• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1131-1136
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• 2013

Parabens, the esters of p-hydroxybenzoic acid, have been widely used as antimicrobial preservatives in cosmetic products, drugs, and processed foods and beverages. However, some parabens have been shown to have weak estrogenic effects through in vivo and in vitro studies. Because such widespread use has raised concerns about the potential human health risks associated with exposure to parabens, we developed a simultaneous analytical method to quantify 4 parabens (methyl, ethyl, propyl, and butyl) in human urine, by using solid-phase extraction and high-performance liquid chromatography coupled with triple quadrupole mass spectrometry. This method showed good specificity, linearity ($R^2$ > 0.999), accuracy (92.2-112.4%), precision (0.9-9.6%, CV), and recovery (95.7-102.0%). The LOQs for the 4 parabens were 1.0, 0.5, 0.2, and 0.5 ng/mL, respectively. This method could be used for quick and accurate analysis of a large number of human samples in epidemiological studies to assess the prevalence of human exposure to parabens.

• Journal of Environmental Health Sciences
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• v.42 no.3
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• pp.213-223
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• 2016

Objectives: This study was designed to assess the level of physical exposure to heavy metals among residents who live around a Chungcheongnam-do Province industrial complex and to provide baseline data on the effects and harms of heavy metals on the human body by comparing their exposure levels to those of people from control regions. Methods: We measured blood lead and cadmium levels and urine mercury and chromium levels and conducted a survey among 559 residents from the affected area and 347 residents of other areas. Results: Blood lead and cadmium levels and urine mercury levels were significantly higher in the case region than among those in the control region (p=0.013, p<0.001, p<0.001, respectively). In the thermoelectric power plant area, blood cadmium and urine mercury levels were significantly higher than in the control region (p<0.001, p<0.001, respectively). In the steel mill and petrochemical industry areas, blood cadmium level was significantly higher than that in the control region (p<0.001). Dividing groups by the reference level of blood cadmium ($2{\mu}g/L$), the odds ratios between the case and control regions were 2.56 (95% CI=1.83-3.58), 3.11 (95% CI=2.06-4.71) for the thermoelectric power plant area, 1.78 (95% CI=1.19-2.65) for the steel mill area and 4.07 (95% CI=2.40-6.89) for petrochemical industry area. Conclusion: This study showed that the levels of exposure to heavy metals among residents living near a Chungcheongnam-do Province industrial complex were significantly higher than those in the control region. This seems to be attributable to exposure to heavy metals emissions from the industrial complex. Further research and safety measures are required to protect residents' health.

• Progress in Medical Physics
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• v.8 no.2
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• pp.103-109
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• 1997

Recently NMR analyses of human urine show that the four proton NMR signals between 7 ppm and 8 ppm more frequently appear in stomach cancer urine than in normal and other diseased urine. These four NMR signals are found to be given by 7.25, 7.38, 7.63 and 7.80 in ppm. The calculations of spin coupling constants show that the NMR signals are identified as the four aromatic proton NMR signals of m-hydroxyphenyl rather than the ones of p-hydroxyphenyl. With this frequent appearance in the cancer urine, the cancer diagnosis has been made. In the present work, an attempt is made to determine the total volume susceptibility of the four aromatic proton NMR signals of the excreted m-hydroxyphenyl. The results of the attempt show that the volume susceptibilities of the above given values are as follows: 10.01${\times}$10$\^$-6/, 10.07${\times}$10$\^$-6/, 10.19${\times}$10$\^$-6/ and 10.27${\times}$10$\^$-6/. Hence its total susceptibility is 10.27${\times}$10$\^$-6/.

• Journal of agricultural medicine and community health
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• v.18 no.2
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• pp.153-160
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• 1993

Health complaints among vinylhouse workers in Sungjoo county, Kyungpook province led to the investigation of heavy metal levels of air, soil and humans as well as physical conditions of the vinylhouse. The average temperature and humidity inside the vinylhouse were 8 higher and 10% point lower, respectively, as compared to the outside. While discomfort index(D. I.) outside was pleasant level(69.2), D. I. inside was 82 at which point 100% of people feels discomfort. Cadmium concentration of soils inside the vinylhouse(0.116 mg/kg) was 1.8 times higher than the soils outside. Arsenic concentration of soils inside the vinylhouse(4.882 mg/kg) was only slightly higher than the soils outside(4.182 ng/kg). However, both heavy metal concentrations detected in soils inside or outside the vinylhouse were within the normal range. Analysis of 10 air samples taken inside the vinylhouse showed that only one sample had a cadmium concentration above the detectable level and the rest of samples were below the detectable levels. While there were no difference of arsenic concentrations in urine between male and female, cadmium concentrations in urine samples of female (3.31 ug/l) was slightly higher than male(2.38 ug/l). Age-dependent increases of cadmium concentrations in urine samples were also observed. However, there was no concentration difference of these heavy metals in urine between vinylhouse workers and non-vinylhouse workers. Urine concentrations of cadmium and arsenic detected from vinylhouse workers or non-vinylhouse workers were within the normal range. The present study represents a first attempt to evaluate physical and environmental risk factors of the vinylhouse affecting the vinylhouse farmer's health. The study revealed that, while physical conditions of the vinylhouse such as temperature and humidity are the possible factors associated with the farmer's complaints, environmental contamination as judged from heavy metal levels in soil, air and humans is not a risk factor contributing to the vinylhouse farmer's health problem.

• Mass Spectrometry Letters
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• v.5 no.4
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• pp.104-109
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• 2014

Nonmedical use of prescription stimulants such as methylphenidate (MPH) and amphetamine (AP) by normal persons has been increased to improve cognitive functions. Due to high potential for their abuse, reliable analytical methods were required to detect these prescription stimulants in biological samples. A direct injection liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and implemented for simultaneous determination of MPH, AP and their metabolites ritalinic acid (RA) and 4-hydroxyamphetamine (HAP) in human urine. Urine sample was centrifuged and the upper layer ($100{\mu}L$) was mixed with $800{\mu}L$ of distilled water and $100{\mu}L$ of internal standards ($0.2{\mu}g/mL$ in methanol). The mixture was then directly injected into the LC-MS/MS system. The mobile phase was composed of 0.2% formic acid in distilled water (A) and acetonitrile (B). Chromatographic separation was performed by using a Capcell Pak MG-II C18 ($150mm{\times}2.0mm$ i.d., $5{\mu}m$, Shiseido) column and all analytes were eluted within 5 min. Linear least-squares regression with a 1/x weighting factor was used to generate a calibration curve and the assay was linear from 20 to 1500 ng/mL (HAP), 40-3000 ng/mL (AP and RA) and 2-150 ng/mL (MPH). The intra- and inter-day precisions were within 16.4%. The intra- and inter-day accuracies ranged from -15.6% to 10.8%. The limits of detection for all the analytes were less than 4.7 ng/mL. The suitability of the method was examined by analyzing urine samples from drug abusers.

• Childhood Kidney Diseases
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• v.10 no.1
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• pp.65-71
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• 2006

Idiopathic renal hypouricemia is a disorder characterized by impaired urate handling in the renal tubules. Most patients with hypouricemia are asymptomatic and are found incidentally, but the condition is known to be at high risk for exercise-induced acute renal failure or urolithiasis. URAT1 protein encoded by SLC22A12 gene has been identified recently as a urate/anion exchanger in the human kidney. Inactivation mutations in SLC22A12 gene have been shown to cause renal idiopathic hypouricemia. We experienced a 3-year-old boy who presented with persistent orange-colored urine since infancy. His urine contained many uric acid crystals, while the serum showed hypouricemia(0.7 mg/dL). The fractional excretion of uric acid was increased to 41.7%. SLC22a12 gene analysis revealed W258X homozygote alleles. Renal hypouricemia must be included in the differential diagnosis of red-urine and SLC22A12 gene analysis is recommended in idiopathic renal hypouricemia.

• Analytical Science and Technology
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• v.17 no.5
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• pp.401-409
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• 2004

The 7-keto-DHEA-acetate is converted to 7-keto-DHEA, a metabolite of DHEA, and similar to its metabolism. We studied the metabolite M3, M4, and M5 of 7-keto-DHEA-acetate. The estimated molecular weight of M3 and M4 was 304 which were supposed to have more 3 hydroxyl and/or ketone groups. We could know that M3 is the 7-OH-DHEA which has the hydroxyl groups on 3 and 7-carbon and a ketone group on 17-carbon. In case of M4, it is the 7-oxo-diol metabolite which has the hydroxyl groups on 3 and 17-carbon and a ketone group on 7-carbon. The M5 was supposed that the molecular weight is 320 and has the three hydroxyl groups on 3, 6, and 16 carbon and the ketone group on 17-carbon. After dosing, 7-OH-DHEA showed the maximum urine flow in human urine after 5 hr and decreased rapidly. But we could find it until 58 hr why is a higher remaining substance.

• Journal of the Korean Chemical Society
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• v.61 no.2
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• pp.51-56
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• 2017

N-nitrosamines are the nitroso compounds which are produced by nitrosation reactions of the secondary amine and nitrite under acidic conditions. Approximately 300 species of N-nitrosamine have been tested for carcinogenicity in laboratory experiments, with 90% of them demonstrated carcinogenic effects different animal species, including higher primates. In 1978, IARC classified NDMA and NDEA as Group 2A, and NDPA, NDBA, NPIP, NPYR and NMOR as Group 2B. In this study, we established pretreatment and analytical method for N-nitrosamines (NDMA, NDEA, NMEA, NDPA, NDBA, NPIP, NPYR and NMOR) in human urine for biological monitoring of N-nitrosamines. The analytes were extracted using solid phase extraction (SPE), then quantitative analysis was performed by LC-(APCI)-MS/MS. The accuracies of the established method were between 85.8~108.7% and precisions were lower than 20%. The limit of detection (LOD) were between 0.0002 (NDBA) and 0.0793 (NDMA) ng/ml. The linearity obtained was satisfying for the 8 N-nitrosamines, with a coefficient of determination ($r^2$) higher than 0.999. The mean concentrations of N-nitrosamines in the urine were 2.645 mg/g creatinine for NDMA, 0.067 mg/g creatinine for NDEA, 0.009 mg/g creatinine for NMEA, 0.011 mg/g creatinine for NDBA, 0.271 mg/g creatinine for NPIP and 0.413 mg/g creatinine for NPYR. NDPA and NMOR were not detected. It can be used as a instrumental methodology for evaluation and risk assessment of human exposure to N-nitrosamines for the further research.

• Journal of Preventive Medicine and Public Health
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• v.35 no.4
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• pp.282-286
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• 2002

Objectives : The level of 4-hydroxyproline (4-Hyp) in human urine was measured using high performance liquid chromatography (HPLC) with a fluorescence detector. This method is useful for medical examinations and investigating the radicals induced by physical, chemical, mental stresses. This method is superior to many published several methods in terms of its low cost and ability to analyze many samples. Methods : The urine from workers in a tire manufacturing company (22 male pre- and post-shift workers) and 18 office-workers as controls were analyzed. Data concerning age, the cumulative drinking amount and the cumulative smoking amount was collected with a questionnaire. The optimum applied amount of dansyl-Cl, the optimum reaction temperature and time, the recoveries and the optimum pH of the eluent and buffer were determined.4-Hyp from human urine was derivatized with dansyl-Cl (dimethylamino-naphthalene-1-sulfonyl chloride) after removing the a-amino acid by a treatment with phthalic dicarboxaldehyde (OPA) and cleaned with Bond Elut C18 column. The 4-Hyp derivatives were separated on a reversed phase column by gradient elution with a phosphate buffer (5 mmol, pH 8.0) and acetonitrile, and detected by fluorescence measurements at 340 nm (excitation) and 538 nm (emission). Results : The detection limit for the urinary free 4-Hyp was $0.364{\mu}mol/l$. The recovery rate of 4-Hyp was 99.7%, and the effective pH of the phosphate buffer and borate buffer were 3.0 and 8.0, respectively. From statistical analysis, age, drinking and smoking did not affect the urinary free 4-Hyp in both the controls and workers. The range of urinary 4-Hyp in the controls, pre-shift, and post-shift workers were 0.33-16.44, N.D-49.06, and $0.32-56.27{\mu}mol/l$. From the pared-sample t-test, the urinary 4-Hyp levels in post-shift workers ($11.82{\pm}6.73\;nmmol/mg\;Cre$) were 2-fold higher than in pre-shift workers ($5.36{\pm}5.53\;nmol;/mg\;Cre$) and controls ($4.91{\pm}4.89\;nmol;/mg\;Cre$). Conclusions : This method was developed with high sensitivity, accuracy, and precision. The present method was effectively applied to analyze the urinary free 4-Hyp in both controls and workers.

• Journal of the Korean Chemical Society
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• v.33 no.3
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• pp.332-334
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• 1989