Escherichia coli가 생성하는 CTX-M형 Extended-Spectrum β-lactamase

황현용,박재선,배일권,이유내,정석훈 고신대학교의과대학 2007 고신대학교 의과대학 학술지 Vol.22 No.1

Background β-lactam antibiotics have been broadly used to treat gram negative microorganisms, which resulted in the occurrence of antibiotics-resistant microorganisms. Microorganisms mainly achieve resistance to antibiotics by producing β-lactamases that decrease activities of antibiotics. Various types of CTX-M extended-spectrum β-lactamases (ESBLs) have been known since CTX-M-1 and CTX-M-2 ESBLs were reported in 1996. CTX-M-14 β-lactamases were reported in Seoul and Cheju Island of Korea in 2001. Until now, there has been no CTX-M type ESBL report in Korea. So, the research on the identification of the CTX-M type ESBLs and their genetic types using E. coli resistant to or intermediate to cefotaxime were performed. Methods Total of 365 isolates of Escherichia coli from Kosin University Hospital in Busan for a six-month periods were examined. Disk diffusion test for antibiotics susceptibility, double disk synergy test for confirming ESBL, polymerase chain reaction (PCR) for identifying genetic types of CTX-M ESBLs, minimal inhibitory concentration tests of CTX-M ESBLs and isoelectricfocusing (IEF) for measuring the pI of β-lactamase were tested using E. coli resistant or intermediate to cefotaxime. Results Thirty one out of 365 E. coli isolates were resistant to or intermediate to cefotaxime. Fifteen out of 31 E. coil isolates resistant or intermediate to cefotaxime were positive to double disk synergy, 6 isolates of which were positive to PCR by CTX-M-2F and CTX-M-2R primers. MICs of cefotaxime to isolates carrying CTX-M ESBL were as high as ≥128 mg/L. MICs of ceftazidime were relatively low as 2-64 mg/L. Isoelectric point was 8.4 for bla_(CTX-M-3) and 8.6 for bla_(CTX-M-15), respectively. Conclusion CTX-M-3 β-lactamase and CTX-M-15 β-lacatamase found in this study are genetically different from previous types of CTX-M-type ESBLs in Korea. Also newly found CTX-M type ESBLs are expected to cause difficulties in the treatment of infections. So, extensive studies on the prevalence, genetic types, and epidemiology of CTX-M-type ESBLs are needed to refine the infection treatment.

A Computer-Assisted, Real-Time Feedback System for Medical Students as a Tool for Web-Based Learning

황현용 고신대학교(의대) 고신대학교 의과대학 학술지 2016 고신대학교 의과대학 학술지 Vol.31 No.2

Objectives: Medical students sometimes do not receive proper feedback from their instructors. This study evaluated a newly developed automated and personalized real-time feedback system intended to address this issue. Methods: Third- and fourth-year medical students participated in quizzes focusing on 17 learning objectives and a five-scale survey that queried their prior knowledge related to blood transfusions. Immediately after completing the quizzes, the students received automated and personalized, real-time feedback and were instructed to take part in self-directed learning. This activity was followed by a final quiz. After completion of the final quiz, the students responded to the five-scale survey that probed the usefulness of and satisfaction with the automated, personalized, real-time feedback system. Results: Eighty students took part in this study. The third-year group had a higher score for prior knowledge and also on the first quiz (P = 0.008, P = 0.046, respectively). There was no significant difference in final quiz scores between the third- and fourth-year groups (P = 0.633). The scores for usefulness of and satisfaction with the automated, real-time feedback system were 4.45 and 4.34, and 4.55 and 4.40 in the third- and fourth-year students, respectively. Conclusions: The automated, personalized, real-time feedback system provided timely and effective feedback for medical students and was helpful for their self-directed learning.

광패킷 스위칭 시스템용 중재기 설계 및 구현

황현용,양충열,최지연,조성찬,최영우,김해근,홍현하 한국통신학회 2002 한국통신학회 기타 간행물 Vol.2002 No.10

1999년 고신의료원에서 시행한 자가 말초혈액 조혈모세포 이식의 결과 분석

황현용,김미향,김양수,어완규,박재선,정석훈,이천수 대한임상검사정도관리학회 2001 臨床檢査와 精度管理 Vol.23 No.1

Practical Application of Quantitative HiSens Auto Rapid Plasma Reagin Latex Turbidimetric Immunoagglutination for Diagnosing Syphilis; Comparison Analysis between Rapid Plasma Reagin Latex Turbidimetric Immunoagglutination Test and Rapid Plasma Reagin Ca

황현용,김미향 대한감염학회 2009 Infection and Chemotherapy Vol.41 No.3

Background:The purpose of this study was to evaluate validity of quantitative RPR LTIA, HiSens Auto RPR LTIA (HBi Corp., South Korea) and to decide an adequate cutoff value for syphilis screening. Materials and Methods:A total of 549 serums or plasma specimens from patients were tested with RPR LTIA and RPR card tests. Degree of agreement between the two methods was analyzed, and validity of RPR LTIA test was analyzed by receiver operating characteristic (ROC) curves. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and ROC statistics of the RPR LTIA test were analyzed to decide an adequate cutoff value. Results:Agreement analysis showed slight to moderate agreement (k=0.093-0.588, P=0.000). Kappa value had its highest value at the cutoff value of 1.3 and 1.6 (k=0.588, P=0.000). Kappa value at the cutoff value of 1 ranked second (k=0.578. P=0.000). A plot of ROC curve showed a statistically valid result to differentiate between a syphilis test positive group and a syphilis test negative group (AUC=0.92, P=0.000). The cutoff values in RPR LTIA test ranged between 0.65 and 1.15 when both sensitivity and specificity were higher than 80%. Conclusion:HiSens Auto RPR LTIA test showed statistically valid result to differentiate between syphilis test groups. Considering the importance of sensitivity in screening for syphilis and the degree of agreement with RPR card test, the cutoff value of 1 in HiSens Auto RPR LTIA test is thought to be adequate. Background:The purpose of this study was to evaluate validity of quantitative RPR LTIA, HiSens Auto RPR LTIA (HBi Corp., South Korea) and to decide an adequate cutoff value for syphilis screening. Materials and Methods:A total of 549 serums or plasma specimens from patients were tested with RPR LTIA and RPR card tests. Degree of agreement between the two methods was analyzed, and validity of RPR LTIA test was analyzed by receiver operating characteristic (ROC) curves. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and ROC statistics of the RPR LTIA test were analyzed to decide an adequate cutoff value. Results:Agreement analysis showed slight to moderate agreement (k=0.093-0.588, P=0.000). Kappa value had its highest value at the cutoff value of 1.3 and 1.6 (k=0.588, P=0.000). Kappa value at the cutoff value of 1 ranked second (k=0.578. P=0.000). A plot of ROC curve showed a statistically valid result to differentiate between a syphilis test positive group and a syphilis test negative group (AUC=0.92, P=0.000). The cutoff values in RPR LTIA test ranged between 0.65 and 1.15 when both sensitivity and specificity were higher than 80%. Conclusion:HiSens Auto RPR LTIA test showed statistically valid result to differentiate between syphilis test groups. Considering the importance of sensitivity in screening for syphilis and the degree of agreement with RPR card test, the cutoff value of 1 in HiSens Auto RPR LTIA test is thought to be adequate.

급성 림프구성 백혈병 소아에서 골수세포의 세포면역표현형 분석

황현용,김미향,홍유라,박재선 고신대학교의과대학 2006 고신대학교 의과대학 학술지 Vol.21 No.2

Background Immunophenotypic analysis of leukemic cells can be used to define specific subgroups of leukemia with different prognoses and, thereby, indicate appropriate treatment for individual cases. In this study, we analysed the immunophenotype of leukemic cells in a group of children diagnosed as acute lymphoblastic leukemia in order to assess the frequency of the different immunologic subtypes. Methods From October 1992 to January 1999, 18 patients were enrolled in this study. Conventional immunological markers were used, either associated to or specific for B, T, or myelo-monocytic cell populations. Results Among 18 acute lymphoblastic leukemia (ALL), the most predominant immunophenotype was T cell ALL (n=8) followed by early pre-B (n=6), pre-B (n =2) and B cell (n=2). CD10 (CALLA) positive ALL was found in 7 of 17 children, and were not different from CD10 negative ALL in terms of complication and survival. Eight of 12 acute lymphocytic leukemia patients, who were checked for terminal deoxynucleotidyl transferase (Tdt), were Tdt positive, whereas both of two patients with B cell ALL showed least reactivity. Tumor lysis syndrome was developed only in patients with T cell ALL (3/ 8). Conclusion T cell ALL was the most frequent immunophenotype and was occurred predominantly in male sex and older age. Although the number of the patients studied was small, there was no significant difference in survival rates between T cell leukemia and B lineage leukemia. Ongoing studies with large group of patients over longer periods need to be done to explore any difference in biological behavior and prognosis among the subgroups of ALL.

47,XYY 핵형을 나타낸 급성 골수성 백혈병 1예

황현용,김미향,김양수,어완규,정석훈 대한임상병리학회 2000 대한임상병리학회지 Vol.20 No.4

퀴즈의 위력: 무들을 이용한 의학영어 수업 경험

황현용 한국의학교육학회 2009 Korean journal of medical education Vol.21 No.1

Purpose: The purpose of this research is to evaluate whether quizzes using moodle are useful for academic achievement in a medical English class and to introduce moodle to educators based on the author’s teaching experience. Methods: After a final examination in a medical English class, the author surveyed (scale of 1 low to 5 high) the degree of satisfaction of students and the usefulness of quizzes provided on the author’s homepage using moodle. Students had been recommended to solve the quizzes on the homepage voluntarily. The author analyzed statistical differences of the final examination scores between the students who completed the quizzes and those who did not. Results: A total of 59 students completed the survey (collection rate=81.9%). On the question of satisfaction about the medical English class and the question of usefulness of quizzes, scores of mean, maximum, and minimum were 4.29 (SD=0.56), 5, and 3, and 4.03 (SD=0.72), 5, and 2, respectively. Statistically significant differences in the final examination scores were observed between the students who completed quizzes and those who did not. Conclusion: A tool for students’self-directed study is needed for improving academic achievement. In particular, various educational programs and environments provided by moodle are thought to be very useful. The quizzes the author made with moodle were very effective in the aspect of achievement.

ANA 선별 검사가 음성이면 ENA 자가항체 검사는 안해도 되는가? : IIFA에 의한 ANA선별 검사 결과와 LIA에 의한 Ro60과 Ro52 자가항체 검사 결과의 연관성 분석

황현용,김종국 고신대학교의과대학 2007 고신대학교 의과대학 학술지 Vol.22 No.2

Background: Differently from a theory, the test results of anti-extractable nuclear antigen antibody (ENA Ab) are sometimes positive when those of antinuclear antibody are negative in the same patient. We performed the association analysis between the result of ANA and that of R060 and Ro52 ENA Abs which are prevalently identified in the laboratory practice. Methods: From January 2006 to June 2007, a total of 133 patients’ test results of ANA by indirect immunofluorescence assay (IIFA) and 13 ENA Abs by line immunoassay (LIA) were analyzed. The patients were divided into 3 groups depending on the results of Ro antibodies: 1) Ro60 (+)-Ro52 (+), 2) Ro60 (+)-Ro52 (-), 3) Ro60 (-)-Ro52 (+). The associations between the results of IIFA and those of LIA in between the groups were analyzed. The associations between the results of IIFA and those of LIA and the prevalence of ENA Abs were analyzed in the ENA (+) group. The prevalence of ENA Abs in the IIFA (-)-LIA (+) group was analyzed. The distributions of ENA Abs identified in the same patient were analyzed in LIA (+), IIFA (+)-LIA (+), and IIFA (-)-LIA (+) groups. Results: There were no statistical differences between the results of ANA and those of ENA Abs in between the groups, but significant difference was suspected between the Ro60 (+)-Ro52 (+) and the Ro60 (-)-Ro52 (+) groups (p=0.052). The prevalence of Ro60 a d Ro52 were high among 13 ENA Abs identified (18.8% and 24% respectively). Statistically significant association between the results of ANAs and those of Ro60 was observed (p=0.005). The prevalence of Ro52 was highest in the IIFA (-)-LIA (+) group (28.6%). The numbers of ENA Abs identified in the same patient decreased in the IIFA (-)-LIA (+) group. Conclusion: When the autoimmune diseases associated with Ro52 autoantibody are suspected, an ENA profile test should be performed regardless of the ANA results.

Beckman Coulter LH750 혈액분석 장비를 이용한 지연된 검체의 혈액학적 검사 결과 변화 분석

황현용,김미향 고신대학교의과대학 2007 고신대학교 의과대학 학술지 Vol.22 No.1

Background Delayed sample analysis is not a rare case in clinical and laboratory practice, especially when blood samples are transported to distant centralized laboratories. In such a case, there might be changes in hematologic parameters. In this study we intended to evaluate the stability of hematologic parameters in delayed blood samples stored for as long as 24 hours at 4℃. Methods Hematologic parameters were tested twice for 100 same specimens at zero and 24 hours after. For statistical significance, paired t-test, Bland-Altman plots, limit-of-agreement analysis, and linear regression analysis were used. Results Of 31 parameters statistically significant differences were observed in white blood cell (count and percentage), hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin concentration, platelet, plateletcrit, mean platelet volume, platelet distribution width, neutrophiles (count and percentage), eosinophiles (count and percentage), nucleated red blood cell, immature reticulocyte fraction, mean sphered cell volume and high light scatter reticulocytes (count and percentage)(p < 0.05). Bland-Altman plots and limits-of-agreement analysis showed roughly acceptable percent bias except for white blood cell count (%bias, 7.2), MPV (-10.2%), and eosinophil fraction (-25.6). Simple linear regression analysis was performed for the parameters with good correlation showing excellent r^(2) between delayed and original sample test results, which suggested the possibility of presumption of original test results using delayed sample test results. Conclusion Inevitably do we confront a delayed sample causing some changes in hematologic parameters, in such a case additional corrected results need to be reported and also further study have to be done for more rational resolution.