Mustafa Kavutcu

Role of Oxidative Stress in Intrauterine Growth Restriction

Aims: The objectives of this study were to determine the role of oxidative stress in intrauterine growth restriction (IUGR) and to investigate the possible molecular mechanism(s) leading to oxidant stress in IUGR. Methods: Parameters of the oxidative and antioxidant system were evaluated in maternal plasma, umbilical cord blood, and placental tissue of pregnant women with IUGR fetuses. The same samples were obtained from women with normal pregnancies and were evaluated. Results: The results of this study indicate that while the levels of malondialdehyde (MDA) and xanthine oxidase (XO) were higher in maternal plasma, umbilical cord plasma, and placental tissues of the patients with IUGR when compared to the control group [MDA: 142.8 ± 18.0 vs. 86.4 ± 22.5 nmol/ml, 151.6 ± 25.8 vs. 93.3 ± 7.4 nmol/ml, and 0.72 ± 0.19 vs. 0.42 ± 0.09 nmol/mg protein, respectively (for all p < 0.0005); XO: 1.251 ± 0.674 vs. 0.20 ± 0.019 mIU/ml (p < 0.0005), 1.97 ± 0.73 vs. 0.237 ± 0.143 mIU/ml (p < 0.0005), and 0.023 ± 0.0012 vs. 0.012 ± 0.004 mIU/ml (p < 0.025), respectively], the levels of antioxidant potential were identified to be lower in maternal plasma, umbilical cord plasma, and placental tissues of the patients with IUGR: 63.3 ± 11.9 vs. 198.0 ± 31.9 U/ml (p < 0.0005), 32.6 ± 3.7 vs. 206.5 ± 27.1 U/ml (p < 0.0005), and 0.56 ± 0.23 vs. 1.16 ± 0.29 U/ml (p < 0.0005), respectively. On the other hand, the activities of adenosine deaminase of the IUGR patients were higher than those of the control group in maternal plasma (204.8 ± 103.5 vs. 115.6 ± 31.8 U/l, p < 0.01) and umbilical cord blood samples (584.2 ± 285.2 vs. 147.9 ± 44.8 U/l, p < 0.0005) which may suggest that oxidative stress has a role in IUGR. Moreover, an increased superoxide dismutase activity in maternal plasma (128.2 ± 37.4 vs. 88.8 ± 16.6 U/ml, p < 0.005) and cord blood (162.1 ± 37.0 vs. 116.6 ± 20.7 U/ml, p < 0.005) and an increased glutathione peroxidase activity in maternal plasma (1.83 ± 0.26 vs. 1.47 ± 0.31 IU/ml, p < 0.01) and placental tissue (0.007 ± 0.0015 vs. 0.003 ± 0.0012 IU/ml, p < 0.0005) were detected, while decreased catalase activities in cord blood (23,717 ± 3,538 vs. 16,397 ± 2,771 IU/ml, p < 0.0005) and placental tissue (47.2 ± 17.2 vs. 70.7 ± 11.3 IU/ml, p < 0.005) were identified in IUGR groups. Conclusions: In the light of the results of this study, it can be stated that the oxidative stress increases in patients with IUGR. Providing high-risk patients with an antioxidant may be useful in the prevention or treatment of IUGR, although it is a condition with no certain treatment outcome.

ACTIVITIES OF TOTAL, CYTOPLASMIC, AND MITOCHONDRIAL SUPEROXIDE DISMUTASE ENZYMES IN SERA AND PLEURAL FLUIDS FROM PATIENTS WITH LUNG CANCER

In this study, total cytoplasmic (Cu, Zn‐SOD) and mitochondrial (Mn‐SOD) superoxide dismutase activities were measured in sera and pleural fluids from patients with squamous cell carcinoma of the lung. The results were compared with those of control subjects and those of patients with tuberculosis and chronic heart failure. Serum activities were found higher in all patient groups compared to control group. Highest values were however in tuberculosis group. In the correlation analysis, meaningful intra‐ and inter‐correlations were established between enzyme activities in the samples.

Reduced Erythrocyte Defense Mechanisms against Free Radical Toxicity in Patients with Chronic Renal Failure

In this study, activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) enzymes were determined in the erythrocytes from patients with chronic renal failure (CRF) and from healthy subjects. In the conservative drug management group and intermittent ambulatory peritoneal dialysis group, CAT activity was lower than in the control group. However, SOD and GSH-Px activities of these groups were not statistically different from the control values. In the continuous ambulatory peritoneal dialysis group and the hemodialysis group, SOD, GSH-Px and CAT activities were lower than control values. In the patient groups, correlation coefficients between the enzyme activities were also found to be different from the control values. Results suggested that enzymatic antioxidant defense mechanisms were suppressed in the erythrocytes from the patients with CRF, in particular in the erythrocytes from those who were under hemodialysis and continuous ambulatory peritoneal dialysis management. It is proposed that reduced antioxidant defense mechanisms in the erythrocytes is one of the important factors leading to peroxidation in the membrane lipid structure of the erythrocytes and thereby to hemolysis and anemia in the patients with CRF.

Reduced enzymatic antioxidant defense mechanism in kidney tissues from gentamicin-treated guinea pigs : effects of vitamins E and C

In this study, the activities of major enzymes participating in free radical metabolism (xanthine oxidase, XO; Cu,Zn and Mn superoxide dismutases, SOD; glutathione peroxidase, GSH-Px; catalase, CAT) were measured in kidney tissues from guinea pigs treated with gentamicin alone (200 mg/kg/day), gentamicin plus vitamin C (600 mg/kg/day), gentamicin plus vitamin E (400 mg/kg/day), and gentamicin plus vitamins C and E together for 10 days, and from animals treated with physiological saline solution alone during this period. We found no significant differences between control and gentamicin groups with respect to XO and Cu,Zn-SOD activities. However, the activities of Mn-SOD, GSH-Px, and CAT were found to be significantly depressed in the gentamicin-treated group relative to controls. In the gentamicin plus vitamin C group, the renal tissue Mn-SOD activity was found to be higher as compared with control and gentamicin groups. In this group, XO, GSH-Px and CAT activities were also higher than in the gentamicin-treated group, but no statistically significant differences existed between the values of this group and controls. Similar results were also observed in the gentamicin plus vitamin E group for Mn-SOD, GSH-Px, CAT, and XO. In this group, the Cu,Zn-SOD activity was found to be decreased as compared with control and gentamicin groups. In the gentamicin plus vitamins C and E group, the Cu,Zn-SOD activity was found to be decreased, the XO activity to be unchanged, and Mn-SOD, GSH-Px, and CAT activities to be increased as compared with the gentamicin and control groups. The results suggest that the enzymatic antioxidant defense system was significantly disturbed because of the suppressed activities of Mn-SOD, GSH-Px, and CAT in the kidney tissues from animals treated with gentamicin. However, vitamins C and E given concurrently with gentamicin completely abrogated this enzymatic suppression.

Oxidative imbalance in child and adolescent patients with attention-deficit/hyperactivity disorder

Various psychological, social, genetic, and biochemical factors are thought to be involved in the aetiology of attention-deficit/hyperactivity disorder (ADHD). However, few studies have evaluated the biochemical basis of ADHD. In the present study, we evaluate whether levels of nitric oxide pool (NO+NO(2)(-)) and malondialdehyde (MDA) oxidants as well as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) antioxidant enzyme activities are associated with ADHD. The sample population consisted of thirty-five child or adolescent patients diagnosed with ADHD according to DSM-IV-TR criteria. Thirty-five healthy subjects also were included in the study as controls. Venous blood samples were collected, and NO pool and MDA levels as well as SOD, GSH-Px, and CAT activities were measured. NO and MDA levels of the patients were significantly higher than the controls. GSH-Px activities of the patients were significantly lower than the controls. CAT activities of the patients were higher than the controls; however, the difference was not statistically significant. There were no significant differences in SOD activity between the patient and control groups. Remarkably high levels of NO pool and MDA oxidants as well as low GSH-Px activities suggest an oxidative imbalance in paediatric patients with ADHD. CAT activities may be increased in response to increased oxidant levels.

Activities of adenosine deaminase, 5'-nucleotidase, guanase, and cytidine deaminase enzymes in cancerous and non-cancerous human breast tissues.

We measured activities of some DNA turnover enzymes in 9 breast tissues with stage II cancer, 6 breast tissues with stage IIIa cancer, and 9 non-cancerous adjacent breast tissues from the same patients with stage II cancer. We found higher Adenosine Deaminase (ADA) and 5′-Nucleotidase (5′NT) and lower Guanase (GUA) activities in the cancerous tissues compared with the non-cancerous ones. No meaningful differences were however found between Cytidine Deaminase (CD) activities. Regarding the correlation analysis, positive correlations were established between ADA and 5′NT activities of the cancerous tissues (r = 0.45 for the tissues with stage II and r = 0.60 for the tissues with stage IIIa cancer). No meaningful correlations were however found between other enzyme activities. Relating to activity ratios, no meaningful differences were found between ADA/5′NT values in the tissues. GUA/CD ratios were however lower and the other ratios higher in the cancerous tissues.Results indicated that ADA and 5′NT activities increased and GUA activity decreased in the cancerous breast tissues but CD activities did not change in the tissues affected. It has been suggested that increased ADA and 5′NT together with decreased GUA activities might be a physiologic attempt of the cancer cells to provide more substrates needed by cancer cells to accelerate the salvage pathway activity. Furthermore, high ADA activity might also play part in the detoxication process of high amounts of toxic adenosine and deoxyadenosine substrates produced from accelerated purine metabolism in the cancerous tissues.

Changes in oxidative stress and cellular immunity serum markers in attention-deficit/hyperactivity disorder

Aims:  Attention‐deficit/hyperactivity disorder (ADHD) is a developmental disorder with an etiopathogeny not fully understood. According to the prevailing view, the main factors contributing to the disorder are prefrontal dopamine deficiency and central dopaminergic dysfunction, but the factors/mechanisms involved in the brain dysfunction and its consequences are not well known. We suggest that changes in oxidative metabolism and cellular immunity may be involved. In this study, we aimed to investigate whether there are associations between ADHD and changes in serum levels of nitric oxide synthase (NOS), xanthine oxidase (XO), glutathione S‐transferase (GST) and paraoxonase‐1 (PON‐1) activities, which are important markers of oxidative stress, and adenosine deaminase (ADA) activity, marker of cellular immunity.

Halothane hepatotoxicity and hepatic free radical metabolism in guinea pigs; the effects of vitamin E

PurposeThe aim of this study was to investigate the relation between halothane hepatotoxicity and hepatic free radical metabolism and to establish a possible protective role of vitamin E against halothane hepatotoxicity.MethodsTwenty-eight guinea pigs were used in the experiments. Halothane (1.5% v/v) in oxygen (100%) was given to the animals for 90 min over three days. Livers from animals were then taken and prepared for the assays. In the enzymatic study, Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities were measured. As a peroxidation index, the malondialdehyde (MDA) concentration was determined. Also, electron spin resonance (ESR) analysis and electron microscopy (EM) were performed. Results: Superoxide dismutase (1168.3 ± 78.2 U · mg−1) and glutathione peroxidase (14.9 ± 6.2 mIU · mg−1) activities were decreased, but catalase activity (1260.0 ± 250.6 lU · mg−1) and malondialdehyde concentration (11.5 ± 1.8 ppb) were increased in liver tissues exposed to halothane compared with control values (1382.2 ± 91.8 U · mg−1 for SOD, 27.8 ± 5.2 mIU · mg−1 for GSH-Px, 840.2 ± 252.4 IU · mg−1 for CAT and 10.0 ± 1.0 ppb for MDA). Electron spin resonance analysis revealed a peak of CF3 CHCl radical in the exposed tissue. Electron microscopy indicated ultrastructural changes in the hepatic cells of both halothane groups with and without vitamin E treatment.ConclusionHalothane causes impairment in the hepatic antioxidant defense system and accelerates peroxidation reactions. As a result, some ultrastructural changes in hepatic tissues occur due to halothane treatment. Although vitamin E prevents peroxidative damage, it does not ameliorate ultrastructural changes caused by halothane treatment. This shows that halothane toxicity results not only from impaired hepatic antioxidant defense system but also from other, unknown causes.RésuméObjectifCette étude visait à examiner la relation possible entre l’hépatotoxicité à l’halothane et le métabolisme des radicaux libres et à vérifier si la vitamine E protège contre l’hépatotoxicité à, l’halothane.MéthodesVingt-huit cobayes ont été utilisés. De l’halothane (15% v/v) en oxygène (100%) a été administré aux animaux pendant 90 min sur une période de trois jours. Les foies ont alors été prélevés et préparés pour fin d’analyse. Pour l’étude enzymatique, l’activité de la superoxyde dismutase (SOD), de la glutathione peroxydase (GSH-Px) et de la catalase (CAT) a été mesurée. En tant qu ’indice de la peroxydation, la concentration de la malondialdéhyde (MDA) a été déterminée. En outre, on a procédé à des examens à la résonance paramagnétique électronique (Electronic spin resonance: ESR) et à la microscopie électronique (EM).RésultatsL’activité de la superoxyde dismutase (1168,3 ±78,2 U · mg−1) et de la glutathione peroxydase (14,9 ± 6,2 UI · mg−1) a diminué, mais celle de la catalase (1260,0 ± 250,6 Ul · mg−1) ainsi que la concentration de ta malondialdéhyde (11,5 ± 1,8 ppb) ont augmenté dans le tissus hépatique exposé à l’halothane comparativement aux valeurs de contrôle (1382,2 ± 91,8U · mg−1 pour SOD, 27,8 ± 5.2 mUI · mg−1 pour SGH-px, 840 ± 252,4 UI · mg−1 pour CAT et 10,0 ± 1,0 ppb pour MDA). La résonance paramagnétique a révélé un pic de radical CF3CHCl dans les tissus exposés. La microscopie électronique a montré des changements ultrastructuraux dans les cellules hépatiques chez les deux groupes halothane traités ou non à la vitamine E.ConclusionL’halothane provoque une altération du système de défense hépatique antioxydant et accélère les réactions de peroxydation. Il en résulte des changements ultrastructuraux des tissus hépatiques produits par l’exposition à l’halothane. Bien qu’elle prévienne le dommage peroxydatif, la vitamine E n’atténue pas les changements ultrastucturaux produits par l’exposition à l’halothane. Ceci montre que la toxicité à l’halothane résulte non seulement de l’altération du système de défense antioxydant mais aussi d’autres causes non déterminées.

Effects of isoflurane on nitric oxide metabolism and oxidant status of guinea pig myocardium

Background: Volatile anesthetics (VAs) have been shown to enhance myocardial recovery during reperfusion, the mechanism of which has not been clarified yet. It has been supposed that this effect of VAs may appear through antioxidative mechanisms.

STOBADINE PROTECTS RAT KIDNEY AGAINST ISCHAEMIA/REPERFUSION INJURY

1 Ischaemia–reperfusion (I/R) injury, one of the main causes of acute renal failure, still needs satisfactory treatment for routine clinical application. Stobadine, a novel synthetic pyridoindole anti‐oxidant, has the ability to reduce tissue injury induced by mechanisms involving reactive oxygen species during I/R. The aim of the present study was to determine the effects of stobadine on renal I/R injury. 2 Forty male Wistar rats were randomly divided into four groups as follows: sham, I/R, stobadine treated and I/R + stobadine treated. Stobadine (2 mg/kg, i.v.) was given intravenously to two groups of rats. The stobadine‐treated group was treated with stobadine following sham operation before the abdominal wall was closed, whereas the I/R + stobadine group received stobadine at the beginning of reperfusion. Renal I/R was achieved by occluding the renal arteries bilaterally for 40 min, followed by 6 h reperfusion. Immediately thereafter, blood was drawn and tissue samples were harvested to assess: (i) serum levels of blood urea nitrogen and creatinine; (ii) serum and/or tissue levels of malondialdehyde (MDA), glutathione (GSH), glucose 6‐phosphate dehydrogenase (G‐6PD), 6‐phosphogluconate dehydrogenase (6‐PGD), glutathione reductase (GR) and glutathione peroxidase (GPx); (iii) renal morphology; and (iv) immunohistochemical staining for P‐selectin. 3 Stobadine was able to significantly attenuate the renal dysfunction as a result of renal I/R injury. Iscahemia–reperfusion resulted in a significant increase in serum and kidney MDA levels and a decrease in serum and kidney GSH. Stobadine treatment at the beginning of reperfusion attenuated both the increased MDA levels and decreased GSH secondary to I/R injury. In addition, the decreased G‐6PD activity observed after I/R was significantly attenuated by stobadine treatment. Stobadine did not alter 6‐PGD activity after I/R. Neither GR nor GPx activity was significantly changed in the I/R alone or the I/R + stobadine groups compared with the sham group. In addition, stobadine decreased the morphological deterioration and high P‐selectin immunoreactivity secondary to renal I/R injury. 4 A pyridoindole anti‐oxidant, stobadine exerts a renal protective effect in renal I/R injury, which is probably due to its radical‐scavenging and anti‐oxidant activities.