Browsing by Author "Vilares, A."
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- Alterações fenotípicas e genéticas do metabolismo do ferro numa população portuguesa com doença de Alzheimer: potenciais implicações no conhecimento da fisiopatologia e no diagnóstico desta demênciaPublication . Crespo, A.C.; Silva, B.; Marques, L.; Marcelino, E.; Maruta, C.; Costa, S.; Timóteo, A.; Vilares, A.; Couto, F.S.; Faustino, Paula; Correia, A.P.; Verdelho, A.; Porto, G.; Guerreiro, M.; Herrero, A.; Costa, C.; Mendonça, A.; Martins, M.; Costa, L.
- Deteção molecular de V. cholerae O1 e O139 e caraterização genotípica dos fatores de virulência em estirpes clínicas de V. cholerae isoladas em Angola: resultados preliminaresPublication . Monteiro, L.; Van-Dúnem, F. Reis; Vilares, A.; Sami, J.; Oliveira, E.; Silva, F. Gomes da
- Genetic and biochemical markers in patients with Alzheimer's disease support a concerted systemic iron homeostasis dysregulationPublication . Crespo, A.C.; Silva, B.; Marques, L.; Marcelino, E.; Maruta, C.; Costa, S.; Timóteo, A.; Vilares, A.; Couto, F.S.; Faustino, Paula; Correia, A.P.; Verdelho, A.; Porto, G.; Guerreiro, M.; Herrero, A.; Costa, C.; de Mendonça, A.; Costa, L.; Martins, M.Alzheimer's disease (AD) is the most common form of dementia in the elderly individuals, resulting from a complex interaction between environmental and genetic factors. Impaired brain iron homeostasis has been recognized as an important mechanism underlying the pathogenesis of this disease. Nevertheless, the knowledge gathered so far at the systemic level is clearly insufficient. Herein, we used an integrative approach to study iron metabolism in the periphery, at both genotypic and phenotypic levels, in a sample of 116 patients with AD and 89 healthy control subjects. To assess the potential impact of iron metabolism on the risk of developing AD, genetic analyses were performed along with the evaluation of the iron status profile in peripheral blood by biochemical and gene expression studies. The results obtained showed a significant decrease of serum iron, ferritin, and transferrin concentrations in patients compared with the control subjects. Also, a significant decrease of ferroportin (SLC40A1) and both transferrin receptors TFRC and TFR2 transcripts was found in peripheral blood mononuclear cells from patients. At the genetic level, significant associations with AD were found for single nucleotide polymorphisms in TF, TFR2, ACO1, and SLC40A1 genes. Apolipoprotein E gene, a well-known risk factor for AD, was also found significantly associated with the disease in this study. Taken together, we hypothesize that the alterations on systemic iron status observed in patients could reflect an iron homeostasis dysregulation, particularly in cellular iron efflux. The intracellular iron accumulation would lead to a rise in oxidative damage, contributing to AD pathophysiology.
- Isolation and molecular characterization of Toxoplasma gondii isolated from pigeons and stray cats in Lisbon, PortugalPublication . Vilares, A.; Gargaté, M.J.; Ferreira, I.; Martins, S.; Júlio, C.; Waap, H.; Angelo, H.; Gomes, João PauloCats and pigeons are important factors in the epidemiology of Toxoplasma gondii as felidsare the only definitive hosts that can excrete environmentally resistant oocysts, andpigeons share the same places of cats and humans constituting a good model and indicatorof the ground field contamination. We aimed to study the virulence and genotypes ofT. gondii isolated from pigeons and stray cats in Lisbon, Portugal. Fresh samples of brainfrom 41 pigeons and 164 cats revealing antibodies to T. gondii were inoculated in mice.Three isolates (one isolated from a cat and two isolated from pigeons) were virulent in themouse model. Sag2-based genotyping of T. gondii was achieved in 70.7% (29/41) of samplesisolated from pigeons (26 samples were type II, two were type III, and one strain was type I).From the cat brain samples, 50% (82/164) yielded Sag2 positive results, where 72 belongedto genotype II and 10 were no type III (it was not possible to discriminate between typeI and II). Further genotyping was obtained by multiplex PCR of 5 microsatellites (TUB2,TgM-A, W35, B17, B18), allowing the identification of two recombinant strains that hadbeen previously identified as type II by Sag2 amplification (one isolated from cat brain andthe other from pigeon brain). This is the first evidence of recombinant strains circulatingin Portugal and the first report of T. gondii genotyping from cats in this country. This studyalso highlights the importance of environmental contamination in the synanthropic cycleconstituting a potential source of human infection.
- Seroepidemiology of Toxoplasma gondii infection in women from the North of Portugal in their childbearing yearsPublication . Lopes, A.P.; Dubey, J.P.; Moutinho, O.; Gargate, M.J.; Vilares, A.; Rodrigues, M.; Cardoso, L.Seroprevalence of Toxoplasma gondii infection and associated risk factors were investigated in 401 women of childbearing age from the North of Portugal. Of the 98 (24·4%) seropositive women, 92 (93·9%) only had immunoglobulin (Ig)G, two (2·0%) only had IgM, and four (4·1%) others had both IgG and IgM. Risk factors for T. gondii infection in women were: engaging in soil-related activities without gloves [odds ratio (OR) 8·4], consumption of unwashed raw vegetables or fruit (OR 7·6), and consumption of smoked or cured (non-cooked) processed pork products (OR 2·5). Most women of childbearing age from the North Portugal are susceptible to primary infection with T. gondii and, therefore, the risk of congenital toxoplasmosis remains high.