878 resultados para Viral Replication


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Chikungunya virus (CHIKV) is a mosquito-borne arthrogenic alphavirus that causes acute febrile illness in humans accompanied by joint pains and in many cases, persistent arthralgia lasting weeks to years. The re-emergence of CHIKV has resulted in numerous outbreaks in the eastern hemisphere, and threatens to expand in the foreseeable future. Unfortunately, no effective treatment is currently available. The present study reports the use of resazurin in a cell-based high-throughput assay, and an image-based high-content assay to identify and characterize inhibitors of CHIKV-infection in vitro. CHIKV is a highly cytopathic virus that rapidly kills infected cells. Thus, cell viability of HuH-7 cells infected with CHIKV in the presence of compounds was determined by measuring metabolic reduction of resazurin to identify inhibitors of CHIKV-associated cell death. A kinase inhibitor library of 4,000 compounds was screened against CHIKV infection of HuH-7 cells using the resazurin reduction assay, and the cell toxicity was also measured in non-infected cells. Seventy-two compounds showing >= 50% inhibition property against CHIKV at 10 mu M were selected as primary hits. Four compounds having a benzofuran core scaffold (CND0335, CND0364, CND0366 and CND0415), one pyrrolopyridine (CND0545) and one thiazol-carboxamide (CND3514) inhibited CHIKV-associated cell death in a dose-dependent manner, with EC50 values between 2.2 mu M and 7.1 mu M. Based on image analysis, these 6 hit compounds did not inhibit CHIKV replication in the host cell. However, CHIKV-infected cells manifested less prominent apoptotic blebs typical of CHIKV cytopathic effect compared with the control infection. Moreover, treatment with these compounds reduced viral titers in the medium of CHIKV-infected cells by up to 100-fold. In conclusion, this cell-based high-throughput screening assay using resazurin, combined with the image-based high content assay approach identified compounds against CHIKV having a novel antiviral activity -inhibition of virus-induced CPE - likely by targeting kinases involved in apoptosis.

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Globally, hepatitis C virus (HCV) infection affects approximately 130 million people and 3 million new infections occur annually. HCV is also recognized as an important cause of chronic liver disease in children. The absence of proofreading properties of the HCV RNA polymerase leads to a highly error prone replication process, allowing HCV to escape host immune response. The adaptive nature of HCV evolution dictates the outcome of the disease in many ways. Here, we investigated the molecular evolution of HCV in three unrelated children who acquired chronic HCV infection as a result of mother-to-child transmission, two of whom were also coinfected with HIV-1. The persistence of discrete HCV variants and their population structure were assessed using median joining network and Bayesian approaches. While patterns of viral evolution clearly differed between subjects, immune system dysfunction related to HIV coinfection or persistent HCV seronegativity stand as potential mechanisms to explain the lack of molecular evolution observed in these three cases. In contrast, treatment of HCV infection with PegIFN, which did not lead to sustained virologic responses in all 3 cases, was not associated with commensurate variations in the complexity of the variant spectrum. Finally, the differences in the degree of divergence suggest that the mode of transmission of the virus was not the main factor driving viral evolution. (C) 2013 Elsevier B. V. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Background: Acute viral bronchiolitis is a respiratory disease with high morbidity that affects newborn in the first two years of life. Its treatment with physiotherapy has been highlighted as an important tool, however, there is no consensus regarding its effects on patients improvement. We aimed to evaluate the physiological parameters before and after the procedure respiratory therapy in newborn with acute viral bronchiolitis. Method: This was a cross sectional observational study in 30 newborns with acute viral bronchiolitis and indicated for physiotherapy care in a hospitalized Urgency and Emergency Unit. It was collected the clinical data of newborn through evaluation form, and we measured heart rate (HR), oxygen saturation (SpO2) and respiratory rate (RR). We measured the variables before physiotherapy treatment, 3, 6 and 9 minutes after the physiotherapy treatment. Results: There has been no change in HR, however, we observed a decrease in RR at 6 and 9 min compared to 3 min and increase in SpO2 at 3, 6 and 9 min compared to before physiotherapy. Conclusion: Respiratory physiotherapy may be an effective therapy for the treatment of newborn with Acute Viral Bronchitis.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Hepatitis C virus (HCV) infection represents an important public health problem worldwide. Reduction of HCV morbidity and mortality is a current challenge owned to several viral and host factors. Virus molecular evolution plays an important role in HCV transmission, disease progression and therapy outcome. The high degree of genetic heterogeneity characteristic of HCV is a key element for the rapid adaptation of the intrahost viral population to different selection pressures (e.g., host immune responses and antiviral therapy). HCV molecular evolution is shaped by different mechanisms including a high mutation rate, genetic bottlenecks, genetic drift, recombination, temporal variations and compartmentalization. These evolutionary processes constantly rearrange the composition of the HCV intrahost population in a staging manner. Remarkable advances in the understanding of the molecular mechanism controlling HCV replication have facilitated the development of a plethora of direct-acting antiviral agents against HCV. As a result, superior sustained viral responses have been attained. The rapidly evolving field of anti-HCV therapy is expected to broad its landscape even further with newer, more potent antivirals, bringing us one step closer to the interferon-free era. (C) 2014 Baishideng Publishing Group Inc. All rights reserved.

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The feline leukemia virus (FeLV) was described in 1964 by William Jarrett and collaborators wen find viral particles attached to the membrane of lymphoblasts in cat with lymphoma. The virus belongs to the family Retroviridae, subfamily oncornavirus. With worldwide distribution, the occurrence of FeLV has 1.6% in healthy cats and 10.8% in sick cats in Brazil. The mortality of persistently viremic animals in catteries is about 50% in two years and 80% in three years. In catteries that have endemic feline Coronavirus (FCoV), FeLV and / or Feline Immunodeficiency Virus (FIV), the FeLV infection has greater contribution to mortality. The test for infection and FeLV positive cats segregation is the main way to prevent the spread of infection. The diagnostic methods are based on clinical signs and changes compatible with FeLV infection observed by physical examination, complete blood count, X-ray, bone marrow aspirate and biochemical. The viral p27 protein is produced in infected cells in high amounts and is found in abundance in the cytoplasm and in body fluids enabling diagnosed methods such as enzyme-linked immunosorbent assay - ELISA and direct immunofluorescence, detection of viral genome (Chain Reaction Polymerase - PCR) and detection of the virus by virus isolation. Although diagnostic tests are highly sensitive, it should be made more than a confirmatory test, especially serological due to variable characteristic of the progress of infection

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Indivíduos imunocomprometidos possuem maior risco de desenvolver linfomas associados ao EBV. A detecção desse vírus em sangue periférico e a determinação de sua carga viral podem ter importância na evolução clínica de indivíduos portadores do HIV. Foram avaliadas 156 amostras de pacientes HIVpositivos pela reação em cadeia da polimerase em tempo real (qPCR) para detecção e quantificação da carga viral do EBV. 123/156 (78,8%) casos apresentaram carga viral detectável para o EBV, sendo que a carga viral média foi de 6,9x10-3 cópias de EBV/célula. Foi detectada elevada carga viral do EBV em indivíduos com falha terapêutica ou sem HAART (p =0,0076), em coinfectados pelos EBVs 1 e 2 (p=0,0205), em pacientes com altas cargas de HIV (rho=0,27614, p=0,0005) e longos períodos de infecção pelo HIV (rho= 0,24164, p =0,0026) e os que apresentavam altos níveis de linfócitos T CD8 + (rho=0,19286, p =0,0159). A amplificação do gene EBNA-2 para realização da tipagem viral foi possível em 95/123 (77,2%) amostras, das quais 72 (75,8%) revelaram infecção pelo EBV-1, 9 (9,5%) pelo EBV-2 e 14 (14,7%) apresentavam coinfecção entre os EBVs 1 e 2. Esses dados estão de acordo com a literatura visto que o tipo 1 é predominante em países ocidentais e 70,0% da coorte era composta por indivíduos caucasianos e heterossexuais. A maioria dos pacientes que apresentaram coinfecção pelos EBVs 1 e 2 tiveram contagem de linfócitos T CD4 + entre 200 e 499 células/μL de sangue segundo classificação CDC (p =0,0272). Quanto a analise do gene BNLF-1, a amplificação foi possível em 99/123 (80,5%). Desses 50/99 (50,5%) apresentavam a deleção de 30pb no gene, enquanto 49/99 (49,5%) não a possuíam. Em conjunto, os resultados obtidos evidenciam deterioração do sistema imunitário, caracterizada...(Resumo completo, clicar acesso eletrônico abaixo)

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This study presents a new recombinant protein that acts as a powerful antiviral (rAVLO—recombinant Antiviral protein of Lonomia obliqua). It was able to reduce the replication by 106 fold for herpes virus and by 104 fold for rubella virus. RT-PCR of viral RNA rAVLO treated infected cells also showed similar rate of inhibition in replication. The analysis of this protein by bioinformatics suggests that this protein is globular, secreted with a signal peptide and has the ability to bind to MHC class I. It was found that there are several protein binding sites with various HLA and a prevalence of α-helices in the N-terminal region (overall classified as a α/β protein type). BLAST similarity sequence search for corresponding cDNA did not reveal a similar sequence in Genbank, suggesting that it is from a novel protein family. In this study we have observed that this recombinant protein and hemolymph has a potent antiviral action. This protein was produced in a baculovirus/Sf-9 system. Therefore, these analyses suggest that this novel polypeptide is a candidate as a broad spectrum antiviral.