Técnicas de separação biomimética em microfluídica

A separação e a identificação de células são essenciais em várias aplicações biomédicas, incluindo a biologia celular e os métodos de diagnóstico e terapêuticos. O sangue é um fluido não-Newtoniano contendo inúmeras informações preciosas sobre o estado fisiológico e patológico do corpo humano. No entanto, devido à sua complexidade, existem actualmente poucos métodos de análise precisos. A maioria das técnicas convencionais usadas na separação e contagem de células são dispendiosas e normalmente é necessário usar agentes externos adicionais para identificar as células. As técnicas biomiméticas de separação em microfluídica usam fenómenos microfluídicos, que ocorrem à microescala, para realizar a separação de determinadas células sanguíneas. Estes fenómenos incluem a separação do plasma, a camada livre de células (CLC), a migração dos glóbulos brancos (GBs), também designados por leucócitos, e a lei da bifurcação. Recentemente, vários investigadores têm replicado estes efeitos, que acontecem em ambientes in vivo, em sistemas microfluídicos, ou seja, em ambientes in vitro. Nos microcanais, os glóbulos vermelhos (GVs), devido à sua deformabilidade e ao gradiente de velocidades (às forças de sustentação), tendem a concentrar-se na zona central dos microcanais, enquanto os GBs e os GVs rígidos (tal como, os GVs infectados com malária) tendem a migrar para a CLC que se forma nas zonas próximas das paredes. A lei da bifurcação estabelece, relativamente ao comportamento dos GVs, que em microcanais com bifurcações eles tendem a escolher o microcanal de secção maior.Os autores agradecem à FCT, COMPETE, QREN e União Europeia (FEDER) pelo financiamento através dos seguintes projetos: PTDC/SAU-BEB/105650/2008, PTDC/SAU-BEB/108728/2008, PTDC/EME-MFE/099109/2008 ePTDC/SAU-ENB/116929/2010

Mesoproterozoic intraplate magmatic ‘barcode’ record of the Angola portion of the Congo Craton: Newly dated magmatic events at 1505 and 1110 Ma and implications for Nuna (Columbia) supercontinent reconstructions

In the Angola portion of the Congo Craton, the only Proterozoic large igneous province (LIP) dated prior to this study was the 1380–1370 Ma (Kunene Intrusive Complex and related units). U–Pb TIMS ages on baddeleyite from dolerite sills and gabbro-noritic dykes, has revealed two additional Mesoproterozoic intraplate events: at ca. 1505 and ca. 1110 Ma, that are each proposed to be part of the plumbing system for LIPs. The identification of these three Mesoproterozoic magmatic events (ca. 1505, 1380, and 1110 Ma) represent an initial magmatic ‘barcode’ for this portion of Congo Craton (and formerly connected São Francisco Craton), which can be compared with the magmatic ‘barcode’ record of other blocks to identify former nearest neighbors in the Precambrian supercontinent Nuna (also known as Columbia).Specifically, a 1502 ± 5 Ma U–Pb TIMS baddeleyite age has been obtained for the prominent Humpata dolerite sill which is part of a wider sill province in SW Angola portion of the Congo Craton. The combined presence of both 1505 Ma and 1380 Ma magmatism in the Congo–São Francisco reconstructed craton is a match with similar ages published for two intraplate magmatic provinces in northern Siberia and suggests a nearest-neighbor relationship in the supercontinent Nuna in which northern Siberia is juxtaposed adjacent to the western São Francisco portion of the reconstructed São Francisco–Congo Craton.In addition, a precise U–Pb TIMS baddeleyite age of 1110 ± 2.5 Ma was obtained for a prominent NNW–NNE trending gabbro-noritic (GN) dyke swarm in southeastern Angola, but this age is currently unknown in Siberia suggesting that the breakup of Congo–São Francisco Craton from Siberia happened earlier, perhaps in association with the 1380 Ma event. This 1110 Ma age is however, a precise match with that of the Umkondo large igneous province (LIP) of the Kalahari Craton, and also with mafic intraplate magmatism on other blocks such as the Bundelkhand Craton (India) and the Amazonian Craton. We provisionally consider these three cratons to have been nearest neighbors to the Congo–São Francisco Craton at this time and to have shared this 1110 Ma magmatic event as a LIP node. There is also an age match with the early part of the Keweenawan event (in the interior of the Laurentia); however, on previously discussed paleomagnetic grounds the Keweenawan event is likely to have been distant and unrelated (and on the other side of the Grenville orogen)

Occurrence of non-toxic bioemulsifiers during polyhydroxyalkanoate production by Pseudomonas strains valorizing crude glycerol by-product

While screening for polyhydroxyalkanoate (PHA) producing strains, using glycerol rich byproduct as carbon source, it was observed that extracellular polymers were also secreted into the culture broth. The scope of this study was to characterize both intracellular and extracellular polymers, produced by Pseudomonas putida NRRL B 14875 and Pseudomonas chlororaphis DSM 50083, mostly focusing on those novel extracellular polymers. It was found that they fall into the class of bioemulsifiers (BE), as they showed excellent emulsion stability against different hydrocarbons/oils at various pH conditions, temperature and salinity concentrations. Cytotoxicity tests revealed that BE produced by P. chlororaphis inhibited the growth of highly pigmented human melanoma cells (MNT-1) by 50% at concentrations between 150-200 μg/mL, while no effect was observed on normal skin primary keratinocytes and melanocytes. This is the first study reporting mcl-PHA production by P. putida NRRL B-14785 and bioemulsifier production from both P. putida and P. chlororaphis strains

In vitro efficacy of Metarhizium anisopliae sensu lato against unfed Amblyomma parvum (Acari: Ixodidae).

Amblyomma parvum Aragão (Acari: Ixodidae) is a tick species found with wide distribution in the Neotropical region. Even though it is a wildlife-related tick, it is also a frequent parasite of domestic animals, is aggressive to human beings and may harbor pathogenic microorganisms. Therefore, it is a target species for control on domestic animals, particularly those at the rural?wildlife interface. Herein, the efficacy of two isolates (E9 and IBCB 425) of an entomopathogenic fungus, Metarhizium anisopliae sensu lato, already evaluated for ticks that parasitize domestic animals, was tested against unfed A. parvum adults. Both isolates displayed high acaricidal efficacy after immersion in fungal conidial suspensions for 5 min. Isolate E9 killed all ticks by the 7th day post-treatment, and isolate IBCB 425 did so by the 11th day. Tick mortality of 80 and 90% was achieved as early as the 3rd and 4th days, respectively, with both treatments. Thus, if a commercial M. anisopliae s.l. acaricide against domestic animal ticks is developed, it would also be effective against A. parvum

Professional activities of parents of High School students applicants to Health Sciences Courses

Modelo do estudo: Estudo baseado em coleta de informações por meio de Questionário Estruturado. Objetivo do estudo: Verificar indicadores da situação econômica e cultural das famílias de alunos do segundo grau que pleiteiam o ingresso em cursos destinados a formar profissionais da saúde. Metodologia: Questionários auto-administrados foram respondidos por 256 estudantes do segundo grau, visitantes de Feira das Profissões da USP (FPUSP-interior). Esses questionários continham perguntas relativas ao tipo de escola que frequentavam e as atividades laborais de seus genitores. Os 108 estudantes de Escolas Públicas constituíram o Grupo 1 e os 148 alunos de Escolas Particulares formaram o Grupo 2. Resultados: A atividade profissional paterna mais frequente no Grupo 1 foi a de “Técnico Manual”(42,15%) e no Grupo 2 a de “Profissional de Nível Universitário” (24,11%). O maior grupo de mães do Grupo 1 foi composto por “Donas de Casa” (22,33%) seguido pelo das que exerciam “Outras Profissões Manuais”( 21,36%). No Grupo 2 a categoria mais frequente para as mães foi “Profissionais de Nível Universitário” (23,18%) seguida por “Professores e Diretores de Escolas” (19,56%). Cinco participantes do Grupo 1 e 27 do Grupo 2 eram filhos de Profissionais da Saúde. Conclusões: Apesar das diferenças das atividades laborais predominantes em cada um dos grupos estudados, os resultados confirmam que aspiração de se tornar um Profissional da Saúde independe da formação ou das profissões dos pais.Study design: Study based on collection of information by means of a Structured Questionnaire. Objective of the study: To determine indicators of the economic and cultural situation of the families of high school students who intend to enroll in courses for the formation of health professionals. Methodology: Self-report questionnaires were answered by 256 high school students who were visiting the Professions Fair of USP (FPUSP- inland). The questionnaires contained questions about the type of school the students frequented and the work activities of their parents. Group 1 consisted of 108 Public School students and Group 2 consisted of 148 Private School students. Results: The most frequent paternal professional activity was “Manual Technician” (42.15%) for Group 1 and “University Level Professional” (24.11%) for Group 2 . The largest group of mothers in Group 1 consisted of “Housewives” (22.33%), followed by the group of mothers who had “Other Manual Professions” (21.36%). In Group 2, the most frequent category for the mothers was “University Level Professional” (23.18%), followed by “Teachers and Directors of Schools” (19.56%). Five participants in Group 1 and 27 in Group 2 were children of Health Professionals. Conclusions: Despite the differences in the work activities predominating in each group studied, the results confirm the ambition to become a Health Professional regardless of the training or profession of the parent

In Vitro and In Vivo High-Throughput Assays for the Testing of Anti-Trypanosoma cruzi Compounds

The treatment of Trypanosoma cruzi infection (the cause of human Chagas disease) remains a significant challenge. Only two drugs, both with substantial toxicity, are available and the efficacy of these dugs is often questioned – in many cases due to the limitations of the methods for assessing efficacy rather than to true lack of efficacy. For these reasons relatively few individuals infected with T. cruzi actually have their infections treated. In this study, we report on innovative methods that will facilitate the discovery of new compounds for the treatment of T. cruzi infection and Chagas disease. Utilizing fluorescent and bioluminescent parasite lines, we have developed in vitro tests that are reproducible and facile and can be scaled for high-throughput screening of large compound libraries. We also validate an in vivo screening test that monitors parasite replication at the site of infection and determines the effectiveness of drug treatment in less than two weeks. More importantly, results in this rapid in vivo test show strong correlations with those obtained in long-term (e.g. 40 day or more) treatment assays. The results of this study remove one of the obstacles for identification of effective and safe compounds to treat Chagas disease

The biological in vitro effect and selectivity of aromatic dicationic compounds on Trypanosoma cruzi

Trypanosoma cruzi is a parasite that causes Chagas disease, which affects millions of individuals in endemic areas of Latin America. One hundred years after the discovery of Chagas disease, it is still considered a neglected illness because the available drugs are unsatisfactory. Aromatic compounds represent an important class of DNA minor groove-binding ligands that exhibit potent antimicrobial activity. This study focused on the in vitro activity of 10 aromatic dicationic compounds against bloodstream trypomastigotes and intracellular forms of T. cruzi. Our data demonstrated that these compounds display trypanocidal effects against both forms of the parasite and that seven out of the 10 compounds presented higher anti-parasitic activity against intracellular parasites compared with the bloodstream forms. Additional assays to determine the potential toxicity to mammalian cells showed that the majority of the dicationic compounds did not considerably decrease cellular viability. Fluorescent microscopy analysis demonstrated that although all compounds were localised to a greater extent within the kinetoplast than the nucleus, no correlation could be found between compound activity and kDNA accumulation. The present results stimulate further investigations of this class of compounds for the rational design of new chemotherapeutic agents for Chagas disease