Browsing by Author "Ribeiro, Ilda P."
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- Cytotoxicity assessment of endodontic sealers: metabolic activity, morphology and chromosomal alterationsPublication . Tavares, Inês Moura; Ribeiro, Ilda P.; Pais, Cláudia; Laranjo, Mafalda; Jardim, Ana; Mascarenhas, Alexandra; Zuzarte, Mónica; Cardoso, Miguel; Girão, Henrique; Botelho, Maria Filomena; Melo, Joana B. de; Carreira, Isabel M.; Noites, RitaIntroduction: Endodontic treatment aims to eliminate infection of the root canals and fill the dental pulp space, being, the obturation of root canals an important step. The study of the toxicity/biocompatibility of the sealers used to fill the root canals is crucial since they are applied into direct contact with periradicular tissues.There are several types of sealers, categorized according to their main chemical constituents. The aim of this study was to evaluate the cytotoxicity of three root canal sealers, AH Plus, Bio MTA+ and Bio C, on immortalized human gingival fibroblasts. Methods: To study the cytotoxicity of the sealers we performed a Methyltetrazolium (MTT) assay, a study of cell's morphology and a cytogenetic study. Cells were placed in contact with material-conditioned media, for 24 h, at three different concentrations (1, 10 and 100 mg/ml) for the MTT assay. Cell morphology and cytogenetic studies were performed at 100 mg/ml. Cells in normal culture medium were analyzed as control group. Results: MTT assay revealed a cytotoxic effect of Bio MTA+ and Bio C with a growing decrease of metabolic activity with increasing compound concentration, reaching 50% with 100 mg/ml. Regarding the cells morphology, Bio C was the compound that showed a more drastic effect, with a decrease in cell confluence and several morphological changes. AH Plus and Bio MTA+ did not seem to affect the cell confluence, however morphology changes were observed, as compromised cell membranes and loss of cell content. Cytogenetic study was thus far only performed with AH Plus. Since there was a severe decrease of mitotic index after treatment, it was not yet possible to obtain sufficient metaphases, even after several cytogenetic harvesting procedures, but, so far, no relevant structural or numerical changes were observed. Discussion: This preliminary study allowed us to verify that these root canal sealers exhibit some cytotoxicity, depending on the concentration used. Although more studies are still needed, this work could be important to both, help in the selection of the most appropriate compounds for clinical practice and to determine the maximum recommended amounts of each sealer.
- Influence of genetic variants of oxidative stress related genes on prognosis and therapy response in chronic myeloid leukemiaPublication . Alves, Raquel; Ventura, Filipa; Jorge, Joana; Ribeiro, Ilda P.; Marques, Gilberto; Coucelo, Margarida; Diamond, Joana; Freitas-Tavares, Paulo; Almeida, António; Goncalves, Ana Cristina; Sarmento-Ribeiro, Ana BelaChronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by the presence of BCR-ABL1 oncogene. Oxidative stress conditions are crucial in tumor development and progression. The NRF2, codified by NFE2L2 gene, plays a central role in redox balance, promoting the transcription of cytoprotective and antioxidant genes such as SOD2, GPX1 and CAT. The action of this transcription factor is regulated by KEAP1. Alterations in these genes, either due to somatic mutations or genetic variants (SNV), have been associated with the development, prognosis, and therapeutic response in cancer. This work evaluated the influence of polymorphisms in genes associated with oxidative stress (NFE2L2, KEAP1, SOD2, GPX1, and CAT) in prognosis and treatment response with tyrosine kinase inhibitors (TKI) in CML patients. In 194 CML samples, nine genetic variants in NFE2L2 (rs6721961, rs4893819, rs35652124, rs6706649 and rs13001694), KEAP1 (rs113540846), SOD2 (rs4880), GPX1 (rs1050450) and CAT (rs1001179) were genotyped by PCR based assays. The association of these genetic variants with clinical-laboratory characteristics were assessed by Fisher’s test, logistic regression, and Kaplan-Meier curves, considering a p<0.05. The results obtained showed that patients with G allele on GPX1 rs1050450 and KEAP1 rs113540846 variants have an approximately 2-fold and 31-fold higher probability of being TKI resistant, respectively. In TKI-resistant group, patients with CT genotype in NFE2L2 rs4893819 variant were more likely to need three or more lines of treatment (OR=5.60, 95%CI 1.22-25.75, p=0.027). An important factor for TKI response is BCR-ABL1 mutational status, and we found that individuals with AG genotype in NFE2L2 rs13001694 present, approximately 9x more risk of mutation on this fusion gene. Moreover, patients heterozygous for the NFE2L2 rs4893819 (CT genotype) and SOD2 rs4880 (AG genotype) variants have faster disease progression [NFE2L2: hazard ratio (HR)=7.84, 95% CI 1.82-29.93, p=0.020; SOD2: HR=7.19, 95% CI 1.62-31.96, p=0.035] comparing with other genotypes. While the GG genotype of the NFE2L2 rs13001694 variant has a 2-fold lower overall survival than other patients (HR=11.86, 95% CI 1.39-1000.7, p=0.023). Additionally, we also observed an association between haplotypes and genotypic profile with CML prognosis. In conclusion, our results suggest that genetic variants in genes associated with the redox state might be important factors in the prognosis, survival, and therapy response in CML patients.