Browsing by Author "Mayan, Olga"
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- Assessment of immunotoxicity parameters in individuals occupationally exposed to leadPublication . García-Lestón, Julia; Roma-Torres, Joana; Mayan, Olga; Schroecksnadel, Sebastian; Fuchs, Dietmar; Moreira, Ana; Pásaro, Eduardo; Méndez, Josefina; Teixeira, João Paulo; Laffon, BlancaAlthough adverse health effects produced by lead (Pb) have long been recognized, studies regarding the immunotoxic effects of occupational exposure report conflicting results. In a previous study, alterations in some immunological parameters were noted in 70 Pb-exposed workers. In view of these results, it was of interest to extend this study comprising a larger population and increasing the number of immunological endpoints assessed. Accordingly, in this study the immunotoxic effects of occupational exposure to Pb were assessed by analyzing (1) percentages of lymphocyte subsets (CD3⁺, CD4⁺, CD8⁺, CD19⁺, and CD56⁺/16⁺); (2) concentration of plasma cytokines, namely, interleukin (IL) 2, IL4, IL6, IL10, tumor necrosis factor (TNF) α, and interferon (IFN) γ; and (3) plasma concentrations of neopterin, tryptophan (Trp), and kynurenine (Kyn). In addition, the possible influence of genetic polymorphisms in the vitamin D receptor (VDR) and δ-aminolevulinic acid dehydratase (ALAD) genes on immunotoxicity parameters was studied. Exposed workers showed significant decreases in %CD3⁺, %CD4⁺/%CD8⁺ ratio, IL4, TNFα, IFNγ, and Kyn to Trp ratio (Kyn/Trp), and significant increases in %CD8⁺, IL10, and Trp levels. All these parameters, except Trp, were significantly correlated with exposure biomarkers. No significant influence of genetic polymorphisms was observed. Significant correlation between Kyn/Trp and neopterin concentrations suggests an involvement of indoleamine 2,3-dioxygenase in the Trp metabolic alterations, which may contribute to some of the immune alterations observed. Results obtained suggest that occupational exposure to PB may influence the immune system by impairing several mechanisms, which might ultimately produce deregulation of the immune response and diminish immunosurveillance in exposed individuals.
- Evaluation of the Indoor Air Quality in Restaurants Before and After a Smoking Ban in PortugalPublication . Madureira, Joana; Mendes, Ana; Santos, Helder; Vilaça, Jorge; Neves, Maria Paula; Mayan, Olga; Teixeira, João PauloOn 14th August 2007, Portugal instituted a smoking ban in most indoor public places. The goal of this work was to quantify the effects of this ban on indoor air quality (IAQ) in Portuguese restaurants. Ten restaurants were investigated before and after the ban and the following indoor parameters measured: respirable suspended particulate matter (RSP), total volatile organic compounds (TVOC), benzene (C6H6), carbon monoxide (CO), carbon dioxide (CO2), temperature and relative humidity. Results show a statistically significant decrease in RSP and CO concentrations after the ban, as well as for TVOC and benzene concentrations. Additionally, the monitored CO2 concentrations widely exceeded 1800 mg·m-3 (reference for acceptable ventilation rates), suggesting inefficient ventilation of the indoor spaces. This paper provides the first comparison of IAQ in Portugal before and after the introduction of smoke-free law and these results confirm the positive impact of the law in the indoor air that became smoke-free after the legislation. This information should be provided to decision makers as it has significant health implications. This law thus appear to achieve the aim of protecting people from exposure to unwanted pollutants resulting from poor IAQ.
- Genotoxic effects of occupational exposure to lead and influence of polymorphisms in genes involved in lead toxicokinetics and in DNA repairPublication . García-Lestón, Julia; Roma-Torres, Joana; Vilares, Maria; Pinto, Rui; Prista, João; Teixeira, João Paulo; Mayan, Olga; Conde, Joao; Pingarilho, Marte; Gaspar, Jorge Francisco; Pásaro, Eduardo; Méndez, Josefina; Laffon, BlancaLead is still widely used in many industrial processes and is very persistent in the environment. Although toxic effects caused by occupational exposure to lead have been extensively studied, there are still conflicting results regarding its genotoxicity. In a previous pilot study we observed some genotoxic effects in a population of lead exposed workers. Thus, we extended our study analysing a larger population, increasing the number of genotoxicity endpoints, and including a set of 20 genetic polymorphisms related to lead toxicokinetics and DNA repair as susceptibility biomarkers. Our population comprised 148 workers from two Portuguese factories and 107 controls. The parameters analysed were: blood lead levels (BLL) and δ-aminolevulinic acid dehydratase (ALAD) activity as exposure biomarkers, and T-cell receptor (TCR) mutation assay, micronucleus (MN) test, comet assay and OGG1-modified comet assay as genotoxicity biomarkers. Lead exposed workers showed markedly higher BLL and lower ALAD activity than the controls, and significant increases of TCR mutation frequency (TCR-Mf), MN rate and DNA damage. Oxidative damage did not experience any significant alteration in the exposed population. Besides, significant influence was observed for VDR rs1544410 polymorphism on BLL; APE1 rs1130409 and LIG4 rs1805388 polymorphisms on TCR-Mf; MUTYH rs3219489, XRCC4 rs28360135 and LIG4 rs1805388 polymorphisms on comet assay parameter; and OGG1 rs1052133 and XRCC4 rs28360135 polymorphisms on oxidative damage. Our results showed genotoxic effects related to occupational lead exposure to levels under the Portuguese regulation limit of 70 μg/dl. Moreover, a significant influence of polymorphisms in genes involved in DNA repair on genotoxicity biomarkers was observed.