542 research outputs found
VOCAÇÃO POLÍTICA DA IGREJA EM TEMPOS SOMBRIOS: DENÚNCIA DE DIETRICH BONHOEFFER AO MESSIANISMO POLÍTICO
O artigo apresenta, posto que em síntese, a importância da política na vida social e, ato contínuo, o conceito de messianismo na política. Isto posto, a partir da compreensão de igreja na teologia de Dietrich Bonhoeffer o artigo traz subsídios para uma crítica ao messianismo político atualmente em voga no Brasil, da parte de alguns setores da igreja evangélica.
Study of ventilation with different inspired oxygen concentration on lung ischaemia-reperfusion injury in rats
PURPOSE: To evaluate the FiO2 effect at 0,21, 0,40 and 1,00 on the lung ischaemia-reperfusion injury. METHODS: Forty Wistar rats were randomly allocated in 4 groups. The group I was the control one, and in groups II, III, IV rats were ventilated during the ischaemia-reperfusion at 0,21, 0,40 and 1.00 FiO2 respectively. The ischaemia time was 30 minutes and the reperfusion time was 10 minutes. The model used was normothermic ischaemia-reperfusion, in situ. As assessment parameters, the systemic average arterial pressure (PAM), the oxygen arterial partial pressure/ inspired oxygen fraction relation (PO2/FiO2), the level of reduced glutathione (GSH) and barbituric acid substances reactive measure (TBARS) in the lung tissue and the lung wet/dry weight ratio were used. RESULTS: The results showed that the ventilation with FiO2 at 0,21, when compared with the ventilation at 0,40 and 1,00 FiO2 during the ischaemia-reperfusion period, presented lower PAM, better PO2/FiO2 relation, higher values in the reduced glutathione measures, lower production of the TBARS and lower formation of lung edema. CONCLUSION: The ventilation with low FiO2 (0.21) showed better results when compared to those performed with higher FiO2 (0,40 and 1,00) on the lung ischaemia-reperfusion injury.OBJETIVO: Estudar o efeito das frações inspiradas de oxigênio (FiO2) a 0,21, 0,40 e 1,00 na isquemia-reperfusão pulmonar. MÉTODOS: Foram utilizados 40 ratos Wistar, distribuídos aleatoriamente em quatro grupos. O grupo I foi o controle e, nos grupos II, III e IV, os animais foram ventilados durante a isquemia-reperfusão com FiO2 a 0,21, 0,40 e 1,00 respectivamente. O modelo utilizado foi de isquemia-reperfusão normotérmica, in situ. O tempo de isquemia foi de 30 minutos e o de reperfusão, de 10 minutos. Como parâmetros de avaliação, utilizou-se a pressão arterial média sistêmica (PAM), a relação entre a pressão parcial de oxigênio e a fração inspirada de oxigênio (PO2/FiO2), a dosagem da glutationa reduzida (GSH) e das substâncias reativas ao ácido tiobarbitúrico (TBARS) no tecido pulmonar e a relação entre o peso pulmonar úmido e o peso pulmonar seco. RESULTADOS: Os resultados mostraram que a ventilação com FiO2 a 0,21, quando comparada à ventilação com FiO2 a 0,40 e 1,00, durante o período de isquemia-reperfusão, apresentou menor diminuição da PAM, melhor relação PO2/FiO2, maior valor na medida da GSH, menor produção das TBARS e menor formação de edema pulmonar. CONCLUSÃO: A ventilação com baixa FiO2 (0,21) mostrou melhores resultados quando comparada àquelas realizadas com FiO2 mais elevadas (0,40 e 1,00) na isquemia-reperfusão pulmonar.Secretaria Estadual de Saúde de Santa CatarinaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUniversidade Federal de Santa Catarina Escola Paulista de Medicina Departamento de CirurgiaUniversidade Federal de Santa Catarina Departamento de Clínica CirúrgicaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de CirurgiaUNIFESP, EPMUniversidade Federal de Santa Catarina Escola Paulista de Medicina Depto. de CirurgiaUNIFESP, EPM, Depto. de CirurgiaSciEL
Editorial: Oncogenic PI3KT/Akt/mTOR pathway alterations, ROS homeostasis, targeted cancer therapy and drug resistance
Potent hepatoprotective effect in CCl4-induced hepatic injury in mice of phloroacetophenone from Myrcia multiflora
Background: This study investigated the hepatoprotective effect and antioxidant properties of phloroacetophenone (2′,4′,6′-trihydroxyacetophenone – THA), an acetophenone derived from the plant Myrcia multiflora.Material & Method: The free radical scavenging activity in vitro and induction of oxidative hepatic damage by carbon tetrachloride (CCl4) (0.5 ml/kg, i.p.) were tested in male Swiss mice (25±5 g). Results: This compound exhibited in vitro antioxidant effects on FeCl2–ascorbate-induced lipid peroxidation (LPO) in mouse liver homogenate, scavenging hydroxyl and superoxide radicals, and 2,2-diphenyl-1-picrylhydrazyl. The in vivo assays showed that THA significantly (p<0.01) prevented the increases of hepatic LPO as measured by the levels of thiobarbituric acid-reactive substances, mitochondrial swelling. It also protected hepatocytes against protein carbonylation and oxidative DNA damage. Consistent with these observations, THA pre-treatment normalized the activities of antioxidant enzymes, such as catalase, glutathione peroxidase, and superoxide dismutase, and increased the levels of reduced glutathione (GSH) in CCl4-treated mice. In addition, THA treatment significantly prevented the elevation of serum enzymatic activities of alanine amino transferase, aspartate amino transferase, and lactate dehydrogenase, as well as histological alterations induced by CCl4. Silymarin (SIL) (24 mg/kg), a known hepatoprotective drug used for comparison, led to a significant decrease (p<0.01) in activities of theses enzymes in way very similar to that observed in pre-treatment with THA. Conclusion: These results suggest that the protective effects are due to reduction of oxidative damage induced by CCl4 resulting from the antioxidant properties of THA
Seasonal Variations of the Activity of Antioxidant Defense Enzymes in the Red Mullet (Mullus barbatus l.) from the Adriatic Sea
This study investigated seasonal variations of antioxidant defense enzyme activities: total, manganese, copper zinc containing superoxide dismutase (Tot SOD, Mn SOD, CuZn SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and biotransformation phase II enzyme glutathione-S-transferase (GST) activity in the liver and white muscle of red mullet (Mullus barbatus). The investigations were performed in winter and spring at two localities: Near Bar (NB) and Estuary of the River Bojana (EB) in the Southern Adriatic Sea. At both sites, Mn SOD, GSH-Px, GR and GST activities decreased in the liver in spring. In the white muscle, activities of Mn SOD, GSH-Px, GR and GST in NB decreased in spring. GR decreased in spring in EB, while CAT activity was higher in spring at both sites. The results of Principal Component Analysis (PCA) based on correlations indicated a clear separation of various sampling periods for both investigated tissues and a marked difference between two seasons. Our study is the first report on antioxidant defense enzyme activities in the red mullet in the Southern Adriatic Sea. It indicates that seasonal variations of antioxidant defense enzyme activities should be used in further biomonitoring studies in fish species
Implications of dealing with airborne substances and reactive oxygen species: what mammalian lungs, animals and plants have to say?
A gas-exchange structure interacts with the environment and is constantly challenged by contaminants that may elicit defense responses, thus compromising its primary function. It is also exposed to high concentrations of O2 that can generate reactive oxygen species (ROS). Revisiting the lung of mammals, an integrative picture emerges, indicating that this bronchi-alveolar structure deals with inflammation in a special way, which minimizes compromising the gas-exchange role. Depending on the challenge, pro-inflammatory or antiinflammatory responses are elicited by conserved molecules, such as surfactant proteins A and D. An even broader picture points to the participation of airway sensors, responsive to inflammatory mediators, in a loop linking the immunological and nervous systems and expanding the role played by respiratory organs in functions other than gas-exchange. A byproduct of exposure to high concentration of O2 is the formation of superoxide (), hydrogen peroxide (H2O2), hydroxyl radical (HO•), and other ROS, which are known to be toxic to different types of cells, including the lung epithelium. A balance between antioxidants and oxidants exists; in pulmonary epithelial cells high intracellular and extracellular levels of antioxidants are found. Antioxidant adaptations related to plant and animal life-styles involve a broad range of overlapping strategies based on well-conserved molecules. Glutathione (GSH) is an abundant and ubiquitous thiol-tripeptide antioxidant, also present in lungs, whose role in providing information on the intracellular redox state of animals and plants is well established. In these organisms, GSH influences gene expression associated with stress, maximizing defense responses. Several enzymatic antioxidants, such as glutathione peroxidase (GPx), glutathione reductase, glutathione S-transferase, and glucose 6-phosphate dehydrogenase participate in the redox system; in animals that are stress-tolerant GPx is a key element against oxidative assaults. Most importantly, alternative roles of ROS as signaling molecules have been found in all plants and animals. For example, alveolar macrophages produce that act as second messengers, in addition to having a bactericidal role. The nonradical ROS H2O2 signals inflammation in mammalian lungs, apoptosis in different animal tissues, and is also involved in stomatal closure, root development, gene expression, and defense responses of plants. Antioxidant adaptations in some water-breathing animals involve the excretion of H2O2 by diffusion through gas-exchange structures. The fine balance among a multitude of factors and cells makes the difference between damage and protection in animals and plants. Knowledge about the mechanisms and consequences of these molecular interactions is now starting to be integrated
Selenium inclusion decreases oxidative stress indicators and muscle injuries in sea bass larvae fed high-DHA microdiets
The objective of the present study was to determine the effect of Se inclusion in high-DHA and vitamin E microdiets (5 g DHA/100 g dry weight and 300 mg vitamin E/100 g dry weight; 5 g DHA/100 g dry weight and 300 mg vitamin E/100 g dry weight supplemented with Se) in comparison with a control diet (1 g DHA/100 g dry weight and 150 mg vitamin E/100 g dry weight) on sea bass larval growth, survival, biochemical composition, malonaldehyde (MDA) content, muscle morphology and antioxidant enzymes (AOE), insulin-like growth factors (IGF) and myosin expression. For a given DHA and vitamin E dietary content, Se inclusion favoured larval total length and specific growth rate, and reduced the incidence of muscular lesions, MDA contents and AOE gene expression. In contrast, IGF gene expression was elevated in the 5/300 larvae, suggesting an increased muscle mitogenesis that was corroborated by the increase in mRNA copies of myosin heavy chain. The results of the present study denoted the beneficial effect of Se not only in preventing oxidative stress, as a glutathione peroxidase cofactor, but probably due to other as yet unknown physiological functions
Uncertainty evaluation associated with versatile automated gauging influenced by process variations through design of experiments approach
Recent advances in versatile automated gauging have enabled accurate geometric tolerance assessment on the shop floor. This paper is concerned with the uncertainty evaluation associated with comparative coordinate measurement using the design of experiments (DOE) approach. It employs the Renishaw Equator which is a software-driven comparative gauge based on the traditional comparison of production parts to a reference master part. The fixturing requirement of each production part to the master part is approximately ±1 mm for a comparison process with an uncertainty of ±2 μm. Therefore, a number of experimental designs are applied with the main focus on the influence of part misalignment from rotation between master and measure coordinate frames on the comparator measurement uncertainty. Other factors considered include measurement mode mainly in scanning and touch-trigger probing (TTP) and alignment procedure used to establish the coordinate reference frame (CRF) with respect to the number of contact points used for each geometric feature measured. The measurement uncertainty analysis of the comparator technique used by the Equator gauge commences with a simple measurement task using a gauge block to evaluate the three-dimensional (3D) uncertainty of length comparative coordinate measurement influenced by an offset by tilt in one direction (two-dimensional angular misalignment). Then, a specific manufactured measurement object is employed so that the comparator measurement uncertainty can be assessed for numerous measurement tasks within a satisfactory range of the working volume of the versatile gauge. Furthermore, in the second case study, different types of part misalignment including both 2D and 3D angular misalignments are applied. The time required for managing the re-mastering process is also examined. A task specific uncertainty evaluation is completed using DOE. Also, investigating the effects of process variations that might be experienced by such a device in workshop environments. It is shown that the comparator measurement uncertainties obtained by all the experiments agree with system features under specified conditions. It is also demonstrated that when the specified conditions are exceeded, the comparator measurement uncertainty is associated with the measurement task, the measurement strategy used, the feature size, and the magnitude and direction of offset angles in relation to the reference axes of the machine. In particular, departures from the specified part fixturing requirement of Equator have a more significant effect on the uncertainty of length measurement in comparator mode and a less significant effect on the diameter measurement uncertainty for the specific Equator and test conditions
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