Browsing by Author "Ferreira, Mariana"
Now showing 1 - 6 of 6
Results Per Page
Sort Options
- Aplicação de modelo de digestão in vitro para a determinação da bioacessibilidade de patulina em sumos de frutaPublication . Assunção, Ricardo; Martins, Carla; Ferreira, Mariana; Alvito, PaulaO presente estudo pretende determinar a bioacessibilidade da PAT em sumos de fruta, utilizando para o efeito um modelo de digestão in vitro, bem como estudar a influência da composição e natureza do sumo. Considerando que habitualmente os sumos podem ser ingeridos simultaneamente com refeições sólidas, será ainda avaliado o efeito da adição de uma refeição à base de carne.
- Applicability of In Vitro Methods to Study Patulin Bioaccessibility and Its Effects on Intestinal Membrane IntegrityPublication . Assunção, Ricardo; Ferreira, Mariana; Martins, Carla; Diaz, Irene; Padilla, Beatriz; Dupond, Didier; Bragança, Mauro; Alvito, PaulaIn human health risk assessment, ingestion of food is considered a major route of exposure to many contaminants, although the total amount of an ingested contaminant (external dose) does not always reflect the quantity available for the body (internal dose). In this study, two in vitro methods were applied to study bioaccessibility and intestinal membrane integrity of cells exposed to patulin, a mycotoxin with significant public health risk. Seven artificially contaminated fruit juices were assayed in the presence or absence of a standard meal, showing a significant difference for bioaccessibility values between contaminated samples alone (mean 27.65 ± 13.50%) and combinations with a standard meal (mean 7.89 ± 4.03%). Different concentrations of patulin (PAT) and cysteine (CYS) (protector agent) were assayed in Caco-2 cells monolayers. At 95 μM, PAT produced a marked decrease in transepithelial electrical resistance (TEER). This effect was significantly reduced when 400 μM and 4000 μM CYS was added to the cells. Combined use of in vitro digestion models with other techniques using intestinal cell lines, such as in vitro intestinal absorption models that use Caco-2 cells, may offer a more comprehensive model of what is occurring during digestion and absorption processes. The study of beneficial effects of protective agents would also be enhanced.
- Caraterização in vitro dos efeitos tóxicos da patulina na integridade do epitélio intestinal e potenciais efeitos protetores da cisteínaPublication . Assunção, Ricardo; Martins, Carla; Ferreira, Mariana; Alvito, PaulaA mucosa intestinal é a primeira barreira biológica encontrada pelas micotoxinas presentes nos alimentos, sendo a patulina, uma micotoxina produzida por fungos do género Penicillium spp., uma preocupação particular atendendo a que a exposição humana a esta micotoxina pode conduzir a efeitos imunológicos, neurológicos e gastrointestinais. Considerando estes efeitos para a saúde, o presente estudo tem como objetivos a avaliação do efeito tóxico da exposição intestinal a patulina, bem como a determinação do potencial efeito protetor da coadministração de patulina e cisteína na membrana intestinal, utilizando para o efeito células Caco-2. A integridade da membrana intestinal foi determinada pela medição da resistência elétrica transepitelial (TEER). Os resultados evidenciaram um decréscimo acentuado nos valores de TEER após 24 horas de exposição celular a 95 μM de patulina. Para as concentrações mais reduzidas verificou-se uma redução máxima inferior a 25% após 24 horas de exposição. A coadministração de patulina (95 μM) e cisteína (40 μM) revelou um decréscimo nos valores de TEER. O tratamento com cisteína em concentrações superiores ( 400 μM) revelou efeito protetor da membrana intestinal, tendo em conta os valores de TEER. Estes resultados contribuem para uma avaliação do risco mais precisa associada à exposição a contaminantes alimentares.
- Cardiomyopathy and kidney disease in a patient with maternally inherited diabetes and deafness caused by the 3243A>G mutation of mitochondrial DNAPublication . Azevedo, Olga; Vilarinho, Laura; Almeida, Filipa; Ferreira, Francisco; Guardado, Joana; Ferreira, Mariana; Lourenço, António; Medeiros, Rosa; Almeida, JoãoCardiomyopathy is a manifestation of mitochondrial cytopathies, but rarely constitutes the dominant feature, especially in adults. We report the case of a 59-year-old male with a personal and maternal history of diabetes and deafness, who presented with cardiomyopathy and kidney disease. We diagnosed the patient as having a mitochondrial cytopathy resulting from the 3243A>G mutation on the tRNALeu(UUR) gene in the mitochondrial DNA. The family history, broad spectrum of clinical manifestations and fluctuant clinical course provided clues to the diagnosis. We discuss the possible mechanisms underlying the phenotypic variability and fluctuant clinical course of mitochondrial disorders and the potential usefulness of coenzyme Q10 and L-carnitine in 3243A>G mutation patients.
- Identification of novel L2HGDH gene mutations and update of the pathological spectrumPublication . Vilarinho, Laura; Tafulo, Sandra; Sibilio, Michelina; Kok, Fernando; Fontana, Federica; Diogo, Luisa; Venâncio, Margarida; Ferreira, Mariana; Nogueira, Celia; Valongo, Carla; Parenti, Giancarlo; Amorim, António; Azevedo, LuisaL-2-hydroxyglutaric aciduria (L-2-HGA, MIM 236792) is a neurometabolic disorder caused by the toxic accumulation of high concentration of L-2-hydroxyglutaric acid in plasma and cerebrospinal fluid. Distinct mutations on the L2HGDH gene have been associated with the clinical and biochemical phenotype. Here we present three novel mutations (Gln197X, Gly211Val and c.540+1 G4A), which increase the present deleterious collection of L2HGDH gene up to 35 mutations that we have compiled in this study. In addition, we used the haplotypic information based on polymorphic markers to demonstrate the common origin of Gly57Arg harboring chromosomes.
- Mycotoxins and applicability of in vitro methods of digestion and absorption assessment - the patulin case studyPublication . Assunção, Ricardo; Ferreira, Mariana; Martins, Carla; Dupont, Didier; Alvito, PaulaMycotoxins are a wide group of fungal secondary metabolites that exert multiple toxic effects on humans and animals1. Patulin, a mycotoxin with significant public health risk, is a toxic secondary metabolite produced by a wide range of fungal species growing on rotten fruit2. In human health risk assessment, ingestion of food is considered a major route of exposure to many contaminants, although the total amount of an ingested contaminant does not always reflect the amount that is available to the body and exert its toxic effects3. In this study, two in vitro methods were applied to evaluate the bioaccessibility of patulin at different experimental conditions and the intestinal membrane integrity of Caco-2 cells exposed to patulin and cysteine (antioxidant) protective effects. Seven artificially contaminated fruit juices were assayed in the presence or absence of a standard meal showing a significant difference (p=0.001) for bioaccessibility values between contaminated samples alone and combinations with a standard meal4. Different concentrations of patulin and cysteine were assayed in a Caco-2 cells monolayers. At 95 µM, patulin produced a dramatic decrease of transepithelial electrical resistance. This effect was significantly (p=0.016) reduced when 400 µM and 4000 µM of cysteine was added to the cells4. The combination of in vitro digestion models with other techniques using intestinal cell lines offer a more complete picture of what is happening in the digestion and absorption process, as well as the study of beneficial effects of protective agents.