Biomedical subjects

Jong Min Lee

Publications and source records attributed to Jong Min Lee.

At least 19 recordsLinked to original sources

PubMed2006

Functional expression of recombinant canstatin in stably transformed Drosophila melanogaster S2 cells.

We describe the expression and in vitro activity of recombinant canstatin from stably transformed Drosophila melanogaster S2 cells. Southern blot analysis indicated that transformed S2 cells contained multiple copies of the canstatin gene in the genome. Recombinant canstatin with a molecular weight of 29kDa was secreted into the culture medium. Recombinant canstatin was purified to homogeneity using a simple one-step Ni(2+) affinity fractionation. Purified recombinant canstatin inhibited human umbilical vein endothelial cell proliferation in a dose-dependent manner. The concentration at half-maximum inhibition (ED(50)) for recombinant canstatin expressed in stably transformed Drosophila S2 cells was approximately 0.37mug/ml. A maximum production level of 76mg/l of recombinant canstatin was obtained in a T-flask culture of Drosophila S2 cells 6 days after induction with 0.5mM CuSO(4).

Amino Acid Sequence↗

PubMed2006

Flux balance analysis in the era of metabolomics.

Flux balance analysis (FBA) has emerged as an effective means to analyse biological networks in a quantitative manner. Much progress has been made on the extension of FBA to incorporate a priori biological knowledge, provide more practical descriptions of observed cell behaviours, and predict the outcome of network perturbations. Metabolomics is independently advancing as a set of high-throughput data acquisition tools providing dynamic profiles of metabolites in an unbiased manner. These data sets are neither yet sufficiently comprehensive nor accurate enough for generating large-scale kinetic models. Thus, there is a pressing need to develop quantitative techniques that can make use of the emerging data and embrace the associated uncertainties. This article reviews recent advances in FBA to meet this need and discusses the utility of FBA as a complement to metabolomics and the expected synergy as a result of combining these two techniques.

Animals↗

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

[A randomized, prospective, comparative, multicenter study of rabeprazole and ranitidine in the treatment of reflux esophagitis].

BACKGROUND/AIMS: This study was done to evaluate the efficacy of rabeprazole (proton-pump-inhibitor) and ranitidine (H(2)-receptor antagonist) in the symptom relief and treatment of erosive esophagitis diagnosed by endoscopy. METHODS: A total of 110 patients with typical gastroesophageal reflux disease (GERD) symptoms were enrolled in this multicenter study. They were randomized into rabeprazole group (53 patients) and ranitidine group (57 patients) respectively. The patients in rabeprazole group were given 10 mg of rabeprazole and ranitidine group received 300 mg of ranitidine before breakfast and dinner for 8 weeks. After the end of treatment, we evaluated the endoscopic healing rate of reflux esophagitis and symptomatic improvement. RESULTS: After 8 weeks of treatment, rabeprazole group showed significantly higher complete endoscopic cure rate than ranitidine group (86.8% [46/53] vs. 57.9% [33/57], p=0.001) and higher symptomatic improvement of heartburn (91.2% [31/34] vs. 76.2% [32/42], p=0.085), especially in the first 7 days (76.7% vs. 45.3%, p=0.008). Also, rabeprazole group showed significantly higher improvement of regurgitation symptom than ranitidine group (100% [35/35] vs. 83% [39/47], p=0.009). Both group showed no differences in the improvement of chest pain and globus sensation. All the adverse events (rabeprazole group 4 events vs. ranitidine group 3 events) were mild and there was no abnormality in laboratory test. CONCLUSIONS: In patients with GERD, rabeprazole 10 mg b.i.d. is superior to ranitidine 300 mg b.i.d. in healing of reflux esophagitis and resolving typical GERD symptoms. Rabeprazole is an effective and well-tolerated drug for GERD treatment.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2005

Expression and characterization of recombinant beta-secretase from Trichoplusia ni BTI Tn5B1-4 cells transformed with cDNAs encoding human beta1,4-galactosyltransferase and Gal beta1,4-GlcNAc alpha 2,6-sialytransferase.

Beta-Secretase (betaSEC) was expressed in Trichoplusia ni BTI Tn5B1-4 (Tn5B1-4) cells transformed with cDNAs encoding beta1,4-galactosyltransferase (GalT) and Gal beta1,4-GlcNAc alpha 2,6-sialyltransferase (ST). The apparent molecular weight of recombinant beta-secretase was increased from 57 to 59 k Da. A lectin blot analysis indicated that recombinant beta-secretase from Tn5B1-4 betaSEC/GalT-ST cells (Tn5B1-4 cells co-transformed with cDNAs encoding beta-secretase, glycosyltransferases, GalT, and ST) contained the glycan residues of beta1,4-linked galactose and alpha2,6-linked sialic acid. Two-dimensional electrophoresis revealed that recombinant beta-secretase from Tn5B1-4 beta SEC/GalT-ST cells had a lower isoelectric point than beta-secretase from control Tn5B1-4 betaSEC cells (Tn5B1-4 cells transformed only with beta-secretase cDNA). The enzyme activity of recombinant beta-secretase from Tn5B1-4 betaSEC/GalT-ST cells was enhanced up to 77% compared to control Tn5B1-4 betaSEC cells. The concentrations at half-maximum inhibition (IC(50)) values estimated from inhibition analyses using purified beta-secretases from Tn5B1-4/betaSEC and Tn5B1-4/betaSEC/GalT-ST cells were 32 and 290 nM, respectively.

Amyloid Precursor Protein Secretases↗

PubMed2005

Automated 3-D extraction and evaluation of the inner and outer cortical surfaces using a Laplacian map and partial volume effect classification.

Accurate reconstruction of the inner and outer cortical surfaces of the human cerebrum is a critical objective for a wide variety of neuroimaging analysis purposes, including visualization, morphometry, and brain mapping. The Anatomic Segmentation using Proximity (ASP) algorithm, previously developed by our group, provides a topology-preserving cortical surface deformation method that has been extensively used for the aforementioned purposes. However, constraints in the algorithm to ensure topology preservation occasionally produce incorrect thickness measurements due to a restriction in the range of allowable distances between the gray and white matter surfaces. This problem is particularly prominent in pediatric brain images with tightly folded gyri. This paper presents a novel method for improving the conventional ASP algorithm by making use of partial volume information through probabilistic classification in order to allow for topology preservation across a less restricted range of cortical thickness values. The new algorithm also corrects the classification of the insular cortex by masking out subcortical tissues. For 70 pediatric brains, validation experiments for the modified algorithm, Constrained Laplacian ASP (CLASP), were performed by three methods: (i) volume matching between surface-masked gray matter (GM) and conventional tissue-classified GM, (ii) surface matching between simulated and CLASP-extracted surfaces, and (iii) repeatability of the surface reconstruction among 16 MRI scans of the same subject. In the volume-based evaluation, the volume enclosed by the CLASP WM and GM surfaces matched the classified GM volume 13% more accurately than using conventional ASP. In the surface-based evaluation, using synthesized thick cortex, the average difference between simulated and extracted surfaces was 4.6 +/- 1.4 mm for conventional ASP and 0.5 +/- 0.4 mm for CLASP. In a repeatability study, CLASP produced a 30% lower RMS error for the GM surface and a 8% lower RMS error for the WM surface compared with ASP.

Algorithms↗

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

Development of Korean standard brain templates.

We developed age, gender and ethnic specific brain templates based on MR and Positron-Emission Tomography (PET) images of Korean normal volunteers. Seventy-eight normal right-handed volunteers (M/F=49/29) underwent 3D T1-weighted SPGR MR and F-18-FDG PET scans. For the generation of standard templates, an optimal target brain that has the average global hemispheric shape was selected for each gender. MR images were then spatially normalized by linear transformation to the target brains, and normalization parameters were reapplied to PET images. Subjects were subdivided into 2 groups for each gender: the young/midlife (<55 yr) and the elderly groups. Young and elderly MRI/PET templates were composed by averaging the spatially normalized images. Korean templates showed different shapes and sizes (mean length, width, and height of the brains were 16.5, 14.3 and 12.1 cm for man, and 15.6, 13.5 and 11.4 cm for woman) from the template based on Caucasian (18.3, 14.2, and 13.3 cm). MRI and PET templates developed in this study will provide the framework for more accurate stereotactic standardization and anatomical localization.

Adolescent↗

PubMed2004

Gray matter abnormalities in paranoid schizophrenia and their clinical correlations.

Numerous imaging studies have shown structural brain abnormalities in schizophrenia. Recently, voxel-based morphometry enabled whole brain analysis beyond the regions of interest (ROI). Regional gray matter concentrations of magnetic resonance (MR) images from 35 patients with paranoid schizophrenia were compared with those from 35 age- and sex-matched controls, and their clinical correlations were explored using voxel-based morphometry. Gray matter concentrations in the patients were significantly reduced in the left insular and dorsolateral prefrontal regions, and bilaterally in the medial frontal, anterior cingulate, inferior frontal and superior temporal regions. On the other hand, gray matter concentrations in the bilateral cerebellum and right striatum were significantly increased in the patients compared with controls. A negative correlation between the score for the severity of 'lack of insight and judgment' and gray matter concentrations in the left posterior and right anterior cingulate and bilateral inferior temporal regions including the lateral fusiform gyri was found. These results suggest the important roles of the paralimbic structures in the pathophysiology of schizophrenia and the involvement of the perceptual and monitoring systems in the mechanism of insight.

Adult↗

PubMed2004

Improved production of recombinant tumstatin in stably transformed Trichoplusia ni BTI Tn 5B1-4 cells.

We describe the expression and in vitro activity of recombinant tumstatin from stably transformed Trichoplusia ni BTI Tn 5B1-4 cells. Recombinant tumstatin was secreted into a culture medium with a molecular weight of 29 kDa. Recombinant tumstatin was also purified to homogeneity using a simple one-step Ni2+ affinity fractionation. Purified recombinant tumstatin inhibited endothelial cell proliferation in a dose-dependent manner. The concentration at half-maximum inhibition (ED50) for recombinant tumstatin expressed in stably transformed Tn 5B1-4 cells was approximately 0.76 microg/ml. A maximum production level of 4.0 mg/l recombinant tumstatin was obtained in a T-flask culture of Tn 5B1-4 cells, 6 days after cultivation. We also investigated the individual effects of both dimethyl sulfoxide (DMSO) and sodium butyrate on recombinant tumstatin production in stably transformed Tn 5B1-4 cells. Supplementing cultures with DMSO and sodium butyrate separately increased recombinant tumstatin production in stably transformed Tn 5B1-4 cells by 117 and 32%, respectively.

Animals↗

PubMed2004

Theophylline increases the uptake of radioiodine by mouse thyroid.

Diagnostic and therapeutic use of radioiodine in the management of thyroid disorders depends on the ability of thyroid cells to concentrate radioiodine, a process that is regulated by the intracellular increase in cAMP. We hypothesized that theophylline, a drug known to increase intracellular cAMP via inhibition of phosphodiesterase, could increase thyroidal radioiodine uptake. We tested this effect in vivo, using C57BL/6j mice, and in vitro, using Fisher rat thyroid (FRTL-5) cells. One mouse received 2.5mg theophylline i.p., whereas a control mouse received only saline. Twenty-hours after theophylline, mice were injected with 10 microCi Na125I in 0.1 mL saline through the tail vein. Mean thyroidal 125I activity was 3.3-fold higher in theophylline-treated mice than in their respective controls. Radioiodine uptake and intracellular cAMP production of FRTL-5 cells were increased by a relatively low concentration of theophylline (1 microM). Intracellular cAMP increased up to 30 min and then declined in response to 1 microM theophylline. Sera from theophylline-treated mice stimulated 125I uptake and intracellular cAMP production by FRTL-5 cells. These findings show that theophylline can enhance radioiodine uptake by thyrocytes in vivo and in vitro. The in vitro effects of theophylline on both radioiodine uptake and cAMP production in a dose-dependent manner are consistent with an action mediated by phosphodiesterase inhibition.

Animals↗

PubMed2004

[A case of chronic acalculous cholecystitis diagnosed by delayed contrast emptying in gallbladder].

Chronic acalculous cholecystitis is a diagnosis of exclusion in patients complaining acalculous biliary pain. The possible causes of acalculous biliary pain are chronic gallbladder (GB) inflammation, GB dysfunction, cholesterolosis, cystic duct stenosis or microlithiasis. Recently, laparoscopic cholecystectomy is the choice of treatment for acalculous biliary pain. We experienced a 32-year-old woman whose initial symptoms were right upper quadrant pain and nausea only. The abdominal computed tomography, DISIDA scan, and upper and lower endoscopic examinations were nonspecific. Up to 48 hours after endoscopic retrograde cholangiopancreatography, contrast emptying of GB was delayed, implying dysfunctional GB. As the patient's right upper quadrant pain and tenderness became aggravated, the laparoscopic cholecystectomy was done and the final diagnosis of chronic acalculous cholecystitis was confirmed.

Acalculous Cholecystitis↗

PubMed2004

[A case of gastric metastasis from small cell lung carcinoma].

Gastric metastasis of lung carcinoma is a rare entity which is detected mostly at autopsy. Patients diagnosed as having those on lifetime are extremely rare. In addition to our case, 54 cases of lung carcinoma metastasis to the gastro-intestinal tract have been reported in the literature since 1961. We report a case of gastric metastasis originated from small cell lung carcinoma. The patient was a 87-year-old man. He refused lung biopsy and further treatment and died 2 months after the diagnosis. This is the case of gastric metastasis originated from lung carcinoma, which was confirmed by immunohistochemical staining.

Aged↗

PubMed2003

Morphometric abnormality of the insula in schizophrenia: a comparison with obsessive-compulsive disorder and normal control using MRI.

The insula is increasingly the subject of great interest in psychiatric disorders of neurodevelopmental origin because of its anatomical location, wide interconnectivity, and variety of functions. This study explores the possible morphometric change of the insula in schizophrenia and obsessive-compulsive disorder (OCD), and its potential relationship to clinical symptoms. The insula was traced on all coronal slices of magnetic resonance images of three age- and sex-matched diagnostic groups, which consisted of 21 patients with schizophrenia, 21 patients with OCD and 21 normal volunteers. The volumetric measures of the insula were compared among the three groups, and their relationships to the symptom severity were investigated. Volumetric reduction of the left insula was observed in the schizophrenia group, but not in the OCD group. These results confirm the involvement of deficient insular function in the pathophysiology of schizophrenia.

Adult↗

PubMed2003

Follicular expression of c-Kit/SCF and inhibin-alpha in mouse ovary during development.

The mechanism of development of the ovarian follicles has been largely unknown. We performed an immunohistochemical (IHC) study to determine the follicular expressions of c-kit, SCF, and inhibin-alpha at different developmental stages in mouse ovary. Ovaries were obtained from 14 and 16 days post coitum and 2, 7, and 21 days post partum (dpp) mice. IHC for c-kit, SCF, and inhibin-alpha was carried out. c-Kit and SCF were expressed on oogonia regardless of the developmental stage. Immunoreactive c-kit and SCF antigens were expressed on oocytes of primordial and primary follicles of neonate mouse ovaries. In 21 dpp mouse ovary, the expression of c-kit/SCF in oocytes gradually decreased as the follicles developed. c-Kit/SCF was expressed strongly in oocytes of preantral follicles and weakly in granulosa and thecal cells. Inhibin-alpha was mainly expressed on granulosa cells of preantral and early antral follicles of the 21 dpp mouse ovaries. These findings suggest that the IHC expression of c-kit/SCF proteins is specific in all developmental stages of ovarian follicles and is decreased after the follicle starts to grow. The expression of inhibin-alpha is negatively correlated with the expression of c-kit/SCF in the ovarian follicles in mice.

Animals↗

PubMed2002

Induction of apoptosis and caspase-3 activation by chemopreventive [6]-paradol and structurally related compounds in KB cells.

[6]-paradol, a pungent phenolic substance found in ginger and other Zingiberaceae plants, has been demonstrated to be an effective inhibitor of tumor promotion in mouse skin carcinogenesis. In the present study, we found that [6]-paradol and other structurally related derivatives, [10]-paradol, [3]-dehydroparadol, [6]-dehydroparadol, and [10]-dehydroparadol, with the exception of [3]-paradol induce apoptosis in an oral squamous carcinoma cell line, KB, in a dose-dependent manner. [10]-paradol and [10]-dehydroparadol exhibited a similar extent of cytotoxicity to that of [6]-paradol. [6]-Dehydroparadol and [3]-dehydroparadol appeared to be more potent, with an IC50 less than 40 microM. Treatment of KB cells with an apoptosis-inducing concentration of [6]-dehydroparadol caused induction of proteolytic cleavage of pro-caspase-3. These results suggest that [6]-paradol and structurally related derivatives induce apoptosis through a caspase-3-dependent mechanism.

Antineoplastic Agents↗

PubMed2002

Detrended fluctuation analysis of EEG in sleep apnea using MIT/BIH polysomnography data.

A number of natural time series including electroencephalogram (EEG) show highly non-stationary characteristics in their behavior. We analyzed the EEG in sleep apnea that typically exhibits non-stationarity and long-range correlations by calculating its scaling exponents. Scaling exponents of the EEG dynamics are obtained by analyzing its fluctuation with detrended fluctuation analysis (DFA), which is suitable for non-stationary time series. We found the mean scaling exponents of EEG is discriminated according to Non-REM, REM (Rapid Eye Movement) and waken stage, and gradually increased from stage 1 to stage 2, 3 and 4.

Cerebral Cortex↗

PubMed2002

The effect of bone marrow transplantation on the osteoblastic differentiation of human bone marrow stromal cells.

Osteoporosis is a serious and relatively common complication of transplantation procedures. However, little is known about the exact mechanism or severity of osteoporosis complicated by bone marrow transplantation (BMT). We conducted both ex vivo and clinical studies to identify the mechanism and extent of bone loss after BMT. In a prospective clinical study, we intended to identify the changes in bone turnover markers and bone mineral density (BMD) after BMT. During a 1-yr follow-up, BMD was measured before BMT and 1 yr after BMT in 67 patients undergoing BMT. Biochemical markers of bone formation and resorption were measured in all patients at short-term intervals during the yearlong follow-up. In ex vivo study, we cultured human bone marrow cells of normal controls and BMT recipients in osteogenic medium and compared their osteogenic potential. Using a DNA fingerprinting method, we also investigated the origin of bone marrow stromal cells that were harvested 3-4 wk after BMT. In a clinical study of 67 patients undergoing BMT, the mean serum carboxy-terminal cross-linked telopeptide of type I collagen increased progressively until 4 wk after BMT. Thereafter, it began to decrease and reached basal values after 1 yr. Serum osteocalcin decreased progressively until 3 wk after BMT and reached basal values after 3 months. One year after BMT, lumbar spine BMD had decreased by 3.3% (P < 0.05), and total proximal femoral BMD had decreased by 8.9% (P < 0.001). For the ex vivo study, bone marrow was obtained from healthy donors (n = 7) and transplant recipients (n = 7). Then, mononuclear cells including marrow stromal cells were isolated and cultured to osteoblastic lineage. Alkaline phosphatase activities of each group were measured by the time course of secondary culture, and the mineralizing potentials were compared between the two groups. Cells cultured in our system showed characteristics of osteoblast-like cells differentiated from marrow stromal cells. They were initially in a fibroblastic-like spindle shape and became cuboidal with the formation of nodules that were later confluent. The cells were stained to both alkaline phosphatase histochemistry and Von Kossa histochemistry, demonstrating that these cells were of osteoblastic lineage differentiating from marrow stromal cells. The mean time required for the near-confluence in the primary culture was 15 and 22.9 d in healthy donors and transplant recipients, respectively (P = 0.003). Alkaline phosphatase activity was significantly lower in the bone marrow recipients than in the healthy donors at d 7 and 10 of the secondary cultures. The period at which peak activity of alkaline phosphatase was reached was also delayed in the osteoblasts derived from BMT recipient bone marrow compared with those of healthy donors. Using Von Kossa histochemistry, much more mineralization was observed in osteoblasts of healthy donors than those of BMT recipients. After BMT, although the peripheral mononuclear cells in the recipients were of donor origin, the bone marrow stromal cells were of recipient origin according to the PCR analysis using YNZ 22 mini-satellite probe. In conclusion, the differentiation of bone marrow stromal cells into osteoblasts was impaired after BMT, and this might contribute to post-BMT bone loss.

Adolescent↗