjective experiences of pupils and teachers in these sound environments during current investigated lessons. There has been no clear correlation between acoustic data and subjective experiences of the audio environment from this survey. However, the survey has obtained acoustic measurements from the current classrooms and especially two of the classrooms have been found to be substandard in comparison with the guideline values of reverberation time from standards.
4

Contribution à l'expérience $G^0$ de violation de la parité : calcul et simulation des corrections radiatives et étude du bruit de fond

Guler, Hayg 17 December 2003 (has links) (PDF)
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5

Caractérisation des interactions d'inhibiteurs de l'entrée du VIH dans un modèle de cellules dendritiques in vitro

Bélanger-Jasmin, Geneviève January 2003 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
6

The Tensor Analyzing Power T20 in Deuteron Break-up Reactions within the Bethe-Salpeter Formalism

Kaptari, L. P., Umnikov, A. Y., Kämpfer, B., Khanna, F. C. 26 August 2010 (has links) (PDF)
The tenser analyzing power T-20 and the polarization transfer kappa in the deuteron break-up reaction Dp --> pX are calculated within a relativistic approach based on the Bethe-Salpeter equation with a realistic meson-exchange potential. Our results on T-20, kappa and the cross section are compared with experimental data and non-relativistic calculations and with the outcome of a relativization procedure of the deuteron wave function.
7

The Tensor Analyzing Power T20 in Deuteron Break-up Reactions within the Bethe-Salpeter Formalism

Kaptari, L. P., Umnikov, A. Y., Kämpfer, B., Khanna, F. C. January 1994 (has links)
The tenser analyzing power T-20 and the polarization transfer kappa in the deuteron break-up reaction Dp --> pX are calculated within a relativistic approach based on the Bethe-Salpeter equation with a realistic meson-exchange potential. Our results on T-20, kappa and the cross section are compared with experimental data and non-relativistic calculations and with the outcome of a relativization procedure of the deuteron wave function.

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