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Biomedical subjects

W B Kim

Publications and source records attributed to W B Kim.

At least 37 records · Page 2Linked to original sources

Apicidin, an inhibitor of histone deacetylase, prevents H-ras-induced invasive phenotype.

Cancer metastasis represents the most important cause of cancer death and agents that may inhibit tumor cell invasion have been extensively pursued. In the present study, we have examined the anti-invasive effect of apicidin [cyclo(N-O-methyl-L-tryptophanyl-L-isoleucinyl-D-pipecolinyl -L-2-amin o-8-oxodecanoyl)], a fungal metabolite that was identified as an antiprotozoal agent known to inhibit parasite histone deacetylase (HDAC). We show that apicidin significantly inhibits H-ras-induced invasive phenotype of MCF10A human breast epithelial cells in parallel with a specific downregulation of matrix metalloproteinase (MMP)-2, but not MMP-9. We also show that apicidin induces a morphological reversal and growth inhibition of H-ras MCF10A cells similar to that induced by other HDAC inhibitors. Taken in conjunction with the fact that uncontrolled ras activation is probably the most common genetic defect in human cancer cells, our data showing the anti-invasive and detransforming activities of apicidin in H-ras-transformed MCF10A cells may suggest a potential use of HDAC inhibitors for treatment of cancer.

Breast↗

Role of glucose utilization in the restoration of hypophysectomy-induced hepatic cytochrome P450 2E1 by growth hormone in rats.

Growth hormone and insulin are the primary determinants for cytochrome P450 2E1 (CYP2E1) expression. The role of glucose on the induction of CYP2E1 by hypophysectomy and on the restorative effect by growth hormone was investigated in the rat liver. Western and Northern blot analyses revealed that hypophysectomy induced CYP2E1 by 5-fold at 1-4 weeks, relative to control, with a concomitant increase in CYP2E1 mRNA. Hypophysectomized rats (HXR) showed a 20% reduction in the plasma glucose level. Hypophysectomy-induced increase in the CYP2E1 mRNA was completely abolished by glucose feeding in drinking water (10%) for 7 days. Treatment of HXR with hGH (2 I.U./kg, twice a day, for 7 days) inhibited the increases in CYP2E1 protein and mRNA levels with restoration of the plasma glucose level. In contrast to the effect of human growth hormone (hGH) on CYP2E1 in HXR with free access to foods, CYP2E1 expression failed to be restored by hGH in starving HXR. However, glucose feeding of starving HXR abolished the induction of CYP2E1. Effects of hypophysectomy and hGH treatment were studied in streptozotocin-induced diabetic rats. Insulin, but not hGH, prevented an increase in CYP2E1 mRNA in diabetic rats. The hepatic CYP2E1 induction in hypophysectomized diabetic rats was inhibited by hGH treatment, indicating that the hGH effect on CYP2E1 expression did not involve insulin production. These results provide evidence that the induction of hepatic CYP2E1 by hypophysectomy may result from reduced glucose utilization, and that the effect of hGH on CYP2E1 expression may be mediated with enhanced glucose utilization, but not with insulin production.

Animals↗

Factors influencing the protein binding of a new phosphodiesterase V inhibitor, DA-8159, using an equilibrium dialysis technique.

Various factors influencing the protein binding of DA-8159 to 4% human serum albumin (HSA) were evaluated using an equilibrium dialysis technique at an initial DA-8159 concentration of 5 microg/mL. It took approximately 8 h incubation to reach an equilibrium between 4% HSA and an isotonic phosphate buffer of pH 7.4 containing 3% of dextran ('the buffer') using a Spectra/Por 2 membrane (mol. wt. cut-off: 12,000--14,000) in a water bath shaker kept at 37 degrees C and at a rate of 50 oscillations per min. The extent of binding was dependent on DA-8159 concentrations, HSA concentrations, incubation temperature, buffer pH, and alpha-1-acid glycoprotein (AAG) concentrations. The binding of DA-8159 in heparinized human plasma (93.9%) was significantly higher than in rats (81.4%), rabbits (80.4%), and dogs (82.2%), and this could be due to differences in AAG concentrations in plasma.

Animals↗

Ionomycin restores taurine transporter activity in cyclosporin-A treated macrophages.

Taurine is accumulated at high concentrations in various tissues. The taurine transporter (TAUT) is responsible for the transportation of taurine in the cell. The transporter is affected by various stimuli to maintain cell volume. Macrophage cell volume varies in its activated states. In our experiment, it was found that the murine macrophage cell line, RAW264.7, expressed TAUT protein in its membrane. Its transporting activities could be blocked by beta-amino acid such as beta-alanine, but not by alpha-amino acids in this cell line, when assessed in RAW264.7 cells under the influence of immunosuppressive reagents, the activity of the TAUT was decreased by treatment with rapamycin (RM) or cyclosporin A (CSA). However, when ionomycin (IM) was added to this system, TAUT activity was recovered only in CSA-treated cells, in a concentration-dependent manner, in order to inhibit voltage gated Ca2+ channels, calmidazolium was added to the RAW264.7 cell line. Treatment of the cells with calmidazolium completely blocked TAUT. Furthermore, addition of IM to this system resulted in recovery the activity of TAUT again. When we added phorbol myristyl acetate (PMA) to the cell line, secretion of nitric oxide (NO) was increased 4-fold and the TAUT activity was decreased 5-fold. However, the addition of N-nitro L-arginine methyl ester (L-NAME), an inducible NO synthase (iNOS) inhibitor, to the PMA-treated cells induced recovery of TAUT activity. These results showed that the activity of TAUT was sensitive to both the intracellular concentrations of Ca2+ and NO.

Animals↗

Erectogenic effect of the selective phosphodiesterase type 5 inhibitor, DA-8159.

DA-8159, a new phosphodiesterase 5 inhibitor, was assessed for its erectogenic potential by a penile erection test in rats, the relaxation of isolated rabbit corpus cavernosum (CC), and estimation of the intracavernous pressure (ICP) in the anesthetized dog. Oral administration of DA-8159 (0.3 to 1 mg/kg) increased the number of erections in rats with increasing dosage, with the highest penile erection index at 10 mg/kg. DA-8159 induced the relaxation of phenylephrine (PHE)-induced contractions in the rabbit CC and decreased the IC50 of the nitric oxide donor sodium nitroprusside (SNP) in a dose-dependent fashion. In pentobarbital-anesthetized dogs, the intravenous administration of DA-8159 (1 approximately 300 g/kg) potentiated the increase in ICP induced by the intracavernosal SNP in a dose-related manner. These findings suggest that DA-8159 has significant therapeutic potential in the treatment of erectile dysfunction.

Animals↗

Efficiency of promoter and cell line in high-level expression of erythropoietin.

Efficiency of viral promoters and various cell lines in directing high-level expression of human erythropoietin (Epo) was investigated. To investigate the effects of various viral promoters and cell lines on the Epo expression level, genomic Epo with the 5' and 3' untranslated regions (UTRs) deleted was cloned next to the simian virus 40 early promoter, cytomegalovirus early promoter or SRalpha promoter. These expression vectors were transfected into COS-7, BHK-21 and Chinese hamster ovary (CHO)/dhfr(-) cells, respectively. The COS-7 cells transfected with the vector containing the SRalpha promoter showed the highest expression level ( approximately 103 IU/ml) at 72 h post-transfection. For the development of Epo-producing stable cell lines, BHK-21 and CHO/dhfr(-) cells transfected with the 5',3'-UTR-deleted genomic Epo under the control of the SRalpha promoter were cultured with media containing zeocin. Several clones of zeocin-resistant BHK-21 and CHO/dhfr(-) cells were cultured in the presence of methotrexate (MTX). A BHK-21 clone selected in the presence of 500 nM MTX expressed and secreted approximately 490 IU/ml Epo into the medium. A CHO/dhfr(-) clone selected in the presence of 20 nM MTX expressed and secreted approximately 45 IU/ml Epo into the medium. Southern-blot analysis indicated that enhancement of Epo expression in the MTX-resistant stable cells might be related to the amplification of gene copy number.

Animals↗

Polymorphism in the promoter and exon 1 of the cytotoxic T lymphocyte antigen-4 gene associated with autoimmune thyroid disease in Koreans.

The objective of this study was to examine the polymorphism in the cytotoxic T lymphocyte antigen-4 (CTLA-4) gene and its relationship with autoimmune thyroid disease in Koreans. Polymorphism in the promoter and exon 1 of CTLA-4, clinical symptoms of disease and thyrotropin receptor antibody (TSHRAb) characteristics were analyzed. Polymorphism was detected using restriction fragment length polymorphism and polymerase chain reaction amplification of genomic DNA. All subjects were Korean (97 Graves' disease, 110 Hashimoto's thyroiditis, and 199 normal controls). Graves' patients had significantly more G allele in exon 1 and C allele in the promoter than controls. When the exon 1 genotype was GG, the frequency of CC genotype in the promoter was higher. Allele frequencies in CTLA-4 did not differ from controls in patients with Hashimoto's thyroiditis. In Graves' patients, there were significant differences between genotypic groups in serum triiodothyronine (T3) levels and the presence of ophthalmopathy. However, TSHRAbs and other clinical characteristics were not significantly different. In conclusion, the CTLA-4 G allele in exon 1 and C allele in the promoter may confer genetic susceptibility to Graves' disease in Koreans. These two polymorphisms are additional and dependent genetic risk markers that help to characterize risk alleles within CTLA-4 gene.

Abatacept↗

The prevalence and clinical significance of blocking thyrotropin receptor antibodies in untreated hyperthyroid Graves' disease.

The goal of this study was to evaluate the clinical significance of the blocking thyrotropin receptor antibodies (TSHRAb) in Graves' disease. The amount of blocking and stimulating TSHRAb were measured in 200 patients with untreated hyperthyroid Graves' disease using several cell lines carrying different TSHR chimera. Stimulating TSHRAb were measured in Chinese hamster ovary (CHO) cells with wild-type human TSHR (CHO-hTSHR) or a TSHR chimera with residues 90-165 (Mc2) or 8-165 (Mc1+2) substituted by equivalent residues of rat luteinizing hormone/chorionic gonadotrophin (LH/CG) receptor or in FRTL-5 cells. Blocking TSHRAb were measured in Mc2 cells. The activities of different TSHRAb were assessed and clinical features were compared to patients who were positive or negative for blocking TSHRAb antibodies. Blocking TSHRAbs were detected in 18.5% of patients (37/200) with hyperthyroid Graves' disease. Patients with blocking antibodies had significantly lower mean stimulating TSHRAb activities than those without blocking antibodies in wild-type CHO-hTSHR cells (301 +/- 179 vs. 446% +/- 537%, p = 0.005). Mean stimulating TSHRAb activities measured by FRTL-5, Mc1+2, or Mc2 cells and mean thyrotropin receptor inhibitor immunoglobulin (TBII) activities were not different between the two groups. The patients with blocking antibodies were not different from those without blocking antibodies in age, gender ratio, initial serum free thyroxine (T4) levels, or goiter size. However, the prevalence of exophthalmos was higher (35.1% vs. 17.5%, p = 0.024) in the patients with blocking antibodies than those without. In summary, the presence of blocking TSHRAb is not rare in patients with hyperthyroid Graves' disease when measured with chimeric receptor expressing cells. Blocking TSHRAb in Graves' sera do not strongly antagonize the action of stimulating TSHRAb in vivo, but could be a major factor responsible for underestimation of stimulating TSHRAb activities measured by CHO-hTSHR. The association of blocking TSHRAb with ophthalmopathy suggests that the TSHRAb repertoire of Graves' patients is different in those who do and who do not have ophthalmopathy.

Adult↗

Identification of a calmodulin-regulated soybean Ca(2+)-ATPase (SCA1) that is located in the plasma membrane.

Ca(2)+-ATPases are key regulators of Ca(2+) ion efflux in all eukaryotes. Animal cells have two distinct families of Ca(2+) pumps, with calmodulin-stimulated pumps (type IIB pumps) found exclusively at the plasma membrane. In plants, no equivalent type IIB pump located at the plasma membrane has been identified at the molecular level, although related isoforms have been identified in non-plasma membrane locations. Here, we identify a plant cDNA, designated SCA1 (for soybean Ca(2+)-ATPase 1), that encodes Ca(2+)-ATPase and is located at the plasma membrane. The plasma membrane localization was determined by sucrose gradient and aqueous two-phase membrane fractionations and was confirmed by the localization of SCA1p tagged with a green fluorescent protein. The Ca(2+)-ATPase activity of the SCA1p was increased approximately sixfold by calmodulin (K(1/2) approximately 10 nM). Two calmodulin binding sequences were identified in the N-terminal domain. An N-terminal truncation mutant that deletes sequence through the two calmodulin binding sites was able to complement a yeast mutant (K616) that was deficient in two endogenous Ca(2+) pumps. Our results indicate that SCA1p is structurally distinct from the plasma membrane-localized Ca(2+) pump in animal cells, belonging instead to a novel family of plant type IIB pumps found in multiple subcellular locations. In plant cells from soybean, expression of this plasma membrane pump was highly and rapidly induced by salt (NaCl) stress and a fungal elicitor but not by osmotic stress.

Amino Acid Motifs↗

Isolation of a potent anti-MRSA sesquiterpenoid quinone from Ulmus davidiana var. japonica.

A highly potent anti-MRSA sesquiterpenoid has been isolated from Ulmus davidiana var. japonica, which has been traditionally used to treat infectious diseases in Korea. This naturally occurring antibiotic was identified as mansonone F (1). This compound has been found to be highly active specifically against MRSA and showed an MIC range of 0.39-3.13 microg/ml which is comparable to that of vancomycin.

Anti-Bacterial Agents↗

Increased prevalence of autoimmune thyroid disease in patients with type 1 diabetes.

BACKGROUND: Type 1 diabetes mellitus is frequently associated with other autoimmune diseases. The occurrence of common features of autoimmune diseases and the coassociation of multiple autoimmune diseases in the same individual or family supports the notion that there may be common genetic factors. METHODS: To investigate potential clustering of autoimmune thyroid disease (ATD) among type 1 diabetes patients and the contribution of common susceptibility genes to this, HLA DR/DQ alleles as well as antithyroid autoantibodies were measured in 115 Korean patients with type 1 diabetes and their 96 first-degree family members. RESULTS: Twenty-five percent of the patients had ATD, whereas 3 of 36 (8%) age-matched normal controls had ATD (RR = 3.7, p < 0.05). Twenty-six of ninty-six (27%) type 1 diabetes family members had ATD. No differences in the distribution of HLA alleles/haplotypes and genotypes between the patients with and without ATD were found. CONCLUSION: From this finding, we could assess that individuals with type 1 diabetes and their relatives frequently develop ATD, perhaps due to common susceptibility genes that are shared among first degree relatives.

Adult↗

Bioequivalence assessment of closerin capsule to dura seromycin capsule of cycloserine after a single oral dose administration to healthy male volunteers.

AIM: A bioequivalence study of the closerin capsules to the dura seromycin capsules was conducted. PATIENTS AND METHODS: Twenty-four healthy male Korean volunteers received each medicine at the cycloserine dose of 250 mg in a 2 x 2 crossover study. There was a one-week washout period between the doses. Plasma concentrations of cycloserine were monitored by a high-performance liquid chromatography for over a period of 72 hours after the administration. AUCinf (the area under the plasma concentration-time curve from time zero to time infinity) was calculated by the linear-log trapezoidal method. Cmax (maximum plasma drug concentration) and Tmax (time to reach Cmax) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUCinf and Cmax, and untransformed Tmax. RESULTS: There were no significant differences between the medications in AUCinf and Cmax. The point estimates and 90% confidence intervals for AUCinf (parametric) and Cmax (parametric) were, in point estimate (90% confidence interval), 0.992 (0.950 approximately 1.037) and 1.051 (0.965 approximatly 1.144), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration Guidelines. The corresponding value of Tmax was 0.000 (-0.250 approximatly 0.125). Moreover, the modified Pitman-Morgan's adjusted F test and equal variance test (one-sided) indicated that the 2 medications were comparable in intra- and inter-individual variability in cycloserine bioavailability. CONCLUSION: Therefore, these results indicate that the 2 medications of cycloserine are bioequivalent and, thus, may be prescribed interchangeably.

Administration, Oral↗

One-month parenteral toxicity study of recombinant human basic fibroblast growth factor in dogs.

A 1-mo toxicity study followed by a 1-mo recovery period of recombinant human basic fibroblast growth factor (bFGF) was performed using Beagle dogs at doses of 30, 120 or 480 mg/kg/d to estimate the no observed adverse effect level (NOAEL). Subcutaneous thickening was seen and its incidence, as well as that of stiffness of the injection sites, increased with dose. There were neither dead animals nor significant changes of body weight during the experimental period. In addition, no significant bFGF-related changes were found in ophthalmologic and histopathological examination, urinalysis and hematological, biochemical and organ weight parameters. At necropsy, red-brownish spots and/or nodule formations were recognized in a dose-dependent manner. Splenomegaly was noted in the 480 mg/kg group, but these findings had a low incidence in all dose groups. The findings in the dosing period disappeared or were ameliorated during the recovery period. The above data suggests the NOAEL of bFGF in Beagle dogs is >480 mg/kg/d.

Animals↗

Pharmacokinetics, stability, and blood partition of DA-8159, a new phosphodiesterase V inhibitor.

The pharmacokinetics of DA-8159, a new phosphodiesterase V inhibitor, after 1 min intravenous, 30 mg/kg, and oral, 30 mg/kg, administration of the drug to rats, the stability of DA-8159 in various pH solutions ranging from 1 to 13, and human and rat plasma and urine, and the blood partition of DA-8159 between plasma and blood cells of rabbit were evaluated. After intravenous administration, DA-8159 was eliminated fast with the mean total body clearance of 126 ml/min/kg, and was almost completely metabolized in rats; 5.98% of intravenous dose of DA-8159 were excreted unchanged in 24-hr urine. The extent of absolute oral bioavailibility of DA-8159 was approximately 25%. The apparent volume of distribution at steady state was considerably large, 15048 ml/kg, suggesting that DA-8159 has a good affinity to rat tissues. DA-8159 was relatively stable in various pH solutions, and human and rat plasma and urine for up to 48 h incubation in a water-bath shaker kept at 37 degrees C and at a rate of 50 oscillations per min. DA-8159 reached equilibrium fast (within 30 sec mixing manually) between plasma and blood cells of rabbit blood and the plasma-to-blood cell concentration ratios were independent of initial blood concentrations of DA-8159, 1, 5, and 10 microg/ml, when the rabbit whole blood was incubated for up to 120 min; the ratios were in the range of 0.662-0.812. There was no in vitro 'blood storage effect' in the plasma concentration of DA-8159.

3',5'-Cyclic-GMP Phosphodiesterases↗

Capsaicin binds to the intracellular domain of the capsaicin-activated ion channel.

Capsaicin (CAP) excites small sensory neurons, causing pain, neurogenic inflammation, and other visceral reflexes. These effects have been proposed to be the result of CAP activation of a nonselective cation current. It is generally assumed that CAP binds to an extracellular domain of the membrane receptor. However, the exact binding site is not known because of the lipophilic nature of CAP. To determine whether the binding domain is extracellular or intracellular, we tested the effect of a synthetic water-soluble CAP analog, DA-5018.HCl, on current activation. CAP activated the 45 pS (at -60 mV) nonselective cation channel from either side of the membrane. However, DA-5018.HCl, which had a greater potency and efficacy than CAP, activated the channels only from the cytosolic side of the patch membrane in a capsazepine, a CAP receptor antagonist, reversible manner. When applied extracellularly, DA-5018. HCl did not, but CAP did, activate whole-cell currents in sensory neurons, as well as in oocytes expressing vanilloid receptor 1, a recently cloned CAP receptor. Hydrogen ions, reported as a possible endogenous activator of cation current, failed to elicit any current when acidic medium (pH 5.0-6.0) was applied intracellularly, indicating that H+ does not mediate the CAP effect. These results indicate that CAP and its analog bind to the cytosolic domain of the CAP receptor and suggest that an endogenous CAP-like substance other than H+ may be present in the cell.

Animals↗

Nephroprotective effect of betamipron on a new carbapenem, DA-1131, in rabbits.

The nephroprotective effect of betamipron (200 mg/kg) was evaluated after intravenous administration of a high dose of DA-1131 (200 mg/kg) to rabbits. Extensive tubular necrosis was observed without betamipron but the necrosis was not observed with betamipron at 8 h after intravenous administration of DA-1131 based on kidney microscopy. By treatment with betamipron, the amounts and tissue to plasma (T/P) ratios of DA-1131 in renal cortex and whole kidney decreased significantly (65-91% decrease) at both 30 min and 2 h after intravenous administration of the drug to rabbits. This indicated that the accumulation of DA-1131 in rabbit renal cortex and whole kidney was inhibited by betamipron. This resulted in significantly greater percentages of intravenous DA-1131 excreted in urine as unchanged drug, 60.9 versus 40.1%, and significantly faster renal clearance (Cl(r)) of DA-1131 (6.10 versus 3.22 mL/min/kg) by treatment with betamipron. By treatment with betamipron, the amounts and T/P ratios of DA-1131 in renal cortex and whole kidney decreased significantly from 30 min and the renal function remained intact at 8 h after intravenous administration of DA-1131. The above data suggested that the nephroprotective effect of betamipron was fast and persisted for a long period of time in rabbits.

Alanine↗

Antipruritic effect of DA-5018, a capsaicin derivative, in mice.

The antipruritic effect of DA-5018, a capsaicin derivative, was examined in mice. Male ICR mice were topically pretreated with Zostrix-HP (0.075% capsaicin cream), 0.1%, 0.3% DA-5018 cream or cream base (control) twice daily for 4 days. One hour after the last application, itch was induced either by compound 48/80 (50 microg, s.c.) or leukotriene B4 (0.03 nmol, i.d.) injection into the rostral back of the animals, and the number of scratches made by the animals at the injection site was counted for 60 min post-injection. DA-5018 cream (both 0.1 and 0.3%) significantly inhibited compound 48/80-induced scratching when compared with the cream base control (p<0.01), while Zostrix-HP showed minimal inhibition of the scratching behavior. In leukotriene B4-induced itch model, Zostrix-HP and 0.3% DA-5018 cream significantly inhibited the scratching during the first 10-min period (p<0.01). The results suggest that DA-5018 cream can be used as an antipruritic agent and warrant clinical evaluation.

Administration, Topical↗

Effect of DA-6034, a derivative of flavonoid, on experimental animal models of inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a multifactorial disorder with unknown etiology and pathogenesis. DA-6034, 7-carboxymethyloxy-3', 4', 5-trimethoxy flavone, is a synthetic flavonoid known to possess anti-inflammatory activity. This study was performed to evaluate the oral therapeutic effect of DA-6034 in three experimental animal models of IBD: two chemical-induced IBD models of rats and the human leukocyte antigen (HLA)-B27 transgenic rat model known to develop spontaneous colitis without the use of exogenous agents. Acute chemical colitis was induced by intracolonic instillation of 1.2 ml of 4% acetic acid solution. Prednisolone (1 mg/kg), sulfasalazine (100 mg/kg) and DA-6034 (0.3 to approximately 3 mg/kg) were orally administered twice daily for 6 days in these rats. In addition, chronic chemical colitis was induced by intracolonic administration of trinitrobenzene sulfonic acid (TNBS) 30 mg in 50% ethanol and agents were orally administered for 6 or 20 days. In chemical-induced IBD models, all of these agents reduced the severity of colitis and specially, DA-6034 (3 mg/kg) showed more potent effect than other drugs in macroscopic lesion score. In HLA-B27 transgenic rats, DA-6034 (3 mg/kg) and prednisolone (0.5 mg/kg) were treated orally twice daily for 6 weeks. The HLA-B27 transgenic rats showed only mild colitis, compared with the chemical-induced colitis models. DA-6034 ameliorated the loose stool and decreased microscopic damage, which is the important indicator of this model. In conclusion, oral therapy of DA-6034 attenuated the macroscopic and histologic damages of the colon in all three experimental models of IBD, which suggest that DA-6034 could be a promising drug in the treatment of IBD.

Acetic Acid↗