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Biomedical subjects

H S Moon

Publications and source records attributed to H S Moon.

At least 19 recordsLinked to original sources
PubMed2006

Sweep optical frequency synthesizer with a distributed-Bragg-reflector laser injection locked by a single component of an optical frequency comb.

A sweep optical frequency synthesizer is demonstrated by using a frequency-stabilized optical frequency comb and injection-locked distributed-Bragg-reflector (DBR) laser diode. The injection-locked DBR laser acts as a single-frequency filter and, simultaneously, a high-gain amplifier of the optical frequency comb. The frequency instability of the heterodyne beat signal between two independently injection-locked DBR lasers is measured to be 2.3 x 10(-16) at 1 s averaging time. The output frequency of the sweep optical frequency synthesizer can be precisely tuned over 1 GHz, and a saturated absorption spectrum of the Cs D2 line at 852 nm is recorded by the injected DBR laser.

Journal Article↗
PubMed2006

Down-regulation of PPARgamma2-induced adipogenesis by PEGylated conjugated linoleic acid as the pro-drug: Attenuation of lipid accumulation and reduction of apoptosis.

This study is designed to evaluate whether the PEGylated conjugated linoleic acid (PCLA) as the pro-drug can have favorable stability, bioavailability, and anti-adipogenic activity in 3T3-L1 cells for anti-obesity when compared with conjugated linoleic acid (CLA) itself. The CLA was simply coupled to poly(ethylene glycol) (PEG) at the melting state without solvents or catalysts through ester linkages between the carboxylic group of CLA and the hydroxyl group of PEG. To confirm of PCLA as the pro-drug, CLA release from PCLA was investigated by using high-performance liquid chromatographic (HPLC), showing that CLA release from PCLA was almost 90% in a nearly continuous fashion over the next 75h. Apoptosis was promoted by both CLA- and PCLA-treatments with increasing concentrations. However, the level of cell apoptosis induced by PCLA was lower than that induced by CLA owing to the biocompatible and hydrophilic properties of PEG. Moreover, the PCLA decreased glycerol-3-phosphate dehydrogenase (GPDH) activity in 3T3-L1 cells by acting upon major adipocyte marker proteins such as PPARgamma2, C/EBPalpha, and aP2 modulators. Furthermore, either CLA or PCLA stimulated basal, but not isoproterenol-sensitive, lipolysis in our cell model, suggesting that both CLA and PCLA may stimulate lipolysis via hormone sensitive lipase (HSL)-independent mechanisms. These results suggest that the PCLA may prove to be a stable pro-drug to control the deposition of fat in the human body, and that the anti-adipogenic effect of the PCLA on 3T3-L1 cells will offer a challenging approach for anti-obesity.

3T3-L1 Cells↗
PubMed2006

Regulation of adipocyte differentiation by PEGylated all-trans retinoic acid: reduced cytotoxicity and attenuated lipid accumulation.

Obesity is major risk factor for many disorders, including diabetes, hypertension and heart disease. Unfortunately, there is a dearth of therapeutic agents available to clinicians for the treatment of obesity. The principal aim of this study was to investigate whether PEGylated all-trans retinoic acid (PRA) can have favorable stability and biological activity in 3T3-L1 preadipocytes as an antiobesity drug. Here, we found that PRA inhibits the process of adipogenesis, including survival of adipocytes and differentiation to mature adipocytes. The results showed that RA nanoparticles (NPs) were prepared by PEGylation; below 200 nm, PRA-NPs were obtained. Moreover, PRA decreased glycerol-3-phosphate dehydrogenase activity in 3T3-L1 preadipocytes by acting with major adipocyte marker proteins such as PPARgamma2, C/EBPalpha and aP2 modulators. Apoptosis, in addition, increased as the level of RA increased from 10 to 20 microM, whereas PRA reduced apoptosis with increasing concentrations. Our data suggest that PRA-NP has potential as an antiobesity drug carrier due to its small particle size and PEGylated core-shell structure. In addition, our results suggest that PRA inhibits the process of adipogenesis and may be developed to treat obesity. Based on these results, PRA is suitable for adipocyte studies, and an enhanced effect of PRA with adipocyte differentiation offers a challenging approach for pharmaceutical applications.

3T3 Cells↗
PubMed2006

Determination of biodegradation potential by two culture-independent methods in PAH-contaminated soils.

Biodegradation potentials of polycyclic aromatic hydrocarbons (PAHs) were determined with soil samples collected from various depths of a PAH-contaminated site and of a site nearby where PAHs were not found. Putative dioxygenase genes were amplified by a primer set specific for initial dioxygenases and identified by web-based database homology search. They were further categorized into several groups of which four dioxygenases were selected as probes for DNA hybridization. The hybridization signals according to the presence of putative dioxygenases were positively related to the extent of PAH contamination. However, the signal intensities varied depending on the probes hybridized and moreover were not consistent with PAH biodegradation activities determined by CO2 evolution. Despite widely accepted advantages of molecular biodegradation assessment, our data clearly present the variations of assessment results depending on the genetic information used and suggest that the methodology may tend to underestimate the real biodegradation capacity of a site probably due to the limited dioxygenase database available at the moment. Therefore, the molecular assessment of biodegradation potential should involve a very careful primer and probe design and an extensive microbiological examination of a site of interest to accurately delineate the biodegradation potential of the site.

Amino Acid Sequence↗
PubMed2004

Rapid in vitro adventitious shoot propagation of Scopolia parviflora through rhizome cultures for enhanced production of tropane alkaloids.

A rapid micropropagation system for Scopolia parviflora Nakai (Solanaceae), a rare medicinal plant native to Korea, was established using rhizome cultures. Shoots that originated from adventitious shoots of the rhizome were multiplied when the rhizomes were cultured on half-strength B5 liquid medium supplemented with various growth regulators. Optimum shoot multiplication was observed in half-strength B5 medium containing 3% (w/v) sucrose and 5.77 microM gibberellic acid (GA(3)). Each rhizome gave rise to an average of 12 shoots. Shoot elongation and root induction from multiple shoots occurred on growth regulator-free half-strength B5 solid medium. Healthy plantlets were transferred to a peat moss:vermiculite mixture for acclimatization, which was successful. The concentrations of tropane alkaloids, hyoscyamine and scopolamine were determined in different tissues of native growing plants, in vitro-propagated plants and acclimatized plants by high-performance liquid chromatography. The analysis revealed that the levels of hyoscyamine and scopolamine were higher in in vitro-propagated plants than in the native growing plants. When the rhizome was cut into segments and transferred to optimal culture conditions for multiple shoot propagation, only 12 weeks were required to produce a mature plant. We conclude that in vitro propagation techniques through rhizome cultures provide an efficient and rapid method for shoot propagation of S. parviflora.

Atropine↗
PubMed2004

The three-dimensional microstructure of the trabecular bone in the mandible.

This study investigated the three dimensional (3D) trabecular microstructure of the alveolar and basal bone in the mandible using micro-CT and compared the morphometric values of the different sites. Ten specimens were prepared and scanned using a micro-CT system. Both the alveolar and basal trabecular bone of the premolar region in the mandible were measured for the structural analysis. Cross-sectional 1024x1024 pixel images were created. From the two-dimensional (2D) images produced, 3D structural images were reconstructed. After scanning the specimen, the volumes of interest (VOI) of the alveolar and basal bone regions were selected from the 3D reconstruction images, and the structural parameters such as bone volume fraction, bone surface density, trabecular thickness, trabecular separation, trabecular number and structural model index were analyzed. The trabecular structure showed a marked variation within the sites of the specimen, especially in the basal trabecular bone inferior to the mandibular canal. In both the alveolar and basal bone regions, a mixture of both plate-like and rod-like structures was observed. The alveolar region showed a more compact, plate-type trabecular structure than the basal regions. In parametric comparison with the basal bone, the alveolar bone generally had a higher bone volume fraction, bone trabecular thickness and trabecular number, and lower bone surface density, trabecular separation and structural model index. The alveolar bone consisted of a compact bone structure with a large amount of thick plate-type trabecular bone, which was effectively resistant to the masticatory forces. As the measurements were made closer to the basal bone, a loose structure was observed with lower bone volume and fewer, thin, rod-like trabeculae.

Adult↗
PubMed2004

Use of autotrophic sulfur-oxidizers to remove nitrate from bank filtrate in a permeable reactive barrier system.

This study was conducted to evaluate the potential applicability of an in situ biological reactive barrier system to treat nitrate-contaminated bank filtrate. The reactive barrier consisted of sulfur granules as an electron donor and autotrophic sulfur-oxidizing bacteria as a biological component. Limestone was also used to provide alkalinity. The results showed that the autotrophic sulfur oxidizers were successfully colonized on the surfaces of the sulfur particles and removed nitrate from synthetic bank filtrate. The sulfur-oxidizing activity continuously increased with time and then was maintained or slightly decreased after five days of column operation. Maximum nitrate removal efficiency and sulfur oxidation rate were observed at near neutral pH. Over 90% of the initial nitrate dissolved in synthetic bank filtrate was removed in all columns tested with some nitrite accumulation. However, nitrite accumulation was observed mainly during the initial operation period, and the concentration markedly diminished with time. The nitrite concentration in effluent was less than 2 mg-N/l after 12 days of column operation. When influent nitrate concentrations were 30, 40, and 60 mg-N/l and sulfur content in column was 75%, half-order autotrophic denitrification reaction rate constants were 31.73 x 10(-3), 33.3 x 10(-3), and 36.4 x 10(-3) mg(1/2)/l(1/2)min, respectively. Our data on the nitrate distribution profile along the column suggest that an appropriate wall thickness of a reactive barrier for autotrophic denitrification may be 30 cm when influent nitrate concentration is less than 60 mg-N/l.

Hydrogen-Ion Concentration↗
PubMed2002

Gamma-interferon and soluble interleukin 2 receptor in tuberculous pleural effusion.

To analysis the difference between systemic and local pleural T cell response in pulmonary tuberculosis, we analyzed interferon (IFN)-gamma and soluble interleukin-2 receptor (sIL-2R) in peripheral blood mononuclear cells (PBMC) culture supernatants and in pleural effusion (PE). We also investigated the association of pleural INF-gamma and sIL-2R levels with development of residual pleural thickening (RPT). The subjects in this study included patients with active pulmonary tuberculosis with or without PE (n = 46), those with nontuberculous PE (n = 32), and healthy tuberculin reactors (n = 20). Measurement of IFN-gamma and sIL-2R were made by ELISA. In pulmonary tuberculosis, IFN-gamma and sIL-2R concentrations in PBMC culture supernatants were lower than those of healthy tuberculin reactors (IFN-gamma; 258.4 +/-111.5 pg/mL versus 2792.5 +/-633.2 pg/mL, sIL-2R; 1465.0 +/-144.4 pg/mL versus 4777.1 +/-178.5 pg/mL, p < 0.05), whereas IFN-gamma and sIL-2R concentrations in PE were higher than those from nontuberculous pleural effusion (IFN-gamma; 1154.4 +/-252.4 pg/mL versus 292.0 +/-68.9 pg/mL, sIL-2R; 9805.2 +/-978.9 pg/mL versus 3426.7 +/-695.6 g/mL, p < 0.05). IFN-gamma and sIL-2R in PBMC culture supernatants were significantly lower in tuberculat patients with PE than those without PE, and the patients with a high value of IFN-gamma or sIL-2R in PE showed a low value of IFN-gamma or sIL-2R in PBMC culture supernatant, respectively. Patients with RPT had significantly higher IFN-gamma and sIL-2R values in their PE compared with those without RPT. These findings suggest that diminished systemic Th1 response in tuberculosis results from the accumulation of activated Th1 cell to the disease site, and that levels of IFN-gamma and sIL-2R in PE are useful posttreatment markers of RPT.

Adolescent↗
PubMed2002

Relation of airway reactivity and sensitivity with bronchial pathology in asthma.

Airway hyperresponsiveness in asthmatics, which may result from inflammation or remodeling, is expressed as the concentration of methacholine that causes a 20% fall in FEV1 in the concentration-response curve (PC20). A decrease in PC20 may be due to a steeper curve (hyperreactivity) and/or a curve shift to the left (hypersensitivity). Our purpose was to analyze the relation of airway sensitivity and reactivity to airway pathological changes. The PC6, as sensitivity parameter, and the slope between PC20 and PC40 as reactivity parameter, were calculated. Total and differential cell counts in the bronchoalveolar lavage fluid, and percentage of epithelial shedding, basement membrane thickness, and submucosal thickness on bronchial biopsy, were measured. The PC6 showed a correlation with the baseline FEV1%. The slope was significantly correlated with the basement membrane thickness, and also demonstrated a strong association with submucosal thickness. The PC20 showed a correlation with the baseline FEV1% and the degree of epithelial shedding. These results suggest that the airway sensitivity and reactivity measurements reflect the degree of airway caliber and remodeling, respectively.

Adolescent↗
PubMed2001

Synthesis and biological evaluation of myoseverin derivatives: microtubule assembly inhibitors.

Myoseverin, a trisubstituted purine, inhibits microtubule assembly in vitro, interferes with normal mitotic spindle assembly, and arrests the cell cycle in mitosis in U937 cells. We synthesized a variety of myoseverin derivatives and screened them for inhibition of spindle assembly in Xenopus egg extracts and for microtubule disassembly in vitro. Selected compounds were tested against 60 cancer cell lines at the National Cancer Institute as possible anticancer drug candidates.

Animals↗
PubMed2001

Expression and tyrosine phosphorylation of E-cadherin, beta- and gamma-catenin, and epidermal growth factor receptor in cervical cancer cells.

OBJECTIVES: The cadherin/catenin adhesion complex is fundamentally involved in epithelial cancer invasion and metastasis. Much evidence suggesting that epidermal growth factor (EGF) induced the scattering and invasion of cancer cells, probably by affecting E-cadherin function, has been reported. The present study aimed to confirm the hypothesis that EGF/epidermal growth factor receptor (EGFR) was related with the E-cadherin adhesion system in cervical cancer cells and that EGF might induce tyrosine phosphorylation of beta- and gamma-catenin. METHODS: Cervical cancer cells were treated for different time durations with 30 ng/ml of EGF. Alteration of the cell morphology was examined by light microscopy and the expression of E-cadherin, beta-catenin, gamma-catenin, EGFR, and activated EGFR was assayed using Western blotting. Tyrosine phosphorylation of beta- and gamma-catenin was also examined using immunoprecipitation. RESULTS: E-cadherin and EGFR were expressed in CaSki, HT-3, and ME-180 cell lines, which showed epithelial contact growth. The expression of E-cadherin and beta- and gamma-catenin did not change after treatment with EGF. The expression of EGFR decreased and activated EGFR expression increased in 30 min and then decreased subsequently. The simultaneous expression of activated EGFR and tyrosine phosphorylation of beta- and gamma-catenin was found. CONCLUSIONS: EGF-induced scattering of the E-cadherin-positive cervical cancer cells might be the result of tyrosine phosphorylation of the beta- and gamma-catenin. Phosphorylation of the beta- and gamma-catenin may hamper the adhesive function of the E-cadherin-catenin complex.

Blotting, Western↗
PubMed2001

Attenuation of Zn2+ neurotoxicity by aspirin: role of N-type Ca2+ channel and the carboxyl acid group.

Synaptically released Zn2+ ions enter into neurons primarily through voltage-gated Ca2+ channels (VGCC) or N-methyl-d-aspartate (NMDA) receptors, which can mediate pathological neuronal death. We studied the possibility (and underlying mechanisms) that aspirin, known to prevent NMDA neurotoxicity, would also attenuate Zn2+ neurotoxicity. Administration of 3 to 10 mM aspirin, in cortical cell cultures, attenuated the evolution of neuronal death following exposure to 300 microM Zn2+ for 30 min. This neuroprotective effect of aspirin was attributable to the prevention of Zn2+ ion entry. Aspirin interfered with inward currents and an increase in [Ca2+]i through VGCC and selective binding of omega-conotoxin, sensitive to N-type Ca2+ channel. The omega-conotoxins GVIA or MVIIC, the selective inhibitors of N-type Ca2+ channels, attenuated Zn2+ neurotoxicity. Aspirin derivatives lacking the carboxyl acid group did not reduce Zn2+ neurotoxicity. The present findings suggest that aspirin prevents Zn2+-mediated neuronal death by interfering with VGCC, and its action specifically requires the carboxyl acid group.

Acetylcysteine↗
PubMed2001

The mechanism of action of coculture on embryo development in the mouse model: direct embryo-to-cell contact and the removal of deleterious components.

OBJECTIVE: To elucidate the mechanism for the mode of action of coculture by the use of a coculture system for mouse one-cell embryos with human oviductal epithelial cells. DESIGN: Prospective, controlled in vitro experimental study. SETTING: Academic research laboratory. ANIMAL(S): Female ICR strain mice aged between 6 and 8 weeks. INTERVENTION(S): Flushed one-cell embryos were cultured in human tubal fluid medium alone (control), in coculture system with human oviductal cells, in five kinds of conditioned media, and in a contactless coculture system using a cell-culture insert. MAIN OUTCOME MEASURE(S): The percentage of the embryos developed to hatching blastocyst stage and the level of superoxide anion in the supernatant from each culture condition. RESULT(S): The rates of embryo development to the hatching blastocyst stage were significantly higher in the coculture group (43%) than in the control group (none) (P <.05). The embryo development rate in the control group was similar to that of the embryos in the five kinds of conditioned media. The effects of coculture on embryo development disappeared in the contactless coculture group. The level of superoxide anion was significantly reduced in the coculture group compared to the control group. CONCLUSION(S): The present coculture system overcomes the two-cell block in vitro and improves the embryo development. The beneficial effect may be a result of direct cell-to-cell contact between the embryo and helper cells and the removal of deleterious components from medium, rather than a result of embryotrophic factors.

Animals↗
PubMed2001

Distribution and cytokine production of CD4 and CD8 T-lymphocyte subsets in patients with acute asthma attacks.

BACKGROUND: The activation of T cells and the elevation of Th2-type cytokines have been observed in asthmatic patients, but the relative role of CD4 and CD8 T cell is still unclear. OBJECTIVE: To investigate the role of T cell subset in patients with acute asthma attacks, we analyzed the distribution, activation status, and cytokine production of CD4 and CD8 cells. METHODS: The percentages of the CD4 and CD8 cell in peripheral blood (PB) and bronchoalveolar lavage (BAL) fluid were analyzed by flow cytometry. The cytokines (IL-4, IL-5, and IFN-gamma) and soluble IL-2 receptor (sIL-2R) were measured by ELISA in culture supernatants of CD4 and CD8 cells purified from PB. RESULTS: The CD4/CD8 ratio in PB of asthmatic patients was significantly higher than that of controls, which was significantly reduced after treatment. In contrast, there was a tendency to high percentage of CD8 cells in asthmatic patients as compared with controls in BAL, which resulted in a decreased CD4/CD8 ratio. Comparing the T cell subsets in BAL with paired PB in asthma, the CD4 cells were higher in PB, but CD8 cells were higher in BAL. The IL-4, IL-5, and sIL-2R produced by CD4 cells were significantly higher than those produced by CD8 cells in asthmatic patients. CONCLUSIONS: Our results provide evidence that activated CD4 T cells increase and produce type 2 cytokines in PB, but CD8 T cell are more sequestrated than CD4 T cells in the airway during an acute asthma attack.

Acute Disease↗
PubMed2001

Interleukin-1beta regulates urokinase plasminogen activator (u-PA), u-PA receptor, soluble u-PA receptor, and plasminogen activator inhibitor-1 messenger ribonucleic acid expression in cultured human endometrial stromal cells.

The interleukin-1 (IL-1) system plays an integral role in local intercellular interactions during implantation. In addition, the plasminogen activator system, especially urokinase plasminogen activator (u-PA), plasminogen activator inhibitor (PAI-1), and u-PA receptor (u-PAR), are crucial during embryo implantation. Decidualization and implantation are complex processes dependent upon several proteases, including u-PA, and IL-1 is known to affect PA activity in several cell types. We investigated the role of IL-1beta in regulating u-PA, PAI-1, u-PAR, and soluble u-PAR messenger ribonucleic acid (mRNA) expression in cultured human endometrial stromal cells using quantitative competitive PCR. For confirmation of the mRNA data, we measured PAI-1 and u-PAR protein by enzyme-linked immunosorbent assay. Confluent stromal cell cultures treated with progesterone and estradiol for 9 days were stimulated with IL-1beta, and IL-1beta plus IL-1beta antibody for an additional 24 h. Total RNA was extracted, reverse transcribed, and coamplified using quantitative and competitive PCR with internal standards. IL-1beta increased PAI-1, u-PAR, and soluble u-PAR expression in a dose-dependent manner, and this result was reversed by anti-IL-1beta antibody treatment. u-PA mRNA expression was not dependent on IL-1beta. These results suggest that IL-1 may be important in regulating PAI-1 and u-PAR during stromal cell decidualization before implantation.

Binding, Competitive↗
PubMed2000

Effects of tumor necrosis factor-alpha and interferon-gamma on expressions of matrix metalloproteinase-2 and -9 in human bladder cancer cells.

We have investigated the effects of tumor necrosis factor-alpha (TNF-alpha) and interferon (INF-gamma), the potent Bacillus Calmette-Guerin (BCG)-induced cytokines on the production of MMP-2, MMP-9, TIMP-1, TIMP-2 and MT1-MMP in high grade human bladder cancer cell lines, T-24, J-82 and HT-1376 cell lines. MMP-2 expression and activity were decreased in T-24 cells treated with both cytokines in a dose dependent manner. However, J-82 cells treated with TNF-alpha and INF-gamma revealed dose dependent increases of MMP-9 expression and activity with similar baseline expression and activity of MMP-2. HT-1376 cells after exposure to TNF-alpha only enhanced the expression and activity of MMP-9. These results indicate that TNF-alpha and INF-gamma could regulate the production of MMP-2 or MMP-9 on bladder cancer cells and their patterns of regulation are cell specific. Furthermore, this diverse response of bladder cancer cells to TNF-alpha and INF-gamma suggests that BCG immunotherapy may enhance the invasiveness of bladder cancer in certain conditions with induction of MMPs.

Dose-Response Relationship, Drug↗