Browsing by Issue Date, starting with "2021-03-26"
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- Avaliação da genotoxicidade de nanomateriais através do ensaio do micronúcleo: Uma comparação interlaboratorial para a sua validação.Publication . Marques, Catarina A.C.; Silva, Maria João; Martins, Francisco Rente de PinaNanomaterials (NMs) have unique physico-chemical characteristics that make them ideal for various applications in numerous areas. With the increase in the use of NMs in some industries and consumer products, among others, human and environmental exposure to these substances has increased more and more, and further studies are needed to understand the potential risks associated with such exposure. Currently, the in vitro micronucleus assay (MN) in cytokinesis-blocked cells is one of the most widely used tests for genotoxic substances assessment and is considered the gold standard when compared to other similar tests. Even though it is an appropriate test, the comparability of the MN assay results is difficult due to inconsistent results reported. Thus, there is a need to develop harmonised protocols and select the most sensitive cell lines, given the particularities of these substances, in order to validate techniques like this one This project, which is part of a larger international study involving interlaboratorial comparisons, aims to optimize the in vitro micronucleus assay to obtain a more sensitive and reliable assay for the evaluation of nanomaterial genotoxicity in mammalian cell lines. The toxicity of nanomaterials was evaluated, namely, cerium dioxide (CeO2), barium sulfate (BaSO4), silica (SiO2), cellulose nanofibrillated (CNF) and cellulose nanocrystalline (CNC), all of them with varied applications in industry and consumer products. Chinese hamster lung fibroblasts (V79 cells) were exposed to different concentrations of each NM during 1 cell cycle (17 hours) to assess cytotoxicity through the MTT assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] and for 4 days for the clonogenic assay. Genotoxicity was assessed by the MN assay after exposure to the same concentration-range of nanomaterials for 17 hours. The results showed a significant decrease in cell viability after exposure to BaSO4 at the highest concentrations (64, 128 and 256 μg/mL) tested. The exposure for 4 days to BaSO4, CNF or CNC led to a decrease in cell proliferation, showing positive cytotoxic effects for these NMs. As for genotoxic effects, assessed by the MN assay, the results revealed a significant increase in the frequency of micronucleated cells after exposure to CNF, as well as to the lowest concentration of BaSO4. CeO2 and SiO2 nanomaterials were not genotoxic. The knowledge generated through this project will contribute to data set on the use of the in vitro micronucleus assay for the genotoxicity assessment of nanomaterials. The results obtained for the several NMs assessed suggest that the protocol used for the MN assay allowed to distinguish differential effects regarding their genotoxicity. Furthermore, the results generated will add to the safety assessment of the NMs under study, thereby contributing to their safe application in industry, consumer products and nanotheranostics. A future interlaboratory comparison will allow to assess the assay reproducibility and adequacy, considering the physical-chemical characteristics of the NMs under test, and the use of standardized protocols will improve results comparability.
- Molecular diagnosis of Maturity Onset Diabetes of the Young: a case for personalized medicinePublication . Poejo, Daniela; Bourbon, MafaldaA diabetes mellitus, é um dos fatores de maior risco para o desenvolvimento de doenças cardiovasculares. Esta patologia é caracterizada por um conjunto de alterações metabólicas causadas pela deficiência na secreção da hormona insulina. Existem vários tipos de diabetes mellitus que diferem tanto nas características clínicas como na sua fisiopatologia. Desde modo, é essencial considerar as formas mais raras de diabetes adequando o tipo de intervenção terapêutica de acordo com as características especificas do tipo de diabetes e do paciente. A diabetes tipo MODY (Maturity Onset Diabetes of the Young) é uma forma monogénica de diabetes descrita pela primeira vez em 1974 por Tattersall. A diabetes tipo MODY é uma doença de origem genética de padrão de hereditariedade autossómico dominante que provoca alterações no normal funcionamento nas células responsáveis pela produção de insula, as células beta do pâncreas. O aparecimento deste tipo de diabetes costuma manifestar-se em crianças e jovens antes dos 25 anos, em indivíduos não-insulino dependentes e sem sinais de insulinorresistência. Apesar de apresentar tanto características clínicas como base genética dispares, individuos com diabetes tipo MODY são frequentemente erradamente diagnosticados com diabetes tipo 1 ou diabetes tipo 2. Além disso, a diabetes tipo MODY apresenta uma elevada heterogeneidade fenotípica e genótipica fazendo com que o teste genético seja extremamente relevante tanto para a otimização do tratamento como para a prevenção de possíveis complicações de saúde associadas a diabetes. Atualmente, sabe-se que alterações genéticas em 1 dos 14 genes associados à MODY podem ser causa patagónica da diabetes. Mutações heterozigóticas nos genes GCK, HNF1A, HNF4A e HNF1B os mais frequentemente encontrados em pacientes com diabetes tipo MODY. Localizado no cromossoma 7 (7p13), o gene GCK codifica a enzima glucocinase (GCK – glucokinase) que desempenha um papel fundamental na primeira fase dos processos metabólicos da glicose. Neste estudo participaram dezanove indivíduos previamente selecionados com características clínicas que permitissem suspeitar de fenótipo de diabetes tipo MODY. Como resultado desre estudo foram detetadas no total vinte variantes com distribuição não uniforme ao longo dos três genes em estudo. O correto diagnóstico e a identificação genotipica de indivíduos com diabetes tipo MODY permite adequar melhores opções terapêuticas. Além disso, a personalização o tratamento de acordo com as características genéticas de cada subtipo parece ser um enorme avanço no melhoramento do controlo glicémico e na prevenção de outras complicação de saúde tendo grande impacto na qualidade de vida dos pacientes e famílias.
- Mycosands: Fungal diversity and abundance in beach sand and recreational waters - Relevance to human healthPublication . Brandão, J.; Gangneux, J.P.; Arikan-Akdagli, S.; Barac, A.; Bostanaru, A.C.; Brito, S.; Bull, M.; Çerikçioğlu, N.; Chapman, B.; Efstratiou, M.A.; Ergin, Ç.; Frenkel, M.; Gitto, A.; Gonçalves, C.I.; Guégan, H.; Gunde-Cimerman, N.; Güran, M.; Irinyi, L.; Jonikaitė, E.; Kataržytė, M.; Klingspor, L.; Mares, M.; Meijer, W.G.; Melchers, W.J.G.; Meletiadis, J.; Meyer, W.; Nastasa, V.; Babič, M. Novak; Ogunc, D.; Ozhak, B.; Prigitano, A.; Ranque, S.; Rusu, R.O.; Sabino, R.; Sampaio, A.; Silva, S.; Stephens, J.H.; Tehupeiory-Kooreman, M.; Tortorano, A.M.; Velegraki, A.; Veríssimo, C.; Wunderlich, G.C.; Segal, E.The goal of most studies published on sand contaminants is to gather and discuss knowledge to avoid faecal contamination of water by run-offs and tide retractions. Other life forms in the sand, however, are seldom studied but always pointed out as relevant. The Mycosands initiative was created to generate data on fungi in beach sands and waters, of both coastal and freshwater inland bathing sites. A team of medical mycologists and water quality specialists explored the sand culturable mycobiota of 91 bathing sites, and water of 67 of these, spanning fromthe Atlantic to the EasternMediterranean coasts, including the Italian lakes and the Adriatic, Baltic, and Black Seas. Sydney (Australia) was also included in the study. Thirteen countries took part in the initiative. The present study considered several fungal parameters (all fungi, several species of the genus Aspergillus and Candida and the genera themselves, plus other yeasts, allergenic fungi, dematiaceous fungi and dermatophytes). The study considered four variables that the team expected would influence the results of the analytical parameters, such as coast or inland location, urban and non-urban sites, period of the year, geographical proximity and type of sediment. The genera most frequently found were Aspergillus spp., Candida spp., Fusarium spp. and Cryptococcus spp. both in sand and in water. A site-blind median was found to be 89 Colony-Forming Units (CFU) of fungi per gram of sand in coastal and inland freshwaters, with variability between 0 and 6400 CFU/g. For freshwater sites, that number was 201.7 CFU/g (0, 6400 CFU/g (p = 0.01)) and for coastal sites was 76.7 CFU/g (0,3497.5 CFU/g). For coastalwaters and allwaters, themedianwas 0 CFU/ml (0, 1592 CFU/ml) and for freshwaters 6.7 (0, 310.0) CFU/ml (p < 0.001). The results advocate that beaches should bemonitored for fungi for safer use and better management.