204 research outputs found

    Morphological and Functional Aspects of Cytoskeleton of Trypanosomatids

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    Trypanosomatidae are protozoans that include monogenetic parasites, such as the Blastocrithidia and Herpetomonas genera, as well as digenetic parasites, such as the Trypanosoma and Leishmania genera. Their life cycles alternate between insect vectors and mammalian hosts. The parasite’s life cycle involves symmetrical division and different transitional developmental stages. In trypanosomatids, the cytoskeleton is composed of subpellicular microtubules organized in a highly ordered array of stable microtubules located beneath the plasma membrane, the paraflagellar rod, which is a lattice-like structure attached alongside the flagellar axoneme and a cytostome-cytopharynx. The complex life cycle, the extremely precise cytoskeletal organization and the single copy structures present in trypanosomatids provide interesting models for cell biology studies. The introduction of molecular biology, FIB/SEM (focused ion beam scanning electron microscopy) and electron microscopy tomography approaches and classical methods, such as negative staining, chemical fixation and ultrafast cryofixation have led to the determination of the three-dimensional (3D) structural organization of the cells. In this chapter, we highlight the recent findings on Trypanosomatidae cytoskeleton emphasizing their structural organization and the functional role of proteins involved in the biogenesis and duplication of cytoskeletal structures. The principal finding of this review is that all approaches listed above enhance our knowledge of trypanosomatids biology showing that cytoskeleton elements are essential to several important events throughout the protozoan life cycle

    Pervasive gaps in Amazonian ecological research

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    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

    Associação entre a ooforectomia bilateral precoce e o desenvolvimento do parkinsonismo e Doença de Parkinson em mulheres na pré-menopausa

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    O parkinsonismo é um distúrbio do sistema nervoso de maior incidência masculina do que feminina, visto que, por mecanismos fisiológicos, o estrogênio possui efeitos neuroprotetores, com funções como aumento da dopamina, um neurotransmissor essencial para o controle das funções motoras. Além disso, previne a formação dos corpúsculos de Lewy e da agregação da α-sinucleína, responsáveis pela progressão da Doença de Parkinson. Por isso, a doença se apresenta diferentemente nas mulheres. A remoção cirúrgica de ambos os ovários em mulheres na pré-menopausa para a prevenção do câncer de ovário parece favorecer o surgimento da doença, tendo em vista a perda da produção do hormônio protetor. Assim, o objetivo do estudo é analisar a associação entre a ooforectomia bilateral precoce e o desenvolvimento de parkinsonismo e Doença de Parkinson em mulheres na pré-menopausa. Trata-se de uma revisão bibliográfica sistemática, do tipo quantitativa, que utilizou as plataformas do PubMed, SciELO e Cochrane Library como bases de dados para seleção dos artigos, todos na língua inglesa. Foram utilizadas literaturas publicadas com recorte temporal de 2017 a 2022. De acordo com as literaturas analisadas, a ooforectomia bilateral precoce em mulheres na pré-menopausa aumenta o risco do desenvolvimento de parkinsonismo. Desse modo, a diminuição dos procedimentos cirúrgicos profiláticos para câncer de ovário nas pacientes com risco médio de malignidade reduziria o risco dessa condição

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    stairs and fire

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    Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

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    A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

    ACAT-related activity assay.

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    <p>The ability of <i>T</i>. <i>cruzi</i> epimastigotes to esterify cholesterol was tested using Sandoz 58-035-58-035 for 16–18 h (A) or Avasimibe for 24 h (B) in different concentrations, followed by addition of BSA-<sup>3</sup>H-palmitate (800,000 DPM; 1 mg/mL) for 24 h. Lipid analysis was performed by TLC; CHOE spots were scraped and the lipid eluted from silica. The lipid-associated radioactivity was measured by liquid scintillation counting. The results are expressed as the mean (±SD) per 1 mg of protein of two independent experiments in duplicate, and analysed by one-way ANOVA followed by the Bonferroni test (*<i>P</i><0.05).</p
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