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Namik Delibas

Publications and source records attributed to Namik Delibas.

At least 19 recordsLinked to original sources
PubMed2006

Melatonin increases NMDA receptor subunits 2A and 2B concentrations in rat hippocampus.

We investigated that the effects of melatonin on N-methyl-D: -aspartat receptor (NMDAR) subunits 2A and 2B concentrations and on markers of oxidative stress in hippocampus of rats treated with melatonin for 4 weeks. Animals were divided into four groups according to their melatonin doses (control group (C), n = 7; 5 mg/kg group (M5), n = 7; 10 mg/kg group (M10), n = 8; 20 mg/kg group (M20), n = 8) and received the melatonin as intraperitoneal injection. After 4 weeks of treatment, electrophoretic examination was done using sodium dodecyl sulfate/polyacrilamide gel electrophoresis (SDS-PAGE) and Western blotting in hippocampal homogenates of different groups. Malondialdehyde (MDA), an end product of lipid peroxidation, was assayed in all groups. There were significant increases in both NMDAR 2A; 5 mg/kg group (n = 3, p < 0.05), 10 mg/kg group (n = 3, p < 0.05), 20 mg/kg group (n = 3, p < 0.05) and NMDAR 2B expressions; 5 mg group (n = 3, p < 0.05), 10 mg group (n = 3, p < 0.05), 20 mg group (n = 3, p < 0.05), compared to the control group. No significant difference in MDA concentrations was found between groups. The present study clearly demonstrates that melatonin alters hippocampal NMDAR subunit concentrations in a dose-dependent manner without causing lipid peroxidation.

Animals↗
PubMed2006

Melatonin modulates 900 Mhz microwave-induced lipid peroxidation changes in rat brain.

Microwaves (MW) from cellular phones may affect biological systems by increasing free radicals, which may enhance lipid peroxidation levels of the brain, thus leading to oxidative damage. Melatonin is synthesized in and secreted by the pineal gland at night and exhibits anti-oxidant properties. Several studies suggest that supplementation with anti-oxidant can influence MW-induced brain damage. The present study was designed to determine the effects of MW on the brain lipid peroxidation system, and the possible protective effects of melatonin on brain degeneration induced by MW. Twenty-eight Sprague-Dawley male rats were randomly divided into three groups as follows: (1) sham-operated control group (N = 8); (2) study 900-MHz MW-exposed group (N = 8); and (3) 900-MHz MW-exposed+melatonin (100 microg/kg sc before daily MW exposure treated group) (N = 10). Cortex brain and hippocampus tissues were removed to study the levels of lipid peroxidation as malonyl dialdehyde. The levels of lipid peroxidation in the brain cortex and hippocampus increased in the MW group compared with the control group, although the levels in the hippocampus were decreased by MW+melatonin administration. The brain cortex lipid peroxidation levels were unaffected by melatonin treatment. We conclude that melatonin may prevent MW-induced oxidative changes in the hippocampus by strengthening the anti-oxidant defense system, by reducing oxidative stress products.

Animals↗
PubMed2005

The effect of long-term low-dose lead exposure on thyroid function in adolescents.

This study investigated blood lead (Pb-B) levels and Pb-B effects on thyroid functions in long-term low-level-lead-exposed male adolescents who work as auto repairers. Pb-B and ALAD index (logarithm of activated delta-aminolaevulinic acid dehydratase/nonactivated delta-aminolaevulinic acid dehydratase) were measured as indicators of exposure to lead. Thyroid function tests including free thyroxine (FT4), free triiodothyronine (FT3), and thyrotrophin (TSH) were conducted and thyroid ultrasounds were performed in 42 lead-exposed adolescents and 55 healthy control subjects. Mean Pb-B levels and ALAD index were found significantly higher in the study group than in the normal control group (7.3+/-2.92 microg/dl vs. 2.08+/-1.24 microg/dl, P < 0.001 and 0.44+/-0.26 vs. 0.29+/-0.23, P < 0.05, respectively). FT4 levels were found significantly lower in the study group (1.02+/-0.18 mI/mL and 1.12+/-0.14 mIU/mL, P < 0.05). No subject in the control group had an abnormal FT4 level, but FT4 levels were found under normal limits in 11 subjects (26%) in the study group. FT3 and TSH levels in the study and control groups did not differ (P > 0.05). Thyroid volumes in the study and control groups did not exhibit any significant differences (P > 0.05). Pb-B was found to be negatively correlated to FT4 levels (r = -0.20, P = 0.044). This study revealed that long-term low-level lead exposure may lead to reduced FT4 level without significant changes in TSH and T3 levels in adolescents even at low Pb-B levels.

Adolescent↗
PubMed2005

Does melatonin protect or treat brain damage from traumatic oxidative stress?

A variety of experimental studies have demonstrated the neuroprotective effects of melatonin, based on its antioxidant activity. In a prospective randomized study, the effects of melatonin were investigated in experimental head trauma-induced oxidative stress in rabbits. The experimental study was performed on 30 rabbits. The animals were divided into three groups. Group I (sham procedure): a right parietal craniotomy was performed on each animal, and the dura mater was left intact. Group II: experimental brain trauma (EBT) was performed on each animal using a 1 cm inner diameter x 10 cm long glass tube, through which a 20 g weight (0.5 cm diameter) was dropped onto the brain at the craniotomy site, causing a contusional head trauma. Group III: the same EBT model was performed, but 2.5 mg/kg melatonin was injected intraperitoneally four times (total dose 10 mg/kg); these injections were performed 20 min before the operation, during the trauma, 1 h later and 2 h later. The rabbits were sacrificed after the EBT at 24 h after the brain trauma. The activities of the three principal antioxidant enzymes-catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px)-were determined, and the levels of malondialdehyde (MDA), a product of lipid peroxidation, and glutathione (GSH) were measured in brain homogenates. MDA levels were found to be higher in the EBT group than in the EBT+melatonin group or the sham procedure group. The SOD activity was found to be higher in the EBT group than in the sham procedure group. Enzymatic parameters (except for SOD) were significantly higher in melatonin-treated animals than in EBT animals. GSH levels in melatonin-treated animals were decreased compared with EBT animals. In conclusion, the data indicate that melatonin protects against free radical-mediated oxidative changes in brain tissue by boosting antioxidant enzymes, and in particular lowering lipid peroxidation in rabbits with EBT.

Animals↗
PubMed2005

Vascular wall damage in rats induced by organophosphorus insecticide methidathion.

We have examined the effect of subchronic methidathion (MD) administration on vascular wall damage. The experimental groups were: control group and rats treated with 5 mg/kg MD. The MD group was given MD by gavage for 5 days a week for 4 weeks at a dose level of 5 mg/kg per day by using corn oil as the vehicle. The levels of malondialdehyde (MDA) were determined in the vascular tissue. Histopathological examination was examined in the thoracic aortic tissue. The levels of MDA were increased in the MD group compared with the control group (P < 0.01). In the MD group, subchronic MD administration led to the irregulation, prominent breaks and fragmentation of the elastic fibers were located in the media of aortic wall. In conclusion, it is likely that subchronic MD administration caused vascular wall damage and, in addition, lipid peroxidation may be one of the molecular mechanisms involved in MD-induced vascular toxicity.

Animals↗
PubMed2005

The effects of isoniazid on hippocampal NMDA receptors: protective role of erdosteine.

Isoniazid (INH) has neurotoxic effects such as seizure, poor concentration, subtle reduction in memory, anxiety, depression and psychosis. INH-induced toxic effects are thought to be through increased oxidative stress, and these effects have been shown to be prevented by antioxidant therapies in various organs. Increased oxidative stress may be playing a role in these neurotoxic effects. N-methyl D-aspartat receptors (NMDA) are a member of the ionotropic group of glutamate receptors. These receptors are involved in a wide variety of processes in the central nervous system including synaptogenesis, synaptic plasticity, memory and learning. Erdosteine is a potent antioxidant and mucolytic agent. We aimed to investigate adverse effects of INH on rat hippocampal NMDAR receptors, and to elucidate whether erdosteine prevents possible adverse effects of INH. In the present study, compared to control group, NMDAR2A (NR2A) receptors were significantly decreased and malondialdehyde (MDA), end product of lipid peroxidation, production was significantly increased in INH-treated group. On the other hand, administration of erdosteine to INH-treated group significantly increased NR2A receptors and decreased MDA production. In conclusion, decreasing NR2A receptors in hippocampus and increasing lipid peroxidation correlates with the degree of oxidative effects of INH and erdosteine protects above effect of INH on NR2A receptors and membrane damage due to lipid peroxidation by its antioxidant properties.

Animals↗
PubMed2005

Nitric oxide level in the nasal and sinus mucosa after exposure to electromagnetic field.

OBJECTIVE: The purpose of this study was to examine the changes in nitric oxide (NO) level in the nasal and paranasal sinus mucosa after exposure radiofrequency electromagnetic fields (EMF). STUDY DESIGN AND SETTING: Thirty male Sprague-Dawley rats were randomly grouped as follows: EMF group (group I; n, 10), EMF group in which melatonin received (group II; n, 10) and the control (sham operated) group (group III; n, 10). Groups I and II were exposed to a 900 MHz. Oral melatonin was given in group II. Control rats (group III) were also placed in the tube as the exposure groups, but without exposure to EMF. At the end of 2 weeks, the rats were sacrificed, and the nasal and paranasal sinus mucosa dissected. NO was measured in nasal and paranasal mucosa. RESULTS: The nasal and paranasal sinus mucosa NO levels of group I were significantly higher than those of the control group (group III) ( P < 0.05). However, there was no statistically significant difference between group II and the control group (group III) regarding NO output ( P > 0.05). CONCLUSION: Exposure to EMF released by mobile phones (900 MHz) increase NO levels in the sinus and nasal mucosa. SIGNIFICANCE: Increased NO levels may act as a defense mechanism and presumably related to tissue damage. In addition, melatonin may have beneficial effect to prevent these changes in the mucosa.

Animals↗
PubMed2005

Effects of ischemia-reperfusion on NMDA receptor subunits 2a and 2b level in rat hippocampus.

The authors investigated the effects of ischemia and reperfusion on the N-methyl-D-aspartate receptor (NMDAR) subunits 2A and 2B concentration in rat hippocampus. At the protein level, significant increase in the amounts of NMDAR 2A and NMIDAR 2B in the rat hippocampus was observed at 1 h after reperfusion compared with control group. These results suggested that the alteration in hippocampal NMDAR2 subunit concentrations after ischemia-reperfusion might be invovlved in cognitive dysfunction and excitotoxicity.

Animals↗
PubMed2005

EFFECT of nicotine on hippocampal nicotinic acetylcholine alpha7 receptor and NMDA receptor subunits 2A and 2B expression in young and old rats.

Nicotinic acetylcholine (nAChR) and N-methyl-D-aspartate receptors (NMDARs) play critical roles in memory function. This study administered chronic nicotine to determine the alterations of N-methyl-D-aspartate receptor subunit 2A and 2B (NR2A, NR2B) and the alterations of alpha7nAChR receptor. It was determined that the effectivity of nicotine and the data support that nicotine increases hippocampal NR2A and B expression. Additionally, the role of nicotine in the cognitive improvement was not supported by the antioxidative mechanisms or the authors observed no effect of nicotine on lipid peroxidation at the hippocampus.

Age Factors↗
PubMed2005

No effects of 900 MHz and 1800 MHz electromagnetic field emitted from cellular phone on nocturnal serum melatonin levels in rats.

In this study, the effects of exposure to a 900 MHz and 1800 MHz electromagnetic field (EMF) on serum nocturnal melatonin levels of adult male Sprague-Dawley rats were studied. Thirty rats were used in three independent groups, 10 of which were exposed to 900 MHz, 10 of which were exposed to 1800 MHz and 10 of which were sham-exposed (control). The exposures were performed 30 min/day, for five days/week for four weeks to 900 MHz or 1800 MHz EMF Control animals were kept under the same environmental conditions as the study groups except with no EMF exposure. The concentration of nocturnal melatonin in the rat serum was measured by using a radioimmunoassay method. There were no statistically significant differences in serum melatonin concentrations between the 900 MHz EMF group and the sham-exposed group (P > 0.05). The values at 12:00 pm were 39.11 +/- 6.5 pg/mL in the sham-exposed group and 34.97 +/- 5.1 pg/mL in the 900 MHz EMF-exposed group. Also, there were no statistically significant differences in serum melatonin concentrations between the sham-exposed group and the 1800 MHz EMF-exposed group (P > 0.05). The values at 12:00 pm were 39.11 +/- 6.5 pg/mL in the sham-exposed group and 37.96 +/- 7.4 pg/mL in the exposed group. These results indicate that mobile phones, emitting 900 and 1800 MHz EMF, have no effect on nocturnal serum melatonin levels in rats.

Animals↗
PubMed2005

Beneficial effect of the addition of nitroglycerin to the cardioplegic solution on lipid peroxidation during coronary artery bypass surgery.

The effects of the addition of a nitric oxide (NO) donor to the cardioplegic solution on reperfusion injury and lipid peroxidation (LPO) in coronary artery bypass grafting (CABG) are not known. Therefore, this work was conducted to determine the possible effects of nitroglycerin on LPO and reperfusion injury as a result of CABG. A prospective double-blind, placebo-controlled study was conducted in 30 consecutive patients with coronary artery disease who underwent CABG with cardiopulmonary bypass. The patients were randomly assigned to receive 3 microg/kg of nitroglycerin added to the cardioplegic solution (NTG group) or 3 microg/kg of placebo added to the cardioplegic solution (placebo group). MDA increased significantly in the placebo group compared to the NTG group during the ischemic (P < 0.01) and reperfusion periods (P < 0.01). The level of troponin I decreased significantly in the NTG group compared to the placebo group during the ischemic and reperfusion periods (P < 0.001). The level of NO increased significantly in the NTG group compared to the placebo group during the ischemic and reperfusion periods (P < 0.01). LPO was increased in response to CPB during CABG, together with simultaneous decreases in serum nitric oxide levels, whereas LPO was significantly decreased in response to CPB with nitroglycerin, together with simultaneous increases in the levels of serum nitric oxide.

Cardioplegic Solutions↗
PubMed2005

Biological and morphological effects on the reproductive organ of rats after exposure to electromagnetic field.

OBJECTIVE: The biological effect of electromagnetic field (EMF) emitted from mobile phones is a current debate and still a controversial issue. Therefore, little is known on the possible adverse effects on reproduction as mobile phone bio-effects are only a very recent concern. The aim of this experimental study was to determine the biological and morphological effects of 900 MHz radiofrequency (RF) EMF on rat testes. METHODS: The study was performed in the Physiology and Histology Research Laboratories of Süleyman Demirel University, Faculty of Medicine, Isparta, Turkey in May 2004. Twenty adult male Sprague-Dawley rats weighing 270-320 gm were randomized into 2 groups of 10 animals: Group I (control group) was not exposed to EMF and Group II (EMF group) was exposed to 30 minutes per day, 5 days a week for 4 weeks to 900 MHz EMF. Testes tissues were submitted for histologic and morphologic examination. Testicular biopsy score count and the percentage of interstitial tissue to the entire testicular tissue were registered. Serum testosterone, plasma luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels were assayed biochemically. RESULTS: The weight of testes, testicular biopsy score count and the percentage of interstitial tissue to the entire testicular tissue were not significantly different in EMF group compared to the control group. However, the diameter of the seminiferous tubules and the mean height of the germinal epithelium were significantly decreased in EMF group (p<0.05). There was a significant decrease in serum total testosterone level in EMF group (p<0.05). Therefore, there was an insignificant decrease in plasma LH and FSH levels in EMF group compared to the control group (p>0.05). CONCLUSION: The biological and morphological effects resulting from 900 MHz RF EMF exposure lends no support to suggestions of adverse effect on spermatogenesis, and on germinal epithelium. Therefore, testicular morphologic alterations may possibly be due to hormonal changes.

Animals↗
PubMed2004

Renal effects and erythrocyte oxidative stress in long-term low-level lead-exposed adolescent workers in auto repair workshops.

Lead poisoning is an old but persistent public health problem in developing countries. The present study investigated blood lead levels and its effects on markers of renal function and parameters of erythrocyte oxidative stress in adolescent male auto repair workers in Turkey. Blood Pb level and the ALAD index (logarithm of activated delta-aminolaevulinic acid dehydratase/nonactivated delta-aminolaevulinic acid dehydratase) were measured as indicators of exposure to Pb. Markers of tubular damage urine N-acetyl-beta-D-glucosaminidase (NAG), beta2-microglobulin (beta-2 MG), creatinine (Cr), uric acid (UA), and calcium, markers of glomerular filtration blood urea nitrogen (BUN), serum Cr, UA, and parameters of oxidative damage in erythrocyte were studied in 79 Pb-exposed adolescent and 71 healthy control subjects. Blood lead levels and ALAD index were found significantly higher in the study group than that of normal control group. BUN, UA level, and glomerular filtration rates were detected in normal range in the lead-exposed group. Urinary NAG excretion and calciuria were higher in the study group than in controls. Urinary excretion of NAG was positively correlated with the blood lead levels (r=0.427). There was no relationship between blood lead levels and UA or beta-2 MG in urine. Malondialdehyde and glutathione peroxidase levels were significantly elevated in lead-exposed adolescents than controls, but changes in the catalase and superoxide dismutase activities in lead-exposed adolescents did not reach statistical significance. In conclusion, chronic low-dose lead exposure seems as a cause of subtle renal impacts in adolescent workers of auto repair workshops. Lead-induced oxidative stress in erythrocytes probably contributes to these subclinical renal effects.

Adolescent↗
PubMed2004

Vascular wall damage in rats induced by methidathion and ameliorating effect of vitamins E and C.

We examined the effect of subacute methidathion (MD) administration on vascular wall damage and evaluated the ameliorating effects of combination of vitamins E and C against MD toxicity. The experimental groups were: rats treated with corn oil (control group), rats treated with 5 mg/kg MD (MD), and rats treated with 5 mg/kg body weight MD plus vitamin E and vitamin C (MD+Vit). The groups were given MD by gavage on 5 days a week for 4 weeks at a daily dose 5 mg/kg (MD and MD+Vit) using corn oil as the vehicle. Vitamins E and C were injected at doses of 50 mg/kg intramuscularly and 20 mg/kg intraperitoneally, respectively, after the treatment with MD in the MD+Vit group. The levels of malondialdehyde (MDA) were determined in the aortic tissue. Histopathological examination was examined in the thoracic aortic tissue. MDA levels were higher in the MD group than the control group and lower in the MD+Vit group than MD group. MD administration led to irregulation, prominent breaks, and fragmentation of the elastic fibers but decrease in the irregulation and fragmantation of the elastic fibers with the combination of vitamins E and C in MD-treated rats. In conclusion, it is likely that subacute MD administration caused vascular wall damage, and that treatment with a combination of vitamins E and C after the administration of MD can reduce vascular wall damage caused by MD.

Administration, Oral↗
PubMed2004

The role of free oxygen radicals on the development of otitis media with effusion.

OBJECTIVE: The purpose of this study was to determine if free oxygen radicals (FORs) and antioxidant enzyme activities have some role in pathogenesis of otitis media with effusion (OME) in children with adenoid hyperplasia. METHODS: Seventy-four patients were enrolled in three groups of this study. The study group (Group I) included 26 patients who had adenoidectomy with ventilation tube placement due to chronic OME. The control adenoid group (Group II) consisted of 28 age-matched patients who had adenoidectomy without ventilation tube insertion. Twenty children were included in the healthy control group (Group III). Erythrocyte malondialdehyde (MDA) levels, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) enzyme activities were investigated in the venous blood sample. RESULTS: Erythrocyte MDA level and GSH-Px enzyme activity in the blood samples of study group (Group I) were significantly higher than those of Group II and Group III (P < 0.05). SOD enzyme activity in the blood samples of Group I was significantly lower than Group II (P < 0.05), and were significantly higher than Group III (P < 0.05). CAT enzyme activity of Group I was significantly lower than that of Group III (P < 0.05). However, there was no statistically significant difference between Group I and Group II regarding CAT antioxidant enzyme activity (P < 0.05). CONCLUSIONS: The inflammation of the middle ear increases the level of FORs in erythrocyte. FOR level is normally maintained at a steady state by antioxidant enzymes. When the antioxidant defense system is weakened, the increased FORs may contribute to OME formation. We supposed that, antioxidant vitamins C and E, and scavenger enzymes such as CAT, SOD and GSH-Px may be added in the management of OME.

Adenoidectomy↗
PubMed2004

NMDA receptor subunits 2A and 2B decrease and lipid peroxidation increase in the hippocampus of streptozotocin-diabetic rats: effects of insulin and gliclazide treatments.

Recent studies indicate that diabetes mellitus changes N-methyl-D-aspartate (NMDA) receptor subunit composition and impairs cognitive functions. It also has been known that diabetes mellitus causes lipid peroxidation. This study examined the effects of streptozotocin-diabetes and insulin or gliclazide treatment on the hippocampal NMDA receptor subunit 2A and 2B (NR2A and NR2B) concentrations. In addition, malondial dehyde (MDA) levels were measured as a marker for lipid peroxidation. Eight weeks after the induction of diabetes MDA, levels were increased, and NR2A and NR2B concentrations were reduced. Insulin and gliclazide treatment partially prevented the reduction of NR2A and NR2B expression and prevented the elevation of MDA levels. There was no significant difference between the effects of insulin and gliclazide. The results suggest that the elevation of lipid peroxidation can be the primary biochemical disturbances in diabetes progression, and that changes in NMDA receptor subunit compositions can be involved in cognitive decline in diabetes.

Animals↗
PubMed2004

Effects of dietary long chain PUFAs on hippocampal lipid peroxidation and NMDA receptor subunits A and B concentration in streptozotocin-diabetic rats.

This study examined the effects of streptozotocin (STZ)-diabetes and dietary long chain polyunsaturated fatty acids (LC-PUFAs) on hippocampal N-methyl-D-aspartate (NMDA) receptor subunit expression and lipid peroxidation. MDA level was significantly increased after 8 weeks of STZ-diabetes. LC-PUFAs administration significantly reduced MDA levels in diabetic rats. NR2A and NR2B protein concentrations were significantly decreased by about 30% in diabetic rats. Dietary LC-PUFAs partially restored NR2A and NR2B in diabetic rats whereas the most significant increase was seen in nondiabetic rats. Consequently, dietary LC-PUFAs can partially restore hippocampal NMDA receptors and decrease lipid peroxidation in diabetes. LC-PUFAs are thus a possible prophylactic means for preventing the cognitive deficiencies of diabetes.

Animals↗