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    G. Bozkurt

    In this study we investigated whether pretreatment with melatonin was protective against the injury of the central nervous system (CNS) in rats receiving LD(50) whole body irradiation. The wistar rats were randomized into four groups: i)... more
    In this study we investigated whether pretreatment with melatonin was protective against the injury of the central nervous system (CNS) in rats receiving LD(50) whole body irradiation. The wistar rats were randomized into four groups: i) the control group (CG), ii) melatonin-administered group (MG; 1 mg/kg body weight), iii) irradiated group (RG; 6.75 Gy, one dose), and iv) melatonin-administered and irradiated group (MRG). Blood samples were drawn from the rats 24 h after the treatment and plasma glutathione levels were assayed. Plasma glutathione level was significantly higher in RG than CG. The melatonin pretreatment prevented GSH increase induced by irradiation. Lipid peroxidation and glutathione levels of rat cerebral cortex were determined in all groups after 24 h. Cortical malondialdehyde (MDA) was significantly higher in the RG. The melatonin pretreatment prevented cortical MDA increase induced by irradiation. Cortical GSH was significantly lower in RG than the CG. The melat...
    Randomized controlled. To evaluate the effects of Tamoxifen (TMX) and trifluoperozine (TFP) on pinealectomized chicken scoliosis. Pinealectomized chicken develops scoliosis probably due to the lack of melatonin. In addition to other... more
    Randomized controlled. To evaluate the effects of Tamoxifen (TMX) and trifluoperozine (TFP) on pinealectomized chicken scoliosis. Pinealectomized chicken develops scoliosis probably due to the lack of melatonin. In addition to other functions, melatonin also acts as a calmodulin antagonist. We postulate that loss of this antagonistic effect may be the cause of scoliosis in this model. TMX and TFP are known calmodulin antagonists, which may alter the incidence and severity of scoliosis. Seventy-two newly hatched chicken that underwent surgical pinealectomy within 72 hours of hatching were divided into 3 groups of 24 animals in each as group I (control), group II (TMX), and group III (TFP). TMX and TFP were given to groups II and III, respectively, for 10 weeks with the dose of 0.1 mg/kg/d, whereas the control group received no medication. AP scoliosis radiographs were obtained at seventh and 10th week to evaluate coronal spinal alignment. Three chickens in group I, 2 chickens in group II, and 1 chicken in group III died in the first postoperative week. Scoliosis incidences and magnitudes were similar among groups at seventh and 10th week. TMX and TFP groups showed decreases of incidence of upper cervical, lower cervical, lower cervical-thoracic-lumbar curves at 10th week compared with seventh week. TMX group showed a decline in thoracic region mean Cobb angle, whereas control group showed an increase (P = 0.048). TMX group showed a more prominent decline in cervicothoracic region mean Cobb angle compared with control group (P = 0.009). The incidence and magnitude of scoliosis in pinealectomized chicken may be decreased by the administration of TMX, presumably because of this drugs' calmodulin antagonism. Further studies on higher animals and dosage and timing are required.
    Turkish Neurosurgery.
    OBJECTIVE: Aging, expressing postmaturational changes, is a process that contains a decline in the organism's simultaneous and harmonic response, adaptation potential, and resistance ability to external and negative events (stressors... more
    OBJECTIVE: Aging, expressing postmaturational changes, is a process that contains a decline in the organism's simultaneous and harmonic response, adaptation potential, and resistance ability to external and negative events (stressors and stimuli). The free radical theory of ...
    Discussion The frequency that of an acquired abducens nerve paresis is due to an intracranial aneurysm is between 3.3% and 3.6%[4]. Isolated or combined pareses of the abducens nerve may be seen with aneurysms of infraclinoid internal... more
    Discussion The frequency that of an acquired abducens nerve paresis is due to an intracranial aneurysm is between 3.3% and 3.6%[4]. Isolated or combined pareses of the abducens nerve may be seen with aneurysms of infraclinoid internal carotid, ...
    Study design:Experimental investigation of intrathecal transplantation of stem cells by lumbar puncture (LP) in a rat model that simulates human thoracic spinal cord injury (SCI).Objectives:To examine the distribution and phenotype of... more
    Study design:Experimental investigation of intrathecal transplantation of stem cells by lumbar puncture (LP) in a rat model that simulates human thoracic spinal cord injury (SCI).Objectives:To examine the distribution and phenotype of spinal cord-derived neural stem/progenitor cells (NSPCs) and bone marrow-derived mesenchymal stromal cells (BMSCs) following LP transplantation in SCI rats.Setting:Toronto Western Research Institute, Toronto, Ontario, Canada.Methods:NSPCs or BMSCs were transplanted
    Randomized prospective study using an experimental scoliosis model in a pinealectomized chicken. To investigate the effect of the side of visual impairment on the incidence and laterality of the curves on a pinealectomized chicken model.... more
    Randomized prospective study using an experimental scoliosis model in a pinealectomized chicken. To investigate the effect of the side of visual impairment on the incidence and laterality of the curves on a pinealectomized chicken model. Visual impairment has been shown to increase the incidence of idiopathic-like scoliosis in human subjects when compared to the incidence of the general population. However, an association between the laterality of the visual impairment and incidence or laterality of scoliosis has not been established. A total of 60 newly hatched white leghorn chicks was divided equally into 3 study groups of no visual impairment (n = 20) (group 1), left-sided blindness by enucleation (n = 20) (group 2), and right-sided blindness (n = 20) (group 3). Pinealectomies and enucleations were performed on the second day after hatching. Anteroposterior radiographs were obtained at the 5th and 10th weeks, and the incidence, side, and magnitude of the resulting scoliotic curves were recorded. The pinealectomy model yielded a general scoliosis incidence of 60%. The occurrence of scoliosis was not different among the groups (65%, 55%, 60%, respectively, P = 0.812). The incidences at the 5th and 10th weeks were both 40%, as a result of the death of 6 chickens between the 5th and 10th weeks, as well as the appearance or disappearance of curves during this time, again not different among the groups. However, the laterality of the curves was significantly different (P = 0.045). The visually impaired groups tended to have left thoracic curves as frequently as the right thoracic curves (7 right and 4 left in group 2, and 7 right and 6 left in group 3), whereas in group 1, the thoracic curves were predominantly right sided (12 right and 1 left). The average magnitude of the curves was 30.47 degrees +/- 19.32 degrees , not significantly different among the groups (27.6 degrees +/- 16.7 degrees , 23.7 degrees +/- 21.5 degrees , 39.8 degrees +/- 17.7 degrees , respectively, P = 0.109). Unilateral visual impairment does not have a significant effect on the overall incidence and magnitude of scoliosis in the pinealectomized chicken. It does affect the laterality of the curves though, visually impaired subjects having a significantly higher likelihood of left thoracic curves, regardless of the side of blindness. It may be worthwhile to see if such an association is present in human beings as well.
    Epidermoid cysts may remain asymptomatic for a long period of time due to their slowly growing pattern corresponding with the normal human skin turnover time and due to soft and light cyst content. They do not cause compression of neural... more
    Epidermoid cysts may remain asymptomatic for a long period of time due to their slowly growing pattern corresponding with the normal human skin turnover time and due to soft and light cyst content. They do not cause compression of neural and vascular structures initially that is why almost all of the cases in the literature are diagnosed during adulthood. We report here an epidermoid cyst in childhood, which was located in the medulla oblongata, unusually and atypically with liquefied cyst content. The liquefaction may occur due to an intrauterine or early childhood infection. The reported case also suffered previously a severe respiratory infection. Although the cyst is located in and around a highly eloquent neural area, plasticity of the brain stem prevented neurological deterioration due to this very slow growing extraaxial mass lesion. The ordinary cyst content found in the center of the cyst cavity during the operation suggested that the same ordinary material, which was previously at the periphery, ran to get liquefied in time. We suggest that the symptoms of this present case appeared very early due to liquefaction of the cyst content with compression and displacement of the brain stem caudally. The recent infection process may predispose the pathological condition.
    The latex allergy is known as a very frequent problem of children with spina bifida (SB). The aim of this prospective study is to determine the frequency of latex sensitization and allergy in Turkish children with SB and to evaluate the... more
    The latex allergy is known as a very frequent problem of children with spina bifida (SB). The aim of this prospective study is to determine the frequency of latex sensitization and allergy in Turkish children with SB and to evaluate the related risk factors. We enrolled a total of 175 children and collected them in four groups of patients: children with SB, children who had neurosurgical disorders other than SB, atopic children with allergic diseases, and healthy children as control group. All cases were evaluated for latex sensitivity and allergy with skin prick tests and specific IgE. The diagnosis of latex allergy was confirmed with the latex provocation test. Ten children with SB, two children with other neurological disorders, and three atopic children with allergic disease were found "sensitized to latex". Among these sensitized children, only one child with SB had latex allergy. Multivariate logistic regression analysis of the children with SB and other neurologic disorders and the whole group of patients showed that skin test positivity, the presence of noncentral nervous system (CNS) surgery, and the number of the operations were significant risk factors for latex sensitization. Our study showed that rates of latex sensitivity and allergy in children with SB in Turkey are significantly lower than published rates in literature. We also found that atopy, the presence of non-CNS operations in children with SB and other neurologic disorder, and total number of operations in the whole group of patients are the most important risk factors for latex sensitization.