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    Alteration of nitric oxide production in rats exposed to a prolonged, extremely low-frequency magnetic field
    (Taylor & Francis Inc, 2007) Akdag, M. Zulkuf; Bilgin, M. Hakki; Dasdag, Suleyman; Tumer, Cemil
    The purpose of this stud), is to investigate the possible effect of an extremely low frequency magnetic field (ELF-MF) on nitric oxide (NO) level. In this study, 27 male Sprague-Dawley rats were used. The rats were divided into three groups: two experimental and one control (sham-exposed). The first and second experimental group (n = 10) were exposed to 100 mu T and 500 mu T ELF-MF during 10 months, 2 h a day, respectively, and the third (n = 7) group was treated like an experimental group except for ELF-MF exposure in methacrylate boxes. After ELF-MF and sham exposure, serum nitrite levels were measured by Griess reaction. A significant reduction was observed in nitrite levels among the first and second experimental groups of rats and sham-exposed rats after exposure for 10 months, 2 h a day, to ELF-MF of 100 and 500 LT (p < 0.01). These results suggest that prolonged ELF-MF exposure at intensities of exposure limits, determined by ICNIRP for public and occupational, may reduce NO production probably affected by NO generation pathways.
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    Anticonvulsive and behavior modulating effects of sophoretin and rutoside
    (Akademiai Kiado Zrt, 2019) Demir, Enver Ahmet; Ozturk, Atakan; Tutuk, Okan; Dogan, Hatice; Tumer, Cemil
    Introduction: Seizures are the hallmarks of most types of epilepsies. Behavioral and cognitive impairments coincide with interictal periods even though it is not clear whether these impairments spring out of the seizure itself or accompanying sociopsychological burden of the disease. Materials and methods: In this study, we investigated behavioral and cognitive consequences of a single GABA receptor-related seizure in mice, and examined the potential anticonvulsive and behavior-modulating properties of sophoretin (quercetin) and rutoside (rutin). Results: The study demonstrated that sophoretin and rutoside, common flavonoids of the human diet, delay the seizure onset and reduce the seizure stage. Moreover, they exerted an antidepressant-like effect, which was independent of the seizure. Neither treatments nor seizure altered recognition and spatial memory performances of the mice. Conclusions: Behavioral or cognitive disturbances that are evident in epileptic patients did not appear following a single seizure. In addition, we suggest that both sophoretin and rutoside successfully alleviate the seizure severity without interfering in the behavioral stability and cognitive performance. Hence, these flavonoids may be of use as adjuncts to the current treatment options.
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    The association of endothelial nitric oxide synthase gene G894T polymorphism and serum nitric oxide concentration with microalbuminuria in patients with gestational diabetes
    (Dustri-Verlag Dr Karl Feistle, 2014) Atay, Ahmet Engin; Akbas, Halit; Tumer, Cemil; Sakar, Mehmet Nafi; Esen, Bennur; Incebiyik, Adnan; Simsek, Selda
    Aim: Gestational diabetes mellitus (GDM) is a glucose intolerant condition that affects 14% of all pregnancies. Diabetes mellitus (DM) occurs in 30 - 70% of patients with GDM after delivery. DM and GDM are associated with structural and functional deterioration of the renovascular system. Our aim is to investigate the association Glu-298Asp polymorphism of the endothelial nitric oxide synthase (eNOS) gene with serum nitric oxide levels and microalbuminuria in patients with GDM and healthy pregnancies. Material and methods: Serum nitric oxide (NO) levels, urinary excretion of albumin and Glu298Asp polymorphism of the eNOS gene were analyzed in 68 patients with GDM and 73 healthy controls. High performance liquid chromatography (HPLC-Griess) method was used to analyze serum NO levels. Microalbuminuria was evaluated by rate nephelometry method. The Glu298Asp polymorphism of the eNOS gene was determined by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). Results: Nitric oxide, glucose, creatinine, and microalbuminuria were significantly different between the patients and the control subjects (p = 0.001, p = 0.001, p = 0.002, and p = 0.005, respectively). There was a significant difference between groups in terms of the ratio of GG/GT+TT of eNOS gene Glu298Asp (p = 0.02). The patients with GT+TT genotype had significantly higher microalbuminuria levels and lower NO concentrations (22.16 vs. 9.51, p = 0.005, and 10.56 vs. 12.73, p = 0.021, respectively). The presence of T allele of eNOS gene is an independent predictor of microalbuminuria (OR: 2.346, 95% confidence interval: 1.247 - 5.238, p = 0.02) as well as serum glucose and NO concentration. Conclusion: The G894T polymorphism of eNOS gene and decreased NO concentration seem to be independent predictors of increased urinary excretion of albumin in patients with GDM. Determining the frequency of eNOS gene G894T polymorphism may help to identify pregnancies at increased risk of microalbuminuria.
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    Effect of ghrelin administration on phagocytic activity in acute cold-restraint stress exposed rats
    (Elsevier, 2007) Tumer, Cemil; Bilgin, Hakki Murat; Obay, Basra Deniz; Diken, Huda; Tasdemir, Ezel; Sermet, Abdurrahman
    Ghrelin, an endogenous ligand for growth hormone secretagogue receptor, was identified in the rat stomach. This peptide acts through nitric oxide (NO) by expressing endothelial nitric oxide synthase (eNOS) and down regulating inducible nitric oxide synthase (NOS) at its gastroproprotective effect against restraint stress induced damage. Recently the glirelin receptor has also been detected in peripheral systems including immune tissue. We have investigated the possible effect of glirelin on phagocytic activity of peritoneal macrophages in acute coldrestraint stress (ACRS) exposed rats. The rats were divided into control, stress and ghrelin groups. In ghrelin groups, single dose and three days consecutive dose of ghrelin (20 mu g/kg. i.p.) were applied to rats that were exposed to ACRS for 4 h. I rut of saline was injected i.p. after ACRS for 3 consecutive days to the rats of the stress groups. Ghrelin administration reduced the increased phagocytic activity induced by ACRS. We conclude that ghrelin exerts an important role at macrophage phagocytic activity in ACRS exposed rats. (c) 2006 Elsevier B.V. All rights reserved.
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    Effect of ghrelin on gastric myoelectric activity and gastric emptying in rats
    (Elsevier, 2008) Tumer, Cemil; Oflazoglu, Hueda Diken; Obay, Basra Deniz; Kelle, Mustafa; Tasdemir, Ezel
    Ghrelin is a recently discovered peptide in the endocrine cells of the stomach, which may stimulate gastric motility via the vagal nerve pathway. However, the mechanism of ghrelin-induced changes in gastrointestinal motility has not been clearly defined. The purpose of this study was to investigate the pharmacological effects of ghrelin on gastric myoelectrical activity and gastric emptying in rats, and to investigate whether cholinergic activity is involved in the effects of ghrelin. The study was performed on Sprague-Dawley rats implanted with serosal electrodes for electrogastrographic recording. Gastric slow waves were recorded from fasting rats at baseline and after injection of saline, ghrelin, atropine, or atropin+ghrelin. Gastric emptying of non-caloric liquid was measured by the spectrophotometric method in conscious rats. Intravenous administration of rat ghrelin (20 mu g/kg) increased not only dominant frequency, dominant power and regularity of the gastric slow wave but also the gastric emptying rate when compared with the control rats (P < 0.01, P < 0.05, P < 0.05, P < 0.001 respectively). These stimulatory actions of ghrelin on both gastric myoelectrical activity and gastric emptying were not fully eliminated by pretreatment with atropine sulphate. These results taken together suggest that ghrelin may play a physiological role in the enteric neurotransmission controlling gastric contractions in rats. (c) 2007 Elsevier B.V. All rights reserved.
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    Effect of nitric oxide on phagocytic activity of lipopolysaccharide-induced macrophages
    (Wiley, 2007) Tumer, Cemil; Bilgin, Hakki Murat; Obay, Basra Deniz; Diken, Huda; Atmaca, Mukadder; Kelle, Mustafa
    Among the antimicrobial mechanisms associated with macrophages, NO produced by iNOS plays a major role in intracellular killing, but the relationship between NO and phagocytic activity after injection of inflammatory agents into the peritoneal cavity is not clear. The aim of the present study was to investigate the effect of nitric oxide (NO) on macrophage function after treatment with intraperitoneal lipopolysaccharide (LPS) and the role of exogenous L-arginine administration in this event. Six experimental groups and one control group, each consisting of seven Wistar rats were used: Group I: Control; Group II: LPS; Group III: LPS + L-arginine; Group IV: LPS + L-arginine + Aminoguanidine; Group V: LPS + Aminoguanidine; Group VI: L-arginine; Group VII: Aminoguanidine. Macrophage phagocytic activity and total plasma nitrite levels were increased in the LPS group. In the LPS + L-arginine group, both the phagocytic activity and total plasma nitrite levels showed large increases. Administration of aminoguanidine (AG), a specific iNOS inhibitor, abolished macrophage phagocytic activity and total plasma nitrite levels in the LPS and LPS + L-arginine groups. As a result, we showed that NO produced by macrophages has a role not only in intracellular killing, but also in phagocytic activity. (c) 2006 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.
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    Prothrombin Time, Activated Thromboplastin Time, Fibrinogen and D-Dimer Levels and von-Willebrand Activity of Patients with Sheehan's Syndrome and the Effect of Hormone Replacement Therapy on These Factors
    (Akad Doktorlar Yayinevi, 2010) Pasa, Semir; Altintas, Abdullah; Tumer, Cemil; Demircin, Mustafa; Cil, Timucin; Bayan, Kadim; Danis, Ramazan
    Increased mortality due to atherosclerotic cardiovascular disease has been described in adult patients with hypopituitarism, although the precise underlying mechanisms remain undetermined. Various abnormalities of coagulation and fibrinolysis occur in patients with thyroid diseases. Conversely, there are conflicting reports concerning the effects of growth hormone replacement on coagulation and fibrinolytic pathways in hypopituitary adults, and there is no existing data on the effects of hypocortisolism on thrombotic and fibrinolytic systems. The same controversial data were also obtained in studies which evaluate the effects of estrogen replacement therapy on cardiovascular events in post-menopausal women. The aim of this study was to investigate the effects of Sheehan's syndrome (SS), which is a common cause of hypopituitarism, on haemostatic factors and to assess the effects of L-thyroxin, prednisolone and conjugated estrogen / medroxyprogesterone acetate replacement on these factors. Prothrombin time (PT), activated thromboplastin time (aPTT), fibrinogen and D-dimer levels, and von-Willebrand factor (vWF) activity were compared among 32 patients with SS and 35 control subjects (CS) with similar age. A shorter PT and aPTT, higher fibrinogen and d-dimer levels, and similar vWF activity were determined in patients with SS as compared with CS. In addition, it was determined that hormone replacement treatment did not have a significant effect on coagulation parameters except the fibrinogen and d-dimer levels.
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    Serum nitric oxide levels and flow-mediated dilatation in patients with Sheehan syndrome and the effect of combination therapy consisting of L-thyroxine, prednisolone, and conjugated estrogen/medroxyprogesterone acetate
    (Elsevier Science Inc, 2008) Bahceci, Mithat; Pasa, Semir; Akay, Hatice O.; Tuzcu, Alpaslan; Tumer, Cemil; Gokalp, Deniz
    Baseline and stimulated nitric oxide (NO) levels were higher, whereas baseline arterial diameter, FMD-stimulated NO increment, and arterial dilatation ratio were lower in Sheehan syndrome (SS) patients than in control subjects. After combination therapy consisting of prednisolone, L-thyroxine, and conjugated estrogen, baseline and stimulated NO levels of SS remained as high, but FMID-stimulated NO, NO increment ratio, and arterial dilatation ratio increased with treatment. (Fertil Steril (R) 2008;89:995-7. (c) 2008 by American Society for Reproductive Medicine.)