Biomedical subjects

Sung-Hoon Kim

Publications and source records attributed to Sung-Hoon Kim.

At least 37 records · Page 2Linked to original sources

PubMed2005

Chemopreventive properties of the ethanol extract of chinese licorice (Glycyrrhiza uralensis) root: induction of apoptosis and G1 cell cycle arrest in MCF-7 human breast cancer cells.

Much of the interest on the chemopreventive properties of licorice has been focused on the plant genius Glycyrrhiza glabra. In this study the ethanol extract of Chinese licorice root, Glycyrrhiza uralensis (G. uralensis) was investigated for its estrogenic effect and the ability to inhibit cell proliferation in the MCF-7 human breast cancer cell line. The extract of the root of G. uralensis was fractionated in EtOH:H(2)O (80:20) (80% ethanol). The extract exhibited estrogenic effects similar to 17beta- estradiol (E2) and induced apoptosis at the same dose level (100 microg/ml) in MCF-7 breast cancer cells, results were associated with up-regulation of tumor suppressor gene p53 and pro-apoptotic protein Bax. G. uralensis extract caused the up-regulation of p21(waf1/cip1) and down-regulation of cdk 2 and cyclin E and most significantly, induced G1 cell cycle arrest. This is the first study to show that the ethanolic extract of the root of G. uralensis has an estrogen-like activity and anti-cancer effects against MCF-7 human breast cancer cells. Whilst the use of phytoestrogens to protect against hormone-dependent cancers or as a 'natural' alternative to hormone replacement therapy remains controversial, the data in this paper support the suggestion that extracts of root of the Chinese licorice G. uralensis might be of importance in this debate.

Anticarcinogenic Agents↗

PubMed2005

Nerve regeneration with the use of a poly(l-lactide-co-glycolic acid)-coated collagen tube filled with collagen gel.

AIM: The aim of this study was to develop a novel artificial nerve conduit and to evaluate its efficiency based on the promotion of peripheral nerve regeneration in rabbits. MATERIAL AND METHODS: The nerve conduit was made of a poly (l-lactide-co-glycolic acid)-coated collagen tube filled with collagen gel. The conduits were implanted into a 15 mm gap in the peroneal nerves of five rabbits. On the contralateral side, the defects were bridged with collagen-filled vein grafts. RESULTS: Twelve weeks postoperatively nerve regeneration was superior to the vein graft in the PLGA-coated collagen tube, both morphologically and electrophysiologically. CONCLUSION: The results indicate the superiority of the PLGA-coated collagen tube over vein grafts. Furthermore, they show that entubulation repair with this type of tube can support nerve regeneration over a nerve gap distance of at least 15 mm.

Action Potentials↗

PubMed2005

Chinese cabbage extracts and sulforaphane can protect H2O2-induced inhibition of gap junctional intercellular communication through the inactivation of ERK1/2 and p38 MAP kinases.

The cruciferous vegetables such as Chinese cabbages and broccoli are known to have anticancer phytochemicals, and the consumption of cruciferous vegetables has been proposed to protect against various cancers. The anticarcinogenic properties of some Chinese cabbage extracts and sulforaphane glucosinolate (SFN) were assessed by examining their ability to prevent the inhibition of gap junctional intercellular communication (GJIC) induced by hydrogen peroxide (H2O2) in WB-F344 normal rat liver epithelial cells. The cells were preincubated with Chinese cabbage extracts and SFN for 24 h followed by cotreatment with cells and H2O2 (750 microM) for 1 h. Chinese cabbage extracts and SFN prevented the inhibition of GJIC and phosphorylation of gap junction protein connexin43 (Cx43) by H2O2 treatment. Chinese cabbage extracts and SFN were able to prevent the inhibition of GJIC through the blocking of Cx43 phosphorylaton and inactivation of ERK 1/2 and p38 MAP kinase. The results suggest that cruciferous vegetables and their components, SFN, may exert the anticancer effect by targeting the GJIC as a functional dietary chemopreventive agent.

Bidens↗

PubMed2005

Anti-thrombic activity of Korean herbal medicine, Dae-Jo-Whan and its herbs.

The anti-thrombic properties of the Korean herbal medicine, Dae-Jo-Hwan (DJW), which is consisted of 11 herbs (indicated as concentrations) of Rehmanniae radix 24%, Hominis placenta 5%, Testudinis carapax 9%, Eucommiae cortex 9%, Asparagi radix 9%, Phellodendri cortex 9%, Achyranthis radix 7%, Liriopis tuber 7%, Angelicae sinensis radix 7%, Ginseng radix 6%, and Schizandrae fructus 3%, were investigated. The extracts of DJW and its 11 herbs, except G. radix, A. sinensis radix and S. Fructus, inhibited the endotoxin-induced hepatic venous thrombosis in high cholesterol diet-treated rats. Also the extract inhibited the endotoxin-induced decrease in blood platelets and fibrinogen, and endotoxin-induced increase in fibrin degradation products (FDP) on disseminated intravascular coagulation in normal rats. In in vitro experiments, the extract was shown to have inhibitory effect on collagen- and ADP-induced blood platelet aggregation, on thrombin-induced conversion of fibrinogen to fibrin and on the activity of plasminogen or plasmin. In conclusion, the protection of extracts of Korean herbs on the ischemic infarction induced artificially might be related to their inhibitory effects on DIC, platelet coagulation and thrombic action.

Adenosine Diphosphate↗

PubMed2005

The role of p38 MAP kinase and c-Jun N-terminal protein kinase signaling in the differentiation and apoptosis of immortalized neural stem cells.

The two distinct members of the mitogen-activated protein (MAP) kinase family c-Jun N-terminal protein kinase (JNK) and p38 MAP kinase, play an important role in central nervous system (CNS) development and differentiation. However, their role and functions are not completely understood in CNS. To facilitate in vitro study, we have established an immortal stem cell line using SV40 from fetal rat embryonic day 17. In these cells, MAP kinase inhibitors (SP600125, SB202190, and PD98059) were treated for 1, 24, 48, and 72 h to examine the roles of protein kinases. Early inhibition of JNK did not alter phenotypic or morphological changes of immortalized cells, however overexpression of Bax and decrease of phosphorylated AKT was observed. The prolonged inhibition of JNK induced polyploidization of immortalized cells, and resulted in differentiation and inhibition of cell proliferation. Moreover, JNK and p38 MAP kinase but not ERK1/2 was activated, and p21, p53, and Bax were overexpressed by prolonged inhibition of JNK. These results indicate that JNK and p38 MAP kinase could play dual roles on cell survival and apoptosis. Furthermore, this established cell line could facilitate study of the role of JNK and p38 MAP kinase on CNS development or differentiation/apoptosis.

Animals↗

PubMed2005

Structural properties of benzimidazole cavitand and its selective recognition toward 4-methylbenzamide over 4-methylanilide.

The conformations and properties of cavitand 5 with four benzimidazole flaps are studied by (1)H NMR. The benzimidazole cavitand 5 can form very stable vase structures with an enforced concave cavity by intermolecular hydrogen bonding with four hydroxyl-containing molecules, X-OH, such as methanol (X = Me), acetic acid (X = CH(3)CO), and trifluoroacetic acid (X = CF(3)CO). The stronger hydrogen bond donor strengths of X-OH are, the stronger hydrogen bonds are formed between the NH and N atoms of the neighboring benzimidazole fragments and the more vase structures of 5.4HOX are stable. The annular tautomerism of 5 in CDCl(3)/CD(3)OD (9:1, v/v) due to the proton exchange between NH and N atoms of the neighboring benzimidazole fragments is observed by 400 MHz (1)H NMR, and the free energy of activation is measured as DeltaG++(210) = 10.2 kcal/mol at a coalescence temperature of 210 K. Cavitand 5 forms inclusion complexes with 4-methylbezamide guests such as 4-methyl-N-p-tolylbenzamide 6 and N,4-dimethylbenzamide 7 in water-saturated CDCl(3). However, an isomorphic 4-methylanilide guest such as N-4-tolylacetamide 8 cannot be recognized in the concave cavity of 5. This high selectivity toward 4-methylbenzamide over 4-methylanilide seems attributable to the hydrogen-binding interaction between the NH proton of 4-methylbezamide guest 7 and the oxygen atom of the closest water molecule.

Journal Article↗

PubMed2005

Mesenteric Castleman's disease.

We report here a rare case of mesenteric Castleman's disease presenting as a mesenteric mass. A 13-year-old female child was admitted to our hospital complaining of intermittent vague abdominal pain. She had hypochromic anemia, thrombocytosis and an elevated erythrocyte sedimentation rate (ESR). Ultrasonography and computed tomography indicated an intra- abdominal mass might represent a lymphoma or gastrointestinal stromal tumor or leiomyoma, but the definitive preoperative diagnosis couldn't be confirmed. The surgical resection of the mass revealed the mesenteric hyaline vascular-type Castleman's disease.

Adolescent↗

PubMed2005

Penta-O-galloyl-beta-D-glucose suppresses tumor growth via inhibition of angiogenesis and stimulation of apoptosis: roles of cyclooxygenase-2 and mitogen-activated protein kinase pathways.

Recent studies have revealed that 1,2,3,4,6-penta-O-galloyl-beta-d-glucose (PGG) has anti-tumorigenic activity in vitro. In the present work, we evaluated the in vitro and in vivo antiangiogenic and antitumor activities of PGG and examined its molecular mechanisms. PGG significantly inhibited the proliferation and tube formation in basic fibroblast growth factor (bFGF)-treated human umbilical vein endothelial cells (HUVECs) at non-cytotoxic concentrations. PGG effectively disrupted the bFGF-induced neo-vascularization in chick chorioallantoic membrane (CAM) and in Matrigel plugs in the mice. When mice were intraperitoneally injected, PGG also significantly inhibited tumor angiogenesis induced by Lewis lung carcinoma (LLC) and the growth of LLC by 57 and 91% of control tumor weight at 4 and 20 mg/kg, respectively. Immunohistochemical analysis revealed decreased microvessel density, decreased expression of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF), reduced tumor cell proliferation and increased tumor cell apoptosis. Similarly, PGG significantly attenuated the expression of COX-2 and VEGF and reduced the secretion of VEGF and prostaglandin E2 in bFGF-treated HUVECs. Furthermore, the COX-2 inhibitor NS398 significantly inhibited tube formation and neo-vascularization in CAM, supporting the role of COX-2 in PGG inhibition of angiogenesis. PGG diminished the phosphorylation of extracellular signal regulated kinase 1/2, Jun NH2-terminal kinase and activated phospho-p38 mitogen-activated protein kinase (MAPK) in a dose-dependent manner in bFGF-treated HUVECs. In addition, p38 inhibitor SB203580 abolished the downregulation of COX-2, VEGF and the antiproliferative activity by PGG. Taken together, our data demonstrate that PGG exerts antitumor activity primarily via inhibition of angiogenesis through COX-2 and MAPK- dependent pathways.

Angiogenesis Inhibitors↗

PubMed2005

Autologous fibrin glue in peripheral nerve regeneration in vivo.

The activity of several growth factors on peripheral nerve regeneration is reported. Autologous fibrin glue contains a large number of platelets, which release significant quantities of growth factors. In order to understand the role of autologous fibrin glue in peripheral nerve regeneration, a 15-mm rabbit peroneal nerve defect was repaired using a vein graft filled with autologous fibrin glue. Axonal regeneration was examined using histological and electrophysiological methods. The extent of axonal regeneration was superior when treated with autologous fibrin glue. Our data suggest that fibrin nets formed by fibrinogen, in combination with growth factors present in autologous fibrin glue, might effectively promote peripheral nerve regeneration in nerve defects.

Animals↗

PubMed2005

Complete 1H and 13C NMR spectral assignment of symmetric and asymmetric bis-spiropyran derivatives.

(1)H and (13)C NMR spectra of symmetric and asymmetric bis-spiropyrans, Series 1-3, were completely assigned. Especially, the (1)H assignment of asymmetric spiropyrans was achieved by utilizing (1)H-(1)H COSY and nOe experiments. All of the carbons in the dye molecules were investigated through a combination of heteronuclear 2D-shift correlation spectroscopy (HETCOR), together with an attached proton test (APT).

Benzopyrans↗

PubMed2005

Iridoid glycosides isolated from Oldenlandia diffusa inhibit LDL-oxidation.

An iridoid glycoside, oldenlandoside III (5) was isolated from the n-butanol fraction of methanol extracts of the aerial parts of Oldenlandia diffusa Roxb. along with six others previously characterized iridoid glycosides; geniposidic acid (1), scandoside (2), feretoside (3), 10-omicron-benzoylscandoside methyl ester (4), asperulosidic acid (6) and deacetylasperulosidic acid (7). Compounds 1, 2, and 7 inhibited LDL-oxidation, and showed 63.3+/-2.0, 62.2+/-1.6, and 63.8+/-1.5% inhibition, respectively, at a concentration of 20 microg/mL.

Glucosides↗

PubMed2005

Inhibitory activity of isorhamnetin from Persicaria thunbergii on Farnesyl Protein Transferase.

The methanolic extract of the aerial parts of Persicaria thunbergii was found to show inhibitory activity on Farnesyl Protein Transferase (FPTase). Bioassay-guided fractionation of the methanolic extract resulted in the isolation of isorhamnetin, as an inhibitor on FPTase. This compound inhibited FPTase activity in a dose-dependent manner, and the IC50 value of isorhamnetin was 37.5 microM.

Alkyl and Aryl Transferases↗

PubMed2005

Ergosterol peroxide from flowers of Erigeron annuus L. as an anti-atherosclerosis agent.

Flowers of Erigeron annuus L. were extracted with 80% aqueous MeOH, and the concentrated extract was partitioned with EtOAc, n-BuOH, and H2O. Repeated silica gel and ODS column chromatography of the EtOAc fraction led to the isolation of a sterol, through activity-guided fractionation, using ACAT inhibitory activity measurements. From the physico-chemical data, including NMR, MS, and IR, the chemical structure of the compound was determined to be an ergosterol peroxide (1), which has been isolated for the first time from this plant. This compound exhibited hACAT-1 and Lp-PLA2 inhibitory effects, with inhibitory values of 51.6 +/- 0.9 and 51.7 +/- 1.2%, at a treatment concentration of 0.23 mM.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗

PubMed2005

Triterpenoids from the flower of Campsis grandiflora K. Schum. as human acyl-CoA: cholesterol acyltransferase inhibitors.

The flower of Campsis grandiflora K. Schum. was extracted with 80% aqueous MeOH, and the concentrated extract was partitioned with EtOAc, n-BuOH and H2O. From the EtOAc fraction, seven triterpenoids were isolated through the repeated silica gel, ODS column chromatographies and preparative HPLC. From the result of physico-chemical data including NMR, MS and IR, the chemical structures of the compounds were determined as 3beta-hydroxyolean-12-en-28-oic acid (oleanolic acid, 1), 3beta-hydroxyurs-12-en-28-oic acid (ursolic acid, 2), 3beta-hydroxyurs-12-en-28-al (ursolic aldehyde, 3), 2alpha,3beta-dihydroxyolean-12-en-28-oic acid (maslinic acid, 4), 2alpha,3beta-dihydroxyurs-12-en-28-oic acid (corosolic acid, 5), 3beta,23-dihydroxyurs-12-en-28-oic acid (23-hydroxyursolic acid, 6) and 2alpha,3beta,23-trihydroxyolean-12-en-28-oic acid (arjunolic acid, 7). These teriterpenoids were isolated for the first time from this plant. Also, compounds 4, 5, 6, and 7 revealed relatively high hACAT-1 inhibitory activity with the value of 46.2+/-1.1, 46.7+/-0.9, 41.5+/-1.3 and 60.8+/-1.1% at the concentration of 100 microg/mL, respectively.

Bignoniaceae↗

PubMed2005

Induction method of tyrosine kinase A-mediated cell death in rat pheochromocytoma.

Nerve Growth Factor (NGF) is a neurotrophic factor that prevents apoptosis in neuronal progenitor cells. In rat pheochromocytoma (PC12) cells, tyrosine kinase A receptor (TrkA) mediates neurotrophic or protective effects, while p75 neurotrophin receptor (p75NTR) functions as a death receptor. We have determined whether TrkA mediates any cytotoxic effect. Following serum deprivation, TrkA expression increased 2.2-fold and apoptosis began with expression of Bax proapoptotic protein. Application of NGF halved cell viability but this was reversed by K252a, the TrkA inhibitor. These results confirmed the paradoxical cytotoxic effect of neurotrophic NGF via TrkA in PC12 cells following serum deprivation.

Animals↗

PubMed2005

Nerve repair using a vein graft filled with collagen gel.

It has been shown that a vein graft provides a good environment for axon regeneration in short nerve gaps. But the use of a vein graft for long nerve gaps is controversial because veins may collapse, due to their thin walls, and the surrounding scar tissue can cause constriction. In an attempt to improve results using the vein graft, the authors conducted the reported experiment by filling the lumen of the vein with collagen gel. A 15-mm rabbit peroneal nerve defect was bridged with a collagen-filled vein graft. On the contralateral side, the defect was bridged with the vein alone. When the regenerated tissue was examined 4 weeks, 8 weeks, and 12 weeks after grafting, the number and diameter of myelinated fibers were significantly increased, compared with the control group without collagen gel. This study found that in order to increase the efficacy of a vein graft for axonal regeneration, collagen gel might be an appropriate matrix material with which to fill the vein graft.

Animals↗

PubMed2005

Involvement of c-Jun N-terminal kinase in G2/M arrest and caspase-mediated apoptosis induced by sulforaphane in DU145 prostate cancer cells.

Sulforaphane (SFN) is a major isothiocyanate compound in cruciferous vegetables such as broccoli, cauliflower, and Brussels sprouts. Preclinical animal models have recently shown that SFN and other isothiocyanates may be useful for prostrate cancer (PCa) chemoprevention. In this study we used a DU145 human PCa cell culture model to investigate the role of protein kinase signaling pathway(s) in SFN-induced cell cycle arrest and apoptosis and whether another chemopreventive agent selenium enhances the apoptosis potency of SFN. The results showed that SFN exposure for 24 h or longer significantly decreased the number of viable DU145 cells in a dose-dependent manner with an IC50 of asymptotically equal to 10 microM. The decreased cell number was associated with G2/M phase arrest and apoptotic cell death, with the latter being evidenced by caspase-mediated cleavage of poly(ADP-ribose) polymerase and increased release of histone-associated DNA fragments. A peptide inhibitor of caspase-8 completely blocked SFN-induced apoptosis and that for caspase-9 exerted a major protection; however, neither inhibitor attenuated SFN-induced G2/M arrest. Regarding potential mediators, SFN treatment induced a transient rise of reactive oxygen species (ROS) peaking within (1/2) h and the activation of JNK within 1 h but did not have any detectable effect on the phosphorylation of p38MAPK or ERK1/2 from 6 h to 24 h. Pretreatment of cells with N-acetylcysteine to enrich intracellular glutathione blocked SFN-induced ROS and apoptotic cell death. Inhibiting the JNK activity with a pharmacologic inhibitor SP600125 abolished the induction of G2/M arrest and apoptosis by SFN, whereas chemical inhibitors for p38MAPK and MEK1/2 did not have any modulating effect on SFN-induced apoptosis. Taken together, the data indicate that SFN decreased viable DU145 cell number in large part through the generation of ROS and JNK-mediated signaling to G2/M arrest and caspase-dependent apoptosis. Selenium in the form of inorganic sodium selenite salt or methylseleninic acid did not enhance SFN-induced apoptosis in this cell culture model.

Anticarcinogenic Agents↗

PubMed2005

Cambodian Phellinus linteus inhibits experimental metastasis of melanoma cells in mice via regulation of urokinase type plasminogen activator.

Phellinus linteus (PL) is a fungus mainly found in tropical America, Africa and Asian countries including Korea, Japan and China. PL has been traditionally used for the treatment of arthritis, liver damage and cancer. However, little was known on the biological activity and characterization of Phellinus species in Cambodia. Thus, in the present study, the anti-metastatic mechanism of aqueous extract of Cambodian Phellinus linteus (CPL) was evaluated. Cambodian mushroom was identified as a Phellinus species with 99% homology of Phellinus linteus by DNA sequence analysis and comparison by the National Center for Biotechnology Information. CPL did not exhibit any significant cytotoxicity against B16BL6 cells, invasive melanoma cells at 1 mg/ml. However, CPL inhibited platelet aggregation induced by B16BL6 cells and also disrupted the adhesion to gelatin and invasion of B16BL6 cells in a concentration dependent manner. Similarly, CPL dose-dependently inhibited the pulmonary metastatic colonies in C57BL/6 mice intravenously injected by B16BL6 cells up to 55.5% at a dose of 50 mg/kg compared with untreated control. CPL also down-regulated the expression of urokinase type plasminogen activator (uPA), one of key proteins associated with invasion and metastasis of tumor cells in a concentration dependent fashion, while CPL didn't significantly affect the expression of matrix metalloproteinase 2 (MMP-2) and tissue inhibitor of metalloproteinase 2 (TIMP-2) by reverse transcriptase-polymerase chain reaction (RT-PCR). Taken together, these findings indicate that Cambodian Phellinus linteus may inhibit metastasis at least partly via regulation of uPA associated with tumor cell induced platelet aggregation (TCIPA) and also suggest a further study for isolation of active ingredients and the involvement of adhesion molecule signaling pathway.

Agaricales↗