Percorrer por autor "Oliveira, C."
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- Assessment of multiple mycotoxins in breakfast cereals available in the Portuguese marketPublication . Martins, Carla; Assunção, Ricardo; Cunha, S.; Fernandes, José; Jagger, A.; Petta, T.; Oliveira, C.; Alvito, PaulaMycotoxins are secondary metabolites of fungi that cause toxic and carcinogenic effects. Human exposure to multiple mycotoxins constitutes an increasing health concern due to potential mycotoxins combined effects. The presence of mycotoxins mixtures in foodstuffs as cereals has been reported over the last years, but few studies are available concerning its occurrence in cereals primarily marketed for children, a particular vulnerable population group. The present study aims to assess the co-occurrence of twenty-one mycotoxins and metabolites present in breakfast cereals primarily marketed for children in Portugal. Results showed that 96% of the analysed breakfast cereal samples were contaminated with several mycotoxins. Twenty-two combinations were identified including two to seven different mycotoxins. Conclusions pointed out an urgent need to review legislative limits in food matrices consumed by children and to perform a more accurate risk assessment of children’s exposure to mycotoxins mixtures in food.
- Assessment of multiple mycotoxins in maize flour samples from Portugal under SafeGrains projectPublication . Duarte, S.; Magro, A.; Oliveira, C.; Rosim, R.; Alvito, Paula; Carvalho, M.O.One of the most relevant problems in stored grains is the contamination by insects and mycotoxin-producing fungi. Tribolium castaneum is one of the most common insect pests of stored products. Its presence makes cereals more susceptible to the spread of the fungi Aspergillus flavus, which may produce mycotoxins. The aim of this work was to evaluate the mycotoxin profile of maize flour infested by T. castaneum adults, alone or in combination with mycotoxigenic A. flavus strain (MUM-UMinho). Maize collected directly from fields was stored at 4 ºC and then ground and sieved to obtain maize fl our. Multiple mycotoxin profile of maize flour was determined in three different assays: i) controls (n=8), ii) inoculated with T. castaneum adults (insect assay, n = 24), iii) inoculated with A. flavus conidia (fungus assay, n = 8) and iv) inoculated with both organisms (mixed assay, n = 24). Samples were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) according to Franco et al. (2019) for determination of aflatoxins (AFs) B1, B2, G1 and G2, deoxynivalenol (DON), zearalenone(ZEN) and fumonisins (FBs) B1 and B2. The limits of detection (LOD) and quantification (LOQ) of the analytical method were 6.1 and 18.0 μg/ kg for DON, respectively. For AFs, ZEN and FBs, LOD and LOQ varied between 0.2 – 0.9 and 0.6 – 2.5 μg/kg, respectively. DON, ZEA, FB1 and FB2 were detected in control assays at mean levels ranging from 33-50, 2-6, 112-144 and 49-75 μg/kg, respectively. AFs were not detected in controls. Insect, fungi and mixed assays presented the same mycotoxin profile (with contents in the same order of magnitude), except for AFB1, which was detected only in mixed assays. Although the levels of mycotoxins are below the legislated ones (Commission Regulation (EU) 2023/915), they point out to the presence of multiple mycotoxins in raw maize flour and to a potential impact between insects and mycotoxigenic strains in which concerns AFB1. Data presented here agree with previous assays from this team describing significantly higher concentration in the maize flour inoculated with both organisms (Duarte et al, 2021).
- Assessment of mycotoxin exposure and risk characterization using occurrence data in foods and urinary biomarkers in BrazilPublication . Franco, Larissa; Petta, T.; E.Rottinghaus, George; Bordin, Keliani; A.Gomes, Gilmar; Alvito, P.; Assunção, R.; Oliveira, C.This study aimed to assess the exposure of residents (N=86) from rural areas to multiple mycotoxins and characterize the associated risk in two sampling periods (SP) (April–May and December/2016). Mycotoxins in food and urine samples were determined by liquid chromatography coupled to tandem mass spectrometry. Mean probable daily intake (PDI) values based on occurrence data in foods in both SP varied from 0.007 to 0.013, 0.069 to 1.002, 0.119 to 0.321 and 0.013–0.156 μg kg−1 body weight (bw) day−1 for aflatoxins (AFs), deoxynivalenol (DON), fumonisins (FBs) and zearalenone (ZEN), respectively. Mean PDI values based on urinary biomarkers were 0.001, 84.914, 0.031, 0.377 and 0.002 μg kg−1 bw day−1 for AFB1, DON, ochratoxin A (OTA), FB1 and ZEN, respectively. Hazard quotient (HQ) calculated using food data revealed a potential health concern for ZEN in 2nd SP. HQ > 1 based on urinary biomarkers were observed for DON in the two SP. Although OTA was not detected in any food sample, the HQ based on urinary OTA levels was>1 in the 1st SP. Margin of exposure values for AF from food and urine data in the 1st SP were below 10,000, indicating potential health risks.
- Brief report: High frequency of biochemical markers for mitochondrial dysfunction in autism: no association with the mitochondrial aspartate/glutamate carrier SLC25A12 genePublication . Correia, C.; Coutinho, A.M.; Diogo, L.; Grazina, M.; Marques, C.; Miguel, T.; Ataíde, A.; Almeida, J.; Borges, L.; Oliveira, C.; Oliveira, G.; Vicente, A.M.In the present study we confirm the previously reported high frequency of biochemical markers of mitochondrial dysfunction, namely hyperlactacidemia and increased lactate/pyruvate ratio, in a significant fraction of 210 autistic patients. We further examine the involvement of the mitochondrial aspartate/glutamate carrier gene (SLC25A12) in mitochondrial dysfunction associated with autism. We found no evidence of association of the SLC25A12 gene with lactate and lactate/pyruvate distributions or with autism in 241 nuclear families with one affected individual. We conclude that while mitochondrial dysfunction may be one of the most common medical conditions associated with autism, variation at the SLC25A12 gene does not explain the high frequency of mitochondrial dysfunction markers and is not associated with autism in this sample of autistic patients.
- Genetic variants of CYP2C9 and IL-6 on female infertilityPublication . Cardoso, R.; Gonçalves, A.; da Silva, J.M.; Oliveira, C.; Xavier, P.; Alves, H.; Barros, A.; Botelho, M.C.AIM: To study the polymorphic variants in CYP2C9*2*3 and the C-174G promoter polymorphism of the IL-6 gene on Infertile Women.BACKGROUND: - Infertility affects 15–20% of couples worldwide. Within the past decades, there has been a steady rise in the treatment of female infertility with several drugs; - The cytochrome P450 (CYP) genes are oxygenases involved in estrogen biosynthesis and metabolism, generation of DNA damaging procarcinogens, and response to anti-estrogen therapies used in female infertility treatments: - Interleukin-6 (IL-6) is a pleiotropic proinflammatory cytokine, highly expressed in the female urogenital tract and reproductive organs. It has been implicated in estrogen metabolism imbalance.
- Ocorrência de micotoxinas em alimentos comercializados em PortugalPublication . Martins, Carla; Assunção, Ricardo; Pires, M.J.; Cunha, S.; Petta, T.; Jagger, A.; Oliveira, C.; Alvito, PaulaAs micotoxinas são metabolitos secundários produzidos por fungos e que causam efeitos tóxicos e cancerígenos no Homem e em animais. As micotoxinas podem contaminar vários géneros alimentícios, incluindo cereais e produtos derivados, fórmulas infantis, leite, fruta, entre outros; constituem assim, não só um problema de segurança alimentar, mas também um problema económico. O objetivo deste estudo foi determinar a incidência e os teores de 21 micotoxinas e metabolitos (AFB1, AFB2, AFG1, AFG2, AFM1, OTA, FB1, FB2, NIV, ZEA, NEO, DAS, FUS-X, DON, 15-ADON, 3-ADON, HT-2, T-2, VER, T-2 TETROL, T-2 TRIOL) em alimentos disponíveis no mercado português, e comparar os resultados com os limites máximos estabelecidos pela União Europeia. Para este estudo foram analisadas por HPLC-FLD, LC-MS/MS e GC-MS, amostras de cereais de pequeno-almoço (n=26), farinhas infantis (n=20), fórmulas infantis (n=10), bolachas (n=6) e leites UHT (n=21), num total de 83 amostras. Os resultados obtidos mostraram que 96% dos cereais de pequeno-almoço, 50% das farinhas infantis, 50% das bolachas, 40% das fórmulas infantis, e 19% dos leites UHT, estavam contaminados com micotoxinas (valores acima do limite de detecção), embora todas as amostras apresentassem níveis abaixo dos limites máximos estabelecidos no Regulamento 1881/2006 e na Recomendação 165/2013 da Comissão Europeia. A co-ocorrência de micotoxinas diferentes na mesma amostra foi também observada com elevada incidência nas amostras analisadas (92% em cereais pequeno-almoço, 70% em farinhas infantis, 50% em bolachas, 40% em fórmulas infantis, 19% em leites UHT). Estes resultados contribuem para o conhecimento sobre os teores de micotoxinas nos alimentos comercializados em Portugal e consumidos por crianças jovens, salientando assim a necessidade de uma revisão da legislação com vista à diminuição dos limites legais para micotoxinas nos cereais pequeno-almoço, à inclusão de novas combinações matriz alimentar-micotoxina, e ainda a consideração das misturas de micotoxinas nos alimentos. A última questão é particularmente importante considerando os possíveis efeitos sinérgicos que podem ocorrer entre as micotoxinas e seu potencial impacto na saúde humana e, principalmente, na saúde das crianças.
- Urinary Estrogen Metabolites and Self-Reported Infertility in Women Infected with Schistosoma haematobiumPublication . Santos, J.; Gouveia, M.J.; Vale, N.; Delgado, M. de L.; Gonçalves, A.; da Silva, J.M.; Oliveira, C.; Xavier, P.; Gomes, P.; Santos, L.L.; Lopes, C.; Barros, A.; Rinaldi, G.; Brindley, P.J.; da Costa, J.M.; Sousa, M.; Botelho, M.C.Schistosomiasis is a neglected tropical disease, endemic in 76 countries, that afflicts more than 240 million people. The impact of schistosomiasis on infertility may be underestimated according to recent literature. Extracts of Schistosoma haematobium include estrogen-like metabolites termed catechol-estrogens that down regulate estrogen receptors alpha and beta in estrogen responsive cells. In addition, schistosome derived catechol-estrogens induce genotoxicity that result in estrogen-DNA adducts. These catechol estrogens and the catechol-estrogen-DNA adducts can be isolated from sera of people infected with S. haematobium. The aim of this study was to study infertility in females infected with S. haematobium and its association with the presence of schistosome-derived catechol-estrogens.