Studies on the effect of Polycyclic Aromatic Hydrocarbons in the life and activity of Perna spp

In the present study an endeavour has been made to analyse the acute toxicity of WAFs of Bombay High crude and Light Diesel oil on commercially important bivalve species Perna viridis and Perna indica by static bioassay methods. The toxic effects of chemicals in the WAF on the organisms ; their tissues and eventually on rate functions have been elucidated. Marine oil pollution not only affects productivity and quality of marine organisms but also eventually affects the health of human population due to a possible health risk by way of consumption of oil contaminated seafood

Effects of pancreas transplantation on oxidative stress in pulmonary tissue from alloxan-induced diabetic rats

Purpose. There is considerable evidence that cellular oxidative stress caused by hyperglycemia plays an important role in the genesis and evolution of chronic diabetic lesions. In this study, we determined the effectiveness of pancreas transplantation (PT) in preventing the imbalance caused by excessive production of reactive oxygen species over antioxidant defenses in lungs of rats rendered diabetic by alloxan injection.Methods. Sixty inbred male Lewis rats, weighing 250-280 g, were randomly assigned to 3 experimental groups: NC, 20 nondiabetic control rats; DC, 20 untreated diabetic control rats; and PT, 20 diabetic rats that received syngeneic PT from normal donor Lewis rats. Each group was further divided into 2 subgroups of 10 rats each which were killed after 4 and 12 weeks of follow-up. Plasma glucose, glycosylated hemoglobin, and insulin levels were determined in all rats. Lipid hydroperoxide (LPO) concentrations and enzyme activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were measured in the pulmonary tissue of all rats.Results. The DC rats showed elevated blood glucose and glycosylated hemoglobin levels, with insulin blood levels significantly lower than the NC rats (P < .001). They also showed significantly increased LPO concentrations in the lungs (P < .01) after 4 and 12 weeks of follow-up. In contrast, SOD, CAT, and GSH-Px antioxidant activities were significantly reduced in these periods (P < .01) 12 weeks after diabetes induction. Successful PT corrected all clinical and metabolic changes in the diabetic rats, with sustained normoglycemia throughout the study. Excessive lung LPO production and low SOD, CAT, and GSH-Px antioxidant activities were already back to normal 4 weeks after PT.Conclusion. PT can control oxidative stress in pulmonary tissue of diabetic rats. It may be the basis for preventing chronic diabetic lesions in lungs.

The influence of hydroxyurea on oxidative stress in sickle cell anemia

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

Influence of N-acetylcysteine on oxidative stress in slow-twitch soleus muscle of heart failure rats

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

The influence of hydroxyurea on oxidative stress in sickle cell anemia

OBJECTIVE: The oxidative stress in 20 sickle cell anemia patients taking hydroxyurea and 13 sickle cell anemia patients who did not take hydroxyurea was compared with a control group of 96 individuals without any hemoglobinopathy. METHODS: Oxidative stress was assessed by thiobarbituric acid reactive species production, the Trolox-equivalent antioxidant capacity and plasma glutathione levels. RESULTS: Thiobarbituric acid reactive species values were higher in patients without specific medication, followed by patients taking hydroxyurea and the Control Group (p < 0.0001). The antioxidant capacity was higher in patients taking hydroxyurea and lower in the Control Group (p = 0.0002 for Trolox-equivalent antioxidant capacity and p < 0.0292 for plasma glutathione). Thiobarbituric acid reactive species levels were correlated with higher hemoglobin S levels (r = 0.55; p = 0.0040) and lower hemoglobin F concentrations(r = -0.52; p = 0.0067). On the other hand, plasma glutathione levels were negatively correlated with hemoglobin S levels (r = -0.49; p = 0.0111) and positively associated with hemoglobin F values (r = 0.56; p = 0.0031). CONCLUSION: Sickle cell anemia patients have high oxidative stress and, conversely, increased antioxidant activity. The increase in hemoglobin F levels provided by hydroxyurea and its antioxidant action may explain the reduction in lipid peroxidation and increased antioxidant defenses in these individuals.

Studies on Oxidative Couplings in H-Phosphonate Chemistry

In this thesis oxidative coupling of H-phosphonate and H phosphonothioate diesters with different alcohols and amines are presented. Since the reactions with alcohols previously have been particularly unfavourable due to competing side reactions, a modified protocol leading to high coupling yields of structurally diverse hydroxylic components was developed. The phosphorylation reaction was studied using 31P NMR spectroscopy and for the first time the previously only postulated reactive intermediate involved in these reactions was observed. The use of iodine in combination with a bulky chlorosilane in pyridine was found to have a profound effect on both the suppression of side reactions and the rate of the oxidative couplings, and led to a clean formation of phosphorylated products in high yields. This synthetic protocol was then extended to include coupling reactions with bis-functional reagents containing hexamethylene linkers to provide handles for derivatisations of oligonucleotides. A synthetic protocol consisting of the stereospecific oxidative coupling of amines with H-phosphonate diesters to produce phosphoroamidates was designed in such a way that it permitted control of the stereochemical outcome of the reactions. Based on a silylation-mediated reaction utilising phenyl H phosphonothioate monoester as a thiophosphonyl transferring agent, a method was developed and used for the preparation of H-phosphonothioate building blocks for the synthesis of DNA analogues.

A systematic review of observational studies on oxidative/nitrosative stress involvement in dengue pathogenesis

Objective: Our objective was to systematically review the published observational research related to the role of oxidative-nitrosative stress in pathogenesis of dengue. Methods: We searched electronic databases (PubMed, EMBASE, The COCHRANE library, ScienceDirect, Scopus, SciELO, LILACS via Virtual Health Library, Google Scholar) using the term: dengue, dengue virus, severe dengue, oxidative stress, nitrosative stress, antioxidants, oxidants, free radicals, oxidized lipid products, lipid peroxides, nitric oxide, and nitric oxide synthase. Articles were selected for review by title and abstract excluding letter, review, in vivo and in vitro studies, and duplicates studies. Selected articles were reviewed for study design, original purposes, sample size, main outcomes, methods, and oxidative-nitrosative stress markers values. Results: In total, 4,331 non-duplicates articles were identified from electronic databases searches, of which 16 were eligible for full text searching. Data from the observational studies originate from Asian countries (50%; 8/16), South American countries (31.2%; 5/16), and Central America and the Caribbean countries (18.8%; 3/16). Casecontrol study was the type of design most common in researches reviewed. The 1997 World Health Organization (WHO) dengue case classification criteria were used in all studies included in this review. Conclusions: Based on published data found in peer-reviewed literature, oxidative and nitrosative stress are demonstrated by changes in plasma levels of nitric oxide, antioxidants, lipid peroxidation and protein oxidation markers in patients with dengue infection. Additionally, elevated serum protein carbonyls and malondialdehyde levels appear to be associated with dengue disease severity.

Resveratrol toxicity: Effects on risk factors for atherosclerosis and hepatic oxidative stress in standard and high-fat diets

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Impact of weight loss on oxidative stress and inflammatory cytokines in obese type 2 diabetic patients.

Background: Type 2 diabetes mellitus is associated with abnormal markers of inflammatory cytokines and oxidative stress markers. Although, these abnormalities could be modulated with weight reduction; there is limitation in clinical studies that have addressed the beneficial effects of weight reduction in modulating biomarkers of inflammatory cytokines and oxidative stress for obesity associated with type 2 diabetes mellitus. Objective: This study was designed to detect the effects of weight loss on the inflammatory cytokines, oxidative stress markers in obese type 2 diabetic patients. Material and Methods: Eighty obese patients with type 2 diabetes mellitus, their age ranged from 35-57 years and their body mass index ranged from 31-35 kg/m2 were equally assigned into 2 groups: the weight reduction group received aerobic exercises, diet regimen, where as the control group received medical treatment only for 12 weeks. Results: The mean values of body mass index (BMI), tumor necrosis factor–alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (sCRP), conjugated dienes (CD) and malondialdehyde (MDA) were significantly decreased, while the mean values of glutathione peroxidase (GPx), superoxide dismutase (SOD) and glutathione (GSH) were significantly increased in patients of group (A), while changes were not significant in group (B). Also, there were significant differences between mean levels of the investigated parameters in group (A) and group (B) at the end of the study. Conclusion: Weight loss ameliorates inflammatory cytokines and oxidative stress markers in obese type 2 diabetic patients.

Influence of magnesium on biochemical parameters of iron and oxidative stress in patients with type 2 diabetes

Introduction: Studies have shown that oxidative stress, found in patients with type 2 diabetes, may be due to changes in the metabolism of minerals, such as magnesium and iron. Data related to compartmentalization of these minerals in diabetes are scarce and controversial. Objective: This study assessed the influence of magnesium on biochemical parameters of iron and oxidative stress in patients with type 2 diabetes. Methods: A case-control study in male and female subjects aged 27-59 years, divided into two groups: type 2 diabetes (n=40) and control (n=48). Intake of magnesium and iron was assessed by three-day food record. Plasma, erythrocyte and urinary levels of magnesium, serum iron, ferritin, total iron binding capacity, fasting glucose, glycated hemoglobin, insulin, creatinine clearance and plasma thiobarbituric acid reactive substances (TBARS) were analyzed. Results and Discussion: Magnesium intake and plasma magnesium were lower in diabetic subjects. There was low urinary magnesium excretion, with no difference between groups. Although normal, the diabetic group had lower serum iron and ferritin concentrations compared to control subjects. Plasma TBARS in diabetic patients was higher than control while creatinine clearance was lower. An inverse correlation between erythrocyte magnesium and serum iron and ferritin was observed in the diabetes group. Conclusions: Diabetes induced hypomagnesemia and this, associated with chronic hyperglycemia, may have enhanced oxidative stress. Erythrocyte magnesium may have contributed to prevent iron overload and worsening of oxidative stress and hyperglycemic status.

Neuroprotective activity of Wedelia calendulacea on cerebral ischemia/reperfusion induced oxidative stress in rats

Objective: This study was undertaken to evaluate the neuroprotective activity of Wedelia calendulacea against cerebral ischemia/reperfusion induced oxidative stress in the rats. Materials and Methods: The global cerebral ischemia was induced in male albino Wistar rats by occluding the bilateral carotid arteries for 30 min followed by 1 h and 4 h reperfusion. At various times of reperfusion, the histopathological changes and the levels of malondialdehyde (MDA), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-s-transferase (GST), and hydrogen peroxide (H(2)O(2)) activity and brain water content were measured. Results: The ischemic changes were preceded by increase in concentration of MDA, hydrogen peroxide and followed by decreased GPx, GR, and GST activity. Treatment with W. calendulacea significantly attenuated ischemia-induced oxidative stress. W. calendulacea administration markedly reversed and restored to near normal level in the groups pre-treated with methanolic extract (250 and 500 mg/kg, given orally in single and double dose/day for 10 days) in dose-dependent way. Similarly, W. calendulacea reversed the brain water content in the ischemia reperfusion animals. The neurodegenaration also conformed by the histopathological changes in the cerebral-ischemic animals. Conclusion: The findings from the present investigation reveal that W. calendulacea protects neurons from global cerebral-ischemic injury in rat by attenuating oxidative stress.

Evaluation of sex specificity on oxidative stress induced in lungs of mice irradiated by C-12(6+) ions

The aim of this work is to identify if there is sex specificity on C-12(6+) ion-induced oxidative damage in mouse lung at different time points. Kun-Ming mice were divided into two groups, each composed of six males and six females: control group and irradiation group with a single acute dose of 4 Gy. Animals were sacrificed at 2, 4 and 12 h respectively, there lungs were removed immediately, and the oxidative stress-related biomarkers were measured by Diagnostic Reagent Kits. The results showed that the relative activities of superoxide dismutase (4 h), catalase (2 h) and Se-dependent glutathione peroxidase (12 h) have significant changes (P < 0.05) between male groups and female groups, suggesting that the lungs of male mice are more sensitive to counteracting the oxidative challenge. Moreover, higher levels of malondiadehyde and lower contents of glutathione were also found in males, indicating that oxidative stress induced by C-12(6+) ion is pronounced in the lungs of males. We thought that these sex-responded differences may be attributed to the influence of sex hormones.

The effect of increased dietary fruit and vegetable consumption on endothelial activation, inflammation and oxidative stress in hypertensive volunteers

Background and aims

Public health campaigns recommend increased fruit and vegetable (FV) consumption as an effective means of cardiovascular risk reduction. During an 8 week randomised control trial among hypertensive volunteers, we noted significant improvements in endothelium-dependent vasodilatation with increasing FV consumption. Circulating indices of inflammation, endothelial activation and insulin resistance are often employed as alternative surrogates for systemic arterial health. The responses of several such biomarkers to our previously described FV intervention are reported here.
Methods and results

Hypertensive volunteers were recruited from medical outpatient clinics. After a common 4 week run-in period during which FV consumption was limited to 1 portion per day, participants were randomised to 1, 3 or 6 portions daily for 8 weeks. Venous blood samples for biomarker analyses were collected during the pre and post-intervention vascular assessments. A total of 117 volunteers completed the 12 week study. Intervention-related changes in circulating levels of high sensitivity C-reactive protein (hsCRP), soluble intracellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), von Willebrand factor (vWF) and plasminogen activator inhibitor-1 (PAI-1) did not differ significantly between FV groups. Similarly, there were no significant between group differences of change in homeostasis model assessment (HOMA) scores.
Conclusions

Despite mediating a significant improvement in acetylcholine induced vasodilatation, increased FV consumption did not affect a calculated measure of insulin resistance or concentrations of the circulating biomarkers measured during this study. Functional indices of arterial health such as endothelium-dependent vasomotion are likely to provide more informative cardiovascular end-points during short-term dietary intervention trials.

Effect of fruit and vegetable intake on oxidative stress and inflammation in COPD: a randomised controlled trial

Epidemiological evidence supports a positive relationship between fruit and vegetable (FV) intake, lung function and chronic obstructive pulmonary disease (COPD). Increasing FV intake may attenuate the oxidative stress and inflammation associated with COPD.

An exploratory randomised controlled trial to examine the effect of increased consumption of FV on oxidative stress and inflammation in moderate-to-severe COPD was conducted. 81 symptomatically stable patients with a habitually low FV intake (two or fewer portions of FV per day) were randomised to the intervention group (five or more portions of FV per day) or the control group (two or fewer portions of FV per day). Each participant received self-selected weekly home deliveries of FV for 12 weeks.

75 participants completed the intervention. There was a significant between-group change in self-reported FV intake and biomarkers of FV intake (zeaxanthin (p=0.034) and ß-cryptoxanthin (p=0.015)), indicating good compliance; post-intervention intakes in intervention and control groups were 6.1 and 1.9 portions of FV per day, respectively. There were no significant changes in biomarkers of airway inflammation (interleukin-8 and myeloperoxidase) and systemic inflammation (C-reactive protein) or airway and systemic oxidative stress (8-isoprostane).

This exploratory study demonstrated that patients with moderate-to-severe COPD were able to comply with an intervention to increase FV intake; however, this had no significant effect on airway or systemic oxidative stress and inflammation.