110 resultados para Oxygen-derived Free Radicals


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Iron and oxidative stress have a regulatory interplay. During the oxidative burst, phagocytic cells produce free radicals such as hypochlorous acid (HOCl). Nevertheless, scarce studies evaluated the effect of either iron deficiency anemia (IDA) or anemia of chronic disease (ACD) on phagocyte function in the elderly. The aim of the present study was to determine the oxidative burst, phagocytosis, and nitric oxide ((aEuro cent)NO) and HOCl, reactive species produced by monocytes and neutrophils in elderly with ACD or IDA. Soluble transferrin receptor, serum ferritin, and soluble transferrin receptor/log ferritin (TfR-F) index determined the iron status. The study was constituted of 39 patients aged over 60 (28 women and 11 men) recruited from the Brazilian Public Health System. Oxidative burst fluorescence intensity per neutrophil in IDA group and HOCl generation in both ACD and IDA groups were found to be lower (p < 0.05). The percentages of neutrophils and monocytes expressing phagocytosis in ACD group were found to be higher (p < 0.05). There was an overproduction of (aEuro cent)NO from monocytes, whereas the fundamental generation of HOCl appeared to be lower. Phagocytosis, oxidative burst, and (aEuro cent)NO and HOCl production are involved in iron metabolism regulation in elderly patients with ACD and IDA.

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Saccharomyces cerevisiae extract (SCE) is used in cosmetics since it can act in oxidative stress and improve skin conditions. This study investigated dermatological effects of cosmetic formulations containing SCE and/or vitamins A, C and E. The formulation studied was supplemented or not (F1: vehicle) with vitamins A, C and E esters (F2) or with SCE (F3) or with the combination of vitamins and SCE (F4). Formulations were patch tested on back skin of volunteers. For efficacy studies, formulations were applied on volunteers and transepidermal water loss (TEWL), skin moisture (SM), skin microrelief (SMR) and free radicals protection were analysed after 3 h, 15 and 30 days of application. Volunteers were also asked about efficacy perception. It was observed that F4 provoked a slight erythema in one volunteer. All formulations enhanced forearm SM. Only F3 and F4 presented long term effects on SMR and showed higher texture values; F3 had the highest brightness values. Our results suggest that vitamins and SCE showed effects in SM and SMR. Only formulations containing SC had long term effects in the improvement of SMR. Thus, these kinds of evaluations are very important in cosmetics development to evaluate the best risk and benefit correlation. (C) 2008 Elsevier Ltd. All rights reserved.

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Amiodarone, a benzofuran derivative. is a very effective antiarrhythmic medication, but has potential to cause side effects. Although its cytotoxicity potential is very well-known, there are few reports about its genotoxicity effects. Since amiodarone has not been investigated in genotoxicity studies, and the spontaneously hypertensive rat (SHR) is a well-characterized model for hypertension, the aim of the present study was to perform cytogenetic analysis on chromosome aberrations in bone marrow cells of SHRs and normotensive Wistar-Kyoto rats (WKYs) that received oral amiodarone treatment for 4 weeks. Amiodarone activity was also monitored using electrocardiograms. The presence of bradycardia in amiodarone-treated rats confirmed that this drug was really active. Metaphase analysis on bone marrow cells showed that there were significant differences in total chromosomal damage and percentage abnormal metaphase between WKY and SHR negative controls. In the SHR negative control, the frequencies of basal chromosomal aberrations and abnormal metaphases were significantly higher (p < 0.05). There were high numbers of chromosomal aberrations in all amiodarone-treated groups, compared with negative controls. In amiodarone-treated groups, the most frequent chromosomal aberration was chromatid breaks. More chromosomal aberrations were found in WKYs that received amiodarone, with a statistically significant difference in comparison with negative controls (p < 0.05). However, in SHR rats there was no significant difference between the amiodarone and negative groups regarding chromosomal damage induction. These results showed that treatment with amiodarone was genotoxic in WKYs, but not in SHRs. Further studies are needed to confirm whether amiodarone is genotoxic or efficient and harmless, among humans undergoing therapy. (c) 2008 Published by Elsevier B.V.

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Introduction: Some studies have made use of the antioxidative capabilities of high doses of vitamins C and E with the aim of neutralizing the noxious effects of free radicals following spinal cord lesion. Objectives: To evaluate the effects of vitamins C and E, separately and together, on the functional performance of rats that were subjected to standardized spinal cord contusion. Materials and methods: Forty male Wistar rats were used, divided into four groups of 10 animals each. Group 3 received vitamin C 100 mg kg(-1) day(-1) intraperitoneally; Group 2 received vitamin E 100 mg kg(-1) day(-1) orally; Group 1 received vitamins C and E, at the same dosages; and Group 4 was the control. The vitamin therapy was administered for 1 month and then the animals were killed. A direct contusional injury was caused and functional evaluation was performed using the Basso, Beattie and Bresnahan rating scale. The rats were evaluated on the second postoperative day and weekly thereafter, until the end of the experiment. Results: The results were evaluated by means of the one-tailed, non-paired and non-parametric Mann-Whitney test, comparing the groups two by two. No significant difference in functional performance was observed between the groups. Conclusion: The use of vitamins C and E in these rats did not improve their neurological performance. However, histopathological examination showed that the inflammatory response was less intense following administration of the combination of vitamins C and E. Spinal Cord (2009) 47, 458-463; doi:10.1038/sc.2008.155; published online 9 December 2008

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In this study, we evaluated the acute effects of central NAC administration on baroreflex in juvenile SHR and Wistar Kyoto (WKY) rats. Male SHR and WKY rats (8 10 weeks old) were implanted with a stainless steel guide cannula into the fourth cerebral ventricle (4th V). The femoral artery and vein were cannulated for mean arterial pressure (MAP) and heart rate (HR) measurement and drug infusion, respectively. After basal MAP and HR recordings, the baroreflex was tested with a pressor dose of phenylephrine (PHE, 8 mu g/kg, bolus) and a depressor dose of sodium nitroprusside (SNP, 50 mu g/kg, bolus). Baroreflex was evaluated before, 5, 15, 30 and 60 minutes after NAC injection into the 4th V. Vehicle treatment did not change baroreflex responses in WKY and SHR. Central NAC slightly but significantly increased basal HR at 15 minutes and significantly reduced PHE-induced increase in MAP 30 and 60 minutes after NAC injection (p < 0.05) in WKY rats. In relation to SHR, NAC decreased HR range 15 and 30 minutes after its administration. In conclusion, acute NAC into the 4th V does not improve baroreflex in juvenile SHR.

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Aim: The present work looked for to evaluate in rats the impact of different diets (high-lipid and high-lipid + high-protein) on liver, verifying the occurrence of oxidative stress and steatosis. Methods: The animals were treated with the respective diets (Group HLS: high-lipid diet with 50% of saturated fat; Group HPLS: high-lipid and high-protein diet with 50% of saturated fat and 40% of protein; Group Control: control diet AIN-93) for 28 days. After this period the animals were sacrificed for hepatic determinations of MDA, reduced GSH, vitamin E, steatosis and glycemia. Results: The results showed higher glycemia in the group HPLS, high concentration of MDA and GSH in the group Control and decreased hepatic vitamin E concentration in the groups that received the high-lipid diets. The hepatic fat was higher in the groups HPLS and HLS in relation to the Group Control, however HPLS presenting high level of fat concentration, showing similar results as the steatosis. Conclusion: the fat increase in the diet promoted increase of the oxidative stress, evidenced by the decrease in the hepatic concentration of vitamin E, showing its antioxidant role against the probable generated free radicals, the ones which possibly exercised a role in the steatosis occurrence.

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The aim of this study was to describe the status of oxidative stress and antioxidant biomarkers and their association with metabolic and body composition components of HIV-lipodystrophy syndrome. In a cross-sectional study of blood samples from HIV-infected men with lipodystrophy syndrome (HIV+LIPO+ = 10), HIV-infected men without lipodystrophy syndrome (HIV+LIPO- = 22), and healthy subjects (control = 12), the following oxidative stress biomarkers were analyzed: total hydroperoxide, thiobarbituric acid reactive substances (TBARS), and advanced oxidation protein products (AOPP). In addition, antioxidant biomarkers, including total glutathione, uric acid, alpha-tocopherol, and metabolic components were tested. Dual-energy x-ray absorciometry (DXA) was used to measure the fat mass. The duration of HIV infection and the duration and type of highly active antiretroviral therapy were similar between the two HIV-infected groups. Higher levels of total hydroperoxide were observed in the HIV+LIPO+ (50 +/- 33 H(2)O(2)/L) group compared to the HIV+LIPO-(19 +/- 13 H(2)O(2)/L) and control (5 +/- 5 H(2)O(2)/L) groups (p < 0.05). Similarly, higher levels of AOPP were observed in the HIV+LIPO+ (326 +/- 173 mu mol/L) group compared to the HIV+LIPO- (105 +/- 92 mu mol/L) and control groups (80 +/- 20 mu mol/L) (p < 0.05). Total hydroperoxide significantly correlated with insulin serum levels in the HIV+LIPO+ (r = 0.47, p < 0.05) and HIV+LIPO- groups (r = 0.29, p < 0.05), while AOPP significantly correlated with insulin serum levels in the HIV+LIPO+ (r = 0.73, p < 0.05) and HIV+LIPO- (r = 0.54, p < 0.05) groups. Therefore, higher lipid and protein oxidation were found in HIV-infected patients with lipodystrophy syndrome, and both were associated with insulin levels.

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This study describes increased sarcolemmal permeability and myofilamentar damage that occur together with lipid peroxidation and protein nitration in the myocardium in severe sepsis induced by cecal ligation and puncture. Male C57BL/6 mice were submitted to moderate and severe septic injury and sham operation. Using light and laser confocal microscopy, diffuse foci of myocytolysis associated with focal disruption of the actin/myosin contractile apparatus could be seen in hearts with severe septic injury. The myocardial expressions of the sarcomeric proteins myosin and actin were downregulated by both severe and moderate injuries. The detection of albumin staining in the cytoplasm of myocytes to evaluate sarcolemmal permeability provided evidence of severe and mild injury of the plasma membrane in hearts with severe and moderate septic injury, respectively. The administration of a superoxide scavenger caused marked reduction of sarcolemmal permeability, indicating the involvement of free radicals in its genesis. On electron microscopy, these changes were seen to correspond to spread blocks of a few myocytes with fragmentation and dissolution of myofibrils, intracellular edema, and, occasionally, rupture of the sarcolemma. In addition, oxidative damage to lipids, using anti-4-hydroxynonenal, an indicator of oxidative stress and disruption of plasma membrane lipids, and to proteins, using antinitrotyrosine, a stable biomarker of peroxynitrite-mediated protein nitration, was demonstrated. These findings make plausible the hypothesis that increased sarcolemmal permeability might be a primary event in myocardial injury in severe sepsis possibly due to oxidative damage to lipids and proteins that could precede phenotypic changes that characterize a septic cardiomyopathy.

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Background and purpose: Calendula officinalis flowers have long been employed time in folk therapy, and more than 35 properties have been attributed to decoctions and tinctures from the flowers. The main uses are as remedies for burns (including sunburns), bruises and cutaneous and internal inflammatory diseases of several origins. The recommended doses are a function both of the type and severity of the condition to be treated and the individual condition of each patient. Therefore, the present study investigated the potential use of Calendula officinalis extract to prevent UV irradiation-induced oxidative stress in skin. Methods: Firstly, the physico-chemical composition of marigold extract(ME) (hydroalcoholic extract)was assessed and the in vitro antioxidant efficacy was determined using different methodologies. Secondly, the cytotoxicity was evaluated in L929 and HepG2 cells with the MTT assay. Finally, the in vivo protective effect of ME against UVB-induced oxidative stress in the skin of hairless mice was evaluated by determining reduced glutathione (GSH) levels and monitoring the secretion/activity of metalloproteinases. Results and conclusions: The polyphenol, flavonoid, rutin and narcissin contents found in ME were 28.6 mg/g, 18.8 mg/g, 1.6 mg/g and 12.2 mg/g, respectively and evaluation of the in vitro antioxidant activity demonstrated a dose-dependent effect of ME against different radicals. Cytoxicity experiments demonstrated that ME was not cytotoxic for L929 and HepG2 cells at concentrations less than or equal to of 15 mg/mL However, concentrations greater than or equal to 30 mg/mL, toxic effects were observed. Finally, oral treatment of hairless mice with 150 and 300 mg/kg of ME maintained GSH levels close to non-irradiated control mice. In addition, this extract affects the activity/secretion of matrix metalloproteinases 2 and 9 (MMP-2 and -9) stimulated by exposure to UVB irradiation. However, additional studies are required to have a complete understanding of the protective effects of ME for skin. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

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Purpose - Chronic ethanol consumption induces lipid peroxidation by increasing free radicals or reducing antioxidants and may increase damage to hepatic DNA. Tannins are polyphenolic metabolites present in various plants and one of their effects is antioxidant activity that reduces lipoperoxidation, as is the case for vitamin E. This paper aims to assess the role of tannic acid and vitamin E in lipid peroxidation and in DNA damage in rats receiving ethanol. Design/methodology/approach - A total of 60 Wistar rats were divided into six groups: control + ethanol (0-24hs), tannic acid + ethanol (0-24 hs), and vitamin E + ethanol (0-24 hs). The animals were sacrificed immediately (0 hour) or 24 hours after a period of four weeks of ethanol administration and the following measurements were made: plasma vitamin E and liver glutathione, thiobarbituric acid resistant substances, and a-tocopherol. The comet test was also applied to hepatocytes. Findings - Ethanol administration led to an increase in DNA damage (148.67 +/- 15.45 versus 172.63 +/- 18.94) during a period of 24 hours which was not detected in the groups receiving tannic acid or vitamin E. Steatosis was lower in the groups receiving tannic acid. Originality/value - The paper highlights that antioxidant role of vitamin E and of tannic acid in biological systems submitted to oxidative stress should be reevaluated, especially regarding the protective role of tannic acid against hepatic steatosis.

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Dietary nitrite and nitrate are important sources of nitric oxide (NO). However, the use of nitrite as an antihypertensive drug may be limited by increased oxidative stress associated with hypertension. We evaluated the antihypertensive effects of sodium nitrite given in drinking water for 4 weeks in two-kidney one-clip (21(1 C) hypertensive rats and the effects induced by nitrite on NO bioavailability and oxidative stress. We found that, even under the increased oxidative stress conditions present in 2K1C hypertension, nitrite reduced systolic blood pressure in a dose-dependent manner. Whereas treatment with nitrite did not significantly change plasma nitrite concentrations in 2K1C rats, it increased plasma nitrate levels significantly. Surprisingly, nitrite treatment exerted antioxidant effects in both hypertensive and sham-normotensive control rats. A series of in vitro experiments was carried out to show that the antioxidant effects induced by nitrite do not involve direct antioxidant effects or xanthine oxidase activity inhibition. Conversely, nitrite decreased vascular NADPH oxidase activity. Taken together, our results show for the first time that nitrite has antihypertensive effects in 2K1C hypertensive rats, which may be due to its antioxidant properties resulting from vascular NADPH oxidase activity inhibition. (C) 2011 Elsevier Inc. All rights reserved.

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Santos, K.B.; Daniel, A.G.T. & Hagiwara, M.K. [Reduced erythrocitary Glutathione and Heinz bodies in cats experimentally infected with the Feline Immunodeficiency Virus.] Glutationa Reduzida Eritrocitaria e Corpusculos de Heinz em gatos infectados experimentalmente pelo Virus da Imunodeficieneia Felina. Revista Brasileira de Medicina Veterinaria, 30(1):26-30, 2008. Centro Universitario Serra dos Orgaos, Rua Comendador Queiroz 52, Apto. 1403, Niteroi, RJ 24230-220, Brasil. E-mail: keilabsantos@)gmail.com The Feline Immunodeficiency Virus (FIV) produces a chronic infection with immunologic system disfunctions in domestic cats developing non-responsive anaemia. The feline immunologic status depression produces free radicals, whose imbalance between production and removal in the organism favour the oxidative injury occurrence. Heinz bodies in large amounts also can evident in vivo oxidative damage. Glutatione, a tripeptide found in the animal cells, is an important protection mechanism against oxidative damages. In this work erythrocyte reduced glutathione (GSH) concentrations for healthy and cats experimentally infected by FIV were determinated in relation to the hemogram and the Heinz bodies presence. All of the animals presents normal values for hemogram and Heinz bodies, however the GSH erythrocyte concentrations in the FIV positive cats were below the normality probably due to an passive depletion to GSH.

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Hyperglycemia induces overproduction of superoxide and it is related to diabetic complications. In this study, we analyzed the antioxidant enzymatic defense and the lipid peroxidation of rat salivary glands in six different periods of diabetic condition. Ninety-six rats were divided into 12 groups: C7/14/21128/45/60 (non-diabetic animals) and D7/14/21/28/45/60 (diabetic animals). Diabetes was induced by streptozotocin and the rats were euthanized after 7, 14, 21, 28, 45, or 60 days. Their parotid (PA) and submandibular (SM) glands were removed soon after the sacrifice and the total protein and malondialdehyde (MDA) concentrations, as well as, the superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities were determined. Twenty-one days after the diabetes induction, the SM glands showed an increase in SOD, CAT, and GPx activities, as well as, MDA concentration. Concerning the PA glands, an increase in the CAT activity and MDA content was observed throughout the observation period. The results suggest that diabetes can cause alterations on the salivary glands and that PA and SM glands react differently when exposed to diabetes condition. However, no impairment of antioxidant system was observed in the group whose diabetic condition had been induced 60 days earlier, herein named 60-day group. Copyright (C) 2010 John Wiley & Sons, Ltd.

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The radiation food processing has been demonstrating great effectiveness in the attack of pathogenic agents, while little compromising nutritional value and sensorial properties of foods. The mate (Ilex paraguariensis), widely consumed product in South America, generally in the form of infusions with hot or cold water, calls of chimarrao or terere, it is cited in literature as one of the best sources phenolic compounds. The antioxidants action of these constituent has been related to the protection of the organism against the free radicals, generated in alive, currently responsible for the sprouting of some degenerative illness as cancer, arteriosclerosis, rheumatic arthritis and cardiovascular clutters among others. The objective of that work was to evaluate the action of the processing for gamma radiation in phenolic compounds of terere beverage in the doses of 0, 3, 5, 7 and 10 kGy. The observed results do not demonstrate significant alterations in phenolic compounds of terere beverage processed by gamma radiation. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.

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This study alms at observing the effect of low-density lipoprotein (LDL) receptor deficiency in cholesterol blood levels, baroreflex sensitivity (BRS), nitric oxide (NO) bioavailability, and oxidative stress. The lack of LDL receptors in mice significantly increased the cholesterol blood levels (179 +/- 35 vs. 109 +/- 13 mg/dL) in the knockout (KO) mice compared to control. There was no difference in basal mean arterial pressure and heart rate between the groups. However, in KO mice the BRS was significantly attenuated and the antioxidant enzyme activities, measured in erythrocytes and heart, were significantly decreased. On the other hand, the oxidative damage measured by chemiluminescence and carbonyls was increased, while total plasma nitrate levels were lower in KO mice, indicating a decrease in NO availability. In conclusion, these results indicate that the lack of LDL receptor increased cholesterol blood levels, induced oxidative stress and decreased BRS. (C) 2008 Elsevier GmbH. All rights reserved.