Oxidative Stress Modulation and Radiosensitizing Effect of Quinoxaline-1,4-Dioxides Derivatives.

BACKGROUND: Quinoxaline-1,4-dioxide (QNX) derivatives are synthetic heterocyclic compounds with multiple biological and pharmacological effects. OBJECTIVE: In this study, we investigated the oxidative status of quinoxaline-1,4-dioxides derivatives in modulating melanoma and glioma cell lines, based on previous results from the research group and their capability to promote cell damage by the production of Reactive Oxygen Species (ROS). METHODS: Using in vitro cell cultures, the influence of 2-amino-3-cyanoquinoxaline-1,4-dioxide (2A3CQNX), 3- methyl-2-quinoxalinecarboxamide-1,4-dioxide (3M2QNXC) and 2-hydroxyphenazine-1,4-dioxide (2HF) was evaluated in metabolic activity, catalase activity, glutathione and 3-nitrotyrosine (3-NT) quantitation by HPLC in malignant melanocytes (B16-F10, MeWo) and brain tumor cells (GL-261 and BC3H1) submitted to radiotherapy treatments (total dose of 6 Gy). RESULTS: 2HF increased the levels of 3-NT in non-irradiated MeWo and glioma cell lines and decreased cell viability in these cell lines with and without irradiation. CONCLUSION: Quinoxaline-1,4-dioxides derivatives modulate the oxidative status in malignant melanocytes and brain tumor cell lines and exhibited a potential radiosensitizer in vitro action on the tested radioresistant cell lines.

Development of a new HPLC-based method for 3-nitrotyrosine quantification in different biological matrices.

BACKGROUND: The nitration of tyrosine residues in proteins is associated with nitrosative stress, resulting in the formation of 3-nitrotyrosine (3-NT).1 3-NT levels in biological samples have been associated with numerous physiological and pathological conditions. Hence several attempts have been made in order to develop methods that accurately quantify 3-NT in these matrices. The aim of this study was to develop a simple, rapid, low-cost and sensitive high-performance liquid chromatography (HPLC)-based 3-NT quantification method. METHODS: All experiments were performed on an Hitachi LaChrom Elite® HPLC system. The method was validated according to International Conference on Harmonisation (ICH) guidelines for serum samples. Additionally, other biological matrices were tested, namely whole blood, urine, B16 F-10 melanoma cell line, growth medium conditioned with the same cell line, bacterial and yeast suspensions. RESULTS: From all the protocols tested, the best results were obtained using 0.5% CH3COOH:MeOH:H2O (15:15:70) as mobile phase, with detection at wavelengths 215, 276 and 356nm, at 25°C, and using a flow rate of 1mLmin-1. By using this protocol, it was possible to obtain a linear calibration curve, limits of detection and quantification in the order of µgL-1, and a short analysis time (<15min per sample). The developed protocol allowed the successful detection and quantification of 3-NT in all biological matrices tested, with detection at 356nm. CONCLUSION: This method, successfully developed and validated for 3-NT quantification, is simple, cheap and fast. These features render this method a suitable option for analysis of a wide range of biological matrices, being a promising useful tool for both research and diagnosis activities.

3-Nitrotyrosine quantification methods: Current concepts and future challenges.

BACKGROUND: Measurement of 3-nitrotyrosine (3-NT) in biological samples can be used as a biomarker of nitrosative stress, since it is very stable and suitable for analysis. Increased 3-NT levels in biological samples have been associated with several physiological and pathological conditions. Different methods have been described for the detection and quantification of this molecule, such as (i) immunological methods; (ii) liquid chromatography, namely high-pressure liquid chromatography (HPLC)-based methods that use ultraviolet-visible (UV/VIS) absorption, electrochemical (ECD) and diode array (DAD) detection, liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS); (iii) gas chromatography, such as gas chromatography-mass spectrometry (GC-MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS). METHODS: A literature review on nitrosative stress, protein nitration, as well as 3-NT quantification methods was carried out. RESULTS: This review covers the different methods for analysis of 3-NT that have been developed during the last years as well as the latest advances in this field. Overall, all methods present positive and negative aspects, although it is clear that chromatography-based methods present good sensitivity and specificity. Regarding this, GC-based methods exhibit the highest sensibility in the quantification of 3-NT, although it requires a prior time consuming derivatization step. Conversely, HPLC does not require such derivatization step, despite being not as accurate as GC. CONCLUSION: It becomes clear that all the methods described during this literature review, although accurate for 3-NT quantification, need to be improved regarding both sensitivity and specificity. Moreover, optimization of the protocols that have been described is clearly needed.

Characterization of human papillomavirus genotypes and HPV-16 physical status in cervical neoplasias of women from northern Portugal.

OBJECTIVE: To determine human papillomavirus (HPV) genotypes and the physical status of HPV-16 DNA among women from northern Portugal with cervical lesions. METHODS: The present retrospective study included samples of cervical exfoliated cells from 88 women (median age 42.0±13.1 years) who attended the Gynecology Service at the Portuguese Institute of Oncology in Porto during 2010. After DNA extraction, HPV genotyping was performed by polymerase chain reaction (PCR) followed by restriction fragment length polymorphism analysis using the MY09/MY11 primers. The physical status of HPV-16 was determined by real-time PCR. RESULTS: Overall, 69.3% of the samples tested positive. The prevalence of HPV infection was 38.5% in normal samples, 57.7% in cervicitis samples, and 87.2% in all cervical lesions including invasive cancers. Sixteen genotypes were detected, the most prevalent ones being HPV-16 (42.9%), HPV-31 (12.2%), and HPV-58 (10.2%); HPV-18 was rare. The overall prevalence of HPV-16 integration was 31.6%. The physical status of HPV-16 did not differ significantly by histology. CONCLUSION: The most frequent genotypes were HPV-16, -31, and -58. Integration of HPV-16 DNA seemed to be an early event in cervical carcinogenesis. Further studies are required to clarify the value of viral integration as a prognostic marker.

Relato de experiência do programa de saúde escolar, nas escolas estaduais de Juiz de Fora / Report on the experience of the health program in state schools of Juiz de Fora

As autoras procuram mostrar como foi iniciado e desenvolvido o Programa de Saúde Escolar, nas Escolas Estaduais, a partir de 1984, em Juiz de Fora. Enfocado a integraçäo da Equipe na promoçäo da Saúde do Escolar, da sua família e da comunidade. Procuram, ainda, influenciar os universitários da área de saúde a participarem dos Programas de Açäo Comunitária, integrando com a Escola, mesmo que os recursos sejam escassos, pois, o resultado, por menor que seja, é extremamente compensador