EM - Artigos Científicos
URI permanente para esta coleção:
Navegar
Entradas recentes
- Super-strong hydrogel composites reinforced with PBO nanofibers for cartilage replacementPublication . Oliveira, Andreia S.; Silva, João C.; Loureiro, Mónica V.; Marques, Ana C.; Kotov, Nicholas A.; Colaço, Rogério; Serro, Ana PaulaCartilage replacement materials exhibiting a set of demanding properties such as high water content, high mechanical stiffness, low friction, and excellent biocompatibility are quite difficult to achieve. Here, poly(p-phenylene-2,6-benzobisoxazole) (PBO) nanofibers are combined with polyvinyl alcohol (PVA) to form a super-strong structure with a performance that surpasses the vast majority of previously existing hydrogels. PVA–PBO composites with water contents in the 59–76% range exhibit tensile and compressive moduli reaching 20.3 and 4.5 MPa, respectively, and a coefficient of friction below 0.08. Further, they are biocompatible and support the viability of chondrocytes for 1 week, with significant improvements in cell adhesion, proliferation, and differentiation compared to PVA. The new composites can be safely sterilized by steam heat or gamma radiation without compromising their integrity and overall performance. In addition, they show potential to be used as local delivery platforms for anti-inflammatory drugs. These attractive features make PVA–PBO composites highly competitive engineered materials with remarkable potential for use in the design of load-bearing tissues. Complementary work has also revealed that these composites will be interesting alternatives in other industrial fields where high thermal and mechanical resistance are essential requirements, or which can take advantage of the pH responsiveness functionality.
- Studying iodine intake of Portuguese children school mealsPublication . Delgado, Inês; Ventura, Marta; Gueifão, Sandra; Assunção, Ricardo; Coelho, Inês; Bento, Alexandra; Silva, José Armando L.; Castanheira, IsabelIodine is an essential trace element, and its nutritional importance is well established. The iodine content of school meals of Portuguese children aged between 6 and 10 years (collected in the metropolitan area of Lisbon) was analyzed by ICP-MS. The samples were cooked with and without iodized salt and additionally some complementary foods were purchased as supplements to the main meals or to the other meal along the day. The results report six meals per day and they suggest that at least one main meals (lunch or dinner) prepared with iodized salt is enough to reach the recommended daily iodine intake (AI), 90 µg/day, not exceeding the tolerable upper intake (UL) level of 300 µg/day. When both main meals are cooked without iodized salt, 11 % of the hypotheses present an iodine content less than 90 µg/day. However, when lunch and dinner are prepared with iodized salt, 1 % exceeds the value of the UL. The food groups with the highest levels of iodine are daily products and fish. These results presuppose a balanced diet without any dietary restrictions. So, for ideological or medical reasons, special attention must be paid to diets with some limitations, such as vegetarian, lactose or high content of proteins free diets.
- Stent for life initiative in Portugal : progress through years and Covid-19 impactPublication . Pereira, Ernesto; Calé, Rita; Pereira, Ângela Maria; Pereira, Hélder; Martins, Luís DiasBackground: During Stent for Life Initiative in Portugal lifetime, positive changes in ST elevation myocardial infarction treatment were observed, by the increase of Primary Angioplasty numbers and improvements in patients’ behaviour towards myocardial infarction, with an increase in those who called 112 and the lower proportion attending non primary percutaneous coronary intervention centres. Despite public awareness campaigns and system educational programmes, patient and system delay did not change significantly over this period. The aim of this study was to address the public awareness campaign effectiveness on peoples’ behaviour facing STEMI, and how Covid-19 has affected STEMI treatment. Methods: Data from 1381 STEMI patients were collected during a one-month period each year, from 2011 to 2016, and during one and a half month, matching first lockdown in Portugal 2020. Four groups were constituted: Group A (2011); Group B (2012&2013); Group C (2015&2016) and group D (2020). Results: The proportion of patients who called 112, increased significantly (35.2% Group A; 38.7% Group B; 44.0% Group C and 49.6% Group D, p = 0.005); significant reduction was observed in the proportion of patients who attended healthcare centres without PPCI (54.5% group A; 47.6% Group B; 43.2% Group C and 40.9% Group D, p = 0.016), but there were no differences on groups comparison. Total ischemic time, measured from symptoms onset to reperfusion increased progressively from group A [250.0 (178.0–430.0)] to D [296.0 (201.0–457.5.8)] p = 0.012, with statistically significant difference between group C and D (p = 0.034). Conclusions: During the term of SFL initiative in Portugal, patients resorted less to primary health centres and called more to 112. These results can be attributed the public awareness campaign. Nevertheless, patient and system delays did not significantly change over this period, mainly in late years of SFL, probably for low efficacy of campaigns and in 2020 due to Covid-19 pandemic.
- Stem cell models of Angelman syndromePublication . Santos, João Camões dos; Appleton, Carolina; Mateus, Francisca Cazaux; Covas, Rita; Bekman, Evguenia Pavlovna; Rocha, Simão Teixeira daAngelman syndrome (AS) is an imprinted neurodevelopmental disorder that lacks a cure, characterized by developmental delay, intellectual impairment, seizures, ataxia, and paroxysmal laughter. The condition arises due to the loss of the maternally inherited copy of the UBE3A gene in neurons. The paternally inherited UBE3A allele is unable to compensate because it is silenced by the expression of an antisense transcript (UBE3A-ATS) on the paternal chromosome. UBE3A, encoding enigmatic E3 ubiquitin ligase variants, regulates target proteins by either modifying their properties/functions or leading them to degradation through the proteasome. Over time, animal models, particularly the Ube3amat−/pat+ Knock-Out (KO) mice, have significantly contributed to our understanding of the molecular mechanisms underlying AS. However, a shift toward human pluripotent stem cell models (PSCs), such as human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), has gained momentum. These stem cell models accurately capture human genetic and cellular characteristics, offering an alternative or a complement to animal experimentation. Human stem cells possess the remarkable ability to recapitulate neurogenesis and generate “brain-in-a-dish” models, making them valuable tools for studying neurodevelopmental disorders like AS. In this review, we provide an overview of the current state-of-the-art human stem cell models of AS and explore their potential to become the preclinical models of choice for drug screening and development, thus propelling AS therapeutic advancements and improving the lives of affected individuals.
- Spectrophotometric analysis of coronal discoloration in vitro induced by bioceramic cementsPublication . Carvalho, Joana A.; Franco, Carlos; Proença, Luís; Neves, João Albernaz; Polido, Mário; Mendes, José João; Azul, Ana ManoThe aim of this study was to evaluate and quantify, in vitro, the extent of coronal discoloration induced by bioceramic materials over time. In total, 44 human monoradicular teeth were divided into four groups (n = 11), according to the applied material: Negative control (NC); White MTA ProRoot® (WMTAP); Biodentine™ (BD); and TotalFill® BC RRM™ Putty (TF). Teeth were immersed in saline solution and incubated at 37 °C; the following periods of time were defined: before incubation: [t0]—without bioceramic material, t1—immediately after the bioceramic material placement; after incubation: t24h—24 h, t7d—7 days, and 30d—30 days. Descriptive and inferential statistical analysis were performed. Cochran’s Q test was used to evaluate coronal discoloration across the different groups, while the Kruskal–Wallis test was employed to determine differences in discoloration among the groups at each time interval. Additionally, the Friedman test was applied to analyze the variations in discoloration within each group over time. A significance level of 5% was set. All experimental groups revealed coronal discoloration over time: NC (p = 0.001), WMTAP (p < 0.001), BD (p = 0.001), and TF (p = 0.006). No significant differences were observed between groups for each time interval (p > 0.05). The WMTAP group varied the most considering the intervals [t0—t1] and [t24h—t7d] (p = 0.037) compared to the remaining experimental groups.
- Self-management ability questionnaire validation in portuguese adults with periodontitisPublication . Gobin, Eloïse; Izidoro, Catarina; Lyra, Patrícia; Morgado, Mariana; Alves, Ricardo Castro; Mendes, José João; Botelho, João; Machado, VanessaObjectives: We aimed to test the psychometric validity of the adapted and translated Self-Management Ability Questionnaire-Short Form (SMAQ-12) to Portuguese. Methods: The translation and adaptation of the SMAQ-12 followed international guidelines. We included 280 participants with chronic periodontitis from the Department of Periodontology of the Egas Moniz Dental Clinic. Participants completed the Portuguese version of the SMAQ-12 (SMAQ-12-PT), a 12-item scale with 3 conceptual domains (Role Management, Medical Management, and Emotional Management). The validity of the content, its construct and internal consistency, as well as test–retest reliability were used to estimate psychometric properties. Results: The SMAQ-12-PT showed an interclass correlation coefficient value of 0.90, with a 95% confidence interval (0.79–0.95; P < .001) and high reliability (Cronbach alpha coefficient ranging between 0.78 and 0.94). Confirmatory factor analysis revealed adequate model fit, with comparative fit index of 0.853, goodness-of-fit of 0.947, and a 0.052 value of root mean squared error of approximation. Conclusions: The SMAQ-12-PT was found to be a valid and reliable instrument in the Portuguese population. Disease management representation for the specialty of periodontology and its impact on periodontal schedules and practices should be evaluated in future studies.
- Rheology of complex topical formulations : an analytical quality by design approach to method optimization and validationPublication . Chiarentin, Lucas; Cardoso, Catarina; Miranda, Margarida; Vitorina, CarlaAnalytical method validation ensures that a method provides trustworthy information about a particular sample when applied in accordance with the predefined protocol. According to regulatory standards, the rheological characteristics of topically applied semisolid formulations are one of the key elements involved in microstructure equivalence documentation. Therefore, for generic drug product manufacturers, it is a dire need to take a step forward in rheology method development and validation procedures. This paper aims to apply Analytical Quality by Design (AQbD) principles towards the development and validation of rheology methods for topical creams, as complex semisolid formulations. Risk assessment was carried out through an Ishikawa diagram and an estimate failure mode, effects, and criticality analysis (FMECA). Sample application, peltier temperature control, and sample rest time were identified as critical method variables (CMVs), and a 23 full factorial design was applied to understand their impact on rotational, creep recovery and, oscillatory measurements. The development of the method was carried out as per the ICH Q8-Q10, and Q14 guidelines and validated according to ICH Q2 (R2) guideline. The method demonstrated adequate precision (RSD < 15%), as well as selectivity. AQbD provided a comprehensive framework for developing a reliable and effective rheology method for this type of formulation.
- Revisiting oral antiseptics, microorganism targets and effectivenessPublication . Garrido, Lisetty; Lyra, Patrícia; Rodrigues, Joana; Viana, João; Mendes, José João; Barroso, HelenaA good oral health status is mostly dependent on good oral hygiene habits, which knowingly impacts systemic health. Although controversial, chemical oral antiseptics can be useful in adjunct use to mechanical dental plaque control techniques in the prevention and management of local and overall health and well-being. This review aims to revisit, gather and update evidence-based clinical indications for the use of the most popular oral antiseptics, considering different types, microorganism targets and effectiveness in order to establish updated clinical recommendations.
- Revisiting alpha-synuclein pathways to inflammationPublication . Lyra, Patrícia; Machado, Vanessa; Rota, Silvia; Chaudhuri, Kallol Ray; Botelho, João; Mendes, José JoãoAlpha-synuclein (α-Syn) is a short presynaptic protein with an active role on synaptic vesicle traffic and the neurotransmitter release and reuptake cycle. The α-Syn pathology intertwines with the formation of Lewy Bodies (multiprotein intraneuronal aggregations), which, combined with inflammatory events, define various α-synucleinopathies, such as Parkinson’s Disease (PD). In this review, we summarize the current knowledge on α-Syn mechanistic pathways to inflammation, as well as the eventual role of microbial dysbiosis on α-Syn. Furthermore, we explore the possible influence of inflammatory mitigation on α-Syn. In conclusion, and given the rising burden of neurodegenerative disorders, it is pressing to clarify the pathophysiological processes underlying α-synucleinopathies, in order to consider the mitigation of existing low-grade chronic inflammatory states as a potential pathway toward the management and prevention of such conditions, with the aim of starting to search for concrete clinical recommendations in this particular population.
- Repeatability of brain activity as measured by a 32-channel EEG system during resistance exercise in healthy young adultsPublication . Domingos, Christophe; Marôco, João Luís; Miranda, Marco; Silva, Carlos; Melo, Xavier; Borrego, CarlaElectroencephalography (EEG) is attracting increasing attention in the sports and exercise fields, as it provides insights into brain behavior during specific tasks. However, it remains unclear if the promising wireless EEG caps provide reliable results despite the artifacts associated with head movement. The present study aims to evaluate the repeatability of brain activity as measured by a wireless 32-channel EEG system (EMOTIV flex cap) during resistance exercises in 18 apparently healthy but physically inactive young adults (10 men and 8 women). Moderate-intensity leg press exercises are performed with two evaluations with 48 h. between. This intensity allows enough time for data analysis while reducing unnecessary but involuntary head movements. Repeated measurements of EEG during the resistance exercise show high repeatability in all frequency bands, with excellent ICCs (>0.90) and bias close to zero, regardless of sex. These results suggest that a 32-channel wireless EEG system can be used to collect data on controlled resistance exercise tasks performed at moderate intensities. Future studies should replicate these results with a bigger sample size and different resistance exercises and intensities.