Peroxiredoxin 3 Has Important Roles on Arsenic Trioxide Induced Apoptosis in Human Acute Promyelocytic Leukemia Cell Line via Hyperoxidation of Mitochondrial Specific Reactive Oxygen Species.

NB4 cell, the human acute promyelocytic leukemia (APL) cell line, was treated with various concentrations of arsenic trioxide (ATO) to induce apoptosis, measured by staining with 7-amino-actinomycin D (7-AAD) by flow cytometry. 2', 7'-dichlorodihydro-fluorescein-diacetate (DCF-DA) and MitoSOXTM Red mitochondrial superoxide indicator were used to detect intracellular and mitochondrial reactive oxygen species (ROS). The steady-state level of SO2 (Cysteine sulfinic acid, Cys-SO2H) form for peroxiredoxin 3 (PRX3) was measured by a western blot. To evaluate the effect of sulfiredoxin 1 depletion, NB4 cells were transfected with small interfering RNA and analyzed for their influence on ROS, redox enzymes, and apoptosis. The mitochondrial ROS of NB4 cells significantly increased after ATO treatment. NB4 cell apoptosis after ATO treatment increased in a time-dependent manner. Increased SO2 form and dimeric PRX3 were observed as a hyperoxidation reaction in NB4 cells post-ATO treatment, in concordance with mitochondrial ROS accumulation. Sulfiredoxin 1 expression is downregulated by small interfering RNA transfection, which potentiated mitochondrial ROS generation and cell growth arrest in ATO-treated NB4 cells. Our results indicate that ATO-induced ROS generation in APL cell mitochondria is attributable to PRX3 hyperoxidation as well as dimerized PRX3 accumulation, subsequently triggering apoptosis. The downregulation of sulfiredoxin 1 could amplify apoptosis in ATO-treated APL cells.

The psychometric properties of the korean version of the verbal abuse questionnaire in university students.

OBJECTIVE: The aim of the present study was to examine the psychometric properties of the Korean Verbal Abuse Questionnaire (K-VAQ) that consists of 15 items related with life-time verbal aggression exposure. METHODS: A total of 5814 university students who agreed to take part in the study completed the K-VAQ, the Korean version of the Life Event CheckList (LEC-K) and Impact of Event Scale-Revised (K-IES-R). Internal consistency was checked by using item-total item correlation and Cronbach's alpha coefficient. Exploratory and confirmatory factor analyses were performed, and convergent and concurrent validity levels were examined. Finally, a cluster analysis was conducted to verify the validity of the cutoff point of the K-VAQ. RESULTS: The Cronbach's alpha correlation coefficient was 0.9. The K-VAQ showed a single factor structure which explained 55.34% of the total variance. The K-VAQ was significantly associated with the LEC-K (r=0.24) and K-IES-R (r=0.28), indicating good convergent validity and concurrent validity. The cluster analysis provided four clusters of trauma experiences: high, moderate, low, and minimal, with K-VAQ ranges of 43-81, 20-42, 7-19, and 0-6, respectively. In a further investigation, a K-VAQ score of 40 was found to be the appropriate cutoff point to delineate the highly verbally abused group, as used in the previous studies. A sum of 36.5% of the highly verbally abused group reported to show substantial symptoms of PTSD (K-IES-R score >22). CONCLUSION: The present findings suggest that the K-VAQ has good psychometric properties for assessing verbal aggression among the Korean population.

Antimicrobial susceptibility of stenotrophomonas maltophilia isolates from Korea, and the activity of antimicrobial combinations against the isolates.

The aim of this study was to determine antimicrobial susceptibility of recent clinical Stenotrophomonas maltophilia isolates from Korea, and to compare the activity levels of several combinations of antimicrobials. A total of 206 non-duplicate clinical isolates of S. maltophilia was collected in 2010 from 11 university hospitals. Antimicrobial susceptibility testing was performed using the Clinical Laboratory Standards Institute agar dilution method. In vitro activity of antimicrobial combinations was tested using the checkerboard method. The susceptibility rates to trimethoprim-sulfamethoxazole and minocycline were 96% and 99%, respectively. The susceptibility rate to levofloxacin was 64%. All of four antimicrobial combinations showed synergy against many S. maltophilia isolates. A combination of trimethoprim-sulfamethoxazole plus ticarcillin-clavulanate was most synergistic among the combinations. None of the combinations showed antagonistic activity. Therefore, some of the combinations may be more useful than individual drugs in the treatment of S. maltophilia infection. Further clinical studies are warranted to validate our in vitro test results.

Simultaneous translocation of both TCR Loci (14q11) with rare partner loci (Xq22 and 12p13) in a case of T-lymphoblastic leukemia.

The most common recurrent cytogenetic abnormalities in T-lymphoblastic leukemia (T-acute lymphoblastic leukemia [T-ALL]) involve T-cell receptor (TCR) loci and a variety of partner genes, including HOX11, HOX11L2, MYC, and TAL1. In this report, we present a rare case involving simultaneous translocation of the TCR α/δ loci with different partner loci (Xq22 and 12p13); this resulted in a poor prognosis. Chromosomal analysis showed 46,Y,t(X;14)(q22;q11.2),t(12;14)(p13;q11.2) and FISH analysis by using a T-cell receptor alpha delta DNA probe, Split Signal (DakoCytomation, Denmark), showed translocations at the same TCR α/δ locus on both chromosomes. FISH with 2 bacterial artificial chromosome clones showed break apart signal, which suggests involvement of the IRS4 gene. To our knowledge, this is the first report of T-ALL in which both TCR α/δ loci were translocated with different partner loci, and 1 of the partner loci, Xq22, was a rare translocation partner locus that included IRS4 gene.

Role of OXA-23 and AdeABC efflux pump for acquiring carbapenem resistance in an Acinetobacter baumannii strain carrying the blaOXA-66 gene.

This study was performed to determine the mechanisms for acquiring carbapenem resistance in six clinical isolates of Acinetobacter baumannii. All isolates showed similar SmaI-macrorestriction patterns with less than 3 band differences by PFGE. The isolates showed a high level resistance (>32 mg/L) to both imipenem and meropenem by Etest. Phe-Arg-beta-naphthylamide lowered the MICs of carbapenems. Real-time PCR experiments showed that expression levels of the adeB gene in the six A. baumannii isolates were 10- to 40-times higher than those of imipenem-susceptible strains. Direct sequencing of PCR products showed that all isolates carried the bla(OXA-23) gene, which was preceded by ISAba1. The bla(OXA-23) probe hybridized with approximately 500-kb I-CeuI chromosomal fragments, but not with a plasmid. These findings suggest that overexpression of the AdeABC efflux pump as well as chromosome-borne OXA-23 may play a role in acquiring carbapenem resistance in our A. baumannii isolates.

The effect of methylphenidate on Internet video game play in children with attention-deficit/hyperactivity disorder.

OBJECTIVE: A number of studies about attention-deficit/hyperactivity disorder (ADHD) and Internet video game play have examined the prefrontal cortex and dopaminergic system. Stimulants such as methylphenidate (MPH), given to treat ADHD, and video game play have been found to increase synaptic dopamine. We hypothesized that MPH treatment would reduce Internet use in subjects with co-occurring ADHD and Internet video game addictions. METHODS: Sixty-two children (52 males and 10 females), drug-naive, diagnosed with ADHD, and Internet video game players, participated in this study. At the beginning of the study and after 8 weeks of treatment with Concerta (OROS methylphenidate HCl, Seoul, Korea), participants were assessed with Young's Internet Addiction Scale, Korean version (YIAS-K), Korean DuPaul's ADHD Rating Scale, and the Visual Continuous Performance Test. Their Internet usage time was also recorded. RESULTS: After 8 weeks of treatment, the YIAS-K scores and Internet usage times were significantly reduced. The changes in the YIAS-K scores between the baseline and 8-week assessments were positively correlated with the changes in total and inattention scores from the Korean DuPaul's ADHD Rating Scale, as well as omission errors from the Visual Continuous Performance Test. There was also a significant difference in the number of omission errors among non-Internet-addicted, mildly Internet addicted, and severely Internet addicted participants. DISCUSSION: We suggest that Internet video game playing might be a means of self-medication for children with ADHD. In addition, we cautiously suggest that MPH might be evaluated as a potential treatment of Internet addiction.

Mutation analysis of PAH gene and characterization of a recurrent deletion mutation in Korean patients with phenylketonuria.

Phenylketonuria (PKU; MIM 261600) is an autosomal recessive metabolic disorder caused by a deficiency of phenylalanine hydroxylase (PAH; EC 1.14.16.1). Point mutations in the PAH gene are known to cause PKU in various ethnic groups, and large deletions or duplications account for up to 3% of the PAH mutations in some ethnic groups. However, a previous study could not identify approximately 14% of the mutant alleles by sequence analysis in Korean patients with PKU, which suggests that large deletions or duplication might be frequent causes of PKU in Koreans. To test this hypothesis, we performed multiplex ligation-dependent probe amplification (MLPA) for the identification of uncharacterized mutant alleles after PAH sequence analysis of 33 unrelated Korean patients with PKU. Bi-directional sequencing of the PAH exons and flanking intronic regions revealed 27 different mutations, including four novel mutations (two missense and two deletion mutations), comprising 57/66 (86%) mutant alleles. MLPA identified a large deletion that encompassed exons 5 and 6 in four patients, another large deletion that extended from exon 4 to exon 7 in one patient, and a duplication of exon 4 in one patient. Chromosomal walking characterized the deletion breakpoint of the most common large deletion that involved exons 5 and 6 (c.456_706+138del). The present study shows that the allelic frequency of exon deletion or duplication is 9% (6/66) in Korean PKU patients, which suggests that these mutations may be frequent causes of PKU in Korean subjects.

Adherent cells generated during long-term culture of human umbilical cord blood CD34+ cells have characteristics of endothelial cells and beneficial effect on cord blood ex vivo expansion.

Hematopoiesis depends on the association of hematopoietic stem cells with stromal cells that constitute the hematopoietic microenvironment. The in vitro development of the endothelial cell from umbilical cord blood (UCB) is not well established and has met very limited success. In this study, UCB CD34(+) cells were cultured for 5 weeks in a stroma-free liquid culture system using thrombopoietin, flt3 ligand, and granulocyte-colony stimulating factor. By week 4-5, we found that firmly adherent fibroblast-like cells were established. These cells showed characteristics of endothelial cells expressing von Willebrand factor, human vascular cell adhesion molecule-1, human intracellular adhesion molecule-1, human CD31, E-selectin, and human macrophage. Furthermore, when comparing an ex vivo system without an established endothelial monolayer to an ex vivo system with an established endothelial monolayer, better expansion of total nucleated cells, CD34(+) cells, and colony-forming units (CFUs)-granulocyte-macrophage and CFUs-granulocyte-erythroid-megakaryocyte-macrophage were found during culture. This phenomenon was in part due to the fact that a significant reduction of apoptotic fractions was found in the CD34(+) cells, which were cultured on the adherent monolayer for up to 5 weeks. To gather quantitative data on the number of endothelial cells derived from a given number of CD34 cells, we performed limiting dilution assay by using Poisson distribution: the number of tested cells (linear scale) producing a 37% negative culture (logarithmic scale) is the number of cells containing one endothelial cell. By this method, one endothelial cell may be found from 314 CD34(+) cells after 5 weeks of culture. These results suggest that the UCB CD34(+) cell fraction contains endothelial cell precursors, establishing the hematopoietic microenvironment and providing the beneficial effects through downregulating apoptosis on UCB expansion protocols. These observations may provide insight for future cellular therapy or graft engineering.