Effects of cyclooxygenase inhibitors on parasite burden, anemia and oxidative stress in murine Trypanosoma cruzi infection

Prostaglandins are known to be produced by macrophages when challenged with Trypanosoma cruzi, the etiological agent of Chagas` disease. It is not known whether these lipid mediators play a role in oxidative stress in host defenses against this important protozoan parasite. In this study, we demonstrated that inducible cyclooxygenase-mediated prostaglandin production is a key chemical mediator in the control of parasite burden and erythrocyte oxidative stress during T. cruzi infection in C57BL/6 and BALB/c mice, prototype hosts for the study of resistance and susceptibility in murine Chagas` disease. The results suggested the existence of at least two mechanisms of oxidative stress, dependent or independent with regard to the nitric oxide and cyclooxygenase pathway, where one or the other is more evident depending on the mouse strain.

Co-stressors chilling and high light increase photooxidative stress in diuron-treated red alga Kappaphycus alvarezii but with lower involvement of H(2)O(2)

Diuron is one of the most commonly found N-phenylurea herbicides in marine/estuarine waters that promotes toxic effects by inhibiting photosynthesis and affecting the production of reactive oxygen species (ROS) in autotrophs. Since photo- and thermoacclimation are also ROS-mediated processes, this work evaluates a hypothetical additive effect of high light (HL) and chilling (12 degrees C) on 50 nM diuron toxicity to the highly-photosynthetically active apices of the red alga Kappaphycus alvarezii. Additive inhibition of photosynthesis was mainly evidenced by significant decreases of quantum yield of photosystem II and electron transfer rates upon co-stressors exposure to diuron-treated algae. Under extreme 12 degrees C/HL/diuron conditions, unexpected lower correlations between H(2)O(2) concentrations in seawater and radical-sensitive protein thiols were concomitantly measured with the highest indexes of photoinhibition (parameter beta). Altogether, these data support the hypothesis that co-stressors chilling/HL additively inhibit photosynthesis in diuron-exposed K. alvarezii but with less involvement of H(2)O(2) in injury effects than with only chilling or HL. (C) 2010 Elsevier Inc. All rights reserved.

Antioxidant therapy attenuates oxidative stress in the blood of subjects exposed to occupational airborne contamination from coal mining extraction and incineration of hospital residues

Coal mining and incineration of solid residues of health services (SRHS) generate several contaminants that are delivered into the environment, such as heavy metals and dioxins. These xenobiotics can lead to oxidative stress overgeneration in organisms and cause different kinds of pathologies, including cancer. In the present study the concentrations of heavy metals such as lead, copper, iron, manganese and zinc in the urine, as well as several enzymatic and non-enzymatic biomarkers of oxidative stress in the blood (contents of lipoperoxidation = TBARS, protein carbonyls = PC, protein thiols = PT, alpha-tocopherol = AT, reduced glutathione = GSH, and the activities of glutathione S-transferase = GST, glutathione reductase = GR, glutathione peroxidase = GPx, catalase = CAT and superoxide dismutase = SOD), in the blood of six different groups (n = 20 each) of subjects exposed to airborne contamination related to coal mining as well as incineration of solid residues of health services (SRHS) after vitamin E (800 mg/day) and vitamin C (500 mg/day) supplementation during 6 months, which were compared to the situation before the antioxidant intervention (Avila et al., Ecotoxicology 18:1150-1157, 2009; Possamai et al., Ecotoxicology 18:1158-1164, 2009). Except for the decreased manganese contents, heavy metal concentrations were elevated in all groups exposed to both sources of airborne contamination when compared to controls. TBARS and PC concentrations, which were elevated before the antioxidant intervention decreased after the antioxidant supplementation. Similarly, the contents of PC, AT and GSH, which were decreased before the antioxidant intervention, reached values near those found in controls, GPx activity was reestablished in underground miners, and SOD, CAT and GST activities were reestablished in all groups. The results showed that the oxidative stress condition detected previously to the antioxidant supplementation in both directly and indirectly subjects exposed to the airborne contamination from coal dusts and SRHS incineration, was attenuated after the antioxidant intervention.

Monitoring stress tolerance and occurrences of upper respiratory illness in basketball players by means of psychometric tools and salivary biomarkers

The aim of the study was to evaluate the possible relationships between stress tolerance, training load, banal infections and salivary parameters during 4 weeks of regular training in fifteen basketball players. The Daily Analysis of Life Demands for Athletes` questionnaire (sources and symptoms of stress) and the Wisconsin Upper Respiratory Symptom Survey were used on a weekly basis. Salivary cortisol and salivary immunoglobulin A (SIgA) were collected at the beginning (before) and after the study, and measured by enzyme-linked immunosorbent assay (ELISA). Ratings of perceived exertion (training load) were also obtained. The results from ANOVA with repeated measures showed greater training loads, number of upper respiratory tract infection episodes and negative sensation to both symptoms and sources of stress, at week 2 (p < 0.05). Significant increases in cortisol levels and decreases in SIgA secretion rate were noted (before to after). Negative sensations to symptoms of stress at week 4 were inversely and significantly correlated with SIgA secretion rate. A positive and significant relationship between sources and symptoms of stress at week 4 and cortisol levels were verified. In summary, an approach incorporating in conjunction psychometric tools and salivary biomarkers could be an efficient means of monitoring reaction to stress in sport. Copyright (C) 2010 John Wiley & Sons, Ltd.

Ovarian function in cows submitted to acute stress during proestrus

Studies in which ACTH was administrated in heifers after the occurrence of luteolysis showed a delay in the onset of estrus and the estrus duration was shortened. This study evaluated the effect of acute stress by road transportation on estrous behavior and ovulation, monitored by serum progesterone and cortisol concentrations in cows at the periovulatory period, using a crossover design. Eleven crossbred cows, divided into Control and Transport groups had their estrus cycle synchronized with GnRH, an intravaginal progesterone device, and cloprostenol. Thirty hours after withdrawal of the device, the animals of the Transport group were transported for 60 min by truck and those from the Control group remained at pasture. Ovarian ultrasound examination was performed every 12 h from device withdrawal until ovulation in every cow. From the day after removal of the device until ovulation estrous behavior was monitored 24 h a day. Blood samples for serum cortisol and progesterone concentrations were taken at -90, -60, 0, 30, 60 and 180 min in relation to the end of transportation. Transportation during the estrous period induced stress in cows as reflected by changes in serum concentrations of progesterone and cortisol. However, we did not detect impairment in estrus expression, estrus duration or ovulation (P>0.05). (C) 2010 Elsevier B.V. All rights reserved.

Biomarkers of oxidative stress and endothelial dysfunction in glucose intolerance and diabetes mellitus

Objectives: To evaluate biomarkers of endothelial dysfunction and oxidative stress in glucose intolerance (GI) compared to overt diabetes (DM2). Design and methods: 140 volunteers including 96 with DM2, 32 with GI and 12 controls (C) were Studied. NO metabolites, NO synthase inhibitors. thiols and N-acetyl-beta-glucosaminidase (NAGase) activity were analyzed by chemiluminescence, capillary electrophoresis, ELISA and colorimetric assay, respectively. Results: (center dot)NO metabolites were higher in GI (NOx: P=0.03 S-nitrosothiols: p=0.001) and DM2 (p=0.006; p=0.0006) groups in relation to group C, while nitrotyrosine was higher only in the DM2 group in comparison 10 the other groups. NAGase activity was elevated in GI (p=0.003) and DM2 (p=0.0004) groups in relation to group C, as well as, ADMA (p=0.01: p=0.003) and GSSG (p=0.01 p=0.002). Conclusions: (center dot)NO metabolites. (center dot)NO synthase inhibitors. thiols and NAGase are biomarkers Suitable to indicate endothelial dysfunction and oxidative stress in the early stages of impaired response to insulin. (c) 2008 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Involvement of an Alternative Oxidase in Oxidative Stress and Mycelium-to-Yeast Differentiation in Paracoccidioides brasiliensis

Paracoccidioides brasiliensis is a thermodimorphic human pathogenic fungus that causes paracoccidioidomycosis (PCM), which is the most prevalent systemic mycosis in Latin America. Differentiation from the mycelial to the yeast form (M-to-Y) is an essential step for the establishment of PCM. We evaluated the involvement of mitochondria and intracellular oxidative stress in M-to-Y differentiation. M-to-Y transition was delayed by the inhibition of mitochondrial complexes III and IV or alternative oxidase (AOX) and was blocked by the association of AOX with complex III or IV inhibitors. The expression of P. brasiliensis aox (Pbaox) was developmentally regulated through M-to-Y differentiation, wherein the highest levels were achieved in the first 24 h and during the yeast exponential growth phase; Pbaox was upregulated by oxidative stress. Pbaox was cloned, and its heterologous expression conferred cyanide-resistant respiration in Saccharomyces cerevisiae and Escherichia coli and reduced oxidative stress in S. cerevisiae cells. These results reinforce the role of PbAOX in intracellular redox balancing and demonstrate its involvement, as well as that of other components of the mitochondrial respiratory chain complexes, in the early stages of the M-to-Y differentiation of P. brasiliensis.

Effects of Cold Stress, Corticosterone and Catecholamines on Phagocytosis in Mice: Differences between Resting and Activated Macrophages

Objective: We subjected mice to acute cold stress and studied the effect on phagocytosis by peritoneal macrophages mediated by 3 types of phagocytic receptors: Fc gamma, complement receptors 3 (CR3) and mannose and beta-glucan receptors. Methods: Mice were subjected to a cold stress condition (4 C for 4 h), and then peritoneal macrophages were harvested and phagocytosis assays performed in vitro. Results: We found a striking difference between resting and lipopolysaccharide (LPS)-activated macrophages (by intraperitoneal injection of LPS 4 days before the stress experiment): for resting macrophages cold stress caused a decrease in phagocytosis mediated by Fc gamma or mannose receptors, while for activated macrophages we observed an increase in phagocytosis by the 3 types of receptors. These effects were associated with an increase in plasma concentrations of corticosterone and catecholamines following the cold stress. In order to verify whether these hormone changes could account for the observed effects on phagocytosis, we performed in vitro assays by incubating macrophages harvested from nonstressed animals with these hormones for 4 h at 37 degrees C and measuring their phagocytic capacity. The following experiments were done: (a) with resting (nonactivated) macrophages; (b) with macrophages previously activated in vitro by incubation with LPS; (c) with macrophages previously activated in vivo by intraperitoneal injection of mice with LPS, 4 days before harvesting the cells. We found that for resting macrophages, corticosterone decreased phagocytosis mediated by Fc gamma and mannose and beta-glucan receptors, but catecholamines had no effect. For macrophages activated either in vivo or in vitro, catecholamines caused an increase in phagocytosis (excluding mannose receptors) while corticosterone had no effect. Conclusion: The above findings suggest that stress can regulate phagocytosis in different ways, depending on the kind of phagocytic receptor involved, the level of stress hormones and the physiological state of the macrophages. Copyright (C) 2010 S. Karger AG, Basel

Blood and Salivary Oxidative Stress Biomarkers Following an Acute Session of Resistance Exercise in Humans

The aim of the present study was to compare oxidative stress biomarkers determined in blood and saliva before and after acute resistance exercise. 1 week after 1 maximum repetition (1RM) test 11 healthy well-trained males completed a hypertrophy acute session of resistance training including 3 sets of 10 repetitions at 75% of the 1RM, with 90s rest periods between sets. Venous blood and saliva samples were collected before (pre) and 10 min after (post) the resistance training session. A significant (p < 0.05) rise in blood lactate accumulation (pre: 1.6 +/- 0.4 vs. post: 9.5 +/- 2.4) was found post-acute resistance training compared with baseline values. Significant increases (p < 0.05) in TBARS (42%), AOPP (28%), uric acid (27%) and GSH (14%) were detected post-acute resistance training in relation to pre in blood samples. A significant increase (p < 0.05) in uric acid (36%) was found in saliva post-acute resistance training as well as a significant correlation (p < 0.05) between uric acid determined in blood and saliva. Statistical analysis did not reveal any other change in the salivary oxidative stress biomarkers. In conclusion, an acute session of resistance exercise induces oxidative stress in plasma of trained men after acute resistance training, which was not found in saliva samples except for uric acid.

Ethinylestradiol and estradiol have different effects on oxidative stress and nitric oxide synthesis in human endothelial cell cultures

Study objective: To compare the effects of ethinylestradiol (EE) and 17 beta-estradiol (E(2)) on nitric oxide (NO) production and protection against oxidative stress in human endothelial cell cultures. Design: Experimental study. Settings: Research laboratory. Material: Human ECV304 endothelial cell cultures. Intervention(s): The NO synthesis was determined by flow cytometry, and oxidative stress was determined by a cell viability assay, after exposure to hydrogen peroxide (H(2)O(2)) and stimulation of endothelial cells with EE at concentrations similar to those of a contraceptive containing 30 mu g EE. Main Outcome Measure(s): The effects of EE were compared with those of E(2) at concentrations similar to those occurring during the follicular phase. Result(s): Ethinylestradiol did not increase NO synthesis and did not protect cells against oxidative stress. The viability of the cells incubated with E(2) in combination with H(2)O(2) was greater than the viability obtained with H(2)O(2) only or with H(2)O(2) in combination with EE. The cells stimulated with E(2) presented a significant increase in NO production compared with control. Conclusion(s): In contrast to the effects of E(2), EE did not protect human ECV304 endothelial cells against oxidative stress and did not increase their production of NO. (Fertil Steril (R) 2010; 94: 1578-82. (C) 2010 by American Society for Reproductive Medicine.)

Treatment with cannabidiol reverses oxidative stress parameters, cognitive impairment and mortality in rats submitted to sepsis by cecal ligation and puncture

Oxidative stress plays an important role in the development of cognitive impairment in sepsis. Here we assess the effects of acute and extended administration of cannabidiol (CBD) on oxidative stress parameters in peripheral organs and in the brain, cognitive impairment, and mortality in rats submitted to sepsis by cecal ligation and perforation (CLP). To this aim, male Wistar rats underwent either sham operation or CLP. Rats subjected to CLP were treated by intraperitoneal injection with ""basic support"" and CBD (at 2.5, 5, or 10 mg/kg once or daily for 9 days after CLP) or vehicle. Six hours after CLP (early times), the rats were killed and samples from lung, liver, kidney, heart, spleen, and brain (hippocampus, striatum, and cortex) were obtained and assayed for thiobarbituric acid reactive species (TBARS) formation and protein carbonyls. On the 10th day (late times), the rats were submitted to the inhibitory avoidance task. After the test, the animals were killed and samples from lung, liver, kidney, heart, spleen, and brain (hippocampus) were obtained and assayed for TBARS formation and protein carbonyls. The acute and extended administration of CBD at different doses reduced TBARS and carbonyl levels in some organs and had no effects in others, ameliorated cognitive impairment, and significantly reduced mortality in rats submitted to CLP. Our data provide the first experimental demonstration that CBD reduces the consequences of sepsis induced by CLP in rats, by decreasing oxidative stress in peripheral organs and in the brain, improving impaired cognitive function, and decreasing mortality. (C) 2010 Elsevier B.V. All rights reserved.

Alternative body sites for heat stress measurement in milking cows under tropical conditions and their relationship to the thermal discomfort of the animals

This study was conducted to determine the relationship among temperatures measured at different anatomical sites of the animal body and their daily pattern as indicative of the thermal stress in lactating dairy cows under tropical conditions. Environmental dry bulb (DBT) and black globe (BGT) temperatures and relative humidity (RH) were recorded. Rectal temperature (RT), respiratory frequency (RF), body surface (BST), internal base of tail (TT), vulva (VT) and auricular temperatures (AT) were collected, from 37 Black and White Holstein cows at 0700, 1300 and 1800 hours. RT showed a moderately and positive correlations with all body temperatures, ranging from 0.59 with TT to 0.64 with BST. Correlations among AT, VT and TT with RF were very similar (from 0.63 to 0.64) and were greater than those observed for RF with RT (0.55) or with BST (0.54). RF and RT were positively correlated to TT (0.63 and 0.59, respectively), AT (r = 0.63 for both) and VT (r = 0.64 and 0.63, respectively). Positive and very high correlations were observed among AT, VT and TT (from 0.94 to 0.97) indicating good association of temperatures measured in these anatomical sites. Correlations of BST with AT and VT were positive and very similar (0.71 and 0.72, respectively) and lower with TT (0.66). The AT, TT, VT and BST presented similar patterns and follow the variations of DBT through the day. Temperatures measured at different anatomical sites of the animal body have the potential to be used as indicative of the thermal stress in lactating dairy cows.

Peripheral Oxidative Stress Biomarkers in Mild Cognitive Impairment and Alzheimer`s Disease

Oxidative stress has been associated with normal aging and Alzheimer`s disease (AD). However, little is known about oxidative stress in mild cognitive impairment (MCI) patients who present a high risk for developing AD. The aim of this study was to investigate plasma production of the lipid peroxidation marker, malonaldehyde (MDA) and to determine, in erythrocytes, the enzymatic antioxidant activity of catalase, glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione S-transferase (GST) in 33 individuals with MCI, 29 with mild probable AD and 26 healthy aged subjects. GR/GPx activity ratio was calculated to better assess antioxidant defenses. The relationship between oxidative stress and cognitive performance was also evaluated by the Mini Mental State Examination (MMSE). AD patients showed higher MDA levels than both MCI and healthy elderly subjects. MCI subjects also exhibited higher MDA levels compared to controls. Catalase and GPx activity were similar in MCI and healthy individuals but higher in AD. GR activity was lower in MCI and AD patients than in healthy aged subjects. Additionally, GR/GPx ratio was higher in healthy aged subjects, intermediate in MCI and lower in AD patients. No differences in GST activity were detected among the groups. MMSE was negatively associated with MDA levels (r = -0.31, p = 0.028) and positively correlated with GR/GPx ratio in AD patients (r = 0.68, p < 0.001). MDA levels were also negatively correlated to GR/GPx ratio (r = -0.31, p = 0.029) in the AD group. These results suggest that high lipid peroxidation and decreased antioxidant defenses may be present early in cognitive disorders.

Effects of aerobic exercise on the blood pressure, oxidative stress and eNOS gene polymorphism in pre-hypertensive older people

The polymorphisms of endothelial nitric oxide synthase (eNOS) are associated with reduced eNOS activity. Aerobic exercise training (AEX) may influence resting nitric oxide (NO) production, oxidative stress and blood pressure. The purpose of this study was to investigate the effect of AEX on the relationship among blood pressure, eNOS gene polymorphism and oxidative stress in pre-hypertensive older people. 118 pre-hypertensive subjects (59 +/- A 6 years) had blood samples collected after a 12 h overnight fast for assessing plasma NO metabolites (NOx) assays, thiobarbituric acid reactive substances (T-BARS) and superoxide dismutase activity (ecSOD). eNOS polymorphism (T-786C and G-894T) was done by standard PCR methods. All people were divided according to the genotype results (G1: TT/GG, G2: TT/GT + TT, G3: TC + CC/GG, G4: TC + CC/GT + TT). All parameters were measured before and after 6 months of AEX (70% of VO(2 max)). At baseline, no difference was found in systolic and diastolic blood pressure, ecSOD and T-BARS activity. Plasma NOx levels were significantly different between G1 (19 +/- A 1 mu M) and G4 (14.2 +/- A 0.6 mu M) and between G2 (20.1 +/- A 1.7 mu M) and G4 (14.2 +/- A 0.6 mu M). Therefore, reduced NOx concentration in G4 group occurred only when the polymorphisms were associated, suggesting that these results are more related to genetic factors than NO-scavenging effect. After AEX, the G4 increased NOx values (17.2 +/- A 1.2 mu M) and decreased blood pressure. G1, G3 and G4 decreased T-BARS levels. These results suggest the AEX can modulate the NOx concentration, eNOS activity and the relationship among eNOS gene polymorphism, oxidative stress and blood pressure especially in C (T-786C) and T (G-894T) allele carriers.

Occupational airborne contamination in South Brazil: 2. Oxidative stress detected in the blood of workers of incineration of hospital residues

One of the most useful methods for elimination of solid residues of health services (SRHS) is incineration. However, it also provokes the emission of several hazardous air pollutants such as heavy metals, furans and dioxins, which produce reactive oxygen species and oxidative stress. The present study, which is parallel to an accompanied paper (Avila Jr. et al., this issue), investigated several enzymatic and non-enzymatic biomarkers of oxidative stress in the blood (contents of vitamin E, lipoperoxidation = TBARS, reduced glutathione = GSH, oxidized glutathione = GSSG, and activities of glutathione S-transferase = GST, glutathione reductase = GR, glutathione peroxidase = GPx, catalase = CAT and superoxide dismutase = SOD), in three different groups (n = 20 each) exposed to airborne contamination associated with incineration of SRHS: workers directly (ca. 100 m from the incinerator) and indirectly exposed (residents living ca. 5 km the incineration site), and controls (non-exposed subjects). TBARS and GSSG levels were increased whilst GSH, TG and alpha-tocopherol contents were decreased in workers and residents compared to controls. Increased GST and CAT activities and decreased GPx activities were detected in exposed subjects compared to controls, while GR did not show any difference among the groups. In conclusion, subjects directly or indirectly exposed to SRHS are facing an oxidative insult and health risk regarding fly ashes contamination from SRHS incineration.