Şule Coşkun

Effects of Continuous and Intermittent Magnetic Fields on Oxidative Parameters In vivo

Continuous and intermittent 50 Hz, 1.5 mT magnetic field with the exposure period of 4 h/day for 4 days was used to investigate its possible effect on adult guinea pigs. Tissues and plasma specimens were assessed by biochemical parameters. Malondialdehyde (MDA), glutathione (GSH), nitric oxide (NO) levels and myeloperoxidase activity (MPO) were examined in plasma, liver and brain tissues. All parameters were determined by spectrophotometer. While intermittent magnetic field was effective on plasma lipid peroxidation, continuous magnetic field was found to be effective on plasma MPO activity and NO levels. Augmentation of lipid peroxidation was also observed in liver tissue both intermittent and continuous magnetic field exposures. These results indicate that both the intermittent and continuous magnetic field exposures affect various tissues in a distinct manner because of having different tissue antioxidant status and responses.

The effects of dexfenfluramine administration on brain serotonin immunoreactivity and lipid peroxidation in mice

Obesity continues to be an increasing health problem in worldwide and antiobesity drugs have commonly been used by obese patients. During the use of anorectic drugs, the antioxidant defense may be affected, especially by reactive oxygen species. It was decided to investigate the effects of dexfenfluramine on body weight, daily food intake, brain thiobarbituric acid-reactive substances (TBARS), glutathione (GSH) and nitric oxide (NO) levels, and 5-HT immunoreactivity. Mice were divided into two groups each containing 8 Swiss Albino adult (6 months) mice. Group 1, untreated, was used as a control; group 2 was treated with dexfenfluramine 0.4 mg/kg per day intraperitoneally for 7 days. Brain TBARS and GSH levels were assayed spectrophotometrically. The stable end-products of NO, nitrite and nitrate, were analyzed spectrophotometrically. Brain tissue 5-HT immunoreactivity was observed using an immunohistochemical method. There were significant decreases in body weight in the dexfenfluramine group (p < 0.05). Although brain GSH and NOx levels decreased significantly, brain TBARS levels increased in the dexfenfluramine group (p < 0.05). Brain 5-HT immunoreactivity also increased in the dexfenfluramine-treated group compared to control. In conclusion, our findings show that dexfenfluramine is effective in achieving weight loss and also increases lipid peroxidation in mouse brain.

Effects of Epidermal Growth Factor on Lipid Peroxidation and Nitric Oxide Levels in Oral Mucosal Ulcer Healing: A Time-Course Study

PurposeEpidermal growth factor (EGF) has been used as a vulnerary agent. Epidermal growth factor accelerates wound healing. Nitric oxide (NO) is considered to be an important factor which is involved in wound healing. The objective of this study was to examine the effects of interactions between exogenous EGF and NOx which may have either similar or quite opposed properties in the process of oral wound repair on different days. In addition, lipid peroxidation was found to be an indicator of free radical damage.MethodsFive-month-old New Zealand albino male rabbits were used for this study. A surgical incision was made in the right mandibula diestema region of the rabbits, which were then divided into controls and EGF implanted groups. All parameters were analyzed by spectrophotometry.ResultsIn the EGF-implanted groups, both the NOx and lipid peroxidation indicator levels significantly decreased in comparison to those of the control groups on the first day after wounding. However, on the 3rd and 5th days after wounding, the NOx levels of the tissue strips also decreased in both modalities, but there was no significant alteration between the 3rd and 5th day after wounding.ConclusionIt was concluded that EGF affects oral wound healing by downregulating both the lipid peroxidation and NOx levels, and it may thus be considered to be an oxygen radical scavenger.

The effect of repeated tryptophan administration on body weight, food intake, brain lipid peroxidation and serotonin immunoreactivity in mice

Tryptophan as a circulating precursor of serotonin (5-HT) may suppress food intake and body weight. Tryptophan administration can enhance the generation of reactive oxygen species (ROS) by inducing oxidative pathway in vivo and in vitro. We have examined the effect of repeated tryptophan administration on food consumption, body weight, brain lipid peroxidation and 5-HT immunoreactivity. Tryptophan was given at the dose of 100 mg/kg/24 hr in 0.2 ml saline solution i.p. for 7 days to mice. Control mice received 0.9% NaCL solution at the same manner and volume. Body weights were recorded at the beginning and end of the experiments. Thiobarbituric acid reactive substance (TBARS), the last product of lipid peroxidation, was measured spectrophotometrically. Brain 5-HT levels were determined by the immunohistochemical method. Our findings indicate that the tryptophan suppresses food intake significantly in mice. Body weight decreased and brain TBARS levels increased significantly by repeated tryptophan treatment. Immunohistochemical detection showed that 5-HT levels increased by tryptophan administration. There is a link between increased 5-HT level and oxidative stress by tryptophan administration on brain tissue. Tryptophan at repeated doses should be exercised carefully in clinical practice.

Relations between Concentrations of Asymmetric Dimethylarginine and Neopterin as Potential Risk Factors for Cardiovascular Diseases in Haemodialysis-Treated Patients

Objectives. To investigate the correlation between concentrations of asymmetric dimethylarginine (ADMA) and neopterin (NP) as potential risk factors for cardiovascular diseases in chronic renal failure patients. Method. In this study, 33 patients with renal failure before and after haemodialysis were compared with healthy control subjects. Serum ADMA and NP levels were measured using high performance liquid chromatography (HPLC). Results. When ADMA and NP concentrations in renal failure patients were compared before and after dialysis, before dialysis ADMA and NP concentrations were higher than those in the control group. However, ADMA and NP levels showed a falling mean and clear after dialysis. While there is no correlation between ADMA and NP levels before dialysis, there is a mean and positive correlation between ADMA and NP levels after dialysis. Conclusion. Potential risk factors for cardiovascular diseases include high concentrations of both ADMA and NP levels in chronic renal failure patients. A correlation mean between ADMA and NP levels after dialysis was found, but no correlation between ADMA and NP levels before haemodialysis was discovered. These can be evaluated as two different risk factors independent from each other.

Effect of transforming growth factor beta 1 (TGF-beta 1) on nitric oxide production and lipid peroxidation in oral mucosal wound healing

Wound healing is a highly orchestrated process including complex and coordinated interactions involving peptide growth factors of which transforming growth factor-beta (TGF-beta) is one of the most important modulators. Exogenous TGF-beta treatment has been shown to accelerate wound healing in normal and impaired animal models. Nitric oxide (NO) also plays a key role in wound healing. The objective of this study is to examine the effects of exogenous TGF-beta 1 treatment on NO and lipid peroxidation levels in the process of oral wound healing on different days. In this study, we used 5-month-old New Zealand albino male rabbits. After a standard surgical incision in the diestema region, the rabbits were divided into controls and TGF-beta 1 implanted groups. NO levels and malondialdeyhde (MDA) levels which are indicators of lipid peroxidation were determined by spectrophotometry. In the TGF-beta 1 implanted groups, both NO and MDA levels significantly increased only on the third day after wounding when compared to control groups. We found decreased MDA levels parallel to NO levels on the fifth day after wounding. These findings suggest that TGF-beta 1 affects mucosal wound healing by altering NO production on different days of wounding. TGF-beta 1 may regulate NO production by its dual effect in as both an activator and inhibitor an in oral mucosal healing.

Effect of two strains of Lactobacillus delbruckii subsp. bulgaricus on nitric oxide generation and antioxidant status of rat small intestine

In this article we study the effect of diets supplemented with two strains of Lactobacillus delbruckii subsp. bulgaricus (B3 and A13, which produced the highest and lowest amount of exopolysaccharide, respectively) on generation of intestinal nitric oxide (NO) and antioxidant status. The oxidative status in terms of thiobarbituric acid-reactive substances (TBARS) and NO levels in small intestinal tissues were measured. We also determined intestinal nonenzymatic antioxidant levels after supplementation with two strains of L. delbruckii subsp. bulgaricus. In rats, dietary supplementation with both lactobacilli strains resulted in a nearly 1.5-fold increase in NO level in the small intestine. Increases in NO production may contribute to lipid peroxidation in the small intestine. However, at the same time, diets supplemented with both strains of L. delbruckii subsp. bulgaricus enhance the antioxidant capacity of the gastrointestinal system in rats. These probiotics could be used as important adjuvants to maintain balance in the gut, although more studies are required to demonstrate their efficacy in humans.

Effect of exogenous epidermal growth factor (EGF) on nonenzymatic antioxidant capacities and MPO activity of wound tissue

Growth factors and cytokines are key regulators of the wound-healing process. Epidermal growth factor (EGF) plays a vital role during the process of wound healing. There are limited numbers of studies related to EGF implantation effects on oxidative stress in oral wound healing. The objective of this study was to investigate the effect of EGF on myeloperoxidase (MPO) activity and nonenzymatic antioxidant levels of oral wound tissue on different days. In this study, New Zealand male albino rabbits were used. After submucosal incisions, the rabbits were divided into two equal groups: untreated wounds, and EGF-implanted wounds. The levels of glutathione (GSH), ascorbic acid (AA), and MPO activity were measured spectrophotometrically. As a result, MPO activity of oral wound tissue strips was increased by exogenous EGF treatment compared with controls. In addition, GSH and AA levels of oral wound tissue strips were not changed during oral wound-healing phases for both controls and experimental groups.