Browsing by Author "Ribeiro-Varandas, Edna"
Now showing 1 - 10 of 11
Results Per Page
Sort Options
- Bisphenol A alters transcript levels of biomarker genes for major depressive disorderPublication . Ribeiro-Varandas, Edna; Pereira, H. Sofia; Viegas, Wanda; Delgado, MargaridaMajor depressive disorder is a moderately heritable disorder characterized by one or more major depressive episodes. Laboratory tests to suport MDD diagnosis are not available. Diagnosis and treatment are based on various signs and symptoms not always fitting into strict diagnostic categories. Research for biological markers of neuropsychiatric disorders has been a challenge.
- Bisphenol A alters transcript levels of biomarker genes for major depressive disorder in vascular endothelial cells and colon cancer cellsPublication . Ribeiro-Varandas, Edna; Pereira, H. Sofia; Viegas, Wanda; Delgado, MargaridaBisphenol A (BPA) is capable of mimicking endogenous hormones with potential consequences for human health and BPA exposure has been associated with several human diseases including neuropsychiatric disorders. Here, quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) results show that BPA at low concentrations (10 ng/mL and 1 μg/mL) induces differential transcript levels of four biomarker genes for Major Depressive Disorder (MDD) in HT29 human colon adenocarcinona cell line and Human Umbilical Vein Endothelial Cells (HUVEC). These results substantiate increasing concerns of BPA exposure in levels currently detected in humans.
- Bisphenol A at the reference level counteracts doxorubicin transcriptional effects on cancer related genes in HT29 cellsPublication . Delgado, Margarida; Ribeiro-Varandas, EdnaHuman exposure to Bisphenol A (BPA) results mainly from ingestion of food and beverages. Information regarding BPA effects on colon cancer, one of the major causes of death in developed countries, is still scarce. Likewise, little is known about BPA drug interactions although its potential role in doxorubicin (DOX) chemoresistance has been suggested. This study aims to assess potential interactions between BPA and DOX on HT29 colon cancer cells. HT29 cell response was evaluated after exposure to BPA, DOX, or co-exposure to both chemicals. Transcriptional analysis of several cancer-associated genes (c-fos, AURKA, p21, bcl-xl and CLU) shows that BPA exposure induces slight up-regulation exclusively of bcl-xl without affecting cell viability. On the other hand, a sub-therapeutic DOX concentration (40 nM) results in highly altered c-fos, bcl-xl, and CLU transcript levels, and this is not affected by co-exposure with BPA. Conversely, DOX at a therapeutic concentration (4 μM) results in distinct and very severe transcriptional alterations of c-fos, AURKA, p21 and CLU that are counteracted by co-exposure with BPA resulting in transcript levels similar to those of control. Co-exposure with BPA slightly decreases apoptosis in relation to DOX 4 μM alone without affecting DOX-induced loss of cell viability. These results suggest that BPA exposure can influence chemotherapy outcomes and therefore emphasize the necessity of a better understanding of BPA interactions with chemotherapeutic agents in the context of risk assessment.
- Bisphenol A at the reference level counteracts doxorubicin transcriptional effects on cancer related genes in HT29 cellsPublication . Delgado, Margarida; Ribeiro-Varandas, EdnaHuman exposure to Bisphenol A (BPA) results mainly from ingestion of food and beverages. Information regarding BPA effects on colon cancer, one of the major causes of death in developed countries, is still scarce. Likewise, little is known about BPA drug interactions although its potential role in doxorubicin (DOX) chemoresistance has been suggested. This study aims to assess potential interactions between BPA and DOX on HT29 colon cancer cells. HT29 cell response was evaluated after exposure to BPA, DOX, or co-exposure to both chemicals. Transcriptional analysis of several cancer-associated genes (c-fos, AURKA, p21, bcl-xl and CLU) shows that BPA exposure induces slight up-regulation exclusively of bcl-xl without affecting cell viability. On the other hand, a sub-therapeutic DOX concentration (40nM) results in highly altered c-fos, bcl-xl, and CLU transcript levels, and this is not affected by co-exposure with BPA. Conversely, DOX at a therapeutic concentration (4μM) results in distinct and very severe transcriptional alterations of c-fos, AURKA, p21 and CLU that are counteracted by co-exposure with BPA resulting in transcript levels similar to those of control. Co-exposure with BPA slightly decreases apoptosis in relation to DOX 4μM alone without affecting DOX-induced loss of cell viability. These results suggest that BPA exposure can influence chemotherapy outcomes and therefore emphasize the necessity of a better understanding of BPA interactions with chemotherapeutic agents in the context of risk assessment.
- Efeitos do xenoestrógeneo Bisfenol A no envelhecimento celularPublication . Ribeiro-Varandas, Edna; Pereira, H. Sofia; Viegas, Wanda; Delgado, Margarida; Escola Superior de Tecnologia da Saúde de LisboaO Bisphenol A (BPA) é um xenoestrógeneo sintético capaz de ativar diversas vias de sinalização associadas a estrogénios. Este composto é utilizado na produção de plástico e das resinas de cola Epoxy, encontrando-se presente numa grande variedade de produtos para consumo humano. Consequentemente a exposição humana ao BPA é considerada generalizada e contínua. Estudos epidemiológicos verificaram correlação entre níveis elevados de BPA na urina e patogénese de doenças associadas ao envelhecimento celular como a aterosclerose. Neste estudo foram avaliados os efeitos da exposição prolongada ao BPA de concentrações encontradas em amostras biológicas humanas associadas a exposição ambiental e ocupacional, nomeadamente 10 ng/mL e 1 μg/ml.
- Endocrine disruptors mixtures: the real scenario of human exposurePublication . Ribeiro-Varandas, Edna; Ladeira, Carina; Viegas, SusanaEndocrine disrupting chemicals (EDCs) are exogenous agents that have the ability to interfere with/or mimic estrogenic hormones and, therefore can simultaneously and differentially trigger specific signaling pathways responsible for the nature and magnitude of biological responses in diverse cell types. Human exposure to EDCs, particularly at low-doses, is ubiquitous, persistent and occurs in complex mixtures. These compounds can bioaccumulate in lipid compartments of tissues forming a mixed “body burden” of contaminants of different origins. Although the independent action of chemicals has been considered the main principle in EDCs mixture toxicity, several effects cannot be predicted when analyzing single compounds individually. Based in a revision of the literature, focused in studies that evaluated EDCs mixtures, we hypothesize the scenario of a pregnant woman environmentally exposed to three different EDCs as a potential real scenario of human exposure supported by data describing where exposure to these compounds occur.
- Job satisfaction of bioscientists at a Lisbon hospitalPublication . Leitão, Maria do Céu; Abreu, Renato; Bellém, Fernando; Almeida, Ana; Ribeiro-Varandas, Edna; Tavares, Ana SofiaProfessional satisfaction is an important phenomenon due to its influence on the human mental resources and physical health, on their attitudes and on their behaviour, both professional and social. The purpose of this study is to assess the actual level of professional satisfaction of bioscientists working at a Lisbon hospital. A modified questionnaire which allowed the data collection was used for each subject, intended to characterize the sample, order the eight dimensions of professional satisfaction as well determining their levels by using a satisfaction scale. A statistical analysis was made by descriptive methods, Friedman test, Student’s t-test for independent samples and one-way ANOVA. In a sample of 30 technicians (25.42 % of the target-population), the most important dimension was Status/Prestige (7.12) and the least important was Remuneration (3.12). Global satisfaction shows that they are neither satisfied nor dissatisfied, although the dimension Professional-Patient Relation had better results, in opposition to Remuneration, which had the worst outcome. The study concluded that the sample’s level of professional satisfaction is not affected by gender, qualifications, years of technical experience and remuneration. The results reveal a state of accommodation and lack of interest regarding labor, which might be a consequence of the actual stagnation in their career. The replication of this study in other public and private institutions are of the most relevance, in order to obtain representative outcomes concerning the professional satisfaction of bioscientists at a national level.
- Low-dose effects of Bisphenol A on human primary and cancer cellsPublication . Ribeiro-Varandas, EdnaBisphenol A (BPA), 2,2-bis(4-hydroxyphenyl) propane is an organic compound and one of the greatest volume industrial chemicals produced worldwide. Human exposure to BPA, in the range of the called “low-doses”, is considered a generalized phenomenon particularly through oral intake. Biomonitoring studies reveal the presence of BPA in the majority of the individuals from developed countries. BPA is a well characterized endocrine disruptor which can endorse very distinct cellular responses through several estrogen receptor signalling pathways frequently associated to cell type specificities. Extensive research in human cell lines from sex hormone responsive tissues have demonstrated the potential harmful effects of BPA exposure including carcinogenesis. However, although BPA is absorbed in the gut and enters blood circulation, its effects on cells from digestive or vascular systems are largely unknown. There is an urgent need to address increasing concerns regarding the potential adverse effects of BPA low-dose exposures and to evaluate potential interactions in the context of human health risk assessment.
- O paradigmático Bisfenol A: exposição humana ambiental e ocupacional e efeitos associadosPublication . Ribeiro-Varandas, EdnaOs desreguladores endócrinos (EDCs) são uma importante preocupação para a saúde humana devido aos seus potenciais efeitos negativos. Por definição, os EDCs têm a capacidade de interferir com a sinalização hormonal através da sua capacidade de ligação aos recetores hormonais e, deste modo, afetar o normal funcionamento do sistema endócrino. O sistema endócrino regula a transcrição génica através de moléculas sinalizadoras, hormonas, que atuam em baixas concentrações. Assim, a exposição a EDCs, mesmo em baixas doses, pode ter efeitos biológicos adversos. Entre os EDCs, o 4,4'-isopropylidene diphenol (Bisphenol A:BPA) destaca-se como um caso paradigmático de um xenoestrógeneo sintético, utilizado na produção de plásticos e das resinas de cola Epoxy, encontrando-se presente numa grande variedade de produtos para consumo humano. Estudos epidemiológicos têm revelado correlações positivas entre a presença de BPA em amostras biológicas humanas e a ocorrência de várias patologias, como infertilidade e desregulação do sistema reprodutivo, diabetes Mellitus tipo II e obesidade.
- Study of biochemical and haematological changes in football playersPublication . Tavares, Ana Sofia; Almeida, Ana; Leitão, Maria do Céu; Ribeiro-Varandas, Edna; Abreu, Renato; Bellém, FernandoBackground - Football players develop throughout their practice, an endurance type exercise. This type of practice is known to cause changes both at the cellular level as well as on muscle enzymes. Modifications are also seen in terms of lipid profile, caused by the faster rate of metabolism of these molecules. The aim of this paper was to study the variation of biochemical and haematological parameters on football players. Methods - Blood samples were drawn from 18 football players undergoing an 8 hour-a-week training program. The following parameters were tested: lipid profile, creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST); red blood cells (RBC) and their indices, haemoglobin and haematocrit. Results - The lipid profile showed that the HDL-Cholesterol mean (=53.33 mg/dL) was above the value determined as a target (37.00 mg/dL). The LDL-Cholesterol mean was below the target-value, as it was for the triglycerides. There were no significant differences between the real mean and the target value for total cholesterol. All creatine kinase (CK) values were above the target-value of 77 UI/L. The values obtained for lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) tests did not show any significant difference from targetvalues. No major differences from the target values were seen in terms of the haematological parameters. Conclusions - The results of this study have shown that the practice of physical exercise has caused a modification in the subject's lipid profile, especially on the HDL-C values. Concerning muscle enzymes, the only altered value found was for creatine kinase (CK). The so called sports anaemia was not confirmed.