The effects of fasting on blood antioxidant potential and malondialdehyde levels.
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Antioxidants↗
Biomedical subjects
I Durak
Publications and source records attributed to I Durak.
Activities of DNA turnover and free radical metabolizing enzymes in cancerous human prostate tissue.
Activities of adenosine deaminase (ADA), 5'nucleotidase (5'NT), xanthine oxidase (XO), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) and levels of thiobarbituric acid reagent substances (TBARS) were measured in 10 cancerous and 10 noncancerous human prostate tissues. Decreased activities of DNA turnover enzymes (ADA and 5'NT), increased activities of GSH-Px and CAT, and unchanged activities of SOD and XO were observed in cancerous prostate tissues compared with those of noncancerous ones. TBARS levels were found to be higher in cancerous tissues than noncancerous ones. In correlation analysis, mostly positive correlations were established between enzyme activities of the cancerous tissues, whereas no meaningful correlations were found between enzyme activities of the noncancerous tissues except for a positive correlation between XO and SOD. The results indicate that the activities of DNA turnover enzymes were reduced, which was possibly an attempt to lower the rate of purine catabolism, and the activities of GSH-Px and CAT enzymes were increased, probably in response to increased free radical stress occurring in cancerous prostate tissues. Increased concentrations of TBARS suggested oxidant stress and thus accelerated peroxidative reactions in the cancerous tissues, even though antioxidant defense mechanisms were activated. These findings suggest that enzymatic antioxidant systems of cancerous prostate tissues cannot sufficiently eliminate oxidant factors and prevent cellular peroxidative reactions occurring during the carcinogenic process.
5'-Nucleotidase↗
Enzymatic antioxidant defence mechanism in rat intestinal tissue is changed after ischemia-reperfusion. Effects of an allopurinol plus antioxidant combination.
OBJECTIVES: To establish the antioxidant status of rat intestinal tissues after ischemia-reperfusion and to determine if pretreatment with an allopurinol and antioxidant vitamin combination gives any protection against mucosal injury. EXPERIMENTAL ANIMALS: Twenty rats were divided into 4 groups of 5 animals each. METHODS: Group 1 (control) rats were not subjected to ischemia-reperfusion and received no allopurinol plus vitamin combination; group 2 rats received vitamins C (200 mg/kg) and E (100 mg/kg) and allopurinol (50 mg/kg) combination daily for 3 days preoperatively; group 3 rats were subjected to ischemia-reperfusion only; and group 4 rats were subjected to ischemia-reperfusion and received the vitamin and allopurinol combination. MAIN OUTCOME MEASURES: Activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) enzymes, the level of thiobarbituric acid-reagent substances (TBARS) and histologic grading of tissue samples. RESULTS: SOD and GSH-Px activities were decreased, but the CAT activity and TBARS level increased. Pretreatment of the rats with the allopurinol-vitamin C-vitamin E combination did not have any significant effect on the enzyme activities. However, it resulted in important reductions in the TBARS tissue levels. Histologic investigation revealed significant mucosal injury in group 3 rats compared with group 4 rats (mean [and standard deviation] for grading, 4.6 [0.5] versus 1.8 [0.4]). CONCLUSIONS: The enzymatic antioxidant defence system was significantly changed after ischemia-reperfusion and intestinal tissue was exposed to increased oxidant stress, the results of which were peroxidation of some cellular structures and increased concentrations of oxidative products. Although antioxidant treatment did not drastically affect the enzyme activities or afford complete protection of cellular structures against deformation, it apparently could eliminate oxygen radicals and prevent peroxidative reactions.
Allopurinol↗
Keratitis complicated by endophthalmitis 3 years after astigmatic keratotomy.
Endophthalmitis after keratotomy is rare and usually occurs soon after surgery. A 56-year-old woman with mild dry-eye symptoms developed keratitis complicated by endophthalmitis 3 years after astigmatic keratotomy (AK). The keratitis lasted for less than 1 day in the upper keratotomy incision. Corneal cultures yielded. Pseudomonas aeruginosa. Keratitis progressed to endophthalmitis 1 day after the detection of keratitis. The inflammation was controlled with intravitreal, subconjunctival, topical, and systemic antibiotics. This case demonstrates the potential risk of endophthalmitis developing very shortly after late keratitis of AK incisions. Vigorous early treatment and close follow-up seem justifiable in any keratitis associated with a keratotomy incision.
Anti-Bacterial Agents↗
Pars plana vitrectomy with pars plana tube implantation in eyes with intractable glaucoma.
AIMS: Intractable glaucoma is glaucoma resistant to medical therapy and conventional surgical procedures. In this study, a planned surgical technique is discussed for controlling the increased intraocular pressure in selected cases with intractable glaucoma. METHODS: Total pars plana vitrectomy with pars plana tube implantation was performed in 17 eyes of 17 cases with intractable glaucoma. Patients with neovascular glaucoma were not included in this study. The mean age of these patients (seven men, 10 women) was 44.6 (SD 22.1) years and mean follow up period was 30.3 (15.5) months (range 4-71). Drainage implants with a disc were used in 16 cases, whereas, a tube with scleral buckle (Schocket surgery) was preferred in one case. An intraocular pressure below or equal to 20 mm Hg without any adjunctive medication or with only one type of antiglaucomatous drop was considered as an adequate operative outcome. RESULTS: 16 out of 17 eyes maintained adequate pressure control. Only three out of these 16 eyes required prophylactic antiglaucomatous medications. One patient underwent reoperation for pressure control. The most severe complications observed postoperatively were intravitreal haemorrhage (one case), choroidal detachment (one case), implant failure (one case), total retinal detachment (two cases), and corneal endothelial decompensation (five cases). CONCLUSION: Pars plana placement of drainage tube following pars plana vitrectomy should be considered as an alternative method for controlling increased intraocular pressures in selected patients with intractable glaucoma.
Adolescent↗
Impaired antioxidant defense system in the kidney tissues from rabbits treated with cyclosporine. Protective effects of vitamins E and C.
Enzymatic antioxidant defense system and antioxidant defense potential (AOP) were studied in kidney tissue from rabbits treated with cyclosporine (CsA, 25 mg/kg/day), antioxidant vitamins (E, 100 mg/kg/day plus C, 200 mg/ kg/day), and CsA plus antioxidant vitamins, and in kidney tissue from control animals. Although no change was observed in superoxide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) and catalase (CAT) activities were found decreased in kidney tissue exposed to CsA for 10 days compared with control tissue. The level of thiobarbituric acid-reagent substances (TBARS) was higher and antioxidant defense potential (AOP) lower in the CsA-treated group compared with the other groups. Histopathological examination reveals important subcellular damage in the renal tissue from the animals treated with CsA. Antioxidant vitamin therapy caused full improvement in the enzyme activities, TBARS levels and AOP, but the subcellular damage was partly ameliorated in the CsA plus vitamin group. Results suggest that CsA impairs the antioxidant defense system and reduces the antioxidant defense potential in the renal tissue. Antioxidant vitamin treatment protects the tissue in part against toxic effects of the drug.
Animals↗
Antioxidant defense potential of rabbit renal tissues after ESWL: protective effects of antioxidant vitamins.
Antioxidant defense potential, malondialdehyde (MDA) levels, and relative hydroxyl radical (OH.) concentrations were measured in order to establish the effects of extracorporeal shock wave lithotripsy (ESWL) on free radical production and antioxidant defense potential of the rabbit kidney tissues. Electron microscopic examination was also performed to observe ultrastructural changes. The antioxidant defense potential of the ESWL-treated tissues was found to be reduced, and the MDA levels increased as compared with controls. Vitamin (vitamin E plus C combination) pretreatment ameliorated antioxidant defense potential in part, prevented increases in MDA levels in the ESWL-treated tissues, and increased the antioxidant defense potential in the control kidney tissues. After ESWL, a significant amount of OH. radical was measured in the affected tissue. This revealed the source of oxidant stress and peroxidation reactions in the ESWL-treated kidney tissue. Vitamin pretreatment caused significant reduction in the OH. radical concentration. In the electron microscopic investigation, some significant subcellular changes, such as endothelial injury, loss of foot processes, damage of glomerular basal membrane, etc., were observed in the ESWL-treated renal tissue slices. Vitamin pretreatment to a great extent prevented formation of these subcellular changes. Our results suggest that the antioxidant capacity of the kidney tissue was reduced after ESWL treatment and that the tissue was exposed to oxidant stress. Vitamin pretreatment exerted significant protection against the radical damage.
Animals↗
Antioxidant interferences in superoxide dismutase activity methods using superoxide radical as substrate.
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Animals↗
Antioxidant potential of cancerous human kidney tissues.
Antioxidant potentials (AOP) of cancerous and noncancerous adjacent human kidney tissues from 12 patients were measured. AOP of the cancerous tissues was found to be significantly lower than that of noncancerous ones. However, tissue malondialdehyde (MDA) levels were significantly higher in the cancerous tissues compared with noncancerous ones. In the intra-correlation analysis, carried out between AOP and MDA levels, significant correlation was found in the cancerous tissues (r = 0.9) but no correlation observed in the noncancerous ones. In the inter-correlation analysis, negative correlation was found between AOP's of cancerous and noncancerous tissues (r = -0.49) and positive correlation between MDA levels (r = 0.51). Results suggest that antioxidant potential of cancerous kidney tissues is significantly reduced compared with noncancerous ones. Therefore, they expose to high oxidant stress and free radical-induced peroxidative attacks, the results of which are cellular deformations.
Adult↗
An extruded encircling band straddling the cornea and corneal groove formation.
The authors report a rare consequence of an anteriorly migrated encircling silicone band. The extruded encircling band, which "cheesewired" forward through the superior and medical rectus insertions straddled the cornea firmly and formed a corneal groove. Corneal groove is an extremely rare complication of scleral buckling surgery.
Aged↗
Activities of the enzymes participating in purine and free-radical metabolism in cancerous human colorectal tissues.
Activities of adenosine deaminase, 5'-nucleotidase, xanthine oxidase, superoxide dismutase, glutathione peroxidase and catalase enzymes were measured in cancerous and non-cancerous adjacent colorectal tissues from 10 patients. Activities of DNA turn-over enzymes (ADA, 5'NT and XO) were found increased and those of free-radical metabolizing enzymes (SOD, GSH-Px and CAT) decreased in cancerous tissues compared with those of non-cancerous adjacent ones. Malondialdehyde (MDA) concentrations in cancerous tissues were also found higher than those of non-cancerous tissues, which indicated accelerated lipid peroxidation in the cancerous tissues. In the correlation analysis, disordered enzymatical relations were observed between the enzymes of both metabolic pathways. Results suggest that activities of purine metabolizing enzymes increase to cope with accelerated purine metabolism in cancerous tissues and, enzymatic antioxidant defense potential of cancerous tissues decreases due to carcinogenic processes in the tissues. Reduced antioxidant defense system makes the cancerous tissue more vulnerable to toxic effects of some free-radical species.
5'-Nucleotidase↗
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 stage 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.
Aged↗
Impaired antioxidant defence in guinea pig heart tissues treated with halothane.
PURPOSE: To investigate the effects of halothane and halothane plus vitamin E treatment on myocardial free radical metabolism in guinea pigs. METHODS: Four groups of seven animals were studied: control, halothane, halothane plus vitamin E and vitamin E groups. In the halothane group, halothane 1.5% in oxygen was given for 90 min over three days. In the halothane plus vitamin E group, 300 mg.kg-1.day-1 vitamin E im was started three days before the first halothane treatment and continued for three days. Following sacrifice, the hearts were assayed for superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) and malondialdehyde (MDA) level was determined. Electron spin resonance (ESR) analysis and electron microscopy (EM) were also performed. RESULTS: In the halothane group, SOD activities and MDA concentrations were increased compared with control and GSH-Px and CAT activities were decreased. In the halothane plus vitamin E group, there were no differences in enzyme activity compared with halothane alone but the MDA level was decreased. In the vitamin E group, enzyme activities were increased compared with control. Mainly the CF3CHCl radical was identified by ESR analysis in heart tissues exposed to halothane and the concentration of this radical was reduced by vitamin E. Electron microscopy showed cytoplasmic vacuolisation and dilation in sarcoplasmic reticulum in the heart tissues exposed to halothane: both were prevented by vitamin E. CONCLUSION: Although halothane causes impairment in enzymatic antioxidant defence potential, due to lowered GSH-Px and CAT activity, and accelerates peroxidative reactions in the tissues affected, no subcellular damage occurred. Vitamin E may protect tissues against free radical attack by scavenging toxic free radicals formed in heart tissue during halothane anaesthesia.
Anesthetics, Inhalation↗
Glycosaminoglycan content of Ca-oxalate stone matrix. Effect of this factor on stone fragility.
To evaluate the fragility of Ca-oxalate monohydrate stones in terms of high energy shock wave effectivity, we measured the glycosaminoglycan (GAG) content of the organic stone matrix of 35 patients who had undergone extracorporeal shock wave lithotripsy (ESWL) treatment for renal pelvic stones. The patients were classified into 3 different groups with respect to the rate of stone disintegration. While group I consisted of patients in whom only one ESWL session was needed to complete disintegration, in group II there were patients requiring 3 or more sessions for complete stone disintegration. On the other hand, patients in whom no sign of disintegration was observed despite 3 ESWL sessions constituted group III. Following this procedure, comparative evaluation of the GAG content of the stone matrix per dry stone weight in each group revealed a statistically significant difference between the first 2 and the 3rd group (p < 0.05). Our results indicated that as the GAG content of the stone matrix decreased, the efficiency of the shock waves on stone disintegration also prominently decreased, disintegration being impossible in some cases. On the other hand, the stones which were found to have higher amounts of GAGs in the organic matrix tended to be more fragile and were easily disintegrated with shock waves. In our study group the chemical composition of Ca-oxalate monohydrate stones, e.g. the matrix GAG content, seemed to be important with regard to the disintegrative effect of high energy shock waves.
Adult↗
Influence of experimental spermatic cord torsion on the contralateral testis in rats. Evaluation of tissue free oxygen radical scavenger enzyme levels.
To evaluate the degree of ischemia formation in the contralateral testicle following unilateral testicular torsion, free oxygen radical formation after detorsion or an orchiectomy procedure in terms of superoxide dismutase (SOD) and catalase activities was detected in adult male Wistar rats. Animals were divided into 4 groups and following 2 and 6 h of unilateral torsion, the orchiectomy or detorsion procedures were performed and free radical scavenger enzyme activities (SOD, catalase) were measured in the contralateral testes after 24 h, 1 week and 1 month. Evaluation of our results revealed no meaningful ischemia formation in the contralateral testes of rats undergoing 2 h of unilateral testicular torsion. However, animals undergoing 6 h of unilateral testicular torsion demonstrated a statistically significant alteration with respect to enzyme concentrations. Alterations in the contralateral testes were more prominent in animals that had undergone the detorsion procedure following 6 h of testicular torsion. Our results indicate that preservation of twisted testes through a detorsion procedure could cause further deterioration by way of reperfusion injury, indicating the importance of removal of the damaged testicle to minimize long-term histopathologic alterations in the contralateral testes.
Animals↗
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.
Animals↗
Activity of the enzymes participating in purine metabolism of cancerous and noncancerous human kidney tissues.
In this study, activity of some of the key enzymes participating in purine metabolism was measured in cancerous and noncancerous human kidney tissues from 18 patients with renal cell carcinoma. Twelve cancerous tissues were at stage T1-T2 and 6 tissues were at stage T3-T4. Adenosine deaminase (ADA) and guanase (GUA) activity was increased and xanthine oxidase (XO) activity decreased in cancerous tissues compared to noncancerous ones. No difference was, however, found between 5'-Nucleotidase (5'-NT) activity of the tissues. There were also no statistically meaningful differences between the enzyme activities of the cancerous tissues at stage T1-2 and T3-4. Results suggest that the changes observed in the activity of the enzymes participating in purine metabolism result from accelerated DNA turnover in the cancerous tissues and cells, and these changes might provide selective advantage, possibly by causing acceleration of salvage pathway activity, to the cancer cells to grow and develop more rapidly.
5'-Nucleotidase↗
Bilateral megalocornea with unilateral lens subluxation.
Megalocornea refers to an enlarged cornea that measures 13 mm or more in horizontal diameter in the absence of raised intraocular pressure. We describe a five-month-old boy with bilateral megalocornea with unilateral lens subluxation. No other ophthalmological abnormality was present. In all previously reported cases with megalocornea and ectopia lentis, the lens was cataractous and the dislocation was in the inferior and posterior direction. In contrast, our case had a clear lens which was displaced superonasally.
Cornea↗