57 results on '"Kim, Kun Woo"'
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2. Preparing water-resistant films using partially debranched potato starch and oleic acid.
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Kim KW, Lee YJ, and Park EY
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Improvement in film-forming properties of starch is critical for the wide application of environmentally friendly starch film. To enhance moisture barrier and mechanical properties of starch films, the formation of starch-lipid inclusion complex was promoted by partial debranching of starch and reaction at various temperature. The partially debranched potato starch was initially prepared with pullulanase, and the starch-lipid inclusion complex was subsequently produced with oleic acid at various reaction temperatures of 30, 50, and 70 °C. The partial debranching combined with oleic acid addition induced characteristic V-type crystalline peaks in the X-ray diffraction (XRD) patterns. The highest reaction temperature, of 70 °C, induced more apparent XRD peaks and higher thermal transition temperatures and enthalpy. The partially debranched starch film with oleic acid at 70 °C showed a smooth and uniform surface with a more rigid and condensed network. The high content of starch-lipid inclusion complexes in a partially debranched starch film with oleic acid at 70 °C significantly reduced water vapor permeability (from 162.22 to 65.99 g∙mm∙m
-2 ∙day-1 ∙atm-1 ) and increased both the contact angle (from 61.08 to 74.55°) and tensile strength (from 2.126 to 5.473 MPa) compared to a native starch film. Therefore, the formation of more abundant starch-lipid inclusion complexes at relatively high reaction temperatures with partial debranched starch can effectively enhance the moisture barrier properties of starch films for industrial application as biodegradable film., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)- Published
- 2024
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3. Thermoelectric Transport Driven by the Hilbert-Schmidt Distance.
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Oh CG, Kim KW, and Rhim JW
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The geometric characteristics of Bloch wavefunctions play crucial roles in the properties of electronic transport. Within the Boltzmann equation framework, we demonstrate that the thermoelectric performance of materials is significantly influenced by the Hilbert-Schmidt distance of Bloch wavefunctions. The connection between the distribution of quantum distance on the Fermi surface and the electronic transport scattering rate is established in the presence of magnetic and nonmagnetic impurities. The general formulation is applied to isotropic quadratic band-touching semimetals, where one can concentrate on the role of quantum geometric effects other than the Berry curvature. It is verified that the thermoelectric power factor can be succinctly expressed in terms of the maximum quantum distance, d
max . Specifically, when dmax reaches one, the power factor doubles compared to the case with trivial geometry (dmax = 0). These findings highlight the significance of quantum geometry in understanding and improving the performance of thermoelectric devices., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)- Published
- 2024
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4. Feasibility of Home-Based Pulmonary Rehabilitation of Pediatric Patients with Chronic Respiratory Diseases.
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Kim DY, Mo YH, Kim KW, Hong SM, Park A, Jang BH, Lee SH, Lee JH, Yoon J, Yu J, and Ko EJ
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Background and Objective: Chronic respiratory diseases in children deteriorate their daily life due to dyspnea and reduced lung function. We aimed to evaluate the feasibility of home-based pulmonary rehabilitation in pediatric chronic respiratory diseases., Methods: This prospective, single-arm, cohort study included children with chronic lung disease. They were instructed to perform home-based pulmonary rehabilitation 30 min/session, three sessions/week for three months. Pulmonary function test (PFT) using spirometry, respiratory muscle strength (RMT), cardiopulmonary exercise test (CPET), 6 min walk test (6MWT), dyspnea questionnaires, speech evaluation, and pediatric quality of life inventory (PedsQL) were assessed pre- and post-pulmonary rehabilitation. Compliance and satisfaction of the program were also evaluated., Results: Twenty children (mean age: 11.2 ± 3.1 years) with chronic respiratory diseases without cardiopulmonary instability participated. The overall compliance was 71.1% with no related adverse events. After pulmonary rehabilitation, forced expiratory volume in one second (FEV
1 ), peak expiratory flow (PEF), RMT, 6MWT, dyspnea questionnaire, speech rate, and PedsQL (child) significantly improved ( p < 0.05), particularly better in the FEV1 < 60% group than in the FEV1 ≥ 60% group and in the high-compliance group (compliance ≥ 50%) than in the low-compliance group (compliance < 50%)., Conclusions: Home-based pulmonary rehabilitation for children with chronic lung disease was feasible with high compliance and effective in terms of objective functions, subjective dyspnea symptom, and quality of life.- Published
- 2024
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5. 3D-Printed Auxetic Skin Scaffold for Decreasing Burn Wound Contractures at Joints.
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Park JK, Kim KW, Kim HJ, Choi SY, Son KH, and Lee JW
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For patients with severe burns that consist of contractures induced by fibrous scar tissue formation, a graft must adhere completely to the wound bed to enable wound healing and neovascularization. However, currently available grafts are insufficient for scar suppression owing to their nonuniform pressure distribution in the wound area. Therefore, considering the characteristics of human skin, which is omnidirectionally stretched via uniaxial stretching, we proposed an auxetic skin scaffold with a negative Poisson's ratio (NPR) for tight adherence to the skin scaffold on the wound bed site. Briefly, a skin scaffold with the NPR effect was fabricated by creating a fine pattern through 3D printing. Electrospun layers were also added to improve adhesion to the wound bed. Fabricated skin scaffolds displayed NPR characteristics (-0.5 to -0.1) based on pulling simulation and experiment. Finger bending motion tests verified the decreased marginal forces (<50%) and deformation (<60%) of the NPR scaffold. In addition, the filling of human dermal fibroblasts in most areas (>95%) of the scaffold comprising rarely dead cells and their spindle-shaped morphologies revealed the high cytocompatibility of the developed scaffold. Overall, the developed skin scaffold may help reduce wound strictures in the joints of patients with burns as it exerts less pressure on the wound margin.
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- 2023
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6. Cost-effectiveness of physical activity interventions for prevention and management of cognitive decline and dementia-a systematic review.
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Li W, Kim KR, Zhang D, Liu B, Dengler-Crish CM, Wen M, Shi L, Pan X, Gu Y, and Li Y
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- Humans, Cost-Benefit Analysis, Cognition, Exercise, Cognitive Dysfunction prevention & control, Dementia prevention & control
- Abstract
Background: Although increasing physical activity (PA) has been suggested to prevent and manage cognitive decline and dementia, its economic impact on healthcare systems and society is largely unknown. This study aimed to summarize evidence on the cost-effectiveness of PA interventions to prevent and manage cognitive decline and dementia., Methods: Electronic databases, including PubMed/MEDLINE, Embase, and ScienceDirect, were searched from January 2000 to July 2023. The search strategy was driven by a combination of subject-heading terms related to physical activity, cognitive function, dementia, and cost-effectiveness. Selected studies were included in narrative synthesis, and extracted data were presented in narrative and tabular forms. The risk of bias in each study was assessed using the Consolidated Health Economic Evaluation Reporting Standards and Consensus on Health Economic Criteria list., Results: Five of the 11 identified studies focused on individuals with existing dementia. Six of the 11 identified studies focused on individuals with no existing dementia, including 3 on those with mild cognitive impairment (MCI), and 3 on those with no existing MCI or dementia. PA interventions focused on individuals with no existing dementia were found to be cost-effective compared to the control group. Findings were mixed for PA interventions implemented in individuals with existing dementia., Conclusions: PA interventions implemented before or during the early stage of cognitive impairment may be cost-effective in reducing the burden of dementia. More research is needed to investigate the cost-effectiveness of PA interventions in managing dementia. Most existing studies used short-term outcomes in evaluating the cost-effectiveness of PA interventions in the prevention and management of dementia; future research should consider adding long-term outcomes to strengthen the study design., (© 2023. BioMed Central Ltd., part of Springer Nature.)
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- 2023
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7. Novel Strategy To Inhibit Transthyretin Amyloidosis via the Synergetic Effect of Chemoselective Acylation and Noncovalent Inhibitor Release.
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Lee SB, Yu J, Kim H, Kim KW, Jeong JW, Kim YL, Park SJ, Koo TS, Lee C, Hong KB, and Choi S
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- Humans, Models, Molecular, Binding Sites, Drug Discovery, Prealbumin metabolism, Amyloid Neuropathies, Familial drug therapy
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Strategies for developing targeted covalent inhibitors (TCIs), which have the advantages of a prolonged duration of action and selectivity toward a drug target, have attracted great interest in drug discovery. Herein, we report chemoselective covalent inhibitors that specifically target lysine ε-amine groups that conjugate with an endogenous protein to prevent disease-causing protein misfolding and aggregation. These TCIs are unique because the benzoyl group is preferentially conjugated to Lys15 at the top of the T
4 binding site within transthyretin (TTR) while simultaneously releasing a potent noncovalent TTR kinetic stabilizer. The potency of these covalent inhibitors is superior to tafamidis, the only FDA-approved drug for the treatment of hereditary TTR amyloidosis. In addition to investigations into the covalent modification of TTR via reverse-phase high-performance liquid chromatography, direct methods are performed to confirm and visualize the presumed covalent interaction via mass spectrometry and X-ray crystallography.- Published
- 2023
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8. Facet Connectivity-Based Estimation Algorithm for Manufacturability of Supportless Parts Fabricated via LPBF.
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Lee SY, Lee JW, Yang MS, Kim DH, Jung HG, Ko DC, and Kim KW
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Recent advances in additive manufacturing have provided more freedom in the design of metal parts; hence, the prototyping of fluid machines featuring extremely complex geometries has been investigated extensively. The fabrication of fluid machines via additive manufacturing requires significant attention to part stability; however, studies that predict regions with a high risk of collapse are few. Therefore, a novel algorithm that can detect collapse regions precisely is proposed herein. The algorithm reflects the support span over the faceted surface via propagation and invalidates overestimated collapse regions based on the overhang angle. A heat exchanger model with an extremely complex internal space is adopted to validate the algorithm. Three samples from the model are extracted and their prototypes are fabricated via laser powder bed fusion. The results yielded by the fabricated samples and algorithm with respect to the sample domain are compared. Regions of visible collapse identified on the surface of the fabricated samples are predicted precisely by the algorithm. Thus, the supporting span reflected by the algorithm provides an extremely precise prediction of collapse.
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- 2023
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9. Absolute Bed Rest Duration of 3 Days for Osteoporotic Vertebral Fractures: A Retrospective Study.
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Cho ST, Kim SJ, Nam BJ, Kim KW, Lee GH, and Kim JH
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Study Design: Retrospective case-control study., Purpose: To reduce unnecessary absolute bed rest (ABR), this study sought to determine the optimal aimed length of ABR in older patients getting conservative treatment for osteoporotic vertebral fractures (OVFs)., Overview of Literature: OVFs are quite common in elderly patients. ABR is a vital part of conservative treatment for OVFs, although the length of ABR may increase patient. No recommendations regarding how long ABR should last., Methods: This study was conducted in 134 patients with OVFs initially treated conservatively. The patients were split into two groups: 3-day and 7-day ABR. From the time of injury to 1, 4, and 12 weeks after injury, compression rate (CR) and local kyphotic angle (LKA) were assessed and compared between the two groups. Any complications such as pneumonia, deep vein thrombosis, delirium, and urinary tract infection known to be related to ABR were examined based on the electronic medical record., Results: Forty-four patients underwent ABR for 3 days and 90 underwent ABR for 7 days. There was no significant difference in CR and LKA between the two groups at the time of injury versus 1, 4, and 12 weeks after injury. The patients were divided into two groups: those who received a 3-day ABR and those who received a 7-day ABR. CR and LKA were measured and compared between the two groups from the time of damage to 1, 4, and 12 weeks after injury. The ABR-related complication rate was 43.4% in the 7-day ABR group and 22.7% in 3-day ABR group (p=0.02). The duration of hospital stay was significantly shorter in the 3-day ABR group (12.8 days) than in the 7-day group (16 days) (p=0.01)., Conclusions: Considering radiological outcomes, prognosis, complications, patient convenience, and economic impact, a 3-day ABR period is appropriate for the conservative treatment of OVFs.
- Published
- 2022
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10. Tumour-infiltrating bystander CD8 + T cells activated by IL-15 contribute to tumour control in non-small cell lung cancer.
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Leem G, Jeon M, Kim KW, Jeong S, Choi SJ, Lee YJ, Kim ES, Lee JI, Ha SY, Park SH, Shim HS, Lee JG, Kang SM, and Shin EC
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- Animals, CD8-Positive T-Lymphocytes metabolism, CD8-Positive T-Lymphocytes pathology, Humans, Interferon-gamma metabolism, Interleukin-15 metabolism, Interleukin-15 pharmacology, Mice, NK Cell Lectin-Like Receptor Subfamily K metabolism, Tumor Microenvironment, Carcinoma, Non-Small-Cell Lung pathology, Lung Neoplasms pathology
- Abstract
Background: Tumour-unrelated, virus-specific bystander CD8
+ T cells were recently shown to be abundant among tumour-infiltrating lymphocytes (TILs). However, their roles in tumour immunity have not been elucidated yet., Methods: We studied the characteristics of bystander CD8+ TILs from non-small cell lung cancer (NSCLC) tissues (N=66) and their activation by interleukin (IL)-15 to repurpose them for tumour immunotherapy., Results: We show that bystander CD8+ TILs specific to various viruses are present in human NSCLC tissues. We stimulated CD8+ TILs ex vivo using IL-15 without cognate antigens and found that IL-15 treatment upregulated NKG2D expression on CD8+ TILs, resulting in NKG2D-dependent production of interferon (IFN)-γ (p=0.0006). Finally, we tested whether IL-15 treatment can control tumour growth in a murine NSCLC model with or without a history of murine cytomegalovirus (MCMV) infection. IL-15 treatment reduced the number of tumour nodules in the lung only in mice with MCMV infection (p=0.0037). We confirmed that MCMV-specific bystander CD8+ TILs produced interferon (IFN)-γ after IL-15 treatment, and that IL-15 treatment in MCMV-infected mice upregulated tumour necrosis factor-α and IFN-γ responsive genes in tumour microenvironment., Conclusion: Thus, the study demonstrates that bystander CD8+ TILs can be repurposed by IL-15 for tumour immunotherapy., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)- Published
- 2022
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11. Hydrophilic guidewire usage under ultrasound guidance in facilitating catheter advancement during endovenous treatment of incompetent great saphenous veins.
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Hwang K, Park SW, Hwang JH, Kwon YW, Min J, Jang H, Chang IS, and Kim KW
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Purpose: This study was performed To investigate the use of hydrophilic guidewires for facilitating catheter advancement during varicose vein treatment using radiofrequency ablation (RFA) or cyanoacrylate closure (CAC)., Methods: From March 2016 to April 2019, 463 limbs of 285 with incompetent great saphenous veins were subjected to RFA (321 limbs of 197 patients) or CAC (142 limbs of 88 patients). Procedure records were reviewed for the use of a hydrophilic guidewire, reason for the guidewire usage, and diameter of the guidewire., Results: A hydrophilic guidewire was used to facilitate catheter advancement to treat 92 of 463 limbs (19.9%). For RFA, a guidewire was used to treat 53 of 321 limbs (16.5%). Among them, 15 limbs (28.3%) had vasospasm, and 38 limbs (71.7%) had venous tortuosity. For CAC, guidewire was used for 39 of 142 limbs (27.5%). Among them, 10 limbs (25.6%) had vasospasm, 23 limbs (59.0%) had venous tortuosity, and 6 limbs (15.4%) had repeated engagement of a J-tip guidewire into the varicose tributaries. In CAC, the frequency of hydrophilic guidewire usage was higher than that in RFA (P = 0.006). All varicose vein treatment sessions were technically successful., Conclusion: Hydrophilic guidewire usage could facilitate catheter advancement when hindered by vasospasm, tortuosity of the saphenous vein, or repeated engagement into the varicose tributaries., Competing Interests: Conflicts of Interest: Although a grant was from Terumo Research Fund through the Korean Society of Interventional Radiology, the funder has no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. No potential conflict of interest relevant to this article was reported., (Copyright © 2022, the Korean Surgical Society.)
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- 2022
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12. A Study on the Mechanical Properties of an Automobile Part Additively Printed through Periodic Layer Rotation Strategies.
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Yang MS, Kang JH, Kim JW, Kim KW, Kim DH, Sung JH, Ko DC, and Lee JW
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In metal product manufacturing, additive manufacturing (AM) is a method that has the advantage of fabricating complex shapes and customized production, unlike existing machining methods. However, owing to the characteristics of the AM process, anisotropy of macrostructure occurs because of various causes such as the scan direction, melting, fusion, and cooling of the powdered material. The macrostructure anisotropy is realized from the scan direction, and when a single layer is stacked in one direction, it is expressed as orthogonal anisotropy. Here, the classical lamination theory is applied to simply calculate the individual orthotropic layers by superimposing them. Through this, the authors analyzed whether the mechanical properties of the product are isotropically expressed with a periodic layer rotation strategy. To determine if the mechanical properties can be reasonably considered to be isotropic, a shock absorber mount for a vehicle was manufactured by AM. The tensile and vibration test performed on the product was compared with the finite element analysis and experimental results. As a result of the comparison, it was confirmed that the macroscopically of the product was considered isotropic as the load-displacement diagram and the fracture location coincided, as well as the natural frequency and mode shape.
- Published
- 2021
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13. The impact of fine particulate matter (PM) on various beneficial functions of human endometrial stem cells through its key regulator SERPINB2.
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Park SR, Lee JW, Kim SK, Yu WJ, Lee SJ, Kim D, Kim KW, Jung JW, and Hong IS
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- Apoptosis, Biomarkers, Computational Biology methods, Energy Metabolism, Female, Gene Expression Profiling, Gene Expression Regulation, Glycolysis, Humans, Intracellular Signaling Peptides and Proteins metabolism, Oxidative Phosphorylation, Signal Transduction, Endometrium cytology, Endometrium metabolism, Intracellular Signaling Peptides and Proteins genetics, Particulate Matter, Stem Cells cytology, Stem Cells metabolism
- Abstract
Fine particulate matter (PM) has a small diameter but a large surface area; thus, it may have broad toxic effects that subsequently damage many tissues of the human body. Interestingly, many studies have suggested that the recent decline in female fertility could be associated with increased PM exposure. However, the precise mechanisms underlying the negative effects of PM exposure on female fertility are still a matter of debate. A previous study demonstrated that resident stem cell deficiency limits the cyclic regenerative capacity of the endometrium and subsequently increases the pregnancy failure rate. Therefore, we hypothesized that PM exposure induces endometrial tissue damage and subsequently reduces the pregnancy rate by inhibiting various beneficial functions of local endometrial stem cells. Consistent with our hypothesis, we showed for the first time that PM exposure significantly inhibits various beneficial functions of endometrial stem cells, such as their self-renewal, transdifferentiation, and migratory capacities, in vitro and in vivo through the PM target gene SERPINB2, which has recently been shown to be involved in multiple stem cell functions. In addition, the PM-induced inhibitory effects on the beneficial functions of endometrial stem cells were significantly diminished by SERPINB2 depletion. Our findings may facilitate the development of promising therapeutic strategies for improving reproductive outcomes in infertile women., (© 2021. The Author(s).)
- Published
- 2021
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14. Detection of Lateral Hinge Fractures After Medial Closing Wedge Distal Femoral Osteotomy: Computed Tomography Versus Plain Radiography.
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Nha KW, Kim KW, Bae JH, Jang KM, and Kim SG
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- Adult, Cohort Studies, Humans, Middle Aged, Osteotomy adverse effects, Radiography, Retrospective Studies, Tomography, X-Ray Computed, Young Adult, Osteoarthritis, Knee diagnostic imaging, Tibia
- Abstract
Background: Limited evidence exists in the literature regarding the detection rates of lateral hinge fracture (LHF) on computed tomography (CT) after medial closing wedge distal femoral osteotomy (MCDFO). Moreover, the effect of LHF on bone healing after MCDFO remains unclear., Hypothesis: The detection rates of LHF after MCDFO would be higher on CT than on plain radiography. The incidence of problematic bone healing would be higher in the knees with LHF than in those without LHF., Study Design: Cohort study (diagnosis), Level of evidence, 3., Methods: Patients who underwent MCDFO between May 2009 and July 2019 were retrospectively evaluated. The presence of LHF was evaluated using immediate postoperative plain radiography and CT. The detection rates of LHF on plain radiography and CT were compared. The incidence of problematic bone healing (nonunion, delayed union, and loss of correction) was also compared between the knees with LHF and those without LHF., Results: A total of 55 knees of 43 patients (mean age, 37.7 ± 16.7 years) were included in the study. Although 33 LHFs were detected on CT, only 19 LHFs were detected on plain radiography. The detection rate of LHF was significantly higher on CT than on plain radiography (60% vs 34.5%; P = .008). At 1-year follow-up, 10 cases of problematic bone healing (1 nonunion, 4 delayed unions, and 5 losses of correction) were identified. The incidence of problematic bone healing was significantly higher in the knees with LHF than in those without LHF as shown on plain radiography (36.8% vs 8.3%; P = .001) and CT (30.3% vs 0%; P = .004)., Conclusion: LHF can be detected better on CT than on plain radiography and has a negative effect on bone healing after MCDFO. For patients with LHF detected on either plain radiography or CT, careful rehabilitation with close follow-up is recommended.
- Published
- 2021
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15. Noncanonical functions of glucocorticoids: A novel role for glucocorticoids in performing multiple beneficial functions in endometrial stem cells.
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Park SR, Kim SK, Kim SR, Kim D, Kim KW, Hong IS, and Lee HY
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- Animals, Cells, Cultured, Endometrium cytology, Endometrium metabolism, Female, Fertility drug effects, Fertility physiology, Humans, MAP Kinase Signaling System drug effects, Mice, Receptors, Glucocorticoid metabolism, Regeneration drug effects, Regeneration physiology, Stem Cells physiology, Endometrium drug effects, Glucocorticoids pharmacology, Stem Cells drug effects
- Abstract
Chronic stress has a negative impact on many fertility-related functions; thus, the recent decline in female fertility seems to be at least partially associated with increased stress. The secretion of glucocorticoids is a typical endocrine response to chronic stress and indirectly reduces uterine receptivity through the hypothalamus-pituitary-gonadal (HPG) axis. However, in addition to its well-known canonical role, the direct effects of chronic stress-induced glucocorticoids on various uterine functions and their underlying molecular mechanisms are complex and have not yet been revealed. Recent studies have found that resident stem cell deficiency is responsible for the limited regenerative potential of the endometrium (the innermost lining of the uterine cavity) during each menstrual cycle, which subsequently increases infertility rates. In this context, we hypothesized that stress-induced glucocorticoids directly damage endometrial stem cells and consequently negatively affect endometrial reconstruction, which is important for uterine receptivity. In addition to its well-known canonical roles, we identified for the first time that cortisol, the most abundant and potent glucocorticoid in humans, directly suppresses the multiple beneficial functions (self-renewal, transdifferentiation, and migratory potential) of human endometrial stem cells through its functional receptor, glucocorticoid receptor (GR). Glucocorticoids inhibit well-known survival signals, such as the PI3K/Akt and FAK/ERK1/2 pathways. More importantly, we also found that immobilization of stress-induced glucocorticoids suppresses the various beneficial functions of tissue resident stem cells in vivo. To the best of our knowledge, this is the first study to investigate the direct effects of glucocorticoids on the regenerative capacity of endometrial stem cells, and the findings will facilitate the development of more promising therapeutic approaches to increase female fertility.
- Published
- 2021
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16. Deterioration of mitochondrial function in the human intercostal muscles differs among individuals with sarcopenia, obesity, and sarcopenic obesity.
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Kim KW, Baek MO, Yoon MS, and Son KH
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- Adult, Aged, Aged, 80 and over, Cytokines genetics, Cytokines metabolism, Female, Gene Expression Regulation, Humans, Inflammation metabolism, Inflammation pathology, Male, Middle Aged, Muscle, Skeletal metabolism, Obesity metabolism, RNA, Messenger genetics, RNA, Messenger metabolism, Sarcopenia metabolism, Mitochondria, Muscle pathology, Obesity pathology, Sarcopenia pathology
- Abstract
Background & Aims: Sarcopenic obesity (SO) increases the risk of mortality more than sarcopenia or obesity alone. Sarcopenia weakens the peripheral and respiratory muscles, leading to respiratory complications. It also induces mitochondrial dysfunction in the peripheral muscle; however, whether mitochondrial dysfunction in respiratory muscles differs among individuals with obesity, sarcopenia, and SO remains unknown. We evaluated the deterioration of respiratory muscle strength and mitochondrial function among normal, sarcopenia, obesity, and SO subjects., Methods: Twenty-five patients who underwent lung resections were enrolled between April 2017 and January 2021, and their intercostal muscles were harvested. Based on their L3 muscle index and visceral fat area, the patients were divided into four groups (normal, obesity, sarcopenia, and SO). The clinical data, mRNA expression, and protein expressions associated with mitochondrial biogenesis/fusion/fission in the intercostal muscles were compared among the four groups., Results: The respiratory muscle strength was evaluated using peak expiratory flow rate (PEFR). The PEFR values of the four groups were not significantly different. The levels of pAkt/Akt and mTOR (a marker of protein synthesis) were not significantly different among the four groups; however, those in the SO group were substantially lower than those in the sarcopenia or obesity groups. The levels of Atrogen-1 and MuRF1 (a marker of protein degradation) were not significantly different among the four groups; however, those in the SO group were substantially higher than those in the sarcopenia or obesity groups. Expression of PGC1-α (a marker of mitochondrial biogenesis) in the SO group was significantly lower than that in the normal group. MFN1 and MFN2 (marker of mitochondrial fusion) levels were significantly lower in the SO group than those in the normal group. DRP1 (a marker of mitochondrial fission) level in the SO group was substantially lower than that in the normal group. The expression of TNF-α (a pro-inflammatory cytokine) in the SO group was substantially lower than that in the normal group., Conclusion: Our results suggest that the deterioration of protein synthesis and degradation of mitochondrial function in the respiratory muscles was most prominent in the SO before the weakening of the respiratory muscles. The deterioration mechanism may differentially regulate obesity, sarcopenia, and SO., Competing Interests: Conflict of interest The authors declare no conflict of interest., (Copyright © 2021 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)
- Published
- 2021
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17. Prognostic significance of radiodensity-based skeletal muscle quantification using preoperative CT in resected non-small cell lung cancer.
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Kim EY, Kim YJ, Kim YS, Kim KW, Jeon JY, and Kim KG
- Abstract
Background: Sarcopenia is associated with poor prognosis in lung cancer. Skeletal muscle area can be quantified based on radiodensity of CT scan. The purpose of this study was to evaluate the prognostic significance of radiodensity-based detailed skeletal muscle quantification on outcomes after surgery of non-small cell lung cancer (NSCLC)., Methods: Single cross-sectional area of the skeletal muscle (-29 to 150 HU) at the 3rd lumbar vertebra (L3) level retrospectively measured on preoperative CT for NSCLC patients (n=272), who underwent surgical resection during 2011 to 2016. The diagnosis of sarcopenia was made when a L3 muscle index (L3MI; L3 muscle area/height2) of less than 55 cm
2 /m2 for men and less than 39 cm2 /m2 for women. Skeletal muscle was subsequently classified based on radiodensity level as low attenuation muscle (-29 to <30 HU) and high attenuation muscle (30 to 150 HU). Using a maximal-chi-squared test, low attenuation muscle accounted less than 24.5% of the total muscle, which was considered healthy muscle. Data on clinical characteristics (demographic information, TNM stage, histology) and prognosis (disease-free survival; DFS, and overall survival; OS) were collected., Results: Sarcopenia was found 22.4% in preoperative CT (32.9% for men and 6.5% for women). The prevalence of patients with healthy muscle was 15.4% (21.3% for men and 6.5% for women). There was no significant difference between the 3-year DFS rate (77.0% vs. 67.0%, P=0.142) or 3-year OS rate (84.8% vs. 87.9%, P=0.576) between patients with and without sarcopenia. However, patients with healthy muscle tend to show longer 3-year DFS rate (79.4% vs. 67.2%, P=0.094) and 3-year OS rate (92.6% vs. 86.1%, P=0.176). In the multivariable analysis, healthy muscle was one of the independent prognosticators for a 3-year DFS rate (HR, 0.50, P=0.035), along with R1 resection (HR, 5.90, P<0.001), pathologic T stage (HR, 2.69, P<0.001), and pathologic N stage (HR, 2.43, P<0.001)., Conclusions: The proportion of low attenuation muscle was associated with DFS in resected lung cancer patients. Further investigation is needed to establish whether radiodensity-based detailed skeletal muscle quantification could be early biomarker to predict prognosis in NSCLC., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/jtd-20-2344). The authors have no conflicts of interest to declare., (2021 Journal of Thoracic Disease. All rights reserved.)- Published
- 2021
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18. Synthesis and Structure of Multinuclear Pd(II) Complexes Bridged by Phosphide or Azide Ligands.
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Takeuchi K, Kim KW, Kim YJ, Fukaya N, Sato K, and Choi JC
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The synthesis and structure of phosphide- and azide-bridged multinuclear Pd(II) complexes bearing phosphine ligands [PdX(μ-X')(PR
3 )]n (X = Cl and N3 ; X' = PR2 ' and N3 ; n = 2 and 4) are reported. The oxidative addition of R2 ' PCl to Pd(PMe3 )2 furnished the phosphide-bridged dinuclear Pd(II) complexes [PdCl(μ-PR2 ' )(PMe3 )]2 [R' =i Pr ( 1a ) and Cy ( 1b )]. However, the oxidative addition of ( o -tolyl)2 PCl to Pd(PMe3 )2 produced a nonbridged mononuclear Pd(II) complex with the bis( o -tolyl)phosphinic ligand, trans -[Pd(PMe3 )2 {P(O)( o -tolyl)2 }] ( 2 ), via oxidation of the phosphinyl ligand. The reaction of the chloride-bridged dinuclear Pd(II) complexes [PdCl(μ-Cl)(PR3 )]2 [PR3 = PEt3 ( 3a ) and PPhMe2 ( 3b )] with NaN3 afforded the azide-bridged dinuclear and tetranuclear Pd(II) complexes [Pd(N3 )(μ-N3 )(PEt3 )]2 ( 4 ) and [Pd(N3 )(μ-N3 )(PPhMe2 )]4 ( 5 ). Comparisons of the X-ray structures of 4 and 5 show that the square-planar molecular geometry of the Pd(II) centers of 4 are more distorted than those of 5 . Density functional theory calculations suggest that the tetranuclear eight-membered ring structure like 5 is more stable than the dinuclear four-membered ring structure like 4 in the gas phase in both PEt3 and PPhMe2 systems. However, because the relative energy difference between the four-membered and eight-membered ring structures is small in the PEt3 system with smaller steric hindrance compared with PPhMe2 , it is assumed that this difference is compensated by the crystal packing energy, and the dinuclear four-membered ring complex 4 is actually obtained., Competing Interests: The authors declare no competing financial interest., (© 2020 American Chemical Society.)- Published
- 2020
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19. Low Tibial Valgization Osteotomy for More Severe Varus Ankle Arthritis.
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Choi JY, Kim KW, and Suh JS
- Subjects
- Activities of Daily Living, Aged, Female, Humans, Male, Middle Aged, Plastic Surgery Procedures methods, Retrospective Studies, Surveys and Questionnaires, Ankle Joint surgery, Osteoarthritis surgery, Osteotomy methods
- Abstract
Background: Low tibial valgization osteotomy with medial opening wedge (LTO) is generally indicated for ankle arthritis with a small talar tilt (TT). We addressed the following research questions: the efficacy of LTO for more significant varus ankle arthritis, the effect of additional inframalleolar correction followed by LTO, and the preoperative or operation-related factors influencing postoperative TT decrease., Methods: We retrospectively reviewed the radiographic and clinical findings of 31 patients with more significant varus ankle arthritis (≥8 degrees) who underwent LTO or LTO plus inframalleolar correction. We grouped the included patients according to combination with inframalleolar correction and postoperative decreased TT. Furthermore, a binary logistic regression analysis was performed to determine the factors influencing postoperative TT decrease., Results: Even though the mean TT was unchanged postoperatively (from 12.1 to 9.9 degrees, P = .052), clinical parameters were significantly increased. In the group with concomitant inframalleolar correction, we found that TT was more corrected (3.9 vs 1.8 degrees, P = .023) with a greater lateralization of the talar center and a greater correction of the hindfoot alignment to valgus. The results of the binary logistic regression analysis showed a significant relationship between postoperative decreased TT and preoperative talar center migration ( P = .016), hindfoot alignment angle ( P = .033), hindfoot moment arm ( P = .041), and hindfoot alignment ratio ( P = .016)., Conclusion: LTO in more significant varus ankle arthritis could result in clinical improvement, although TT was not significantly changed. We recommend adding inframalleolar correction after LTO for the patients with more significant varus ankle arthritis., Level of Evidence: Level III, comparative series.
- Published
- 2020
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20. Comparative Analyses of mTOR/Akt and Muscle Atrophy-Related Signaling in Aged Respiratory and Gastrocnemius Muscles.
- Author
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Kim KW, Cho HJ, Khaliq SA, Son KH, and Yoon MS
- Subjects
- Animals, Autophagy genetics, Biomarkers, Disease Models, Animal, Gene Expression, Intercostal Muscles metabolism, Mitochondria, Muscle genetics, Mitochondria, Muscle metabolism, Muscular Atrophy genetics, Muscular Atrophy pathology, Rats, Respiratory Muscles metabolism, Ubiquitin genetics, Ubiquitin metabolism, Aging metabolism, Muscle, Skeletal metabolism, Muscular Atrophy metabolism, Proto-Oncogene Proteins c-akt metabolism, Signal Transduction, TOR Serine-Threonine Kinases metabolism
- Abstract
Sarcopenia is the degenerative loss of skeletal muscle mass and function associated with aging and occurs in the absence of any underlying disease or condition. A comparison of the age-related molecular signaling signatures of different muscles has not previously been reported. In this study, we compared the age-related molecular signaling signatures of the intercostal muscles, the diaphragm, and the gastrocnemii using 6-month and 20-month-old rats. The phosphorylation of Akt, ribosomal S6, and Forkhead box protein O1 (FoxO1) in diaphragms significantly increased with age, but remained unchanged in the intercostal and gastrocnemius muscles. In addition, ubiquitin-proteasome degradation, characterized by the levels of MuRF1 and Atrogin-1, did not change with age in all rat muscles. Interestingly, an increase in LC3BII and p62 levels marked substantial blockage of autophagy in aged gastrocnemii but not in aged respiratory muscles. These changes in LC3BII and p62 levels were also associated with a decrease in markers of mitochondrial quality control. Therefore, our results suggest that the age-related signaling events in respiratory muscles differ from those in the gastrocnemii, most likely to preserve the vital functions played by the respiratory muscles.
- Published
- 2020
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21. Optical spin-orbit torque in heavy metal-ferromagnet heterostructures.
- Author
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Choi GM, Oh JH, Lee DK, Lee SW, Kim KW, Lim M, Min BC, Lee KJ, and Lee HW
- Abstract
Spin current generation through the spin-orbit interaction in non-magnetic materials lies at the heart of spintronics. When the generated spin current is injected to a ferromagnet, it produces spin-orbit torque and manipulates magnetization efficiently. Optically generated spin currents are expected to be superior to their electrical counterparts in terms of the manipulation speed. Here we report optical spin-orbit torques in heavy metal/ferromagnet heterostructures. The strong spin-orbit coupling of heavy metals induces photo-excited carriers to be spin-polarized, and their transport from heavy metals to ferromagnets induces a torque on magnetization. Our results demonstrate that heavy metals can generate spin-orbit torque not only electrically but also optically.
- Published
- 2020
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22. Analysis of the Molecular Signaling Signatures of Muscle Protein Wasting Between the Intercostal Muscles and the Gastrocnemius Muscles in db/db Mice.
- Author
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Kim KW, Baek MO, Choi JY, Son KH, and Yoon MS
- Subjects
- Animals, Diabetes Complications genetics, Diabetes Complications pathology, Diabetes Mellitus, Experimental genetics, Diabetes Mellitus, Experimental pathology, Diabetes Mellitus, Type 2 genetics, Diabetes Mellitus, Type 2 pathology, Male, Mechanistic Target of Rapamycin Complex 1 genetics, Mechanistic Target of Rapamycin Complex 1 metabolism, Mice, Mice, Transgenic, Muscle Proteins genetics, Muscle, Skeletal pathology, Muscular Atrophy genetics, Muscular Atrophy pathology, Diabetes Complications metabolism, Diabetes Mellitus, Experimental metabolism, Diabetes Mellitus, Type 2 metabolism, Muscle Proteins metabolism, Muscle, Skeletal metabolism, Muscular Atrophy metabolism, Signal Transduction
- Abstract
Type 2 diabetes (T2D) patients suffer from dyspnea, which contributes to disease-related morbidity. Although T2D has been reported to induce a catabolic state in skeletal muscle, whether T2D induces muscle wasting in respiratory muscles has not yet been investigated. In this study, we examine the difference in the molecular signaling signature of muscle wasting between the intercostal and gastrocnemius muscles using db/db mice, a well-known diabetic mouse model. Akt phosphorylation was significantly decreased in both the intercostal and gastrocnemius muscles of db/db mice and was accompanied by a decrease in mTORC1 activity. In addition, FoxO phosphorylation was suppressed, and ubiquitin-proteasome degradation, characterized by the level of Atrogin-1 and MuRF1, was subsequently enhanced in both muscle types of db/db mice. An increase in LC3BII levels and a decrease in p62 levels marked the occurrence of substantial autophagy in the gastrocnemius muscle but not in the intercostal muscles of db/db mice. Therefore, we suggest that the signaling events of muscle wasting in the intercostal muscles of db/db mice are different from those in the gastrocnemius muscle of db/db mice.
- Published
- 2019
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23. Fate of spontaneous pneumothorax from middle to old age: how to overcome an irritating recurrence?
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Nam SH, Kim KW, Kim SW, Kim SW, Hong JM, and Kim D
- Abstract
Background: The causes and treatment of pneumothorax in older patients are different from those in younger patients. However, studies on this topic are limited thus; pneumothorax in older patients is often inadequately managed. The purpose of this research was to investigate the characteristics of pneumothorax in patients over 45 years old, understand patterns of management and factors of recurrence, and propose reasonable guidelines for the treatment of older patients., Methods: Of 438 consecutive patients with spontaneous pneumothorax between 2013 and 2017, 120 patients were enrolled and divided into two groups: (I) 45-64 years and (II) ≥65 years. Basic demographics, treatment modality, and patterns of surgery/recurrence were described. Clinical variables were compared between groups, and risk factors of recurrence were analyzed using logistic regression., Results: The study population was divided into group A (younger, n=61) and B (older, n=59). Chest tube drainage was the most common procedure for both groups and chemical pleurodesis was applied more often in B (27% vs. 11%, P=0.03). The length of hospital stay was longer in B (8.8 vs. 5.9 days, P<0.01) but complications and recurrence rate did not differ between groups (P=0.09 and 0.93). The choice of procedures in recurrent pneumothorax was different (P=0.02). Specifically, invasive procedures such as surgery occurred more often in A, but non-invasive procedures occurred more often in B. Multivariate analysis revealed that bullae/blebs (odds ratio=5.57) and emphysema (odds ratio=3.83) showed a positive association with recurrence whereas surgery (odds ratio=0.11) was negative., Conclusions: Radiological findings of emphysema or bullae/blebs are risk factors for recurrence of pneumothorax in elderly patients. Surgery in selected patients is an effective method for decreasing the recurrence rate., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare., (2019 Journal of Thoracic Disease. All rights reserved.)
- Published
- 2019
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24. Nanomechanical characterization of quantum interference in a topological insulator nanowire.
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Kim M, Kim J, Hou Y, Yu D, Doh YJ, Kim B, Kim KW, and Suh J
- Abstract
Aharonov-Bohm conductance oscillations emerge as a result of gapless surface states in topological insulator nanowires. This quantum interference accompanies a change in the number of transverse one-dimensional modes in transport, and the density of states of such nanowires is also expected to show Aharonov-Bohm oscillations. Here, we demonstrate a novel characterization of topological phase in Bi
2 Se3 nanowire via nanomechanical resonance measurements. The nanowire is configured as an electromechanical resonator such that its mechanical vibration is associated with its quantum capacitance. In this way, the number of one-dimensional transverse modes is reflected in the resonant frequency, thereby revealing Aharonov-Bohm oscillations. Simultaneous measurements of DC conductance and mechanical resonant frequency shifts show the expected oscillations, and our model based on the gapless Dirac fermion with impurity scattering explains the observed quantum oscillations successfully. Our results suggest that the nanomechanical technique would be applicable to a variety of Dirac materials.- Published
- 2019
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25. Experimental realization of on-chip topological nanoelectromechanical metamaterials.
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Cha J, Kim KW, and Daraio C
- Abstract
Guiding waves through a stable physical channel is essential for reliable information transport. However, energy transport in high-frequency mechanical systems, such as in signal-processing applications
1 , is particularly sensitive to defects and sharp turns because of back-scattering and losses2 . Topological phenomena in condensed matter systems have shown immunity to defects and unidirectional energy propagation3 . Topological mechanical metamaterials translate these properties into classical systems for efficient phononic energy transport. Acoustic and mechanical topological metamaterials have so far been realized only in large-scale systems, such as arrays of pendulums4 , gyroscopic lattices5,6 , structured plates7,8 and arrays of rods, cans and other structures acting as acoustic scatterers9-12 . To fulfil their potential in device applications, mechanical topological systems need to be scaled to the on-chip level for high-frequency transport13-15 . Here we report the experimental realization of topological nanoelectromechanical metamaterials, consisting of two-dimensional arrays of free-standing silicon nitride nanomembranes that operate at high frequencies (10-20 megahertz). We experimentally demonstrate the presence of edge states, and characterize their localization and Dirac-cone-like frequency dispersion. Our topological waveguides are also robust to waveguide distortions and pseudospin-dependent transport. The on-chip integrated acoustic components realized here could be used in unidirectional waveguides and compact delay lines for high-frequency signal-processing applications.- Published
- 2018
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26. Isolated Unilateral Absence of Pulmonary Artery Associated with Contralateral Lung Cancer.
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Kim KW, Lee JI, Son KH, Kim EY, Park KY, and Park CH
- Abstract
Unilateral absence of a pulmonary artery (UAPA) is a rare congenital anomaly that may present with various symptoms, depending on the nature and severity of other cardiovascular anomalies. Furthermore, contralateral lung surgery in patients with UAPA is extremely rare, and clinical experience is limited. This report describes a case of surgical treatment of contralateral primary lung cancer in a patient with isolated UAPA. A 56-year-old man was diagnosed with primary lung cancer accompanied by isolated UAPA on the contralateral side. He underwent meticulous cardiorespiratory function tests preoperatively. We performed a right lower lobectomy. Although in the immediate postoperative period, the patient suffered from a mild decline in his respiratory function, he recovered uneventfully. The present case shows that preoperative awareness of UAPA and meticulous perioperative management enable contralateral lung surgery to be performed safely., Competing Interests: Conflict of interest No potential conflict of interest relevant to this article was reported.
- Published
- 2018
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27. Does Smoking Confound Risk Factor of Video-Assisted Thoracoscopic Lobectomy 90-Day Mortality?
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Kim KW, Lee JI, and Son KH
- Subjects
- Incidence, Risk Factors, Smoking, Pneumonectomy, Thoracic Surgery, Video-Assisted
- Published
- 2018
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28. Histologic subtypes are not associated with the presence of sarcopenia in lung cancer.
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Kim CR, Kim EY, Kim YS, Ahn HK, Kim KW, Jeong YM, and Kim JH
- Subjects
- Adenocarcinoma complications, Aged, Body Mass Index, Carcinoma, Squamous Cell complications, Comorbidity, Female, Humans, Lung Neoplasms complications, Male, Prevalence, Prognosis, Republic of Korea epidemiology, Retrospective Studies, Sarcopenia epidemiology, Small Cell Lung Carcinoma complications, Tomography, X-Ray Computed, Adenocarcinoma pathology, Carcinoma, Squamous Cell pathology, Lung Neoplasms pathology, Sarcopenia pathology, Small Cell Lung Carcinoma pathology
- Abstract
Background: Sarcopenia is prevalent and a known adverse prognostic effector in lung cancer (LCA). However, the relationship between sarcopenia and histology remains uncertain in LCA., Methods: Consecutive patients with newly diagnosed LCA (n = 778) between June 2012 and February 2015 were retrospectively reviewed to identify factors associated with sarcopenia. Sarcopenia was defined as CT-determined L3 muscle index (muscle area at L3/height2) of < 55 cm2/m2 for men and < 39 cm2/m2 for women., Results: Mean patient age was 67.7 ± 10.8 years, and most (73.1%) were male. The most prevalent histology was adenocarcinoma (44.0%) and 71.6% of patients had stage III or IV disease. The overall prevalence of sarcopenia was 48.2% (60.3% in men, and 15.3% in women). Univariable analysis showed sarcopenia was significantly associated with male gender, age (≥ 65 years), smoking status, lower BMI (< 23 kg/m2), advanced stage (III and IV), and high comorbidity score (Charlson index ≥ 3). Furthermore, the prevalence of sarcopenia was higher in squamous cell carcinoma (54.9%) and small cell LCA (56.4%) than in adenocarcinoma (39.8%). Multivariable analyses showed sarcopenia was independently associated with a male gender (odds ratio [OR], 11.13), elderly (OR, 2.02) and low BMI (OR, 6.28), stage IV (OR, 1.98), and high comorbidity (OR, 1.93). However, no significant association was found between histologic subtypes and sarcopenia., Conclusions: Sarcopenia was found to be significantly associated with old age, male gender, an advanced stage, comorbidities, and low BMI in LCA. However, histology subtype was not an independent factor for the presence of sarcopenia.
- Published
- 2018
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29. Prediction of Vestibular Imbalance in Acute Peripheral Vestibulopathy by Measuring Horizontal Ocular Deviation on Magnetic Resonance Imaging.
- Author
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Yang YJ, Kim KW, Choi JE, Lee MY, Yoo DS, and Jung JY
- Subjects
- Adult, Female, Humans, Male, Middle Aged, Retrospective Studies, Vertigo diagnostic imaging, Vertigo etiology, Vestibular Function Tests methods, Vestibular Neuronitis complications, Eye diagnostic imaging, Magnetic Resonance Imaging methods, Vestibular Neuronitis diagnostic imaging
- Abstract
Objectives: The aim of the study is to evaluate whether horizontal ocular deviation (OD) from MR imaging in the emergency room (ER) reflects vestibular imbalance, by comparing the horizontal OD in patients with acute vestibulopathy to controls., Study Design: Retrospective review., Patients and Methods: A total of 69 patients with acute unilateral peripheral vestibulopathy and 30 healthy subjects were included. Horizontal OD was quantified by using the axial T2-weighted fast-spin echo (FSE) images of the brain at 1.5 T. In the study group, the results of VFTs (videonystagmography [VNG], caloric test, rotary chair test, and cervical vestibular evoked myogenic potentials [cVEMP]) were also reviewed. The averaged angle of right and left horizontal ODs was compared between patients with acute unilateral vestibulopathy and healthy controls. Also, the correlation between horizontal OD and results of VFTs was analyzed in the study group., Results: The averaged angle of horizontal OD in study group (23.7° ± 11.6°) was significantly greater than that of control group (4.27° ± 3.7°) (p < 0.05). Horizontal OD significantly correlated with slow phase velocity of spontaneous nystagmus (SN), the value of caloric paresis (CP) on caloric testing, rotary chair gain, asymmetry ratio of rotary chair test and interaural difference (IAD) of cVEMP, regardless of time intervals between magnetic resonance imaging (MRI) and VFTs., Conclusions: Horizontal OD significantly correlated with parameters of VFT which reflect the vestibular imbalance. Therefore, horizontal OD can be used as an indicator of unilateral peripheral vestibular weakness.
- Published
- 2018
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30. Esophageal Endoscopic Vacuum Therapy with Enteral Feeding Using a Sengstaken-Blakemore Tube.
- Author
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Lee SY, Kim KW, Lee JI, Park DK, Park KY, Park CH, and Son KH
- Abstract
Early diagnosis followed by primary repair is the best treatment for spontaneous esophageal perforation. However, the appropriate management of esophageal leakage after surgical repair is still controversial. Recently, the successful adaptation of vacuum-assisted closure therapy, which is well established for the treatment of chronic surface wounds, has been demonstrated for esophageal perforation or leakage. Conservative treatment methods require long-term fasting with total parenteral nutrition or enteral feeding through invasive procedures, such as percutaneous endoscopic gastrostomy or a feeding jejunostomy. We report 2 cases of esophageal leakage after primary repair treated by endoscopic vacuum therapy with continuous enteral feeding using a Sengstaken-Blakemore tube., Competing Interests: Conflict of interest No potential conflict of interest relevant to this article was reported.
- Published
- 2018
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31. Mastoid Vibration Reduces Ipsilesional Shift of Subjective Visual Horizontal in Patients with Acute Stage of Unilateral Vestibulopathy.
- Author
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Kim KW, Lee MY, and Jung JY
- Abstract
Background and Objectives: To investigate effect of the vibration on subjective visual horizontal (SVH) in patients with acute stage of unilateral vestibulopathy., Subjects and Methods: Twenty-five unilateral vestibulopathy patients which analyzed into 42 cases at different time points and suffered from spinning vertigo for more than 24 hours without hearing loss and neurologic abnormality were enrolled. Thirteen subjects with spontaneous nystagmus (>3 degree/sec; averaged symptom onset <1 week) at the time of SVH measurement were classified into the acute unilateral vestibulopathy group (aVU). The other 29 subjects without spontaneous nystagmus were classified into the compensated vestibulopathy group (cVU). SVH was performed with vibration at either mastoid or sterocleidomastoid muscle., Results: In the analysis of overall subjects, vibration did not significantly change the degree of shift of SVH. However, analyzed by group, the shift of SVH with vibration at ipsilesional mastoid was significantly decreased than baseline in aVU ( p <0.05). The shift of SVH with vibration at contralesional mastoid was significantly increased than baseline in cVU ( p =0.05)., Conclusions: The shift of SVH due to vibration in acute stage of unilateral vestibulopathy showed reduction of the shift, while in compensated stage it showed increase of the shift.
- Published
- 2017
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32. Outcomes of Curative-Intent Surgery and Adjuvant Treatment for Pulmonary Large Cell Neuroendocrine Carcinoma.
- Author
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Kim KW, Kim HK, Kim J, Shim YM, Ahn MJ, and Choi YL
- Subjects
- Adult, Aged, Aged, 80 and over, Carcinoma, Neuroendocrine mortality, Carcinoma, Neuroendocrine pathology, Carcinoma, Non-Small-Cell Lung mortality, Carcinoma, Non-Small-Cell Lung pathology, Chemotherapy, Adjuvant, Female, Humans, Male, Middle Aged, Pneumonectomy, Retrospective Studies, Treatment Outcome, Carcinoma, Neuroendocrine therapy, Carcinoma, Non-Small-Cell Lung therapy, Lung Neoplasms therapy
- Abstract
Background: Pulmonary large cell neuroendocrine carcinoma (LCNEC) is pathologically classified as non-small-cell lung cancer (NSCLC), but its clinical behavior is more aggressive than other types of NSCLC. Accordingly, the optimal treatment strategy for LCNEC, including the indication of adjuvant treatment, remains controversial., Methods: A retrospective review of 139 patients who underwent curative-intent surgery for LCNEC was performed to investigate clinicopathologic features and survival outcomes and to evaluate whether adjuvant treatment affected survival outcomes., Results: The mean patient age was 64 years (126 men, 90.6%). Operative procedures included 111 lobectomies (79.8%), 12 pneumonectomies (8.6%), and 2 sublobar resections. Pathologic stage was IA in 31 (22%), IB in 36 (26%), IIA in 34 (24%), IIB in 9 (6%), IIIA in 19 (14%), IIIB in 2 (1.4%), and IV in 4 patients (2.9%). Postoperatively, 50 patients (36%) received adjuvant treatment. The median follow-up duration was 33 months. The 5-year overall survival (OS) rate was 53%, and 5-year disease-free survival (DFS) rate was 39%. In patients with pathologic stage I, there was no significant difference in either OS or DFS according to the addition of adjuvant treatment. However, in patients with pathologic stage II or higher, patients who underwent adjuvant treatment showed significantly better OS (p = 0.023) and DFS (p = 0.038)., Conclusions: Our findings showed that patients who underwent curative-intent surgery for LCNEC benefitted from the use of adjuvant treatment especially in pathologic stage II or higher.
- Published
- 2017
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33. Quantum Phase Transition and Entanglement in Topological Quantum Wires.
- Author
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Cho J and Kim KW
- Abstract
We investigate the quantum phase transition of the Su-Schrieffer-Heeger (SSH) model by inspecting the two-site entanglements in the ground state. It is shown that the topological phase transition of the SSH model is signified by a nonanalyticity of local entanglement, which becomes discontinuous for finite even system sizes, and that this nonanalyticity has a topological origin. Such a peculiar singularity has a universal nature in one-dimensional topological phase transitions of noninteracting fermions. We make this clearer by pointing out that an analogous quantity in the Kitaev chain exhibiting the identical nonanalyticity is the local electron density. As a byproduct, we show that there exists a different type of phase transition, whereby the pattern of the two-site entanglements undergoes a sudden change. This transition is characterised solely by quantum information theory and does not accompany the closure of the spectral gap. We analyse the scaling behaviours of the entanglement in the vicinities of the transition points.
- Published
- 2017
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34. Surface to bulk Fermi arcs via Weyl nodes as topological defects.
- Author
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Kim KW, Lee WR, Kim YB, and Park K
- Abstract
A hallmark of Weyl semimetal is the existence of surface Fermi arcs. An intriguing question is what determines the connectivity of surface Fermi arcs, when multiple pairs of Weyl nodes are present. To answer this question, we show that the locations of surface Fermi arcs are predominantly determined by the condition that the Zak phase integrated along the normal-to-surface direction is . The Zak phase can reveal the peculiar topological structure of Weyl semimetal directly in the bulk. Here, we show that the winding of the Zak phase around each projected Weyl node manifests itself as a topological defect of the Wannier-Stark ladder, energy eigenstates under an electric field. Remarkably, this leads to bulk Fermi arcs, open-line segments in the bulk spectra. Bulk Fermi arcs should exist in conjunction with surface counterparts to conserve the Weyl fermion number under an electric field, which is supported by explicit numerical evidence.
- Published
- 2016
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35. A Korean Multi-Center Survey about Warfarin Management before Gastroenterological Endoscopy in Patients with a History of Mechanical Valve Replacement Surgery.
- Author
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Son KH, Choi CH, Lee JI, Kim KW, Kim JS, Lee SY, Park KY, and Park CH
- Abstract
Background: Guidelines for esophagogastroduodenoscopy (EGD) in the West allow the continued use of warfarin under therapeutic international normalized ratio (INR) level. In Korea, no guidelines have been issued regarding warfarin treatment before EGD. The authors surveyed Korean cardiac surgeons about how Korean cardiac surgeons handle warfarin therapy before EGD using a questionnaire. Participants were requested to make decisions regarding the continuation of warfarin therapy in two hypothetical cases., Methods: The questionnaire was administered to cardiac surgeons and consisted of eight questions, including two case scenarios., Results: Thirty-six cardiac surgeons at 28 hospitals participated in the survey, and 52.7% of the participants chose to stop warfarin before EGD in aortic valve replacement patients without risk factors for thromboembolism. When the patient's INR level was 2, 31% of the participants indicated that they would choose to continue warfarin therapy. For EGD with biopsy, 72.2% of the participants chose warfarin withdrawal, and 25% of the participants chose heparin replacement. In mitral valve replacement patients, 47.2% of the participants chose to discontinue warfarin, and 22.2% of the participants chose heparin replacement. For EGD with biopsy in patients with a mitral valve replacement, 58.3% of the participants chose to stop warfarin, and 41.7% of the participants chose heparin replacement., Conclusion: This study demonstrated that attitudes regarding warfarin treatment for EGD are very different among Korean surgeons. Guidelines specific to the Korean population are required.
- Published
- 2016
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36. Surgical Planning by 3D Printing for Primary Cardiac Schwannoma Resection.
- Author
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Son KH, Kim KW, Ahn CB, Choi CH, Park KY, Park CH, Lee JI, and Jeon YB
- Subjects
- Adult, Atrial Septum pathology, Atrial Septum surgery, Cardiomegaly diagnostic imaging, Female, Heart Atria pathology, Heart Neoplasms pathology, Humans, Magnetic Resonance Imaging, Cine, Neurilemmoma surgery, Radiography, Sternotomy, Treatment Outcome, Vena Cava, Superior pathology, Cardiomegaly etiology, Cardiopulmonary Bypass, Heart Neoplasms surgery, Neurilemmoma pathology, Printing, Three-Dimensional
- Abstract
We report herein a case of benign cardiac schwannoma in the interatrial septum. A 42-year-old woman was transferred from a clinic because of cardiomegaly as determined by chest X-ray. A transthoracic echocardiography and chest computed tomography examination revealed a huge mass in the pericardium compressing the right atrium, superior vena cava (SVC), left atrium, and superior pulmonary vein. To confirm that the tumor originated from either heart or mediastinum, cine magnetic resonance imaging was performed, but the result was not conclusive. To facilitate surgical planning, we used 3D printing. Using a printed heart model, we decided that tumor resection under cardiopulmonary bypass (CPB) through sternotomy would be technically feasible. At surgery, a huge tumor in the interatrial septum was confirmed. By incision on the atrial roof between the aorta and SVC, tumor enucleation was performed successfully under CPB. Pathology revealed benign schwannoma. The patient was discharged without complication. 3D printing of the heart and tumor was found to be helpful when deciding optimal surgical approach.
- Published
- 2015
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37. Bronchial Artery Aneurysm Presenting as Hematemesis and Mediastinal Hemorrhage.
- Author
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Kim JS, Lee SY, Son KH, Kim KW, Choi CH, Lee JI, Park KY, and Park CH
- Abstract
Hematemesis is a rare manifestation of a ruptured bronchial artery aneurysm (BAA) in the mediastinum. It is difficult to diagnose a ruptured BAA presenting as hematemesis, because it can be confused with other diseases, such as Boerhaave's syndrome, variceal disease, or a perforated ulcer. In this report, we describe a case of BAA resulting in hematemesis and mediastinal hemorrhage.
- Published
- 2015
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38. Risk factors for urinary retention following minor thoracic surgery.
- Author
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Kim KW, Lee JI, Kim JS, Lee YJ, Choi WJ, Jung H, Park KY, Park CH, and Son KH
- Subjects
- Adult, Age Factors, Comorbidity, Decision Support Techniques, Diabetes Mellitus epidemiology, Female, Humans, Incidence, Male, Pneumonectomy adverse effects, Republic of Korea epidemiology, Retrospective Studies, Risk Assessment, Risk Factors, Sex Factors, Thoracic Surgery, Video-Assisted adverse effects, Treatment Outcome, Urinary Retention diagnosis, Thoracic Surgical Procedures adverse effects, Urinary Retention epidemiology
- Abstract
Objectives: Our goals were (i) to identify the incidence and risk factors of postoperative urinary retention in minor thoracic surgery patients and (ii) to develop a scoring system to predict postoperative urinary retention in these patients., Methods: Two hundred and ninety-two consecutive patients who underwent thoracic surgery without a pre- or intraoperative indwelling urinary catheter under general anaesthesia were used to identify the risk factors of postoperative urinary retention (post-void residual urine >200 ml) and to develop the scoring system predicting the incidence of this complication. We investigated past history, type of operation, operation time, amount of administered intravenous fluids, medications used perioperatively as well as demographic data., Results: The incidence rate of postoperative urinary retention was 11.6% (34/292). Independent risk factors and their scores were the following: age above 40 years (P < 0.001; two points); male (P = 0.002; one point); diabetes mellitus (P = 0.002; one point) and lung resection (P < 0.001; two points). The cut-off value for a model predicting postoperative urinary retention was five points (C-index = 0.88; 95% confidence interval: 0.83-0.94), with 73% sensitivity and 90% specificity., Conclusions: In minor thoracic surgery patients, special attention should be paid to detect postoperative urinary retention in those with the following characteristics: age over 40 years, male gender, history of diabetes mellitus and candidates for lung resection. The use of the developed scoring system may help in identifying those high-risk patients who need more aggressive management to prevent bladder overdistension and associated urinary complications., (© The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2015
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39. A rare presentation of catamenial hemoptysis as a solitary pulmonary nodule.
- Author
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Kim KW, Lee JI, Kim EY, Kim H, Lee SH, Kang SM, Kim YS, and Kim JH
- Subjects
- Adult, Diagnosis, Differential, Endometriosis surgery, Female, Hemoptysis surgery, Humans, Radiography, Thoracic, Solitary Pulmonary Nodule surgery, Thoracic Surgery, Video-Assisted, Tomography, X-Ray Computed, Endometriosis diagnostic imaging, Hemoptysis diagnostic imaging, Solitary Pulmonary Nodule diagnostic imaging
- Abstract
Thoracic endometriosis is a rare disorder characterized by the presence of functioning endometrial tissue within the pleura, lung parenchyma, or the airways. We report a case of catamenial hemoptysis with a rare presentation, that is, as a solitary pulmonary nodule with an internal cavity and surrounding ground glass opacity.
- Published
- 2015
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40. Proper compression landmark and depth for cardiopulmonary resuscitation in patients with pectus excavatum: a study using CT.
- Author
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Lee KH, Kim KW, Kim EY, Kim HS, Kim JH, Cho J, and Yang HJ
- Subjects
- Adolescent, Adult, Female, Humans, Male, Middle Aged, Anatomic Landmarks, Cardiopulmonary Resuscitation methods, Funnel Chest diagnostic imaging, Heart Massage methods, Tomography, X-Ray Computed
- Abstract
Objective: To determine by chest CT the proper compression landmark and depth for cardiopulmonary resuscitation in patients with pectus excavatum (PE)., Methods: The chest CT of 22 patients with PE (mean age=27 years; range 16-53 years, 10 male) from March 2002 to September 2011 were retrospectively evaluated as follows: length of sternum, external thickness/internal thickness (ET/IT) of the chest and the intrathoracic structures in the level of lower half (LH) of the sternum. In addition, Haller index (HI) and the degree of leftward displacement of the heart were measured. Finally, variables were also measured in an age/sex-matched control group (n=22) with no evidence of any chest wall deformity., Results: The sternal length was not different and LH of the sternum was adequate to compress left ventricle (LV) in both groups. Patients had a significant higher HI and showed a greater leftward displacement of LV centre with a mean difference of 11 mm. PE patients showed a lesser ET/IT with a mean difference of approximately 20 mm than controls (mean ET/IT=174±18/70±10 mm vs 199±23/93±15 mm, p<0.001)., Conclusions: The LH of the sternum is an appropriate chest compression landmark in PE patients to compress LV, although the centre of LV shows slightly leftward displacement. Since PE patients have sunken chest, a 3-4 cm may be the proper compression depth in the patients when considering the current compression guideline in normal subjects is 5-6 cm., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)
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- 2015
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41. Fecopneumothoax: a rare case of delayed colon diaphragmatic herniation following esophagectomy.
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Kim KW, Lee JI, Kim JS, Park KY, Park CH, and Jeon YB
- Abstract
Diaphragmatic hernia after esophagectomy and, particularly, eventual fecopneumothorax is a rare complication. Furthermore, a delayed manifestation 10 years after esophagectomy is an extremely rare situation. Herein, we report a surgical case of fecopneumothorax resulting from the perforation of intrathoracically herniated transverse colon 10 years after McKeown esophagectomy.
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- 2015
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42. CTLA4 overexpressing adipose tissue-derived mesenchymal stem cell therapy in a dog with steroid-refractory pemphigus foliaceus.
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Han SM, Kim HT, Kim KW, Jeon KO, Seo KW, Choi EW, and Youn HY
- Subjects
- Animals, Dog Diseases pathology, Dogs, Immunosuppressive Agents therapeutic use, Male, Pemphigus pathology, Pemphigus therapy, Skin pathology, Adipose Tissue cytology, CTLA-4 Antigen immunology, Dog Diseases therapy, Mesenchymal Stem Cell Transplantation veterinary, Pemphigus veterinary
- Abstract
Background: Canine pemphigus foliaceus is an autoimmune antibody-mediated skin disease characterized by acantholysis. The objective of this case report is to present the successful management of steroid refractory pemphigus foliaceus with cytotoxic T-lymphocyte antigen 4 (CTLA4)-overexpressing adipose tissue mesenchymal stem cells (ATMSCs)., Case Presentation: A 10-year-old, 12.3-kg, castrated male Shih Tzu presented with severe pruritus and anorexia. The diagnosis of pemphigus foliaceus was made based on its history, physical examination, and histopathology results of a skin biopsy. Treatment with prednisolone and combination therapy of other immunosuppressive drugs had failed; therefore, immunosuppressive gene, CTLA4 overexpressing ATMSCs (CTLA4-ATMSCs) and/or naive ATMSCs administration was performed with the consent of the owner. ATMSCs were administered 21 times over a period of 20 months with intervals of 2 to 8 week. Prednisolone was gradually tapered concurrently and no relapse of the clinical signs was observed. After the termination of CTLA4-ATMSCs and/or naive ATMSCs treatment, the skin lesions had improved and could be managed with a low dose of prednisolone for 12 months., Conclusion: CTLA4-ATMSCs or naive ATMSCs transplantation may be beneficial as adjunctive therapy to initiate and maintain the remission of skin lesions caused by pemphigus foliaceus in veterinary medicine.
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- 2015
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43. On-chip magnetometer for characterization of superparamagnetic nanoparticles.
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Kim KW, Reddy V, Torati SR, Hu XH, Sandhu A, and Kim CG
- Subjects
- Particle Size, Lab-On-A-Chip Devices, Magnetite Nanoparticles chemistry, Magnetometry instrumentation
- Abstract
An on-chip magnetometer was fabricated by integrating a planar Hall magnetoresistive (PHR) sensor with microfluidic channels. The measured in-plane field sensitivities of an integrated PHR sensor with NiFe/Cu/IrMn trilayer structure were extremely high at 8.5 μV Oe(-1). The PHR signals were monitored during the oscillation of 35 pL droplets of magnetic nanoparticles, and reversed profiles for the positive and negative z-fields were measured, where magnitudes increased with the applied z-field strength. The measured PHR signals for 35 pL droplets of magnetic nanoparticles versus applied z-fields showed excellent agreement with magnetization curves measured by a vibrating sample magnetometer (VSM) of 3 μL volume, where a PHR voltage of 1 μV change is equivalent to 0.309 emu cc(-1) of the volume magnetization with a magnetic moment resolution of ~10(-10) emu.
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- 2015
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44. Detection of blebs and bullae in patients with primary spontaneous pneumothorax by multi-detector CT reconstruction using different slice thicknesses.
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Lee KH, Kim KW, Kim EY, Lee JI, Kim YS, Hyun SY, Kim HS, and Kim JH
- Subjects
- Adolescent, Adult, Blister complications, Child, Female, Humans, Male, Models, Biological, Observer Variation, Pneumothorax etiology, Radiographic Image Enhancement methods, Reproducibility of Results, Sensitivity and Specificity, Young Adult, Blister diagnostic imaging, Multidetector Computed Tomography methods, Pneumothorax diagnostic imaging, Radiographic Image Interpretation, Computer-Assisted methods
- Abstract
Introduction: The aim of this study was to compare the diagnostic performances of multi-detector computed tomography (MDCT) reconstruction at two different slice thicknesses (1 mm, 'high resolution' vs. 5 mm, 'routine') with respect to the detection of blebs and bullae (BBs) in patients with primary spontaneous pneumothorax (PSP)., Methods: Thirty-one patients underwent wedge resection of BBs (29 unilateral and 2 bilateral) for PSP from January 2010 to January 2013. Two observers assessed the presence and locations of BBs independently using high-resolution CT (HRCT) and routine CT reconstruction, and compared the sensitivities of each reconstruction method for BB detection using operative findings as a standard reference. In addition, the number of BBs in each CT image set was recorded and inter-observer agreements were evaluated., Results: Sensitivity for the detection of BBs was significantly better for HRCT than routine CT (97.0% vs. 63.6% for observer 1 and 94.0% vs. 57.6% for observer 2, respectively, both P-values < 0.001). On a per-bleb and a per-bulla basis, inter-observer agreements regarding BBs by HRCT were good and very good (k = 0.66 and 0.94, respectively) and superior to those determined by routine CT (k = 0.59 and 0.60, respectively)., Conclusion: Different slice thickness reconstructions influence the diagnostic efficacy of MDCT for the detection of BBs in patients with PSP. High-resolution thin slice CT reconstruction was found to have a significantly greater sensitivity than routine thicker slice thickness reconstruction for the detection of BBs., (© 2014 The Royal Australian and New Zealand College of Radiologists.)
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- 2014
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45. The clinical practice patterns of fetal ultrasonography in the first-trimester: A questionnaire survey of members of the Korean Society of Ultrasound in Obstetrics and Gynecology.
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Kim KW, Kwak DW, Ko HS, Park HS, Seol HJ, Hong JS, Yang SW, Hwang HS, Oh SY, Kim MY, and Kim SJ
- Abstract
Objective: This study aimed to survey the current clinical practice of first-trimester ultrasonography among members of the Korean Society of Ultrasound in Obstetrics and Gynecology (KSUOG) and to provide basic data for making practical recommendations about first-trimester ultrasonography scan in Korea., Methods: This survey was conducted using a self-administered anonymous questionnaire. The first-trimester in this survey was divided into two parts: early and late first-trimester. The survey was focused on safety issue, nuchal translucency (NT) cutoff, the anatomic structures they check, and the need for practical recommendations or educational courses during the first-trimester., Results: During the study period, 194 KSUOG members participated into this survey. The survey on early first-trimester scan reveal that 173 (89.2%) of respondents had used pulsed-wave Doppler or color Doppler imaging to monitor fetal heart beat. For the late first-trimester scan, 145 (74.7%) of respondents was found to check for fetal anatomical assessments during their NT screening performance; however, the clinical practice patterns were considerably varied among participants. More than half of the respondents used the criterion of NT ≥3.0 mm to define increased NT. Approximately 80% of respondents stated that the screening ultrasonography of fetal structures in the first-trimester was necessary. Furthermore, 187 (96.4%) of respondents were in favor of a recommendation for first-trimester ultrasonography in Korea., Conclusion: This is the first survey of the current clinical practice of first-trimester ultrasonography in Korea. Our survey findings highlight the need for the practical recommendation or educational course for first-trimester ultrasonography.
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- 2014
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46. Edema of pancreas and gallbladder misread as inflammation in cardiac tamponade.
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Cho HJ, Park CH, Kim JS, Kim KW, Son KH, Choi CH, Lee JI, Jeon YB, and Park KY
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- Cardiac Tamponade complications, Cholecystitis diagnostic imaging, Diagnostic Errors, Edema etiology, Gallbladder Diseases etiology, Humans, Male, Middle Aged, Pancreatic Diseases etiology, Pancreatitis diagnostic imaging, Tomography, X-Ray Computed, Edema diagnostic imaging, Gallbladder Diseases diagnostic imaging, Pancreatic Diseases diagnostic imaging
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- 2014
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47. Third-generation cephalosporin resistance of community-onset Escherichia coli and Klebsiella pneumoniae bacteremia in a secondary hospital.
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Lee S, Han SW, Kim KW, Song DY, and Kwon KT
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- Aged, Aged, 80 and over, Bacteremia epidemiology, Community-Acquired Infections microbiology, Emergency Service, Hospital statistics & numerical data, Female, Humans, Male, Middle Aged, Republic of Korea epidemiology, Retrospective Studies, Secondary Care Centers statistics & numerical data, Bacteremia microbiology, Cephalosporin Resistance, Escherichia coli physiology, Klebsiella pneumoniae physiology
- Abstract
Background/aims: To enable appropriate antimicrobial treatment for community-onset infections in emergency departments (EDs), data are needed on the resistance profiles of Escherichia coli and Klebsiella pneumoniae, which are the main pathogens of community-onset bacteremia., Methods: Records were reviewed of 734 patients with E. coli and K. pneumoniae bacteremia who visited the Daegu Fatima Hospital ED, Daegu, Korea between 2003 and 2009. We investigated the demographic data, clinical findings, and antimicrobial susceptibility patterns of the organisms., Results: Of 1,208 cases of community-onset bacteremia, 62.8% were caused by E. coli or K. pneumoniae in an ED of a secondary care hospital. Five hundred and forty-eight cases of E. coli (75%) and 183 cases of K. pneumoniae (25%) were analyzed. Urinary tract infection (43.1%) was most common, followed by intra-abdominal infection (39%) and pneumonia (7.2%). Trimethoprim/sulfamethoxazole, fluoroquinolone, third-generation cephalosporin (3GC) and amikacin resistance rates among E. coli and K. pneumoniae were 22.8%, 19.6%, 6.2%, and 1.3%, respectively. In 2009, the rate of 3GC resistance (10.6%) was significantly higher, compared to the annual averages of 2003 to 2008 (6.1%; p = 0.03). Previous exposure to antibiotics was an independent risk factor for 3GC resistance in multivariate logistic regression analysis., Conclusions: The rate of 3GC resistance increased in community-onset infections, and previous exposure to antibiotics was an independent risk factor. Despite the increased 3GC resistance in community-onset infections, an amikacin combination therapy could provide an option for treatment of bacteremic patients with previous antibiotic exposure in an ED.
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- 2014
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48. Parameter optimization for applying the prepulse gap paradigm to humans.
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Suh MW, Kim KW, Park IY, and Oh SH
- Abstract
Background and Objectives: Turner and colleagues introduced a new method that can detect tinnitus in animals. The stimulus is composed of a small background noise that is identical to the pitch of the tinnitus and a large pulse noise that can evoke a startle response. In normal rats, the gap decreases the startle reflex. However, in tinnitus rats, the gap does not decrease the startle reflex. The goal of this study was to optimize the stimulation paradigm so that the prepulse inhibition of N1-P2 amplitude would be maximized in the normal human subjects., Subjects and Methods: Seven normal control subjects without tinnitus were recruited. The stimulus was composed of two different sounds: the softer background noise and the louder pulse noise. A 50 msec silent gap was inserted before the pulse noise as the gap condition (G condition) but not in the no-gap condition (N condition). The averaged amplitude of the N1-P2 cortical response was recorded for the G and N conditions., Results: The G/N ratio was the smallest when the gap was 20 msec prior to the pulse noise. The G/N ratio was 84.8±16.8% with the Hanning window and 78.5±5.9% without the window. The G/N ratio was 91.1±24.9%, 78.0±5.4%, and 79.0±18.1% when the intensity of the background noise was 10, 20, and 32 dB SL, respectively. When the intensity of the background noise was 20 and 32 dB SL, the N1-P2 amplitude of the G condition was significantly smaller than that of the N condition., Conclusions: The optimal stimulus should be composed of the 1 kHz pulse noise without Hanning window. The intensity of the background noise should be 20 dB HL and the location of the gap should be 20 msec prior to the pulse noise. It seems that with these optimized parameters we could expect a 78.0% inhibition of N1-P2 amplitude in normal subjects without tinnitus.
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- 2013
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49. Capacity of rectified vestibular evoked myogenic potential in correcting asymmetric muscle contraction power.
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Kim KW, Jung JY, Lee JH, and Suh MW
- Abstract
Objectives: Rectified vestibular evoked myogenic potential (rVEMP) is new method that simultaneously measures the muscle contraction power during VEMP recordings. Although there are a few studies that have evaluated the effect of the rVEMP, there is no study that has evaluated the capacity of rVEMP during asymmetrical muscle contraction., Methods: Thirty VEMP measurements were performed among 20 normal subjects (mean age, 28.2±2.1 years; male, 16). VEMP was measured in the supine position. The head was turned to the right side by 0°, 15°, 30°, and 45° and the VEMPs were recorded in each position. The interaural amplitude difference (IAD) ratio was calculated by the conventional non-rectified VEMP (nVEMP) and rVEMP., Results: The nVEMP IAD increased significantly according to increasing neck rotation. The IAD in rVEMP was almost similar from 0° to 30°. However, the IAD was significantly larger than the other positions when the neck was rotated 45°. When IAD during 0° was set as a standard, the IAD of the rVEMP was significantly smaller that the nVEMP only during the 30°rotaion., Conclusion: Rectified VEMP is capable of correcting asymmetrical muscle contraction power. In contrast, it cannot correct the asymmetry if muscle contraction power asymmetry is 44.8% or larger. Also, it is not necessary if muscle contraction power asymmetry is 22.5% or smaller.
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- 2013
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50. Gastrointestinal cancers in a peutz-jeghers syndrome family: a case report.
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Song SH, Kim KW, Kim WH, Kwon CI, Ko KH, Hahm KB, Park PW, and Hong SP
- Abstract
A 17-year-old man was diagnosed as Peutz-Jeghers syndrome (PJS) because of pigmented lip and multiple gastrointestinal polyps. He had anemia and underwent polypectomy on the duodenum and colon. His maternal family members were patients with PJS. His mother used to be screened with endoscopy to remove large polyps. One and half years later, he underwent jejunal segmental resection due to intussusceptions. He underwent endoscopic polypectomy every 2 to 3 years. When he was 23 years old, high-grade dysplasia was found in colonic polyp and his mother underwent partial pancreatectomy due to intraductal papillary mucinous carcinoma. When he was 27 years old, diffuse gastric polyps on the greater curvature of corpus expanded and grew. Therefore, wide endoscopic polypectomy was done. Histological examination revealed focal intramucosal carcinoma and low-grade dysplasia in hamartomatous polyps. We report cases of cancers occurred in first-degree relatives with PJS.
- Published
- 2013
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