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Featured researches published by Omer Gunal.


Digestive Diseases and Sciences | 1996

Gastric functions in portal hypertension : Role of endothelin

Omer Gunal; Cumhur Yegen; A. Özdemir Aktan; Rifat Yalin; Berrak Ç. Yeğen

This study investigated the effects of portal hypertension on gastric motor and secretory functions and the role of endothelin in rats. Control; sham-operated; endothelin-A receptor blocker, BQ 485 (1 µg/kg) -treated; portal hypertensive; and portal hypertension +, endothelin-A receptor blocker-treated rats were subjected to tests of gastric secretory, motor, and mucosal function studies as well as gastric wall polymorphonuclear infiltration. Portal hypertension was induced by partial portal vein ligation. Portal hypertension suppressed gastric acid and total fluid secretion and delayed gastric emptying. An increase in mucosal permeability and no alteration in gastric wall myeloperoxydase activity were observed. The effects of portal hypertension on gastric secretory, motor, and mucosal functions were reversed by treatment with endothelin-A receptor blocker, BQ-485. It is concluded that portal hypertension suppresses the gastric motor and secretory functions and endothelin plays an important role in the pathophysiology of gastric alterations associated with portal hypertension.


Prostaglandins Leukotrienes and Essential Fatty Acids | 1997

Captopril prevents the oxidative damage to proteins after renal ischemia reperfusion injury : role of endothelin-1

Omer Gunal; A. Özdemir Aktan; Cumhur Yegen; Hizir Kurtel; Rifat Yalin

Ischemia reperfusion (I/R) injury is one of the leading cause of the transplanted organ loss. In this experimental study, we investigated the effect of captopril on endothelin and eicosanoid release in I/R injury of the kidney. Rats were subjected to 60 min ischemia and 60 min of reperfusion of the left kidney in control and captopril groups. Tissue protein oxidation products, PGE2 and LTB4 levels and plasma endothelin-1 (ET-1) like activity were determined in sham operated, control and captopril groups. There were no differences in the LTB4 levels among the groups. ET-1 and PGE2 levels and protein oxidation products increased in the control group when compared with the sham. Captopril further increased both PGE2 and ET-1 concentrations and prevented protein oxidation. The increased ET-1 concentrations in the captopril treated group may imply the protective role of endothelin as the significant increase in protein oxidation products was reversed by captopril infusion. This has led us to believe that captopril might be useful in preventing I/R injury of the kidney. Also the release of endothelin from the vascular endothelium is increased by captopril and may be mediated by PGE2.


Journal of The Korean Society of Coloproctology | 2013

Prognostic Impact of the Metastatic Lymph Node Ratio on Survival in Rectal Cancer

Wafi Attaallah; Omer Gunal; Manuk Manukyan; Gülden Özden; Cumhur Yegen

Purpose Lymph-node metastasis is the most important predictor of survival in stage III rectal cancer. The number of metastatic lymph nodes may vary depending on the level of specimen dissection and the total number of lymph nodes harvested. The aim of this study was to evaluate whether the lymph node ratio (LNR) is a prognostic parameter for patients with rectal cancer. Methods A retrospective review of a database of rectal cancer patients was performed to determine the effect of the LNR on the disease-free survival (DFS) and the overall survival. Of the total 228 patients with rectal cancer, 55 patients with stage III cancer were eligible for analysis. Survival curves were estimated using the Kaplan-Meier method. Cox regression analyses, after adjustments for potential confounders, were used to evaluate the relationship between the LNR and survival. Results According to the cutoff point 0.15 (15%), the 2-year DFS was 95.2% among patients with a LNR < 0.15 compared with 67.6% for those with LNR ≥ 0.15 (P = 0.02). In stratified and multivariate analyses adjusted for age, gender, histology and tumor status, a higher LNR was independently associated with worse DFS. Conclusion This study showed the prognostic significance of ratio-based staging for rectal cancer and may help in developing better staging systems. LNR 0.15 (15%) was shown to be a cutoff point for determining survival and prognosis in rectal cancer cases.


Diseases of The Colon & Rectum | 2014

Should we consider topical silver nitrate irrigation as a definitive nonsurgical treatment for perianal fistula

Wafi Attaallah; Davut Tuney; Bahadir M. Gulluoglu; M. Umit Ugurlu; Omer Gunal; Cumhur Yegen

BACKGROUND: Surgery is currently the sole treatment modality for anal fistulas. However, surgery is associated with complications such as permanent incontinence, which reduces quality of life. OBJECTIVE: To determine the rate of complete clinical healing of anal fistulas after irrigation of the fistula tract with silver nitrate solution as a nonsurgical treatment. DESIGN: Prospective single arm study. SETTING: Tertiary university hospital PATIENTS: Adult patients with symptomatic perianal fistula presenting between June 2012 and January 2013. INTERVENTION: Irrigation of the fistula tract with 1% silver nitrate solution. Irrigation was repeated every 2 weeks when necessary. MAIN OUTCOME MEASURES: The primary outcome measure was the rate of complete clinical healing. RESULTS: Fifty-six consecutive patients with anal fistula were analyzed. Of those, 29 (52%) had complete clinical healing without recurrence for a median of 10 months. The median number of irrigations needed for complete clinical healing was 4 (1–10). The level of satisfaction was excellent in patients with complete clinical healing. The frequency of complaints was the only independent factor that had an impact on healing; patients with intermittent discharge had a significantly higher rate of complete clinical healing (67%) than those with continuous discharge (40%). There were no notable complications. LIMITATIONS: Short follow-up, small sample size, and no comparisons. CONCLUSION: This study demonstrates that the application of silver nitrate solution often produces a favorable outcome in the treatment of anal fistula. This method may be considered as a first-line treatment for the disease because it is simple, performed on an outpatient basis, minimally invasive, and lacks the complications encountered with current conventional surgical modalities.


Journal of the Pancreas | 2014

Endoscopic snare excision of adenoma of the papilla of Vater without prophylactic pancreatic-duct stent.

Wafi Attaallah; Omer Gunal; Sina Mokhtare; Tolga Özmen; Asım Cingi

CONTEXT The endoscopic excision of adenomas of the papilla of Vater has gained increased popularity in the recent years. Temporary pancreatic drainage has been advised to accompany snare papillectomy in order to prevent ductal obstruction and serious pancreatitis. OBJECTIVES We evaluated treatment outcome of patients who had undergone endoscopic papillectomy without pancreatic drainage. METHODS Three consecutive adult patients with adenomas of the papilla of Vater presented with jaundice and pain were treated by endoscopic snare excision between October 2013 and February 2014 in a single center. ERCP procedures revealed papillary tumors and endoscopic biopsy specimens revealed tubular adenoma the papilla of Vater. Adenomas were treated by snare papillectomy method and a biliary stent was inserted as a prophylactic procedure immediately after excision of the adenoma in each case. In addition to physical examination, laboratory tests were repeated in the follow-up period after papillectomy in order to document if there is any complication particularly pancreatitis. RESULTS None of the patients experienced an immediate complication, including pancreatitis after papillectomy. Also neither patient experienced abnormal fluctuations of laboratory tests during the follow-up. Histopathologic evaluation of the resection specimens revealed a tubular adenoma with low grade dysplasia in the first two patients and a tubular adenoma with high-grade dysplasia in the third one. Endoscopy and pathologic evaluation revealed no recurrent/residual disease during the follow-up period of these patients. CONCLUSION Endoscopic snare resection of adenoma of the major papilla of the duodenum is a safe and minimal invasive alternative to surgical therapy. Biliary stent is sufficient to prevent biliary ductal patency and pancreatic stenting might not be necessary to prevent pancreatitis.


Journal of Hepato-biliary-pancreatic Surgery | 1995

Low incidence of deep venous thrombosis after laparoscopic cholecystectomy

A. Özdemir Aktan; Omer Gunal; Tuĝrul Bíren; Cumhur Yeĝen; Rifat Yalin

The effects of the increased intraabdominal pressure that occurs during laparoscopic cholecystectomy and the effects of the reverse Trendelenburg position adopted for the procedure on deep venous thrombosis (DVT) were investigated prospectively. Thirty patients who underwent laparoscopic and 13 who underwent open cholecystectomy for symptomatic cholelithiasis were investigated for postoperative DVT. Lower extremity venous blood flow was examined by color Doppler ultrasonography before and after operations. Thrombus formation was not found in the femoral, popliteal, or iliac veins of any of the patients who underwent either open or laparoscopic cholecystectomy. None of the patients in either group displayed signs of DVT or pulmonary embolus. We concluded that the incidence of DVT does not increase with laparoscopic cholecystectomy.


BioScience Trends | 2017

Simultaneous resection for colorectal cancer with synchronous liver metastases is a safe procedure: Outcomes at a single center in Turkey

Ender Dulundu; Wafi Attaallah; Metin Tilki; Cumhur Yegen; Safak Coskun; Mümin Coşkun; Aylin Erdim; Eda Tanrikulu; Samet Yardimci; Omer Gunal

The optimal surgical strategy for treating colorectal cancer with synchronous liver metastases is subject to debate. The current study sought to evaluate the outcomes of simultaneous colorectal cancer and liver metastases resection in a single center. Prospectively collected data on all patients with synchronous colorectal liver metastases who underwent simultaneous resection with curative intent were analyzed retrospectively. Patient outcomes were compared depending on the primary tumor location and type of liver resection (major or minor). Between January 2005 and August 2016, 108 patients underwent simultaneous resection of primary colorectal cancer and liver metastases. The tumor was localized to the right side of the colon in 24 patients (22%), to the left side in 40 (37%), and to the rectum in 44 (41%). Perioperative mortality occurred in 3 patients (3%). Postoperative complications were noted in 32 patients (30%), and most of these complications (75%) were grade 1 to 3 according to the Clavien-Dindo classification. Neither perioperative mortality nor the rate of postoperative complications after simultaneous resection differed among patients with cancer of the right side of the colon, those with cancer of the left side of the colon, and those with rectal cancer (4%, 2.5%, and 2%, respectively, p = 0.89) and (17%, 33%, and 34%, respectively; p = 0.29)]. The 5-year overall survival of the entire sample was 54% and the 3-year overall survival was 67 %. In conclusion, simultaneous resection for primary colorectal cancer and liver metastases is a safe procedure and can be performed without excess morbidity in carefully selected patients regardless of the location of the primary tumor and type of hepatectomy.


Turkish Journal of Surgery | 2016

Laparoscopic resection for colorectal diseases: short-term outcomes of a single center

Wafi Attaallah; Hayyam Babayev; Samet Yardimci; Asım Cingi; Mustafa Umit Ugurlu; Omer Gunal

OBJECTIVE Even though, laparoscopy is not accepted as the current gold standard in colorectal surgery, it can be performed as safely as open surgery. It is also widely accepted that the technique has many advantages. In this study, we evaluated the results of 33 patients with laparoscopic colorectal resection. MATERIAL AND METHODS Thirty-three patients who underwent laparoscopic colon surgery between January 2013 and September 2014 in the General Surgery Clinic at Marmara University Hospital were included in the study. Patients were evaluated in terms of their demographic and tumor histopathologic characteristics, type of surgery and early postoperative complications. RESULTS Laparoscopic colorectal resection was performed for 33 patients who had malignant or benign lesions. The median age was 60 (35-70), and 18 (55%) were male patients. The majority of the patients (90%) were diagnosed with colorectal adenocarcinoma. Half of the patients were T3 and 67% had N0 stage. The median number of retrieved lymph nodes was 17 (4-28). Negative surgical margins were obtained in all patients. The postoperative hospital stay was 5 (4-16) days. Postoperative early complications were observed in only 5 patients. The majority of complications were treated without the need for surgery. No mortality was recorded in this series of patients. CONCLUSION This study showed that laparoscopic colorectal surgery could be performed safely based on its low complication rate, short length of hospital stay, providing sufficient surgical resection and lymph node dissection.


Indian Journal of Surgical Oncology | 2016

Prognostic Impact of the Metastatic Lymph Node Ratio on Survival in Gastric Cancer

Wafi Attaallah; Kivilcim Uprak; Omer Gunal; Cumhur Yegen


Surgical Endoscopy and Other Interventional Techniques | 2016

Do not rush for surgery; stent placement may be an effective step for definitive treatment of initially unextractable common bile duct stones with ERCP

Wafi Attaallah; Asım Cingi; Sakir Karpuz; Mehmet Karakus; Omer Gunal

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