Endothelial AT(1) and AT(2) pathways in aortic responses to angiotensin II after stress and ethanol consumption in rats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Bone stress and strain after use of a miniplate for molar protraction and uprighting: a 3-dimensional finite element analysis

The aim of this study was to use the finite element method to evaluate the distribution of stresses and strains on the local bone tissue adjacent to the miniplate used for anchorage of orthodontic forces. Methods: A 3-dimensional model composed of a hemimandible and teeth was constructed using dental computed tomographic images, in which we assembled a miniplate with fixation screws. The uprighting and mesial movements of the mandibular second molar that was anchored with the miniplate were simulated. The miniplate was loaded with horizontal forces of 2, 5, and 15 N. A moment of 11.77 N.mm was also applied. The stress and strain distributions were analyzed, and their correlations with the bone remodeling criteria and miniplate stability were assessed. Results: When orthodontic loads were applied, peak bone strain remained within the range of bone homeostasis (100-1500 mu m strain) with a balance between bone formation and resorption. The maximum deformation was found to be 1035 mu m strain with a force of 5 N. At a force of 15 N, bone resorption was observed in the region of the screws. Conclusions: We observed more stress concentration around the screws than in the cancellous bone. The levels of stress and strain increased when the force was increased but remained within physiologic levels. The anchorage system of miniplate and screws could withstand the orthodontic forces, which did not affect the stability of the miniplate.

Oxidative stress and nuclear dna damage in hyperglycemic pregnancies

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chlorophyll a fluorescence in Annona emarginata (Schltdl.) H. Rainer plants subjected to water stress and after rehydration

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fatigue surviving, fracture resistance, shear stress and finite element analysis of glass fiber posts with different diameters

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Role of thioredoxin-binding protein 2 in cardiac oxidative stress and energy metabolism of rats supplemented with vitamin D

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Low intensity physical exercise attenuates cardiac remodeling and myocardial oxidative stress and dysfunction in diabetic rats

We evaluated the effects of a low intensity aerobic exercise protocol on cardiac remodeling and myocardial function in diabetic rats. Wistar rats were assigned into four groups: sedentary control (C-Sed), exercised control (C-Ex), sedentary diabetes (DM-Sed), and exercised diabetes (DM-Ex). Diabetes was induced by intraperitoneal injection of streptozotocin. Rats exercised for 9 weeks in treadmill at 11 m/min, 18 min/day. Myocardial function was evaluated in left ventricular (LV) papillary muscles and oxidative stress in LV tissue. Statistical analysis was given by ANOVA or Kruskal-Wallis. Echocardiogram showed diabetic groups with higher LV diastolic diameter-to-body weight ratio and lower posterior wall shortening velocity than controls. Left atrium diameter was lower in DM-Ex than DM-Sed (C-Sed: 5.73 ± 0.49; C-Ex: 5.67 ± 0.53; DM-Sed: 6.41 ± 0.54; DM-Ex: 5.81 ± 0.50 mm; P < 0.05 DM-Sed vs C-Sed and DM-Ex). Papillary muscle function was depressed in DM-Sed compared to C-Sed. Exercise attenuated this change in DM-Ex. Lipid hydroperoxide concentration was higher in DM-Sed than C-Sed and DM-Ex. Catalase and superoxide dismutase activities were lower in diabetics than controls and higher in DM-Ex than DM-Sed. Glutathione peroxidase activity was lower in DM-Sed than C-Sed and DM-Ex. Conclusion. Low intensity exercise attenuates left atrium dilation and myocardial oxidative stress and dysfunction in type 1 diabetic rats.

Oxidative stress and inflammatory response biomarkers in dogs with mammary carcinoma

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The oxidation of p-phenylenediamine, an ingredient used for permanent hair dyeing purposes, leads to the formation of hydroxyl radicals: oxidative stress and DNA damage in human immortalized keratinocytes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Understanding the influence of oxidative stress and physical exercise in the relationship between blood pressure and uric acid

Due to the high incidence and prevalence of hypertension, especially in the elderly population, several studies have been developed to understand the relationship between etiological factors and blood pressure control. It has been demonstrated that hypertensive patients tend to present a status of hyperuricemia. This result suggested that there is a relationship between blood pressure and uric acid concentrations. However there is still a lack of studies that focus on this relationship, and especially how physical exercise could affect the relationship between both of them. Thus, the purpose of this study is to review and discuss the relationship between hypertension and uric acid concentration pointing the oxidative stress as the main factor of this relationship and discuss the physical exercise as the main preventive factor of high uric acid concentrations and oxidative stress. It has been described an increase in oxidative stress during the uric acid pathway because the high production of anions superoxide. This in turn, increases the activation of renin-angiotensin system and decreases nitric oxide bioavailability which will compromise the vasodilatation mechanism. However physical exercises have been associated with improvements in antioxidant capacity and nitric oxide production and bioavailability which will improve the blood pressure control.

Effects of chronic stress and high-fat diet on metabolic and nutritional parameters in Wistar rats

Objective: The aim of this study was assess the role of chronic stress on the metabolic and nutritional profile of rats exposed to a high-fat diet. Materials and methods: Thirty-day-old male Wistar rats (70-100 g) were distributed into four groups: normal-diet (NC), chronic stress (St), high-fat diet (HD), and chronic stress/high-fat diet (HD/St). Stress consisted at immobilization during 15 weeks, 5 times per week, 1h per day; and exposure to the high-fat diet lasted 15 weeks. Nutritional and metabolic parameters were assessed. The level of significance was 5%. Results: The HD group had final body weight, total fat, as well as insulin and leptin increased, and they were insulin resistant. The St and HD/St had arterial hypertension and increased levels of corticosterone. Stress blocked the effects of the high-fat diet. Conclusion: Chronic stress prevented the appearance of obesity. Our results help to clarify the mechanisms involved in metabolic and nutritional dysfunction, and contribute to clinical cases linked to stress and high-fat diet.

Oxidative Stress and Modification of Renal Vascular Permeability Are Associated with Acute Kidney Injury during P. berghei ANKA Infection

Malaria associated-acute kidney injury (AKI) is associated with 45% of mortality in adult patients hospitalized with severe form of the disease. However, the causes that lead to a framework of malaria-associated AKI are still poorly characterized. Some clinical studies speculate that oxidative stress products, a characteristic of Plasmodium infection, as well as proinflammatory response induced by the parasite are involved in its pathophysiology. Therefore, we aimed to investigate the development of malaria-associated AKI during infection by P. berghei ANKA, with special attention to the role played by the inflammatory response and the involvement of oxidative stress. For that, we took advantage of an experimental model of severe malaria that showed significant changes in the renal pathophysiology to investigate the role of malaria infection in the renal microvascular permeability and tissue injury. Therefore, BALB/c mice were infected with P. berghei ANKA. To assess renal function, creatinine, blood urea nitrogen, and ratio of proteinuria and creatininuria were evaluated. The products of oxidative stress, as well as cytokine profile were quantified in plasma and renal tissue. The change of renal microvascular permeability, tissue hypoxia and cellular apoptosis were also evaluated. Parasite infection resulted in renal dysfunction. Furthermore, we observed increased expression of adhesion molecule, proinflammatory cytokines and products of oxidative stress, associated with a decrease mRNA expression of HO-1 in kidney tissue of infected mice. The measurement of lipoprotein oxidizability also showed a significant increase in plasma of infected animals. Together, our findings support the idea that products of oxidative stress, as well as the immune response against the parasite are crucial to changes in kidney architecture and microvascular endothelial permeability of BALB/c mice infected with P. berghei ANKA.

THE SOCIOECONOMIC AND DEMOGRAPHIC CHARACTERIZATION OF CHILDREN AND ADOLESCENTS WHO STUDY AND WORK OUTSIDE THEIR HOME

The objective of this study was to identify the socioeconomic and demographic characteristics of children and adolescents who study and work outside their home. This non-experimental, correlational, cross-sectional study was performed using questionnaires applied to primary education students, enrolled in public schools in Ribeirao Preto (Brazil). Two schools were selected through a draw. Data analysis was performed using Statistical Package for Social Sciences, version 14.0. Of the 133 students who answered the questionnaire, 36 (27.7%) reported working outside their home, 20.6% were between 11 and 13 years of age, and 66.7% were male (p=0.000) and had started working early to help with the family income (p=0.003). The salary they received helped comprise the family income, and it was found that as the family income increased, the need for the youngsters to work was reduced. It was found that many factors contribute to these subjects' early start at work, including family size, structure and poverty.

Exercise training prevents oxidative stress and ubiquitin-proteasome system overactivity and reverse skeletal muscle atrophy in heart failure

Background: Heart failure (HF) is known to lead to skeletal muscle atrophy and dysfunction. However, intracellular mechanisms underlying HF-induced myopathy are not fully understood. We hypothesized that HF would increase oxidative stress and ubiquitin-proteasome system (UPS) activation in skeletal muscle of sympathetic hyperactivity mouse model. We also tested the hypothesis that aerobic exercise training (AET) would reestablish UPS activation in mice and human HF. Methods/Principal Findings: Time-course evaluation of plantaris muscle cross-sectional area, lipid hydroperoxidation, protein carbonylation and chymotrypsin-like proteasome activity was performed in a mouse model of sympathetic hyperactivity-induced HF. At the 7th month of age, HF mice displayed skeletal muscle atrophy, increased oxidative stress and UPS overactivation. Moderate-intensity AET restored lipid hydroperoxides and carbonylated protein levels paralleled by reduced E3 ligases mRNA levels, and reestablished chymotrypsin-like proteasome activity and plantaris trophicity. In human HF (patients randomized to sedentary or moderate-intensity AET protocol), skeletal muscle chymotrypsin-like proteasome activity was also increased and AET restored it to healthy control subjects' levels. Conclusions: Collectively, our data provide evidence that AET effectively counteracts redox imbalance and UPS overactivation, preventing skeletal myopathy and exercise intolerance in sympathetic hyperactivity-induced HF in mice. Of particular interest, AET attenuates skeletal muscle proteasome activity paralleled by improved aerobic capacity in HF patients, which is not achieved by drug treatment itself. Altogether these findings strengthen the clinical relevance of AET in the treatment of HF.

Protein Oxidative Stress and Dyslipidemia in Dialysis Patients

Our aim was to investigate and determine the associations between oxidative stress (OS), dyslipidemia and inflammation in patients treated with continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD) using observational cross-sectional study. Twenty patients in CAPD and 48 in HD for at least 8 weeks and aged =18 years were included in the study. Individuals with malignant or acute inflammatory disease were excluded. A control group of 17 healthy individuals was also recruited. The biochemical parameter evaluations were analyzed using colorimetric kits for albumin, serum glucose, total cholesterol (TC) and lipid fractions. To determine the inflammatory status, CRP, IL-6 and TNF-a were analyzed by automated chemiluminescence kits. Plasma advanced oxidation protein products (AOPP) were determined by spectrophotometry. Mean AOPP levels were significantly higher for the HD group compared to the control, and there was no difference in AOPP concentrations between the control and CAPD groups. Dialysis patients had levels of inflammatory parameters higher than controls, and showed a high prevalence of patients with dyslipidemia, especially in CAPD. In the HD group, AOPP was positively correlated with triglycerides (TG) and inversely associated with HDL. Also the HD group was observed to have negative associations between TNF-a and HDL, LDL and TC. In the CAPD group, CRP was inversely correlated with HDL. Hemodialysis patients had increased protein OS and associations of inflammation and dyslipidemia were also observed in these dialysis groups. A more detailed characterization of the relations between oxidative stress and other more traditional risk factors has therapeutic importance, since cardiovascular diseases are the leading cause of death among dialysis patients.