Validation of QF-PCR for Rapid Prenatal Diagnosis of Common Chromosomal Aneuploidies in Korea

PURPOSE: Quantitative fluorescent polymerase chain reaction (QF-PCR) allows for the rapid prenatal diagnosis of common aneuploidies. The main advantages of this assay are its low cost, speed, and automation, allowing for large-scale application. However, despite these advantages, it is not a routine method for prenatal aneuploidy screening in Korea. Our objective in the present study was to validate the performance of QF-PCR using short tandem repeat (STR) markers in a Korean population as a means for rapid prenatal diagnosis. MATERIALS AND METHODS: A QF-PCR assay using an Elucigene kit (Gen-Probe, Abingdon, UK), containing 20 STR markers located on chromosomes 13, 18, 21, X and Y, was performed on 847 amniotic fluid (AF) samples for prenatal aneuploidy screening referred for prenatal aneuploidy screening from 2007 to 2009. The results were then compared to those obtained using conventional cytogenetic analysis. To evaluate the informativity of STR markers, the heterozygosity index of each marker was determined in all the samples. RESULTS: Three autosomes (13, 18, and 21) and X and Y chromosome aneuploidies were detected in 19 cases (2.2%, 19/847) after QF-PCR analysis of the 847 AF samples. Their results are identical to those of conventional cytogenetic analysis, with 100% positive predictive value. However, after cytogenetic analysis, 7 cases (0.8%, 7/847) were found to have 5 balanced and 2 unbalanced chromosomal abnormalities that were not detected by QF-PCR. The STR markers had a slightly low heterozygosity index (average: 0.76) compared to those reported in Caucasians (average: 0.80). Submicroscopic duplication of D13S634 marker, which might be a unique finding in Koreans, was detected in 1.4% (12/847) of the samples in the present study. CONCLUSION: A QF-PCR assay for prenatal aneuploidy screening was validated in our institution and proved to be efficient and reliable. However, we suggest that each laboratory must perform an independent validation test for each STR marker in order to develop interpretation guidelines of the results and must integrate QF-PCR into the routine cytogenetic laboratory workflow.

An Epidemiological Analysis of Hepatitis A Virus Serologic Markers during the Recent Four Years in Korea / 대한진단검사의학회지

BACKGROUND: To establish effective preventive measures for hepatitis A virus (HAV) infection, a nationwide epidemiologic study on seroprevalence of anti-HAV and the disease prevalence is needed. The aim of this study was to analyze the recent sero-epidemiological changes of hepatitis A markers in Korea. METHODS: The results of 11,068 anti-HAV total and 32,360 anti-HAV IgM tests by electro-chemiluminescence immunoassay (ECLIA) that had been requested in recent four years (2005-2008) to a reference medical laboratory from 1,699 institutions nationwide were retrospectively analyzed according to the distribution of year, sex, and age groups. RESULTS: The overall positive rate of anti-HAV total was 62.8%. The overall positive rate of anti-HAV IgM was 11.0%, showing a significantly increasing trend by year: 7.7%, 10.9%, 8.9%, and 14.3% in 2005, 2006, 2007, and 2008, respectively (P or =21 yr. Conclusion: In accordance with a decreasing sero-positivity of anti-HAV total, the prevalence of acute hepatitis A virus infection has been considerably increased during the recent four years in the age groups of > or =21 yr. The results of this study could be used effectively as a basic data for establishing effective preventive measures for hepatitis A including vaccination in these susceptible age groups.

Distribution of Genes Encoding Aminoglycoside Modifying Enzymes and Type Staphylococcal Chromosomal Cassette mec in Methicillin-resistant Staphylococcus aureus from Non-tertiary Hospitals

BACKGROUND: Many genes encoding aminoglycoside modifying enzymes (AMEs) on transposon or plasmid were transferred from one strain to another strain and inserted into a staphylococcal chromosomal cassette mec (SCCmec). There are very diverse subtypes in SCCmec type to the insertion of resistant genes. Therefore, we researched the resistance rates of antibiotics and distribution of AME genes according to SCCmec type in MRSA strains. MATERIALS AND METHODS: We isolated 640 Staphylococcus aureus from non-tertiary hospitals in 2004, detected mecA, aac(6')-aph(2"), aph(3')-IIIa, and ant(4')-Ia using the multiplex PCR method, tested antibacterial susceptibility disk diffusion and minimal inhibitory concentration, and determined SCCmec type. RESULTS: Of 640 S. aureus isolates, MRSA rate was 39.7% and all MRSA isolates carried mecA gene. Among 214 MRSA selected, aminoglycoside-resistant rates were 98.1% in kanamycin and tobramycin, 68.7% in gentamicin, 30.8% in amikacin, and 2.8% in netilmicin. The detection rates for aac(6')-aph(2"), aph(3')-IIIa, and ant(4')-Ia were 77.1%, 13.1%, and 53.3%, respectively. Also, SCCmec type was 50.9% in SCCmec type II, 16.4% in type III, and 32.7% in type IV. The genes encoding AMEs were distributed aac(6')-aph(2") (49.5%) and aac(6')-aph(2")/ant(4')-Ia (36.7%) in SCCmec type II, aph(3')-IIIa/aac(6')-aph(2") (60%) and aac(6')-aph(2") (31.4%) in type III, and aac(6')-aph(2")/ant(4')-Ia (41.4%) and ant(4')-Ia (50%) in type IV. CONCLUSION: 39.7% of S. aureus isolated from non-tertiary hospitals was resistant to methicillin. More than 90% of MRSA isolates were detected aac(6')-aph(2") in SCCmec type II and III, and ant(4')-Ia in type IV. With these results, the genes encoding AMEs may be closed related to SCCmec type.

Distribution of Genes Encoding Aminoglycoside Modifying Enzymes and Type Staphylococcal Chromosomal Cassette mec in Methicillin-resistant Staphylococcus aureus from Non-tertiary Hospitals

BACKGROUND: Many genes encoding aminoglycoside modifying enzymes (AMEs) on transposon or plasmid were transferred from one strain to another strain and inserted into a staphylococcal chromosomal cassette mec (SCCmec). There are very diverse subtypes in SCCmec type to the insertion of resistant genes. Therefore, we researched the resistance rates of antibiotics and distribution of AME genes according to SCCmec type in MRSA strains. MATERIALS AND METHODS: We isolated 640 Staphylococcus aureus from non-tertiary hospitals in 2004, detected mecA, aac(6')-aph(2"), aph(3')-IIIa, and ant(4')-Ia using the multiplex PCR method, tested antibacterial susceptibility disk diffusion and minimal inhibitory concentration, and determined SCCmec type. RESULTS: Of 640 S. aureus isolates, MRSA rate was 39.7% and all MRSA isolates carried mecA gene. Among 214 MRSA selected, aminoglycoside-resistant rates were 98.1% in kanamycin and tobramycin, 68.7% in gentamicin, 30.8% in amikacin, and 2.8% in netilmicin. The detection rates for aac(6')-aph(2"), aph(3')-IIIa, and ant(4')-Ia were 77.1%, 13.1%, and 53.3%, respectively. Also, SCCmec type was 50.9% in SCCmec type II, 16.4% in type III, and 32.7% in type IV. The genes encoding AMEs were distributed aac(6')-aph(2") (49.5%) and aac(6')-aph(2")/ant(4')-Ia (36.7%) in SCCmec type II, aph(3')-IIIa/aac(6')-aph(2") (60%) and aac(6')-aph(2") (31.4%) in type III, and aac(6')-aph(2")/ant(4')-Ia (41.4%) and ant(4')-Ia (50%) in type IV. CONCLUSION: 39.7% of S. aureus isolated from non-tertiary hospitals was resistant to methicillin. More than 90% of MRSA isolates were detected aac(6')-aph(2") in SCCmec type II and III, and ant(4')-Ia in type IV. With these results, the genes encoding AMEs may be closed related to SCCmec type.

Clinical and Cytogenetic Findings on 31,615 Mid-trimester Amniocenteses / 대한진단검사의학회지

BACKGROUND: Since amniocentesis made prenatal diagnosis feasible in 1967, the method has become a popular tool in obstetric practices. In Korea, the demand for genetic counseling and prenatal tests has increased markedly because the number and proportion of pregnancies in women aged 35 yr and older have increased over a 20-yr period. Here we report clinical and cytogenetic findings on 31,615 mid-trimester amniocenteses. METHODS: To investigate the changes in the annual number of amniocentesis, distribution of indications and age, and cytogenetic findings and abnormality rate according to indications, this study retrospectively analyzed 31,615 cases of mid-trimester amniocentesis performed at Seoul Clinical Laboratories, an independent medical laboratory center, during the past 13 yr (1994-2007). RESULTS: The annual number of amniocenteses has increased substantially since 1994. Among the 31,615 amniocentesis cases, the maternal age between 30 and 34 yr was the most common age group (35.4%). Among clinical indications, abnormal maternal serum screening results have been the most common indication for amniocentesis since 1994. Chromosomal abnormalities were detected in 973 cases (3.1%). Down syndrome was the most common abnormality found (36.9%, 359/973). In sex chromosomal abnormalities, 53 cases of Turner syndromes, 32 cases of Klinefelter syndromes, 20 cases of triple X syndromes, and 15 cases of 47,XYY were diagnosed. Of structural rearrangements, reciprocal translocations between two autosomes were the most common (15.5%, 151/973). Abnormal ltrasonographic findings showed the highest positive predictive value (5.9%) among the clinical indications. CONCLUSIONS: The present study could be used for the establishment of a database for genetic counseling. The discovery of an abnormality provides the option of termination or continuation in the pregnancy, a more suitable obstetric management in Korea.

Antibiotic Resistance Patterns of Staphylococcus aureus Isolated from the Patients Admitted to Non-tertiary Hospitals / 감염

BACKGROUND: About more than 70% of Staphylococcus aureus isolates in tertiary-care hospitals are known to be resistant to methicillin in Korea. But the prevalence of methicillin-resistant S. aureus (MRSA) in the community and non-tertiary hospitals has not been known yet. The aim of this study was to determine the prevalence of resistance among S. aureus isolates in non-tertiary hospitals. METHODS: The isolates were collected at one laboratory center from August 1998 to May 1999. Antimicrobial susceptibility tests against 11 antibiotics were performed by disk diffusion method. Minimum inhibitory concentrations (MIC) for oxacillin and vancomycin were determined by microbroth dilution method. The mecA gene was detected by polymerase chain reaction. The medical facilities which sent specimen to the laboratory were classified into 3 groups; clinic, hospital and general hospital. RESULTS: Of total 469 S. aureus isolates, 296 (63.1%) were from pus, 47 (10.0%) from sputum, 23 (5.0%) from urine, and 22 (4.6%) from blood. Overall prevalence of MRSA in non-tertiary hospital was 43.5% (204/469). Among 3 hospital groups, MRSA in general hospitals (55%) was significantly more prevalent than in hospitals (40%) or clinics (37%). MICs of oxacillin against MRSA isolated from pus and blood ranged from 8 to > or =256 microgram/mL, but 74% (83 isolates) of them was > or =256 microgram/mL. MICs of vancomycin were distributed from 1 to 2 microgram/mL, irrespective of methicillin resistance or hospital groups. The mecA gene was detected in all of methicillin-resistant isolates with MICs of < or =128 microgram/mL. CONCLUSION: In non-tertiary hospitals, 43% of S. aureus isolates were methicillin resistant. This result showed that MRSA in non-tertary hospitals was less prevalent than in tertiary hospitals.

Quantitative Analysis Of Random Chromosomal Aberrations In PHA-Stimulated Blood and Bone Marrow / 대한임상병리학회지

BACKGROUND: Chromosomal aberration observed only in a few metaphases may cause the cytogeneticists to have difficulties in making a decision whether it is due to in vivo mosaicism/multiple clones or due to in vitro artifact. This is especially important when the chromosome of concern has been associated with a classical chromosome syndrome, malignancy or its evolution. Therefore, we aimed to establish a range for random chromosomal aberrations among cells from PHA-stimulated blood(PB) and bone marrow(BM) cultures. METHODS: Among the cells from 449 PB and 472 BM specimens referred for chromosome studies from 1997 to 1998, we analyzed the frequency of random aneuploidy, structural abnormalities, and breaks/gaps. RESULTS: The number of cells analyzed was 5,904/4,488(1997/1998) in PB and 4,211/4,124(1997/1998) in BM. The frequency of metaphases with random chromosomal aberrations of BM(32.10%) was much higher than that of PB(5.90%). The most frequent aberration was chromsome loss. Autosome losses were inversely correlated with autosome size(correlation coefficient = -0.83 and -0.72, p<0.01), smaller chromosomes being lost more frequently while autosome breaks/gaps were correlated with autosome size(correlation coefficient = 0.69 and 0.85, p<0.01), in PB and BM. Comparing the data from 1998 to the data from 1997, the frequency of chromosome losses(<0.5% in PB, <2.25% in BM), gains(<0.1% in PB and BM), breaks/gaps(<0.1% in PB, <0.25% in BM), and structural aberrations(

A Case of Bone Marrow Necrosis Preceeding Acute Monoblastic Leukemia / 대한임상병리학회지

Bone marrow necrosis is rarely diagnosed during life but is more often seen at autopsy by accident. The prognosis of patients with bone marrow necrosis secondary to neoplastic disease is extremely poor. We experienced a 59-year-old man with acute monoblastic leukemia who developed bone marrow necrosis preceding leukemia. He's main complaint was continuous lower back pain. First hematologic examination showed anemia with leukopenia and extensive bone marrow necrosis. After suffering from sepsis and only supportive management, he spontaneously recovered from pancytopenia and achieved hypercellular marrow with trilineage hematopoiesis. After 6 months, he was diagnosed as acute monoblastic leukemia (FAB, AML, M5a) from the sudden appearence of leukemic blasts on peripheral blood smears. After induction chemotherapy, complete remission was achieved. Our experience suggests that bone marrow necrosis is not uncommonly associated with hematologic malignancy and occult cancer. When bone marrow necrosis is found, we should do close follow-up to find out underlying hidden malignancy.

CyCD3+MPO- Biphenotypic Leukemia With Unusual Presentation: A Case Report / 대한혈액학회지

No abstract available.

Application of Phadiatop Test for Screening of Atopy: Based on the CAP Specific IgE Level in Korean Asthmatics / 대한임상병리학회지

BACKGROUND: Phadiatop test which was developed for screening of atopy in eastern asia area, has not been sufficiently evaluated in Korea. In our previous study, the clinical usefulness of Phadiatop test for screening of atopy was evaluated on atopics and non-atopics defined by the results of skin prick tests with 10 inhalant allergens in Korea. In this study, we evaluated the usefulness of Phadiatop test for screening of atopy based on the level of CAP specific IgE in Korean asthmatics. METHODS: On 136 Korean asthmatics, the level of CAP specific IgE to 10 important inhalant allergens and the level of Phadiatop specific IgE to mixture of 8 important inhalant allergens in Korea were measured. Atopics and non-atopics were defined by the results of CAP specific IgE and the sensitivity, specificity, predictive value of a positive and negative result, and concordance rate of Phadiatop test were estimated. RESULTS: The sensitivity, specificity, predictive values of a positive and negative result, and concordance rate of Phadiatop test were 90.5%, 95.0%, 99.1%, 63.3%, and 91.2%, respectively. CONCLUSIONS: Phadiatop test was very sensitive, rapid and convenient, and corresponded well to the results of CAP specific IgE. We concluded that Phadiatop test is very useful as a screening tool of atopy in Korea.

Cytogenetic Aberrations in Patients with Growth Retardation / 대한임상병리학회지

BACKGROUND: Growth retardation (GR) has literally hundreds of causes that have differences in prognoses, complications, and responses to treatments. Especially, growth retarded patients resulting from chromosomal disorders should be genetically counseled. To focus the cytogeneticist's attention on specific chromosomal regions, it is important to understand cytogenetic aberrations associated with GR prior to chromosomal analysis. So, we attempted to figure out the cytogenetic findings of patients with GR and support the effective application of cytogenetic studies, accurate diagnosis and genetic counseling. METHODS: Of 203 cases referred for GR, the positive rate and pattern of chromosomal aberrations were retrospectively analyzed with review of associated clinical features. Cytogenetic studies were performd by high resolution banding technique after peripheral T lymphocyte culture and, if necessary, Ag-NOR stain, C-banding and fluorescence in situ hybridization. RESULTS: Forty two (20.7%) patients had abnormal karyotypes. Thirty one (15.2%) patients had well-recognized chromosomal syndromes including Turner, Cri-du-chat, Edward, 13q- and 18p-/ 18q- syndromes. In addition to those, the sporadic chromosomal aberrations of 11 cases were partial monosomy of 11q23, partial trisomy of 1q32, 4p, 9p, and 14q, and ring chromosome 4 and 18, etc. which were not literally established in view of the correlation with phenotype. CONCLUSIONS: The various results of definite or debating chromosomal disorders associated with GR could be used as the data for diagnosis, management, prognosis, and genetic counseling in growth retarded patients. Furthermore, these may provide the background for prospective study to define the new chromosomal disorders.

Two Cases of Congenital Factor VII Deficiency with Family Study / 대한혈액학회지

Congenital factor VII deficiency is a rare coagulation disorder transmitted in autosomal recessive pattern and is characterized by prolonged prothrombin time with normal activated partial thromboplastin time. It is confirmed by specific factor VII assay. Heterozygotes are generally asymptomatic and homozygotes may present variety of bleeding symptom. But heterozygotes are not always asymptomatic and that patients should receive replacement of factor VII for their operation or abnormal bleeding. We experienced 2 cases of congenital factor VII deficiency diagnosed by prolonged prothrombin time and factor VII assay in routine preoperative evaluation. One was a 27-year-old female who seemed to be an asymptomatic heterozygote underwent orthopedic surgical procedure successfully without abnormal bleeding after receiving fresh frozen plasma. Another was a 18-year-old male who also seemed to be a heterozygote including his family had bleeding symptom such as epistaxis.

Peripheral T Cell Lymphoma Associated with Hemophagocytic Histiocytosis Mimicking Malignant Histiocytosis / 대한임상병리학회지

BACKGROUND: Peripheral T cell lymphoma (PTCL), a prevalent form of non Hodgkin lymphomas in East Asia, can manifest fever, hepatomegaly, lymphadenopathy, pancytopenia and hemophagocytic histiocytosis (HPH). Similar clinicopathologic findings are also frequently encountered in reactive hemophagocytic syndrome (HPS) and malignant histiocytosis (MH) , thus diagnoses could be confused among them. With recent advancement of immunohistochemlal techniques, diagnostic accuracies have been improved and most cases of MH could have been reclassified as PTCL. In this study, we intended to delineate the lineage of atypical malignant cells in bone marrow of subjects which were previously diagnosed as MH or HPS with immunohlstochemical analysis and characterize clinlcophathologic findings of PTCL associated with HPH in the bone marrow. METHODS: Five cases dignosed as HPS, 3 as MH, 3 as presumed MH, and 7 as PTCL on bone marrow examination were enrolled in this study. We performed immunohistochemical stain for CD45, CD3, CD43, CD2O and CD68, then revised the diagnoses and summarized the clinical and morphologic features of PTCL associated with HPH. RESULTS: Eleven out of 18 cases were confirmed as PTCL which were previously diagnosed as MH(1), presumed MH(3) and PTCL(7). Eight cases of 11 PTCL showed HPH mimicking MH with infiltration of the atypical malignant cells, even if the proportion of atypical malignant cells was small on bone marrow aspirates. They manifested fever and hepatomegaly but didn't have lymphadenopathy at the early stage of disease. Subtypes of PTCL with HPH were PTCL, unspecifed (3), angioimmunoblastic T cell lymphoma (1) and undetermined (4). They showed poorer outcome in 3-month survival rate (25%) than in those with PTCL without HPH(100%). CONCLUSION: These results suggest that PTCL associated with HPH should be excluded from MH by immunohistochemical analysis. Considering that prognosis of PTCL with HPH is very poor, accurate and rapid diagnosis is needed for prompt treatment.

Association of Serum Concentrations of Bilirubin with Risk of Coronary Artery Disease / 대한임상병리학회지

BACKGROUND: Bilirubin has been suggested as a antioxidant which protect oxidation of lipids and lipoproteins. Given that oxidized lipids and lipoproteins are known to be atherogenic, low serum concentrations of bilirubin could be associated with the high risk of coronary artery disease (CAD). But few studies have been performed for confirmation of this hypothesis. In this study, we evaluated the relationship between serum concentrations of billrubln and the angiographically documented CAD. METHODS: Eighty five CAD patients and 56 non-CAD patients, classified according to the maximum stenosis of coronary artery at angiography, were enrolled in this study. The degree of the coronary arterial stenosis were subclassified into or =50% (severely stenotic CAD). We retro-spectively reviewed serum concentrations of total and direct bilrubin at the time of angiography, compared tine mean concentrations of bilirubin between two groups and evaluated it in relation to the severity of CAD by statistical analysis. RESULTS: The mean concentration of total bilrubin was significant1y lower in CAD group 4han non-CAD group (12.8 micromol/L vs. 15.2 micromol/L, p value=0.04) The mean concentration of direct bilirubin was lower in CAD group than non-CAD group but not statistically significant (3.3 micromol/L vs. 4.2 micromol/L, p value=0.07). Although not significant, the concentration of total bilirubin in severely stenotic group (12.8 CAD group 12.8+/-4.3 micromol/L) was lower than mildly stenotic group (13.5+/-3.8 micromol/L) and non CAD group (15.2+/-7.4 micromol/L ) (p=0.07). CONCLUSIONS: This study showed that low serum concentrations of total bilirubin were associated with the high risk of CAD and supports the hypothesis that serum bilirubin could act as an antiatherosclerotic factor. Further prospective studies are required to confirm the relationship between bilirubin and CAD and to elucidate the most associated fraction of bilirubin and pathogenic mechanism.