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The Cellular Response to Graphene Oxide and Its Related Nano-derivatives
( Jong Wook Shin ),( Chang Seok Park ),( Jae Kook Nam ),( Young Ae Baik ),( Jae Woo Jung ),( Jae Chol Choi ),( Jae Yeol Kim ),( In Won Park ),( Byoung Whui Choi ),( Kyung Soon Choi ),( Juhyun Park ),( 대한결핵 및 호흡기학회 2012 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.114 No.0
The graphene which is an allotrope of carbon has the honeycombing structure of one-atom-thick planar sheets. it is used in modern electronic, informative technologies sensors and drug delivery system. Graphene oxide (GO) has oxygen functional groups on the graphene plane. We performed this experiment to define the cellular effect of GO. GO was prepared by the modified Hummers method using 2 g of graphite powder. After sequential procedure, GO in water was used for experiment. U-937, Raw264.7 cells and A549 cells were cultivated with GO and related nanoparticles. We checked the microscopic charac-teristics, MTT assay and Western blotting. The X-ray diffraction patterns showed that the pristine graphite had a peak centered at 2θ=26.5o (d=0.33 nm). This peak was shifted to 2θ=11.3o (d=0.78 nm) after applying the Hummers method. U937 cells aggregated sround GO. During 48 hours, modified GO with methyl group (DA-GO) and SDS-hydrazine GO(SDS-HYDrGO) diminished A549 proliferation than GO. In contrast, GO inhibited proliferation of Raw264.7 cells than DA-GO and SDS-HYD rGO. The shifting from LC3B-I to LC3B-II was minimal in GO, DA-GO, SDS-HYD rGO. In conclusion, GO in water may be phagocytosed by mononuclear cells. GO and its ligand-modified derivatives may affect differentially on proliferation or survival in airway epithelial cells and mononuclear cells. Acknowledgement: This research was supported by Mid-career Research Program (2011-0028752) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology.
Choi, Eun-Ji,Lee, Je-Hwan,Lee, Jung-Hee,Park, Han-Seung,Ko, Sun-Hye,Hur, Eun-Hye,Moon, Juhyun,Goo, Bon-Kwan,Kim, Yeonhee,Seol, Miee,Lee, Young-Shin,Kang, Young-Ah,Jeon, Mijin,Woo, Ji Min,Lee, Kyoo-Hyu Elsevier 2018 Leukemia research Vol.68 No.-
<P><B>Abstract</B></P> <P>This retrospective analysis compared anthracyclines (as part of an induction regimen) in 128 newly diagnosed <I>FLT3</I>-ITD-mutated AML patients. Induction regimens comprised high-dose daunorubicin (HD-DN; 90 mg/m<SUP>2</SUP>/d × 3d; n = 44), standard-dose daunorubicin (SD-DN; 45 mg/m<SUP>2</SUP>/d × 3d; n = 51), or idarubicin (IDA; 12 mg/m<SUP>2</SUP>/d × 3d; n = 33) in combination with cytarabine (100–200 mg/m<SUP>2</SUP>/d × 7d). Fifty-three patients showing persistent leukemia on interim bone marrow examination received a second course of induction chemotherapy comprising 2 days of daunorubicin (45 mg/m<SUP>2</SUP>/d) or IDA (8 or 12 mg/m<SUP>2</SUP>/d) in addition to 5 days of cytarabine. Complete remission (CR) rates were 77.3%, 56.9%, and 69.7% for HD-DN, SD-DN, and IDA, respectively (<I>P</I> = 0.101; HD-DN <I>vs.</I> SD-DN, <I>P</I> = 0.036; HD-DN <I>vs.</I> IDA, <I>P</I> = 0.453; IDA <I>vs.</I> SD-DN, <I>P</I> = 0.237). The HD-DN showed higher overall survival (OS) and event-free survival (EFS) than SD-DN and IDA: the differences between HD-DN and SD-DN (<I>P</I> = 0.009 for OS and <I>P</I> = 0.010 for EFS) were statistically significant.</P> <P>Results of <I>in vitro</I> studies using <I>FLT3</I>-ITD-mutated cell lines supported these findings. In conclusion, HD-DN improved the CR rate, OS, and EFS of <I>FLT3</I>-ITD-mutated AML patients. HD-DN also tended to yield better outcomes than IDA, though the difference was not significant. The superiority of HD-DN over IDA should be confirmed in future studies.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>FLT3</I>-ITD-mutated AML patients benefited from high-dose daunorubicin. </LI> <LI> High-dose daunorubicin seems to yield better results than idarubicin. </LI> <LI> The results of <I>in vitro</I> studies support these findings. </LI> </UL> </P>
Regulation of MicroRNA-Mediated Developmental Changes by the SWR1 Chromatin Remodeling Complex
Choi, Kyuha,Kim, Juhyun,Muller, Sebastian Y.,Oh, Mijin,Underwood, Charles,Henderson, Ian,Lee, Ilha American Society of Plant Biologists 2016 Plant Physiology Vol.171 No.2
<P>The ATP-dependent SWR1 chromatin remodeling complex (SWR1-C) exchanges the histone H2A-H2B dimer with the H2A.Z-H2B dimer, producing variant nucleosomes. Arabidopsis thaliana SWR1-C contributes to the active transcription of many genes, but also to the repression of genes that respond to environmental and developmental stimuli. Unlike other higher eukaryotic H2A.Z deposition mutants (which are embryonically lethal), Arabidopsis SWR1-C component mutants, including arp6, survive and display a pleiotropic developmental phenotype. However, the molecular mechanisms of early flowering, leaf serration, and the production of extra petals in arp6 have not been completely elucidated. We report here that SWR1-C is required for miRNA-mediated developmental control via transcriptional regulation. In the mutants of the components of SWR1-C such as arp6, sef, and pie1, miR156 and miR164 levels are reduced at the transcriptional level, which results in the accumulation of target mRNAs and associated morphological changes. Sequencing of small RNA libraries confirmed that many miRNAs including miR156 decreased in arp6, though some miRNAs increased. The arp6 mutation suppresses the accumulation of not only unprocessed primary miRNAs, but also miRNA-regulated mRNAs in miRNA processing mutants, hyl1 and serrate, which suggests that arp6 has a transcriptional effect on both miRNAs and their targets. We consistently detected that the arp6 mutant exhibits increased nucleosome occupancy at the tested MIR gene promoters, indicating that SWR1-C contributes to transcriptional activation via nucleosome dynamics. Our findings suggest that SWR1-C contributes to the fine control of plant development by generating a balance between miRNAs and target mRNAs at the transcriptional level.</P>
Choi, Mikyung,Lee, Kyunghee,Lee, Juhyun,Kim, Hyungsu WILEY-VCH Verlag 2007 Macromolecular symposia Vol.249 No.1
<P>Methyl methacrylate (MMA) was polymerized in the presence of polycarbonate (PC) by ultrasonic irradiation-initiated polymerization. The resulting products consisted of mixtures of homopolymers of poly(methyl methacrylate) (PMMA), PC and PC-PMMA copolymer because of the homopolymerization of MMA itself and copolymerization with macroradicals of PC. Formation of the PC-PMMA copolymer was confirmed by FTIR analysis of the reaction products after a proper extraction of free PMMA from the mixture. In order to verify the effectiveness of the PC-PMMA copolymer as a compatibilizer for PC/styrene-co- acrylonitrile (SAN) blend, 5 phr of PC-PMMA was added during melt mixing of PC/SAN in a batch mixer. It was found from the investigation of morphology and rheological properties that interphase of SAN and PC was fortified by numerous ligaments of PC-PMMA copolymer, which resulted in increase of melt viscosity and storage modulus of the blend.</P>
Choi, Yeol Kyo,Lee, Dabin,Lee, Sang Yup,Shin, Tae Joo,Park, Juhyun,Ahn, Dong June American Chemical Society 2017 Macromolecules Vol.50 No.17
<P>Revealing the nature of chain packing in conjugated polymer nanoparticles (CPNs) is one of the important issues to polymer physics research. Surfactant-stabilized CPNs in water show significantly enhanced luminescence intensity in comparison to small molecular organic dyes and single polymer chains dissolved in solvents. The importance of the conjugated polymer structure in nanomaterials is undoubted. However, details of the relationship between alignment of conjugated polymer backbone in CPNs and its luminescent property have not been established. Furthermore, there are yet no methods that can predict the atom-resolved structure of conjugated polymer in the CPNs. Herein, we employ coarse-grained (CG) molecular dynamic simulations to investigate the structure of phase-separated film and the film shattering process for a mixture of poly[2,6-(4,4-bis(2-ethylhexyl)-4<I>H</I>-cyclopenta[2,1-<I>b</I>;3,4-<I>b</I>′]-dithiophene)-<I>alt</I>-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT) and 1,2-dioctanoyl-<I>sn</I>-glycero-3-phosphocholine (D8PC). The π-π stacked structure of PCPDTBT is significantly enhanced when the ratio of D8PC increases in both dried and water exposed film. We also show that the amount of D8PC is at least 2.5 times larger than that of PCPDTBT to wrap the conjugated polymer chain, and the direct retrieval of atomistic details is achieved through back-mapping from the morphology of CG. Finally, we confirmed that conjugated backbones inside the nanoparticles were completely shielded from the aqueous solution by the dense layers of alkyl chains, resulting in remarkably enhanced chain packing. These simulated results are correlated with experimentally observed structure through UV-vis-near-infrared (UV-vis-NIR) spectrometry, scanning electron microscopy (SEM), particle size analyzer (PSA), transmission electron microscopy (TEM), and grazing-incidence X-ray diffraction (GIXD).</P> [FIG OMISSION]</BR>