Biomedical subjects

Seung Mo Sung

Publications and source records attributed to Seung Mo Sung.

3 recordsLinked to original sources

PubMed2003

Reduced cortical gray matter density in human MDMA (Ecstasy) users: a voxel-based morphometry study.

The popular recreational drug, 3,4-methylenedioxymethamphetamine (MDMA) exerts its actions in part via blockade of serotonin and dopamine reuptake. Many animal and human studies have demonstrated long-lasting reductions in measures of central nervous system (CNS) serotonin function following MDMA administration. One emerging role of serotonin function in the CNS is a positive trophic effect via stimulation of intracellular signaling pathways and trophic factors. We hypothesized that human MDMA users might display neocortical gray matter reductions due to loss of serotonergically mediated trophic effects on cortical cells. However, unlike animal models, most human MDMA users worldwide are polydrug users, thereby complicating the assessment of MDMA toxicity in this group. Structural magnetic resonance imaging (MRI) scans of 31 MDMA polydrug users versus 29 non-MDMA users were compared using voxel-based morphometry (VBM) to assess regional brain gray and white matter concentration. VBM employs gray/white matter segmentation and statistical parametric mapping (SPM) analysis to calculate a voxel-wise comparison of regional gray or white matter concentration. Using this method, we consistently found several brain regions having decreased gray matter concentration in MDMA polydrug users. These regions were localized to neocortex in bilateral Brodmann area (BA) 18, left BA 21, and left BA 45, as well as bilateral cerebellum, and midline brainstem. Overall, these preliminary findings suggest that MDMA polydrug users have multiple regions of gray matter reduction, potentially accounting for previously reported neuropsychiatric impairments in MDMA users. Additional animal model and human studies of the CNS effects of MDMA and combined MDMA-polydrug toxicity are needed to further explain these findings. Potential explanations for our results including pre-existing brain differences predisposing to MDMA polydrug use, direct MDMA and polydrug toxicity, indirect changes due to MDMA and polydrug toxicity, or combinations of all these factors.

Adolescent↗

PubMed2003

Multinuclear magnetic resonance spectroscopy of high-energy phosphate metabolites in human brain following oral supplementation of creatine-monohydrate.

Alterations in brain high-energy phosphate metabolism, determined by in vivo magnetic resonance spectroscopy (MRS), have been reported in subjects with a number of brain disorders including major depression, schizophrenia, and substance abuse. It is not clear to what extent these changes can be modified by pharmacological or nutritional means. To address this possibility, we evaluated changes in brain chemistry that were associated with oral creatine (Cr) administration. We hypothesized that oral Cr supplementation, by increasing brain creatine and high-energy phosphate stored in phosphocreatine, would result in an increase in the creatine resonance, as measured using proton 1H-MRS, and a decrease in the beta-nucleoside triphosphate (NTP) peak and an increase in the phosphocreatine (PCr) peak, as measured by phosphorus 31P-MRS, in brain of healthy human subjects. Fifteen healthy male subjects (age=22.9+/-2.2; body mass index=22.9+/-1.7), who were without any axis I disorders or physical or neurological illness, were recruited. Ten subjects took creatine-monohydrate, 0.3 g/kg/day for the first 7 days and 0.03 g/kg/day for the next 7 days (creatine group). Five comparison subjects took equivalent amounts of sucrose as placebo (placebo group). Both 1H- and 31P-MRS scans were acquired at baseline, as well as at day 7 and day 14 of oral supplementation. 1H-MRS: Water suppressed localized spectra were acquired using a single-voxel (1.5 cm x 2 cm x 2 cm) proton MRS PRESS sequence in the left frontal lobe. 31P-MRS: Phosphorus spectral data were recorded from a 5-cm-thick axial brain slice using a short-TE slice selective spin-echo pulse sequence. The creatine group had significantly increased brain creatine levels (8.1% and 9.3%, in creatine/N-acetyl aspartate and creatine/choline ratios, respectively) compared to the placebo group over the 2-week period. The creatine group had significantly decreased beta-NTP levels (7.8%) and marginally increased PCr (3.4%) over the same period. In addition, the brain inorganic phosphate level increased over the same period in the creatine group (9.8%). The current study is the first multinuclear (1H and 31P) MRS study to evaluate changes in brain high-energy phosphate metabolism following oral creatine supplementation in healthy human subjects. These findings suggest the possibility of using oral creatine supplementation to modify brain high-energy phosphate metabolism in subjects with various brain disorders, including major depression, schizophrenia, cocaine and opiate abuse, where alterations in brain high-energy phosphate metabolism have been reported.

Administration, Oral↗

PubMedDate not supplied

Reliability and validity of the Korean version of the Temperament and Character Inventory.

The purpose of this study was to evaluate the reliability and validity of the Korean version of the Temperament and Character Inventory (TCI), a self-report questionnaire based on Cloninger's biosocial model of personality. The TCI was translated into Korean and administered to 851 Korean college students. A test-retest study of the TCI was conducted across a 3-month interval with 130 subjects. Internal consistency was calculated by Cronbach alpha. Test-retest reliability was analyzed by Pearson correlation analysis. Factor analyses for the temperament and character dimensions were performed using principal component analysis, rotating factors obliquely by promax. A comparison of TCI scores between Korean and United States college students was done using independent t tests. Cronbach alpha values for the TCI scales ranged from.60 to.85 for the temperament scales and from.82 to.87 for the character scales. Test-retest correlations (r) ranged from.52 to.72 for the temperament scales and from.52 to.71 for the character scales. Principal component factor analyses showed similar factor structures of four temperaments and three characters as the American version of the TCI, except for the Reward Dependence and Persistence temperament scales. Explorative factor analysis with a condition of eigenvalue greater than 1 produced five factors, as compared to seven factors extracted in Cloninger's original report. Results using a preset seven-factor solution was forced and did not successfully extract Cloninger's seven factors. Korean college students had higher mean scores on Harm Avoidance and lower mean scores on the rest of the scales as compared to a sample of US college students. The results of this study confirm that the Korean TCI has satisfactory psychometric properties and reflects Cloninger's biosocial model of personality.

Adult↗