Murat Cosar

The influence of dexmedetomidine on ischemic rat hippocampus

In our study, we evaluated the neuroprotective effects of dexmedetomidine on oxidant-antioxidant systems, pro-inflammatory cytokine TNF-alpha and number of apoptotic neurons on hippocampus and dentate gyrus after transient global cerebral I/R injury. Eighteen rats divided into 3 groups, equally. Group I rats were used as shams. For group II and III rats, they were prepared for transient global cerebral ischemia using a four-vessel-occlusion model. 5 mL/kg/h 0.9% sodium chloride was infused to the Group II and 3 microg/kg/h/5 ml dexmedetomidine was infused to the Group III for 2 h after I/R injury. The levels of MDA and NO and activities of SOD and CAT were measured in the left hippocampus tissue. The levels of TNF-alpha concentration were measured in the plasma. The number of apoptotic neurons was counted by TUNNEL method in histological samples of right hippocampus tissue. MDA and NO levels increased in Group II compared with Group I rats (p=0.002, p=0.002, respectively). In group III, MDA and NO levels decreased as compared to Group II (p=0.015, p=0.002, respectively). SOD and CAT activities increased in Group III as compared to Group II rats (p=0.002, p=0.002, respectively). The decrease in TNF-alpha levels of group III was significant as compared to group II (p=0.016). The number of apoptotic neurons in group III was lower than Group II rats. Our study showed that dexmedetomidine has a neuroprotective effect on hippocampus and dentate gyrus of rats after transient global cerebral I/R injury.

The neuroprotective effect of dexmedetomidine in the hippocampus of rabbits after subarachnoid hemorrhage.

BACKGROUND Subarachnoid hemorrhage is a serious condition, often accompanied by cerebral vasospasm, which may lead to brain ischemia and neurologic deterioration. We evaluated if dexmedetomidine has neuroprotective effects in the hippocampus of vasospastic SAH rabbits or not. MATERIALS AND METHODS Eighteen New Zealand rabbits were taken. An experimental SAH model was formed by injecting 0.9 mL of autologous arterial blood per 1 kg of body weight to the cisterna magna of 12 rabbits. Craniotomy was performed in the control group (n = 6) except performing experimental SAH. Rabbits in the SAH-alone (n = 6) group were infused with 5 mL.kg(-1).h(-1) 0.9% sodium chloride, and rabbits (n = 6) in the SAH-dexmedetomidine group were infused with 5 microg.kg(-1).h(-1) dexmedetomidine for 2 hours, 48 hours after SAH was established. Rabbits of all groups were sacrificed via penthotal 24 hours after dexmedetomidine administration. Brains were removed immediately, and hippocampal tissues were blocked from the right hemisphere for histopathologic study. In addition to this, hippocampal tissues of left hemispheres were dissected for biochemical analyses to evaluate MDA levels, activity of XO, and SOD. RESULTS The histopathologic study showed that dexmedetomidine may have a neuroprotective effect in SAH-induced hippocampal injuries. The biochemical parameters support the neuroprotective effect of dexmedetomidine (P < .05). CONCLUSION Our study showed that dexmedetomidine may have a neuroprotective effect in the hippocampus of vasospastic SAH rabbits.

The major complications of transpedicular vertebroplasty.

OBJECT Vertebroplasty is a well-known technique used to treat pain associated with vertebral compression fractures. Despite a success rate of up to 90% in different series, the procedure is often associated with major complications such as cord and root compression, epidural and subdural hematomas (SDHs), and pulmonary emboli, as well as other minor complications. In this study, the authors discuss the major complications of transpedicular vertebroplasty and their clinical implications during the postoperative course. METHODS Vertebroplasty was performed in 12 vertebrae of 7 patients. Five patients had osteoporotic compression fractures, 1 had tumoral compression fractures, and 1 had a traumatic fracture. Two patients had foraminal leakage, 1 had epidural leakage, 1 had subdural cement leakage, 2 had a spinal SDH, and the last had a split fracture after the procedure. RESULTS Three patients had paraparesis (2 had SDHs and 1 had epidural cement leakage), 3 had root symptoms, and 1 had lower back pain. Two of the 3 patients with paraparesis recovered after evacuation of the SDH and subdural cement; however, 1 patient with paraparesis did not recover after epidural cement leakage, despite cement evacuation. Two patients with foraminal leakage and 1 with subdural cement leakage had root symptoms and recovered after evacuation and conservative treatment. The patient with the split fracture had no neurological symptoms and recovered with conservative treatment. CONCLUSIONS Transpedicular vertebroplasty may have major complications, such as a spinal SDH and/or cement leakage into the epidural and subdural spaces, even when performed by experienced spinal surgeons. Early diagnosis with CT and intervention may prevent worsening of these complications.

The protective effect of fish n-3 fatty acids on cerebral ischemia in rat prefrontal cortex

This study presents neuroprotective effects of fish n-3 EFA on the prefrontal cortex after cerebral ischemia and reperfusion. Eighteen rats divided into three groups. Group A rats were used as control. Cerebral ischemia and reperfusion was produced in rats either on a standard diet (Group B) or a standard diet plus fish n-3 EFA for 14 days (Group C). The malondialdehyde (MDA) levels and activities of superoxide dismutase (SOD) and catalase (CAT) were measured and the number of apoptotic neurons was counted. The levels of MDA and activities of SOD increased in Group B rats as compared to Group A rats, and decreased in Group C rats as compared to Group B rats. The activities of CAT increased in Group C as compared to Group B rats. The number of apoptotic neurons in the prefrontal cortex was lower in Group C as compared to Group B rats.

Intradiploic epidermoid cysts of the skull: a report of four cases.

Epidermoid cysts are uncommon, benign and slow-growing lesions. They may often reach an enormous size without producing neurological symptoms. Intradiploic epidermoid cysts are nearly 25% of all epidermoids. They are derived from ectodermal remnants that stay within the cranial bones during embryonic development. Intradiploic epidermoid cysts can be located in any part of the skull. Two of our four cases were located in left occipital bone and the others were in the frontal bone. These tumours can occur at any age from the first to the seventh decade of life. Our cases had a mean age of 38.75 years (19-55 years). They may reach great sizes before the initial diagnosis and may produce major neurological signs. For good long-term prognosis, correct radiological assessment and complete removal of the tumour with its capsule are essential. We report four cases of intradiploic epidermoid cysts of the skull and analyse the clinical, radiological features and treatment of these lesions in the light of relevant literature.

Recurrent solitary fibrous tumour in the cerebellopontine angle.

Solitary fibrous tumours (SFT) of the central nervous system are rare. They resemble meningioma in clinical presentation, imaging features and appearance at surgery. Schwannoma, hemangiopericytoma and other spindle cell mesenchymal neoplasms should also be considered in the differential diagnosis. Although the histogenesis of this tumour is still debated, strong CD34 reactivity of the tumour cells suggests that SFT is mesenchymal. We present the clinical, radiological, and pathological features of an SFT located in the cerebellopontine angle (CPA). A 55-year-old female presented with 6 months of headache. The MRI scan showed a contrast enhancing ovoid mass in the left CPA. At craniotomy, the tumour was completely resected. Histolopathological diagnosis was of meningioma. Three years later, the symptoms recurred and an MRI scan demonstrated tumour recurrence. A repeat craniotomy was performed and the lesion was again completely excised. Tumour morphology on histopathology and immunoreactivity for CD34 of the tumour cells supported the diagnosis of SFT. Review of the original tumour also disclosed immunoreactivity for CD34. Ki67 labeling indices were less than 1% in both tumours.

The neuroprotective effect of fish n-3 fatty acids in the hippocampus of diabetic rats

Abstract Introduction: Diabetes mellitus may lead to functional and structural changes in the brain. Fish oil is a rich source of n-3 essential fatty acids (EFA) such as eicosapentaenoic and docosahexoenoic acids. We examined the neuroprotective effects of fish n-3 EFA in the hippocampus of diabetic rats. Materials and methods: Nineteen adult male rats were divided into three groups. Group I (control; n = 6) was fed a normal rat diet. Group II (diabetic; n = 6) was fed a normal rat diet and streptozotocin (STZ) was administered to induce diabetes mellitus. Group III (n-3 + diabetic; n = 7) was fed a normal rat diet and fish n-3 EFA (Marincap®, 0.4 g/kg/day) for 8 weeks and STZ was administered to induce diabetes mellitus. The levels of malondialdehyde (MDA) and activities of superoxide dismutase (SOD) and catalase (CAT) were measured in the left hippocampus after the animals were sacrificed. The right hemisphere was completely blocked. The sections were stained with Cresyl Violet and apoptotic neurons were counted in the hippocampus. Results: The levels of MDA and activities of SOD and CAT increased in diabetic rats compared to control rats. However, the levels of MDA and activities of SOD and CAT decreased in n-3 + diabetic rats compared to diabetic rats. Also, the number of apoptotic neurons increased in diabetic rats compared to control rats and decreased in n-3 + diabetic rats compared to diabetic rats. Conclusions: Fish n-3 EFA reduces oxidative stress and induces apoptotic changes in the hippocampus of STZ-diabetic rats. The addition of fish n-3 EFA to diets may be useful to prevent functional and structural changes to cerebral centers due to diabetes mellitus.

Primary meningioma of the paranasal sinus.

We report a 17 year old man with a primary ectopic meningioma in the right ethmoid and maxillary sinus. He underwent endoscopic surgery. After total removal of the tumour his subsequent clinical course was good. The clinical and pathologic features of the 32 previously reported cases in the literature are also reviewed. The pathogenesis and treatment of primary paranasal sinus meningioma is briefly discussed.

Neuroprotective Effect of Humic Acid on Focal Cerebral Ischemia Injury: an Experimental Study in Rats

Stroke is still a major cause of death and permanent neurological disability. As humic acids are well-known antioxidant molecules, the purpose of this study was to investigate the potential neuroprotective effects of humic acid in a focal cerebral ischemia model. Twenty-four rats were divided equally into three groups. A middle cerebral artery occlusion model was performed in this study where control (group II) and humic acid (group III) were administered intraperitoneally following an ischemic experimental procedure. Group I was evaluated as sham. Malondialdehyde (MDA), superoxide dismutase (SOD), and nuclear respiratory factor-1 (NRF-1) levels were analyzed biochemically on the right side of the ischemic cerebral hemisphere, while ischemic histopathological studies were completed on the left side to investigate the antioxidant status. Biochemical results showed that SOD and NRF-1 levels were significantly increased in the humic acid group (III) compared with the control group (II) while MDA levels were significantly decreased. On histopathological examination, cerebral edema, vacuolization, degeneration, and destruction of neural elements were decreased in the humic acid group (III) compared with the control group (II). Cerebral ischemia was attenuated by humic acid administration. These observations indicate that humic acid may have potential as a therapeutic agent in cerebral ischemia by preventing oxidative stress.

The Results of ??-tricalcium Phosphate Coated Hydroxyapatite (??-TCP/HA) Grafts for Interbody Fusion After Anterior Cervical Discectomy

Study Design The efficacy of tricalcium phosphate and hydroxyapatite (β-TCP/HA) grafts was studied after anterior cervical discectomy (ACD). Objective This study presents our observations about the efficacy of β-TCP/HA grafts after ACD. Summary of Background Data Especially in the last 2 decades, fusion materials such as autograft and allograft, as well as different kind of cages were used to maintain fusion after ACD. Methods β-TCP/HA grafts after ACD were used in 17 patients. The cervical and radicular pain was evaluated via visual analog scale (VAS) score preoperatively, at postoperative third week, and after 20 months (range: 18 to 24 mo) after the operation. The radiologic evaluations were done preoperatively, at postoperative first day and at the latest follow-up. The VAS, intervertebral space ratio, height of intervertebral disc space and neural foramen, and cervical and segmental lordosis angles were recorded preoperatively and during the postoperative follow-up period. The presence of fusion was controlled in computed tomography scans taken at the latest follow-up. Results Both clinical and radiologic evaluations yielded satisfactory results. VAS scores decreased significantly in all patients. The intervertebral space and neural foramen and intervertebral disc heights increased at postoperative day 1 but were found to be decreased at the latest follow-up (P<0.05). On the contrary the cervical and segmental lordosis angles decreased at postoperative day 1 but were found to be increased at the latest follow-up (P<0.05). There was a solid fusion in 16 out of 17 patients (94.11%). Conclusions Although there was a loss of the initially obtained neural foraminal and disc height, the application of β-TCP/HA graft after ACD resulted in a high rate of fusion and patient satisfaction. Additionally, the cervical and segmental lordosis was preserved. We concluded that it is a good alternative to current methods to maintain cervical alignment and fusion after ACD.