Oguz Cataltepe

Anatomical studies of DNA fragmentation in rat brain after systemic kainate administration

Rats treated systemically with kainate develop stereotyped epileptic seizures involving mainly limbic structures that may last for hours. This model of limbic status epilepticus has been widely studied using classical neuropathological techniques. We used in situ nick translation histochemistry to examine patterns of DNA fragmentation in this model. We found a stereotyped and reproducible pattern of neuronal populations that demonstrate evidence of DNA fragmentation from 24 h to one week after kainate treatment. Neither blockade of new protein synthesis nor blockade of the N-methyl-D-aspartate-type glutamate receptors significantly altered this response. Moreover, we saw no evidence of the regular internucleosomal cleavage of DNA that produces a characteristic laddered appearance of 180-200 bp DNA fragments after gel electrophoresis in samples obtained from microdissected affected regions. These studies suggest that DNA fragmentation after systemic kainate-induced seizures is not the result of programmed cell death. This assay may be useful for quantitative testing of both neuroprotective agents and mechanistic hypotheses.

Tectal Gliomas in Children: The Implications for Natural History and Management Strategy

Tumors involving the tectal region constitute a distinct subgroup of brain stem gliomas with an indolent clinical course. Here, we present the clinical and neuroradiologic features of 9 children with tectal tumors. All patients presented with signs and symptoms of hydrocephalus and were managed with ventriculoperitoneal shunt insertion. MRI studies revealed focal hyperintense lesions on T2-weighted images without any contrast enhancement, and no evidence of progression was demonstrated in any patient. We also reviewed the published series of tectal gliomas in the literature to compare with our results. Based on these and other published series, it was concluded that intrinsic tectal gliomas of childhood with sizes less than 2 cm in diameter and without any tumor extension or contrast enhancement constitute a specific subgroup of tectal masses which rarely display invasive clinical behavior and should be managed conservatively. CSF diversion procedures and long-term yearly follow-up examinations with MRI scans are sufficient in these patients.

Effect of status epilepticus on hypoxic-ischemic brain damage in the immature rat

ABSTRACT: Seven-day postnatal rats were subjected to unilateral common carotid artery ligation, 3 h after which they were subjected to hypoxia with 8% oxygen at 37°C for 2 h. Thereafter, they received multiple s.c. injection(s) of bicuculline (6 mg/kg) adequate to produce behaviorally apparent siezures lasting greater than 1 h (status epilepticus). Repeated episodes of status epilepticus at 2, 6, and 12 h of recovery from hypoxia-ischemia (III) produced a mortality rate of 53%. Among the survivors, there was no statistically significant difference in the extent of brain damage between convulsing and nonconvulsing HI controls, analyzed at 30 d of age. Histopathologic examination for acute lesions also indicated no difference in the severity of brain damage between dead and surviving rat pups subjected to status epilepticus, indicating that mortality was not related to the severity of prior HI brain damage. Those immature rats that died during status epilepticus exhibited lower blood glucose concentrations (1.75 ± 0.35 mmol/L) compared with surviving, convulsing animals (4.25 ± 0.51 mmol/L; p - 0.016). Glucose supplementation (0.1 mL of 50% glucose) early during status epilepticus improved survival and significantly prolonged scizure activity (90 ± 14 min) compared with nonglucose treated, convulsing littermates (47 ± 10 min; p - 0.02). Glucose supplementation did not increase the extent of brain damage despite improved survival and increased duration of seizure activity. The findings indicate that even repetitive episodes of status epilepticus in immature rats previously subjected to cerebral HI do not accentuate brain damage despite a substantial mortality. Hypoglycemia contributes to death arising from status epilepticus, and both survival and seizures can be prolonged by glucose supplementation without risk of increasing the severity of any existing brain damage.

Cerebrospinal fluid concentrations of glutamate and GABA during perinatal cerebral hypoxia-ischemia and seizures.

Cerebrospinal fluid (CSF) concentrations of glutamate and gamma- aminobutyric acid (GABA), as estimates of levels in the extracellular compartment of brain, were determined in 7-day postnatal rats at the terminus of hypoxia-ischemia and during status epilepticus, induced with bicuculline, at 2 and 24 h of recovery. Hypoxia-ischemia was associated with increased CSF glutamate, which was not increased further during status epilepticus. In contrast, CSF GABA was increased by hypoxia-ischemia as well as by status epilepticus during recovery. CSF glutamate/GABA ratios in rat pups subjected to status epilepticus with or without prior hypoxia-ischemia were lower than control animals during recovery. The lack of any significant increase in glutamate or in the glutamate/GABA ratio during status epilepticus would preclude any neuronal injury from occurring in those immature rats sustaining seizures alone or any accentuation of brain damage in those animals subjected to prior cerebral hypoxia-ischemia.

Fatty acid binding protein 4 is expressed in distinct endothelial and non-endothelial cell populations in glioblastoma

O. Cataltepe, M. C. Arikan, E. Ghelfi, C. Karaaslan, Y. Ozsurekci, K. Dresser, Y. Li, T. W. Smith and S. Cataltepe (2012) Neuropathology and Applied Neurobiology38, 400–410

Primary multiple cerebral hydatid cysts.

Primary multiple cerebral hydatid cysts are extremely rare: In this paper, an 8-year-old male patient who has one primary cerebral hydatid cyst in each cerebral hemisphere is presented. CT findings and operation are discussed. The literature is reviewed and the incidence of multiple cerebral hydatid cyst is compared with the published reports.

Dense epidermoid cyst of the cerebellopontine angle.

SummaryA case of epidermoid cyst in the cerebellopontine angle which appeared as a hyperdense mass on CT is presented with clinical and radiological features. The preoperative tentative diagnosis proved erroneous. The literature is reviewed on this exceptinally rare radiological finding of epidermoid cysts and highlights of preoperative diagnosis are discussed.

Aneurysmal bone cyst of the frontal bone

Aneurysmal bone cyst rarely affects the skull. We report two cases of aneurysmal bone cyst of the frontal bone. One of the cases is associated with pregnancy. The association of pregnancy with aneurysmal bone cyst and enlargement of the aneurysmal bone cyst during the pregnancy have been discussed.

An unusual dural arterio venous fistula in an infant

Dural arteriovenous fistula, (AVF), a rare entity, presents most commonly in adults. An 11-month-old boy presented with symptoms of congenital toxoplasmosis associated with an extensive dural AVF of the torcular Herophili and bilateral occulusion of the transverse and sigmoid sinuses. His intracranial venous drainage had become rerouted via the cavernous sinuses to the ophthalmic veins. The relationship of toxoplasmosis and sinus thrombosis to the pathogenesis of dural AVF and their clinical and radiological features are discussed.

Arterial Bridging for Repair of Peripheral Nerve Gap: a Comparative Study

SummaryA new experimental model was designed in which the regeneration of rat femoral nerve across a 8 mm excised gap was investigated after insertion of the distal and proximal stumps into the anatomically and functionally intact femoral artery (AIAB). This model was compared with groups of free artery and autologous nerve grafting. After a period of 12 weeks, a histological and electrophysiological analysis was carried out, which demonstrated that the AIAB and autologous nerve grafting group had a significantly higher percentage of regeneration compared with the free artery-graft group. The nerve regeneration and intraneural vascular reconstruction that occured within AIAB group were more successful than those that occured in the artery and nerve-grafting groups.