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Yong-Wook Shin

Publications and source records attributed to Yong-Wook Shin.

33 records · Page 2Linked to original sources
PubMed2005

Representative brain selection using a group-specific tissue probability map.

PURPOSE: To determine the anatomy of a standard brain reflecting well-defined group characteristics based on probabilistic information from group-specific anatomical variations. MATERIALS AND METHODS: We constructed a group-specific tissue probabilistic map for 20 subjects and used it to extract voxel-wise probabilistic information for each subject through regional spatial normalization using Automated Image Registration software (AIR 5.2.5). Extracted probabilistic information was then used to determine standard properties of the subjects. For comparison, we employed an empirical scoring function - a measure of entropy - in ordering the data set. A brain with minimum entropy was then selected for a group standard. The evaluation of our proposed method was performed using two different selection schemes: deformation analysis and similarity index measurements. RESULTS: This method showed highly correlated result with previous method by Kochunov et al., with fewer computational tasks. CONCLUSION: This method can thus be used to determine an appropriate standard model to compare with disease-affected brains.

Adult↗
PubMed2005

Antipruritic effect of ginsenoside rb1 and compound k in scratching behavior mouse models.

The antipruritic and vascular permeability-inhibitory effects of ginsenoside Rb1, a main component of ginseng frequently used as a traditional medicine in Asian countries, and its metabolite compound K by intestinal microflora were investigated in scratching behavior animal models induced by compound 48/80, substance P, and histamine. Ginsenoside Rb1 and compound K orally administered 1 and 6 h before the treatment of compound 48/80 showed antipruritic effect. These ginsenosides administered at a dose of 50 mg/kg 6 h before the treatment of compound 48/80 inhibited scratching behaviors by 51% and 64%, respectively, compared with that of the control. These ginsenosides also inhibited the vascular permeability of skin. Compound K intraperitoneally administered 1 h before the treatment of compound 48/80 potently inhibited the scratching behaviors induced by compound 48/80. However, intraperitoneally administered ginsenoside Rb1 did not inhibit scratching behaviors. Compound K inhibited compound 48/80-, substance P-, and histamine-induced scratching behaviors, with 50% inhibitory doses of 4.2, 5.9, and 3.8 mg/kg, respectively, and vascular permeability, with 50% inhibitory doses of 5.8, 6.8, and 4.1 mg/kg, respectively. These results suggest that ginsenoside Rb1 and its metabolite compound K by intestinal microflora can improve scratching behaviors.

Animals↗
PubMed2005

Sex differences in the human corpus callosum: diffusion tensor imaging study.

In order to assess underlying structural differences between the male and female corpus callosum, the fractional anisotropy and volume of the corpus callosum, and also its T1 signal intensity, were measured. The corpus callosum of the 15 normal women and 15 normal men was drawn on the mid-sagittal T1-weighted image, for determining its volume and signal intensity, and this region of interest was projected onto the coregistered fractional anisotropy image, in order to obtain the value for the corpus callosum. We found increased T1 signal intensity and decreased fractional anisotropy in the female corpus callosum, as compared with that of the male. Despite the long-standing debates, the corpus callosum remains a region of sex differences.

Adult↗
PubMed2005

Quantitative analysis of group-specific brain tissue probability map for schizophrenic patients.

We developed group-specific tissue probability map (TPM) for gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF) on the common spatial coordinates of an averaged brain atlas derived from normal controls (NC) and from schizophrenic patients (SZ). To identify differences in group-specific TPMs, we used quantitative evaluation methods based on differences in probabilistic distribution as a global criterion, and the mean probability and the similarity index (SI) by lobe as regional criteria. The SZ group showed more spatial variation with a lower mean probability than NC subjects. And, for the right temporal and left parietal lobes, the SI between each group was lower than the other lobes. It can be said that there were significant differences in spatial distribution between controls and schizophrenic patients at those areas. In case of female group, although group differences in the volumes of GM and WM were not significant, global difference in the probabilistic distribution of GM was more prominent and the SI was lower and its descent rate was greater in all lobes, compared with the male group. If these morphological differences caused by disease or group-specific features were not considered in TPM, the accuracy and certainty of specific group studies would be greatly reduced. Therefore, suitable TPM is required as a common framework for functional neuroimaging studies and an a priori knowledge of tissue classification.

Adult↗
PubMed2005

Effect of ginsenoside Rb1 and compound K in chronic oxazolone-induced mouse dermatitis.

During the screening program to discover antipsoriatic agents from natural products, ginseng was found to show inhibitory activity in oxazolone-induced mouse ear dermatitis. Therefore, the effects of a main constituent ginsenoside Rb1 isolated from ginseng and its metabolite compound K on oxazolone-induced mouse ear dermatitis were investigated. Compound K at concentrations of 0.02% and 0.05% also potently suppressed mouse ear swelling by 54% and 76% at 16 days, respectively, although ginsenoside Rb1 did not significantly show the inhibitory activity. The compound K also significantly reduced the levels of mRNA of cyclooxygenase (COX)-2, IL-1beta, TNF-alpha, IFN-gamma and IL-4 increased in oxazolone-applied mouse ears. Based on these findings, the compound K may improve contact dermatitis or psoriasis by the regulation of COX-2 produced by macrophage cells and interferon-gamma and IL-4 induced by Th cells.

Animals↗
PubMed2005

Polarization dependence of the coupling ratio in LiTaO3 directional couplers.

The effect of design and fabrication parameters on the polarization dependence of the splitting ratio in directional couplers produced in LiTaO3 by Zn diffusion has been investigated experimentally at a wavelength of 1558 nm. The directional couplers featured various combinations of waveguide width, separation gaps between waveguides, bending angle, and diffusion conditions. In each case the coupling region was 3.5 mm long. Of particular interest was the identification of parameter sets for which the sum of power splitting ratios from TE and TM inputs equals unity at the output, as needed for electro-optic tunable filters with relaxed beam-splitter requirements.

Journal Article↗
PubMed2005

Asymmetry analysis of deformable hippocampal model using the principal component in schizophrenia.

The hippocampus is thought to play an important role in learning and memory processing, and impairments in memory, attention, and decision making are found commonly in schizophrenia. Although many studies have reported decreases in hippocampal volume in the left hemisphere in schizophrenia, regionally specific hippocampal volume loss has not been revealed consistently using volume analysis. Recently, many studies have analyzed shape asymmetry using 3-D models; however, inconsistent results have been reported, mainly due to methodologic differences. We therefore used an active, flexible, deformable shape model for surface parameterization, and compared shape asymmetry based on principal component analysis (PCA) in the hippocampi of schizophrenic patients with those of the normal controls. Although the overall pattern of the statistical results did not change according to the number of principal components, the reconstructed results based on six major components were much more distinguishable. Although the left hemispheric hippocampal volume was larger than the right hemispheric was in this study, the difference was not significant. In shape asymmetry analysis, the right hemisphere hippocampus was bilaterally larger than the left hemisphere hippocampus was in the head of the superior CA1 and smaller in the tail and head of the inferior CA1. The asymmetry in the schizophrenia group was statistically smaller than that in the control group through reduction of the left hemisphere hippocampus volume.

Adult↗
PubMed2005

The influence of complexes on implicit learning.

A century ago, Jung looked into the unconscious through complexes by using word association tests. Jung wrote, 'modern psychology with its investigation of complexes has opened up a psychic taboo area riddled with hopes and fears', and complexes remain an unexplored taboo area of research. In the present study, we have investigated the influence of complexes on unconscious cognitive processing, in particular on implicit learning. We have found that complexes shown to disturb conscious cognitive processing in fact enhanced the attention of the subjects and their performance on an implicit learning task. These results suggest that complexes are not just abstractions, but have various actual influences on both conscious and unconscious processing.

Adolescent↗
PubMed2005

Persistent cognitive dysfunction in patients with obsessive-compulsive disorder: a naturalistic study.

The purpose of the present study was to investigate the changes in the cognitive dysfunctions of patients with obsessive-compulsive disorder (OCD) over a 1-year period of pharmacological treatment. Twenty-one OCD patients and 20 normal subjects underwent neuropsychological tests and clinical evaluations on three separate occasions (baseline, 4 months, and 1 year after the start of medications). OCD patients continued to show significant impairments in the following cognitive measures compared with the normal controls: accuracy of immediate and delayed recall on the Rey-Osterrieth complex figure tests, the numbers of responses on the category fluency test, the response time on the trail making test--part A, and the number of perseverative response and perseverative errors on the Wisconsin card sorting test. The findings in this study suggested that impaired performance on cognitive domains, such as visuospatial memory and verbal fluency may underline the pathology of OCD.

Adult↗
PubMed2005

Effect of chunghyuldan in chronic oxazolone-induced mouse dermatitis.

To evaluate the antipsoriatic effect of Chunghyuldan (CHD, Daio-Orengedokuto in Japanese), which exhibited anti-inflammatory and antiischemic actions, the inhibitory activity of CHD metabolized with and without human intestinal microflora was investigated in oxazolone-induced mouse ear dermatitis. The CHD and metabolized CHD (MCHD) at concentrations of 0.1% also potently suppressed mouse ear swelling by 52.7% and 63.2% at 16 d, respectively. The antipsoriatic effect between CHD and MCHD was not significantly different, although that of CHD weakly increased by the metabolism of human intestinal microflora. Both CHD and MCHD also potently reduced the mRNA levels of cyclooxygenase (COX)-2, interferon (IFN)-gamma and IL-4 increased in oxazolone-applied mouse ears, but weakly inhibited that of IL-1beta and TNF-alpha. Based on these findings, CHD may improve contact dermatitis or psoriasis by the regulation of COX-2 produced by macrophage cells and IFN-gamma and IL-4 produced by Th cells.

Animals↗
PubMed2005

Inhibitory effect of ginsenoside Rb1 and compound K on NO and prostaglandin E2 biosyntheses of RAW264.7 cells induced by lipopolysaccharide.

In this study, the antiinflammatory activities of ginsenoside Rb1, which is a main constituent of the root of Panax ginseng (Araliaceae), and of its metabolite compound K, as produced by human intestinal bacteria, on lipopolysaccharide (LPS)-induced RAW264.7 cells were investigated. Compound K potently inhibited the production of NO and prostaglandin E2 in LPS-induced RAW 264.7 cells, with IC(50) values of 0.012 and 0.004 mM, respectively. Compound K also reduced the expression levels of the inducible NO synthase (iNOS) and COX-2 proteins and inhibited the activation of NF-kB, a nuclear transcription factor. Compound K inhibited the NO level produced by iNOS enzyme activity in a cell-free system, but did not inhibit COX-1 and 2 activities. When ginsenoside Rb1 was orally administered to rats, compound K, but not ginsenoside Rb1, were excreted in their urine. These findings suggest that ginsenoside Rb1 can be transformed to compound K by intestinal bacteria, and compound K may be effective against inflammation.

Animals↗
PubMed2005

Risperidone dosing pattern and clinical outcome in psychosis: an analysis of 1713 cases.

BACKGROUND: In treating patients with psychosis, practicing clinicians use various dosing strategies of antipsychotic medications, including risperidone. To evaluate the outcome of different risperidone dosing strategies in clinical practice, we undertook a large, prospective, naturalistic study in which daily dosage was determined freely by local standards of care. METHOD: In a 6-week trial between December 2000 and January 2002, 1713 patients with DSM-IV schizophrenia and related psychoses were treated with risperidone, with the dose, daily changes in dose, and weekly changes in Brief Psychiatric Rating Scale score documented. Cluster analysis was performed to identify homogeneous dosing patterns among the heterogeneous total population. RESULTS: Of the 6 dosing patterns identified by cluster analysis, a 2-week titration cluster, with a starting dose of 1.8 mg/day titrated to a maximum dose of 4.7 mg/day at day 14, and a 1-week titration cluster, with a starting dose of 2.6 mg/day titrated to a maximum dose of 5.4 mg/day at day 7, showed superior clinical outcomes compared with the other clusters, in which titrations were slower and higher. CONCLUSION: Our results indicate that the current consensus regarding risperidone dosing is appropriate for clinical practice, whereas a slower titration schedule does not guarantee a better clinical outcome, thus emphasizing the need for appropriate early titration.

Adult↗
PubMed2004

Association between EEG alpha power and visuospatial function in obsessive-compulsive disorder.

The purpose of the present paper was to determine if frontal activity, measured as electroencephalogram alpha power, correlates with visuospatial functions in obsessive-compulsive disorder (OCD). Electroencephalography and the Rey-Osterrieth Complex Figure Test (RCFT) were performed on 23 patients meeting the Diagnostic and Statistical Manual of Mental Disorders (4th edn; DSM-IV) OCD criteria. After quantitatively analyzing EEG recordings taken over the frontal, temporal, parietal and occipital regions (F1, F2, T3, T4, P3, P4, O1 and O2), the log transformed absolute power values of the alpha frequencies of the regions were regressed with each RCFT index (copy, immediate recall and delayed recall score). On the frontal region (F1, F2), the RCFT copy score was found to be correlated with the alpha power with regression coefficients that had different directions according to hemisphere (F1, 5.62; F2, -5.26). The result that visuo-constructional ability represented by the RCFT copy score correlated with frontal activation as measured by decreased alpha power, supports the opinion that visuospatial dysfunction in OCD is not in the visuospatial memory per se but rather that it is mediated by executive function deficit. The opposite correlation directions indicate that greater left frontal activation correlates with a poorer RCFT copy score and that greater right frontal activation correlates with a better copy score. These relationships provide indirect evidence of the possibility that the main pathology of OCD is located in the left hyperfrontality and that the right hyperfrontality of OCD occurs by a compensatory mechanism.

Adult↗
PubMed2004

Passive cutaneous anaphylaxis-inhibitory action of tectorigenin, a metabolite of tectoridin by intestinal microflora.

Tectoridin isolated from the flowers of Pueraria thunbergiana (Leguminosae) are metabolized to tectorigenin by human intestinal microflora. When tectoridin was orally administered to rats, tectorigenin, but not tectoridin, was detected in urine after beta-glucuronidase hydrolysis. The main metabolite tectorigenin potently inhibited the passive cutaneous anaphylaxis reaction and inhibited in vitro the release of beta-hexosaminidase from RBL-2H3 cells induced by IgE. These results suggest that tectoridin is a prodrug, which can be transformed into the active agent tectorigenin by human intestinal bacteria and can be a candidate for antiallergic agent.

Animals↗