Browsing by Author "Amaro, Raquel"
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- Characterization of fungal community associated with house dustPublication . Amaro, Raquel; Sousa, Ana Catarina Almeida; Barroso, Carlos Miguel MiguezWith the increasing urbanization, the world population spends more and more time indoors, where exposure to contaminants inside buildings can be high. This scenario leads to a degradation of Indoor Air Quality (IAQ), which, in extreme cases, can lead to Sick Building Syndrome (SBS). Fungi can be found in all types of environments and the fungal community found inside buildings plays an essential role in the health of individuals that use these locations. Dust in particular, acts as a reservoir of all contaminants inside buildings, including fungi and can be used to characterize the indoor environment. The coexistence of individuals with the fungi in the interior of a building is not always beneficial to health. There are strong associations between the patients with respiratory allergies and sensitization to molds where the latter play an important role in the development, persistence and severity of the former. For this type of immunologically susceptible individuals, exposure to fungal contamination can trigger respiratory symptoms such as asthma. Thus, this work aims in a first stage to characterize the fungal community in house dust samples from houses built along different decades using different dust sampling procedures and in a second stage to characterize the fungal community in dust from the houses of asthmatic patients and respective controls in order to unravel possible associations. This work was divided into two key points: i) to identify the fungal community in house dust and its abundance ii) to associate the fungal genera found with the severity of asthma. The most abundant fungal genera found were Aspergillus, Penicillium, Cladosporium, Alternaria and yeast. As for the association to asthma exacerbations, no association was found. However, given the preliminary nature of point ii), a larger number of samples will be necessary in order to draw any robust conclusions.
- Genetic damage in young swimmers exposed to pool disinfection by-productsPublication . Amaro, Raquel; Esteves, Filipa; Silva, Susana; Costa, Carla; Costa, Solange; Teixeira, João PauloIntroduction. Swimming is seen as an activity with innumerous wellbeing and health benefits. For the maintenance of the quality of swimming pools’ water, and consequently for the safety of its users, there is a need to add disinfection products. The interaction between these products and organic matter, naturally introduced in the water by users, leads to the formation of disinfection by-products (DBPs), many of them with mutagenic and carcinogenic characteristics. Younger individuals constitute a susceptible group and their exposure to genotoxic compounds may lead to health problems later in life. Despite the relevance of this issue in public health, there is limited research on the subject. The aim of this study was to evaluate genetic damage levels in young federated swimmers exposed to pool DBPs.
- House dust fungal communities’ characterization: a double take on the six by sixty by six (6 × 60 × 6) projectPublication . Amaro, Raquel; Coelho, Sónia D.; Pastorinho, M. Ramiro; Taborda-Barata, Luís; Vaz-Patto, Maria A.; Monteiro, Marisa; Nepomuceno, Miguel C.S.; Lanzinha, Joăo C.G.; Teixeira, Joăo P.; Pereira, Cristiana C.; Sousa, Ana C.A.Fungi are a group of microbes that are found with particular incidence in the indoor environment. Their direct toxicity or capability of generating toxic compounds has been associated with a large number of adverse health effects, such as infectious diseases and allergies. Given that in modern society people spend a large part of their time indoors; fungal communities’ characterization of this environmental compartment assumes paramount importance in the comprehension of health effects. House dust
- House dust fungal communities’ characterization: a double take on the six by sixty by six project (6x60x6)Publication . Amaro, Raquel; Coelho, Sónia; Pastorinho, M Ramiro; Taborda-Barata, Luís; Vaz-Pato, Maria Assunção; Monteiro, Marisa; Nepomuceno, Miguel; Lanzinha, João C. G.; Teixeira, João Paulo; Pereira, Cristiana C.; Sousa, Ana C. A.Background and objective(s): Fungi are a group microbes that are found with particular incidence in the indoor environment. Their direct toxicity or capability of generating toxic compounds has been associated with a large number of adverse health effects, such as infectious diseases, allergies and other toxic effects. House dust is a time integrative matrix easy to obtain and have been recommended for epidemiological studies on human exposure to environmental contaminants. This study aims to quantify and identify the fungal community on house dust samples collected using two different methodologies: active and passive sampling.
- Human Exposure to Disinfection By-Products in Indoor Swimming Pools: Looking at the Genotoxic EffectsPublication . Esteves, Filipa; Amaro, Raquel; Silva, Susana; Costa, Carla; Costa, Solange; Teixeira, João PauloDisinfection of pool water is an extremely important process that ensures the safety of its use avoiding water-borne infections caused by microbial pathogens. However, the chlorine used as disinfectant, in the presence of organic matter, may generate disinfection by-products (DBPs), including trihalomethanes (THMs), a class that includes genotoxic compounds, which are inhaled and absorbed by the skin. Previous studies have shown that exposure to these DBPs are associated with adverse health outcomes. The aim of this study was to assess DNA damage in swimming pool users exposed to THMs. To evaluate DNA damage, blood samples were collected from a group of approximately 150 swimmers in different indoor chlorinated pools located in north of Portugal. Levels of DNA strand breaks and oxidized purines (formamidopyrimidine DNA glycolase) sites were determined in lymphocytes using the comet assay. Individual exposure to THMs compounds was analysed using a predictive model; analysis included not only total THMs but also chloroform, dibromochloromethane, bromochloromethane and bromoform separately. Data obtained will increase knowledge on the potential genotoxic risks associated to THMs exposure in indoor swimming pools. Furthermore, results may be useful to perform a human health risk assessment model essential for development of risk management strategies.
- Optimizing Urine derived cells staining for the Human Micronucleus AssayPublication . Esteves, Filipa; Amaro, Raquel; Silva, Susana; Costa, Solange; Costa, Carla; Bolognesi, Claudia; Teixeira, João PauloEpidemiological studies commonly associate the incidence of cancers with the exposure to genotoxicants. This exposure may be analyzed using effect biomarkers allowing an early detection of health alterations. Micronucleus assay constitutes a useful tool to detect chromosomal damage, genomic instability and carcinogenic events. Cancers are usually from epithelial origin, and therefore micronucleus test (MN) in urine derived cells (UDC) assumes a great role on toxicological studies. Sampling of UDC is an easy and minimally invasive procedure, representing an advantage in human biomonitoring studies. The main concern related with UDC is the lack of standardization of MN protocol. Data show a large variability of the method, in particular what concerns to staining procedure, which may lead to bias. The use of different methodologies regarding MN in UDC may contribute to the large inter-laboratory variations and consequently for inconsistencies among studies. Aim: i) Select the most reliable method to stain UDC of those most commonly used - Giemsa and Feulgen. Giemsa - staining permits a quick preparation of slides for microscopic evaluation, however it is a non-DNA-specific stain which may favor false positive readings through the presence of other cellular structures (nonnuclear bodies, bacteria or keratohyalin granules). Feulgen - staining, although more time consuming, is a DNA specific stain which allows a good contrast between DNA material and cytoplasm; ii) Establish a detailed set of criteria for scoring all of the biomarkers in UDC; iii) Standardize the application of the mn assay in UDC.
- The impact of comet assay data normalization in human biomonitoring studies outcomesPublication . Esteves, Filipa; Amaro, Raquel; Silva, Susana; Sánchez-Flores, María; Teixeira, João Paulo; Costa, CarlaThe comet assay has been extensively used in biomonitoring studies. To avoid intra-experimental variability, the incorporation of assay controls in each work session for data normalization has been suggested by some authors but has never been thoroughly analyzed. The aim of this study was to address the impact of data normalization in the results of a biomonitoring study using different normalization models. Human peripheral blood mononuclear cells (PBMC) from 140 healthy individuals were analyzed using the alkaline and FPG-modified version of the comet assay across seven different work sessions. In addition to negative standards, methyl methanesulfonate (MMS) and Ro 19−8022 plus light treated PBMC, were also included in the assay as positive standards. To verify the impact of data normalization, some demographic, lifestyle and environmental exposure-related variables were selected. Significant associations with independent study variables were observed using normalized comet endpoints, as opposed to raw data. After normalization, levels of DNA strand breaks were significantly higher among males and older individuals (>71 years), while net FPG-sensitive sites were positively related to smoking habits and environmental exposures (i.e. air pollution and bottled water consumption). This study highlights how the normalization strategies can influence the statistical results of a human biomonitoring study and lead to different data interpretations.