Seyithan Taysi

Lipid peroxidation, some extracellular antioxidants, and antioxidant enzymes in serum of patients with rheumatoid arthritis

Abstract The aims of our study were to assess whether the increased oxidative stress in inflamed joints is reflected by serum lipid peroxidation and also to check alterations in the levels of extracellular antioxidants and antioxidant enzyme activities in patients with rheumatoid arthritis. Serum malondialdehyde and ceruloplasmin levels and the activity of CuZn superoxide dismutase were higher, while transferrin levels and the activities of glutathione peroxidase and catalase were lower in patients (n=37) than in healthy controls (n=30). Disease activity score correlated positively with serum malondialdehyde level and CuZn superoxide dismutase activity. Probably, superoxide radicals in serum could be dismutated to produce hydrogen peroxide by increased CuZn superoxide dismutase activity, but hydrogen peroxide could not have been detoxified due to decreased activities of serum glutathione peroxidase and catalase. Hydrogen peroxide possibly converted to hydroxyl radical by iron due to lower transferrin level might have led to increased serum lipid peroxidation in patients with rheumatoid arthritis.

Melatonin reduces lipid peroxidation and nitric oxide during irradiation-induced oxidative injury in the rat liver.

Abstract:  Radiation therapy is a popular and useful tool in the treatment of cancer. Melatonin participates in the regulation of a number of important physiological and pathological processes. Melatonin, a powerful endogenous antioxidant, plays a role in the reduction of oxidative damage. Thirty adult rats were divided into five equal groups. On the day of the experiment, groups I and II were injected with 5 or 10 mg/kg melatonin, respectively, while group III received isotonic NaCl solution. Thirty minutes later, groups I, II and III were exposed to 6.0 Gy whole body ionizing radiation in a single fraction. Group IV was injected with 5 mg/kg melatonin but was not irradiated. The final group was reserved as sham treated. Liver malondialdehyde (MDA) and nitric oxide (NOċ) levels were measured in all groups. Whole body irradiation caused a significant increase in liver MDA and NOċ levels. Hepatic MDA and NOċ levels in irradiated rats that were pretreated with melatonin (5 or 10 mg/kg) were significantly decreased. Malondialdehyde and NOċ levels were reduced in a dose‐related manner by melatonin. The data show that melatonin reduces liver damage inflicted by irradiation when given prior to the exposure to ionizing radiation. The radioprotective effect of melatonin is likely achieved by its ability to function as a scavenger for free radicals generated by ionizing radiation.

Serum Oxidant/Antioxidant Status of Patients with Systemic Lupus Erythematosus

Abstract The levels of malondialdehyde and ceruloplasmin, and superoxide dismutase activity were higher, while transferrin concentration and the activities of glutathione peroxidase and catalase were lower in serum of patients with systemic lupus erythematosus (n=24) compared with healthy controls (n=20). Disease activity index correlated positively with serum malondialdehyde level (r=0.47, p<0.05), erythrocyte sedimentation rate (r=0.41, p<0.05) and C-reactive protein concentration (r=0.41, p<0.05), while it correlated negatively with serum superoxide dismutase (r=0.42, p<0.05) and glutathione peroxidase (r= −0.44, p<0.05) activities in patients. No such correlations were found in healthy control subjects. It remains to be seen whether correlations found between disease activity score and serum malondialdehyde level, and also activities of serum superoxide dismutase and glutathione peroxidase enzymes observed in the present study may be used to predict prognosis in patients with systemic lupus erythematosus.

Malondialdehyde and Nitric Oxide Levels in the Plasma of Patients with Advanced Laryngeal Cancer

AbstractPurpose. We investigated alterations in plasma nitrite, nitrate, total nitric oxide (NO•), and malondialdehyde (MDA) levels in patients with advanced stage laryngeal cancer. Methods. We measured the levels of MDA and total NO−2, as well as the NO−3 marker for NO• generation, in 25 patients with advanced laryngeal cancer and 15 healthy control subjects. Results. The levels of plasma MDA, NO•, and NO−3 were significantly higher in the patients with laryngeal cancer than in the healthy controls (P ≪ 0.001 for all). On the other hand, although plasma NO−2 was increased in the patient group, the statistical difference was not significant (P ≫ 0.05). Moreover, the MDA and NO• levels did not differ significantly between patients with stage III and stage IV laryngeal cancer. Conclusion. These findings demonstrate that oxidative stress is increased in patients with advanced laryngeal cancer.

Protective role of intramuscularly administered vitamin E on the levels of lipid peroxidation and the activities of antioxidant enzymes in the lens of rats made cataractous with gamma-irradiation.

Purpose To determine the antioxidant role of vitamin E (VE) (10 mg/kg/day) against radiation-induced cataract in lens after total-cranium irradiation of rats with a single dose of 5 Gy. Methods Sprague-Dawley rats were divided into three groups. Group 1 did not receive VE or irradiation but received both 0.1 ml physiologic saline intraperitoneally and sham irradiation (control group). Group 2 received to total cranium 5 Gy of gamma irradiation as a single dose (RT group) plus 0.1 ml physiologic saline intraperitoneally. Group 3 received irradiation to total cranium plus 10 mg/kg/day VE (RT+VE group). The rats were irradiated using a cobalt-60 teletherapy unit. Chylacks cataract classification (1) was used in this study. At the end of 10 days, the rats were killed and their eyes were enucleated to measure the antioxidant enzymes (the activity of superoxide dismutase [SOD], glutathione peroxidase [GSH-Px]) and lipid peroxidation level (malondialdehyde [MDA]). Results While grade 1 cataract development was detectable in seven rats in the RT group, it was detectable only in two rats in the RT+VE group, whereas none of the rats in the control group exhibited any biomicroscopic change in their lenses. MDA level and GSH-Px activity in the rat lens in the RT group was significantly higher than in the control group. SOD activity in the RT group was lower than in the control group. The activity of SOD and GSH-Px enzymes was higher in the RT+VE group, but MDA level was lower in the RT+VE group when compared with the RT group. Conclusions Vitamin E has a protective effect on radiation-induced cataract by decreasing oxidative stress.

Elevated serum arginase activity levels in patients with breast cancer.

AbstractPurpose. Recently, the high activity of arginase enzyme has been observed in the sera of malignant neoplasms. In this pathogenic condition, it is said that arginase strongly inhibits lymphocyte proliferation and plays a role in providing ornithine as a substrate for biosynthesis of polyamines, which have been found in various types of cancer. The aim of this study was to examine the arginase activity levels in breast cancer as a marker. Methods. We evaluated the serum arginase activity levels in 48 females with breast cancer, in 30 females with benign disease, and in 50 healthy control subjects. The serum arginase activities were determined according to the slightly modified method of Chinard. Results. The mean activity of arginase was found to be high in the early stages (n = 27, stage I + II, P ≪ 0.01), and higher in the advanced states (n = 21, stage III + IV, P ≪ 0.001) of the malignant group in comparison with those of the normal subjects. Conclusion. A high arginase level in breast cancer was observed to possibly be released into the serum: namely, the more advanced the breast cancer, the higher the serum level of arginase enzyme activity. Therefore, this enzyme might serve as a useful biological marker in breast cancer while also being an indicator of breast cancer progression.

The Effect of Melatonin against Oxidative Damage during Total-Body Irradiation in Rats

Abstract Koc, M., Taysi, S., Buyukokuroglu, M. E. and Bakan, N. The Effect of Melatonin against Oxidative Damage during Total-Body Irradiation in Rats. Radiat. Res. 160, 251–255 (2003). Melatonin has been reported to participate in the regulation of a number of important physiological and pathological processes. Melatonin, which is a powerful endogenous antioxidant, may play a role in the prevention of oxidative damage. The aim of this study was to investigate the effect of pretreatment with melatonin (5 mg kg–1 and 10 mg kg–1) on γ-radiation-induced oxidative damage in plasma and erythrocytes after total-body irradiation with a single dose of 5 Gy. Total-body irradiation resulted in a significant increase in plasma and erythrocyte MDA levels. Melatonin alone increased the levels of SOD and GSH-Px. Erythrocyte and plasma MDA levels in irradiated rats that were pretreated with melatonin (5 or 10 mg kg–1) were significantly lower than those in rats that were not pretreated. There was no significant difference between the effects of 5 and 10 mg kg–1 on plasma MDA activities and CAT activities. However, erythrocyte MDA levels showed a dose-dependent decrease, while GSH-Px activities increased with dose. Our study suggests that melatonin administered prior to irradiation may protect against the damage produced by radiation by the up-regulation of antioxidant enzymes and by scavenging free radicals generated by ionizing radiation.

Effects of aqueous extracts of Satureja hortensis L. on rhinosinusitis treatment in rabbit.

Satureja hortensis L. (Lamiaceae) is an annual herb that used as traditional folk medicine in Eastern Anatolia region of Turkey for treatment of different infectious diseases and disorders. This study was designated to investigate anti-inflammatory effect of aqueous extract (250 mg/kg) of Satureja hortensis. Therapeutic potential of Satureja hortensis as an anti-inflammatory agent was examined by measurement of NO* metabolites and histological changes in a rabbit model of rhinosinusitis. The results showed that both activity of NOS enzyme and concentration of NO* metabolites were significantly reduced by topical administration of Satureja hortensis extract. Histological examination demonstrated no edema and/or reduced inflammation in therapy group as compared to the control. Thus, the data suggest Satureja hortensis extract may have the potential to be used as anti-inflammation agent, and can be used in the treatment of rhinosinusitis diseases.

Effects of Oral Ginkgo biloba Supplementation on Cataract Formation and Oxidative Stress Occurring in Lenses of Rats Exposed to Total Cranium Radiotherapy

PurposeTo determine the antioxidant role of Ginkgo biloba (GB) in preventing radiation-induced cataracts in the lens after total-cranium irradiation of rats with a single radiation dose of 5 Gy.MethodsSprague-Dawley rats were randomly divided into three groups. Group 1 received neither GB nor irradiation (control group). Group 2 was exposed to total-cranium irradiation of 5 Gy in a single dose [radiation therapy (RT) Group], and group 3 received total cranium irradiation from a cobalt-60 teletherapy unit, plus 40 mg/kg per day GB (RT+GB group). At the end of the tenth day, the rats were killed and their eyes were enucleated to measure the antioxidant enzymes, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the lipid peroxidation level [malondialdehyde (MDA)].ResultsIrradiation significantly increased both the MDA level and the activity of GSH-Px, and significantly decreased the activity of SOD in the rat lenses. GB supplementation significantly increased the activities of SOD and GSH-Px enzymes and significantly decreased the MDA level. Total cranium irradiation of 5 Gy in a single dose promoted cataract formation, and GB supplementation protected the lenses from radiation-induced cataracts.ConclusionsWe suggest that Ginkgo biloba is an antioxidant that protects the rat lens from radiation-induced cataracts.

Oxidant/antioxidant status in men with Behçet’s disease

Behçet’s disease (BD) is a chronic, progressive disorder that affects many systems of the body including the eye. The aim of this study was to assess whether the increase in oxidative stress in the affected tissues is reflected by lipid peroxidation and to check for alterations in antioxidants and antioxidant enzyme activities in patients with BD. Erythrocyte antioxidant potential (AOP), glutathione (GSH) and GSH-dependent enzymes (glutathione peroxidase (GSH-Px), glutathione reductase (GRD) and glutathione-S-transferase (GST), catalase (CAT), Cu–Zn superoxide dismutase (Cu–Zn SOD) activities, malondialdehyde (MDA) and some trace elements (zinc, Zn; copper, Cu; manganese, Mn) levels in men with BD. Erythrocyte CAT, GSH-Px activities, MDA, GSH, AOP and serum Zn values were significantly lower in patients with BD than in the control group. However, erythrocyte Cu–Zn SOD, GRD activities, erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP) and Cu values were significantly higher in patients with BD than in the control group, but GST activity and serum Mn values were unchanged. In conclusion, our results confirm the presence of oxidative stress in patients with BD and suggest that the severity of BD may arise from impaired antioxidant mechanisms. Therapy with antioxidants may lead to the increase in the antioxidant defense system and thus improvement in clinical symptoms.