Biomedical subjects

Yong-Wook Shin

Publications and source records attributed to Yong-Wook Shin.

At least 19 recordsLinked to original sources

PubMed2007

Neuropsychological profiles of patients with obsessive-compulsive disorder: early onset versus late onset.

In this study, we assess the neuropsychological profiles of both early and late symptom-onset obsessive-compulsive disorder (OCD) patients. The early and late-onset OCD patients are compared to the control group with a series of neuropsychological measurements. The late-onset OCD patients exhibited impaired performance on the immediate and the delayed recall conditions of the Rey-Osterrieth Complex Figure Test (RCFT) and the letter and category fluency of the Controlled Oral Word Association Test (COWA), compared to the normal controls and the early-onset OCD patients. The controls and early-onset OCD patients did not differ on any of the neuropsychological measurements taken in this study. These results suggest that different neurophysiological mechanisms are in play in early and late-onset OCD patients, and age of onset can serve as a potential marker for the subtyping of OCD.

Adult↗

PubMed2007

In vitro and in vivo antiallergic effect of the fructus of Evodia rutaecarpa and its constituents.

The unripe fruit of Evodia rutaecarpa (JUSS) BENTH (ER, Family Rutaceae) has been used frequently as a traditional medicine against inflammatory diseases in Korea, China and Japan. To evaluate antiallergic effect of ER, we isolated its main constituents, evodiamine and rutaecarpine, and evaluated in vivo their inhibitory effects against passive cutaneous anaphylaxis (PCA) reaction induced by IgE-antigen complex and scratching behaviors by compound 48/80. ER and its constituents, evodiamine and rutaecarpine, potently inhibited PCA reaction and scratching behaviors in mice, although ER weakly inhibited scratching behaviors. Evodiamine and rutaecarpine inhibited TNF-alpha and IL-4 protein expression in RBL-2H3 cells induced by IgE-antigen complex, although these did not inhibit degranulation of RBL-2H3 cells induced by IgE-antigen complex and rat peritoneal mast cells induced by compound 48/80. These findings suggest that ER and its constituents, evodiamine and rutaecarpine, may be effective for IgE-induced allergic diseases such as atopic dermatitis and rhinitis.

Alkaloids↗

PubMed2006

Pattern classification using principal components of cortical thickness and its discriminative pattern in schizophrenia.

We proposed pattern classification based on principal components of cortical thickness between schizophrenic patients and healthy controls, which was trained using a leave-one-out cross-validation. The cortical thickness was measured by calculating the Euclidean distance between linked vertices on the inner and outer cortical surfaces. Principal component analysis was applied to each lobe for practical computational issues and stability of principal components. And, discriminative patterns derived at every vertex in the original feature space with respect to support vector machine were analyzed with definitive findings of brain abnormalities in schizophrenia for establishing practical confidence. It was simulated with 50 randomly selected validation set for the generalization and the average accuracy of classification was reported. This study showed that some principal components might be more useful than others for classification, but not necessarily matching the ordering of the variance amounts they explained. In particular, 40-70 principal components rearranged by a simple two-sample t-test which ranked the effectiveness of features were used for the best mean accuracy of simulated classification (frontal: (left(%)|right(%))=91.07|88.80, parietal: 91.40|91.53, temporal: 93.60|91.47, occipital: 88.80|91.60). And, discriminative power appeared more spatially diffused bilaterally in the several regions, especially precentral, postcentral, superior frontal and temporal, cingulate and parahippocampal gyri. Since our results of discriminative patterns derived from classifier were consistent with a previous morphological analysis of schizophrenia, it can be said that the cortical thickness is a reliable feature for pattern classification and the potential benefits of such diagnostic tools are enhanced by our finding.

Adult↗

PubMed2006

Spatial accuracy of fMRI activation influenced by volume- and surface-based spatial smoothing techniques.

As improvements in cortical surface modeling allowed accurate cortical topology in brain imaging studies, surface-based methods for the analysis of functional magnetic resonance imaging (fMRI) were introduced to overcome the topological deficiency of commonly used volume-based methods. The difference between the two methods is mainly due to the smoothing techniques applied. For practical applications, the surface-based methods need to quantitatively validate the accuracy of localizing activation. In this study, we evaluated the spatial accuracy of activation detected by the volume- and surface-based methods using simulated blood oxygenation level-dependent (BOLD) signals and MRI phantoms focusing on the influence of their smoothing techniques. T1- and T2-weighted phantoms were acquired from BrainWeb () and used to extract cortical surfaces and to generate echo planar imaging (EPI) data. Simulated BOLD signals as the gold standard of activation in our experiment were applied to the surfaces and projected to the volume space with random noise. Three-dimensional isotropic Gaussian kernel smoothing and two-dimensional heat kernel smoothing were applied to the volume- and surface-based methods. Sensitivity and 1-specificity, which are truly and falsely detected activations, and similarity measures, which are spatially and statistically similar for the gold standard and detected activations, were calculated. In the results, the surface-based method showed the sensitivity and similarity scores of about 12% higher than the volume-based method. In conclusion, the surface-based method guarantees better spatial accuracy for the localization of BOLD signal sources within the cortex than the volume-based method.

Brain↗

PubMed2006

How does distortion correction correlate with anisotropic indices? A diffusion tensor imaging study.

PURPOSE: The purpose of this study was to determine a suitable registration algorithm for diffusion tensor imaging (DTI) using conventional preprocessing tools [statistical parametric mapping (SPM) and automated image registration (AIR)] and to investigate how anisotropic indices for clinical assessments are affected by these distortion corrections. MATERIALS AND METHODS: Brain DTI data from 15 normal healthy volunteers were used to evaluate four spatial registration schemes within subjects to correct image distortions: noncorrection, SPM-based affine registration, AIR-based affine registration and AIR-based nonlinear polynomial warping. The performance of each distortion correction was assessed using: (a) quantitative parameters: tensor-fitting error (Ef), mean dispersion index (MDI), mean fractional anisotropy (MFA) and mean variance (MV) within 11 regions of interest (ROI) defined from homogeneous fiber bundles; and (b) fiber tractography through the uncinate fasciculus and the corpus callosum. Fractional anisotropy (FA) and mean diffusivity (MD) were calculated to demonstrate the effects of distortion correction. Repeated-measures analysis of variance was used to investigate differences among the four registration paradigms. RESULTS: AIR-based nonlinear registration showed the best performance for reducing image distortions with respect to smaller Ef (P<.02), MDI (P<.01) and MV (P<.01) with larger MFA (P<.01). FA was decreased to correct distortions (P<.0001) whether the applied registration was linear or nonlinear and was lowest after nonlinear correction (P<.001). No significant differences were found in MD. CONCLUSION: In conventional DTI processing, anisotropic indices of FA can be misestimated by noncorrection or inappropriate distortion correction, which leads to an erroneous increase in FA. AIR-based nonlinear distortion correction would be required for a more accurate measurement of this diffusion parameter.

Adult↗

PubMed2006

An MRI study of structural variations in schizophrenia using deformation field morphometry.

Magnetic resonance imaging (MRI) has an important role in investigating the changes in brain structure that are associated with schizophrenia. In this study, MRI scans of patients diagnosed with schizophrenia (37 males; 19 females; 17-42 years of age) were compared with those of an age- and sex-matched group of normal subjects (37 males; 19 females; 18-40 years of age). Based on the images of the healthy control subjects, we constructed a representative average brain template. Automated image analysis techniques were used to measure differences in the regional nonlinear deformation fields between the two groups. A deformation field, which measures the spatial transformation to deform a template of brain anatomy to each individual data, was obtained as a three-dimensional displacement vector in each voxel. There was a significantly greater magnitude of the deformation fields in the superior frontal and parietal lobes as well as in the cingulate gyrus connecting both lobes of the patients with schizophrenia than in those of healthy controls, suggesting that these cerebral regions have a significantly higher structural variability in schizophrenia.

Adolescent↗

PubMed2006

Gender difference analysis of cortical thickness in healthy young adults with surface-based methods.

We have examined gender differences of cortical thickness using a 3-D surface-based method that enables more accurate measurement in deep sulci and localized regional mapping compared to volumetric analyses. Cortical thickness was measured using a direct method for calculating the distance between corresponding vertices from inner and outer cortical surfaces. We normalized cortical surfaces using 2-D surface registration and performed diffusion smoothing to reduce the variability of folding patterns and to increase the power of the statistical analysis. In stereotaxic space, significant localized cortical thickening in women was found extensively in frontal, parietal and occipital lobes, including the superior frontal gyrus (SFG), superior parietal gyrus (SPG), inferior frontal gyrus (IFG) and postcentral gyrus (PoCG) in the left hemisphere and mostly in the parietal lobe, including the SPG in the right hemisphere. In the temporal lobe, small regions of the left and right caudal superior temporal gyrus (STG) and the left temporal pole showed significantly greater cortical thickness in women. The temporal lobe shows relatively less significant thickening than other lobes in both hemispheres. In native space, significantly greater cortical thickness in women was detected in left parietal region, including SPG and PoCG. No significant local increases of cortical thickness were observed in men in both spaces. These findings suggest statistically significant cortical thickening in women in localized anatomical regions, which is consistent with several previous studies and may support a hypothesis of sexual dimorphism.

Adolescent↗

PubMed2006

Increased water diffusivity in the frontal and temporal cortices of schizophrenic patients.

Schizophrenia has been suggested to be the result of both macroscopic and microscopic abnormalities in the brain. Although no definitive clinico-pathological correlations have been found to reconcile the many facets inherent in this disorder, the recent development of the magnetic resonance diffusion tensor imaging (DTI) has allowed us to gather useful information regarding the microcircuitry of the brain. Specifically, the apparent diffusion coefficient (ADC) reflects the degree of diffusion barriers and heterosynaptic communication for the brain neurotransmitter. Nineteen patients with DSM-IV schizophrenia and 21 age- and sex-matched control subjects participated in DTI, and the severity of the patients' symptoms was evaluated according to the Positive and Negative Syndrome Scale (PANSS). The ADC values were determined and compared between patients and control subjects via voxel-based morphometry. The results show an increased ADC in the bilateral fronto-temporal regions of the schizophrenic patients, as compared with those of the control subjects. In addition, the ADC values in the area of the right insular were correlated with the negative syndromes from the PANSS. Our findings of increased water diffusivity in the fronto-temporal regions of schizophrenic patients and the correlation between negative symptom scales and the ADC in the right insular region indicate that damaged brain microcircuitry might contribute to the pathophysiology of schizophrenia. These findings contribute towards integrating micro and macrostructural abnormalities and syndromes of schizophrenia.

Adult↗

PubMed2006

Morphometric alterations of anterior superior temporal cortex in obsessive-compulsive disorder.

The superior temporal gyrus (STG) may be involved in the pathophysiology of obsessive-compulsive disorder (OCD). Moreover, the anterior STG has rich interconnections with the orbitofrontal cortex and the amygdala, and plays a role in visuospatial processing, which is impaired in patients with OCD. This study was designed to examine the morphological abnormalities of the anterior STG and their relationships with visuospatial function and clinical symptom in patients with OCD. We measured gray matter volumes of the anterior STG [rostral STG and planum polare (PP)] by three-dimensional (3D) magnetic resonance imaging in age- and sex-matched groups, which consisted of 22 patients with OCD and 22 normal volunteers. Visuospatial function and clinical symptom were assessed using the Rey-Osterrieth Complex Figure (ROCF) test, the Yale-Brown Obsessive Compulsive Scale, and the Maudsley Obsessive Compulsive Inventory. We found significant volume reductions in bilateral PPs, but there were no significant correlations between brain volumes and the ROCF copy score, immediate or delayed recall score, and clinical symptom in patients with OCD. These results suggest that volume reduction of the anterior STG, especially the PP, may be related to the pathophysiology of OCD, but further research may be needed to explore a relationship of the PP volume change with cognitive impairment observed in patients with OCD.

Adult↗

PubMed2006

Fractal dimension in human cortical surface: multiple regression analysis with cortical thickness, sulcal depth, and folding area.

Fractal dimension (FD) has been widely used to provide a quantitative description of structural complexity in the cerebral cortex. FD is an extremely compact measure of shape complexity, condensing all details into a single numeric value. We interpreted the variation of the FD in the cortical surface of normal controls through multiple regression analysis with cortical thickness, sulcal depth, and folding area related to cortical complexity. We used a cortical surface showing a reliable representation of folded gyri and manually parcellated it into frontal, parietal, temporal, and occipital regions for regional analysis. In both hemispheres the mean cortical thickness and folding area showed significant combination effects on cortical complexity and accounted for about 50% of its variance. The folding area was significant in accounting for the FD of the cortical surface, with positive coefficients in both hemispheres and several lobe regions, while sulcal depth was significant only in the left temporal region. The results may suggest that human cortex develops a complex structure through the thinning of cortical thickness and by increasing the frequency of folds and the convolution of gyral shape rather than by deepening sulcal regions. Through correlation analysis of FD with IQ and the number of years of education, the results showed that a complex shape of the cortical surface has a significant relationship with intelligence and education. Our findings may indicate the structural characteristics that are revealed in the cerebral cortex when the FD in human brain is increased, and provide important information about brain development.

Adult↗

PubMed2006

Effects of DRD2 and CYP2D6 genotypes on delta EEG power response to aripiprazole in healthy male volunteers: a preliminary study.

The aim of the present study was to evaluate the effects of polymorphisms in dopamine D2 receptor (DRD2) and cytochrome P450 (CYP) 2D6 genes on delta EEG power response to aripiprazole in healthy male volunteers. Seventeen volunteers were recruited according to the DRD2 Taq1A genotype, and separated into the following groups: homozygous wild-type (A2/A2, n = 7), heterozygous (A2/A1, n = 5) and homozygous variant-type (A1/A1, n = 5) groups. After enrollment in this study, they were genotyped for CYP2D6. The volunteers received single 10 mg oral doses of aripiprazole, in accordance with an open-label parallel group study design. Plasma levels of aripiprazole and its metabolite were determined and EEGs were obtained simultaneously. The pharmacodynamic parameter was absolute delta power in the Cz channel. The changes of delta power were not different according to DRD2 Taq1A genotypes. As to the CYP2D6 allele, the subjects had the following CYP2D6 genotypes: *10/*10 (n = 4), *1/*10 (n = 5), *1/*5 (n = 2), *1/*1 (n = 3), *2/*41 (n = 1), *2/*2 (n = 1), *2N/*10 (n = 1). Subjects exhibiting the *1/*5 and *1/*10 genotypes showed a trend toward high area under the plasma aripiprazole concentration-time curve (AUC), which was linearly related to area under the EEG response-time curve (AUEC). Our results demonstrate a need for further evaluation of the CYP2D6 genotypic effect on the pharmacodynamics of aripiprazole.

Adult↗

PubMed2006

Inhibitory effect of ginsenoside Rg5 and its metabolite ginsenoside Rh3 in an oxazolone-induced mouse chronic dermatitis model.

The effect of a main constituent ginsenoside Rg5 isolated from red ginseng and its metabolite ginsenoside Rh3 in a chronic dermatitis model was investigated. Ginsenosides Rg5 and Rh3 suppressed swelling of oxazolone-induced mouse ear contact dermatitis. These ginsenosides also reduced mRNA expressions of cyclooxygenase-2, interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma. The inhibition of ginsenoside Rh3 was more potent than that of ginsenoside Rg5. These findings suggest that ginsenoside Rh3 metabolized from ginsenoside Rg5 may improve chronic dermatitis or psoriasis by the regulation of IL-1beta and TNF-alpha produced by macrophage cells and of IFN-gamma produced by Th cells.

Animals↗

PubMed2006

Lactic acid bacteria increase antiallergic effect of Artemisia princeps pampanini SS-1.

Artemisia princeps Pampanini, which is called Ssajuarissuk in Korean (SS-1), was fermented with lactic acid bacteria (LAB) and their passive cutaneous anaphylaxis reaction-inhibitory activity was investigated. Of these fermented agents, SS-1 extract fermented with Bifidobacterium infantis K-525 (F-SS-1) most effectively inhibited the release of P-hexosamindase from RBL-2H3 cells induced IgE. In IgE-induced RBL-2H3 cells, F-SS-1 inhibited proinflammatory cytokines IL-6 and TNF-alpha mRNA expression. Oral administration of SS-1 and F-SS-1 to mice inhibited passive cutaneous anaphylaxis (PCA) reaction induced by IgE and scratching behaviors induced by compound 48/80. The inhibitory activity of F-SS-1 against scratching behaviors was more effective than that of SS-1. These findings suggest that the fermentation of SS-1 with LAB can increase its antiallergic activity.

Animals↗

PubMed2006

The effects of ginsenoside Re and its metabolite, ginsenoside Rh1, on 12-O-tetradecanoylphorbol 13-acetate- and oxazolone-induced mouse dermatitis models.

The effects of the main constituent ginsenoside Re in ginseng and its metabolite, ginsenoside Rh1, were investigated in 12-O-tetradecanoylphorbol 13-acetate (TPA)- and oxazolone-induced mouse ear dermatitis models. Ginsenoside Rh1 potently suppressed the TPA- and oxazolone-induced swellings as well as mRNA expression levels of cyclooxygenase-2, IL-1beta and TNF-alpha, although these were only weakly inhibited by ginsenoside Re.

Administration, Cutaneous↗

PubMed2006

Different brain activation patterns to pain and pain-related unpleasantness during the menstrual cycle.

BACKGROUND: The changes in the functional magnetic resonance imaging signal during anticipation, pain stimulation, and the poststimulation periods were investigated to determine whether changes in sex hormones affect brain activity. METHODS: Eighteen participants were examined twice, once in the follicular phase and once in the luteal phase. Half the participants were tested first during the follicular phase, and the other half were tested first in the luteal phase. RESULTS: The pain and unpleasantness ratings were significantly higher in the luteal phase than in the follicular. During the anticipation of pain, the prefrontal cortices were activated during the follicular phase, whereas the parahippocampal gyrus and amygdala were activated during the luteal phase. During the pain stimulation, putamen and cerebellum and precentral gyrus involving motor preparation and defense mechanism related to antinociceptive behavior were activated during the follicular phase, whereas the thalamus was activated during the luteal phase. During the poststimulation periods, the prefrontal cortices were activated during the follicular phase, whereas parahippocampal gyrus was activated during the luteal phase. The temporal pole was activated during the anticipation, pain stimulation, and poststimulation periods of the luteal phase. CONCLUSIONS: During surgical and medical procedures, requirements of anesthetic and analgesic and anxiolytic drugs may be reduced during the follicular phase and increased during the luteal phase. These results highlight the need to consider the effects of the sex hormones in women when designing clinical or neuroimaging studies or when treating patients for pain and pain-related unpleasantness.

Adult↗

PubMed2006

Effect of cognitive training focusing on organizational strategies in patients with obsessive-compulsive disorder.

The purpose of the present paper was to develop a cognitive training program for patients with obsessive-compulsive disorder (OCD) and evaluate its effectiveness. Nine 60-min sessions focusing on the improvement of organizational strategies were given to 15 patients with OCD over a period of 5 weeks. The control group consisted of 15 age- and sex-matched patients also with OCD. The Rey-Osterrieth Complex Figure Test and Korean-California Verbal Learning Test were administered before and after cognitive training. Clinical symptoms were assessed with the Yale-Brown Obsessive-Compulsive Scale. The memory function in the treatment group improved and their clinical symptoms were alleviated after training, compared to those of the control group. Cognitive training of OCD patients not only improved their memory function, but also alleviated their clinical symptoms. Therefore, cognitive training, focusing on the improvement of organizational strategies, could be an effective treatment modality for patients with OCD.

Activities of Daily Living↗

PubMed2006

Inhibitory effects of Korean red ginseng and its genuine constituents ginsenosides Rg3, Rf, and Rh2 in mouse passive cutaneous anaphylaxis reaction and contact dermatitis models.

The inhibitory effects of the Korean red ginseng (steamed root of Panax ginseng C.A. MEYER, family Araliaceae) saponin fraction (KRGS) and its constituents ginsenosides Rg3, Rf, and Rh2 in mouse passive cutaneous anaphylaxis (PCA) and contact dermatitis models were measured. Orally administered KRGS and its genuine ginsenosides potently inhibited the PCA reaction induced by IgE. However, when these ginsenosides were intraperitoneally administered, ginsenoside Rh2 showed the most potent inhibition. The ginsenoside Rh2 also the most potently inhibited the beta-hexosaminidase release from RBL-2H3 cells induced by IgE with antigen. KRGS administered topically at a dose of 0.1% suppressed ear swelling in an oxazolone-induced mouse contact dermatitis model by 38.8%. Its constituents ginsenosides Rg3, Rf, and Rh2 at a concentration of 0.05% also potently suppressed mouse ear swelling by 47.5%, 34.8%, and 49.9% at 16 d, respectively. These ginsenosides also significantly reduced mRNA expression levels of cyclooxygenase (COX)-2, interleukin (IL)-1beta, tumor necrosis factor-alpha and interferon-gamma induced by oxazolone applied to mouse ears. However, the ginsenosides, except for ginsenoside Rh2, almost did not notably reduce IL-4 levels. The ginsenoside Rh2 also potently inhibited COX-2 and inducible NO synthetase protein expression in liphopolysaccharide-stimulated RAW264.7 cells. Based on these findings, KRGS and its ginsenosides are suggested to improve atopic and contact dermatitis by regulating expression of cytokines.

Animals↗

PubMed2005

Self-initiated encoding facilitates object working memory in schizophrenia: implications for the etiology of working memory deficit.

BACKGROUND: Working memory (WM) deficit is present in a majority of patients with schizophrenia but it is unclear which components of WM are impaired. Past studies suggest that encoding may be compromised. One important determinant of encoding is the deployment of selective attention to the target stimulus. In addition, attention and encoding are modulated by motivational factors. In this study, we investigated the effects of self-initiated encoding (i.e., voluntary attention) on WM. METHODS: 19 patients with schizophrenia and 19 matched control subjects participated in visual WM and control tasks. Encoding was manipulated by asking subjects to select from two face targets and memorize 1) one of the two identical faces (Non-preference condition), 2) one that is marked (Non-choice condition), and 3) one they prefer (Preference condition). WM accuracy for both location (spatial) and identity (object) was measured. RESULTS: Overall, patients with schizophrenia were less accurate and slower than the control subjects but the deficit was greater for object WM. However, patients were more accurate in object WM when they selected a preferred face as their target during encoding (preference condition) compared with the other two conditions. This effect was not significant for spatial WM. CONCLUSIONS: These results suggest that voluntary, self-initiated attention may facilitate object encoding especially if the selection of the target involves affective choice, and that attention may play different roles in encoding 'what' versus 'where' in WM. Since encoding affects all forms of memory, these results may have a more general implication for memory.

Adult↗