• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.320-323
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• 2001

A computer simulation was performed to distinguish quantitatively a color reaction in a urine analysis systems by using the spectral power distribution of LEDs. the spectral reflectance of a urine strip. and the spectral sensitivity of photodiode. The CIE tristimulus values and CIE chromaticity coordinates ware modified to be conformable with real color reactions in a urine strips. Results on color simulation showed a of real color in comparison with those obtained by Colorimeter CM2C(Color Savvy).

• 분석과학
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• 제33권1호
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• pp.23-32
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• 2020

Methamphetamine (MA) is the most common and available drug of abuse in Korea and its primary metabolite is amphetamine (AP). Detection of AP derivatives, such as MA, AP, phentermine (PT), MDA, MDMA, and MDEA by the use of immunoassay screening is not reliable and accurate due to cross-reactivity and insufficient specificity/sensitivity. Therefore, the analytical process accepted by most urine drug-testing programs employs the two-step method with an initial screening test followed by a more specific confirmatory test if the specimen screens positive. In this study, a gas chromatography-mass spectrometric (GC-MS) method was developed and validated for confirmation of MA and AP in human urine. Urine sample (500 µL) was added with N-isopropylbenzylamine as internal standard and ethyl chloroformate as a derivatization reagent, and then extracted with 200 µL of ethyl acetate. Extracted samples were analysed with GC-MS in the SIM/ Scan mode, which were screened by Cobas c311 analyzer (Roche/Hitachi) to evaluate the efficiency as well as the compatibility of the GC-MS method. Qualitative method validation requirements for selectivity, limit of detection (LOD), precision, accuracy, and specificity/sensitivity were examined. These parameters were estimated on the basis of the most intense and characteristic ions in mass spectra of target compounds. Precision and accuracy were less than 5.2 % (RSD) and ±14.0 % (bias), respectively. The LODs were 3 ng/mL for MA and 1.5 ng/mL for AP. At the screening immunoassay had a sensitivity of 100% and a specificity of 95.1 % versus GC-MS for confirmatory testing. The applicability of the method was tested by the analysis of spiked urine and abusers' urine samples.

• 한국환경보건학회지
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• 제33권5호
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• pp.386-391
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• 2007

Mercury contamination and its health effects have become major concern of environmental health study in Korea. Mercury exposure of some group were investigated to get the accurate data for policy making and study. About 2,000 children at 26 elementary schools participated in this survey to evaluate the exposure levels and to investigate main exposure source of mercury. Analysis of mercury levels in the whole blood and urine samples were conducted and questionnaire survey was done about the factors influencing exposures simultaneously. Mercury exposure levels of domestic children were N.D. to 17.26 ppb in blood, 0.17 to $21.67{\mu}g/g$-creatinine in urine. The mean(arithmetic) levels are 2.42 ppb in blood and $2.53{\mu}g/g$-creatinine in urine. Both of them were below the recommendation levels of US EPA and German CHBM I $5.8{\mu}g/l$ and $5{\mu}g/l$ in blood, $5{\mu}g/g$-creatinine of German CHBM I in urine. But 1%, 0.51% of levels in blood exceed the level of CHBM I and US EPA, 8%, 0.85% of children were over the level of CHBM I and CHBM II in urine. Multi-valuable regression analysis showed that the existence of road near the residence in addition to the preference for fish have significance with blood mercury exposure level of domestic children. The existence of factory near the house and the experience of dental amalgam treatment had statistical relations with urine mercury level.

• Clinical and Experimental Pediatrics
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• 제49권3호
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• pp.329-331
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• 2006

알캅톤뇨증은 상염색체 열성으로 유전하는 드문 질환으로 homogentisic acid oxidase 결핍에 의해 homogentisic acid가 체내 축적되고 소변으로 다량 배설되는 대사 이상 질환이다. 주로 도미니카 공화국과 슬로바키아에서 보고되고 있으나 한국에는 아직 보고된 바 없다. 증상으로는 소아 때에는 주로 배뇨 후 시간이 지나면 소변 색이 검어지는 특징이 보이고, 나이가 들면서 연골과 결체 조직의 착색, 관절염, 갈색증, 심장 질환, 신장 질환 등이 발생할 수 있다. 특별히 효과가 입증된 치료제는 없는 것으로 보고되고 있고, 진단은 뇨유기산분석을 통해 할 수 있다. 저자들은 내원 당시 13개월이었던 여자 환아에서 기저귀에 묻은 소변이 시간이 지나면서 연분홍 갈색빛을 보여 시행한 뇨유기산분석에서 homogentisic acid (normal range <2 mmol/molCr)가 1,158.3 mmol/molCr로 현저한 증가 소견을 보여 보고하는 바이다. 재검사에서도 역시 910.7 mmol/molCr 로 증가된 소견을 보였으며 환아 신체 어디에서도 연갈색이나 검은색의 착색된 부위를 찾을 수 없었다. 환아는 현재 ascorbic acid 투여하며 추적관찰 중이다.

• 분석과학
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• 제34권2호
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• pp.68-77
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• 2021

Cannabis is one of the most abused drugs in Korea. The main psychoactive component in cannabis, Δ9-tetrahydrocannabinol, is metabolized to 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) and THCCOOH-glucuronide (THCCOOH-glu) in the human liver, whereby the amount of THCCOOH-glu found in urine is twice as high as that of THCCOOH. The analytical process adapted by the majority of urine drug-testing programs involves a two-step method consisting of an initial immunoassay-based screening test followed by a confirmatory test if the screening test result is positive. In this study, a qualitative gas chromatography-mass spectrometry (GC-MS) method was developed and validated for the detection of THCCOOH in human urine, where THCCOOH-glu was converted into THCCOOH by alkaline hydrolysis. For purification of the urine extract prior to instrumental analysis, high-speed centrifugation was used to minimize interference. In addition, an injection-port derivatization method using ethyl acetate and N,O-bis(trimethylsilyl)-trifluoroacetamide containing 1 % trimethylchlorosilane was employed to reduce the time required for derivatization, and an aliquot of the final solution was injected into the GC-MS. The method was validated by measuring the selectivity, limit of detection (LOD), and repeatability. The sensitivity, specificity, precision, accuracy, Kappa, F-measure, false positive, and false negative rate were determined by comparing the GC-MS results with those obtained using the immunoassay. The LOD was determined to be 0.32 ng/mL, while the repeatability was within 9.1 % for THCCOOH. Furthermore, a comparison study was carried out, whereby the screening immunoassay exhibited a sensitivity of 86.4 % and a specificity of 100 % compared to GC-MS. The applicability of the developed method was examined by analyzing spiked urine and forensic urine samples obtained from suspected cannabis abusers (n = 221).

• Journal of Yeungnam Medical Science
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• 제37권2호
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• pp.112-121
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• 2020

Background: Vancomycin-resistant Enterococcus (VRE) has become more common in nosocomial infections, especially in urine samples. However, until now, no treatment regimen has been proven to effectively eradicate urine VRE colonization. Therefore, to evaluate the efficacy of doxycycline in eradicating urine VRE and shortening VRE isolation period, we compared VRE colony detection period between doxycycline-treated and untreated patients. Methods: A retrospective cohort study of 83 patients with VRE colonization in urine cultures was conducted at a tertiary academic hospital from January 2011 to February 2018. Kaplan-Meier survival analysis was used to evaluate eradication rates in the treatment and non-treatment groups. Factors affecting urine VRE colonization persistence were analyzed by multiple logistic regression analysis. Results: The overall rate of VRE eradication during the entire hospital stay was higher in the doxycycline treatment group (90.5%) than in the non-treatment group (58.1%, p=0.014). Survival analysis showed that the 5-, 10-, and 20-day cumulative eradication rates were 78.3%, 100%, and 100% in the doxycycline treatment group, and 18.5%, 45.7%, and 67.8% in the non-treatment group, respectively, thereby indicating that eradication rates were higher in the doxycycline treatment group than in the non-treatment group (p<0.001). Only doxycycline treatment was shown to affect urine VRE colonization persistence in multivariate logistic regression analysis. Conclusion: Doxycycline treatment enhanced the eradication rate of urine VRE colonization and appeared to be useful in shortening VRE isolation period.

• Journal of Yeungnam Medical Science
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• 제40권4호
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• pp.373-380
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• 2023

Background: The association between dental amalgam fillings and urine mercury concentrations was investigated in this study to assess the health risks associated with dental amalgams. Methods: This cross-sectional study included 99 women in their 20s who visited the dental clinic in Daegu, Korea. The 99 participants were composed of 68 subjects who had dental amalgam fillings (exposure group) and 31 subjects who did not have dental amalgam fillings (nonexposure group). Oral examinations were conducted by a single dental hygienist, sociodemographic features were investigated as confounding variables, and urine mercury concentrations were measured using an automatic mercury analyzer. Results: The mean±standard deviation of the urine mercury concentrations of the exposure and nonexposure groups were 1.50±1.78 ㎍/g creatinine and 0.53±0.63 ㎍/g creatinine, respectively. The exposure group showed significantly higher levels than the nonexposure group (p<0.01). The urine mercury concentration significantly increased with an increase in the number of teeth filled with amalgam, cavity surfaces involved, and number of defective amalgam fillings, and according to the latest exposure time (p<0.001). In the multiple regression analysis of amalgam-related factors and urine mercury concentrations after correction for confounding factors, the urine mercury concentration in the group with six or more amalgam-filled teeth, 11 or more cavity surfaces, and two or more defective amalgams was significantly higher than that in the nonexposure group (p<0.001). Conclusion: According to this study, exposure to dental amalgams was confirmed to significantly affect urine mercury concentrations.

• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1133-1138
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• 2014

Ultrahigh performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI- MS/MS) provides a high-speed method to screen a large number of samples for small molecules with specific properties. In this study, UPLC-ESI-MS/MS with multiple reaction monitoring (MRM) was employed to screen urinary phospholipid (PL) content for biomarkers of prostate cancer. From lists of urinary PLs structurally identified using nanoflow LC-ESI-MS/MS, 52 PL species were selected for quantitative analysis in urine samples between 22 cancer-free urologic patients as controls and 45 prostate cancer patients. Statistical treatment of data by receiver operating characteristic (ROC) analysis yielded 14 PL species that differed significantly in relative concentrations (area under curve (AUC) > 0.8) between the two groups. Among PLs present at higher levels in prostate cancer urine, phosphatidylcholines (PCs) and phosphatidylinositols (PIs) constituted the major head group PLs (3 PCs and 7 PIs). For technical reasons, PL species of low abundance may be underrepresented in data from UPLC-ESI-MS/MS performed in MRM mode. However, the proposed method enables the rapid screening of large numbers of plasma or urine samples in the search for biomarkers of human disease.

• Tuberculosis and Respiratory Diseases
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• 제73권4호
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• pp.210-218
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• 2012

Background: The level of urine cotinine is an indicator of tobacco smoke exposure. The purpose of this study is to investigate urine cotinine for the purpose of assessing the smoking status of Korean smokers and non-smokers exposed to tobacco smoke. Methods: The subjects were identified from the 2007-2009 and the 2010 data sets of the Korea National Health and Nutrition Examination Survey (KNHANES). They were assigned as non-smokers, current smokers and ex-smokers. Non-smokers were also divided into three subset groups according to the duration of smoke exposure. Each group was stratified by gender prior to analysis. Results: The median value of urine cotinine in the male current smokers was 1,221.93 ng/mL which was the highest among all groups. The difference between levels of urine cotinine for male and the female groups was statistically significant (p<0.01). In the female group, passive smoke exposure groups reported higher urine cotinine levels than non-exposure groups (p=0.01). The cutoff point for the discrimination of current smokers from non-smokers was 95.6 ng/mL in males and 96.8 ng/mL in females. The sensitivity and specificity were 95.2% and 97.1%, respectively, in males, 96.1% and 96.5% in females. However, the determination of urine cotinine level was not useful in distinguishing between passive smoke exposure groups and non-exposure groups. Conclusion: Urine cotinine concentration is a useful biomarker for discriminating non-smokers from current smokers. However, careful interpretation is necessary for assessing passive smoke exposure by urine cotinine concentration.

• Yonsei Medical Journal
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• 제63권1호
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• pp.66-71
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• 2022

Purpose Proteinuria is a clinical sign of adverse cardiovascular outcomes, including stroke. We aimed to assess the relationship between proteinuria and the occurrence of cerebral infarction. Materials and Methods In total, 208854 Koreans who participated in the 2009 medical examination were followed up until 2013 using the database of the National Health Insurance Service. The results of urine dipstick tests were utilized to assess proteinuria as absent, 1+, 2+, or ≥3+. The International Classification of Diseases code 163 was used to document cerebral infarction. Results Between 2009 and 2013, 2383 cases (1.14%) of cerebral infarction occurred during 912772.9 person-years of follow-up. Hazard ratios for incident cerebral infarction increased with inceasing amounts of urine protein from 1.53 (1.23-1.90) in group 2 (1+), 1.67 (1.22-2.28) in group 3 (2+), and 2.66 (1.79-3.96) in group 4 (≥3+), compared to the reference group with little to no detectable urine protein (p<0.001, respectively). Conclusion An increase in urine protein levels was significantly related to the risk of developing cerebral infarction. Our results suggest that proteinuria might be a potential risk factor for cerebral infarction and that urine dipstick test analysis may be clinically useful for predicting stroke.