Browsing by Author "Godinho, A"
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- Cirurgia na UrgênciaPublication . Rocha, C; Dores, J; Godinho, A; Calado, J; Pinheiro, N
- Dieulafoy’s lesion in Treitz’s anglePublication . Alberto, S; Oro, I; Pires, E; Alves, N; Godinho, A; Figueiredo, A; Deus, JR
- 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.
- Hemorragia intra-pseudoquisto pancreático: apresentando-se como icterícia obstrutivaPublication . Rocha, C; Almeida, S; Leichsenring, C; Calado, J; Godinho, A; Carneiro, FApesar dos avanços no diagnóstico e manuseamento dos pseudoquistos pancreáticos, a incidência de hemorragia intra- -pseudoquisto é entre 6 a 17%. É apresentado um caso clinico de icterícia obstructiva resultante da compressão da via biliar por uma hemorragia intra-pseudoquisto pancreático após rotura de um pseudoaneurisma, diagnosticado por tomografia computorizada, o qual é de rara ocorrência. Pela estabilidade hemodinâmica do doente, a embolização vascular foi a opção terapêutica tendo resultado num tratamento definitivo sem complicações
- High resolution mass spectrometry-based methodologies for identification of Etravirine bioactivation to reactive metabolites: In vitro and in vivo approaches.Publication . Godinho, A; Martins, I; Nunes, J; Charneira, C; Grilo, J; Silva, D; Pereira, S; Soto, K, et al.Drug bioactivation to reactive metabolites capable of covalent adduct formation with bionucleophiles is a major cause of drug-induced adverse reactions. Therefore, elucidation of reactive metabolites is essential to unravel the toxicity mechanisms induced by drugs and thereby identify patient subgroups at higher risk. Etravirine (ETR) was the first second-generation Non-Nucleoside Reverse Transcriptase Inhibitor (NNRTI) to be approved, as a therapeutic option for HIV-infected patients who developed resistance to the first-generation NNRTIs. Additionally, ETR came into market aiming to overcome some adverse effects associated with the previously used efavirenz (neurotoxicity) and nevirapine (hepatotoxicity) therapies. Nonetheless, post-marketing reports of severe ETR-induced skin rash and hypersensitivity reactions have prompted the U.S. FDA to issue a safety alert on ETR. Taking into consideration that ETR usage may increase in the near future, due to the possible use of the drug for coinfection with malaria and HIV, the development of reliable prognostic tools for early risk/benefit estimations is urgent. In the current study, high resolution mass spectrometry-based methodologies were integrated with MS3 experiments for the identification of reactive ETR metabolites/adducts: 1) in vitro incubation of the drug with human and rat liver S9 fractions in the presence of Phase I and II co-factors, including glutathione, as a trapping bionucleophile; and 2) in vivo, using urine samples from HIV-infected patients on ETR therapy. We obtained evidence for multiple bioactivation pathways leading to the formation of covalent adducts with glutathione and N-acetyl-L-cysteine. These results suggest that similar reactions may occur with cysteine residues of proteins, supporting a role for ETR bioactivation in the onset of the toxic effects elicited by the drug. Additionally, ETR metabolites stemming from amine oxidation, with potential toxicological significance, were identified in vitro and in vivo. Also noteworthy is the fact that new metabolic conjugation pathways of glucuronide metabolites were demonstrated for the first time, raising questions about their potential toxicological implications. In conclusion, these results represent not only a contribution towards the elucidation of new metabolic pathways of drugs in general but also an important step towards the elucidation of potentially toxic ETR pathways, whose understanding may be crucial for reliable risk/benefit estimations of ETR-based regimens.
- Rectal ulcer as a complication of Longo’s haemorrhoidopexyPublication . Alberto, S; Oro, I; Sanchez, P; Godinho, A; Garcia, H; Figueiredo, A; Deus, JR