Sang-Guk Lee, M.D. Dr. Lee is a resident at the Department of Laboratory Medicine, Yonsei University College of Medicine in South Korea. He received his M.D. degree at Yonsei University College of Medicine in Seoul, Korea (1999-2005). He also received his training of internship at the Severance Hospital, Yonsei University College of Medicine (2005-2006).
Abstract: This study was to determine the prevalence and characteristics of CTX-M-type extended-spectrum beta-lactamases (ESBLs) in nonduplicate Escherichia coli (n=760) and Klebsiella pneumoniae (n=379) bloodstream isolates collected during January 2005 to October 2007 at a university hospital (2000 beds) in Seoul, Korea. Antimicrobial susceptibilities were determined by disk diffusion and agar dilution methods. The double-disk synergy test detected ESBLs in 8.7% (66/760) of E. coli and 11.3% (43/379) of K. pneumoniae isolates. Polymerase chain reaction detected bla(CTX-M) in 60/66 (90.9%) E. coli and 9/43 (20.9%) K. pneumoniae isolates with the ESBL phenotype. CTX-M-14 was the most common type of CTX-M ESBLs in both E. coli (n=32) and K. pneumoniae (n=6). CTX-M-15 was the 2nd most common type of CTX-M ESBLs in E. coli (n=22), but it was not detected in K. pneumoniae. In addition, CTX-M-24 (n=2), CTX-M-65 (n=2), CTX-M-27 (n=1), and CTX-M-32 (n=1) were detected for the 1st time in Korea.
Abstract: Acute myelogenous leukemia (AML) with t(8;21)(q22;q22) demonstrates unique clinico-pathologic disease entity in patients with hematologic malignancies. The t(8;21), which results in fusion of the AML1 gene on 21q22 and the ETO gene on 8q22 on a molecular level, is one of the most common nonrandom chromosomal changes, and it is found in about 5-12% of patients with AML. Among these cases, complex variants involving chromosomes 8 and 21, as well as a third or fourth chromosome, account for approximately 6-10% of patients with an AML1/ETO chimeric gene, and about 100 variant cases with AML1/ETO fusion transcript have been reported in the literature. Here, we describe a rare case report of reciprocal paracentric inversion-associated t(8;21) variant in a 28-year old male patient with de novo AML. The abnormal results of conventional cytogenetics and interphase fluorescent in situ hybridization in this patient drove us to perform further studies and a literature review. This report emphasizes the value of "conventional" cytogenetics, as well as "newly developed" molecular cytogenetic methods in the diagnosis of rare complex t(8;21) variant in patients with AML.
Abstract: We report a rare case of acute myeloid leukemia (AML) with t(6;11)(q15;q23) in a 50-year-old female showing a poor prognosis. Bone marrow biopsy revealed markedly hypercellular marrow with infiltrates of myeloblasts, consistent with AML-M2 morphology. The karyotype of this patient was 46,XX,t(6;11)(q15;q23) in all analyzed cells, and the results of fluorescence in situ hybridization (FISH) and multi-color FISH analysis confirmed this unique MLL rearrangement as a sole abnormality. To our knowledge, t(6;11)(q13 approximately q15;q23) is the most rare type of MLL rearrangement involving the long arm of chromosome 6. Only two cases with t(6;11)(q13;q23) and three cases with t(6;11)(q15;q23) have been reported, but detailed clinical or laboratory data were not available. From this report, it is apparent that in a cytogenetic laboratory, the accurate detection of a rare type of MLL rearrangement is very important in the differential diagnosis, prompt treatment, and prediction of prognosis of leukemias.
Abstract: Trisomy 8 is one of the most frequent numerical chromosomal abnormalities observed in hematological malignancies, whereas tetrasomy 8 is a clonal aberration seen mainly in myeloid disorders such as acute myelod leukemia (AML) and myelodysplastic syndromes. In contrast to trisomy 8, tetrasomy 8 is a rare chromosomal aberration, in that only 17 reported AML cases with isolated tetrasomy 8 have been documented. Interestingly, the majority of reported cases were associated with monocytic-lineage leukemias. According to recent reports, tetrasomy 8 is regarded as a poor prognostic factor, and most patients having this abnormality relapsed and died within 1 yr. Here, we report a patient with acute monoblastic leukemia having tetrasomy 8 and a very aggressive disease course.
Abstract: A 25-year old man with a 30 month history of proptosis and pain of the right eye was referred to Severance Hospital of Yonsei University. Orbital computed tomography (CT) demonstrated a huge mass in the right retrobulbar orbit; an incisional biopsy and orbitotomy were performed for diagnosis and orbital soft tissue decompression. Subsequent histopathology disclosed sheets of mononuclear cells in the orbital mass, and immunohistochemical stains demonstrated positive results for myeloperoxidase and CD43, which supported the diagnosis of granulocytic sarcoma (GS). After his 1-year follow-up, the patient presented with pancytopenia, and an ensuing bone marrow aspiration revealed markedly hypercellular marrow replaced by many large abnormal myeloblasts. The patient was diagnosed with acute myelogenous leukemia with t(8;21) preceded by orbital GS. Orbital GS is primarily a disease of children, and extremely rare in adults. To the best of our knowledge, only four cases of this disease in adults have been reported in the literature. Our case is the first report of preceding orbital GS in an adult patient with a complex karyotype including t(8;21).
Abstract: BACKGROUND AND OBJECTIVES: In peripheral blood stem cell transplantation, the number of CD34(+) cells infused is considered a predictor of haematopoietic engraftment. However, the currently accepted minimal threshold of CD34(+) cells/kg was determined by counting CD34(+) cells before freezing, and the loss of viable CD34(+) cells during freezing, cryopreservation or thawing prior to reinfusion has not been assessed. MATERIALS AND METHODS: Total and viable CD34(+) cells were quantified using single platform flow cytometry and viability dye, 7-amino actinomycin D (7-ADD), at the time of collection and prior to reinfusion in 46 peripheral haematopoietic stem cell grafts from 36 patients. The time to engraftment of neutrophil and platelet was assessed by routine peripheral blood cell counts performed daily. RESULTS: The median number of viable CD34(+) cells harvested was 3.6 x 10(6)/kg (range 0.05-21.2), and the median viability was 98% (range 70-100%) before freezing. After thawing, the median number of viable CD34(+) cells was reduced to 2.2 x 10(6)/kg (range 0.04-14.8) and the median viability was reduced to 71% (range 31-89%). The number of viable CD34(+) cells/kg before freezing and after thawing significantly correlated with engraftment of neutrophils (P < 0.0001 both) and platelets (P = 0.007 and 0.006, respectively). Although the minimum dose for engraftment (2.0 x 10(6) CD34(+) cells/kg) was harvested in 37 of 46 cases (85%), only 25 cases (54%) met this threshold at the time of reinfusion. For platelet engraftment, determination of viable CD34(+) cells prior to reinfusion was more important than enumeration at the time of collection. CONCLUSION: Quantification of post-thaw viable CD34(+) cells better represents the actual composition of the graft and may be a more accurate predictor of haematopoietic engraftment than post-thaw total CD34(+) cell counts, or prefreeze determinations, especially for platelet engraftment. It is necessary to develop good quality controls for freezing and thawing procedures to minimize variance in cell viability.
Abstract: BACKGROUND: Blood culture is important for the determination of the etiologic agent of bacteremia. Analysis of blood culture results and antimicrobial susceptibility trend can provide clinicians with relevant information for the empirical treatment of patients. METHODS: The species and antimicrobial susceptibility of the isolates from blood cultures at the Severance Hospital during 1994-2003 were analysed. Blood specimens were cultured for 7 days using tryptic soy broth and thioglycollate medium. Identification of organism was based on conventional methods or commercial kit systems. Antimicrobial susceptibility was tested by a disk diffusion method. RESULTS: Of 536,916 blood specimens cultured, 24,877 (4.6%) from 13,102 patients were positive. Among the isolates, 93.1% were aerobic or facultative anaerobic bacteria, 3.3% anaerobes, and 3.6% fungi. Escherichia coli was isolated most frequently, followed by Staphylococcus aureus, alpha-hemolytic Streptococcus, Enterococcus spp., and Klebsiella pneumoniae. The proportion of patients with Enterococcus faecium and K. pneumoniae gradually increased during this study. Enterococcus, S. aureus and alpha-hemolytic Streptococcus were frequently isolated from the age group of less than 2 yr. E. coli, Enterococcus spp., K. pneumoniae and S. aureus from the age group of over 50 yr. Oxacillin-resistant S. aureus decreased, whereas vancomycin-resistant E. faecium and imipenemresistant Pseudomonas aeruginosa and Acinetobacter baumannii increased. CONCLUSIONS: E. coli was the most common cause of bacteremia and S. aureus, alpha-hemolytic Streptococcus, and K. pneumoniae were frequently isolated pathogens. The bacteremia due to Enterococcus, K. pneumoniae, fungi, vancomycin-resistant E. faecium, and imipenem-resistant P. aeruginosa and A. baumannii gradually increased during this period.
Abstract: Valproic acid (VPA) is a commonly prescribed anticonvulsant drug for the treatment of various forms of epilepsy. Concomitant administration of VPA and carbapenem antibiotics such as panipenem/ betamipron and meropenem has been reported to decrease the serum level of VPA. We observed seven cases which showed a decrease in serum levels of VPA due to concomitant use of VPA and carbapenem from January 2002 to October 2006 in a 750-bed university hospital, the average decrease of 70.4% was observed. Carbapenem antibiotics administrated concomitantly with VPA were panipenem (1 case), meropenem (3 cases), and imipenem (2 cases), and in one other case imipenem and meropenem were used sequentially. We found the VPA serum levels were significantly decreased with meropenem (n=4) more than with other carbapenem antibiotics (n=4, 89.3% vs. 51.5% decrease, P=0.03). Clinicians should be aware of this potential interaction, pay attention to the failure of seizure control due to decreased serum VPA levels with concomitant use of carbapenem antibiotics, and monitor VPA serum levels for those cases.
Abstract: A rare karyotypic event, der(1;15)(q10;q10), which involves the whole long arms of chromosomes 1 and 15, has been reported in patients with various conditions, including acute myelogenous leukemia, myelodysplastic syndrome, polycythemia vera, and multiple myeloma. Only 27 cases of unbalanced der(1;15)(q10;q10) have been documented in the literature as single or complexed chromosomal abnormalities in hematological malignancies. Here, we describe two cases of acute lymphoblastic leukemia with der(1;15)(q10;q10), and review the previous reports. Although more case studies are needed, we suggest that der(1;15)(q10;q10) should be considered a nonrandom chromosomal abnormality in hematological malignancies including both lymphoid and myeloid neoplasms.
Abstract: A 56-year-old woman was brought to the emergency room with gum swelling and pain. Biopsy of the gingiva revealed sheet-like proliferation of myeloperoxidase and CD45-positive large cells, and she was diagnosed with granulocytic sarcoma. Two years later, bone marrow involvement of granulocytic sarcoma was suspected. Her chromosome study repeatedly revealed a 46,XX,t(5;12)(q13;p13) karyotype. Case reports of t(5;12)(q13;p13) are extremely rare in the literature. To our knowledge, this is the first report of t(5;12)(q13;p13) in a patient with acute myelogenous leukemia with preceding granulocytic sarcoma.
