• Journal of Korean Neurosurgical Society
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• v.29 no.7
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• pp.861-867
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• 2000

Purpose : Neuronal migration disorder(NMD) is a major underlying pathology of patients with intractable epilepsy. The role of NMD on seizure susceptibility or epileptogenecity, however, has not been documented. Methods : External irradiation of total amount of 250 cGY was performed to the fetal rats on days 16(E16) and 17(E17) of gestation. After delivery, the rats of 230-260g were decapitated for the histopathologic study. Epileptog-enecity of the NMD was studied by observing electroclinical events after intraperitoneal kainic acid(KA) injection in the control rats and NMD rats. Results : Histopathologic findings revealed focal and/or diffuse cortical dysplasia consisting of dyslamination of the cerebral cortex and appearance of the cytomegalic neurons, neuronal heterotopia in the periventricular white matter, dispersion of the pyramidal layer and the dentate gyrus of the hippocampus, and agenesis of the corpus callosum. Abnormal expression of neurofilaments protein(NF-M/H) was characteristically observed in the dysplastic neurons of the neocortex and hippocampus. Early ictal onset and prolonged ictal activity on EEG and clinical seizures were observed from the NMD rats unlike with the control rats. Conclusions : Exteranl irradiation on the fetal rats produced NMD. And the rats with NMD were highly susceptible to kainic acid provoked seizures. This animal model would be useful to study the pathophysiology of clinically relevant NMDs.

• Clinical and Experimental Pediatrics
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• v.56 no.10
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• pp.431-438
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• 2013

Magnetoencephalography (MEG) records the magnetic field generated by electrical activity of cortical neurons. The signal is not distorted or attenuated, and it is contactless recording that can be performed comfortably even for longer than an hour. It has excellent and decent temporal resolution, especially when it is combined with the patient's own brain magnetic resonance imaging (magnetic source imaging). Data of MEG and electroencephalography are not mutually exclusive and it is recorded simultaneously and interpreted together. MEG has been shown to be useful in detecting the irritative zone in both lesional and nonlesional epilepsy surgery. It has provided valuable and additive information regarding the lesion that should be resected in epilepsy surgery. Better outcomes in epilepsy surgery were related to the localization of the irritative zone with MEG. The value of MEG in epilepsy surgery is recruiting more patients to epilepsy surgery and providing critical information for surgical planning. MEG cortical mapping is helpful in younger pediatric patients, especially when the epileptogenic zone is close to the eloquent cortex. MEG is also used in both basic and clinical research of epilepsy other than surgery. MEG is a valuable diagnostic modality for diagnosis and treatment, as well as research in epilepsy.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.6
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• pp.461-467
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• 2009

The auditory cortex (A1) encodes the acquired significance of sound for the perception and interpretation of sound. Nitric oxide (NO) is a gas molecule with free radical properties that functions as a transmitter molecule and can alter neural activity without direct synaptic connections. We used whole-cell recordings under voltage clamp to investigate the effect of NO on spontaneous GABAergic synaptic transmission in mechanically isolated rat auditory cortical neurons preserving functional presynaptic nerve terminals. GABAergic spontaneous inhibitory postsynaptic currents (sIPSCs) in the A1 were completely blocked by bicuculline. The NO donor, S-nitroso-N-acetylpenicillamine (SNAP), reduced the GABAergic sIPSC frequency without affecting the mean current amplitude. The SNAP-induced inhibition of sIPSC frequency was mimicked by 8-bromoguanosine cyclic 3',5'-monophosphate, a membrane permeable cyclic-GMP analogue, and blocked by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, a specific NO scavenger. Blockade of presynaptic $K^+$ channels by 4-aminopyridine, a $K^+$ channel blocker, increased the frequencies of GABAergic sIPSCs, but did not affect the inhibitory effects of SNAP. However, blocking of presynaptic $Ca^{2+}$ channels by $Cd^{2+}$, a general voltage-dependent $Ca^{2+}$ channel blocker, decreased the frequencies of GABAergic sIPSCs, and blocked SNAP-induced reduction of sIPSC frequency. These findings suggest that NO inhibits spontaneous GABA release by activation of cGMP-dependent signaling and inhibition of presynaptic $Ca^{2+}$ channels in the presynaptic nerve terminals of A1 neurons.

• Journal of Korean Neurosurgical Society
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• v.50 no.3
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• pp.209-215
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• 2011

Objective : The authors investigated the changes of cortical sensorimotor activity in functional MRI (fMRI) and functional recovery in spinal cord injury (SCI) patients who had been treated by bone marrow cell transplantation. Methods : Nineteen patients with SCI were included in this study; ten patients with clinical improvement and nine without. The cortical sensorimotor activations were studied using the proprioceptive stimulation during the fMRI. Results : Diagnostic accuracy of fMRI with neurological improvement was 70.0% and 44.4% for sensitivity and specificity, respectively. Signal activation in the ipsilateral motor cortex in fMRI was commonly observed in the clinically neurological improved group (p-value=0.002). Signal activation in the contralateral temporal lobe and basal ganglia was more commonly found in the neurological unimproved group (p-value<0.001). Signal activation in other locations was not statistically different. Conclusion : In patients with SCI, activation patterns of fMRI between patients with neurologic recovery and those without varied. Such plasticity should be considered in evaluating SCI interventions based on behavioral and neurological measurements.

• Biomolecules & Therapeutics
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• v.18 no.1
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• pp.24-31
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• 2010

Taurine, 2-aminoethanesulfonic acid, is an abundant free amino acid present in brain cells and exerts many important biological functions such as anti-convulsant, modulation of neuronal excitability, regulation of learning and memory, anti-aggressiveness and anti-alcoholic effects. In the present study, we investigated to explore whether taurine has any protective actions against oxidative stress-induced damages in neuronal cells. ERK I/II regulates signaling pathways involved in nitric oxide (NO) and reactive oxygen species (ROS) production and plays a role in the regulation of cell growth, and apoptosis. We have found that taurine significantly inhibited AMPA induced cortical depolarization in the Grease Gap assays using rat cortical slices. Taurine also inhibited AMPA-induced neuronal cell damage in MTT assays in the differentiated SH-SY5Y cells. When the neuronal cells were treated with $H_2O_2$, levels of NO were increased; however, taurine pretreatment decreased the NO production induced by $H_2O_2$ to approximately normal levels. Interestingly, taurine treatment stimulated ERK I/II activity in the presence of AMPA or $H_2O_2$, suggesting the potential role of ERK I/II in the neuroprotection of taurine. Taken together, taurine has significant neuroprotective actions against AMPA or $H_2O_2$ induced damages in neuronal cells, possibly via activation of ERK I/II.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.2
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• pp.159-167
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• 2000

We have synthesized a novel platinum(II) coordination complex containing cis-1,2-diaminocyclohexane (DACH) as a carrier ligand and 1,2-dichloroethane (DCE) as a leaving group. In addition, nitrate was added to improve the water-solubility. A new series of [Pt(cis-DACH)(DCE)] $2NO_3(PC)$ was evaluated for its cytotoxic activity on T-24 and J-82 human bladder carcinoma cells and normal primary cultured kidney cells. PC has demonstrated high levels of cytotoxicity against T-24 and J-82 cells. The cytotoxicity of PC against rabbit proximal renal tubular cells, human renal cortical cells and human renal cortical tissues, determined using the MTT assaying technique, the $[^3H]-thymidine$ uptake and glucose consumption tests, was found to be quite less than those of cisplatin. Based on these results, this novel platinum(II) coordination complex appears to be better for improving antitumor activities with low nephrotoxicity and is a valuable lead in the development of new clinically available anticancer chemotherapeutic agents.

• Science of Emotion and Sensibility
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• v.6 no.1
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• pp.47-53
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• 2003

This study is an experimental study about the relationship between EEG and personality dimensions. Subjects were 70 healthy undergraduate students (32 males, 38 females) The Korean version of Eysencks Personality Questionnaire-Revised (EPQ-R) were used. EEGs were recorded in two different conditions (eyes open and eyes closed). To obtain more tellable data, EEG recordings of subjects were replicated 6 weeks later. The analytical methods used in the present study rendered two coincident tendencies: Theta with neuroticism relationship in eyes closed condition, and alpha-delta with psychoticism relationship in eyes closed condition. These results generally support the theory of Robinson (2001) that delta, theta, and alpha waves are associated with activity of brainstem, limbic system, and thalamo-cortical arousal system, and that thalamo-cortical alpha system has inhibitory effects on brainstem delta system.

• Molecules and Cells
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• v.38 no.4
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• pp.312-317
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• 2015

Depletion of intracellular zinc by N,N,N,N-tetrakis(2-pyridylmethyl) ethylenediamine (TPEN) induces p53-mediated protein synthesis-dependent apoptosis of mouse cortical neurons. Here, we examined the requirement for poly(ADP-ribose) polymerase (PARP)-1 as an upstream regulator of p53 in zinc depletion-induced neuronal apoptosis. First, we found that chemical inhibition or genetic deletion of PARP-1 markedly attenuated TPEN-induced apoptosis of cultured mouse cortical neurons. Poly(ADP-ribosyl)ation of p53 occurred starting 1 h after TPEN treatment. Suggesting the critical role of PARP-1, the TPEN-induced increase of stability and activity of p53 as well as poly(ADP-ribosyl)ation of p53 was almost completely blocked by PARP inhibition. Consistent with this, the induction of downstream pro-apoptotic proteins PUMA and NOXA was noticeably reduced by chemical inhibitors or genetic deletion of PARP-1. TPEN-induced cytochrome C release into the cytosol and caspase-3 activation were also blocked by inhibition of PARP-1. Taken together, these findings indicate that PARP-1 is essential for TPEN-induced neuronal apoptosis.

• Biomolecules & Therapeutics
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• v.8 no.3
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• pp.228-234
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• 2000

We have synthesized a novel platinum(II) coordination complex containing trans-ι-1,2-diaminocy-clohexane (DACH) as a carrier ligand and 1,2-dichloroethane (DCE) as a leaving group. A new series of [Pt(trans-ι-DACH)(DCE)](PC) was evaluated for its cytotoxic activity on MKN-45 human gastric adenocar-cinoma cells and normal primary cultured kidney cells. The new platinum complex has demonstrated high efficacy in the cytotoxicity against MKN-45/P, MKN-45/ADM and MKN-45/CDDP cell-lines. The cytotoxicity of PC against rabbit proximal renal tubular cells, human renal cortical cells and human renal cortical tissues, determined by MTT assay, the [$^3H$]-thymidine uptake arid glucose consumption tests, was found to be quite less than those of cisplatin. Based on these results, this novel platinum(II) coordination complex appears to be better for improving antitumor activities with low nephrotoxicity and is a valuable lead in the development of new, clinically available anticancer chemotherapeutic agents.

• Journal of Korean Neurosurgical Society
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• v.62 no.3
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• pp.272-287
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• 2019

The mechanistic target of rapamycin (mTOR) pathway coordinates the metabolic activity of eukaryotic cells through environmental signals, including nutrients, energy, growth factors, and oxygen. In the nervous system, the mTOR pathway regulates fundamental biological processes associated with neural development and neurodegeneration. Intriguingly, genes that constitute the mTOR pathway have been found to be germline and somatic mutation from patients with various epileptic disorders. Hyperactivation of the mTOR pathway due to said mutations has garnered increasing attention as culprits of these conditions : somatic mutations, in particular, in epileptic foci have recently been identified as a major genetic cause of intractable focal epilepsy, such as focal cortical dysplasia. Meanwhile, epilepsy models with aberrant activation of the mTOR pathway have helped elucidate the role of the mTOR pathway in epileptogenesis, and evidence from epilepsy models of human mutations recapitulating the features of epileptic patients has indicated that mTOR inhibitors may be of use in treating epilepsy associated with mutations in mTOR pathway genes. Here, we review recent advances in the molecular and genetic understanding of mTOR signaling in epileptic disorders. In particular, we focus on the development of and limitations to therapies targeting the mTOR pathway to treat epileptic seizures. We also discuss future perspectives on mTOR inhibition therapies and special diagnostic methods for intractable epilepsies caused by brain somatic mutations.