• Analytical Science and Technology
• /
• v.22 no.5
• /
• pp.407-414
• /
• 2009

A simultaneous determination method for cholesterol, lanosterol and desmosterol was developed using gas chromatography/mass spectrometry. Urine was enzymatically hydrolyzed with ${\beta}$-glucuronidase/arylsulfatase. Samples were prepared using extractions with a mixture of ethyl acetate-hexane (2:3, v/v), followed by derivatization with a mixture of MSTFA/TMSI/TMCS (100:2:5 v/v/v). All analyses were performed using GC/MS in selective ion monitoring mode. Good linearities ($r^2=0.998{\sim}0.999$) in calibration curve and a satisfactory recovery (80.0%~113%) were achieved. Accuracy and precision values within ${\pm}15%$ in the concentration range of 5 to 200 ng/mL were also observed for all compounds. The developed method was applied to pravastatin-treated (70 and 250 mg/kg/day for 7 days, oral) hyperlipidemia rats. Those sterols were significantly lower in drug-treated rats compared to the controls, which justifies the drug efficacy. Therefore, these results indicate that the developed method was successfully applied to examine statin drug efficacy with urine sample.

• Analytical Science and Technology
• /
• v.22 no.5
• /
• pp.386-394
• /
• 2009

Formaldehyde is used in lether manufacture, a dry plate and an explosive. It is by-product of ozonizing process in filtration plant. The effects of exposure are eye pruritus, tickle, runing nose, blocking nasal passages and headache. It also makes a dried throat and causes inflammation. It is classified as B1 group for inhalation by US. EPA, which can cause cancer in human. For analysis of formaldehyde, formaldehydes-DNPH derivative was extracted with solid cartridge and was analyzed by High Performance Liquid Chromatography/Diode Array Detector (HPLC/DAD). The detection limit was $3{\mu}g/L$ and the recoveries were 72.3~109.1% (RSD 2.9~11.5%). Water samples were collected in four Korean rivers, four times per year seasonally for 10 years from 1998 to 2007. The monitoring results were 48.8% (630/1291), $5.15{\sim}101.9{\mu}g/L$ in purified water. Because of non-carcinogen in drinking water, hazard index is calculated with RfD. Results of excess cnacer risk was below 1 and was considered as safe value.

• Proceedings of the Korea Environmental Mutagen Society Conference
• /
• 2002.11a
• /
• pp.170-170
• /
• 2002

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.86-87
• /
• 2002

Recent technological innovations in the drug discovery process such as combinatorial synthesis and high throughput screening have led to the identification of an increasingly large number of compounds at the hits-to-leads stage. Therefore, rapid and precise pharmacokinetic/metabolic screening is essential to enhance the tractability of selected leads and to minimize the risk of failure in the later stages of drug development. (omitted)

• Proceedings of the Korean Society of Applied Entomolohy Conference
• /
• 2002.05a
• /
• pp.76-76
• /
• 2002

• Bulletin of the Korean Chemical Society
• /
• v.35 no.8
• /
• pp.2585-2588
• /
• 2014

• Proceedings of the Microbiological Society of Korea Conference
• /
• 2002.10a
• /
• pp.151-158
• /
• 2002

• Proceedings of the Microbiological Society of Korea Conference
• /
• 2006.05a
• /
• pp.76-79
• /
• 2006

At present, hundreds of microbial genomes have been sequenced, and hundreds more are currently in the sequencing pipeline. As the amount of genome data is expanding, researchers are much in need of tools that can process huge amount of sequence data. Here, we will discuss about several bioinformatics tools and their applications.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.407.1-407.1
• /
• 2002

To develop immunostrip of DDT (4.4'-dichlorodiphenyl-2.2,2-trichloroethane) and its metabolites, DDT derivatives (DDA-. DDHP-. DDCP-. DDHH-. and DDHHAP-) were conjugated to carrier proteins (OVA and BSA) and three DDT derivatives (DDA. DDHP. DDCP) were conjugated to KLH for the use of coating ligand and immunogen. respectively. To screen the immunoreactivity of antibody to DDT derivatives, the coating ligand was evaluated by a competitive ELISA and DDHP-OVA was selected. (omitted)

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.214.1-214.1
• /
• 2003

Metabonomic analysis using Liquid Chromatography-Mass Spectrometry (LC-MS) was employed to test the feasibility to predict chemical-induced toxicity. Time-dependent metabolic variations were evaluated in rats treated with the model hepatotoxin, ${\alpha}$- naphthylisothiocyanate (ANIT). Urine samples of ANIT treated group and control group were collected up to 7 days postdose. Urine samples were analyzed by gradient HPLC combined with electrospray mass spectrometry. The chromatographic results were data-reduced and analyzed using principal component analysis to show the time dependent biochemical variations induced by ANIT toxicity. (omitted)