Browsing by Author "Marques, M"
Now showing 1 - 6 of 6
Results Per Page
Sort Options
- Abordagem multidisciplinar na Patologia Mamária IncomumPublication . Marques, M; Branco, R
- Differences in nevirapine biotransformation as a factor for its sex-dependent dimorphic profile of adverse drug reactions.Publication . Marinho, A; Rodrigues, P; Caixas, U; Antunes, A; Branco, T; Hargivan, S; Marques, M; Monteiro, E; Pereira, SOBJECTIVES: Nevirapine is widely used for the treatment of HIV-1 infection; however, its chronic use has been associated with severe liver and skin toxicity. Women are at increased risk for these toxic events, but the reasons for the sex-related differences are unclear. Disparities in the biotransformation of nevirapine and the generation of toxic metabolites between men and women might be the underlying cause. The present work aimed to explore sex differences in nevirapine biotransformation as a potential factor in nevirapine-induced toxicity. METHODS: All included subjects were adults who had been receiving 400 mg of nevirapine once daily for at least 1 month. Blood samples were collected and the levels of nevirapine and its phase I metabolites were quantified by HPLC. Anthropometric and clinical data, and nevirapine metabolite profiles, were assessed for sex-related differences. RESULTS: A total of 52 patients were included (63% were men). Body weight was lower in women (P = 0.028) and female sex was associated with higher alkaline phosphatase (P = 0.036) and lactate dehydrogenase (P = 0.037) levels. The plasma concentrations of nevirapine (P = 0.030) and the metabolite 3-hydroxy-nevirapine (P = 0.035), as well as the proportions of the metabolites 12-hydroxy-nevirapine (P = 0.037) and 3-hydroxy-nevirapine (P = 0.001), were higher in women, when adjusted for body weight. CONCLUSIONS: There was a sex-dependent variation in nevirapine biotransformation, particularly in the generation of the 12-hydroxy-nevirapine and 3-hydroxy-nevirapine metabolites. These data are consistent with the sex-dependent formation of toxic reactive metabolites, which may contribute to the sex-dependent dimorphic profile of nevirapine toxicity.
- Evidence for nevirapine bioactivation in man: Searching for the first step in the mechanism of nevirapine toxicity.Publication . Caixas, U; Antunes, A; Marinho, A; Godinho, A; Grilo, N; Marques, M; Oliveira, M; Branco, T; Monteiro, E; Pereira, SNevirapine (NVP) is a non-nucleoside reverse transcriptase inhibitor used against human immunodeficiency virus type-1 (HIV-1), mostly to prevent mother-to-child HIV-1 transmission in developing countries. Despite its clinical efficacy, NVP administration is associated with a variety of toxic responses that include hepatotoxicity and skin rash. Although the reasons for the adverse effects of NVP administration are still unclear, increasing evidence supports the involvement of metabolic activation to reactive electrophiles. In particular, Phase II activation of the NVP metabolite 12-hydroxy-NVP is thought to mediate NVP binding to bionucleophiles, which may be at the onset of toxicity. In the present study, we investigated the nature and specific locations of the covalent adducts produced in human serum albumin and human hemoglobin by reaction in vitro with the synthetic model electrophile 12-mesyloxy-NVP, used as a surrogate for the Phase II metabolite 12-sulfoxy-NVP. Multiple sites of modification were identified by two different mass spectrometry-based methodologies, liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) and matrix-assisted laser desorption ionization tandem mass spectrometry (MALDI-TOF-TOF-MS). These two distinct methodologies, which in some instances afforded complementary information, allowed the identification of multiple adducts involving cysteine, lysine, tryptophan, histidine, serine, and the N-terminal valine of hemoglobin. Tryptophan, which is not a common site of covalent protein modification, was the NVP-modified amino acid residue detected in the two proteins and consistently identified by both LC-ESI-MS/MS and MALDI-TOF-TOF-MS. The propensity of tryptophan to react with the NVP-derived electrophile is further emphasized by the fact that human serum albumin possesses a single tryptophan residue, which suggests a remarkable selectivity that may be useful for biomonitoring purposes. Likewise, the NVP adduct with the terminal valine of hemoglobin, detected by LC-ESI-MS/MS after N-alkyl Edman degradation, appears as an easily assessed marker of NVP binding to proteins. Our results demonstrate the merits and complementarity of the two MS-based methodologies for the characterization of protein binding by NVP and suggest a series of plausible biomarkers of NVP toxicity that should be useful in the monitoring of toxicity effects in patients administered NVP.
- Interrupção voluntária da gravidez - correlação dos achados pré-natais e post-mortemPublication . Caeiro, F; Branco, R; Marques, M; Santos, I; Ferreira, AP; Fonseca, J; Santos, AP; Matos, FA interrupção voluntária da gravidez (IVG) é uma situação de elevada complexidade a vários níveis, implicando um diagnóstico pré-natal preciso e uma corroboração post-mortem do mesmo, com eventual acréscimo de informação que contribua para um adequado aconselhamento genético aos casais. Os autores pretenderam avaliar a qualidade de diagnóstico pré-natal efectuado no seu centro, estudando a população submetida a IVG, nomeadamente identificando as suas indicações/causas e avaliando os exames feto-patológicos para estabelecer uma concordância entre os achados pré-natal e post-mortem. Foram analisados retrospectivamente 84 casos, no período de Janeiro de 2012 a Junho de 2016. A idade média materna foi de 32 anos, sendo maior no grupo das IVG’s por cromossomopatias, com significado estatístico. A mediana da idade gestacional na IVG foi de 18 semanas, sendo que apenas 5% se realizaram após as 24 semanas. A distribuição das causas de IVG foi feita por 4 grupos: cromossomopatias 47,5%, malformações fetais 35,5%, outras causas fetais 12% e causas maternas 6%. Foi estabelecida uma concordância entre os achados pré-natais e os post-mortem no grupo das malformações fetais e outras causas fetais de 66%. Estes resultados estão de acordo com publicações nesta área, corroborando a importância da complementaridade dos achados ecográficos pré-natais com a avaliação minuciosa anatomo-patológica, nomeadamente nas situações de malformações fetais não associadas a cromossomopatia, de modo a obter diagnósticos mais precisos e melhor aconselhamento genético.
- Phenotype-genotype profiles in Crohn's disease predicted by genetic markers in autophagy-related genes (GOIA study II).Publication . Durães, C; Machado, J; Portela, F; Rodrigues, S; Lago, P; Cravo, M; Ministro, P; Marques, M; Cremers, I; Freitas, J; Cotter, J; Tavares, L; Matos, L; Medeiros, I; Sousa, R; Ramos, J; Deus, JR, et al.BACKGROUND: About 70 loci are associated with susceptibility to Crohn's disease (CD), particularly in pathways of innate immunity, autophagy, and pathogen recognition. Phenotype-genotype associations are inconsistent. METHODS: CD susceptibility polymorphisms ATG16L1 rs2241880, ICAM1 rs5498, IL4 rs2070874, IL17F rs763780, IRGM rs13361189, ITLN1 rs2274910, LRRK2 rs11175593, and TLR4 rs4986790 were genotyped in a Portuguese population (511 CD patients, 626 controls) and assessed for association with CD clinical characteristics. RESULTS: There is a significant association of CD with the single nucleotide polymorphisms (SNPs) in ATG16L1 (odds ratio [OR] 1.36 [1.15-1.60], P = 2.7 × 10(-6) for allele G), IRGM (OR 1.56 [1.21-1.93], P = 3.9 × 10(-4) for allele C), and ITLN1 (OR 1.55 [1.28-1.88], P = 4.9 × 10(-4) for allele C). These SNPs are associated with ileal location (OR, respectively, 1.49, 1.52, and 1.70), ileocolonic location (OR, respectively, 1.31, 1.57, and 1.68), and involvement of the upper digestive tract (OR, respectively for ATG16L1 and IRGM, 1.96 and 1.95). The risk genotype GG in ATG16L1 is associated with patients who respond to steroids (OR 1.89), respond to immunosuppressants (OR 1.77), and to biologic therapy (OR 1.89). The SNPs in ITLN1 and IRGM are both associated with a positive response to biologic therapy. The risk for ileal, ileocolonic, and upper digestive tract locations increases with the number of risk alleles (OR for three alleles, respectively, 7.10, 3.54, and 12.07); the OR for positive response to biologic therapy is 3.66. CONCLUSIONS: A multilocus approach using autophagy-related genes provides insight into CD phenotype-genotype associations and genetic markers for predicting therapeutic responses.
- Síndrome dos anticorpos antifosfolipídicos na gravidezPublication . Nascimento, S; Marques, M; Branco, R