55 results on '"Kwak HY"'
Search Results
2. Atypical vitelliform macular dystrophy misdiagnosed as chronic central serous chorioretinopathy: case reports
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Lee Young, Kim Eung-Suk, Kim Moosang, Kim Young-Gyun, Kwak Hyung-Woo, and Yu Seung-Young
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Ophthalmology ,RE1-994 - Abstract
Abstract Background To report two cases of atypical vitelliform macular dystrophy misdiagnosed as chronic central serous chorioretinopathy. Case presentation Two patients with incidentally discovered abnormalities of the retina without specific symptoms were referred to our hospital for consultation. Bilateral macula atrophic lesions were observed and optical coherence tomography revealed serous retinal detachment in the macula. Fluorescein angiography showed multiple leakages around the central hypofluorescent area and indocyanine green angiography showed partially dilated choroidal vessels. Fundus autofluorescence (FAF) showed a decreasing pattern of autofluorescence in the subretinal fluid area, and increasing autofluorescence at the border of the serous retinal detachment. Both patients were diagnosed with chronic central serous chorioretinopathy. Photodynamic therapy and intravitreal bevacizumab injection were administered for engorged choroidal vessels during follow-up, but neither patient showed improvement in symptoms or ophthalmologic findings. Based on re-evaluation by fundus photography, optical coherence tomography, fluorescein angiography, and comparison of the results of FAF with the first visit, vitelliform macular dystrophy was suspected and a definite diagnosis was made by electrooculography and genetic testing. Conclusion In patients with continuous serous retinal detachment without response to photodynamic therapy or intravitreal bevacizumab injection, careful fundus exam and FAF can be used to diagnose atypical vitelliform macular dystrophy.
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- 2012
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3. Design of DNA Storage Coding Scheme With LDPC Codes and Interleaving.
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Kim JW, Jeong J, Kwak HY, and No JS
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- Computers, Molecular, Sequence Analysis, DNA methods, Algorithms, Genetic Code genetics, DNA genetics, DNA chemistry
- Abstract
In this paper, we propose a new coding scheme for DNA storage using low-density parity-check (LDPC) codes and interleaving techniques. While conventional coding schemes generally employ error correcting codes in both inter and intra-oligo directions, we show that inter-oligo LDPC codes, optimized by differential evolution, are sufficient in ensuring the reliability of DNA storage due to the powerful soft decoding of LDPC codes. In addition, we apply interleaving techniques for handling non-uniform error characteristics of DNA storage to enhance the decoding performance. Consequently, the proposed coding scheme reduces the required number of oligo reads for perfect recovery by 26.25% ~ 38.5% compared to existing state-of-the-art coding schemes. Moreover, we develop an analytical DNA channel model in terms of non-uniform binary symmetric channels. This mathematical model allows us to demonstrate the superiority of the proposed coding scheme while isolating the experimental variation, as well as confirm the independent effects of LDPC codes and interleaving techniques.
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- 2024
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4. Energy, Exergetic, and Thermoeconomic Analyses of Hydrogen-Fueled 1-kW Proton-Exchange Membrane Fuel Cell.
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Yoo Y, Lee SY, Seo SH, Oh SD, and Kwak HY
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Exergy analysis evaluates the efficiency of system components by quantifying the rate of entropy generation. In general, the exergy destruction rate or irreversibility rate was directly obtained through the exergy balance equation. However, this method cannot determine the origin of the component's entropy generation rate, which is a very important factor in system design and improvement. In this study, a thorough energy, exergy, and thermoeconomic analysis of a proton-exchange membrane fuel cell (PEMFC) was performed, providing the heat transfer rate, entropy generation rate, and cost loss rate of each component. The irreversibility rate of each component was obtained by the Gouy-Stodola theorem. Detailed and extensive exergy and thermoeconomic analyses of the PEMFC system determined that water cooling units experience the greatest heat transfer among the components in the studied PEMFC system, resulting in the greatest irreversibility and, thus, the greatest monetary flow loss.
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- 2024
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5. Clinical pathways for Korean medicine: An implementation approach to impact on the clinical process and association with attitudes.
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Hyun E, Kim H, Kwak HY, and Kim D
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Background: South Korea's Ministry of Health and Welfare has developed clinical pathways for Korean Medicine (KM-CPs). As part of this initiative, a panel comprising Korean Medicine doctors (KMD) was assembled. This implementation study aimed to preliminarily explore how KM-CP implementation affects the appropriateness and efficiency of the clinical process and its relation to attitude., Methods: Through random sampling, 311 KMDs were recruited as panelists to participate in two surveys. The surveys included information regarding the KM clinical environment and KM-CP implementation. A panel management program and educational materials were provided to KMDs between the two survey periods. Only 262 KMDs who responded to both surveys were included in the analysis. Three analyses were conducted: 1) descriptive analysis of the study variables, 2) panel analysis using the ordered logit regression model to elucidate the impact of KM-CP on the appropriateness and efficiency of the clinical process, and 3) ordered logit regression analysis of the association between KM-CP implementation and attitude., Results: More than two-thirds of the KMDs attempted to adopt KM-CP, with mostly positive perception expressed by these doctors. However, expectations and concerns coexist with the standardization of KM-CP. Cases in which KM-CPs were partially and mostly implemented respectively had negative and positive effects on the appropriateness and efficiency of the clinical process compared to those in which KM-CPs were not implemented . Compared to neutral attitude , positive and very positive attitudes tended to be associated with increased implementation of KM-CP. However, statistical significances were not observed., Conclusions: The impact of KM-CP on the clinical process and its association with attitude were found to be statistically unclear or inconsistent. Considering the study limitations and implications, we suggest a policy and academic strategies aimed at fostering improvement to enhance its utility., Competing Interests: 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., (© 2024 The Authors.)
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- 2024
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6. Iterative Soft Decoding Algorithm for DNA Storage Using Quality Score and Redecoding.
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Jeong J, Park H, Kwak HY, No JS, Jeon H, Lee JW, and Kim JW
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- Sequence Analysis, DNA methods, Information Storage and Retrieval, DNA genetics, DNA chemistry, High-Throughput Nucleotide Sequencing methods, Algorithms
- Abstract
Ever since deoxyribonucleic acid (DNA) was considered as a next-generation data-storage medium, lots of research efforts have been made to correct errors occurred during the synthesis, storage, and sequencing processes using error correcting codes (ECCs). Previous works on recovering the data from the sequenced DNA pool with errors have utilized hard decoding algorithms based on a majority decision rule. To improve the correction capability of ECCs and robustness of the DNA storage system, we propose a new iterative soft decoding algorithm, where soft information is obtained from FASTQ files and channel statistics. In particular, we propose a new formula for log-likelihood ratio (LLR) calculation using quality scores (Q-scores) and a redecoding method which may be suitable for the error correction and detection in the DNA sequencing area. Based on the widely adopted encoding scheme of the fountain code structure proposed by Erlich et al., we use three different sets of sequenced data to show consistency for the performance evaluation. The proposed soft decoding algorithm gives 2.3% ∼ 7.0% improvement of the reading number reduction compared to the state-of-the-art decoding method and it is shown that it can deal with erroneous sequenced oligo reads with insertion and deletion errors.
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- 2024
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7. Nucleation Process in Explosive Boiling Phenomena of Water on Micro-Platinum Wire.
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Yoo Y and Kwak HY
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The maximum temperature limit at which liquid boils explosively is referred to as the superheat limit of liquid. Through various experimental studies on the superheating limit of liquids, rapid evaporation of liquids has been observed at the superheating limit. This study explored the water nucleation process at the superheat limit achieved in micro-platinum wires using a molecular interaction model. According to the molecular interaction model, the nucleation rate and time delay at 576.2 K are approximately 2.1 × 10
11 /(μm3 μs) and 5.7 ns, respectively. With an evaporation rate (116.0 m/s) much faster than that of hydrocarbons (14.0 m/s), these readings show that explosive boiling or rapid phase transition from liquid to vapor can occur at the superheat limit of water. Subsequent bubble growth after bubble nucleation was also considered.- Published
- 2023
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8. Acupuncture Therapy for Military Veterans Suffering from Posttraumatic Stress Disorder and Related Symptoms: A Scoping Review of Clinical Studies.
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Kwak HY, Leem J, Seung HB, Kwon CY, Jeong HS, and Kim SH
- Abstract
Military personnel in combat face a high risk of developing posttraumatic stress disorder (PTSD). In this study, a protocol-based scoping review was conducted to identify the current status of research on the efficacy of acupuncture for treating combat-related PTSD in military personnel. A literature search was conducted across 14 databases in November 2022, and data from the included studies were collected and descriptively analyzed. A total of eight studies were included. Participants were assessed for core PTSD symptoms using the PTSD Checklist for Diagnostic and Statistical Manual of Mental Disorders-5 and the Clinician-Administered PTSD Scale, as well as related symptoms, such as sleep issues. Although the efficacy of acupuncture has been substantiated in numerous studies, certain metrics did not exhibit improvement. Auricular acupuncture was the most commonly used treatment (50%) followed by manual acupuncture (25%) and a combination of both (25%). Shenmen and Kidney points were frequently targeted at auricular acupoints. The treatment period varied between 5 days and 2 months. While adverse events were reported in two of the fifty-five patients in the intervention group and in four of the sixty-four patients in the control group in the randomized controlled trial studies, no fatal adverse events were reported.
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- 2023
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9. Acupuncture for military veterans with posttraumatic stress disorder and related symptoms after combat exposure: Protocol for a scoping review of clinical studies.
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Seung HB, Leem J, Kwak HY, Kwon CY, and Kim SH
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- Humans, Review Literature as Topic, Acupuncture Therapy methods, Military Personnel, Stress Disorders, Post-Traumatic therapy, Veterans
- Abstract
Posttraumatic stress disorder is caused by traumatic events such as death, serious injury, and sexual violence. Military personnel and veterans are at high risk for posttraumatic stress disorder. Conventional posttraumatic stress disorder treatments have certain limitations. Complementary and integrative medicine treatments, especially acupuncture, are potential novel first-line treatments that may overcome these limitations. We aim to investigate the current status of the available clinical evidence related to acupuncture treatment for posttraumatic stress disorder in war veterans. We will follow the scoping review process as previously described. The study question is as follows: "Which types of clinical research designs, study types, study durations, adverse events, and clinical outcomes have been reported regarding acupuncture therapy for posttraumatic stress disorder in military veterans?" We will perform a comprehensive search of Medline, Excerpta Medica dataBASE, Cochrane Central Register of Controlled Trials, Web of Science, Scopus databases, Allied and Complementary Medicine Database, Cumulative Index to Nursing and Allied Health Literature, and PsycArticles databases, as well as Chinese, Korean, and Japanese databases, from inception to June 2022. Data from the included studies will be collected and descriptively analyzed in relation to our research question. The extracted data will be collated, synthesized, and summarized according to the analytical framework of a scoping review. The protocol of this study adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews to ensure the clarity and completeness of our reporting in all phases of this scoping review (Protocol registration: https://osf.io/t723f/). The findings of this scoping review will provide fundamental data that will help researchers identify appropriate research questions and design further studies on the use of acupuncture for PTSD management in military veterans. These results will be helpful for developing disaster site-specific research protocols for future clinical trials on this topic., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Seung et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2023
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10. Immunogenicity and Protection against Foot-and-Mouth Disease Virus in Swine Intradermally Vaccinated with a Bivalent Vaccine of Foot-and-Mouth Disease Virus Type O and A.
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Kim DW, Cho G, Kim H, Lee G, Lim TG, Kwak HY, Park JH, and Park SH
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Following the worst outbreak of foot-and-mouth disease (FMD), a highly contagious disease in cloven-hoofed animals caused by the FMD virus, from November 2010-April 2011, the Korean government enforced a mandatory vaccination policy. A bivalent (FMD type O and A; O + A) vaccine has been recently implemented. Although the FMD outbreak was suppressed by vaccination, the intramuscular (IM) injection presents side effects. Therefore, improving FMD vaccine quality is necessary. Here, we investigated the side effects and immune efficacy of the O + A bivalent vaccine using two different routes of administration: intradermal (ID) and IM. To compare the immune efficacy of the two inoculation routes, virus neutralization titers and structural protein (antigen) levels were measured. The protective efficacy of ID vaccines was confirmed using two viruses (FMDV O/AS/SKR/2019 and A/GP/SKR/2018) isolated in the Republic of Korea. Serological analysis revealed that both animals administered by ID and IM injections exhibited equal immune efficacy. A virus challenge test in the target animal (swine) revealed no (or extremely low) clinical symptoms. Swine in the ID injected group exhibited no side effects. In conclusion, we suggest that the ID route of vaccination is an effective alternative to the existing IM route, which is associated with more frequent side effects.
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- 2023
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11. Longevity of coal waste for controlling cadmium-contaminated groundwater considering groundwater velocity.
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Kim JH, Kwak HY, Kwak E, Kim BJ, and Lee S
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- Cadmium, Coal, Environmental Pollution, Metals, Heavy, Groundwater, Water Pollutants, Chemical analysis
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Coal waste composed of naturally occurring minerals is applicable as a reactive medium to permeable reactive barriers due to its reactivity to heavy metals. In this study, we evaluated the longevity of coal waste as PRB media to control heavy metal-contaminated groundwater considering variable groundwater velocity. Breakthrough experiments were conducted using coal waste-filled column by injecting artificial groundwater, 10 mg/L of cadmium solution. The artificial groundwater was fed to the column at different flow rates to mimic a wide range of porewater velocities in the saturated zone. The reaction between cadmium breakthrough curves was analyzed using a two-site nonequilibrium sorption model. The cadmium breakthrough curves showed a significant retardation, which increased with decreasing porewater velocity. The greater the retardation, the longer the longevity of coal waste could be expected. The greater retardation under a slower velocity environment was due to the higher fraction of equilibrium reaction. The nonequilibrium reaction parameters could be functionalized with respect to the porewater velocity. The simulation of contaminant transport using the reaction parameters could be used as a method to evaluate the longevity of the pollution-blocking material in an underground environment., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2023
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12. Comparison of Diagnostic Performance in Mammography Assessment: Radiologist with Reference to Clinical Information Versus Standalone Artificial Intelligence Detection.
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Choi WJ, An JK, Woo JJ, and Kwak HY
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We compared diagnostic performances between radiologists with reference to clinical information and standalone artificial intelligence (AI) detection of breast cancer on digital mammography. This study included 392 women (average age: 57.3 ± 12.1 years, range: 30−94 years) diagnosed with malignancy between January 2010 and June 2021 who underwent digital mammography prior to biopsy. Two radiologists assessed mammographic findings based on clinical symptoms and prior mammography. All mammographies were analyzed via AI. Breast cancer detection performance was compared between radiologists and AI based on how the lesion location was concordant between each analysis method (radiologists or AI) and pathological results. Kappa coefficient was used to measure the concordance between radiologists or AI analysis and pathology results. Binominal logistic regression analysis was performed to identify factors influencing the concordance between radiologists’ analysis and pathology results. Overall, the concordance was higher in radiologists’ diagnosis than on AI analysis (kappa coefficient: 0.819 vs. 0.698). Impact of prior mammography (odds ratio (OR): 8.55, p < 0.001), clinical symptom (OR: 5.49, p < 0.001), and fatty breast density (OR: 5.18, p = 0.008) were important factors contributing to the concordance of lesion location between radiologists’ diagnosis and pathology results.
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- 2022
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13. Meditation-based intervention for obsessive-compulsive disorder: A PRISMA-compliant systematic review and meta-analysis.
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Lee SM, Suh HW, Kwak HY, Kim JW, and Chung SY
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- China, Combined Modality Therapy, Humans, Medicine, East Asian Traditional methods, Meditation, Obsessive-Compulsive Disorder therapy
- Abstract
Background: The purpose of this study was to investigate the effects of the meditation-based intervention on obsessive-compulsive disorder (OCD)., Methods: The following databases were searched up to April 2021: the Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, Medline (via PubMed), PsycARTICLES, 4 Korean databases (Korean Medical Database [KMbase], Koreanstudies Information Service System [KISS], National Digital Science Library [NDSL], and Oriental Medicine Advanced Searching Integrated System [OASIS]), and China National Knowledge Infrastructure (CNKI). The search terms related to meditation-based intervention and OCD were used. This systematic review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The selected articles were evaluated using the Cochrane risk of bias tool. The Review Manager (RevMan) 5.4 was used to perform the meta-analysis., Results: In all, 16 randomized controlled trials were selected. The meta-analysis showed that the group receiving the treatment combining medication and meditation-based intervention for OCD showed a more significant post-treatment improvement in Yale-Brown obsessive compulsive scale than the group receiving medication only. Compared with other non-medication interventions that are known to be effective in treating OCD, the Yale-Brown obsessive compulsive scale showed a significant improvement immediately after the meditation-based intervention. However, no significant difference was found in the follow-up monitoring data across all examined cases., Conclusion: This study was conducted to verify the effects of meditation-based intervention on OCD. The results suggested that combined treatment with medication and meditation-based intervention was more effective in treating OCD than medication alone; the positive effects of meditation-based intervention may be greater than the effects of other non-medication interventions. However, the lack of significant difference in the follow-up indicates that long-term effect of meditation-based interventions is unclear., Trial Registration Number: PROSPERO CRD42021244408., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 the Author(s). Published by Wolters Kluwer Health, Inc.)
- Published
- 2022
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14. Efficacy and safety of Gyejibokryeong-hwan (GBH) in major depressive disorder: study protocol for multicentre randomised controlled trial.
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Choi Y, Jung IC, Kim JY, Cho SH, Kim Y, Chung SY, Kwak HY, Lee DS, Lee W, Nam IJ, Yang C, and Lee MY
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- Humans, Multicenter Studies as Topic, Randomized Controlled Trials as Topic, Antidepressive Agents adverse effects, Depressive Disorder, Major drug therapy, Phytotherapy adverse effects
- Abstract
Background: Gyejibokryeong-hwan (GBH) is an herbal medicine composed of five herbs. It has been widely used to treat gynaecological diseases in traditional East Asian medicine. Recent animal studies suggest antidepressant effects of GBH. In this trial, we explore the efficacy and safety of GBH in patients with major depressive disorder and to identify the optimal dose for the next phase III trial., Methods: This trial will enrol 126 patients diagnosed with major depressive disorder and not treated with antidepressants. Participants will be randomised to receive a high or a low dose of GBH or placebo granules. The study drugs will be administered three times a day, for 8 weeks. The 17-item Hamilton Depression Rating Scale (HDRS) will be used to measure the severity of depressive symptoms at weeks 2, 4, 6, 8, and 12. The primary efficacy endpoint is the change from baseline in HDRS-17 total score post-treatment at week 8. Analysis of covariance will be based on the baseline HDRS-17 total score and site as the covariates. Safety assessment will be based on the frequency of adverse events. The severity and causality of the study drug will be assessed., Discussion: This study is designed to evaluate the efficacy and safety of GBH granules compared with placebo in patients with major depressive disorder., Trial Registration: Clinical Research Information Service KCT0004417 . Registered on November 1, 2019 (prospective registration)., (© 2022. The Author(s).)
- Published
- 2022
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15. Effectiveness and Safety of the Korean Medicine Senior Health Promotion Program Using Herbal Medicine and Acupuncture for Mild Cognitive Impairment: A Retrospective Study of 500 Patients in Seoul, Korea.
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Suh HW, Seol JH, Bae EJ, Kwak HY, Hong S, Park YS, Lim JH, and Chung SY
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Background: The management of mild cognitive impairment (MCI) is becoming increasingly important. The Korean Medicine Senior Health Promotion Program (KSHPP) was developed in 2016, and it has been in use to date. This study aimed to assess the effectiveness of KSHPP using herbal medicine and acupuncture for treating MCI and the safety of herbal medicine using liver and renal function tests., Methods: We retrospectively reviewed the medical records of the participants with MCI. We assessed the Korean version of the Montreal Cognitive Assessment (MoCA-K), the Mini-Mental State Examination-Dementia Screening (MMSE-DS), and the Geriatric Depression Scale Short Form-Korea version (GDSSF-K) scores before and after KSHPP to determine its effectiveness. To evaluate its safety, the liver and renal function tests were conducted before and after herbal treatment., Results: We enrolled 1002 participants, and 500 participants satisfied the inclusion criteria. Of 500 patients, 364 (72.8%) were depressed and 136 (27.2%) were not. The mean MoCA-K score significantly increased by 2.77 for the entire sample and 3.22 for the depressed sample (all P < 0.0001). The mean MMSE-DS score significantly increased by 2.19 for the entire sample and 2.51 for the depressed sample (all P < 0.0001); the mean GDSSF-K score significantly decreased by 1.73 for the entire sample and 2.68 for the depressed sample (all P < 0.0001)., Conclusions: Our findings suggest that Korean medicine interventions can improve cognitive function and depression symptoms in patients with MCI. In addition, the results of the liver and renal function tests were analyzed as surrogate outcomes to assess the safety of herbal medicine. Based on these results, we expect that Korean medicine interventions can promote the cognitive and mental health of seniors. However, as there were several study limitations, particularly study design, practice effect, and short follow-up, these results must be interpreted with caution. We need a further long-term study with a rigorous design to retain confidence in the effectiveness and safety of KSHPP., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2021 Hyo-Weon Suh et al.)
- Published
- 2021
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16. Breast adenoid cystic carcinoma arising in microglandular adenosis: A case report and review of literature.
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An JK, Woo JJ, Kim EK, and Kwak HY
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Background: Breast adenoid cystic carcinoma (AdCC) is a rare invasive carcinoma composed of epithelial and myoepithelial cells. Microglandular adenosis (MGA) is a rare benign proliferative lesion consisting of small, uniform, and round glands formed by a single layer of epithelial cells and basement membrane without a myoepithelial cell layer. MGA may progress to atypical MGA and carcinoma arising in MGA. Among various invasive carcinomas from MGA, AdCC has been rarely reported. Here, we report a case of AdCC arising in MGA., Case Summary: A 59-year-old woman was diagnosed with a newly developed density on a routine mammogram. The density was similar to or slightly lower than that of the breast parenchyma. Sonography showed an irregular mass with a slightly higher echo than that of fat. Magnetic resonance imaging showed an irregular mass with a similar T1 signal intensity and a slightly higher T2 signal intensity compared to muscles or the breast parenchyma. The lesion showed heterogeneous internal enhancement with an initially slow and delayed persistent enhancing pattern. Microscopically, the tumor was composed of invasive AdCC, in situ AdCC, and MGA. AdCC is composed of basaloid and ductal epithelial cells forming cribriform or solid sheets, or haphazardly scattered small cribriform or tubular glands. MGA showed small glands with a single epithelial lining and retained lumen. S-100 staining was strongly positive in MGA area. The patient underwent breast-conserving surgery with sentinel lymph node biopsy., Conclusion: Breast AdCC arising in MGA showed unique imaging findings that was different from usual invasive cancer., Competing Interests: Conflict-of-interest statement: The authors have no potential conflicts of interest to disclose., (©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.)
- Published
- 2021
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17. Laparoscopic Treatment of Colonic Intussusception Caused by Sigmoid Colon Cancer.
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Kwak HY, Kim MS, Park JW, Kim DH, Lee JH, and Chang YS
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Reports on the laparoscopic treatment for colonic intussusception are exceedingly rare. We report a case of colonic intussusception caused by sigmoid colon cancer which was treated with a laparoscopic approach. A 76-year-old man visited an emergency room with the chief complaint of lower abdominal pain. He was diagnosed with colonic intussusception probably due to sigmoid colon cancer on a CT scan. Upon laparoscopic exploration, sigmoid colon intussusception was noted. Manual reduction was impossible because the colonic walls were friable and due to the possibility of a cancerous leading point. Therefore, the bowel was resected with en bloc Hartmann procedure. Pathology of the resected specimen revealed a tumor measuring 4.5 cm in size and comprising moderately differentiated adenocarcinoma (pT3N0M0, pStage II). The patient's postoperative course was uneventful and was discharged on the 8th day after surgery., Competing Interests: CONFLICT OF INTEREST None., (Copyright © 2020 The Journal of Minimally Invasive Surgery. All rights reserved.)
- Published
- 2020
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18. The 8-Year Management of an Older Breast Cancer Patient by Non-surgical Primary Therapies and Minimized Surgery: A Case Report.
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An JK, Woo JJ, and Kwak HY
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A 74-year-old woman presented with a palpable lesion in her right breast. At the time of her visit, she was taking medications for diabetes, hypertension, tremors, tinnitus, and lumbago. She was also caring for her husband, who had dementia. Imaging studies revealed another lesion in addition to the palpable mass. A core biopsy of the palpable mass confirmed invasive ductal carcinoma. Surgery was recommended to remove both masses. However, the patient refused the operation due to her comorbidities and her husband's nursing needs. A modified treatment process, including non-surgical primary therapies, minimized surgery, and close follow-up, for 8 years proved successful. This report focuses on the points to consider in the treatment and management of older patients with breast cancer.
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- 2020
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19. Using Mind-Body Modalities via Telemedicine during the COVID-19 Crisis: Cases in the Republic of Korea.
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Kwon CY, Kwak HY, and Kim JW
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- Anxiety, Betacoronavirus, COVID-19, Humans, Mental Health, Pandemics, Republic of Korea, SARS-CoV-2, Coronavirus Infections psychology, Mind-Body Therapies, Pneumonia, Viral psychology, Telemedicine methods
- Abstract
The coronavirus disease 2019 (COVID-19) pandemic affected the world, and its deleterious effects on human domestic life, society, economics, and especially on human mental health are expected to continue. Mental health experts highlighted health issues this pandemic may cause, such as depression, anxiety, obsessive compulsive disorder, and post-traumatic stress disorder. Mind-body intervention, such as mindfulness meditation, has accumulated sufficient empirical evidence supporting the efficacy in improving human mental health states and the use for this purpose has been increasing. Notably, some of these interventions have already been tried in the form of telemedicine or eHealth. Korea, located adjacent to China, was exposed to COVID-19 from a relatively early stage, and today it is evaluated to have been successful in controlling this disease. "The COVID-19 telemedicine center of Korean medicine" has treated more than 20% of the confirmed COVID-19 patients in Korea with telemedicine since 9 March 2020. The center used telemedicine and mind-body modalities (including mindfulness meditation) to improve the mental health of patients diagnosed with COVID-19. In this paper, the telemedicine manual is introduced to provide insights into the development of mental health interventions for COVID-19 and other large-scale disasters in the upcoming new-normal era.
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- 2020
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20. Effect of the Emotional Freedom Techniques on anger symptoms in Hwabyung patients: A comparison with the progressive muscle relaxation technique in a pilot randomized controlled trial.
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Kwak HY, Choi EJ, Kim JW, Suh HW, and Chung SY
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- Adult, Anxiety therapy, Depression therapy, Emotions, Female, Humans, Male, Middle Aged, Pilot Projects, Republic of Korea, Treatment Outcome, Anger, Autogenic Training methods, Cognitive Behavioral Therapy methods, Psychophysiologic Disorders therapy
- Abstract
Context: Hwabyung is a psychosomatic disease resulting from the suppression of anger over an extended period. The Emotional Freedom Techniques (EFT) are meridian-based psychotherapy known to cure many psychosomatic diseases, and progressive muscle relaxation (PMR) is a therapeutic method that relieves physical and psychological tension by repeated tensing and relaxation of the muscles., Object: In this study, we compared the effects of EFT and PMR in patients with Hwabyung., Design: 40 patients were enrolled and randomized to receive 4 weeks of group sessions with either EFT (n = 20) or PMR (n = 20). Evaluations were conducted pre- and post-treatment and at 4-week and 24-week follow-ups after session end., Main Outcome Measures: The Hwabyung Scale, Visual Analogue Scale of Hwabyung Symptoms (VAS-HS), Beck Depression Inventory (BDI), State-Trait Anxiety Inventory (STAI), and State-Trait Anger Expression Inventory (STAXI) were administered as self-report tools. The analysis excluded 8 patients who never attended treatment and 1 patient meeting the exclusion criteria., Result: EFT (n = 15) and PMR (n = 16) improved Hwabyung symptoms (-13.95% and -11.46%, respectively), state anxiety (-12.57% and -12.64%, respectively), and depression (-32.11% and -18.68%, respectively) (p < 0.05 for all). Trait anger improved in EFT group (-13.4%, p = 0.004). There were no significant differences between the groups (p > 0.05) except for trait anger at post-treatment (p = 0.022 for between group). No adverse events were reported during the study., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)
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- 2020
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21. Role of Waste Cost in Thermoeconomic Analysis.
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Uysal C and Kwak HY
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Power plants or thermal systems wherein products such as electricity and steam are generated affect the natural environment, as well as human society, through the discharging of wastes. The wastes from such plants may include ashes, flue gases, and hot water streams. The waste cost is of primary importance in plant operation and industrial ecology. Therefore, an appropriate approach for including waste cost in a thermoeconomic analysis is essential. In this study, a method to take waste cost into account in thermoeconomics to determine the production cost of products via thermoeconomic analysis is proposed. The calculation of the waste cost flow rates at the dissipative units and their allocation to system components are important to obtain the production cost of a plant.
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- 2020
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22. Three Dimensional Measurement of Ideal Trajectory of Pedicle Screws of Subaxial Cervical Spine Using the Algorithm Could Be Applied for Robotic Screw Insertion.
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Huh J, Hyun JH, Park HG, and Kwak HY
- Abstract
Objective: To define optimal method that calculate the safe direction of cervical pedicle screw placement using computed tomography (CT) image based three dimensional (3D) cortical shell model of human cervical spine., Methods: Cortical shell model of cervical spine from C3 to C6 was made after segmentation of in vivo CT image data of 44 volunteers. Three dimensional Cartesian coordinate of all points constituting surface of whole vertebra, bilateral pedicle and posterior wall were acquired. The ideal trajectory of pedicle screw insertion was defined as viewing direction at which the inner area of pedicle become largest when we see through the biconcave tubular pedicle. The ideal trajectory of 352 pedicles (eight pedicles for each of 44 subjects) were calculated using custom made program and were changed from global coordinate to local coordinate according to the three dimensional position of posterior wall of each vertebral body. The transverse and sagittal angle of trajectory were defined as the angle between ideal trajectory line and perpendicular line of posterior wall in the horizontal and sagittal plane. The averages and standard deviations of all measurements were calculated., Results: The average transverse angles were 50.60º±6.22º at C3, 51.42º ±7.44º at C4, 47.79º ±7.61º at C5, and 41.24º ±7.76º at C6. The transverse angle becomes more steep from C3 to C6. The mean sagittal angles were 9.72º ±6.73º downward at C3, 5.09º±6.39º downward at C4, 0.08º ±6.06º downward at C5, and 1.67º ±6.06º upward at C6. The sagittal angle changes from caudad to cephalad from C3 to C6., Conclusion: The absolute values of transverse and sagittal angle in our study were not same but the trend of changes were similar to previous studies. Because we know 3D address of all points constituting cortical shell of cervical vertebrae. we can easily reconstruct 3D model and manage it freely using computer program. More creative measurement of morphological characteristics could be carried out than direct inspection of raw bone. Furthermore this concept of measurement could be used for the computing program of automated robotic screw insertion.
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- 2019
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23. Neurocircuitry of acupuncture effect on cognitive improvement in patients with mild cognitive impairment using magnetic resonance imaging: a study protocol for a randomized controlled trial.
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Suh HW, Kim J, Kwon O, Cho SH, Kim JW, Kwak HY, Kim Y, Lee KM, Chung SY, and Lee JH
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- Acupuncture Therapy adverse effects, Brain diagnostic imaging, Brain pathology, Brain physiopathology, Cognition, Cognitive Dysfunction diagnostic imaging, Cognitive Dysfunction psychology, Humans, Magnetic Resonance Imaging, Outcome Assessment, Health Care, Research Design, Acupuncture Therapy methods, Cognitive Dysfunction therapy, Randomized Controlled Trials as Topic
- Abstract
Background: Mild cognitive impairment (MCI) is defined as a decline in cognitive state with preservation of activities of daily living. Medications such as donepezil and rivastigmine have been commonly prescribed for MCI, but their use is controversial. Acupuncture has been widely used in Korea and has been shown to improve cognitive function. The aim of this study is to evaluate the efficacy of acupuncture for MCI and investigate the effect of acupuncture on structural and functional brain changes in patients with MCI., Methods: This study is a randomized, assessor-blinded, sham-controlled trial. Fifty participants with MCI will be randomly assigned to the acupuncture group (n = 25) or sham acupuncture group (n = 25). The acupuncture group will receive acupuncture treatment at nine acupuncture points (GV20, EX-HN1, bilateral LI4, and ST36) twice a week for 12 weeks. The sham acupuncture group will receive sham acupuncture treatment at the same points with non-penetrating sham needles. Both groups will be restricted from all other treatments for the improvement of cognitive function. The primary outcome measure is the Digit Span Test (DST). The secondary outcome measures are the Digit Symbol Substitution Test (DSST), Korean version of Montreal Cognitive Assessment (MoCA-K), Seoul Neuropsychological Screening Battery-II (SNSB-II), Beck Depression Inventory-II (BDI-II), State-Trait Anxiety Inventory (STAI), working memory (WM) task performance score, and structural/functional brain changes. Outcomes will be assessed at screening, baseline, 4 and 8 weeks, and after the end of treatment. We will also observe adverse events. In the statistical analysis, a full analysis set and per-protocol analysis will be performed., Discussion: This randomized clinical trial aims to examine the efficacy of acupuncture treatment for MCI. Neuropsychological tests, psychological inventories for measuring depression and anxiety, and magnetic resonance imaging will be performed to investigate the underlying neurological mechanisms and the association between cognition, emotion, and brain networks following acupuncture treatment. The results of the trial will provide evidence supporting the efficacy of acupuncture and also add to the neurobiological understanding of acupuncture treatment for MCI., Trial Registration: Clinical Research Information Service, KCT0002896 . Registered on 25 May 2018.
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- 2019
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24. Entropy Generation Due to the Heat Transfer for Evolving Spherical Objects.
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Kwak HY
- Abstract
Heat transfer accompanying entropy generation for the evolving mini and microbubbles in solution is discussed based on the explicit solutions for the hydrodynamic equations related to the bubble motion. Even though the pressure difference between the gas inside the bubble and liquid outside the bubble is a major driving force for bubble evolution, the heat transfer by conduction at the bubble-liquid interface affects the delicate evolution of the bubble, especially for sonoluminescing the gas bubble in sulfuric acid solution. On the other hand, our explicit solutions for the continuity, Euler equation, and Newtonian gravitational equation reveal that supernovae evolve by the gravitational force radiating heat in space during the expanding or collapsing phase. In this article, how the entropy generation due to heat transfer affects the bubble motion delicately and how heat transfer is generated by gravitational energy and evolving speed for the supernovae will be discussed. The heat transfer experienced by the bubble and supernovae during their evolution produces a positive entropy generation rate.
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- 2018
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25. Adhesive force measurement of steady-state water nano-meniscus: Effective surface tension at nanoscale.
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Kwon S, Kim B, An S, Lee W, Kwak HY, and Jhe W
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When the surface of water is curved at nanoscale as a bubble, droplet and meniscus, its surface tension is expected to be smaller than that of planar interface, which still awaits experimental studies. Here, we report static and dynamic force spectroscopy that measures the capillary force of a single nanoscale water meniscus at constant curvature condition. Based on the Young-Laplace equation, the results are used to obtain the effective surface tension (ST) of the meniscus, which decreases to less than 20% of the bulk value at the radius-of-curvature (ROC) below 25 nm, while indicating the bulk behaviour above ~130 nm ROC. Interestingly, such a possibility provides a qualitative resolution of the unsettled discrepancies between experiments and theories in the thermodynamic activation processes for the mentioned three types of nano-curvatured water. Our results may not only lead to development of microscopic theories of ST as well as further experimental investigations, but also help better understanding of the ST-induced nanoscale dynamics such as cluster growth or protein folding, and the ST-controlled design of nano-biomaterials using the nano-meniscus.
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- 2018
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26. Predictive factors for longer operative times for thyroidectomy.
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Kwak HY, Dionigi G, Liu X, Sun H, Woo SU, Son GS, Lee JB, Bae JW, and Kim HY
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- Adult, Aged, Carcinoma, Papillary mortality, China, Cohort Studies, Confidence Intervals, Databases, Factual, Female, Humans, Male, Middle Aged, Multivariate Analysis, Neoplasm Invasiveness pathology, Neoplasm Staging, Odds Ratio, Postoperative Complications epidemiology, Postoperative Complications physiopathology, Predictive Value of Tests, Prognosis, Retrospective Studies, Thyroid Cancer, Papillary, Thyroid Neoplasms mortality, Thyroidectomy adverse effects, Treatment Outcome, Young Adult, Carcinoma, Papillary diagnosis, Carcinoma, Papillary surgery, Operative Time, Thyroid Neoplasms diagnosis, Thyroid Neoplasms surgery, Thyroidectomy methods
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Background/objective: Conventional open thyroidectomy is considered as a safe surgery nowadays. However, surgeons sometimes encounter unexpected difficulty when performing thyroidectomies. The aim of this paper was to identify the predictors of a difficult thyroidectomy for the management of patients with papillary thyroid carcinoma., Methods: A database of patients who underwent open conventional thyroidectomy with cervical lymph node dissection after diagnosed papillary thyroid carcinoma between July 2008 and June 2013 was examined. In addition, the patients were subgrouped by difficult thyroidectomy (DT) and nondifficult thyroidectomy to determine the predictors of DT according to operation time. Clinicopathologic characteristics, surgical outcomes, and postoperative morbidities were investigated., Results: No between-group differences in clinicopathologic factors and postoperative complications, except for male sex (p < 0.001) and tumor size (p = 0.039), were noted. Male sex [odds ratio (OR) 4.158, 95% confidence interval (CI) 2.020-8.559, p = 0.043] and age < 45 years (OR 2.239, 95% CI 1.304-3.843, p = 0.003) were independent factors associated with DT in a multivariate logistic regression model. Elevated antithyroglobulin antibody (OR 1.004, 95% CI 1.000-1.008, p = 0.030) was a variable which is statistically significant, but not clinically significant., Discussion: Young age and male sex might be regarded as predictors of DT. Expecting DT before surgery might help surgeons, especially beginners, prevent troublesome situations., (Copyright © 2017. Published by Elsevier Taiwan.)
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- 2017
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27. Acute Cervical Spontaneous Spinal Epidural Hematoma Presenting with Minimal Neurological Deficits: A Case Report.
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Huh J, Kwak HY, Chung YN, Park SK, and Choi YS
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Introduction: Spontaneous spinal epidural hematoma (SSEH) is an uncommon but potentially fatal condition. The increased bleeding tendency associated with anticoagulant medications has been proven to increase the risk of SSEH. The symptoms of SSEH usually begin with sudden severe neck or back pain and are followed by neurological deficits. However, some cases present with only axial pain or with radicular pain similar to herniated disc disorders., Case Presentation: A 28-year-old healthy man developed a sudden onset of severe neck and right shoulder pain with mild arm weakness. The MRI revealed an SSEH that was compressing his spinal cord in the right posterolateral epidural space from C2-C6. On the second hospital day, his symptoms suddenly improved, and most of the hematoma had spontaneously resolved., Conclusions: Currently, the incidence of SSEH is expected to increase. Pain physicians must include SSEH in their differential diagnosis for patients with axial pain or radicular symptoms alone, particularly when risk factors are present.
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- 2016
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28. Impact of positional changes in neural monitoring endotracheal tube on amplitude and latency of electromyographic response in monitored thyroid surgery: Results from the Porcine Experiment.
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Kim HY, Tufano RP, Randolph G, Barczyński M, Wu CW, Chiang FY, Liu X, Masuoka H, Miyauchi A, Park SY, Kwak HY, Lee HY, and Dionigi G
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- Animals, Female, Recurrent Laryngeal Nerve Injuries prevention & control, Swine, Electromyography, Intraoperative Neurophysiological Monitoring, Intubation, Intratracheal, Thyroid Gland surgery
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Background: The purpose of this study was to evaluate electromyography (EMG) amplitude and latency changes during tube dislocation in monitored thyroid surgery, which may be observed without recurrent laryngeal nerve injury., Methods: Duroc-Landrace piglets were intubated with the TriVantage EMG tube. We measured EMG changes during both upward and downward tube dislocation (10-20 mm) and rotation (45-90°) with continuous neuromonitoring., Results: The EMG amplitude varied significantly with induced endotracheal tube rotation and depth changes. However, the EMG latency was relatively unaffected by such tube dislocation, just a transient artifactual latency change was observed in the situation of extreme amplitude variation., Conclusion: Amplitude changes without latency changes may be due to changes in tube position alone during surgery, but could still reflect a neurophysiologic event; amplitude changes during neuropraxic injury merit additional investigation. Thus, the combined event (concordant amplitude decrease and latency increase) serves as an appropriate adverse EMG event correlating with impending neural injury. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1004-E1008, 2016., (© 2015 Wiley Periodicals, Inc.)
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- 2016
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29. Predictive factors for difficult robotic thyroidectomy using the bilateral axillo-breast approach.
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Kwak HY, Kim HY, Lee HY, Jung SP, Woo SU, Son GS, Lee JB, and Bae JW
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- Adult, Axilla, Female, Humans, Male, Middle Aged, Neck Dissection, Retrospective Studies, Risk Factors, Robotic Surgical Procedures, Thyroid Neoplasms surgery, Thyroidectomy methods
- Abstract
Background: The purpose of this study was to identify predictors of difficult robotic thyroidectomy using the bilateral axillo-breast approach (BABA) for the management of patients with papillary thyroid carcinoma (PTC)., Methods: We examined a database containing details of patients with PTC who had undergone robotic thyroidectomy with cervical lymph node dissection between July 2008 and June 2013. Patients were subgrouped into difficult thyroidectomy and non-difficult thyroidectomy to identify predictors associated with difficult thyroidectomy corresponding to the time of operation. Clinicopathologic characteristics, surgical outcomes, and postoperative morbidities were investigated., Results: Male sex was the only significantly different clinicopathologic factor between the 2 groups (p = .013). Other factors, such as age (p = .809) and body mass index (BMI; p = .202), were comparable between the 2 groups. The rates of postoperative complications, such as hypoparathyroidism, vocal cord palsy, and seroma, in the difficult thyroidectomy group were not significantly different from those in the non-difficult thyroidectomy group. There was no hematoma or wound infection. Male sex was the only independent factor associated with difficult thyroidectomy (odds ratio [OR] = 5.379; 95% confidence interval [CI] = 1.052-27.502; p = .043), according to the multivariate logistic regression model., Conclusion: Male sex was the only predictive factor for difficult robotic thyroidectomy using BABA. Further evaluations should be performed to ascertain additional factors associated with difficult robotic thyroidectomy. © 2015 Wiley Periodicals, Inc. Head Neck 38: E954-E960, 2016., (© 2015 Wiley Periodicals, Inc.)
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- 2016
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30. Thermal injury of the recurrent laryngeal nerve by THUNDERBEAT during thyroid surgery: findings from continuous intraoperative neuromonitoring in a porcine model.
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Kwak HY, Dionigi G, Kim D, Lee HY, Son GS, Lee JB, Bae JW, and Kim HY
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- Animals, Electromyography, Female, Monitoring, Intraoperative methods, Recurrent Laryngeal Nerve Injuries diagnosis, Swine, Thyroidectomy adverse effects, Hot Temperature adverse effects, Recurrent Laryngeal Nerve Injuries etiology, Thyroidectomy instrumentation
- Abstract
Background: Recurrent laryngeal nerve (RLN) palsy is the most common and serious complication of thyroid surgery. The use of energy-based devices (EBDs) has replaced hand-tying methods in many institutions. However, EBD use proximal to the RLN presents risks related to lateral thermal spread and associated nerve damage. THUNDERBEAT (TB) is one of the most widely used EBDs. This study aimed to test the safety of TB during thyroidectomy., Methods: Four piglets weighing 30-40 kg experienced thyroidectomy while continuous electrophysiologic monitoring (continuous intraoperative neuromonitoring) occurred, using an electromyography endotracheal tube and NIM 3.0 response system. TB was applied at various distances from the RLN, and we assessed the safety of the protocols., Results: Adverse electromyography events did not occur at distances >3 mm from the RLN. Amplitude decreased at 2 mm from the RLN after 8 s. However, immediate loss of signal occurred at 1 mm from the RLN, likely due to immediate shrinkage of surrounding tissue after TB application., Conclusions: TB can be used safely at 3 mm from the RLN but must be used for <8 s at more proximal locations. This is the first report assessing the safety of TB, and findings indicate that TB should be used at least 1 mm from the RLN to avoid injury., (Copyright © 2016 Elsevier Inc. All rights reserved.)
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- 2016
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31. Is adjuvant chemotherapy omissible in women with T1-2 stage, node-positive, luminal A type breast cancer?
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Kwak HY, Chae BJ, Eom YH, Hong YR, Seo JB, Bae JS, Jung SS, and Song BJ
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- Breast Neoplasms metabolism, Breast Neoplasms mortality, Chemotherapy, Adjuvant, Female, Follow-Up Studies, Humans, Immunoenzyme Techniques, Lymphatic Metastasis, Middle Aged, Neoplasm Grading, Neoplasm Invasiveness, Neoplasm Staging, Prognosis, Prospective Studies, Receptor, ErbB-2 metabolism, Receptors, Estrogen metabolism, Receptors, Progesterone metabolism, Survival Rate, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Biomarkers, Tumor metabolism, Breast Neoplasms drug therapy, Breast Neoplasms pathology
- Abstract
Purpose: The aim of this study was to evaluate whether hormonal breast cancer therapy without systemic chemotherapy is feasible in adjuvant settings in luminal A breast cancer., Methods: A database of 879 patients who underwent breast cancer surgery enrolled between January 2003 and December 2011 was reviewed. Patients with luminal A cancers were selected and grouped into those who received adjuvant hormonal therapy with (group C+) or without (group C - ) adjuvant systemic therapy., Results: In a multivariable analysis, axillary lymph node (ALN) metastasis was the only independent factor that revealed significantly different between the two groups in disease-free survival (DFS). The 5-year cumulative DFS was 82.3 versus 76.2% (P = 0.700) and overall survival (OS) was 83.9 versus 100% (P = 0.483) for C+ versus C - breast cancer, respectively., Conclusion: In our study, adjuvant chemotherapy in luminal A, T1-2N+ cancer showed no significant difference for DFS. We believe that the role of adjuvant chemotherapy for these women with hormonal therapy might have little benefit.
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- 2015
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32. Does papillary thyroid carcinoma have a better prognosis with or without Hashimoto thyroiditis?
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Kwak HY, Chae BJ, Eom YH, Hong YR, Seo JB, Lee SH, Song BJ, Jung SS, and Bae JS
- Subjects
- Adult, Carcinoma complications, Carcinoma surgery, Carcinoma, Papillary, Female, Hashimoto Disease complications, Humans, Male, Middle Aged, Prognosis, Thyroid Cancer, Papillary, Thyroid Neoplasms complications, Thyroid Neoplasms surgery, Thyroidectomy, Carcinoma genetics, Hashimoto Disease genetics, Proto-Oncogene Proteins B-raf genetics, Thyroid Neoplasms genetics
- Abstract
Background: It has been reported that the BRAF (V600E) mutation is related to a low frequency of background Hashimoto thyroiditis (HT); however, there are not many factors known to be related to the development of HT. The aim of this study was to determine whether patients with both papillary thyroid carcinoma (PTC) and HT show aggressive features, by investigating the clinicopathological features of HT in patients with PTC., Methods: A database of patients with PTC who underwent thyroidectomy between October 2008 and August 2012 was collected and reviewed. All 2464 patients were offered a thyroidectomy, and DNA was extracted from the atypical cells in the surgical specimens for detection of the BRAF (V600E) mutation. Clinical and pathological characteristics were also investigated., Results: Four hundred and fifty-two of 1945 (23.2%) patients were diagnosed with HT, and of these, 119 (72.1%) had a BRAF (V600E) mutation. HT was not significantly associated with the BRAF (V600E) mutation (P < 0.001) and extrathyroidal extensions (P = 0.005) but was associated with a low stage (P = 0.011) and female predominance (P < 0.001). In a subgroup analysis for gender, HT was associated with a low probability of BRAF (V600E) mutations in both genders (P < 0.001 for both females and males). Also, recurrence was significantly associated with HT (OR 0.297, CI 0.099-0.890, P = 0.030), lymph node ratio (OR 2.545, CI 1.092-5.931, P = 0.030), and BRAF (V600E) mutation (OR 2.075, CI 1.021-4.217, P = 0.044). However, there was no relationship with clinicopathological factors or with death., Conclusions: Our results show that HT in patients with PTC is associated with a low probability of BRAF (V600E) mutations. Moreover, HT was correlated with some factors that were associated with less aggressive clinical features and inversely related to recurrence. Therefore, these results may be useful to predict whether PTC concurrent with HT exhibits a better prognosis than PTC alone.
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- 2015
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33. Robotic thyroidectomy using bilateral axillo-breast approach: Comparison of surgical results with open conventional thyroidectomy.
- Author
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Kwak HY, Kim HY, Lee HY, Jung SP, Woo SU, Son GS, Lee JB, and Bae JW
- Subjects
- Adult, Axilla surgery, Breast surgery, Carcinoma, Papillary surgery, Female, Humans, Male, Middle Aged, Neck Dissection, Operative Time, Postoperative Complications, Thyroid Neoplasms surgery, Robotic Surgical Procedures adverse effects, Thyroidectomy methods
- Abstract
Background: The aim of the present study was to compare the surgical outcomes of robotic thyroidectomy using the bilateral axillo-breast approach (BABA) with open conventional thyroidectomy., Methods: Database of patients who underwent thyroidectomy with cervical lymph node dissection after diagnosed as papillary thyroid carcinoma between July 2008 and February 2013 were examined. Clinicopathologic characteristics, surgical outcomes, and postoperative morbidities of robot group and open group were investigated., Results: The dominant tumor size (P=0.974), body mass index (BMI) (P=0.426), and the mean number of metastatic lymph nodes in central compartment neck dissection (P=0.269) were comparable between the two groups. The mean number of retrieved central lymph nodes was higher in the open group than in the robot group (P=0.001). Postoperative complications were comparable: hypoparathyroidism in 2 weeks (P=0.296) and 3 months (P=0.446) after the surgery; vocal cord palsy in 2 weeks (P=0.363) and 3 months (P=0.312); hematoma (P=0.162); and wound infection (P=0.421)., Conclusions: Robotic thyroidectomy using BABA may be a technically feasible and safe procedure comparable to conventional open surgery especially in node-negative patients., (© 2014 Wiley Periodicals, Inc.)
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- 2015
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34. Learning curve for gasless endoscopic thyroidectomy using the trans-axillary approach: CUSUM analysis of a single surgeon's experience.
- Author
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Kwak HY, Kim SH, Chae BJ, Song BJ, Jung SS, and Bae JS
- Subjects
- Adult, Axilla, Endoscopy statistics & numerical data, Female, Humans, Hypocalcemia etiology, Lymph Node Excision, Male, Middle Aged, Thyroid Neoplasms surgery, Thyroidectomy statistics & numerical data, Vocal Cord Paralysis etiology, Endoscopy methods, Learning Curve, Operative Time, Thyroidectomy methods
- Abstract
Background: Endoscopic thyroidectomy and endoscopic parathyroidectomy were first reported in the 1990s. However, there have been few studies reporting on the learning curve of endoscopic thyroidectomy. We used the moving average method and cumulative sum (CUSUM) analysis to assess the learning curve of gasless endoscopic thyroidectomy., Methods: Three hundred consecutive patients with thyroid carcinoma underwent gasless endoscopic thyroidectomy between September 2008 and February 2012. Patients were divided into two groups according to the type of operation they underwent; group L included hemithyroidectomy patients, and group T included total thyroidectomy patients. Endoscopic total thyroidectomy was performed mostly after the time endoscopic lobectomy could be done without difficulty. The results of surgical outcome were analyzed for changes over the case sequence in each group by using the moving average method and CUSUM analysis., Results: The mean operation time of group T (131 ± 41 min) was longer than that of group L (102 ± 33 min; p < 0.05). The moving average method showed that the operation time began to decrease from the 60th case and the 38th case in groups L and T, respectively. However, other factors such as transient hypocalcemia, transient vocal cord palsy and the number of the retrieved lymph nodes had no learning curves based on the moving average method and CUSUM analysis., Conclusions: The learning curve duration of gasless endoscopic thyroidectomy is about 60 cases for unilateral lobectomy. Thereafter, the learning curve of endoscopic total thyroidectomy is 38 cases. Careful dissections must be carried out to avoid surgical complications even after the surgeon mastered endoscopic thyroidectomy., (Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2014
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35. Hydrodynamic approach to multibubble sonoluminescence.
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Mahmood S, Yoo Y, Oh J, and Kwak HY
- Abstract
The velocity profile and radiation pressure field of a bubble cluster containing several thousand micro bubbles were obtained by solving the continuity and momentum equations for the bubbly mixture. In this study, the bubbles in the cluster are assumed to be generated and collapsed synchronously with an applied ultrasound. Numerical calculations describing the behavior of a micro bubble in a cluster included the effect of the radiation pressure field from the synchronizing motion of bubbles in the cluster. The radiation pressure generated from surrounding bubbles affects the bubble's behavior by increasing the effective mass of the bubble so that the bubble expands slowly to a smaller maximum size. The light pulse width and spectral radiance from a bubble in a cluster subjected to ultrasound were calculated by adding a radiation pressure term to the Keller-Miksis equation, and the values were compared to experimental values of the multibubble sonoluminescence condition. There was close agreement between the calculated and observed values., (Copyright © 2014 Elsevier B.V. All rights reserved.)
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- 2014
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36. Approaches to label-free flexible DNA biosensors using low-temperature solution-processed InZnO thin-film transistors.
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Jung J, Kim SJ, Lee KW, Yoon DH, Kim YG, Kwak HY, Dugasani SR, Park SH, and Kim HJ
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- DNA analysis, Elastic Modulus, Equipment Design, Equipment Failure Analysis, Indium chemistry, Reproducibility of Results, Sensitivity and Specificity, Staining and Labeling, Temperature, Zinc Oxide chemistry, Biosensing Techniques instrumentation, Conductometry instrumentation, DNA genetics, Membranes, Artificial, Oligonucleotide Array Sequence Analysis instrumentation, Sequence Analysis, DNA instrumentation, Transistors, Electronic
- Abstract
Low-temperature solution-processed In-Zn-O (IZO) thin-film transistors (TFTs) exhibiting a favorable microenvironment for electron transfer by adsorbed artificial deoxyribonucleic acid (DNA) have extraordinary potential for emerging flexible biosensor applications. Superb sensing ability to differentiate even 0.5 μL of 50 nM DNA target solution was achieved through using IZO TFTs fabricated at 280 °C. Our IZO TFT had a turn-on voltage (V(on)) of -0.8 V, on/off ratio of 6.94 × 10(5), and on-current (I(on)) value of 2.32 × 10(-6)A in pristine condition. A dry-wet method was applied to immobilize two dimensional double crossover tile based DNA nanostructures on the IZO surface, after which we observed a negative shift of the transfer curve accompanied by a significant increase in the Ion and degradation of the Von and on/off ratio. As the concentration of DNA target solution increased, variances in these parameters became increasingly apparent. The sensing mechanism based on the current evolution was attributed to the oxidation of DNA, in which the guanine nucleobase plays a key role. The sensing behavior obtained from flexible biosensors on a polymeric substrate fabricated under the identical conditions was exactly analogous. These results compare favorably with the conventional field-effect transistor based DNA sensors by demonstrating remarkable sensitivity and feasibility of flexible devices that arose from a different sensing mechanism and a low-temperature process, respectively., (© 2013 Published by Elsevier B.V.)
- Published
- 2014
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37. Comparison of surgical outcomes between papillary thyroid cancer patients treated with the Harmonic ACE scalpel and LigaSure Precise instrument during conventional thyroidectomy: a single-blind prospective randomized controlled trial.
- Author
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Kwak HY, Chae BJ, Park YG, Kim SH, Chang EY, Kim EJ, Song BJ, Jung SS, and Bae JS
- Subjects
- Adult, Aged, Carcinoma epidemiology, Carcinoma, Papillary, Comorbidity, Electrocoagulation adverse effects, Electrocoagulation methods, Female, Follow-Up Studies, Hemostasis, Surgical adverse effects, Hemostasis, Surgical methods, Humans, Hypoparathyroidism etiology, Male, Middle Aged, Postoperative Hemorrhage etiology, Prospective Studies, Single-Blind Method, Thyroid Cancer, Papillary, Thyroid Neoplasms epidemiology, Thyroidectomy adverse effects, Thyroidectomy methods, Treatment Outcome, Vocal Cord Paralysis etiology, Young Adult, Carcinoma surgery, Electrocoagulation instrumentation, Hemostasis, Surgical instrumentation, Thyroid Neoplasms surgery, Thyroidectomy instrumentation
- Abstract
Background: The aim of this study was to evaluate the safety and efficacy of thyroidectomy using the Harmonic ACE scalpel (HS) or the LigaSure Precise (LS) instrument in conventional thyroidectomy., Materials and Methods: A prospective, randomized controlled trial was performed. Between August 2011 and June 2012, 832 patients who required thyroidectomy for papillary thyroid cancer were randomized into groups treated with either the HS or the LS instrument. Operative time and surgical morbidities were analyzed., Results: A total of 320 patients (HS group, N = 164; LS instrument group, N = 156) were randomized for analysis according to the intention-to-treat principle. There were no statistically significant differences in the operative times (HS group versus LS instrument group: 71.93 ± 18.26 versus 75.15 ± 20.13; P = 0.423), postoperative transient hypoparathyroidism (13.4% versus 14.1%; P = 0.858), and permanent recurrent laryngeal nerve injuries between the two groups., Conclusions: In this study, both hemostatic devices were safe and effective in terms of postoperative results and complications without any differences., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
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38. Feasibility of sentinel lymph node biopsy in breast cancer patients clinically suspected of axillary lymph node metastasis on preoperative imaging.
- Author
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Kwak HY, Chae BJ, Bae JS, Kim EJ, Chang EY, Kim SH, Jung SS, and Song BJ
- Subjects
- Axilla, Breast Neoplasms mortality, Breast Neoplasms surgery, Carcinoma, Ductal, Breast mortality, Carcinoma, Ductal, Breast surgery, Feasibility Studies, Female, Follow-Up Studies, Humans, Lymphatic Metastasis, Middle Aged, Neoplasm Grading, Neoplasm Recurrence, Local mortality, Neoplasm Recurrence, Local surgery, Neoplasm Staging, Positron-Emission Tomography, Prognosis, Survival Rate, Ultrasonography, Mammary, Breast Neoplasms diagnosis, Carcinoma, Ductal, Breast diagnosis, Neoplasm Recurrence, Local diagnosis, Sentinel Lymph Node Biopsy
- Abstract
Background: Generally, sentinel lymph node biopsy (SLNB) is performed in patients with clinically negative axillary lymph node (LN). This study was to assess imaging techniques in axillary LN staging and to evaluate the feasibility of SLNB in patients clinically suspected of axillary LN metastasis on preoperative imaging techniques (SI)., Methods: A prospectively maintained database of 767 breast cancer patients enrolled between January 2006 and December 2009 was reviewed. All patients were offered preoperative breast ultrasound, magnetic resonance imaging, and positron emission tomography scanning. SI patients were regarded as those for whom preoperative imaging was "suspicious for axillary LN metastasis" and NSI as "non-suspicious for axillary LN metastasis" on preoperative imaging techniques. Patients were subgrouped by presence of SI and types of axillary operation, and analyzed., Results: For 323 patients who received SLNB, there was no statistically significant difference in axillary recurrence (P=0.119) between SI and NSI groups. There also was no significant difference in axillary recurrence between SLNB and axillary lymph node dissection (ALND) groups in 356 SI patients (P=0.420). The presence of axillary LN metastasis on preoperative imaging carried 82.1% sensitivity and 45.9% specificity for determining axillary LN metastasis on the final pathology., Conclusions: SLNB in SI patents is safe and feasible. Complications might be avoided by not performing ALND. Therefore, we recommend SLNB, instead of a direct ALND, even in SI patients, for interpreting the exact nodal status and avoiding unnecessary morbidity by performing ALND.
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- 2013
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39. Breast cancer after kidney transplantation: a single institution review.
- Author
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Kwak HY, Chae BJ, Bae JS, Jung SS, and Song BJ
- Subjects
- Adult, Breast Neoplasms epidemiology, Breast Neoplasms mortality, Cohort Studies, Female, Follow-Up Studies, Humans, Immunosuppressive Agents therapeutic use, Incidence, Kidney Failure, Chronic surgery, Male, Middle Aged, Neoplasm Staging, Prognosis, Registries, Survival Rate, Young Adult, Breast Neoplasms etiology, Kidney Failure, Chronic complications, Kidney Transplantation adverse effects, Postoperative Complications
- Abstract
Background: Improvements in immunosuppression have resulted in long life expectancy of kidney transplants. Unfortunately, the incidence of post-transplant malignancy (PTM) is increasing. The aim of this study was to evaluate the nature and stage-specific prognosis of post-transplant breast cancer (PTBC) compared with breast cancer in the general population, and to suggest optimal treatment strategies., Methods: A database of 2,139 consecutive kidney transplant patients was reviewed;11 of the patients developed breast cancer. These 11 PTBC cases underwent operations between 1999 and 2011. Next, 2,554 breast cancer patients treated in the same period were reviewed. Kaplan-Meier curves and the log-rank test were used to assess stage-specific survival of breast cancer in our hospital., Results: In total, 142 cases experienced post-transplant malignancy (PTM; 6.6%) and 11 (0.5%) developed PTBC. No one required an adjusted dose of immunosuppressive agent. Two stage III patients died. For all breast cancer patients, 5-year survival by stage was 97.7% for stage I, 92.9% for stage II, 78.6% for stage III, and 49.9% for stage IV. The 5-year survival for expected stage III-specific survival was 66.7% and no significant statistical difference was seen compared to that of the total breast cancer patients (P = 0.213)., Conclusions: The prognosis of PTBC was comparable to that of the general population. These results suggest that the use of immunosuppressants per se does not adversely affect breast cancer.
- Published
- 2013
- Full Text
- View/download PDF
40. Designed cyanide- and phenoxide-bridged Fe(III)Mn(III) single-molecule magnet constructed by highly blocked paramagnetic precursors.
- Author
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Cho KJ, Ryu DW, Kwak HY, Lee JW, Lee WR, Lim KS, Koh EK, Kwon YW, and Hong CS
- Subjects
- Molecular Structure, Schiff Bases chemistry, Cyanides chemistry, Ferric Compounds chemistry, Magnets chemistry, Manganese chemistry
- Abstract
A tetranuclear Fe(III)(2)Mn(III)(2) compound was prepared using highly blocked precursors. The well-isolated molecular entity associated with appropriate magnetic anisotropy allows for single-molecule magnet behavior.
- Published
- 2012
- Full Text
- View/download PDF
41. Early surgical repair of acute complete rupture of the proximal hamstring tendons.
- Author
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Kwak HY, Bae SW, Choi YS, and Jang MS
- Subjects
- Acute Disease, Adolescent, Adult, Humans, Male, Rupture, Tendon Injuries diagnosis, Thigh, Young Adult, Football injuries, Martial Arts injuries, Tendon Injuries surgery
- Abstract
Hamstring injuries are common forms of muscle strains in athletes but a complete rupture of a proximal hamstring origin is rare. Often there is a considerable delay in diagnosis and stringent treatment because of its rarity, difficulty in clinical diagnosis, and initial attempts of conservative care. We report two cases of acute complete rupture of the proximal hamstring tendons treated with early surgical repair. The diagnosis and treatment of this unusual injury are discussed.
- Published
- 2011
- Full Text
- View/download PDF
42. Synthesis, characterization, luminescence and defect centres in CaYAl3O7:Eu3+ red phosphor.
- Author
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Singh V, Watanabe S, Rao TK, and Kwak HY
- Subjects
- Electron Spin Resonance Spectroscopy, Luminescence, Microscopy, Electron, Scanning, Spectroscopy, Fourier Transform Infrared, X-Ray Diffraction, Europium chemistry, Phosphorus chemistry
- Abstract
CaYAl(3)O(7):Eu(3+) phosphor was prepared at furnace temperatures as low as 550°C by a solution combustion method. The formation of crystalline CaYAl(3)O(7):Eu(3+) was confirmed by powder X-Ray diffraction pattern. The prepared phosphor was characterized by SEM, FT-IR and photoluminescence techniques. Photoluminescence measurements indicated that emission spectrum is dominated by the red peak located at 618 nm due to the (5)D(0)-(7)F(2) electric dipole transition of Eu(3+) ions. Electron Spin Resonance (ESR) studies were carried out to identify the centres responsible for the thermoluminescence (TL) peaks. Room temperature ESR spectrum of irradiated phosphor appears to be a superposition of two distinct centres. One of the centres (centre I) with principal g-value 2.0126 is identified as an O(-) ion while centre II with an isotropic g-factor 2.0060 is assigned to an F(+) centre (singly ionized oxygen vacancy). An additional defect centre is observed during thermal annealing experiments and this centre (assigned to F(+) centre) seems to originate from an F centre (oxygen vacancy with two electrons). The F(+) centre appears to correlate with the observed high temperature TL peak in CaYAl(3)O(7):Eu(3+) phosphor.
- Published
- 2011
- Full Text
- View/download PDF
43. Anti-pruritic effect of baicalin and its metabolites, baicalein and oroxylin A, in mice.
- Author
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Trinh HT, Joh EH, Kwak HY, Baek NI, and Kim DH
- Subjects
- Animals, Anti-Bacterial Agents administration & dosage, Antipruritics analysis, Antipruritics metabolism, Feces microbiology, Flavanones analysis, Flavonoids analysis, Flavonoids metabolism, Guinea Pigs, Histamine administration & dosage, Histamine Antagonists analysis, Histamine Antagonists metabolism, Intestines microbiology, Male, Mice, Mice, Inbred BALB C, Mice, Inbred ICR, Phytotherapy, Scutellaria baicalensis chemistry, Scutellaria baicalensis metabolism, Streptomycin administration & dosage, Tetracycline administration & dosage, Antipruritics therapeutic use, Flavanones therapeutic use, Flavonoids therapeutic use, Histamine Antagonists therapeutic use, Pruritus drug therapy
- Abstract
Aim: To explore whether intestinal microflora plays a role in anti-pruritic activity of baicalin, a main constituent of the rhizome of Scutellaria baicalensis (SB)., Methods: Baicalin was anaerobically incubated with human fecal microflora, and its metabolites, baicalein and oroxylin A, were isolated. The inhibitory effect of baicalin and its metabolites was accessed in histamine- or compound 48/80-induced scratching behavior in mice., Results: Baicalin was metabolized to baicalein and oroxylin A, with metabolic activities of 40.2+/-26.2 and 1.2+/-1.1 nmol.h(-1).mg(-1) wet weight of human fecal microflora, respectively. Baicalin (20, 50 mg/kg) showed more potent inhibitory effect on histamine-induced scratching behavior when orally administered than intraperitoneally. In contrast, baicalein and oroxylin A had more potent inhibitory effect when the intraperitoneally administered. The anti-scratching behavior activity of oral baicalin and its metabolites was in proportion to their inhibition on histamine-induced increase of vascular permeability with oroxylin A more potent than baicalein and baicalin. In Magnus test using guinea pig ileum, oroxylin A is more potent than baicalein and baicalin in inhibition of histamine-induced contraction. The anti-scratching behavioral effect of oral baicalin was significantly reduced when oral antibiotics were simultaneously administered, whereas the effect of baicalein and oroxylin A were not affected., Conclusion: Oral baicalin may be metabolized by intestinal microflora into baicalein and oroxylin A, which ameliorate pruritic reactions through anti-histamine action.
- Published
- 2010
- Full Text
- View/download PDF
44. Cyanide-bridged Fe(III)-Mn(III) bimetallic systems assembled from the fac-Fe tricyanide and Mn Schiff bases: structures, magnetic properties, and density functional theory calculations.
- Author
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Kwak HY, Ryu DW, Lee JW, Yoon JH, Kim HC, Koh EK, Krinsky J, and Hong CS
- Subjects
- Models, Molecular, Molecular Conformation, Organometallic Compounds chemical synthesis, Schiff Bases chemistry, Iron chemistry, Magnetics, Manganese chemistry, Nitriles chemistry, Organometallic Compounds chemistry, Quantum Theory
- Abstract
Reaction of [(Tp)Fe(CN)(3)](-) [Tp = hydrotris(pyrazolyl)borate] with respective Mn(III) Schiff bases led to the formation of four dimeric molecules, [(Tp)Fe(CN)(3)][Mn(1-napen)(H(2)O)].MeCN.4H(2)O [1; 1-napen = N,N'-ethylenebis(2-hydroxy-1-naphthylideneiminato) dianion], [(Tp)Fe(CN)(3)][Mn(5-Clsalen)(H(2)O)] [2; 5-Clsalcy = N,N'-(trans-1,2-cyclohexanediylethylene)bis(5-chlorosalicylideneiminato) dianion], [(Tp)Fe(CN)(3)][Mn(2-acnapen)(MeOH)].MeOH [3; 2-acnapen = N,N'-ethylenebis(1-hydroxy-2-acetonaphthylideneiminato) dianion], [(Tp)Fe(CN)(3)][Mn(3-MeOsalen)(H(2)O)] [4; 3-MeOsalen = N,N'-ethylenebis(3-methoxysalicylideneiminato) dianion], and a one-dimensional (1D) zigzag chain [(Tp)Fe(CN)(3)][Mn(2-acnapen)].H(2)O (5). The dimers contain multiple intermolecular interactions such as hydrogen bonds, face-to-face pi-pi contacts, and edge-to-face CH-pi forces, raising molecular dimensions from one-dimensional (1D) up to three-dimensional (3D) arrays, whereas there are no pi-pi stacking interactions in the 1D chain compound. Magnetic measurements reveal that ferromagnetic couplings are obviously operative between Mn(III) and Fe(III) spin centers transmitted by CN bridges for 1-3 and 5, and antiferromagnetic interactions are however unexpectedly present in 4. On the basis of the proper spin Hamiltonians, magnetic exchange couplings are estimated to be in the span from 1.79 to 7.48 cm(-1) for the ferromagnetically coupled systems and -1.40 cm (-1) for the antiferromagnetic dimer. A slow magnetic relaxation is tangible in 5, which is in connection with isolated chains devoid of any intermolecular noncovalent interactions. Density Functional Theory (DFT) calculations and comparison of structural parameters suggest that the observed magnetic behaviors are mainly associated with the bending of the Mn-N[triple bond]C angle in the bridging pathway.
- Published
- 2010
- Full Text
- View/download PDF
45. Sterols isolated from Nuruk (Rhizopus oryzae KSD-815) inhibit the migration of cancer cells.
- Author
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Lee DY, Lee SJ, Kwak HY, Jung L, Heo J, Hong S, Kim GW, and Baek NI
- Subjects
- Breast Neoplasms pathology, Breast Neoplasms physiopathology, Cell Line, Tumor, Ergosterol analogs & derivatives, Ergosterol chemistry, Ergosterol isolation & purification, Ergosterol pharmacology, Female, Humans, Magnetic Resonance Spectroscopy, Mass Spectrometry, Molecular Structure, Rhizopus isolation & purification, Sitosterols chemistry, Sitosterols isolation & purification, Sitosterols pharmacology, Spectrophotometry, Infrared, Sterols chemistry, Stigmasterol analogs & derivatives, Stigmasterol chemistry, Stigmasterol isolation & purification, Stigmasterol pharmacology, Breast Neoplasms drug therapy, Cell Movement drug effects, Edible Grain microbiology, Food Microbiology, Rhizopus chemistry, Sterols isolation & purification, Sterols pharmacology
- Abstract
An activity-guided fractionation method was used to isolate anticancer components from Nuruk (Rhizopus oryzae KSD-815:KSD-815). Dried powder of KSD-815 was extracted with 80% methanol and partitioned successively using nhexane, ethyl acetate, n-butanol, and water. The n-hexane and n-butanol fractions showed a strong antimigratory effect on human cancer cells. Both of these fractions were subjected to separation and purification procedures using silica gel, octadecyl silica gel, and Sephadex LH-20 column chromatographies to afford four purified compounds. These were identified as ergosterol peroxide (1), stigmast- 5-en-3beta,7beta-diol (2), ergosta-7,22-dien-3beta,5alpha,6beta,9alpha-tetraol (3), and daucosterol (4), respectively, by spectroscopic methods such as nuclear magnetic resonance spectrometry, mass spectrometry, and infrared spectroscopy, and comparison with those in the literature. Compounds 1-4 were isolated from KSD-815 for the first time. Compounds 1 and 4 inhibited the migration of MDA-MB-231 cells at concentrations lower than 20 micronM.
- Published
- 2009
- Full Text
- View/download PDF
46. Cyanide-bridged Fe(III)-Mn(III) bimetallic complexes with dimeric and chain structures constructed from a newly made mer-Fe tricyanide: structures and magnetic properties.
- Author
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Kim JI, Kwak HY, Yoon JH, Ryu DW, Yoo IY, Yang N, Cho BK, Park JG, Lee H, and Hong CS
- Abstract
Four cyanide-linked Fe(III)-Mn(III) complexes were prepared by reacting Mn Schiff bases with a new molecular precursor (PPh(4))[Fe(qcq)(CN)(3)] [1; qcq = 8-(2-quinolinecarboxamido)quinoline anion]. They include a dimeric molecule, [Fe(qcq)(CN)(3)][Mn(3-MeOsalen)(H(2)O)] x 2 H(2)O [2 x 2 H(2)O; 3-MeOsalen = N,N'-ethylenebis(3-methoxysalicylideneiminato) dianion], and three 1D zigzag chains, [Fe(qcq)(CN)(3)][Mn(5-Clsalen)] x 3 H(2)O [3 x 2 MeOH; 5-Clsalen = N,N'-ethylenebis(5-chlorosalicylideneiminato) dianion], [Fe(qcq)(CN)(3)][Mn(5-Brsalen)] x 2 MeOH [4 x 2 MeOH; 5-Brsalen = N,N'-ethylenebis(5-bromosalicylideneiminato) dianion], and Fe(qcq)(CN)(3)][Mn(salen)].MeCN x H(2)O [5 x MeCN; salen = N,N'-ethylenebis(salicylideneiminato) dianion]. The complexes consist of extensive hydrogen bonding and pi-pi stacking interactions, generating multidimensional structures. Magnetic studies demonstrate that antiferromagnetic couplings are operative between Fe(III) and Mn(III) centers bridged by cyanide ligands. On the basis of an infinite chain model, magnetic coupling parameters of 2-5 range from -9.3 to -14.1 cm(-1). A long-range order is observed at 2.3 K for 3 and 2.2 K for 4, while compound 5 shows spin glass behavior possibly coupled with magnetic ordering.
- Published
- 2009
- Full Text
- View/download PDF
47. Pulse oximetry-induced third-degree burn in recovery room.
- Author
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Kwak HY and Kim JI
- Subjects
- Humans, Male, Recovery Room, Young Adult, Burns etiology, Oximetry adverse effects, Oximetry instrumentation
- Published
- 2009
- Full Text
- View/download PDF
48. Syntheses, crystal structures and magnetic properties of cyano- and phenoxide-bridged Fe(iii)Mn(iii) tetramers containing fac-Fe(iii) tricyanides and Mn(iii) Schiff bases.
- Author
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Kwak HY, Ryu DW, Kim HC, Koh EK, Cho BK, and Hong CS
- Subjects
- Crystallography, X-Ray, Schiff Bases chemistry, Cyanides chemistry, Ferric Compounds chemistry, Magnetics, Manganese chemistry
- Abstract
Three cyanide-linked Fe(iii)Mn(iii) bimetallic clusters, [(Tp)Fe(CN)(3)](2)[Mn(acphen)](2) [; acphen = N,N'-ethylenebis(2-hydroxyacetophenylideneiminato) dianion], [(Tp)Fe(CN)(3)](2)[Mn(5-Bracphen)](2) [; 5-Bracphen = N,N'-ethylenebis(5-bromo-2-hydroxyacetophenylideneiminato) dianion], and [(Tp)Fe(CN)(3)](2)[Mn(salen)](2).6H(2)O [; salen = N,N'-ethylenebis(salicylidineiminato) dianion], were prepared by self-assembling a facial [(Tp)Fe(CN)(3)](-) [Tp = hydrotris(pyrazolyl)borate] precursor and respective Mn(iii) Schiff bases. X-Ray crystal structure analyses revealed that each complex is composed of a central Mn(iii) dimer doubly linked by phenoxides of the tetradentate N(2)O(2) Schiff bases and the terminal [(Tp)Fe(CN)(3)](-) groups connecting to the center through cyanides. Using the spin Hamiltonian H = -2J(1)(S(Fe1).S(Mn1) + S(Mn1a).S(Fe1a)) - 2J(2)(S(Mn1).S(Mn1a)), where J(1) stands for the exchange coupling constant between Fe(iii) (S(Fe) = 1/2) and Mn(iii) (S(Mn) = 2) through cyanides and J(2) between Mn(iii) ions via phenoxides, the best fits corresponded to J(1) = 2.61 cm(-1) and J(2) = 0.85 cm(-1) for , J(1) = 2.50 cm(-1) and J(2) = 1.30 cm(-1) for , and J(1) = -2.15 cm(-1) and J(2) = 0.55 cm(-1) for . The phenoxide routes transmit ferromagnetic interactions in all cases, while ferromagnetic or antiferromagnetic couplings occur through the cyanide linkage. Although the geometric parameters relevant to the magnetic Fe-C[triple bond, length as m-dash]N-Mn pathways are analogous to each other their magnetic natures are varied across the compounds, which supports that a degree of orbital overlap is quite sensitive to a subtle structural change in the present system.
- Published
- 2009
- Full Text
- View/download PDF
49. Intermolecular contact-tuned magnetic nature in one-dimensional 3d-5d bimetallic systems: from a metamagnet to a single-chain magnet.
- Author
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Choi SW, Kwak HY, Yoon JH, Kim HC, Koh EK, and Hong CS
- Subjects
- 2,2'-Dipyridyl analogs & derivatives, 2,2'-Dipyridyl chemistry, Amines chemistry, Anisotropy, Cyanides chemistry, Cyclohexanes chemistry, Models, Molecular, Naphthalenes chemistry, Organometallic Compounds chemical synthesis, Magnetics, Manganese chemistry, Organometallic Compounds chemistry, Tungsten chemistry
- Abstract
Assembling [W(CN) 6(bpy)] (-) and magnetic anisotropic Mn Schiff bases produced two Mn (III)(3d)-W (V)(5d) bimetallic chains. Modulation of the types and degrees of interchain pi-pi interactions in the one-dimensional coordination polymers leads to the variation of the magnetic behavior from a metamagnetic character to a single-chain magnet property.
- Published
- 2008
- Full Text
- View/download PDF
50. beta-catenin regulates multiple steps of RNA metabolism as revealed by the RNA aptamer in colon cancer cells.
- Author
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Lee HK, Kwak HY, Hur J, Kim IA, Yang JS, Park MW, Yu J, and Jeong S
- Subjects
- Adenocarcinoma metabolism, Alternative Splicing, Animals, Aptamers, Nucleotide genetics, Colonic Neoplasms metabolism, Cyclin D1 biosynthesis, Cyclin D1 genetics, Cyclooxygenase 2 biosynthesis, Cyclooxygenase 2 genetics, HCT116 Cells, Humans, Mice, NIH 3T3 Cells, RNA, Messenger biosynthesis, RNA, Messenger genetics, RNA, Messenger metabolism, RNA, Neoplasm genetics, TCF Transcription Factors metabolism, Transcription Factor 7-Like 2 Protein, beta Catenin genetics, beta Catenin metabolism, Adenocarcinoma genetics, Aptamers, Nucleotide metabolism, Colonic Neoplasms genetics, RNA, Neoplasm metabolism, beta Catenin antagonists & inhibitors
- Abstract
Nuclear beta-catenin forms a transcription complex with TCF-4, which is implicated in colon cancer development and progression. Recently, we and others have shown that beta-catenin could be a regulator of RNA splicing and it also stabilizes the cyclooxygenase-2 (COX-2) mRNA. Here, we further explored the role of beta-catenin in the RNA metabolism in colon cancer cells. To specifically modulate the subcellular functions of beta-catenin, we expressed the RNA aptamer in the form of RNA intramers with unique cellular localizations. The nucleus-expressed RNA intramer proved to be effective in reducing the protein-protein interaction between beta-catenin and TCF-4, thus shown to be a specific regulator of beta-catenin-activated transcription. It could also regulate the alternative splicing of E1A minigene in diverse colon cancer cell lines. In addition, we tested whether beta-catenin could stabilize any other mRNAs and found that cyclin D1 mRNA was also bound and stabilized by beta-catenin. Significantly, the cytoplasm-expressed RNA intramer reverted the beta-catenin-induced COX-2 and cyclin D1 mRNA stabilization. We show here that beta-catenin regulated multiple steps of RNA metabolism in colon cancer cells and might be the protein factor coordinating RNA metabolism. We suggest that the RNA intramers could provide useful ways for inhibiting beta-catenin-mediated transcription and RNA metabolism, which might further enhance the antitumorigenic effects of these molecules in colon cancer cells.
- Published
- 2007
- Full Text
- View/download PDF
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