Incomplete oxygen reduction gives rise to reactive oxygen species (ROS). For a long time they have been considered unwelcome companions of aerobic metabolism. Organisms using oxygen developed several systems of ROS scavenging with enzymatic and non enzymatic antioxidants, which allow them control the cellular level of oxygen derived from free radicals. It is well established nowadays that ROS are not necessarily negative byproducts, but they also play an important role in cellular mechanisms. They are involved in many regular cellular processes in all aerobic organisms. When the antioxidant system is overcome and the balance between ROS production and scavenging is disrupted, oxidative stress occurs. It has been reported that oxidative stress may be linked to some human diseases and is also involved in biotic and abiotic stress response in plants.
Oxidative stress (OxS) has been implicated in the pathogenesis of Crohn’s disease (CD). The aim of this study was to examine whether nonenzymatic antioxidants are associated with active CD, by using the FRAP and GSH assay in plasma. Additionally, we measured bilirubin and albumin levels as two individual components of the plasma antioxidant system. A total of 55 patients with established CD, 30 with active CD and 25 with inactive disease, and 25 healthy individuals were prospectively enrolled in this study. We evaluated CD activity index, BMI and blood morphology, platelet count, serum CRP level, and bochemical parameters of OxS: ferric reducing ability of plasma (FRAP), reduced glutathione (GSH) in plasma and bilirubin and albumin levels in serum. Plasma FRAP and GSH concentrations were decreased in both CD groups compared to controls and negatively correlated with CDAI values (FRAP: r = –0.572, p = 0.003; GSH: r = –0.761, p = 0.001), CRP and platelet count. Bilirubin and albumin levels were lower in the serum of active CD patients than inactive CD patients and controls and negatively correlated with the CD activity index (r = –0328, p = 0.036, r = –0.518, p = 0.002) and CRP (r = –0.433, p = 0.002). The decreased FRAP and GSH levels in plasma and bilirubin and albumin levels in serum of patients with active CD compared to inactive CD and controls underlines the importance of OxS in the pathophysiology and activity of CD.
Growth and photosynthetic characteristics, inducibility of the CAM pathway and the functioning of the antioxidant defense system were investigated in Rosularia elymaitica (Crassulaceae) under drought and UV stresses. Drought did not substantially affect the growth of the plants, but it significantly reduced leaf thickness as well as osmotic potential, water potential and relative water content. In contrast, UV radiation treatment affected neither growth nor the water relations of leaves. Water limitation for 12 days caused a significant increase in nighttime PEPC and NAD-MDH activity and an increase in Δtitratable acidity relative to well-watered plants. The nighttime CO2 net assimilation rate increased significantly in drought-stressed plants but was still negative, resembling a C3-like pattern of gas exchange. Twenty days of UV treatment, increased Δtitratable acidity slightly and increased only daytime PEPC activity, and did not affect other parameters of carbon metabolism. As judged by maintenance of membrane integrity and stable amounts of H2O2 under UV stress, the antioxidant defense system effectively protected the plants against UV radiation. In contrast, oxidative stress occurred under severe drought stress (20 days of withholding water). Except for higher daytime APX activity in the UV-treated plants, enzyme activity in the control and in the drought- and UV-stressed plants did not show any diurnal fluctuation during 24 h. Temporal changes in Δtitratable acidity and ΔPEPC activity coincided closely with those of antioxidant enzymes; both started to increase after 12 days of drought stress. These results indicate that drought stress but not UV radiation induced the CAM-cycling pathway in R. elymaitica.
Oxygen is used for medical treatment and general anesthesia. However, high concentrations of oxygen can have toxic effects on cells. In veterinary medicine, 100% oxygen is usually used during general anesthesia and it can be toxic to animals. However, there is little concern about its harmful effects in humans. The objective of this study was to demonstrate that using a high con- centration of oxygen increases the partial pressure of oxygen in arterial blood (PaO2) more so than a lower concentration, by comparing PaO2 at three different oxygen concentrations (100%, 60%, and 40%) in six dogs under general anesthesia for 3 hours. The mean PaO2 and standard error values at the 100%, 60%, and 40% oxygen concentrations were 535.8 ± 24.01, 374 ± 17.19, and 239 ± 8.78 mmHg, respectively (p<0.05). These results show that 100% and 60% oxygen concentrations could increase oxidative stress. Further studies are needed to examine the oxygen concentration that causes toxicity.
The aim of the present study was to determine changes in oxidative status in plasma of sows during periparturient period using markers of lipid and protein peroxidation intensity. Plasma from 12 pregnant gilts collected on days 14 and 1 before parturition and on days 1, 7 and 14 postpartum was used in the study. As indicators of alterations in the oxidative status, plasma concentrations of thiobarbituric acid reactive substances (TBARS) and sulphydryl groups (SH groups) were measured spectrophotometrically, as well as plasma concentrations of bityrosine and formylokinurenine were determined by the spectrofluorimetric method. Compared to the 14th day antepartum, the concentration of TBARS increased significantly on day 1 postpartum and then decreased significantly on days 7 and 14 after parturition. The concentration of SH groups increased significantly on the last day before parturition and decreased significantly on day 14 postpartum. The concentration of bityrosine increased significantly on the last day before parturition and decreased significantly on days 7 and 14 postpartum. The concentration of formylokinurenine increased significantly on the last day before parturition, remained at this level on the first day after parturition and then decreased slightly on days 7 and 14 postpartum. These results indicate that during periparturient period in sows, especially around the parturition, the oxidative/antioxidative balance is disturbed, which leads to oxidative stress. Considering that oxidative stress is potentially harmful for mothers and neonates, this may be an important factor in the increased risk of diseases occurring during this period.
This study was conducted to determine the serum and milk levels of thiobarbturic acid-reac- tive substances (TBARS), nitric oxide (NO), superoxide dismutase (SOD), glutathione peroxi- dase (GSH-Px), vitamin E and selenium, IL-4 and IL-6 in lactating dairy cows affected with bloody milk using commercially available ELISA kits. Milk and whole blood samples were collected from 60 cows affected with bloody milk and 20 apparently healthy cows for control. In the serum, levels of GSH-Px and SOD were significantly (p˂0.05) higher in healthy cows compared to cows affected with bloody milk while the levels of TBARS and NO were significantly (p˂0.05) higher in affected cows. In the milk, levels of SOD, TBARS and NO were significantly (p˂0.05) higher in affected cows. In the serum, levels of vitamin E were significantly (p˂0.05) lower in affected cows compared to healthy cows, while no significant changes were observed in the levels of this vitamin in the milk between healthy and affected cows. In the serum, levels of selenium were significantly (p˂0.05) lower in affected cows while in milk, selenium levels were significantly (p˂0.05) higher in affected cows compared to healthy ones. Levels of IL-4 were significantly (p˂0.05) lower in the serum and milk of affected cows compared to healthy cows while levels of IL-6 were significantly (p˂0.05) higher in both serum and milk of affected cows. Results of this study suggest a possible role of oxidative stress in the pathogenesis of bloody milk in dairy cows.
The aim of the present study was to determine the concentrations of glutathione (GSH), vitamin C, copper (Cu) and zinc (Zn) in the uterine tissues in diagnosis of canine pyometra. Fourteen samples of uterine tissues from female dogs with pyometra and twelve samples of healthy uteruses (control) were used. The concentrations of GSH and vitamin C were determined in the uterine tissue homogenates using spectrophotometric methods. The concentrations of Cu and Zn were measured using atomic absorption spectrometer. The results obtained showed the significantly lower (p<0.05) concentration of GSH and the trend towards lower concentration of vitamin C in the pyometra samples compared to the control. The concentrations of Cu and Zn were similar in the uterine tissues from female dogs with pyometra and those from healthy female dogs. The lower GSH and vitamin C concentrations in the uterine tissues of female dogs with pyometra indicate that the non-enzymatic antioxidant mechanisms are impaired in the uterus of dogs with pyometra. These findings suggest that the imbalance of oxidative-antioxidative can play an important role in pathogenesis of canine pyometra.
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