Browsing by Author "Oliveira, Marta"
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- Acetyl-L-Carnitine Improves Cell BioenergeticsPublication . Cunha, Lídia; Bravo, Joana; Costa, Pedro; Fernandes, Sílvia; Oliveira, Marta; Castro, Rosa; Metello, Luís F.; Summavielle, TeresaIntroduction: Acetyl-L-Carnitine (ALC), a natural occurring compound in all mammalian species, plays a variety of vital functions in the body. The most important are related to mitochondria, namely the transport of fatty acids for energy production through β oxidation and the control of acyl-CoA/CoA ratio. Due to this close interaction with cell bioenergetics, it plays a role in many diseases, especially those related to the mitochondria. We propose to characterize the action of ALC in mitochondrial bioenergetics and functional integrity.
- Assessment of air quality in preschool environments (3-5 years old children) with emphasis on elemental composition of PM10 and PM2.5Publication . Oliveira, Marta; Slezakova, Klara; Delerue-Matos, Cristina; Pereira, Maria Carmo; Morais, SimoneThis study evaluated concentrations of main air pollutants in a Portuguese preschool (indoors/outdoors) environment, with emphasis on elemental characterization of different PM fractions, and estimated risks for the pupils (aged 3-5 years). With exception to total volatile organic compounds, levels of PM10, PM2.5, CO, CO2, and formaldehyde were below legislative guidelines. Calcium, sodium, aluminium, and potassium were the most abundant elements in indoor PM (82-84% of the analysed content) resulting mainly from crustal sources. Carcinogenic elements (1-2% of the indoor analysed content) were mostly PM2.5- bound (83-91%). Indoor-to-outdoor ratios of individual elements indicated contributions of indoor origin and from penetration of outdoor emissions indoors; trace metals were associated with ambient anthropogenic emissions (namely traffic). Non-carcinogenic and carcinogenic risks from overall preschool exposure were acceptable for children; for adults carcinogenic risks exceeded (4-11 times) the USEPA recommend value of 10-6, being 8-40 times higher than for children.
- Assessment of exposure to polycyclic aromatic hydrocarbons inpreschool children: Levels and impact of preschool indoor air onexcretion of main urinary monohydroxyl metabolitesPublication . Oliveira, Marta; Slezakova, Klara; Delerue-Matos, Cristina; Pereira, Maria do Carmo; Morais, SimoneThe present work aimed to assess exposure of preschool children to polycyclic aromatic hydrocar-bons (PAHs) by environmental monitoring (eighteen compounds in air) and biomonitoring (six urinary biomarkers of exposure (OH-PAHs)). The impact of preschool indoor air on excretion of urinary mono-hydroxyl metabolites was also evaluated. Gaseous and particulate-bound PAHs were simultaneously collected indoors and outdoors in two Portuguese preschools. PAHs and OH-PAHs were quantified by high-performance liquid chromatography with fluorescence and photodiode array detection. Total air (gaseous + total suspended particles) levels of PAHs (PAHs) were higher indoors than outdoors. Gaseous phase (composed by ≥98% of 2–3 rings compounds) and particulate-bound PAHs (90–99% of 5–6 rings) accounted for 93–95% and 5–7% of PAHs in indoor air, respectively. Total (including probable/possible) carcinogenic PAHs represented 26–45% of PAHs; naphthalene and dibenz[a,h]anthracene were the strongest contributors. A similar distribution profile was observed between airborne PAHs and uri-nary OH-PAHs. Urinary 1-hydroxynaphthalene + 1-hydroxyacenaphthene represented more than 78%of OH-PAHs, being followed by 2-hydroxyfluorene, 1-hydroxypyrene, and 1-hydroxyphenanthrene. 3-hydroxybenzo[a]pyrene (PAH biomarker of carcinogenicity) was not detected. Results suggest that children had preschool indoor air as their major exposure source of naphthalene and acenaphthene, while no conclusion was reached regarding fluorene, phenanthrene and pyrene.
- Assessment of polycyclic aromatic hydrocarbons in indoor and outdoor air of preschool environments (3–5 years old children)Publication . Oliveira, Marta; Slezakova, Klara; Delerue-Matos, Cristina; Pereira, Maria do Carmo; Morais, SimoneThis work characterizes levels of polycyclic aromatic hydrocarbons (PAHs) in indoor and outdoor air of preschool environments, and assesses the respective risks for 3–5-years old children. Eighteen gaseous and particulate (PM1 and PM2.5) PAHs were collected indoors and outdoors during 63 days at preschools in Portugal. Gaseous PAHs accounted for 94–98% of total concentration (ΣPAHs). PAHs with 5–6 rings were predominantly found in PM1 (54–74% particulate ΣPAHs). Lighter PAHs originated mainly from indoor sources whereas congeners with 4–6 rings resulted mostly from outdoor emissions penetration (motor vehicle, fuel burning). Total cancer risks of children were negligible according to USEPA, but exceeded (8–13 times) WHO health-based guideline. Carcinogenic risks due to indoor exposure were higher than for outdoors (4–18 times).
- Barbecue Grill Workers Occupational Exposure to Particulate-Bound Polycyclic Aromatic HydrocarbonsPublication . Oliveira, Marta; Capelas, Sílvia; Delerue-Matos, Cristina; Pereira, Isabel; Morais, SimoneDuring a regular working day, grill workers are exposed to the emissions of charcoal-fired cooking activities, which include polycyclic aromatic hydrocarbons (PAHs) that are among the most health relevant compounds. Thus, in this work, the particulate matter at the breathing air zone of grill workers from a barbecue restaurant was sampled and the concentration of eighteen particulate-bound PAHs was determined by liquid chromatography with fluorescence and diode array detection. Median level of total PAHs (ΣPAHs) during 5 consecutive hours of exposure to barbecue fumes was 77.2 ng/m3 (maximum values of 261 ng/m3). Benzo(g,h,i)perylene, phenanthrene, and acenaphthylene were the most abundant compounds (82.7% of ΣPAHs). Levels of benzo(a)pyrene and total carcinogenic PAHs (naphthalene, benz(a)anthracene, benzo(b)fluoranthene, benzo(j)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, chrysene, and indeno(1,2,3-cd)pyrene) varied between 0.03–0.79 ng/m3 and 2.10–36.7 ng/m3, respectively. Grill worker’s exposure to PAHs was well below the existent PAHs occupational threshold limit value of 200 µg/m3 proposed by the American Conference of Governmental Industrial Hygienists for an 8-h of exposure to coal tar pitch volatiles. Some preventive measures such as adequate maintenance of barbecue ventilation system, regular wash of workers exposed skin and the use of clean working clothes can contribute to reduce grill worker’s occupational exposure to PAHs.
- Biomonitoring of firefighting forces: a review on biomarkers of exposure to health-relevant pollutants released from firesPublication . Barros, Bela; Oliveira, Marta; Morais, SimoneOccupational exposure as a firefighter has recently been classified as a carcinogen to humans by International Agency for Research on Cancer (IARC). Biomonitoring has been increasingly used to characterize exposure of firefighting forces to contaminants. However, available data are dispersed and information on the most relevant and promising biomarkers in this context of firefighting is missing. This review presents a comprehensive summary and critical appraisal of existing biomar-kers of exposure including volatile organic compounds such as polycyclic aromatic hydrocarbons, several other persistent other organic pollutants as well as heavy metals and metalloids detected in biological fluids of firefighters attending different fire scenarios. Urine was the most characterized matrix, followed by blood. Firefighters exhaled breath and saliva were poorly evaluated. Overall, biological levels of compounds were predominantly increased in firefighters after participation in firefighting activities. Biomonitoring studies combining different biomarkers of exposure and of effect are currently limited but exploratory findings are of high interest. However, biomonitoring still has some unresolved major limitations since reference or recommended values are not yet established for most biomarkers. In addition, half-lives values for most of the biomarkers have thus far not been defined, which significantly hampers the design of studies. These limitations need to be tackled urgently to improve risk assessment and support implementation of better more effective preventive strategies.
- Children environmental exposure to particulate matter and polycyclic aromatic hydrocarbons and biomonitoring in school environments: A review on indoor and outdoor exposure levels, major sources and health impactsPublication . Oliveira, Marta; Slezakova, Klara; Delerue-Matos, Cristina; Pereira, Maria Carmo; Morais, SimoneChildren, an important vulnerable group, spend most of their time at schools (up to 10 h per day, mostly indoors) and the respective air quality may significantly impact on children health. Thus, this work reviews the published studies on children biomonitoring and environmental exposure to particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) at school microenvironments (indoors and outdoors), major sources and potential health risks. A total of 28, 35, and 31% of the studies reported levels that exceeded the international outdoor ambient air guidelines for PM10, PM2.5, and benzo(a)pyrene, respectively. Indoor and outdoor concentrations of PM10 at European schools, the most characterized continent, ranged between 7.5 and 229 μg/m3 and 21-166 μg/m3, respectively; levels of PM2.5 varied between 4 and 100 μg/m3 indoors and 6.1-115 μg/m3 outdoors. Despite scarce information in some geographical regions (America, Oceania and Africa), the collected data clearly show that Asian children are exposed to the highest concentrations of PM and PAHs at school environments, which were associated with increased carcinogenic risks and with the highest values of urinary total monohydroxyl PAH metabolites (PAH biomarkers of exposure). Additionally, children attending schools in polluted urban and industrial areas are exposed to higher levels of PM and PAHs with increased concentrations of urinary PAH metabolites in comparison with children from rural areas. Strong evidences demonstrated associations between environmental exposure to PM and PAHs with several health outcomes, including increased risk of asthma, pulmonary infections, skin diseases, and allergies. Nevertheless, there is a scientific gap on studies that include the characterization of PM fine fraction and the levels of PAHs in the total air (particulate and gas phases) of indoor and outdoor air of school environments and the associated risks for the health of children. There is a clear need to improve indoor air quality in schools and to establish international guidelines for exposure limits in these environments.
- Commercial octopus species from different geographical origins: Levels of polycyclic aromatic hydrocarbons and potential health risks for consumersPublication . Oliveira, Marta; Gomes, Filipa; Torrinha, Álvaro; Ramalhosa, Maria João; Delerue-Matos, Cristina; Morais, SimonePolycyclic aromatic hydrocarbons (PAHs) are persistent pollutants that have been raising global concern due to their carcinogenic and mutagenic properties. A total of 18 PAHs (16 USEPA priority compounds, benzo(j)fluoranthene and dibenzo(a,l)pyrene) were assessed in the edible tissues of raw octopus (Octopus vulgaris, Octopus maya, and Eledone cirrhosa) from six geographical origins available to Portuguese consumers. Inter- and intra-species comparison was statistically performed. The concentrations of total PAHs (∑PAHs) ranged between 8.59 and 12.8 μg/kg w.w. Octopus vulgaris caught in northwest Atlantic Ocean presented ΣPAHs significantly higher than those captured in Pacific Ocean and Mediterranean Sea, as well as than the other characterized species from western central and northeast Atlantic Ocean. PAHs with 2-3 rings were the predominant compounds (86-92% of ∑PAHs) but diagnostic ratios indicated the existence of pyrogenic sources in addition to petrogenic sources. Known and possible/probable carcinogenic compounds represented 11-21% of ΣPAHs. World and Portuguese per capita ingestion of ∑PAHs due to cephalopods consumption varied between 1.62-2.55 × 10-4 and 7.09-11.2 × 10-4 μg/kg body weight per day, respectively. Potential risks estimated for low and high consumers according to USEPA methodology suggested that a regular consumption of raw octopus does not pose public health risks.
- Determination of the radiochemical purity of 99mTc-Tetrofosmin: comparision between five methodsPublication . Aguiar, Ana; Oliveira, Marta; Teixeira, Dalila; Cunha, Lídia; Metello, Luís F.GOAL: The manufacturing and distribution of strips of instant thin - layer chromatography with silica gel (ITLC - SG) (reference method) is currently discontinued so there is a need for an alternative method f or the determination of radiochemical purity (RCP) of 99m Tc - tetrofosmin. This study aims to compare five alternative methods proposed by the producer to determine the RCP of 99m Tc - tetrofosmin. METHODS: Nineteen vials of tetrofosmin were radiolabelled with 99m Tc and the percentages of the RCP were determined. Five different methods were compared with the standard RCP testing method (ITLC - SG, 2x20 cm): Whatman 3MM (1x10 cm) with acetone and dichloro - methane (method 1); Whatman 3MM (1x1 0 cm) with ethyl acetate (method 2); aluminum oxide - coated plastic thin - layer chromatography (TLC) plate (1x10 cm) and ethanol (method 3); Whatman 3MM (2x20 cm) with acetone and dichloro - methane (method 4); solid - phase extraction method C18 cartridge (meth od 5). RESULTS: The average values of RCP were 95,30% ± 1,28% (method 1), 93,95 ± 0,61% (method 2), 96,85% ± 0,93% (method 3), 92,94% ± 0,99% (method 4) and 96,25% ± 2,57% (method 5) (n=12 each), and 93,15% ± 1,13% for the standard method (n=19). There we re statistical significant differences in the values obtained for methods 1 (P=0,001), 3 (P=0,000) and 5 (P=0,004), and there were no statistical significant differences in the values obtained for methods 2 (P=0,113) and 4 (P=0,327). CONCLUSION: From the results obtained, methods 2 and 4 showed a higher correlation with the standard method. Unlike method 4, method 2 is less time - consuming than the reference method and can overcome the problems associated with the solvent toxicity. The remaining methods (1, 3 and 5) tended to overestimate RCP value compared to the standard method.
- Development of polyaniline microarray electrodes for cadmium analysisPublication . Oliveira, Marta; Viswanathan, Subramanian; Morais, Simone; Delerue-Matos, CristinaDisposable screen-printed electrodes (SPCE) were modified using a cosmetic product to partially block the electrode surface in order to obtain a microelectrode array. The microarrays formed were electropolymerized with aniline. Scanning electron microscopy was used to evaluate the modified and polymerized electrode surface. Electrochemical characteristics of the constructed sensor for cadmium analysis were evaluated by cyclic and square-wave voltammetry. Optimized stripping procedure in which the preconcentration of cadmium was achieved by depositing at –1.20 V (vs. Ag/AgCl) resulted in a well defined anodic peak at approximately –0.7 V at pH 4.6. The achieved limit of detection was 4 × 10−9 mol dm−3. Spray modified and polymerized microarray electrodes were successfully applied to quantify cadmium in fish sample digests.