66 research outputs found

    Chemical constituents of the underground stem bark of Duguetia furfuracea (Annonaceae)

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    In the present investigation the underground parts of Duguetia furfuracea (Annonaceae) were used to conduct a phytochemical study that included the brine shrimp (Artemia salina) lethality bioassay. The substances (-)-duguetine beta-N-oxide, (-)-duguetine, dicentrinone, (-)-N-methyltetrahydropalmatine, and (+)-N-methylglaucine were isolated from the alkaloid extract of the bark of the underground stem, and the ureide allantoin was also isolated by precipitation from the ethanol extract of the wood of the underground stem. A fresh volatile oil and a nonpolar extract were also obtained from the underground stem bark. The substances 2,4,5-trimethoxystyrene, a-gurjunene, aromadendrene, bicyclogermacrene, (E)-methylisoeugenol, and alpha-asarone were isolated from the fresh volatile oil and polycarpol, beta-caryophyllene oxide, 2,4,5-trimethoxystyrene, a-asarone, and asaraldehyde were obtained from the petroleum ether extract. The present study describes for the first time the alkaloid (-)-duguetine beta-N-oxide and the occurrence of (-)-N-methyltetrahydropalmatine and (+)-N-methylglaucine in the family Annonaceae. All extracts were active in the brine shrimp lethality bioassay

    Fast relational learning using bottom clause propositionalization with artificial neural networks

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    Relational learning can be described as the task of learning first-order logic rules from examples. It has enabled a number of new machine learning applications, e.g. graph mining and link analysis. Inductive Logic Programming (ILP) performs relational learning either directly by manipulating first-order rules or through propositionalization, which translates the relational task into an attribute-value learning task by representing subsets of relations as features. In this paper, we introduce a fast method and system for relational learning based on a novel propositionalization called Bottom Clause Propositionalization (BCP). Bottom clauses are boundaries in the hypothesis search space used by ILP systems Progol and Aleph. Bottom clauses carry semantic meaning and can be mapped directly onto numerical vectors, simplifying the feature extraction process. We have integrated BCP with a well-known neural-symbolic system, C-IL2P, to perform learning from numerical vectors. C-IL2P uses background knowledge in the form of propositional logic programs to build a neural network. The integrated system, which we call CILP++, handles first-order logic knowledge and is available for download from Sourceforge. We have evaluated CILP++ on seven ILP datasets, comparing results with Aleph and a well-known propositionalization method, RSD. The results show that CILP++ can achieve accuracy comparable to Aleph, while being generally faster, BCP achieved statistically significant improvement in accuracy in comparison with RSD when running with a neural network, but BCP and RSD perform similarly when running with C4.5. We have also extended CILP++ to include a statistical feature selection method, mRMR, with preliminary results indicating that a reduction of more than 90 % of features can be achieved with a small loss of accuracy

    Evaluation of rK39 rapid diagnostic tests for canine visceral leishmaniasis : longitudinal study and meta-analysis

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    Canine visceral leishmaniasis is a vector-borne disease caused by the intracellular parasite Leishmania infantum. It is an important veterinary disease, and dogs are also the main animal reservoir for human infection. The disease is widespread in the Mediterranean area, and parts of Asia and South and Central America, and is potentially fatal in both dogs and humans unless treated. Diagnosis of canine infections requires serological or molecular tests. Detection of infection in dogs is important prior to treatment, and in epidemiological studies and control programmes, and a sensitive and specific rapid diagnostic test would be very useful. Rapid diagnostic tests (RDTs) have been developed, but their diagnostic performance has been reported to be variable. We evaluated the sensitivity of a RDT based on serological detection of the rK39 antigen in a cohort of naturally infected Brazilian dogs. The sensitivity of the test to detect infection was relatively low, but increased with time since infection and the severity of infection. We then carried out a meta-analysis of published studies of rK39 RDTs, evaluating the sensitivity to detect disease and infection. The results suggest that rK39 RDTs may be useful in a veterinary clinical setting, but the sensitivity to detect infection is too low for operational control programmes

    Os sistemas agroflorestais como alternativa de sustentabilidade em ecossistemas de várzea no Amazonas.

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    Os sistemas agroflorestais (SAFs) representam uma alternativa agroecológica de produção, sob regime sustentável, para os agricultores familiares na várzea dos Rios Solimões/Amazonas, principalmente no que se refere ao manejo florestal, à diversidade de produtos e à geração de renda. Diante disso, o objetivo deste trabalho foi compreender as diferentes formas de apropriação e de manejo dos recursos naturais através dos SAFs, nos subsistemas roça, sítio e lagos, como componente para a sustentabilidade dos agricultores familiares da localidade Costa da Terra Nova, município do Careiro da Várzea, Amazonas. O método empregado foi o Estudo de Caso com aplicação de questionários, entrevistas e observação participante. A produção familiar na Costa da Terra Nova é representada pelos SAFs, constituído pelos os subsistemas: roça quintal e lago, que proporcionam produtos tanto para subsistência quanto para comercialização local, e estabelecendo a agricultura como fundamental atividade na localidade. O principal produto para comercialização é obtido das hortaliças cultivadas na época da vazante no subsistema roça nas comunidades São Francisco e Nossa Senhora da Conceição; e do extrativismo pesqueiro no subsistema lago, na época da cheia, principalmente na comunidade São José. A criação de animal se dá no subsistema sítio e é apenas para subsistência, sendo as aves e os suínos os principais animais domésticos criados nas três comunidades. Portanto os SAFs tradicionais, constituídos pelos subsistemas, roça, sitio e lago, são responsáveis pela sustentabilidade socioeconômica da localidade pesquisada, servindo, como alternativa agrícola melhor adaptada às condições locais das áreas de várzea na Amazônia

    Congenital Zika syndrome is associated with maternal protein malnutrition

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    Zika virus (ZIKV) infection during pregnancy is associated with a spectrum of developmental impairments known as congenital Zika syndrome (CZS). The prevalence of this syndrome varies across ZIKV endemic regions, suggesting that its occurrence could depend on cofactors. Here, we evaluate the relevance of protein malnutrition for the emergence of CZS. Epidemiological data from the ZIKV outbreak in the Americas suggest a relationship between undernutrition and cases of microcephaly. To experimentally examine this relationship, we use immunocompetent pregnant mice, which were subjected to protein malnutrition and infected with a Brazilian ZIKV strain. We found that the combination of protein restriction and ZIKV infection leads to severe alterations of placental structure and embryonic body growth, with offspring displaying a reduction in neurogenesis and postnatal brain size. RNA-seq analysis reveals gene expression deregulation required for brain development in infected low-protein progeny. These results suggest that maternal protein malnutrition increases susceptibility to CZS.Fil: Barbeito Andrés, Jimena. Universidade Federal do Rio de Janeiro; Brasil. Universidad Nacional Arturo Jauretche. Unidad Ejecutora de Estudios en Neurociencias y Sistemas Complejos. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic. Unidad Ejecutora de Estudios en Neurociencias y Sistemas Complejos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Unidad Ejecutora de Estudios en Neurociencias y Sistemas Complejos; ArgentinaFil: Pezzuto, Paula. Universidade Federal do Rio de Janeiro; BrasilFil: Higa, Luiza. Universidade Federal do Rio de Janeiro; BrasilFil: Dias, André Alves. Universidade Federal do Rio de Janeiro; BrasilFil: Vasconcelos, Janaina. Universidade Federal do Pará; BrasilFil: Santos, T. M. P.. Universidade Federal do Rio de Janeiro; BrasilFil: Ferreira, Jéssica. Universidade Federal do Rio de Janeiro; BrasilFil: Ferreira, R. O.. Universidade Federal do Rio de Janeiro; BrasilFil: Dutra, F. F.. Universidade Federal do Rio de Janeiro; BrasilFil: Rossi, A. D.. Universidade Federal do Rio de Janeiro; BrasilFil: Barbosa, R. V.. Universidade Federal Do Rio de Janeiro. Centro Nacional de Biologia Estrutural E Bioimagem.; BrasilFil: Amorim, C. K. N.. Evandro Chagas Institute; BrasilFil: de Souza, M. P. C.. Evandro Chagas Institute; BrasilFil: Chimelli, L.. Instituto Estadual do Cérebro Paulo Niemeyer ; BrasilFil: Aguiar, R. S.. Universidade Federal do Rio de Janeiro; BrasilFil: Gonzalez, Paula Natalia. Universidad Nacional Arturo Jauretche. Unidad Ejecutora de Estudios en Neurociencias y Sistemas Complejos. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic. Unidad Ejecutora de Estudios en Neurociencias y Sistemas Complejos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Unidad Ejecutora de Estudios en Neurociencias y Sistemas Complejos; ArgentinaFil: Lara, F. A.. Oswaldo Cruz Institute; BrasilFil: Castro, M.C.. Harvard University. Harvard School of Public Health; Estados UnidosFil: Molnár, Z.. University of Oxford; Reino UnidoFil: Lopes, R. T.. Universidade Federal do Rio de Janeiro; BrasilFil: Bozza, M. T.. Universidade Federal do Rio de Janeiro; BrasilFil: Vianez, J. L. S. G.. Evandro Chagas Institute; BrasilFil: Barbeito, Claudio Gustavo. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Cuervo, P.. Oswaldo Cruz Institute; BrasilFil: Bellio, M.. Universidade Federal do Rio de Janeiro; BrasilFil: Tanuri, A.. Universidade Federal do Rio de Janeiro; BrasilFil: Garcez, P. P.. Universidade Federal do Rio de Janeiro; Brasi

    Antibody response to sand fly saliva is a marker of transmission intensity but not disease progression in dogs naturally infected with Leishmania infantum

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    BACKGROUND: Antibody responses to sand fly saliva have been suggested to be a useful marker of exposure to sand fly bites and Leishmania infection and a potential tool to monitor the effectiveness of entomological interventions. Exposure to sand fly bites before infection has also been suggested to modulate the severity of the infection. Here, we test these hypotheses by quantifying the anti-saliva IgG response in a cohort study of dogs exposed to natural infection with Leishmania infantum in Brazil. METHODS: IgG responses to crude salivary antigens of the sand fly Lutzomyia longipalpis were measured by ELISA in longitudinal serum samples from 47 previously unexposed sentinel dogs and 11 initially uninfected resident dogs for up to 2 years. Antibody responses were compared to the intensity of transmission, assessed by variation in the incidence of infection between seasons and between dogs. Antibody responses before patent infection were then compared with the severity of infection, assessed using tissue parasite loads and clinical symptoms. RESULTS: Previously unexposed dogs acquired anti-saliva antibody responses within 2 months, and the rate of acquisition increased with the intensity of seasonal transmission. Over the following 2 years, antibody responses varied with seasonal transmission and sand fly numbers, declining rapidly in periods of low transmission. Antibody responses varied greatly between dogs and correlated with the intensity of transmission experienced by individual dogs, measured by the number of days in the field before patent infection. After infection, anti-saliva antibody responses were positively correlated with anti-parasite antibody responses. However, there was no evidence that the degree of exposure to sand fly bites before infection affected the severity of the infection. CONCLUSIONS: Anti-saliva antibody responses are a marker of current transmission intensity in dogs exposed to natural infection with Leishmania infantum, but are not associated with the outcome of infection

    Molecular and cellular mechanisms underlying the evolution of form and function in the amniote jaw.

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    The amniote jaw complex is a remarkable amalgamation of derivatives from distinct embryonic cell lineages. During development, the cells in these lineages experience concerted movements, migrations, and signaling interactions that take them from their initial origins to their final destinations and imbue their derivatives with aspects of form including their axial orientation, anatomical identity, size, and shape. Perturbations along the way can produce defects and disease, but also generate the variation necessary for jaw evolution and adaptation. We focus on molecular and cellular mechanisms that regulate form in the amniote jaw complex, and that enable structural and functional integration. Special emphasis is placed on the role of cranial neural crest mesenchyme (NCM) during the species-specific patterning of bone, cartilage, tendon, muscle, and other jaw tissues. We also address the effects of biomechanical forces during jaw development and discuss ways in which certain molecular and cellular responses add adaptive and evolutionary plasticity to jaw morphology. Overall, we highlight how variation in molecular and cellular programs can promote the phenomenal diversity and functional morphology achieved during amniote jaw evolution or lead to the range of jaw defects and disease that affect the human condition

    Control of Visceral Leishmaniasis in Latin America—A Systematic Review

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    Visceral leishmaniasis is a vector-borne disease characterized by fever, spleen and liver enlargement, and low blood cell counts. In the Americas VL is zoonotic, with domestic dogs as main animal reservoirs, and is caused by the intracellular parasite Leishmania infantum (syn. Leishmania chagasi). Humans acquire the infection through the bite of an infected sand fly. The disease is potentially lethal if untreated. VL is reported from Mexico to Argentina, with recent trends showing a rapid spread in Brazil. Control measures directed against the canine reservoir and insect vectors have been unsuccessful, and early detection and treatment of human cases remains as the most important strategy to reduce case fatality. Well-designed studies evaluating diagnosis, treatment, and prevention/control interventions are scarce. The available scientific evidence reasonably supports the use of rapid diagnostic tests for the diagnosis of human disease. Properly designed randomized controlled trials following good clinical practices are needed to inform drug policy. Routine control strategies against the canine reservoirs and insect vectors are based on weak and conflicting evidence, and vector control strategies and vaccine development should constitute research priorities
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