Percorrer por autor "Matos, A."
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- Analysis and Identification of Trihalomethanes in Lisbon Indoor Swimming Pools: Distribution, Determinants and Human ExposurePublication . Silva, Z.; Rebelo, H.; Silva, M.M.; Alves, A.; Cabral, C.; Almeida, A.C.; Aguiar, F.; Oliveira, A.; Nogueira, A.; Pinhal, H.; Matos, A.; Ramos, C.D.; Pacheco, P.; Aguiar, P.; Cardoso, A.S.Water disinfection methods are used in swimming pools to ensure an effective protection of users against microbiological pathogens, being chlorination the most common disinfection method used worldwide. The use of chlorine based treatment techniques has one strong drawback, which is the generation of disinfection by-products (DBPs), potentially harmful products that have been associated with respiratory and ocular symptoms, bladder cancer and adverse reproductive effects. Amongst DBPs, the most better characterized are trihalomethanes (THMs): chloroform (CF), bromoform (BF), bromodichloromethane (BDCM), and chlorodibromomethane (DBCM). In Portugal a specific legislation to assess the quality of swimming pools is inexistent. The guideline value used to evaluate total THMs in water (TTHMsW) is the one established in the Law 306/2007 - 100 μg/L. Some other water/air parameters were assessed by Law 5/97, WHO guidelines for safe recreational water environments (2006) and Standard 62.1 (2006) from American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASRHAE). The main goal of this investigation was to study the occurrence, distribution and determinants of THMs in indoor swimming pools. This will also enable an evaluation of the exposure of users to THMs. In order to achieve this goals, the characterization of water quality in 30 Lisbon indoor swimming pools, using chorine based treatment techniques, was made during a six month period. Several parameters such as TTHMs, CF, BDCM, DBCM, BF levels in water, free residual chlorine (FrCl), pH, TW, Tair, Hu, chemical oxygen demand (COD), and other, were determined in each pool, once a month. Statistical analysis was performed using the SPSS 17.0 software. Descriptive analysis was applied to all variables. Student’s t-test, Mann-Whitney tests and Spearman’s rank correlation coefficient were also used. Large variation in TTHMs and CF water levels between the pools was obtained, being CF the THM obtained in higher concentrations, with sporadic higher values than the allowed. In air, CF level (CFair) also presented occasional higher levels. There was a clear positive linear correlation between CFW and TTHMsW (R>0.95, p<0.01), CFW and CFair (R> 0.5; p<0.05), CFW and FrCl (R>0.2; p<0.05) and, CFw and Tw (R>0.2; p<0.05). Good correlations were also obtained between other THMs: BDCM and DBCM (R>0.5, p<0.01) and BF and DBCM (R>0.6; p<0.05). The strong positive correlation obtained between CFW and TTHMsW was expected, since, usually, CFW has the higher contribution to TTHMsW. CFW is often considered as a good indicator of TTHMs concentration in water. Therefore correlations between TTHMs and CFair, FrCl, and Tw were expected and observed: TTHMsW vs CFair (R>0.5; p<0.05), TTHMsW vs FrCl (R>0.2; p<0.05) and TTHMsW vs TW (R>0.2; p<0.01). In conclusion, reasonable water and air quality was obtained in the studied Lisbon swimming pools, although some pools presented high TTHMsW, CFW and CFair. These results clearly demonstrate that THMs monitoring is particularly important and that, in a near future, this should be extended to other DBPs. Furthermore, for conscious use of swimming pools, appropriate and targeted information about safe practices should be provided to pool users.
- Building a database for provenance studies of origin wines from the Douro ValleyPublication . Coelho, I.; Matos, A.; Nascimento, A.; Bordado, J.; Donard, O.; Epova, E.; Barre, J.; Berail, S.; Castanheira, I.AIM: The aim of the present work is to produce high quality analytical data suitable for evaluating the provenance of Port wine and Douro wine and integrating an authentic wine reference database. Both wines are produced within the same geographical area, the Douro Valley region located in the northeast of Portugal but follow different vinification procedures. The fermentation of Port wine is interrupted by the addition of a grape based spirit producing a sweet fortified wine typically consumed as digestif and dessert wine. Douro wine, on the other hand, is a table wine. The mineral composition of plants reflects the soil and the environmental conditions under which plants were grown. Minerals and trace elements, as well as some of their isotopes, are potential biomarkers in authenticity studies. We followed two analytical strategies, multielemental analysis and stable isotopes, to understand the parameters common to the region and fundamentally dependent on the soils and the ones influenced by processing methods or environmental contamination. MATERIAL AND METHODS: Fifteen samples of each type of wine, Port and Douro, were characterized for 26 elements. 7Li, 9Be, 11B, 27Al, 52Cr, 55Mn, 59Co, 60Ni, 65Cu, 66Zn, 75As, 77Se, 85Rb, 88Sr, 95Mo, 107Ag, 111Cd, 118Sn, 205Tl, 208Pb were determined by inductively coupled plasma mass spectrometer (ICP-MS) while Fe, Mg , P , Ca , Na , K were analysed by inductively coupled plasma optical emission spectrometer (ICP-OES). In addition, two isotopic systems were also studied: 87Sr/86Sr and 18O determined by Multicollector-ICP-MS (MC-ICP-MS) and Isotope Ratios Mass Spectrometry (IRMS), respectively. For all analysis reagents used were of high purity to prevent for contaminations. Ultra pure water of grade I, as defined in EN ISO 3696, was obtained using a Milli-Q plus Millipore System. Concentrated nitric acid, analytical grade (65%; Merck), was purified in the laboratory, using an acid distillation system (Milestone SubPUR), and compared to a commercial ultrapure nitric acid solution (Merck), on a routine basis. Analytical results were combined with chemometric tools, Principal Components Analysis (PCA) and Hierarchical Cluster Analysis (HCA), capable of performing multivariate data analysis. RESULTS: Ag, Cd and Tl were mostly below the level of quantification and were therefore removed from statistical analysis. 87Sr/86Sr varied between 0,71652 and 0,72290. PCA revealed 6 principal components that explained 84,6% of the total variance. CONCLUSIONS: The vinification method did not affect significantly stable isotopes, either 87Sr/86Sr or 18O. On the other hand, some elements; namely Cr, Co, Cu, Rb, Se, Ca and Na; showed significant differences between the two types of wine. The produced data can be integrated into an authenticity system for Port and Douro wines.
- Development and Characterization of Engineered Acrylic Particulate SystemsPublication . Graça, Diogo; Ferreira, I.S.F.; Matos, A.; Gonçalves, L.M.D.; Silva, M.J.; Almeida, A.J.; Bettencourt, A.Polymethylmethacrylate (PMMA) is one of the most widely explored biomaterials because of its biocompatibility. Recent publications have shown an increasing interest in its application as a carrier system in drug delivery[1]. A major drawback in its use refers to the incomplete drug release from PMMA particles. To improve release profiles, recent strategies are focusing on formulating PMMA composites with permeable polymers. The main aim of the study was to evaluate the effect of the incorporation of a specific permeable polymer - an Eudragit polymer (EUD) - to PMMA particles. Both PMMA and PMMA-EUD particles were obtained through simple emulsion solvent evaporation methodology (SESE), previously optimized in our group[1]. Comparison between particles was mainly focused on physicochemical properties with impact on drug release, including particle size, surface charge, hydrophobicity and chemical composition, which were conducted using suitable methods such as laser diffraction, zeta potential, hydrophobic interaction chromatography (HIC), Fourier Transform Infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM). SESE methodology allowed the production of particles with spherical and smooth surfaces within the micrometer range (PMMA = 572.7 ± 20 nm; PMMA-EUD = 508.9 ± 8 nm) with unimodal and narrow size distribution. Surface charge modification, as measured through zeta potential, was the main feature observed after inclusion of EUD in the formulation. Initial PMMA particles were strongly negative (-32.9±1.4 mV) whereas PMMA-EUD particles were strongly positive (+33.7±4.4 mV). The formulated PMMA-EUD particles also have shown slightly higher levels of hidrophobicity than the PMMA particles. Protein adsorption was also studied using a model protein (bovine serum albumin) through UV-Vis spectroscopy with both types of particles showing no considerable adsorption. The next step will be the evaluation of the effect of PMMA particles composition change in the release of a model drug. References: [1] Bettencourt, A., Almeida, A.J., J Microencapsul., 2012, 29(4):353-67.
- Does surface charge play a role in nanoparticulate-systems toxicity?Publication . Bettencourt, A.; Graça, D.F.; Ferreira, IFS; Matos, A.; Louro, Henriqueta; Silva, Maria João; Almeida, A.J.; Gonçalves, L.M.The aim of the present work was to compare the toxicity of relevant biomedical acrylic based particulate systems (polymethylmethacrylate – PMMA), with different charges, within the same size range (500nm). Specifically, PMMA (negatively charged) and PMMA-Eudragit (positively charged) formulations were considered.
- Safety assessment of poly(methylmethacrylate) nanomaterials for drug delivery: genotoxicity in mammalian cellsPublication . Bettencourt, Ana; Graça, DIogo; Matos, A.; Ferreira, I.; Almeida, A.; Gonçalves, L.; Santos, Joana; Louro, Henriqueta; Silva, Maria JoãoThe application of nanomaterials (NMs) as carriers for drug delivery is seen as a key factor in innovative medicine products. A major class of drug controlled release systems includes polymeric NMs, due to their unique physicochemical properties that can be manipulated using well-established techniques. Among these, polymethylmethacrylate (PMMA) is a biomedical polymer with increasing interest as a carrier system of many drugs, e.g. antibiotics, for in situ therapy. However, the same unique properties that render these NMs so valuable may underlie unforeseen toxicological adverse side effects that must be assessed prior to their application. A major concern is their long-term effects, particularly, their potential genotoxicity, given that may persist in the human body. The present work aimed at synthesizing PMMA particles for drug delivery and assessing their safety through in vitro genotoxicity testing. PMMA particles were prepared by double emulsion-solvent-evaporation methodology and the relevant properties concerning their nano-biological interactions namely, size distribution, zeta potential and hydrophobicity were measured. As part of their safety assessment the cytotoxicity (MTT test) and genotoxicity (comet and micronucleus assays) were characterized using murine L929 fibroblasts. The results showed an absence of cytotoxicity and genotoxicity. In fact, neither DNA damage nor oxidative DNA damage was detected by the comet and FPG-modified comet assay, respectively. Furthermore, no clastogenicity/aneugenicity was observed by the micronucleus assay up to 5 mg/mL (OECD-TG 487 guideline). Further studies, including in vivo mutagenicity testing, are desirable for assuring the safe use of this NM.
- The effect of glutathione S-transferase M1 and T1 polymorphisms on ascorbic acid plasma levels in diabetic patientsPublication . Valente, A.; Bicho, M.; Santos, A.C.; Matos, A.; Duarte, R.; Raposo, J.F.; Costa, H.S.Introduction: Type 2 diabetes mellitus have been associated with excessive production of reactive oxygen species. Glutathione S-transferase (GST) polymorphisms result in decreased or absent enzyme activity and altered oxidative stress. Meta-analyses have indicated that deletion of either GSTM1 or GSTT1 is associated with a significant increased risk of coronary heart disease. The aim of this study was to evaluated if ascorbic acid (AA) plasma levels differ by GST genotype in diabetic patients with and without angiopathy. Methods: An observational analytical case-control study in 123 Caucasians type 2 diabetic patients was performed. GI - 65 diabetics with angiopathy, GII - 58 diabetics without angiopathy. Plasma levels of AA were measured by a validated HPLC method. The genotyping of GSTT1 and GSTM1 it was determined simultaneously by PCRMultiplex technique. Results: The frequency of GSTM1 and GSTT1 single-null genotypes was 42.9% and 30.8% in group I and 43.9% and 31.0% among in group II. The percentage of diabetics patients who had both GSTM1 and GSTT1 functional genotypes was GI:46.0% and GII:42.9%, who had one of the present genotypes was GI:33.4% and GII:37.5% and who had both null genotypes was GI:20.6% and GII:19.6%. Plasma AA concentrations were lower in those with the GSTT1 null genotype than in those with the GSTT1 functional genotype. GSTM1 null genotypes had higher plasma AA levels than those with functional GSTM1 allele. Suboptimal AA plasma concentrations (<4.93 μmol/L) were more frequent in GSTT1 deletion genotype (76.3%) compared to GSTT1-1 (69.4%). Inversely, the percentage of patients with functional GSTM1 allele (72.1%) was higher than null genotype (67.3%). Conclusion: Plasmatic levels of AA differ by GSTM1 and GSTT1 polymorphisms in Caucasians diabetic patients with or without angiopathy. The upper and lower regulation of AA plasma levels in subjects with nonfunctional GSTT1 or GSTM1 could be partially understood to compensate the lack of functionality.
- The occurrence of inorganic contaminants in ‘tronchuda’ cabbage (Brassica oleracea L. var. costata DC.) after large forest fires in PortugalPublication . Ventura, Marta; Cavaco, H.; Delgado, Inês; Coelho, Inês; Gueifão, Sandra; Martins, M.; Costa, M.H.; Matos, A.; Castanheira, IsabelEuropean Mediterranean countries have been affected by unhealthy pollutants released by wildfire smoke. This work aims to determine the inorganic elements, present in the vegetable widely consumed by the rural population, provided by burned areas. Two groups composed the sampling plan; group one before forest fires and group two after forest fires under three campaigns: 1) immediately after forest fires; 2) after rainfall; 3) during springtime. ICP-MS analysed all the samples to evaluate the contents of As, Br, Cd, Co, Cr, Pb, Se, Sr, and Zn. The amounts of trace elements founded were the following Pb < Cd < Co < As < Cr < Se < Zn < Br < Sr. Hierarchical Cluster Analysis evidenced 4 clusters; the first with the highest contents of Cr and Pb, the second cluster was marked by the highest amounts of As, and Br, higher values of Se characterised the third cluster, and the fourth cluster presented the highest values of Zn and Cd. The contents of contaminants in group one is not a matter of concern. The results obtained in group two identified a hazard, decreasing one year after the fires and maintaining these patterns afterwards. Occurrence data from local foods is a pioneer to study the impact of forest fires on human health through food consumption.
- Trihalomethanes in Lisbon Indoor Swimming Pools: Occurrence and Determining FactorsPublication . Silva, Z.; Rebelo, H.; Silva, M.M.; Alves, A.; Cabral, C.; Almeida, A.C.; Aguiar, F.; Oliveira, A.; Nogueira, A.; Pinhal, H.; Matos, A.; Ramos, C.D.; Pacheco, P.; Aguiar, P.; Cardoso, A.S.The presence of water disinfection by-products (DBPs) in swimming pools constitutes today a public health concern, particularly because swimming is an activity used by a high percentage of the population, namely elderly and young children. Moreover, several adverse short-term and long-term health effects have been associated with these compounds (Lakind et al., 2010; Zwiener et al., 2007). Water disinfection methods are used in all swimming pools, namely in public pools, to ensure an adequate and effective protection of users against microbiological pathogens. Chlorination is the most common disinfection method used worldwide, because it is low cost, easy to use, efficient against a broad spectrum of microorganisms, and enables the maintenance of a residual protection. The use of chlorine based treatment techniques has one strong drawback, which is the generation of several DBPs, potentially harmful products, that can be absorbed by ingestion, inhalation and absorption through the skin (Nieuwenhuijsen et al., 2009; Caro and Gallego, 2007). DBPs comprise several compounds that are formed through the reaction of chlorine with organic matter present in water. Amongst DBPs, the most relevant and better characterized are trihalomethanes (THMs): chloroform (CF), bromoform (BF), bromodichloromethane (BDCM), and chlorodibromomethane (DBCM). These compounds have been associated with health effects such as respiratory, ocular and cutaneous symptoms and also with some long-term health effects such as bladder cancer and adverse reproductive outcomes (Lee et al., 2009; Zwiener et al., 2007). Accurate exposure assessments to THMs in indoor pool environment is particularly difficult because their formation depends on many factors such as water and air temperature (Tw and Tair), humidity (Hu), pH, free residual chlorine (FrCl), total organic content and number of pool users (Lee et al., 2009). In Portugal a specific legislation to assess the quality of swimming pool waters is inexistent. The guideline value used in this study for total THMs (TTHMs) was the one established in the Portuguese Law 306/2007, for drinking water quality - 100 μg/L. Some other water parameters determined in swimming pools such as Tw turbidity (Turb), pH, FrCl, total residual chlorine, conductivity (Cond), permanganate index (COD) and isocyanuric acid were assessed by Portuguese Law 5/97, regarding technical and safety conditions of closed environments with water diversions. WHO guidelines for safe recreational water environments (2006) were also used to assess some water and air parameters in pools. Standard 62.1 (2006) from American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASRHAE) was also used to assess pool air parameters. The main goal of this investigation project was to study the occurrence, distribution and determinants of THMs in indoor swimming pools. This will enable an evaluation of swimming pool users’ exposure to THMs. In order to achieve this goal, the characterization of water quality of 30 Lisbon indoor swimming pools, using chorine based treatment techniques, was made during a six month period. Because of laboratory working restrictions, CF concentration in pool air was studied only in 6 swimming pools, at the same period. Several parameters such as TTHMs concentration, CF, BDCM, DBCM, BF concentration in water, FrCl, combined residual chlorine (CrCl), pH, Tw and Tair, Hu, COD, Cond, Turb and chloride (Cl) were determined in each pool, once a month. THMs water sampling was made in duplicates in two pool water spots, physicochemical parameters were determined in one of the THMs water sampling spots and THMs air sampling was made in two pool spots, considered to be representative of the swimming pool air. All sampling procedures were performed by specialized sampling technicians from Lisbon Health Centres Group (ACES). Statistical analysis was performed using the SPSS 17.0 software. Descriptive analysis was applied to all variables in order to determine mean, median, standard deviation, minimum and maximum. Student’s t-test and Mann-Whitney tests were used to compare numerical variables and Spearman’s rank correlation coefficient were used to examine correlation between all environmental parameters. TTHMs water level ranged from 10 to 160 μg/L, while CF water level typically ranged from 5 to 150 μg/L, with occasional higher levels detected. Regarding other THMs levels in pool water, BDCM ranged from 0.5 to 15 μg/L, DBCM from 0.4 to 10 μg/L and BF was obtained in concentrations less than 2 μg/L. Moreover, in some pools, DBCM and BF were not detected. From these results, it can be concluded that there was a large variation in TTHMs and CF water levels between the pools and that CF was the THM obtained in higher concentrations. These results are in agreement with studies presented by other authors (Lee et al., 2009; Chu and Nieuwenhuijsen, 2002). In air, CF level ranged from 40 to 200 μg/m3, with occasional higher levels detected. Tw presented less variation (27 to 31 ºC) than Tair (21 to 33 ºC), although sporadic higher values were found. FrCl and Cond presented higher values than the guidelines from DR 5/97 only in a small number of pools. Turb and COD values were within the guidelines from DR 5/97. pH varied from 7 to 8.5, with only a small number of pools having values higher than 7.8. As referred in WHO guidelines, pH should be maintained between 7.2 and 7.8 for chlorine disinfectants to ensure efficient disinfection. Using the statistical tests mentioned before, it was possible to obtain some interesting results. There was a clear positive linear correlation between CF water concentration (CFW) and TTHMs water concentration (R>0.98, p<0.01), good correlation other THMs, there was a clear positive linear correlation between BDCM and DBCM water concentration (R>0.78, p<0.01) and good correlation between TTHMs water concentration and Tw (R>0.45, p<0.05). These results are in agreement with Lee et al. (2009) which obtained positive linear correlations between CFW and COD and with Chu and Nieuwenhuijsen (2002) which also obtained correlations between TTHMs water concentration and Tw. In conclusion, there appears to be good water and air quality in the studied Lisbon swimming pools. Regarding THMs levels in water, some pools presented high TTHMs and CF concentrations. Moreover, CF air concentrations were also high in some swimming pools. These results clearly demonstrate that THMs monitoring is particularly important and that, in a near future, this should be extended to other DBPs. Furthermore, for a correct and conscious use of swimming pools, appropriate and targeted information about safe practices should be provided to pool users.