A Korean Family with Thalassemia Intermedia due to Co-inheritance of Triplicated alpha-Globin Genes (alphaalpha/alphaalphaalphaanti3.7) and beta-Thalassemia Trait (IVSII-1 G -> A) / 대한혈액학회지

We report a Korean family in which the interaction of a triplicated alpha-globin locus and a heterozygous beta-thalassemia gives rise to a clinical phenotype of thalassemia intermedia. The propositus, a 36year-old woman, was evaluated because of moderately severe chronic anemia. Molecular analysis revealed heterozygosity for a single beta-thalassemia mutation, IVSII-1 (G->A). Additionally, she was found to have co-inherited a triplicated alpha-globin gene (alphaalpha/alphaalphaalphaanti3.7). In contrast, her brother heterozygous for the same triplicated alpha-locus and beta-thalassemia was clinically normal, suggesting that the delicate balance between alpha- and beta-chains is controlled by other currently not identified factors. Thalassemia intermedia due to co-inheritance of alphaalpha/alphaalphaalphaanti3.7 and IVSII-1 (G->A) was rare, and in Korea, this patient is the first case of thalassemia intermedia attributable to this combined abnormalities.

Cytogenetical, Morphological, and Immunophenotypical Characteristics of Myeloid Malignancies with t (8;21) / 대한혈액학회지

BACKGROUND: Myeloid malignancies carrying t (8;21) (q22;q22) exhibit several characteristic features. This translocation is most often associated with acute myeloid leukemia with maturation (AML-M2), but rarely with myelodysplastic syndrome. We studied the correlation of cytogenetics, morphology, and immunophenotype in 21 myeloid malignancies carrying t (8;21). METHODS: We analyzed 21 t (8;21) positive myeloid malignancies for morphology, immunophenotype and cytogenetics, retrospectively. We also performed reverse transcription polymerase chain reaction (RT-PCR) for AML1-ETO fusion transcripts using marrow slides stored at room temperature. RESULTS: 17 patients were diagnosed as French-American-British (FAB) type M2 and 4 cases as refractory anemia with excess blasts in transformation (RAEB-t). Three patients had marrow eosinophilia and 14 cases (67%) had Auer rods in leukemic blasts. Three patients (14%) developed granulocytic sarcomas. Four patients had variant t (8;21) translocation and 16 (76%) had secondary clonal abnormalities, most commonly loss of a sex chromosome (52%). 15 patients (83%) aberrantly expressed CD19. AML1-ETO fusion transcript of same size was observed in classic and variant t (8;21) translocation (11/14, 79%). CONCLUSION: Our study showed that myeloid malignancies carrying t (8;21) have distinctive morphological, immunophenotypical, and molecular features. These results can be aid to understand the pathogenesis and stratify treatment of those malignancies in the future.

Molecular Epidemiological Typing of Clinical Strains of Methicillin-Resistant Staphylococcus aureus / 대한임상미생물학회지

BACKGROUND: Meicillin-resistant Staphylococcus aureus(MRSA) is a common cause of nosocomial infections worldwide. Identification of strains by molecular typing facilitates epidemiological studies and improves disease control This study was performed to determine the usefulness of mecA-associated hypervariable region(HVR) polymerase chain reaction (PCR) and random amplified polymorphic DNA(RAPD) analysis in the investigation of a nosocomial MRSA infections. METHODS: Methicillin-resistance was identified by NCCLS disk diffusion method using the oxacillin disk. And PCR was done for detection of mecA gene. Antimicrobial susceptibility test, HVR-PCR and RAPD using 3 primers were performed for epidemiological analysis on isolates of MRSA. RESULTS: During the period from 1997 Dec. to 1998 May, 120 strains of S. aureus were isolated from clinical specimens. Among them, 78 strains were MRSA, and 72 strains were mecA positive. The strains of mecA positive MRSA were classified into four types by antibiogram, six genotypes by HVR-PCR, and 29 groups by RAPD using three primers. The combination of HVR genotypes and RAPD analysis showed 43 different types in 72 mecA positive MRSA isolates The five strains which were repeatedly isolated from the same patients showed the same HVR genotypes and RAPD analysis. CONCLUSIONS: Antibiogram, HVR-PCR, and RAPD could classify MRSA isolates into only 4-6 types, respectively, but combination of these methods could improve the typability. And combination of results of RAPD analysis using three primers were better than that using one primer in epidemiological studies of MRSA because of same reasons. It can be concluded that molecular typing of MRSA using HVR-PCR and RAPD assay is useful in epidemiolgical investigation of nosocomial infections caused by MRSA, because of its simplicity and reproducibility.

Detection of the Pallister-Killian Syndrome by G-Banding and FISH in Cultured Skin Fibroblasts / 대한임상병리학회지

Pallister-Killian syndrome is a rare disorder characterized by multiple congenital anomalies, coarse face, profound mental retardation, and epilepsy. Chromosomes of peripheral lymphocytes are usually normal, however, tissue cultures show varying degree of mosaicism for an extra metacentric chromosome i(12)(p10). We report on a two-year-old boy with Pallister-Killian syndrome confirmed by FISH in cultured skin fibroblasts. The patient had myoclonic seizures beginning at 2 months and was delayed in physical and speech development. Craniofacial manifestations include sparsity of scalp hair, hypertelorism, sparse eyebrows, flat nasal bridge, and large ears. Cytogenetic analysis of peripheral lymphocytes done at another hospital was reported to be normal. Studies of his skin fibroblasts showed an extra small metacentric i(12p) chromosome in 100% of metaphases. FISH using of whole chromosome painting probe for chromosome 12 confirmed that the supernumerary chromosome was an isochromosome 12p.

Role of Gamma Globin Promoter Region -269~-240 in Hydroxyurea Treated Erythroid Progenitor Cells / 대한임상병리학회지

BACKGROUND: Recently, a great deal of interest has been focused on the use of hydroxyurea and hemin that may augment Hb F levels in patients with hemoglobinopathies and thalassemia, although the molecular mechanism of those chemicals remains unclear. In this study, we examined the effects of hydroxyurea and hemin on human adult peripheral and cord blood erythroid cells grown in a two-phase liquid culture system. METHODS: Four adult peripheral and four cord blood cells were cultured in two-phase liquid culture, and were treated with hydroxyurea or hemin. We counted isolated erythroid cells by acid benzidine and glycophorin A stains. To determine whether transcription factor binding to the promoter is critical, we also examined the promoter region of gamma globin gene both under uninduced and hydroxyurea or hemin induced conditions using gel mobility shift assay and southwestern blot analysis. RESULTS: When added together with erythropoietin, hydroxyurea led to significant increase in the percentage of erythroid cells in cord blood. In contrast, hemin greatly accelerated hemoglobin accumulation in adult erythroid progenitor cells. At -230 and -264 regions of gamma globin gene promoter, different protein binding patterns were observed in uninduced and hydroxyurea or hemin induced conditions between adult and cord blood. CONCLUSIONS: These results suggest that hydroxyurea and hemin may act via alteration in DNA-protein interactions to induce gamma globin gene expression. In addition, we can conclude that different transcription factors may be involved in the gamma globin induction process between the adult and cord blood erythroid cells.

Quantitative Analysis of Cultured Erythroid Progenitors in Liquid System / 대한혈액학회지

BACKGROUND: Hemopoiesis and erythropoiesis have been studied mainly in immortalized cell lines and semisolid medium. But cell lines do not represent normal erythropoiesis, besides, in semisolid medium the cells are immobilized that it is difficult to do additional immunologic, biochemical, and molecular biologic experiments. In the present study we used a two-phase liquid culture system to isolate and quantify erythroid progenitors from peripheral blood and cord blood. METHODS: Peripheral and cord blood were obtained from three healthy donors and three full-term deliveries, respectively. Mononuclear cells were separated by density gradient centrifugation and were cultured in the first phase at a density of 5x106/mL in alpha- minimal essential medium ( -MEM). After 5~7 days of incubation at 37degrees C in an atmosphere of 5% CO2 with extra humidity, the nonadherent cells were harvested and recultured in the original volume of -MEM containing 10ng/mL stem cell factor and 1U/mL erythropoietin (EPO). Cellular morphology was observed by preparing cytocentrifuge slides stained with Wright Giemsa. On days 8, 10, 12, and 16 of the second phase, hemoglobin (Hb)- containing cells were counted on hemocytometer after staining with acid benzidine and glycophorin A-positive erythroid cells were scored by a flow cytometer. RESULTS: Pronormoblasts first started to appear on days 4~5 in the secondary culture. On day 10 basophilic normoblasts could be seen and on days 12~14 orthochromatic normoblasts were present. Both from peripheral and cord blood the maximum number of benzidine and glycophorin A-positive cells were achieved after 10 days and the total erythroid cell yield was approximately 1x106/mL. CONCLUSION: Using two-phase liquid culture, erythroid cell yield reached 1x106/mL both from peripheral and cord blood. In addition, this culture system permits the study of the effect of various culture conditions and components without terminating the culture, therefore it might provide us a useful experimental tool for studying pathogenesis and therapeutic modalities in genetic erythroid disorders as well as erythroid cell development.

Molecular Typing of the Methicillin-Resistant Determinant (mec) and Coagulase Typing as Epidemiologic Markers for Study of Nosocomial Infections Caused by Methicillin-Resistant Staphylococcus aureus / 대한임상병리학회지

BACKGROUND: Methicillin-resistant Staphylococcus aureus(MRSA) is an increasingly common cause of nosocomial infections worldwide. Epidemiologic investigation of MRSA outbreaks and identification of pathways of nosocomial MRSA spread require the ability to distinguish individual MRSA strains. We applied molecular tap ing of the methicillin-resistant determinant (mec) and coagulase typing in the investigation of a nosocomial MRSA infections. METHODS: We randomly selected 79 strains of mecA positive MRSA isolated from patients who visited Dong-A university Hospital from Dec. 1995 to Oct. 1996. Molecular typing of MRSA was performed by comparing the size of the mac-associated hypervariable region amplified by the polymerase chain reaction (PCR). Coagulase typing with type I-VIII antisera was also used for classification of MRSA based on its phenotype. Each isolates were classified by the combination of molecular analyses and coagulase type. RESULTS: The 79 MRSA isolates were grouped Into sin hypervariable legion (HVR) genotypes on the basis of the size of the PGR products. In coagulase typing, the most predominant type was II(46.8%) and type V was not found. Nine strains were not typable. The combination of HVR genotypes and coagulase types showed 23 different types in 79 MRSA Isolates. The strains which were repeatedly isolated from the same patients showed the same HYR genotypes and coagulate types. CONCLUSION: The combination of HVR genotypes and coagulase types is thought to be useful in epidemiolgical Investigation of nosocomial infections caused by MRSA ,because of its simplicity and reproducibility.

Identification of an i(21q) by Using Dinucleotide Repeat Polymorphisms / 대한임상병리학회지

BACKGROUND: Recent DNA polymorphism analysis using numerous DNA markers has been used to determine the parental origin of the extra chromosome 21 in Down syndrome. In this study we used seven dinucleotide repeat polymorphisms on chromosome 21 to characterize a case of rea(21q21q) and to know whether it is consistent with an isochromosome or a true Robertsonian translocation. METHODS: Cytogenetic investigation was done by conventional G banding DNA was extracted from whole blood of a proband and her parents and was amplified by PCR using seven sets of (GT)n repeat dinucleotide markers located on the long arm of chromosome 21 After electrophoresis of the PCR product in polyacrylamide gel and silver staining the parental origin and number of DNA copy were determined by visual comparison of the band intensities within and between individuals. RESULTS: Conventional cytogenetics showed that the proband had a 46.XX.re(21q21q) chromosome pattern. Parental chromosome studies were normal, therefore, the rearrangement was a de novo event. All seven DNA markers showed one or two alleles, demonstrating rea(21q21q) to be an isochromosome. For D21S215 and D21S156 markers both parents were heterozygous and the proband inherited one copy of paternal allele and two copies of maternal allele which both parents did not share. This finding was consistent with a maternally derided isochromosome. CONCLUSION: Use of dinucleotide repeat DNA polymorphisms after PCR amplification will be very useful to detect the parental origin of additional chromosome 21 or rearrangement of chromosome 21 in Down syndrome. Besides employing siltier staining of a PCR product we will be able to avoid using of radioisotopes and apply to clinical laboratory diagnosis.