Oh-Young Kwon

Hypoxic induction of caspase-11/caspase-1/interleukin-1β in brain microglia

Caspase-11 is an inducible protease that plays an important role in both inflammation and apoptosis. Inflammatory stimuli induce and activate caspase-11, which is required for the activation of caspase-1 or interleukin-1beta (IL-1beta) converting enzyme (ICE). Caspase-1 in turn mediates the maturation of proinflammatory cytokines such as IL-1beta, which is one of the crucial mediators of neurodegeneration in the central nervous system. Here, we report that hypoxic exposure of cultured brain microglia (BV-2 mouse microglia cells and rat primary microglial cultures) induces expression and activation of caspase-11, which is accompanied by activation of caspase-1 and secretion of mature IL-1beta and IL-18. Hypoxic induction of caspase-11 was observed in both mRNA and protein levels, and was mediated through p38 mitogen-activated protein kinase pathway. Transient global ischemia in rats also induced caspase-11 expression and IL-1beta production in hippocampus supporting our in vitro findings. Caspase-11-expressing cells in hippocampus were morphologically identified as microglia. Taken together, our results indicate that hypoxia induces a sequential event-caspase-11 induction, caspase-1 activation, and IL-1beta release-in brain microglia, and point out the importance of initial caspase-11 induction in hypoxia-induced inflammatory activation of microglia.

Frequency of affective symptoms and their psychosocial impact in Korean people with epilepsy: A survey at two tertiary care hospitals

We investigated the frequency of affective symptoms in Korean adults with epilepsy who visited epilepsy clinics at two tertiary care hospitals and in healthy adults. We also examined the psychosocial impact of affective symptoms on people with epilepsy (PWE). Participants were asked to complete self-report questionnaires to assess depression and anxiety symptoms, felt stigma, suicidal ideation, and quality of life (QOL). Of 568 PWE, 30.5% exhibited affective symptoms. The frequencies of depression and anxiety symptoms were 27.8% and 15.3%, respectively, significantly higher than those in healthy controls. Those with poor seizure control were more likely to endorse affective symptoms at the time of study. The frequencies of felt stigma and suicidal ideation were higher in PWE with affective symptoms than in those without. Quality of life was impacted by affective symptoms, especially when depression and anxiety coexisted. Reducing affective symptoms by appropriate seizure control may ameliorate psychosocial problems in PWE.

What is the role of depressive symptoms among other predictors of quality of life in people with well-controlled epilepsy on monotherapy?

The quality of life (QOL) of individuals with well-controlled epilepsy (WCE) is often not considered. We therefore investigated predictors determining QOL in patients who had been seizure free at least 1 year on stable antiepileptic drug (AED) monotherapy. They were asked to complete self-report health questionnaires, including the Beck Depression Inventory (BDI), Adverse Event Profile (AEP), and Quality of Life in Epilepsy Inventory-31 (QOLIE-31). We looked for predictors of QOLIE-31 scores among the various demographic, socioeconomic, and clinical factors and BDI, and AEP scores. Depression symptoms were manifested by 18.7% of patients. People with depression symptoms were more likely to report adverse events than those without depression symptoms. The strongest predictor of QOL was BDI score, followed by AEP total score, years of education, and income. BDI score had 3.37 times the effect of AEP total score. In conclusion, QOL of patients with WCE is determined mainly by depressive symptoms.

Source Localization of Triphasic Waves: Implications for the Pathophysiological Mechanism

To investigate the current source location from the electroencephalograms (EEGs) of 12 patients who showed typical triphasic waves attributable to various causes, using the combination of a dipole source model and a distributed source model. The triphasic waves were explained by a single main dipole in 10 of the 12 patients, and 2 patients had two dipoles responsible for the triphasic waves. All the main dipoles had a radial orientation with respect to the frontal pole. The current density of the triphasic waves was distributed mainly in the bilateral medial frontal regions along the cingulate cortices. These findings suggest that current sources located in the medial frontal area are crucial for generating triphasic waves. The source localization may be useful for elucidating the pathophysiologic mechanism of generalized non-epileptic EEG activities, such as triphasic waves.

Emergency carotid artery stenting in patients with acute ischemic stroke due to occlusion or stenosis of the proximal internal carotid artery: a single-center experience

Background The feasibility, safety and effectiveness of emergency carotid artery stenting (eCAS) in patients with acute ischemic stroke (AIS) due to proximal internal carotid artery (ICA) stenosis or occlusion are still controversial. In this study we analyzed our experience with eCAS in patients with AIS. Methods Twenty-two eCAS procedures for proximal ICA stenosis or occlusion were performed in 22 patients at our institution between January 2011 and November 2013. The mean time from stroke symptom onset to presentation was 204 min (range 50–630 min) and the mean initial score on the National Institutes of Health Stroke Scale (NIHSS) was 12.55 (range 5–23). Ten patients had total occlusion of the proximal ICA and the remaining 12 patients had near total occlusion or severe stenosis (mean degree 90.7%, range 80–100%). Eleven patients also had tandem occlusion on the more distal intracranial arteries. Results Successful stent insertion was achieved in all patients and additional thrombectomy using a Solitaire stent or Penumbra aspiration catheter achieved a Thrombolysis In Cerebral Infarction grade of more than 2a in all patients with distal tandem occlusion. Procedure-related complications occurred in one patient (cerebral hyperperfusion syndrome) who recovered successfully. The mean NIHSS score at discharge was 3.55 (range 0–18). The mean modified Rankin Scale score at 3 months was 1±1.67 (range 0–6). Conclusions eCAS in patients with AIS due to proximal ICA stenosis or occlusion appears to be a technically feasible and effective method for achieving good clinical outcomes.

Comparison of Solitaire thrombectomy and Penumbra suction thrombectomy in patients with acute ischemic stroke caused by basilar artery occlusion

Background and purpose Acute ischemic stroke (AIS) caused by basilar artery occlusion (BAO) is a very severe neurological disease with a high mortality rate and poor clinical outcomes. In this study, we compared our experience of mechanical thrombectomy using the Solitaire stent (Solitaire thrombectomy) and manual aspiration thrombectomy using the Penumbra reperfusion catheter (Penumbra suction thrombectomy) in patients with AIS caused by BAO. Materials and methods Between March 2011 and December 2011, 13 patients received Solitaire thrombectomy. In January 2012, the Korean Food and Drug Administration banned the use of the Solitaire stent as a thrombectomy device, and a further 18 patients received Penumbra suction thrombectomy until December 2013. We compared parameters between patients treated with each device. Results Successful recanalization rates (Thrombolysis in Cerebral Infarction (TICI) score ≥2b: 84.6% vs 100%, p=0.168) and clinical outcomes (judged by the modified Rankin Scale scores recorded at 3 months: 3.6±2.6 vs 3.2±2.6, p=0.726) were not significantly different between the two groups. However, complete recanalization rates (TICI score of 3: 23.1% vs 72.2%, p=0.015) and total procedure times (101.9±41.4 vs 62.3±34.8 min, p=0.044) were significantly higher, and shorter, respectively, in patients treated by Penumbra suction thrombectomy. Conclusions The two thrombectomy devices were associated with similar recanalization rates and clinical outcomes in patients with AIS caused by BAO. However, Penumbra suction thrombectomy seemed to allow more rapid and complete recanalization than Solitaire thrombectomy.

Carotid artery stenting in patients with near occlusion: a single-center experience and comparison with recent studies.

OBJECTIVE The optimal management strategy for carotid artery near occlusion is still controversial. Nevertheless, prior studies about carotid artery stenting in patients with near occlusion reported both technically and clinically inspiring results. To define the effectiveness, safety, and clinical outcomes of carotid artery stenting in patients with near occlusion, we analyzed our experiences and compared with recent studies. METHODS We performed 24 carotid artery stenting procedures in 24 patients with near occlusion between January 2010 and July 2012. The patient group comprised 20 men (83.3%) and four women (16.7%) with a mean age of 69.5 years (range, 53-85 years). Eighteen patients had prior stroke or transient ischemic attack (75%), and six patients were asymptomatic (25%). RESULTS Successful stent insertion was achieved in 23 of 24 patients (95.8%). Cerebral hyperperfusion syndrome and post-procedural vascular events occurred in four patients, and all of these developed within 24h after the procedure (17.4%; two: hyperperfusion syndrome, two: acute myocardial infarction). The mean follow-up period after carotid artery stenting was 16.7±9.2 months (range, 6-32 months). No stroke related to carotid artery stenting or significant restenosis of the inserted stent developed during the follow-up period. CONCLUSIONS Carotid artery stenting in patients with near occlusion seems to be a technically feasible and effective method to prevent stroke recurrence. But hyperperfusion syndrome and post-procedural vascular event rates may be high, as shown in this study.

Marital status of people with epilepsy in Korea

A multicentre face-to-face interview was conducted to identify factors contributing to the marital status of people with epilepsy (PWE) in Korea. The marriage rate of PWEs was only 80% and the divorce rate was more than double that in the general population. Among the single subjects, 34% replied that they were unmarried because of epilepsy, and 76% of divorced PWEs replied that epilepsy was the cause of the divorce. The factors affecting the single and divorced status in PWEs included gender, an earlier onset of seizure and seizure onset before marriage. Not informing the spouse of the disease before marriage for fear of discrimination was not related to disadvantage in marriage negotiation or to divorce. Social stigmatization of epilepsy continues and impacts on the marital status of PWEs in Korea. However, there is no correlation between the perceived and the enacted stigmas of epilepsy.

Changes of Cerebral Current Source by Audiovisual Erotic Stimuli in Premature Ejaculation Patients

INTRODUCTION Premature ejaculation (PE) is one of the most common forms of male sexual dysfunction. The mechanisms of PE remain poorly understood, despite its high prevalence. AIM To investigate the pathophysiology and causes of PE in the central nervous system, we tried to observe the changes in brain current source distribution by audiovisual induction of sexual arousal. METHODS Electroencephalograpies were recorded in patients with PE (45.0 +/- 10.3 years old, N = 18) and in controls (45.6 +/- 9.8 years old, N = 18) during four 10-minute segments of resting, watching a music video excerpt, resting, and watching an erotic video excerpt. Five artifact-free 5-second segments were used to obtain cross-spectral low-resolution brain electromagnetic tomography (LORETA) images. MAIN OUTCOME MEASURES Statistical nonparametric maps (SnPM) were obtained to detect the current density changes of six frequency bands between the erotic video session and the music video session in each group. Comparisons were also made between the two groups in the erotic video session. RESULTS In the SnPM of each spectrum in patients with PE, the current source density of the alpha band was significantly reduced in the right precentral gyrus, the right insula, and both superior parietal lobules (P < 0.01). Comparing the two groups in the erotic video session, the current densities of the beta-2 and -3 bands in the PE group were significantly decreased in the right parahippocampal gyrus and left middle temporal gyrus (P < 0.01). CONCLUSIONS Neuronal activity in the right precental gyrus, the right insula, both the superior parietal lobule, the right parahippocampal gyrus, and the left middle temporal gyrus may be decreased in PE patients upon sexual arousal. Further studies are needed to evaluate the meaning of decreased neuronal activities in PE patients.

Effect of a ketogenic diet on EEG: analysis of sample entropy.

Although ketogenic diet (KD) is an effective alternative therapy for controlling intractable seizures, the anticonvulsant mechanism still remains unclear. Sample entropy (SampEn) provides a generalized measure of regularity in time-series data. To investigate the potential anticonvulsive mechanism of a KD, we analyzed the SampEn of electroencephalography (EEG) data in patients with intractable pediatric epilepsy before and after treatment with a KD. Seventeen pediatric patients with epilepsy who were treated with KD were enrolled in present study. Patients were classified as good responder and poor responder according to therapeutic responsiveness on KD. Thirty segments of 30-s epochs were selected before and after KD from each patient which were subject to SampEn. The KD increased the SampEn in the whole patient population; the SampEn increased significantly in all electrodes in the good responders, but the change in SampEn varied according to the electrode in the poor responders. Before the KD, the good responders had significantly lower SampEn values than the poor responders, but after the KD, SampEn values were higher in the good responders than in the poor responders. KD may have an anticonvulsive effect by decreasing the regularity of the EEG dynamics.