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Browsing Departamento de Química by Field of Science and Technology (FOS) "Engenharia e Tecnologia::Bioquímica"
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- Adverse vascular effects of phthalates: Possible contribution to hypertension in pregnancyPublication . Mariana, Melissa Rodrigues; Oliveira, Maria Elisa Cairrão Rodrigues; Soares, Amadeu Mortágua Velho da Maia; Sousa, Miguel Castelo Branco Craveiro dePhthalates are chemical compounds used as plasticizers to increase flexibility and elasticity of rigid polymers and as non-plasticizers as solvents and additives in cosmetics and personal care products. These compounds have low water solubility and since they are not covalently bound to the polymer they are easily released into the environment and absorbed by the human body. Afterwards, phthalates are rapidly metabolized into their respective monoesters being already detected in different biological samples, including blood, urine, saliva, amniotic fluid, umbilical cord blood and breast milk. In addition, phthalates can disrupt the endocrine system by binding to molecular targets and interfering with hormonal homeostasis, thus being classified as endocrine-disrupting compounds (EDCs). Due to these properties and their adverse effects, phthalates were classified as priority environmental pollutants by the United States Environmental Protection Agency (US EPA). Alongside this increase in exposure to phthalates, the incidence of cardiovascular diseases (CVD) has also increased over the years, with the occurrence of hypertensive disorders in pregnancy (HDP) being one of the main causes of maternal and foetal morbidity and mortality. There are several risk factors that influence the development of HDP, including exposure to EDCs, but the mechanisms involved are not yet known. Several studies have also suggested an association with phthalates, in rats they seem to promote changes in the vascular function, to affect the expression of proteins involved in cardiac function, to contribute to increased blood pressure, changes in lipid metabolism, and atherosclerosis. Thus, the aim of this thesis was to investigate how phthalates’ exposure affects the cardiovascular health, focusing on HDP. For that, studies were carried out on rat aorta and the human umbilical artery to evaluate the effects of di(2-ethylhexyl) phthalate (DEHP) and diethyl phthalate (DEP) in the vascular function. In the first study, rat aorta devoid of endothelium was contracted with noradrenaline and potassium chloride (KCl) and then subjected to different concentrations of DEHP (0.001-100 μM) to assess the vascular reactivity. Besides, since Ca2+ levels are the main determinant of contraction and relaxation, DEHP effects on Ca2+ currents were also analysed using the A7r5 cells. The data obtained showed that DEHP caused a concentration-dependent vasorelaxation after contraction with KCl, and, at the highest concentrations, it inhibited both the basal and the BAY K8644-stimulated calcium currents. These results suggest that DEHP induces vasorelaxation of the rat aorta by inhibiting the L-type Ca2+ channels (LTCC). Then, the genomic and non-genomic effects of DEP on the rat aorta were analysed. Using the organ bath technique, DEP (0.001-1000 μM) was analysed after contraction of the arteries with noradrenaline and KCl. Similarly, to understand the possible mechanisms involved, the effects of DEP were analysed on the relaxing effect of nifedipine (NIF - specific calcium channel blocker) and sodium nitroprusside (SNP - soluble guanylate cyclase activator). Besides, through electrophysiology studies the non-genomic (occurring within a few minutes) and genomic (occurring after 24h of exposure) effects of DEP on the Ca2+ currents of the A7r5 cells were investigated. These showed that both the rapid and 24h effects of DEP exposure led to a decrease in LTCC currents, being in agreement with the vasorelaxation obtained through the organ bath experiments. For the first time, the vascular electrophysiological properties of an EDC were analysed after long-term exposure, concluding that DEP promotes an inhibition of the calcium current in the rat aorta, which may be responsible for electrical disturbances such as arrhythmias. To evaluate the effect of phthalates on maternal health, the last experimental work of this thesis analysed the contribution of DEP (0.001-1000 μM) in the development of gestational hypertension. Therefore, human umbilical arteries (HUA) were collected from normotensive and hypertensive pregnant women. To assess the non-genomic vascular effects, the HUA were pre-contracted with serotonin, histamine and KCl and then subjected to DEP, resulting in a vasorelaxation by interfering with Ca2+ channels and serotonin and histamine receptors. On the other hand, to assess the genomic effects, the arteries were incubated with DEP for 24h, and then the effects of NIF and SNP were analysed. The results showed that DEP seemed to act through the NO/sGC/cGMP/PKG signalling pathway, and to interfere with LTCC. In addition, primary culture of HUA smooth muscle cells was also performed for cell viability essays, showing that DEP has no toxic effect on these cells. Overall, this experimental work showed that DEP affects the HUA vascular resistance through disturbances in hormone and calcium homeostasis, suggesting that the development of hypertension in pregnancy may be a consequence of exposure to phthalates. In general, the results obtained show that phthalates modify the vascular homeostasis in both animals and humans, promoting vasorelaxation mainly through the inhibition of Ca2+ channels. This is the first time that an experimental study has been able to establish the link between exposure to DEP and gestational hypertension. We are beginning to unravel the mechanistic pathways involved in the vascular effects of phthalates that explain the pathological functional alterations of hypertension in pregnancy. However, more experimental studies are needed to understand how different classes and mixtures of phthalates affect the cardiovascular health during pregnancy and in future generations.
- Agentes anticancerígenos derivados da funcionalização de corantes cianínicos com ácidos barbitúricosPublication . Varges, Alexandra Miguel Morgado; Serrano, João Paulo Lourenço; Boto, Renato Emanuel Félix; Silvestre, Samuel MartinsO cancro tem sido, ao longo dos anos, motivo de grande preocupação, uma vez que o seu nível de incidência e mortalidade, tendem a aumentar com o decorrer dos tempos. Diversas têm sidos as terapêuticas desenvolvidas e utilizadas no combate desta doença e, cada vez mais, as cianinas têm tido impacto neste mesmo contexto, como agentes antiproliferativos, nomeadamente as monometinocianinas. Associados a esta premissa estão também os barbituratos, os quais têm um largo espetro terapêutico, incluindo ação anticancerígena. Alguns estudos demonstraram resultados motivadores neste âmbito, decorrentes da junção destes dois tipos de compostos. Tendo estes aspetos em vista, no presente trabalho, foram sintetizadas 11 cianinas funcionalizadas com barbitúricos, as quais, bem como os seus precursores sintéticos, foram posteriormente avaliados biologicamente em duas linhas celulares cancerígenas (MCF-7 e Caco-2) e uma linha não cancerígena (NHDF). Destes ensaios, concluiu-se que os precursores avaliados biologicamente não têm um efeito citotóxico relevante nas linhas celulares cancerígenas, ao passo que reduzem marcadamente a proliferação das células não cancerígenas. Também foram avaliados quanto ao seu efeito inibitório da enzima xantina oxidase, não revelando efeito significativo. Relativamente às cianinas, estas foram avaliadas biologicamente nas concentrações de 1 e 10 µM nas mesmas linhas celulares, e foram realizados estudos de concentração-resposta para as mais potentes. Verificou-se que as monometinocianinas assimétricas, de um modo geral, são muito mais citotóxicas do que as trimetinocianinas assimétricas e que as cianinas simétricas são muito menos citotóxicas do que as assimétricas. Observou-se também que, quanto maior for o grupo substituinte dos nitrogénios dos barbitúricos, menor a sua citotoxicidade. Globalmente, a cianina de maior destaque foi a monometinocianina assimétrica 20a, a qual apresentou os melhores resultados tendo em conta a potência e a seletividade entre células tumorais/nãotumorais. Futuramente, será importante a realização de ensaios complementares, como, por exemplo, a avaliação do efeito destes compostos no ciclo celular e na indução de apoptose, bem como estudos de microscopia de fluorescência para determinar os locais em que se localizam preferencialmente nas células.
- Análise da influência dos genótipos do gene GSTT1 no desenvolvimento de lesão por HPVPublication . Sousa, Cíntia Maia de; Patricio, Ana Cristina Monteiro Ramalhinho Tavares; Granadeiro, Luiza Augusta Tereza Gil Breitenfeld ; Almeida, Micaela Carina PereiraO cancro do colo do útero é um dos cancros mais comuns na população feminina. Esta neoplasia pode desenvolver-se a partir de lesões intraepiteliais que podem ter origem em infeções persistentes por HPV de alto risco. Estas infeções se não forem detetadas e tratadas precocemente, podem evoluir para cancro do colo do útero. O vírus do papiloma humano é um vírus de ADN que pertence à família Papillomaviridae, sendo um dos vírus sexualmente mais transmissíveis. O HPV tem mais de 200 subtipos podendo ser dividido em grupos de alto e de baixo risco, estando os grupos de alto risco mais relacionados com infeções persistentes e o desenvolvimento de patologias. Neste trabalho pretendeu-se estudar a presença e a influência do genótipo “null” do GSTT1 no desenvolvimento de lesão por HPV. A GSTT1 pertence a uma família de enzimas de fase II que atuam no metabolismo xenobiótico conjugando metabolitos com a glutationa tornando-os mais hidrossolúveis e consequentemente reduzindo o efeito citotóxico. Foram utilizadas amostras de tecido da cérvix uterina de 45 mulheres, das quais se extraiu ADN genómico para posteriormente se identificar a estirpe de HPV através de PCR. A determinação do genótipo do GSTT1 foi realizada por Real-Time PCR. Das 45 amostras utilizadas, em 22 foi possível identificar o genótipo “null” do GSTT1. Na população em estudo, parece não existir relação entre o polimorfismo “null” do gene GSTT1 e o desenvolvimento de lesão por HPV. Atualmente, na literatura existem ainda poucos estudos relacionados a este tema. Investigações futuras poderão vir a clarificar o papel do genótipo “null” do GSTT1 no desenvolvimento de lesão por HPV.
- Análise Microbiana aos Ralos de Lavatórios do Hospital Pêro da Covilhã e Relatório de Estágio em Análises ClínicasPublication . Neto, Miguel Amaral; Monteiro, Andreia Sofia dos Reis; Silvestre, Samuel MartinsUm laboratório clínico é uma instalação que tem como principais objetivos a recolha e tratamento de amostras biológicas dos utentes, de modo que possam ser feitas determinações analíticas fiáveis e válidas em tempo útil, de maneira a poder ser estabelecido um diagnóstico clínico para que, posteriormente, caso seja necessário, se possa indicar uma terapia adequada ao diagnóstico do utente. O Laboratório de Patologia Clínica (LPC) da Unidade Local de Saúde da Cova da Beira é constituído por várias secções de diagnóstico, pelo que o presente relatório retrata a passagem pelas secções de Imunoquímica, Microbiologia e Hematologia, tendo sido desenvolvido um projeto de investigação na secção de Microbiologia. Nas últimas décadas, o aumento do número de infeções por microrganismos multirresistentes levou a Organização Mundial de Saúde (OMS) a classificar a resistência aos antibióticos como a principal ameaça do século XXI contra a saúde pública. Estas bactérias multirresistentes são responsáveis por provocar infeções associadas aos cuidados de saúde (IACS), estando associadas a prognósticos desfavoráveis. Estas bactérias possuem a capacidade de formar biofilmes, sendo a canalização hospitalar um dos locais onde estes se podem formar. Este facto levou a que os lavatórios fossem identificados como potenciais fontes de transmissão de microrganismos multirresistentes causadores de infeções aos doentes hospitalizados localizados a menos de 1 metro de distância. Neste sentido, o objetivo deste projeto de investigação foi avaliar, durante um período de 4 semanas, a presença de três microrganismos multirresistentes na canalização de 24 lavatórios, distribuídos por três serviços do Hospital Pêro da Covilhã, tendo sido testada em simultâneo a eficácia de dois desinfetantes na eliminação dos biofilmes. Os microrganismos estudados foram o Staphylococcus aureus meticilina resistente (MRSA), a Klebsiella pneumoniae produtora de carbapenemases (KPC) e o Acinetobacter baumannii, enquanto os desinfetantes comparados foram o Klorkleen Plus (Imporquímica®) e o Granulado Desinfetante Efervescente (Agadesinfect®). A recolha de dados teve início no dia 22 de janeiro de 2024 tendo terminado a 15 de abril, durante esse período foram recolhidas 190 amostras a partir das quais foram gerados 570 resultados. Dos resultados obtidos 48 (8,4 %) foram positivos para os microrganismos em estudo, sendo 25 (4,4 %) positivos para MRSA e 23 (4,0 %) positivos para KPC. Relativamente ao Acinetobacter baumannii, não foi registado qualquer caso positivo em nenhum dos lavatórios estudados. Com base nos dados do crescimento destes microrganismos ao longo das semanas de estudo, foi possível avaliar qual o desinfetante mais eficaz na eliminação do biofilme, sendo que dos dois desinfetantes o Granulado Desinfetante Efervescente foi aquele que apresentou melhor eficácia na eliminação dos biofilmes. Com base no número de IACS em 2023 no Hospital Pêro da Covilhã e tendo em conta os dados da eficácia do referido Granulado na eliminação do biofilme, justifica-se a necessidade de criação de um protocolo de desinfeção periódica dos lavatórios com este desinfetante com o objetivo de controlar e diminuir o número de IACS provocadas por estes microrganismos multirresistentes nesta unidade hospitalar.
- Analysis of the regulation of drug uptake and detoxification systems in the blood cerebrospinal fluid barrier: the role of sex hormones and circadian rhythmPublication . Mineiro, Rafael Morais; Paixão, Telma Alexandra Quintela; Gonçalves, Isabel Maria Theriaga Mendes VarandaThe choroid plexus (CP), localized in the brain ventricles, forms the bloodcerebrospinal fluid barrier, which, by the presence of thigh junctions, detoxification enzymes, and membrane transporters limit the traffic of molecules into the brain. Sex hormones influence several CP functions, including its activity as a circadian oscillator. This study aims to evaluate the impact of sex hormones and circadian rhythms in the function of CPs´ membrane transporters. First, we compared the diary expression of Abca1, Abcc1, Abcc4, Abcg4, and Oat3 transporters in the CP of male and female rats. We observed a circadian expression of Abcc1 and Oat3 in female rats and Abcg4 in male rats, suggesting that sex hormones influence the rhythmicity in the expression of these transporters in CP. Next, we also compared the 24 hours transcription profile of Abca1, Abcc1, Abcc4, Abcg4, and Oat3 in the CP of sham-operated and ovariectomized female rats. We found that Oat3 circadian expression is dependent on ovarian hormones. Using an in vitro model of the human blood-cerebrospinal fluid barrier, we also found that methotrexate (MTX), a very unspecific substrate in terms of transport, is transported in a circadian way across this barrier. Moreover, we demonstrate that Abcc4 is also expressed in a circadian way in the human CP epithelial papilloma cells and is partially responsible for the MTX circadian transport across the basal membrane of choroid plexus epithelial cells.
- Androgen actions regulating TRIB1/3 in prostate cancer: effects on cell proliferation, survival, and metabolismPublication . Shologu, Ziyanda; Socorro, Sílvia Cristina da Cruz Marques; Kiss-Toth, EndreProstate cancer (PCa) is an androgen-sensitive neoplasia with cell survival and proliferation being dependent on androgenic regulation. At this stage, PCa cases can be treated with androgen deprivation therapy (ADT), which aims to decrease the circulating levels of androgens or block their actions. However, genetic alterations including the fusion of genes, amplification of oncogenes, gene mutations and deletions concur promoting the advance of the disease to more aggressive forms. Following this, phenotypic/behaviour changes such as loss of androgen sensitivity occur, allowing the cancer cells grow even if circulating androgens are low. It is the so-called castrate resistant prostate cancer (CRPC). A well-established observation ‘in several cancer cell types is the Warburg effect’, the metabolic reprogramming that enables cancer cells to survive, proliferate and metastasize, using high amounts of glucose as energy substrate, both in aerobic and anaerobic conditions. Tumour cells using glycolysis to maintain energy needs, subsequently produce high amounts of lactate that is exported to the extracellular medium. In the case of PCa, the metabolic reprogramming towards the more glycolytic phenotype accompanies the progression of disease to the CRPC. It was demonstrated that androgens are important regulators of PCa cells metabolism, enhancing glycolysis as well as lipid handling. The pseudokinase family Tribbles (TRIBs), which includes TRIB1, TRIB2 and TRIB3, has been described to have a role in controlling differentiation, transcription, proliferation, and metabolism. These pseudokinase proteins are characterized by functioning as scaffold-like or adaptor molecules in many signalling pathway networks including mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K-AKTf) modules. Consistent with the described actions and the control of intracellular signalling, TRIBs have being involved in disease development, as well as are implicated in several cancers. Evidence indicates the oncogenic role of TRIB1 and TRIB3 and their highly expressed state in tumour initiation and progression, especially in melanoma, lung, liver, and acute leukemia, but also in PCa. Yet, the mechanisms that control TRIBs expression in PCa are still poorly understood. Moreover, the involvement of TRIB1 and TRIB3 in lipids homeostasis has been demonstrated. The main goal of this thesis was to investigate the role of androgens in regulating TRIB1 and TRIB3 expression in PCa and to shed light on the influence of TRIBs on prostate cell fate. The androgenic modulation of TRIBs in PCa cells was determined using 10 nM 5α-dihydrotestosterone (DHT), in the presence or absence of the anti- androgen bicalutamide (10 μM). DHT treatment decreased TRIB1 and TRIB3 expression at a protein and mRNA level in the androgen sensitive LNCaP and 22Rv1 cells with no changes observed in the non-neoplastic PNT1A cells. Bicalutamide (10 μM) blocked the effect of DHT in down-regulating TRIB1 expression in LNCaP and 22Rv1 cells, which suggests the involvement of the androgen receptor (AR). These findings were validated by the expression analysis of the standard androgen- responsive gene prostate-specific antigen (PSA), confirming its increased expression in DHT treated cells and blocking of effects by bicalutamide. To further study the impact of the AR in TRIB1 regulation, we performed a knockdown (KD) of the AR in LNCaP and 22Rv1 cells and measured TRIB1 expression. AR KD resulted in a significant TRIB1 increase in 22Rv1 cells at an mRNA level. These outcomes are in line with those obtained in-vivo, as castrated mice displayed increased TRIB1 mRNA expression levels compared to control, which highlights the androgens’ regulatory effects of TRIBs in PCa. Moreover, using ChiP-seq analysis in human primary tumours vs normal solid tissues it was shown that AR directly binds to the TRIB1 and TRIB3 gene locus. LNCaP cells treated with the synthetic androgen r1881 also showed a similar pattern of TRIBs downregulation. Together these findings provide useful insight into AR actions in regulating TRIB1 expression in PCa. Concerning the physiological effects on PCa cell fate, enhanced cell viability, proliferation and migration were observed in androgen treated cells, whereas no alterations were seen on caspase-3 activity. TRIBs associated signalling pathways targets such as pERK and pAKT, prominently known to have roles in survival, apoptosis, and differentiation in response to a range of stimuli including steroid hormones were also measured after 10 nM DHT treatment and downregulation of their expression was observed. TRIB1 has been shown to be overexpressed in PCa and associated with the progression of disease. However, it is not clear if is the TRIB1 increased expression levels that promote the malignant transformation of prostate cells. Therefore, the influence of TRIB1 expression levels in non-neoplastic (PNT1A) and neoplastic (PC3) prostate cells fate was investigated. TRIB1 overexpression (OE) on PNT1As increased cell proliferation and migration, with no changes on caspase-3 activity and cell viability. The effect of TRIB1 OE on lipid metabolism was also measured and a significant increase of lipid droplets was observed in PNT1A cell OE TRIB1. This was accompanied by the increased expression of fatty acid synthase (FASN), a key target protein in lipid metabolism in neoplastic conditions. Overall, TRIB1 OE changed the features of non-neoplastic PNT1A cells to a cancer-like phenotype. Interestingly, no changes were observed on the viability, proliferation and metabolism of TRÎB1 knockdown PC3 cells. These results implicate TRIB1 in the regulation of metabolism, as well as suggest its role as a ‘driving force’ for tumour initiation and progression of disease in the early stages of PCa development. In summary, this dissertation demonstrated the androgen actions in the regulation of TRIBs in PCa cells. Revealing the link between TRIBs, androgens and AR in PCa development and progression. Collectively, further research on these interaction warrants TRIBs as a basis for the development of new therapeutic approaches for PCa.
- Aplicação de dried saliva spots na determinação de marcadores de consumo de tabacoPublication . Marques, Hernani Fortunato; Rosado, Tiago Alexandre Pires; Alba, Maria Eugénia Gallardo; Passarinha, Luís António PaulinoExposure to tobacco smoke is one of the most common causes of premature death worldwide and is the cause of 8 million deaths annually. For this purpose, it was developed, optimized, and validated a procedure for the detection of nicotine, cotinine and trans-3-hydroxycotinine (biomarkers of tobacco exposure) in oral fluid using the dried saliva spots sampling approach and gas chromatography coupled to tandem mass spectrometry, thus allowing the distinction between active and passive smokers. For optimization, 4 parameters were evaluated, namely extraction solvent, extraction solvent volume, extraction time and spots drying time. During method validation, the parameters selectivity, linearity, precision and accuracy, recovery, stability, and dilution factor were assessed. Linearity was obtained for all target analytes in the concentration range of 10-200 ng/mL allowing the quantification of compounds up to 1000 ng/mL considering the dilution factor. The method recoveries ranged from 29.2% to 43.30% for nicotine, 66.60% to 89.10% for cotinine and 80.30% to 92.80% for trans-3-hydroxycotinine, while achieving intra-day, inter-day and intermediate precision and accuracy values never greater than 10.37% and ± 6.50% respectively for all compounds. The herein described analytical method is the first that allows the determination of tobacco biomarkers in oral fluid using dried saliva spots, being considered a sensitive, simple, and low-cost alternative to conventional methods.
- Assess of catechol-O-methyltransferase soluble isoform by multiple reaction monitoring mass spectrometryPublication . Diogo, Joana Margarida Santos; Passarinha, Luís António PaulinoCOMT is an enzyme that catalyses the transfer of the methyl group from S-adenosyl-L-methionine to the hydroxyl group of a large variety of catechols, including catechol-estrogens and the neurotransmitters dopamine and norepinephrine. The protein is expressed in both a soluble form (SCOMT) and a membrane-bound form with additional 50 residues at the N-terminal (MBCOMT). In most human tissues, the majority of COMT is present in soluble form and only a small fraction as MBCOMT. The human COMT gene has a common single-nucleotide polymorphism that results in substitution of methionine for valine at residue 108 of soluble protein and residue 158 of the membrane bound enzyme. The two alleles have been associated with several neurologic diseases, such as schizophrenia, anorexia nervosa and obsessive-compulsive disorder. Thus, due to the COMT's role in several mental disorders, accurate and selective measurements are essential requirements for improvement the COMT clinical investigation. Thus, in this work a specific and low-cost methodology is developed in order to measure COMT protein in Pichia pastoris lysates by liquid chromatography-multiple reaction monitoring (MRM) mass spectrometry. The method was validated according to international guidelines evaluating selectivity, linearity, precision and accuracy, limit of detection and limit of quantification, carry-over and matrix effects. All the evaluated parameters were found within the established confines. The method was able to quantify small amounts of both COMT isoforms in complex samples such as cell lysates, showing its applicability. The versatility of the analytical method proposed may allow its application in routine laboratory analysis of SCOMT and MBCOMT in various biological matrices such as blood, breast tissue, liver tissue or brain tissue.
- Assessment of pipette-tip magnetic solid phase extraction for determination of sulfonamides in waterPublication . Medina, Maxell Rafael Rodriguez; Bernardo, Francisco Javier Guzmán; Alba, Maria Eugénia GallardoThe widespread use of sulfonamides, in the population, in hospitals and veterinary medicine has raised concerns about the discharge of these compounds to the environment. The common treatments in wastewater, treatment plants cannot remove these compounds efficiently, which makes them end up in the water bodies, with concerning associated problems such as bacterial resistance. Therefore, it is essential to develop analytical methods that are both sensitive and selective to monitor and determine these compounds in water. A crucial step in the analytical process is the sample preparation, which allows its purification and concentration. Solid phase extraction (SPE) is a commonly used technique for this purpose, but it has several drawbacks such as associated costs, solvent consumption, possible column clogging among others. The development of dispersive modes together with the use of nanoparticles, as sorbents due to their high surface area is an excellent alternative to overcome several limitations in the field of extraction. Additionally, if the nanoparticles used as sorbents are magnetic, the phase separation can be easily carried out with an external magnetic field, this approach is called magnetic solid phase extraction (MSPE). An innovative variant of the MSPE method is pipette-tip magnetic solid phase extraction (PT-MSPE), in which extraction and elution are performed in a pipette tip. Its ability to operate with small volumes of solvents, its speed and efficiency, and its high selectivity and sensitivity make it ideal for a wide range of analytical applications. Furthermore, its alignment with sustainability principles reinforces its attractiveness in the development of modern and environmentally responsible analytical methods. This work presents an innovative method for the determination of four sulfonamides in water, sulfamethoxazole (SMX), sulfathiazole (STZ), sulfamethoxypyridazine (SMP) and sulfamethazine (SMT), using magnetic nanoparticles embedded in a selective commercial sorbent by PT-MSPE prior to determination by liquid chromatography and ultraviolet detection. The PT-MSPE method was provided limits of detection and quantification of 0.78-2.6 µg L-1 and 6-20 µg L-1 , and enrichment factors up to 6.6. Also, it was positively evaluated by three environmental impact assessment tools of analytical processes.
- Avaliação comparativa da qualidade microbiológica às diferentes categorias de Géneros Alimentícios definidos pelo Instituto Nacional de Saúde Doutor Ricardo JorgePublication . Brito, Renata Esteves; Trindade, Joana Alexandra RodriguesO sistema de gestão de segurança alimentar em Portugal é implementado sob medidas preventivas como as Boas Práticas de Higiene e Fabrico e a aplicação do plano HACCP. Na validação destes métodos, é fundamental análises microbiológicas frequentes, que permitem verificar a correta implementação dos Pontos Críticos de Controlo. Os instrumentos de avaliação das análises microbiológicas estão contidos nos “Valores-guia INSA”, publicado pelo Instituto Nacional de Saúde Doutor Ricardo Jorge. Neste documento os alimentos prontos para consumo estão agrupados em 4 grupos distintos. No presente Relatório de Estágio, é realizada uma avaliação comparativa da qualidade microbiológica aos grupos 1, 2 e 3, que dizem respeito a: alimentos totalmente confecionados; alimentos confecionados com a adição de componentes crus e alimentos crus, respetivamente. Como amostras foram utilizados os resultados de dois tipos de alimentos, para cada grupo: arroz branco e sopa (grupo 1); sushi e sandes de presunto ou chouriço (grupo 2) e saladas e sumos (grupo 3). Na análise geral dos resultados e para os diferentes parâmetros microbiológicos, os alimentos com maior quantidade de resultados Nãosatisfatório foi o arroz branco, mas o grupo com pior perfil de resultados foi o grupo 2. Destes três alimentos o parâmetro mais preocupante foi a contagem de Staphylococcus coagulase-positiva. Dos seis alimentos estudados, apenas três obtiveram amostras Nãosatisfatórias na contagem de E. coli, mas nenhum acima de 3%. Foi também incluído neste Relatório um estudo relativo à evolução dos resultados ao longo de 5 anos (2019 até abril de 2023), do qual se concluiu uma evolução positiva na Segurança Alimentar nos três grupos estudados, todos com um espetro de aumento de resultados Satisfatórios e diminuição dos resultados Não-satisfatórios. Foi também notório um padrão na diminuição de resultados Satisfatórios no ano 2020, em todos os grupos. Esta diminuição poderá, ou não, estar relacionada com a instalação da pandemia COVID-19, sendo esta uma hipótese regulatória. Podemos concluir que resultados sugerem que a implementação de medidas preventivas de SA, está a ser bem-sucedida, mostrando uma contribuição positiva para a segurança e saúde pública.