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Dive into the research topics where Ozlem Ozen is active.

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Featured researches published by Ozlem Ozen.


Neurosurgery | 2005

Remote cerebellar hemorrhage after a spinal surgery complicated by dural tear: case report and literature review.

Oguz Karaeminogullari; Basar Atalay; Orcun Sahin; Metin Ozalay; Huseyin Demirors; Cengiz Tuncay; Ozlem Ozen; Reha N. Tandogan

OBJECTIVE AND IMPORTANCE: This report presents a case in which cerebellar hemorrhage occurred after lumbar decompression surgery that was complicated by dural tear and prolonged cerebrospinal fluid leakage. Remote cerebellar hemorrhage after spinal surgery is extremely rare. Our objective is to describe this unusual complication, discuss the possible mechanisms of remote cerebellar hemorrhage, and review the literature. CLINICAL PRESENTATION: A 73-year-old woman underwent surgery for lumbar spinal stenosis. A dural tear occurred during decompression, and the patient developed remote cerebellar hemorrhage on postoperative Day 2. INTERVENTION: The cerebellar hemorrhage was treated surgically, and a biopsy of hemorrhagic brain parenchyma revealed an arteriovenous malformation. CONCLUSION: Although it is an extremely rare complication, remote cerebellar hemorrhage should be kept in mind as a possible complication of spinal surgery, especially in operations complicated by dural tears.


Cytopathology | 2009

Diagnostic pitfalls in the evaluation of fine needle aspiration cytology of the thyroid: correlation with histopathology in 260 cases

Aysegul Haberal; S. Toru; Ozlem Ozen; Z. Arat; Banu Bilezikçi

Objectives:  Fine needle aspiration cytology (FNAC) of the thyroid is a non‐invasive, cost‐effective screening procedure that is valuable for distinguishing neoplastic lesions from non‐neoplastic nodules. The aim of this study was to determine the diagnostic accuracy of FNACs performed at our institution by correlating FNAC results with histopathological diagnoses.


Neuropathology | 2004

Chordoid meningioma: Rare variant of meningioma

Ozlem Ozen; Aylin Sar; Basar Atalay; Nur Altinors; Beyhan Demirhan

Chordoid meningioma is a rare variant of meningioma that bears a striking histological resemblance to chordoma and has greater likelihood of recurrence. Although most meningiomas occur in the intracranial, orbital and intravertebral cavities, rare meningiomas have been reported in extracranial organs; thus, it is important to be able to distinguish them from other neoplasms that have similar histology but different biological behavior and therapies. A case of chordoid meningioma in a 48‐year‐old woman who did not have Castlemans syndrome is described in the present report. The patient presented with a mass in her left frontoparietal region, and had been suffering from headaches for many years. Magnetic resonance imaging of the brain demonstrated an expansive lytic lesion in the squamous portion of the left temporal bone. The lesion extended in both directions. Histological examination of the surgical specimen revealed a tumor composed of cords and nests of eosinophilic vacuolated cells embedded in a myxoid matrix. A typical meningiomatous pattern was observed focally, and positive staining of the tumor cells for vimentin and epithelial membrane antigen confirmed the diagnosis of chordoid meningioma.


Neurosurgery | 2006

Systemic administration of phosphodiesterase V inhibitor, sildenafil citrate, for attenuation of cerebral vasospasm after experimental subarachnoid hemorrhage.

Basar Atalay; Hakan Caner; Melih Cekinmez; Ozlem Ozen; Bülent Celasun; Nur Altinors

OBJECTIVEOne of the phosphodiesterase isoenzymes, Type V (PDE V), specifically hydrolyzes cyclic guanosine monophosphate to cause vasoconstriction. This study analyses the effect of PDE V inhibition with sildenafil citrate (SC) on cerebral vasospasm and its effect on apoptotic changes of the vascular endothelium. METHODSTwenty-four rabbits were divided into four groups. The first group was composed of sham-surgery animals. The second group was the subarachnoid hemorrhage (SAH) group, in which cerebral vasospasm was induced. In the third group, sham-surgery rabbits were treated with SC. In the fourth group, animals were treated with SC after SAH. SC was administered for 48 hours, 0.7 mg/kg, three times per day in Groups 3 and 4. Basilar artery lumen circumferences were measured in all groups by computerized image analysis. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) method was used to evaluate the rate of apoptosis between SAH and SC-treated SAH groups. Results were compared by analysis of variance and paired t tests, and P values less than 0.05 were considered significant. RESULTSBasilar artery circumferences between groups were significantly different(P < 0.001). SC (0.7 mg/kg, three times per d) significantly dilated the basilar arteries in both the sham-surgery group (2370 ± 233 μm; P = 0.039) and the SAH group(2142 ± 195 μm; P = 0.006) after 48 hours of treatment. The TUNEL method for apoptosis revealed that actual numbers of the apoptotic endothelial cells per cross section after SAH in the control (no treatment) (73 ± 2) and SC-treated (0.7 mg/kg) groups(76 ± 3) were not significantly different (P > 0.05). CONCLUSIONThe vasodilatory effect of SC was observed to be significant on normal cerebral vessels and after SAH-induced vasospasm. SC did not prevent apoptosis of the endothelium in our study, which suggests that prevention of apoptosis is not necessary in the treatment of cerebral vasospasm.


Spine | 2013

Minocycline treatment inhibits lipid peroxidation, preserves spinal cord ultrastructure, and improves functional outcome after traumatic spinal cord injury in the rat.

Erkin Sonmez; Serdar Kabatas; Ozlem Ozen; Gulten Karabay; Suna Turkoglu; Ersin Ogus; Cem Yilmaz; Hakan Caner; Nur Altinors

Study design. A prospective, randomized experimental research. Objective. To evaluate the short- and long-term neuroprotective effects of minocycline on the secondary injury process of an experimental traumatic spinal cord injury (SCI) model. Summary of Background Data. Traumatic SCI is a devastating problem of health that results in high morbidity and mortality rates. The loss of function after SCI results from both the primary mechanical insult and the subsequent, multifaceted secondary response. Methods. A total of 80 adult male Spraque-Dawley rats (breeded by the Baskent University Animal Research Center) were randomly divided into 4 groups. A T10 contusion injury was produced by using modified Allen technique in all groups except the control group. No medication was administered to the rats in the trauma group. Minocycline was administered intraperitoneally and intravenously to the treatment groups. Short-term and/or long-term neuroprotective effects of minocycline on the lipid peroxidation (malondialdehyde, glutathione), apoptosis (terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate-biotin nick end labeling), ultrastructure of spinal cord (tissue electron microscopy), and behavioral assessments (Basso-Beattie-Bresnahan) were evaluated. Results. As compared with the trauma group, tissue malondialdehyde and glutathione levels demonstrated that minocycline significantly diminishes lipid peroxidation. Electromicroscopic study showed that minocycline preserves the ultrastructure of spinal cord tissue in the early post-traumatic period. Minocycline treatment significantly reduced the number of terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate-biotin nick end labeling positive cells both 1 day and 28 days after SCI. Behavioral assessments showed significant improvement in the hind limb functions of minocycline receiving rats starting 7 days after the SCI. Any statistically significant difference was not found between intraperitoneal or intravenous routes for minocycline injection. Conclusion. Minocycline is neuroprotective and contributes to functional improvement after traumatic SCI by eliminating the destructive process of secondary injury. Having both satisfying anti-inflammatory and antiapoptotic effects in experimental models, it promises to be of therapeutic use in human SCI.


Neurological Research | 2006

The effect of mexiletine on the level of lipid peroxidation and apoptosis of endothelium following experimental subarachnoid hemorrhage

Orhan Sen; Hakan Caner; M. Volkan Aydin; Ozlem Ozen; Basar Atalay; Nur Altinors; Murad Bavbek

Abstract Objective: The role of apoptosis in etiopathogenesis of vasospasm is not clearly understood yet. It is widely accepted that protection of the endothelial cells from the process of apoptosis could have beneficial effects on cerebral vasospasm after subarachnoid hemorrhage (SAH). Mexiletine blocks sodium and calcium channels and activates ATP-sensitive K+ channels. Moreover, mexiletine is known to have potent antioxidant effects through inhibiting free-radical production. Methods: Twenty-one rabbits were allocated into three groups randomly. Group I was sham operated group (n=7). SAH occurred but no medication was given to the Group II rabbits (SAH only group) (n=7). Mexiletine (50 mg/kg, b.i.d., i.p.) was administered just before SAH and continued until 48 hours following SAH to the Group III rabbits (Mexiletine treated group) (n=7). The ApopTag peroxidase in situ apoptosis detection kit (Serologicals Corporation, former Intergen) was used to demonstrate apoptosis in a cross section of basillary arteries. Thiobarbituric acid reactive material was used to determine the lipid peroxidation levels. Results: There was a statistically significant difference between lipid peroxidation product levels of the control and SAH only groups (p<0.05). The level of lipid peroxidation production in Mexiletine treated group was significantly lower compared with SAH only group (p<0.05) but not significantly higher than the control group (p>0.05). Discussion: In the present study we investigated the antioxidant action of mexiletine on apoptosis of endothelium following a rabbit SAH model. This experimental study directly suggested that lipid peroxidation is an important step in development of apoptosis in endothelial cells and prevention of structural integrity of endothelial cell should play a beneficial role in attenuation of cerebral vasospasm. Mexiletine treatment prevented the increase in lipid peroxidation and cerebral vasospasm. Examination of endothelial cells by staining specific for apoptosis demonstrated significant protection of cell integrity in the treated group.


Pathology Research and Practice | 2011

Intravenous lipoleiomyomatosis of uterus with cardiac extension: a case report.

Çiğdem Vural; Ozlem Ozen; Beyhan Demirhan

A case of intravenous leiomyomatosis (IVL) with histological features of a lipoleiomyoma (intravenous lipoleiomyoma) in a 48-year-old woman is reported. The patient, with the tumor located in the uterus and extended up on the right side of the heart through the inferior vena cava, was diagnosed as having a cardiac mass. She displayed symptoms of dyspnea, chest pain due to the cardiac mass, as well as pelvic pain and dysmenorrhea. She underwent cardiac surgery because of a right atrial mass, and the histopathological diagnosis was leiomyoma without the knowledge of a uterine mass. Afterwards, a right adnexial mass was detected in the pelvis, and a total hysterectomy-bilateral salpingo-oophorectomy was performed for the adnexial mass, which was also diagnosed as leiomyoma. In this case report, we describe an intravenous lipoleiomyomatosis of the uterus which, at the initial clinical presentation, showed cardiovascular symptoms. We emphasize the histopathological features and the differential diagnosis of this rare tumor in the light of the literature.


Journal of Clinical Neuroscience | 2009

Solitary fibrous tumor

Cem Yilmaz; Serdar Kabatas; Ozlem Ozen; Salih Gulsen; Hakan Caner; Nur Altinors

Intracranial solitary fibrous tumors (SFT) are typically dural based, CD34-positive neoplasms of mesenchymal origin. Since they were first described in 1996 at the meninges, fewer than 100 SFT had been reported in both cranial and spinal compartments of the central nervous system. SFT can resemble other spindle cell tumors both radiologically and histopathologically, and differentiation can be best achieved through viewing their ultrastructure and using immunohistochemical techniques. In this report, we present four patients with SFT. Upon diagnosing two patients with SFT located in the cerebellopontine angle and parasagittal areas, we reviewed our pathological files and found two more patients; one having a parasagittal tumor and the other having a convexity tumor, that had been diagnosed with hemangiopericytoma. These tumours proved to be SFT after an immunohistochemical re-examination.


Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2011

Clinical significance of TRAIL and TRAIL receptors in patients with head and neck cancer.

Burcak Yoldas; Cem Ozer; Ozlem Ozen; Tuba Canpolat; Isilay Dogan; Thomas S. Griffith; Salih Sanlioglu; Levent N. Ozluoglu

Tumor necrosis factor (TNF)‐related apoptosis‐inducing ligand (TRAIL) is a death ligand currently under clinical trials for cancer. The molecular profile of TRAIL and TRAIL receptors has not yet been mapped for patients with laryngeal squamous cell carcinoma (SCC) or patients with oral cavity squamous cell carcinoma (OCSCC).


Neurological Research | 2005

Effect of melatonin on cerebral vasospasm following experimental subarachnoid hemorrhage

M. Volkan Aydin; Hakan Caner; Orhan Sen; Ozlem Ozen; Basar Atalay; Melih Cekinmez; Nur Altinors

Abstract Object: The current study was undertaken to determine whether melatonin therapy reverses vasospasm and prevents apoptosis by inhibiting lipid peroxidation in an experimental subarachnoid hemorrhage (SAH) model. Materials and methods: The rabbits were divided into four groups as follows: Group 1, SAH + melatonin (5 mg/kg/i.p. BID) simultaneously with SAH (n = 6); Group 2, SAH + melatonin (5 mg/kg/i.p. BID) treated 2 hours after SAH (n = 6); Group 3, control group (n = 4); Group 4, SAH only (n = 6). Light microscopic examinations of the basilar arteries were performed to demonstrate the pathophysiological changes of the arterial wall with hematoxylin– eosin. Apoptosis: Immunohistology using the ApopTag Peroxidase In Situ Apoptosis Detection Kit was used to demonstrate apoptosis in a cross section of basilary arteries. Apoptotic index was calculated as the number of the immunoreactive nuclei per total number of endothelial cells, and expressed as a percentage. Results: The results of measurements of diameters of the vessels between groups were significantly different (p = 0.028). While basilar arteries of the SAH only group showed 57% constriction, Groups 1 and 2 were calculated as 33 and 26% constriction, respectively, compared with the control group (p < 0.05). And also Groups 1 and 2 showed significant protection of apoptosis compared with Group 4. The difference between the four groups was tested by Kruskal–Wallis test and the significance between the two groups was tested by Mann– Whitney U-test. Conclusion: Melatonin with its strong antioxidant effect can prevent SAH-induced vasospasm and apoptosis of endothelial cells of vessels.

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