Percorrer por autor "Pereira, Miguel"
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- Antibiofilm properties of quercus ilex acorn extracts against MRSA and MSSAPublication . Silva, Sara; Costa, Eduardo; Costa, Maria do Rosário; Pereira, Miguel; Coelho, Marta; Pintado, M. E.Biofilms are complex structures that grant microorganisms some survival advantages namely nutrient availability and antimicrobial resistance. As such, the need to find new antimicrobial compounds that are active against these structures is in great demand. Phenolic compounds are described as capable of interfering with the cellular membrane and interact with both intracellular and extracellular proteins, thus they may present an alternative to traditional biofilm control. Acorns have been reported as a rich source of phenolic compounds, particularly tannins, and thus are likely to exhibit some of the properties that are associated with these compounds, namely antimicrobial properties. As such, the present work aimed to assess the antibiofilm properties of hydroethanolic, phenolic rich, acorn extracts against two Staphylococcus aureus strains, one sensitive (MSSA) and one resistant (MRSA) to methicillin. To do so, both microorganisms were exposed to two different sub-MIC concentrations of extracts produced using acorn shells (fresh and roasted) and cotyledons (fresh or roasted). The amount of biofilm produced in the presence of the extracts, after 48 h, was then determined using the microtiter - crystal violet based assay. The results obtained showed that MRSA was the most sensitive strain, with biomass inhibition percentages ranging from 60 to 70%, while for MSSA all inhibition percentages ranged between 29 to 57%. No significant differences between shell and cotyledon were found when considering the results obtained for MRSA. The same was not observed for MSSA where biomass production was significantly higher for roasted cotyledon (2.5 to 20.6%). For this microorganism, it was interesting to note that lower concentrations of the extracts appeared to possess a higher antibiofilm activity (0.7 times more active for fresh or roasted shell extract and 0.6 times more active for fresh cotyledon extracts). Overall, these results indicate that Quercus ilex acorns possess the potential to be an effective means of biofilm control though further studies are still required to fully ascertain their true potential.
- Assessment of prebiotic potential of Akpan-yoghurt-like product and effects on the human intestinal microbiotaPublication . Gullón, Beatriz; Pereira, Miguel; Mestres, Christian; Hounhouigan, Joseph; Pallet, Dominique; Luis Alonso, José; Pintado, ManuelaThe effect of Akpan (yoghurt-like product) consumption on the human intestinal microbiota was examined. The prebiotic potential of Akpan was assessed by in vitro fermentation using, as inocula, individual probiotic strains and faecal samples from three healthy donors. In this latter case, the prebiotic activity was assessed through the quantification of short chain fatty acid (SCFA) production, the evolution of the pH and the evaluation of dynamic bacterial population by fluorescent in situ hybridization (FISH). Results demonstrated that Akpan was metabolized after 44 h of fermentation, exerting a prebiotic effect, similar to that observed for fructooligosaccharides (FOS). All the considered bacterial groups significantly increased after Akpan and FOS fermentation. Under the tested conditions, no significant differences between the SCFA concentration produced by Akpan and FOS after of incubation were detected. Our findings contribute to support the utilization of Akpan as a functional food with potential beneficial effects on gastrointestinal health.
- Bioavailability of phenolic compounds from blueberry leaf infusions (Vaccinium Corymbosum L.) In caco-2 cellsPublication . Silva, Sara; Norberto, Sónia; Costa, Eduardo; Pereira, Miguel; Costa, Maria do Rosário; Coelho, Marta; Faria, Ana; Pintado, M. E.; Calhau, ConceiçãoPhenolic compounds are widespread in plant-derived foodstuffs and therefore abundant in our diet. There are evidences regarding the positive association of their intake with several diseases prevention. Blueberry leaves are of particular interest as they have been described as being rich in phenolic compounds such as chlorogenic acid and quercetin glicosides. Bioavailability is a major issue regarding the biological impact of these compounds in vivo and remains unclear, with few data available on this matter. Studies in CaCo-2 cells (entrocyte cell line) tested the transport of blueberry leaf infusion (optimized to yield the highest amount total phenolics) across this cell line for different incubation times. From the different compounds originally identified only rutin (9%), quercetin-3- glucoside (Q3glu), chlorogenic (7%) and neochlorogenic acids (23%) were transported across the epithelia cells, after 60, 90 and 120 min. From these compounds, neochlorogenic acid and Q3glu exhibit the highest transport rates (23 and 22%, respectively of the original concentration) while for rutin and chlorogenic acid the transport was lower than 10% of the original amount of compound. It was interesting to note that two metabolites, that were not originally present, caffeic and p-coumaric acids were detected after 30 and 60 min, respectively. From this work it was possible to conclude that neocholorogenic acid and Q3glu are more efficiently transported through the CaCo-2 membrane and that this process resulted in the detection of some metabolites that were not originally present.
- Case report of a dilated odontome in the posterior mandiblePublication . Almeida, Bruno; Silva, António; Pereira, Miguel; Silva, Mariana; Nunes, StephanieIntroduction Dens invaginatus (dens in dente) is a developmental malformation resulting from an invagination of enamel organ into the dental papilla, beginning at the crown and sometimes extending into the root before calcification occurs. Dilated odontome is the most extreme form of dens invaginatus and it is extremely rare in the posterior mandible. Presentation of case A 47 years old female patient with occasional episodes of diffuse pain and discomfort in the left posterior mandibular region. The extra-oral examination showed slight facial asymmetry. Panoramic and intra-oral X-rays show an intraosseous circular formation with radiopaque external limits and radiolucent interior. Discussion Computerized tomography scan reveals the bone integrity around the formation, as well as the independence of the neuro-vascular structures of the region. The most likely diagnostic option was dilated odontome. The enucleation procedure was carried out, and the fragments were sent to histopathological examination that revealed a diagnosis consistent with a dilated odontome. Conclusion In this case, the conservative surgical approach after planning was effective and predictable in the treatment of the pathology and patient symptoms without major complications.
- Comparative analysis between synthetic vitamin E and natural antioxidant sources from tomato, carrot and coriander in diets for market-sized dicentrarchus labraxPublication . Pereira, Ricardo; Costa, Mónica; Velasco, Cristina; Cunha, Luís M.; Lima, Rui C.; Baião, Luís F.; Batista, Sónia; Marques, Alexandra; Sá, Tiago; Campos, Débora A.; Pereira, Miguel; Jesus, Diva; Fernández-Boo, Sergio; Costas, Benjamin; Pintado, Manuela; Valente, Luisa M.P.Synthetic vitamin E is commonly used in aquafeeds to prevent oxidative stress in fish and delay feed and flesh oxidation during storage, but consumers’ preferences tend towards natural antioxidant sources. The potential of vegetable antioxidants-rich coproducts, dried tomato (TO), carrot (CA) and coriander (CO) was compared to that of synthetic vitamin E included in diets at either a regular (CTRL; 100 mg kg−1) or reinforced dose (VITE; 500 mg kg−1). Natural antioxidants were added at 2% to the CTRL. Mixes were then extruded and dried, generating five experimental diets that were fed to European sea bass juveniles (114 g) over 12 weeks. Vitamin E and carotenoid content of extruded diets showed signs of degradation. The experimental diets had very limited effects on fish growth or body composition, immunomodulatory response, muscle and liver antioxidant potential, organoleptic properties or consumer acceptance. Altogether, experimental findings suggest that neither a heightened inclusion dose of 500 mg kg−1 of vitamin E, nor a 2% inclusion of natural antioxidants provided additional antioxidant protection, compared to fish fed diets including the regular dose of 100 mg kg−1 of vitamin E.
- Comparative clinical behavior of zirconia versus titanium dental implants: a systematic review and meta-analysis of randomized controlled trialsPublication . Morena, Danilo; Leitão-Almeida, Bruno; Pereira, Miguel; Resende, Rodrigo; Fernandes, Juliana Campos Hasse; Fernandes, Gustavo Vicentis Oliveira; Borges, TiagoObjective: The goal of this systematic review and meta-analysis was to assess whether there were clinically relevant differences in the treatment of edentulous areas comparing zirconia (Zr) and titanium (Ti) dental implants. The null hypothesis is that no differences can be observed in terms of the clinical parameters; the positive hypothesis I is that Zr implants have generally better results compared to Ti implants; and the positive hypothesis II is that Ti implants have a generally superior result than Zr implants. Methods: This review work was registered on the PROSPERO platform, and its development was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. The electronic search process was conducted on three databases (PubMed/Scopus/Web of Science), including randomized controlled trials (RCTs) from the past 10 years (up to April 2024). Identified articles were analyzed and included/excluded based on pre-defined selection and exclusion criteria. The quality assessment and risk of bias were evaluated using a Cochrane risk-of-bias assessment tool specifically designed for randomized trials (RoB2). A meta-analysis was conducted to correlate different treatment options based on the described outcomes; a random-effects model was used in the analysis of the variables. The analysis of heterogeneity was conducted by means of Cochran’s Q-test and Higgins’ I2 statistic. Results: Six RCTs were enrolled; 152 patients (90 males and 62 females) and 448 implants (267 Zr and 181 Ti) were included. Dental implant placement involved both the maxillary and mandibular arches. The implant sites showed heterogeneity in receiving Zr and Ti dental implants; in particular, 22 dental implants were placed in the mid-palatal region and 426 dental implants in the alveolar region (255 were in Zr and 171 in Ti). Regarding the success rate, it was better for Zr but with no statistical difference (p > 0.05); bleeding on probing had slight differences between Ti with 0.34% ± 0.42 and Zr with 0.26% ± 0.36 (p > 0.05); plaque score showed 0.46 ± 0.47 for Ti compared to 0.44 ± 0.49 for Zr (p > 0.05); no statistically significant difference was observed for pink esthetic score (PES). Statistically significant results were found for survival rate, which favored Ti implants (77.6%) compared to Zr (70.3%) (p < 0.05), and for marginal bone loss, which showed less loss in Ti implants (0.18 mm ± 0.47) compared to 0.42 mm ± 0.40 in Zr at 12 months (p < 0.001). Conclusions: The present systematic review and meta-analysis identified the positive hypothesis I and rejected the null and positive hypothesis II; it was possible to conclude that Ti dental implants have a better survival rate and less marginal bone loss than Zr dental implants after 1-year follow-up.
- Dietary inclusion of blood hydrolysates affects muscle growth in European seabass (Dicentrarchus labrax)Publication . Velasco, Cristina; Resende, Daniela; Oliveira, Beatriz; Canada, Paula; Pereira, Miguel; Pereira, Carlos; Pintado, Manuela; Valente, Luisa M. P.Dietary supplementation with hydrolysates has been suggested to influence muscle protein synthesis and fish growth. This study assessed the impact of including 3% swine blood hydrolysates (BH) in a plant-based diet on muscle cellularity and the expression of molecular markers related to muscle fibre proliferation and hypertrophic growth of European seabass. Three BH fractions were obtained by two different processes, autohydrolysis (AH-H) and enzymatic hydrolysis followed by micro- (RMF-H) and nanofiltration (RNF-H). Each BH was added to a commercial-based diet, where 50% of fishmeal was replaced by vegetable proteins (negative control, NC). A fishmeal-based diet was used as positive control, PC. The diets were fed to juveniles (12 g) during 74 days. The RMF group showed down-regulation of myod1 and fgf4, essential to myoblast proliferation and differentiation, and upregulation of mafbx, responsible for protein breakdown, resulting in impairment of muscle hyperplasic growth and the lowest muscle fibres number. However, compensatory growth mechanisms were observed through capn1 downregulation and mymk upregulation, suggesting decreased muscle proteolysis and increased myoblast fusion. Despite this, the compensatory mechanisms were insufficient as RMF group had the worst growth. RNF group had a final weight similar to the NC, but downregulation of fgf4, fgf6 and capn1 may compromise growth potential at long term. The expression of these genes in the AH group was similar to that in the FM-based diet. Despite not having demonstrated growth promotion ability, BH affect muscle growth and cellularity factors, prompting further research on commercial-sized fish to reveal their impact on important commercial traits.
- Effect of the dietary inclusion of blood hydrolysates on European seabass response to stressPublication . Resende, Daniela; Pereira, Ricardo; Velasco, Cristina; Domínguez, David; Pereira, Miguel; Pereira, Carlos; Marques, Bianca; Rocha, Cristina; Pintado, Manuela; Valente, Luísa M. P.
- European seabass response to air exposure: impact of dietary inclusion of bioactive blood hydrolysatesPublication . Resende, Daniela; Pereira, Ricardo; Velasco, Cristina; Domínguez, David; Pereira, Miguel; Pereira, Carlos; Marques, Bianca; Rocha, Cristina; Lima, Rui Costa; Pintado, Manuela; Valente, Luísa M. P.In aquaculture farms, fish are subjected to stress situations, which induce oxidative stress through an imbalance between the generation of reactive oxygen species (ROS) and the scavenging activity of antioxidants. Diet supplementation with functional ingredients to modulate oxidative stress after air exposure was investigated, using bioactive peptides from swine blood hydrolysates (BH), within a circular economy context. Three swine BH were obtained by autohydrolysis (AH) or enzymatically. The enzymatically produced BH were further submitted to a micro- (MF) or nanofiltration (NF). Five isolipidic and isoproteic diets for European seabass were developed: a fishmeal (FM) based diet (positive control, PC), a commercial-based diet where 50% of FM was replaced by vegetable proteins (negative control, NC) and three diets where 3% of each BH was added to the NC. Diets were assigned to triplicate groups of 71 European seabass juveniles (initial weight 12.3 ± 1.4 g), and fed to apparent satiation in a recirculating saltwater system. After 12 weeks, 9 fish per treatment were either immediately sampled or air-exposed for 1 minute and let to recover for 6 hours prior to sampling, in which plasma and liver were collected. Plasmatic cortisol and lactate were elevated for all diets after the air exposure, without differences among diets. Glucose levels were unaffected by diet or stress. Regarding liver oxidative stress markers, lipid peroxidation (LPO) tended to increase after air exposure. Considering the non-stressed fish, MF diet led to the lowest LPO, being significantly lower than the AH, and similar to the remaining diets. Protein oxidation decreased in stressed fish, but did not differ among diets. Liver catalase was significantly lower in NC, NF and AH groups compared to PC and increased after stress. Superoxide dismutase activity was lower for AH and PC diets than for the MF, and it was reduced in stressed fish. The stress response triggered by air exposure involved increased cortisol levels, followed by an increment in plasma lactate. However, none of the BH improved plasma stress response. The stress challenge increased liver LPO through ROS accumulation under oxidative stress. Carbonyls decreased post-stress, likely due to a feedback interaction with the LPO radicals, which reduced protein oxidation. The NF, composed of smaller peptides than the other BH, may modulate European seabass antioxidant defences by lowering catalase levels without increasing LPO, suggesting it could provide exogenous antioxidants to counteract ROS-induced oxidative stress.
- Inclusion of blood hydrolysates in European seabass (D. labrax) diets: impact on nutrient retention and fish resistance to T. maritimum infectionPublication . Resende, Daniela; Costas, Benjamin; Sá, Tiago; Golfetto, Umberto; Machado, Marina; Pereira, Miguel; Pereira, Carlos; Marques, Bianca; Pereira, Ricardo; Pintado, Manuela; Valente, Luisa M. P.Bioactive peptides are small amino acid chains with interesting properties (beyond their nutritional value), including antioxidant, mineral-binding, immunomodulatory or antimicrobial activities [1]. In this study, we hypothesised that including blood hydrolysates (BH) in aquafeeds could promote fish robustness, increase the economic value of animal blood and minimize waste, contributing to a circular economy. Additionally, BH with antimicrobial properties may address the T. maritimum infections that occur in aquaculture farms, with high impact on fish health, well-being and aquaculture production. Three fractions of swine BH obtained by autohydrolysis (AH) or enzymatically were selected. AH was oven dried. The BH obtained enzymatically were further submitted to a micro- (MF) and nanofiltration (NF) and freeze-dried. Dried hydrolysates were then included in five isolipidic and isoproteic diets for European seabass: a fishmeal (FM) based diet (positive control, PC), a commercial-based diet where 50% of FM was replaced by vegetable proteins (negative control, NC) and three diets where 3% of each BH was added to the NC. Diets were assigned to triplicate groups of 71 juveniles (initial weight 12.3±1.4 g), fed three times daily until apparent satiation in a recirculating saltwater system. Growth, nutrient utilisation and whole-body composition were evaluated after 12 weeks. At the end of the trial, ten fish per tank were infected with Tenacibaculum maritimum (3.5×105 cfu/L), in a two-hour water bath, and mortality was assessed for 8 days. Fish fed PC had the highest final weight, followed by NC and NF. The NC had a significantly higher weight than the MF and AH groups. Specific growth rate (SGR) and feed conversion ratio (FCR) of fish fed NF showed no significant differences from those fed PC and NC. Fish fed AH also displayed similar SGR to those fed NF and NC, but differed significantly from the MF. Despite no significant differences among treatments regarding final body composition, lipid and energy retention and gain were lowest in fish fed MF, which also had the lowest condition factor. Protein retention was unaffected by dietary treatments. Regarding the infectious challenge, NF had the lowest mortality rate that differed significantly from the NC and MF groups. Mortality for fish fed AH and PC did not differ from NF. MF showed the highest mortality. Overall, results indicate that dietary supplementation with NF clearly improves the resistance of European seabass to T. maritimum without affecting growth rate and can hence become a valuable ingredient for this species.