• The Korean Journal of Pain
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• v.23 no.4
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• pp.236-241
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• 2010

Background: Selective inhibitors of cycloosygenase (COX)-2 are commonly used analgesics in various pain conditions. Although their actions are largely thought to be mediated by the blockade of prostaglandin (PG) biosynthesis, evidences suggesting endogenous opioid peptide link in spinal antinociception of COX inhibitor have been reported. We investigated the roles of opioid receptor subtypes in the spinal antionociception of selective COX-2 inhibitor. Methods: To examine the antionociception of a selective COX-2 inhibitor, DUP-697 was delivered through an intrathecal catheter, 10 minutes before the formalin test in male Sprague-Dawley rats. Then, the effect of intrathecal pretreatment with CTOP, naltrindole and GNTI, which are ${\mu}$, $\delta$, and k opioid receptor antagonist, respectively, on the analgesia induced by DUP-697 was assessed. Results: Intrathecal DUP-697 reduced the flinching response evoked by formalin injection during phase 1 and 2 Naltrindole and GNTI attenuated the antinociceptive effect of intrathecal DUP-697 during both phases of the formalin test, CTOP reversed the antinociception of DUP-697 during phase 2, but not during phase 1, Conclusions: Intrathecal DUP-697, a selective COX-2 inhibitor, effectively relieved inflammatory pain in rats. The $\delta$ and $\kappa$ opioid receptors are involved in the activity of COX-2 inhibitor on the facilitated state as well as acute pain at the spinal level, whereas the ${\mu}$ opioid receptor is related only to facilitated pain.

• Molecules and Cells
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• v.38 no.5
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• pp.457-465
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• 2015

The 15-kDa selenoprotein (Sep15) is a selenoprotein residing in the lumen of the endoplasmic reticulum (ER) and implicated in quality control of protein folding. Herein, we established an inducible RNAi cell line that targets Sep15 mRNA in Chang liver cells. RNAi-induced Sep15 deficiency led to inhibition of cell proliferation, whereas cell growth was resumed after removal of the knockdown inducer. Sep15-deficient cells were arrested at the G1 phase by upregulating p21 and p27, and these cells were also characterized by ER stress. In addition, Sep15 deficiency led to the relocation of focal adhesions to the periphery of the cell basement and to the decrease of the migratory and invasive ability. All these changes were reversible depending on Sep15 status. Rescuing the knockdown state by expressing a silent mutant Sep15 mRNA that is resistant to siRNA also reversed the phenotypic changes. Our results suggest that SEP15 plays important roles in the regulation of the G1 phase during the cell cycle as well as in cell motility in Chang liver cells, and that this selenoprotein offers a novel functional link between the cell cycle and cell motility.

• Journal of the Korean Chemical Society
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• v.36 no.1
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• pp.57-65
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• 1992

The method for investigating the retention behavior and separation optimization was studied to develop a reversed-phase liquid chromatography of eleven thiocarbamates that are used as herbicides. As an isocratic elution system, the statistical simplex technique was applied to find the optimum separation conditions. The resolution was quantitatively evaluated by using COF and ORM method. For thiocarbamate herbicides in which the elution order varies dramatically with solvent composition, the ORM method gave better result than the COF method. For the solvent composition of mobile phase in the ORM method, the ratio of methanol : acetonitrile : tetrahydrofuran : water was 16 : 29 : 2 : 53. Also in this research, an adjusted COF $(\overline{COF})$ method was proposed to rectify the defect in the current COF method, and the compositional ratio of mobile phase containing methanol : acetonitrile : water was 29.5 : 21.5 : 49.0 result of which is similar to that obtained by the ORM method.

• Bulletin of the Korean Chemical Society
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• v.28 no.5
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• pp.737-744
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• 2007

An isotope dilution-liquid chromatography/tandem mass spectrometric method was developed as a candidate reference method for the accurate determination of acrylamide in potato chips, starch-rich foodstuff cooked at high temperature. Sample was spiked with 13C3-acrylamide and then extracted with water. The extract was further cleaned up with an Oasis HLB solid-phase extraction (SPE) cartridge and an Oasis mixed-phase cation exchange (MCX) SPE cartridge. The extract was analyzed by using LC/ESI/Tandem MS in positive ion mode. LC with a medium reversed-phase (C4) column was optimized to obtain adequate chromatographic retention and separation of acrylamide. MS was operated to selectively monitor [M+H]+ ions of the analyte and its isotope analogue at m/z 72 and m/z 75, respectively. Sample was also analyzed by the LC/MS with selectively monitoring the collisionally induced dissociation channels of m/z 72 → m/z 55 and m/z 75 → 58. Compared to the LC/MS chromatograms, the LC/MS/MS chromatograms showed substantially reduced background chemical noises coming from solvent clusters formed during ESI spray processes and interferences from sample matrix. Repeatability and reproducibility studies showed that the LC/MS/MS method is a reliable and reproducible method which can provide a typical method precision of 1.0% while the LC/MS results are influenced by chemical interferences.

• Journal of the Korean Chemical Society
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• v.8 no.2
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• pp.47-56
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• 1964

When a developed paper partition chromatogram was irradiated by means of the pneumatic tube system of the Korean research reactor (neutron flux: 1.5 ${\times}10^{12}n/cm^2$sec.) the qualitative confirmation of the developed spot on the chromatogram was possible. In the case of an organic halogen compounds (chloro-acid, chloro-ester, iodide, and fluoride) the spot analysis was possible by the present method whereas the same spot could not give the distinct coloring with a common coloring reagents. Filterpaper thickness calibration and activity calibration induced by irradiation of the components of the filter paper, which were a source of erraneous interpretation of the spot, were searched and an average filterpaper calibration method and filter paper activity were improvised to obtain a good qualitative analysis of the spot. Finally the use and applicability of this method for the analysis identification of an organic halogen compound were evaluated. As the filter paper phase an ordinary phase (Whatmann #1, filter paper) and reversed phase (liquid paraffin impregnated) were used.

• FOCUS: LIFE SCIENCE
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• no.1
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• pp.1.1-1.4
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• 2024

This article provides comprehensive guidance on the maintenance, cleaning, regeneration, and storage of silica-based HPLC (High-Performance Liquid Chromatography) columns. The general considerations emphasize the importance of using in-line filters and guard cartridges to protect columns from blockage and irreversible sample adsorption. While these measures help, contamination by strongly adsorbed sample components can still occur over time, leading to an increase in back pressure, loss of efficiency, and other issues. To maximize column lifetime, especially with UHPLC (Ultra-High Performance Liquid Chromatography) columns, it is advisable to use ultra-pure solvents, freshly prepared aqueous mobile phases, and to filter all samples, standards, and mobile phases. Additionally, an in-line filter system and sample clean-up on dirty samples are recommended. However, in cases of irreversible compound adsorption or column voiding, regeneration may not be possible. The document also provides specific recommendations for column cleaning procedures, including the flushing procedures for various types of columns such as reversed phase, unbonded silica, bonded normal phase, anion exchange, cation exchange, and size exclusion columns for proteins. The flushing procedures involve using specific solvents in a series to clean and regenerate the columns. It is emphasized that the flow rate during flushing should not exceed the specified limit for the particular column, and the last solvent used should be compatible with the mobile phase. Furthermore, the article outlines the storage conditions for silica based HPLC columns, highlighting the impact of storage conditions on the column's lifetime. It is recommended to flush all buffers, salts, and ion-pairing reagents from the column before storage. The storage solvent should ideally match the one used in the initial column test chromatogram provided by the manufacturer, and column end plugs should be fitted to prevent solvent evaporation and drying out of the packing bed.

• Microbiology and Biotechnology Letters
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• v.16 no.3
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• pp.250-258
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• 1988

Lipases are well known as the enzymes which catalyze the hydrolysis of ester bonds combining aliphatic chains and glycerol on mono-, di- and triglycerides. Their reactions are characterized by be-ing heterogeneous and catalyzing the water-insoluble substrates. This property has been one of the Hurdles which delayed the application of lipases in fats and oils industry, However, with the development of biological reaction system of which organic solvent is introduced in part or whole as the reaction media, enzymatic manipulation of fats and oils is attracting increasing attention from the academic and industrial sectors. Trials in two-phase system and reversed micellar system to produce fatty acids through enzymatic hydrolysis of triglycerides preyed to be efficient in respect to volumetric productivity, fat hydrolysis rate, product separation, etc. In organic solvent system lipases have been found to have the ability to catalyze aminolysis, transesterification, esterification, thiotransesterification and oximolysis that are virtually impossible to catalyze in water. The organic solvent system is being extensively used in interesterifying glycerides to produce a fat with the modified physical and chemical nature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1156-1164
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• 2010

Structured lipids (SLs) were synthesized by enzymatic interesterification with evening primrose oil (EPO) and rice bran oil (RBO) in a batch-type reactor. The interesterification was performed using a water shaker for 24 hr at $55^{\circ}C$. Mixing speed was set at 200 rpm and Lipozyme RM IM (immobilized lipase from Rhizomucor miehei, 10% by weight of total substrates) was used as a biocatalyst. Rice bran oil and evening primrose oil were interesterified with various molar ratios (RBO : EPO, 1:3, 1:4, and 1:5 mol/mol). Reversed-phase high performance liquid chromatography connected with evaporative light-scattering detector was performed to separate the triacylglycerol (TAG) species of SLs. In the fatty acid analysis, $\gamma$-linolenic acid (7.9 mol%), linoleic acid (67.3 mol%) and oleic acid (13.2 mol%) were the most abundant fatty acids in the SLs. During 24 hr reaction, most of the reaction occurred within 3 hr. TAG compositions, tocopherols and phytosterols were also analyzed. In the TAG species analysis, LLL (ECN=42, L=linoleic acid) dramatically decreased when the reaction time increased.

• Journal of the Korean Chemical Society
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• v.33 no.3
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• pp.287-294
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• 1989

The optimum condition for the separation of priority pollutant phenols using isocratic elution has been determined. The elution behavior of eleven phenols has been also studied to interpret the retention. The reversed phase liquid chromatographic methods were performed on a ${\mu}$-Bondapak $C_{18}$ column with methanol-water, acetonitrile-water, and THF water mixtures as mobile phases. The COF method, where Snyder's solvent triangle concept was combined with a mixture-design statistical technique, was used to optimize the strength and selectivity of solvents for the separation of phenols. The optimum solvent composition, which gives a complete separation of eleven phenols, was found to be $MeOH:ACN:H_2O$ = 7:40:53. The plots of ln k' vs. -${\Delta}H^{\circ}$ and ${\Sigma}{\pi}$ of phenols showed relatively good linearities. Effect of van der Waals volume, pi-energy and hydrogen bonding on the retention of phenols were investigated. The following equation with the correlation coefficient of 0.9927 for ACN-water solvent system was obtained; $log^{k'}=2.515{\times}10^{-2}VWV-1.301{\times}10^{-1}E-3.674{\times}10^{-1}$

• Journal of the Korean Chemical Society
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• v.31 no.1
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• pp.55-63
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• 1987

The systematic investigation of the retention behaviors of 18 monosubstituted benzenes in reversed-phase liquid chromatography(RPLC) was studied in order to predict the separation possibility of their mixtures and study the contribution of substituent group to the retentions of solutes. The columns and mobile phases employed in this study were $\mu$ -Bondapak $C_{18}$, $\mu$-Bondapak phenyl columns and methanol/water, acetonitrile/water, and THF/water, respectively. The polar substituents such as phenol, aniline, acetophenone and benzonitrile have smaller capacity factor(k') values than benzene, while nonpolar ones such as alkylbenzenes and halobenzenes show larger k' value. The capacity factors of all solutes increased on both C18 bonded and phenyl bonded phases as the organic solvent content of three organic solvent-water mixtures decreased. The absolute differences in capacity factor(${\Delta}k$') between substituent and benzene were graphically shown for the prediction of the separation of the mixture and interpretation of the elution behavior of substituent. In addition, the selectivity of solvent system for the separation of the mixture was investigated in both two columns and three mobile phases.