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Biomedical subjects

Young-Ho Kim

Publications and source records attributed to Young-Ho Kim.

At least 73 records · Page 4Linked to original sources
PubMed2004

Inhibition of trypsin-induced mast cell activation by water fraction of Lonicera japonica.

Lonicera japonica Thunb.(Caprifoliaceae) has long been known as an anti-inflammatory. In the present study, the effect of water fraction of Lonicera japonica (LJ) on trypsin-induced mast cell activation was examined. HMC-1 cells were stimulated with trypsin (100 nM) in the presence or absence of LJ (10, 100, and 1000 microg/mL). TNF-alpha and tryptase production were measured by enzyme-linked immunosorbent assay (ELISA) and reverse transcription-PCR. Extracellular signal-regulated kinase (ERK) phosphorylation was assessed by Western blot. Trypsin activity was measured by using Bz-DL-Arg-p-nitroanilide (BAPNA) as substrate. LJ (10, 100, and 1000 microg/mL) inhibited TNF-alpha secretion in a dose-dependent manner. LJ (10, 100, and 1000 microg/mL) also inhibited TNF-alpha and tryptase mRNA expression in trypsin-stimulated HMC-1. Furthermore, LJ inhibited trypsin-induced ERK phosphorylation. However, LJ did not affect the trypsin activity even 1000 microg/mL. These results indicate that LJ may inhibit trypsin-induced mast cell activation through the inhibition of ERK phosphorylation than the inhibition of trypsin activity.

Cell Line, Tumor↗
PubMed2004

Apoptosis inducing effects of 6-methoxydihydrosanguinarine in HT29 colon carcinoma cells.

6-methoxydihydrosanguinarine (6ME), a benzophenanthridine alkaloid derived from the methanol extracts of Hylomecon hylomeconoides, showed a dose-dependent effect at 1-10 microM on causing apoptotic cell death in HT29 colon carcinoma cells (IC50 = 5.0+/-0.2 microM). Treatment of HT-29 cells with 6ME resulted in the formation of internucleosomal DNA fragmentation. Treatment of the cells with 6ME caused activation of caspase-3, -8 and 9 protease and subsequent proteolytic cleavage of poly(ADP-ribose)polymerase. 6ME increased the expression of p53 and Bax and decreased the expression of Bid. These results indicate that p53 and proapoptotic Bcl-2 family proteins might participate in the antiproliferative activity of 6ME in HT29 cells.

Alkaloids↗
PubMed2004

Acanthoic acid inhibits IL-8 production via MAPKs and NF-kappaB in a TNF-alpha-stimulated human intestinal epithelial cell line.

BACKGROUND: Intestinal epithelial cells (IECs) can produce cytokines and chemokines that play an important role in the mucosal immune response. Regulation of this production is important to prevent inflammatory tissue damage. The root and stem barks of Acanthopanax species have been used as a tonic and sedative as well as in the treatment of rheumatism and diabetes. The aim of this study was to examine the inhibitory effect of acanthoic acid isolated from Acanthopanax koreanum (Araliaceae), on IL-8 production via mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-kappaB) in TNF-alpha-stimulated human colon epithelial cells. METHODS: HT29 cells were stimulated with TNF-alpha in the presence or absence of acanthoic acid. IL-8 production was measured by enzyme-linked immunosorbent assay (ELISA) and reverse transcription-PCR (RT-PCR). MAPK activation and IkappaB/NF-kappaB expression were assessed by Western blot analysis. NF-kappaB activation was determined using immunofluorescence localization and electrophoretic mobility shift assay (EMSA). RESULTS: Acanthoic acid suppressed TNF-alpha-induced IL-8 production in a dose-dependent manner. Furthermore, acanthoic acid inhibited TNF-alpha-induced MAPKs (p38, JNK1/2, and ERK1/2) activation, IkappaB degradation, NF-kappaB nuclear translocation, and NF-kappaB/DNA binding activity. CONCLUSION: Acanthoic acid might inhibit TNF-alpha-mediated IL-8 production by blocking in both the MAPKs and NF-kappaB pathways in HT29 cells.

Cell Line↗
PubMed2004

Deletion of a hypoviral-regulated cppk1 gene in a chestnut blight fungus, Cryphonectria parasitica, results in microcolonies.

The cppk1 gene encodes a Ser/Thr protein kinase of Cryphonectria parasitica and is transcriptionally up-regulated by the presence of hypovirus CHV1-EP713. A cppk1-null mutant was constructed to determine the function of cppk1. The cppk1-null mutant was initially isolated as a heterokaryotic form containing both wild-type and cppk1-deleted nuclei. The pure cppk1-null homokaryon was obtained by the single spore isolation of the heterokaryon. While the parental heterokaryon appeared normal, the pure cppk1-null mutant exhibited dramatic changes in colony morphology. It showed characteristics of microcolonial growth. The functional complementation, restoration of filamentous growth, of the cppk1-null mutant using a wild-type cppk1 gene indicated that the phenotypic changes were due to the disruption of cppk1. Neither sporulation nor hyphal differentiation into feeding hyphae, a mycelial mat, or aerial hyphae was observed in the cppk1-null mutant. Instead of bright yellow, dark brown pigmentation appeared as the culture grew. Hyphae were shortened and hyperbranched with globose to bulbose cells. Electron microscopy revealed the presence of intrahyphal hyphae, the most striking ultrastructural change. Subtle changes in the expression of CpPK1 resulted in abnormalities in colony morphology and pigmentation, which indicated that cppk1 is important for coordinating growth with development and maintaining cell wall integrity.

Ascomycota↗
PubMed2004

Korean adolescents' exercise behavior and its relationship with psychological variables based on stages of change model.

PURPOSE: To examine the exercise behavior of Korean adolescents, reveal the differences in self-efficacy and decision balance by the stages of exercise behavior, and identify the relationship between exercise behavior and psychological variables. METHODS: A total of 671 adolescents randomly selected from junior high and high schools in Seoul were surveyed. Three Korean-version questionnaires were used to identify the stage of exercise behavior and psychological attributes of adolescents: Stage of Exercise Behavior Change Questionnaire, Decision Balance Scale for Exercise, and Exercise Self-efficacy Scale. Data were analyzed by frequency analysis, chi(2) test, MANOVA, correlation analysis, and regression analysis. RESULTS: The exercise pattern of Korean adolescents was different by each stage of exercise behavior: precontemplation (17.5%), contemplation (16.6%), preparation (20.4%), action (28.3%), and maintenance (17.2%). Significant differences in exercise behavior distribution emerged as a function of gender and age. In addition, exercise efficacy, exercise benefits and exercise barriers differentiated across the stages of exercise behavior. Furthermore, the findings revealed that adolescents' exercise behavior was significantly correlated with the selected psychological variables, and that psychological variables had a statistically significant impact on the exercise behavior. CONCLUSION: This study provides information about relatively unstudied Korean adolescents and has the potential to influence the development of better exercise interventions and health promotion programs for adolescents.

Adolescent↗
PubMed2004

Psychological constructs to predicting smoking behavior among Korean secondary school students.

BACKGROUND: Current research on cigarette smoking has largely been focused on identifying the relationship between psychological attributes and the onset or initiation of smoking behavior. Few data are available on the psychological predictors of smoking behavior among Korean adolescents. This study examined the prevalence of smoking behavior among Korean adolescents, revealed factors affecting their smoking behavior, and identified the relationship between smoking behavior and psychological variables. METHODS: Four Korean-version questionnaires were used to assess adolescents' smoking behavior and their psychological attributes: Smoking Habit Scale, Multidimensional Health Locus of Scale, Self-efficacy Scale, and Self-esteem Scale. Frequency, Chi-square, ANOVA, correlation, and regression analyses were performed to analyze the data obtained in the study. RESULTS: The results indicate that smoking problem in the Korean adolescents is a crucial factor that might adversely affect their overall health. Forty-three percent of adolescents responded that they had smoked a cigarette in their lifetime and 26% are current smokers. Male adolescents were more likely to smoke in their lifetime and have currently smoked a cigarette than females. The adolescents aged 17-18 years had smoked more cigarette than those in other age groups. Among the five psychological variables, IHLC and self-efficacy significantly differentiated adolescents at different smoking status. Furthermore, IHLC, self-esteem, and self-efficacy were significantly correlated with smoking behavior and those psychological constructs had a significant linear relation to account for smoking behavior. CONCLUSIONS: Psychological variables have a meaningful influence on smoking behavior of adolescents.

Adolescent↗
PubMed2004

Healing rate of EMR-induced ulcer in relation to the duration of treatment with omeprazole.

BACKGROUND: Although EMR-induced ulcers heal faster and recur less often than noniatrogenic gastric ulcers, there is no consensus regarding the duration of therapy for these ulcers. This study prospectively evaluated healing of EMR-induced ulcers according to the duration of omeprazole therapy. METHODS: A total of 69 patients were randomly assigned, after EMR, to treatment with omeprazole (20 mg per day) for 7 days (1-week group) or with omeprazole (20 mg per day) for 28 days (4-week group). Four weeks after EMR, ulcer size and stage were compared with those of the initial EMR-induced ulcer. Each patient kept a daily diary of drugs consumed and ulcer-related symptoms during the 4-week period after EMR. RESULTS: Thirty-four patients were randomized to the 4-week group, and 26 were randomized to the 1-week group. No significant differences were observed between the two groups at 4 weeks after EMR in terms of ulcer reduction ratio (p=0.29) or stage (p=0.11). In addition, no difference was observed between the two groups with respect to ulcer-related symptoms or use of additional gastric-coating medication (p=0.48). CONCLUSIONS: For EMR-induced ulcer, treatment with omeprazole for 1 week is equivalent to treatment for 4 weeks. Short-term therapy with omeprazole can be considered for EMR-induced ulcer.

Adenoma↗
PubMed2004

Korean medicinal plant extracts exhibit antiviral potency against viral hepatitis.

OBJECTIVES: Investigation of natural ethnopharmacologic extracts exhibiting antiviral potential may lead to the discovery of new therapeutics for the treatment of chronic viral hepatitis infections. Traditional Korean medicinal herbs have been identified that exhibit potency against hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. Research on the antiviral potential of naturally derived extracts is facilitated through the use of appropriate animal and liver cell culture models for these hepatotrophic pathogens. Objectives of this study were to demonstrate antiviral activity of an aqueous extract of herbal formulation KYH-1 in surrogate in vitro assays for HBV and HCV and identify mechanisms of action. METHODS: Antiviral potency of KYH-1 was measured in tissue culture systems that support replication of the woodchuck hepatitis virus (WHV), and the bovine viral diarrhea virus (BVDV). These assays serve as surrogate models for HBV and HCV, respectively. A recombinant HBV polymerase gene expression assay was used to define a molecular target. RESULTS: KYH-1 exhibited potent antiviral activity against WHV and to a lesser extent against BVDV. KYH-1 and its constituent components inhibited HBV polymerase priming in vitro. Additionally, KYH-1 suppressed HBV replication in a human hepatoblastoma cell line. CONCLUSION: Evaluation of naturally derived products for antiviral activity against HBV and HCV in standardized surrogate assays provides a scientific basis for potential use as complementary or alternative medicines. This study provides significant results justifying preclinical evaluation of KYH-1 as an antiviral therapy for HBV infections.

Antiviral Agents↗
PubMed2004

Influence of p53 and p21Waf1 expression on G2/M phase arrest of colorectal carcinoma HCT116 cells to proteasome inhibitors.

Ubiquitin-mediated protein degradation in vertebrates has been implicated in cell cycle control. In this report we explored the effects of proteasome inhibitors (MG132, lactacystin and ALLN) on cell cycle distribution. Colorectal carcinoma HCT116 cells were treated with proteasome inhibitor MG132. The results showed that MG132 inhibited cell proliferation in a dose-dependent manner. MG132 arrested HCT116 cells at G2/M phase, which was associated with drug-induced blockade of p53 degradation and/or induction of p53-related gene expression along with the accumulation of cyclin B, cyclin A and p21. MG132 treated HCT116 (wild-type) had a similar cell cycle distribution as the MG132 treated HCT116 (p53-/-) and HCT116 (p21-/-) cells, suggesting that p53 and p21 may not be essential for MG132-induced G2/M phase arrest. The release experiments from nocodazole-induced mitotic phase cells indicated that MG132 inhibits the proliferation of HCT116 cells via arrest in the G2 phase. In addition, when HCT116 cells were exposed to combination of sodium butyrate and MG132 enhanced cell growth inhibition and induction of apoptosis were observed.

Acetylcysteine↗
PubMed2004

The impact of Helicobacter pylori infection on coronary heart disease in a Korean population.

BACKGROUND/AIMS: Although several studies have claimed that Helicobacter pylori (H. pylori) infection is related to cardiovascular disease, it is still uncertain whether it is related to the acute process or the chronic inflammatory atherosclerotic changes. The aim of our study was to confirm the impact of active H. pylori infection on coronary heart disease, acute inflammatory factors, and the coagulation factors. METHODS: A total of 94 patients completed questionnaires about occupation, smoking, past medical history, and socio-economic status. The serum of the subjects was drawn for a low density lipoprotein test, white blood cell count, C reactive protein, fibrinogen, homocysteine, prothrombin time, activated partial thrombin time, plasminogen activator inhibitor type-1, and tissue-type plasminogen test. All of the subjects underwent a coronary angiography and an upper gastrointestinal endoscopy for the diagnosis of coronary heart disease and H. pylori infection, respectively. RESULTS: There was no significant difference in acute inflammatory factors, coagulation factors, atheromatous burden score, and Jeopardy score between the H. pylori-infected group and non-infected group. Odds ratio of H. pylori infection on coronary heart disease was 2.59 (95% CI, 0.80-6.17), but it diminished below 1.0 (95% CI, 0.14-1.36) after adjusting for conventional risk factors such as age, gender, diabetes, hypertension, smoking, body mass index and socio-economic status. CONCLUSIONS: H. pylori infection is not an independent risk factor for coronary heart disease, and it does not alter the coagulation system or evoke the systemic inflammatory response.

Aged↗
PubMed2004

Cyclin E, p27 and mutant p53 do not predict the prognosis in AJCC stage II colorectal carcinomas.

BACKGROUND/AIMS: Carcinogenesis is characterized by the abnormal regulation of cell cycle. The abnormal expression of the regulators of cell cycle may be related to the prognosis. Since the clinical significance of the expression of the three proteins in colorectal carcinomas is still controversial, we evaluated the prognostic value of the expression of cyclin E, p27 and mutant p53 in stage II colorectal cancer. METHODS: The expression levels of cyclin E, p27 and mutant p53 proteins in 41 patients with stage II colorectal carcinomas were analyzed by immunohistochemistry. RESULTS: In the univariate analysis, the level of CEA at diagnosis was associated with disease relapse. In the multivariate analysis, the clinicopathological variables such as age, gender, site of primary tumor, tumor size, state of tumor differentiation and preoperative plasma CEA level were not associated with disease relapse. When Kaplan-Meier survival curves were constructed to determine the prognosis, cyclin E, p27 and mutant p53 expressions did not predict poor prognosis. CONCLUSIONS: Our results suggested that the expression of cyclin E, p27 and mutant p53 proteins did not predict the clinical outcome in the stage II colorectal carcinomas.

Adenocarcinoma↗
PubMed2003

Vocal analysis after vertical partial laryngectomy.

It is generally believed that a reconstruction of the glottic region after a vertical partial laryngectomy (VPL) can improve the glottic and supraglottic function. However, there is a paucity of reports on secondary healing without a glottic reconstruction after a VPL. The aim of this study was to obtain objective phonatory data after a VPL without a glottic reconstruction. From 1993 to 2001, 13 patients, who had been treated with VPL without a glottic reconstruction, were enrolled in this study. Patients with a postoperative follow up of less than 12 months were excluded. Seven lesions were classified as T1 glottic cancer and six as T2 glottic cancer- standard VPL (11 cases) and frontolateral VPL (2 cases). Acoustic ((fundamental frequency, Fo), jitter, shimmer, the noise to harmonic ratio (NHR)), aerodynamic (maximal phonation time (MPT), mean flow rate (MFR)) analysis and videostroboscopy were performed to evaluate the voice. There were significant differences in the Fo, jitter, shimmer, NHR, MPT and MFR between the VPL group and normal control group. In videostroboscopy, the following tendencies were observed in many cases: incomplete glottic closure, a decreased and irregular mucosal wave and amplitude, supraglottic voicing, abnormal arytenoid movement and anterior commissure blunting. Objective phonatory data after VPL without a glottic reconstruction was obtained. The voice quality after a VPL without a glottic reconstruction was somewhat unsatisfactory. A further comparison with other different surgical techniques of a VPL would help determine a better way of improving the voice quality in these patients.

Adult↗
PubMed2003

Bcl-2 overexpression prevents daunorubicin-induced apoptosis through inhibition of XIAP and Akt degradation.

Daunorubicin (DNR) induces apoptosis in the human myeloid leukemia cells by activation of neutral sphingomyelinease and ceramide production. In the present study, we determined the effect of the antiapoptosis protein Bcl-2 on caspase-3 activation, phospholipase C-gamma 1 (PLC-gamma 1) degradation and cytochrome c release during the DNR-induced apoptosis. Treatment with 3 microM DNR for 12 hr produced morphological features of apoptosis and DNA fragmentation in U937 cells, which was associated with caspase-3 activation and PLC-gamma 1 degradation. Induction of apoptosis was also accompanied by release of cytochrome c, down-regulation of X-linked inhibitor of apoptosis protein (XIAP), and inactivation of Akt, which was blocked by the pan-caspase inhibitor z-VAD-fmk. DNR-induced caspase-3 activation, PLC-gamma 1 degradation and apoptosis were significantly attenuated in Bcl-2 overexpressing U937/Bcl-2 cells. Ectopic expression of Bcl-2 appeared to inhibit DNR-induced apoptosis by interfering with inhibition of XIAP and Akt degradation.

Antineoplastic Agents↗
PubMed2003

Arisostatins A induces apoptosis through the activation of caspase-3 and reactive oxygen species generation in AMC-HN-4 cells.

A microbial secondary metabolite, arisostatins A (As-A), was originally discovered as a substance carrying the antibiotic activity against Gram-positive bacteria and shown to possess potent anti-tumor properties. The mechanism by which arisostatins A initiates apoptosis remains poorly understood. In the present report we investigated the effect of arisostatins A on activation of the apoptotic pathway in HN-4 cells. Arisostatins A was shown to be responsible for the inhibition of HN-4 cell growth by inducing apoptosis. Treatment with 4 microM arisostatins A for 24h produced morphological features of apoptosis and DNA fragmentation in HN-4 cells. Arisostatins A caused dose-dependent apoptosis and DNA fragmentation of HN-4 cells used as a model. Treatment with caspase inhibitor significantly reduced the arisostatins A-induced caspase 3 activation. In addition, arisostatins A-induced apoptosis was associated with the generation of reactive oxygen species (ROS), which was prevented by an antioxidant NAC (N-acetyl-cysteine). These data indicate that cytotoxic effect of arisostatins A on HN-4 cells is attributable to the induced apoptosis and that arisostatins A-induced apoptosis is mediated by caspase-3 activation pathway, loss of mitochondrial transmembrane potential (DeltaPsi(m)), and release of cytochrome c into cytosol.

Aminoglycosides↗
PubMed2003

Immunosuppressant PG490 (triptolide) induces apoptosis through the activation of caspase-3 and down-regulation of XIAP in U937 cells.

PG490 (triptolide) is a natural, biologically active compound extracted from Chinese herb Tripterygium wilfordii. It possesses potent anti-inflammatory and immunosuppressive properties. The mechanism by which triptolide initiates apoptosis remains poorly understood. In the present report, we investigated the effect of triptolide on the apoptotic pathway in U937 human promonocytic cells. We show that triptolide inhibits U937 cells growth by inducing apoptosis. Following treatment of U937 cells with 25 nM triptoride for 24 hr, morphological features of apoptosis and DNA fragmentation were observed. Caspase inhibitors significantly reduced triptolide-induced caspase-3 activation. In addition, apoptosis triggered by triptolide was not associated with the generation of reactive oxygen species, which was not affected by the antioxidant N-acetylcysteine (NAC). The data collectively indicate that the cytotoxic effect of triptolide in U937 cells is attributable to apoptosis mediated by the caspase-3 activation pathway that may be associated with XIAP down-regulation.

Apoptosis↗
PubMed2003

N-(3-acyloxy-2-benzylpropyl)-N'-[4-(methylsulfonylamino)benzyl]thiourea analogues: novel potent and high affinity antagonists and partial antagonists of the vanilloid receptor.

Isosteric replacement of the phenolic hydroxyl group in potent vanilloid receptor (VR1) agonists with the alkylsulfonamido group provides a series of compounds which are effective antagonists to the action of the capsaicin on rat VR1 heterologously expressed in Chinese hamster ovary (CHO) cells. In particular, compound 61, N-[2-(3,4-dimethylbenzyl)-3-pivaloyloxypropyl]-N'-[3-fluoro-4-(methylsulfonylamino)benzyl]thiourea was a full antagonist against capsaicin, displayed a K(i) value of 7.8 nM (compared to 520 nM for capsazepine and 4 nM for 5-iodoRTX), and showed excellent analgesic activity in mice. Structure-activity analysis of the influence of modifications in the A- and C-regions of 4-methylsulfonamide ligands on VR1 agonism/antagonism indicated that 3-fluoro substitution in the A-region and a 4-tert-butylbenzyl moiety in the C-region favored antagonism, whereas a 3-methoxy group in the A-region and 3-acyloxy-2-benzylpropyl moieties in the C-region favored agonism.

Analgesics↗
PubMed2003

Dykellic acid inhibits phorbol myristate acetate-induced matrix metalloproteinase-9 expression by inhibiting nuclear factor kappa B transcriptional activity.

Proteolytic degradation of the extracellular matrix and tumor metastasis correlate with expression of endopeptidases known as matrix metalloproteinases (MMPs). Expression of MMPs is regulated by cytokines and signal transduction pathways, including those activated by phorbol myristate acetate. We found that dykellic acid, a fungal metabolite, significantly inhibits the phorbol myristate acetate-induced increase in MMP-9 expression and activity. These effects of dykellic acid are time- and dose-dependent, and correlate with decreased MMP-9 promoter activity and mRNA expression. Whereas this compound does not affect DNA binding activity of nuclear factor kappa B (NF kappa B), dykellic acid does inhibit transactivation of NF kappa B. These data demonstrate a role for NF kappa B in the regulation of MMP-9 expression and the ability of dykellic acid to suppress this action of NF kappa B.

Enzyme Induction↗