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Biomedical subjects

H R Kim

Publications and source records attributed to H R Kim.

At least 19 recordsLinked to original sources
PubMed2006

Prevalence of non-tuberculous mycobacteria in a hospital environment.

In recent years, non-tuberculous mycobacteria (NTM) have emerged as an important cause of opportunistic nosocomial infections but there is little known about the isolation and identification of NTM in Korea. The aim of this study was to assess the prevalence of NTM in the hospital environment and identify the species. A total of 150 samples were collected from different parts of the hospital. NTM were isolated and identified by restriction fragment length polymorphism analysis of the gene encoding rpoB and partial sequencing analysis of hsp65 and rpoB. In this study, 60 strains of NTM were isolated from 50 of the 150 samples. Half of the tap water samples (50 of 100) were positive for mycobacteria. An estimated 73.3% of the isolates were saprophytic, 21.7% were potentially pathogenic and 5% were unidentified. The presence of NTM in hospital tap water is not uncommon. Such water isolates might cause true nosocomial infection in immunocompromised patients, in addition to the risk of false-positive culture results.

Bacterial Proteins↗
PubMed2006

Placenta hominis protects osteoporosis in ovariectomized rats.

In China, Japan, and Korea, placenta hominis extracts (PHEs) are used clinically for the treatment of osteoporosis. The anti-osteoporotic effect of PHEs was studied. The trabecular bone area and thickness in OVX rats decreased by 50% from those in sham-operated rats; these decreases were completely inhibited by administration of PHEs for 7 weeks. Osteoclast numbers and the osteoblast surface were enhanced in OVX rats, but PHEs had no effect on these phenomena. Serum phosphorus and alkaline phosphatase in OVX rats increased compared to those in sham-operated rats, but the increases were not affected by the administration of PHEs. Thyroxine (T4) level was stimulated in OVX rats. The extracts inhibited the T4 level in the OVX rats. These results strongly suggest that PHEs be effective in preventing the development of bone loss induced by OVX in rats.

Animals↗
PubMed2005

Physical mapping and microsynteny of Brassica rapa ssp. pekinensis genome corresponding to a 222 kbp gene-rich region of Arabidopsis chromosome 4 and partially duplicated on chromosome 5.

We constructed a bacterial artificial chromosome (BAC) library, designated as KBrH, from high molecular weight genomic DNA of Brassica rapa ssp. pekinensis (Chinese cabbage). This library, which was constructed using HindIII-cleaved genomic DNA, consists of 56,592 clones with average insert size of 115 kbp. Using a partially duplicated DNA sequence of Arabidopsis, represented by 19 and 9 predicted genes on chromosome 4 and 5, respectively, and BAC clones from the KBrH library, we studied conservation and microsynteny corresponding to the Arabidopsis regions in B. rapa ssp. pekinensis. The BAC contigs assembled according to the Arabidopsis homoeologues revealed triplication and rearrangements in the Chinese cabbage. In general, collinearity of genes in the paralogous segments was maintained, but gene contents were highly variable with interstitial losses. We also used representative BAC clones, from the assembled contigs, as probes and hybridized them on mitotic (metaphase) and/or meiotic (leptotene/pachytene/metaphase I) chromosomes of Chinese cabbage using bicolor fluorescence in situ hybridization. The hybridization pattern physically identified the paralogous segments of the Arabidopsis homoeologues on B. rapa ssp. pekinensis chromosomes. The homoeologous segments corresponding to chromosome 4 of Arabidopsis were located on chromosomes 2, 8 and 7, whereas those of chromosome 5 were present on chromosomes 6, 1 and 4 of B. rapa ssp. pekinensis.

Arabidopsis↗
PubMed2005

Carbon monoxide and nitric oxide protect against tumor necrosis factor-alpha-induced apoptosis in osteoblasts: HO-1 is necessary to mediate the protection.

BACKGROUND: Carbon monoxide (CO) and nitric oxide (NO) each have unique roles for various inflammatory states, including inflammatory bone resorption. Although it is known that NO can induce the expression of the cytoprotective enzyme HO-1, there is no information as to whether the protective effect of CO requires NO production or whether CO must induce the expression of HO-1 to exert its functional effects. METHODS: Murine osteoblast cells, MC3T3E1 osteoblasts, were cultured for CO and NO-associated HO-1 experiments and were transfected with pcDNA 3, pcDNA 3-HO-1, control siRNA or HO-1 siRNA using Nucleofector. For cell death measurement, MTT and annexin V assays were used. We performed Western blotting to check the expressions of HO-1 and iNOs and measured the HO-1 enzyme activity. We also measured the amounts of nitrite and nitrate using Griess reagents. RESULTS: The increased expression of HO-1 is required for the protective effect of NO and a single treatment of CO can increase the expression of HO-1, and this is also important for the protective effect of CO in MC3T3E1 osteoblasts. CO as well as NO attenuates the TNF-alpha-induced apoptosis in osteoblasts. The anti-apoptotic effect of CO or NO is not mediated by cGMP, and CO has no effect on the release of NO. The inhibition of HO-1 with using the HO-1 inhibitor ZnPP or HO-1 siRNA resulted in a striking increase of apoptosis in the CO/TNF-alpha-treated cells. Furthermore, HO-1 overexpression showed resistance against the TNF-alpha-induced cytotoxicity in the MC3T3E1 osteoblasts. CONCLUSIONS: There is a need for HO-1 expression to mediate the protection provided by exogenous CO or NO in osteoblasts.

3T3 Cells↗
PubMed2005

p38 MAPK and NF-kappaB on IL-6 release in human gingival fibroblasts.

The induction of interleukin-6 (IL-6) using a proinflammatory cytokine (IL-1beta) was studied in human gingival fibroblasts (HGFs) in relation to p38 MAPK and NF-kappaB transcription factor. When added to HGFs, IL-1beta had a stimulatory effect on the production of IL-6, and this effect was significantly reduced by SB203580, a specific p38 MAPK inhibitor. In addition, the stimulation of IL-6 release also was reduced by the addition of pyrrolidine dithiocarbamate or NF-kappaB SN50, which has been reported as potent NF-kappaB inhibitor. Both the NF-kappaB inhibitors in the presence of SB203580 had more inhibitory effect on IL-6 release. IL-13 stimulated NF-kappaB binding affinity as well as p38 MAP kinase activation, leading to the release of IL-6. However, a specific inhibitor of p38 MAPK, SB203580, had no effect on the NF-kappaB activation, and both the NF-kappaB inhibitors failed to reduce the p38 MAPK activation in the IL-1beta-stimulated HGFs. These results strongly suggest that both p38 MAPK and NF-kappaB are required in IL-1beta-induced IL-6 synthesis and that these two IL-1beta-activated pathways can be primarily dissociated.

Dose-Response Relationship, Drug↗
PubMed2004

Inactivation of dispatched 1 by the chameleon mutation disrupts Hedgehog signalling in the zebrafish embryo.

Searches of zebrafish EST and whole genome shotgun sequence databases for sequences encoding the sterol-sensing domain (SSD) protein motif identified two sets of DNA sequences with significant homology to the Drosophila dispatched gene required for release of secreted Hedgehog protein. Using morpholino antisense oligonucleotides, we found that inhibition of one of these genes, designated Disp1, results in a phenotype similar to that of the "you-type" mutants, previously implicated in signalling by Hedgehog proteins in the zebrafish embryo. Injection of disp1 mRNA into embryos homozygous for one such mutation, chameleon (con) results in rescue of the mutant phenotype. Radiation hybrid mapping localised disp1 to the same region of LG20 to which the con mutation was mapped by meiotic recombination analysis. Sequence analysis of disp1 cDNA derived from homozygous con mutant embryos revealed that both mutant alleles are associated with premature termination codons in the disp1 coding sequence. By analysing the expression of markers of specific cell types in the neural tube, pancreas and myotome of con mutant and Disp1 morphant embryos, we conclude that Disp1 activity is essential for the secretion of lipid-modified Hh proteins from midline structures.

Amino Acid Sequence↗
PubMed2004

Prevention of bone loss in ovariectomized rats: the effect of Salvia miltiorrhiza extracts.

The preventive effect of Salvia miltiorrhiza extracts (SMEs) on the progress of bone loss induced by ovariectomy (OVX) was studied in rats. We measured body weight and bone histomorphometry in sham, OVX or SMEs-administered OVX rats. From light microscopic analyses, a porous or erosive appearances were observed on the surface of trabecular bone of tibia in OVX rats, whereas those of the same bone in sham rats and in SMEs-administered rats were composed of fine particles. The trabecular bone area and trabecular thickness in OVX rats decreased by 50% from those in sham rats, these decreases were completely inhibited by administration of SMEs for 7 weeks. In this study, the mechanical strength in femur neck was significantly enhanced by the treatment of SMEs for 7 weeks. In OVX rats, free T3 was normal in all cases, whereas free T4 was significantly increased. Although there was no difference between OVX and SMEs-administered rats in T3 level, we have found significant difference between them in T4 level. These results strongly suggest that SMEs are effective in preventing the development of bone loss induced by OVX in rats.

Alkaline Phosphatase↗
PubMed2004

Yuk-Hap-Tang induces apoptosis by intervening mn-SOD in human cervical carcinoma HeLa cells.

Yuk-Hap-Tang (YHT) induces cell death in human cervical carcinoma HeLa cells. Caspase-3, -6 and -9 were markedly activated in HeLa cells treated with YHT. The preferred substrate for caspase-3 cysteine protease, PARP, was cleaved to its 85-kDa cleavage product. YHT increased the amount of the anti-apoptotic protein, Bcl-2, and the pro-apoptotic protein, Bax. Although p53 has been reported to accumulate in cancer cells in response to anticancer agents, the p53 expression level was not changed in HeLa cells treated with YHT. Manganese (Mn)-TBAP, a mitochondria-specific SOD mimetic agent and NAC/GSH (N-acetyl cysteine/ reduced glutathione) reduced the YHT-induced cytotoxicity and decreased the number of the YHT-induced apoptotic cells. Furthermore, YHT reduced the expression of Mn-SOD protein and its activity in HeLa cells. The data demonstrate that YHT induces the apoptosis of human cervical carcinoma HeLa cells by intervening Mn-SOD.

Antioxidants↗
PubMed2003

Wax moth, Galleria mellonella, high density lipophorin receptor: alternative splicing, tissue-specific expression, and developmental regulation.

A lipophorin (Lp) receptor cDNA from the fat body of Galleria mellonella (Lepidoptera) was cloned and sequenced. This is the first result in this order, Lepidoptera. It showed the pattern of the VLDL receptor belonging to the LDL receptor family. Sequence homology with other Lp receptors in insects, Locusta migratoria and Aedes aegypti, was 70 and 61%, respectively and each domain was highly conserved. Polyclonal anti-Lp receptor antibody prepared against expressed Lp receptor fragment between ligand binding domain and EGF-precursor homology domain (R305-D549 of amino acid residues) specifically detected the Lp receptor. Through immuno-blotting, the Lp receptor of larval fat body has an approximate molecular mass of about 97 and 110 kDa under non-reducing and reducing conditions, respectively. This result was in agreement with that of the ligand-blotting. The variant Lp receptors were expressed in the fat body of G. mellonella; one is an Lp receptor which lacks 84 bp of O-linked sugar domain and the other is a full length form of the Lp receptor. Both forms were detected by the polyclonal anti-Lp receptor antibody. The Lp receptor from the fat body of G. mellonella was differently expressed depending on the tissue and the developmental stage with specific abundance in prepupal stage. A steroid hormone, 20-hydroxyecdysone (20-HE) plays a crucial role in insect development. With regards to this conception, day 1-2 last instar larvae were treated with 20-HE and drastic induction of the Lp receptor was observed 48 h after treatment. It was also observed that cholesterol caused an induction of the Lp receptor.

Amino Acid Sequence↗
PubMed2002

Inhibition of tumour necrosis factor-alpha secretion from rat astrocytes by Sesim-Tang.

Substance P (SP) can stimulate secretion of tumour necrosis factor-alpha (TNF-alpha) from astrocytes stimulated with lipopolysaccharide (LPS). In this study, we have examined whether an aqueous extract of Sesim-Tang inhibits the secretion of TNF-alpha from primary cultures of rat astrocytes. Sesim-Tang (10-1000 microg/mL) significantly inhibited the TNF-alpha secretion by astrocytes stimulated with LPS and SP. Interleukin-1 (IL-1) has been shown to elevate TNF-alpha secretion from LPS-stimulated astrocytes while having no effect on astrocytes in the absence of LPS. We therefore examined whether IL-1 mediated inhibition of TNF-alpha secretion from primary astrocytes by Sesim-Tang. Treatment with Sesim-Tang (10-1000 microg/mL) of astrocytes stimulated with both LPS and SP decreased IL-1 secretion significantly. Moreover, the secretion of TNF-alpha by LPS and SP in astrocytes was progressively inhibited with increasing amounts of IL-1 neutralizing antibody. Our results suggest that Sesim-Tang may inhibit TNF-alpha secretion by inhibiting IL-1 secretion and that Sesim-Tang has an antiinflammatory activity in the central nervous system.

Animals↗
PubMed2002

Internal hernia presenting as obstructive jaundice and acute pancreatitis.

We report the first case of obstructive jaundice and acute pancreatitis caused by herniation of the small bowel through the foramen of Winslow in a 45-year-old man. Abdominal computed tomography (CT) and magnetic resonance imaging (MRI) revealed dilated small-bowel loops positioned in the gastrohepatic space, dilatation of the gallbladder and both intrahepatic bile ducts, and mild swelling of the pancreas. A small-bowel series revealed a cluster of small-bowel loops in the mid-upper abdomen, with displacement of the stomach to the left. At laparotomy, there was an internal herniation of jejunal loop through the defect of gastrocolic ligament into the lesser sac and finally passing through the foramen of Winslow. The common bile duct was compressed externally by the herniated bowel and the pancreas was mildly swollen. To the best of our knowledge, these complications of internal hernia have not been reported previously.

Acute Disease↗
PubMed2002

ERK MAP Kinase is required in 1,25(OH)2D3-induced differentiation in human osteoblasts.

Expression of alkaline phosphatase(ALP)activity represents a key event during the differentiation processes of osteoblasts, and the level of ALP activity has been routinely used as a relative measure of differentiation stages of osteoblasts. In human osteoblasts, we showed that vitamin D3 analogue, 1,25(OH)2D3, had a stimulatory effect on ALP activity after 3 days, compared with control. The treatment of PD098059, an ERK MAP Kinase inhibitor, had a reducing effect on ALP activity, a differentiation marker in 1,25(OH)2D3-treated primary human osteoblasts. However, SB203580, a potent p38 MAP Kinase inhibitor, had no effect on the differentiation in this system. This indicates that ERK, not p38, is directly related to 1,25(OH)2D3-stimulated ALP activity in primary human osteoblasts. These results also show that the vitamin D3 analogue stimulates ERK1 activation in primary human osteoblasts. This finding provides one of signaling pathways for differentiation in primary human osteoblasts.

Alkaline Phosphatase↗
PubMed2001

Vibrio vulnificus cytolysin induces superoxide anion-initiated apoptotic signaling pathway in human ECV304 cells.

Previous studies showed that exposure to Vibrio vulnificus cytolysin (VVC) caused characteristic morphologic changes and dysfunction of vascular structures in lung. VVC showed cytotoxicity for mammalian cells in culture and acted as a vascular permeability factor. In this study, the underlying mechanisms of VVC-induced cytotoxicity was investigated on ECV304 cell, a human vascular endothelial cell line. When cells were exposed to 0.4 hemolytic units (HU) of VVC, consecutive apoptotic events were observed; the elevation of superoxide anion (O (-.)(2)), the release of cytochrome c, the activation of caspase-3, the cleavage of poly(ADP-ribose) polymerase, and the DNA fragmentation. The pretreatment with 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), O(-.) 2) scavenger, completely abolished O(-.)(2) levels and downstream apoptotic events. Moreover, pretreatment with cyclosporin A (CsA), a mitochondrial permeability transition inhibitor, was capable of attenuating O(-.)(2)-mediated cytochrome c release and caspase-3 activation, and consequent apoptosis. Apoptosis, as demonstrated by oligonucleosomal DNA fragmentation and fluorescence microscopy, was induced 24 h after VVC treatment, which was also prevented by caspase-3 inhibitor, Ac-DEVD-CHO. Caspase-1 inhibitor, Ac-YVAD-CHO, did not protect ECV 304 cells from apoptosis. These results suggest a scenario where VVC-induced apoptosis is triggered by the generation of O(-.)(2), release of cytochrome c from mitochondria, activation of caspase-3, degradation of poly(ADP-ribose) polymerase, and DNA fragmentation. The induction of apoptosis in endothelial cells by VVC may provide a pivotal mechanism for understanding the pathophysiology of septicemia.

Anions↗
PubMed2001

DNA-mediated immunization of glycoprotein 350 of Epstein-Barr virus induces the effective humoral and cellular immune responses against the antigen.

Epstein-Barr virus (EBV) is a human pathogen that is involved in numerous diseases and tumors. Since the EBV infection occurs in the early ages of life, and most of the population is subsequently exposed to EBV, the conventional method of vaccination to induce the prophylactic immunity cannot be considered effective in coping with the virus infection. In this study, we tested whether the injection of a plasmid vector that contained the gene for glycoprotein 350 (gp350), which had been identified as a ligand for virus' adsorption and a target for virus neutralizing antibodies, could induce effective immune responses against the antigen. As a result, the injection of the constructed plasmid vector into mice induced the production of gp350-specific antibodies. A major isotype of the gp350-specific antibodies was IgG1. The antibodies efficiently mediated the antibody-dependent cellular cytotoxicity against the cells expressing the gp350 antigen. In addition, the injection of the constructed plasmid vector stimulated the precursor T cell population that was specific to the gp350 antigen. In addition, gp350-specific cytotoxic T lymphocytes were efficiently stimulated by the injection of the constructed plasmid vector. These results suggested that the injection of the plasmid vector, containing the gp350 gene of Epstein-Barr virus, could be one of the most effective ways to induce both prophylactic and therapeutic vaccinations against the virus infection.

Animals↗
PubMed2001

Cross-linking of MHC class II molecules with anti-MHC class II antibody or epitope peptide prevents resting B lymphocyte differentiation by inhibiting NF-kappaB-dependent gene expression.

To understand the mechanism(s) involved in anti-MHC class II antibody-mediated inhibition of B lymphocyte differentiation, we investigated the influence of anti-MHC class II antibody treatment on the gene expression of IL-6 in resting B lymphocytes, which had been known to be one of the most important cytokines involved in B cell physiology. The level of the IL-6 mRNA expression in the LPS-stimulated resting B cells was remarkably reduced by treatment of the corresponding anti-MHC class II antibodies. The inhibition was exerted in haplotype-specific and dose-dependent manners. Similarly, MHC class II-restricted epitope peptides, when applied as a dimer form, revealed haplotype-specific and dose-dependent inhibitory effects on the IL-6 gene expression by the LPS-stimulated B cells. In addition, treatment of the anti-MHC class II antibody and MHC class II-restricted epitope peptide inhibited, in haplotype-specific and dose-dependent manners, the activation of NF-kappaB, which had been known to be one of the critical transcription factors involved in the IL-6 gene expression. Interestingly, however, exogenous addition of the recombinant IL-6 did not reverse this inhibitory effect by the anti-MHC class II antibody. These results suggest that conjugation of the MHC class II molecules by the anti-MHC class II antibody inhibited B cell differentiation, possibly through the interruption of signaling pathways leading to the IL-6 gene expression via NF-kappaB activation in B lymphocytes.

Animals↗
PubMed2001

Characterization of a novel allele of glucose oxidase from a Korean wild type strain of Aspergillus niger.

We have identified a novel allele of the glucose oxidase (GO, EC1.1.3.4) gene (GO) from a Korean wild type strain of Aspergillus niger, ACMO4, with an increased GO activity in culture filtrate. Southern blot analyses of GO from ACMO4 (GO-ACMO4) revealed that the gene was present as a single copy in the genome of A. niger. However, its sequence differs from that of GO from A. niger ATCC 9029 (GO-ATCC9029). GO-ACMO4 appears to be a functional gene based on the fact that it is enzymatically active when heterologously expressed in yeast. Sequence comparisons of the coding region of GO-ACMO4 revealed 16 nucleotide changes that resulted in four amino acid substitutions; T432D, G517D, G530S, and Q542R. The GO proteins from both ATCC 9029 and ACMO4 were heterologously expressed, purified, and compared biochemically. The two enzymes showed no difference in their apparent Km value for glucose (30 mM), but the Vmax of GO-ACMO4 (515.6 unit/mg) was 10% higher than that of GO-ATCC 9029, resulting in a 10% higher specific activity.

Alleles↗
PubMed2001

Both platelet-derived growth factor receptor (PDGFR)-alpha and PDGFR-beta promote murine fibroblast cell migration.

Cell motility plays a critical role for many physiological and pathological processes including wound healing, fibrosis, angiogenesis, and tumor metastasis. Platelet-derived growth factor (PDGF) is among the most potent stimuli for mesenchymal cell migration. The PDGF B-chain homodimer PDGF BB activates both alpha- and beta-receptor subunits (alpha-PDGFR and beta-PDGFR), and promotes cell migration in many cell types including fibroblasts and smooth muscle cells. PDGF-A chain homodimer PDGF AA activates alpha-PDGFR only, and its role for cell migration is still debatable. PDGF BB, but not PDGF AA, induces smooth muscle cell migration. Interestingly, alpha-PDGFR was shown to antagonize beta-PDGFR-induced smooth muscle cell migration. In the present study, we investigated the role of alpha-PDGFR and beta-PDGFR in PDGF-mediated cell migration of murine fibroblasts (NIH 3T3). Unlike smooth muscle cells, both PDGF AA and PDGF BB promoted NIH 3T3 cell migration. The effect of PDGF BB activation of beta-PDGFR alone for cell migration was examined using previously established NIH 3T3 clones in which alpha-PDGFR signaling is inhibited by a dominant-negative alpha-PDGFR, or an antisense construct of alpha-PDGFR. PDGF BB activation of beta-PDGFR alone was sufficient to induce cell migration, but the efficiency was significantly lower compared to PDGF activation of both receptors. These results showed that both alpha- and beta-PDGFRs promote fibroblast cell migration and their effects are additive. Taken together, we propose that cell-type specific alpha-PDGFR signaling is critical for regulation of mesenchymal cell migration in response to PDGF isoform, whereas beta-PDGFR mainly promotes cell migration.

3T3 Cells↗