A novel automated direct measurement method for total antioxidant capacity using a new generation, more stable ABTS radical cation

Letrozole induces hepatotoxicity without causing oxidative stress: the protective effect of melatonin

AIM

The aim of this study was to determine the effects of letrozole (LTZ), an aromatase inhibitor (AI), and melatonin (MLT) on hepatic function and oxidative stress in female rats.

MATERIAL AND METHODS

A total of 32 female rats were divided equally into four groups (n = 8). Control group received saline (0.5 ml/day, oral gavage). LTZ was administered to rats by daily oral gavage at 1 mg/kg dose. LTZ + MLT group was given LTZ (1 mg/kg, oral gavage) plus MLT (0.5 mg/kg/day, s.c.). MLT group was given MLT (0.5 mg/kg/day) by s.c. injection. The activities of superoxide dismutase (SOD) and catalase (CAT) and malondialdehyde (MDA) levels were measured in liver tissue. Total antioxidant capacity (TAC), total oxidant status (TOS), ALT, AST, GGT, ALP, LDH, bilirubin, BUN, creatinine, total cholesterol (TC), high-density lipoprotein (HDL) and triglyceride (TG) were assayed in serum samples.

RESULTS

The oxidative stress parameters did not differ between groups. LTZ administration increased hepatic function parameters such as AST, LDH, ALP, bilirubin and MLT improved the disturbances of hepatic function. LTZ caused minimal histological changes in liver tissue and MLT treatment reversed those dejenerations.

DISCUSSION

LTZ may cause hepatotoxicity without inducing oxidative stress and MLT restores hepatic activity.

Oxidative and carbonyl stress in patients with obstructive sleep apnea treated with continuous positive airway pressure

PURPOSE

The pathogenesis of cardiovascular complications of obstructive sleep apnea syndrome (OSAS) can be explained by oxidative and carbonyl stress due to oxygenation and reoxygenation injury during sleep. This hypothesis has yet to be proved experimentally, although several clinical observations have found increased oxidative damage in plasma. Continuous positive airway pressure (CPAP) improves symptoms and prognosis of patients with OSAS.

METHODS

Patients with confirmed SAS (n = 89) underwent polysomnography and received CPAP treatment. Plasma and saliva samples were taken before CPAP therapy as well as after 1 and 6 months of CPAP treatment. Selected markers of oxidative and carbonyl stress were measured in plasma and saliva, and their dynamics was statistically analyzed.

RESULTS

Plasma levels of thiobarbituric acid reacting substances-a marker of lipoperoxidation-and advanced glycation end products (AGEs)-a marker of carbonyl stress-were decreased by the CPAP therapy. The decrease of AGEs and fructosamine was also found in saliva. Interestingly, no gender differences and no changes of antioxidant status measured as total antioxidant capacity and ferrous reducing ability were found in either of the samples.

CONCLUSION

Previous findings of lowered plasma markers of oxidative stress were confirmed. Plasma AGEs were lowered by CPAP therapy. This is the first study analyzing markers of oxidative and carbonyl stress in saliva. Non-invasive sampling of saliva makes it a very interesting source of information for repeated monitoring of therapy success. Salivary AGEs and fructosamine as markers of carbonyl stress were decreased by the CPAP therapy and might therefore have potential informative value for clinical observations, as well as for the understanding of the pathogenesis of OSAS complications.

Evaluation of oxidant and antioxidant status in infants with hyperbilirubinemia and kernicterus

Objective: The objective of the present study was to determine oxidant and antioxidant status in infants with hyperbilirubinemia and/or kernicterus and to find whether there is a relationship between bilirubin level and oxidant/antioxidant status. Patients: The study includes 69 full-term newborns (neonates with hyperbilirubinemia needing phototherapy [Group 1, n = 36] and neonates with kernicterus [Group 2, n = 33]) and 25 age-matched healthy newborn. Results: Plasma total antioxidant capacity (TAC) and serum total oxidant status (TOS) were significantly higher in Groups 1 and 2 than the control group. There was a significant difference between Group 1 and control cases for malondialdehyde (MDA; p < 0.001). Total free sulfhydryl group (TTHI) values were significantly elevated in Group 1 compared to Group 2 and control cases. Correlation analysis showed that the correlation between total bilirubin (TB) and TAC, TOS, MDA and oxidative stress index may be expressed by a quadratic curve. After phototherapy, a statistically significant increase in nitrite level was observed. Conclusion: We demonstrated that the relationship between serum TB and antioxidants and oxidative stress could be expressed by a quadratic correlation curve.

Effect of Ramadan fasting on maternal oxidative stress during the second trimester: a preliminary study

AIM

To evaluate whether fasting during Ramadan has any significant effects on maternal oxidative stress or fetal health in healthy, pregnant women with an uncomplicated, second-trimester, singleton pregnancy.

METHODS

During the month of Ramadan, 1-29 September 2008, 42 fasting and 30 non-fasting pregnant women were enrolled in this prospective controlled study. Total antioxidant status (TAS), total oxidant status (TOS) and the oxidative stress index (OSI) were measured from maternal serum samples taken on a fasting day during Ramadan. The two groups underwent routine follow-up examinations. At the end of the pregnancy, maternal complications, birth weight and maternal weight gain during the entire pregnancy were noted. To evaluate whether the duration of fasting days (≥10 or ≥15 days) had any significant effects on maternal oxidative stress, pregnant women who observed Ramadan for more than nine days or those who fasted for more than 14 days were compared with the control group in terms of TAS, TOS and OSI.

RESULTS

No significant differences were observed between the groups studied in terms of TAS, TOS, OSI, maternal age, gestational age, parity, birth weight or weight gain during the pregnancy. The TAS level was evaluated as significantly higher (P = 0.027) in the ≥10 fasting days group compared to the non-fasting control group, while there were no significant differences between the groups with respect to TOS and OSI.

CONCLUSION

Maternal fasting during Ramadan during the second trimester does not have a significant effect on maternal oxidative stress, fetal development or fetal birth weight.

Exercise Training and Antioxidants

We have investigated the cardioprotective effects of exercise training and/or curcumin on lead acetate-induced myocardial damage. Forty rats were randomly divided into 5 groups: (1) lead acetate, (2) curcumin, (3) endurance training, (4) training + curcumin, (5) sham groups. The rats in groups 3 and 4 experienced the treadmill running of 15 to 22 m/min for 25 to 64 minutes, 5 times a week for 8 weeks. Groups 1 to 4 received lead acetate (20 mg/kg), the sham group received curcumin solvent (ethyl oleat), and the curcumin and training + curcumin groups received curcumin solution (30 mg/kg) intraperitoneally. Lead administration resulted in significant increases in high-sensitivity C-reactive protein (hs-CRP), creatine kinase-MB (CK-MB), malondialdehyde (MDA), and low-density lipoprotein (LDL), and significantly decreased glutathione peroxidase (GPx), Total Antioxidant Capacity (TAC), and high-density lipoprotein (HDL) levels. Treadmill running and\or curcumin supplementation resulted in a significant decrease in hs-CRP, CK-MB, MDA, and LDL levels and significantly increased GPx, TAC, and HDL levels. These results suggest a lifestyle-induced cardioprotective potential in ameliorating lead-induced cardiotoxicity.

Decreasing oxidative stress in response to treatment in patients with brucellosis: could it be used to monitor treatment?

OBJECTIVES

The aims of this study were to evaluate oxidant and antioxidant status in patients with acute brucellosis before and after therapy, and to determine whether this index could be used to monitor the treatment of brucellosis.

METHODS

Thirty patients with a diagnosis of acute brucellosis and 37 healthy volunteers were enrolled in the study. Total antioxidant status (TAS) and total oxidant status (TOS) were measured in patients before and after therapy, and an oxidative stress index (OSI) was calculated. These measurements were also taken for the healthy control group and the values were compared.

RESULTS

Plasma levels of TOS and OSI were significantly higher in patients with brucellosis before therapy as compared to the treated group (t: 11.19, p<0.000 and t: 9.91, p<0.000, respectively). After treatment, TOS and OSI levels were lower, whereas in contrast, TAS levels were significantly higher (t: -4.17, p<0.000). TOS and OSI levels were found to be significantly higher in the patients before treatment than in the control group (t: 15.01, p<0.000 and t: 15.00, p<0.000, respectively). TAS levels in patients before treatment were lower than in the controls and the difference was significant (t: -8.03, p<0.000). TOS and OSI levels were significantly higher in the treated group than in the control group (t: 4.58, p<0.000 and t: 9.91, p<0.000, respectively). TAS levels in the treated group were lower than in the control group and the difference was significant (t: -3.02, p<0.004).

CONCLUSION

Reduced TAS capacity and elevated TOS levels may lead to considerable oxidative stress in brucellosis. Increased oxidative stress may cause severe oxidative damage in the body, and even though this damage ameliorates considerably with 6weeks of treatment, normal healthy levels are not attained. In addition, it appears possible that these oxidant and antioxidant parameters could be used to monitor treatment.

Measurement of the placental total antioxidant status in preeclamptic women using a novel automated method

AIM

We aimed to measure the levels of total antioxidant status (TAS) in placental samples from preeclamptic pregnant women and evaluate the relation of placental TAS, total oxidant status (TOS) and oxidative stress index (OSI) with fetomaternal compartments using the more recently designated Erel method.

MATERIAL AND METHODS

Thirty four preeclamptic and 27 normotensive pregnant women were enrolled in this prospective controlled study. Subjects were selected from women attending the Obstetrics and Gynecology Department of Gaziantep University. TAS, TOS, OSI were measured from placental, maternal and cord blood samples using a novel automated method. Statistical analyses were performed with SPSS for Windows version 13.0 (SPSS Inc., Chicago, IL, USA).

RESULTS

The TAS level of the placenta was evaluated as significantly lower (P<0.001) in preeclamptic women compared to normotensive women. In preeclamptic pregnancies, while the placental TAS level was not correlated with placental TOS level, the TAS levels of maternal plasma (P<0.001; r=0.584) and cord plasma (P<0.005; r=0.529) were significantly correlated with the TOS level of the placenta.

CONCLUSION

Our results support the concept that placental defective response to an oxidant stimulus plays a central role in the etiopathogenesis of preeclampsia by using the novel automated Erel method.

The effects of the mode of delivery on oxidative-antioxidative balance

OBJECTIVE

The purpose of this study was to investigate the effects of the mode of delivery on the oxidant and antioxidant systems in mothers and infants and to demonstrate which mode leads more oxidative stress.

METHODS

The participants were divided into two groups according to the mode of their labour and delivery: group 1 (n = 33) women with normal labour and delivery and group 2 (n = 33) with scheduled caesarean section (C/S) and delivery. The maternal, cord, and infant blood samples in both groups were collected. The serum total antioxidant capacity (TAC) and the total oxidant status (TOS) were evaluated by using an automated colorimetric measurement method.

RESULTS

The parameters indicating oxidative stress (TOS, oxidative stress index, and lipid hydroperoxide) in maternal, cord, and newborn blood samples were higher in patients delivering with C/S than those normal spontaneous vaginal deliveries (NSVD) patient group, while it was vice versa for TAC.

CONCLUSIONS

It may be concluded that both the mothers and neonates in C/S group are exposed to higher oxidative stress as compared with those in NSVD group and the antioxidant mechanisms are insufficient to cope with this stress during C/S. This result indicates that the normal delivery through the physiological route is healthier for the bodies of mothers and infants.

The effect of ascorbic acid supplementation on endosulfan toxicity in rabbits

We investigated the endosulfan-induced alterations and the effect of vitamin C supplementation on endosulfan-induced alterations in serum biochemical markers of oxidative stress and antioxidant capacity in rabbits. Basal, 4th and 6th week serum levels of total oxidant status (TOS), thiobarbituric acid reactive substances (TBARS), advanced oxidation protein products (AOPP), total antioxidant capacity (TAC), total protein sulfhydryl (T-SH) and glutathione-S-transferase (GST) were measured in rabbits administered endosulfan (1 mg/kg) alone or in combination with vitamin C (20 mg/kg) for 6 weeks. Control rabbits received either vehicles or vitamin C. Serum TOS, TBARS and AOPP levels at 4th and 6th week were significantly higher whereas T-SH levels were significantly lower than basal values in endosulfan-administered rabbits. GST increased significantly at 4th week but decreased below basal value at 6th week. Similarly, TAC decreased significantly at 6th week. Vitamin C supplementation increased TAC at 4th and 6th weeks in controls and increased T-SH and GST and decreased TOS, TBARS and AOPP at 4th week in endosulfan-administered rabbits. TAC increased significantly at 6th week by vitamin C supplementation in endosulfan-administered rabbits. There were significant increments in TBARS and decrements in TAC and GST levels at 6th week compared to 4th week in endosulfan-administered rabbits. Present findings indicated to an increased and progressively uncompensated oxidant stress in endosulfan-administered rabbits that was substantially ameliorated by vitamin C supplementation through an improvement in antioxidant capacity. It was suggested that vitamin C supplementation might be helpful in preventing the detrimental effects of increased oxidative stress caused by endosulfan exposure.

Umbilical cord oxidative stress in infants of diabetic mothers and its relation to maternal hyperglycemia

AIMS

There is growing body of evidence that oxidative stress plays an important role in the pathogenesis of diabetes mellitus (DM) and in development of maternal and fetal complications of diabetic pregnancies. The aim of the present study was to investigate total antioxidant capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) in infants of diabetic mothers (IDM) and to reveal the influence of maternal hyperglycemia on these parameters.

METHODS

A prospective controlled study was conducted between March 2010 and November 2010. Umbilical cord blood was taken from IDM and controls for TAC and TOS measurement, and OSI was calculated. IDM were divided into two groups, either of mothers treated with insulin during pregnancy or of those treated with a carbohydrate-restricted diet.

RESULTS

Thirty-six IDM and 14 infants born to non-diabetic mothers were enrolled. Infants of insulin-treated mothers (group 1) and infants of mothers managed with a carbohydrate-restricted diet (group 2) had significantly higher TOS (p < 0.001 and p = 0.001, respectively) and OSI (p < 0.001 and p = 0.001, respectively) levels compared to controls. However, TAC levels were similar in all three groups. Maternal HbA(1c) values were correlated to TOS (p < 0.001, r = 0.694) and OSI (p < 0.001, r = 0.683).

CONCLUSIONS

Oxidative stress is increased in IDM, and a significant relation exists between the degree of maternal hyperglycemia in pregnancy and oxidative stress in the newborn at birth.

Effect of chronic regular exercise on serum ischemia-modified albumin levels and oxidative stress in type 2 diabetes mellitus

Objectives. Our aim was to determine the effect of chronic regular exercise on ischemia-modified albumin (IMA) levels and oxidative stress in type 2 diabetes mellitus (DM). Design and methods. Sixty patients with type 2 DM were randomly divided into two groups as exercise (17 M, 13 F) and non-exercise (12 M, 18 F) groups, each consisting of 30 patients. The exercise group underwent a 3-month aerobic regular exercise consisting of moderate-intensity power walking. The non-exercise subjects remained sedentary throughout the study period. Serum total antioxidant status (TAS), total oxidant status (TOS), and IMA levels of the groups were determined at baseline and 3 months later. Results. There was no significant change in TOS and IMA levels of exercise group but TAS levels were significantly increased (p < 0.05). Also, postexercise systolic (p < 0.001) and diastolic (p < 0.05) blood pressures of the exercise group were significantly lower than the baseline values. In addition, there was no significant change in TAS and TOS levels of the non-exercise group; however, IMA levels were significantly increased (p < 0.01). Conclusion. We have shown, for the first time, that exercise prevents increase in IMA levels in type 2 DM which might have resulted from increased levels of TAS and reduces the risk of ischemia in these patients. These findings show that chronic exercise is beneficial in the prevention of oxidative stress in patients with type 2 DM as documented by decreased IMA levels.

Antioxidant activities of total phenols of Prunella vulgaris L. in vitro and in tumor-bearing mice

Prunella vulgaris L. (PV, Labiatae) is known as a self-heal herb. The different extracts of dried spikes were studied for the best antioxidant active compounds. The 60% ethanol extract (P-60) showed strong antioxidant activity based on the results of 2,2'-azino-di(3-ethylbenzthiazoline-6-sulfonic acid (ABTS˙+), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assay methods. High performance liquid chromatography (HPLC) and LC/MS analysis showed that the main active compounds in P-60 were phenols, such as caffeic acid, rosmarinic acid, rutin and quercetin. Total phenols were highly correlated with the antioxidant activity (R2=0.9988 in ABTS˙+; 0.6284 in DPPH and 0.9673 FRAP tests). P-60 could inhibit significantly the tumor growth in C57BL/6 mice. It can also been showed that increased superoxide dismutase (SOD) activity and decreased malondialdehyde (MDA) content in serum of tumor-bearing mice. These results suggested that P-60 extract had high antioxidant activity in vitro and in vivo and total phenols played an important role in antioxidant activity for inhibition of tumor growth.

Effects of extremely low-frequency magnetic field on caspase activities and oxidative stress values in rat brain

This study was aimed to investigate the effect of extremely low-frequency magnetic field (ELF-MF) on apoptosis and oxidative stress values in the brain of rat. Rats were exposed to 100 and 500 µT ELF-MF, which are the safety standards of public and occupational exposure for 2 h/day for 10 months. Brain tissues were immunohistochemically stained for the active (cleaved) caspase-3 in order to measure the apoptotic index by a semi-quantitative scoring system. In addition, the levels of catalase (CAT), malondialdehyde (MDA), myeloperoxidase (MPO), total antioxidative capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) were measured in rat brain. Final score of apoptosis and MPO activity were not significantly different between the groups. CAT activity decreased in both exposure groups (p < 0.05), while TAC was found to be lower in ELF 500 group than those in ELF-100 and sham groups (p < 0.05). MDA, TOS, and OSI values were found to be higher in ELF-500 group than those in ELF-100 and sham groups (p < 0.05). In conclusion, apoptosis was not changed by long-term ELF-MF exposure, while both 100 and 500 µT ELF-MF exposure induced toxic effect in the rat brain by increasing oxidative stress and diminishing antioxidant defense system.

Endocrine disrupting, haematological and biochemical effects of polybrominated diphenyl ethers in a terrestrial songbird, the European starling (Sturnus vulgaris)

We exposed female European starlings (Sturnus vulgaris) during a 6month period to environmentally relevant concentrations of a pentabromodiphenyl ether (Penta-BDE) mixture (about 1740μg/kg body weight) through subcutaneous implants, and examined endocrine disruptive, haematological and biochemical effects. To investigate endocrine disrupting effects of PBDEs, testosterone, estradiol and thyroid hormones (T(3) and T(4)) were measured in the plasma. We found no significant differences between the control and exposed groups for any of the hormones. However, 14days after implantation, T(3) concentrations tended to be lower in the exposed group compared to the control group. For albumin, our results suggest that short term exposure of PBDEs may result in a negative effect on albumin, while the opposite was observed on a longer term (6months after implantation). However, from the statistical analysis, effects on albumin disappeared when excluding females that laid eggs. These results demonstrate that observed effects during the breeding season should be interpreted carefully when the breeding status of females is unknown. There were no significant differences found between the control and exposed groups for the other biochemical parameters (total protein, uric acid, cholesterol, aspartate transaminase, total antioxidative capacity, high-density lipoproteins and creatine kinase) and haematological parameters (amount of red blood cells, haemoglobin concentration, haematocrit, mean corpuscular volume and mean corpuscular haemoglobin). All together, our results suggest that European starlings, similar to other passerine species, may be less sensitive to the effects of organohalogenated pollutants, such as PBDEs, than other bird species.

Oxidative stress increases in carbon monoxide poisoning patients

OBJECTIVE

Carbon monoxide poisoning (COP) is one of the important causes of morbidity and mortality in toxicological cases. In this study, we aimed to find out more about the pathophysiology of COP by investigating the effects of COP on oxidative stress parameters such as total oxidant status (TOS) and total antioxidant status (TAS).

METHODS

Eighty-eight patients admitted to the emergency department of our hospital with acute COP and 35 healthy adults as control group were included in this study. Blood samples were collected from all COP patients at the time of initial emergency department evaluation to determine the oxidative stress parameters. Then, serum levels of total antioxidant status and total oxidant status levels were measured.

RESULTS

A total of 88 patients poisoned by carbon monoxide (CO; mean age 37.1 ± 18.2 years; 54'% women) were enrolled. TOS and carboxyhemoglobin (COHb) levels in COP patients were increased when compared to control group (p = 0.001). TOS, oxidative stress index (OSI) and COHb levels in COP patients were significantly lower after the treatment. (respectively, p = 0.016; p = 0.023; p = 0.001). On the other hand, no statistical differences were observed in TAS levels of study and control group as well as there were no changes with treatment.

CONCLUSION

Measurements of TOS, TAS and OSI levels may be useful markers to find out the pathophsiology of COP.

Renal and metabolic effects of three months of decarbonated cola beverages in rats

Epidemiological studies have shown an association between the intake of cola beverages and chronic kidney diseases. Experimental evidence for the negative effects of cola intake on kidneys is lacking. Male Wistar rats had ad libitum access to water (control group) or three different sugar-sweetened cola beverages for three months. Despite very high cola intake (daily cca 140 mL), no differences were found in body weight, kidney weight, glomerular morphology, oxidative and carbonyl stress or expression of selected marker genes in the renal cortex. Interestingly, all groups consuming cola beverages had lower blood glucose levels during an oral glucose tolerance test, suggesting improved insulin sensitivity. Despite hyperfiltration (5–6-fold increase in diuresis), cola beverages had no effect on assessed parameters of renal function, histology, gene expression or oxidative stress. Moreover, cola intake seems to increase creatinine clearance and to decrease plasma levels of urea. In our study increased insulin sensitivity and altered renal functional parameters were observed in rats receiving cola beverages for three months. Whether the findings are due to the short duration of the study or interspecies metabolic differences should be uncovered in further studies. Even more interesting might be the analysis of effects of cola intake in animal models of diabetes.

Antioxidant machinery differs between melanic and light nestlings of two polymorphic raptors

Colour polymorphism results from the expression of multiallelic genes generating phenotypes with very distinctive colourations. Most colour polymorphisms are due to differences in the type or amount of melanins present in each morph, which also differ in several behavioural, morphometric and physiological attributes. Melanin-based colour morphs could also differ in the levels of glutathione (GSH), a key intracellular antioxidant, because of the role of this molecule in melanogenesis. As GSH inhibits the synthesis of eumelanin (i.e. the darkest melanin form), individuals of darker morphs are expected to have lower GSH levels than those of lighter morphs. We tested this prediction in nestlings of two polymorphic raptors, the booted eagle Hieraaetus pennatus and the Eleonora's falcon Falco eleonorae, both of which occur in two morphs differing in the extent of eumelanic plumage. As expected, melanic booted eagle nestlings had lower blood GSH levels than light morph eagle nestlings. In the Eleonora's falcon, however, melanic nestlings only had lower GSH levels after controlling for the levels of other antioxidants. We also found that melanic female eagle nestlings had higher levels of antioxidants other than GSH and were in better body condition than light female eagle nestlings. These findings suggest an adaptive response of melanic nestlings to compensate for reduced GSH levels. Nevertheless, these associations were not found in falcons, indicating species-specific particularities in antioxidant machinery. Our results are consistent with previous work revealing the importance of GSH on the expression of melanic characters that show continuous variation, and suggest that this pathway also applies to discrete colour morphs. We suggest that the need to maintain low GSH levels for eumelanogenesis in dark morph individuals may represent a physiological constraint that helps regulate the evolution and maintenance of polymorphisms.

Impaired glomerular and tubular antioxidative defense mechanisms in nephrotic syndrome

The molecular mechanisms behind acquired nephrotic syndrome (NS) are still largely unknown. One possible explanation for the development of proteinuria is oxidative damage to the glomerular cells. Our hypothesis was that the oxidative defense is weakened in NS, and we focused on measurements of the oxidative-antioxidative status in the glomerular and tubular parts of the nephron. Gene expression was analyzed in renal biopsies from patients with NS. In addition, to compare the acute and chronic phases of the disease, we studied puromycin-treated rats. In the biopsy material, the expression of enzymes involved in the antioxidative defense was higher in the tubulointerstitial compartment than in the glomerular cells. Real-time PCR analysis revealed a decreased glomerular expression in nephrotic kidneys for the antioxidant enzymes catalase and glutathione peroxidase-3, and -4. The tubular gene expression was downregulated for catalase, glutathione peroxidase-3, and thioredoxin reductase-1 and -2. The altered gene expression was accompanied by increased lipid peroxidation in urine. In rats, serum concentrations of ascorbyl-free radicals, measured with electron spin resonance, were elevated in the acute phase of the disease, suggesting increased oxidative stress in the circulation. In addition, we saw an increase in the plasma antioxidant capacity combined with a decreased oxidation of proteins in sera from nephrotic rats, but not from humans. In conclusion, there is a marked downregulation of several antioxidative enzymes in nephrotic kidneys, especially in glomerular structures. Our data suggest that oxidative damage to glomerular cells may contribute significantly to the course and prognosis of nephrotic syndrome.

The redox status of experimental hemorrhagic shock as measured by cyclic voltammetry

Hemorrhagic shock (HS) leads to reactive oxygen species production. However, clinicians do not have access to bedside measurements of the redox status during HS. Cyclic voltammetry (CyV) is a simple electrochemical method of measuring redox status. The aims of this study were to 1) report the first application of cyclic voltammetry to measure the acute changes in serum redox status after HS, 2) to contrast it with another severe systemic disease with a different redox pathology (acute pancreatitis [AP]), and 3) to describe the response of CyV over time in a resolving model of AP. In the acute study, 24 male Wistar rats were randomized into three groups: groups 1 (control), 2 (AP), and 3 (HS). In the time-course study, 28 rats were randomized to a sham-control as well as 6 and 24 h post-AP cohorts, respectively.Cyclic voltammetry was performed using a three-electrode system. In the acute study, the first and second voltammetric peaks increased significantly in HS. In contrast, within the AP group, only the first voltammetric peak showed a significant increase. The first voltammetric peak correlated with plasma protein carbonyls (PCs) and with thiobarbituric acid-reactive substances, whereas the second voltammetric peak correlated positively with plasma protein carbonyls. In the second study, the first voltammetric peak correlated with physiological improvements. Here, we showed that serum CyV could respond to the serum redox change in HS and AP. Cyclic voltammetry warrants evaluation as a potential real-time beside measure of a patient's redox status during shock.

Oxidative stress in anxiety and comorbid disorders

Anxiety disorders, depression, and alcohol use disorder are common neuropsychiatric diseases that often occur together. Oxidative stress has been suggested to contribute to their etiology. Oxidative stress is a consequence of either increased generation of reactive oxygen species or impaired enzymatic or non-enzymatic defense against it. When excessive it leads to damage of all major classes of macromolecules, and therefore affects several fundamentally important cellular functions. Consequences that are especially detrimental to the proper functioning of the brain include mitochondrial dysfunction, altered neuronal signaling, and inhibition of neurogenesis. Each of these can further contribute to increased oxidative stress, leading to additional burden to the brain. In this review, we will provide an overview of recent work on oxidative stress markers in human patients with anxiety, depressive, or alcohol use disorders, and in relevant animal models. In addition, putative oxidative stress-related mechanisms important for neuropsychiatric diseases are discussed. Despite the considerable interest this field has obtained, the detailed mechanisms that link oxidative stress to the pathogenesis of neuropsychiatric diseases remain largely unknown. Since this pathway may be amenable to pharmacological intervention, further studies are warranted.

Direct and indirect effects of kisspeptin on liver oxidant and antioxidant systems in young male rats

Kisspeptin is a recently discovered hypothalamic peptide which plays an important role in the central control of reproductive functions. We have investigated direct and indirect effects of kisspeptin on the liver oxidative stress in young male rats. Twenty-four rats were divided into four groups (n = 6/group). First group served as control and received saline. Kisspeptin-10 was administered to the animals in the second group (20 nmol/rat/day), for a period of 7 days. Rats were given only one dose gosereline (0.9 mg/rat), a GnRH agonist in the third group. The last group received kisspeptin-10 with gosereline. The activities of catalase, superoxide dismutase (SOD), xanthine oxidase (XO), adenosine deaminase (AD) and level of malondialdehyde were studied in liver tissue. Serum samples were separated for total antioxidant capacity (TAC), total oxidant status (TOS), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, blood urea nitrogen (BUN), colesterol, high-density lipoprotein (HDL) and triglyceride. Kisspeptin increased the activities of SOD and catalase (p < 0.05). When compared to the control group, the levels of malondialdehyde, TOS and AST were lower, but levels of BUN, cholesterole, HDL and AD were higher in the other three groups (p < 0.05). In conclusion, our findings suggest that kisspeptin may have antioxidant and thus protective effects on the liver tissue.

Protective effects of thymoquinone against methotrexate-induced testicular injury

Thymoquinone is the major active component derived from Nigella sativa. Methotrexate is a folic acid antagonist widely used in clinic. Aim of this study was to investigate the possible protective role of thymoquinone on testicular toxicity of methotrexate. Experiments were performed on male C57BL/6 mice (6 weeks old, 20 ± 2 g). The animals were divided into four groups with six mice in each group. Equivalent volumes of saline were injected intraperitoneally (i.p.) in the control group. In the thymoquinone group, mice received thymoquinone i.p. with a dose of 10 mg/kg/day for 4 days. Mice in the methotrexate group received single dose of methotrexate i.p., with a dose of 20 mg/kg. Finally, in the methotrexate plus thymoquinone group, in the first and the following 3 days after methotrexate administration, thymoquinone was injected with a dose of 10 mg/kg/day, i.p. At the end of the experiment, the left testis was quickly removed and divided into two parts for histological examination and biochemical analysis. Methotrexate alone increased total antioxidant capacity and myeloperoxidase activity compared to the controls. Thymoquinone treatment decreased total antioxidant capacity and prevented the increase in the myeloperoxidase activity. Light microscopy showed in mice that receiving methotrexate resulted in interstitial space dilatation, edema, severe disruption of the seminiferous epithelium and reduced diameter of the seminiferous tubules. Administration of thymoquinone reversed histological changes of methotrexate significantly. We suggest that thymoquinone use may decrease the destructive effects of methotrexate on testicular tissue of patients using this agent.

A "zero sample concentration approach": standardization of methods for the estimation of total antioxidant activity by the use of extrapolation to zero sample concentration. A novel standard. 1. ABTS cation radical scavenging

The study presents the general method of standardization of estimations of total antioxidant activity (TAA) by extrapolating parameters to zero sample concentration based on a pseudo-first-order kinetics model. To test its suitability, the method was applied to the ABTS cation radical scavenging assay, as the first choice. Two alternative methods of extrapolation were presented, via linear regression and numerical fitting to the dose-response profile. An extrapolation method gives the highest value of estimates, independent of sample concentration, and creates a new standard approach to the methods of TAA estimation. It is proposed to designate the modified index as "standard equivalent antioxidant capacity at zero" (SEAC0) or TEAC0 (for Trolox as standard). The examples of estimates for some foods and rat plasma are presented and compared with the literature method. The applicability of the extrapolation approach to the other TAA measurement methods is under evaluation.

Yolk testosterone reduces oxidative damages during postnatal development

Conditions experienced during early life can influence the development of an organism and several physiological traits, even in adulthood. An important factor is the level of oxidative stress experienced during early life. In birds, extra-genomic egg substances, such as the testosterone hormone, may exert a widespread influence over the offspring phenotype. Interestingly, testosterone can also upregulate the bioavailability of certain antioxidants but simultaneously increases the susceptibility to oxidative stress in adulthood. However, little is known about the effects of maternally derived yolk testosterone on oxidative stress in developing birds. Here, we investigated the role of yolk testosterone on oxidative stress of yellow-legged gull chicks during their early development by experimentally increasing yolk testosterone levels. Levels of antioxidants, reactive oxygen species and lipid oxidative damage were determined in plasma during nestlings' growth. Our results revealed that, contrary to control chicks, birds hatched from testosterone-treated eggs did not show an increase in the levels of oxidative damage during postnatal development. Moreover, the same birds showed a transient increase in plasma antioxidant levels. Our results suggest that yolk testosterone may shape the oxidative stress-resistance phenotype of the chicks during early development owing to an increase in antioxidant defences and repair processes.

Antimutagenic effects of lichen Pseudovernia furfuracea (L.) Zoph. extracts against the mutagenicity of aflatoxin B1 in vitro

The aim of this study was to investigate the effects of methanol, acetone, n-hexane and ether extracts obtained from Pseudovernia furfuracea on genotoxicity and total antioxidant capacity (TAC) in cultured human blood cells intoxicated with aflatoxin B 1 (AFB1). Sister chromatid exchange (SCE) and micronucleus (MN) tests were used for genotoxic influences estimation. In both the test systems, it was observed that P. furfuracea extracts suppressed the mutagenic effects of AFB1 due to the type of extracts added to the cultures. Furthermore, a significant reduction in plasma TAC was observed after AFB 1 treatment. Interestingly, the methanol and acetone extracts of the lichen recovered AFB1-induced TAC inhibition. The order of extracts of anti-genotoxicity efficacy against AFB1 was methanol, acetone, ether and n-hexane, respectively. In conclusion, P. furfuracea has been shown to modulate the adverse effects of AFB1 in human blood cells for the first time.

Oxidative stress and information content of black and yellow plumage coloration: an experiment with greenfinches

Carotenoid and melanin pigments in the plumage of birds are hypothesized to be sensitive to oxidative stress. We manipulated oxidative status of captive greenfinches (Carduelis chloris L.) by the administration of buthionine sulfoximine (BSO), a selective inhibitor of the synthesis of glutathione (GSH), an intracellular antioxidant. Half of the birds in the treated group, as well as in the control group, also received dietary carotenoid (lutein) supplementation. BSO treatment reduced erythrocyte GSH levels and caused oxidative damage as indicated by the increased concentration of plasma malondialdehyde (MDA), an end product of lipid peroxidation. BSO treatment also reduced the brightness (i.e. increased blackness) of the tips of tail feathers grown during the experiment. These results show that a low systemic GSH level is required for development of eumelanin plumage coloration and that such a low GSH level is also potentially dangerous for the organism. Carotenoid supplementation increased plasma carotenoid levels and chroma of the yellow parts of the feathers grown during the experiment. However, carotenoid supplementation did not reduce plasma MDA levels. Manipulation of GSH did not affect plasma carotenoids or carotenoid-based plumage coloration. These findings argue against the antioxidant function of lutein in vivo and carotenoid signaling of antioxidant status.

Assessment of total antioxidant capacity and the use of vitamin C in the treatment of non-smokers with chronic periodontitis

BACKGROUND

Several recent studies have indicated that total antioxidant capacity (TAOC) of plasma seems to be compromised in chronic periodontitis (ChP). The aim of this study is to investigate plasma TAOC in patients with ChP and to assess the effects of vitamin C as an adjunct to non-surgical periodontal treatment.

METHODS

The study population consisted of 60 subjects: 30 diagnosed with ChP and 30 matched controls. Furthermore, patients from the ChP group were randomly allocated into ChP1 (15 patients received non-surgical treatment with adjunctive dose of vitamin C) and ChP2 (15 patients received non-surgical periodontal treatment alone). Plasma TAOC levels were measured by an ABTS assay at baseline and 1 month post-therapy.

RESULTS

Plasma TAOC levels were significantly lower in ChP patients than controls (P <0.001). The periodontal therapy resulted in increasing plasma TAOC and improvements in clinical measures among both ChP1 and ChP2 groups (P <0.001). However, the adjunctive dose of vitamin C did not offer additional effect (P >0.05).

CONCLUSIONS

ChP is significantly associated with lower levels of plasma TAOC. The non-surgical periodontal therapy seems to reduce the oxidative stress during the periodontal inflammation. However, the use of adjunctive vitamin C still needs further investigation.

The genotoxic and oxidative damage potential of olanzapine in vitro

Olanzapine (OLZ) is an atypical antipsychotic drug and is commonly used for the treatment of schizophrenia and bipolar disorder (BD). However, recent reports indicated that this drug could exhibit cytotoxic effects on nervous and immune systems. To our knowledge, there is scarce data considering the genotoxic or oxidative damage potentials of OLZ on human lymphocyte culture system. Therefore, in this study, the genotoxic potential of OLZ (0 to 160 µM) have been evaluated in human whole blood cultures (WBCs) related to oxidative status. Sister-chromatid exchange (SCE) test was applied to estimate the DNA damage, and biochemical parameters (total antioxidant capacity [TAC] and total oxidative stress [TOS]) were examined to determine oxidative stress. Our results indicated that the tested antipsychotic drug did not induce SCEs in lymphocytes of treated cultures. However, the application of the highest OLZ concentration caused oxidative stress. It is concluded that the OLZ can be used safely, but it is necessary to consider the tissue damages that are likely to appear depending on the oxidative stress.

Indirect predator effects on clutch size and the cost of egg production

Predator-induced changes in physiology and behaviour may negatively affect a prey's birth rate. Evidence of such indirect predator effects on prey demography remains scarce in birds and mammals despite invertebrate and aquatic studies that suggest ignoring such effects risks profoundly underestimating the total impact of predators. We report the first experimental demonstration of indirect predator effects on the annual 'birth' rate resulting from negative effects on the size of subsequent clutches laid by birds. We manipulated the probability of nest predation and measured the size of subsequent clutches and multiple indices of the mother's physiological condition, while controlling for food availability, date and stage of breeding. Females subject to frequent experimental nest predation laid smaller subsequent clutches and were in poorer physiological condition, particularly regarding non-resource-based indices (e.g. oxidative stress and glucocorticoid mobilization) consistent with both a response to the threat of predation and an increased cost of egg production.

Beneficial effect of erdosteine on methotrexate-induced testicular toxicity in mice

Methotrexate is used to treat certain types of cancer of the breast, skin, head and neck, or lung. Methotrexate can cause serious or life-threatening side effects on liver, lungs, kidneys, and immune system. Methotrexate chemotherapy causes testicular damage in humans. The aim of this study was to investigate the possible protective role of erdosteine on testicular toxicity of methotrexate in mice. Twenty-six male mice were divided into four groups as follows: group 1, control; group 2, erdosteine-treated; group 3, methotrexate-treated; and group 4, methotrexate + erdosteine treated. On the first day of experiment, a single dose of methotrexate was intraperitoneally administered to groups 3 and 4, although a daily single dose of erdosteine was orally administered to group 2 and 4 for 7 days. At the end of the experiment, the testes of the animals were removed and weighed. The levels of total antioxidant capacity and total oxidative stress, and myeloperoxidase activity in the methotrexate group were higher than the control group (p<0.05). Lipid peroxidation levels were not changed in methotrexate group compared with control group. In conclusion, erdosteine could effectively protect the testes in methotrexate-induced toxicity.

Oxidative status and lipid profile in metabolic syndrome: gender differences

BACKGROUND

Metabolic syndrome is associated with cardiovascular disease and oxidative stress. The aim of this study was to investigate the differences of novel oxidative stress parameters and lipid profiles in men and women with metabolic syndrome.

METHODS

The study population included 88 patients with metabolic syndrome, consisting of 48 postmenauposal women (group I) and 40 men (group II). Premenauposal women were excluded. Plasma levels of total antioxidant status (TAS) and total oxidative status (TOS) were determined by using the Erel automated measurement method, and oxidative stress index (OSI) was calculated. To perform the calculation, the resulting unit of TAS, mmol Trolox equivalent/L, was converted to micromol equivalent/L and the OSI value was calculated as: OSI = [(TOS, micromol/L)/(TAS, mmol Trolox equivalent/L) x 100]. The Student t-test, Mann-Whitney-U test, and chi-squared test were used for statistical analysis; the Pearson correlation coefficient and Spearman rank test were used for correlation analysis. P < or = 0.05 was considered to be statistically significant.

RESULTS

Both women and men had similar properties regarding demographic characteristics and biochemical work up. Group II had significantly lower levels of antioxidant levels of TAS and lower levels of TOS and OSI compared with group I (P = 0.0001, P = 0.0035, and P = 0,0001). Apolipoprotein A (ApoA) levels were significantly higher in group I compared with group II.

CONCLUSIONS

Our findings indicate that women with metabolic syndrome have a better antioxidant status and higher ApoA levels compared with men. Our findings suggest the existence of a higher oxidative stress index in men with metabolic syndrome. Considering the higher risk of atherosclerosis associated with men, these novel oxidative stress parameters may be valuable in the evaluation of patients with metabolic sydrome.

Hematological condition indexes in greenfinches: effects of captivity and diurnal variation

Ecophysiological research aiming at explaining the causes and consequences of variation in individual condition, health state, and allostasis is traditionally performed on captive animals under controlled laboratory conditions. The question about how captivity per se affects studied parameters is therefore of central importance for generalizing the information gained from such studies. We addressed this question by comparing various indexes of physiological condition of wintering greenfinches sampled in the wild and kept in captivity for different time periods. Bringing wild greenfinches into captivity did not result in systematic alteration in nine of 12 physiological parameters studied. Captive birds had consistently lower plasma carotenoid and uric acid levels than wild ones. Variation in differential leukocyte counts did not reveal any signs of elevated stress of birds kept in captivity. These results indicate that for a number of physiological parameters, information obtained from captive animals can be generalized to natural situations. Variance in traits most closely related to physical exercise capacity (body mass and hematocrit) were much lower in the wild than in captivity. These findings suggest that under harsh environmental conditions experienced by wild birds (i.e., predation threat, scarce resources), traits such as hematocrit and body mass are fine tuned by physiological trade-offs.