Browsing by Author "Costa, Paulo"
Now showing 1 - 10 of 20
Results Per Page
Sort Options
- Antioxidant and oxidative stress responses in zebrafish brain after exposure to low doses of ionizing radiationPublication . Lemos, Joana; Guimarães, Laura; Vasconcelos, Vítor; Ponte, Fernanda; Costa, Paulo; Metello, Luís F.; Carvalho, António PauloIntroduction: The use of zebrafish – Danio rerio – has grown considerably, demonstrating the increasing interest to use this model in biomedical research. This is essentially due to the level of homology shared with the human genome, complemented by an easy and reasonably affordable practical side. Hence, this work investigated radiobiological effects of exposure to low doses of ionizing radiation in zebrafish.
- Assessing radiobiological effects of diagnostic level doses of ionizing radiation on zebrafish using comet assayPublication . Lemos, Joana; Costa, Pedro; Cunha, Lídia; Carvalho, António Paulo; Neuparth, Teresa; Genésio, Paula; Ponte, Fernanda; Costa, Paulo; Crespo, Paulo; Metello, Luís F.This paper relates with the application of zebrafish – Danio rerio – to the study of radiobiological effects of medical diagnostic level – low doses – of ionizing radiation. In recent years, the use of zebrafish has grown considerably, pointing more and more as a very interesting model in biomedical research, essentially because of the level of homology shared with the human genome, complemented by an easy and reasonably affordable practical side.
- Assessing Radiobiological Effects of Low Doses of Ionizing Radiation on Zebrafish by Bidimensional Gel ElectrophoresisPublication . Lemos, Joana; Costa, Pedro; Cunha, Lídia; Campos, Alexandre; Carvalho, António Paulo; Vasconcelos, Vítor; Genésio, Paula; Ponte, Fernanda; Costa, Paulo; Crespo, Paulo; Metello, Luís F.Aim: This paper relates with a specific task from a larger research project oriented to the development and application of the Zebrafish – Danio rerio – to the study of radiobiological effects of medical diagnostic level – low doses – of ionizing radiation.
- Assessing radiobiological effects of low doses of ionizing radiation on zebrafish muscle by two-dimensional gel electrophoresisPublication . Lemos, Joana; Campos, Alexandre; Carneiro, Mariana; Ribeiro, Tiago; Ponte, Fernanda; Costa, Paulo; Cunha, Lídia; Carvalho, António Paulo; Metello, Luís F.Introduction: This work relates with the application of zebrafish - Danio rerio - to the study of radiobiological effects of low doses of ionizing radiation. In recent years, the use of zebrafish has grown considerably, pointing more and more as a very interesting model in biomedical research, essentially because of the level of homology shared with the human genome, complemented by an easy and reasonably affordable practical side. The two-dimensional gel electrophoresis (2DGE) is a method used for the analysis of complex protein mixtures from biological samples. This method allows the detection of differences in protein expression under different conditions, so allowing creating relations between those differences and the irradiations that were in their basis. The present work aimed at evaluating proteome changes in the zebrafish muscle caused by low doses of X-rays exposure.
- DC motor educational kit: a teaching aid in control theoryPublication . Moreira, António Paulo; Costa, Paulo; Gonçalves, José; Faria, Brígida MónicaThis paper describes a laboratory control theory experiment supported by the use of a DC Motor Educational Kit. The impact, as a teaching aid, of the proposed laboratory control experiment is evaluated, having in mind the student’s feedback. The DC motor that is used in the developed educational Kit is the EMG30, being a low cost 12 V motor equipped with encoders and a 30:1 reduction gearbox. The experiment is based on real hardware and on simulation, using the SimTwo realistic simulation software. In order to implement the realistic simulation the EMG30 model was obtained. Students’ feedback was acquired using a questionnaire and the results confirmed the importance given to these practical experiments.
- Development and Optimization of a Topical Formulation with Castanea sativa Shells Extract Based on the Concept “Quality by Design”Publication . Oliveira, Nágilla; Cádiz-Gurrea, María de La Luz; Silva, Ana Margarida; Macedo, Catarina; Rodrigues, Francisca; Costa, PauloThe proposed study aims to develop and optimize a topical formulation with Castanea sativa shells extract considering the concept of Quality by Design, focusing on a planned development that consider the vulnerabilities of the entire process through risk analysis tools and design of experiments (DoE). A Box–Behnken design with three factors and three levels was used as a statistical tool for the execution of the DoE and the analysis of the response surface methodology responses. The independent variables studied were the quantity of sodium lauryl sulfate (%) (X1), beeswax (%) (X2) and macadamia oil (%) (X3); the dependent variables were pH (Y1), viscosity (Y2) and adhesiveness (Y3). According to the mathematical model, the optimal formulation contains 0.93% of sodium lauryl sulfate, 5.00% of beeswax and 10.00% of macadamia oil. The optimal formulation with the extract was prepared and characterized over the time, regarding organoleptic and technological characteristics, allowing conclusions to be reached regarding its stability. The formulation presented a pleasant odor and was light brown in color, it also demonstrated pseudoplastic-thixotropic behavior and a small reduction in the formulation consistency after 30 days of storage. This study demonstrated the efficiency of the Quality by Design methodology to understand the product variability, supporting that this approach favors a better understanding of the whole process and enables to design a robust development stage, reducing costs and generating high-quality products
- Discovery of a New Xanthone against Glioma: Synthesis and Development of (Pro)liposome FormulationsPublication . Alves, Ana; Correia-da-Silva, Marta; Nunes, Claúdia; Campos, João; Sousa, Emília; Silva, Patrícia; Bousbaa, Hassan; Rodrigues, Francisca; Ferreira, Domingos; Costa, Paulo; Pinto, MadalenaFollowing our previous work on the antitumor activity of acetylated flavonosides, a new acetylated xanthonoside, 3,6-bis(2,3,4,6-tetra-O-acetyl-β-glucopyranosyl)xanthone (2), was synthesized and discovered as a potent inhibitor of tumor cell growth. The synthesis involved the glycosylation of 3,6-di-hydroxyxanthone (1) with acetobromo-α-d-glucose. Glycosylation with silver carbonate decreased the amount of glucose donor needed, comparative to the biphasic glycosylation. Xanthone 2 showed a potent anti-growth activity, with GI50 < 1 μM, in human cell lines of breast, lung, and glioblastoma cancers. Current treatment for invasive brain glioma is still inadequate and new agents against glioblastoma with high brain permeability are urgently needed. To overcome these issues, xanthone 2 was encapsulated in a liposome. To increase the well-known low stability of these drug carriers, a proliposome formulation was developed using the spray drying method. Both formulations were characterized and compared regarding three months stability and in vitro anti-growth activity. While the proliposome formulation showed significantly higher stability, it was at the expense of losing its biocompatibility as a drug carrier in higher concentrations. More importantly, the new xanthone 2 was still able to inhibit the growth of glioblastoma cells after liposome formulation.
- Eco-friendly insights on kiwiberry leaves valorization through in-vitro and in-vivo studiesPublication . Silva, Ana Margarida; Garcia, Juliana; Dall'Acqua, Stefano; Costa, Paulo; Delerue-Matos, Cristina; Rodrigues, FranciscaOn the last decade, the demand for novel active skin ingredients based on sustainable principles arise as a trend. These new concerns transformed the consumer preferences, which are not actually solved by the industry portfolio. Regulatory aspects establish guidelines to assess the safety and efficacy of new cosmetic ingredients, being this step imperative to introduce a new ingredient on the market. Our last studies reported the richness of Actinidia arguta (kiwiberry) leaves in bioactive compounds with potential skin applications, but further studies are necessary to validate this extract. Therefore, the current study aimed to screen the hydroalcoholic extract of A. arguta leaves regarding elastase and hyaluronidase inhibition, achieving excellent results (65.62 ± 2.09% and 54.64 ± 4.17%, respectively). The cell viability was assessed in keratinocytes and fibroblasts (0.1–1000 μg/mL), ensuring the absence of cytotoxic effects. Afterwards, 3D models, namely a skin (EpiSkin™) and an ocular (SkinEthic™ HCE, respectively) model, were used to estimate the irritant potential. The viability achieved in both models after exposure to the extract was, respectively, 55.18 ± 10.60% and 101.15 ± 5.96%. The IL-1α released for the skin and ocular models were, respectively, 0 pg/mL and 35.60 ± 2.61 pg/mL, being the extract classified as non-irritant for both models. Lastly, in-vivo studies performed through a patch test in 10 human volunteers proved the absence of allergic or irritative reactions. Overall, the results attained highlighted that the hydroalcoholic kiwiberry leaves extract is an excellent cosmetic ingredient, being not irritant to skin application
- Estrogen Metabolism-Associated CYP2D6 and IL6-174G/C Polymorphisms in Schistosoma haematobium InfectionPublication . Cardoso, Rita; Lacerda, Pedro; Costa, Paulo; Machado, Ana; Carvalho, André; Bordalo, Adriano; Fernandes, Rúben; Soares, Raquel; Richter, Joachim; Alves, Helena; Botelho, MonicaSchistosoma haematobium is a human blood fluke causing a chronic infection called urogenital schistosomiasis. Squamous cell carcinoma of the urinary bladder (SCC) constitutes chronic sequelae of this infection, and S. haematobium infection is accounted as a risk factor for this type of cancer. This infection is considered a neglected tropical disease and is endemic in numerous countries in Africa and the Middle East. Schistosome eggs produce catechol-estrogens. These estrogenic molecules are metabolized to active quinones that induce modifications in DNA. The cytochrome P450 (CYP) enzymes are a superfamily of mono-oxygenases involved in estrogen biosynthesis and metabolism, the generation of DNA damaging procarcinogens, and the response to anti-estrogen therapies. IL6 Interleukin-6 (IL-6) is a pleiotropic cytokine expressed in various tissues. This cytokine is largely expressed in the female urogenital tract as well as reproductive organs. Very high or very low levels of IL-6 are associated with estrogen metabolism imbalance. In the present study, we investigated the polymorphic variants in the CYP2D6 gene and the C-174G promoter polymorphism of the IL-6 gene on S. haematobium-infected children patients from Guine Bissau. CYP2D6 inactivated alleles (28.5%) and IL6G-174C (13.3%) variants were frequent in S. haematobium-infected patients when compared to previously studied healthy populations (4.5% and 0.05%, respectively). Here we discuss our recent findings on these polymorphisms and whether they can be predictive markers of schistosome infection and/or represent potential biomarkers for urogenital schistosomiasis associated bladder cancer and infertility.
- Evaluation of Radiobiological Effects in Three Distinct Biological ModelsPublication . Lemos, Joana; Costa, Pedro; Cunha, Lídia; Carvalho, António Paulo; Vasconcelos, Vítor; Genésio, Paula; Ponte, Fernanda; Costa, Paulo; Crespo, Paulo; Metello, Luís F.The present work aims to share the process of development of advanced biological models to study radiobiological effects. Recognizing several known limitations and difficulties of the current monolayer cellular models, as well as the increasing difficulties to use advanced biological models, our group has been developing advanced biological alternative models, namely three- dimensional cell cultures and a less explored animal model (the Zebrafish - Danio rerio - which allows the access to inter-generational data, while characterized by a great genetic homology towards the humans). These three models (monolayer cellular model, three-dimensional cell cultures and zebrafish) were externally irradiated with 100mGy, 500mGy or 1Gy. The consequences of that irradiation were studied using cellular and molecular tests.