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Dive into the research topics where Zafer Teke is active.

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Featured researches published by Zafer Teke.


Journal of Surgical Research | 2008

Effects of Tempol, a Membrane-Permeable Radical Scavenger, on Local and Remote Organ Injuries Caused by Intestinal Ischemia/Reperfusion in Rats

Zafer Teke; Burhan Kabay; Akin Ozden; Cigdem Yenisey; Ferda Bir; Neşe Çallı Demirkan; Tuncay Bicakci; Ergun Erdem

BACKGROUND Tempol is a stable piperidine nitroxide of low molecular weight that permeates biological membranes and scavenges superoxide anions in vitro. In a variety of animal models, deleterious effects of reperfusion injury on both local and remote organs have been demonstrated. In this study, we aimed to investigate the effects of a membrane-permeable radical scavenger, Tempol, on local and remote organ injuries caused by intestinal ischemia/reperfusion (I/R) in rats. MATERIALS AND METHODS Male Wistar-albino rats were randomized into three groups: (I) Sham-operated control group, laparotomy without I/R injury (n = 12); (II) Intestinal I/R group, 60 min of ischemia by superior mesenteric artery occlusion followed by 2-h of reperfusion (n = 12); and (III) I/R + Tempol-treated group, identical to I/R group except for Tempol administration, 30 mg/kg bolus injection 5 min before reperfusion, followed by an infusion of 30 mg/kg/h intravenously (n = 12). Histopathologically, intestinal mucosal lesions were assessed by Chius classification, and pulmonary parenchymal damage was appraised by pulmonary neutrophil infiltration and acute lung injury scaling. Biochemically, myeloperoxidase activity, malondialdehyde, glutathione, and nitrite/nitrate (NO(x)) levels were determined in both intestinal mucosa and lung parenchyma. Evans blue dye concentration and organ wet/dry weight ratios were used as a marker of organ edema. Animal survival was observed up to 1 week. RESULTS Intestinal mucosal lesions and pulmonary parenchymal damage were significantly attenuated with Tempol treatment, histopathologically (P < 0.05). Tempol administration significantly reduced myeloperoxidase activity and malondialdehyde levels, and also significantly increased glutathione and NO(x) levels of both intestinal and lung tissues, biochemically (P < 0.05). Evans blue dye extravasation and wet/dry weight ratios of organs were significantly reduced with Tempol injection (P < 0.05). The survival rates of rats in Tempol-treated group were significantly higher than that of I/R-treated group (P < 0.05). CONCLUSIONS The present study suggests that Tempol administration significantly reduces both local and remote organ injuries caused by intestinal I/R before and throughout the reperfusion period. Further clinical studies are needed to clarify whether Tempol may be a useful therapeutic agent to use in particular operations where the reperfusion injury occurs.


American Journal of Surgery | 2008

Activated protein C attenuates intestinal reperfusion-induced acute lung injury : an experimental study in a rat model

Zafer Teke; Mustafa Saçar; Cigdem Yenisey; A. Ozgur Atalay; Tuncay Bicakci; Ergun Erdem

BACKGROUND Activated protein C (APC) is a serine protease with anticoagulant and anti-inflammatory activities. APC has been shown to attenuate local deleterious effects of ischemia/reperfusion (I/R) injury in many organs. We aimed to investigate the effects of APC on lung reperfusion injury induced by superior mesenteric occlusion. METHODS Male Wistar-Albino rats were allocated into 4 groups: (1) sham-operated group, laparotomy without I/R injury (n = 12); (2) sham + APC group, identical to group 1 except for APC treatment (n = 12); (3) intestinal I/R group, 60 minutes of ischemia followed by 3 hours of reperfusion (n = 12); and (4) I/R + APC-treated group, 100 microg/kg injection of APC intravenously, 15 minutes before reperfusion (n = 12). Evans blue dye was injected into half of the rats in all groups. We assessed the degree of pulmonary tissue injury by measuring activities of oxidative and antioxidative enzymes, as well as nitrate (NO(3)(-))/nitrite (NO(2)(-)) levels, biochemically. We evaluated acute lung injury (ALI) by establishing pulmonary neutrophil sequestration and ALI scoring histopathologically. Pulmonary edema was estimated by using Evans blue dye extravasation and wet/dry ratios. The plasma levels of proinflammatory cytokines and D-dimer were measured. RESULTS APC treatment significantly reduced activities of oxidative enzymes and nitrate/nitrite levels in the lung tissues, and plasma levels of proinflammatory cytokines and D-dimer, and also significantly increased activities of antioxidative enzymes (P < .05). Pulmonary neutrophil sequestration and ALI scores were decreased significantly with APC administration (P < .05). In addition, APC treatment significantly alleviated pulmonary edema (P < .05). CONCLUSIONS This study clearly showed that APC treatment significantly attenuated the lung reperfusion injury. Further clinical studies are required to clarify whether APC has a useful role in the reperfusion injury during particular surgeries in which I/R-induced organ injury occurs.


Journal of Laparoendoscopic & Advanced Surgical Techniques | 2010

Predictive Factors for Conversion to Open Surgery in Patients Undergoing Elective Laparoscopic Cholecystectomy

Metin Ercan; E. Birol Bostanci; Zafer Teke; Kerem Karaman; Tahsin Dalgic; Murat Ulas; Ilter Ozer; Yusuf B. Ozogul; Fuat Atalay; Musa Akoglu

BACKGROUND Laparoscopic cholecystectomy (LC) has become the standard surgical procedure for symptomatic gallbladder disease. The aim of this study was to identify factors that may be predictive of cases that would require a conversion to laparotomy. METHODS In the period of 2002-2007, 2015 patients who underwent elective LC were included in the study. Patients were divided into two groups. Group 1 (n = 1914) consisted of patients whose operation was successfully completed with LC. Group 2 (n = 101) consisted of patients who had a conversion. A prospective analysis of parameters, including patient demographics, laboratory values, radiologic data, and intraoperative findings, was performed. Multivariate stepwise logistic regression was used to determine those variables predicting conversion. RESULTS One-hundred and one (5.0%) patients required a conversion. Significant predictors of conversion to open cholecystectomy in univariate analysis were increasing age, male gender, previous upper abdominal or upper plus lower abdominal incisions, an elevated white blood cell count, high aspartate transaminase, alkaline phosphatase and total bilirubin levels, preoperative ultrasound findings of a thickened gallbladder wall and dilated common bile duct, preoperative endoscopic retrograde cholangiopancreatography (ERCP), high-grade adhesion, and scleroatrophic appearance of the gallbladder intraoperatively. Multivariate analysis revealed that a history of previous abdominal surgery, preoperative ERCP, high-grade adhesion, and scleroatrophic appearance of the gallbladder predicted conversion. CONCLUSIONS Patient selection is very important for efficient, safe training in LC. Based on the presented data, pathways could be suggested that enable the surgeon to precisely decide, during LC, when to convert to open surgery.


Surgery Today | 2006

Ectopic Pancreas of the Gastric Antrum Contiguous to a Gastrointestinal Stromal Tumor Manifesting as Upper Gastrointestinal Bleeding: Report of a Case

Zafer Teke; Burhan Kabay; Canan Kelten; Mustafa Yilmaz; Ender Duzcan

A 54-year-old woman was referred to us for investigation of recurrent episodes of melena. Gastroduodenal endoscopic examination revealed a hemorrhagic, polypoid tumor, about 3 cm in diameter, in the posterior wall of the gastric antrum, near the greater curvature. The lesion had a smooth surface with ulceration, and was fixed to the sublying planes. The source of the bleeding was the mucosa overlying the tumor. We performed a distal subtotal gastrectomy with Roux-en-Y anastomosis. Histopathological examination of the resected specimen revealed an ectopic pancreas and a gastrointestinal stromal tumor contiguous to the ectopic pancreatic tissue in the gastric antrum. The patient was discharged after an uneventful postoperative course and has not experienced any recurrence of symptoms since.


World Journal of Surgery | 2007

Pyrrolidine Dithiocarbamate Prevents Deleterious Effects of Remote Ischemia/Reperfusion Injury on Healing of Colonic Anastomoses in Rats

Zafer Teke; Faruk Onder Aytekin; Burhan Kabay; Cigdem Yenisey; Cagatay Aydin; Koray Tekin; Mustafa Saçar; Akin Ozden

BackgroundPyrrolidine dithiocarbamate (PDTC) is a low-molecular-weight thiol antioxidant and potent inhibitor of nuclear factor-κB (NF-κB) activation. It has been shown to attenuate local harmful effects of ischemia/reperfusion (I/R) injury in many organs. In recent animal studies, a delaying effect of remote organ I/R injury on the healing of colonic anastomoses has been demonstrated. In this study we investigated whether PDTC prevents harmful systemic effects of superior mesenteric I/R on left colonic anastomosis in rats.MethodsAnastomosis of the left colon was performed in 40 rats randomly allocated into the following four groups: (1) Sham-operated group (group I, n = 10)—simultaneously with colonic anastomosis, the superior mesenteric artery and collateral branches divided from the celiac axis and the inferior mesenteric artery were isolated but not occluded. (2) Sham+PDTC group (group II, n = 10)—identical to sham-operated rats except for the administration of PDTC (100 mg/kg IV bolus) 30 minutes prior to commencing the experimental period. (3) I/R group (group III, n = 10)—60 minutes of intestinal I/R by superior mesenteric artery occlusion. (4) PDTC-treated group (group IV, n = 10)—PDTC 100 mg/kg before and after the I/R. On postoperative day 6, all animals were sacrificed, and anastomotic bursting pressures were measured in vivo. Tissue samples were obtained for investigation of anastomotic hydroxyproline (HP) contents, perianastomotic malondialdehyde (MDA) levels, myeloperoxidase activity (MPO), and glutathione (GSH) level.ResultsThere was a statistically significant decrease in anastomotic bursting pressure values, tissue HP content and GSH level, along with an increase in MDA level and MPO activity in group III, when compared to groups I, II, and IV (p < 0.05). However, PDTC treatment led to a statistically significant increase in anastomotic bursting pressure values, tissue HP content and GSH level, along with a decrease in MDA level and MPO activity in group IV (p < 0.05).ConclusionsThis study showed that PDTC treatment significantly prevented the delaying effect of remote organ I/R injury on anastomotic healing in the colon. Further clinical studies are needed to clarify whether PDTC may be a useful therapeutic agent for increasing the safety of the anastomosis during particular operations where remote organ I/R injury occurs.


Journal of Investigative Surgery | 2010

Topical Ankaferd Application to Presacral Bleeding due to Total Mesorectal Excision in Rectal Carcinoma

Kerem Karaman; Erdal Birol Bostanci; Metin Ercan; Mevlut Kurt; Zafer Teke; Enver Reyhan; Musa Akoglu

Kerem Karaman, MD, Erdal Birol Bostanci, MD, and Metin Ercan, MD Department of Gastroenterological Surgery, Turkiye Yuksek Ihtisas Teaching and Research Hospital, Ankara, Turkey Mevlut Kurt, MD Department of Gastroenterology, Turkiye Yuksek Ihtisas Teaching and Research Hospital, Ankara, Turkey Zafer Teke, MD, Enver Reyhan, MD, and Musa Akoglu, MD Department of Gastroenterological Surgery, Turkiye Yuksek Ihtisas Teaching and Research Hospital, Ankara, Turkey


Tumori | 2008

Primary infiltrating ductal carcinoma arising in aberrant breast tissue of the axilla: a rare entity. Report of a case

Zafer Teke; Burhan Kabay; Metin Akbulut; Ergun Erdem

A 52-year-old woman presented with a palpable nodule in the right axilla. Physical examination revealed a 2.5 × 2.5 cm, nontender, firm, brownish, and peripherally hyperemic mass with overlying skin retraction on the right anterior axillary fold. Bilateral mammogram was negative. Ultrasonography of the right axillary region showed a 1.8 × 1.1 cm, poorly defined hypoechoic mass with irregular margins and posterior acoustic shadowing. Fine-needle aspiration biopsy of the mass revealed malignant epithelial cells. The patient underwent a wide local excision of the right axillary lesion with en bloc axillary lymph node dissection. Histopathological examination revealed an infiltrating ductal carcinoma. Here we report this case of carcinoma originating from aberrant breast tissue in the axilla. It is suggested that subcutaneous lesions of uncertain origin around the periphery of the breast should be suspected for breast carcinoma and treated appropriately.


Journal of Surgical Research | 2008

Activated protein C attenuates intestinal mucosal injury after mesenteric ischemia/reperfusion.

Zafer Teke; Mustafa Saçar; Cigdem Yenisey; A. Ozgur Atalay; Tulay Kavak; Ergun Erdem

BACKGROUND Activated protein C (APC) is a serine protease with anticoagulant and ant-inflammatory activities. APC has been shown to attenuate deleterious effects of ischemia/reperfusion (I/R) injury in many organs. In this study, we aimed to investigate the effects of APC on intestinal mucosal injury induced by superior mesenteric occlusion. MATERIALS AND METHODS Male Wistar-albino rats were allocated into four groups: (1) sham-operated group, laparotomy without I/R injury (n = 12); (2) sham + APC group, identical to Group 1 except for APC treatment (n = 12); (3) I/R group, 60 min of ischemia followed by 3-h of reperfusion (n = 12); and (4) I/R + APC-treated group, 100 mug/kg injection of APC intravenously, 15 min before reperfusion (n = 12). We evaluated the degree of intestinal mucosal injury on a grading scale from 0 to 5, histopathologically, and by measuring activities of oxidative and antioxidative enzymes as well as nitrate/nitrite levels, biochemically. Intestinal edema was estimated by using wet/dry weight ratios. The plasma levels of proinflammatory cytokines and D-dimer were measured. Animal survival was observed up to 1 wk. RESULTS Intestinal mucosal injury scores were significantly decreased with APC administration (P < 0.05). APC treatment significantly reduced activities of oxidative enzymes and nitrate/nitrite levels in the intestinal tissues, and plasma levels of proinflammatory cytokines and D-dimer, and also significantly increased activities of antioxidative enzymes in the intestinal tissues (P < 0.05). Intestinal edema was significantly alleviated with APC treatment (P < 0.05). The survival rate of rats in the APC-treated group were significantly higher than that of the I/R-treated group (P < 0.05). CONCLUSIONS This study clearly showed that APC treatment significantly attenuated intestinal mucosal injury caused by superior mesenteric ischemia/reperfusion. Further clinical studies are required to clarify whether APC has a useful role in reperfusion injury during particular surgeries in which I/R-induced organ injury occurs.


World Journal of Surgery | 2007

Effects of Pyrrolidine Dithiocarbamate on Healing of Colonic Anastomoses in the Cecal Ligation and Puncture Model of Intraperitoneal Sepsis in Rats

Zafer Teke; Faruk Onder Aytekin; Cagatay Aydin; Burhan Kabay; Cigdem Yenisey; Suzan Sacar; Nilufer Genc Simsek; Koray Tekin

IntroductionPyrrolidine dithiocarbamate (PDTC) is a low-molecular thiol antioxidant and potent inhibitor of nuclear factor-κB (NF-κB) activation. In recent animal studies, the delaying effect of intraperitoneal sepsis on healing of colonic anastomoses has been demonstrated. In this study, we aimed to investigate the effects of PDTC on healing of colonic anastomoses in the presence of intraperitoneal sepsis induced by a rodent model of cecal ligation and puncture (CLP).MethodsAnastomosis of the left colon was performed on the day following CLP in 30 rats that were divided into three groups: sham-operated control (laparotomy and cecal mobilization, group I, n =10), cecal ligation and puncture (CLP) (group II, n = 10), PDTC-treated group (100 mg/kg IV before construction of the colonic anastomosis) (group III, n = 10). On postoperative day 6, all animals were sacrificed, and anastomotic bursting pressures were measured in vivo. Tissue samples were obtained for further investigation of colonic anastomotic hydroxyproline (HP) contents, perianastomotic myeloperoxidase (MPO) activity, and malondialdehyde (MDA) and glutathione (GSH) levels.ResultsThere was a statistically significant increase in the activity of MPO and MDA levels in the CLP group (group II) along with a decrease in GSH levels, colonic anastomotic HP contents, and bursting pressure values when compared to controls (group I). However, PDTC treatment led to a statistically significant increase in the tissue HP contents, GSH levels, and colonic anastomotic bursting pressure values, along with a decrease in MPO activity and MDA levels in group III (p < 0.05).ConclusionsThis study showed that PDTC treatment significantly prevented the delaying effect of CLP-induced intraperitoneal sepsis on anastomotic healing in the colon. Further clinical studies are needed to clarify whether PDTC may be a useful therapeutic agent to increase the safety of the anastomosis during particular operations where sepsis-induced injury occurs.


Tumori | 2007

PRIMARY NEUROENDOCRINE CARCINOMA OF THE BREAST: A CASE REPORT

Arzu Yaren; Canan Kelten; Metin Akbulut; Zafer Teke; Ender Duzcan; Ergun Erdem

Primary neuroendocrine carcinoma of the breast is an extremely rare tumor. We present our experience of primary neuroendocrine carcinoma of the breast in a 76-year-old woman. Surgical biopsies from breast and axillary lymphadenopathy showed a neuroendocrine carcinoma. Immunohistochemical staining of tumor cells with GCDFP15, NSE and chromogranin were positive. Computed tomography scans of the chest and abdomen showed no lesion for metastasis or another primary origin. Adjuvant hormone therapy was given, since the tumor was immunohistochemically receptor positive.

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Musa Akoglu

University of Pittsburgh

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Cigdem Yenisey

Adnan Menderes University

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