RCAAP Repository

A traqueostomia consiste numa técnica cirúrgica onde é realizada a abertura da traqueia para o exterior. Pode ser permanente ou temporária, dependendo das características e comorbilidades do doente. Este procedimento, tem sido um fator fundamental para a sobrevivência na população pediátrica nos últimos tempos. As principais indicações para a sua realização são a entubação oro-traqueal prolongada e obstrução da via aérea superior (anatómica ou infeciosa). Devido à melhoria dos cuidados médicos, a necessidade de realização deste procedimento tem vindo a diminuir e as suas indicações têm-se alterado, com as causas neurológicas e cardiopulmonares a ganharem maior relevância. Este procedimento está associado a maior taxa de morbilidade e mortalidade comparativamente com o adulto, relacionado com a anestesia, o procedimento em si e com outros cuidados pós-operatórios. Contudo, o que tem sido constatado é uma melhoria dos cuidados médicos com diminuição da realização de traqueostomias. Parte deve-se a toda a evolução de conhecimentos médicos, vacinação, com consequente diminuição das traqueostomias realizadas por razões de infeção aguda, à implementação de protocolos hospitalares e educação das famílias, tornando assim possível uma extubação mais rápida, segura e com maior redução de complicações e mortalidade.

A discussão como método de ensino-aprendizagem.

The influenza virus fusion process, whereby the virus fuses its envelope with the host endosome membrane to release the genetic material, takes place in the acidic late endosome environment. Acidification triggers a large conformational change in the fusion protein, hemagglutinin (HA), which enables the insertion of the N-terminal region of the HA2 subunit, known as the fusion peptide, into the membrane of the host endosome. However, the mechanism by which pH modulates the molecular properties of the fusion peptide remains unclear. To answer this question, we performed the first constant-pH molecular dynamics simulations of the influenza fusion peptide in a membrane, extending for 40 µs of aggregated time. The simulations were combined with spectroscopic data, which showed that the peptide is twofold more active in promoting lipid mixing of model membranes at pH 5 than at pH 7.4. The realistic treatment of protonation introduced by the constant-pH molecular dynamics simulations revealed that low pH stabilizes a vertical membrane-spanning conformation and leads to more frequent contacts between the fusion peptide and the lipid headgroups, which may explain the increase in activity. The study also revealed that the N-terminal region is determinant for the peptide's effect on the membrane.

Alzheimer's disease (AD) is a neurodegenerative disease characterized by aberrant amyloid-β (Aβ) and hyperphosphorylated tau aggregation. We have previously investigated the involvement of SEPTIN family members in AD-related cellular processes and discovered a role for SEPTIN8 in the sorting and accumulation of β-secretase. Here, we elucidated the potential role of SEPTIN5, an interaction partner of SEPTIN8, in the cellular processes relevant for AD, including amyloid precursor protein (APP) processing and the generation of Aβ. The in vitro and in vivo studies both revealed that the downregulation of SEPTIN5 reduced the levels of APP C-terminal fragments (APP CTFs) and Aβ in neuronal cells and in the cortex of Septin5 knockout mice. Mechanistic elucidation revealed that the downregulation of SEPTIN5 increased the degradation of APP CTFs, without affecting the secretory pathway-related trafficking or the endocytosis of APP. Furthermore, we found that the APP CTFs were degraded, to a large extent, via the autophagosomal pathway and that the downregulation of SEPTIN5 enhanced autophagosomal activity in neuronal cells as indicated by altered levels of key autophagosomal markers. Collectively, our data suggest that the downregulation of SEPTIN5 increases the autophagy-mediated degradation of APP CTFs, leading to reduced levels of Aβ in neuronal cells.

Colorectal cancer (CRC) is one of the leading causes of mortality and morbidity in the world. Being a heterogeneous disease, cancer therapy and prognosis represent a significant challenge to medical care. The molecular information improves the accuracy with which patients are classified and treated since similar pathologies may show different clinical outcomes and other responses to treatment. However, the high dimensionality of gene expression data makes the selection of novel genes a problematic task. We propose TCox, a novel penalization function for Cox models, which promotes the selection of genes that have distinct correlation patterns in normal vs. tumor tissues. We compare TCox to other regularized survival models, Elastic Net, HubCox, and OrphanCox. Gene expression and clinical data of CRC and normal (TCGA) patients are used for model evaluation. Each model is tested 100 times. Within a specific run, eighteen of the features selected by TCox are also selected by the other survival regression models tested, therefore undoubtedly being crucial players in the survival of colorectal cancer patients. Moreover, the TCox model exclusively selects genes able to categorize patients into significant risk groups. Our work demonstrates the ability of the proposed weighted regularizer TCox to disclose novel molecular drivers in CRC survival by accounting for correlation-based network information from both tumor and normal tissue. The results presented support the relevance of network information for biomarker identification in high-dimensional gene expression data and foster new directions for the development of network-based feature selection methods in precision oncology.

SARS-CoV-2 has emerged as a human pathogen, causing clinical signs, from fever to pneumonia-COVID-19-but may remain mild or asymptomatic. To understand the continuing spread of the virus, to detect those who are and were infected, and to follow the immune response longitudinally, reliable and robust assays for SARS-CoV-2 detection and immunological monitoring are needed. We quantified IgM, IgG, and IgA antibodies recognizing the SARS-CoV-2 receptor-binding domain (RBD) or the Spike (S) protein over a period of 6 months following COVID-19 onset. We report the detailed setup to monitor the humoral immune response from over 300 COVID-19 hospital patients and healthcare workers, 2500 University staff, and 198 post-COVID-19 volunteers. Anti-SARS-CoV-2 antibody responses follow a classic pattern with a rapid increase within the first three weeks after symptoms. Although titres reduce subsequently, the ability to detect anti-SARS-CoV-2 IgG antibodies remained robust with confirmed neutralization activity for up to 6 months in a large proportion of previously virus-positive screened subjects. Our work provides detailed information for the assays used, facilitating further and longitudinal analysis of protective immunity to SARS-CoV-2. Importantly, it highlights a continued level of circulating neutralising antibodies in most people with confirmed SARS-CoV-2.

Plasmodium parasites, causative agents of malaria, scavenge host nutrients to sustain their intracellular replication. Modulation of the host's nutritional status can potentially help control infection by limiting the parasite's access to nutrients, or by boosting the immune system. Here, we show that dietary supplementation of mice employing a combination of arginine (R) with two additional amino acids, lysine (K) and valine (V), termed RKV, significantly decreases Plasmodium liver infection. RKV supplementation results in the elimination of parasites at a late stage of their development in the liver. Our data employing genetic knockout mouse models and in vivo depletion of specific cell populations suggest that RKV supplementation boosts the host's overall innate immune response, and that parasite elimination is dependent on MyD88 signaling in immune cells. The immunostimulatory effect of RKV supplementation opens a potential role for dietary supplementation as an adjuvant for prophylaxis or immunization strategies against Plasmodium infection.

Introdução: Com o aumento das necessidades de cuidados paliativos (CP), numa população cada vez mais idosa e com doenças crónicas, torna-se essencial formar os futuros médicos nesta área. Existe informação escassa acerca das perspetivas dos estudantes de Medicina (EM) relativamente à morte e ao processo de morrer em Portugal. O principal objetivo deste estudo é analisar as opiniões dos EM sobre o que constitui uma “boa morte”. Métodos: Estudo qualitativo, com um questionário online, anónimo, respondido pelos EM. Estes tinham de classificar a sua concordância com algumas afirmações sobre as preferências dos doentes em fim-de-vida. As respostas foram analisadas descritiva e correlativamente. Resultados: Foram incluídos 775 EM, do primeiro ao sexto ano, das 8 escolas médicas portuguesas. Mais de 95% dos EM concordou que os doentes em fim-de-vida querem: ter os seus sintomas aliviados; ser respeitados e ver honradas as suas necessidades espirituais; estar rodeados de entes queridos; ser envolvidos nas decisões acerca dos seus tratamentos; completar assuntos pendentes; não ser um fardo físico e psicológico para as famílias e ser preparados para morrer e despedir-se dos seus familiares e amigos. Os EM concordaram menos com: os doentes querem que as suas famílias saibam toda a verdade acerca da sua doença; não desejam receber tratamentos para prolongar as suas vidas quando as hipóteses de sobrevivência são baixas. Cerca de 37% dos EM consideram ter conhecimentos “muito insuficientes/insuficientes” sobre CP e cuidados em fim-de-vida; menos de 7% opinou que os seus conhecimentos são “muito bons/excelentes”. Este nível de conhecimento acontece em 23% dos EM do 6º ano. Conclusão: Este estudo contribui para a melhoria da educação médica especialmente na área dos CP, tendo implicações práticas no desenvolvimento futuro dos currículos de CP existentes nas escolas médicas de Portugal.

Ctn[15-34], the C-terminal fragment of crotalicidin, an antimicrobial peptide from the South American rattlesnake Crotalus durissus terrificus venom, displays remarkable anti-infective and anti-proliferative activities. Herein, its activity on Candida albicans biofilms and its interaction with the cytoplasmic membrane of the fungal cell and with a biomembrane model in vitro was investigated. A standard C. albicans strain and a fluconazole-resistant clinical isolate were exposed to the peptide at its minimum inhibitory concentration (MIC) (10 µM) and up to 100 × MIC to inhibit biofilm formation and its eradication. A viability test using XTT and fluorescent dyes, confocal laser scanning microscopy, and atomic force microscopy (AFM) were used to observe the antibiofilm effect. To evaluate the importance of membrane composition on Ctn[15-34] activity, C. albicans protoplasts were also tested. Fluorescence assays using di-8-ANEPPS, dynamic light scattering, and zeta potential measurements using liposomes, protoplasts, and C. albicans cells indicated a direct mechanism of action that was dependent on membrane interaction and disruption. Overall, Ctn[15-34] showed to be an effective antifungal peptide, displaying antibiofilm activity and, importantly, interacting with and disrupting fungal plasma membrane.

Key-concepts as gentrification and touristification – and many other correlated to them – have recently moved from the academic lexicon to the political and public one. At the same time, they “travelled” from places in which they have been coined – British and North American cities – to be used all around the world. This article discusses some issues about the application of those concepts in the European South; it then proposes a new usage, based on the concept of articulation, analytically more accurate and politically more vivid.

Plasmodium parasites possess a translocon that exports parasite proteins into the infected erythrocyte. Although the translocon components are also expressed during the mosquito and liver stage of infection, their function remains unexplored. Here, using a combination of genetic and chemical assays, we show that the translocon component Exported Protein 2 (EXP2) is critical for invasion of hepatocytes. EXP2 is a pore-forming protein that is secreted from the sporozoite upon contact with the host cell milieu. EXP2-deficient sporozoites are impaired in invasion, which can be rescued by the exogenous administration of recombinant EXP2 and alpha-hemolysin (an S. aureus pore-forming protein), as well as by acid sphingomyelinase. The latter, together with the negative impact of chemical and genetic inhibition of acid sphingomyelinase on invasion, reveals that EXP2 pore-forming activity induces hepatocyte membrane repair, which plays a key role in parasite invasion. Overall, our findings establish a novel and critical function for EXP2 that leads to an active participation of the host cell in Plasmodium sporozoite invasion, challenging the current view of the establishment of liver stage infection.

Meningococcal meningitis remains a substantial cause of mortality and morbidity worldwide. Until recently, countries in the African meningitis belt were susceptible to devastating outbreaks, largely attributed to serogroup A Neisseria meningitidis (MenA). Vaccination with glycoconjugates of MenA capsular polysaccharide led to an almost complete elimination of MenA clinical cases. To understand the molecular basis of vaccine-induced protection, we generated a panel of oligosaccharide fragments of different lengths and tested them with polyclonal and monoclonal antibodies by inhibition enzyme-linked immunosorbent assay, surface plasmon resonance, and competitive human serum bactericidal assay, which is a surrogate for protection. The epitope was shown to optimize between three and six repeating units and to be O-acetylated. The molecular interactions between a protective monoclonal antibody and a MenA capsular polysaccharide fragment were further elucidated at the atomic level by saturation transfer difference NMR spectroscopy and X-ray crystallography. The epitope consists of a trisaccharide anchored to the antibody via the O- and N-acetyl moieties through either H-bonding or CH–π interactions. In silico docking showed that 3-O-acetylation of the upstream residue is essential for antibody binding, while O-acetate could be equally accommodated at three and four positions of the other two residues. These results shed light on the mechanism of action of current MenA vaccines and provide a foundation for the rational design of improved therapies.

Vários educadores em ciência defendem a inclusão da discussão de questões sociocientíficas controversas nos currículos de ciências em resultado das suas potencialidades tanto na aprendizagem dos conteúdos, dos processos e da natureza da ciência e da tecnologia, como no desenvolvimento cognitivo, social, político, moral e ético dos alunos (Levinson, 2006; Millar, 1997; Nelkin, 1992; Reis, 1997; Sadler, 2004; Zeidler e Lewis, 2003). Contudo, apesar de todas as evidências empíricas relativamente ao seu potencial educacional, as actividades de discussão de questões sociocientíficas controversas não são realizadas em muitas aulas de ciências, mesmo quando integram as orientações curriculares e os professores consideram importante a sua realização. Esta investigação de índole qualitativa, baseada em estudos de caso, pretendeu estudar os factores que influenciam a realização de actividades de discussão de questões sociocientíficas controversas. Através da análise de dados provenientes de entrevistas e da observação de sequências de aulas procurou-se compreender os factores que motivam os professores a realizarem este tipo de actividade nas suas aulas. Os dois estudos de caso revelam que as controvérsias actuais nas áreas da biotecnologia, da genética molecular e das ciências médicas parecem ter tido impacto nas concepções das professoras reforçando, nomeadamente, a concepção de ciência como empreendimento dinâmico, em constante evolução e controverso, com interacções múltiplas com a tecnologia e a sociedade. Contudo, verifica-se que as ideias destas professoras acerca do empreendimento científico e da educação científica nem sempre se reflectem na sua prática de sala de aula. Diversos factores inerentes aos professores, aos alunos e ao sistema educativo parecem afectar a coerência entre as concepções e as práticas. Assim, a realização de actividades de discussão de questões sociocientíficas controversas depende, decisivamente, das convicções das professoras acerca da relevância educacional destas actividades e dos conhecimentos necessários à sua implementação em sala de aula.

Nanoparticles (NPs), as drug delivery systems, appear to be a promising tool for prolonged therapeutic strategies as they allow a controlled drug release over time. However, most of the studies found in the literature simply contemplate the use of a single or low number of dosages with low NPs concentrations. In the context of chronic diseases, like Alzheimer's disease, cancer or human immunodeficiency virus (HIV), where the therapeutic scheme is also chronic, studies with numerous repeated dosages are often neglected.

A Síndrome de Munchausen por Procuração é uma forma rara de abuso devido a falsificação de doença. É atribuído ao perpetrador o diagnóstico de Perturbação Factícia Imposta em Outra Pessoa. As vítimas são frequentemente crianças. Os perpetradores são frequentemente mulheres num papel materno, e poderão ter associados conflitos familiares, perturbações da personalidade, ou outras perturbações psiquiátricas. Este estudo pretende rever os casos clínicos publicados na literatura nos últimos 15 anos. Extraímos dados relevantes de 108 artigos, incluindo 54 artigos com 81 casos clínicos. A distribuição de sexo entre vítimas foi equitativa (51% masculino, 43% feminino, 6% não reportado), consistindo na maioria em crianças com média de idades de 5 anos. Os perpetradores foram quase sempre do sexo feminino (91% feminino, 1% feminino e masculino, 8% não reportado). Vinte e três casos (28%) tinham um perpetrador com diagnóstico psiquiátrico conhecido: Perturbação Factícia Imposta no Próprio (10%), Depressão (9%), e Perturbações da Personalidade (7%). Mais de um terço (36%) referiu conflito familiar/marital ou abuso. Catorze casos (17%) tinham perpetradores que trabalhavam na área da saúde. A forma mais comum de falsificação foi Indução (74%), contudo 15% dos casos apresentava mais do que um tipo de falsificação. Na evolução encontrámos: separação do perpetrador e vítima (37%); sem acompanhamento reportado (22%); prisão do perpetrador (14%); morte da vítima (12%); tratamento psicológico ou psiquiátrico (10%); reunificação de perpetrador com vítima (4%); suicídio do perpetrador (1%). Mais de três quartos dos casos revelaram-se recorrentes. Os resultados reiteram que o reconhecimento das formas mais comuns da Síndrome de Munchausen por Procuração permitem aos médicos identificá-las em contexto clínico.

Neurotrophins are a well-known family of neurotrophic factors that play an important role both in the central and peripheral nervous systems, where they modulate neuronal survival, development, function and plasticity. Brain-derived neurotrophic factor (BDNF) possesses diverse biological functions which are mediated by the activation of two main classes of receptors, the tropomyosin-related kinase (Trk) B and the p75 neurotrophin receptor (p75NTR). The therapeutic potential of BDNF has drawn attention since dysregulation of its signalling cascades has been suggested to underlie the pathogenesis of both common and rare diseases. Multiple strategies targeting this neurotrophin have been tested; most have found obstacles that ultimately hampered their effectiveness. This review focuses on the involvement of BDNF and its receptors in the pathophysiology of Alzheimer's disease (AD), Amyotrophic Lateral Sclerosis (ALS) and Rett Syndrome (RTT). We describe the known mechanisms leading to the impairment of BDNF/TrkB signalling in these disorders. Such mechanistic insight highlights how BDNF signalling compromise can take various shapes, nearly disease-specific. Therefore, BDNF-based therapeutic strategies must be specifically tailored and are more likely to succeed if a combination of resources is employed.

No summary/description provided

Mesenchymal stromal cells (MSC) hold great promise for tissue engineering and cell-based therapies due to their multilineage differentiation potential and intrinsic immunomodulatory and trophic activities. Over the past years, increasing evidence has proposed extracellular vesicles (EVs) as mediators of many of the MSC-associated therapeutic features. EVs have emerged as mediators of intercellular communication, being associated with multiple physiological processes, but also in the pathogenesis of several diseases. EVs are derived from cell membranes, allowing high biocompatibility to target cells, while their small size makes them ideal candidates to cross biological barriers. Despite the promising potential of EVs for therapeutic applications, robust manufacturing processes that would increase the consistency and scalability of EV production are still lacking. In this work, EVs were produced by MSC isolated from different human tissue sources [bone marrow (BM), adipose tissue (AT), and umbilical cord matrix (UCM)]. A serum-/xeno-free microcarrier-based culture system was implemented in a Vertical-WheelTM bioreactor (VWBR), employing a human platelet lysate culture supplement (UltraGROTM-PURE), toward the scalable production of MSC-derived EVs (MSC-EVs). The morphology and structure of the manufactured EVs were assessed by atomic force microscopy, while EV protein markers were successfully identified in EVs by Western blot, and EV surface charge was maintained relatively constant (between −15.5 ± 1.6 mV and −19.4 ± 1.4 mV), as determined by zeta potential measurements. When compared to traditional culture systems under static conditions (T-flasks), the VWBR system allowed the production of EVs at higher concentration (i.e., EV concentration in the conditioned medium) (5.7-fold increase overall) and productivity (i.e., amount of EVs generated per cell) (3-fold increase overall). BM, AT and UCM MSC cultured in the VWBR system yielded an average of 2.8 ± 0.1 × 1011, 3.1 ± 1.3 × 1011, and 4.1 ± 1.7 × 1011 EV particles (n = 3), respectively, in a 60 mL final volume. This bioreactor system also allowed to obtain a more robust MSC-EV production, regarding their purity, compared to static culture. Overall, we demonstrate that this scalable culture system can robustly manufacture EVs from MSC derived from different tissue sources, toward the development of novel therapeutic products.

No summary/description provided

A Obstrução Laríngea Induzida pelo Exercício (OLIE) designa uma entidade clínica na qual ocorre um encerramento inapropriado da laringe durante o exercício. No passado, a falta de consenso na literatura quanto à sua nomenclatura dificultou o progresso da investigação sobre este tópico. Este trabalho tem como objectivo rever a literatura sobre o tema para compreender qual o panorama do conhecimento sobre a sua epidemiologia, fisiopatologia, meios complementares de diagnóstico e recomendações terapêuticas mais actuais. O diagnóstico da OLIE baseia-se em conjunto na apresentação clínica - sintomas respiratórios (estridor, dispneia) no pico do exercício físico – e na visualização de obstrução através de um Teste de Laringoscopia Contínua durante o Exercício (teste LCE) - meio complementar de diagnóstico gold standard para OLIE. A terapêutica médica tem por base terapia comportamental e treino de respiração (técnicas de controlo laríngeo), enquanto a terapêutica cirúrgica (supraglotoplastia) se reserva para OLIE do tipo supra-glótica. Apesar de se estimar uma elevada prevalência - sobretudo na população mais jovem e do sexo feminino -, e desta apresentar um impacto bastante significativo na vida dos doentes, muitos aspectos ainda não estão completamente compreendidos, pese embora nos últimos anos terem sido feitos alguns avanços. Assim, são necessários estudos mais robustos que permitam um diagnóstico preciso e esclarecimento de estratégias terapêuticas eficazes para esta patologia que se apresenta como um importante diagnóstico diferencial de asma.