Hyoung-Ihl Kim

A co-operative study : Clinical characteristics of 334 Korean patients with Moyamoya Disease Treated at Neurosurgical Institutes (1976-1994)

Summary A co-operative study was conducted to determine the clinical characteristics of patients with moyamoya disease who were diagnosed and treated at neurosurgical institutes in Korea before 1995. Twenty-six hospitals contributed 505 cases and among them, the clinical characteristics of 334 patients with definite moyamoya disease were evaluated. The number of patients began to increase from the late 1980s, and after that approximately 20 patients were treated each year. There were two age peaks: from six to 15 and from 31 to 40 years of age. Haemorrhagic manifestations occurred in approximately 43% of the patients. The major clinical manifestations were haemorrhage in adults (62.4%) and ischaemia in children (61.2%). Overall 54.5% of the patients experienced decreased consciousness levels, mainly due to intracranial haemorrhage or cerebral infarction. In the patients with ischemic manifestations, the adult patients were more likely to have cerebral infarction than the pediatric patients (80% vs. 39%) and the pediatric patients were more likely to have TIA (61% vs. 25%). Thirty eight percent of the patients underwent bypass surgery and 53% of these procedures were performed bilaterally. Treatment policies, including indications for bypass surgery and commonly used drugs, were somewhat different according to the institution. Overall favorable outcome was 73%, and the most significant factor affecting poor outcome was haemorrhagic manifestation. This article describes the characteristics of 334 patients with moyamoya disease, who were diagnosed and treated at neurosurgical institutes in Korea before 1995.

[18F]FDG PET signal is driven by astroglial glutamate transport

Contributions of glial cells to neuroenergetics have been the focus of extensive debate. Here we provide positron emission tomography evidence that activation of astrocytic glutamate transport via the excitatory amino acid transporter GLT-1 triggers widespread but graded glucose uptake in the rodent brain. Our results highlight the need for a reevaluation of the interpretation of [18F]FDG positron emission tomography data, whereby astrocytes would be recognized as contributing to the [18F]FDG signal.

Radiofrequency Neurotomy of Cervical Medial Branches for Chronic Cervicobrachialgia

Chronic neck and arm pain or cervicobrachialgia commonly occurs with the degeneration of cervical spine. Authors investigated the usefulness of radiofrequency (RF) neurotomies of cervical medial branches in patients with cervicobrachialgia and analyzed the factors which can influence the treatment outcome. Demographic data, types of pain distribution, responses of double controlled blocks, electrical stimulation parameters, numbers and levels of neurotomies, and surgical outcomes were evaluated after mean follow-up of 12 months. Pain distribution pattern was not significantly correlated with the results of diagnostic blocks. Average stimulation intensity was 0.45 V, ranging from 0.3 to 0.69, to elicit pain response in cervical medial branches. The most common involvement of nerve branches was C4 (89%), followed by C5 (82%), C6 (75%), and C7 (43%). Among total of 28 patients, nineteen (68%) reported successful outcome according to outcome criteria after 6 months of follow-up (p=0.001), and eight (42%) of 19 patients reported complete relief (100%) of pain. Four patients showed recurrence of pain between 6 and 12 months. It was therefore concluded that cervical medial branch neurotomy is considered useful therapeutic modality for the management of cervicobrachialgia in selected patients, particularly in degenerative zygapophyseal disorders.

Diagnostic Relevance of Pressure-Controlled Discography

Discogenic pain is a leading cause of chronic low back pain. The authors investigated the efficacy of pressure-controlled discography to determine its role in clinical decision-making for the management of patients with discogenic pain. Pressure-controlled discography was performed in 21 patients (51 discs) with pain-provocation, followed by post-discography computerized tomography scans. Pain response was classified as positive response and negative response, and measured with visual analog scale scores. Discographic findings were graded by the modified Dallas discogram scale. Elastance, pain provocation on intradiscal pressure, pressure and volume of initial pain response, and pain response intensity were statistically analyzed. Elastance showed significant differences between Grade 0 and Grade 4 & 5. Decreased elastance with positive pain response group was a good indicator to imply that disc degeneration presumably is a pain generator. Results of pain response were well correlated with intradiscal pressure but not with the amount of injected volume. Among 31 discs of Grade 4 and 5, 74% showed negative pain response and 26% showed positive response. It was concluded that pressure-controlled discography was useful to diagnose discogenic pain and excellent guide in decision-making for spinal operations.

Pathophysiologic characteristics of balloon cells in cortical dysplasia

ObjectsBalloon cells are histopathological hallmarks of cortical malformations, i.e., focal cortical dysplasia (FCD) of the Taylor type or the cortical tubers of tuberous sclerosis, and they are believed to be the epileptogenic substrate and cause therapeutic drug resistant epilepsy in man. This study was carried out to investigate the developmental histogenesis and epileptogenesis of balloon cells in FCD.Materials and methodsWe used an immunohistochemical approach to examine the expressions of primitive neuroepithelial cell antigens (CD34, nestin, and vimentin), ionotrophic glutamate receptor subunits (NR1, NR2A/B, GluR1, GluR2, GluR3, GluR4, and GluR5/6/7), and P-glycoprotein in balloon cells from FCD and normal cerebral cortex epileptogenic lesions.ConclusionBalloon cells presented in clusters or as scattered cells throughout FCD lesions involving the gray and white matter. We found the balloon cells to be classifiable into three subtypes based on glial fibrillary acidic protein (GFAP) and neurofilament protein (NF-L) immunohistochemistry, i.e., as neuronal, astrocytic, and uncommitted. Immunopositivity for nestin, CD34, and vimentin in balloon cells of FCD suggests that they may be derived from the abnormal development and differentiation of neural stem cells. Moreover, it appears that epileptogenesis in cortical dysplasia is partly caused by the upregulations of some glutamate receptor subunit proteins (NR1, NR2A/B, GluR1, and GluR3) in balloon cells and dysplastic neurons. We speculate that the presence of the drug resistance protein P-glycoprotein in balloon cells might explain medically refractory epilepsy in FCD.

A Rat Model of Photothrombotic Capsular Infarct with a Marked Motor Deficit: A Behavioral, Histologic, and microPET Study

We present a new method for inducing a circumscribed subcortical capsular infarct (SCI), which imposes a persistent motor impairment in rats. Photothrombotic destruction of the internal capsule (IC) was conducted in Sprague Dawley rats (male; n=38). The motor performance of all animals was assessed using forelimb placing, forelimb use asymmetry, and the single pellet reaching test. On the basis of the degree of motor recovery, rats were subdivided into either the poor recovery group (PRG) or the moderate recovery group (MRG). Imaging assessment of the impact of SCI on brain metabolism was performed using 2-deoxy-2-[18F]-fluoro-D-glucose ([18F]-FDG) microPET (positron emission tomography). Photothrombotic lesioning using low light energy selectively disrupted circumscribed capsular fibers. The MRG showed recovery of motor performance after 1 week, but the PRG showed a persistent motor impairment for >3 weeks. Damage to the posterior limb of the IC (PLIC) is more effective for producing a severe motor deficit. Analysis of PET data revealed decreased regional glucose metabolism in the ipsilesional motor and bilateral sensory cortex and increased metabolism in the contralesional motor cortex and bilateral hippocampus during the early recovery period after SCI. Behavioral, histologic, and functional imaging findings support the usefulness of this novel SCI rat model for investigating motor recovery.

Effect of prolonged cortical stimulation differs with size of infarct after sensorimotor cortical lesions in rats.

Motor deficit improvement is limited in rats with a large sensorimotor cortex infarct, even with cortical stimulation during rehabilitation. However, we find prolonged stimulation that differs with the size of cortical lesion to be effective. Two weeks of prolonged epidural electrical stimulation and rehabilitative training were delivered to rats whose cortex had been subjected to photothrombotic infarct after training in a single-pellet reaching task. Continuous stimulation greatly improved recovery in animals with large infarcts (6 mm diameter), while intermittent stimulation was more effective in animals with small (4 mm) lesions. Thus, prolonged cortical stimulation is a strategy to enhance motor recovery in photothrombotic infarct model rats. However, pattern and duration of stimulation requires modification depending on the extent of infarct.

Factors influencing manometric pressure during pressure-controlled discography.

Study Design. In vitro laboratory study. Objective. The aim of this study was to evaluate the effects of injection speed, contrast viscosity, and needle profile on manometric pressures during discography. Summary of Background Data. As the degree of the response in a provocation test depends on the intensity of the stimulus, the precise measurement of intradiscal pressure during discography is crucial. Although manometric pressure measurement is safe and easy, manometric pressures may be affected by potential confounding factors, including injection speed, contrast viscosity, and needle profile. Methods. Pressure-controlled discography was performed using an automated pressure-controlled discography system in a total of 60 intervertebral discs in 2 porcine cadavers. Dynamic pressures were measured while changing the following parameters: injection speed (0.01 mL/s vs. 0.08 mL/s), media viscosity (Visipaque vs. normal saline), needle diameter (18G vs. 22G), and needle length (7 inch vs. 3.5 inch). The unit change in manometric pressure per fractional change in injected volume (dP/dV) was used for statistical analysis. Results. The mean dP/dV increased from 137.9 ± 11.3 at 0.08 mL/s to 160.3 ± 12.5 at 0.01 mL/s. Visipaque injection resulted in a higher mean dP/dV than the normal saline injection (160.3 ± 12.5 vs. 97.8 ± 34.1). A 7.5 inch needle had a higher mean dP/dV than a 3.5 inch needle (137.9 ± 11.3 vs. 92.5 ± 48.6). The mean dP/dV of the 22G needle was higher than the 18G needle (137.9 ± 11.3 vs. 84.7 ± 28.3). Conclusion. High injection speed, high viscosity, small diameter, and a long needle increase the dynamic pressure. To minimize the differences among examiners, we recommend standardization of injection speed, the viscosity of the injected material, and the diameter and length of the needle.

Differentiation Between Normal and Cancerous Cells at the Single Cell Level Using 3-D Electrode Electrical Impedance Spectroscopy

A novel microdevice for electrical impedance spectroscopy is presented to differentiate between normal and cancerous cells at the single cell level with a high sensitivity. The device utilizes a microfluidic tunnel structure, whose height is smaller than the cell diameters, to squeeze the target cells. Thus, the tight contact between the cells and electrodes allows the device to measure the intrinsic electrical properties of the cells with a higher sensitivity than through noncontact methods. Three-dimensional interdigitated electrodes (3-D IDE) are also employed to confine most of the electric field into the cell membrane, which contains the meaningful electrical properties. Consequently, the variance of the measured values could be reduced because the position of target cells is almost the same in every cell assay. The device well distinguishes normal human breast cells (MCF-10A) from early-stage human breast cancer cells (MCF-7) by means of electrical impedances at 500 kHz; the average differences of the real part and phase angle between the target cells are 44.4 and 1.41 , respectively. The proposed device also shows a high repeatability for the deionized (DI) water test conducted before and after each cell assay; the variances of the real part and phase angle of electrical impedance at 500 kHz are as small as 9.07 and 0.27 , respectively.

A case of angiocentric glioma with unusual clinical and radiological features.

Angiocentric glioma was recently recognized as a distinct clinicopathological entity in the 2007 World Health Organization classification of tumors of the central nervous system. Typically, it presents with seizure in children and young adults. However, our patient did not have a history of seizure. Seizure did not occur up to 6 months after operation. Although it usually does not have calcification brain magnetic resonance imaging in our patient showed T1-hyperintense and T2-hypointense signals with calcification.