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Hwaseong, South Korea

Jang J.,Korea University | Hong S.-H.,Hanmi Research Center | Kim I.-H.,Korea University
Journal of Microbiology and Biotechnology | Year: 2011

A method for the rapid detection and quantification of Newcastle disease virus (NDV) produced in an animal cell culture-based production system was developed to enhance the speed of the NDV vaccine manufacturing process. A SYBR Green I-based real-time RT-PCR was designed with a conventional, inexpensive RT-PCR kit targeting the F gene of the NDV LaSota strain. The method developed in this study was validated for specificity, accuracy, precision, linearity, limit of detection (LOD), limit of quantification (LOQ), and robustness. The validation results satisfied the predetermined acceptance criteria. The validated method was used to quantify virus samples produced in an animal cell culture-based production system. The method was able to quantify the NDV samples from mid- or late-production phases, but not effective on samples from the early-production phase. For comparison with other quantifiable methods, immunoblotting, plaque assay, and tissue culture infectious dose 50 (TCID50) assay were also performed with the NDV samples. The results demonstrated that the real-time RT-PCR method is suitable for the rapid quantification of virus particles produced in an animal cell-culture-based production system irrespective of viral infectivity. © The Korean Society for Microbiology and Biotechnology. Source

Chae J.-W.,Chungnam National University | Seo J.-W.,New Drug Research Team | Mahat B.,Chungnam National University | Yun H.-Y.,Uppsala University | And 4 more authors.
Drug Development and Industrial Pharmacy | Year: 2014

The study of pharmacokinetics of alendronate has been hampered by difficulties in accurately and reproducibly determining their concentrations in serum and urine. Thus, pharmacokinetic characteristics of alendronate have been described in many reports based on urinary excretion data; and plasma pharmacokinetics and the simultaneous pharmacokinetic models of alendronate in plasma and urine are not available. The aims of this study were to measure alendronate concentration in plasma and excretion in urine concurrently and to develop compartmental pharmacokinetic model using urine data. In open-label, single-dose pharmacokinetic study, 10 healthy male volunteers received oral dose of alendronate (70mg tablet). Blood and urine alendronate concentrations were determined using validated high-performance liquid chromatography method. Non-compartmental analysis was performed using WinNonlin program (Pharsight Inc., Apex, NC). A one-compartment pharmacokinetic model was applied to describe pharmacokinetics of alendronate. A peak plasma alendronate concentration of 33.10±14.32ng/mL was attained after 1.00±0.16h. The cumulative amount of alendronate excreted in urine and peak excretion rate were 731.28±654.57μg and 314.68±395.43μg/h, respectively. The model, which included first-order absorption rate for oral dosing, showed good fit to alendronate data obtained from plasma and urine. The absorption rate constant was 2.68±0.95h-1. The elimination rate constants Kurine and Knon-ur were 0.005±0.004h-1 and 0.42±0.08h-1, respectively. The pharmacokinetics of alendronate in plasma and urine of healthy men can be predicted using one-compartment model, and thus the behavior of drug in plasma can be estimated from urinary excretion data. © 2014 Informa Healthcare USA, Inc. Source

Jang J.,Korea University | Moon S.-J.,R and P Korea Co. | Hong S.-H.,Hanmi Research Center | Kim I.-H.,Korea University
Biotechnology Letters | Year: 2010

Most animal cell culture media can be buffered using bicarbonate and high pressure CO2 in a closed system. However, in an open system, the pH of the culture media increases continuously due to the marked difference in CO2 pressure between the culture media and the atmosphere. Therefore, it is important to measure the exact pH of the culture media in an intact closed system. In this study, a pH measurement method was developed using visible light. The pH was calculated from light absorbance by the cells and by the culture media. This method was successfully applied to both suspension and anchorage-dependent cell cultures. © 2010 Springer Science+Business Media B.V. Source

Nam H.-J.,Seoul National University | Kim H.-P.,Seoul National University | Yoon Y.-K.,Seoul National University | Hur H.-S.,Seoul National University | And 10 more authors.
Cancer Letters | Year: 2011

Trastuzumab, a HER2 directed treatment has shown clinical benefit in HER2 amplified gastric cancer. This study demonstrated the potent antitumor activity of HM781-36B, a quinazoline-based irreversible pan-HER inhibitor, in HER2 amplified gastric cancer cells (SNU216 and N87) in vitro and in vivo. HM781-36B inhibited phosphorylation of HER family and downstream signaling molecules, and induced apoptosis and G1 arrest. Furthermore, HM781-36B exerted synergistic effects with chemotherapeutic agents in both HER2 amplified and HER2 non-amplified gastric cancer cells. Therefore, HM781-36B may be useful for the treatment of HER2 amplified gastric cancer alone or in combination with chemotherapeutic agents. © 2011 Elsevier Ireland Ltd. Source

Kim H.J.,Seoul National University | Kim H.-P.,Seoul National University | Yoon Y.-K.,Seoul National University | Kim M.-S.,Hanmi Research Center | And 8 more authors.
Anti-Cancer Drugs | Year: 2012

HM781-36B is an orally administered pan-human epidermal growth factor receptor (HER) inhibitor. To explore the role of pan-HER inhibitor in breast cancer, we investigated the antitumor effect and mechanisms of HM781-36B in breast cancer cell lines. Six breast cancer cell lines (BT474, MDA-MB-453, SK-BR-3, T47D, MCF-7, and MDA-MB-231) were tested. The growth inhibitory effect was assessed using the tetrazolium bromide [3-(4,5-dimethylthiazole-2-yl)-2,5- diphenyl-tetrazolium bromide] assay. The cell cycle at various concentrations of HM781-36B was analyzed by flow cytometry, and analysis of downstream molecules was performed by western blot analysis. Interaction of HM781-36B with cytotoxic chemotherapeutic agents was analyzed by combination index using CalcuSyn. The HER2-amplified cells (SK-BR-3, BT474, and MDA-MB-453) were sensitive to HM781-36B (IC50 =0.001 μmol/l, 0.0012 μmol/l, and 0.0095 μmol/l, respectively). HM781-36B induced G1 arrest and resulted in apoptosis. It reduced the level of p-HER2, p-AKT, p-ERK, and p-STAT3. HM781-36B combined with 5-fluorouracil, cisplatin, paclitaxel, or gemcitabine showed a synergistic inhibitory effect on the HER2-amplified and on some of the HER2-nonamplified breast cancer cells. HM781-36B could be a promising treatment for HER2-amplified breast cancer as a single agent or in combination with cytotoxic agents and can be a candidate for treatment of HER2-nonamplified breast cancer in combination with cytotoxic agents. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins. Source

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