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Oxidative stress, caused by increased levels of reactive oxygen species (ROS)and reactive nitrogen species (RNS) and/or a decrease in antioxidant capacity, can result in the oxidation of various bio-molecules, such as proteins, lipids and deoxyribonucleic acid (DNA). These oxidized bio-molecules may contribute to pathologies such as cardiovascular diseases, neurodegenerative disorders and cancer. The Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA) study was initiated in 2008 to investigate the coping styles and catecholamine metabolic markers of Africans, contributing to their higher sympathetic output and poorer psychosocial wellbeing. This study forms part of the SABPA study, but with a specific aim to investigated lipid and protein oxidation markers in hypertensive Africans versus their normotensive counterparts. Analytical methods for the quantification of specific lipid and protein oxidation markers were optimized and validated. Urine samples from 172 urbanized black South Africans were collected and 3-nitrotyrosine (3NT) and thiobarbituric acid reactive substances (TBARS) were quantified in these samples, using the optimized spectrophotometric and LC-MS/MS methods. Statistical analyses showed that in both males and females, TBARS and 3NTcorrelated with each other. In males, 3NT also correlated with physical activity level (PAL) and C-reactive protein (CRP), while TBARS also correlated with body mass index (BMI). In females 3NT correlated with BMI, while TBARS correlates with PAL. These correlations meant that they could influence the calculations of the true effect of 3NT and TBARS levels between normotensive and hypertensive subjects. After analyses of covariance (ANCOVA) analyses it was determined that the hypertensive male subjects had higher TBARS values than the normotensive male subjects did (p-value = 0.03) and the normotensive female subjects had higher 3NT levels compared to the hypertensive female subjects (p-value = 0.04). These results partially supported the hypothesis that that elevated concentrations of specific urinary lipid and protein oxidation markers will be observed in the hypertensive test subjects compared to their normotensive counterparts. The results also indicated that there were indeed a difference in lipid and protein oxidation between hypertensive and normotensive subject. / Thesis (MSc (Biochemistry))--North-West University, Potchefstroom Campus, 2013

Oxidative stress, caused by increased levels of reactive oxygen species (ROS)and reactive nitrogen species (RNS) and/or a decrease in antioxidant capacity, can result in the oxidation of various bio-molecules, such as proteins, lipids and deoxyribonucleic acid (DNA). These oxidized bio-molecules may contribute to pathologies such as cardiovascular diseases, neurodegenerative disorders and cancer. The Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA) study was initiated in 2008 to investigate the coping styles and catecholamine metabolic markers of Africans, contributing to their higher sympathetic output and poorer psychosocial wellbeing. This study forms part of the SABPA study, but with a specific aim to investigated lipid and protein oxidation markers in hypertensive Africans versus their normotensive counterparts. Analytical methods for the quantification of specific lipid and protein oxidation markers were optimized and validated. Urine samples from 172 urbanized black South Africans were collected and 3-nitrotyrosine (3NT) and thiobarbituric acid reactive substances (TBARS) were quantified in these samples, using the optimized spectrophotometric and LC-MS/MS methods. Statistical analyses showed that in both males and females, TBARS and 3NTcorrelated with each other. In males, 3NT also correlated with physical activity level (PAL) and C-reactive protein (CRP), while TBARS also correlated with body mass index (BMI). In females 3NT correlated with BMI, while TBARS correlates with PAL. These correlations meant that they could influence the calculations of the true effect of 3NT and TBARS levels between normotensive and hypertensive subjects. After analyses of covariance (ANCOVA) analyses it was determined that the hypertensive male subjects had higher TBARS values than the normotensive male subjects did (p-value = 0.03) and the normotensive female subjects had higher 3NT levels compared to the hypertensive female subjects (p-value = 0.04). These results partially supported the hypothesis that that elevated concentrations of specific urinary lipid and protein oxidation markers will be observed in the hypertensive test subjects compared to their normotensive counterparts. The results also indicated that there were indeed a difference in lipid and protein oxidation between hypertensive and normotensive subject. / Thesis (MSc (Biochemistry))--North-West University, Potchefstroom Campus, 2013

Protein nitration is considered as a marker of reactive nitrogen species formation. Heme oxygenases (HOs) are important for the defence against oxidative stress. We evaluated the involvement of the neuronal (nNOS), the endothelial (eNOS), and the inducible (iNOS) in nitrotyrosine formation and localitzation, and both the expression and funcional significance (HO inhibition and contractility studies) of HOs in sepsis-induced muscle contractile dysfunction. Sepsis was elicited by injecting rats and transgenic mice deficient in either nNOS, eNOS, or iNOS isoforms with E.Coli lipolysaccharide (LPS). Nitrotyrosine formation and HO expressions were assessed by immunoblotting. Oxidative stress was assessed measuring protein oxidation, lipid peroxidation, and muscle glutathione. We conclude that protein tyrosine nitration occurs in normal muscles, and sepsis-mediated increase in nitrotyrosine formation is limited to the mitochondria and membrane muscle fractions. The iNOS isoform is mostly involved in nitrotyrosine formation. HOs protect normal and septic muscles from the deleterious effects of oxidants. / En un model de sepsi de disfunció diafragmàtica, s´ha avaluat el paper de les sintetases de l'òxid nítric (NOS) en la formació i localitzacio de 3-nitrotirosina, i l´expressió i significat biològic de les hemo oxigenases (HOs) (inhibidor de les HOs i estudis de contractilitat) davant l' estrès oxidatiu. La sepsi s'induí mitjançant injecció de 20 mg/kg del lipolisacàrid (LPS) d´Escherichia Coli a rates, i a ratolins deficients en les NOS induïble (iNOS), neuronal (nNOS) i endotelial (eNOS). Les proteïnes nitrificades i les HOs es van detectar amb anticossos específics. L' estrès oxidatiu s' avaluà mitjançant l' oxidació proteica, la peroxidació lipídica i el glutation muscular. Concloem que hi han proteïnes nitrificades en el múscul normal i aquestes s'incrementen durant la sepsi en les fraccions mitocondrial i membranar. L'isoforma iNOS és majorment responsable de la formació de nitrotirosina. Les HOs protegirien el múscul normal i sèptic dels efectes deleteris dels oxidants.