Gökhan Kurt

Intracranial Meningiomas of Childhood and Adolescence

Meningiomas are rare intracranial neoplasms in childhood and adolescence, representing 0.4–4.1% of the pediatric-age tumors and 1.5–1.8% of all intracranial meningiomas. The goal of this study was to determine epidemiology, clinical and radiological features, and long-term outcome of childhood and adolescence meningiomas. Patients operated for intracranial meningiomas of childhood and adolescence between 1983 and 2003 at Gazi University School of Medicine, Department of Neurosurgery, were evaluated retrospectively. This study presents 11 cases (6 male, 5 female), ranging in age from 14 months to 17 years. Age and sex distribution, presenting symptoms, neurological examination results, location of meningiomas, radiological and histopathological findings, and prognosis were reviewed. The results were compared with those reported in the existing literature. Atypical and malignant meningiomas seem to be more common in childhood and adolescence with respect to adult meningiomas. Tumor location, completeness of tumor removal, and pathological grade are the most important prognostic factors.

Neuroprotective effects of infliximab in experimental spinal cord injury

BACKGROUND The aim of the study is to assess the effects of infliximab, a TNF-alpha receptor blocker, in a spinal cord clip compression injury model. METHODS Clip compression injury model was used for producing spinal cord injury on 32 adult, male Wistar rats (Gazi University Animal Research Laboratory, Ankara, Turkey). After exposing the vertebral column between T7 and T10, total laminectomy was performed with the assistance of a high-speed drill and a surgical microscope. The dura was left intact. Spinal cord injury was performed on all rats with application of a 70-g closing force aneurysm clip for 1 minute. The rats were randomly allocated into 4 groups. Control group received no further therapy, whereas the other 3 groups received methylprednisolone (30 mg/kg intraperitoneal), infliximab (5 mg/kg subcutaneous), and a mixture of these 2 agents. All rats were killed 72 hours later, and the level of lipid peroxides in traumatized spinal cord tissue were measured as thiobarbituric acid-reactive material and determined using the method of Mihara and Uchiyama (Determination of malonaldehyde precursor in tissue by thiobarbituric acid test. Anal Biochem 1978;86(1):271-8). RESULTS Treatment with infliximab and methylprednisolone decreased MDA levels in rats with spinal cord injury with a statistically significant difference. In addition, combined therapy achieved a more profound decrease in tissue MDA levels, which was also statistically significant. CONCLUSIONS Infliximab is found as effective as methylprednisolone on spinal cord clip compression injury. Moreover, the combination of these 2 agents demonstrated higher efficacy suggesting a synergistic effect between these 2 agents. However, further studies regarding functional and behavioral analyses as well as biochemical markers are required.

ROLE OF ANTIFIBROTIC CYTOKINE INTERFERON-γ IN THE PREVENTION OF POSTLAMINECTOMY PERIDURAL FIBROSIS IN RATS. Commentary

OBJECTIVE Extensive peridural fibrosis after spinal surgery may be the underlying cause of failed-back syndrome in some cases. There is increasing evidence that generation of specific cytokine patterns by immune and structural cells and interactions among these cells mediate many of the key events involved in fibrogenesis. Interferon-gamma (IFN-gamma) has several potential antifibrotic actions, including inhibition of fibroblast proliferation and collagen deposition, promotion of fibroblast apoptosis, and inhibition of production and action of the fibrogenic cytokine, transforming growth factor-beta. We conducted a study to determine the effectiveness of IFN-gamma in preventing postlaminectomy peridural fibrosis in rats. To the best of our knowledge, this is the first study testing immunotherapy in peridural fibrosis. Type 2 cytokine hypothesis of fibrogenesis is emphasized. METHODS Laminectomies were performed in 30 rats. We administered 2000 U/d IFN-gamma, 20,000 U/d IFN-gamma, or 0.2 ml/d saline to the laminectomy site through a silicone catheter for 3 days in blinded fashion. The amount of scar tissue, fibroblast density, inflammatory cell density, arachnoidal involvement, and bone regeneration were analyzed histologically. RESULTS Histopathological examination showed a significantly reduced amount of scar tissue and fibroblast density in the low-dose IFN-gamma group compared with the control and high-dose IFN-gamma groups. A significant increase was detected in inflammatory cell density in the high-dose IFN-gamma group compared with the control and low-dose IFN-gamma groups. CONCLUSION Cytokines play a critical role in wound healing, tissue repair, and fibrogenesis. This study suggests that topical application of low-dose IFN-gamma is an effective and safe method of preventing peridural fibrosis, but further studies with different doses, durations, and intervals are required to achieve better results.

Neuroprotective effects of gabapentin on spinal cord ischemia-reperfusion injury in rabbits.

OBJECT Extensive research has been focused on neuroprotection after spinal cord trauma to alleviate the effects of secondary injury. This study aims to investigate the neuroprotective effects of gabapentin in an experimental spinal cord ischemia reperfusion injury. METHODS Thirty-two adult male New Zealand white rabbits received spinal cord ischemic injury using the aortic occlusion model. Animals were divided into 4 groups (sham, control, low-dose, and high-dose treatment groups; 8 rabbits in each group). High (200 mg/kg) and low (30 mg/kg) doses of gabapentin were administered to the animals in the treatment groups after spinal cord ischemic injury. Neurological status of the animals, ultrastructural findings in injured tissue samples, and levels of tissue injury markers in these 2 groups were compared with findings in the animals that did not receive the ischemic procedure (sham-operated group) and those that received normal saline after administration of ischemia. RESULTS Regarding levels of tissue injury marker levels after ischemic injury, animals in the gabapentin-treated groups demonstrated better results than animals in the other groups. The ultrastructural findings and caspase-3 activity were similar. The treatment groups demonstrated better results than the other groups. CONCLUSIONS Gabapentin demonstrated significant neuroprotection after early phases of ischemic injury. Further studies with different experimental settings including neurological outcome are required to achieve conclusive results.

Neuroprotective effects of infliximab in experimental spinal cord ischemic injury

Reactive oxygen species (ROS) have been implicated in the pathogenesis of spinal cord injury after both ischemia-reperfusion (I/R) and trauma. This experimental study was designed to investigate the potential effects of infliximab, an anti-tumor necrosis factor-α agent, on I/R injury of the rabbit spinal cord. Eighteen New Zealand white rabbits were divided into three groups, each consisting of six rabbits: sham (no I/R), I/R, and infliximab (I/R + infliximab). Spinal cord ischemia was induced by applying an infrarenal aortic cross clamp for 30 minutes. At 48 hours after ischemia, animals were functionally evaluated using the Tarlov score. Changes in the spinal cord were observed by measuring tissue levels of malondialdehyde (MDA), glutathione (GSH), advanced oxidation protein products (AOPP), and superoxide dismutase (SOD) and by evaluating hematoxylin-eosin-stained sections. At 48 hours after ischemia, the Tarlov scores in the infliximab group were higher than those of the I/R group, MDA and AOPP levels in the I/R group were significantly higher than those in the sham and infliximab groups (p < 0.05), and SOD levels in the infliximab group were significantly higher than those in the I/R and sham groups (p < 0.05). The sham group had higher GSH levels than the infliximab group; however, the difference was not statistically significant (p > 0.05). Histological examination revealed that the infliximab group had significantly less vascular proliferation, edema, and neuron loss than the I/R group. These results indicate that infliximab may protect the spinal cord against injury in a rabbit I/R model.

A comparison of the local effectiveness of mitomycin C, aprotinin, and Adcon-L in experimental peridural fibrosis

BACKGROUND Peridural fibrosis and leptomeningeal adhesion formation are among the common causes of FBSS. Various materials have been used to prevent the compressive effect of postoperative PF on neural structures. We investigated and compared the effects of 3 agents--aprotinin, mitomycin C, and Adcon-L--to PF after lumbar laminectomy in rabbits. METHODS Four groups each including 8 rabbits were formed: Adcon-L, aprotinin, mitomycin C, and control groups. L3 laminectomy was performed on each animal. One of the 3 agents was administered locally to laminectomy areas in each group. All the animals were killed 4 weeks after the surgery. Peridural fibrosis, arachnoidal fibrosis, and dural adhesions were evaluated histologically and graded. The results were compared statistically by using a standard chi2 test. RESULTS There were significant differences in the PF grades among the experimental groups and the control group (P < .05). When the fibroblast density and the inflammatory cell density were evaluated, the grades of the experimental groups were better compared with the grades of the control group, but the difference was not statistically significant (P > .05). CONCLUSION Various materials have been used to prevent the compressive effect of postoperative PF on the neural structures. Aprotinin, mitomycin C, and Adcon-L are effective in preventing PF and dural adhesions in postlaminectomy areas. However, mitomycin C and Adcon-L were more effective than aprotinin in preventing peridural scarring.

Comparison of Oxiplex and Gore-Tex effectivity in an experimental peridural fibrosis model

OBJECTIVE The authors conducted a study to compare the effectiveness of Oxiplex and Gore-tex in preventing postlaminectomy peridural fibrosis in rats. Peridural fibrosis is a common cause of pain in patients undergoing spinal surgery. To prevent scar formation numerous materials and methods have been employed such as non steroidal anti-inflammatory drugs (NSAIDs), Gelfoam, Oxiplex, Gore-tex, carboxymethil cellulose, Adcon-L, autogenous adipose grefting, mitomisin, and radiotherapy have been investigating for a long time, but only moderate success has been obtained. METHODS Laminectomies were performed at the fourth lumbar vertebra (L-4) in 30 rats. Oxiplex or Gore-Tex was applied over the dura mater with the aim to perform a blinded evaluation of their effects. In the control group, only a L-4 laminectomy was performed. Animals were sacrificed 28 days after the surgical procedure. The extent of peridural fibrosis was evaluated on spine specimens by histological analysis. RESULTS Both groups of animals treated with either Oxiplex or Gore-Tex showed a significant reduction in the degree of peridural fibrosis as compared to the control group. However no significant difference in the prevention of peridural fibrosis was observed between the Oxiplex and Gore-Tex groups. CONCLUSIONS This experimental model has shown that Oxiplex and Gore-Tex are effective methods to prevent peridural fibrosis and dural adhesions at the postlaminectomy areas.

Effectiveness of FK506 on lipid peroxidation in the spinal cord following experimental traumatic injury.

Study design:An in vivo study in Wistar albino rats with injured spinal cord.SettingDepartment of Neurosurgery, Biochemistry and Pathology, Gazi University, Ankara, Turkey.Objectives:The aim of this study was to investigate and compare the effects of FK506 an immunosupressive agent with methylprednisolone (MP) on lipid peroxidation (LP) in injured spinal cord tissue.Method:A total of 28 adult healthy Wistar albino rats were subjected to traumatic spinal cord injuries (SCI) by using an aneurysmal clip compression technique, and they were divided into four groups. The G1 group (n=8) received FK506 (1 mg/kg); the G2 group (n=8) received FK506 (1 mg/kg) and MP (30 mg/kg); the G3 group (n=6) received only MP (30 mg/kg); and the G4 group (n=6) received no medication. The injured spinal cord tissue was studied by means of lipid peroxides, malondialdehyde (MDA), with thiobarbituric acid reaction and additionally the FK506 (G1); the MP (G3) groups were studied for histopathologic alterations 72 h after SCI with eight separate animals.Results:Although LP values of G1, G2, G3 showed no statistical difference between intergroup analyses (P=0.547), a histopathological examination revealed that in the group that received MP, the oedema pattern was more significant than the group that received FK506. Another interesting finding was the presence of polymorphonuclear leucocytes in the MP group, whereas no infiltration was found in the FK506 group.Conclusion:Analysis of the results indicated that FK506 is a valuable pharmacological agent that could be used to decrease the LP and polymorphonuclear leucocyte infiltration and inflamatory reactions in the injured spinal cord tissue.

Effects of curcumin on acute spinal cord ischemia-reperfusion injury in rabbits. Laboratory investigation.

OBJECT The object of this study was to conduct a prospective, randomized, laboratory investigation of the neuroprotective effects of curcumin functionally, biochemically, and histologically in an experimental acute spinal cord ischemia-reperfusion injury on rabbits. METHODS Eighteen rabbits were randomly assigned to 1 of 3 groups: the sham group, the ischemia-reperfusion group, or the curcumin group. Spinal cord ischemia was induced by applying an infrarenal aortic cross-clamp for 30 minutes. At 48 hours after ischemia, neurological function was evaluated with modified Tarlov criteria. Biochemical changes in the spinal cord and plasma were observed by measuring levels of malondialdehyde (MDA), advanced oxidation protein products (AOPP), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), nitrite/nitrate, and tumor necrosis factor-α (TNF-α). Histological changes were examined with H & E staining. Immunohistochemical staining with antibodies against caspase-3 was performed to evaluate cell apoptosis after ischemia. RESULTS In the curcumin group, neurological outcome scores were statistically significantly better compared with the ischemia-reperfusion group. In the ischemia-reperfusion group, MDA, AOPP, and nitrite/nitrate levels were significantly elevated in the spinal cord tissue and the plasma by the induction of ischemia-reperfusion. The curcumin treatment significantly prevented the ischemia-reperfusion-induced elevation of nitrite/nitrate and TNF-α. In addition, the spinal cord tissue and the plasma SOD, GSH, and CAT levels were found to be preserved in the curcumin group and not statistically different from those of the sham group. Histological evaluation of the tissues also demonstrated a decrease in axonal damage, neuronal degeneration, and glial cell infiltration after curcumin administration. CONCLUSIONS Although further studies including different dose regimens and time intervals are required, curcumin could attenuate a spinal cord ischemia-reperfusion injury in rabbits via reducing oxidative products and proinflammatory cytokines, as well as increasing activities of antioxidant enzymes and preventing apoptotic cell death.

Split-cord malformation and tethered cord associated with immature teratoma

Case reportWe report a case of a 12-month-old boy with split-cord malformation, tethered cord, and intradural immature teratoma containing immature nephroblastic tissue. He also had a horseshoe kidney. OutcomeSurgical removal of the teratoma and tethered cord resulted in functional improvement of the existing bladder dysfunction. DiscussionTo our knowledge, such a case has not been reported before.