160 research outputs found

    Miniaturization of aqueous two-phase extraction for biological applications

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    Aqueous two-phase extraction (ATPE) is a biocompatible liquid-liquid (L-L) separation technique that has been under research for several decades towards the purification of biomolecules, ranging from small metabolites to large animal cells. More recently, with the emergence of rapid-prototyping techniques for fabrication of microfluidic structures with intricate designs, ATPE gained an expanded range of applications utilizing physical phenomena occurring exclusively at the microscale. Studies of ATPSs at nanoliter-scale are further extending the range of applications of these systems by taking advantage of rapid diffusion times, increased degree of control of individual liquid streams and droplets, continuous flow and the integration of multi-dimensional separation modes. Several examples of microfluidic ATPS platforms are described. The partition of molecules between two co-flowing liquid streams confined within a microchannel was successfully demonstrated by the on-line extraction of a fluorescein isothiocyanate (FITC) labeled immunoglobulin G (IgG) from a salt rich flow to a PEG rich flow. IgG diffusion to the PEG-rich phase was complete after 16 cm of channel using flow rates of 1 and 0.2 μL/min for the salt and PEGrich phases respectively. Besides proteins, ATPS have also been used to separate other more complex biomolecules in microfluidics such as virus-like particles. The potential of miniaturization as a high-throughput screening tool has also been explored. The developed setup allowed the screening of a wide range of concentrations inside the microchannel by varying the flow rates of the solutions while using sub-mL volumes for each ATPS-forming system. As a novel demonstration of the integrative potential of ATPE as a microfluidic sample preparation module, a microfluidic device comprising two modules was developed and used to perform a complex matrix clean-up in-line with an immunoassay. References: Silva, D. F., Azevedo, A. M., Fernandes, P., Chu, V. et al., Design of a microfluidic platform for monoclonal antibody extraction using an aqueous two-phase system. J. Chromatogr. A 2012, 1249, 1–7. Jacinto, M. J., Soares, R. R. G., Azevedo, A. M., Chu, V. et al., Optimization and miniaturization of aqueous two phase systems for the purification of recombinant human immunodeficiency virus-like particles from a CHO cell supernatant. Sep. Purif. Technol. 2015, 154, 27–35. Silva, D. F. C., Azevedo, A. M., Fernandes, P., Chu, V. et al., Determination of aqueous two phase system binodal curves using a microfluidic device. J. Chromatogr. A 2014, 1370, 115–120. Soares, R. R., Novo, P., Azevedo, A. M., Fernandes, P. et al., On-chip sample preparation and analyte quantification using a microfluidic aqueous two-phase extraction coupled with an immunoassay. Lab Chip 2014, 14, 4284–429

    Intra-promoter switch of transcription initiation sites in proliferation signaling-dependent RNA metabolism

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    Global changes in transcriptional regulation and RNA metabolism are crucial features of cancer development. However, little is known about the role of the core promoter in defining transcript identity and post-transcriptional fates, a potentially crucial layer of transcriptional regulation in cancer. In this study, we use CAGE-seq analysis to uncover widespread use of dual-initiation promoters in which non-canonical, first-base-cytosine (C) transcription initiation occurs alongside first-base-purine initiation across 59 human cancers and healthy tissues. C-initiation is often followed by a 5' terminal oligopyrimidine (5'TOP) sequence, dramatically increasing the range of genes potentially subjected to 5'TOP-associated post-transcriptional regulation. We show selective, dynamic switching between purine and C-initiation site usage, indicating transcription initiation-level regulation in cancers. We additionally detail global metabolic changes in C-initiation transcripts that mark differentiation status, proliferative capacity, radiosensitivity, and response to irradiation and to PI3K-Akt-mTOR and DNA damage pathway-targeted radiosensitization therapies in colorectal cancer organoids and cancer cell lines and tissues.</p

    Exercício de intensidade moderada durante a gravidez é seguro para o feto? Ensaio clínico aberto

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    To determine the effect of treadmill walking on maternal heart rate (MHR) and cardiotocographic parameters (basal fetal heart rate [FHR], active fetal movements [AFM], number of accelerations and decelerations, and short-term variation [STV] and long-term variation [LTV] of fetal heart rate) in pregnant women at 36 weeks. Methods A nonrandomized, open clinical trial involving 88 healthy pregnant women submitted to moderate intensity walking and computed cardiotocography in 3 20-minute periods (resting, treadmill walking, and postexercise recovery). Results The mean FHR decreased during walking (resting: 137 bpm; treadmill: 98 bpm; recovery: 140 bpm; p <0.001), with bradycardia occurring in 56% of the fetuses in the first 10minutes of exercise, and in 47% after 20minutes. Bradycardia was not detected in the other phases. The mean STV and HV were 7.9, 17.0, and 8.0 milliseconds ( p <0.001) and 7.6, 10.8 and 7.6 bpm ( p =0.002) in the resting, walking and recovery phases, respectively. The mean number of fetal movements in 1 hour was 29.9, 22.2 and 45.5, respectively, in the 3 periods ( p <0.001). In overweight/obese women, the mean FHR was lower ( p =0.02). Following the logistic regression analysis, two variables remained significantly associated with bradycardia: maternal fitness in the 28 (th) week of pregnancy (protective effect) and maternal weight (increased risk). Conclusion In healthy fetuses, physical exercise proved to be safe, since, although FHR and AFM decreased during treadmill walking, an increase in SVT and LTV was observed419531538CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DA PARAÍBA - FAPESQUniversal 480761/2008-6PPSUS2009Determinar o efeito da caminhada em esteira sobre a frequencia cardiaca materna (FCM) e parametros cardiotocograficos (batimentos cardiofetais basais [BCFs], movimentos ativos fetais [MAFs], numero de aceleracoes e desaceleracoes e variabilidade de curta [STV] e longa [LTV] duracAo da frequencia cardiaca fetal) em gestantes na 36 (a) semana. Metodos Foi realizado um ensaio clinico nAo randomizado e aberto com 88 gestantes saudaveis submetidas a caminhada de moderada intensidade na esteira e a cardiotocografia computadoriza em 3 momentos de 20 minutos (antes, durante e apos a caminhada). Resultados A media dos BCFs diminuiu durante a caminhada, retornando a niveis previos (antes: 137 bpm; durante: 98 bpm; apos: 140 bpm; p <0,001), com bradicardia ocorrendo em 56% dos fetos nos primeiros 10 minutos do exercicio, e em 47% apos 20 minutos. A bradicardia fetal nAo foi observada em outros momentos (antes ou depois). As medias da STV e da LTV foram 7,9, 17,0 e 8,0 milissegundos ( p <0,001) e 7,6, 10,7 e 7,6 bpm ( p =0,002) antes, durante e apos a caminhada, respectivamente. A media dos numeros dos MAFs em 1 hora foi 29,9, 22,2 e 45,5, respectivamente, nos tres momentos ( p <0,001). Nas mulheres com sobrepeso/obesidade, a media da FCM foi menor ( p =0,02). Apos a analise de regressAo logistica, duas variaveis permaneceram significativamente associadas a bradicardia: aptidAo maternal na 28 (a) semana de gravidez (efeito protetor) e peso materno (aumento do risco). ConclusAo Em fetos saudaveis, o exercicio fisico mostrou-se seguro, uma vez que, embora os BCFs e os MAFs diminuam durante a caminhada na esteira, foi observado um aumento da SVT e da LT

    School environment associates with lung function and autonomic nervous system activity in children : a cross-sectional study

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    Children are in contact with local environments, which may affect respiratory symptoms and allergic sensitization. We aimed to assess the effect of the environment and the walkability surrounding schools on lung function, airway inflammation and autonomic nervous system activity. Data on 701 children from 20 primary schools were analysed. Lung function, airway inflammation and pH from exhaled breath condensate were measured. Pupillometry was performed to evaluate autonomic activity. Land use composition and walkability index were quantified within a 500 m buffer zone around schools. The proportion of effects explained by the school environment was measured by mixed-effect models. We found that green school areas tended to be associated with higher lung volumes (FVC, FEV1 and FEF25-75%) compared with built areas. FVC was significantly lower in-built than in green areas. After adjustment, the school environment explained 23%, 34% and 99.9% of the school effect on FVC, FEV1, and FEF25-75%, respectively. The walkability of school neighbourhoods was negatively associated with both pupil constriction amplitude and redilatation time, explaining -16% to 18% of parasympathetic and 8% to 29% of sympathetic activity. Our findings suggest that the environment surrounding schools has an effect on the lung function of its students. This effect may be partially mediated by the autonomic nervous system.Peer reviewe

    Tumorações remissivas múltiplas: a evolução de um câncer de ovário

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    RESUMO: É descrita evolução de um caso de câncer de ovário e suas tumorações remissivas múltiplas, enumerando durante 13 anos os diagnósticos diferenciados. Aos 45 a.i. paciente apresentava um quadro aumento em ovário direito detectado em Ultrassonografia (USG) abdominal, tendo como diagnostico  tumor “borderline” do ovário, realizando ooferectomia total direita. Oito anos após o ocorrido foram detectadas intrabdominalmente focos carcinomatosos múltiplos em todos os quadrantes, recebendo diagnóstico de linfoadenomegalia em região ilíaca esquerda, e mais tardiamente, positivo para metástases pélvicas e diafragmáticas. Enfatiza-se que o câncer de ovário representar um importante fator de morbi-mortalidade entre as mulheres e seu rastreio por exames de imagem permanece imprescindível para auxiliar no reconhecimento precoce e tratamento com melhores prognósticos.Palavras-chave:Neoplasia. Ginecologia. Metástas

    Access to dental services and related factors: a home-based population study

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    Objetivou-se identificar fatores associados à falta de acesso aos serviços odontológicos. Estudo transversal, amostra complexa probabilística por conglomerados em dois estágios de 857 participantes, com mais de 18 anos em um município de grande porte populacional. Foram feitas análises múltiplas através da regressão logística e multivariada em árvores de decisão. Considerou-se como variável dependente o acesso aos serviços odontológicos. Identificou-se que 10,3% não obtiveram acesso. Nas análises múltipla e multivariada constataram-se associação com a idade, na regressão logística constatou-se maior chance de falta de acesso a cada ano de idade incrementado, entre aqueles com menor renda per capita e entre os que classificaram a aparência dos dentes e gengivas como “regular/ruim/péssima”. A falta de acesso aos serviços odontológicos é maior entre os mais vulneráveis socialmente. Há necessidade de incremento na alocação de recursos públicos que promovam educação em saúde e gere conhecimento sobre como acessar os serviços quando necessitar, tendo em foco os cuidados odontológicos como um direito humano e que possibilitem que não ocorra a falta de acesso à medida que os usuários envelhecem ou entre os com baixa renda e também os insatisfeitos com a aparência bucal24310211032The scope of this study was to identify factors associated with lack of access to dental services. It involved a cross-sectional study and a probabilistic complex sample by conglomerates in two stages with 857 participants over 18 years of age in a large city. Multiple analyses by means of logistic and multivariate regression in decision trees were made. The lack of access to dental services was considered a dependent variable. It was identified that 10.3% did not have access. In the multiple and multivariate analyses an association with age was verified and in the logistic regression a greater possibility of lack of access was found for each year of increased age, among those with the lowest per capita income and those who ranked appearance of teeth and gums as “fair/poor/very poor.” The lack of access to dental services was greater among the most socially vulnerable. There is a pressing need to increase the allocation of public resources to promote health education and provide knowledge about how to access services when they are needed, focusing on dental care as a human right and ensuring that lack of access does not occur as users get older or among those with low income and also those dissatisfied with their oral appearanc
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