1.Two Cases of Bacteremias Caused by Clostridium ramosum.
Yong Kwan LIM ; Se Min OH ; Oh Joo KWEON ; Mi Kyung LEE
Annals of Clinical Microbiology 2015;18(3):98-101
Clostridium ramosum is Gram-positive anaerobic bacillus and is known as a non-pathogenic enteric bacterium. It is a member of the RIC group, which is a subgroup of Clostridium having atypical characteristics. Rarely, it has been reported as a pathogen of otitis media in young children or the cause of infection in immunosuppressed adults. Here, we report the first two Korean cases of C. ramosum bacteremia in colon cancer and pressure sore cases, respectively.
Adult
;
Bacillus
;
Bacteremia*
;
Child
;
Clostridium*
;
Colonic Neoplasms
;
Humans
;
Immunocompromised Host
;
Otitis Media
;
Pressure Ulcer
2.The Role of Nuclear Factor Kappa B on Lens Epithelial Cells after Ultraviolet B Irradiation.
Do Hyung LEE ; Jung Kweon KIM ; Sae Hoon OH ; Eung Kwon KIM ; Choun Ki JOO
Journal of the Korean Ophthalmological Society 2004;45(3):500-506
PURPOSE: This study was performed to determine the role of nuclear factor kappa B (NF-kappa B) on the lens epithelial cell death after ultraviolet (UV) irradiation. METHODS: Simian virus 40 transfected human lens epithelial cells (HLE B-3 cells) were used in this study. UVB located at 10cm from the bottom was irradiated during 1, 2, 3 and 4 minutes. To measure the cytotoxicity MTT assay was used. Translocation of NF-kappa B was examined by immunocytochemistry with anti NF-kappa B p65 antibody and electrophoretic mobility shift assay (EMSA). To confirm the role of NF-kappa B, the cells were pretreated with sulfasalazine, a specific inhibitor of NF-kappa B, for 30 minutes before irradiation, and cytotoxicity and translocation of NF-kappa B were evaluated. RESULTS: UV irradiation produced a progressive cytotoxic effect in cultured HLE B-3 cells after 1 minute and maximum cytotoxicity was reached after 3 minutes irradiation. When HLE B-3 cells were irradiated with UVB, the translocation of NF-kappa B was observed in immunocytochemistry. These translocations were peaked 6 hours after UV irradiation in EMSA. In HLE B-3 cells pretreated with sulfasalazine, the translocation of NF-kappa B was blocked. The cellular death after UV irradiation was markedly blocked by sulfasalazine. UV irradiation can translocate NF-kappa B and sulfasalazine is a useful blocking agent in this pathway. In addition, sulfasalazine can prevent cellular death after UV irradiation. CONCLUSIONS: These findings suggest that NF-kappa B plays an important role in cellular death after UV irradiation.
Electrophoretic Mobility Shift Assay
;
Epithelial Cells*
;
Humans
;
Immunohistochemistry
;
NF-kappa B*
;
Simian virus 40
;
Sulfasalazine
;
Transcription Factor RelA
3.Discrepancy between Vitamin D Total Immunoassays due to Various Cross-reactivities.
Jun Hyung LEE ; Jee Hye CHOI ; Oh Joo KWEON ; Ae Ja PARK
Journal of Bone Metabolism 2015;22(3):107-112
BACKGROUND: The purpose of this study was to find out the cause of discrepancy between various automated immunoassays for 25-hydroxy-vitamin D (25-[OH]D). METHODS: National Institute of Standards & Technology Standard Reference Material (SRM) 972a is SRM for 25-(OH)D and consists of 4 vials of frozen serum with different concentrations of 25-(OH)D. Each concentration was measured 6 times in 3 different immunoassays: ADVIA Vitamin D Total assay (Siemens Healthcare, Erlangen, Germany), ARCHITECT 25-(OH)D (Abbott Laboratories, Abbott Park, IL, USA), and COBAS Vitamin D Total assay (Roche Diagnostics, Basel, Switzerland). RESULTS: When using the certified reference values of SRM 972a as it is, discarding the cross-reactivity of each immunoassay, for ADVIA, the coefficient of determination (R2) as a score of regression analysis was 0.8995 and maximal difference between measured value and certified reference value was 3.6 ng/mL in level 3. The R2 and maximal differences of ARCHITECT were 0.5377 and 6.9 ng/mL, respectively, in level 4. Those of COBAS were 0.3674 and 22.3 ng/mL, respectively, in level 4. When considering cross-reactivities of each immunoassays to various 25-(OH)D metabolites, the ADVIA had R2 and maximal difference of 0.9254 and 3.3 ng/mL, respectively, in level 3. For ARCHITECT, the R2 and maximal differences were 0.7602 and 5.1 ng/mL, respectively, in level 1. Those of COBAS were 0.9284 and 4.9 ng/mL, respectively, in level 1. CONCLUSIONS: The cause of discrepancies between vitamin D immunoassays was mainly on the difference in cross-reactivities to various vitamin D metabolites. The discrepancies can be considerably decreased by considering cross-reactivities of each immunoassay.
Cross Reactions
;
Delivery of Health Care
;
Immunoassay*
;
Reference Values
;
Vitamin D*
;
Vitamins*
4.Interpretation of Papanicolaou Smear Test and Gram Stain Results for the Diagnosis of Infectious Vaginitis is Affected by Knowledge of Additional Related Test Results.
Bo Hyun KIM ; Jun Hyung LEE ; Oh Joo KWEON ; Nae YU ; Mi Kyung LEE
Laboratory Medicine Online 2014;4(2):105-111
BACKGROUND: Infectious vaginitis is a common gynecologic disease that is primarily caused by three pathogens (Trichomonas vaginalis, Gardnerella vaginalis, and Candida species). The aim of this study was to confirm the effects of other infectious vaginitis-related test results on the interpretation of Gram stain and Papanicolaou (Pap) smear test results for disease diagnosis. METHODS: A total of 300 vaginal samples were collected from women presenting symptoms of vaginitis. The presence of the three previously mentioned pathogens was evaluated using both a Gram stain and Pap smear test, and interpreted twice by 4 different observers. The first interpretation was performed without any information, and a second interpretation was performed with knowledge of results of an Affirm VPIII test that was used to diagnose infectious vaginitis. The results from the two interpretations were compared and the sensitivity and specificity of both tests were evaluated. RESULTS: For the Gram stain samples, the detection rates of G. vaginalis were increased in the second interpretation by 6.2%, while the detection rates of Candida spp. were decreased by 0.3%. For the Pap smear test samples, the detection rates of G. vaginalis were increased in the second interpretation by 7.0%, and the detection rates of Candida spp. were increased by 2.0%. The sensitivity of both tests was increased in the second interpretation by 5.5% to 66.7%. There was no difference in the specificity between the two interpretations. CONCLUSIONS: We demonstrated that there is significant inter-observer variation when using Gram stain and Pap smear test results to diagnose infectious vaginitis. The detection rates and sensitivity of both tests changed when the results from an additional test were incorporated into the interpretation. Additional studies are needed to develop objective criteria and a standardized interpretation system for the evaluation of results from these diagnostic tests.
Candida
;
Diagnosis*
;
Diagnostic Tests, Routine
;
Female
;
Gardnerella vaginalis
;
Genital Diseases, Female
;
Humans
;
Knowledge of Results (Psychology)
;
Observer Variation
;
Papanicolaou Test*
;
Sensitivity and Specificity
;
Vaginitis*
5.Two Cases of Enterobacter hormaechei Infection Misidentified as Cedecea davisae Infection.
Yong Kwan LIM ; Oh Joo KWEON ; Mi Kyung LEE ; Kyoung Un PARK
Laboratory Medicine Online 2015;5(4):223-226
Enterobacteriaceae is a family of gram-negative, rod-shaped bacteria that consists of various species. Among these, members of the genus Cedecea has been reported as relatively rare causative pathogens of human infections. Commercially available automated identification systems that use biochemical reactions are known to accurately identify Enterobacteriaceae species. However, the accurate identification of some organisms with diverse biochemical profiles by these automated identification systems may be problematic. In this study, we report two cases of isolate misidentification, from patients with acute cholecystitis and deep vein thrombosis, as Cedecea davisae with VITEK II system. Both the isolates were correctly identified as Enterobacter hormaechei using gyrB gene sequence analysis. We also performed 16S rRNA sequence analyses and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analyses; however, indeterminate results were obtained from both the assays. Therefore, the sequence analysis of alternative genes, like gyrB, might be useful for accurate identification of species that belong to the family of Enterobacteriaceae.
Bacteria
;
Cholecystitis, Acute
;
Enterobacter*
;
Enterobacteriaceae
;
Humans
;
Mass Spectrometry
;
Sequence Analysis
;
Venous Thrombosis
6.Real-World Accuracy of a SARS-CoV-2 Rapid Diagnostic Tests in the Republic of Korea
Oh Joo KWEON ; Hye Ryoun KIM ; Mi-Kyung LEE ; Yong Kwan LIM
Journal of Korean Medical Science 2022;37(43):e310-
Antigen rapid diagnostic tests (RDTs) became the most important tool for the diagnosis of the coronavirus disease 2019 (COVID-19), however there have been very few evaluations of the accuracy of the RDTs in actual use. In this study, we investigated the performance accuracy of the RDT, the STANDARD Q COVID-19 Ag (STANDARD Q), in the Republic of Korea. We collected a total of 5,792 results that underwent both RDT and reverse transcription polymerase chain reaction simultaneously, and overall sensitivity and specificity of the STANDARD Q were 57.6% and 99.9%, respectively. With binomial logistic regression analysis, we estimated that about half of the COVID-19 patients with a cycle threshold value of 25 for E and RdRP were RDT-negative. These results suggest that the clinical sensitivity of RDTs against severe acute respiratory syndrome coronavirus 2 is considerably low in a real-world setting, and we recommend that limitations of RDTs should be considered when setting up COVID-19 test strategies.
7.Effectiveness of Platelet Function Analyzer-100 for Laboratory Detection of Anti-Platelet Drug-Induced Platelet Dysfunction.
Oh Joo KWEON ; Yong Kwan LIM ; Bohyun KIM ; Mi Kyung LEE ; Hye Ryoun KIM
Annals of Laboratory Medicine 2019;39(1):23-30
BACKGROUND: High on-treatment platelet reactivity (HTPR) is the phenomenon wherein patients exhibit normal platelet activity in laboratory testing despite adequate adherence to anti-platelet treatment. We investigated the detection rates of Platelet Function Analyzer (PFA)-100 (Dade Behring AG, Düdingen, Switzerland) for drug-induced platelet dysfunction and analyzed potential contributors to HTPR with practical PFA-100 data over six years. METHODS: We used data from 6,957 patients who underwent PFA-100 testing after receiving aspirin, clopidogrel, or non-steroidal anti-inflammatory drugs (NSAIDs). Of these, 6,163 patients were tested with only the collagen/epinephrine cartridge (Col/EPI) of PFA-100; 794 were tested with both Col/EPI and the collagen/ADP cartridge (Col/ADP). We calculated PFA-100 closure time (CT) for each drug and compared the clinical and laboratory characteristics of the patients with prolonged CTs and normal CTs (i.e., HTPR). RESULTS: In Col/EPI, 73.2% (365/499), 72.6% (390/537), and 55.3% (3,442/6,228) patients showed prolonged CTs for aspirin, clopidogrel, and NSAIDs, respectively. In Col/ADP, prolonged CTs were observed in 37.4% (34/91), 43.2% (35/81), and 29.6% (200/676) of patients receiving aspirin, clopidogrel, and NSAIDs, respectively. Of the patients tested with both cartridges, 88.9% (48/54), 95.3% (41/43), and 89.0% (577/648) of the patients receiving aspirin, clopidogrel, and NSAIDs had prolonged CTs, and 10.0% (79/794) showed normal CTs regardless of drugs. For clopidogrel users (both cartridges), there were more patients with malignancies in the normal CT than prolonged CT group. CONCLUSIONS: PFA-100 is not sufficiently effective for laboratory screening of drug-induced platelet dysfunction. Malignancy may contribute to clopidogrel-related HTPR in PFA-100.
Anti-Inflammatory Agents, Non-Steroidal
;
Aspirin
;
Blood Platelets*
;
Humans
;
Mass Screening
8.Establishment of Reference Intervals of Cytokeratin 19 Fragment Antigen 21-1 in Korean Adults
Sumi YOON ; Yong Kwan LIM ; Hye Ryoun KIM ; Mi-Kyung LEE ; Oh Joo KWEON
Annals of Laboratory Medicine 2023;43(1):82-85
Cytokeratin 19 fragment antigen 21-1 (CYFRA 21-1) is useful for predicting and monitoring non-small cell lung cancer prognosis. We established reference intervals (RIs) of CYFRA 21-1 in Korean adults, including those older than 60 years. Data of 4,098 apparently healthy subjects (age range, 20–87 years) were analyzed after excluding those with a history of malignancy, high tumor marker concentrations (except CYFRA 21-1), and/or abnormal findings on a chest computed tomography scan through medical chart review. After removing two outliers, RIs of CYFRA 21-1 were determined using data of 4,096 subjects based on the non-parametric method (2.5th and 97.5th percentiles) according to CLSI guidelines EP28-A3c. The subjects were divided into two and four groups according to sex and age (20–40, 41–50, 51–60, and >60 years), respectively, and the median CYFRA 21-1 concentration was compared between the groups. The RI of CYFRA 21-1 was 0.66–3.84 ng/mL, applicable to both men and women. Regardless of sex, the CYFRA 21-1 concentration increased with age, suggesting that age-dependent RIs of CYFRA 21-1 should be applied. Rather than using a single RI provided by the manufacturer, the RI of CYFRA 21-1 should be continually verified and established in each clinical laboratory.
10.Positivity of Rapid Antigen Testing for SARS-CoV-2 With Serial Followed-up Nasopharyngeal Swabs in Hospitalized Patients due to COVID-19
Oh Joo KWEON ; Joo Hee LEE ; Yang-Seon CHOI ; Boo-Seop KIM ; Yong Kwan LIM ; Mi-Kyung LEE ; Joung Ha PARK ; Ji Young PARK ; Seong Hwan KIM
Journal of Korean Medical Science 2022;37(21):e168-
Despite the accuracy of nucleic acid amplification tests (NAATs), rapid antigen tests (RATs) for severe acute respiratory syndrome coronavirus-2 are widely used as point-of-care tests. A total of 282 pairs of reverse transcription-polymerase chain reaction and Standard Q COVID-19 Ag tests were serially conducted for 68 patients every 3–4 days until their discharge. Through a field evaluation of RATs using direct nasopharyngeal swabs, the sensitivities were 84.6% and 87.3% for E and RNA-dependent RNA polymerase (RdRp) genes, respectively, for specimens with cycle thresholds (Cts) < 25. The Ct values of E and RdRp genes for 95% detection rates by RATs were 16.9 and 18.1, respectively. The sensitivity of RAT was 48.4% after the onset of symptoms, which was not sufficient. RAT positivity gradually decreased with increased time after symptom onset and had continuously lower sensitivity than NAATs.