Browsing by Author "Ramos, Carina"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Assessment of DNA damage and oxidative stress of green tea epigallocatechin-3-gallate (EGCG) by comet assayPublication . Ladeira, Carina; Ramos, Carina; Pádua, Mário; Ribeiro, EdnaIntroduction: EGCG, the primary polyphenol in green tea, has been shown to inhibit cancer cell growth and tumorigenesis in vitro and animal models, particularly by eliminating cancer cells through induction of apoptosis and protecting normal cells against genotoxic hazards. However, increasing evidence indicates that EGCG produces ROS. Aim of the study: Evaluate DNA damage and oxidative damage, measured by comet assay; lipid profile, liver function parameters, and vitamins A and E levels during an interventional study with 90 days (T0 and T90) duration (T0 and T90) in 30 individuals with an EGCG intake of 225 mg/day.
- Cytotoxic and genotoxic effects of environmental relevant concentrations of bisphenol A and interactions with doxorubicinPublication . Ramos, Carina; Ladeira, Carina; Zeferino, Sofia; Dias, Ana; Faria, Isabel; Cristovam, Elisabete; Gomes, Manuel; Ribeiro, EdnaBisphenol A (BPA) is one of the most widely utilized endocrine disruptors to which humans are exposed, particularity through ingestion. BPA is an aneugenic compound with a putative association to tumorigenesis. Although extensively studied in estrogen-responsive cells, information regarding its effects on cells from the upper gastrointestinal tract exposed to free/active forms of BPA are still scarce. Similarly, BPA interactions with other drugs has been neglected, although it has been suggested to has a potential role in doxorubicin (DOX) chemoresistance. This study is intended to assess potential cytotoxic and genotoxic effects of BPA, as well as its interactions with DOX, in Human epithelial type 2 cells (Hep-2) originated from a human laryngeal carcinoma and in a DNA damage responsive cell line, the human lung fibroblasts (MRC-5). Cell viability was analyzed through the resazurin assay. The G protein-coupled estrogen receptor 1 (GPER) expression was visualized by immunodetection. Genotoxicity, namely DNA damage and oxidative DNA damage, were assessed by comet assay and micronuclei induction, and mitotic disruption was evaluated cytologically by fluorescent microscopy wif DAPI staining. Cytotoxicity analysis showed that exposure to BPA per se does not affect cellular viability. Nevertheless, the genotoxic analysis showed that BPA induced an increase of DNA damage in the Hep-2 cell line and in oxidative damage in the MRC-5 cell line. An increase of micronuclei was also observed in both cell lines following BPA exposure. BPA and DOX co-exposures suggested that BPA acts as an antagonist of DOX effects in both cell lines. The interaction wif DOX appears to be cell type dependent, exhibiting a non-monotonic response curve in MRC-5 cells, a GPER expressing cell line. Our study emphasizes the need for a deeper knowledge of BPA interactions, particularly with chemotherapeutic agents, in the context of risk assessment and public health.
- Green tea epigallocatechin-3-gallate (EGCG) oxidative stress and DNA damagePublication . Ladeira, Carina; Pádua, Mário; Ramos, Carina; Ribeiro, EdnaEpigallocatechin-3-gallate (EGCG) antioxidant properties have been demonstrated however, increasing evidence indicates that EGCG produces reactive oxygen species. The aim of this study was to evaluate the effect of EGCG intake during 90 days in hematological cardiovascular risk factors, vitamins A and E, DNA damage, and oxidative damage in human blood. Peripheral blood from 30 healthy individuals (10 males and 20 females; 18 – 45 years), was collected at time 0 (T0) and time 90 (T90). During 90 days, participants ingested capsules of green tea extract (225mg EGCG) daily. Hematological cardiovascular risk factors including lipid profile and liver function parameters were assessed using colorimetric methods. Vitamins A and E in serum were quantified by HPLC and analysis of DNA damage and oxidative damage was performed by comet assay. Our results showed that lipid profile and liver function parameters are not affected by EGCG and serum levels of vitamin E increased, but not vitamin A. An increase in DNA damage and DNA oxidative damage after 90 days of EGCG consumption was also reported. The results suggest that EGCG can induce DNA damage, possibly due to ROS induction, with an associated increase of the antioxidant vitamin E, however without alteration of hematological cardiovascular risk factors.
- Organic dust exposure in bakeries: assessment of genotoxic effectsPublication . Ladeira, Carina; Ramos, Carina; Viegas, SusanaExposure to organic dust occurs in a range of occupational settings including food industries, such as bakeries and pastry industries. Organic dust consists of particulate matter of microbial, plant or animal origin. Its specific composition depends of the type of setting but can implicate several agents such as viruses, bacteria and Gram-negative bacteria endotoxins, actinomycete, spores from moss, fern or fungi, fungi mycotoxins and glucans, algae or plant cell, enzymes and proteins of plant or animal origin, antibiotics and other products from biotechnological processes, insects and mites (and their fragments and excreta). In bakeries, the flour dust is the main responsible for the organic dust exposure. Flour is a complex organic dust consisting of one or a mixture of several cereal grains (wheat, rye, millet, barley, oats or corn cereal) that have been processed or ground by milling. Moreover, flour may contain a diverse number of contaminants, such as silica, fungi and their metabolites (mycotoxins), bacterial endotoxins, insects, mites, mammalian debris and chemical additives such as pesticides and herbicides. Several studies have already reported respiratory health effects in exposed workers, both in small- and large-scale industries, related to the distinct types of dust generated during the production process. Respiratory system symptoms and diseases induced by occupational dust are influenced by the type of dust, dose, duration of exposure and genetic factors. The aim of this study was to characterize possible genotoxic effects of particulate matter by the measurement of DNA damage by alkaline comet assay in workers from bakeries.