Browsing by Issue Date, starting with "2023-05-26"
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- Visual comet scoring revisited: a guide to scoring comet assay slides and obtaining reliable resultsPublication . Møller, Peter; Azqueta, Amaya; Sanz-Serrano, Julen; Bakuradze, Tamara; Richling, Elke; Eyluel Bankoglu, Ezgi; Stopper, Helga; Claudino Bastos, Victoria; Langie, Sabine A.S.; Jensen, Annie; Scavone, Francesca; Giovannelli, Lisa; Wojewódzka, Maria; Kruszewski, Marcin; Valdiglesias, Vanessa; Laffon, Blanca; Costa, Carla; Costa, Solange; Teixeira, João Paulo; Marino, Mirko; Del Bo, Cristian; Riso, Patrizia; Zheng, Congying; Shaposhnikov, Sergey; Collins, AndrewMeasurement of DNA migration in the comet assay can be done by image analysis or visual scoring. The latter accounts for 20%-25% of the published comet assay results. Here we assess the intra- and inter-investigator variability in visual scoring of comets. We include three training sets of comet images, which can be used as reference for researchers who wish to use visual scoring of comets. Investigators in 11 different laboratories scored the comet images using a five-class scoring system. There is inter-investigator variation in the three training sets of comets (i.e. coefficient of variation (CV) = 9.7%, 19.8%, and 15.2% in training sets I-III, respectively). However, there is also a positive correlation of inter-investigator scoring in the three training sets (r = 0.60). Overall, 36% of the variation is attributed to inter-investigator variation and 64% stems from intra-investigator variation in scoring between comets (i.e. the comets in training sets I-III look slightly different and this gives rise to heterogeneity in scoring). Intra-investigator variation in scoring was also assessed by repeated analysis of the training sets by the same investigator. There was larger variation when the training sets were scored over a period of six months (CV = 5.9%-9.6%) as compared to 1 week (CV = 1.3%-6.1%). A subsequent study revealed a high inter-investigator variation when premade slides, prepared in a central laboratory, were stained and scored by investigators in different laboratories (CV = 105% and 18%-20% in premade slides with comets from unexposed and hydrogen peroxide-exposed cells, respectively). The results indicate that further standardization of visual scoring is desirable. Nevertheless, the analysis demonstrates that visual scoring is a reliable way of analysing DNA migration in comets.
- Assessing exposure to environmental contaminants in portuguese mother-infant pairs: the project ARTEMISPublication . Namorado, Sónia; Pastorinho, M. Ramiro; Simões, Mariana; Coelho, Susana; Lamy, Elsa; Silva, Susana Pereira; Ogura, Joana; Nunes, Baltazar; Sousa, Ana CatarinaObjective: Today chemicals play a major role in our daily lives, being present in the air we breathe, in the food we eat and in the products we use. As such, it is essential to know the levels of chemicals present in our bodies and assess the risks associated. For that, Human Biomonitoring (HBM), the measurement of the concentrations of chemicals in human biological samples, is a very useful technique. Nevertheless, Portuguese HBM data is scarce and more knowledge on the exposure to chemicals of the Portuguese population is needed. It is then proposed to develop a study to assess the current environmental exposure of Portuguese children and women of childbearing age, vulnerable groups of the population, to selected chemicals, particularly metals and endocrine disruptors. Methods: The project ARTEMIS will evaluate exposure of children aged 6-11 years old and their mothers aged 45 years or less residing in four selected rural and urban areas in Portugal (LVT and Alentejo regions). Recruitment will be done through schools. Urine and hair samples will be collected for the analysis of exposure biomarkers, namely of metals (including mercury, cadmium and arsenic), bisphenols and cotinine. Additionally, saliva samples will be collected for the analysis of effect biomarkers (salivary proteome). Questionnaire data on socio-demographic characteristics, lifestyle, nutrition, health, and specific information on exposure to the selected chemicals will be collected using CATI (Computer-Assisted Telephone Interviewing). A biobank will also be established to allow further analysis of the samples. Expected results: ARTEMIS will be an innovative project that will not only produce much needed data on the current exposure of the Portuguese population to chemicals, but also allow to evaluate time trends of exposure to some chemicals by comparison with the results from previous projects and to study the association of exposure with biomarkers of effect.
- The potential role of scavenging flies as mechanical vectors of Lagovirus europaeus/GI.2Publication . Lopes, Ana M.; Almeida, Tereza; Osório, HugoThe European rabbit (Oryctolagus cuniculus) populations of the Iberian Peninsula have been severely affected by the emergence of the rabbit haemorrhagic disease virus (RHDV) Lagovirus europaeus/GI.2 (RHDV2/b). Bushflies and blowflies (Muscidae and Calliphoridae families, respectively) are important RHDV vectors in Oceania, but their epidemiological role is unknown in the native range of the European rabbit. In this study, scavenging flies were collected between June 2018 and February 2019 in baited traps at one site in southern Portugal, alongside a longitudinal capture-mark-recapture study of a wild European rabbit population, aiming to provide evidence of mechanical transmission of GI.2 by flies. Fly abundance, particularly from Calliphoridae and Muscidae families, peaked in October 2018 and in February 2019. By employing molecular tools, we were able to detect the presence of GI.2 in flies belonging to the families Calliphoridae, Muscidae, Fanniidae and Drosophilidae. The positive samples were detected during an RHD outbreak and absent in samples collected when no evidence of viral circulation in the local rabbit population was found. We were able to sequence a short viral genomic fragment, confirming its identity as RHDV GI.2. The results suggest that scavenging flies may act as mechanical vectors of GI.2 in the native range of the southwestern Iberian subspecies O. cuniculus algirus. Future studies should better assess their potential in the epidemiology of RHD and as a tool for monitoring viral circulation in the field.