Caracterização genotípica de amostras Escherichia coli isoladas de mastite bovina

Submitted by Gilvan Almeida ([email protected]) on 2017-01-30T17:56:17Z No. of bitstreams: 2 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Caracterização genótipa....pdf: 106100 bytes, checksum: b38badac68d95be983b636ef6f242536 (MD5)Approved for entry into archive by Fátima Lopes ([email protected]) on 2018-04-06T18:02:28Z (GMT) No. of bitstreams: 2 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Caracterização genótipa....pdf: 106100 bytes, checksum: b38badac68d95be983b636ef6f242536 (MD5)Made available in DSpace on 2018-04-06T18:02:28Z (GMT). No. of bitstreams: 2 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Caracterização genótipa....pdf: 106100 bytes, checksum: b38badac68d95be983b636ef6f242536 (MD5) Previous issue date: 2011Universidade Federal de Mato Grosso. Sinop, MT, BrasilUniversidade Federal Rural do Rio de Janeiro. Curso de Pós-Graduação em Ciências Veterinárias. Seropédica, RJ, BrasilFundação Oswaldo Cruz. Escola Nacional de Saúde Pública Sergio Arouca. Rio de Janeiro, RJ, BrasilFundação Oswaldo Cruz. Escola Nacional de Saúde Pública Sergio Arouca. Rio de Janeiro, RJ, BrasilEscherichia coli samples isolated from cases of dairy mastitis in municipalities of Rio de Janeiro State, Brazil, were genotypically compared and Shiga-toxin genes were detected and their prevalence evaluated. Genetically related samples were verified and the referred genes were detected in 14.28% of the cases

Combined GS-4774 and Tenofovir Therapy Can Improve HBV-Specific T-Cell Responses in Patients With Chronic Hepatitis

Background & Aims: One strategy to treat chronic hepatitis B virus (HBV) infection could be to increase the functions of virus-specific T cells. We performed a multicenter phase 2 study to evaluate the safety and efficacy of GS-4774, a yeast-based therapeutic vaccine engineered to express HBV antigens, given with tenofovir disoproxil fumarate (TDF) to untreated patients with chronic HBV infection. Methods: We performed an open-label study at 34 sites in Canada, Italy, New Zealand, Romania, South Korea, and United States from July 2014 to August 2016. Adults who were positive for HB surface antigen (HBsAg) > 6 months and levels of HBV DNA 652000 IU/mL who had not received antiviral treatment for HBV within 3 months of screening were randomly assigned (1:2:2:2) to groups given oral TDF 300 mg daily alone (n = 27; controls) or with 2, 10, or 40 yeast units GS-4774 (n = 168), administered subcutaneously every 4 weeks until week 20 for a total of 6 doses. Blood samples were collected and analyzed and patients received regular physical examinations. Efficacy was measured by decrease in HBsAg from baseline to week 24. Specific responses to HBV (production of interferon gamma [IFNG], tumor necrosis factor [TNF], interleukin 2 [IL2], and degranulation) were measured in T cells derived from 12 HBeAg-negative patients with genotype D infections, after overnight or 10 days of stimulation of peripheral blood mononuclear cells with peptides from the entire HBV proteome. T-regulatory cells were analyzed for frequency and phenotype. Data from studies of immune cells were compared with data on reductions in HBsAg, HBV DNA, and alanine aminotransferase in blood samples from patients. Results: GS-4774 was safe and well tolerated but did not produce significant decreases in levels of HBsAg. Production of IFNG, TNF, and IL2 increased significantly at weeks 24 and 48, compared with baseline, in HBV-specific CD8+ T cells from patients given GS-4774 but not from controls. GS-4774 had greater effects on CD8+ than CD4+ T cells, which were not affected at all or very weakly by TDF with or without GS-4774. GS-4774 did not affect responses of T cells to other viruses tested. HBV core peptides induced the greatest production of IFNG by T cells following overnight stimulation, whereas HBV envelope antigens did not induce a response. Following 10 days of stimulation, production of IFNG and TNF increased with time of exposure to GS-4774; the greatest levels of responses were to HBV envelope antigens followed by core and polymerase peptides. We observed a correlation in patients given GS-4774 between increased T-cell functions and reductions in numbers of T-regulatory cells. Conclusions: In a phase 2 study of patients with chronic HBV infection given TDF with or without GS-4774, we found that vaccination can increase production of IFNG, TNF, and IL2 by CD8+ T cells exposed to antigenic peptides, with little effect on CD4+ T cells. Although GS-4774 did not reduce levels of HBsAg in patients, its strong immune stimulatory effect on CD8+ T cells might be used in combination with other antiviral agents to boost the antivirus immune response. Clinicaltrials.gov no: NCT02174276

The influence of the human genome on chronic viral hepatitis outcome A influência do genoma humano no curso das hepatites virais crônicas

The mechanisms that determine viral clearance or viral persistence in chronic viral hepatitis have yet to be identified. Recent advances in molecular genetics have permitted the detection of variations in immune response, often associated with polymorphism in the human genome. Differences in host susceptibility to infectious disease and disease severity cannot be attributed solely to the virulence of microbial agents. Several recent advances concerning the influence of human genes in chronic viral hepatitis B and C are discussed in this article: a) the associations between human leukocyte antigen polymorphism and viral hepatic disease susceptibility or resistance; b) protective alleles influencing hepatitis B virus (HBV) and hepatitis C virus (HCV) evolution; c) prejudicial alleles influencing HBV and HCV; d) candidate genes associated with HBV and HCV evolution; d) other genetic factors that may contribute to chronic hepatitis C evolution (genes influencing hepatic stellate cells, TGF-beta1 and TNF-alpha production, hepatic iron deposits and angiotensin II production, among others). Recent discoveries regarding genetic associations with chronic viral hepatitis may provide clues to understanding the development of end-stage complications such as cirrhosis or hepatocellular carcinoma. In the near future, analysis of the human genome will allow the elucidation of both the natural course of viral hepatitis and its response to therapy.<br>Os mecanismos que determinam o clearance ou a persistência da infecção viral nas hepatites virais crônicas não estão ainda bem identificados. O progresso no conhecimento sobre as ferramentas genéticas moleculares tem permitido detectar variações na resposta imune, que freqüentemente são associadas com polimorfismos do genoma humano. As diferenças na susceptibilidade do hospedeiro para as doenças infecciosas e a intensidade das doenças não podem ser atribuídas apenas à virulência do agente microbiano. Neste artigo são discutidos vários avanços recentes no conhecimento sobre a influência dos genes humanos nas hepatites crônicas B e C, a saber: a) As associações entre os polimorfismos HLA e a susceptibilidade ou resistência às doenças hepáticas virais; b) Alelos protetores influenciando as hepatites virais B (HVB) e C (HVC); c) Alelos prejudiciais influenciando HVB e HVC; d) Genes candidatos associados com a evolução clínica de HVB e HVC (genes que influenciam as células estreladas do fígado, a produção de TGF-beta1 e TNF-alfa, os depósitos de ferro hepáticos, a produção de angiotensina II, entre outros). O conhecimento das associações genéticas com as hepatites virais crônicas pode fornecer indícios para o pleno entendimento de como se desenvolvem as suas complicações terminais, como a cirrose e o carcinoma hepatocelular. Em futuro próximo, a análise do genoma humano será capaz de elucidar o curso natural de uma hepatite viral, bem como a sua resposta à terapêutica