Yavuz Aras
Istanbul University
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Featured researches published by Yavuz Aras.
World Neurosurgery | 2014
Altay Sencer; Ali Güven Yörükoğlu; Mehmet Osman Akcakaya; Yavuz Aras; Aydin Aydoseli; Osman Boyali; Fahir Sencan; Pulat Akin Sabanci; Cengiz Gomleksiz; Murat Imer; Talat Kırış; Kemal Hepgul; Omer Faruk Unal; Nail Izgi; Ali Canbolat
OBJECTIVE To evaluate the clinical outcomes of patients with lumbar disc disease undergoing fully endoscopic surgery at a single clinic. METHODS Between August 2009 and January 2012, 163 patients (74 men and 89 women) underwent fully endoscopic lumbar discectomy. All patients were followed for 1 year after surgery. The Oswestry Disability Index and a visual analog scale were used to analyze outcomes. RESULTS During the follow-up period, 114 (70%) patients had no complaints, 30 (18%) patients had occasional pain, and 19 (12%) patients had no improvement. During postoperative follow-up, 8 patients required repeat surgery for recurrence or residual fragments. Postoperatively, 4 patients experienced dysesthesia, which completely resolved in time. Neurologic deterioration occurred in 5 patients, 4 of whom recovered completely without any intervention. Dural tears occurred in 6 patients. CONCLUSIONS Fully endoscopic interlaminar or transforaminal surgeries are safe and effective treatment modalities for lumbar disc herniations. Despite the difficulties of acquiring this new technique, good results can be achieved with sufficient experience.
Cancer Cell International | 2011
Mine Erguven; Ayhan Bilir; Nuray Yazihan; Ezgi Ermis; Akin Sabanci; Esin Aktas; Yavuz Aras; Vehbi Alpman
BackgroundGlioblastoma (GBM) develops resistance to the advances in chemotherapy leading to poor prognosis and life quality. Consequently, new treatment modalities are needed. Our aims were to investigate the effects of combined noscapine (NOS) and imatinib mesylate (IM) on human GBM in vitro and the role of midkine (MK) in this new combination treatment.MethodsMonolayer and spheroid cultures of T98G human GBM cell line were used to evaluate the effects of IM (10 μM), Nos (10 μM) and their combination on cell proliferation and apoptotic indexes, cell cycle, the levels of antiapoptotic MK, MRP-1, p170, PFGFR-α, EGFR, bcl-2 proteins, apoptotic caspase-3 levels, morphology (SEM) and ultrastructure (TEM) for 72 hrs. Results were statistically analyzed using the Students t-test.ResultsThe combination group induced highest decrease in cell proliferation and apoptotic indexes, caspase-3 levels, MRP-1 and PDGFR-α levels. The decrease in p170 levels were lower than IM but higher that NOS. The highest increases were in EGFR, MK, bcl-2 and cAMP levels in the combination group. The G0+G1 cell cycle arrest at the end of 72nd hr was the lowest in the combination group. Apoptotic appearence was observed rarely both in the morphologic and ultrastructural evaluation of the combination group. In addition, autophagic vacuoles which were frequently observed in the IM group were observed rarely.ConclusionsThe combination of Nos with IM showed antagonist effect in T98G human GBM cells in vitro. This antagonist effect was correlated highly with MK levels. The effects of NOS on MRP-1, MK and receptor tyrosine kinase levels were firstly demonstrated in our report. In addition, we proposed that MK is one of the modulator in the switch of autophagy to cell death or survival/resistance.
Gene | 2013
Hulya Azakli; Candan Gürses; Muzaffer Arikan; Aydin Aydoseli; Yavuz Aras; Altay Sencer; Aysen Gokyigit; Bilge Bilgic; Duran Ustek
INTRODUCTION Hippocampal sclerosis is the most common lesion in patients with mesial temporal lobe epilepsy. Recently, there has been growing evidence on the involvement of mitochondria also in sporadic forms of epilepsy. In addition, it has been increasingly argued that mitochondrial dysfunction has an important role in epileptogenesis and seizure generation in temporal lobe epilepsy. Although mtDNA polymorphisms have been identified as potential risk factors for neurological diseases, the link between homoplasmy and heteroplasmy within tissues is not clear. We investigated whether mitochondrial DNA (mtDNA) polymorphisms are involved in a case report of a patient with mesial temporal lobe epilepsy-hippocampal sclerosis (MTLE-HS). DESIGN We report the whole genome mtDNA deep sequencing results and clinical features of a 36-year-old woman with MTLE-HS. We used pyrosequencing technology to sequence a whole mitochondrial genome isolated from six different regions of her brain and blood. To assess the possible role of mitochondrial DNA variations in affected tissues, we compared all specimens from different regions of the hippocampus and blood. RESULTS In total, 35 homoplasmic and 18 heteroplasmic variations have been detected in 6 different regions of the hippocampus and in blood samples. While the samples did not display any difference in homoplasmic variations, it has been shown that hippocampus regions contain more heteroplasmic variations than blood. The number of heteroplasmic variations was highest in the CA2 region of the brain and accumulated in ND2, ND4 and ND5 genes. Also, dentate and subiculum regions of the hippocampus had similar heteroplasmic variation profiles. DISCUSSION We present a new rare example of parallel mutation at 16223 position. Our case suggests that defects in mitochondrial function might be underlying the pathogenesis of seizures in temporal lobe epilepsy.
Journal of Neurosurgery | 2012
Yavuz Aras; Mehmet Osman Akcakaya; Seher N. Unal; Bilge Bilgic; Omer Faruk Unal
Imatinib mesylate has become the treatment of choice for gastrointestinal stromal tumors (GISTs) and has made a revolutionary impact on survival rates. Bone marrow necrosis is a very rare adverse event in malignant GIST. Bone metastases are also rarely encountered in the setting of this disease. The authors report on a patient with malignant GIST who developed a bone lesion, mimicking spinal metastasis on both MR imaging and FDG-PET/CT. Corpectomy and anterior fusion was performed, but the pathology report was consistent with bone marrow necrosis. Radiological and clinical similarities made the distinction between metastasis and bone marrow necrosis challenging for the treating physicians. Instead of radical surgical excision, more conservative methods such as percutaneous or endoscopic bone biopsies may be more useful for pathological confirmation, even though investigations such as MR imaging and FDG-PET/CT indicate metastatic disease.
Neurological Research | 2014
Pulat Akιn Sabancι; Mine Erguven; Nuray Yazihan; Esin Aktas; Yavuz Aras; Erdinç Civelek; Aydιn Aydoseli; Murat Imer; Mehmet Gürtekin; Ayhan Bilir
Abstract Objectives: The objectives of this study were to test the effects of the new combination treatment modality, sorafenib (SOR) and lithium chloride (LiCl) and to assess whether midkine (MK) protein has a role in any potential effects. Methods: Monolayer and spheroid cultures of T98G human glioblastoma multiforme (GBM) cells were treated with LiCl and SOR (inhibition concentration 50 value = 100 μM), or their combination, or were left untreated (control). Cell proliferation and apoptotic indices, the mechanism of action, and the levels of apoptotic and anti-apoptotic proteins were evaluated in monolayer cultures and ultrastructure was evaluated by transmission electron microscopy (TEM) in spheroid cultures after for 72 hours. Results: All drug applications decreased cell numbers and increased the apoptotic index. The combination shows a synergistic effect. In the combination group, the decrease in cell numbers and the increase in the apoptotic index were significantly greater than with the individual drugs (P < 0·01). The combination treatment led to the greatest decreases in MRP-1 and p170 levels; but the greatest decreases in p-STAT-3, p-ERK (P < 0·05), p-AKT, p-GSK-3-beta (P < 0·01), EGFR (P < 0·01), NF-kappa-β levels were with SOR alone, followed by the combination. The decreases in MK levels in the SOR and combination groups were similar (P = 0·06). Severe ultrastructural damage was more frequently observed in the combination group compared with the other groups. Conclusions: These results suggest the possibility that the addition of LiCl to SOR could improve the prognosis in at least some patients who need both cancer and psychotherapy and indicate the need for further studies.
Turkish journal of trauma & emergency surgery | 2013
Altay Sencer; Aydin Aydoseli; Yavuz Aras; Mehmet Osman Akcakaya; Cengiz Gomleksiz; Halil Can; Ali Canbolat
BACKGROUND We investigated the individual and combined effects of magnesium sulphate, which is an N-Methyl-D aspartate receptor antagonist (NMDA), and z-LEHD-FMK, which is a caspase 9 inhibitor, on the genesis of secondary injury in a rat spinal cord injury model. We aimed to minimize the effects of secondary injury in spinal cord trauma by choosing these two agents which served to block the two major mechanisms of cell loss, apoptosis and necrosis. METHODS The drugs were given to the subjects according to their groups, either in singular or combined fashion. For motor examination, the subjects were kept under close clinical evaluation for five days. Histopathological examination and the emerging spinal cord samples were prepared with haematoxylene-eosin and Tunel techniques. RESULTS A statistically significant difference in favor of the treatment groups has been found between the treatment and control groups in terms of histological data. However, there was no difference in the evaluation of motor examination between trauma and treatment groups. CONCLUSION We have found no difference between the individual and combined uses of MgSO4 and z-LEHD-FMK in the prevention of secondary injury; however, there were better histological results in the treatment groups compared to trauma and control groups which gives us hope for future investigations.
Journal of Neurosurgery | 2012
Altay Sencer; Yavuz Aras; Mehmet Osman Akcakaya; Burcu Göker; Talat Kırış; Ali Canbolat
OBJECT Traumatic posterior fossa epidural hematoma (PFEDH) is rare, but among children it may have a slightly higher incidence. With the widespread use of CT scanning, the diagnosis of PFEDH can be established more accurately, leading to an increased incidence of the lesion and possibly to a better patient prognosis. This study presents 40 pediatric cases with PFEDH. METHODS The authors assessed the type of trauma, clinical findings on admission, Glasgow Coma Scale scores, CT findings (thickness of the hematoma, bone fracture, compression of the fourth ventricle, and ventricle enlargement), type of treatment, clinical course, and prognosis. Early postoperative CT scans (within the first 6 hours) were obtained and reviewed in all surgical cases. RESULTS Twenty-nine patients underwent surgery and 11 patients received conservative therapy and close follow-up. All patients fared well, and there was no surgical mortality or morbidity. CONCLUSIONS Based on the data in this large series, the authors conclude that PFEDH in children can be treated in experienced centers with excellent outcome, and there is no need to avoid surgery when it is indicated.
Clinical Neurology and Neurosurgery | 2013
Yavuz Aras; Mehmet Osman Akcakaya; Aydin Aydoseli; Nail Izgi
Meningiomas are tumors arising from the arachnoid cap cells f the arachnoid villi in the meninges. Usually they have a dural ttachment [4]. However, meningiomas without dural attachment ave been previously described. Sylvian fissure is a rare location or this kind of meningiomas with only 25 reported cases to the est of our knowledge [1–5]. We present two additional cases of ylvian fissure meningiomas in two young male patients, which ere managed with staged surgery.
Journal of Neurosurgery | 2012
Pulat Akin Sabanci; Yavuz Aras; Aydin Aydoseli; Serra Sencer; Altay Sencer; Mine Erguven; Nail Izgi
Intracranial aneurysms are extremely rare in infancy. No consensus has yet been developed about the exact treatment of this rare situation. The authors report the case of a 47-day-old male infant who had multiple seizures on the same day, leading to the diagnosis of an intracranial aneurysm. The case was managed conservatively with close imaging follow-up, and the patient had a good recovery. The results of neurological examination were completely normal at the 5-year follow-up visit. These rare lesions may be suspected on the basis of clinical findings and correctly diagnosed with current neuroradiological imaging modalities. The authors believe this report contributes valuable imaging data on rare childhood aneurysms to the literature, as well as emphasizing the importance of clinical and imaging information in therapeutic decision making in children with intracranial vascular problems.
Turkish Neurosurgery | 2011
Mehmet Osman Akcakaya; Yavuz Aras; Ali Güven Yörükoğlu; Cem Ovalioglu; Altay Sencer
Intradural foreign bodies after penetrating injuries are seen very rarely. Limited number of cases of glass fragments in the spinal canal were reported previously. Migration of foreign bodies and delayed onset of neurological symptoms due to foreign bodies were also reported. In this report a 33-year-old male patient was presented, who had penetration of glass fragments through oropharyngeal mucosa in to the spinal canal after crashing into a glass door. Glass fragment, which migrated through an unusual route, and reached cervical spinal intradural space, caused neuropathic pain with radicular symptoms, 21 years after the initial injury. This case report emphasize that after penetrating injuries of spine, foreign bodies may remain silent until the patient became symptomatic years after the initial injury and these foreign bodies may migrate to extreme distant and unexpected locations in the central nervous system.