• IMMUNE NETWORK
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• v.4 no.4
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• pp.237-243
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• 2004

Background: The normal functions of the cell cycle inhibitor p16INK4a are frequently inactivated in many human cancers. Over 80% of hepatocellular carcinoma (HCC) cases lack a functional p16/Rb pathway. p16/Rb pathway, as well as p53 pathway, is considered as one of key components of tumor suppression. Methods: To study the roles of p16INK4a in HCC, a stable cell line expressing exogenous p16 was generated from SNU-449 hepatocellular carcinoma cells lacking endogenous p16, and suppression subtractive hybridization (SSH) was performed in parallel with the control cells. Results: 1) SSH identifies fibronectin (FN1), crystallin ${\alpha}B$ (CRYAB), Rac1, WASP, RhoGEF, and CCT3 as differentially-expressed genes. 2) Among the selected genes, the up-regulation of FN1 and CRYAB was confirmed by Northern blot, RT-PCR and by proteomic methods. Conclusion: These genes are likely to be associated with the induction of stress fiber and stabilization of cytoskeleton. Further studies are required to clarify the possible role of p16 in the signal transduction pathway.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.206-209
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• 2001

Recombinant human GM -CSF was expressed and secreted from transgenic rice cell suspension cultures in its biologically active form. This was accomplished by transforming rice callus tissues with an expression vector, pMYN44. containing the hGM -CSF cDNA. Regulated expression and secretion of hGM -CSF from this vector achieved using the promoter, signal peptide, and terminator from a rice alfa-amylase gene Amy3D. The Amy3D gene is expressed in response to sugar deprivation. The recombinant hGM -CSF was expressed from the transgenic rice cell culture on the sugar-free medium as a yield of about 110 mg/L in the culture filtrate, which was determined by ELISA. Biological activity of hGM-CSF was confirmed by measuring the proliferation of the hGM -CSF dependent TF -1 cells.(This work was supported by a grant from the NRL program of the Korean Ministry of Science and Technology. Shin, Y.- J.. Lee. J.-H and Kwon, T.-H. have been supported by BK21 program from the Korean Ministry of Education)

• Molecular & Cellular Toxicology
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• v.3 no.4
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• pp.231-237
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• 2007

Exposure to DNA-damaging agents can elicit a variety of stress-related responses that may alter the expression of genes associated with numerous biological pathways. We used 19 k whole human genome chip to detect gene expression profiles and potential signature genes in human normal hepatocytes (THLE-3) by treatment of five direct acting mutagens, furylfuramide (AF-2), N-nitroso-N-methylurea (MNU), methylmethanesulfonate (MMS), 4-nitroquinoline-N-oxide (4-NQO) and 2-nitrofluorene (2NF) of the $IC_{20}$ concentration for 3 h. Fifty one up-regulated common genes and 45 down-regulated common genes above 1.5-fold by five direct-acting mutagens were identified by clustering analysis. Many of these changed genes have some association with apoptosis, control of cell cycle, regulation of transcription and signal transduction. Genes related to these functions, as TP73L, E2F5, MST016, SOX5, MAFB, LIF, SII3, TFIIS, EMR1, CYTL1, CX3CR1 and RHOH are up-regulated. Down-regulated genes are ALOX15B, xs155, IFITM1, BATF, VAV2, CD79A, DCDC2, TNFSF8 and KOX8. We suggest that gene expression profiling on mutagens by toxicogenomic analysis affords promising opportunities to reveal potential new mechanistic markers of genotoxicity.

• Journal of Biomedical Engineering Research
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• v.16 no.2
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• pp.239-248
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• 1995

The method of increasing signal to noise ratio (SNR) in a Hadamard transform spectrometer (HTS) is multiplexing. The multiplexing is executed by a mask. Conventional masks are mechanical or electro-optical. A mechanical mask has disadvantages of jamming and misalignment. A stationary electro-optical mask has a disadvantage of information losses caused by spacers which partition mask elements. In this paper, a mixed-concept electro-optical mask (MCEOM) is developed by expanding the length of a spacer to that of lon-off mask element. An MCEOM is operated by stepping a movable mask. 2N measurements are required for N spectrum estimates. The average mean square error (AMSE) using MCEQM is equal to that using a stationary electro-optical mask without spacers for large N. The cost of manufacturing an MCEOM is lower than that of producing a conventional electro-optical mask because an MCEOM needs only (N + 1)/2 on-off mask elements whereas the con¬ventional electro-optical mask needs N on-off mask elements. There are no information losses in the spectrometers having an MCEOM.

• Journal of Biomedical Engineering Research
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• v.16 no.2
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• pp.175-182
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• 1995

Despite the simplicity of processing, a conventional autocorrelation function (ACF) method for the precise determination of fetal heart rate (FHR) has many problems. In case of weak or noise corrupted Doppler ultrasound signal, the ACF method is very sensitive to the threshold level and data window length. It is very troublesome to extract FHR when there is a data loss. To overcome these problems, the high resolution pitch detection algorithm was adopted to estimate the FHR. This method is more accurate, robust and reliable than the ACF method. With a lot of calculation, however, it is impossible to process real time FHR estimation. This paper is presented a new FHR estimation algorithm for real time processing and studied the real time FHR monitoring system by high resolution pitch detection algorithm.

• Journal of Biomedical Engineering Research
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• v.25 no.3
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• pp.227-233
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• 2004

In this paper, it is proposed that the four channel electrode arrangement at a frontal lobe and the noise reduction method using a JADE for the EEG biofeedback system. The proposed electrode arrangement is based on the retina-cornea dipole model. Using JADE and signals which are acquired by the proposed arrangement, four independent components are separated. To estimate a pure EEG component among four components, it is measured that a ratio of alpha wave to the whole signal and then the component that has a maximum value is considered as a pure EEG which the noise is eliminated. As a result of experiments, the proposed methods are effective in reduction of noises during acquisition of the EEG.

• BMB Reports
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• v.43 no.8
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• pp.541-546
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• 2010

We utilized a mammalian expression system to purify and characterize autotaxin (ATX)/lysophospholipase D, an enzyme present in the blood responsible for biosynthesis of lysophosphatidic acid. The human ATX cDNA encoding amino acids 29-915 was cloned downstream of a secretion signal of CD5. At the carboxyl terminus was a thrombin cleavage site followed by the constant domain (Fc) of IgG to facilitate protein purification. The ATX-Fc fusion protein was expressed in HEK293 cells and isolated from conditioned medium of a stable clone by affinity chromatography with Protein A sepharose followed by cleavage with thrombin. The untagged ATX protein was further purified to essential homogeneity by gel filtration chromatography with a yield of approximately 5 mg/liter medium. The purified ATX protein was enzymatically active and biologically functional, offering a useful tool for further biological and structural studies of this important enzyme.

• BMB Reports
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• v.51 no.11
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• pp.596-601
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• 2018

Colon cancer is one of the most lethal and common malignancies worldwide. STK899704, a novel synthetic agent, has been reported to exhibit anticancer effects towards numerous cancer cells. However, the effect of STK899704 on the biological properties of colon cancer, including cancer cell migration and cancer stem cells (CSCs), remains unknown. Here, we examined the inhibitory effect of STK899704 on cell migration and CSC stemness. In the wound healing assay, STK899704 significantly inhibited the motility of colon cancer cells. Furthermore, STK899704 downregulated the mRNA expression levels of the cell migration mediator focal adhesion kinase (FAK). STK899704 also suppressed mitogen-activated protein kinase kinase and extracellular signal-regulated kinase, which are downstream signaling molecules of FAK. Additionally, STK899704 inhibited stemness gene expression and sphere formation in colon cancer stem cells. These results suggest that STK899704 can be used to treat human colon cancer.

• Toxicological Research
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• v.29 no.3
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• pp.211-215
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• 2013

The trace toxic metal copper was assayed using mercury immobilized on a carbon nanotube electrode (MCW), with a graphite counter and a reference electrode. In this study, a macro-scale convection motor was interfaced with a MCW three-electrode system, in which a handmade MCW was optimized using cyclic- and square-wave stripping voltammetry. An analytical electrolyte for tap water was used instead of an expensive acid or base ionic solution. Under these conditions, optimum parameters were 0.09 V amplitude, 40 Hz frequency, 0.01 V incremental potential, and a 60-s accumulation time. A diagnostic working curve was obtained from 50.0 to 350 ${\mu}g/L$. At a constant Cu(II) concentration of 10.0 ${\mu}g/L$, the statistical relative standard deviation was 1.78% (RSD, n = 15), the analytical accumulation time was only 60 s, and the analytical detection limit approached 4.6 ${\mu}g/L$ (signal/noise = 3). The results were applied to non-treated drinking water. The content of the analyzed copper using 9.0 and 4.0 ${\mu}g/L$ standards were 8.68 ${\mu}g/L$ and 3.96 ${\mu}g/L$; statistical values $R^2$ = 0.9987 and $R^2$ = 0.9534, respectively. This method is applicable to biological diagnostics or food surveys.

• Molecular & Cellular Toxicology
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• v.1 no.1
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• pp.32-39
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• 2005

Polycyclic aromatic hydrocarbons (PAHs) are an important class of environmentally prevalent xenobiotics that exert complex effects on the biological system and characterized as probably carcinogenic materials. Single cell gel electrophoresis assays were performed in order to evaluate DNA damage occurring in the T-and B lymphocytes, spleens (T/B-cell), bone marrow, and livers of mouse exposed to mixture of PAHs (Benzo(a)pyrene, Benzo(e)pyrene, Fluoranthene, Pyrene) at dose of 400, 800, or 1600 mg/kg body weight for 2 days. DNA damage of the cells purified from mice was increased in dose dependent manner. In the blood cells and organs, DNA damage was also discovered to vary directly with PAHs. Especially T-cells had been damaged more than B-cell. Plasma proteomes were separated by 2-dimensional electrophoresis with pH 4-7 ranges of IPG Dry strips and many proteins showed significant up-and -down expressions with the dose dependent manner. Of these, significant 4 spots were identified using matrix-assisted laser desorption/ionization-time of fight (MALDI-TOF) mass spectrometry. Identified proteins were related to energy metabolism and signal transduction.