• Analytical Science and Technology
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• v.19 no.5
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• pp.433-440
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• 2006

A HPLC/UV method was developed and validated for the rapid and simultaneous determination of urinary metabolites of organic solvents, mandelic acid, hippuric acid, phenylglyoxylic acid, ortho-, meta- and para-methylhippuric acid, using a monolithic column. The mobile phase was composed of tetrabutylammonium bromide as ion-pairing reagent with a flow rate of 2.4 mL/min. The total run time was less than 2.5 min for all six analytes. Good linearities were obtained for all the metabolites with correlation coefficients above 0.9993. Intra-day precision, accuracy and inter-day precision was 0.01~7.32%, 83.9~116.3% and 0.01~7.16%, respectively. The method was validated and confirmed by quantification of the quality assurance samples of Industrial Safety and Health Research Institute, Korea Occupational Safety and Health Agency.

• Journal of Environmental Health Sciences
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• v.50 no.1
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• pp.25-35
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• 2024

Background: There are concerns about the health effects of various environmental pollution exposures among residents living near coal-fired power plants (CFPP). Objectives: This study attempted to compare the concentrations of heavy metals in blood and urine and those of urinary volatile organic compound (VOC) metabolites according to the residential separation distance. Methods: Participants in the study totaled 334 people who have lived for more than 10 years in areas within 10 km of a CFPP. The separation distance was analyzed in quartiles by dividing it into Q1 (88 people), Q2 (89 people), Q3 (89 people), and Q4 (68 people). We explained the purpose of this study to the participants and collected blood and urine after obtaining signatures on a participation agreement. Results: The study participants were 102 males (30.5%) and 232 females (69.5%), with an average age of 71. The average length of residence and distance were 43.8 years and 4,800 meters. The geometric mean concentrations of Pb, Cd, and Hg in blood and As and Cd in urine were respective 1.35 ㎍/dL, 1.43 ㎍/L, 3.16 ㎍/L. They were 167.88 ㎍/g for creatinine and 1.58 ㎍/g creatinine. The metabolite concentrations of VOCs were 50.67 ㎍/g creatinine in t, t-muconic acid (t, t-MA), 10.73 ㎍/g creatinine in benzyl mercapturic acid, 317.05 ㎍/g creatinine in phenylglyoxylic acid, 123.55 ㎍/g creatinine in methylhippuric acid, and 190.82 ㎍/g creatinine in mandelic acid. The concentration of Pb in the blood and Cd and t, t-MA in the urine of residents within affected area of the CFPP showed statistically significant differences among distance groups. Conclusions: The concentration of urinary VOCs metabolites, especially t, t-MA, differed according to the distance groups of residents within the affected area of CFPP (p<0.05).

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.784-788
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• 2001

Reliable data on the exposure of capsaicin, which evokes hot sensation in hot red pepper, are important prerequisites for studying biological functions of capsaicin in human body since its roles are controversial according to animal and epidemiological studies. To get accurate data, the use of urinary biomarkers was considered as a measure of internal exposure of capsaicin. After 2-day-capsaicin depletion five to six women in their 20's were instructed to eat 60 or 80 g/day hot red pepper soybean paste as a capsaicin source with meal which did not contain capsaicinoid, and to collect their urine separately. HPLC conditions were set to detect capsaicinoid and urinary metabolites at the same time. Most of capsaicinoid were excreted in the form of 4-hydroxy-3-methoxybenzoic acid in three subjects at the highest dose. This result suggests the oxidation of the 4-hydroxy3-methoxybenzaldehyde, the hydrolysis product of capsaicin, is the major metabolic pathway in the human body, whereas the reduction of the aldehyde is the major route in rats. However, neither any metabolite nor the parent compound was ever shown in two of the subjects reflecting large individual differences of capsaicin absorption and/or biotransformation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.1
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• pp.49-54
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• 2011

In order to develop the methods for exposure assessment and find susceptibility markers for the workers who are exposed to low doses of toluene, xylene and other chemical in petroleum industries, we investigated the application of P-450 expression in human lymphocytes utilizing mouse monoclonal anti-rat CYP2B1/2, the levels of toluene and xylene in air and their metabolite levels in urine with the levels of expressed CYP2B1/2 proteins. The general characteristics such as age, smoking and drinking habit were no significant difference between the control and exposed workers, but the working durations and working hours were significantly different. Workers in exposed group were exposed to the mean of 2.1 ppm (range, 0.00-4.54) of toluene and 0.3 ppm (rang, 0.00-1.23) of xylene. The mean concentration of urinary hippuric acid was low and less than 1/5 of the biological exposure index recommended by the Ministry of Employment and Labor Korea. Methyl hippuric acid in urine was not detected in control and exposed workers. Also, there were no significant differences in the levels of the urinary metabolites between the control and exposed group. When chemiluminescence dot blottings were carried out utilizing mouse monoclonal antibody against CYP2B1/2, the strong density dots corresponding to a mouse monoclonal antibody was observed in the human lymphocytes from the exposed workers. These results suggested that the chemiluminescence dot blot assay for CYP of lymphocytes should be valuable for identifying CYP expression as biomarkers in the workers exposed to toluene and xylene.

• The Korean Journal of Pesticide Science
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• v.20 no.4
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• pp.300-304
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• 2016

The aim of this study were to evaluate the exposure level of pyrethroid pesticide according to spraying machine type. The urinary metabolites of pyrethroid pesticide in apple farmers were analyzed to determine the exposure level of pyrethroid pesticide. The result shows that, the spraying volume was greater in SS sprayer group than in power sprayer group. But multi variate analysis which adjust spraying volume and field area, there were no difference of urinary metabolites between two sprayer machine. To make more accurate model of pesticide exposure, the factors influencing pesticide exposure should be determined and further study should be done.

• Journal of Nutrition and Health
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• v.34 no.5
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• pp.547-553
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• 2001

This study was designed to observe the change of body composition and nutrient metabolites and the excretion of minerals during complete fasting for 10 days in thirty women. Average loss of body weight was 7.98kg and body fat was gradually reduced after 9 days fasting, but the loss of lean body mass was reduced after 7 days fasting. Serum glucose level was sustained at constant level, but serum levels of blood urea nitrogen, free acid and $\beta$-hydroxybutyrate were significantly increased during fasting but decreased after re-feeding. Urinary excretions of 3-methylhistidine, total creatinine, and urea were high in the beginning of fasting but gradually decreased. Serum level of parathyroid hormone was significantly reduced by fasting but regained after re-feeding. Serum level of minerals was at the constant level throughout the experimental period. The urinary excretion of minerals(Ca, K, Mg, P) was significantly increased in the early stage of fasting and then reduced from 7 days, but the excretion of Zn was continuously increased until the late stage of fasting. These results showed that amino acid fatty acid released from the breakdown of muscle protein and body fat, respectively, were utilized for energy during fasting. Body weight and BMI were reduced because of the increased muscle protein breakdown and body water excretion during early stage of fasting, but the significant body fat loss was after 9 days fasting. Therefore, it could be suggested to fast for longer than 10 days if the reduction of body fat was planned by fasting, and recommed to exercise and ingest more vitamins and minerals to replace the excreted minerals during fasting. (Korean J Nutrition 34(5) : 547~553, 2001)

• Environmental Analysis Health and Toxicology
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• v.25 no.4
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• pp.295-306
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• 2010

Objectives : This study was undertaken to examine the metabolomic changes due to gender and diurnal variation at sampling time and to identify an appropriate time point for urine sampling in epidemiologic studies using metabolomic profiles. Methods : Urine samples were collected twice a day (morning and afternoon) from 20 healthy Korean adults after fasting for 8 hours. The metabolomic assay was investigated using $^1H$ NMR spectroscopy coupled with the principal components analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The metabolites responsible for differentiation between groups were identified through the loading plot of PLS-DA and quantified using Chenomx NMR Suite with a 600 MHz library. Results : Metabolites responsible for differentiation in gender and sampling time were creatinine, trimethyl anine oxide (TMAO), hippurate, mannitol, citrate and acetoacetate. Dimethylamine showed difference only as a factor of diurnal time. The level of creatinine was higher in men compared to women, and the levels of citrate, TMAO, hippurate, mannitol, and acetoacetate were higher in women compared to men. The levels of creatinine, TMAO, hippurate, dimethylamine and mannitol were higher in the morning rather than the afternoon while those of citrate and acetoacetate were higher in the afternoon rather than the morning. Conclusions : Since urinary metabolomic profiles varied by gender and diurnal cycle, urine sampling should be performed at the same time point for all participants in epidemiologic studies using metabolomic profiles.

• Analytical Science and Technology
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• v.8 no.2
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• pp.139-159
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• 1995

Positive ion mass spectra of some corticosteroids were obtained by using liquid chromatography-mass spectrometry(LC-MS). The base peak of each compound showed the protonated molecular ion [$MH^+$], ammonium adduct ion [${MNH_4}^+$] or [$MH^+-60$] ion according to its chemical structure and other characteristic mass ions were [$MH^+-18$], [${MNH_4}^+-18$] and so on. Several rat urinary metabolites of methylprednisolone acetate after the oral administration were detected by the thermospray LC-MS. The identified major metabolites were 20-hydroxymethylprednisolone(20-HMP), methylprednisolone(MP) and methylprednisone(11-KMP), which were supposed to be formed by deacetylation at the position of C-21, reduction at C-20, oxidation at C-11, or due to the bond cleavage between C-17 and C-20.

• Journal of Environmental Health Sciences
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• v.44 no.6
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• pp.572-580
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• 2018

Objectives: Human biomonitoring (HBM) is a measurement of the chemicals and their metabolites in human biological samples and has been successfully employed to determine the exposure levels of environmental chemicals. In this study, we analyzed seasonal variations of the blood or urinary levels of chemicals, and assessed that these differences could affect the results of association study. Methods: The Korea National Environmental Health Survey (KoNEHS) is a nationwide survey that analyzes exposure levels of environmental pollutants, 19 kinds of chemicals including heavy metals and organic chemicals, and the exposure factors in the general population. Based on KoNEHS data, we analyzed the levels of chemicals concentrations over the total survey period (2012-2014) and each season, and assessed the association of thyroid measures with phthalate metabolite and BPA. Results: Exposure levels of blood mercury and lead were lower in summer compare to winter. Bisphenol A and PAHs metabolites were higher in spring and summer, but lower in autumn. VOCs metabolites were generally lower in summer and autumn. Phthalate metabolites were higher in all other seasons than in winter. Pyrethroid metabolite, 3-PBA, was higher in summer and autumn. Regarding seasonal variation of chemical exposures, the statistical significance and size of effects between thyroid measures and phthalate and BPA were changed with season. Conclusion: Seasonal variations of chemical exposure and health outcome should be considered for interpreting biomonitoring results from a public health context.

• YAKHAK HOEJI
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• v.42 no.6
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• pp.576-582
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• 1998

Fenfluramine, an anorectic agent, is widely abused as a diet pill in Korea because it is freely marketed in China without any regulation. The optical isomers of fenfluramine hav e different phamacological actions: d-form is used as an anorectic agent, while l-form as a neuroleptic agent. To investigate the metabolism when racemic fenfluramine was administered orally, the urinary excretion of fenfluramine was studied in rats. The enantiomeric separation of fenfluramine was performed on achiral column by gas chromatography using (S)-N-(trifluoroacetyl)-l-prolyl chloride (TFP) as a derivatizing agent. After administration of 15mg/kg of racemic fenfluramine to rats, d-, l-fenfluramine and its metabolites d- and l norfenfluramine in urine were determined by chromatographic separation of TFP derivatives on DB-1 at retention time of 11.2, 11.8, 8.4 and 8.6 min respectively. Urinary recoveries of d and l-fenfluramine in rat were 0.42-5.9O% and 0.18-1.20% respectively in urine specimens collected during first 24hr. The comparison in the levels of isomers showed that d- fenfluramine were higher than l-form, while d-norfenfluramine were lower than l-form. The ratios between parent compound and metabolite revealed that d-norfenfluramine to d-fenfluramine ranged from 1.0 to 4.4, while the ratio of l-norfenfluramine to l-fenfluramine was 8.2-21.1 indicating that l-fenfluramine is metabolized faster than the d-isomer.