• Analytical Science and Technology
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• v.12 no.4
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• pp.326-331
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• 1999

The metabolites of 1,2,4-trimethylbenzene (TMB) were synthesized and determined by capillary electrophoresis (CE). The optimum conditions of CE for the separation and determination of 3,4-, 2,4-, 2,5-dimethylbenzoic acid and 3,4-, 2,4-, 2,5-dimethylhippuric acid from the rat urine were as following: the fused silica capillary($75{\mu}m$ i.d. ${\times}$ 36 cm length, 29 cm to detector) was used and kept at $15^{\circ}C$. The applied voltage was 10㎸ and compounds were detected at UV 210 mnm and 254 nm. The running electrolyte was 0.1 M phosphate buffer (pH 7) containing 15 mM of ${\beta}-CD$ and 3% of 2-propanol. The relative amount of the metabolite of 1,2,4-TMB in the rat urine was 56.7% of 3,4-isomer, 30.5% of 2,4-isomer and 12.8% of 2,5-isomer. This method can be applied to the analysis of TMB-metabolites in human urine.

• Journal of Environmental Health Sciences
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• v.35 no.3
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• pp.153-161
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• 2009

The purpose of this paper is to evaluate 1) blood lead levels of workers at auto repair shops as Biological Exposure Indices (BEI) of toxic substances such as lead and toluene that are produced during automotive painting process, 2) the differences depending on personal characteristics of workers who have been exposed to toluene by using urine hippuric acid concentration as a marker and 3) the correlation between the concentration of hazardous chemicals in each workplace and the BEL. All subjects were male with a mean age of 36.2 years. In terms of age, most were in the 30 to 40 age group (13 persons, 48.1%). In relation to the length of work experience, the highest proportion had experience of 10 years of less (18 persons, 66.7%). Twenty three workers were cigarette smokers (85.2%) while 4 (14.8%) were non-smokers. In addition, more than 80% of the workers drank alcohol. Dust concentration and toluene exposure during automotive painting showed no significant difference with age, length of work experience, smoking and drinking while a significant difference (p<0.05) has been detected between lead concentration and smoking. The geometric mean of dust concentration, lead concentration and toluene concentration were $0.38mg/m^3,\;0.0021mg/m^3$ and 1.08ppm respectively. In addition, the geometric mean of blood lead levels and urine hippuric acid concentration were $1.70{\mu}g/dl$ and 0.25g/g respectively, which were lower than the standard levels suggested by the Ministry of Labor. To determine the influential factors on blood lead and urine hippuric acid concentrations, a correlation analysis has been conducted with variables of air, lead and toluene concentrations, age, length of work experience and amount of cigarette smoking. According to the analysis, a relatively high correlation (p<0.01) has been observed between air lead concentration and biological sample concentration.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.22 no.1
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• pp.28-36
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• 2022

Purpose: Detection of abnormal metabolites in plasma amino acid (PAA) and urine organic acid (UOA) analyses has been used to diagnose clinical mitochondrial diseases, such as Leigh syndrome. In this study, the diagnostic values and effectiveness of PAA and UOA analyses were reviewed. Methods: This was a retrospective study of patients with Leigh syndrome who were diagnosed between 2003 and 2018 in a single tertiary care center. Through a whole mitochondrial sequencing and nuclear DNA associated mitochondrial gene panel analysis, 19 patients were found to be positive for mitochondrial DNA (mtDNA) mutation-associated Leigh syndrome, and 57 patients were negative. Their PAA and UOA analyses results were then compared. Results: In the comparison of the PAA and UOA analyses results between the two groups, no abnormal metabolites showed obvious differences between the mtDNA mutation-positive Leigh syndrome and mtDNA mutation-negative Leigh syndrome groups. Conclusion: PAA and UOA analyses are inappropriate test methods for diagnosing Leigh syndrome or screening of mtDNA mutation-associated Leigh syndrome. However, UOA analysis might still be a suitable screening test for Leigh syndrome.

• Analytical Science and Technology
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• v.21 no.5
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• pp.412-423
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• 2008

A procedure based on solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry has been developed for the simultaneous analysis of 55 basic drugs in equine urine. The test scope covers diversified classes of drugs including some ${\beta}$-blockers, ${\beta}$-agonists, antihypotensives, CNS stimulants, sedatives, tranquilizers, antidepressants, antihypertensives and so on. LC-MS/MS separation and quantification was carried out in positive electrospray ionization and multiple reaction monitoring (MRM) mode. Four different brands of mixed mode cation exchange SPE sorbents; UCT XTRACT$^{(R)}$ XRDAH, Supelco DSC-MCAX$^{(R)}$, Varian Bond Elut Certify$^{(R)}$ and Waters Oasis$^{(R)}$ MCX were compared. The UCT XTRACT$^{(R)}$ XRDAH sorbent provided the best results in the preconcentration of samples, yielding relative recoveries higher than 80% except for terbutaline (41.3%), salbutamol (71.5%), heptaminol (70.7%), phenylpropanolamine (66.3%). Detection limits of the target drugs provided by the proposed analytical procedure were between 0.2~8.3 ng/mL.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.31 no.1
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• pp.41-45
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• 2020

Objective: The objective of this study was to assess serum, hair, and urinary magnesium (Mg) levels in children with attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and both ASD and ADHD to reveal potential interactive effects. Methods: A total of 148 boys aged 4-9 years old were enrolled in this study, including 44 children with ADHD, 40 pediatric patients with ASD, 32 patients with both ADHD and ASD, as well as 32 healthy neurotypical children. Hair, serum, and urinary Mg levels were assessed using inductively-coupled plasma mass spectrometry (ICP-MS). Laboratory quality control was performed using certified reference materials of human hair, plasma, and urine. Results: No significant group difference in serum Mg levels was observed. Mg content in hair was found to be reduced in children with ADHD and ADHD+ASD compared to that in healthy controls by 11% and 15%, respectively. Urinary Mg levels in children with ADHD+ASD exceeded the control, ADHD, and ASD values by 51, 76, and 65%, respectively. Factorial analysis revealed significant contribution of ADHD to hair and urinary Mg levels. Multiple regression analysis demonstrated that hair and urinary Mg levels were considered as significant predictors of neurodevelopmental disorder complexity. Conclusion: We propose that impaired Mg status may provide a link between ADHD and ASD.

• Journal of Preventive Medicine and Public Health
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• v.44 no.1
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• pp.41-47
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• 2011

Objectives: This study assessed the factors that have an influence on the residents exposed to heavy metals, and we utilized the findings to establish the proper management of abandoned metal mines in the future. Methods: For a total of 258 residents who lived close to abandoned mines in Gangwon-province and Gyeonggi-province, the exposure factors and biomarkers in their blood and urine were comparatively analyzed via multiple regression analysis. Results: The blood levels of lead and mercury and the cadmium levels in urine were found to be higher in the study group than that in the average Korean. For the blood levels of heavy metals according to each exposure factor, all of them were found to be significantly higher in both of the group residing for a longer period of time and the group living closer to the source of pollutants. Multiple regression analysis disclosed that all the heavy metals, except lead, in their blood were significantly reduced in proportion to the increased distance of inhabitancy from the mines. Their other biomarkers were within the normal ranges. Conclusions: We found that the distance between the residential village and the mines was a factor that affects the blood level of heavy metals in the villagers. This finding could be an important factor when developing a management model for the areas that surround abandoned metal mines. (ED note: I much like this important study.)

• Analytical Science and Technology
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• v.7 no.3
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• pp.413-419
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• 1994

The determination of the neuromuscular blocking agents vecuronium bromide(VeBr) in biological fluids has been investigated. The method depends on the formation of insoluble red complex between vecuronium bromide and rose bengal in aqueous layer. The amount of vecuronium bromide was calculated from that of extracted rose bengal which was determined by spectrofluorimetry or HPLC/fluorescence detection method. It was possible to analyze VeBr in the range of $2{\sim}32{\mu}g/ml$(r=0.998 for water soln., 0.999 for urine, 0.996 for plasma). This method was applied to the analysis of VeBr in biological fluids, urine and plasma.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9785-9790
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• 2014

Background: The aim of this study is to examine the association of urinary cesium with breast cancer risk. Materials and Methods: We collected survey data and urine specimens from 240 women with incident invasive breast cancer before their treatment and 246 age-matched female controls between October 2009 and July 2010. Urinary concentrations of cesium were determined by inductively coupled plasma mass spectrometry. Interviews were conducted by face-to-face to obtain information on potential breast cancer risk factors. Logistic regression analysis was used to estimate the associations. Results: Creatinine-adjusted levels [median ($25^{th}$, $75^{th}$) ug/g] of cesium in cases and controls were 17.6 (13.1, 24.0) and 19.3 (15.3, 25.7), respectively. After adjustment for potential risk factors, women in the second and highest tertile of cesium showed a decreased risk of breast cancer in a dose-dependent manner as compared with those in the lowest tertile [ORs and 95% CIs: 0.75 (0.46-1.22) and 0.50 (0.30-0.82), respectively]. This decrease was more evident in women with ER positive or localized clinical stage in an exploratory stratification analysis. Conclusions: These findings suggest that cesium may have anticancer efficacy and urinary cesium has potential as a biomarker for breast cancer risk assessment.

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.659-666
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• 1991

A systematic analysis of 18 stimulants and narcotic analgesics containing nitrogen atom (s) in human urine by gas chromatography with nitrogen phosphorus detector (GC-NPD), is described. The urinary extract with diethyl ether at pH 8.5 showed good recoveries of the drugs and less interference peaks on GC chromatogram. Retention data were standardized by the calculation of relative retention times using diphenylamine as the internal standard. The relative standard deviations of retention times were less than 0.1% for the within-run analyses. The response factor (RRF) of a drug relative to the internal standard was calculated. RRF decreased with increasing number of nitrogen atoms. This technique can be adapted to various analytical toxicology problems.

• 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.