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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.
151

Estudo da expressão de citocinas e componentes de apoptose no tumor de Walker 256, comparação entre a linhagem A e variant Ar / Study of cytokine gene expression and components of apoptosis in Walker 256, a comparison of variants A (Aggressive) and AR (Regressive)

Perroud, Ana Paula de Almeida Salles 18 October 2005 (has links)
Orientador: Ricardo de Lima Zollner / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-09T02:29:32Z (GMT). No. of bitstreams: 1 Perroud_AnaPauladeAlmeidaSalles_M.pdf: 4222371 bytes, checksum: 5ff171cf192f89e5602e731098f85f66 (MD5) Previous issue date: 2005 / Resumo: Duas variantes do Walker 256 foram descritas como Walker 256 A e AR. A variante A é mais agressiva e pode induzir os efeitos sistêmicos como anorexia, retenção de sódio, líguido de perda de peso e morte. Os mecanismos envolvidos na regressão e progressão tumoral são desconhecidos. No presente trabalho, células esplênicas e tumorais de animais inoculados com variantes A e Ar foram isoladas para avaliar a expressão gênica de TGF-ß, IL-12, TNF-a e IFN-? e componentes de apoptose relacionando com anemia, perda de peso, peso do baço, peso do tumor e fragilidade osmótica comparando controles inoculados com Ringer Lactato. Os resultados mostraram que o grupo inoculado com a variante A comparado com a variante Ar, apresenta altos níveis de expressão de TGF-ß em ambas as células esplênicas e tumorais, ausência de expressão de IFN-? e aumento progressivo dos níveis de IL-12 sem infiltrado inflamatório. Esses resultados sugerem que a agressividade da variante A está relacionada á modulação de citocinas, facilitando o crescimento e escape tumoral. A IL-12 pode ser constitutiva nas linhagens A e Ar. A expressão gênica de Bcl-2 foi progressiva e não houve expressão de Fas nas células tumorais do grupo A. Estes resultados demonstram que na linhagem A a imumogenicidade ocorre por outros mecanismos. A expressão de citocinas e componentes de apoptose pode explicar as diferenças das linhagens A e Ar / Abstract: Two variants of this Walker 256 tumor have been previously reported as Walker 256 A and variant Ar. The variant A is more aggressive and can induce systemic effects as anorexia, sodium and water retention, followed by weight loss and death. The mechanisms involved in enhancing tumor regression and progression in this model is still incompletely understood. In the present study, spleen cells and tumor cells from animals inoculated with variants A and AR, were isolated to investigate the TGF-ß, IL-12, IFN-?, TNF-a gene expression, components of apoptosis and relationship with anemia, weight of animals, weight of spleen, height of tumor and osmotic fragility compared with controls inoculated with Ringer Lactate. Results demonstrate that the group inoculated with variant A compared with variant Ar, shows high levels of TGF-ß gene expression in both tumor tissue and spleen cells, no expression of IFN-? and a progressive and higher levels of IL-12 in tumor tissue without inflammatory infiltrate. These results suggest that the aggressively of variant A is relate to cytokine modulation, facilitating the growth and escape of tumor cells. Furthermore, IL-12 seems to be constitutively expressed in both tumor lineage A and AR. The mRNA expression of Bcl-2 was progressive and there is no expression of Fas on tumoral cells of group A. These results demonstrate that on the lineage A the immunogenicity occurs by others mechanisms. The expression of cytokines and components of apoptosis can explain the differences of lineages A and AR / Mestrado / Clinica Medica / Mestre em Clinica Medica
152

Avaliação do efeito da matriz derivada do esmalte (Emdogain®) sobre o processo de cicatrização de feridas cutâneas cirúrgicas em ratos Wistar

Côrtes, Andréa Junqueira 14 July 2014 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-02-12T10:02:46Z No. of bitstreams: 1 andreajunqueiracortes.pdf: 11746820 bytes, checksum: cd7019a0ace25082404e47c8d3645bc8 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-02-26T12:06:29Z (GMT) No. of bitstreams: 1 andreajunqueiracortes.pdf: 11746820 bytes, checksum: cd7019a0ace25082404e47c8d3645bc8 (MD5) / Made available in DSpace on 2016-02-26T12:06:29Z (GMT). No. of bitstreams: 1 andreajunqueiracortes.pdf: 11746820 bytes, checksum: cd7019a0ace25082404e47c8d3645bc8 (MD5) Previous issue date: 2014-07-14 / A matriz derivada do esmalte (EMD) é um complexo proteico de origem ectodérmica, isolado de germes dentários em desenvolvimento. Originalmente utilizada na regeneração de tecidos do periodonto, vem se mostrando um excelente recurso na regeneração de outros tecidos mesenquimais como derme, tecido ósseo e tendão. No presente estudo, o potencial cicatrizante da matriz foi analisado histopatologicamente em feridas cutâneas cirúrgicas realizadas em ratos Wistar, eutanaziados nos dias 01, 03, 07, 14 e 21. Durante o experimento, as feridas foram acompanhadas macroscopicamente e, a seu término, foram removidas e submetidas ao processamento histológico. À avaliação microscópica, foi observado que as lesões tratadas com a EMD evoluíram para o remodelamento dérmico de modo mais eficaz em tempo e qualidade em relação ao grupo controle não tratado, a partir do 3º dia pós-operatório; o amadurecimento e organização do colágeno foi bastante evidente a partir do 7º dia e, destaca-se que nos dias 14 e 21 o plano muscular, na profundidade da pele, exibiu excelente regeneração, sendo que, também neste período, o amadurecimento vascular se mostrou mais significativa nas amostras tratadas. Além da análise histomorfométrica, foi realizada a avaliação da expressão de iNOS, TGF- β2 e TNF-α por imunoistoquímica. A expressão de iNOS foi significativamente mais expressiva nas amostras tratadas, aumentando progressivamente a partir do 7º dia pós-operatório. Os resultados sugerem que a EMD, aplicada em feridas cutâneas cirúrgicas, potencializa a neoformação e o remodelamento de colágeno, amadurecimento vascular e regeneração muscular possivelmente via modulação do óxido nítrico. / The enamel matrix derivative (EMD) is a protein complex of ectodermal origin, isolated from the developing tooth germs. Originally used in the regeneration of periodontal tissues, has proved to be an excellent resource in the regeneration of other mesenchymal tissues such as dermis, bone and tendon. In the present study, the healing potential of the matrix was analyzed histologically in surgical wounds made in Wistar rats, euthanized on days 01, 03, 07, 14 and 21. During the experiment, the wounds were followed macroscopically, and at its end, were removed and subjected to histological processing. For microscopic evaluation, it was observed that the lesions treated with EMD progressed to dermal remodeling more effectively in time and quality in relation to the untreated control group, from the 3th postoperative day ; the maturation and organization of the collagen was quite evident from the 7th day , and it is noteworthy that on 14 and 21 muscle -up, the skin depth, showed excellent regeneration, and also in this period, vascular maturation showed more significantly in the treated samples. In histomorphometric analysis, evaluation of iNOS, TGF- β2, and TNF-α expression was performed by immunohistochemistry. The expression of iNOS was significantly more expressive in the treated samples, increasing progressively from the 7th postoperative day. The results suggest that EMD applied on surgical wounds enhances the new formation and remodeling of collagen, vascular maturation and muscle regeneration possibly via modulation of nitric oxide.
153

Imunogenicidade e segurança da vacina contra influenza A H1N1/2009 em pacientes com doenças reumáticas em uso de terapia anti-TNF alfa / Immunogenicity and safety of influenza A H1N1/2009 vaccine in rheumatic diseases patients under anti-TNF therapy

Ivan Leonardo Avelino França e Silva 05 December 2014 (has links)
\\OBJETIVOS: Avaliar a imunogenicidade e a segurança a curto prazo da vacina H1N1 pandêmica em pacientes com artrite reumatóide (AR) e espondiloartrites [ESa - artrite psoriática (AP) e espondilite anquilosante (EA)] recebendo classes distintas de terapia anti-TNF, assim como comparação com pacientes que receberam drogas modificadoras de doenças reumáticas (DMARDs) e controles saudáveis. MÉTODOS: Cento e vinte pacientes (AR, n=41; EA, n=57 e artrite psoriática - AP, n=22) em uso de agentes anti-TNF (monoclonal, n=94 e receptor solúvel, n=26) foram comparados com 116 pacientes com artrite inflamatórias em uso de DMARDs e 117 controles saudáveis. Soroproteção (SP), soroconversão (SC), médias geométricas dos títulos (MGTs), fator de aumento (FI) das MGT e eventos adversos foram avaliados 21 dias após a vacinação. RESULTADOS: Após a imunização, as taxas de SC (58,2% vs 74,3%, p=0,017) foram significativamente menores nos pacientes com espondiloartrites que receberam a terapia anti-TNF, enquanto nenhuma diferença foi observada em pacientes com AR que recebem esta terapia, em comparação com controles saudáveis (p=0,067). Pacientes com espondiloartrites que receberam anticorpos monoclonais (infliximabe/adalimumabe) tiveram uma taxa de SC significativamente menor em comparação com controles saudáveis (51,6% vs. 74,3%, p=0,002) ou para aqueles em uso de DMARDs (51,6% vs. 74,7%, p=0,005), por sua vez não houve diferença para pacientes em uso de etanercepte (86,7% vs. 74,3%, p=0,091). Uma análise dos pacientes com espondiloartrites que apresentaram SC e os que não apresentaram SC revelou que o primeiro grupo teve maior média de idade (p=0,003), maior frequência de anti-TNF (p=0,031) e anticorpos monoclonais (p=0,001), e uma menor frequência de metotrexate (p=0,028). Na regressão logística multivariada, apenas a idade avançada (p=0,015) e tratamento anticorpos monoclonais (p=0,023) permaneceram fatores importantes para a não SC em pacientes com espondiloartrites. CONCLUSÕES: Este estudo mostrou um padrão distinto da resposta imune à vacina contra a gripe pandêmica em pacientes com artrite inflamatória que receberam agentes anti-TNF, com uma imunogenicidade reduzida apenas em pacientes com espondiloartrites usando anticorpos monoclonais / OBJECTIVES: To evaluate the immunogenicity of the anti-influenza A H1N1/2009 vaccine in rheumatoid arthritis (RA) and spondyloarthritis patients receiving distinct classes of anti-TNF agents compared with patients receiving DMARDs and healthy controls. METHODS: One hundred and twenty patients (RA, n=41; ankylosing spondylitis - AS, n=57 and psoriatic arthritis - PsA, n=22) under anti-TNF agents (monoclonal, n=94 and soluble receptor, n=26) were compared to 116 inflammatory arthritis patients under DMARDs and 117 healthy controls. Seroprotection (SP), seroconversion (SC), geometric mean titre (GMT), factor increase (FI) in GMT and adverse events were evaluated 21 days after vaccination. RESULTS: After immunisation, SC rates (58.2% vs. 74.3%, p=0.017) were significantly lower in spondyloarthritis patients receiving anti-TNF therapy, whereas no difference was observed in RA patients receiving this therapy compared to healthy controls (p=0.067). Spondyloarthritis patients receiving monoclonal antibodies (infliximab/adalimumab) had a significantly lower seroconversion rate compared to healthy controls (51.6% vs. 74.3%, p=0.002) or to those under DMARDs (51.6% vs. 74.7%, p=0.005), whereas no difference was observed for patients under etanercept (86.7% vs. 74.3%, p=0.091). Further analysis of non-seroconverting and seronconverting spondyloarthritis patients revealed that the former group had a higher mean age (p=0.003), a higher frequency of anti-TNF (p=0.031) and monoclonal antibodies (p=0.001), and a lower frequency of methotrexate (p=0.028). In multivariate logistic regression, only older age (p=0.015) and monoclonal antibodies treatment (p=0.023) remained significant factors for nonseroconversion in spondyloarthritis patients. CONCLUSIONS: This study revealed a distinct disease pattern of immune response to the pandemic influenza vaccine in inflammatory arthritis patients receiving anti-TNF agents, illustrated by a reduced immunogenicity solely in spondyloarthritis patients using monoclonal antibodies
154

Avaliação dos parâmetros clínicos da superfície ocular e da citologia de impressão conjuntival nos pacientes com olho seco associado a doença reumatológica submetidos a tratamento com terapia anti-TNF / Evaluation of ocular surface clinical parameters and conjunctival impression cytology of rheumatic disease associated dry eye patients submitted to anti-TNF therapy

Fany Solange Usuba 12 December 2017 (has links)
OBJETIVOS: Avaliar as alterações clínicas da superfície ocular, citologia de impressão (CI) e sintomas de olho seco (OS) dos pacientes com Espondilite Anquilosante (EA) e Artrite Reumatoide (AR). Classificar a intensidade de OS. Avaliar prospectivamente os parâmetros clínicos, laboratoriais e da superfície ocular dos pacientes com EA e AR submetidos a tratamento com drogas anti-TNF. MÉTODOS: Estudo prospectivo envolvendo inicialmente (pré-tratamento) 36 pacientes com EA e 20 pacientes com AR comparados com grupo controle de 39 voluntários saudáveis para o grupo de EA e 24 voluntários saudáveis para o grupo de AR. Do total inicial, 14 pacientes consecutivos com EA e 20 pacientes consecutivos com AR foram submetidos a terapia anti-TNF. Foram realizados os seguintes exames: teste de Schirmer I, tempo de rompimento do filme lacrimal, tingimento com corantes vitais e questionário dos sintomas de OS (Ocular Surface Disease Index-OSDI), citologia de impressão (CI) conjuntival, avaliação laboratorial inflamatória: velocidade de hemossedimentação e proteína C reativa (VHS e PCR) e atividade da doença pelas medidas de Bath Ankylosing Spondylitis Activity Index e Bath Ankylosing Spondylitis Functional Index (BASDAI e BASFI respectivamente) na EA e Disease Activity Score 28 (DAS 28) para AR. Além disso, avaliou-se a qualidade de vida pelo Health Assessment Questionnaire (HAQ) para ambas as doenças. As avaliações foram realizadas pré-tratamento e repetidas aos 3 meses (3M) e 12 meses (12M) após o início da terapia. RESULTADOS: Na avaliação pré-tratamento com drogas anti-TNF, os pacientes com EA apresentaram OS de intensidade leve a moderada (80,5% versus 43,6%, p=0,01) e maior escore de alteração da CI (55% versus 12,8%, p=0,007) associados a provas de atividade inflamatórias elevadas (p < 0,001) quando comparados com controles saudáveis. A avaliação longitudinal do tratamento com terapia anti-TNF demonstrou melhora da produção aquosa lacrimal (pré-tratamento: 13,7 ? 11,3 mm, aos 3M: 18,3 +- 11,1 mm e aos 12M: 19,3 +- 9,0 mm, p=0,04) assim como da CI conjuntival (pré-tratamento: 78,6% alterada, aos 3M: 57,1%, e aos 12M: 35,7%, p=0,03). Houve, paralelamente, melhora dos parâmetros inflamatórios e da atividade da doença (p < 0,05). No grupo de pacientes com AR, no momento pré-tratamento com drogas anti-TNF, foram observados maior frequência (75% versus 4%, p < 0,001) e intensidade leve de OS (65% versus 4%, p < 0,001) associados a sintomas moderados (escore OSDI 24,0 +- 17,6 versus 7,5 +- 14,3, p=0,001) quando comparados com controles saudáveis. Esses pacientes também apresentaram maior frequência de disfunção das glândulas de meibômio (55,0% versus 8,3%, p=0,001), maior escore de alteração da CI conjuntival (1,0 +- 0,6 versus 0.0 +- 0,2, p=0,001) e menor densidade de células caliciformes (431,3 +- 209,5 células/mm2 versus 804,8 +- 383,2 células/mm2, p < 0,001) quando comparados com o grupo controle. A análise prospectiva dos pacientes com AR tratados com drogas anti-TNF mostrou um aumento dos valores do teste de Schirmer (prétratamento: 11,8 +- 6,7 mm, aos 3M: 21,0 +- 10,4 mm, e aos 12M: 23,0 +- 9,7mm, p < 0,001), melhora da CI conjuntival (pré-tratamento: 1,0 +- 0,6, aos 3M: 0,8 +- 0,6, e aos 12M: 0,5 +- 0,5, p=0,005) e da densidade de células caliciformes (pré-tratamento: 429 +- 211,7 células/mm2, aos 3M: 908 +- 291,4 células/mm2, e aos 12M: 1265,4 +- 430,6 células/mm2, p=0,001). Os marcadores de atividade inflamatória sistêmicos (VHS e PCR) também melhoraram ao longo do tratamento (p=0,005 e p=0,006, respectivamente). CONCLUSÃO: Os pacientes com EA e AR avaliados nesse estudo apresentaram prevalência elevada de OS de intensidade leve a moderada associada à alteração da citologia conjuntival. A recuperação precoce e manutenção de longo prazo na produção aquosa da lágrima e na CI conjuntival, em especial, das células caliciformes, nos pacientes submetidos a terapia anti-TNF, pode refletir a melhora da condição inflamatória. Esse resultado histológico pode ter influência como biomarcador da inflamação na superfície ocular / OBJECTIVES: Evaluate ocular surface parameters, impression cytology (IC) and dry eye (DE) symptoms of patients with Ankylosing Spondylitis (AS) and Rheumatoid Arthritis (RA). Classify DE severity grade. Analyse prospectively clinical and laboratory, as well as ocular surface parameters of AS and RA patients, submitted to anti-TNF therapy. METHODS: This prospective study initially (baseline) enrolled 36 AS patients and 20 RA patients who were compared to a control group of 39 and 24 healthy volunteers for the AS group and RA group, respectively. From the initial group, 14 consecutive AS and 20 consecutive RA patients received anti-TNF therapy. They underwent the following exams: Schirmer I test, tear break-up time, vital dyes staining of the ocular surface, a questionnaire for dry eye symptoms- Ocular Surface Disease Index (OSDI), and conjunctival IC. Laboratory tests for inflammatory activity were assessed by erythrocyte sedimentation rate and C- reactive protein (ESR and CRP). The Bath Ankylosing Spondylitis Activity Index and Bath Ankylosing Spondylitis Functional Index (BASDAI and BASFI, respectively) in AS and Disease Activity Score 28 (DAS 28) in RA analyzed disease activity parameters. Besides, the Health Assessment Questionnaire evaluated the quality of life in both group of diseases. These measurements were taken at baseline (BL) and repeated at 3 months and 12 months (3M and 12M, respectively) after the beginning of anti-TNF therapy. RESULTS: At the baseline moment, AS patients presented mild to moderate DE (80.5% vs 43.6%, p=0.01) and a higher score of altered IC (55% vs 12.8%, p=0.007) associated with the systemic inflammatory activity (ESR and CRP, p < 0.001) when compared to healthy volunteers. The longitudinal evaluation of anti- TNF treatment showed an improvement of aqueous tear production (BL: 13.7 +- 11.3 mm, 3M: 18.3 +- 11.1 mm and 12M: 19.3 +- 9,0 mm, p=0.04). The IC also improved (BL: 78.6% altered IC, 3M: 57.1% and 12M: 35.7%, p=0.03). There was a parallel amelioration of systemic inflammatory markers and disease activity (p < 0.05). Concerning the RA group of patients, at the baseline moment, there was a higher frequency of DE (75% vs 4%, p < 0.001) as well as mild DE severity grade (65% vs 4%, p < 0,001) associated with moderate symptoms of DE (OSDI score: 24.0 +- 17.6 vs 7.5 +- 14.3, p=0.001) when compared to healthy volunteers. This group of patients also presented higher frequency of meibomian gland dysfunction (55% vs 8.3%, p=0.001), a worse score of IC (1.0 +- 0.6 vs 0.0 ? 0.2, p=0.001) and lower goblet cells count (431.3 +- 209.5 cells/mm2 vs 804.8 +- 383.2 cells/mm2, p< 0.001) when compared to the control group. The prospective analysis of RA patients treated with anti-TNF drugs demonstrated an increase of Schirmer\'s test (BL: 11.8 +- 6.7, 3M: 21.0 +- 10.4, 12M: 23.0 +- 9.7, p < 0.001) and an improvement of cytological grade (BL: 1.0 +- 0.6, 3M: 0.8 +- 0.6, 12M: 0.5 +- 0.5, p=0.005) and goblet cells density (BL: 429,0 +- 211.7 cells/mm2, 3M: 908,0 +- 291.4 cells/mm2, 12M: 1265.4 +- 430.6 cells/mm2, p=0.001). The systemic inflammatory markers (ESR and CRP) also improved throughout the treatment period (p=0.005 and p=0.006, respectively). CONCLUSION: Patients with AS and RA enrolled in this study presented a higher prevalence of mild to moderate DE associated with altered IC. The prompt and maintained aqueous tear and conjunctival cytology recovery, especially the goblet cells, in patients submitted to anti-TNF therapy seem to represent the improvement of inflammatory condition. This histological outcome may have an influence as a biomarker of ocular surface inflammation
155

Efeito da inibição da produção de TNF-alfa por meio da administração de pentoxifilina na pancreatite aguda experimental / Effect of inhibition of TNF-alpha production by pentoxifylline administration in experimental acute pancreatitis

André Siqueira Matheus 20 September 2006 (has links)
Pancreatite aguda é uma das principais causas de síndrome da resposta inflamatória sistêmica (SRIS). Complicações sistêmicas são os principais fatores responsáveis pela ocorrência de falência de múltiplos órgãos e sistemas e morte durante a primeira etapa da doença. Os níveis de mediadores inflamatórios possuem uma relação com a gravidade da pancreatite. O TNF-alfa tem sido descrito como o agente iniciador da resposta inflamatória da pancreatite aguda. Estudos prévios usando a pentoxifilina para bloquear a produção de TNF-alfa têm demonstrado efeitos benéficos quando usada em modelos experimentais de sepse ou choque. A infecção pancreática é a mais grave complicação da pancreatite aguda com índices de mortalidade que podem chegar a 80%. Os mecanismos que determinam a ocorrência da infecção pancreática não são bem esclarecidos. Objetivo: Determinar o efeito da inibição da produção de TNF-alfa na pancreatite aguda com a administração de pentoxifilina. Métodos: Foi utilizado um modelo experimental de pancreatite aguda grave através da injeção intraductal de taurocolato de sódio a 2,5%. Cento e vinte e quatro ratos Wistar machos foram divididos em três grupos: Controle (animais submetidos ao procedimento cirúrgico sem a administração de taurocolato de sódio), Pancreatite (animais submetidos à indução da pancreatite aguda) e Pentoxifilina (animais submetidos à indução da pancreatite aguda seguida da administração intraperitoneal de 25 mg/Kg de pentoxifilina). Foi realizada a dosagem sérica das interleucinas 6 e 10 e TNF-alfa duas horas após a indução da pancreatite. Foram analisadas a ocorrência de translocação bacteriana e a incidência de infecção pancreática, através de culturas realizadas 24 horas após a indução da pancreatite aguda e a mortalidade global. A ocorrência de infecção pancreática foi considerada como positiva quando a concentração de bactérias expressa em UFC/g foi maior que 105. Resultados: Quando comparado ao grupo Pancreatite, o grupo Pentoxifilina apresentou redução significativa da lesão histológica pancreática, dos níveis de IL-6, IL-10 e TNF-alfa e da ocorrência de infecção pancreática (p < 0,05), tais alterações se associam a redução significativa da mortalidade no grupo Pentoxifilina. Conclusão: A inibição da produção de TNF-alfa através da administração de pentoxifilina foi capaz de reduzir o processo inflamatório local e sistêmico, reduzir a translocação bacteriana e infecção pancreática e melhorar a sobrevida com redução dos índices de mortalidade desta grave doença / Acute pancreatitis (AP) is considered one of the typical conditions causing systemic inflammatory response (SIRS). Systemic complications are the most important contributors to multiple organ failure and death during the first stages of severe acute pancreatitis. Levels of pro-inflammatory cytokines increase during the course of AP, and these levels appear to be correlated with the severity of pancreatic inflammation. TNF-alfa may be an initiator of inflammatory process in AP. Previous studies using pentoxifylline to block TNF-alfa production have showed beneficial effects in experimental models of sepsis and shock. The gut is a target organ of the SIRS causing gut barrier dysfunction allowing bacteria and toxin translocation. Bacterial translocation has been implicated in the development of multiple organ failure and is one of the major causes of pancreatic infection in patients with pancreatic necrosis. Aim: To determinate the effects of inhibition of TNF-? on the pancreatic and systemic inflammatory response, pancreatic infection, and mortality rate in necrotizing acute pancreatitis in rats. Methods: An experimental model of severe AP by injection of 0.5ml of 2.5% sodium taurocholate into the pancreatic duct was utilized. A hundred and twenty four male Wistar rats were divided in 3 groups: Sham (surgical procedure without AP induction), Pancreatitis (AP Induction), and Pentoxifylline (AP induction plus administration of 25 mg/kg pentoxifylline). Pancreatic inflammatory response was measured by histological studies and systemic inflammatory response was analyzed measuring the production of inflammatory cytokines (IL-6, IL-10, and TNF-alfa). Pancreatic infection was evaluated with bacterial cultures performed 24 h after the AP induction. The numbers of organisms were expressed as colony forming units (CFU) per gram. The occurrence of pancreatic infection was also analyzed and considered positive when the CFU/g was > 105. A parallel survival study was also performed. Results: Inhibition of TNF-alfa by pentoxifylline shows beneficial effects in this experimental model. The Pentoxifylline group had a statistically significant reduction of histological damage in the pancreas, inflammatory cytokines levels (IL-6, IL-10, and TNF-?), and occurrence of pancreatic infection (p < 0.05). These changes were associated with a significant reduction of mortality rate. Conclusions: Inhibition of TNF-alfa reduced local and systemic inflammatory response, reduced systemic complication as pancreatic infection, and decrease mortality rate in this model. Pentoxifylline may provide a useful therapy in the treatment of acute pancreatitis
156

Oxygen delivery and mitochondrial dysfunction as assessed by microdialysis during interventions in experimental sepsis

von Seth, Magnus January 2017 (has links)
Early administration of broad-spectrum antibiotics is the first goal in sepsis treatment. Besides from bacteriostatic/bactericidal effects, some antibiotics may also modify the host´s response to infection. The novel antibiotic tigecycline may exert such properties; however, this property has not been evaluated in large-animal trials. We compared tigecycline with doxycycline and placebo in relation to anti-inflammatory, circulatory and organ dysfunction effects in a sterile pig model of sepsis. Doxycycline, but not tigecycline, reduced the inflammatory response as manifested by tumor necrosis factor alpha levels in plasma. Tigecycline, however, had a stabilizing effect on the circulation not exerted by doxycycline or placebo. To achieve rapid restoration of the circulating blood volume - another major goal in sepsis treatment - fluid bolus administration of is some-times practiced. In addition to crystalloids, albumin-containing solutions are suggested. Yet, some animal-experimental data suggests that rapid bolus administration of albumin reduces albumin’s plasma-expanding effect. We compared a rapid intravenous bolus of radiolabeled albumin with a slow infusion in a sterile pig model of sepsis. Rapid bolus of administration did not reduce plasma levels of albumin following administration and did not increase the amount of albumin that left the circulation. Inadequate oxygen delivery (DO2) by the circulation to the tissues may cause increased plasma lactate, which is the most striking effect of sepsis on the metabolism. However, experimental data and clinical trials refute this link, instead, suggesting other mechanisms, including impaired oxygen extraction, mitochondrial dysfunction and accelerated aerobic glycolysis. We investigated the impact of DO2, oxygen consumption (VO2), hemodynamic parameters and inflammatory response on plasma lactate and organ dysfunction in two experimental sepsis models. In the most severe cases of shock, with DO2, there was an increase in plasma lactate, but without a decrease in VO2, invalidating the assumption that the increase in lactate is due to anaerobic metabolism. To identify critical steps in the sepsis-induced increase in lactate, we inhibited the major energy-producing step in the electron transport chain (ETC). The combination of sepsis and ETC inhibition led to a cellular energy crisis. This finding suggests that early sepsis induces a partial mitochondrial dysfunction.
157

Avaliação do metabolismo e atividade inflamatória nas diversas formas evolutivas da doença de Chagas: correlação com disfunção autonômica / Evaluation of metabolism and inflammatory activity in different forms of Chagas\' disease: correlation with autonomic dysfunction

João Marcos Bemfica Barbosa Ferreira 29 November 2013 (has links)
INTRODUÇÃO: A cardiopatia chagásica crônica (CCC) apresenta características específicas, tais como: disfunção autonômica e atividade inflamatória exacerbada. Esta fisiopatologia sugere que alguns parâmetros metabólicos podem estar alterados em pacientes chagásicos. O objetivo deste estudo foi avaliar os parâmetros metabólicos e inflamatórios nas diversas formas evolutivas de doença de Chagas e sua correlação com medidas de avaliação do Sistema Nervoso Autônomo (SNA). MÉTODOS: Foram avaliados 60 indivíduos divididos em 4 grupos (n=15): Grupo controle (GC), Grupo FI - forma indeterminada, Grupo ECG- cardiopatia chagásica com alteração eletrocardiográfica sem disfunção ventricular e Grupo IC - cardiopatia chagásica com disfunção ventricular e insuficiência cardíaca. Todos os grupos foram pareados de acordo com sexo, idade e índice de massa corporal. Os pacientes realizaram dosagens sanguíneas de insulina, leptina, adiponectina, interleucina-6 (IL- 6) e fator de necrose tumoral-alfa (TNF-alfa) pelo método de ELISA. O SNA foi avaliado através da variabilidade da frequência cardíaca no holter 24 horas e no teste de inclinação postural. Os valores de RMSSD, pNN50 e do componente alta frequência (AF) foram utilizados como estimativa da atividade parassimpática. Os valores do componente de baixa frequência (BF) estimaram a atividade simpática. A análise estatística foi feita utilizando-se a ANOVA ou teste de Kruskal-Wallis para a comparação entre os grupos, o coeficiente de Spearman para a análise das correlações e a regressão linear múltipla para a análise multivariada. RESULTADOS: A leptina e insulina não apresentaram diferenças significativas entre os grupos [Leptina: GC=3,42 (7,43); FI=3,03 (6,53); ECG=5,56 (6,2); IC=2,86 (2,67) ng/ml; p=0,626. Insulina: GC=3,41 (1,98); FI=4,31 (2,85); ECG=4,30 (3,06); IC=4,58 (2,88) ng/ml; p=0,901] A adiponectina apresentou níveis maiores nos grupos ECG e IC [GC=4766,5 (5529,5); FI= 4003,5 (2482,5); ECG= 8376,5 (8388,5); IC= 8798 (4188) ng/ml; p < 0,001]. IL-6 e TNF-alfa foram maiores no Grupo IC [IL-6: GC=1,85 (6,41); FI=1,58 (1,91); ECG=1,0 (1,57); IC= 31,44 (72,19) pg/ml; p=0,001. TNF-?: GC=22,57 (88,2); FI=19,31 (33,16); ECG=12,45 (3,07); IC=75,15 (278,57) pg/ml; p=0,04]. A insulina, leptina e TNF-alfa não apresentaram correlações significativas com medidas de avaliação do SNA. A adiponectina apresentou correlação positiva com o componente AF (r= 0,336; p= 0,009) e correlação negativa com o componente BF (r= -0,336; p= 0,009). A interleucina-6 apresentou correlação positiva com o componente AF (r= 0,419; p=0,004) e correlação negativa com o componente BF (r= -0,393; p= 0,007). Porém, na análise multivariada apenas a adiponectina apresentou correlação significativa com medidas de função do SNA. CONCLUSÃO: A adiponectina foi maior nos grupos ECG e IC. A IL-6 e o TNF-alfa foram maiores no grupo IC. O aumento dos níveis de adiponectina esteve associado a diminuição da atividade simpática e predomínio da atividade parassimpática. / BACKGROUND: Chagas disease (CD) has specific characteristics such as autonomic dysfunction and increased inflammatory activity. This pathophysiology suggests that metabolic parameters can be altered in patients with CD. The aim of this study was to evaluate the metabolic and inflammatory parameters in different forms of CD and their correlation with Autonomic Nervous System (ANS) measures. METHODS: We evaluated 60 subjects divided into 4 groups (n=15): control group (CG), group IF (indeterminate form); group ECG (ECG abnormalities and normal left ventricular function in echocardiogram) and HF group (heart failure with left ventricular dysfunction). All groups were matched for age, sex and body mass index. The patients underwent insulin, adiponectin, leptin, interleukin-6 (IL-6) and tumor necrosis factor-alfa (TNF-alfa) measurements by ELISA. The Autonomic Nervous System was assessed by heart rate variability in 24-hour Holter and tilt test. RMSSD, pNN50 and High Frequency (HF) component values were used to estimate parasympathetic activity and low frequency (LF) components were used to estimate sympathetic activity. Statistical analyses were performed using ANOVA or Kruskal- Wallis tests to compare groups. Spearman coefficient was used for correlation analysis and linear regression for multivariate analysis. RESULTS: No significant differences were observed in leptin and insulin levels between groups. [Leptin: CG=3.42 (7.43); IF=3.03 (6.53); ECG=5.56 (6.2); HF=2.86 (2.67) ng/ml; p=0.626. Insulin: CG=3.41 (1.98); IF=4.31 (2.85); ECG=4.30 (3.06); HF=4.58 (2.88) ng/ml; p=0.901]. Adiponectin was higher in ECG and HF groups. [CG=4766.5 .(5529.5); IF= 4003.5 (2482.5); ECG= 8376.5 (8388.5); HF= 8798 (4188) ng/ml; p < 0.001)]. IL-6 and TNF-alfa were higher in HF group. [IL-6: CG=1.85 (6.41); IF=1.58 (1.91); ECG=1.0 (1.57); HF= 31.44 (72.19) pg/ml; p=0.001. TNF-alfa: CG=22.57 (88.2); IF=19.31 (33.16); ECG=12.45 (3.07); HF=75.15 (278.57) pg/ml; p=0.04]. Insulin, leptin and TNF-alfa did not correlate with autonomic dysfunction. Adiponectin correlated positively with HF component (r=0.336; p= 0.009) and inversely with LF component (r= -0.336; p=0.009). IL-6 correlated positively with HF component (r= 0.419; p=0.004) and inversely with LF component (r= -0.393; p= 0.007). However, in multivariate analysis only adiponectin correlated significantly with ANS measures. CONCLUSION: Adiponectin levels were higher in ECG and HF groups. IL-6 and TNF-alfa were higher in HF group. Higher levels of adiponectin were associated with reduced sympathetic activity and predominance of parasympathetic activity
158

Uticaj terapije inhibitora faktora tumorske nekroze na mineralnu koštanu gustinu i koštane biohemijske markere-prokolagen tip 1N-terminalni propeptid i beta-crosslaps kod bolesnica sa reumatoidnim artritisom / Effect of tumor necrosis factor inhibitor therapy on bone mineral density and biochemical markers in bone - procollagen type 1 Nterminal propeptide and beta-crosslaps in female patients suffering from rheumatoid arthritis

Janković Tanja 13 May 2020 (has links)
<p>Reumatoidni artritis (RA) je hronično inflamatorno oboljenje zglobova koji nastaje usled poremećaja u regulaciji imunskih mehanizama. TNF-alfa jedan je od ključnih medijatora inflamacije u RA, a koji preko složenih mehanizama podstiče aktivnost osteoklasta koji dovodi do poremećaja u procesu ko&scaron;tanog remodelovanja u pravcu povećane ko&scaron;tane resorpcije koji se klinički može pratiti određivanjem nivoa markera ko&scaron;tane resorpcije i ko&scaron;tanog formiranja u urinu i serumu. Primenom TNF inhibitora započeo je novi koncept lečenja RA. Cilj rada: Utvrditi razliku mineralne ko&scaron;tane gustine (BMDg/cm2) i vrednosti ko&scaron;tanih biohemijskih markera-prokolagen tip 1N-terminalni propeptid (P1NP) i beta-crosslapsa pre uvođenja terapije, i nakon godinu dana sprovedene terapije TNF inhibitorima. Metode: Studija je sprovedena u Specijalnoj bolnici za reumatske bolesti Novi Sad jednim delom kao retrospektivno, a drugim delom prospektivno istraživanje, koje je obuhvatilo 50 bolesnica sa dijagnozom reumatoidnog artritisa kod kojih je postojala indikacija za uvođenje lekova iz grupe TNF inhibitora. Da bi u&scaron;le u studiju bolesnice su morale da ispune određene uključne/isključne kriterijume koji su bili vezani za dužinu trajanja RA i menopauze, način lečenja RA, stepen o&scaron;tećenja zglobova i prisutnost drugih oboljenja sa reperkusijom na ko&scaron;tano tkivo. Pored reumatolo&scaron;kog i fizikalnog pregleda određivani su faktori rizika za osteoporozu i prelome. Na početku i na kraju godinu dana po uvođenju terapije TNF inhibitora rađena je osteodenzitometrija na aparatu tipa &bdquo;Lunar&ldquo; merena na lumbalnoj kičmi i kuku kao i određivanje biohemijskih markera u serumu prokolagen tip 1 N-terminalni propeptid (P1NP) i betacrosslapsa ECLIA metodom. Rezultati: Prosečna starost bolesnica bila je 51,5 godina koje su u 84%, bolovale od RA do 5 godina kod kojih je u najvećem procentu dužina trajanja menopauze bila do dve godine, a u svojoj terapiji pored metotreksata su imale uključen TNF inhibitor, Etanercept 34%, Adalimubam 46%, Golimubam 9% i 2% Infliksimab.Pre uvođenja biolo&scaron;ke terapije najveći broj bolesnica 80% imalo je osteopeniju, 14% normalan nalaz, dok je osteoporoza zabeležena kod 6% bolesnica. Na kraju jednogodi&scaron;nje primene TNF inhibitora 18% bolesnica je imalo normalan osteodenzitometrijski nalaz, 78 % osteopeniji, a 4% osteoporozu. Ova promena je statistički značajna ( p=0,000). Nakon jednogodi&scaron;nje primene TNF inhibitora nije do&scaron;lo do smanjenja vrednosti BMD (g/cm&sup2;) merenog na lumbalnom delu kičme i kuka. Beleži se statističko značajno povećanje vrednosti T- skora (SD) merenog na lumbalnom delu kičme i vratu butne kosti. Vrednost ko&scaron;tanih biohemijskih markera P1NP i beta crosslapsa značajno su povećani nakon jednogodi&scaron;nje primene TNF inhibitora, pri čemu se beleži veće povećanje biohemijskog markera ko&scaron;tane sinteze, P1NP. Zaključak: Savremeni pristup lečenja reumatoidnog artritisa podrazumeva primenu biolo&scaron;kih lekova kao &scaron;to su TNF inhibitori koji značajno suzbijaju inflamaciju i dovode do smanjenja odnosa RANKL/OPG sistema, čime se inhibira dejstvo osteoklasta i sprečava gubitak mineralne ko&scaron;tane gustine. Primena TNF inhibitora nakon godinu dana sprečila je pad vrednosti BMD (g/cm&sup2;), povećana je vrednost T- skora (SD) i vrednosti ko&scaron;tanih biohemijskih markera, posebno markera ko&scaron;tane sinteze. Uprkos velikom broju studija vezanih za dejstvo TNF inhibitora na kost, za sada nema dovoljan broj istraživanja o njegovom uticaju na sprečavanju osteoporoze i preloma kostiju i nivou vrednosti ko&scaron;tanih biohemijskih markera posebno u dužem periodu praćenja, &scaron;to će biti verovatno predmet daljih istraživanja.</p> / <p>Rheumatoid arthritis (RA) is a chronic inflammatory joint disease resulting from compromised regulation of immune mechanisms. TNF-alpha is one of the key inflammation mediators in RA that, through complex mechanisms stimulates osteoclast activity, thereby modifying the bone remodeling process in the direction of increased bone resorption that can be clinically monitored by determining the level of bone resorption and bone formation markers in urine and serum. Use of TNF has initiated a new concept in RA treatment. Aims: To determine the differences in bone mineral density (BMD, g/cm2) and values of biochemical markers in bone procollagentype 1 N-terminal propeptide(P1NP) and betacrosslaps before and after yearlong TNF inhibitor therapy. Methods: The study was conducted at the Special Hospital for Rheumatic Diseases Novi Sad partly as retrospective and partly as prospective research, which involved 50 female patients diagnosed with rheumatoid arthritis in whom introduction of medications from the TNF inhibitor group was indicated. To be included in the study, patients had to meet certain inclusion/exclusion criteria related to RA and menopause duration, RA treatment, degree of joint impairment, and presence of comorbidities with repercussions for bone tissues. In addition to rheumatological and physical examinations, risk factors for osteoporosis and fractures were determined. At the beginning and one year after commencing TNF inhibitor therapy, osteodensitometry was performed using &ldquo;Lunar&rdquo; apparatus, taking measurements on lumbar spine and hip, and serum levels of biochemical markers procollagentype 1 Nterminal propeptide(P1NP) and beta-crosslaps were determined via ECLIA method. Results: Mean patient age was 51.5 years, 84% of whom suffered from RA for up to 5 years, and in the greatest percentage experienced menopause for two years, receiving therapy that in addition to methotrexate included a TNF inhibitor, Etanercept 34%, Adalimumab 46%, Golimumab 9%, and 2% Infliximab. Prior to commencing biological therapy, majority of patients 80% suffered from osteopenia, 14% had normal findings, and osteoporosis was recorded in 6% of patients. At the end of yearlong TNF inhibitor therapy, 18% of patients had normal osteodensitometry findings, 78% had osteopenia and 4% osteoporosis. This change was statistically significant (p = 0.000). As a result of yearlong TNF inhibitor therapy no reduction occurred in BMD (g/cm&sup2;) values in lumbar spine and hip. Statistically significantly higher T scores (SD) pertaining to lumbar spine and femur were measured. Values of biochemical markers P1NP and beta-crosslaps significantly improved after yearlong TNF inhibitor therapy, whereby a greater increase was recorded in the biochemical bone synthesis marker, P1NP. Conclusion: Advanced rheumatoid arthritis treatment involves the use of biological compounds such as TNF inhibitors that significantly suppress inflammation and reduce the RANKL/OPG ratio, thereby inhibiting osteoclast activity and preventing bone mineral loss. TNF inhibitor therapy after one year prevented reduction in the BMD (g/cm&sup2;) levels, while increasing the T score (SD) and bone biochemical marker values, bone synthesis marker in particular. Despite a large number of studies related to the TNF inhibitor effect on bone, there is presently not enough research on its influence on osteoporosis and bone fracture prevention and bone biochemical marker levels, especially over longer periods, which will likely be the topic of further research.</p>
159

Serotype Cross-Reactive CD8+ T Cell Response to Heterologous Secondary Dengue Virus Infections in Humans: a Dissertation

Bashyam, Hema Sundara 18 October 2006 (has links)
The generation of memory T cells following primary exposure to a pathogen is a critical feature of the vertebrate immune system which has evolved as a protective mechanism in order to defend the host against repeated assaults by the patnogen. Memory T cells are long-lived, undergo rapid proliferation upon re-activation, mediate a robust secondary response and clear the pathogen much more efficiently. These aspects have made the generation of memory T cells an attractive goal for the production of both prophylactic and therapeutic vaccines. However, the degeneracy of the T cell receptor, whereby a given T cell recognizes more than one epitope, allows the T cell to be modulated by epitope variants which could be self-ligands, ligands related to the original epitope but altered in sequence, or completely unrelated epitopes. Experiments in both mice and humans show that such cross-reactive stimulation of memory T cells results in complete, partial, or no activation of T cells, and in some cases, even alters the functional identity of the T cell (for example, T helper 1 cells start secreting IL-4, IL-5 and become part of a T helper 2 response). In the context of secondary infection of immune organisms with pathogens containing mutated or related T cell epitopes, such alterations at the cellular level translate into drastic changes in the overall clinical outcome of the infection. Thus, the presence of cross-reactive T cells in the memory population implies that the protective or pathologic nature of the secondary immune response is a consequence of the host's infection history. Although several murine models of heterologous infection resulting in altered pathological outcome have been studied, the exact immune correlates of protection versus immunopathology are still unclear. This thesis addresses this issue in dengue virus infections in humans. Dengue fever (DF) and Dengue Hemorrhagic Fever (DHF) are two disease manifestations caused by infections of humans by the dengue viruses. These are a group of 4 serologically distinct flaviviruses (D1-4) which often co-circulate among endemic populations. While primary infection with any of the four serotypes can result in the more severe clinical disease characterized by DHF, epidemiological data from several outbreaks show that 80% - 90% of DHF cases occur among individuals with secondary infection. This implies that prior immunity to dengue is actually a risk factor for developing severe disease. In these DHF cases, there are increased numbers of CD69+ CD8+ T cells in circulation, with increases observed in the frequency of epitope-specific T cells, and the serum levels of several T cell produced cytokines, chemokines, and immune receptors are highly elevated. Since the four serotypes share 65% - 75% amino acid sequence homology, the possibility that unconserved T cell epitope sequences stimulated cross-reactive responses was borne out in in vitroexaminations. In these studies, peripheral blood mononuclear cells (PBMC) and cloned T cells from both vaccinated and infected donors contained large populations of memory T cells that were cross-reactive for heterologous viral serotypes in proliferation and CTL assays. These data suggest that the severity of disease seen in DHF patients can be attributed to an immunopathologic secondary response during heterologous infection, and highlight a role for serotype cross-reactive T cells in this process. This thesis addresses the hypothesis that the recognition of the natural variants of dengue virus T cell epitopes by serotype cross-reactive CD8+ T cells of a dengue-immune donor results in an altered secondary response profile, with the changes reflected in both the quantitative and qualitative nature of the response. In order to compare the functional profile of the secondary response of dengue-immune PBMC re-activated with heterologous serotypes, we focused on a panel of 4 donors who were vaccinated with live attenuated monovalent vaccines corresponding to D1, D2, or D4 serotypes. We screened a panel of peptides predicted to bind to HLA-A*0201 for cytokine responses and identified 4 novel epitopes that were highly immunogenic in all four donors. Direct ex vivo stimulation of donor PBMC with the heterologous sequences of these epitopes also showed sizeable serotype cross-reactive T cell populations. CFSE- and intracellular staining for cytokines and chemokines showed that these cross-reactive T cells not only expanded but also produced IFNγ, TNFα, and MIP-1β. Multi-parameter staining revealed functionally diverse populations comprised of single cytokine (IFNγ+, TNFα+, MIP-1β+, double cytokine (IFNγ+TNFα+, IFNγ+MIP-1β+, TNFα+MIP-1β+, and triple cytokine (IFNγ+TNFα+MIP-1β+ secreting sub-sets. Stimulation with the epitope variants altered the magnitude of the overall response as well as the relative sizes of these sub-sets. The patterns of responses revealed the effects of epitope immunogenicity, infection history and donor-specific variability. All 4 donors showed the highest cytokine response to a -single epitope (NS4b 2353). The same two peptide variants (D2 NS4a 2148 and D3 NS4b 2343) induced the highest response in all 4 donors regardless of the serotype of primary dengue infection. Interestingly, the epitope variants which showed the highest immunogenecity in our donors corresponded to the D2 and D3 serotypes which have been documented as being more virulent as well as a viral risk factor for DHF. In one donor, the response to all peptide variants was dominated by the same cytokine sub-sets. These data suggested that the dengue-immune memory T cell repertoire was functionally diverse and underwent alterations in size after secondary stimulation. Therefore, we also investigated the effect of epitope variants on dengue-specific CD8+T cell clones isolated from vaccinated and infected donors in order to determine if epitope variants induced altered functional outcomes at the clonal level. The epitope variants functioned either as strong agonists (particularly the D2 and D3 sequences), partial agonists, or null ligands. Some variants were able to induce cytolysis but not other effector functions at low concentrations. The variant ligands also influenced the hierarchy of cytokine responses within each clone. The third part of this thesis focused on the characterization of the frequency and phenotypic profile of epitope-specific CD8+ T cells in patients with DHF and DF at different times in the disease course in order to better understand the kinetics of the response and delineate any differences between the immune profile of severe vs. moderate disease. Tetramer staining for a previously identified HLA-B*07 restricted epitope was combined with staining for activation markers (CD69, CD38, HLA-DR), homing receptors (CCR7, CD62L), and programmed death receptor 1 (PD-1). The DHF subjects had early T cell activation with higher frequencies of tetramer+CD69+ cells as compared to DF subjects, in whom T cell frequencies peaked around the time of defervescence. While each subject had a unique phenotypic profile of tetramer+ cells, there was a difference between DF and DHF subjects in terms of CCR 7 expression; all subjects expressed low levels of CCR7 during acute illness but only the DHF subjects did not show upregulation of CCR7 on tetramer+ cells during convalescence. These data suggest that there is a sustained alteration in memory phenotype in those who recovered from severe dengue disease. A majority of the tetramer+cells also expressed PD-1 during acute illness but not during convalescence. Double-staining with variant tetramers allowed us to directly visualize serotype cross-reactivity of the epitope-specific population, and showed that secondary stimulation did induce the expansion of cells with low avidity for that secondary serotype and higher avidity to the variant. Furthermore, the ratios of these sub-sets changed during the course of the response. Taken together, these studies suggest that the immune response to heterologous secondary dengue infection is mediated by a heterogeneous population of serotype-cross reactive T cells that have different functional avidities to epitope variants and is influenced by the serotype of the secondary infection as well as the prior infection history of the individual. The preferential expansion of clones which secrete IFNγ but not inflammatory MIP-1β or TNFα or a repertoire characterized by a higher ratio of cytolytic to cytokine producing clones could limit immune mediated damage while efficiently clearing the virus. This information will be useful in the design of vaccine strategies aimed at inducing protective cross-reactive responses against all 4 dengue serotypes while preventing immunopathological outcomes following secondary infection.
160

Mécanismes moléculaires régulant la pathologie dendritique dans la rétine adulte lésée in vivo

Morquette, Junie Barbara 12 1900 (has links)
No description available.

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