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Dive into the research topics where Hakki Oktay Seymen is active.

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Featured researches published by Hakki Oktay Seymen.


Asian Journal of Surgery | 2011

Effects of clinoptilolite treatment on oxidative stress after partial hepatectomy in rats.

Kaya Saribeyoglu; Erman Aytac; Salih Pekmezci; Seha Saygili; Hafize Uzun; Gulsen Ozbay; Seval Aydin; Hakki Oktay Seymen

BACKGROUND/OBJECTIVE Clinoptilolite is a natural zeolite crystal. Cytoprotective effects of clinoptilolite have been reported. However, so far there are no data about the effects of clinoptilolite treatment on oxidative stress after partial hepatectomy. In this experimental study, the effects of clinoptilolite treatment after partial hepatectomy on oxidative stress were evaluated. METHODS There were four experimental groups (n=8): Group S, the sham group; Group H, the hepatectomy group; Group HC, the clinoptilolite treatment after partial hepatectomy group; and Group CS, the clinoptilolite-treated sham group. A 70% partial hepatectomy was performed for Group H and HC. Clinoptilolite (5mg/kg) was given to the rats orally (via gavage tube) twice a day for 10 days after hepatectomy. Malondialdehyde (MDA), Cu-Zn super oxide dismutase (SOD), and glutathione (GSH) levels were assessed to evaluate oxidative stress. RESULTS Plasma and liver tissue MDA levels of Group HC were significantly lower than the H group (p=0.018 and p=0.000, respectively). Liver tissue Cu-Zn SOD activity and GSH levels of Group HC were significantly higher than Group H (p=0.003, p=0.007, respectively). CONCLUSION Clinoptilolite administration reduces oxidant activity and supports antioxidant response after partial hepatectomy.


Transplantation Proceedings | 2009

Effects of Cyclosporine-Tacrolimus Switching in Posttransplantation Hyperlipidemia on High-Density Lipoprotein 2/3, Lipoprotein A1/B, and Other Lipid Parameters

P. Seymen; M. Yildiz; M.F. Türkmen; M.I. Titiz; Hakki Oktay Seymen

OBJECTIVE In renal transplant recipients, cyclosporine treatment appears to cause more frequent hyperlipidemia than tacrolimus usage. In this study, hyperlipidemic renal transplant recipients who use cyclosporine were investigated for changes in high-density lipoprotein (HDL)-2/3, apolipoprotein (Apo) A1/B, other lipid and biochemical parameters, and body mass index after prospective cyclosporine to tacrolimus switching. MATERIALS AND METHODS Fifteen patients, including 9 females of overall mean age of 33.2 +/- 10.7 years and posttransplantation time of 78.06 +/- 42.93 months with a mean body mass index of 23.77 +/- 3.34 kg/m(2), were included if they were nondiabetic, hyperlipidemic, and had undergone renal transplantation between 1992 and 2000, using cyclosporine and candidates for a switch to tacrolimus due to hyperlipidemia. Before switching to tacrolimus and at 12 months of tacrolimus use we studied fasting blood samples for creatinine, uric acid, glucose, triglyceride, Apo A1, Apo B, low-density lipoprotein (LDL), HDL2, HDL3, and total cholesterol. RESULTS There were no significant differences in creatinine, uric acid, glucose levels, or body mass index before tacrolimus versus 12 months thereafter. It was observed that tacrolimus significantly decreased triglyceride, Apo A1, Apo B, LDL, HDL, and total cholesterol levels (P < .001; P = .006; P = .01; P < .001; P = .03; P </= .001, respectively), but had no effect on homocysteine, Apo A1/B, HDL 2, HDL 3, or HDL 2/3 levels (P > .05). CONCLUSION Switching from cyclosporine to tacrolimus was associated with a more favorable cardiovascular risk profile by improving hyperlipidemia.


Prostaglandins Leukotrienes and Essential Fatty Acids | 2008

Donor heart preservation with iloprost supplemented St. Thomas Hospital cardioplegic solution in isolated rat hearts

Burcak Deniz Dedeoglu; Erman Aytac; Öner Süzer; Huriye Balci; Hafize Uzun; Pinar Seymen; Hakki Oktay Seymen

This study was designed to assess the influence of St. Thomas Hospital cardioplegic solution (St. Th.) on heart preservation in rat hearts subjected to 6h ischemia when supplemented with iloprost. In the control group (n=8), nothing was added to St. Th., whereas 10 or 1000 nmol L(-1) iloprost was added in the second (n=7) and third (n=8) groups, respectively. Mechanical contraction parameters, cardiac tissue damage and oxidative stress markers were evaluated. The 10 nmol/L iloprost group peak systolic pressure (71.0+/-30.9 versus 41.0+/-9.4 mm Hg) and -dp/dtmax (1103.8+/-94.3 versus 678.6+/-156.8 mm Hg s(-1)) were significantly higher than control group at 30 min of reperfusion (p<0.05). Iloprost supplemented groups had higher GSH and catalase levels of coronary perfusate at reperfusion, in comparison with initial values (p<0.05). AST, CK, CK-MB values increased at 0 min of reperfusion and cTnI values at 45 min of reperfusion (p<0.05) in all groups with no difference between groups. According to our results, iloprost supplementation had mild but significant improvement in postischemic values in mechanical and oxidative stress parameters, resulting in better heart preservation.


The Turkish journal of gastroenterology | 2015

Visual evoked potentials and pulse wave velocity in inflammatory bowel disease.

Erman Aytac; Deram Büyüktaş; Birol Baysal; Murat Atar; Mustafa Yildiz; Bilgi Baca; Tayfun Karahasanoglu; Aykut Ferhat Celik; Hakki Oktay Seymen; Ismail Hamzaoglu

BACKGROUND/AIMS Data about the effects of inflammatory bowel disease (IBD) on various functions of the nervous and cardiovascular systems are limited. In this study, the visual neuronal and cardiovascular functions of patients with IBD were evaluated by measuring visual evoked potentials (VEP) and pulse wave velocity (PWV), respectively. MATERIALS AND METHODS There were three study groups: the Crohns disease (CD) group (n=25), the ulcerative colitis (UC) group (n=30), and a healthy control (C) group (n=25). The exclusion criteria were as follows: patients with IBD were in remission, had no extra-intestinal manifestations of the disease, had no additional chronic disease(s), and had been receiving medical treatment for their IBD without any previous surgical intervention. VEP amplitudes (mV) and the N2 and P2 latencies (ms) were recorded for visual-neuronal analysis of all study groups. For cardiovascular assessment in all study groups, PWV was measured noninvasively as follows: the carotid-femoral PWV with the Complior Colson device (The authors have no conflict of interest.) and the PWV along the aorta with two ultrasound strain-gauge pressure-sensitive transducers (TY-306 Fukuda pressure-sensitive transducers - Fukuda Denshi Co, Tokyo, Japan) fixed transcutaneously over the course of a pair of arteries separated by a known distance. The right femoral and right common carotid arteries were the ones used. RESULTS The PWV levels of the CD and UC groups were significantly higher than those in the C group (p<0.001). In the bilateral recording of the VEP, the N2 latencies of the CD (p<0.05) and UC (p<0.01) groups were significantly longer than those in the C group. CONCLUSION In this study, we showed vascular and visual neuronal impairments at a subclinical stage in patients with both types of IBD.


Journal of Laryngology and Otology | 2002

Effect of Ringer-Lactate and isotonic saline solutions on mucociliary clearance of tracheal epithelium: an experimental study in rats.

Murat Ünal; Hakki Oktay Seymen

Isotonic saline solution is frequently used in nasal and tracheal lavage. In a previous clinical study, it was found that Ringer-Lactate solution, as a nasal lavage, was better for mucociliary clearance function than isotonic saline solution after nasal septal surgery. In this experimental study, the effects of Ringer-Lactate and isotonic saline solutions on mucociliary clearance of healthy rat tracheal epithelium were investigated by measuring the transport of carbon particles. We found that tracheal segments that were irrigated with Ringer-Lactate had better mucociliary transport than those irrigated with isotonic saline (p = 0.035).


International Journal of Neuroscience | 2012

Darbepoetin Alpha Ameliorates Neuronal Damage in a Rat Model of Acute Ethanol Intoxication

Pinar Seymen; Erman Aytac; Fehim Esen; Cigdem Tel; Fatih Demir; Habibe Genc; Hafize Uzun; Buge Oz; Tuncay Altug; Hakki Oktay Seymen

ABSTRACT Objective: Acute ethanol intoxication has been shown to cause oxidative damage in many organ systems including the brain. Erythropoietin has antioxidant effects and prevents neuronal damage in the animal model of ischemic brain injury. In this study, we aimed to investigate the effects of darbepoetin alpha, an analog of erythropoietin with a longer half-life and higher in vivo activity, on ethanol-induced acute brain injury. Methods: Forty-eight Wistar albino rats were allocated to four groups. The first group received ethanol treatment (E), the second group was treated with ethanol and darbepoetin (ED), the third group received only saline treatment (S), and the fourth group received both saline and darbepoetin treatment (SD). Plasma S100-β and neuron-specific enolase (NSE) levels were measured. Histopathological evaluation of the brains was performed. Results: The plasma S100-β and NSE levels were significantly lower in group ED compared with group E. In group E, we have observed focal red-neuron formation at the granular layer of the dentate gyrus. We did not observe any histopathological changes in the other groups (ED, S, and SD). Conclusion: Our findings suggest that darbepoetin alpha has neuroprotective effect in acute ethanol intoxication, possibly through its antioxidant effect.


Asian Journal of Surgery | 2008

Iloprost Pretreatment Before Unilateral Nephrectomy: An Experimental Study in Rats

Erman Aytac; Pinar Seymen; Goksel Dikmen; Hafize Uzun; Hakki Oktay Seymen

OBJECTIVE To evaluate the effects of iloprost administration before unilateral nephrectomy on postoperative interleukin-6 (IL-6), nitric oxide (NO), and oxidant/antioxidant status. METHODS Malondialdehyde, glutathione, catalase and Cu-Zn superoxide dismutase were measured in the blood and remnant kidney of Adult male Wistar albino rats to assess oxidant and antioxidant status. The rats were divided into three experimental groups: sham group (S) (n = 12); unilateral nephrectomized group (N) (n = 12); an hour before unilateral nephrectomy iloprost (1 ng/mL/kg, intraperitoneal) administered group (IN) (n = 12). RESULTS Iloprost administration before unilateral nephrectomy lowered oxidant parameters and IL-6 levels significantly. NO levels were increased in both N and IN groups. CONCLUSION Iloprost pretreatment before unilateral nephrectomy can reduce oxidative stress and IL-6, which increases due to anaesthesia and surgery and causes organ damage during surgery and in the short-term postoperative period.


Prostaglandins Leukotrienes and Essential Fatty Acids | 2006

Effects of iloprost on visual evoked potentials and brain tissue oxidative stress after bilateral common carotid artery occlusion

Erman Aytac; Hakki Oktay Seymen; Hafize Uzun; Goksel Dikmen; Tuncay Altug


Yonsei Medical Journal | 2004

Iron Supplementation in Experimental Hyperthyroidism: Effects on Oxidative Stress in Skeletal Muscle Tissue

Hakki Oktay Seymen; Sabiha Civelek; Arzu Seven; Günnur Yigit; Hüsrev Hatemi; Gülden Burçak


The Turkish journal of gastroenterology | 2011

Effects of lycopene on oxidative stress and remnant liver histology after partial hepatectomy in rats

Erman Aytac; Ayan F; Saygili S; Genç H; Karaca C; Bayrak I; Hafize Uzun; Salıhoğlu Z; Erdamar S; Altuğ T; Seymen P; Hakki Oktay Seymen

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