Situação de estudo: contextualização e reflexão de uma práctica docente em química

Este artigo tem por objetivo discutir e contextualizar novas organizações curriculares através da inserção de Situações de Estudo (SE) com foco na Educação Ambiental (EA). Convida os educadores a fazerem uma reflexão epistemológica sobre o processo formativo da docência relacionada à organização do conhecimento escolar com as questões socioambientais. Os dados construídos foram analisados a partir da mediação docente de uma professora da Educação Básica no contexto das aulas de química com base na prática da SE, que de início precisou alavancar a dialogicidade “adormecida” através das interações entre os sujeitos, anteriores à EA. A prática mostrou-se eficiente devido ruptura linear frente ao contexto escolar atual, de função social e cultural ao permitir a (re)ligação dos saberes escolares.This article aims at discussing and at contextualizing the new curricular organizations through de insertion of Study Situation (SS) with the focus on Environmental Education. This research invites teachers to make an epistemological reflection about the formative process of teachers related to the organization of the school knowledge with the socio environmental questions. The dada constructed were analyzed trough the teachers mediation of a Teacher of Basic Education in the context of Chemistry classes based on the practice of SS, that the beginning needed to leveraging the ‘dormant’ dialogicality trough the interactions between the subjects, previous the EE. This practice shows being efficient due to the linear rupture related to the nowadays schoo

Microbial stimulation fully differentiates monocytes to DC-SIGN/CD209 + dendritic cells for immune T cell areas

Dendritic cells (DCs), critical antigen-presenting cells for immune control, normally derive from bone marrow precursors distinct from monocytes. It is not yet established if the large reservoir of monocytes can develop into cells with critical features of DCs in vivo. We now show that fully differentiated monocyte-derived DCs (Mo-DCs) develop in mice and DC-SIGN/CD209a marks the cells. Mo-DCs are recruited from blood monocytes into lymph nodes by lipopolysaccharide and live or dead gram-negative bacteria. Mobilization requires TLR4 and its CD14 coreceptor and Trif. When tested for antigen-presenting function, Mo-DCs are as active as classical DCs, including cross-presentation of proteins and live gram-negative bacteria on MHC I in vivo. Fully differentiated Mo-DCs acquire DC morphology and localize to T cell areas via L-selectin and CCR7. Thus the blood monocyte reservoir becomes the dominant presenting cell in response to select microbes, yielding DC-SIGN + cells with critical functions of DCs

Targeting Leishmania major Antigens to Dendritic Cells In Vivo Induces Protective Immunity

Efficient vaccination against the parasite Leishmania major, the causative agent of human cutaneous leishmaniasis, requires development of type 1 T-helper (Th1) CD4+ T cell immunity. Because of their unique capacity to initiate and modulate immune responses, dendritic cells (DCs) are attractive targets for development of novel vaccines. In this study, for the first time, we investigated the capacity of a DC-targeted vaccine to induce protective responses against L. major. To this end, we genetically engineered the N-terminal portion of the stress-inducible 1 protein of L. major (LmSTI1a) into anti-DEC205/CD205 (DEC) monoclonal antibody (mAb) and thereby delivered the conjugated protein to DEC+ DCs in situ in the intact animal. Delivery of LmSTI1a to adjuvant-matured DCs increased the frequency of antigen-specific CD4+ T cells producing IFN-γ+, IL-2+, and TNF-α+ in two different strains of mice (C57BL/6 and Balb/c), while such responses were not observed with the same doses of a control Ig-LmSTI1a mAb without receptor affinity or with non-targeted LmSTI1a protein. Using a peptide library for LmSTI1a, we identified at least two distinct CD4+ T cell mimetopes in each MHC class II haplotype, consistent with the induction of broad immunity. When we compared T cell immune responses generated after targeting DCs with LmSTI1a or other L. major antigens, including LACK (Leishmania receptor for activated C kinase) and LeIF (Leishmania eukaryotic ribosomal elongation and initiation factor 4a), we found that LmSTI1a was superior for generation of IFN-γ-producing CD4+ T cells, which correlated with higher protection of susceptible Balb/c mice to a challenge with L. major. For the first time, this study demonstrates the potential of a DC-targeted vaccine as a novel approach for cutaneous leishmaniasis, an increasing public health concern that has no currently available effective treatment

Generation and large-scale expansion of highly functional hPSC-derived hepatocytes for Cellular therapies and bioengineered livers: the unknown role of human microbiome

Los hepatocitos diferenciados a partir de células madre pluripotentes inducidas humanas (hiPSC), también conocidos como hepatocyte-like cells (HLC), proporcionan una cantidad sin precedentes de posibilidades para el desarrollo de terapias celulares y, con ello, el tratamiento de una gran variedad de enfermedades hepáticas. Sin embargo, más de quince años de investigación en este campo han sido insuficientes para obtener una terapia médica avanzada a base de HLC. Los fenotipos inmaduros que presentan estas células, la falta de protocolos fiables y reproducibles para su producción a gran escala, así como la incertidumbre con respecto a su capacidad para injertarse en andamios (o scaffolds), tanto in vitro como in vivo, son algunas de las razones que dificultan su aplicación clínica. Por lo tanto, el objetivo de esta tesis ha sido el desarrollo de estrategias eficientes para generar HLC maduras y funcionales en cantidades clínicamente relevantes para su uso en terapia celular y medicina regenerativa. Para ello, se ha desarrollado un método integrado que combina plataformas de fabricación avanzada con estrategias inspiradas en procesos naturales, estudiando el efecto del microbioma intestinal humano en la maduración y la preservación de las funciones de las HLC.Recapitular in vitro el proceso de maduración fisiológica del hígado supone un gran reto, ya que dura aproximadamente dos años desde el nacimiento e implica la inducción de una amplia gama de vías metabólicas y de desintoxicación. Investigaciones recientes sobre el desarrollo del hígado han revelado que la maduración y el desarrollo de la función hepática podrían estar altamente asociados con el establecimiento y la diversificación del microbioma intestinal.En el Capítulo 1, discutimos las moléculas microbianas y los mecanismos moleculares que constituyen esta interacción.En el Capítulo 2, investigamos los efectos del secretoma de la microbiota intestinal sobre la funcionalidad (o maduración) de las hPSC-HLC mediante el tratamiento de estas células, generadas utilizando diferentes estrategias en 2D o 3D, con un secretoma microbiano formulado in vitro en forma de medio condicionado. Nuestros resultados muestran que las HLC expuestas al medio condicionado presentan una mayor expresión de marcadores hepáticos (p.ej. HNF4A, CYP1B1, -3A4, -2C9, -2D6,16-2E1, CPS1, PPARA, TLR1, -2, -5, -6, etc.); conservan la actividad basal de CYP3A4 y/o mostraban metabolismo inducible CYP3A4; mejoran la expresión de ALB; y aumentan la secreción de las proteínas hepáticas plasmáticas ALB y A1AT, en comparación con HLC no tratadas con el medio condicionado.Dado que las terapias celulares requieren una alta producción celular, en los Capítulos 3 y 4 desarrollamos bioprocesos escalables para la producción de HLC en forma de agregados celulares tridimensionales.En el Capítulo 3, implementamos una estrategia integrada para la producción a gran escala de hiPSC‐HLC, que combina la expansión y diferenciación en 3D de las hiPSC usando biorreactores de tanque agitado en modo de perfusión. Mediante este protocolo, las hiPSC son capaces de crecer en agregados 3D y las HLC resultantes expresan marcadores hepáticos típicos y exhiben características funcionales de los hepatocitos, incluyendo el almacenamiento de glucógeno y la capacidad de metabolización de fármacos. Además, la incorporación de un sensor de capacitancia en el sistema del biorreactor nos ha permitido demostrar por primera vez el potencial de la espectroscopia dieléctrica para monitorizar la expansión y diferenciación de hiPSC en los biorreactores de tanque agitado. Los resultados que obtuvimos mostraron una buena correlación entre la permitividad celular medida on-line y el biovolumen de los agregados medido por métodos estándar off-line.Con el objetivo de mejorar la expansión celular y el rendimiento de la diferenciación, en el Capítulo 4 optimizamos el bioproceso al mantener la concentración de oxígeno disuelto en niveles bajos (4% O2) durante la fase de especificación hepática. Hemos validado esta optimización para dos líneas celulares de hiPSC mejorando el rendimiento de producción de HLC (hasta 3.2x106 células/mL) y la eficiencia de diferenciación (> 80% células Albumina+) en comparación con condiciones no controladas (0.6×106 células/mL). Un análisis transcriptómico detallado de las HLC en diferentes etapas de maduración muestra que las hiPSC-HLC maduras difieren aproximadamente un 35% en su transcriptoma completo con respecto a hiPSC-HCL inmaduras. Estas diferencias incluyen vías relacionadas con el injerto celular, teniendo implicaciones en la capacidad celular para injertarse en andamios, ya que solo las HLC maduras pueden adherirse, proliferar y mantener su funcionalidad después de 14 días de cultivo.17Por último, en el Capítulo 5, presentamos una discusión general de los logros y conclusiones principales del trabajo realizado y delineamos futuras perspectivas a investigar.En conclusión, este estudio representa un importante primer paso hacia la generación de HLC derivadas de hiPSC más maduras y funcionales que, esperamos, harán que las terapias con células madre hepáticas sean una realidad tangible para los pacientes con enfermedad hepática en etapa terminal. También abre un nuevo cambio de paradigma en la bioingeniería de células madre y lo vincula con un campo inesperado, el microbioma humano.<br /

Identification of a novel human E-Cadherin splice variant andassessment of its effects upon EMT-related events

Epithelial Cadherin (E-cadherin) is involved in calcium-dependent cell-cell adhesion and signal transduction. The E-cadherin decrease/loss is a hallmark of Epithelial to Mesenchymal Transition (EMT), a key event in tumor progression. The underlying molecular mechanisms that trigger E-cadherin loss and consequent EMT have not been completely elucidated. This study reports the identification of a novel human E-cadherin variant mRNA produced by alternative splicing. A bioinformatics evaluation of the novel mRNA sequence and biochemical verifications suggest its regulation by Nonsense-Mediated mRNA Decay (NMD). The novel E-cadherin variant was detected in 29/42 (69%) human tumor cell lines, expressed at variable levels (E-cadherin variant expression relative to the wild type mRNA = 0.05-11.6%). Stable transfection of the novel E-cadherin variant in MCF-7 cells (MCF7Ecadvar) resulted in downregulation of wild type E-cadherin expression (transcript/protein) and EMT-related changes, among them acquisition of a fibroblastic-like cell phenotype, increased expression of Twist, Snail, Zeb1, and Slug transcriptional repressors and decreased expression of ESRP1 and ESRP2 RNA binding proteins. Moreover, loss of cytokeratins and gain of vimentin, N-cadherin and Dysadherin/FXYD5 proteins was observed. Dramatic changes in cell behavior were found in MCF7Ecadvar, as judged by the decreased cell-cell adhesion (Hanging-drop assay), increased cell motility (Wound Healing) and increased cell migration (Transwell) and invasion (Transwell w/Matrigel). Some changes were found in MCF-7 cells incubated with culture medium supplemented with conditioned medium from HEK-293 cells transfected with the E-cadherin variant mRNA. Further characterization of the novel E-cadherin variant will help understanding the molecular basis of tumor progression and improve cancer diagnosis.Fil: Matos, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Lapyckyj, Lara. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Rosso, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Besso, María José. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Mencucci, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Marin Briggiler, Clara Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Giustina, Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Furlong, Laura Ines. Universitat Pompeu Fabra; EspañaFil: Vazquez, Monica Hebe. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

Reações Químicas no Ensino de Química: Compreensões por meio da Experimentação

Esse estudo tem como objetivo refletir a partir da realização de uma proposta didática para o ensino de química, por meio da experimentação, realizada no 2º ano do Ensino Médio, que possibilitou o desenvolvimento e construções acerca do conteúdo de Cinética Química. Tal atividade foi realizada com a regência de classe, em uma escola da rede pública do Rio Grande do Sul. Diante da proposta se percebeu um amplo interesse dos estudantes em aprender por meio da experimentação, tendo em vista que essa propicia uma relação entre teoria e prática, estimulando a compreensão do conhecimento científico e desenvolvendo a criticidade e o protagonismo do sujeito no processo de ensino e aprendizagem. Além disso, destacamos o papel do professor como mediador do processo de desenvolvimento do conhecimento, orientando e estimulando os estudantes na busca por construções significativas da aprendizagem. Nesse sentido, compreendemos que a prática da experimentação aliada a teoria, além de estimular o interesse do sujeito, auxilia no processo de aprendizagem, contribuindo para o conhecimento científico e formação do sujeito com autonomia

O desafio de inserir a experimentação no ensino de ciências e entender a sua função pedagógica

Este trabalho trata do papel da experimentação no ensino de Ciências da Natureza e suas Tecnologias, a partir de um olhar à vivência de uma professora, em busca de entender teoricamente sua prática, na perspectiva da significação dos conceitos na escola. Trata-se de uma delimitação do tempo edo lugar da prática da professora que faz uso de diferentes estratégias de ensino para alavancar interlocuções e entendimentos sobre o “teor de álcool na gasolina”. Articular a experimentação em sala de aula como uma constante instigação dialógica entre saberes teóricos e práticos, com vistas à (re)significar conceitos cotidianos e científicos em contextos inter e extraescolares, foi o desafio enfrentado pela professora; ao refletir sobre dificuldades e possibilidades associadas à inserção da experimentação no ensino escolar. As discussões provocadas tiveram desdobramentos positivos, como atitude de ação-formação-reflexão em que os sujeitos escolares, mais interativos, tornaram-se participativos nas interações/ações em sala de aula

Connecting red cells in a bichromatic Voronoi diagram

Let S be a set of n + m sites, of which n are red and have weight wR, and m are blue and weigh wB. The objective of this paper is to calculate the minimum value of wR such that the union of the red Voronoi cells in the weighted Voronoi diagram of S is a connected set. The problem is solved for the multiplicatively-weighted Voronoi diagram in O((n+m)^2 log(nm)) time and for the additively-weighted Voronoi diagram in O(nmlog(nm)) time

Flt3L-dependence helps define an uncharacterized subset of murine cutaneous dendritic cells

Skin-derived dendritic cells (DC) are potent antigen presenting cells with critical roles in both adaptive immunity and tolerance to self. Skin DC carry antigens and constitutively migrate to the skin draining lymph nodes (LN). In mice, Langerin-CD11b− dermal DC are a low-frequency, heterogeneous, migratory DC subset that traffic to LN (Langerin-CD11b-migDC). Here, we build on the observation that Langerin-CD11b− migDC are Fms-like tyrosine kinase 3 ligand (Flt3L) dependent and strongly Flt3L responsive, which may relate them to classical DCs. Examination of DC capture of FITC from painted skin, DC isolation from skin explant culture, and from the skin of CCR7 knockout mice which accumulate migDC, demonstrate these cells are cutaneous residents. Langerin-CD11b-Flt3L responsive DC are largely CD24(+) and CX3CR1low and can be depleted from Zbtb46-DTR mice, suggesting classical DC lineage. Langerin-CD11bmigDC present antigen with equal efficiency to other DC subsets ex vivo including classical CD8α cDC and Langerin+CD103+ dermal DC. Finally, transcriptome analysis suggests a close relationship to other skin DC, and a lineage relationship to other classical DC. This work demonstrates that Langerin- CD11b− dermal DC, a previously overlooked cell subset, may be an important player in the cutaneous immune environment

Linking migration and hospital data in England: linkage process and evaluation of bias

Introduction: Difficulties ascertaining migrant status in national data sources such as hospital records have limited large-scale evaluation of migrant healthcare needs in many countries, including England. Linkage of immigration data for migrants and refugees, with National Health Service (NHS) hospital care data enables research into the relationship between migration and health for a large cohort of international migrants. / Objectives: We aimed to describe the linkage process and compare linkage rates between migrant sub-groups to evaluate for potential bias for data on non-EU migrants and resettled refugees linked to Hospital Episode Statistics (HES) in England. / Methods: We used stepwise deterministic linkage to match records from migrants and refugees to a unique healthcare identifier indicating interaction with the NHS (linkage stage 1 to NHS Personal Demographic Services, PDS), and then to hospital records (linkage stage 2 to HES). We calculated linkage rates and compared linked and unlinked migrant characteristics for each linkage stage. / Results: Of the 1,799,307 unique migrant records, 1,134,007 (63%) linked to PDS and 451,689 (25%) linked to at least one hospital record between 01/01/2005 and 23/03/2020. Individuals on work, student, or working holiday visas were less likely to link to a hospital record than those on settlement and dependent visas and refugees. Migrants from the Middle East and North Africa and South Asia were four times more likely to link to at least one hospital record, compared to those from East Asia and the Pacific. Differences in age, sex, visa type, and region of origin between linked and unlinked samples were small to moderate. / Conclusion: This linked dataset represents a unique opportunity to explore healthcare use in migrants. However, lower linkage rates disproportionately affected individuals on shorter-term visas so future studies of these groups may be more biased as a result. Increasing the quality and completeness of identifiers recorded in administrative data could improve data linkage quality