Biomedical subjects

J S Kwon

Publications and source records attributed to J S Kwon.

At least 19 recordsLinked to original sources

PubMed2006

Altered neural circuit for working memory before and after symptom provocation in patients with obsessive-compulsive disorder.

OBJECTIVE: The authors compared the neural circuits recruited for working memory (WM) in obsessive-compulsive disorder (OCD) patients both at a neutral state and at a symptom provoked state. METHOD: Twelve OCD patients, and 12 age-, and sex-matched healthy subjects underwent [(15)O]H(2)O positron emission tomography (PET) scanning, while performing WM task. In the patients, the tasks were performed both in the neutral and in the symptom provoked states. RESULTS: In the OCD patients, the right caudate and the right superior parietal cortex (rSPC) displayed activations for WM at the neutral state, while the right cingulate cortex and rSPC displayed activations for WM at the symptom provoked state. Path analysis revealed that the activity of the caudate and orbitofrontal cortex was altered according to the interaction between WM and symptom provocation. CONCLUSION: The interaction between symptom provocation and WM occurring in the fronto-striatal system may hold the key to the neurobiology of OCD.

Adult↗

PubMed2006

OK-432 sclerotherapy of plunging ranula in 21 patients: it can be a substitute for surgery.

BACKGROUND AND PURPOSE: Although first-choice therapy for the ranula is surgery, this choice presents technical difficulties and frequent recurrences because of insufficient surgery. We evaluated the efficacy of OK-432 sclerosis of the plunging ranula as a substitute for surgery. METHODS: Twenty-one patients with plunging ranula were treated with intralesional injection of OK-432. The liquid content of the ranula was aspirated as much as possible, after which OK-432 solution was injected in the same volumes as that drawn out. Patients were followed on sonography or CT. RESULTS: Seven (33.3%) patients with plunging ranulas showed total shrinkage and resolution, and 4 (19%) patients showed near-total shrinkage (more than 90% of the volume). Four (19%) patients revealed marked shrinkage (more than 70% of the volume), and 3 (14.3%) patients showed partial shrinkage (less than 70% of the volume). Three (14.3%) patients showed recurrence after total shrinkage 1 month after injection. The overall recurrence rate after each injection was 47% (16 of 34 injections in 21 patients), but the recurrence rate after the last sclerotherapy was only 14%. There were no serious side effects except for fever lasting 2-3 days (12 patients) and swelling (10 patients) for 3-5 days. Mild odynophagia for 1-2 days was also noted in 7 patients, and there was 1 severe case of odynophagia. CONCLUSION: OK-432 sclerotherapy of plunging ranula is a safe and potentially curative procedure that may be used as a primary treatment for plunging ranula before considering surgery.

Adolescent↗

PubMed2005

Decision-related factors and attitudes toward donation in living related liver transplantation: ten-year experience.

INTRODUCTION: Living related liver transplantation (LRLT) has been performed since 1994 in Korea; more than 600 donors have contributed to our successful LRLT program for 10 years. Although the decision to donate is difficult and the donors need a formal psychosocial assessment, no system has been available to us for the assessment. This survey was performed as a presurveillance for the development of a psychosocial assessment protocol. METHODS: A survey questionnaire included 31 questions on general and medical characteristics, factors, and processes related to the decision for donation. Donors of partial livers at least 6 months ago during the period from December 1994 to August 2003 and whose address could be confirmed by telephone were enrolled in the study. RESULTS: A questionnaire was sent by mail to 441 contactable donors of whom 209 (47.4%) responded. Male-to-female ratio was 2:1 and mean age was 32.8 years (range: 16 to 60 years). The number of spousal donors was 120 (57.4%) and 164 (78.5%) donors were employed at the time of donation. Protestants, Buddhists, and Catholics were 29.2%, 19.1%, and 14.8%, respectively. Parents were the most common recipients (33.0%), followed by siblings (17.2%), extended family members (17.2%), and children (15.8%); one hundred eighty nine (90.4%) donors had decided by themselves, the major reason for donation in 192 (91.9%) donors was "to save the lives of family members and relatives." The first person who suggested donation was the donor (64.1%), followed by family members (23.9%) or the attending physicians (8.6%). Although 70.8% of donors answered that they were not hesitant to donate at the time of decision, 44.5% were uneasy at the possibility of being unable to sustain a normal life after donation, at their lack of knowledge on organ donation, and about the pain and fear of surgery. Family members and relatives (53.3%), medical personnel (46.7%), and previous donors (35.4%) were the preferable counselors compared to transplantation institutions and clergymen. The large majority (80.8%) of donors would encourage others to donate. CONCLUSIONS: Although the decision to donate was made by the donors themselves in most cases and they appeared firm and determined about their decision, a significant number of donors felt uneasy about possible complications of organ donation and effects on their lives after donation. A precise and formal psychosocial assessment protocol is needed to support and secure their decision before and after donation.

Adolescent↗

PubMed2004

Deficits of organizational strategy and visual memory in obsessive-compulsive disorder.

This study was conducted to investigate the deficits of organizational strategy and visual memory in obsessive-compulsive disorder (OCD). Thirty OCD patients and 30 healthy controls aged 20-35 years participated. The Maudsley Obsessive-Compulsive Inventory, Beck Anxiety Inventory, Wechsler Adult Intelligence Scale, and Rey-Osterrieth Complex Figure (ROCF) test were administered to participants. The authors scored ROCF performances using the Boston Qualitative Scoring System. The OCD patients showed poorer planning ability and higher fragmentation than did healthy controls when copying the ROCF, and they showed even poorer performances in the immediate and delayed recall conditions. The authors found that the Organization score in the copy condition mediated the difference between the OCD group and the healthy group in immediate recall. The direct effect of diagnosis (OCD or healthy) on the immediate recall condition of the ROCF was also significant. This study indicates that people with OCD have poor memory function and organizational deficits.

Adult↗

PubMed2003

Non-linear registration for brain images by maximising feature and intensity similarities with a Bayesian framework.

The objective of this work was to provide a new, precise registration of the cortical mantle with a non-linear transformation. Image registration is broadly classified into two types, using intensity similarity and feature similarity. Whereas the former approach has merit in global brain matching, the latter provides a fast registration centred on a region of interest. The hybrid registration proposed in this paper was achieved using a Bayesian framework, which consisted of a likelihood model including intensity similarity and a prior model including feature information and a smoothing constraint. In this approach, each voxel was spatially transformed, so that the distance between corresponding features was shortened and also so that the intensity correlation was maximised. The result of the hybrid method clearly showed a good match of global brain (r = 0.930) by including intensity similarity. Moreover, this method compensated for the approximated sulcus of the feature-based method with intensity information, so that the geometric shape and thickness of the sulcus at the feature-defined region was likely to be registered. The accuracy in the feature-defined area was improved by 33.4% and 7.5% compared with feature-based and intensity-based methods, respectively.

Bayes Theorem↗

PubMed2003

Irradiation effects on embryotoxicity and oxidative properties of gossypol dissolved in methanol.

Gossypol dissolved in methanol (0.25 and 0.5 mg/ml) was gamma-irradiated at 0, 5, 10, and 20 kGy. The gossypol content was significantly reduced by irradiation in a dose-dependent manner. Ames test performed with nonirradiated and irradiated gossypol solutions was negative at the level of 0.1, 0.5, 1, 10, 50, and 100 microg gossypol/plate. At the gossypol concentration of 2.5 microg/ml, the blastocysts formation rate of mice embryo were decreased by a factor of two as compared with the control, but irradiation at 20 kGy increased the blastocysts formation, resulting in no difference from the control. Addition of gossypol to oil emulsion system or oil showed a prooxidative effect of lipids at the beginning stage by increasing 2-thiobarbituric acid reactive substances (TBARS) and peroxide value but irradiation of the gossypol solution decreased the oxidative changes significantly as compared with the nonirradiated one. Results indicated that irradiation decreased the gossypol concentration dissolved in methanol, resulting in a reduction of embryotoxicity in mice.

Animals↗

PubMed2003

Patterns of changes in temperament and character inventory scales in subjects with obsessive-compulsive disorder following a 4-month treatment.

OBJECTIVE: The purpose of this study was to assess changes in the temperament and character patterns in subjects with obsessive-compulsive disorder (OCD) following the treatment for obsessive/compulsive and accompanying depressive symptoms. METHOD: Study subjects were 35 patients who met the DSM-IV criteria for OCD. All subjects were assessed with the Temperament and Character Inventory (TCI), the Yale-Brown Obsessive-Compulsive Scale, the Beck Depression Inventory, and the Beck Anxiety Inventory before and after a 4-month treatment. RESULTS: Harm Avoidance (HA) scores in OCD subjects before treatment significantly decreased after treatment. However, the Self-Directedness scores, which were significantly lower than healthy comparison subjects before treatment, did not change. In addition, Reward Dependence scores in OCD subjects, which were not significantly different from healthy comparison subjects before treatment, significantly increased after treatment. CONCLUSION: The TCI pattern of untreated OCD subjects (high HA and low Self-Directedness, relative to healthy comparison subjects) and the decrease of HA scores and no change in Self-Directedness scores following a successful treatment suggest that temperaments are more amenable to treatment than characters.

Adolescent↗

PubMed2003

Brain glucose metabolic changes associated with neuropsychological improvements after 4 months of treatment in patients with obsessive-compulsive disorder.

OBJECTIVE: The study was designed to elucidate regional brain metabolic changes according to a treatment and their relationship with neuropsychological performance changes in obsessive-compulsive disorder (OCD). METHOD: Cerebral glucose metabolic rates were repeatedly measured before and after treatment in 10 patients with OCD using [18F]-2-fluoro-deoxyglucose positron emission tomography (PET). They were compared on a voxel-basis, and the correlations were counted between the regional metabolic changes and the degree to improvement on the neuropsychological assessments. RESULTS: After treatment, the patients showed significant (P < 0.005, two-tailed) regional metabolic changes in multiple brain areas involving frontal-subcortical circuits and parietal-cerebellar networks. Especially, the metabolic changes of the putamen, the cerebellum, and the hippocampus were significantly correlated with the improvement of the immediate- and delayed-recall scores of the Rey-Osterrieth Complex Figure Test (RCFT). CONCLUSION: These results suggest a possibility that metabolic changes of frontal-subcortical and parietal-cerebellar circuit changes may underlie cognitive improvements in patients with OCD.

Adult↗

PubMed2003

Similarity and disparity of obsessive-compulsive disorder and schizophrenia in MR volumetric abnormalities of the hippocampus-amygdala complex.

OBJECTIVES: Given that obsessive-compulsive disorder (OCD) and schizophrenia may share clinical symptoms as well as functional brain abnormalities, this study was designed to clarify common and different morphological abnormalities in OCD and schizophrenia. METHODS: Volumes of the hippocampus, the amygdala, and the thalamus were measured in three age and sex matched groups of 22 patients with OCD, 22 patients with schizophrenia, and 22 normal subjects using three dimensional magnetic resonance imaging. Volume tracing was performed manually on serial coronal slices with the references of sagittal or axial planes using internal landmarks. RESULTS: Hippocampal volume was bilaterally reduced in both OCD and schizophrenic patients versus the normal controls. Left amygdala volume was significantly enlarged in patients with OCD but not in patients with schizophrenia versus the normal controls. The thalamus did not show any volumetric group differences. CONCLUSIONS: Non-specific hippocampal reduction in both the OCD and schizophrenic groups is likely to link to a clinical overlap between the two illnesses, whereas the left amygdala enlargement observed only in the OCD patients seems to be suggestive of a unique role for the amygdala in the pathophysiology of OCD.

Adult↗

PubMed2001

Weekly intravenous methotrexate with folinic acid for nonmetastatic gestational trophoblastic neoplasia.

OBJECTIVE: The objective of this study was to determine the complete response rate to weekly intravenous methotrexate at 100 mg/m(2) with folinic acid for patients with nonmetastatic gestational trophoblastic neoplasia. METHODS: From 1988 to 1999, 22 women with nonmetastatic gestational trophoblastic neoplasia were treated with weekly intravenous methotrexate with folinic acid at the Hamilton Regional Cancer Centre. Complete response was defined as the attainment of a serum beta-hCG level <5 IU/L for 3 consecutive weeks. Toxicity was graded according to the National Cancer Institute of Canada-Clinical Trials Group criteria for chemotherapy toxicity. RESULTS: There were 10 women who achieved complete response with weekly intravenous methotrexate alone (45.5%). Of the 12 who did not achieve complete response with methotrexate, 10 received actinomycin D and 2 received EMA as second-line chemotherapy. Patients successfully treated with methotrexate required a median of 6.5 cycles (including 2 cycles for consolidation) to achieve complete response. The only significant prognostic factor for failure with methotrexate was pretreatment beta-hCG (P = 0.01). CONCLUSIONS: Only a select group of patients with low pretreatment beta-hCG titers would be expected to achieve complete response with this regimen. Large randomized studies are required to determine the optimal treatment for nonmetastatic gestational trophoblastic neoplasia.

Adult↗

PubMed2001

The effect of immediate and delayed word repetition on event-related potential in a continuous recognition task.

The dissociation of immediate and delayed word repetition was studied using a continuous recognition memory task and event-related potential (ERP). Among 240 stimulus words, 40 words were not repeated, 100 were immediately repeated and 100 were repeated after 5 intervening words. Words presented only once during the experiment were referred to as new words. Subjects responded faster and more accurately to words repeated immediately than to new words and to words repeated after a delay. In terms of ERP results, immediate repetition was associated with large P300 amplitude, early P300 latency and the absence of N400, while delayed repetition was associated with small P300 amplitude, late P300 latency and the presence of N400. N400 was elicited only to new words and to those repeated after intervening words. The general morphology of the waveforms was similar for two repetition conditions until around 310 ms after the onset of stimulus. These results indicate that distinct neural systems subserve the immediate and delayed repetition effect, and that the difference between the two emerges around 310 ms poststimulus. Immediate and delayed word repetition are considered in terms of template matching and memory searching, and are possibly mediated by the parietal and left medial temporal lobes, respectively.

Adult↗

PubMed2001

Frontal P300 decrement and executive dysfunction in adolescents with conduct problems.

This study investigated the cognitive and cerebral function of adolescents with conduct problems by neuropsychological battery (STIM) and event-related potential (ERP). Eighteen adolescents with conduct disorder, and 18 age-matched normal subjects were included. Such cognitive functions as attention, memory, executive function and problem solving were evaluated using subtests of STIM. ERP was measured using an auditory oddball paradigm. The conduct group showed a significantly lower hit rate on the Wisconsin Card Sorting Test (WCST) than the control group. In addition, the conduct group showed reduced P300 amplitude at Fz and Cz, and prolonged P300 latency at Fz, and there was a significant correlation between P300 amplitude and Stroop test performance. These results indicate that adolescents with conduct problems have impairments of executive function and inhibition, and that these impairments are associated with frontal dysfunction.

Adolescent↗

PubMed2001

A comparison of oral and vaginal misoprostol for induction of labour at term: a randomised trial.

OBJECTIVE: To compare the efficacy of oral with vaginal misoprostol for induction of labour at term. DESIGN: Randomised trial. SETTING: Tertiary Care hospital. PARTICIPANTS: One hundred and sixty-seven women requiring induction of labour. METHODS: The women were randomised to receive 50 microg of misoprostol orally or vaginally every 6 h until the cervix was favourable for amniotomy, spontaneous rupture of membranes, or active labour occurred. Sample size was calculated with a two-tailed alpha of 0.05 and a power of 95% to detect a 5 h difference in induction-to-delivery time. Student's t test was used for comparison of normally distributed continuous variables and the Mann-Whitney U test was used for non-Gaussian distributed continuous variables. Fisher' s exact and chi2 tests were used for comparison of categorical variables. The main outcome measure was induction to delivery time. RESULTS: The median induction to delivery time was significantly shorter with vaginal misoprostol (15.7 h range 4.3-55.7), compared with oral misoprostol (23.0 h range 3.2-141.7, P = 0.0013). The median number of doses was also significantly less in the vaginal misoprostol group, 1 (range 1-3), compared with the oral group, 2 (range 1-8), (P < 0.0001). The significant differences in outcome held true when nulliparous and multiparous women were analysed separately. There were no differences between the two routes of administration with respect to rates of hyperstimulation or neonatal asphyxia. There were more caesarean sections in the vaginal misoprostol group, but the difference was not statistically significant. CONCLUSIONS: Compared with oral misoprostol, vaginal misoprostol for induction of labour at term results in a shorter induction-to-delivery time, with fewer doses required per patient. Vaginal misoprostol may be associated with higher rates of caesarean section than oral misoprostol.

Administration, Intravaginal↗

PubMed2001

Grey matter abnormalities in obsessive-compulsive disorder: statistical parametric mapping of segmented magnetic resonance images.

BACKGROUND: Although a number of functional imaging studies are in agreement in suggesting orbitofrontal and subcortical hyperfunction in the pathophysiology of obsessive-compulsive disorder (OCD), the structural findings have been contradictory. AIMS: To investigate grey matter abnormalities in patients with OCD by employing a novel voxel-based analysis of magnetic resonance images. METHOD: Statistical parametric mapping was utilised to compare segmented grey matter images from 25 patients with OCD with those from 25 matched controls. RESULTS: Increased regional grey matter density was found in multiple cortical areas, including the left orbitofrontal cortex, and in subcortical areas, including the thalamus. On the other hand, regions of reduction were confined to posterior parts of the brain, such as the left cuneus and the left cerebellum. CONCLUSIONS: Increased grey matter density of frontal-subcortical circuits, consonant with the hypermetabolic findings from functional imaging studies, seems to exist in patients with OCD, and cerebellar dysfunction may be involved in the pathophysiology of OCD.

Adult↗

PubMed2001

Patterns of temperament and character in subjects with obsessive-compulsive disorder.

BACKGROUND: The purpose of this study was to assess the temperament and character patterns of obsessive-compulsive disorder (OCD) patients and to investigate the relationship between patterns of temperament and character and the severity of obsessive-compulsive symptoms. METHOD: The subjects were 40 patients who met DSM-IV criteria for OCD and 40 age-, sex-, and IQ-matched healthy controls. All subjects completed Cloninger's Temperament and Character Inventory. Other instruments included the Yale-Brown Obsessive Compulsive Scale, the Beck Depression Inventory, and the Beck Anxiety Inventory. RESULTS: OCD patients showed significantly higher scores of harm avoidance and lower scores of novelty seeking and self-directedness compared with healthy comparison subjects. In addition, the high harm avoidance and low self-directedness scores are correlated with a greater severity of obsessive-compulsive symptoms in OCD subjects (multiple regression analysis, beta = 0.39, t = 2.54, df = 34, p = .016; beta = -0.41, t = 2.46, df = 34, p = .019, respectively). CONCLUSION: OCD patients had distinct patterns of temperament and character compared with healthy comparison subjects. In addition, these patterns are specifically related to the severity of obsessive-compulsive symptoms.

Adult↗

PubMed2000

The CNS midline cells coordinate proper cell cycle progression and identity determination of the Drosophila ventral neuroectoderm.

The CNS midline cells, specified by the single-minded (sim) gene, are required for the proper patterning of the ventral CNS and epidermis, which are derived from the Drosophila ventral neuroectoderm. Defects in the sim mutant are characterized by the loss of the gene expression, which is required for the proper formation of the ventral neurons and epidermis, and by a decrease in the spacing of longitudinal and commissural axon tracks. Molecular and cellular mechanisms for these defects were analyzed to elucidate the precise role of the CNS midline cells in proper patterning of the ventral neuroectoderm during embryonic neurogenesis. These analyses showed that the ventral neuroectoderm in the sim mutant fails to carry out its proper formation and characteristic cell division cycle. This resulted in the loss of the dividing neuroectodermal cells that are located ventral to the CNS midline. The CNS midline cells are also required for the cell cycle-independent expression of the neural and epidermal markers. This indicates that the CNS midline cells are essential for the establishment and maintenance of the ventral epidermal and neuronal cell lineage by cell-cell interaction. On the other hand, the CNS midline cells do not cause extensive cell death in the ventral neuroectoderm. This study indicates that the CNS midline cells play important roles in the coordination of the proper cell cycle progression and the correct identity determination of the adjacent ventral neuroectoderm along the dorsoventral axis.

Animals↗

PubMed2000

Expression of brain/kidney protein in Müller cells of rat retina following transient ischemia.

We have investigated the expression and cellular localization of brain/kidney (B/K) protein in the rat retina following transient ischemia. In the normal retina, strong B/K immunoreactivity was localized to some ganglion cells. In addition, a few radial Muller cell processes showed B/K immunoreactivity. Following ischemia and reperfusion, most B/K-labeled ganglion cells were lost, whereas between 1 day and 2 weeks post-lesion B/K immunoreactivity appeared in many more Muller cell processes with increasing intensity. Quantitative evaluation by immunoblotting confirmed that B/K expression then decreased progressively, to 35% of control values at four weeks post-lesion. Our findings suggest that Muller cells are involved in the pathophysiology of retinal ischemia through the expression of B/K following transient ischemia.

Animals↗

PubMed2000

Planum temporale and Heschl gyrus volume reduction in schizophrenia: a magnetic resonance imaging study of first-episode patients.

BACKGROUND: Magnetic resonance imaging studies in schizophrenia have revealed abnormalities in temporal lobe structures, including the superior temporal gyrus. More specifically, abnormalities have been reported in the posterior superior temporal gyrus, which includes the Heschl gyrus and planum temporale, the latter being an important substrate for language. However, the specificity of the Heschl gyrus and planum temporale structural abnormalities to schizophrenia vs affective psychosis, and the possible confounding roles of chronic morbidity and neuroleptic treatment, remain unclear. METHODS: Magnetic resonance images were acquired using a 1.5-T magnet from 20 first-episode (at first hospitalization) patients with schizophrenia (mean age, 27.3 years), 24 first-episode patients with manic psychosis (mean age, 23.6 years), and 22 controls (mean age, 24.5 years). There was no significant difference in age for the 3 groups. All brain images were uniformly aligned and then reformatted and resampled to yield isotropic voxels. RESULTS: Gray matter volume of the left planum temporale differed among the 3 groups. The patients with schizophrenia had significantly smaller left planum temporale volume than controls (20.0%) and patients with mania (20.0%). Heschl gyrus gray matter volume (left and right) was also reduced in patients with schizophrenia compared with controls (13.1%) and patients with bipolar mania (16.8%). CONCLUSIONS: Compared with controls and patients with bipolar manic psychosis, patients with first-episode schizophrenia showed left planum temporale gray matter volume reduction and bilateral Heschl gyrus gray matter volume reduction. These findings are similar to those reported in patients with chronic schizophrenia and suggest that such abnormalities are present at first episode and are specific to schizophrenia.

Adolescent↗