Biomedical subjects

Dong-Hee Kim

Publications and source records attributed to Dong-Hee Kim.

At least 19 recordsLinked to original sources

PubMed2006

Effects of KIOM-79 on hyperglycemia and diabetic nephropathy in type 2 diabetic Goto-Kakizaki rats.

We investigated the effect of KIOM-79, 80% ethanolic extract of a new herbal prescription, on non-obese type 2 diabetic Goto-Kakizaki (GK) rats. The rats were treated orally with KIOM-79 (500 mg/kg body weight) once a day for 13 weeks to examine the long-term effects on hyperglycemia and glomerular histology as well as biochemical and functional abnormalities in kidney. As the results, we found that KIOM-79 reduced hyperglycemia (p<0.01), ameliorated insulin resistance (p<0.001), urinary protein excretion (p<0.01) and creatinine clearance (Ccr) (p<0.001), and inhibited glomerular AGE formation (p<0.001) in diabetic GK rats. We also found that KIOM-79 prevented the glomeruli enlargement, overexpression of type IV collagen (p<0.001), PKC protein (p<0.01), TGF-beta mRNA (p<0.05) and VEGF mRNA (p<0.05). Thus, based on our finding, KIOM-79 could reduce the hyperglycemia, and prevent or retard the development of diabetic nephropathy.

Administration, Oral↗

PubMed2006

Differential regulation of CC chemokine receptors by 9-cis retinoic acid in the human mast cell line, HMC-1.

Mast cells are well known as effector cells in a variety of inflammatory diseases, including asthma as well as other allergic disorders. The precise role of 9-cis retinoic acid (9CRA) in mast cells is not understood despite the accepted fact that 9CRA regulates inflammatory responses and neutrophil differentiation. In this study, we investigated the effects of 9CRA on the expression of CC chemokine receptors in the human mast cell line, HMC-1. 9CRA selectively inhibits the CCR2 mRNA level and increases the CCR3 mRNA level in both a time and dose dependent manner. Other CC chemokine receptors, including CCR1, CCR4 and CCR5 are not altered by treatment with 9CRA. Both TNF-alpha and LPS, known pro-inflammatory molecules, have no effect on mRNA levels of CC chemokine receptors. For surface expression, 9CRA decreased the CCR2 level but had no effect on the CCR3 level. 9CRA inhibited the chemotactic activity in response to the CCR2-dependent chemokine, MCP-1/CCL2 but not in response to CCR3-specific chemokine, eotaxin/CCL11. 9CRA decreased spontaneous homotype clustering. Therefore, our results demonstrate that 9CRA differentially decreases both CCR2 expression and chemotactic ability of HMC-1 cells, and may regulate the inflammatory effects of mast cells.

Alitretinoin↗

PubMed2006

Inhomogeneous substructures hidden in random networks.

We study the structure of the load-based spanning tree (LST) that carries the maximum weight of the Erdös-Rényi (ER) random network. The weight of an edge is given by the edge-betweenness centrality, the effective number of shortest paths through the edge. We find that the LSTs present very inhomogeneous structures in contrast to the homogeneous structures of the original networks. Moreover, it turns out that the structure of the LST changes dramatically as the edge density of an ER network increases, from scale free with a cutoff, scale free, to a starlike topology. These would not be possible if the weights are randomly distributed, which implies that topology of the shortest path is correlated in spite of the homogeneous topology of the random network.

Journal Article↗

PubMed2006

Malignant carcinoid tumor of the common bile duct: report of a case.

Carcinoid tumors of the extrahepatic bile duct are exceedingly rare and account for between 0.1% and 2% of all gastrointestinal carcinoid tumors, with most reported cases arising from the gallbladder. We herein present what we believe is only the 47th reported case of a primary carcinoid tumor occurring in the extrahepatic bile ducts. A 67-year-old woman sought treatment for obstructive jaundice accompanied by epigastric pain. Laboratory and imaging studies gave results that were consistent with a malignant obstruction in the common bile duct. We performed a pylorus-preserving pancreaticoduodenectomy. Pathologically, an ill-demarcated mass was noted in the common bile duct measuring 1.6 x 1.5 x 0.5 cm in size. The tumor had invaded the adjacent pancreatic tissues. Immunohistochemically, the mass demonstrated chromogranin, synaptophysin, and CD56 positivity. The final pathologic diagnosis was well-differentiated carcinoid tumor of a malignant nature. The patient, who underwent a curative surgical resection, was alive and disease-free at the time of writing.

Aged↗

PubMed2005

Systematic analysis of group identification in stock markets.

We propose improved methods to identify stock groups using the correlation matrix of stock price changes. By filtering out the market-wide effect and the random noise, we construct the correlation matrix of stock groups in which nontrivial high correlations between stocks are found. Using the filtered correlation matrix, we successfully identify the multiple stock groups without any extra knowledge of the stocks by the optimization of the matrix representation and the percolation approach to the correlation-based network of stocks. These methods drastically reduce the ambiguities while finding stock groups using the eigenvectors of the correlation matrix.

Journal Article↗

PubMed2005

Universality class of the fiber bundle model on complex networks.

We investigate the failure characteristics of complex networks within the framework of the fiber bundle model subject to the local load sharing rule in which the load of the broken fiber is transferred only to its neighbor fibers. Although the load sharing is strictly local, it is found that the critical behavior belongs to the universality class of global load sharing where the load is transferred equally to all fibers in the system. From the numerical simulations and the analytical approach applied to the microscopic behavior, it is revealed that the emergence of a single dominant hub cluster of broken fibers causes the global load sharing effect in the failure process.

Journal Article↗

PubMed2005

Antitumor activity of Pulsatilla koreana saponins and their structure-activity relationship.

Seventeen saponins isolated from the root of Pulsatilla koreana were examined for their in vitro cytotoxic activity against the human solid cancer cell lines, A-549, SK-OV-3, SK-MEL-2, and HCT15, using the SRB assay method, and their in vivo antitumor activity using BDF1 mice bearing Lewis lung carcinoma (LLC). The saponins 5-17, with a free acidic functional group at C-28 of aglycon, exhibited moderate to considerable cytotoxic activity, however, the saponins 1-4, esterified with a trisaccharide at C-28 of aglycon, did not exhibit cytotoxic activity (ED50; >300 microM). Among them, oleanolic acid 3-O-alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->4)]-alpha-L-arabinopyranoside (10) exhibited the most potent cytotoxic activity (ED50; 2.56, 2.31, 1.57, 8.36 microM, respectively). In vivo test, hederagenin 3-O-alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->4)]-alpha-L-arabinopyranoside (6, Inhibition Ratio, IR; 66.9%) exhibited more potent antitumor activity than taxol (IR; 35.8%) and doxorubicin (IR; 62.1%). Also, hedragenin 3-O-beta-D-glucopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->3)-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside (17, IR; 50.3%) exhibited potent antitumor activity. These two saponins were identically comprised of a hederagenin aglycon moiety and a sugar sequence O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside at C-3 of the hederagenin, suggesting that the two elements are essential factors for the antitumor activity.

Animals↗

PubMed2005

Investigation of early protein changes in the urinary bladder following partial bladder outlet obstruction by proteomic approach.

We investigated the pathophysiological mechanism by proteomic approach as a possible tool to detect the marker proteins to develop lower urinary tract symptoms following bladder outlet obstruction (BOO). Rats were randomized into 3 groups; control, sham operation and BOO groups. BOO group was divided into 1, 3, and 5 day-group. Conventional proteomics was performed with high resolution 2-D gel electrophoresis followed by computational image analysis and protein identification using mass spectrometry using rat urinary bladders. A comparison of bladder of BOO group with control bladder showed that three proteins of optineurin, thioredoxin and preprohaptoglobin were over-expressed in the bladder of BOO group. In addition, four proteins, such as peroxiredoxin 2, transgelin, hippocampal cholinergic neurostimulating peptide (HCNP) and beta-galactoside-binding lectin, were under-expressed in the bladder of BOO group. These data supported that downregulation of HCNP might make detrusor muscle be supersensitive to acetylcholine, up-regulation of optineurin means the protection of nerve injury, and down-regulation of transgelin means the decreased contractility of detrusor muscle. Beside these proteins, other proteins are related to oxidative stress or have a nonspecific function in this study. However more information is needed in human bladder tissue for clinical usage.

Animals↗

PubMed2004

Protein-bound polysaccharide from Phellinus linteus induces G2/M phase arrest and apoptosis in SW480 human colon cancer cells.

The cytotoxic mechanism of protein-bound polysaccharide isolated from Phellinus linteus (PL, Mesima) has been investigated. PL inhibited the proliferation and colony formation of SW480 human colon cancer cells. Flow cytometry analysis showed that PL increased the populations of both apoptotic sub-G1 and G2/M phase. The result obtained from TUNEL assay corroborated apoptosis which was shown in flow cytometry. Western blot analysis suggested that PL-induced apoptosis and growth inhibition were associated with decrease in Bcl-2, increase of the release of cytochrome c, and reduced expression of cyclin B1. These results suggest that PL has a direct antitumor effect through apoptosis and cell cycle blockade in certain cancer cells.

Antineoplastic Agents↗

PubMed2004

Scale-free trees: the skeletons of complex networks.

We investigate the properties of the spanning trees of various real-world and model networks. The spanning tree representing the communication kernel of the original network is determined by maximizing the total weight of the edges, whose weights are given by the edge betweenness centralities. We find that a scale-free tree and shortcuts organize a complex network. Especially, in ubiquitous scale-free networks, it is found that the scale-free spanning tree shows very robust betweenness centrality distributions and the remaining shortcuts characterize the properties of the original network, such as the clustering coefficient and the classification of scale-free networks by the betweenness centrality distribution.

Journal Article↗

PubMed2004

Methylene chloride fraction of Scutellaria barbata induces apoptosis in human U937 leukemia cells via the mitochondrial signaling pathway.

BACKGROUND: Scutellaria barbata D.Don has been applied to treat cancers, inflammation and urinary disease. However, its antitumor mechanism still remains unclear. METHODS: With methylene chloride fraction of Herba Scutellariae barbatae (MCSB), apoptosis-related experiments were carried out on human U937 leukemia cells by (a) 2,3-bis[2-4-nitro-5-sulphophenyl]2H-tetrazolium-5-carboxanilide (XTT) assay for cytotoxicity; (b) terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling (TUNEL) assay for morphological changes; (c) cell cycle analysis; (d) Western blot analysis of poly(ADP-ribose) polymerase (PARP), caspase-8, caspase-9, caspase-3 and Bax, Bcl-2 and cytochrome c expressions for apoptosis signaling pathway. RESULTS: MCSB inhibited the proliferation of human U937 leukemia cells in a dose-dependent manner (IC50 = approximately 10 microg/ml). MCSB dose-dependently increased the sub-G1 DNA contents by cell cycle analysis. DNA fragments indicating induction of apoptosis were observed in MCSB-treated U937 cells by TUNEL assay. Caspase-9 and caspase-3 were activated while caspase-8 was intact by MCSB. Similarly, MCSB effectively cleaved PARP, increased the ratio of Bax/Bcl-2 and released the cytochrome c from mitochondria during apoptosis in U937 cells. CONCLUSIONS: Our results suggest that MCSB can induce apoptosis via the mitochondria-mediated signaling pathway.

Apoptosis↗

PubMed2004

Isolation and anticomplement activity of compounds from Dendropanax morbifera.

Dendropanax morbifera Leveille (Araliaceae) is used in Korea for a variety of disease, such as migraine headache and dysmenorrhea. A new polyacetylene (1) and six known compounds (2-7) were isolated from the leaves of this plant by conventional chromatographic techniques. The structure of the new polyacetylene (1) was determined as (9Z,16S)-16-hydroxy-9,17-octadecadiene-12,14-diynoic acid by spectroscopic means including 2D NMR, which comprised the determination of a chiral by modified Mosher's ester method. Compounds 1-7 were investigated in vitro for their anticomplement activity against the classical pathway of the complement system. Of these, compound 1 showed significant anticomplement activity with 50% inhibitory concentration (IC50) value of 56.98 microM, whereas compounds 2-7 were inactive.

Araliaceae↗

PubMed2004

[Relationship between depression and resilience among children with nephrotic syndrome].

PURPOSE: The purposes of this study were to describe the relationship between depression and resilience and to identify variables associated with depression among children with nephrotic syndrome. METHOD: Data was collected from 45 children who were registered at one hospital in Seoul. The criteria for sample selection were 10 to 15 year-old children who were diagnosed at least 6 month prior. The instruments included a self-reported questionnaire on resilience by Kim, CDI by Beck, and MBRI by Kwak. Descriptive, Pearson correlation and multiple regression analyses were done. RESULT: The mean score of depression was 11.44 (range:0-54) and resilience was 97.47 (range:32-128). There were significant positive relationships between depression and age (r=0.302, p<.005) and academic achievement (r=-0.318, p<.005). In addition, negative relationships between depression and maternal attitude (r=-0.412, p<.001) and resilience (r=-0.649, p<.001) occurred. The results of multiple regression analysis showed that maternal behavior (beta=-0.421, p<.005) and resilience (beta=-0.639, p<.001) were related to depression. CONCLUSION: Children with higher resilience and with an affectionate mother were less depressed. Thus, it is important to identify strengths of children and help them to increase resilience and implement parenting and counseling programs for parents' of these children. Similar studies with children with other chronic illnesses are needed.

Adaptation, Psychological↗

PubMed2003

Mylabris phalerlata induces apoptosis by caspase activation following cytochrome c release and Bid cleavage.

Mylabris phalerata (MP) is an insect that has been used for the treatment of cancer in oriental medicine. In the present study, the butanol (BuOH) fraction of MP (BFMP) was examined to determine whether it can exert anti-cancer activity through an apoptotic pathway with little toxicity. BFMP was found to have a specific cytotoxic effect on human monocytic leukemic U937 cells (IC(50) = 140 microg/ml) rather than on peripheral blood mononuclear lymphocytes (PBML, IC(50) = over 500 microg/ml). BFMP also induced the morphological changes of apoptosis, such as chromatin condensation, cell shrinking and DNA fragmentation at a concentration of 31.25 microg/ml. In addition, BFMP significantly increased the portion of apoptotic annexin-V positive cells in a dose-dependent manner, and effectively activated caspases (cysteine aspartase) cascade involving caspases 8, 9 and 3. BFMP also effectively cleaved Bid, a death agonist member of the Bcl-2 family and (poly(ADP-ribose)polymerase) (PARP) and induced the subsequent release of cytochrome c from mitochondria into the cytosol. However, it did not affect Bcl-2 and Bax expression. Taken together, these data suggest that the BuOH extract of Mylabris phalerata can induce apoptosis in U937 cells by caspase cascade activation in conjunction with cytochrome c release, induced by a product of Bid. Therefore, we conclude that BFMP has anti-cancer activity, which is achieved through apoptosis and is associated with little toxicity.

Animals↗

PubMed2003

Blockade of calcium entry accelerates arsenite-mediated apoptosis in rat cerebellar granule cells.

Arsenical exposure can cause defects in the central nervous system, yet the underlying cellular and molecular mechanisms are largely unknown. We have recently demonstrated that sodium arsenite induces apoptosis of cultured cortical and cerebellar neurons, suggesting that arsenite-induced neuronal apoptosis may contribute to at least some of its neurotoxic effects. Here we investigated the effect of Ca2+ on arsenite-mediated cerebellar granule neuron death. Sodium arsenite induced apoptosis in cerebellar neurons which were maintained in the presence of serum and depolarizing concentrations of potassium chloride (25 mM KCI). Under these conditions, inhibition of calcium entry by N-methyl-D-aspartate (NMDA) receptor blocker DL-aminophosphonovalerate (APV) or calcium channel antagonist nifedipine increased arsenite-induced apoptosis, while APV or nifedipine alone had little effect on cell viability. In cortical neurons or cerebellar neurons maintained at low potassium (5 mM), arsenite also induced apoptosis. However, the addition of APV or nifedipine did not alter levels of arsenite-induced apoptosis. These data suggest that arsenite-mediated apoptosis is regulated by intracellular calcium levels.

Animals↗

PubMed2003

Anti-complement activity of constituents from the stem-bark of Juglans mandshurica.

Four known flavonoids and two galloyl glucoses isolated from the stem-bark of Juglans mandshurica (Juglandaceae), namely taxifolin (1), afzelin (2), quercitrin (3), myricitrin (4), 1,2,6-trigalloylglucose (5), and 1,2,3,6-tetragalloylglucose (6), were evaluated for their anti-complement activity against complement system. Afzelin (2) and quercitrin (3) showed inhibitory activity against complement system with 50% inhibitory concentrations (IC(50)) values of 258 and 440 microM. 1,2,6-Trigalloylglucose (5) and 1,2,3,6-tetragalloylglucose (6) exhibited anti-complement activity with IC(50) values of 136 and 34 microM. In terms of the evaluation of the structure-activity relationship of 3,5,7-trihydroxyflavone, compounds 2, 3, and 4 were hydrolyzed with naringinase to give kaempferol (2a), quercetin (3a), and myricetin (4a) as their aglycones, and these were also tested for their anti-complement activity. Of the three aglycones, kaempferol (2a) exhibited weak anti-complement activity with an IC(50) value of 730 microM, while quercetin (3a) and myricetin (4a) were inactive in this assay system. Among the compounds tested, 1,2,3,6-tetragalloylglucose (6) showed the most potent anticomplement activity (IC(50), 34 microM).

Animals↗

PubMed2003

Effects of ylang-ylang essential oil on the relaxation of rat bladder muscle in vitro and white rabbit bladder in vivo.

Current and primary treatment modality in overactive bladder includes the administration of anticholinergics. The demand for new agents has been rising since anticholinergics have proven to come with many side effects. This study was designed to investigate the effects of ylang-ylang essential oil (YYEO) on the relaxation of urinary bladder muscle in vitro and in vivo. Effects of YYEO were assessed on resting tension, and electrical field stimulation- and various drug-induced contraction in vitro by checking the isometric tension changes of muscle strips and same procedures were repeated in the presence of methylene blue, Nw-Nitro-L-arginine methyl ester hydrochloride (L-NAME), or N-ethylmaleimide, and in vivo. YYEO decreased significantly the contractility of strips. There was no statistically significant difference between the treated group only with YYEO and the pretreated group with YYEO and methylene blue or L-NAME. When N-ethylmaleimide was employed, there was a statistically significant decrease in the rate of contraction. In vivo studies showed the same results compared with in vitro study. The results of this study indicate that YYEO has a relaxing effect on the bladder, and such mechanism is thought to be brought about by a pathway mediated by c-AMP.

Animals↗

PubMed2002

Prognostic value of vascular endothelial growth factor in Stage IB carcinoma of the uterine cervix.

PURPOSE: To clarify the role of vascular endothelial growth factor (VEGF) expression as an independent prognostic factor in Stage IB cervical cancer. METHODS AND MATERIALS: A total of 117 patients with Stage IB cervical cancer who had undergone radical hysterectomy and pelvic lymph node dissection with complete histopathologic examination were included. Eighty-eight (75.2%) patients received postoperative radiotherapy and/or chemotherapy. VEGF expression was examined using immunohistochemistry. RESULTS: Of 117 patients, 35 (29.9%) showed high-intensity VEGF expression and 69 (59%) had a high score for area of VEGF expression. Strong correlations were found between high VEGF intensity and both deep stromal invasion (p = 0.01) and positive pelvic lymph nodes (p = 0.03). The area of VEGF expression was significantly associated with tumor size (p = 0.02). In a multivariate analysis, high VEGF intensity (p = 0.009) and tumor size (p = 0.01) were significant prognostic factors for overall survival and disease-free survival (p = 0.001 and p = 0.003, respectively). However, the area of VEGF expression was not a prognostic factor for overall survival or disease-free survival. CONCLUSION: Our findings on the correlation between VEGF expression and prognosis were conflicting. Functional and quantitative tools to assess tumor angiogenesis in addition to the expression of VEGF need to be developed and would be helpful to support the finding that tumor angiogenesis correlates significantly with prognosis in early-stage cervical cancer.

Adenocarcinoma↗