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Öğe CNS involvement of Langerhans cell histiocytosis. Report of 23 surgically treated cases(Walter De Gruyter & Co, 1996) Belen, D; Colak, A; Ozcan, OEWe present 23 cases of Langerhans cell histiocytosis with central nervous system (CNS) involvement. The major complaints were a mass on the cranial vault in fifteen (65 %), visual disturbance in four (16 %), polyurea-polydipsia in three (13 %), and progressive weakness in all extremities in one patient (4 %). Neurological examination revealed no abnormality in sixteen patients (70 %), cranial nerve palsy, visual field defect and optic atrophy in six (26 %) and paraparesis in one (4 %). Tumoral mass was found to be located on the cranial vault (65 %), in the suprasellar region (21 %) and in the spinal column (8 %). The cranium and spinal column were both involved in one patient. All patients underwent surgery. craniectomy with grossly total tumor excision plus cranioplasty (65 %), craniotomy with subtotal tumor excision (26 %), and vertebrectomy with grafting (13 %) were performed. The clinical, radiological and histopathological features, as well as therapeutical considerations are discussed and the pertinent literature is reviewed.Öğe Effect of CO2 laser on spinal epidural fibrosis(Springer-Verlag Wien, 1996) Colak, A; Bavbek, M; Aydin, NE; Renda, N; Acikgoz, BIn this study the effect of CO2 laser on spinal epidural fibrosis was examined in 24 guinea pigs which were divided into two groups. The first group was the control group, the second one the CO2 laser group. All animals had laminectomies at 3 levels. Re-exploration was performed three months after the laminectomy. In the second group the same procedure was performed but at the end of the re-exploration, CO2 laser irradiation of the epidural fibrotic tissue was done. The wounds in both groups were closed again. Four months later all animals were sacrificed. for verification and quantification of scar formation (postoperative fibrosis) light microscopic examinations and determination of hydroxyproline were done, using Bergman's spectrophotometric method. The differences which were observed between the two groups were statistically significant (U:134, p < 0.05). This study demonstrates the reducing effect of CO2 laser irradiation on epidural scar formation. The findings encourage its use as an alternative method of prevention of epidural fibrosis after spinal surgery.Öğe Endodermal sinus tumor and spinal cord compression(Amer Assoc Neurological Surgeons, 1997) Colak, A; Tekiner, A; Kocak, A[Abstract Not Available]Öğe A huge cerebral hydatid cyst associated with small liver cyst: A comparison of growth rates and sizes(Walter De Gruyter & Co, 1996) Vatansever, M; Biliciler, B; Aladag, MA; Colak, AThere are still some unknown aspects of the natural course of echinococcus infestation, especially in the brain. The growth rate of the cysts in brain and in other tissues is matter of some discussion. In this report, a huge primary cerebral hydatid cyst associated with a small liver cyst is presented and a possible relationship between the growth rates and the sizes of the two cysts is discussed. It is shown that the brain hydatid cyst grew faster than liver hydatid cyst by a ratio of 3:1.Öğe A new model for tethered cord syndrome: A biochemical, electrophysiological, and electron microscopic study(Karger, 1997) Kocak, A; Kilic, A; Nurlu, G; Konan, A; Kilinc, K; Cirak, B; Colak, AIn order to investigate the pathophysiology of the tethered cord syndrome, a few experimental models have been developed and used previously. In this study, the authors present a new experimental model to investigate the biochemical, electrophysiological, and histopathological changes in the tethered spinal cord syndrome. A model was produced in guinea pigs using an application of cyanoacrylate to fixate the filum terminale and the surrounding tissue to the dorsal aspect of the sacrum following 5-gram stretching of the spinal cord. The experiments were performed on 40 animals divided into two groups. The responses to tethering were evaluated with hypoxanthine and lipid peroxidation, somatosensory and motor evoked potentials, and transmission electron microscope examination. The hypoxanthine and lipid peroxidation levels significantly increased, indicating an ischemic injury (p < 0.01). The average hypoxanthine level in the control group was 478.8 +/- 68.8 nmol/g wet tissue, while ii, was 651.2 +/- 71.5 nmol/g in the tethered cord group, The lipid peroxidation level in group I Nas 64.0 +/- 5.7 nmol/g wet tissue, whereas it Nas 84.0 +/- 4.7 nmol/g in group II. In the tethered cord group, the latencies of the somatosensory and motor evoked potentials significantly increased, and the amplitudes decreased. These changes indicated a defective conduction in the motor and sensorial nerve fibers. In the transmission electron microscopic examinations, besides the reversible changes like edema and destruction in the gray-white matter junction, irreversible changes like scarcity of neurofilaments and destruction in axons and damage in myelin sheaths were observed. We consider that this work can be used as an experimental model for tethered cord syndrome.Öğe Protective effect of melatonin on experimental spinal cord ischemia(Springernature, 2003) Erten, SF; Kocak, A; Ozdemir, I; Aydemir, S; Colak, A; Reeder, BSStudy design: Experimental animal model to assess ischemic spinal cord injury following occlusion of the thoraco-abdominal aorta. Objectives: To measure whether melatonin administered to rabbits before and after occlusion exerts an effect on the repair of ischemia-reperfusion (IR) injury. Setting: Medical Biology Laboratory, Inonu University, Malatya, Turkey. Methods: Rabbits were divided into three IR treatment groups and one sham-operated (ShOp) control group. The three treatment groups had their infrarenal aorta temporarily occluded for 25 min, while the ShOp group had laparotomy without aortic occlusion. Melatonin was administered either 10 min before aortic occlusion or 10 min after the clamp was removed. Physiologic saline was administered to the control animals. After treatment, the animals were euthanized and lumbosacral spinal cord tissue was removed for the determination of relevant enzyme activities. Results: Malondialdehyde levels, indicating the extent of lipid peroxidation, were found to be significantly increased in the nonmelatonin treated (IR) group when compared to the ShOp group. Melatonin, whether given to pre- or post occlusion groups, suppressed malondialdehyde levels below that of the ShOp group. Catalase (CAT) and glutathione peroxidase (GSH-Px) enzyme activities were increased in the IR group compared to the ShOp group. Melatonin given preocclusion resulted in a significant decrease in both CAT and GSH-Px enzyme levels. The superoxide dismutase ( SOD) enzyme activity was decreased in the ischemia-reperfusion treatment group. However, the melatonin treatment increased SOD enzyme activity to levels approximating that of the ShOp group. Conclusion: To our knowledge, this is the first study that shows the effects of melatonin administered both pre- and postischemia on induced oxidative damage to injured spinal cords. Our data also expands on reports that melatonin administration may significantly reduce the incidence of spinal cord injury following temporary aortic occlusion.Öğe Unusual frontal osteoma, mimicking a haemangioma(Springer Verlag, 1996) Sarac, K; Biliciler, B; Vatansever, M; Aladag, MA; Colak, AWe report a patient with a frontal bone osteoma showing the classical findings of haemangioma. A craniectomy and total tumour excision was carried out.Öğe Unusual presentation of a sinonasal carcinoma mimicking an aneurysm rupture(Springer Verlag, 1998) Kocak, A; Erten, SF; Mizrak, B; Akbasak, A; Colak, AAlthough the association of subarachnoid hemorrhage (SAH) and tumoral lesions in adult is well known, hemorrhage from a sinonasal carcinoma extending to the intracranial cavity is exceedingly rare. In this paper, the authors report on a 12-year-old girl who presented with SAH caused by a sinonasal carcinoma located in the anterior skull base area. To our knowledge, this is the first report of a sinonasal carcinoma concomitant with SAH.Öğe An unusual presentation of metastatic adenocarcinoma in the cerebellum associated with intratumoral hemorrhage mimicking a stroke. A Case report(Walter De Gruyter & Co, 1998) Erten, SF; Ertas, E; Duygulu, C; Aydin, EN; Colak, ASpontaneous bleeding from a metastatic tumor in the brain is usually associated with melanoma, choriocarcinoma, or hypernephroma. We report a patient with rectum adenocarcinoma which metastasized into the cerebellum and mimicked a stroke, and discuss the clinical features and diagnostic problems of this uncommon condition.
