RESUMEN
Tryptophan (TRP) is essential for many physiological processes, and its metabolism changes in some diseases such as infection and cancer. The most studied aspects of TRP metabolism are the kynurenine and serotonin pathways. A minor metabolic route, tryptamine and N,N-dimethyltryptamine (DMT) biosynthesis, has received far less attention, probably because of the very low amounts of these compounds detected only in some tissues, which has led them to be collectively considered as trace amines. In a previous study, we showed a metabolic interrelationship for TRP in melanoma cell lines. Here, we identified DMT and N,N-dimethyl-N-formyl-kynuramine (DMFK) in the supernatant of cultured SK-Mel-147 cells. Furthermore, when we added DMT to the cell culture, we found hydroxy-DMT (OH-DMT) and indole acetic acid (IAA) in the cell supernatant at 24 h. We found that SK-Mel-147 cells expressed mRNA for myeloperoxidase (MPO) and also had peroxidase activity. We further found that DMT oxidation was catalyzed by peroxidases. DMT oxidation by horseradish peroxidase, H2O2 and MPO from PMA-activated neutrophils produced DMFK, N,N-dimethyl-kynuramine (DMK) and OH-DMT. Oxidation of DMT by peroxidases apparently uses the common peroxidase cycle involving the native enzyme, compound I and compound II. In conclusion, this study describes a possible alternative metabolic pathway for DMT involving peroxidases that has not previously been described in humans and identifies DMT and metabolites in a melanoma cell line. The extension of these findings to other cell types and the biological effects of DMT and its metabolites on cell proliferation and function are key questions for future studies.
Asunto(s)
N,N-Dimetiltriptamina/biosíntesis , Peroxidasas/metabolismo , Línea Celular Tumoral , Peroxidasa de Rábano Silvestre/química , Humanos , Peróxido de Hidrógeno/química , Melanoma , N,N-Dimetiltriptamina/química , Activación Neutrófila , Neutrófilos/metabolismo , Peroxidasa/metabolismoRESUMEN
OBJECTIVE: The goal of this study was to monitor imatinib mesylate therapeutically in the Tumor Biology Laboratory, Department of Hematology and Hemotherapy, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (USP). A simple and sensitive method to quantify imatinib and its metabolite (CGP74588) in human serum was developed and fully validated in order to monitor treatment compliance. METHODS: The method used to quantify these compounds in serum included protein precipitation extraction followed by instrumental analysis using high performance liquid chromatography coupled with mass spectrometry. The method was validated for several parameters, including selectivity, precision, accuracy, recovery and linearity. RESULTS: The parameters evaluated during the validation stage exhibited satisfactory results based on the Food and Drug Administration and the Brazilian Health Surveillance Agency (ANVISA) guidelines for validating bioanalytical methods. These parameters also showed a linear correlation greater than 0.99 for the concentration range between 0.500 µg/mL and 10.0 µg/mL and a total analysis time of 13 minutes per sample. This study includes results (imatinib serum concentrations) for 308 samples from patients being treated with imatinib mesylate. CONCLUSION: The method developed in this study was successfully validated and is being efficiently used to measure imatinib concentrations in samples from chronic myeloid leukemia patients to check treatment compliance. The imatinib serum levels of patients achieving a major molecular response were significantly higher than those of patients who did not achieve this result. These results are thus consistent with published reports concerning other populations.
RESUMEN
OBJECTIVE: The goal of this study was to monitor imatinib mesylate therapeutically in the Tumor Biology Laboratory, Department of Hematology and Hemotherapy, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (USP). A simple and sensitive method to quantify imatinib and its metabolite (CGP74588) in human serum was developed and fully validated in order to monitor treatment compliance. METHODS: The method used to quantify these compounds in serum included protein precipitation extraction followed by instrumental analysis using high performance liquid chromatography coupled with mass spectrometry. The method was validated for several parameters, including selectivity, precision, accuracy, recovery and linearity. RESULTS: The parameters evaluated during the validation stage exhibited satisfactory results based on the Food and Drug Administration and the Brazilian Health Surveillance Agency (ANVISA) guidelines for validating bioanalytical methods. These parameters also showed a linear correlation greater than 0.99 for the concentration range between 0.500 µg/mL and 10.0 µg/mL and a total analysis time of 13 minutes per sample. This study includes results (imatinib serum concentrations) for 308 samples from patients being treated with imatinib mesylate. CONCLUSION: The method developed in this study was successfully validated and is being efficiently used to measure imatinib concentrations in samples from chronic myeloid leukemia patients to check treatment compliance. The imatinib serum levels of patients achieving a major molecular response were significantly higher than those of patients who did not achieve this result. These results are thus consistent with published reports concerning other populations.
Asunto(s)
Humanos , Antineoplásicos/administración & dosificación , Cromatografía , Monitoreo de Drogas , Leucemia Mielógena Crónica BCR-ABL Positiva , Espectrometría de Masas , Pirimidinas/administración & dosificaciónRESUMEN
Os efeitos tóxicos mais imediatos de uma intoxicação por organofosforados ou carbamatos devem-se à inibição das colinesterases (ChES). Contudo, as faixas de variação de atividade tanto interindividual como intraindividual das ChEs são muito largas o que dificulta a interpretação dos resultados da atividade das ChEs de trabalhadores expostos a organofosforados e carbamatos. Utilizando-se o método de Nabb & Whitfield (1967) para analisar sangue de 48 trabalhadores, os resultados mostraram que a colinesterase eritrocitária (ChE-Er) variou de 10,1 a 19,7 μmol/min/mL e a colinesterase plasmática (ChE-PI) de 2,2 a 6,9 μmol/min/ML. Apesar de grande variação interindividual, com a linha de base pré-exposição que utiliza a variação intraindividual foi possível correlacionar sintomas de intoxicação leve a exposição ocupacional ao carbamato, com queda na atividade da ChE-Er menor que 30% da atividade da linha de base pré-exposição...