Percorrer por autor "Lage, Bruna"
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- Endotoxin levels in forklift’s filters and the importance of maintenance enforcementPublication . Pereira, Cristiana Costa; Lage, Bruna; Teixeira, João Paulo; Viegas, CarlaMany studies have already linked endotoxin exposure, especially in workplaces, to airways disease, yet threshold limit values have not been set, nor a standardized procedure for the analysis of endotoxin levels. Inhaled endotoxins may cause bronchial asthma and may increase the allergic response in hypersensitive people. Endotoxins are biologically active lipopolysaccharides (LPSs) produced by the most external layer of cellular walls of gram (−) bacteria. They are commonly found at workplaces where large amounts of bioaerosols are generated, like in waste sorting plants, where microorganisms growing on organic residue are present at high concentration in the air. Endotoxins are relatively heated stable so they are released into the air during cell growth and after cells’ death when the integrity of the cell wall is ruptured. Up to the present, endotoxin values are measured with non-uniform methods and therefore values are of limited benefit for assessment and limits’ establishment. In this study, eleven filters belonging to the filtration system from forklifts operating in one waste sorting industry located in the Lisbon region and one control filter were analyzed.
- Exposure assessment in one central hospital: a multi-approach protocol to achieve an accurate risk characterizationPublication . Viegas, Carla; Almeida, Beatriz; Monteiro, Ana; Paciência, Inês; Rufo, João; Aguiar, Lívia; Lage, Bruna; Diogo Gonçalves, Lídia Maria; Aranha Caetano, Liliana; Carolino, Elisabete; Gomes, Anita Quintal; Twarużek, Magdalena; Kosicki, Robert; Grajewski, Jan; Teixeira, João Paulo; Viegas, Susana; Pereira, CristianaThe bioburden in a Hospital building originates not only from patients, visitors and staff, but is also disseminated by several indoor hospital characteristics and outdoor environmental sources. This study intends to assess the exposure to bioburden in one central hospital with a multi-approach protocol using active and passive sampling methods. The microbial contamination was also characterized through molecular tools for toxigenic species, antifungal resistance and mycotoxins, and endotoxins profile. Two cytotoxicity assays (MTT and resazurin) were conducted with two cell lines (Calu-3 and THP-1), and in vitro pro-inflammatory potential was assessed in the THP-1 cell line. Out of the 15 sampling locations, 33.3% did not comply with Portuguese legislation regarding bacterial contamination, whereas concerning fungal contamination 60% presented I/O > 1. Toxigenic fungal species were observed in 27% of the sampled rooms (4 out of 15) and qPCR analysis successfully amplified DNA from the Aspergillus sections Flavi and Fumigati, although mycotoxins were not detected. Growth of distinct fungal species was observed on Sabouraud dextrose agar with triazole drugs, such as Aspergillus section Versicolores on 1 mg/L VORI. The highest concentrations of endotoxins were found in settled dust samples and ranged from 5.72 to 23.0 EU.mg−1. While a considerable cytotoxic effect (cell viability < 30%) was observed in one HVAC filter sample with the Calu-3 cell line, it was not observed with the THP-1 cell line. In air samples, a medium cytotoxic effect (61–68% cell viability) was observed in 3 out of 15 samples. The cytokine responses produced a more potent average cell response (46.8 ± 12.3 ρg/mL IL-1β; 90.8 ± 58.5 ρg/mL TNF-α) on passive samples than air samples (25.5 ± 5.2 ρg/mL IL-1β and of 19.4 ± 5.2 ρg/mL TNF-α). A multi-approach regarding parameters to assess, sampling, and analysis methods should be followed to characterize the bioburden in the hospital indoor environment. This study supports the importance of considering exposure to complex mixtures in indoor environments.
- Occupational exposure to endotoxins: forklift driversPublication . Costa-Pereira, Cristiana; Lage, Bruna; Viegas, Carla; Teixeira, João PauloMany studies have already associated endotoxin exposure, especially in workplaces, to airways disease, yet threshold limit values have not been set, nor a standardized procedure for the analysis of endotoxin levels. Inhaled endotoxins may cause bronchial asthma and may increase the allergic response in hypersensitive people. Endotoxins are biologically active lipopolysaccharides (LPSs) produced by the most external layer of cell walls of gram (−) bacteria. They are commonly found at workplaces where large amounts of bioaerosols are generated, like in waste sorting plants, where microorganisms growing on organic residue are present at high concentration in the air. Endotoxins are relatively heating stable so they are released into the air during cell growth and after cells’ death when the integrity of the cell wall is ruptured. Up to the present, endotoxin values are measured with non-uniform methods and therefore values are of limited benefit for assessment and limits’ establishment. In this study, eleven filters belonging to the filtration system from forklifts operating in one waste sorting industry located in the Lisbon region and one control filter were analyzed. The 11 filters were used in forklifts between 794 and 22,240 working h. All the assessed filters were composed by activated charcoal and belong to category 2 (pores typically from 3.0 μm or greater dimension) according to protection requirements (EN 15695) ensuring protection against dust inside the cabinet. In these settings, criteria for filter replacement in the air conditioning system are dependent on visual observation by the maintenance service to accomplish preventive maintenance program. Endotoxins levels were analyzed following the European Standard (2003) EN 14031 and varied between 3,6 EU/cm2 and > 625 EU/cm2. Considering that standard filters have an area of about 1226 cm2, the total charge of endotoxins in the studied filters ranges from 4382 EU to 766 250 EU which raises questions about the security and for how long is safe to keep the filters in use in this and other particular indoor settings.