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Dive into the research topics where Gökhan Önem is active.

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Featured researches published by Gökhan Önem.


Journal of Investigative Medicine | 2005

Effect of Diclofenac on Experimental Pleurodesis Induced by Tetracycline in Rabbits

Seyda Ors Kaya; Ferda Bir; Habip Atalay; Gökhan Önem; Faruk Onder Aytekin; Mustafa Saçar

Background and Objective Pleurodesis is a frequently preferred procedure in thoracic surgery, and many factors may affect the process. We aimed to determine whether the administration of systemic diclofenac sodium diminishes the effectiveness of the pleurodesis induced by intrapleural tetracycline in rabbits. Methods Twelve male New Zealand rabbits that received tetracycline 35 mg/kg intrapleurally were allocated into two groups. The first group (diclofenac group, n = 6) received 2 mg/kg diclofenac sodium intramuscularly for 10 days, and the second group (control group, n = 6) received acetaminophen 30 mg/kg orally for 10 days after the pleurodesis procedure. The rabbits were sacrificed after 28 days, and the pleural spaces were assessed grossly for evidence of pleurodesis and microscopically for evidence of fibrosis, inflammation, and collagenization. Results The mean macroscopic pleurodesis score of the diclofenac group was 2.16 ± 0.40 compared with 2.83 ± 0.40 in the control group (p = .027). The mean microscopic pleurodesis score of the diclofenac group was 2. 3 ± 1.03, whereas it was 3.5 ± 0.54 in the control group (p = .045). Conclusion The administration of diclofenac sodium for 10 days following tetracycline pleurodesis reduces the effectiveness of pleurodesis in rabbits.


Journal of Cardiac Surgery | 2006

Coronary Arterial Revascularization in an Adult with Congenitally Corrected Transposition of Great Arteries and Dextrocardia

Ahmet Baltalarli; Halil Tanriverdi; Ibrahim Goksin; Gökhan Önem; Oya Rendeci; Mustafa Saçar

Abstract  Objectives:Congenitally corrected transposition of great arteries with dextrocardia is an extremely rare lesion in adulthood. This group of patients does not live long enough for atherosclerotic coronary artery disease processes, because of existing comorbid anomalies. Methods: We report a 47‐year‐old man with isolated congenitally corrected transposition of great arteries, dextrocardia, and athersclerotic coronary artery disease. The patient underwent coronary artery revascularization with cardiopulmonary bypass. The free left internal mammary artery (LIMA) was grafted to the tiny left anterior descending artery (LAD), and the reversed saphenous vein Y graft was anastomosed to the posterior descending and posterolateral branches of the morphologic right coronary artery. Results: The patient recovered uneventfully. He is alive and well 24 months after the surgery. Conclusions: To our knowledge, the present case is the first congenitally corrected transposition of great arteries with dextrocardia treated with grafted coronary artery bypass. Early and full revascularization is very important for the systemic right ventricle exposed to a systemic workload. The vessel pathologies and technical details of this unusual case are discussed in this paper.


Advances in Therapy | 2006

Comparison of simultaneous antegrade/vein graft cardioplegia with antegrade cardioplegia for myocardial protection.

Gökhan Önem; Mustafa Saçar; Ahmet Baltalarli; Ali Vefa Özcan; Ercan Gürses; Hülya Sungurtekin

Antegrade cardioplegic delivery via the aorta ensures distribution of cardioplegic solution through open arteries, but distribution may not be adequate beyond a stenotic coronary artery. This potential problem can be overcome by direct delivery of cardioplegia via a vein graft. The purpose of this study was to compare simultaneous antegrade/vein graft cardioplegia with antegrade cardioplegia during coronary artery bypass surgery. Twenty patients were divided into 2 groups. In group 1, intermittent antegrade cardioplegia was provided (n=10). In group 2, intermittent antegrade cardioplegia was supplemented by antegrade perfusion of vein grafts after distal anastomoses were completed (n=10). Data on enzyme release and hemodynamics were obtained preoperatively, before the induction of anesthesia, just before cross-clamping, immediately after aortic unclamping, and at 1, 6, 12, 24, and 48 h after unclamping. Enzyme release (creatinine phosphokinase-isoenzyme MB, cardiac troponin I, myoglobin) was similar in both groups (P > .05). Furthermore, no significant difference was noted in the incidence of postoperative low cardiac output syndrome, perioperative myocardial infarction, or ventricular arrhythmia (P > .05). In conclusion, both techniques permitted rapid postoperative recovery of myocardial function. Supplementation of antegrade perfusion of vein grafts with antegrade cold blood cardioplegia offered no advantage to study patients. However, hemostasis of a distal anastomosis may be controlled by this technique.


Journal of Surgical Research | 2009

Comparison of the therapeutic efficacy of linezolid and vancomycin and correlation of serum and tissue malondialdehyde and myeloperoxidase in an experimental mediastinitis model.

Suzan Sacar; Mustafa Saçar; Hülya Aybek; Huseyin Turgut; Gökhan Önem; Nural Cevahir; Zafer Teke; Ilknur Kaleli; Adem Güler; Alper Ucak; Ahmet Baltalarli

BACKGROUND We aimed to investigate the therapeutic efficacy of linezolid in an experimental mediastinitis model and to compare it with vancomycin, which is commonly used. The objective of this study was also to evaluate the role of the immune system in mediastinitis. MATERIALS AND METHODS Fifty adult Wistar rats were randomly divided into five groups: an uncontaminated and contaminated untreated control groups; a group that received sefazolin prophylaxis; and two groups treated with vancomycin or linezolid. Median sternotomy without access to pleural spaces was performed on all rats. All groups, except the uncontaminated one, were inoculated with 0.5 mL 10(8) colony-forming units/mL methicillin-resistant Staphylococcus aureus in the mediastinal and sternal layers. Postoperatively, vancomycin and linezolid groups were given antibiotic treatment for 7 d, starting 24 h after the end of the procedure. After 7-d treatment tissue samples from the upper ends of the sternotomy line and mediastinum were obtained and evaluated microbiologically. Additionally, serum, heart, lung, liver, kidney, and mediastinal tissues samples were obtained to determine malondialdehyde (MDA) and myeloperoxidase (MPO). RESULTS The study showed that either vancomycin or linezolid successfully reduced bacterial counts in mediastinum and sternotomy line. MDA and MPO levels were found to be decreased in the treated groups. There was a positive correlation between serum and tissues MDA and MPO in all of the groups. CONCLUSIONS Our study showed that linezolid appears to be a promising option for treating mediastinitis due to methicillin-resistant S. aureus. Additionally, it was demonstrated that a wide inflammatory process occurred after mediastinitis.


Journal of Artificial Organs | 2007

Neuraminidase produces a decrease of adherence of slime-forming Staphylococcus aureus to gelatin-impregnated polyester fiber graft fabric: an experimental study.

Mustafa Saçar; Gökhan Önem; Ahmet Baltalarli; Suzan Sacar; Huseyin Turgut; Ibrahim Goksin; Vefa Ozcan; Serhan Sakarya

Because slime-forming microorganisms are the major causative agents of graft infections, we aimed to investigate bacterial adherence in slime-forming and nonslime-forming Staphylococcus aureus and to determine the role of neuraminidase (NANase) on adherence to gelatin-impregnated polyester fiber graft fabric. An in vitro model was developed to quantitatively measure bacterial adherence to the surface of the graft. The grafts were divided into two groups – those colonized with slime-forming S. aureus and those colonized with nonslime-forming S. aureus. The grafts were put into sterile tubes and human plasma was instilled and incubated at 37°C to perform fibrin deposition on the grafts. After 48 h of incubation, grafts were drained and inoculated with slime-forming or nonslime-forming S. aureus in triptic soy broth in the presence or absence of NANase. Following 36 h of incubation at 36°C, grafts were vortexed and cultured to perform a colony count. Bacterial counts were expressed as total colony-forming units per square centimeter of graft. Slime-forming S. aureus had greater affinity with the graft compared with nonslime-forming S. aureus (P < 0.05). The adherence of slime-forming S. aureus was impaired by NANase treatment (P < 0.001) but NANase treatment of nonslime-forming S. aureus did not change the adherence to the graft (P > 0.05). These results show that slime plays an important role in the pathogenesis of vascular graft infection. Adherence of slime-forming S. aureus can be decreased by NANase treatment. This may have implications for the development of neuraminidase-embedded vascular grafts to diminish biomaterial-related infections.


Advances in Therapy | 2006

Neuraminidase decreases in vitro adherence of slime-forming coagulase-negative staphylococci to biosynthetic ovine collagen vascular graft

Gökhan Önem; Mustafa Saçar; Suzan Sacar; Serhan Sakarya; Huseyin Turgut; Ali Vefa Özcan; Ahmet Baltalarli

Vascular prosthetic graft infection is a major complication of vascular surgery that starts with adhesion of the microorganism to the graft. Because slime-forming microorganisms are the major causative agents in graft infection, the goals of investigators in this study were (1) to investigate the bacterial adherence of slime-forming and non-slime-forming coagulase-negative staphylococci (CNS), and (2) to determine the role of neuraminidase (NANase) in bacterial adherence to the biosynthetic ovine collagen graft. Human plasma was instilled and incubated at 37°C in preparation for fibrin deposition of grafts. After 48 hours, incubation grafts were drained and inoculated with slime-forming and non-slime-forming CNS in tryptic soy broth in the presence and in the absence of neuraminidase. After 24 hours of incubation at 36°C, grafts were vortexed and cultured for colony count. Bacterial counts were expressed as total colony-forming units per longitudinal centimeter of the graft. Slime-forming CNS had greater affinity to the collagen graft compared with non-slime-forming CNS (P < .05). Adherence of slime-forming CNS was impaired by NANase treatment (P < .001). NANase treatment of patients with non-slime-forming CNS did not change adherence to the graft (P > .05). Results show that slime plays an important role in the pathogenesis of vascular graft infection. Adherence of slime-forming CNS can be decreased through the administration of NANase. This may have implications for the development of neuraminidase-embedded vascular grafts designed to reduce the occurrence of biomaterial-related infection.


Asian Cardiovascular and Thoracic Annals | 1999

Late Effect of Mechanical Mitral Valve Diameter on Left Ventricular Function

Mert Kestelli; Rahmi Zeybek; Gökhan Önem; Ece Tonguç; Ahmet Baltalarli; Nursen Postaci; Riza Demir; Mansur Sagban

During left ventricular ejection, the minor (transverse) axis of the inner wall shortens by 27% to 37%, while the major axis shortens by 9%. Therefore, shortening of the minor axis accounts for 85% to 90% of the stroke volume and the mitral annulus area alters to assist left ventricular contraction. Mitral valve prostheses with large diameters are preferred but these may lead to systolic malfunction by restricting minor-axis shortening. We studied echocardiographic data of patients who has received mechanical mitral valves with the same inner diameter and opening angle but with different outer diameters (29 mm or 31 mm). Although there was no difference preoperatively in ejection fractions in the two groups, the postoperative ejection fraction was significantly higher in patients with the smaller valve. This finding indicates that mitral valve replacement with a prosthesis of large external diameter caused a deterioration in left ventricular function.


Journal of Pediatric Hematology Oncology | 2016

Fatal Pulmonary Embolism Due to Inherited Thrombophilia Factors in a Child With Wolfram Syndrome.

Kazım Küçüktaşçı; Serap Semiz; Yasemin Isik Balci; Tamer Özsari; Dolunay Gürses; Gökhan Önem; Mustafa Saçar; Füsun Düzcan; Doğangün Yüksel; Ender Semiz

Wolfram syndrome-1 is a rare and severe autosomal recessive neurodegenerative disease characterized by diabetes mellitus (DM), optic atrophy, diabetes insipidus, and deafness. Poorly controlled type 1 DM increases the risk for thrombosis. However, coexistence of DM and hereditary thrombosis factors is rarely observed. Here we present the case of a 13.5-year-old, nonfollowed girl newly diagnosed with poorly controlled Wolfram syndrome on the basis of the results of clinical and laboratory examinations. On the eighth day after diabetic ketoacidosis treatment, pulmonary embolism developed in the subject. Thrombus identified in the right atrium using echocardiography was treated by emergency thrombectomy. Homozygous mutation in the methylenetetrahydrofolate reductase gene C677T, heterozygous factor-V Leiden mutation, and active protein C resistance were identified in the patient. The patient was lost because of a recurring episode of pulmonary embolism on the 86th day of hospitalization. We present this case to highlight the need for investigating hereditary thrombosis risk factors in diabetic patients in whom thromboembolism develops.


Annals of Vascular Surgery | 2015

Rapidly Occurring Carotid Artery Aneurysm in a Patient with Behcet Disease

Tevfik Güneş; Gökhan Önem; Hayati Tastan; İhsan Alur

Behcet disease (BD) is a chronic systemic inflammatory disorder characterized by recurrent oral and genital ulcerations, üveitis, and skin lesions. Vascular system involvement is common in BD. Aneurysm formation appears to be more common than arterial occlusion. Extracranial carotid aneurysms in BD are extremely rare. In this report, we present rapidly expanding carotid pseudoaneurysm in a BD patient and its surgical treatment.


Surgical Practice | 2014

Selective carotid endarterectomy and the advantages of conventional and eversion endarterectomy

Bilgin Emrecan; Ahmet Coşkun Özdemir; Gökhan Önem

Selective carotid endarterectomy (SCE) is described as the extraction of atheromatous plaque through an arteriotomy made starting from the common carotid artery and extending to the external carotid artery. The aim of the present study was to report the initial experience of SCE technique at our department.

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