Radotinib induces high cytotoxicity in c-KIT positive acute myeloid leukemia cells

Heo, S.K.,Noh, E.K.,Kim, J.Y.,Jo, J.C.,Choi, Y.,Koh, S.,Baek, J.H.,Min, Y.J.,Kim, H. North-Holland 2017 European journal of pharmacology Vol.804 No.-

<P>Previously, we reported that radotinib, a BCR-ABL1 tyrosine kinase inhibitor, induced cytotoxicity in acute myeloid leukemia (AML) cells. However, the effects of radotinib in the subpopulation of c-KIT-positive AML cells were unclear. We observed that low-concentration radotinib had more potent cytotoxicity in c-KIT-positive cells than c-KIT-negative cells from AML patients. To address this issue, cell lines with high c-KIT expression, HEL92.1.7, and moderate c-KIT expression, H209, were selected. HEL92.1.7 cells were grouped into intermediate and high c-HIT expression populations. The cytotoxicity of radotinib against the HEL92.1.7 cell population with intermediate c-HIT expression was not different from that of the population with high c-KIT expression. When H209 cells were grouped into c-KIT expression-negative and c-HIT expression-positive populations, radotinib induced cytotoxicity in the c-KIT-positive population, but not the c-KIT-negative population. Thus, radotinib induces cytotoxicity in c-KIT-positive cells, regardless of the c-KIT expression intensity. Therefore, radotinib induces significant cytotoxicity in c-KIT-positive AML cells, suggesting that radotinib is a potential target agent for the treatment of c-KIT-positive malignancies including AML.</P>

Manganese does not alter the severe neurotoxicity of MPTP

Baek, S Y,Kim, Y H,Oh, S O,Lee, C-R,Yoo, C I,Lee, J H,Lee, H,Sim, C S,Park, J,Kim, J-W,Yoon, C S,Kim, Y Scientific & Medical Division,Macmillan Press 2007 Human & experimental toxicology Vol.26 No.3

<P>We utilized a mice model of Parkinsonism: (1) to evaluate 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity; and (2) to evaluate whether manganese (Mn) exposure can affect MPTP-induced neurotoxicity. A 2 × 3 experimental design (MPTP ×± Mn) was as follows: SS, MPTP(-) × Mn(-); SLMn, MPTP(-) × low Mn(+); SHMn, MPTP(-) × high Mn(+); MpS, MPTP(+) × Mn(-); MpLMn, MPTP(+) × low Mn(+); MpHMn, MPTP(+) × high Mn(+). We administered MPTP (30 mg/kg per day) to male C57BL/6 mice intraperitoneally, once a day for 5 days. Subsequently, mice were treated with either 2 or 8 mg/kg of MnCl<SUB>2</SUB>.4H<SUB>2</SUB>O intraperitoneally, once a day for 3 weeks.</P><P>Blood and striatal Mn levels were elevated in the Mnexposed groups. The number of tyrosine hydroxylase (TH)-immunoreactive (ir) neurons in the substantia nigra pars compacta were decreased significantly in the MPTP-exposed groups. The densities of TH-ir axon terminals in caudate-putamen (CPU) were significantly decreased in the MPTP-treated groups. However, Mn treatment did not affect MPTP neurotoxicity. The densities of glial fibrillary acidic protein (GFAP)-ir astrocytes in the CPU or globus pallidus were significantly increased in the MPTP-treated groups. Concentrations of dopamine in the striatum were decreased significantly in the MPTP-exposed groups only, but Mn had no effect.</P>

<i>Rhodococcus aerolatus</i> sp. nov., isolated from subarctic rainwater

Hwang, C. Y.,Lee, I.,Cho, Y.,Lee, Y. M.,Baek, K.,Jung, Y.-J.,Yang, Y. Y.,Lee, T.,Rhee, T. S.,Lee, H. K. International Union of Microbiological Societies 2015 International journal of systematic and evolutiona Vol.65 No.2

<P>A Gram-stain-positive, rod-shaped and non-motile strain, designated PAMC 27367<SUP>T</SUP>, was isolated from rainwater collected on the Bering Sea. Analysis of the 16S rRNA gene sequence of the strain showed an affiliation with the genus <I>Rhodococcus</I>. Phylogenetic analyses revealed that strain PAMC 27367<SUP>T</SUP> formed a robust clade with the type strains of <I>Rhodococcus rhodnii</I>, <I>Rhodococcus aetherivorans</I> and <I>Rhodococcus ruber</I> with 16S rRNA gene sequence similarities of 96.3 %, 95.8 % and 95.5 %, respectively. Cells of the strain grew optimally at 25 °C and at pH 6.5–7.0 in the presence of 0–2 % (w/v) sea salts. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and three unknown phospholipids. The major cellular fatty acids (>10 %) were iso-C<SUB>16 : 0</SUB>, C<SUB>17 : 1</SUB>ω8<I>c</I> and 10-methyl C<SUB>17 : 0</SUB>. Cell wall analysis showed that strain PAMC 27367<SUP>T</SUP> contained <I>meso</I>-diaminopimelic acid. The genomic DNA G+C content was 77.1 mol%. Based on the phylogenetic, chemotaxonomic and phenotypic data presented here, we propose a novel species with the name <I>Rhodococcus</I> <I>aerolatus</I> sp. nov., with PAMC 27367<SUP>T</SUP> ( = KCTC 29240<SUP>T</SUP> = JCM 19485<SUP>T</SUP>) as the type strain.</P>

Comprehensive study on critical role of surface oxygen vacancies for 2DEG formation and annihilation in LaAlO3/SrTiO3 heterointerfaces

Moon, S. Y.,Moon, C. W.,Chang, H. J.,Kim, T.,Kang, C. Y.,Choi, H. J.,Kim, J. S.,Baek, S. H.,Jang, H. W. Springer Science + Business Media 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.2

<P>Here we report comprehensive study of 2DEG at a-LAO/STO interfaces in comparison with 2DEG at crystalline LaAlO3 (c-LAO)/STO interfaces. We observe that the oxygen deficient environment during the deposition of LAO overlayer is essentially required to create 2DEG at LAO/STO interface regardless of growth temperature from 25 degrees C to 700 degrees C, indicating that the oxygen-poor condition in the system is more important than the crystallinity of LAO layer. The critical thickness (2.6 nm) of 2DEG formation at a-LAO/STO heterostructure is thicker than (1.6 nm) that at c-LAO/STO. Upon ex-situ annealing at 300 degrees C under 300 mTorr of oxygen pressure, 2DEG at a-LAO/STO interface is annihilated, while that in c-LAO/STO interface is still maintained. With combing these findings and scanning transmission electron microscope (STEM) analysis, we suggest that oxygen vacancies at the LAO surface is attributed to the origin of 2DEG formation at the LAO/STO and the crystallinity of the LAO overlayer plays a critical role in the annihilation of 2DEG at a-LAO/STO interface rather than in the formation of 2DEG. This work provides a framework to understand the importance of prohibiting the LAO surface from being oxidized for achieving thermally stable 2DEG at a-LAO/STO interface.</P>

Ultraviolet photodissociation spectroscopy of cold, isolated adenine complexes with a potassium cation

Baek, J.Y.,Choi, C.M.,Eun, H.J.,Park, K.S.,Choi, M.C.,Heo, J.,Kim, N.J. North Holland 2015 Chemical physics letters Vol.635 No.-

We obtain the ultraviolet photodissociation spectrum of adenine complexes with K<SUP>+</SUP> ion stored in a cold ion trap. The spectrum near the origin band of the S<SUB>0</SUB>-S<SUB>1</SUB> transition exhibits well-resolved vibronic bands, all of which are assigned from a single isomer by UV-UV hole-burning (HB) spectroscopy. Comparing the spectrum with theoretical spectra, we determine the structure of the isomer, where K<SUP>+</SUP> is bound not to 9H-adenine (A9) but to 7H-adenine (A7). We suggest that K<SUP>+</SUP>A7 ions are formed in solution through tautomerization, for which the energy barrier varies greatly depending on the binding site of the K<SUP>+</SUP> ion on A9.

Decrosslinking reaction kinetics of silane-crosslinked polyethylene in sub- and supercritical fluids

Baek, B.K.,La, Y.H.,Lee, A.S.,Han, H.,Kim, S.H.,Hong, S.M.,Koo, C.M. Applied Science Publishers ; Elsevier Science Ltd 2016 Polymer degradation and stability Vol.130 No.-

Supercritical methanol is a popular fluid as a supercritical medium for decrosslinking reaction of crosslinked polyethylene. However, due to its toxicity, a safe alternative medium is much to be desired. In this work, various sub- and supercritical fluids with different polarity characters were investigated to find a safe alternative medium for continuous decrosslinking of silane-crosslinked polyethylene (S-XLPE). Like methanol, all examined fluids, including ethanol, propanol, and water, exhibited first-order reaction kinetics regarding the gel content in the continuous decrosslinking process. The reaction rate constant values were observed as 2.806, 2.569, 2.383, and 2.130 min<SUP>-1</SUP> in supercritical methanol, supercritical ethanol, supercritical 2-propanol, and subcritical water at 380 <SUP>o</SUP>C, respectively. As a non-toxic fluid with reaction kinetics very comparable to that of methanol, ethanol was found to be the best alternative medium for the continuous decrosslinking reaction of S-XLPE.

스노우보더의 손상 : 스노우보더의 수근관절 Snowboarder`s Wristase

김정환,최영준,백승기,김유진,황재광,안형선,박경준,안현태,조재우 대한스포츠의학회 2002 대한스포츠의학회지 Vol.20 No.1

Prevalence of antimicrobial resistant Streptococcus pneumoniae serotype 11A isolates in Korea, during 2004-2013, due to the increase of multidrug-resistant clone, CC166

Baek, J.Y.,Kim, S.H.,Kang, C.I.,Chung, D.R.,Peck, K.R.,Ko, K.S.,Song, J.H. Elsevier Science 2016 INFECTION GENETICS AND EVOLUTION Vol.38 No.-

Since the introduction of the pneumococcal conjugate vaccine (PCV7) in Korea in 2003, the proportion of non-vaccine serotypes has increased. Among non-vaccine serotypes, serotype 11A is highly prevalent in Korea. We investigated the prevalence and characteristics of Streptococcus pneumoniae serotype 11A isolates in a Korean tertiary-care hospital, during 2004-2013. A total of 1579 non-duplicate clinical S. pneumoniae isolates, collected from 2004 to 2013, were included in this study. Serotype was determined by the capsular Quellung method, and in vitro susceptibility testing was performed by broth microdilution method. Multilocus sequence typing was performed to determine the genotypes of the S. pneumoniae isolates. We identified 90 serotype 11A isolates (5.7%). During this period, the proportion of serotype 11A has increased from 3.2% up to 13.2% (in 2012). Among the serotype 11A isolates, two main clonal complexes (CCs), CC166 and CC99, were identified. The increase of serotype 11A was mainly due to the increase of CC166 isolates, which have high antimicrobial resistance rates. In addition, we identified that 14 isolates, belonging to ST8279, ST9875, and ST3598 of CC166, were non-susceptible to all antimicrobial agents tested in this study. We identified the increase of S. pneumoniae serotype 11A in Korea, which mainly due to the expansion of a resistant clonal group, CC166.

Silicate 유리의 Mossbauer 분광학적 연구

홍성락,문찬호,홍치유,백승도,최달하 동국대학교 자연과학연구소 1986 자연과학연구 논문집 Vol.6 No.-

10Nio-10Fe₂O₃-30Na₂O-50SiO₂유리에 대한 Mossbauer 분광학적인 연구를 저온실험과 유리의 열처리효과에 대해 수행하엿다. center shift 와 quadrupole splitting 및 공명흡수 면적은 저온으로 갈수록 증가하였으며, 유리의 Dabye 및 Einsteine 온도는 각각 450K 와 352K 이었다. 열처리온도가 증가함에 따라 I.S. 와 Q.S. 는 감소하였으며, 특히 710℃이상에서 열처리한 시료는 NiFe₂O₄에 의한 magnetic hyperfine splitting이 관찰되었다. Using the 10Nio-10Fe₂O₃-30Na₂O-50SiO₂glass, we investigated the Mossbauer parameters of quenched glass and heat-treated glasses. The Debye and Einstein temperature of the quenched glass were determined by the center shifr and the kinetic tmeperature. According to the X-ray diffraction patterns, NiFe₂O₄was precipitated in the glass by heat treatment. Both the isomer shift and quadrupale splitting were decreased as the heat treatment temperature increased. The glasses, heat-treated above 710℃, showed magnetic hyperfine splitting for NiFe₂O₄.

Osteopontin plays a key role in vascular smooth muscle cell proliferation via EGFR-mediated activation of AP-1 and C/EBPβ pathways

Lee, S.J.,Baek, S.E.,Jang, M.A.,Kim, C.D. Academic Press 2016 PHARMACOLOGICAL RESEARCH Vol.108 No.-

Osteopontin (OPN) is known as an active player in the progression of vascular remodeling diseases, however, the precise role in the proliferation of vascular smooth muscle cells (VSMC) is unclear. Thus, this study investigated the role of OPN in VSMC proliferation induced by 4-hydroxynonenal (HNE), and identified the intracellular signaling pathways involved in 4-HNE-induced OPN production. In VSMC primary cultured from rat thoracic aorta as well as in VSMC in the media of aorta, HNE enhanced OPN expression in concentration-dependent manners. Both the proliferation of cultured VSMC and PCNA positive cells in aortic tissues were also increased by HNE, which were attenuated in OPN-deficient cells and aortic tissues isolated from OPN-deficient mice, indicating a pivotal role of OPN in HNE-induced VSMC proliferation. In the promoter assay, HNE increased OPN promoter activity, which was attenuated when the regions harboring AP-1 and C/EBPβ binding sites were mutated. The increased bindings of AP-1 and C/EBPβ to the OPN promoter were also demonstrated by ChIP analysis. In addition, the increases in both OPN expression and the activities of AP-1 and C/EBPβ by HNE were attenuated by AG1478, an EGFR antagonist. Based on these results, it was suggested that HNE induced OPN expression in VSMC via signaling pathways involving AP-1 and C/EBPβ, leading to increases in VSMC proliferation and subsequent vascular remodeling.