Papel da melatoninano estresse oxidativo do fígado e sangue de ratos cirróticos

A cirrose é uma hepatopatia crônica e progressiva que constitui um estágio irreversível de disfunção hepática.Este trabalho teve como objetivo avaliar o estresse oxidativo no fígado e sangue de ratos cirróticos e tratados comantioxidante Melatonina (MEL). A cirrose foi induzida através da inalação de tetracloreto de carbono (CCl4)em ratos machos Wistar. Observou-se redução nas provas de integridade hepática nos animais tratados comMEL, aumento da lipoperoxidação nos ratos cirróticos, e redução das mesmas medidas nos animais tratadoscom MEL, em fígado e eritrócitos, diminuição da atividade das enzimas SOD e GPx nos cirróticos e aumentoda SOD nos animais tratados com MEL, aumento dos metabólitos do óxido nítrico e da deposição de colágenonos fígados dos cirróticos e uma diminuição do colágeno nos ratos que receberam MEL. Podemos concluir que aMelatonina pode ser considerada hepatoprotetora e sugerimos que a análise do estresse oxidativo sistêmico podeser um indicador de dano oxidativo.Palavras-chaves : Estresse oxidativo, cirrose hepática, eritrócitos, tetracloreto de carbono e melatonina

Lipoperoxidação no sangue de ratos com síndrome Hepatopulmonar

A sindrome hepatopulmonar (SHP) é caracterizada pela disfunção hepática e a presença de dilataçõesvasculares intrapulmonares, com alterações da difusão de gases, podendo ser demonstrado nomodelo experimental de ligadura de ducto biliar (LDB). O objetivo foi avaliar o potencial antioxidanteda N-acetilcisteína (NAC) no sangue de ratos cirróticos com SHP. Foram utilizados 20 ratos machosWistar, divididos em 4 grupos: Sham operated (SO)+NaCl, LDB+NaCl, SO+NAC e LDB+NAC.Foi avaliado as aminotransferases, gasometria arterial, lipoperoxidação e histologia. Os dados obtidossugerem que a NAC na SHP restaura a função hepática, atenua a lipoperoxidação no sangue e reduza vasodilatação pulmonar.Palavras-chaves: estresse oxidativo; ligadura de ducto biliar; síndrome hepatopulmonar; N-acetilcisteína

Evaluation of systemic inflammation in patients being weaned from mechanical ventilation

OBJECTIVES: The aim of this study was to evaluate systemic inflammatory factors and their relation to success or failure in a spontaneous ventilation test. METHODS: This cross-sectional study included a sample of 54 adult patients. Demographic data and clinical parameters were collected, and blood samples were collected in the first minute of the spontaneous ventilation test to evaluate interleukin (IL)-1b, IL-6, IL-8, and IL-10, tumour necrosis factor alpha (TNFa) and C-reactive protein. RESULTS: Patients who experienced extubation failure presented a lower rapid shallow breathing index than those who passed, and these patients also showed a significant increase in C-reactive protein 48 hours after extubation. We observed, moreover, that each unit increase in inflammatory factors led to a higher risk of spontaneous ventilation test failure, with a risk of 2.27 (1.001 – 4.60, p=0.049) for TNFa, 2.23 (1.06 – 6.54, p=0.037) for IL-6, 2.66 (1.06 – 6.70, p=0.037) for IL-8 and 2.08 (1.01 – 4.31, p=0.04) for IL-10, and the rapid shallow breathing index was correlated with IL-1 (r=-0.51, p=0.04). CONCLUSIONS: C-reactive protein is increased in patients who fail the spontaneous ventilation test, and increased ILs are associated with a greater prevalence of failure in this process; the rapid shallow breathing index may not be effective in patients who present systemic inflammation

Chromosome instability and oxidative stress markers in patients with ataxia telangiectasia and their parents

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The effects of mechanical ventilation on oxidative stress

Objetivo: A ventilação mecânica constitui um dos pilares terapêuticos da unidade de terapia intensiva, entretanto, deve-se avaliar os efeitos deletérios por ela ocasionados, logo objetivamos avaliar o estresse oxidativo de pacientes internados em unidade de terapia intensiva submetidos à ventilação mecânica invasiva. Métodos: Estudo transversal onde foram incluídos 12 pacientes que estavam em ventilação mecânica invasiva. As coletas sanguíneas (3 mL) foram realizadas no primeiro e último dia em que o paciente estava submetido a ventilação mecânica invasiva e utilizou-se o plasma para avaliação das substâncias que reagem ao ácido tiobarbitúrico (TBARS) e os glóbulos vermelhos para dosagem de superóxido dismutase (SOD) e da catalase. Resultados: Os pacientes apresentaram média de idade de 64,8±17,6 anos; volume corrente de 382±44,5 mL e APACHE II de 15±7. Quando comparado o TBARS inicial e ao final da ventilação houve diferença significativa (3,54±0,74 vs. 4,96±1,47; p=0,04). Em relação às enzimas antioxidantes não houve diferença. Observa-se correlação entre as variáveis PaO2 /FiO2 e TBARS (r = 0,4); SOD e PaO2 /FiO2 (r = 0,51) e SOD e APACHE II (r = 0,56). Quanto ao desfecho da internação, 6 pacientes foram a óbito. Conclusão: Pacientes submetidos à ventilação mecânica invasiva podem apresentar alteração do estado redox, marcado pelo aumento no TBARS e redução das enzimas antioxidantes.Objective: Mechanical ventilation is a mainstay of therapy in intensive care units; however, its deleterious effects need to be assessed. Therefore, we aimed to assess oxidative stress in patients admitted to an intensive care unit undergoing invasive mechanical ventilation. Methods: This cross-sectional study included 12 invasive mechanical ventilation patients. Blood samples (3 mL) were collected on the first and last days on invasive mechanical ventilation. Thiobarbituric acidreacting substances (TBARS) were assessed in plasma, and superoxide dismutase (SOD) and catalase (CAT) were assessed in erythrocytes. Results: The mean age was 64.8 ± 17.6 years, the tidal volume (VT) 382 ± 44.5 mL, and the APACHE II score 15 ± 7. When initial and final TBARS were compared, a significant difference was identified (3.54 ± 0.74 vs. 4.96 ± 1.47, p = 0.04). Antioxidant enzymes showed no significant differences. Correlations between PaO2 /FiO2 and TBARS (r = 0.4), SOD and PaO2 /FiO2 (r = 0.51) and APACHE II and SOD (r = 0.56) were identified. Six patients died. Conclusion: Patients undergoing invasive mechanical ventilation can develop redox state changes, showing increased TBARS and reduced antioxidant enzymes

Chromosome Instability and Oxidative Stress Markers in Patients with Ataxia Telangiectasia and Their Parents

Ataxia telangiectasia (AT) is a rare neurodegenerative disorder, inherited in an autosomal recessive manner. Total blood samples were collected from 20 patients with AT, 13 parents of patients, and 17 healthy volunteers. This study aimed at evaluating the frequency of chromosomal breaks in spontaneous cultures, induced by bleomycin and ionizing radiation, and further evaluated the rates of oxidative stress in AT patients and in their parents, compared to a control group. Three cell cultures were performed to each individual: the first culture did not receive induction to chromosomal instability, the second was exposed to bleomycin, and the last culture was exposed to ionizing radiation. To evaluate the rates of oxidative stress, the markers superoxide dismutase (SOD), catalase (CAT), and thiobarbituric acid (TBARS) were utilized. Significant differences were observed between the three kinds of culture treatments (spontaneous, bleomycin, and radiation induced) and the breaks and chromosomal aberrations in the different groups. The oxidative stress showed no significant differences between the markers. This study showed that techniques of chromosomal instability after the induction of ionizing radiation and bleomycin are efficient in the identification of syndrome patients, with the ionizing radiation being the most effective