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Biomedical subjects

Y H Kim

Publications and source records attributed to Y H Kim.

At least 19 recordsLinked to original sources
PubMed2003

Construction of a deep coverage BAC library from Capsicum annuum, 'CM334'.

A bacterial artificial chromosome (BAC) library consisting of 235,000 clones with an average insert size of 130 kb was constructed from Capsicum annuum, 'CM334'. Based on a pepper haploid genome size of 2,702 Mbp/C, the BAC library is estimated to contain approximately 12 genome equivalents and represents at least 99% of the pepper genome. Screening of the library with mitochondrial DNA probes (coxII, coxIII, atp6 and atp9) and chloroplast DNA probes (atpB, rbcL) indicated that contamination with cytoplasmic DNA was less than 0.5%. To estimate the possibility of isolating a specific clone, the library was screened with single or low-copy gene-specific probes and RFLP probes. Screening of high density BAC filters with RFLP markers linked to L (TMV resistance), y (fruit color), C2 (fruit color) and C (pungency) loci under high stringency conditions revealed that at least three positive BAC clones were found per each probe. This fact indicates that the library is highly reliable and represents a resource for map-based cloning, physical mapping, and characterization of upstream and downstream regulations of the chili pepper genes.

Capsicum↗
PubMed2003

Optimum electrode configuration for detection of arm movement using bio-impedance.

A four-channel impedance measurement system, including a two-channel goniometer, to analyse human arm movement, was constructed. Impedances and joint angles were simultaneously measured for wrist and elbow movements. As the impedance changes resulting from wrist and elbow movements depended heavily on electrode placement, the optimum electrode configurations for those movements were determined by searching for high correlation coefficients, large impedance changes and minimum interferences in ten subjects (age: 29 +/- 6 years). The optimum electrode configurations showed very strong relationships between the wrist joint angle and forearm impedance (correlation coefficient= 0.95 +/- 0.04) and between the elbow joint angle and upper arm impedance (correlation coefficient= -0.97 +/- 0.03). Although the measured impedance changes of the wrist (1.1 +/-1.5 ohms) and elbow (-5.0 +/-2.9 ohms) varied between individuals, the reproducibilities of wrist and elbow impedance changes of five subjects were 5.8 +/- 1.8% and 4.6 +/- 1.4% for the optimum electrode pairs, respectively. It is proposed that this optimum electrode configuration would be useful for future studies involving the accurate measurement of arm movements by the impedance method.

Arm↗
PubMed2003

Cytotoxicity of yellow sand in lung epithelial cells.

The present study was carried out to observe the cytotoxicity of yellow sand in comparison with silica and titanium dioxide in a rat alveolar type II cell line (RLE-6TN). Yellow sand (China Loess) was obtained from the loess layer in the Gunsu Province of China. The mean particle diameter of yellow sand was about 0.003 +/- 0.001 mm. Major elements of yellow sand were Si(27.7 +/- 0.6%), Al(6.01 +/- 0.17%), and Ca(5.83 +/- 0.23%) in that order. Silica and yellow sand significantly decreased cell viability and increased [Ca2+]i. All three particles increased the generation of H2O2. TiO2 did not change Fenton activity, while silica induced a slight increase of Fenton activity. In contrast, yellow sand induced a significant increase of Fenton activity. Silica, yellow sand and TiO2 induced significant nitrite formations in RLE-6TN cells. Silica showed the highest increase in nitrite formation, while yellow sand induced the least formation of nitrite. Silica and yellow sand increased the release of TNF-a. Based on these results, we suggest that yellow sand can induce cytotoxicity in RLE-6TN cells and reactive oxygen species, Fenton activity and reactive nitrogen species might be involved in this toxicity.

Aluminum↗
PubMed2003

Synthesis of Si, Mg substituted hydroxyapatites and their sintering behaviors.

Si, Mg-substituted hydroxyapatites, alone and co-substituted, have been prepared to obtain biomaterials having an improved biocompatibility. From FT-IR, XRD and ICP analyses, it was confirmed that single phases of hydroxyapatite substituted by Si alone or co-substituted by Si, Mg. The XRD data indicated the absence of extra phases related to silicon and magnesium oxide or other calcium phosphate species. Si-substituted hydroxyapatite of up to 2 wt% for Si and Si, Mg co-substituted hydroxyapatite of 1 wt% for the each ion keep their original structures intact for the sintering temperatures of up to 1200 degrees C. However, it is observed that ion substitutions by an amount higher than the above ratios for each hydroxyapatite lead to destabilization of original structures of the hydroxyapatite and to the production of tricalcium phosphate and calcium phosphate silicate phases when the samples were sintered at 1100 degrees C or higher.

Biocompatible Materials↗
PubMed2003

Relation between insulin resistance and hematological parameters in elderly Koreans-Southwest Seoul (SWS) Study.

In this study, we investigated the relation between insulin resistance and hematological parameters in elderly Koreans. This study included 1314 non-diabetic subjects over the age of 60, selected from a cross-sectional study, which was conducted in 1999 in Seoul, Korea. We measured fasting and post-load 2 h plasma glucose, insulin levels, lipid profiles, anthropometric measures, and hematological parameters. The degree of insulin resistance was assessed using the homeostasis model assessment (HOMA). We found a correlation between insulin resistance and hemoglobin concentrations in non-smoking men (r=0.20, P=0.0186). In non-smoking women, insulin resistance correlated with hemoglobin (r=0.10, P=0.0017) and with white blood cell (WBC) count (r=0.15, P=0.001). Hemoglobin concentrations and WBC counts were also associated with other components of the insulin resistance syndrome such as body mass index, blood pressure, lipid profiles and fasting plasma insulin levels (surrogate for insulin resistance). Furthermore, the group in the upper quartile for insulin resistance showed higher hemoglobin concentrations and WBC counts than the lower quartile, independent of smoking status and serum iron concentrations. Using HOMA-IR as a dependent variable in a multiple regression analysis, age, body mass index (BMI), waist-to-hip ratio (WHR), systolic blood pressure, HDL cholesterol, triglyceride, WBC count, hemoglobin, hematocrit and serum TIBC were significant. Our results provide support for a relation between insulin resistance/hyperinsulinemia and hematological parameters such as hemoglobin concentrations and WBC counts in elderly Koreans. This suggests that increased erythropoiesis and subclinical inflammation could be part of the metabolic syndrome in elderly Koreans.

Aged↗
PubMed2003

Characterization of B cell membrane receptors of polysaccharide isolated from the root of Acanthopanax koreanum.

We investigated the immunomodulatory activity of polysaccharide isolated from the root of Acanthopanax koreanum (AK) at the cellular level. AK directly increased B cell proliferation and antibody production, but did not affect the expression of IL-2, IFN-gamma or IL-4 by T cells, or T cell proliferation in vitro. Since AK cannot penetrate cells due to its large molecular mass, B cell activation may be caused by the surface binding of AK to B cell-specific receptors. The role of TLR4 as an AK receptor was shown by the fact that AK activity in B cells from C3H/HeJ mice, which are known to have a defective Toll-like receptor (TLR)-4, was found to be reduced compared with that in control cells from C3H/HeN mice. AK activity was also reduced by antibodies blocking TLR2, TLR4, CD19 or CD79b, but not by an antibody blocking CD38, which suggests AK receptor profiling in B cells. Two main differences between AK and lipopolysaccharide (LPS) were observed. First, LPS activity was inhibited by antibodies to either TLR2 or TLR4, but not by antibodies to CD19, CD79b or CD38. Another was that LPS-induced B cell proliferation was inhibited by polymyxin B (PMB), a specific inhibitor of LPS, whereas AK activity was not affected. Taken together, our results demonstrate that AK directly activates B cells, but not T cells, and suggest that AK has a broader receptor profile than LPS in B cells.

Adjuvants, Immunologic↗
PubMed2003

Reductive dechlorination of TCE by zero valent bimetals.

Six zero valent bimetal combinations were tested for trichloroethene (TCE) dechlorination. Palladium, nickel, and copper were coated at 500 mg kg(-1) or less onto zero valent iron, producing Pd/Fe, Ni/Fe, and Cu/Fe bimetals, and zinc, producing Pd/Zn, Ni/Zn, and Cu/Zn bimetals. The order of reactivity of the six bimetals and two metals based on surface area normalized pseudo first order rate constants was observed to be: Pd/Fe > Pd/Zn > Ni/Fe > Cu/Fe > Ni/Zn > Cu/Zn > Fe > Zn. Thus, in general, 1) iron metal and bimetals exhibit faster reaction rates than the corresponding zinc reductants, 2) bimetals exhibit faster reaction rates than pure metals, and 3) metal coating enhance reactivity in the order of Pd > Ni > Cu. Chlorinated intermediate products were observed in small amounts for Fe only. In all cases, the chloride balance, calculated from TCE and chloride concentrations, ranged from 90 to 111%. The results are discussed in terms of the effects of bimetal combinations on catalytic dechlorination, prevention of nonreactive film and metal corrosion.

Chlorine Compounds↗
PubMed2003

Dechlorination of chlorinated ethenes and acetylenes by palladized iron.

The degradation of chlorinated ethenes and acetylenes by palladium coated iron was studied in batch experiments. The reactivity of palladium coated iron with tetrachloroethene and its less chlorinated ethene and acetylene derivatives showed that dechlorination rates increased as the number of chlorines decreased. Thus, vinyl chloride, the most toxic compound in the chlorinated ethenes, was most rapidly degraded by the palladium coated iron. This reactivity order is opposite to the results previously observed with plain zero valent metals. The major dechlorination products of trichloroethene were ethane, ethene, and acetylene and the carbon mass balance was found to be about 81-91%. No chlorinated products were detected indicating that multiple or concerted dechlorinations rather than sequential reactions were occurring on palladium coated iron. The proposed reaction pathway is that once the chlorinated ethenes have adsorbed on the metal surface, all the chlorines are removed before desorption without release of less chlorinated products such as dichloroethenes and vinyl chloride. As the palladium content increased from 0.025% to 0.77%, the reaction rate was increased. The reaction rate increased linearly up to 0.098% of palladium, however, the increasing rate diminished with higher amounts of Pd. Results of Energy Dispersive X-ray Spectroscopy showed that uneven palladium coatings were formed on the iron at high contents of palladium.

Chlorine↗
PubMed2003

Deep venous thrombosis associated with protein C and/or S deficiency: management with catheter-directed thrombolysis.

We performed this study to evaluate the efficacy of catheter-directed thrombolysis with urokinase in treating acute symptomatic iliofemoral deep venous thrombosis associated with protein C and/or S deficiency. A total of 42 consecutive patients with deep venous thrombosis were seen between September 2000 and August 2002. Of these, catheter-directed thrombolysis via the popliteal vein was performed in 5 patients (11.9%) with acute iliofemoral deep venous thrombosis associated with protein C and/or S deficiency. Average duration of symptoms was 4.2 days (range, 1-7 days). The average urokinase dose was 2.7 million IU (range, 0.6 million to 7.0 million IU) infused over an average of 33.1 h (range, 16-67 h). Lysis was complete in all five treated cases. Two cases had underlying iliac venous stenoses (>50%) that were treated with angioplasty and stent placement. In one patient in whom recanalization of a right iliac vein occlusion was successful, thrombosis occurred in the treated vein within 3 weeks of intervention despite full anticoagulation therapy, and further intervention was required. There were no complications or clinically detectable pulmonary emboli. The technical and clinical success rates were 100%. This initial experience suggests that catheter-directed thrombolysis for treatment of acute symptomatic iliofemoral deep venous thrombosis associated with protein C and/or S deficiency is safe and effective.

Acute Disease↗
PubMed2003

Sequential sorption and desorption of chlorinated phenols in organoclays.

Effect of pH on the sorption and desorption of the chlorinated phenols (2-chlorophenol and 2,4-dichlorophenol) in HDTMA-montmorillonite organoclays was investigated using sequential batch experiments. 2,4-dichlorophenol exhibited higher affinity in both sorption and desorption than 2-chlorophenol at pH 4.85 and 9.15. For both chlorophenols, the protonated speciation (at pH 4.85) exhibited a higher affinity in both sorption and desorption than the predominant deprotonated speciation (about 80% and 95% of 2-chlorophenate and 2,4-dichlophenate anions at pH 9.15, respectively). Desorption of chlorinated phenols was strongly dependent on the current pH regardless of their speciation during the previous sorption stage. No appreciable desorption resistance of the chlorinated phenols was observed in organoclays after sequential desorptions. Affinity of both chlorophenols in bisolute competitive sorption and desorption was reduced compared to that in a single-solute system due to the competition between solutes. The ideal adsorbed solution theory coupled with the single-solute Freundlich model successfully predicted the bisolute competitive sorption and desorption equilibria.

Adsorption↗
PubMed2002

Experimental and numerical studies on convective heat transfer in a neonatal incubator.

Thermo-neutrality is one of the major environmental factors affecting a premature or low-birth-weight neonate inside an incubator. Severe temperature differences inside an incubator lead to neonate heat loss, hypothermia and apnoea, which are closely related to air flow and air velocity. In the study, flow visualisations, hot-wire velocity measurements and computational fluid dynamics simulate the airflow inside a neonatal incubator. An anatomically correct neonate model is designed using a three-dimensional laser scanner system and a rapid prototyping machine. Flow visualisations demonstrate that large-scale rotating airflow is produced inside the chamber, and a number of small, stationary eddies are found in regions between the air inlet and the neonate. Hot-wire measurements show that air velocities along the long inlets are not uniform. Computational fluid dynamics show relatively uniform temperatures of about 34 degrees C on the neonate's anterior aspect and the highest temperature of 36.1 degrees C at the right armpit and the crotch. Flow fields from airflow visualisations, hot-wire measurements and computational fluid dynamics are very similar, both qualitatively and quantitatively. The small eddies produced between the neonate and the mattress could interfere with convective and evaporative heat transfers from the neonate. Therefore it is important to eliminate eddies around the neonate in future designs of neonatal incubators.

Body Temperature Regulation↗
PubMed2002

Increased risk of peristomal wound infection after percutaneous endoscopic gastrostomy in patients with diabetes mellitus.

BACKGROUND: Results of prospective studies on the effect of prophylactic antibiotics before percutaneous endoscopic gastrostomy are conflicting. Factors for increased risk of peristomal wound infection have not been clearly identified. AIM: To evaluate the incidence of complications of percutaneous endoscopic gastrostomy and to determine the predictors of wound infection. PATIENTS AND METHODS: Percutaneous endoscopic gastrostomy was performed on 134 patients in different disease groups between January 1996 and June 2000. Medical records were carefully reviewed for demographic data, indications for percutaneous endoscopic gastrostomy, use of prophylactic antibiotics, complications and comorbid conditions predisposing to wound infection. RESULTS: Of 134 patients, 22 (16.4%) developed complications after percutaneous endoscopic gastrostomy Wound infection, the most common complication, occurred in 19 patients (14.2%) and Pseudomonas aeruginosa was the most frequently isolated microorganism. In univariate analysis, non-malignant disease and diabetes mellitus were significantly associated with peristomal wound infection after percutaneous endoscopic gastrostomy. In multivariate analysis, only diabetes mellitus was an independent risk factor for the development of peristomal wound infection after percutaneous endoscopic gastrostomy (p = 0.035) CONCLUSIONS: Patients with diabetes mellitus have a higher risk of peristomal wound infection after percutaneous endoscopic gastrostomy.

Diabetes Complications↗
PubMed2002

Association between CYP2D6 genotype and tardive dyskinesia in Korean schizophrenics.

The CYP2D6 gene codes for human cytochrome P450 2D6 enzyme, which is responsible for the metabolism of many psychiatric drugs. In schizophrenic patients treated with neuroleptics, decreased or loss of function CYP2D6 alleles may contribute to the development of tardive dyskinesia (TD), a movement disorder that frequently occurs with chronic neuroleptic treatment. The goal of this study was to determine whether the occurrence of TD is associated with CYP2D6 genotype in a cohort of Korean schizophrenics by employing a CYP450 GeneChip((R)) oligonucleotide microarray and PCR assays to screen for 19 CYP2D6 alleles. Our results revealed that males with at least one decreased or loss of function allele have a moderately greater chance of developing TD than males with only wild-type alleles. Female schizophrenics did not have a significantly greater chance of developing TD. Our results demonstrate the utility of CYP2D6 microarrays to assess genotype status in this Korean cohort.

Adolescent↗
PubMed2002

Long-term stress and Helicobacter pylori infection independently induce gastric mucosal lesions in C57BL/6 mice.

BACKGROUND: Long-term psychological stresses may have a role in the pathogenesis of peptic ulcer. However, the interaction between stress and Helicobacter pylori infection in the development of peptic ulcer is not established. The aim of this study was to elucidate the roles of long-term stress and H. pylori infection in the development of gastric mucosal lesions in mice. METHODS: The Sydney strain (SS1) of H. pylori was inoculated into the stomach of C57BL/J6 mice. Twelve weeks later, mice with or without H. pylori infection were exposed to long-term repeated water-immersion-restraint stress (WIRS) for 12 h per day, 3 times per week, for 8 weeks. Gastric mucosal lesions were evaluated both macroscopically (ulcer index) and microscopically (Updated Sydney System). RESULTS: The long-term WIRS induced mild inflammation, oedema, interstitial haemorrhage and superficial erosions in the stomach of mice both with and without H. pylori infection. The degree of mucosal inflammation or atrophy in H. pylori-infected mice was not influenced by the stress. In the mice without H. pylori infection, the ulcer index of the stressed mice was greater than that of non-stressed mice (1.66 +/- 0.39 versus 0.17 +/- 0.08, P = 0.007). In the mice with H. pylori infection, the ulcer index (mean +/- s(x)) of the stressed mice was also greater than that of non-stressed mice (2.31 +/- 0.59 versus 0.64 +/- 0.22, P = 0.027). CONCLUSIONS: The present study showed that long-term stress can induce gastric mucosal inflammation and erosions, and this effect may occur independently of H. pylori infection.

Animals↗