Biomedical subjects

Y R Kim

Publications and source records attributed to Y R Kim.

At least 19 recordsLinked to original sources

PubMed2006

Immunoproteomic analysis of capsulate and non-capsulate strains of Lactococcus garvieae.

A comparative immunoproteomic study was carried out to investigate the immunogenicity of capsulate (KG9408) and non-capsulate (NSS9310) strains of Lactococcus garvieae. Immunoblot assays, following two-dimensional gel electrophoresis (2-DE) for L. garvieae strains, revealed a significant difference between anti-capsulate and anti-non-capsulate rabbit sera with respect to the number and antigenicity of antigenic spots. Anti-capsulate and anti-non-capsulate rabbit sera reacted with an average of 72 and 127 antigenic spots, respectively. The strong reaction of anti-non-capsulate sera with elongation factor (EF)-G and -Tu, and GMP synthase, of the L. garvieae strains identifies these as specific major antigens. This study clearly demonstrates the differences in 2-DE immunoblot profiles between the capsulate and non-capsulate strains of L. garvieae. These differences may be the reason for variations in immunogenicity between capsulate and non-capsulate strains. Glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, arginine deaminase and ornithine carbamoyltransferase were identified from the 2-DE immunoblot profiles of both strains. Therefore, these common antigens are potential markers for the development of vaccines against L. garvieae, irrespective of strain. Immunoproteomics, a powerful tool for studying antigens at the proteomic level, allowed a comparative investigation of the immunogenicity of capsulate and non-capsulate strains of L. garvieae for vaccine development.

Animals↗

PubMed2006

Therapeutic use of granulocyte-colony stimulating factor could conceal residual malignant cells in patients with AML1/ETO+ acute myelogenous leukemia.

We have experienced a number of cases of AML1/ETO+ acute myelogenous leukemia that showed remission based on bone marrow (BM) morphological criteria, but that revealed clonal abnormalities in most cells by fluorescence in situ hybridization (FISH). Interestingly, most of these cases had AML with AML1/ETO rearrangement. The malignant cells were differentiated and considered mature cells after granulocyte-colony stimulating factor (G-CSF) treatment. To clarify the possible mechanisms underlying this phenomenon, we investigated the expression levels of G-CSFR in AML cells with AML1/ETO rearrangement by flow cytometry and real-time polymerase chain reaction (PCR). The number of AML1/ETO+ cells expressing G-CSFR at baseline was significantly higher than that of AML1/ETO- AML cells (2673 vs 522). In addition, the G-CSFR gene was more highly expressed in AML1/ETO+ cells than in AML1/ETO- cells by real-time PCR. This study reveals that cases showing remission after treatment with G-CSF mostly had leukemia with AML1/ETO rearrangement. This finding might be explained by the higher expression of G-CSF receptor in AML1/ETO+ cells than in AML1/ETO- cells. We recommend that remission should be confirmed by FISH, because malignant clones can be differentiated and masked in morphological examination or chromosome test, especially for AML with AML1/ETO rearrangement.

Adolescent↗

PubMed2004

Measurement of tumor interstitial volume fraction: method and implication for drug delivery.

It is important to evaluate the tumor interstitial volume fraction that is accessible for drug accumulation during the distribution phase in order to determine the potential efficacy of cancer chemotherapy. In this study, we performed simulations of magnetic resonance imaging (MRI) signal intensity using a two-compartment tissue model for quantitative analyses of absolute interstitial volume measurements while we experimentally characterized a mouse tumor model with a dual MR contrast-agent method. Previously, consecutive intravenous injections of a strictly intravascular T1 contrast agent followed by an extravasating agent were used as a strategy for the quantification of both relative blood volume (Rel_BV) and relative interstitial volume (Rel_ITST) (Weissleder et al. Eur J Cancer 1998;34:1448-1454; Bogdanov et al. Neoplasia 1991;1:438-435). In the current study, we demonstrate that this approach can be further improved, and that it enables one to accurately evaluate both relative and absolute interstitial volumes. The animal data indicated that a significant difference exists between the absolute interstitial volume fractions of subcutaneously implanted MDA PCa 2b tumor and skeletal muscle tissue (27.5 +/- 9.1% and 15.9 +/- 0.7%, respectively (P < 0.05)), while only a minor difference was found for the absolute blood volumes (Abs_BV) (Kim et al. Magn Reson Med 2002;47:1110-1120) of these tissues.

Animals↗

PubMed2004

Protein 4.1 deficiency and deletion of chromosome 20q are associated with acquired elliptocytosis in myelodysplastic syndrome.

We report a case of myelodysplastic syndrome (MDS), associated with prominent elliptocytosis. A 66-year-old male presented with peripheral pancytopenia, and was diagnosed with MDS [refractory anaemia (RA)]. Apart from marked elliptocytosis, dyshaematopoietic features were not evident in his peripheral blood or hypercellular bone marrow. After 18 months, he had progressed to RA with excess blasts in transformation. Analysis of red blood cell membrane proteins by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed a reduced quantity of protein 4.1 (30% of control). Deletion of chromosome 20q was identified by conventional cytogenetic analysis and fluorescence in situ hybridization. Marked elliptocytosis, persistent for more than 17 months, decreased strikingly after chemotherapy with idarubicin and Ara-C. These findings suggest that acquired elliptocytosis occurred as an unusual morphological feature of MDS, associated with abnormalities of protein 4.1 and chromosome 20q.

Aged↗

PubMed2002

Water exchange and inflow affect the accuracy of T1-GRE blood volume measurements: implications for the evaluation of tumor angiogenesis.

The goal of this study was to determine the degree to which vascular water exchange and blood flowing into an imaging slice affect the accuracy of blood volume measurements of brain and tumor tissue when using intravascular T(1) contrast agents. The study was performed using 2D and 3D gradient-echo imaging sequences, since these are two of the most commonly used MRI methods used to evaluate tissue blood volume fraction. Computer simulations were performed and measurements made in a rat 9L gliosarcoma brain tumor model. The computer simulations demonstrate that, with either water exchange or inflow effects alone, the dependence on the physiologic and imaging parameters can be well characterized and therefore potentially offset. In the exchange only case, the parametric dependence of 3D simulations suggest that the best accuracy is achieved with high flip angles, short TR, and low blood contrast agent concentrations. However, for a 2D GRE sequence which is influenced by both water exchange and inflow, the simulations predict that the error trend as a function of the imaging and physiologic parameters is unpredictable and therefore difficult to compensate. With both 2D and 3D GRE the measured blood volume data in rat brain and tumor tissue demonstrate tissue-specific trends, which reflect differences in the considered physiologic parameters. The experimental data strongly support the computer simulations and also indicate that minimization of the physiological effects by proper selection of imaging parameters, contrast concentration, and volume calculation methods is crucial for accurate assessment of absolute blood volume fraction.

Animals↗

PubMed2001

Folding and stability of sweet protein single-chain monellin. An insight to protein engineering.

Engineered single-chain monellin (SCM) proteins were constructed by recombinant technology without disrupting the topology and sweet activity of native protein. Data from 8-anilinonaphthalene-1-sulfonic acid fluorescence, size-exclusion chromatography, and heteronuclear NMR strongly suggest the presence of a folding intermediate at 1.5 m GdnHCl for SCM protein. The structural feature of the folding intermediate from NMR data reveals that the secondary structures became mostly unstable, and protein experiences a dynamic equilibrium between native and unfolded state. All backbone amide protons exchange within 10 min, which imply that no stable hydrogen bonds exist in the secondary structural regions in the folding intermediate. From equilibrium unfolding and mutagenesis studies, the unfolding transition midpoints of mutant proteins gradually shifted toward lower denaturant concentration, indicating stability reductions of mutant proteins. Our results suggest that stability and folding pathways of SCM proteins could be regulated by a combined study of spectroscopy and mutagenesis, and these studies will provide useful information for understanding the folding kinetics of novel engineered proteins.

Amino Acid Sequence↗

PubMed2001

Mitochondrial NADH-cytochrome b(5) reductase plays a crucial role in the reduction of D-erythroascorbyl free radical in Saccharomyces cerevisiae.

The relevance of NADH-cytochrome b(5) reductase to the NADH-dependent reduction of D-erythroascorbyl free radical was investigated in Saccharomyces cerevisiae. MCR1, which is known to encode NADH-cytochrome b(5) reductase in S. cerevisiae, was disrupted by the insertion of URA3 gene into the gene of MCR1. In the mcr1 disruptant cells, the activity of NADH-D-erythroascorbyl free radical reductase almost disappeared and the intracellular level of D-erythroascorbic acid was about 11% of that of the congenic wild-type strain. In the transformant cells carrying MCR1 in multicopy plasmid, the intracellular level of D-erythroascorbic acid and the activity of NADH-D-erythroascorbyl free radical reductase increased up to 1.7-fold and 2.1-fold, respectively. Therefore, it indicated that the MCR1 product, mitochondrial NADH-cytochrome b(5) reductase, plays a key role in the NADH-dependent reduction of D-erythroascorbyl free radical in S. cerevisiae. On the other hand, the mcr1 disruptant cells were hypersensitive to hydrogen peroxide and menadione, and overexpression of MCR1 made the cells more resistant against oxidative stress. These results suggested that the mitochondrial NADH-cytochrome b(5) reductase functions as NADH-D-erythroascorbyl free radical reductase and plays an important role in the response to oxidative damage in S. cerevisiae.

Ascorbic Acid↗

PubMed2001

Enhancement of lysophosphatidic acid-induced ERK phosphorylation by phospholipase D1 via the formation of phosphatidic acid.

We made stable cell lines overexpressing PLD1 (GP-PLD1) from GP+envAm12 cell, a derivative of NIH 3T3 cell. PLD1 activity and extracellular signal-regulated kinase (ERK) phosphorylation were enhanced in GP-PLD1 cells by the treatment of lysophosphatidic acid (LPA). In contrast, these LPA-induced effects were attenuated with the pretreatment of pertussis toxin (PTX) or protein kinase C (PKC) inhibitor. Moreover, accumulation of phosphatidic acid (PA), a product of PLD action, potentiated the LPA-induced ERK activation in GP-PLD1 cells while blocking of PA production with the treatment of 1-butanol attenuated LPA-induced ERK phosphorylation. From these results, we suggest that LPA activate PLD1 through pertussis toxin-sensitive G protein and PKC-dependent pathways, then PA produced from PLD1 activation facilitate ERK phosphorylation.

3T3 Cells↗

PubMed2001

Effects of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) on the expression of inflammatory cytokines and apoptosis induction in rheumatoid synovial fibroblasts and monocytes.

This study was performed to investigate whether peroxisome proliterator-activated receptor-gamma (PPAR-gamma) exerted an anti-inflammatory effect on rheumatoid synovial cells and inhibited dysregulated proliferation. The expression of PPAR-gamma mRNA in cultured human synoviocytes and THP-1 cells was analysed by RT-PCR. PPAR-gamma was expressed in normal, osteoarthritis (OA), rheumatoid arthritis (RA) synovial cells as well as a human monocytic cell line, THP-1. In RA and OA synoviocytes, the induction of inflammatory cytokine mRNA expression such as TNF-alpha and IL-1beta was significantly inhibited by the natural PPAR-gamma agonist, 15 deoxy-Delta(12,14)prostaglandin J(2)(15d-PGJ(2)). The effect of PPAR-gamma on the nuclear factor (NF)-kappaB activity was tested by electrophoretic mobility shift assay (EMSA). Both troglitazone and 15d-PGJ(2)markedly inhibited TNF-alpha-induced NF-kappaB activation at 30 microM. However, PPAR-gamma agonist neither reduced proliferation nor induced apoptosis in RA synoviocytes when measured by XTT assay and fluorescence activated cell sorter (FACS) analysis. In contrast, it induced apoptosis in a dose-dependent manner in THP-1 cells and augmented TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis as well. In conclusion, these data demonstrate that PPAR-gamma is expressed in human synoviocytes and THP-1 cells, and the PPAR-gamma activation inhibits expression of inflammatory cytokines in RA synoviocytes. Furthermore, PPAR-gamma activation induces apoptosis by itself and augments TRAIL/Apo2L-induced apoptosis in THP-1 cells. These results suggest that PPAR-gamma agonists may provide a new therapeutic approach for RA.

Apoptosis↗

PubMed2001

Polymorphisms of the CTLA-4 exon 1 and promoter gene in systemic lupus erythematosus.

The objective of this study was to determine whether the polymorphisms of the CTLA-4 exon 1 (+49) and promoter (-318) are associated with susceptibility to systemic lupus erythematosus (SLE) and its clinical features. Polymerase chain reaction of genomic DNA-restriction fragment length polymorphism was used to determine genotypes of the CTLA-4 exon 1 (+49) and promoter (-318) in 80 SLE patients and 86 healthy control subjects. The genotype distribution of the CTLA-4 exon 1 (+49) differed between SLE patients and controls (chi2 = 6.74, 2 degrees of freedom (d.f.), P = 0.03). The CTLA-4 AG genotype occurred more frequently in patients with SLE (46.3% vs 33.7% controls). On the other hand, the CTLA-4 AA genotype as well as the CTLA-4 GG genotype was less frequent among SLE patients than among control subjects (1.3% vs 9.3% and 52.5% vs 57.0%, respectively). The genotype distribution of the CTLA-4 promoter (-318) differed between SLE patients and control subjects (CT, TT, CC; genotypes 27.5%, 0%, 72.5% vs 16.3%, 4.7%, 79.1% controls respectively, chi2 = 6.36, 2 d.f., P = 0.04). However, Fischer's exact or chi2 P-values for each genotypes of the CTLA-4 exon 1 (+49) and promoter (-318) between SLE and control group were > 0.05. Clinically, in the lupus patients there was no significant difference according to the CTLA-4 polymorphisms. In conclusion, no correlation was found between CTLA-4 exon 1 (+49) and promoter (-318) polymorphisms and SLE in our study.

Abatacept↗

PubMed2001

Genetic variations of cholesterol ester transfer protein gene in Koreans.

An absence of cholesterol ester transfer protein (CETP, protein; CETP, gene) results in an increase of the apolipoprotein AI levels and a decrease in the low density lipoprotein (LDL) levels. Thus, the CETP polymorphism is important in the assessment of risk of atherosclerosis. This study was conducted to elucidate the genotype distributions of the CETP polymorphism and association with plasma lipid levels in Koreans. The genotypes of the TaqI A and B polymorphic loci were associated with plasma triglyceride levels in the control and coronary artery disease (CAD) groups. There was linkage disequilibrium between TaqI A and B loci in the control group (chi2 = 5.58, p < 0.05). Association studies of the CETP polymorphism have been carried out mainly with Caucasian populations; however, the results have not been consistent among different populations. A possible explanation for this diversity among populations may be differences in genetic backgrounds, which may be more important than environmental factors. We discuss the reasons for the incompatibility of the CETP polymorphism among populations.

Alleles↗

PubMed2001

A case of BOOP developed during bucillamine treatment for rheumatoid.

We describe a patient with rheumatoid arthritis(RA) who developed bronchiolitis obliterans organizing pneumonia(BOOP) during the treatment of bucillamine. A 51 year-old man was admitted to the hospital for an abnormal shadow on his chest radiograph. He had been diagnosed as having RA 3 years previously and had been receiving 200 mg of bucillamine for 21 months. Two months prior to admission, he presented with a cough and his chest X-ray showed opacities in both lower lungs. He was treated with antibiotics for 2 months after the development of cough and lesions on the chest X-ray, but the symptoms and lung lesions became more aggravated. On admission, an HRCT revealed airspace consolidations in the subpleural space of both basal lungs and a CT-guided fine needle aspiration biopsy showed Masson's body filling air space, interstitial infiltration of acute and chronic inflammatory cells and type II cell hyperplasia, consistent with BOOP. Bucillamine was stopped and 50 mg of prednisolone was administered. His symptoms and infiltrations on the chest X-ray resolved. We suggest that bucillamine should be considered as a drug possibly associated with BOOP.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2001

Fas promoter -670 polymorphism is associated with development of anti-RNP antibodies in systemic lupus erythematosus.

OBJECTIVE: To evaluate whether the polymorphism of Fas promoter -670 is associated with susceptibility to systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) and their clinical features. METHODS: A polymerase chain reaction of a genomic DNA-restriction fragment length polymorphism was used to determine genotypes of the Fas promoter -670 in 87 patients with SLE, 87 with RA, and 87 healthy controls. A second cohort of SLE patients (n = 85) was included. Clinical manifestations were analyzed in each patient and correlated with the genotypes. RESULTS: The genotype distribution of the Fas promoter -670 did not differ between patients with SLE and control subjects (AA, GA, GG genotypes 31, 54, 15% vs 30, 55, 15% controls, respectively; chi-squared = 0.03, 2 df, p = 0.99) and between RA patients and controls (AA, GA, GG genotypes 38, 44, 18% vs 30, 55, 15% controls, respectively; chi-squared = 2.30, 2 df, p = 0.32). Regarding the clinical status of lupus patients according to Fas promoter -670 genotypes, there was no significant difference in age at onset, anti-dsDNA titer, C3, C4 level, renal involvement, number of American College of Rheumatology (ACR) criteria met, SLE Disease Activity Index, SLE International Collaborating Clinics/ACR Damage Index, or autoantibody profiles. However, the frequency of anti-RNP antibody was significantly different in the AA, GA, and GG groups (71, 25, 30%; chi-squared = 13.29, 2 df, p = 0.001). To confirm this finding, the Fas promoter -670 genotype was examined in a second cohort of SLE patients (n = 85). The result in the second cohort replicated the association shown in the first. In patients with RA, there was no significant difference in clinical and laboratory findings according to the Fas promoter -670 genotypes. CONCLUSION: Our data suggest that the Fas promoter -670 polymorphism is associated with development of anti-RNP antibodies in SLE.

Adolescent↗

PubMed2001

p53 codon 72 polymorphism and rheumatoid arthritis.

OBJECTIVE: To investigate whether the p53 codon 72 polymorphism is associated with susceptibility to rheumatoid arthritis (RA) and its clinical features. METHODS: A polymerase chain reaction of genomic DNA-restriction fragment length polymorphism was used to determine genotypes of the p53 codon 72 in 114 patients with RA and 114 healthy controls. Clinical/serological manifestations were analyzed in each patient and correlated with the genotypes. RESULTS: The genotype distribution of the p53 codon 72 did not differ between patients with RA and controls (Arg/Arg, Arg/Pro, Pro/Pro genotypes 38, 58, 18 vs 37, 60, 17 controls, respectively; chi-square = 0.08, 2 df, p = 0.96). No significant difference was found in allele frequencies between the groups. Clinically there was no significant difference in age at onset, functional class, physician's global assessment, ESR, CRP, RF titer, extraarticular and cervical spine involvement, frequencies of joint operation, and admission in RA patients according to the p53 codon 72 genotypes. However, the number of patients within each group was extremely small, for example only 5 patients with cervical spine involvement. No firm conclusions could safely be reached about clinical manifestations from this study. CONCLUSION: No association was found between the p53 codon 72 polymorphism and RA. Studies are needed to clarify the role of the p53 polymorphism in the pathogenesis of RA.

Adolescent↗

PubMed2000

Galactosylated chitosan-graft-dextran as hepatocyte-targeting DNA carrier.

Lactobionic acid bearing galactose group was coupled with chitosan for liver specificity, and dextran was grafted to galactosylated chitosan (GC) for stability in water. Compared to the GC/DNA complex, the stability of the galactosylated chitosan-graft-dextran (GCD)/DNA complex could be enhanced. The particle size of the GCD/DNA complexes decreased as the charge ratio of GCD to DNA increased. Conformational change of DNA did not occur after complex formation with GCD compared with the conformation of DNA itself. The GCD/DNA complexes were only transfected into Chang liver cells and that of Hep G2 having asialoglycoprotein receptors (ASGR), indicative of specific interaction of ASGRs on cells and galactose ligands on chitosan.

Asialoglycoprotein Receptor↗

PubMed2000

Contrast agent-enhanced magnetic resonance imaging of skeletal muscle damage in animal models of muscular dystrophy.

Membrane lesions play an early role in the pathogenesis of muscular dystrophy. Using a new albumin-targeted contrast agent (MS-325), sarcolemmal integrity of two animal models for muscular dystrophy was studied by MRI. Intravenously injected MS-325 does not enter skeletal muscle of normal mice. However, mdx and Sgca-null mutant mice, animal models for Duchenne and sarcoglycan-deficient limb-girdle muscular dystrophy, respectively, showed significant accumulation of MS-325 in skeletal muscle. The results suggest that contrast agent-enhanced MRI could serve as a common, noninvasive imaging procedure for evaluating the localization, extent, and mechanisms of skeletal muscle damage in muscular dystrophy. Furthermore, this method is expected to facilitate assessment of therapeutic approaches in these diseases.

Animals↗

PubMed2000

Regulation of phospholipase D2 by H(2)O(2) in PC12 cells.

Phospholipase D2 (PLD2) is expressed in brain and inhibited by synuclein, which is involved in Parkinson's and Alzheimer's diseases. However, the activation mechanism of PLD2 in neuronal cells has not been defined clearly. Hydrogen peroxide (H(2)O(2)) plays roles in the neurodegenerative diseases and also acts as a second messenger of various molecules such as nerve growth factor. To study regulation mechanisms of PLD2 by H(2)O(2) in neuronal cells, we have made stable PC12 cell lines expressing PLD2 (PLD2-PC12 cells). H(2)O(2) treatment stimulated PLD activity in PLD2-PC12 cells in a dose- and time-dependent manner. This activation was inhibited by the treatment with protein kinase C (PKC) inhibitors or by depletion of PKCalpha, -delta, and -epsilon. Phorbol ester markedly activated PLD2. Co-treatment with phorbol ester and H(2)O(2) did not show an additive effect. Chelation of extracellular calcium substantially blocked the H(2)O(2)-induced activation of PLD2. A calcium ionophore induced PLD2 activation in a PKC-dependent manner. Protein-tyrosine kinase inhibitors inhibited H(2)O(2)-induced PLD activation slightly. These data indicate that H(2)O(2) can activate PLD2 in PC12 cells and that this activation is largely dependent on PKC and Ca(2+) ions and minimally dependent on tyrosine phosphorylation.

Animals↗

PubMed2000

Development of a fluorogenic probe-based PCR assay for detection of Bacillus cereus in nonfat dry milk.

A fluorogenic probe-based PCR assay was developed and evaluated for its utility in detecting Bacillus cereus in nonfat dry milk. Regions of the hemolysin and cereolysin AB genes from an initial group of two B. cereus isolates and two Bacillus thuringiensis isolates were cloned and sequenced. Three single-base differences in two B. cereus strains were identified in the cereolysin AB gene at nucleotides 866, 875, and 1287, while there were no species-consistent differences found in the hemolysin gene. A fluorogenic probe-based PCR assay was developed which utilizes the 5'-to-3' exonuclease of Taq polymerase, and two fluorogenic probes were evaluated. One fluorogenic probe (cerTAQ-1) was designed to be specific for the nucleotide differences at bases 866 and 875 found in B. cereus. A total of 51 out of 72 B. cereus strains tested positive with the cerTAQ-1 probe, while only 1 out of 5 B. thuringiensis strains tested positive. Sequence analysis of the negative B. cereus strains revealed additional polymorphism found in the cereolysin probe target. A second probe (cerTAQ-2) was designed to account for additional polymorphic sequences found in the cerTAQ-1-negative B. cereus strains. A total of 35 out of 39 B. cereus strains tested positive (including 10 of 14 previously negative strains) with cerTAQ-2, although the assay readout was uniformly lower with this probe than with cerTAQ-1. A PCR assay using cerTAQ-1 was able to detect approximately 58 B. cereus CFU in 1 g of artificially contaminated nonfat dry milk. Forty-three nonfat dry milk samples were tested for the presence of B. cereus with the most-probable-number technique and the fluorogenic PCR assay. Twelve of the 43 samples were contaminated with B. cereus at levels greater than or equal to 43 CFU/g, and all 12 of these samples tested positive with the fluorogenic PCR assay. Of the remaining 31 samples, 12 were B. cereus negative and 19 were contaminated with B. cereus at levels ranging from 3 to 9 CFU/g. All 31 of these samples were negative in the fluorogenic PCR assay. Although not totally inclusive, the PCR-based assay with cerTAQ-1 is able to specifically detect B. cereus in nonfat dry milk.

Animals↗