Performance Evaluation of Chemiluminescent Immunoassay for Erythropoietin and Establishment of Reference Interval in Korean Population / 임상검사와정도관리

BACKGROUND: The measurement of serum erythropoietin (EPO) is useful for the differential diagnosis of polycythemia and anemia and for treatment monitoring of recombinant human EPO. Radioimmunoassay (RIA) has been used in several clinical laboratories of Korea, and recently a few manufacturers developed fully automated chemiluminescence immunoassay (CLIA). We evaluated performance of Access EPO assay (Beckman Coulter, USA) using CLIA and established reference interval for Korean adults with this assay. METHODS: The precision, linearity, limit of detection, percent carryover, comparison of Access EPO CLIA and EPO-Trac RIA (DiaSorin Ltd, UK), and establishment of reference interval were determined according to the Clinical and Laboratory Standards Institute guidelines. The quality control materials were used in the determination of precision, limit of detection, and carryover. For the reference interval, serum specimens obtained from a total of 120 healthy adults were used. RESULTS: The linearity was good (R2=0.998) from 0.5 IU/L to 732.3 IU/L and within-run and total imprecision were 2.1-4.1% and 2.6-4.1%, respectively. The lower limit of detection was 0.259 IU/L and percent carryover was 0.18%. A comparison analysis with RIA assay showed good correlation, with a correlation coefficient (R) of 0.88. The reference interval was from 2.5 IU/L to 30.8 IU/L with nonparametric method. CONCLUSIONS: The Access EPO assay provided suitable performance for linearity, precision, and detection limits for clinical laboratory. As this assay does not need radioactive isotopes and afforded a short turnaround time (<1 hr), it is expected to be clinically useful especially for the outpatients.

Prevalence of Human Papillomavirus Genotypes in Routine Pap Smear of 2,562 Korean Women Determined by PCR-DNA Sequencing

The infections by human papillomaviruses (HPVs) are clearly associated with the subsequent development of cervical cancer. In this study, HPV genotype distribution and prevalence were detected in Korean women from January to December 2008 using PCR-DNA sequencing. A total of 2,562 cervical samples from Korean women having routine Pap smear cytology screening were used. HPV DNA was extracted from cervical swab samples and amplified by PCR in L1 region of HPV. HPV DNA was detected in 23.2% and 65.5% from the groups of normal and abnormal Pap cytology, respectively. The prevalence of high-risk types of HPV had the highest frequency in the <30 year-olds' group (50.6%). The prevalence of HPV in normal, ASCUS, LSIL and HSIL groups was 23.2%, 58.1%, 96.3% and 97.0%, respectively. Moreover, the frequencies of the high-risk types of HPV were 16.2% in the normal Pap cytology, 44.7% in the ASCUS, 76.1% in the LSIL and 94.1% in the HSIL groups. The prevalence of the high-risk types of HPV increased in proportion to the severity of the cytological classification. In the HSIL group, HPV type 16 was the most frequently found at 32.4%, followed by types 58, 53 and 33 at 17.6%, 14.7% and 11.8%, respectively. HPV type 82 was found in 5.6% of the HSIL group and was not detected in the normal Pap cytology group. The frequency of high-risk type of HPV 82 is firstly reported in Korean women. This finding could be an informative basis for the development of future HPV vaccination strategies in Korean women.

Genetic Analysis of Hepatitis A Virus Isolated from Korea

Hepatitis A virus (HAV) is one of the most important causes of acute infectious hepatitis. The aim of this study was to determine the genotypes of HAV that have been circulating in Koreans. A total of 76 sera referred to our institute for HAV genotyping from 11 Korean provinces were used for this study. Those samples were diagnosed by positive of IgM anti-HAV. HAV RNA was extracted from 150 microliter of serum, and reverse transcription PCR-sequencing was used to detect and characterize HAV RNA. Primer pairs from the VP1/2A region of the HAV were used for amplification and sequencing. HAV RNA was found in 64.5% (n = 49) of the 76 patient sera with acute hepatitis A. Forty-seven strains were genotype IIIA in a total of 49 isolated strains (95.9%, 47/49); only two strains belonged to genotype IA (4.1%, 2/49). Thirty eight genotype IIIA isolates were 100% identical to consensus amino acid sequences of the reference strain AJ299467. The amino acid change of L772F was found in two IIIA strains; other IIIA isolates showed one amino acid change. Amino acid of genotype IA was compared to reference strain L20541. K801R was found in 1 strain and Q810S in both strains. The amino acid change of K801R was the first report in Koreans. Until recently HAV genotype IA has been reported as a major circulating HAV genotype in Koreans. In the present study, the predominant HAV strain in Koreans seemed to be HAV genotype IIIA.

A Case of Bacteremia Caused by Arthrobacter woluwensis / 대한임상미생물학회지

Arthrobacter spp. are coryneform bacteria known as a soil flora and also part of normal flora of human. Since coryneform bacteria are often reported to be a cause of life-threatening diseases, and especially the human infections of Arthrobacter spp. are reported recently, it is important to identify them to the genus and species levels by additional studies including molecular tests. We report a case of bacteremia caused by Arthrobacter woluwensis, which was misidentified initially as Leifsonia aquatica by commercial kits and conventional tests, but correctly identified by 16S rRNA sequencing.

Investigation of Hemostatic Changes in Patients with Sepsis / 대한진단검사의학회지

BACKGROUND: It is known that severe infection and inflammation lead to hemostatic abnormalities. Recently, much attention is focused on the mechanisms of infection or inflammation and on how it plays a central role in effecting the coagulation system. Disseminated intravascular coagulation in particular, is a common phenomenon in patients with sepsis, but the clinical implications of this condition are not clear. Therefore we attempted to evaluate the changes of the coagulation system in patients with sepsis and studied the factors that lead to such changes. METHODS: One hundred one patients diagnosed with sepsis were enrolled in this study. The patients were clinically evaluated for underlying disease and data for inflammatory status and coagulative changes were evaluated retrospectively. RESULTS: The WBC count increased in 76% and decreased in 6% of sepsis patients in comparison to the reference interval. The platelet count decreased in 65.3%. Changes in coagulative tests such as prothrombin time, activated partial thromboplastin time, antithrombin III, and D-dimer were observed in 70.4%, 52.7%, 87.2% and 100% of the patients, respectively. Correlation between ESR and fibrinogen was the highest in relation to the other coagulation factors. CRP also showed the highest correlation with fibrinogen in contrast to the other coagulation factors. CONCLUSIONS: This study confirmed the clear activation of coagulation in patients with sepsis. Of the evaluated factors involved in coagulation and fibrinolysis, fibrinogen showed the highest correlation to indices representing the inflammatory state. However further studies on the anticoagulant pathway are necessary in elucidating this matter.

A Case of Bacteremia Caused by Leuconostoc lactis Identified by 16S rRNA Sequencing / 대한임상미생물학회지

Leuconostoc spp. used to be considered nonpathogens to human, but human infections have been reported including bacteremia in compromized patients. Leuconostoc spp. may be misidentified as lactobacilli, streptococci, pediococci and enterococci due to atypical biochemical tests. Leuconostoc spp. are intrinsically resistant to vancomycin. We report a case of bacteremia caused by Leuconostoc lactis identified by 16S rRNA sequencing; the isolate was not identified by commercial kits.

An Analysis of Antituberculosis Drug Susceptibility Test Results in Kyung Hee Medical Center During Recent Four years / 대한임상미생물학회지

BACKGROUND: Tuberculosis is still one of the most seriously threatening infections in Korea, because of multidrug resistant tuberculosis. Results of antituberculosis drug susceptibility test can provide clinicians very important informations for selection of proper regimens for treatment. METHODS: In this study the results of antituberculosis drug susceptibility test of 298 cases at Kyunghee Medical Center from 2000 to 2003 were retrospectively analysed to evaluate the trend of antituberculosis drug susceptibility. The procedure of drug susceptibility test was based on the absolute concentration method using Lowenstein-Jensen solid media. RESULTS: The resistance rate of Mycobacterium tuberculosis to one or more drugs was increased from 29.3% in 2000 to 48.2% in 2003, and the rates of multiple resistance to two or more drugs increased from 13.3% in 2000 to 20.5% in 2003. The increase in resistance rate to individual drug during study period were 20.0% to 24.1% in isoniazid, 9.3% to 19.3% in rifampicin, 5.3% to 15.7% in ethambutol, 4.0% to 10.8% in para-aminosalicylic acid, 2.7% to 6.0% in kanamycin, 1.3% to 7.2% in ethionamide, 1.3% to 6.0% in capreomycin, 1.3% to 7.2% in prothionamide, 0.0% to 12.1% in ofloxacin, 6.7%to 3.6% in streptomycin, 6.7% to 7.2% in cycloserine, 10.7% to 8.4% in pyrazinamide, respectively. CONCLUSIONS: The resistance rate of M. tuberculosis has been increased with years and multidrug resistant M. tuberculosis was commonly encountered in the specimens from the patients visited Kyunghee Medical center.

Application of the Revised Case Matrix Format to Tutorial in Pathology Teaching: An Interim Approach toward Problem-Based Learning under Traditional Curricular Structure

This paper describes a student-centered case study program concerning the tumor pathology course for first year students in medical school under the traditional curricular structure. A traditional, discipline-oriented, lecture-laboratory approach was partly modified by introducing a tutuorial session using a modified case matrix format during the laboratory hours without altering the general scheme of the existing system. Small group tutorial sessions were set with the development of learning objectives emphasizing clinicopathologic reasoning and early exposure to future practical presentation which was followed by the large class session; each tutorial was supplied with a short clinical history, gross kodachrome slides, and microslides. The session for problem identification was replaced by proving a series of instructor-designed questions for both pathology and interdisciplinary correlation during which pedagogical implication was stressed the most. Student's active participation, development of self learning skill and vigorous teaching-learning process among students, and motivation/relevance for forthcoming pathology study were among the benefits conferred by this modification. We conclude that this approach is an interim step to meet the advantages of problem-based learning even in a traditional curricular structure.

Application of the Revised Case Matrix Format to Tutorial in Pathology Teaching: An Interim Approach toward Problem-Based Learning under Traditional Curricular Structure

This paper describes a student-centered case study program concerning the tumor pathology course for first year students in medical school under the traditional curricular structure. A traditional, discipline-oriented, lecture-laboratory approach was partly modified by introducing a tutuorial session using a modified case matrix format during the laboratory hours without altering the general scheme of the existing system. Small group tutorial sessions were set with the development of learning objectives emphasizing clinicopathologic reasoning and early exposure to future practical presentation which was followed by the large class session; each tutorial was supplied with a short clinical history, gross kodachrome slides, and microslides. The session for problem identification was replaced by proving a series of instructor-designed questions for both pathology and interdisciplinary correlation during which pedagogical implication was stressed the most. Student's active participation, development of self learning skill and vigorous teaching-learning process among students, and motivation/relevance for forthcoming pathology study were among the benefits conferred by this modification. We conclude that this approach is an interim step to meet the advantages of problem-based learning even in a traditional curricular structure.