105 research outputs found

    Raltegravir Is a Potent Inhibitor of XMRV, a Virus Implicated in Prostate Cancer and Chronic Fatigue Syndrome

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    Xenotropic murine leukemia-related retrovirus (XMRV) is a recently discovered retrovirus that has been linked to human prostate cancer and chronic fatigue syndrome (CFS). Both diseases affect a large fraction of the world population, with prostate cancer affecting one in six men, and CFS affecting an estimated 0.4 to 1% of the population.. We found that the retroviral integrase inhibitor, raltegravir, was potent and selective against XMRV at submicromolar concentrations, in MCF-7 and LNCaP cells, a breast cancer and prostate cancer cell line, respectively. Another integrase inhibitor, L-000870812, and two nucleoside reverse transcriptase inhibitors, zidovudine (ZDV), and tenofovir disoproxil fumarate (TDF) also inhibited XMRV replication. When combined, these drugs displayed mostly synergistic effects against this virus, suggesting that combination therapy may delay or prevent the selection of resistant viruses.If XMRV proves to be a causal factor in prostate cancer or CFS, these discoveries may allow for rational design of clinical trials

    Visualization of positive and negative sense viral RNA for probing the mechanism of direct-acting antivirals against hepatitis C virus

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    RNA viruses are highly successful pathogens and are the causative agents for many important diseases. To fully understand the replication of these viruses it is necessary to address the roles of both positive-strand RNA ((+)RNA) and negative-strand RNA ((-)RNA), and their interplay with viral and host proteins. Here we used branched DNA (bDNA) fluorescence in situ hybridization (FISH) to stain both the abundant (+)RNA and the far less abundant (-)RNA in both hepatitis C virus (HCV)- and Zika virus-infected cells, and combined these analyses with visualization of viral proteins through confocal imaging. We were able to phenotypically examine HCV-infected cells in the presence of uninfected cells and revealed the effect of direct-acting antivirals on HCV (+)RNA, (-)RNA, and protein, within hours of commencing treatment. Herein, we demonstrate that bDNA FISH is a powerful tool for the study of RNA viruses that can provide insights into drug efficacy and mechanism of action

    Metabolic regulation and production of oxygen reactive species during muscule contraction: effect of glycogen on intracellular redox state

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    O exercício físico prolongado reduz os estoques de glicogênio muscular. Nessas condições, os processos de fadiga muscular são estimulados coincidindo com um aumento na produção de espécies reativas de oxigênio. A suplementação de carboidratos ou de antioxidantes isoladamente contribui para a melhora da performance muscular, sugerindo um efeito importante da depleção de substrato (glicose) e do aumento da produção de EROs no desenvolvimento da fadiga muscular durante a atividade física. Embora o mecanismo seja desconhecido, estamos propondo neste estudo que uma maior disponibilidade de glicogênio poderia favorecer uma maior atividade da via das pentoses fosfato, aumentando a disponibilidade de NADPH e GSH no tecido muscular esquelético. Uma maior capacidade antioxidante aumentaria a capacidade do tecido muscular em atividade, mantendo o equilíbrio redox durante atividade física prolongada e melhorando o desempenho. Neste processo, o ciclo glicose-ácido graxo pode ser importante aumentando a oxidação de lipídio e reduzindo o consumo de glicogênio durante a atividade prolongada. Além disso, um aumento na produção de EROs pode reduzir a atividade de enzimas importantes do metabolismo celular incluindo a aconitase e a a-cetoglutarato desidrogenase, comprometendo a produção de energia oxidativa, via predominante na produção de ATP durante a atividade muscular prolongada.Fatigue is closely related to the depletion of glycogen in the skeletal muscle during prolonged exercise. Under this condition, the production of oxygen reactive species (ROS) is substantially increased. It has been shown that dietary supplementation of carbohydrate or antioxidant attenuates muscle fatigue during contraction. This suggests that glycogen availability and/or elevated ROS production plays an important role on muscle fatigue development during prolonged muscle activity. Although the mechanism is still unknown, we propose that elevated muscle glycogen availability may lead to a high activity of hexose monophosphate pathway, increasing the NADPH and glutathione concentration in the skeletal muscle tissue. Elevated antioxidant capacity would increase the muscle redox balance during muscle contraction, improving performance. In this process, the glucose-fatty acid cycle may be important to increase lipid oxidation and consequently decrease glycogen utilization during prolonged activity. In addition, an elevated ROS production could reduce the activity of key metabolic enzymes including aconitase and a-ketoglutarate dehydrogenase, decreasing the oxidative energy production in the skeletal muscle during prolonged activity.FAPESPCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)CNP

    Hepatitis B virus infection in Haemodialysis Centres from Santa Catarina State, Southern Brazil. Predictive risk factors for infection and molecular epidemiology.

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    BACKGROUND: Patients under haemodialysis are considered at high risk to acquire hepatitis B virus (HBV) infection. Since few data are reported from Brazil, our aim was to assess the frequency and risk factors for HBV infection in haemodialysis patients from 22 Dialysis Centres from Santa Catarina State, south of Brazil. METHODS: This study includes 813 patients, 149 haemodialysis workers and 772 healthy controls matched by sex and age. Serum samples were assayed for HBV markers and viraemia was detected by nested PCR. HBV was genotyped by partial S gene sequencing. Univariate and multivariate statistical analyses with stepwise logistic regression analysis were carried out to analyse the relationship between HBV infection and the characteristics of patients and their Dialysis Units. RESULTS: Frequency of HBV infection was 10.0%, 2.7% and 2.7% among patients, haemodialysis workers and controls, respectively. Amidst patients, the most frequent HBV genotypes were A (30.6%), D (57.1%) and F (12.2%). Univariate analysis showed association between HBV infection and total time in haemodialysis, type of dialysis equipment, hygiene and sterilization of equipment, number of times reusing the dialysis lines and filters, number of patients per care-worker and current HCV infection. The logistic regression model showed that total time in haemodialysis, number of times of reusing the dialysis lines and filters, and number of patients per worker were significantly related to HBV infection. CONCLUSIONS: Frequency of HBV infection among haemodialysis patients at Santa Catarina state is very high. The most frequent HBV genotypes were A, D and F. The risk for a patient to become HBV positive increase 1.47 times each month of haemodialysis; 1.96 times if the dialysis unit reuses the lines and filters > or = 10 times compared with haemodialysis units which reuse < 10 times; 3.42 times if the number of patients per worker is more than five. Sequence similarity among the HBV S gene from isolates of different patients pointed out to nosocomial transmission

    Regulation of glucose and fatty acid metabolism in skeletal muscle during contraction

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    O ciclo glicose-ácido graxo explica a preferência do tecido muscular pelos ácidos graxos durante atividade moderada de longa duração. Em contraste, durante o exercício de alta intensidade, há aumento na disponibilidade e na taxa de oxidação de glicose. A produção de espécies reativas de oxigênio (EROs) durante a atividade muscular sugere que o balanço redox intracelular é importante na regulação do metabolismo de lipídios/carboidratos. As EROs diminuem a atividade do ciclo de Krebs e aumentam a atividade da proteína desacopladora mitocondrial. O efeito oposto é esperado durante a atividade moderada. Assim, as questões levantadas nesta revisão são: Por que o músculo esquelético utiliza preferencialmente os lipídios no estado basal e de atividade moderada? Por que o ciclo glicose-ácido graxo falha em exercer seus efeitos durante o exercício intenso? Como o músculo esquelético regula o metabolismo de lipídios e carboidratos em regime envolvendo o ciclo contração-relaxamento555303313CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informaçãoThe glucose-fatty acid cycle explains the preference for fatty acid during moderate and long duration physical exercise. In contrast, there is a high glucose availability and oxidation rate in response to intense physical exercise. The reactive oxygen species (ROS) production during physical exercise suggests that the redox balance is important to regulate of lipids/carbohydrate metabolism. ROS reduces the activity of the Krebs cycle, and increases the activity of mitochondrial uncoupling proteins. The opposite effects happen during moderate physical activity. Thus, some issues is highlighted in the present review: Why does skeletal muscle prefer lipids in the basal and during moderate physical activity? Why does glucose-fatty acid fail to carry out their effects during intense physical exercise? How skeletal muscles regulate the lipids and carbohydrate metabolism during the contraction-relaxation cycle

    Regulation of glucose and fatty acid metabolism in skeletal muscle during contraction

    Get PDF
    O ciclo glicose-ácido graxo explica a preferência do tecido muscular pelos ácidos graxos durante atividade moderada de longa duração. Em contraste, durante o exercício de alta intensidade, há aumento na disponibilidade e na taxa de oxidação de glicose. A produção de espécies reativas de oxigênio (EROs) durante a atividade muscular sugere que o balanço redox intracelular é importante na regulação do metabolismo de lipídios/carboidratos. As EROs diminuem a atividade do ciclo de Krebs e aumentam a atividade da proteína desacopladora mitocondrial. O efeito oposto é esperado durante a atividade moderada. Assim, as questões levantadas nesta revisão são: Por que o músculo esquelético utiliza preferencialmente os lipídios no estado basal e de atividade moderada? Por que o ciclo glicose-ácido graxo falha em exercer seus efeitos durante o exercício intenso? Como o músculo esquelético regula o metabolismo de lipídios e carboidratos em regime envolvendo o ciclo contração-relaxamento.The glucose-fatty acid cycle explains the preference for fatty acid during moderate and long duration physical exercise. In contrast, there is a high glucose availability and oxidation rate in response to intense physical exercise. The reactive oxygen species (ROS) production during physical exercise suggests that the redox balance is important to regulate of lipids/carbohydrate metabolism. ROS reduces the activity of the Krebs cycle, and increases the activity of mitochondrial uncoupling proteins. The opposite effects happen during moderate physical activity. Thus, some issues is highlighted in the present review: Why does skeletal muscle prefer lipids in the basal and during moderate physical activity? Why does glucose-fatty acid fail to carry out their effects during intense physical exercise? How skeletal muscles regulate the lipids and carbohydrate metabolism during the contraction-relaxation cycle

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    Fine Tuning of the Lactate and Diacetyl Production through Promoter Engineering in Lactococcus lactis

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    Lactococcus lactis is a well-studied bacterium widely used in dairy fermentation and capable of producing metabolites with organoleptic and nutritional characteristics. For fine tuning of the distribution of glycolytic flux at the pyruvate branch from lactate to diacetyl and balancing the production of the two metabolites under aerobic conditions, a constitutive promoter library was constructed by randomizing the promoter sequence of the H2O-forming NADH oxidase gene in L. lactis. The library consisted of 30 promoters covering a wide range of activities from 7,000 to 380,000 relative fluorescence units using a green fluorescent protein as reporter. Eleven typical promoters of the library were selected for the constitutive expression of the H2O-forming NADH oxidase gene in L. lactis, and the NADH oxidase activity increased from 9.43 to 58.17-fold of the wild-type strain in small steps of activity change under aerobic conditions. Meanwhile, the lactate yield decreased from 21.15±0.08 mM to 9.94±0.07 mM, and the corresponding diacetyl production increased from 1.07±0.03 mM to 4.16±0.06 mM with the intracellular NADH/NAD+ ratios varying from 0.711±0.005 to 0.383±0.003. The results indicated that the reduced pyruvate to lactate flux was rerouted to the diacetyl with an almost linear flux variation via altered NADH/NAD+ ratios. Therefore, we provided a novel strategy to precisely control the pyruvate distribution for fine tuning of the lactate and diacetyl production through promoter engineering in L. lactis. Interestingly, the increased H2O-forming NADH oxidase activity led to 76.95% lower H2O2 concentration in the recombinant strain than that of the wild-type strain after 24 h of aerated cultivation. The viable cells were significantly elevated by four orders of magnitude within 28 days of storage at 4°C, suggesting that the increased enzyme activity could eliminate H2O2 accumulation and prolong cell survival
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