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SEYİTHANOĞLU, MEHMET HAKAN

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MEHMET HAKAN
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SEYİTHANOĞLU
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    PublicationOpen Access
    A Rare Cause of Headache in the Emergency Department: Intraventricular Epidermoid Cyst Rupture With Hydrocephalus.
    (2016-07-01) YIGIT, M; Seyithanoglu, MEHMET HAKAN; DUNDAR, TOLGA TURAN; SOGUT, O; YIGIT, E; SEYİTHANOĞLU, MEHMET HAKAN; DÜNDAR, TOLGA TURAN
    Lateral intraventricular tumors are not frequently observed. Since these tumors grow linearly rather than exponentially, they grow gradually and thus do not cause mass effects and hydrocephalus. This study is the case report of a rare great volume left intraventricular epidermoid cyst rupture. The tumor was found to be associated with mass effect on neighboring structures and hydrocephalus.
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    PublicationOpen Access
    Investigation of Brain Impairment Using Diffusion-Weighted and Diffusion Tensor Magnetic Resonance Imaging in Experienced Healthy Divers.
    (2018-11-17) SEYITHANOĞLU, MEHMET HAKAN; ABDALLAH, ANAS ABDELRAHIM SA; Dündar, TOLGA TURAN; KITIŞ, SERKAN; ARALAŞMAK, AYŞE; Gündağ, Papaker; SASANI, H; SEYİTHANOĞLU, MEHMET HAKAN; ABDALLAH, ANAS ABDELRAHıM SA; DÜNDAR, TOLGA TURAN; KİTİŞ, SERKAN; ARALAŞMAK, AYŞE; GUNDAG, MELİHA
    Background: The aim of this study was to understand the changes of decompression illness in healthy divers by comparing diffusion-weighted (DWI) and diffusion tensor MRI findings among healthy professional divers and healthy non-divers with no history of diving. Material/Methods: A total of 26 people were recruited in this prospective study: 11 experienced divers with no history of neurological decompression disease (cohort) and 15 healthy non-divers (control). In all study subjects, we evaluated apparent diffusion coefficient (ADC) and type of diffusion tensor metric fractional anisotropy (FA) values of different brain locations (e.g., frontal and parieto-occipital white matter, hippocampus, globus pallidus, putamen, internal capsule, thalamus, cerebral peduncle, pons, cerebellum, and corpus callosum). Results: ADC values of hippocampus were high in divers but low in the control group; FA values of globus pallidus and putamen were lower in divers compared to the control group. DWI depicted possible changes due to hypoxia in different regions of the brain. Statistically significant differences in ADC values were found in hypoxia, particularly in the hippocampus (p=0.0002), while FA values in the globus pallidus and putamen were statistically significant (p=0.015 and p=0.031, respectively). We detected forgetfulness in 6 divers and deterioration in fine-motor skills in 2 divers (p=0.002 and p=0.17, respectively). All of them were examined using neuro-psychometric tests. Conclusions: Repeated hyperbaric exposure increases the risk of white matter damage in experienced healthy divers without neurological decompression illness. The hippocampus, globus pallidus, and putamen are the brain areas responsible for memory, learning, navigation, and fine-motor skills and are sensitive to repeated hyperbaric exposure
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    PublicationOpen Access
    Diffuse Idiopathic Skeletal Hyperostosis Interfering with Ankylosing Spondylitis: A Case Report
    (2014-03-01T00:00:00Z) Taspinar, Ozgur; Aydin, Teoman; Kepekci, Muge; Peru, Celaleddin; Seyithanoglu, Hakan; AYDIN, TEOMAN; SEYİTHANOĞLU, MEHMET HAKAN
    Ankylosing spondylitis is the axial skeleton and sacroiliac crick, starting in late adolescence or early adulthood age, and is characterized by spondyloarthropathy. Some symptoms are confused with diffuse idiopathic skeletal hyperostosis. Our case had neck, back, waist, and heel pain and morning stiffness lasting about half an hour and was admitted with complaints. Lateral lumbar spine radiographs taken at the corners of the lumbar vertebral bodies compatible with DISH consecutive osteophytes were detected, and radiography of the calcaneus of the lateral foot showed hyperostosis compatible with DISH. However, the patient was diagnosed with ankylosing spondylitis because of a bilateral crick in the sacroiliac radiography. In this case-a differential diagnosis between DISH and ankylosing spondylitis-clinical and radiological features were assessed by reviewing the literature.
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    PublicationOpen Access
    Evaluation of Brainstem Subcortical Auditory Pathways with Diffusion Tensor Imaging After Gamma Knife Radiosurgery in Intracanalicular Vestibular Schwannoma
    (2021-01-01T00:00:00Z) Cesme, Dilek Hacer; Alkan, Alpay; Gultekin, Mehmet Ali; Sari, Lutfullah; Alkan, Gokberk; Seyithanoglu, Mehmet Hakan; Hatiboglu, Mustafa Aziz; ÇEŞME, DİLEK HACER; ALKAN, ALPAY; SEYİTHANOĞLU, MEHMET HAKAN; HATİBOĞLU, MUSTAFA AZİZ
    Objective: To investigate changes in DTI (Diffusion Tensor Imaging) parameters in brainstem subcortical auditory pathways after Gamma Knife Radiosurgery (GKR) in patients with intracanalicular vestibular schwannoma (ICVS) and to analyze the relationship between tumor volume and ADC (apparent diffusion coefficient) and FA (fractional anisotropy) values. Method: Seventeen patients with ICVS were evaluated before and after GKR. ADC and FA values of the lateral lemniscus (LL) and inferior colliculus (IC) and tumor volume were calculated. Patients who responded to GKR were classified as Group 1 and those who did not respond adequately as Group 2. The relationship between ADC and FA values and changes in tumor volume were analyzed. Results: Tumor volume significantly decreased after GKR. ADC values obtained from the tumor increased after GKR (p:0.002). There was no significant difference in LL and IC before and after GKR in terms of FA and ADC values (n:17). There was a positive correlation between response to treatment and contralateral LL ADC values after GKR (p=0.005, r:0.652). There was a negative correlation between contralateral IC FA values after GKR and response to treatment (p=0.017, r: -0.568). There was a significant difference between Groups 1 and 2 in regards to contralateral LL ADC (p=0.03) and IC FA values (p=0.017). Conclusion: Since the cochlear nerve and subcortical auditory pathways have low regeneration potential after nerve damage, ADC and FA changes in LL and IC may be explained with the presence of intracanalicular tumors prior to GKR. Since GKR does not cause additional damage to the subcortical auditory pathways at the brainstem level, we think that GKR is a noninvasive treatment method that can be used safely in patients with ICVS.
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    PublicationOpen Access
    Importance of Pre-treatment Fractional Anisotropy Value in Predicting Volumetric Response in Patients with Meningioma Treated with Gamma Knife Radiosurgery.
    (2021-01-28T00:00:00Z) Cesme, Dilek Hacer; Alkan, Alpay; Sari, Lutfullah; Yabul, Fatma; Temur, Hafize Otcu; Aykan, Mahmut Esat; Hatiboglu, Mustafa Aziz; Seyithanoglu, Mehmet Hakan; ÇEŞME, DİLEK HACER; ALKAN, ALPAY; SEYİTHANOĞLU, MEHMET HAKAN; HATİBOĞLU, MUSTAFA AZİZ
    Background: The importance of pre-treatment Diffusion Tensor Imaging (DTI) parameters in determining the response to treatment after radiosurgery in patients with meningioma has not yet been clearly revealed. Objective: This study was conducted to determine tumor volume changes in terms of radiological response in patients with meningioma treated with Gamma Knife Radiosurgery (GKR) and to analyze the relationship between Total Tumor Volume (TTV) and Diffusion Tensor Imaging (DTI) parameters. In addition, we investigated whether the response to treatment can be predicted by pre-radiosurgery DTI findings. Methods: Fifty-four patients were assessed using MRI and DTI before and after GKR. Mean Diffusivity (MD), Fractional Anisotropy (FA), Radial Diffusivity (RD), and TTV of tumour were determined. Patients with 10% or more decrease in TTV after GKR were classified as group 1 and those with less than 10% decrease in volume or increase in volume were considered group 2. The relationships between MD, RD, and FA values and TTV were investigated. Results: A decrease of 46.34% in TTV was detected in group 1 after GKR, while TTV increased by 42.91% in group 2. The lowest pre-treatment FA value was detected in group 1. In addition, after GKR, FA values showed a significant increase in group 1. MD and RD values increased in both groups after radiosurgery. There was a negative correlation between pre-treatment FA, RD, and MD values after radiosurgery. Conclusion: Detection of low FA values due to the poor fiber content in meningioma before radiosurgery may be a guide in predicting the response to treatment. Further studies are required to have a better understanding of the relationship between pre- and post-treatment follow-up FA values and tumor volume in determining the efficacy of GKR in patients with meningioma.
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    PublicationOpen Access
    Frameless Neuronavigation Assisted Brain Biopsy: Safety, Efficiency and Our Experience
    (2019-03-01T00:00:00Z) SEYİTHANOĞLU, MEHMET HAKAN; ÖZEK, ERDİNÇ; SEYİTHANOĞLU, MEHMET HAKAN; KİTİŞ, SERKAN; DÜNDAR, TOLGA TURAN; TEKİN, ABDURRAHIM; HATİBOĞLU, MUSTAFA AZİZ
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    PublicationOpen Access
    Comparison of the biochemical and radiological criteria for lumbar disc degeneration
    (2018-09-01) Seyithanoglu, MEHMET HAKAN; Kitis, SERKAN; Ozer, Omer Faruk; Kocyigit, ABDÜRRAHİM; DÜNDAR, Tolga; Papaker, Meliha Gundeg; SEYİTHANOĞLU, MEHMET HAKAN; KİTİŞ, SERKAN; ÖZER, ÖMER FARUK; KOÇYİĞİT, ABDÜRRAHİM
    Background: The relationship between radiological degeneration criteria on lumbar magnetic resonance imaging (MRI) and both the keratan sulfate (KS) and chondroitin sulfate (ChS) levels was examined in disc material taken from patients undergoing lumbar disc herniation (LDH) surgery. To examine whether the biochemical and radiological degeneration criteria testing the reliability of radiological degeneration findings agreed and to evaluate the contribution of the KS/ChS ratio to disc form (protruding or extruding).
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    PublicationOpen Access
    Glioblastoma Stem Cells and Comparison of Isolation Methods.
    (2019-06-01) Kaynar, MY; Dundar, TOLGA TURAN; Hatiboglu, MA; Ergul, Z; Sozen, E; Seyithanoglu, MH; Tuzgen, S; Karaoz, E; DÜNDAR, TOLGA TURAN; HATİBOĞLU, MUSTAFA AZİZ; SEYİTHANOĞLU, MEHMET HAKAN
    Background: Glioblastoma (GBM) is the most aggressive and the most common primary brain tumor. Over the last few years, studies have identified many genetical and phenotypical molecular situations for developing new treatment modalities in patients with GBM. Nevertheless, main problem for the GBM is radio-chemotherapy resistance and relapse after the surgery. The identification of glioma stem cells and microenvironmental influences has created a paradigm shift in targets of therapy. Current studies have shown that glioma stem cell is responsible for aggressiveness, recurrence and resistance to therapy of GBM. GBM stem cell isolated from human GBM multiforme fresh tissue samples is important both for curative therapeutic options and personalized targeted therapy. The purpose of this study was to determine the most suitable isolation method of GBM stem cells (GSCs). Methods: Tumor tissue sample was obtained during the surgical resection of lesion in patients with the diagnosis of GBM. Tumor stem cell isolation from tissue was performed in three different ways: 1) GBM cell isolation with trypsin; 2) GBM cell isolation with brain tumor dissociation Kit (BTD Kit); and 3) GBM cell isolation with tumor dissociation enzyme (TDE). Results: We showed that GSCs were isolated from tumor specimen using flow cytometry and immunofluorescence staining. Our study showed that isolation with BTD Kit is the most suitable method to isolate GBM tissue-derived glial tumor stem cells. Conclusions: The development of alternative personalized therapies targeting brain tumor stem cell is urgently needed. It is important to understand the fundamental mechanisms of driving stem cells. If their life cycle mechanisms can be identified, we can control the growth of GBM.
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    PublicationOpen Access
    Spontaneous Resolution of Paraparesis Because of Acute Spontaneous Thoracolumbar Epidural Hematoma
    (2012-01-01) GUNDAG, MELİHA; DOGAN, K.; Kitis, SERKAN; Ozkan, N.; GUNDAG, MELİHA; SEYİTHANOĞLU, MEHMET HAKAN; KİTİŞ, SERKAN
    Symptomatic spontaneous spinal epidural hematoma(SSEH) is an uncommon cause of cord compression that commonly is considered an indication for emergent surgical decompression. We aimed to investigate a patient with a SSEH that completely resolved clinically and radiographically, without surgical treatment. The patient presented three days after the sudden onset of back pain, numbness, and weakness. Magnetic Resonance Imaging (MRI) revealed a posterior thoracolumbar epidural hematoma extending from the level of T10 to L2 with significant cord compression. Decompression was recommended but he refused surgery and was managed conservatively. One month later weakness totally recovered and hematoma was absent on MRI.
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    PublicationOpen Access
    Investigation of cytotoxic, genotoxic, and apoptotic effects of curcumin on glioma cells
    (2019-03-01) SEYİTHANOĞLU, MEHMET HAKAN; ABDALLAH, ANAS; kitiş, serkan; GÜLER, ERAY METİN; DÜNDAR, TOLGA; GÜNDAĞ PAPAKER, MELİHA; SEYİTHANOĞLU, MEHMET HAKAN; KİTİŞ, SERKAN; GÜLER, ERAY METİN; KOÇYİĞİT, ABDÜRRAHİM; DÜNDAR, TOLGA TURAN; GUNDAG, MELİHA