Soo-Han Lee

Konkuk University, Sŏul, Seoul, South Korea

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Publications (7)37.41 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This study aimed to characterize pharmacodynamic interaction between propofol and aminophylline. Nine beagle dogs were randomly allocated at the propofol rates of 0.75 (group A), 1.00 (group B), and 1.25 (group C) mg/kg/min. During period 1, propofol only was infused, while during period 2, aminophylline only, at the rate of 0.69 (group A), 1.37 (group B), and 2.62 (group C) mg/kg/h. During periods 3-5, the two drugs were co-administered. The aminophylline infusion rate was 0.69 (period 3), 1.37 (period 4), and 2.62 (period 5) mg/kg/h. The aminophylline was infused from 0 to 30 h, and the propofol was infused at 24 h for 20 min. Blood samples and electroencephalograms were obtained at preset intervals. In the linear regression between log-transformed doses of aminophylline and AUC inf , the slope was 0.6976 (95 % CI 0.5242-0.8710). Pharmacokinetics of aminophylline was best described by a one-compartment, with enzyme auto-induction, model. Pharmacokinetics and pharmacodynamics of propofol were best described by a three-compartment model and a sigmoid E max model, respectively. Pharmacodynamic parameter estimates of propofol were: k e0 = 0.805/min, E 0 = 0.76, E max = 0.398, Ce 50 na = 2.38 μg/mL (without aminophylline-exposure), Ce 50 wa = 4.49 μg/mL (with aminophylline-exposure), and γ = 2.21. Propofol becomes less potent when exposed to aminophylline. Pharmacodynamic antagonistic interaction of aminophylline with propofol sedation, may occur, not in a dose-dependent manner, but in an all-or-none response.
    Journal of Pharmacokinetics and Pharmacodynamics 08/2014; · 1.81 Impact Factor
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    ABSTRACT: This study identified specific and avid RNA aptamers consisting of 2'-hydroxyl or 2'-fluoro pyrimidines against hepatitis C virus (HCV) NS5B replicase, an enzyme that is essential for HCV replication. These aptamers acted as potent decoys to competitively impede replicase-catalyzed RNA synthesis activity. Cytoplasmic expression of 2'-hydroxyl aptamer efficiently inhibited HCV replicon replication in human liver cells through specific interaction with, and sequestration of, the target protein without either off-target effects or escape mutant generation. Selected 2'-fluoro aptamer could be truncated up to chemically manufacturable length of 29 nt with increase in the affinity to HCV NS5B. Noticeably, transfection of the minimized aptamer efficiently suppressed HCV replication in cells without escape mutant appearance. The aptamer was further modified through conjugation of cholesterol or galactose-polyethylene glycol ligand for in vivo availability and liver specific delivery. The conjugated aptamer efficiently entered cells and inhibited genotype 1b sub-genomic and genotype 2a full length HCV JFH-1 RNA replication without toxicity and innate immunity induction. Importantly, a therapeutically feasible amount of the conjugated aptamer was delivered in vivo to liver tissue in mice. Therefore, cytoplasmic expression of 2'-hydroxyl aptamer or direct administration of chemically synthesized and ligand-conjugated 2'-fluoro aptamer against HCV NS5B could be a potent anti-HCV approach.
    Journal of Virology 04/2013; · 5.08 Impact Factor
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    ABSTRACT: Carcinoembryonic antigen (CEA) is expressed by many types of cancer cells; its overexpression induces cell adhesion, increases resistance to anoikis, and promotes hepatic metastasis of colon cancer cells. The amino acid sequence PELPK in its hinge region, between the N and A1 domains, is required for migration of cancer cells to the liver. We sought to identify ligands of this domain for use in diagnosis and therapy. We screened for RNA aptamers against the domain of CEA required for metastasis using systematic evolution of ligands by exponential enrichment. The specificity and affinity of the aptamer for CEA protein were characterized by mobility shift, uptake, and surface plasmon resonance assays. We analyzed the effects of the aptamer on metastatic properties of cells, as well as metastasis of colon cancer cells in mice. Using systematic evolution of ligands by exponential enrichment, we identified an RNA aptamer that bound to the PELPK sequence in CEA with high affinity and specificity. The isolated aptamer bound specifically to CEA-positive cells and inhibited interactions between CEA and heterogeneous nuclear ribonucleoprotein M4. The aptamer inhibited homotypic aggregation, migration, and invasion by CEA-positive cancer cells, but did not affect adhesion of endothelial cells. The aptamer induced colon cancer cell anoikis by interrupting the interaction between death receptor 5 and CEA. The aptamer prevented metastasis of human colon cancer cells to the livers of mice. An RNA aptamer that binds to the PELPK sequence in CEA inhibits its interactions with heterogeneous nuclear ribonucleoprotein M4 and death receptor 5, migration and invasion by colon cancer cells, and hepatic metastasis of colon cancer cells in mice. It promoted cancer cell anoikis and might be used to identify CEA-positive tumors in patients or be developed as an anti-cancer reagent.
    Gastroenterology 03/2012; 143(1):155-65.e8. · 12.82 Impact Factor
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    ABSTRACT: • Remifentanil, an intravenous ultra short-acting opioid, depresses central nervous system activity with an increase in the delta band power, and causes beta activation after discontinuation, resulting in a rebound of the processed electroencephalographic parameters, including 95% spectral edge frequency, the canonical univariate parameter and electroencephalographic approximate entropy. • A sigmoid Emax model, in which the highest predicted values of processed electroencephalographic parameters are restricted to the baseline value, cannot describe a rebound of these parameters. • Electroencephalographic approximate entropy correlated well with the remifentanil blood concentration and demonstrated high baseline stability. • A combined effect and tolerance model effectively characterized the time course of the remifentanil effect on the central nervous system, including the rebound which occurred during recovery from the remifentanil effect. • Temporal linear mode complexity was comparable with approximate entropy as a univariate electroencephalographic descriptor of the effect of remifentanil on the central nervous system. AIMS Previously, electroencephalographic approximate entropy (ApEn) effectively described both depression of central nervous system (CNS) activity and rebound during and after remifentanil infusion. ApEn is heavily dependent on the record length. Linear mode complexity, which is algorithmatically independent of the record length, was investigated to characterize the effect of remifentanil on the CNS using the combined effect and tolerance, feedback and sigmoid E(max) models. METHODS The remifentanil blood concentrations and electroencephalographic data obtained in our previous study were used. With the recording of the electroencephalogram, remifentanil was infused at a rate of 1, 2, 3, 4, 5, 6, 7 or 8 µg kg(-1) min(-1) for 15-20 min. The areas below (AUC(effect) ) or above (AAC(rebound) ) the effect vs. time curve of temporal linear mode complexity (TLMC) and ApEn were calculated to quantitate the decrease of the CNS activity and rebound. The coefficients of variation (CV) of median baseline (E(0)), maximal (E(max)), and individual median E(0) minus E(max) values of TLMC were compared with those of ApEn. The concentration-TLMC relationship was characterized by population analysis using non-linear mixed effects modelling. Median AUC(effect) and AAC(rebound) were 1016 and 5.3 (TLMC), 787 and 4.5 (ApEn). The CVs of individual median E(0) minus E(max) were 35.6, 32.5% (TLMC, ApEn). The combined effect and tolerance model demonstrated the lowest Akaike information criteria value and the highest positive predictive value of rebound in tolerance. The combined effect and tolerance model effectively characterized the time course of TLMC as a surrogate measure of the effect of remifentanil on the CNS.
    British Journal of Clinical Pharmacology 01/2011; 71(6):871-85. · 3.69 Impact Factor
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    ABSTRACT: To evaluate the incidence and severity of injection pain caused by microemulsion propofol and lipid emulsion propofol in relation to plasma bradykinin generation and aqueous free propofol concentrations. Injection pain was evaluated in 147 patients. Aqueous free propofol concentrations in each formulation, and in formulation mixtures containing agents that reduce propofol-induced pain, were measured by high-performance liquid chromatography. Plasma bradykinin concentrations in both formulations and in their components mixed with blood sampled from six volunteers were measured by radioimmunoassays. Injection pain caused by 8% polyethylene glycol 660 hydroxystearate (PEG660 HS) was evaluated in another 10 volunteers. The incidence of injection pain [visual analogue scale (VAS) >30 mm] caused by microemulsion and lipid emulsion propofol was 69.7 and 42.3% (P < 0.001), respectively. The median VAS scores for microemulsion and lipid emulsion propofol were 59 and 24 mm, respectively (95% confidence interval for the difference 12.5, 40.0). The aqueous free propofol concentration of microemulsion propofol was seven times higher than that of lipid emulsion propofol. Agents that reduce injection pain did not affect aqueous free propofol concentrations. Microemulsion propofol and 8% PEG660 HS enhanced plasma bradykinin generation, whereas lipid emulsion propofol and lipid solvent did not. PEG660 HS did not cause injection pain. Higher aqueous free propofol concentrations of microemulsion propofol produce more frequent and severe pain. The plasma kallikrein-kinin system may not be involved, and the agents that reduce injection pain may not act by decreasing aqueous free propofol concentrations.
    British Journal of Clinical Pharmacology 12/2008; 67(3):316-25. · 3.69 Impact Factor
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    ABSTRACT: A newly developed microemulsion propofol consisted of 10% purified poloxamer 188 and 0.7% polyethylene glycol 660 hydroxystearate. The authors studied the physicochemical properties, aqueous free propofol concentration, and plasma bradykinin generation. Pharmacokinetics and pharmacodynamics were also evaluated in rats. The pH, particle size, and osmolarity of microemulsion propofol were measured using a pH meter, particle size analyzer, and cryoscopic osmometer, respectively. The aqueous free propofol and plasma bradykinin were measured by a dialysis method and radioimmunoassay, respectively. Microemulsion propofol was administered by zero-order infusion of 0.5, 1.0, and 1.5 mg . kg . min for 20 min in 30 rats. The electroencephalographic approximate entropy was used as a surrogate measure of propofol effect. The pH, osmolarity, and particle size of microemulsion propofol are 7.5, 280 mOsm/l, and 67.0 +/- 28.5 nm, respectively. The aqueous free propofol concentration in microemulsion propofol was 63.3 +/- 1.2 mug/ml. When mixed with human blood, microemulsion propofol did not generate bradykinin in plasma. Although microemulsion propofol had nonlinear pharmacokinetics, a two-compartment model with linear pharmacokinetics best described the time course of the propofol concentration as follows: V1 = 0.143 l/kg, k10 = 0.175 min, k12 = 0.126 min, k21 = 0.043 min. The pharmacodynamic parameters in a sigmoid Emax model were as follows: E0 = 1.18, Emax = 0.636, Ce50 = 1.87 mug/ml, gamma = 1.28, ke0 = 1.02 min. Microemulsion propofol produced a high concentration of free propofol in the aqueous phase. For the applied dose range, microemulsion propofol showed nonlinear pharmacokinetics.
    Anesthesiology 10/2008; 109(3):436-47. · 5.16 Impact Factor
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    ABSTRACT: The aim of this trial was to evaluate the induction and recovery characteristics of microemulsion propofol (Aquafol; Daewon Pharmaceutical Co., Ltd., Seoul, Korea). Pharmacokinetics, pharmacodynamics, and safety profile were investigated. Lipid emulsion propofol (Diprivan; AstraZeneca, London, United Kingdom) was used as a comparator. Thirty-one healthy volunteers aged 20-79 yr were given an intravenous bolus of propofol 2 mg/kg, followed by variable rate infusion for 60 min. Each volunteer was studied twice with different formulations at an interval of 1 week. Arterial concentrations of propofol were measured, and Bispectral Index was used as a surrogate measure of propofol effect. The induction and recovery characteristics including bioequivalence were evaluated by noncompartmental analysis. The pharmacokinetics and pharmacodynamics were investigated using a population approach with mixed effects modeling. The rate, severity, and causal relation of adverse events were analyzed. Both formulations were bioequivalent. The observed time to peak effect after a bolus of both formulations was 1.5 min. Plasma concentration of propofol at loss of consciousness, time to loss of consciousness after a bolus, and time to recovery of consciousness after discontinuation of infusion did not show significant differences. The population pharmacokinetics and pharmacodynamics revealed a variety of differences between two formulations. Aquafol showed similar safety profile to Diprivan. The efficacy and safety of Aquafol were not different from those of Diprivan within the dose range in this study.
    Anesthesiology 06/2007; 106(5):924-34. · 5.16 Impact Factor

Publication Stats

76 Citations
37.41 Total Impact Points

Institutions

  • 2014
    • Konkuk University
      • College of Veterinary Medicine
      Sŏul, Seoul, South Korea
  • 2008–2011
    • Ulsan University Hospital
      Urusan, Ulsan, South Korea
  • 2007
    • Inje University Paik Hospital
      Sŏul, Seoul, South Korea