Orhan Canbolat

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.

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.

Antioxidant interferences in superoxide dismutase activity methods using superoxide radical as substrate.

Sir, In several methods for the measurement of the superoxide dismutase (SOD; E.C 1.15.1.1) activity, superoxide radical (O2• -) produced from various sources such as the xanthin/xanthine oxidase system, pyrogallol oxidation etc. has been used as the substrate (1–4). In general, SOD activity is measured on the basis of competition between O2• dismutation by this enzyme or by an oxidising substance such as nitroblue tetrazolium salt (NBT), nicotinamide adenine dinucleotide (NAD) etc. Accordingly, when SOD activity is high, reduction rate of the oxidising substance is low and vice versa. In these methods, there is however interference from non-enzymatic antioxidants, which mainly results from cellular components with antioxidant capacity. Some of these substances, such as hemoglobin, transferrin, albumin, ceruloplasmin and haptoglobin, exert their antioxidant activities by binding metal ions which play a part in free radical production. Others, such as uric acid and vitamins A, C and E, mainly act as chainbreaking antioxidants. Due to this fact, it is not possible to carry out a valid measurement of activity without removing these non-enzymatic antioxidant substances from the medium. Although some researchers use chloroform/ethanol extraction to eliminate these substances, this procedure cannot remove all of them; hydrophilic antioxidants remain in the alcohol/water phase. Therefore, in the present methods, total (enzymatic plus non-enzymatic) superoxide radical scavenger activity (TSSA) instead of SOD activity is measured. We have used human erythrocytes and, rabbit liver and lung to assess this interference. First, we measured SOD activites in erythrocyte hemolyzates and in lung and liver by using the method described previously (5, 6). Second, activity measurements were made in trichloroacetic acid (TCA)-treated fractions, which were prepared by treating part of the sample with 20 % (w/v) TCA solution and centrifuging at 5000 xg for 30 min. We observed that TCA-treatment causes no meaningful changes in the pH of the final assay mixture (pH = 10.5 in untreated assay and 10.2 in TCAtreated assay). Activity assays were performed in the supernatant fraction. One unit of SOD activity was defined as the amount of protein causing 50% inhibition in NBT reduction rate. Results are given in Table 1. As shown in the table, a significant amount of SOD activity still exists in the supernatant fluids after TCAtreatment, which have removed all enzyme. There must therefore be other, non-enzymatic, factors which remove O2• from the reaction medium. Therefore, activity values measured by the present methods should be regarded as TSSA rather than enzyme activity and SOD activity should be calculated from the equation below.

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.

Serum adenosine deaminase and total superoxide dismutase activities before and after surgical removal of cancerous laryngeal tissue

In this study, pre- and post-operative serum activities of adenosine deaminase (ADA) and total superoxide dismutase (SOD) enzymes were measured in patients with squamous cell laryngeal cancer. Activities of both enzymes were found to be higher in cancerous patients compared to the controls. No significant differences were found however between pre- and post-operative values for both enzymes in the patient group. It has been suggested that ADA and SOD enzymes leak from the cancerous laryngeal tissues into the blood stream. The absence of differences between pre- and post-operative serum enzyme activities has two possible explanations: Firstly, removal of previously released enzymes from the blood stream takes a much longer period than one month; and secondly, cancerous laryngeal tissue is not the only source of the enzymes mentioned even after removal of cancerous tissue by surgical operation, other sources such as adjacent tissues and/or metastatic tissues etc, still release these enzymes into the blood stream.

ACTIVITIES OF SUPEROXIDE DISMUTASE AND GLUTATHIONE PEROXIDASE ENZYMES IN CANCEROUS AND NON-CANCEROUS HUMAN KIDNEY TISSUES

The activities of superoxide dismutases (total, cytoplasmic and mitochondrial) and glutathione peroxidase were measured in 10 cancerous and 10 non-cancerous adjacent human kidney tissues. Total (T-SOD) and cytoplasmic (Cu, Zn-SOD) superoxide dismutase and glutathione peroxidase (GSH-Px) activities were found lower in cancerous tissues compared with those of non-cancerous ones. However, no difference was found between the mitochondrial (Mn-SOD) superoxide dismutase activities of the tissues. Similarly, no differences were observed between the enzyme activity values of the tissues at stages I–II and III–IV renal cancer. In correlation analysis the positive relation found between Cu, Zn-SOD and GSH-Px enzymes in the non-cancerous tissues was found to be absent in the cancerous ones.The results suggest that enzymatic free radical defense mechanism is significantly reduced in the cancerous human kidney tissues due to depressed Cu, Zn-SOD and GSH-Px activities.

The Effects of Gentamicin on the Activities of Glutathione Peroxidase and Superoxide Dismutase Enzymes and Malondialdehyde Levels in Heart Tissues of Guinea Pigs

In this study, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and malondialdehyde (MDA) levels were measured in heart tissues from guinea pigs treated with gentamicin and gentamicin plus vitamin E combination. Mean values were compared with those of the controls treated with only physiological saline solution. The activities of SOD and GSH-Px were found to be lower and the MDA level higher in the hearts from gentamicin-treated animals compared with those of the controls. In the gentamicin plus vitamin E group, however, tissue SOD activity was found to be increased and MDA level decreased significantly relative to the gentamicin group. GSH-Px activity was lowest in this group. Results suggest that gentamicin suppresses SOD and GSH-Px activities in heart tissue, thereby making the tissue more vulnerable to oxidative stress and peroxidative attacks, an important indicator of which is increased MDA level in the heart tissues from gentamicin-treated guinea pigs. This effect might be deleterious when gentamicin is used after cardiac surgery since a potential risk of free radical injury exists in the heart tissue during and/or after cardiac surgery owing to ischaemia and reperfusion processes, and, possibly, in the management of the patients with certain types of heart disease. Our results showed that vitamin E given concomitantly with gentamicin could protect the heart tissue against free radical injury.

Effects of repeated desflurane and sevoflurane anesthesia on enzymatic free radical scavanger system

Background: To investigate the possible effects of repeated sevoflurane and desflurane anesthesia on hepatocellular system by evaluating the free radical metabolism, hepatocellular enzymes and histopatholgical changes in rats. Methods: Four groups of animals were studied. Sevoflurane 2% (v/v) and desflurane 6% (v/v) in air/O2 were administered to animals in group II (n = 9) and III (n = 9) respectively. 100% (v/v) O2 was administered in group IV (n = 9). Administration was done for 60 minutes over 3 days. Nine animals were allocated to control group (group I), superoxide dismutase (SOD), catalase (CAT), glutathion peroxidase (GSH-Px), glutathione-s-transferase (GST) and thiobarbituric acid reactive substances (TBARS) were studied. Also electron microscopy was performed. Results: Catalase, SOD, GSH-Px, GST activities and TBARS levels were significantly higher in groups II and III than in group I (p < 0.05). All parameters were significantly higher in groups II versus group IV (p < 0.05). On the other hand, SOD, GSH-Px and GST activities were significantly elevated in group III than IV, but CAT activity and TBARS levels were not significantly. Catalase, SOD, GSH-Px, GST but not TBARS levels were significantly higher in groups II and III than in group IV (p < 0.05). TBARS levels were higher in group III than in group IV, but this elevation was not statistically significant. CAT, SOD and GSH-Px activities were significantly higher in groups II than in group III (p < 0.05). Conclusion: Although electron microscopy findings were similar for group II and III, we can conclude that sevoflurane might cause more cellular damage than desflurane by causing higher activation of free radical metabolising enzymes.