Browsing by Author "Machado, A."
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- Active polylactic acid film incorporated with green tea extract: Development, characterization and effectivenessPublication . Martins, Carla; Vilarinho, Fernanda; Sanches-Silva, A.; Andrade, Mariana; Machado, A.; Vaz, M.F.; Ramos, F.A new antioxidant active packaging film has been developed based on polylactic acid (PLA) in which green tea extract (GTE) has been immobilized by extrusion. Two GTE concentrations were tested, 1% (w/w) and 2% (w/ w). Four GT samples were compared regarding their antioxidant capacity (by DPPH radical scavenging method and β-carotene bleaching method), total phenolics content (TPC) and total flavonoids content (TFC). The commercial GTE presented with highest antioxidant capacity by the DPPH radical assay (EC50=0.12 ± 0.00 mg/mL) and the highest TPC (416 ± 9.95 mg gallic acid equivalents (GAE)/g extract) and it was selected to be incorporated in the active film. Films were evaluated regarding their mechanical properties (e.g. tensile strength decreased 12% with the incorporation of GTE in the PLA matrix and strain at break increased 9.6 and 36% with the addition of 1 and 2% of GTE) and water vapour transmission rates (watervapour barrier properties improved with the addition of higher amounts of GTE). The study of the effectiveness of PLA/GTE films against lipid oxidation was performed by the following methods: peroxide value, p-anisidine value, thiobarbituric acid reactive substances (TBARS) assay and hexanal monitoring, after packaging smoked salmon slices during different storage times (0, 7, 15, 30, 45 and 60 days). The results showed that the incorporation of GTE in the PLA films protects the smoked salmon from lipid oxidation in the different storage times tested. However, additional studies should be performed to better understand the GTE mechanism of action as the results suggest a pro-oxidant effect of PLA/GTE 2% after 60 days of storage and to evaluate the potential antimicrobial activity of active films.
- Estrogen Metabolism-Associated CYP2D6 and IL6-174G/C Polymorphisms in Schistosoma haematobium InfectionPublication . Cardoso, R.; Lacerda, P.C.; Costa, P.P.; Machado, A.; Carvalho, A.; Bordalo, A.; Fernandes, R.; Soares, R.; Richter, J.; Alves, H.; Botelho, M.C.Schistosoma 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.
- Filme ativo com extrato de chá verde: eficácia contra a oxidação lipídicaPublication . Martins, Cristiana; Vilarinho, Fernanda; Andrade, M.; Sanches Silva, A.; Machado, A.; Ramos, F.; Castilho, M.C.As embalagens ativas têm como objetivo proteger e prolongar a vida útil dos alimentos, aumentando a sua qualidade, segurança e integridade. Na industria alimentar, este conceito de embalagem ativa foi aplicado como forma de controlar o fenomeno da oxidacao lipidica em alimentos com alto teor de gordura, sendo que esta e uma das principais causas de perda de qualidade destes alimentos. A composição química do chá verde tem revelado um grande interesse no que diz respeito a prevenção da oxidação lipídica. Na sua constituição, as folhas de chá verde possuem um teor elevado de compostos fenólicos, que tem sido associados a sua atividade antioxidante. Devido às suas propriedades, o chá verde e considerado um ótimo agente antioxidante natural. O poli (acido láctico) ou ácido poliláctico (PLA) e um polímero alifático cujo monómero e derivado de recursos renováveis, como amido de milho, raízes de tapioca e cana de açúcar. O polímero e formado através da fermentação de amido e condensação de ácido láctico. No presente estudo, fatias de salmão fumado foram embaladas com um filme de PLA, com extrato de chá verde incorporado em diferentes concentrações, 1% e 2%, e, posteriormente, armazenadas durante 7, 15, 30, 45 e 60 dias, em refrigeração. Um filme de PLA sem o extrato de chá verde foi usado como controlo. Para avaliar a eficácia do filme ativo contra a oxidação lipídica, utilizou-se o teste de Substancias Reativas ao Ácido Tiobarbiturico (TBARS). Este ensaio mede o conteudo de malonaldeido (MDA) que e formado durante a oxidação lipídica pela decomposição dos ácidos gordos polinsaturados em hidroperoxidos. Os resultados foram expressos em mg de MDA por kg de salmão fumado. Os resultados mostraram que as fatias de salmão fumado embaladas com o filme de PLA/chá verde apresentaram menor teor de MDA do que aquelas embaladas com o filme controlo. As fatias de salmão fumado embaladas com o PLA/chá verde2% apresentaram menor quantidade de MDA em todos os momentos de contacto, exceto apos 15 dias, onde se verificou menor teor de MDA nas fatias de salmão embaladas com o filme ativo com 1% de extrato de chá verde. Estes resultados mostraram que a incorporação do extrato de chá verde no PLA protege o salmão fumado da oxidação lipídica. Contudo, devem ser realizados estudos adicionais para confirmar a inibição da oxidação lipídica, como o índice de peróxido, o valor de p-anisidina e a determinação do hexanal.
- Schistosoma haematobium in Guinea-Bissau: unacknowledged morbidity due to a particularly neglected parasite in a particularly neglected countryPublication . Botelho, M.C.; Machado, A.; Carvalho, A.; Vilaça, M.; Conceição, O.; Rosa, F.; Alves, H.; Richter, J.; Bordalo, A.A.Schistosomiasis is the major neglected tropical helminthic disease worldwide. Current knowledge on the epidemiology of schistosomiasis in Guinea-Bissau is scarce and regarding to the absence of Schistosoma haematobium (S.h.). Therefore, a pilot study was undertaken to assess the prevalence and morbidity due to S.h. infection in randomly selected 90 children and adolescents aged 6 to 15 years. Prevalence of S.h. infection was 20.00 % (18/90). Microhematuria was observed in 61.11 % (11/18) of S.h.-egg-excreting vs. 37.50 % (27/72) of non-S.h.-egg-excreting children p ≤ 0.01. Body mass index (BMI) was less than 15 kg/m(2) in 52/90 (57.78 %) of all children and adolescents, but this proportion increased to 66.67 % (12/18) in S.h.-infected children who were more frequently stunted and wasted than in non-infected children. The mean weight-for-age Z score (WAZ) was reduced in S.h. infected as compared to non-infected children (-1.48 ± 1.08 SD vs. -0.80 ± 1.11 SD; p ≤ 0.01). To our knowledge, this is the first epidemiologic report on S. haematobium infection in Guinea-Bissau since 22 years. Even in this relatively small study sample, it appears that S. haematobium, besides the well-known symptoms such as hematuria, leads to significant, albeit commonly unacknowledged morbidity such as stunting and wasting. These observations underscore the notion that this vulnerable but neglected population urgently needs to be targeted for implementation of measures for treatment and control.
- The new automated daily mortality surveillance system in PortugalPublication . Nogueira, P.J.; Machado, A.; Rodrigues, E.; Nunes, Baltazar; Sousa, L.; Jacinto, M.; Ferreira, A.; Falcão, J.M.; Ferrinho, P.The experience reported in an earlier Eurosurveillance issue on a fast method to evaluate the impact of the 2003 heatwave on mortality in Portugal, generated a daily mortality surveillance system (VDM) that has been operating ever since jointly with the Portuguese Heat Health Watch Warning System. This work describes the VDM system and how it evolved to become an automated system operating year-round, and shows briefly its potential using mortality data from January 2006 to June 2009 collected by the system itself. The new system has important advantages such as: rapid information acquisition, completeness (the entire population is included), lightness (very little information is exchanged, date of death, age, sex, place of death registration). It allows rapid detection of impacts (within five days) and allows a quick preliminary quantification of impacts that usually took several years to be done. These characteristics make this system a powerful tool for public health action. The VDM system also represents an example of inter-institutional cooperation, bringing together organisations from two different ministries, Health and Justice, aiming at improving knowledge about the mortality in the population.
- Urinary schistosomiasis in Guinea BissauPublication . Botelho, M.C.; Machado, A.; Carvalho, A.; Vilaça, M.; Conceição, O.; Alves, H.; Richter, J.; Bottazzi, M.E.; Bordalo, A.A.Urogenital schistosomiasis due to Schistosoma (S.) haematobium is among the most prevalent parasitoses in sub-Saharan Africa. The pathology is characterized by serious and irreversible lesions in the urogenital tract induced by chronic infection with the parasite that can eventually lead to renal failure due to hydronephrosis and to squamous cell carcinoma of the bladder. Considering the frequency and severe morbidity observed already in young children, the purpose of this pilot study was to assess the prevalence and morbidity of S. haematobium infection in Guinea Bissau. A baseline survey was conducted during September 2011. A randomly selected sample of 90 children aged 6–15 years old was included in this study. Prevalence of S. haematobium infection was 20% (18/90). It was higher in older children (median age in years: 15.4 2.71 vs. 9.3 2.22; P < 0.001), a significant gender difference in prevalence and intensity was not found. The predominant symptom was haematuria (87.1%), this symptom being strongly associated with S. haematobium infection (P < 0.01). Anthropometric examination revealed that growth in infected boys was impaired as compared to non-infected boys (median height in cm: 123.3 21.07 vs. 134.71 15.1) (P < 0.05). To our knowledge this is the first epidemiologic report of S. haematobium infection in Guinea Bissau. Considering the high prevalence of S. haematobium infections in Guinea Bissau and the long-term risks, including renal failure and bladder cancer, our results indicate that this population should be targeted for follow-up and implementation of measures for treatment and control of schistosomiasis.