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Kwon M, Kim DJ, Cho H, Yang S. The smartphone addiction scale: development and validation of a short version for adolescents. PLoS One 2013; 8:e83558. [PMID: 24391787 PMCID: PMC3877074 DOI: 10.1371/journal.pone.0083558] [Citation(s) in RCA: 725] [Impact Index Per Article: 60.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 11/05/2013] [Indexed: 11/18/2022] Open
Abstract
Objective This study was designed to investigate the revised and short version of the smartphone addiction scale and the proof of its validity in adolescents. In addition, it suggested cutting off the values by gender in order to determine smartphone addiction and elaborate the characteristics of smartphone usage in adolescents. Method A set of questionnaires were provided to a total of 540 selected participants from April to May of 2013. The participants consisted of 343 boys and 197 girls, and their average age was 14.5 years old. The content validity was performed on a selection of shortened items, while an internal-consistency test was conducted for the verification of its reliability. The concurrent validity was confirmed using SAS, SAPS and KS-scale. Receiver operating characteristics analysis was conducted to suggest cut-off. Results The 10 final questions were selected using content validity. The internal consistency and concurrent validity of SAS were verified with a Cronbach's alpha of 0.911. The SAS-SV was significantly correlated with the SAS, SAPS and KS-scale. The SAS-SV scores of gender (p<.001) and self-evaluation of smartphone addiction (p<.001) showed significant difference. The ROC analysis results showed an area under a curve (AUC) value of 0.963(0.888–1.000), a cut-off value of 31, sensitivity value of 0.867 and specificity value of 0.893 in boys while an AUC value of 0.947(0.887–1.000), a cut-off value of 33, sensitivity value of 0.875, and a specificity value of 0.886 in girls. Conclusions The SAS-SV showed good reliability and validity for the assessment of smartphone addiction. The smartphone addiction scale short version, which was developed and validated in this study, could be used efficiently for the evaluation of smartphone addiction in community and research areas.
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Validation Study |
12 |
725 |
2
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Burdick D, Soreghan B, Kwon M, Kosmoski J, Knauer M, Henschen A, Yates J, Cotman C, Glabe C. Assembly and aggregation properties of synthetic Alzheimer's A4/beta amyloid peptide analogs. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)48529-8] [Citation(s) in RCA: 702] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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33 |
702 |
3
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Kwon M, Lee JY, Won WY, Park JW, Min JA, Hahn C, Gu X, Choi JH, Kim DJ. Development and validation of a smartphone addiction scale (SAS). PLoS One 2013; 8:e56936. [PMID: 23468893 PMCID: PMC3584150 DOI: 10.1371/journal.pone.0056936] [Citation(s) in RCA: 548] [Impact Index Per Article: 45.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Accepted: 01/18/2013] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE The aim of this study was to develop a self-diagnostic scale that could distinguish smartphone addicts based on the Korean self-diagnostic program for Internet addiction (K-scale) and the smartphone's own features. In addition, the reliability and validity of the smartphone addiction scale (SAS) was demonstrated. METHODS A total of 197 participants were selected from Nov. 2011 to Jan. 2012 to accomplish a set of questionnaires, including SAS, K-scale, modified Kimberly Young Internet addiction test (Y-scale), visual analogue scale (VAS), and substance dependence and abuse diagnosis of DSM-IV. There were 64 males and 133 females, with ages ranging from 18 to 53 years (M = 26.06; SD = 5.96). Factor analysis, internal-consistency test, t-test, ANOVA, and correlation analysis were conducted to verify the reliability and validity of SAS. RESULTS Based on the factor analysis results, the subscale "disturbance of reality testing" was removed, and six factors were left. The internal consistency and concurrent validity of SAS were verified (Cronbach's alpha = 0.967). SAS and its subscales were significantly correlated with K-scale and Y-scale. The VAS of each factor also showed a significant correlation with each subscale. In addition, differences were found in the job (p<0.05), education (p<0.05), and self-reported smartphone addiction scores (p<0.001) in SAS. CONCLUSIONS This study developed the first scale of the smartphone addiction aspect of the diagnostic manual. This scale was proven to be relatively reliable and valid.
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Research Support, Non-U.S. Gov't |
12 |
548 |
4
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Haug S, Castro RP, Kwon M, Filler A, Kowatsch T, Schaub MP. Smartphone use and smartphone addiction among young people in Switzerland. J Behav Addict 2015; 4:299-307. [PMID: 26690625 PMCID: PMC4712764 DOI: 10.1556/2006.4.2015.037] [Citation(s) in RCA: 383] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND AND AIMS Smartphone addiction, its association with smartphone use, and its predictors have not yet been studied in a European sample. This study investigated indicators of smartphone use, smartphone addiction, and their associations with demographic and health behaviour-related variables in young people. METHODS A convenience sample of 1,519 students from 127 Swiss vocational school classes participated in a survey assessing demographic and health-related characteristics as well as indicators of smartphone use and addiction. Smartphone addiction was assessed using a short version of the Smartphone Addiction Scale for Adolescents (SAS-SV). Logistic regression analyses were conducted to investigate demographic and health-related predictors of smartphone addiction. RESULTS Smartphone addiction occurred in 256 (16.9%) of the 1,519 students. Longer duration of smartphone use on a typical day, a shorter time period until first smartphone use in the morning, and reporting that social networking was the most personally relevant smartphone function were associated with smartphone addiction. Smartphone addiction was more prevalent in younger adolescents (15-16 years) compared with young adults (19 years and older), students with both parents born outside Switzerland, persons reporting lower physical activity, and those reporting higher stress. Alcohol and tobacco consumption were unrelated to smartphone addiction. DISCUSSION Different indicators of smartphone use are associated with smartphone addiction and subgroups of young people have a higher prevalence of smartphone addiction. CONCLUSIONS The study provides the first insights into smartphone use, smartphone addiction, and predictors of smartphone addiction in young people from a European country, which should be extended in further studies.
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review-article |
10 |
383 |
5
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Sharp DJ, Brown HM, Kwon M, Rogers GC, Holland G, Scholey JM. Functional coordination of three mitotic motors in Drosophila embryos. Mol Biol Cell 2000; 11:241-53. [PMID: 10637305 PMCID: PMC14771 DOI: 10.1091/mbc.11.1.241] [Citation(s) in RCA: 189] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
It is well established that multiple microtubule-based motors contribute to the formation and function of the mitotic spindle, but how the activities of these motors interrelate remains unclear. Here we visualize spindle formation in living Drosophila embryos to show that spindle pole movements are directed by a temporally coordinated balance of forces generated by three mitotic motors, cytoplasmic dynein, KLP61F, and Ncd. Specifically, our findings suggest that dynein acts to move the poles apart throughout mitosis and that this activity is augmented by KLP61F after the fenestration of the nuclear envelope, a process analogous to nuclear envelope breakdown, which occurs at the onset of prometaphase. Conversely, we find that Ncd generates forces that pull the poles together between interphase and metaphase, antagonizing the activity of both dynein and KLP61F and serving as a brake for spindle assembly. During anaphase, however, Ncd appears to have no effect on spindle pole movements, suggesting that its activity is down-regulated at this time, allowing dynein and KLP61F to drive spindle elongation during anaphase B.
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research-article |
25 |
189 |
6
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Kwon MJ, Lee J, Wark AW, Lee HJ. Nanoparticle-Enhanced Surface Plasmon Resonance Detection of Proteins at Attomolar Concentrations: Comparing Different Nanoparticle Shapes and Sizes. Anal Chem 2012; 84:1702-7. [DOI: 10.1021/ac202957h] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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13 |
135 |
7
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Brust-Mascher I, Civelekoglu-Scholey G, Kwon M, Mogilner A, Scholey JM. Model for anaphase B: role of three mitotic motors in a switch from poleward flux to spindle elongation. Proc Natl Acad Sci U S A 2004; 101:15938-43. [PMID: 15522967 PMCID: PMC524698 DOI: 10.1073/pnas.0407044101] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has been proposed that the suppression of poleward flux within interpolar microtubule (ipMT) bundles of Drosophila embryonic spindles couples outward forces generated by a sliding filament mechanism to anaphase spindle elongation. Here, we (i) propose a molecular mechanism in which the bipolar kinesin KLP61F persistently slides dynamically unstable ipMTs outward, the MT depolymerase KLP10A acts at the poles to convert ipMT sliding to flux, and the chromokinesin KLP3A inhibits the depolymerase to suppress flux, thereby coupling ipMT sliding to spindle elongation; (ii) used KLP3A inhibitors to interfere with the coupling process, which revealed an inverse linear relation between the rates of flux and elongation, supporting the proposed mechanism and demonstrating that the suppression of flux controls both the rate and onset of spindle elongation; and (iii) developed a mathematical model using force balance and rate equations to describe how motors sliding the highly dynamic ipMTs apart can drive spindle elongation at a steady rate determined by the extent of suppression of flux.
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Research Support, U.S. Gov't, P.H.S. |
21 |
112 |
8
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Burlat V, Kwon M, Davin LB, Lewis NG. Dirigent proteins and dirigent sites in lignifying tissues. PHYTOCHEMISTRY 2001; 57:883-97. [PMID: 11423139 DOI: 10.1016/s0031-9422(01)00117-0] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Tissue-specific dirigent protein gene expression and associated dirigent (site) localization were examined in various organs of Forsythia intermedia using tissue printing, in situ mRNA hybridization and immunolabeling techniques, respectively. Dirigent protein gene expression was primarily noted in the undifferentiated cambial regions of stem sections, whereas dirigent protein sites were detected mainly in the vascular cambium and ray parenchyma cell initials. Immunolocalization also revealed cross-reactivity with particular regions of the lignified cell walls, these being coincident with the known sites of initiation of lignin deposition. These latter regions are considered to harbor contiguous arrays of dirigent (monomer binding) sites for initiation of lignin biopolymer assembly. Dirigent protein mRNA expression was also localized in the vascular regions of roots and petioles, whereas in leaves the dirigent sites were primarily associated with the palisade layers and the vascular bundle. That is, dirigent protein mediated lignan biosynthesis was initiated primarily in the cambium and ray cell initial regions of stems as well as in the leaf palisade layers, this being in accordance with the occurrence of the lignans for defense purposes. Within lignified secondary xylem cell walls, however, dirigent sites were primarily localized in the S(1) sublayer and compound middle lamella, these being coincident with previously established sites for initiation of macromolecular lignin biosynthesis. Once initiation occurs, lignification is proposed to continue through template polymerization.
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24 |
108 |
9
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Hong SY, Oh JE, Kwon M, Choi MJ, Lee JH, Lee BL, Moon HM, Lee KH. Identification and characterization of novel antimicrobial decapeptides generated by combinatorial chemistry. Antimicrob Agents Chemother 1998; 42:2534-41. [PMID: 9756752 PMCID: PMC105883 DOI: 10.1128/aac.42.10.2534] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/1998] [Accepted: 07/15/1998] [Indexed: 11/20/2022] Open
Abstract
Novel combinatorial libraries consisting of simplified amino acid sequences were designed to screen for peptides active against the Candida albicans membrane. A novel decapeptide, KKVVFKVKFK, that had a unique primary amino acid sequence was identified in this work. This peptide irreversibly inhibited the growth of C. albicans and showed a broad range of antibacterial activity but no hemolytic activity. Circular dichroism spectra revealed that the predominant secondary structure of this peptide strongly depended on the membrane-mimetic environments; the peptide preferred to form an amphipathic alpha-helical structure in the presence of 50% trifluoroethanol, while it preferred to adopt a distorted alpha-helical structure in the presence of sodium dodecyl sulfate micelles. Experiments in which dye was released from vesicles indicated that this novel antimicrobial peptide killed microorganisms through the action on the membrane as its primary target. Replacement of amino acids in this active decapeptide on the basis of information from the libraries could provide unique information about factors affecting its antimicrobial activity such as its secondary structure, net positive charge, and hydrophobicity.
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research-article |
27 |
75 |
10
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Chung H, Kim TW, Kwon M, Kwon IC, Jeong SY. Oil components modulate physical characteristics and function of the natural oil emulsions as drug or gene delivery system. J Control Release 2001; 71:339-50. [PMID: 11295226 DOI: 10.1016/s0168-3659(00)00363-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Oil-in-water (o/w) type lipid emulsions were formulated by using 18 different natural oils and egg phosphatidylcholine (egg PC) to investigate how emulsion particle size and stability change with different oils. Cottonseed, linseed and evening primrose oils formed emulsions with very large and unstable particles. Squalene, light mineral oil and jojoba bean oil formed stable emulsions with small particles. The remaining natural oils formed moderately stable emulsions. Emulsions with smaller initial particle size were more stable than those with larger particles. The correlation between emulsion size made with different oils and two physical properties of the oils was also investigated. The o/w interfacial tension and particle size of the emulsion were inversely proportional. The effect of viscosity was less pronounced. To study how the oil component in the emulsion modulates the in vitro release characteristics of lipophilic drugs, three different emulsions loaded with two different drugs were prepared. Squalene, soybean oil and linseed oil emulsions represented the most, medium and the least stable systems, respectively. For the lipophilic drugs, release was the slowest from the most stable squalene emulsion, followed by soybean oil and then by linseed oil emulsions. Cationic emulsions were also prepared with the above three different oils as gene carriers. In vitro transfection activity was the highest for the most stable squalene emulsion followed by soybean oil and then by linseed oil emulsions. Even though the in vitro transfection activity of emulsions were lower than the liposome in the absence of serum, the activity of squalene emulsion, for instance, was ca. 30 times higher than that of liposome in the presence of 80% (v/v) serum. In conclusion, the choice of oil component in o/w emulsion is important in formulating emulsion-based drug or gene delivery systems.
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24 |
74 |
11
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Kim R, Kwon M, An M, Kim ST, Smith SA, Loembé AB, Mortimer PGS, Armenia J, Lukashchuk N, Shah N, Dean E, Park WY, Lee J. Phase II study of ceralasertib (AZD6738) in combination with durvalumab in patients with advanced/metastatic melanoma who have failed prior anti-PD-1 therapy. Ann Oncol 2021; 33:193-203. [PMID: 34710570 DOI: 10.1016/j.annonc.2021.10.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Modulating the DNA damage response and repair (DDR) pathways is a promising strategy for boosting cancer immunotherapy. Ceralasertib (AZD6738) is an oral inhibitor of the serine/threonine protein kinase ataxia telangiectasia and Rad3-related protein, which is crucial for DDR. PATIENTS AND METHODS This phase II trial evaluated ceralasertib plus durvalumab for the treatment of patients with metastatic melanoma who had failed anti-programmed cell death protein 1 therapy. RESULTS Among the 30 patients, we observed an overall response rate of 31.0% and a disease control rate of 63.3%. Responses were evident across patients with acral, mucosal, and cutaneous melanoma. The median duration of response was 8.8 months (range, 3.8-11.7 months). The median progression-free survival was 7.1 months (95% confidence interval, 3.6-10.6 months), and the median overall survival was 14.2 months (95% confidence interval, 9.3-19.1 months). Common adverse events were largely hematologic and manageable with dose interruptions and reductions. Exploratory biomarker analysis suggested that tumors with an immune-enriched microenvironment or alterations in the DDR pathway were more likely to respond to the study treatment. CONCLUSION We conclude that ceralasertib in combination with durvalumab has promising antitumor activity among patients with metastatic melanoma who have failed anti-programmed cell death protein 1 therapy, and constitute a population with unmet needs.
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4 |
67 |
12
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Kang HM, Choi KS, Kassam G, Fitzpatrick SL, Kwon M, Waisman DM. Role of annexin II tetramer in plasminogen activation. Trends Cardiovasc Med 1999; 9:92-102. [PMID: 10578524 DOI: 10.1016/s1050-1738(99)00012-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The enzymatic cascade triggered by activation of plasminogen has been implicated in a variety of normal and pathologic events, such as fibrinolysis, wound healing, tissue remodeling, embryogenesis, and the invasion and spread of transformed tumor cells. Recent data established that the Ca(2+)- and phospholipid-binding protein, annexin II heterotetramer (AIIt) binds tissue-type plasminogen activator (tPA), plasminogen, and plasmin, and dramatically stimulates the tPA-dependent conversion of plasminogen to plasmin in vitro. Interestingly, the binding of plasmin to AIIt can inhibit the activity of the enzyme, suggesting that plasmin bound to the cell surface is regulated by AIIt. The existing experimental evidence suggests that AIIt is the key physiological receptor for plasminogen on the extracellular surface of endothelial cells.
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Review |
26 |
54 |
13
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Lee JI, Kwon M, Roh JL, Choi JW, Choi SH, Nam SY, Kim SY. Postoperative hypoalbuminemia as a risk factor for surgical site infection after oral cancer surgery. Oral Dis 2014; 21:178-84. [PMID: 24605906 DOI: 10.1111/odi.12232] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 02/19/2014] [Accepted: 02/28/2014] [Indexed: 12/31/2022]
Abstract
OBJECTIVES Postoperative surgical site infection (SSI) is a frequent postoperative complication in patients with oral cancer and significantly affects patient recovery and medical expenses. The aim of this study was to examine the predictors of SSI in patients undergoing major surgery for oral or oropharyngeal squamous cell carcinoma (OSCC) and to determine the relationship between perioperative albumin and the development of SSI. SUBJECTS AND METHODS In 337 consecutive patients who underwent clean-contaminated surgery for OSCC, serum albumin, glucose, and hemoglobin levels were perioperatively measured. Differences between the groups were examined using Fisher's exact test, Mann-Whitney U-test, and multiple logistic regression analysis. RESULTS Surgical site infection was detected in 88 (26.1%) patients with median time to development of 10 (2-25) days. Multiple logistic regression analysis showed that only postoperative serum albumin < 2.5 g dl(-1) was an independent variable predictive of SSI (P = 0.003). The duration of hospital stay was negatively correlated with postoperative albumin (R(2) = -0.302, P < 0.001). CONCLUSION Early postoperative hypoalbuminemia <2.5 g dl(-1) is an independent risk factor for the development of SSI in patients undergoing oral cancer surgery. Clinicians should be aware of the implications of postoperative hypoalbuminemia and consider more intensive postoperative care in these patients.
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Research Support, Non-U.S. Gov't |
11 |
51 |
14
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Kwon MJ, Park S, Choi JY, Oh E, Kim YJ, Park YH, Cho EY, Kwon MJ, Nam SJ, Im YH, Shin YK, Choi YL. Clinical significance of CD151 overexpression in subtypes of invasive breast cancer. Br J Cancer 2012; 106:923-30. [PMID: 22294188 PMCID: PMC3306846 DOI: 10.1038/bjc.2012.11] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background: CD151 is a member of the tetraspanin family, which interacts with laminin-binding integrins and other tetraspanins. This protein is implicated in motility, invasion, and metastasis of cancer cells, but the prevalence of CD151 expression in subtypes of breast cancers and its influence on clinical outcome remains to be evaluated. Methods and results: The immunohistochemistry-based tissue microarray analysis showed that 127 (14.3%) cases overexpressed CD151 among 886 breast cancer patients. CD151 overexpression was found to be significantly associated with larger tumour size, higher nodal stage, advanced stage, absence of oestrogen receptor and progesterone receptor, and human epidermal growth factor receptor 2 overexpression. CD151 overexpression resulted in poorer overall survival (OS) (P<0.001) and disease-free survival (P=0.02), and stage II and III patients with CD151 overexpression demonstrated substantially poorer OS (P=0.0474 and 0.0169). In the five subtypes analyses, CD151 overexpression retained its adverse impact on OS in the Luminal A (P=0.0105) and quintuple-negative breast cancer (QNBC) subtypes, one subgroup of triple-negative breast cancer (P=0.0170). Multivariate analysis that included stage, subtype, and adjuvant chemotherapy showed that CD151 overexpression was independently associated with poor OS in invasive breast cancer. Conclusion: CD151 overexpression may be a potential molecular therapeutic target for breast cancer, especially in QNBC subtype and more advanced stages of breast cancer.
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Research Support, Non-U.S. Gov't |
13 |
51 |
15
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Cho H, Kwon M, Choi JH, Lee SK, Choi JS, Choi SW, Kim DJ. Development of the Internet addiction scale based on the Internet Gaming Disorder criteria suggested in DSM-5. Addict Behav 2014; 39:1361-6. [PMID: 24880884 DOI: 10.1016/j.addbeh.2014.01.020] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 01/15/2014] [Accepted: 01/29/2014] [Indexed: 10/25/2022]
Abstract
This study was conducted to develop and validate a standardized self-diagnostic Internet addiction (IA) scale based on the diagnosis criteria for Internet Gaming Disorder (IGD) in the Diagnostic and Statistical Manual of Mental Disorder, 5th edition (DSM-5). Items based on the IGD diagnosis criteria were developed using items of the previous Internet addiction scales. Data were collected from a community sample. The data were divided into two sets, and confirmatory factor analysis (CFA) was performed repeatedly. The model was modified after discussion with professionals based on the first CFA results, after which the second CFA was performed. The internal consistency reliability was generally good. The items that showed significantly low correlation values based on the item-total correlation of each factor were excluded. After the first CFA was performed, some factors and items were excluded. Seven factors and 26 items were prepared for the final model. The second CFA results showed good general factor loading, Squared Multiple Correlation (SMC) and model fit. The model fit of the final model was good, but some factors were very highly correlated. It is recommended that some of the factors be refined through further studies.
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Research Support, Non-U.S. Gov't |
11 |
50 |
16
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Lee KH, Hong SY, Oh JE, Kwon M, Yoon JH, Lee J, Lee BL, Moon HM. Identification and characterization of the antimicrobial peptide corresponding to C-terminal beta-sheet domain of tenecin 1, an antibacterial protein of larvae of Tenebrio molitor. Biochem J 1998; 334 ( Pt 1):99-105. [PMID: 9693108 PMCID: PMC1219667 DOI: 10.1042/bj3340099] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
An active fragment was identified from tenecin 1, an antibacterial protein belonging to the insect defensin family, by synthesizing the peptides corresponding to the three regions of tenecin 1. Only the fragment corresponding to the C-terminal beta-sheet domain showed activity against fungi as well as Gram-positive and Gram-negative bacteria, whereas tenecin 1, the native protein, showed activity only against Gram-positive bacteria. CD spectra indicated that each fragment in a membrane-mimetic environment might adopt a secondary structure corresponding to its region in the protein. The leakage of dye from liposomes induced by this fragment suggested that this fragment acts on the membrane of pathogens as a primary mode of action. A comparison between the structure and the activity of each fragment indicated that a net positive charge was a prerequisite factor for activity. To the best of our knowledge this is the first report in which the fragment corresponding to the beta-sheet region in antibacterial proteins, which consists of alpha-helical and beta-sheet regions, has been identified as a primary active fragment.
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research-article |
27 |
49 |
17
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Graham TM, Kwon M, Grinkemeyer B, Marra Z, Jiang X, Lichtman MT, Sun Y, Ebert M, Saffman M. Rydberg-Mediated Entanglement in a Two-Dimensional Neutral Atom Qubit Array. PHYSICAL REVIEW LETTERS 2019; 123:230501. [PMID: 31868460 DOI: 10.1103/physrevlett.123.230501] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Indexed: 06/10/2023]
Abstract
We demonstrate high fidelity two-qubit Rydberg blockade and entanglement on a pair of sites in a large two-dimensional qubit array. The qubit array is defined by a grid of blue detuned lines of light with 121 sites for trapping atomic qubits. Improved experimental methods have increased the observed Bell state fidelity to F_{Bell}=0.86(2). Accounting for errors in state preparation and measurement we infer a fidelity of F_{Bell}^{-SPAM}=0.88. Accounting for errors in single qubit operations we infer that a Bell state created with the Rydberg mediated C_{Z} gate has a fidelity of F_{Bell}^{C_{Z}}=0.89. Comparison with a detailed error model based on quantum process matrices indicates that finite atom temperature and laser noise are the dominant error sources contributing to the observed gate infidelity.
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6 |
48 |
18
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Schäpe P, Kwon MJ, Baumann B, Gutschmann B, Jung S, Lenz S, Nitsche B, Paege N, Schütze T, Cairns TC, Meyer V. Updating genome annotation for the microbial cell factory Aspergillus niger using gene co-expression networks. Nucleic Acids Res 2019; 47:559-569. [PMID: 30496528 PMCID: PMC6344863 DOI: 10.1093/nar/gky1183] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 11/27/2018] [Indexed: 12/11/2022] Open
Abstract
A significant challenge in our understanding of biological systems is the high number of genes with unknown function in many genomes. The fungal genus Aspergillus contains important pathogens of humans, model organisms, and microbial cell factories. Aspergillus niger is used to produce organic acids, proteins, and is a promising source of new bioactive secondary metabolites. Out of the 14,165 open reading frames predicted in the A. niger genome only 2% have been experimentally verified and over 6,000 are hypothetical. Here, we show that gene co-expression network analysis can be used to overcome this limitation. A meta-analysis of 155 transcriptomics experiments generated co-expression networks for 9,579 genes (∼65%) of the A. niger genome. By populating this dataset with over 1,200 gene functional experiments from the genus Aspergillus and performing gene ontology enrichment, we could infer biological processes for 9,263 of A. niger genes, including 2,970 hypothetical genes. Experimental validation of selected co-expression sub-networks uncovered four transcription factors involved in secondary metabolite synthesis, which were used to activate production of multiple natural products. This study constitutes a significant step towards systems-level understanding of A. niger, and the datasets can be used to fuel discoveries of model systems, fungal pathogens, and biotechnology.
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Research Support, Non-U.S. Gov't |
6 |
43 |
19
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Wexler ID, Du Y, Lisgaris MV, Mandal SK, Freytag SO, Yang BS, Liu TC, Kwon M, Patel MS, Kerr DS. Primary amino acid sequence and structure of human pyruvate carboxylase. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1227:46-52. [PMID: 7918683 DOI: 10.1016/0925-4439(94)90105-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Pyruvate carboxylase (PC) (pyruvate:carbon dioxide ligase (ADP-forming), EC 6.4.1.1.), a nuclear-encoded mitochondrial enzyme, catalyzes the conversion of pyruvate to oxaloacetate. We have isolated and characterized cDNAs spanning the entire coding region of human PC. The sequence of human PC has an open reading frame of 3537 nucleotides which encodes for a polypeptide with a length of 1178 amino acids. The identity of the cDNA as PC is confirmed by comparison to PC cDNAs of other species and sequenced peptide fragments of mammalian PC. The M(r) of the full length precursor protein is 129,576 and that of the mature apoprotein is 127,370. RNA blot analysis from a variety of human tissues demonstrates that the highest level of PC mRNA is found in liver corresponding to this tissue's high level of PC activity. Based on homology with other biotin-containing proteins, the ATP, pyruvate, and biotin-binding sites can be identified. One of two patients with documented PC deficiency was found to be missing PC mRNA, further confirming the identity of this cDNA.
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Comparative Study |
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Park J, Park C, Kwon M. Palladium Nanoparticles in Polymers: Catalyst for Alkene Hydrogenation, Carbon-Carbon Cross-Coupling Reactions, and Aerobic Alcohol Oxidation. SYNTHESIS-STUTTGART 2006. [DOI: 10.1055/s-2006-950329] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Kwon M, Roh JL, Song J, Lee SW, Kim SB, Choi SH, Nam SY, Kim SY. Noncancer health events as a leading cause of competing mortality in advanced head and neck cancer. Ann Oncol 2014; 25:1208-14. [PMID: 24669018 DOI: 10.1093/annonc/mdu128] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND The survival of patients with head and neck squamous cell carcinoma (HNSCC) can be affected by noncancer health events (NCHE) as well as by index cancer progression and second primary cancer (SPC). This study aimed to investigate the risk factors for NCHE and noncancer mortality (NCM) in patients with advanced-stage HNSCC. PATIENTS AND METHODS This cohort study involved 600 consecutive patients with overall stage III to IV HNSCC who were treated between 2001 and 2010 at our tertiary referral hospital. NCHE was defined as re-admission (i.e. after the primary treatments for the index tumors) due to noncancer-related causes. The incidences of NCHE and NCM and their risk factors were analyzed by using cumulative incidence and cause-specific hazard functions. RESULTS During a median follow-up period of 54 months, 224 (37.3%) and 55 (9.2%) of the 600 patients had NCHE and NCM, respectively. The 5-year index cancer mortality, SPC mortality, and NCM rates were 23.8%, 4.2%, and 8.9%, respectively. Multivariate analyses revealed that body mass index <20 kg/m(2) (P = 0.018), Charlson comorbidity index (CCI) ≥1 (P < 0.001), tumor recurrence (P < 0.001), SPC occurrence (P < 0.001), and initial chemotherapy (P = 0.049) were independent NCHE predictors. Older age (P < 0.001), CCI ≥1 (P = 0.008), tumor recurrence (P < 0.001), and SPC occurrence (P = 0.047) were independent NCM predictors. Patients with respiratory NCHE were at a higher risk of NCM than patients with other NCHE types (P < 0.001). CONCLUSIONS One or more comorbidities, tumor recurrence, and SPC occurrence were independent predictors of both NCHE and NCM. Patients with respiratory NCHE had a particularly high risk of NCM.
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Research Support, Non-U.S. Gov't |
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Ryu SY, Kwon MJ, Lee SB, Yang DW, Kim TW, Song IU, Yang PS, Kim HJ, Lee AY. Measurement of precuneal and hippocampal volumes using magnetic resonance volumetry in Alzheimer's disease. J Clin Neurol 2010; 6:196-203. [PMID: 21264200 PMCID: PMC3024524 DOI: 10.3988/jcn.2010.6.4.196] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 08/18/2010] [Accepted: 08/18/2010] [Indexed: 11/17/2022] Open
Abstract
Background and Purpose Alzheimer's disease (AD) is associated with structural alterations in the medial temporal lobe (MTL) and functional alterations in the posterior cortical region, especially in the early stages. However, it is unclear what mechanisms underlie these regional discrepancies or whether the posterior cortical hypometabolism reflects disconnection from the MTL lesion or is the result of local pathology. The precuneus, an area of the posteromedial cortex that is involved in the early stages of AD, has recently received a great deal of attention in functional neuroimaging studies. To assess the relationship between the precuneus and hippocampus in AD, we investigated the volumes of these two areas using a magnetic resonance volumetric method. Methods Twenty-three subjects with AD and 14 healthy age-matched controls underwent T1-weighted three-dimensional volumetric brain magnetic resonance imaging. Volumetric measurements were performed in the precuneus and hippocampus. Results Compared to controls, AD patients exhibited a significant reduction in total precuneal volume, which was more prominent on the right side, and significant bilateral reductions in hippocampal volume. No correlation was found between the total volumes of the precuneus and hippocampus in the AD group. Conclusions These results suggest that volumetric measurements of both the precuneus and hippocampus are useful radiological indices for the diagnosis of AD. Furthermore, the lack of correlation is attributable to local pathology rather than being a secondary consequence of MTL pathology.
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Journal Article |
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Kassam G, Kwon M, Yoon CS, Graham KS, Young MK, Gluck S, Waisman DM. Purification and characterization of A61. An angiostatin-like plasminogen fragment produced by plasmin autodigestion in the absence of sulfhydryl donors. J Biol Chem 2001; 276:8924-33. [PMID: 11114303 DOI: 10.1074/jbc.m009071200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plasmin, a broad spectrum proteinase, is inactivated by an autoproteolytic reaction that results in the destruction of the heavy and light chains of the protein. Recently we demonstrated that a 61-kDa plasmin fragment was one of the major products of this autoproteolytic reaction (Fitzpatrick, S. L., Kassam, G., Choi, K. S., Kang, H. M., Fogg, D. K., and Waisman, D. M. (2000)Biochemistry 39, 1021-1028). In the present communication we have identified the 61-kDa plasmin fragment as a novel four kringle-containing protein consisting of the amino acid sequence Lys(78)-Lys(468). To avoid confusion with the plasmin(ogen) fragment, angiostatin(R) (Lys(78)-Ala(440)), we have named this protein A(61). Unlike angiostatin, A(61) was produced in vitro from plasmin autodigestion in the absence of sulfhydryl donors. A(61) bound to lysine-Sepharose and also underwent a large increase in fluorescence yield upon binding of the lysine analogue, trans-4-aminomethylcyclohexanecarboxylic acid. Circular dichroism suggested that A(61) was composed of 21% beta-strand, 14% beta-turn, 18% 3(1)-helix and 8% 3(10)-helix. A(61) was an anti-angiogenic protein as indicated by the inhibition of bovine capillary endothelial cell proliferation. Plasminogen was converted to A(61) by HT1080 cells and bovine capillary endothelial cells. Furthermore, a plasminogen fragment similar to A(61) was present in the serum of humans as well as normal and tumor-bearing mice. These results establish that plasmin turnover can generate anti-angiogenic plasmin fragments in a nonpathological setting.
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Choi YL, Kim J, Kwon MJ, Choi JS, Kim TJ, Bae DS, Koh SS, In YH, Park YW, Kim SH, Ahn G, Shin YK. Expression profile of tight junction protein claudin 3 and claudin 4 in ovarian serous adenocarcinoma with prognostic correlation. Histol Histopathol 2007; 22:1185-95. [PMID: 17647191 DOI: 10.14670/hh-22.1185] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tight junction proteins claudin 3 (CLDN3) and claudin 4 (CLDN4) are frequently altered in several human cancers, including ovarian carcinomas. Here, we examined the gene expression of CLDN3 and CLDN4 in various tumors, including 19 normal ovaries and 47 ovarian carcinomas by analyzing Affymetrix HG-U133 array data. Furthermore, a total of 114 ovarian serous tumors, including 10 adenomas, 20 borderline tumors and 84 carcinomas, were analyzed immunohistochemically to confirm the expression of two proteins and we assessed the association of their expression with the clinicopathological characteristics and survival of the patients. The microarray experiment revealed CLDN3 and CLDN4 transcripts were significantly up-regulated by 5-fold or more in most subtypes of ovarian epithelial carcinomas while the immunohistochemical analyses indicated that each protein was expressed in 68 (81.0%) and 72 (85.7%) of 84 serous adenocarcinomas, respectively. Borderline serous tumors and adenomas showed significantly lower expression of these proteins than the adenocarcinomas. Kaplan-Meier survival analysis showed that serous adenocarcinoma patients with high CLDN3 expression had substantially shorter survival (P=0.027). Multivariate analysis demonstrated that CLDN3 overexpression is an independent negative prognostic factor. Our findings suggest that CLDN3 overexpression can be used as a prognostic indicator in ovarian serous carcinomas. Moreover, CLDN3 may be a promising target for antibody-based therapy of ovarian carcinomas.
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MESH Headings
- Biomarkers, Tumor/metabolism
- Claudin-3
- Claudin-4
- Cystadenocarcinoma, Serous/genetics
- Cystadenocarcinoma, Serous/metabolism
- Cystadenocarcinoma, Serous/mortality
- Cystadenocarcinoma, Serous/pathology
- Cystadenoma, Serous/genetics
- Cystadenoma, Serous/metabolism
- Cystadenoma, Serous/mortality
- Cystadenoma, Serous/pathology
- Female
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic
- Humans
- Male
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Ovarian Neoplasms/genetics
- Ovarian Neoplasms/metabolism
- Ovarian Neoplasms/mortality
- Ovarian Neoplasms/pathology
- Ovary/metabolism
- Ovary/pathology
- Prognosis
- RNA, Messenger/metabolism
- Retrospective Studies
- Survival Rate
- Tissue Array Analysis
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Research Support, Non-U.S. Gov't |
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Rho MH, Kim DW, Hong HP, Park YM, Kwon MJ, Jung SJ, Kim YW, Kang T. Diagnostic value of antithyroid peroxidase antibody for incidental autoimmune thyroiditis based on histopathologic results. Endocrine 2012; 42:647-52. [PMID: 22581205 DOI: 10.1007/s12020-012-9695-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 05/02/2012] [Indexed: 12/01/2022]
Abstract
Detection of antithyroid peroxidase antibody (TPOAb) is widely used in the diagnosis of autoimmune thyroiditis (AIT), but no research has evaluated the diagnostic accuracy of TPOAb detection using histopathologic reference standards. To fill this research gap, this study assessed the diagnostic accuracy of detection of TPOAb and that of other serological markers in asymptomatic patients who had been diagnosed with AIT by histopathologic analysis after thyroid surgery. After review of patient records, 598 patients who had undergone thyroid nodule surgery were enrolled for examination for thyroid parenchyma by a pathologist and classification into no co-existing lymphocytic thyroiditis, Hashimoto thyroiditis, or non-Hashimoto type of lymphocytic thyroiditis (NHLT). The correlation between patient serological data and thyroid parenchyma pathology was analyzed. Statistically significant differences (P < 0.05) were found between co-existing lymphocytic thyroiditis and no co-existing lymphocytic thyroiditis groups regarding thyroid-stimulating hormone (TSH) and TPOAb levels. And, TPOAb titer was significantly associated with the degree of inflammation. An abnormal TPOAb titer was found in 86 of the 598 patients (14.4 %) and the specificity of TPOAb detection for AIT diagnosis was found to be 96.9 %. The prevalence of Hashimoto thyroiditis and NHLT in the 560 papillary thyroid cancer (PTC) patients was found to be 7.9 and 17.9 %, respectively. The results indicate that TPOAb titer is associated with the degree of thyroid inflammation and that detection of TPOAb is a very specific means of diagnosing AIT. The results also indicate that the incidence of AIT and PTC coexistence is relatively high.
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MESH Headings
- Adult
- Aged
- Analysis of Variance
- Antibodies
- Carcinoma, Papillary, Follicular/diagnosis
- Carcinoma, Papillary, Follicular/immunology
- Carcinoma, Papillary, Follicular/surgery
- Female
- Hashimoto Disease/blood
- Hashimoto Disease/diagnosis
- Humans
- Immunoassay
- Iodide Peroxidase/immunology
- Male
- Middle Aged
- Thyroidectomy
- Thyroiditis, Autoimmune/blood
- Thyroiditis, Autoimmune/diagnosis
- Thyroiditis, Autoimmune/immunology
- Thyroiditis, Autoimmune/surgery
- Thyrotropin/blood
- Thyroxine/blood
- Triiodothyronine/blood
- Young Adult
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