• Progress in Medical Physics
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• v.20 no.1
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• pp.21-29
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• 2009

Breast cancer is the most common form of cancer among korean woman. Therefore, the early detection activities of breast cancer such as breast self-examinations, clinical breast examinations, mammography are important. A yearly mammography examination has been recommended for women aged 40 and older for the early detection of breast cancer in asymptomatic periods. However, the glandular tissue of breast is the most radiation-sensitive tissue, and the determination of average glandular dose (AGD) forms an important part of the quality control of the mammographic systems. Because of the difficulty of estimating AGD directly, it is often estimated from the measurements of the incident air kerma and by applying the appropriate conversion factors. The primary objective of this study was to standardize the method of measuring AGD. The secondary objective was to evaluate the relationships between AGD per various composition and thickness of the breast using Monte Carlo simulations. As a result, we standardized the method of measuring AGD according to International Atomic Energy Agency (IAEA) guidelines (CoP: an international code of practice). Overall, AGD for mammographic practice in Korea was less than 3.0 mGy recommended by the Korea Food and Drug Adminstration (KFDA) protocol, and Korean Institute for Accreditation of Medical Image (KIAMI). The measured and simulated AGD for a given condition were calculated as 1.7 and 1.6 mGy, respectively. For the AGDs obtained, there was no significant difference between them. The simulated AGD was dependent on the fraction of glandular tissue of the breast. The AGD increases with increasing of the breast glandularity due to increasing absorption of low energy photons. The AGD also increases as a function of breast thickness. In conclusion, the results of this study could be used as a baseline to establish a reference level of radiation dose in mammography.

• Tuberculosis and Respiratory Diseases
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• v.60 no.2
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• pp.171-179
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• 2006

Background : Despite the emerging danger of MDR-TB to human beings, there have only been a limited number of drugs developed to treat MDR-TB since 1970. This study investigated the cross-resistance rate between rifampicin (RFP) and rifabutin (RBU) in order to determine the efficacy of rifabutin in treating MDR-TB. In addition, the results of rifabutin were correlated with the rpoB mutations, which are believed to be markers for MDR-TB and RFP resistance. Methods : The MICs of RBU were tested against 126 clinical isolates of MDR-TB submitted to the clinical laboratory of National Masan TB Hospital in 2004. Five different concentrations ($10-160{\mu}g/ml$) were used for the MICs. The detection of the rpoB mutations was performed using a RFP resistance detection kit with a line probe assay(LiPA), which contains the oligonucleotide probes for 5 wide type and 3 specific mutations (513CCA, 516GTC, and 531TTG) The rpoB mutation was determined by direct sequencing. Results : The rate of cross-resistance between RFP and RBU was 70.5%(74/105) at $20{\mu}g/ml$ RBU(ed note: How much RFP?) Most mutations (86.3%) occurred in the 524~534 codons. The His526Gln, His526Leu, Leu533Pro, Gln513Glu, and Leu511Pro mutations(Ed note: Is this correct?) were associated with the susceptibilty to RBU. Conclusion : Based on the cross-resistance rate between RFP and RBU, RBU may be used effectively in some MDR-TB patients. Therefore, a conventional drug susceptibility test for RBU and a determination of the critical concentration are needed. However, rpoB gene mutation test may be have limited clinical applications in detecting RBU resistance.

• Pediatric Infection and Vaccine
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• v.12 no.1
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• pp.75-85
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• 2005

Purpose : Fungal infection is one of the important causes of morbidity and mortality in patients with hematologic malignancies. Amphotericin B(ABV) and itraconazole(ITZA) have been used as the standard empirical antifungal therapy in neutropenic patients with acute leukemia who have persistent fever that does not respond to antibiotic therapy. ABV is an antifungal drug associated with side effects such as fever and chills, symptoms which may be mediated by pro-inflammatory cytokines such as interleukin-$1{\beta}$(IL-$1{\beta}$) and tumor necrosis factor-${\alpha}$(TNF-${\alpha}$). We assessed modulation of these pro-inflammatory cytokines as well as the anti-inflammatory cytokines(IL-4, IL-1Ra) by ABV and ITZA. Methods : From March 2004 to February 2005, a total of 30 episodes from acute leukemia patients with febrile neutropenia were analyzed for this study. They were randomly allocated to receive intravenous ABV or ITZA for 14 days. Clinical responses were evaluated at the completion of therapy, and cytokine IL-$1{\beta}$, TNF-${\alpha}$, IL-4, and IL-1Ra were measured for determination to know the correlation between two antifungal agents and inflammatory cytokines. Results : Empirical antifungal agents were given to 37 patients(ABV 20, ITZA 17), and 30 patients(ABV 15, ITZA 15) were evaluable for efficacy. White blood cell and absolute neutrophil count in the group treated with ITZA increased early days of treatment, so the duration of neutropenia in ITZA group is shorter. Serum creatinine level is lower in ITZA group than in ABV group but this is not statistically significant. There was no significant difference in response rate between two groups. The IL-$1{\beta}$ was increased in ABV treatment group and the ratio of IL-1Ra/IL-$1{\beta}$ is markedly decreased in ABV treatment group while increased in ITZA group. Conclusion : ITZA and ABV have at least equivalent efficacy as empirical antifungal therapy in neutropenic children with acute leukemia. However ITZA is associated with significantly less toxicity in clinical and molecular aspects.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.174-179
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• 2002

A simple and sensitive analysis method based on reverse phase (RP) HPCL with flourescence detector was developed for simultaneous determination of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), bisphenol F diglycidyl ether (BFDGE), and their degradation products, $BADGE{\cdot}H_2O$, $BADGE{\cdot}2H_2O$, $BFDGE{\cdot}H_2O$, $BFDGE{\cdot}2H_2O$, $BADGE{\cdot}HCl{\cdot}H_2O$, $BADGE{\cdot}HCl$, $BADGE{\cdot}2HCl$, $BFDGE{\cdot}HCl{\cdot}H_2O$, $BFDGE{\cdot}HCl$ and $BFDGE{\cdot}2HCl$, which were hydrolyzed and chlorinated forms of BADGE and BFDGE, in canned foods and food simulants. These compounds were identified by GC/MSD with $MSTFA-NH_4I-DTE$ derivatization. Recovery study was performed at each 100 ng/mL levels of BPA, BPF, BADGE and BFDGE added to canned foods and food simulants. This method was resulted in recovery of $90{\sim}114%$ with relative standard deviation of $4.1{\sim}7.0%$, detection limits of $6{\sim}11$ ng/mL and quantitation limits of $12{\sim}18\;ng/mL$. Calibration curves were linear with correlatin coefficients of 0.997 for BPF, 0.996 for BPA, 0.9987 for BFDGE, and 0.9989 for BADGE.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.141-150
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• 2002

Owing to a need for simple extraction and purification for analysis of water soluble vitamins in food samples by RP-HPLC with UV-detector, the methods of bromelain and protease hydrolysis and $C_{18}$ Sep-Pak solid phase extraction were employed. The recoveries of standard water soluble vitamins by the bromelain and protease hydrolysis and $C_{18}$ Sep-Pak solid phase extraction were significantly high compared to AOAC methods in most of vitamins. The contents of pyridoxal determined with protest in the pork was similar, but in the bromelain hydrolysis and AOAC method, was high compared to the results of reference. The niacinamide, thiamin and riboflavin determined with bromelain and protease hydrolysis showed similar values to the results of references. In the potato, pyridoxamine was detected in the AOAC method, which was not detected in the bromelain and protease hydrolysis methods. Pyridoxal contents in the protease hydrolysis and AOAC methods were very similar to the results of references. The recoveries of fortified standard vitamins in food samples were significantly high and accurate compared to those of AOAC methods. The extraction and purification with $C_{18}$ Sep-Pak solid extractor might be considered superior method for the determination of water soluble vitamins in food samples.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.1082-1090
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• 2005

Jocheong was prepared by adding Lentinus edodes extract to improve its quality and to give some functional properties. Contents of crude protein, ash and crude lipid were similar to those of control, while carbohydrate content was decreased. Total mineral content were $1,916.03\~2,674.24mg/kg$ that was no difference between test samples. From HPLC determination of free sugars, Jocheong was found to contain maltose as the highest sugar, followed by glucose and fructose. In amino acid analysis, seventeen amino acid were identified and quantified. Glutamic acid in Jocheong was major amino acid. The major fatty acids in Jocheong $(0\%,\;control)$ were linoleic acid, palmitic acid, oleic acid, myristic acid and caproic acid. There was no significant differences in fatty acid composition, pH and reducing sugar content among the Jocheong samples. The viscosity and solid contents tended to decrease with the addition of Lentinus edodes extract. Increasing the ratio of mushroom extract in Jocheong tended to decrease the lightness, yellowness and redness in Hunter's color value. Although sensory value decreased with increasing Lentinus edodes extracts, use of mushroom extracts (7: 3; saccharification liquids: Lentinus edodes extracts) is recommended for making Jocheong.

• Journal of Food Hygiene and Safety
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• v.36 no.4
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• pp.298-309
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• 2021

In this study we sought to develop a simultaneous analysis method for cis-bixin and cis-norbixin, the main components, to detect annatto pigment in food. To establish the optimal test method, the HPLC analysis methods of the European Food Safety Authority (EFSA), Japan's Ministry of Health, Labor and Welfare (MHLW), and National Institute of Food and Drug Safety Evaluation (NIFDS) were compared and reviewed. In addition, a new pretreatment method applicable to various foods was developed after selecting conditions for simultaneous high-performance liquid chromatography (HPLC) analysis in consideration of linearity, limit of detection (LOD), limit of quantification (LOQ), and analysis time. The HPLC analysis method of NIFDS showed the best linearity (R² ≥ 0.999), exhibiting low detection and quantification limits for cis-norbixin and cis-bixin as 0.03, 0.05 ㎍/mL, and 0.097, 0.16 ㎍/mL, respectively. All previously reported pretreatment methods had limitations in various food applications. However, the new pretreatment method showed a high recovery rate for all three main food groups of fish meat and meat products, processed cheese and beverages. This method showed an excellent simultaneous recovery rate of 98% or more for cis-bixin and cis-norbixin. The HPLC analysis method with a new pretreatment method showed high linearity with a coefficient of determination (R²) of 1 for both substances, and the accuracy (recovery rate) and precision (%RSD) were 98% and between 0.4-7.9, respectively. From this result, the optimized analytical method was considered to be very suitable for the simultaneous analysis of cis-bixin and cis-norbixin, two main components of annatto pigment in food.

• Journal of Food Hygiene and Safety
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• v.36 no.1
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• pp.24-33
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• 2021

For this study, we surveyed concentrations of 8 mycotoxins (aflatoxin B1, B2, G1, G2, ochratoxin A, fumonisin B1, B2 and zearalenone) in agricultural products used for food and medicine by liquid chromatography-tandem mass spectrometry and conducted a risk assessment. Samples were collected at the Yangnyeong Market in Seoul, Korea, between January and November 2019. Mycotoxins were extracted from these samples by adding 0.1% formic acid in 50% acetonitrile and cleaned up by using an ISOLUTE Myco cartridge. The method was validated by assessing its matrix effects, linearity, limit of detection (LOD), limit of quantification (LOQ), recovery and precision using four representative matrices. Matrix-matched standard calibration was used for quantification and the calibration curves of all analytes showed good linearity (r2>0.9999). LODs and LOQs were in the range of 0.02-0.11 ㎍/kg and 0.06-0.26 ㎍/kg, respectively. Sample recoveries were from 81.2 to 118.7% and relative standard deviations lower than 8.90%. The method developed in this study was applied to analyze a total of 187 samples, and aflatoxin B1 was detected at the range of 1.18-7.29 ㎍/kg (below the maximum allowable limit set by the Ministry of Food and Drug Safety, MFDS), whereas aflatoxin B2, G1 and G2 were not detected. Mycotoxins that are not regulated presently in Korea were also detected: fumonisin (0.84-14.25 ㎍/kg), ochratoxin A (0.76-17.42 ㎍/kg), and zearalenone (1.73-15.96 ㎍/kg). Risk assessment was evaluated by using estimated daily intake (EDI) and specific guideline values. These results indicate that the overall exposure level of Koreans to mycotoxins due to the intake of agricultural products used for food and medicine is unlikely to be a major risk factor for their health.