Zahir Kizilay

Effects of the hippocampal deep brain stimulation on cortical epileptic discharges in penicillin - induced epilepsy model in rats.

AIM Experimental and clinical studies have revealed that hippocampal DBS can control epileptic activity, but the mechanism of action is obscure and optimal stimulation parameters are not clearly defined. The aim was to evaluate the effects of high frequency hippocampal stimulation on cortical epileptic activity in penicillin-induced epilepsy model. MATERIAL AND METHODS Twenty-five Sprague-Dawley rats were implanted DBS electrodes. In group-1 (n=10) hippocampal DBS was off and in the group-2 (n=10) hippocampal DBS was on (185 Hz, 0.5V, 1V, 2V, and 5V for 60 sec) following penicillin G injection intracortically. In the control group hippocampal DBS was on following 8 μl saline injection intracortically. EEG recordings were obtained before and 15 minutes following penicillin-G injection, and at 10th minutes following each stimulus for analysis in terms of frequency, amplitude, and power spectrum. RESULTS High frequency hippocampal DBS suppressed the acute penicillin-induced cortical epileptic activity independent from stimulus intensity. In the control group, hippocampal stimulation alone lead only to diffuse slowing of cerebral bioelectrical activity at 5V stimulation. CONCLUSION Our results revealed that continuous high frequency stimulation of the hippocampus suppressed acute cortical epileptic activity effectively without causing secondary epileptic discharges. These results are important in terms of defining the optimal parameters of hippocampal DBS in patients with epilepsy.

Boric acid reduces axonal and myelin damage in experimental sciatic nerve injury

The aim of this study was to investigate the effects of boric acid in experimental acute sciatic nerve injury. Twenty-eight adult male rats were randomly divided into four equal groups (n = 7): control (C), boric acid (BA), sciatic nerve injury (I) , and sciatic nerve injury + boric acid treatment (BAI). Sciatic nerve injury was generated using a Yasargil aneurysm clip in the groups I and BAI. Boric acid was given four times at 100 mg/kg to rats in the groups BA and BAI after injury (by gavage at 0, 24, 48 and 72 hours) but no injury was made in the group BA. In vivo electrophysiological tests were performed at the end of the day 4 and sciatic nerve tissue samples were taken for histopathological examination. The amplitude of compound action potential, the nerve conduction velocity and the number of axons were significantly lower and the myelin structure was found to be broken in group I compared with those in groups C and BA. However, the amplitude of the compound action potential, the nerve conduction velocity and the number of axons were significantly greater in group BAI than in group I. Moreover, myelin injury was significantly milder and the intensity of nuclear factor kappa B immunostaining was significantly weaker in group BAI than in group I. The results of this study show that administration of boric acid at 100 mg/kg after sciatic nerve injury in rats markedly reduces myelin and axonal injury and improves the electrophysiological function of injured sciatic nerve possibly through alleviating oxidative stress reactions.

Anterior spinal cord herniation after multilevel anterior cervical corpectomy: A case report.

Many complications related to the resection of an ossified posterior longitudinal ligament via the anterior approach have been reported. Postoperative neurological deterioration is one such complication that may appear due to massive anterior spinal cord herniation related to a dural defect following resection of the ossified posterior longitudinal ligament. Specifically, spinal cord herniations have been reported to be associated with posterior approaches, and a large number of theories regarding this association have been offered by various authors. However, anterior spinal cord herniation is extremely rare, and its pathophysiology has not yet been explained. In this case report, we report a male patient who experienced anterior spinal cord herniation following anterior surgery. Spinal cord herniation may develop following the removal of the anterior cervical corpectomy. Therefore, surgeons should be aware of this condition when planning treatments for cervical spondylotic myelopathy via the anterior approach.

Symptomatic pneumocephalus after lumbar disc surgery: a case report.

Symptomatic pneumocephalus is frequently seen after traumatic fracture of the skull base bone. However, it has rarely been reported after spinal surgery and its mechanism has not been fully explained. In this paper, we present a 30 year old male patient who had lumbar discectomy due to a symptomatic midline lumbar disc herniation. He had developed symptomatic pneumocephalus after the lumbar disc surgery associated with application of a vacuum suction device. We present and discuss our patient in the light of the literatures.

Effect of etanercept on the formation of epidural fibrosis in an experimental model

AIM To investigate the effects of local and systemic administration of etanercept on the formation of epidural fibrosis. MATERIAL AND METHODS Twenty-eight rats were randomly divided into four equal groups (Control, SpongostanTM, Local etanercept and Systemic etanercept) and laminectomy was performed between T11 and L1 in all rats. SpongostanTM was soaked with saline (0.1 mg/kg), local etanercept (300 ?g/kg) was applied with SpongostanTM and systemic etanercept (300 ?g/kg/week) was applied subcutaneously. Four weeks later, the vertebral column from T9 to L3, including the paraspinal muscles and epidural scar tissue, was removed en bloc, and epidural fibrosis and arachnoidal involvement were graded and evaluated histopathologically. RESULTS The grading of epidural fibrosis was statistically significantly lower in systemic and local administration of etanercept groups compared to the control group (p < 0.005), but systemic etanercept administration was more effective. CONCLUSION Systemic administration of etanercept can be effective in reducing epidural fibrosis in rats after laminectomy.

The Effects of Rifampin, Povidone-Iodine and Hydrogen Peroxide on the Formation of Epidural Fibrosis in the Experimental Epidural Fibrosis Model

The aim of the study was to determine the effect of direct application of rifampin, povidone-iodine, and hydrogen peroxide on the formation of epidural fibrosis in rats. Forty-eight adult male Wistar albino rats were equally and randomly divided into four groups (laminectomy, topical rifampin, topical povidone-iodine, and topical hydrogen peroxide). Laminectomy was performed at the T12 level in all rats. Four weeks later, the extent of epidural fibrosis was assessed both macroscopically and histopathologically. ANOVA test was used for the evaluation of dural thickness. Kruskal-Wallis test was used for the pathology and macroscopic evaluation. Chi-square test was used for evaluation of the arachnoid involvement. p value <0.05 was accepted as statistically significant. Our data revealed that topical application of both povidone-iodine and hydrogen peroxide were effective in reducing epidural fibrosis formation. The results of our study provide the experimental evidence of the preventive effects of topical application of povidone-iodine and hydrogen peroxide over epidural fibrosis.

Effect of systemic application of bone marrow-derived mesenchymal stem cells on healing of peripheral nerve injury in an experimental sciatic nerve injury model

AIM To investigate the effects of systemic application of bone marrow-derived mesenchymal stem cells in a compression model of peripheral nerve injury. MATERIAL AND METHODS 24 male Wistar albino rats were randomly divided into 3 equal groups (n=8):Control (C),injury (I),and stem cell and injury (SI).The sciatic nerve of rats in the I and SI groups was subjected to clip compression for 5 minutes.Moreover,approximately 5x105 bone marrow-derived mesenchymal stem cells were given via tail vein of the rats in the SI group immediately after clip compression. The nerve conduction velocities and amplitudes of the rats were measured 30 days later.Then,the sciatic nerves were removed, and myelin damage grading and axon counting were performed.The data were analyzed by One-Way ANOVA and Tukey\s post-hoc test.P values less than 0.05 were considered to be statistically significant. RESULTS While the proximal,distal and mean latency values were higher in the I and SI groups than in the control group,the same measurements were lower in the SI group than in the I group.While the nerve conduction velocity,the compound action potential and the number of axons were lower in the I and SI groups than in the control group,the same measurements were higher in the SI group than in the I group.Moreover,myelin damage was found to be lower in the SI group than in the I group. CONCLUSION It has been shown that systemic application of bone marrow-derived mesenchymal stem cells in a compression model of peripheral nerve injury has a positive impact on both myelin sheath and axon survival.

Ozone Partially Decreases Axonal and Myelin Damage in an Experimental Sciatic Nerve Injury Model

ABSTRACT Aim: To investigate the effects of ozone in experimental acute sciatic nerve injury. Material and Methods: Twenty-eight male rats were divided into four groups (n = 7): control (C), ozone (O), injury (SNI), and treatment with ozone after injury (SNI + Ozone). Sciatic nerve injury was generated by compressing the right sciatic nerve for 90 s using a Yasargil aneurysm clip in groups SNI and SNI + Ozone. A 70 µg/ml concentration of ozone was given four times (once a day at 1st, 24th, 48th, and 72th h) at a dose of 0.5 mg/kg to groups O and SNI + Ozone after injury by an intraperitoneal injection. Nerve conduction velocities of all rats were measured by in vivo electrophysiological tests at the end of the day 4. Then, plasma malondialdehyde, total oxidant and antioxidant status were measured and also axonal and myelin changes in sciatic nerves of histopathological examination were performed. The data were analyzed by Kolmogorov Smirnov test, Mann–Whitney U-test, and Chi square test. p <.05 was considered statistically significant. Results: The proximal and distal latency difference were higher and nerve conduction velocity were lower in SNI group than C and O groups, and the myelin structure was found to be broken in group SNI compared to groups C and O. However, the amplitude of the compound action potential, the nerve conduction velocity were significantly higher in group SNI + Ozone than in group SNI. Moreover, myelin injury was significantly lower in group SNI + Ozone compared to group SNI. Total oxidant status in group SNI was significantly higher than in groups C, O, and SNI + Ozone. But, total antioxidant status in group SNI was significantly lower than in groups C, O, and SNI + Ozone. Conclusion: This study showed that the administration of ozone at a dose of 0.5 mg/kg after peripheral nerve injury in rats reduces myelin and axonal injury.

Effect of Methyl Palmitate on the Formation of Epidural Fibrosis in an Experimental Epidural Fibrosis Model

ABSTRACT Aim: To investigate the effects of local and systemic administration of methyl palmitate on the formation of epidural fibrosis. Material and Methods: Twenty-eight rats were randomly divided into four equal groups (control, Spongostan, local methyl palmitate and orally methyl palmitate) and laminectomy was performed between T11 and L1 in all rats. Local methyl palmitate (300 mg/kg) was applied with Spongostan; methyl palmitate (300 mg/kg) was given orally three times per week on different days for a total period of 4 weeks. Four weeks later, the vertebral column from T9 to L3, including the paraspinal muscles and epidural scar tissue, was removed en bloc and epidural fibrosis and arachnoidal involvement was graded and evaluated histopathologically. Kruskal-Wallis and Pearson Chi-Square test were used for statistical analysis. A statistically significant p-value was determined as p < 0.05. Results: The grading of epidural fibrosis was lower at a statistically significant level in orally-administrated methyl palmitate groups compared to the control and spongostan groups (p < 0.05). Conclusion: The findings of this study show that oral methyl palmitate decreases the formation of epidural fibrosis and that this effect of methyl palmitate could be mediated by reducing the functions of inflammatory cells such as macrophages, neutrophils and fibroblasts, including anti-inflammatory and antioxidant effects.

Pure Motor Stroke Secondary to Cerebral Infarction of Recurrent Artery of Heubner after Mild Head Trauma: A Case Report

BACKGROUND: The recurrent Heubner’s artery is the distal part of the medial striate artery. Occlusion of the recurrent artery of Heubner, classically contralateral hemiparesis with fasciobrachiocrural predominance, is attributed to the occlusion of the recurrent artery of Heubner and is widely known as a stroke syndrome in adults. However, isolated occlusion of the deep perforating arteries following mild head trauma also occurs extremely rarely in childhood. CASE REPORT: Here we report the case of an 11-year-old boy with pure motor stroke. The brain MRI showed an acute ischemia in the recurrent artery of Heubner supply area following mild head trauma. His fasciobrachial hemiparesis and dysarthria were thought to be secondary to the stretching of deep perforating arteries leading to occlusion of the recurrent artery of Heubner. CONCLUSION: Post-traumatic pure motor ischemic stroke can be secondary to stretching of the deep perforating arteries especially in childhood.