Demet Koc
Marmara University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Demet Koc.
Diseases of The Colon & Rectum | 2002
Rasim Gencosmanoglu; Orhan Şad; Demet Koc; Resit Inceoglu
PURPOSE: Hemorrhoidectomy is the treatment of choice for patients with third-degree or fourth-degree hemorrhoids. However, whether the closed or open technique yields better results is unknown. The purpose of this study was to compare these techniques with respect to operating time, analgesic requirement, hospital stay, morbidity rate, duration of inability to work, healing time, and follow-up results. METHODS: In this prospective and randomized study, 80 patients with third- degree or fourth-degree hemorrhoidal disease were allocated to either the open- hemorrhoidectomy (Group A, n = 40) or the closed-procedure group (Group B, n = 40). Open hemorrhoidectomy was performed according to the St. Mark’s Hospital technique, whereas the Ferguson technique was used for the closed procedure under general anesthesia with the patient in the jackknife position. RESULTS: Mean operating time was significantly shorter in Group A (35 ± 7 vs. 45 ± 8 minutes, P < 0.001). Analgesic requirement on the day of surgery and the first postoperative day was also significantly lower (P < 0.05). The morbidity rate was higher in Group B (P < 0.05). Length of hospital stay and duration of inability to work were similar in both groups (P > 0.05). Healing time was significantly shorter in Group B (2.8 ± 0.6 vs. 3.5 ± 0.5 weeks, P < 0.001). Median follow-up time was 19.5 (range, 4–40) months. The only late complication (anal stenosis) was observed in one patient in Group B. CONCLUSIONS: Although the healing time is longer, the open technique is more advantageous with respect to shorter operating time, less discomfort in the early postoperative period, and lower morbidity rate. Gençosmanoğlu R, Ŝad O, Koç D, İnceoğlu R. Hemorrhoidectomy: open or closed technique? A prospective, randomized clinical trial. Dis Colon Rectum 2002;45:70–75.
Journal of Gastroenterology | 2003
Rasim Gencosmanoglu; Demet Koc; Nurdan Tozun
A percutaneous endoscopic gastrostomy tube was inserted in a 59-year-old man who was undergoing craniotomy due to subarachnoid hemorrhage, because it was estimated that he could not have oral intake for a period of 4 weeks. Seventy days after the insertion, the percutaneous endoscopic gastrostomy tube was replaced because of its accidental removal by the patient. Two months after the second insertion, the tube had to be replaced due to nonfunctioning. The buried bumper syndrome was diagnosed on physical examination, and was confirmed by endoscopy, with findings of mucosal dimpling and nonvisualization of the internal bumper. The tube was removed by external traction without any abdominal incision, and the same site was used for the insertion of a replacement tube over a guidewire. The patient remained symptom-free during 18 months of follow-up.
Neurosurgery | 2010
Akin Akakin; Abdulkadir Ozkan; Emel Akgun; Demet Koc; Deniz Konya; M. N. Pamir; Turker Kilic
OBJECTIVETo compare the angiogenic potentials of embolized, gamma knife–treated or untreated cerebral arteriovenous malformations (AVMs), using a rat cornea angiogenesis model. METHODSTissue samples from cerebral AVM patients who were either untreated or had previously been treated with embolization or gamma knife radiosurgery and who had undergone operations for hemorrhage at the Neurosurgery Department or the Neurological Sciences Institute of Marmara University were used. For the macroscopic evaluation of angiogenesis, tissue samples were inoculated in a micropocket created on the rat eye, and the level of angiogenic activity was graded macroscopically for 15 days, with glioblastoma multiforme and normal brain artery tissues serving as positive and negative controls, respectively. For the other part of the experiment, eyes of another set of rats were inoculated with the study samples only using the same cornea angiogenesis model, in which microvessel count and vascular endothelial growth factor assessment was done at days 3, 7, 11, and 15. RESULTSBased on our macroscopic findings in the cornea angiogenesis model, embolized AVMs exhibited the highest angiogenic activity, followed by untreated AVMs and gamma knife–treated AVMs. Evaluations of vascular endothelial growth factor expression and microvessel counts showed a similar relation among the 3 tissue groups with regard to the level of angiogenic activity, supporting the results of macroscopic examinations. CONCLUSIONThis study, for the first time, provides experimental semiquantitative data to compare the angiogenic potentials of embolized and gamma knife–treated AVM tissues. Embolization may increase angiogenic activity, and gamma knife radiosurgery may decrease it when compared with activity in previously untreated AVMs. These data can be useful to understand why recurrence of AVMs after angiographically demonstrated endovascular occlusion is common but after gamma knife occlusion is rare.
Journal of Parenteral and Enteral Nutrition | 2007
Demet Koc; Arzu Gercek; Rasim Gencosmanoglu; Nurdan Tozun
BACKGROUND Even with a functioning gastrointestinal tract, it is not always easy to initiate oral feeding in some neurosurgical patients because of their persistently depressed neurologic status or severe lower cranial nerve palsies. Percutaneous endoscopic gastrostomy (PEG) may be required for long-term feeding in these patients. The purpose of the present study is to report our experience with PEG chosen for establishing an enteral route in patients of neurosurgical intensive care unit (ICU). METHODS The outcome and complications of PEG in neurosurgical ICU patients of Marmara University Institute of Neurological Science between January 2001 and November 2006 were retrospectively evaluated. RESULTS Thirty-one patients, with the median age of 51 years (range, 14-78 years) underwent PEG placement. PEG was placed before the craniotomy in 2 patients and after in 29. Indications for PEG were absent gag reflex in 10 patients and low Glasgow Coma Scale score in 21. Before the PEG tube insertion, 18 patients had enteral nutrition by a nasogastric tube and 10 had parenteral nutrition (PN), with a median duration of 14.5 (range, 4-60) and 12 (range, 7-25) days, respectively. Two patients accidentally pulled out the gastrostomy tubes 10 and 11 days after insertion. Buried bumper syndrome developed in 1 patient. Two patients died 8 and 34 days after the procedure in the neurosurgical ICU. Twenty-nine patients were discharged from the hospital while being fed via the PEG tubes. In 11 patients who were able to resume oral feeding, the tube was removed, with a median interval of 62 (range, 25-150) days. Procedure-related mortality, 30-day mortality, and overall mortality of the patients were 0%, 6.4%, and 45%, respectively. CONCLUSION PEG is a safe and well-tolerated gastrostomy method for neurosurgical ICU patients with depressed neurologic state or severe lower cranial nerve palsies.
Journal of Clinical Neuroscience | 2010
Atilla Bicer; Bulent Guclu; Abdulkadir Ozkan; Ozlem Kurtkaya; Demet Koc; M. Necmettin Pamir; Turker Kilic
This study aimed to compare cerebral arteriovenous malformations (cAVM) and cerebral cavernous malformations (CCM) with regard to the immunohistochemical expressions of matrix metalloproteinases (MMP) and selected extracellular matrix (ECM) proteins, which have a role in the regulation of angiogenesis. Fresh-frozen surgical specimens from patients with cAVM (n=14) and CCM (n=15) were immunohistochemically stained with antibodies for MMP-2, MMP-9, laminin, fibronectin and tenascin. To compare cAVM and CCM, expression of each protein was graded using a four-point scoring system for each histological layer of the lesion. MMP-2 and MMP-9 were more strongly expressed in the vascular walls of CCMs compared to cAVMs for all comparable layers: endothelium, subendothelium and the perivascular space. The stronger expression of MMP and other EMP associated with early angiogenesis in CCMs compared to AVMs may support the hypothesis that CCMs occur at earlier embryogenic stages than AVMs.
Neurosurgery | 2010
Sun Hi; Emel Akgun; Atilla Bicer; Abdulkadir Ozkan; Suheyla Uyar Bozkurt; Ozlem Kurtkaya; Demet Koc; M. N. Pamir; Turker Kilic
BACKGROUNDThe primary treatment for craniopharyngiomas is total excision, but recurrence is common. However, current knowledge on the mechanisms of recurrence is limited. OBJECTIVEWe hypothesized that recurrence is linked to the angiogenesis of the tumor. Recurrent and nonrecurrent tumor samples were compared with regard to expression of angiogenesis-related factors and angiogenic capacity in a corneal angiogenesis model. METHODSSpecimens of 4 recurrent and 6 nonrecurrent tumors were selected from 57 patients with adamantinomatous craniopharyngiomas. Sections were immunohistochemically stained with antibodies for vascular endothelial growth factor (VEGF), fibronectin, fibroblast growth factor (FGF)-2, platelet-derived growth factor (PDGF)-A, PDGF-B, platelet-derived growth factor receptor (PDGFR)-α, and PDGFR-β. Expression levels were graded using a 4-point scoring system and were compared. For corneal angiogenesis assay, tissue samples were inoculated in a micropocket created on the rat eye, and microvessels were counted on days 3, 5, 7, and 9 to evaluate angiogenic potential. RESULTSExpression of PDGFR-α and FGF-2 were significantly higher for recurrent tumors (P = .02 and P = .01). However, recurrent and nonrecurrent tumors did not differ in the expressions of other ligands and receptors (PDGF-A, PDGF-B, and PDGFR-β). Recurrent tumors displayed a higher angiogenic potential starting from the fifth day of corneal angiogenesis assay. CONCLUSIONThese findings suggest a relationship between recurrence of craniopharyngiomas and angiogenesis. New treatment modalities with selective PDGFR-α blockers may represent a novel and effective therapeutic option for the treatment of craniopharyngiomas.
Korean Journal of Spine | 2014
Yasar Bayri; Murat Sakir Eksi; Ramazan dogrul; Demet Koc; Deniz Konya
Spinal stabilization with fusion is the widely used method for traumatic or pathologic fracture of spine, spinal stenosis, and spondylolisthesis. Complications may emerge during or after the operations. Infection, hematoma and neurological deficits are early noticed findings. Screw and/or rod fractures present in long-term after surgery. Rod migration in out of the spinal column is a rare entity. A 67-year-old woman was visited our clinic for right leg pain. She had a previous spinal instrumentation surgery for spondylolisthesis in another center 6 years before. After radiological work-up, a distally migrated rod piece was observed in the retroperitoneal portion. The patient was operated for degenerative change; old instruments were replaced and extended to the L2 level with posterior spinal fusion. After the operation, her right leg pain improved. The asymptomatic migrated rod piece has regularly been followed clinically and radiologically, since then. Although it has rarely been reported, migration of the instrumentation material should be kept in mind. Spinal fixation without fusion makes the mechanical system vulnerable to motion effects of spine, especially in a degenerative and osteoporotic background. Long-term, even life-long follow-up is necessary for late term complications.
Pediatric Anesthesia | 2008
Arzu Gercek; Demet Koc; Bülent Erol; Binnaz Ay; Murat Bezer; Fevzi Yılmaz Göğüş
reported in a case with PDA 30 h after the procedure (4). The migrated devices are usually removed surgically, whereas in the presented case the device was removed by endovascular techniques. Two patients had late complications: peripheral embolization in the left leg 1 year after implantation of an Amplatzer device and sudden death 1.5 year later (2). In such procedures, regardless of the occluder type, the migration of device can happen in 1.1% of the cases and surgical removal is required in 0.2% of all the cases (3). Early and easy migration of the device can be caused by the technical reasons like inappropriate choice of the device (insufficient length of the rim). Device-defect ratio also had a significant effect on delivery success and composite success. Defect stretch diameter had the largest influence on outcome, and implantation was possible in only 67% if the stretched diameter of the defect was >20 mm (5). The other possible causes of migration of the device are either because of choice of the occluder or less experience in application of the device. The migration of the device in percutaneous transcatheter occlusion procedures may cause life-threatening complications and we suggest that all patients should go to intensive care unit postoperatively. The anesthesiologists should be careful to the developing techniques and complications of such procedures. Yusuf Unal M D* Serdar Kula M D† Gokcen Emmez M D* Rana Olgunturk M D† Sahin Yardim M D* *Department of Anesthesiology and Reanimation and †Department of Pediatric Cardiology, Gazi University School of Medicine, Ankara, Turkey (email: [email protected], [email protected]) References
Neurology India | 2015
Yasar Bayri; Bahattin Tanrikulu; Fatih Bayrakli; Demet Koc; Adnan Dagcinar
Sir, Yawning is a stereotyped event seen in all vertebrates. Neural networks in the brainstem, autonomic nervous system, hypothalamus, and limbic system may be involved in the physiology of yawning. Tumor-related yawning has rarely been reported.[1,2] We present a rare case of a patient with a meningioma at foramen magnum who presented with intractable yawning. After total removal of the tumor, the recurrent yawning resolved completely. Letters to Editor
Hepato-gastroenterology | 2003
Rasim Gencosmanoglu; Demet Koc; Nurdan Tozun