Browsing by Author "Ladeira, Carina"
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- Adaptação de um instrumento de avaliação qualitativa do risco químico em anatomia patológicaPublication . Ferro, Amadeu Borges; Ladeira, Carina; Viegas, Carla; Ribeiro, Cátia; Figueira, Edite; Albuquerque, Paula; Quintino, FernandaOs agentes químicos são frequentemente manipulados nos laboratórios de anatomia patológica. Existem diversos estudos que comprovam a existência de uma associação entre a exposição a produtos químicos e o desenvolvimento de determinadas patologias, demonstrando, assim, a importância da avaliação e monitorização deste tipo de agentes. Pretendeu-se, com este trabalho, caracterizar a exposição dos técnicos de anatomia patológica aos agentes químicos através de um instrumento baseado no International Chemical Control Toolkit, no serviço de histopatologia dos laboratórios de anatomia patológica da região de Lisboa e Vale do Tejo.
- Alkaline comet assay in DNA damage assessment in frozen whole blood samples without cryopreservation: results of the hCOMET GroupPublication . Milić, M.; Collins, A.; Koppen, G.; Azqueta Oscoz, A.; Langie, S.; Basaran, N.; Møller, P.; Giovanelli, L.; Ladeira, Carina; Gajski, G.; Gerić, M.As a worldwide-used, simple, sensitive, and inexpensive technique, alkaline comet assay can give reliable results in the assessment of strand breaks (SBs) and alkali-labile sites. In human biomonitoring, fresh blood samples (whole blood, isolated mononuclear cells, and their cell fractions) are usually used, but the assay can be used also on cryo-preserved samples of freshly isolated peripheral blood mononuclear cells (PBMC). When processing a large number of whole blood samples into isolated PBMC ready for freezing, this process can be time-consuming, and cryo-preservatives (dimethyl sulfoxide/glycerol) can harm cells and increase DNA damage levels after thawing. The need has emerged to develop a relatively simple protocol that can be applied immediately even to small volumes of stored frozen whole blood without the cryopreservative. The presentation will show the findings from our hCOMET group demonstrating new protocols using smaller whole blood volumes (250 μl-1 ml) for freezing, fast thawing with normal comet assay conditions (5–10 μl sample, 0.5−0.6% agarose layer, counting nucleoids only in the slides central part avoiding edges) that demonstrated reproducible results with freezing conditions of up to three months but also, even more, one or few years. Oxidative measurements after 11 months of blood storage at −80° C demonstrated also promising and comparable results. These findings could be useful in retrospective studies, in future prospective studies, and to re-analyze putative outliers in the dataset.
- Alternativas ao xileno como agente desparafinante: solução de limão 95%, solução de detergente 1,5% e da solução de detergente e limãoPublication . Trittoni, A.; Mendes, A.; Malhão, B.; Pires, C.; Luchian, C.; Fortunato, I.; Alves, Sara; Paulino, T.; Ladeira, CarinaO xilol, também denominado xileno, é utilizado nos laboratórios de anatomia patológica durante o processamento, na diafanização, e na etapa da coloração de hematoxilina eosina, como agente desparafinante É um composto orgânico volátil que a curto prazo pode provocar irritação da pele, olhos, nariz, garganta, dificuldade em respirar, entre outros Além dos efeitos apresentados, uma exposição a curto e a longo prazo a altas concentrações de xileno podem ter vários efeitos no sistema nervoso, como dores de cabeça, tonturas, confusão, entre outros efeitos É por isso, de extrema importância reduzir a sua utilização ou substituir por outros solventes que tenham funções semelhantes. Objetivo do estudo: Com o objetivo de reduzir a sua exposição, testou se a eficácia de soluções alternativas na etapa da desparafinação da coloração por hematoxilina eosina.
- Application of alkaline comet assay in human biomonitoring for genotoxicity: a study on occupational exposure to cytostaticsPublication . Ladeira, Carina; Viegas, Susana; Carolino, Elisabete; Gomes, M. C.; Brito, MiguelThe use of cytostatics drugs in anticancer therapy is increasing. Health care workers can be occupationally exposed to these drugs classified as carcinogenic, mutagenic or teratogenic. Cytostatics drugs are a heterogeneous group of chemicals widely used in the treatment of cancer, nevertheless have been proved to be also mutagens, carcinogens and teratogens. Workers may be exposed to this drug, being in the hospital settings the main focus dwelled upon the pharmacy, and nursing personnel. Alkaline comet assay is one of the most promising short-term genotoxicity assays for human risk assessment, being recommended to monitor populations chronically exposed to genotoxic agents. DNA glycosylase (OGG1) represents the main mechanism of protecting the integrity of the human DNA with respect to 8-OHdG, the most well studied biomarker of oxidative damage.
- Application of human biomonitoring programmes in occupational exposure contexts: an overviewPublication . Ladeira, Carina; Viegas, SusanaHuman biomonitoring consists, in one hand by the research and investigation of environmental hazards and, in other hand in risk estimating of developing cancer by exposure to those conditions. Since carcinogenesis is a process that takes time, the biomarkers applied to recognize abnormal biological events have been developed in molecular epidemiological studies. The biomarkers allow the quantification and identification of the progression of normal to abnormal biological conditions at a molecular level. In general, biomarkers can be classified in exposure, effect and genetic susceptibility. Genotoxicity biomarkers are a sub-type of effect biomarkers and are widely used in the assessment of genomic effects caused by exposure – environmental or occupational, being considered predictors of carcinogenesis development. Taken together, and inserted in a biomonitoring program, probably is the most growing tool available nowadays for the prevention of health effects from occupational exposure to chemicals. Ethical considerations should always be taken into consideration in the planning and implementation of the biomarkers involved.
- Application of the comet assay in human biomonitoring: an hCOMET perspectivePublication . Azqueta, Amaya; Ladeira, Carina; Giovannelli, Lisa; Boutet-Robinet, Elisa; Bonassi, Stefano; Neri, Monica; Gajski, Goran; Duthie, Susan; Del Bo’, Cristian; Riso, Patrizia; Koppen, Gudrun; Basaran, Nursen; Collins, Andrew; Møller, PeterThe comet assay is a well-accepted biomonitoring tool to examine the effect of dietary, lifestyle, environmental and occupational exposure on levels of DNA damage in human cells. With such a wide range of determinants for DNA damage levels, it becomes challenging to deal with confounding and certain factors are interrelated (e.g. poor nutritional intake may correlate with smoking status). This review describes the effect of intrinsic (i.e. sex, age, tobacco smoking, occupational exposure, and obesity) and extrinsic (season, environmental exposures, diet, physical activity, and alcohol consumption) factors on the level of DNA damage measured by the standard or enzyme-modified comet assay. Although each factor influences at least one comet assay endpoint, the collective evidence does not indicate single factors have a large impact. Thus, controlling for confounding may be necessary for a biomonitoring study, but none of the factors is strong enough to be regarded as a priori as a confounder. Controlling for confounding in the comet assay requires a case-by-case approach. Inter-laboratory variation in levels of DNA damage and to some extent also reproducibility in biomonitoring studies are issues that have haunted the users of the comet assay for years. Procedures to collect specimens, and their storage, are not standardized. Likewise, statistical issues related to both sample-size calculation (before sampling of specimens) and statistical analysis of the results vary between studies. This review gives guidance to statistical analysis of the typically complex exposure, co-variate, and effect relationships in human biomonitoring studies.
- Assessing the impact of nanoplastics in biological systems: systematic review of in vitro animal studiesPublication . Viana, Maria; Tonin, Fernanda; Ladeira, CarinaNanoplastic (NP) pollution has emerged as a growing concern due to its potential impact on human health, although its adverse effects on different organ systems are not yet fully understood. This systematic scoping review, conducted following international guidelines, aimed to map the current evidence on the biological effects of NPs. In vitro animal studies assessing cellular damage caused by exposure to any type of NP were searched on PubMed, Web of Science, and Scopus. Data on primary outcomes related to genotoxicity and cytotoxicity (cell viability, oxidative stress, inflammation, DNA and cytoplasmic damage, apoptosis) were extracted from the included studies, and overall reporting quality was assessed. A total of 108 articles published between 2018 and 2024, mostly by China (54%), Spain (14%), and Italy (9%), were included. Polystyrene (PS) was the most frequently studied polymer (85%). NP sizes in solution ranged from 15 to 531 nm, with a higher prevalence in the 40–100 nm range (38%). The overall quality of studies was rated as moderate (60%), with many lacking essential details about cell culture conditions (e.g., pH of the medium, passage number, substances used). A higher frequency of negative effects from NP exposure was observed in respiratory cell lines, while immune, digestive, and hepatic cell lines showed greater resistance. Nervous, urinary, and connective tissue systems were impacted by NPs. Positively charged and smaller PS particles were consistently associated with higher toxicity across all systems. In summary, this review highlights the multifactorial nature of NP toxicity, influenced by size, surface charge, and polymer type. It also reveals a significant knowledge gap, stemming from the predominant use of immortalized monocultures exposed to commercially available PS NPs, the limited use of environmentally relevant particles, and the underutilization of advanced experimental models (e.g., organ-on-chip systems) that better mimic physiological conditions.
- 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.
- Assessment of genotoxic effects in nurses handling cytostatic drugsPublication . Ladeira, Carina; Viegas, Susana; Pádua, Mário; Gomes, Mário; Carolino, Elisabete; Gomes, M. C.; Brito, MiguelSeveral antineoplastic drugs have been classified as carcinogens by the International Agency for Research on Cancer (IARC) on the basis of epidemiological findings, animal carcinogenicity data, and outcomes of in vitro genotoxicity studies. 5-Fluorouracil (5-FU), which is easily absorbed through the skin, is the most frequently used antineoplastic agent in Portuguese hospitals and therefore may be used as an indicator of surface contamination. The aims of the present investigation were to (1) examine surface contamination by 5-FU and (2) assess the genotoxic risk using cytokinesis-block micronucleus assay in nurses from two Portuguese hospitals. The study consisted of 2 groups: 27 nurses occupationally exposed to cytostatic agents (cases) and 111 unexposed individuals (controls). Peripheral blood lymphocytes (PBL) were collected in order to measure micronuclei (MN) in both groups. Hospital B showed a higher numerical level of contamination but not significantly different from Hospital A. However; Hospital A presented the highest value of contamination and also a higher proportion of contaminated samples. The mean frequency of MN was significantly higher in exposed workers compared with controls. No significant differences were found among MN levels between the two hospitals. The analysis of confounding factors showed that age is a significant variable in MN frequency occurrence. Data suggest that there is a potential genotoxic damage related to occupational exposure to cytostatic drugs in oncology nurses.
- Assessment of genotoxicity of aflatoxin M1 and B1 contaminated milks after in vitro human digestionPublication . Ladeira, Carina; Becker-Algeri, Tania Aparecida; Pimenta, Andreia Isabel; Badiale-Furlong, ElianaIntroduction - Milk is considered a complete food from the nutritional point of view. Milk can be exposed to various types of contamination, such as mycotoxins. These metabolites are naturally occurring toxic compounds produced by fungi. Several studies on milk samples have reported the presence of aflatoxin B1 (AFB1) and M1 (AFM1), due to the high incidence in samples intended for human consumption, carcinogenicity proven AFB1 and resistance of the contaminants to the process of digestion, making those available for intestinal absorption. Considering these aspects, the objective of this study was to evaluate the genotoxicity of milk samples contaminated by AFB1 and AFM1 before and after the action of lactic acid bacteria using Caco-2 intestinal human cells.