Browsing by Author "Fernandes, Rui"
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- Cross-contamination of lettuce with Campylobacter spp. via cooking salt during handling raw poultryPublication . Santos-Ferreira, Nânci; Alves, Ângela; Cardoso, Maria João; Langsrud, Solveig; Malheiro, Ana Rita; Fernandes, Rui; Maia, Rui; Truninger, Mónica; Junqueira, Luís; Nicolau, Anca Ioana; Dumitrascu, Loredana; Skuland, Silje Elisabeth; Kasza, Gyula; Izso, Tekla; Ferreira, Vânia; Teixeira, PaulaCampylobacter spp. are the most common bacterial pathogens associated with human gastroenteritis in industrialized countries. Contaminated chicken is the food vehicle associated with the majority of reported cases of campylobacteriosis, either by the consumption of undercooked meat or via cross- contamination of ready-to-eat (RTE) foods during the handling of contaminated raw chicken parts and carcasses. Our results indicate that cooking salt (used for seasoning) is a potential vehicle for Campylobacter spp. cross-contamination from raw chicken to lettuce, through unwashed hands after handling contaminated chicken. Cross-contamination events were observed even when the chicken skin was contaminated with low levels of Campylobacter spp. (ca. 1.48 Log CFU/g). The pathogen was recovered from seasoned lettuce samples when raw chicken was contaminated with levels ≥ 2.34 Log CFU/g. We also demonstrated that, once introduced into cooking salt, Campylobacter spp. are able to survive in a culturable state up to 4 hours. After six hours, although not detected following an enrichment period in culture medium, intact cells were observed by transmission electron microscopy. These findings reveal a "novel"indirect cross-contamination route of Campylobacter in domestic settings, and a putative contamination source to RTE foods that are seasoned with salt, that might occur if basic food hygiene practices are not adopted by consumers when preparing and cooking poultry dishes.
- Exploring silk Sericin for diabetic wounds: an in situ-forming hydrogel to protect against oxidative stress and improve tissue healing and regenerationPublication . Baptista-Silva, Sara; Bernardes, Beatriz G.; Borges, Sandra; Rodrigues, Ilda; Fernandes, Rui; Gomes-Guerreiro, Susana; Pinto, Marta Teixeira; Pintado, Manuela; Soares, Raquel; Costa, Raquel; Oliveira, Ana LeiteChronic wounds are one of the most frequent complications that are associated with diabetes mellitus. The overproduction of reactive oxygen species (ROS) is a key factor in the delayed healing of a chronic wound. In the present work, we develop a novel in situ-forming silk sericin-based hydrogel (SSH) that is produced by a simple methodology using horseradish peroxidase (HRP) crosslinking as an advanced dressing for wound healing. The antioxidant and angiogenic effects were assessed in vitro and in vivo after in situ application using an excisional wound-healing model in a genetically-induced diabetic db/db mice and though the chick embryo choriollantoic membrane (CAM) assay, respectively. Wounds in diabetic db/db mice that were treated with SSH closed with reduced granulation tissue, decreased wound edge distance, and wound thickness, when compared to Tegaderm, a dressing that is commonly used in the clinic. The hydrogel also promoted a deposition of collagen fibers with smaller diameter which may have had a boost effect in re-epithelialization. SSH treatment slightly induced two important endogenous antioxidant defenses, superoxide dismutase and catalase. A CAM assay made it possible to observe that SSH led to an increase in the number of newly formed vessels without inducing an inflammatory reaction. The present hydrogel may result in a multi-purpose technology with angiogenic, antioxidant, and anti-inflammatory properties, while advancing efficient and organized tissue regeneration.
- Identificação e caracterização de potenciais e-learners: um contributo para a aplicação do e-learning à Educação Médica ContínuaPublication . Fernandes, RuiCom a evolução tecnológica verificada nas últimas décadas, o processo de ensino-aprendizagem tem sofrido alterações no seu padrão, sendo o ensino a distância com apoio das tecnologias de informação e comunicação (TIC), um exemplo. O surgimento de novas formas de ensinar e aprender condiciona o aparecimento, em paralelo, de resistências a essa mudança, o que é inevitável em qualquer modificação metodológica. No ensino centrado no estudante, este tem um papel fulcral nesse processo, pelo que é fundamental conheceras suas características e a opinião sobre os novos para digmas de ensino, o que constitui uma etapa inicial na concepção e distribuição de produtos educativos electrónicos.Com o objectivo de caracterizar uma população médica, de acordo com as suas características demográficas e pessoais, a utilização de ferramentas electrónicas (computador pessoal e Internet) na sua vida pessoal e profissional, e as metodologias utilizadas na educação médica contínua, inquirimos 91 médicos através de inquérito de respostas fechadas administrado à distância (correio tradicional e e-mail). A análise dos resultados evidenciou que a população médica estudada está habituada a utilizar o computador pessoal e a internet para várias actividades do seu quotidiano, incluindo para comunicar nos planos pessoal e profissional, e considera a educação médica contínua importante para o desempenho profissional. Em relação às metodologias de ensino, este estudo demonstrou que os médicos inquiridos, apesar de reconhecerem as TIC como um elemento a ter em conta nas actividades de educação médica, não têm o hábito de utilizar as metodologias de ensino electrónicas, considerando-as menos eficazes para a sua formação, podendo ser complementares às metodologias tradicionais, de tipo presencial.
- Molecular mobility, composition and structure analysis in glycerol plasticised chitosan filmsPublication . Fundo, Joana; Fernandes, Rui; Almeida, Pedro M.; Carvalho, Alexandra; Feio, Gabriel; Silva, Cristina L. M.; Quintas, MafaldaThis study was developed with the purpose to investigate the effect of polysaccharide/plasticiser concentration on the microstructure and molecular dynamics of polymeric film systems, using transmission electron microscope imaging (TEM) and nuclear magnetic resonance (NMR) techniques. Experiments were carried out in chitosan/glycerol films prepared with solutions of different composition. The films obtained after drying and equilibration were characterised in terms of composition, thickness and water activity. Results show that glycerol quantities used in film forming solutions were responsible for films composition; while polymer/total plasticiser ratio in the solution determined the thickness (and thus structure) of the films. These results were confirmed by TEM. NMR allowed understanding the films molecular rearrangement. Two different behaviours for the two components analysed, water and glycerol were observed: the first is predominantly moving free in the matrix, while glycerol is mainly bounded to the chitosan chain.
- Para uma educação inclusiva: Manual de apoio à práticaPublication . Pereira, Filomena; Crespo, Alexandra; Trindade, Ana Rosa; Cosme, Ariana; Croca, Fernanda; Breia, Graça; Fernandes, Rui; Carvalho, Marisa
- Potential biological properties of lycopene in a self-emulsifying drug delivery systemPublication . Báo, Sônia Nair; Machado, Manuela; Silva, Ana Luisa da; Melo, Adma; Cunha, Sara; Sousa, Sérgio S.; Malheiro, Ana Rita; Fernandes, Rui; Leite, José Roberto S. A.; Vasconcelos, Andreanne G.; Relvas, João; Pintado, ManuelaIn recent years, lycopene has been highlighted due to its antioxidant and anti-inflammatory properties, associated with a beneficial effect on human health. The aim of this study was to advance the studies of antioxidant and anti-inflammatory mechanisms on human keratinocytes cells (HaCaT) of a self-emulsifying drug delivery system (SEDDS) loaded with lycopene purified from red guava (nanoLPG). The characteristics of nanoLPG were a hydrodynamic diameter of 205 nm, a polydispersity index of 0.21 and a zeta potential of −20.57, providing physical stability for the nanosystem. NanoLPG demonstrated antioxidant capacity, as shown using the ORAC methodology, and prevented DNA degradation (DNA agarose). Proinflammatory activity was evaluated by quantifying the cytokines TNF-α, IL-6 and IL-8, with only IL-8 showing a significant increase (p < 0.0001). NanoLPG showed greater inhibition of the tyrosinase and elastase enzymes, involved in the skin aging process, compared to purified lycopene (LPG). In vitro treatment for 24 h with 5.0 µg/mL of nanoLPG did not affect the viability of HaCaT cells. The ultrastructure of HaCaT cells demonstrated the maintenance of morphology. This contrasts with endoplasmic reticulum stresses and autophagic vacuoles when treated with LPG after stimulation or not with LPS. Therefore, the use of lycopene in a nanoemulsion may be beneficial in strategies and products associated with skin health.
- Religião e cultura popPublication . Tuna, Cátia; Fernandes, Rui
- The protective effect of food matrices on Listeria lytic bacteriophage P100 application towards high pressure processingPublication . Komora, Norton; Bruschi, Carolina; Ferreira, Vânia; Maciel, Cláudia; Brandão, Teresa R. S.; Fernandes, Rui; Saraiva, Jorge A.; Castro, Sónia Marília; Teixeira, PaulaThe application of lytic phages as biocontrol agents is emerging as a promising strategy towards elimination or reduction of foodborne pathogens in a variety of food products. This technology is particularly advantageous for minimally processed and ready-to-eat (RTE) foods. In this study, the potential use of Listex™ P100 combined with high hydrostatic pressure (HPP), to enhance the control of Listeria monocytogenes in food was evaluated. For that, the effect of three pressures (200, 300 or 400 MPa; 5 min, 10 °C) on phage P100 stability was tested when inoculated in six different matrices: phosphate buffered saline (PBS, pH 7.4); apple juice (pH 3.41); orange/carrot nectar (pH 3.54); UHT whole milk (pH 6.73); and, two traditional Portuguese fermented products, “Serra da Estrela” cheese (pH 5.66) and “Alheira”, a meat sausage (pH 6.07). The results showed that treatment at 400 MPa reduced phage titres to below the detection level in all matrices, whereas at milder pressures the survival of the phage was matrix dependent. “Alheira”, “Serra da Estrela” cheese and UHT whole milk were shown to be baroprotective matrices that support phage P100 application in HHP up to 300 MPa; however, an accentuated phage inactivation was observed in apple and orange/carrot nectar, which may be related to the acidic pH values of these matrices. The initial phage load did not affect the inactivation rate during HHP processing (300 MPa, 5 min, 10 °C) in PBS, cheese, sausage or milk matrices, and the phage titres were stable in these matrices during storage at 4 °C for 28 days for milk and 60 days for “Alheira” and “Serra da Estrela” cheese. In addition, a baroprotective effect on phage stability was observed when PBS was supplemented with reducing sugars, dextrin, casein, and tween 80. In conclusion, at mild HHP treatment, phage P100 remained active in specific matrices and seems to present potential to be added in non-thermal inactivation of L. monocytogenes.