Pakize Dogan

Oxidative enzymes of polymorphonuclear leucocytes and plasma fibrinogen, ceruloplasmin, and copper levels in Behcet's disease

This study was performed to investigate the antioxidant mechanisms of polymorphonuclear leucocytes (PMN) in active stage of Behçets Disease. PMN activities of myeloperoxidase (p < 0.02), superoxide dismutase (p < 0.001), catalase (p < 0.005), and glutathione peroxidase (p < 0.005) were significantly lower in the patients: the NADPH oxidase activity was significantly higher (p < 0.001) than those in controls. The plasma levels of ceruloplasmin (Cp), fibrinogen, and copper (Cu) were also significantly higher in the patients group (p < 0.001). Significant and positive correlations were found between the glutathione peroxidase and catalase activities (p < 0.001) and also between the plasma Cp and Cu levels (p < 0.001) in the patients group. However, no correlation was observed among the other enzyme activities. In the control group, a significantly positive correlation was present only between the plasma ceruloplasmin and Cu levels (p < 0.001). It was concluded that (impaired PMN functions) decreased enzyme activities in the antioxidant system and increased levels of oxygen free radicals may play a role in tissue damage in Behçets disease.

The effect of vitamin E on ipsilateral and contralateral testis following unilateral testicular torsion in rats.

An experimental study was conducted to investigate the role of lipid peroxidation in ipsilateral and contralateral testicular reperfusion injury following unilateral testicular torsion (TT) and the effect of vitamin E in the management of this injury. Fifty adult male Sprague-Dawley rats were divided into five equal groups. Bilateral orchiectomy was performed immediately in group 1, and 3 h after unilateral TT in group 2. In group 3, both testes were harvested 3 h after a sham operation. In groups 4 and 5, unilateral TT, detorsion after 3 h and bilateral orchiectomy after 6 h were performed. Vitamin E was given before detorsion in group 4 and after detorsion in group 5. The levels of malondialdehyde (MDA) were meas-ured as an index of lipid peroxidation in all testes. There were no significant differences between right and left testes within groups or between right or left testicular MDA values in different groups. The results suggest that lipid peroxidation does not play an important role in ipsilateral and contralateral testicular injury following unilateral TT and that vitamin E given before or after detorsion of testes is not useful in preventing testicular reperfusion injury.

A model of hypoxia-induced necrotizing enterocolitis: The role of distension

BACKGROUND/PURPOSE This study was performed to investigate additional effects of intestinal distension in the damage to the gut caused by hypoxia-reperfusion. METHODS Five groups each consisting of ten 1-day-old Wistar albino rat pups were studied; Group 1, hypoxia-reoxygenation; Group 2, hypoxia-reoxygenation and distension; Group 3, distension and hypoxia-reoxygenation; Group 4, distension; and Group 5, control. Hypoxia was induced by placing the rat pups in a 100% carbon dioxide chamber for 5 minutes. After the hypoxia, the pups were exposed to 100% oxygen for reoxygenation for 5 minutes. The intestinal distension was carried out with a fine 21-gauge SILASTIC cannula via rectal route. The rats were killed on the third day, and all the intestine were harvested from duodenum to sigmoid colon. Malondialdehyde (MDA) levels were determined as an index of lipid peroxidation related to free radical reaction in the intestine. The histopathologic investigation was carried out by light microscopy in a blinded fashion. RESULTS The MDA levels of Group 3 animals were significantly higher than those in Group 1, 4, and the control group (P < .05). The MDA level of Group 2 did not differ significantly from that of the Group 3 (P > .05). All MDA levels of the study groups also were significantly higher than the control group (P < .05). CONCLUSION The results demonstrated that intestinal distension increased the damaging effects of hypoxia-reoxygenation in the gut.

Oxidative stress in hemodialyzed patients and the long-term effects of dialyzer reuse practice.

OBJECTIVES To investigate the existence of an altered oxidant/ antioxidant balance in patients on regular hemodialysis treatment (RHT) and whether there is any effect of dialyzer reuse on oxidative damage and antioxidative mechanism. DESIGN AND METHODS Malondialdehyde (MDA) levels and glutathione peroxidase (GPx) activities in both plasma and erythrocytes, plasma selenium (Se) levels, and erythrocyte superoxide dismutase (SOD) activities of RHT patients were determined at the beginning and end of 4-month reuse period. RESULTS When compared to healthy controls, both plasma and erythrocyte MDA levels were found to be significantly higher in RHT patients before the dialyzer reuse practice; whereas both plasma and erythrocyte GPx activities, erythrocyte SOD activity, and also plasma Se levels were lower in the same patient group than those of controls. When statistical comparison was made on RHT patients between before and after the reuse period, the decreases in MDA levels but increases in the enzyme activities and also an increase in plasma Se levels were observed after the reuse period. However, erythrocyte SOD activities and plasma Se levels measured after the reuse period were not found to be statistically different from the control values; MDA levels still remained elevated above the control values, and GPx activities were not attained to those of controls, after the reuse practice. In addition, positive correlations were found between activities of erythrocyte SOD and GPx enzymes, between GPx and Se levels and negative correlations between the activities of both enzymes and MDA levels in erythrocytes of patients on RHT. CONCLUSION These findings may indicate that dialyzer reuse may provide, at least partly, an improvement on oxidative stress in patients on RHT.

Plasma and erythrocyte lipid peroxide levels in workers with occupational exposure to lead

The plasma and erythrocyte lipid peroxide levels were measured in a group of male subjects occupationally exposed to lead for an average period of 17 yr, and compared to those from an age-matched control group living in the same city in a similar socioeconomical environment.The blood lead and plasma zinc levels were measured by atomic absorption spectroscopy. The plasma and erythrocyte lipid peroxide levels were established by the malondialdehyde determination method. Significant differences were found in the blood lead levels in lead-exposed workers, 15.00±10.15 µg/dL as compared to controls, 2.37±0.89 µg/dL. The plasma (2.67±0.69 µM) and erythrocyte (27.53±6.28 nmol/g Hb) lipid peroxide levels in workers with occupational exposure to lead were significantly higher than controls, 1.23±0.61 µM and 14.35±2.08 nmol/g Hb, respectively. There were no significant differences of the zinc levels in both groups.The blood lead levels had a statistically significant positive correlation with age and with duration of exposure in both groups, but showed no relationship to the corresponding blood zinc levels. The results presented in this study indicate that the increase of plasma and erythrocyte lipid peroxide levels in workers exposed to lead may be related to the lead concentration, age and duration of exposure.

The effect of acute ligation of the rabbit appendix on antioxidant enzymes

The role of oxygen free radicals (OFR) in the pathogenesis of many diseases is known. This experimental study was planned to investigate the role of OFR in acute abdominal inflammation. In this study, 20 adult rabbits were used. They were divided into two groups with 10 rabbits in each. In the study group, blood samples were taken from peripheral and mesenteric veins and then their appendices were ligated; after 24 h, blood samples were taken again and the appendices were resected. The same procedures were carried out in the control group, except for ligation of the appendices. Superoxide dismutase, catalase and glutathione peroxidase (GPX) activities were measured in all blood samples. The activities of catalase and GPX were increased postoperatively in peripheral and mesenteric blood samples in the experimental group. The catalase activity was increased in the control group. These results suggest that OFR increased sufficiently to activate the enzymatic defense system in acute appendicitis.

MAO-B activity in depression and anxiety disorders

Monoamine oxidase (MAO) is a mitochondrial enzyme responsible for the oxidative deamination of catecholamines and indolamines (Alexopoulos et al 1984). Plate!ets contain only MAO-B, whereas human brain contains both MAO-A and MAO-B (Po~,rier et al 1987). The kinetics of platelet MAO-B are believed to be similar to central turnover of monoamines (Georgotas et al 1986), but Young and colleagues (1986) found no connection between platelet and brain MAO-B. Nevertheless, this controversial area has been implicated in attempts to identify a biological marker tbr the evaluation of the size or capacity of the central serotonin system (Hailman et al 1990). In this study we examined platetet MAO-B activity as a biological marker tbr depressive and anxiety disorders, giving par.icular attention to its relation to age of onset.