1.Quantitative Evaluation of Hepatic Steatosis Using Advanced Imaging Techniques: Focusing on New Quantitative Ultrasound Techniques
Junghoan PARK ; Jeong Min LEE ; Gunwoo LEE ; Sun Kyung JEON ; Ijin JOO
Korean Journal of Radiology 2022;23(1):13-29
Nonalcoholic fatty liver disease, characterized by excessive accumulation of fat in the liver, is the most common chronic liver disease worldwide. The current standard for the detection of hepatic steatosis is liver biopsy; however, it is limited by invasiveness and sampling errors. Accordingly, MR spectroscopy and proton density fat fraction obtained with MRI have been accepted as non-invasive modalities for quantifying hepatic steatosis. Recently, various quantitative ultrasonography techniques have been developed and validated for the quantification of hepatic steatosis. These techniques measure various acoustic parameters, including attenuation coefficient, backscatter coefficient and speckle statistics, speed of sound, and shear wave elastography metrics. In this article, we introduce several representative quantitative ultrasonography techniques and their diagnostic value for the detection of hepatic steatosis.
2.Effects of cementless fixation of implant prosthesis: A finite element study
Hyeonjong LEE ; Soyeon PARK ; Kung Rock KWON ; Gunwoo NOH
The Journal of Advanced Prosthodontics 2019;11(6):341-349
PURPOSE: A novel retentive type of implant prosthesis that does not require the use of cement or screw holes has been introduced; however, there are few reports examining the biomechanical aspects of this novel implant. This study aimed to evaluate the biomechanical features of cementless fixation (CLF) implant prostheses.MATERIALS AND METHODS: The test groups of three variations of CLF implant prostheses and a control group of conventional cement-retained (CR) prosthesis were designed three-dimensionally for finite element analysis. The test groups were divided according to the abutment shape and the relining strategy on the inner surface of the implant crown as follows; resin-air hole-full (RAF), resin-air hole (RA), and resin-no air hole (RNA). The von Mises stress and principal stress were used to evaluate the stress values and distributions of the implant components. Contact open values were calculated to analyze the gap formation of the contact surfaces at the abutment-resin and abutment-implant interfaces. The micro-strain values were evaluated for the surrounding bone.RESULTS: Values reflecting the maximum stress on the abutment were as follows (in MPa): RAF, 25.6; RA, 23.4; RNA, 20.0; and CR, 15.8. The value of gap formation was measured from 0.88 to 1.19 µm at the abutmentresin interface and 24.4 to 24.7 µm at the abutment-implant interface. The strain distribution was similar in all cases.CONCLUSION: CLF had no disadvantages in terms of the biomechanical features compared with conventional CR implant prosthesis and could be successfully applied for implant prosthesis.
Crowns
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Finite Element Analysis
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Prostheses and Implants
;
RNA
3.The Effectiveness of Ferritin as a Contrast Agent for Cell Tracking MRI in Mouse Cancer Models.
Chan Wha LEE ; Sun Il CHOI ; Sang Jin LEE ; Young Taek OH ; Gunwoo PARK ; Na Yeon PARK ; Kyoung Ah YOON ; Sunshin KIM ; Daehong KIM ; Yun Hee KIM ; Jin Suck SUH
Yonsei Medical Journal 2017;58(1):51-58
PURPOSE: We aimed to investigate the effectiveness of ferritin as a contrast agent and a potential reporter gene for tracking tumor cells or macrophages in mouse cancer models. MATERIALS AND METHODS: Adenoviral human ferritin heavy chain (Ad-hFTH) was administrated to orthotopic glioma models and subcutaneous colon cancer mouse models using U87MG and HCT116 cells, respectively. Brain MR images were acquired before and daily for up to 6 days after the intracranial injection of Ad-hFTH. In the HCT116 tumor model, MR examinations were performed before and at 6, 24, and 48 h after intratumoral injection of Ad-hFTH, as well as before and every two days after intravenous injection of ferritin-labeled macrophages. The contrast effect of ferritin in vitro was measured by MR imaging of cell pellets. MRI examinations using a 7T MR scanner comprised a T1-weighted (T1w) spin-echo sequence, T2-weighted (T2w) relaxation enhancement sequence, and T2*-weighted (T2*w) fast low angle shot sequence. RESULTS: Cell pellet imaging of Ad-hFTH in vitro showed a strong negatively enhanced contrast in T2w and T2*w images, presenting with darker signal intensity in high concentrations of Fe. T2w images of glioma and subcutaneous HCT116 tumor models showed a dark signal intensity around or within the Ad-hFTH tumor, which was distinct with time and apparent in T2*w images. After injection of ferritin-labeled macrophages, negative contrast enhancement was identified within the tumor. CONCLUSION: Ferritin could be a good candidate as an endogenous MR contrast agent and a potential reporter gene that is capable of maintaining cell labeling stability and cellular safety.
Animals
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Brain Neoplasms/*diagnostic imaging/pathology
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Cell Line, Tumor
;
Cell Tracking/*methods
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Colonic Neoplasms/*diagnostic imaging/pathology
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*Contrast Media/administration & dosage
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Disease Models, Animal
;
Female
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*Ferritins/administration & dosage
;
Genes, Reporter
;
Glioma/*diagnostic imaging/pathology
;
Humans
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Injections, Intravenous
;
Macrophages
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Magnetic Resonance Imaging/*methods
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Male
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Mice
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Neoplasm Transplantation
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Skin Neoplasms/*diagnostic imaging/pathology
;
Time Factors
4.Papular Mucinosis in a Renal Transplantation Recipient.
Jae Keun PARK ; Mi Yeon YU ; Gunwoo KOO ; Joo Hee KWAK ; Jung Hoon LEE ; In Sub JUNG ; Hyunwoo OH ; Joon Sung PARK
The Journal of the Korean Society for Transplantation 2014;28(4):236-240
Papular mucinosis (PM, scleromyxoedema) is a rare dermatologic disease. It is histologically characterized by a focal dermal deposit of mucin within the skin. Although PM is accepted as an idiopathic disease in most cases, some authors argued that it may be a cutaneous manifestation of a systemic disease. Here, we describe a 68-year-old male kidney transplantation recipient with a complaint of intractable itching sensation on the forehead. We diagnosed the skin lesions as PM, which were improved after cyclosporine dose reduction.
Aged
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Cyclosporine
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Forehead
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Humans
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Kidney Transplantation*
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Male
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Mucins
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Pruritus
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Scleromyxedema*
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Sensation
;
Skin
5.Deep learning-based automated quantification of the hepatorenal index for evaluation of fatty liver by ultrasonography
Dong Ik CHA ; Tae Wook KANG ; Ji Hye MIN ; Ijin JOO ; Dong Hyun SINN ; Sang Yun HA ; Kyunga KIM ; Gunwoo LEE ; Jonghyon YI
Ultrasonography 2021;40(4):565-574
Purpose:
The aim of this study was to develop and validate a fully-automatic quantification of the hepatorenal index (HRI) calculated by a deep convolutional neural network (DCNN) comparable to the interpretations of radiologists experienced in ultrasound (US) imaging.
Methods:
In this retrospective analysis, DCNN-based organ segmentation with Gaussian mixture modeling for automated quantification of the HRI was developed using abdominal US images from a previous study. For validation, 294 patients who underwent abdominal US examination before living-donor liver transplantation were selected. Interobserver agreement for the measured brightness of the liver and kidney and the calculated HRI were analyzed between two board-certified radiologists and DCNN using intraclass correlation coefficients (ICCs).
Results:
Most patients had normal (n=95) or mild (n=198) fatty liver. The ICCs of hepatic and renal brightness measurements and the calculated HRI between the two radiologists were 0.892 (95% confidence interval [CI], 0.866 to 0.913), 0.898 (95% CI, 0.873 to 0.918), and 0.681 (95% CI, 0.615 to 0.738) for the first session and 0.920 (95% CI, 0.901 to 0.936), 0.874 (95% CI, 0.844 to 0.898), and 0.579 (95% CI, 0.497 to 0.650) for the second session, respectively; the results ranged from moderate to excellent agreement. Using the same task, the ICCs of the hepatic and renal measurements and the calculated HRI between the average values of the two radiologists and DCNN were 0.919 (95% CI, 0.899 to 0.935), 0.916 (95% CI, 0.895 to 0.932), and 0.734 (95% CI, 0.676 to 0.782), respectively, showing high to excellent agreement.
Conclusion
Automated quantification of HRI using DCNN can yield HRI measurements similar to those obtained by experienced radiologists in patients with normal or mild fatty liver.
6.Quality Indicators for Evaluating the Health Care of Patients with Rheumatoid Arthritis: a Korean Expert Consensus
Mi Ryoung SEO ; Gunwoo KIM ; Ki Won MOON ; Yoon-Kyoung SUNG ; Jong Jin YOO ; Chong-Hyeon YOON ; Eun Bong LEE ; Jisoo LEE ; Eun Ha KANG ; Hyungjin KIM ; Eun-Jung PARK ; Wan-Sik UHM ; Myeung Su LEE ; Seung-Won LEE ; Byoong Yong CHOI ; Seung-Jae HONG ; Han Joo BAEK
Journal of Korean Medical Science 2021;36(17):e109-
Background:
There is increasing interest in the quality of health care and considerable efforts are being made to improve it. Rheumatoid arthritis (RA) is a disease that can result in favorable outcomes when appropriate diagnosis and treatment are provided. However, several studies have shown that RA is often managed inappropriately. Therefore, the Korean College of Rheumatology aimed to develop quality indicators (QIs) to evaluate and improve the health care of patients with RA.
Methods:
Preliminary QIs were derived based on the existing guidelines and QIs for RA. The final QIs were determined through two separate consensus meetings of experts. The consensus was achieved through a panel of experts who voted using the modified Delphi method.
Results:
Fourteen final QIs were selected among 70 preliminary QIs. These included early referral to and regular follow-up with a rheumatologist, radiographs of the hands and feet, early initiation and maintenance of disease-modifying anti-rheumatic drug (DMARD) therapy, periodic assessment of disease activity, screening for drug safety and comorbidities,including viral hepatitis and tuberculosis before biologic DMARD therapy, periodic laboratory testing, supplementation with folic acid, assessment of the risk for cervical spine instability before general anesthesia, patient education, and specialized nurse.
Conclusion
These QIs can be used to assess and improve the quality of health care for patients with RA.
7.Quality Indicators for Evaluating the Health Care of Patients with Rheumatoid Arthritis: a Korean Expert Consensus
Mi Ryoung SEO ; Gunwoo KIM ; Ki Won MOON ; Yoon-Kyoung SUNG ; Jong Jin YOO ; Chong-Hyeon YOON ; Eun Bong LEE ; Jisoo LEE ; Eun Ha KANG ; Hyungjin KIM ; Eun-Jung PARK ; Wan-Sik UHM ; Myeung Su LEE ; Seung-Won LEE ; Byoong Yong CHOI ; Seung-Jae HONG ; Han Joo BAEK
Journal of Korean Medical Science 2021;36(17):e109-
Background:
There is increasing interest in the quality of health care and considerable efforts are being made to improve it. Rheumatoid arthritis (RA) is a disease that can result in favorable outcomes when appropriate diagnosis and treatment are provided. However, several studies have shown that RA is often managed inappropriately. Therefore, the Korean College of Rheumatology aimed to develop quality indicators (QIs) to evaluate and improve the health care of patients with RA.
Methods:
Preliminary QIs were derived based on the existing guidelines and QIs for RA. The final QIs were determined through two separate consensus meetings of experts. The consensus was achieved through a panel of experts who voted using the modified Delphi method.
Results:
Fourteen final QIs were selected among 70 preliminary QIs. These included early referral to and regular follow-up with a rheumatologist, radiographs of the hands and feet, early initiation and maintenance of disease-modifying anti-rheumatic drug (DMARD) therapy, periodic assessment of disease activity, screening for drug safety and comorbidities,including viral hepatitis and tuberculosis before biologic DMARD therapy, periodic laboratory testing, supplementation with folic acid, assessment of the risk for cervical spine instability before general anesthesia, patient education, and specialized nurse.
Conclusion
These QIs can be used to assess and improve the quality of health care for patients with RA.
8.Recommendations for the management of patients with systemic rheumatic diseases during the coronavirus disease pandemic
Mi Ryoung SEO ; Ji-Won KIM ; Eun-Jung PARK ; Seung Min JUNG ; Yoon-Kyoung SUNG ; Hyungjin KIM ; Gunwoo KIM ; Hyun-Sook KIM ; Myeung-Su LEE ; Jisoo LEE ; Ji An HUR ; Bum Sik CHIN ; Joong Sik EOM ; Han Joo BAEK ;
The Korean Journal of Internal Medicine 2020;35(6):1317-1332
Patients with systemic rheumatic diseases (SRD) are vulnerable for coronavirus disease (COVID-19). The Korean College of Rheumatology recognized the urgent need to develop recommendations for rheumatologists and other physicians to manage patients with SRD during the COVID-19 pandemic. The working group was organized and was responsible for selecting key health questions, searching and reviewing the available literature, and formulating statements. The appropriateness of the statements was evaluated by voting panels using the modified Delphi method. Four general principles and thirteen individual recommendations were finalized through expert consensus based on the available evidence. The recommendations included preventive measures against COVID-19, medicinal treatment for stable or active SRD patients without COVID-19, medicinal treatment for SRD patients with COVID-19, and patient evaluation and monitoring. Medicinal treatments were categorized according to the status with respect to both COVID-19 and SRD. These recommendations should serve as a reference for individualized treatment for patients with SRD. As new evidence is emerging, an immediate update will be required.
9.Recommendations for the Management of Patients With Systemic Rheumatic Diseases During the Coronavirus Disease Pandemic
Mi Ryoung SEO ; Ji-Won KIM ; Eun-Jung PARK ; Seung Min JUNG ; Yoon-Kyoung SUNG ; Hyungjin KIM ; Gunwoo KIM ; Hyun-Sook KIM ; Myeung-Su LEE ; Jisoo LEE ; Jian HUR ; Bum Sik CHIN ; Joong Sik EOM ; Han Joo BAEK ;
Journal of Rheumatic Diseases 2020;27(4):218-232
Patients with systemic rheumatic diseases (SRD) are vulnerable for coronavirus disease (COVID-19). The Korean College of Rheumatology recognized the urgent need to develop recommendations for rheumatologists and other physicians to manage patients with SRD during the COVID-19 pandemic. The working group was organized and was responsible for selecting key health questions, searching and reviewing the available literature, and formulating statements. The appropriateness of the statements was evaluated by voting panels using the modified Delphi method. Four general principles and thirteen individual recommendations were finalized through expert consensus based on the available evidence. The recommendations included preventive measures against COVID-19, medicinal treatment for stable or active SRD patients without COVID-19, medicinal treatment for SRD patients with COVID-19, and patient evaluation and monitoring. Medicinal treatments were categorized according to the status with respect to both COVID-19 and SRD. These recommendations should serve as a reference for individualized treatment for patients with SRD. As new evidence is emerging, an immediate update will be required.
10.Preclinical development of a humanized neutralizing antibody targeting HGF.
Hyori KIM ; Sung Hee HONG ; Jung Yong KIM ; In Chull KIM ; Young Whan PARK ; Song Jae LEE ; Seong Won SONG ; Jung Ju KIM ; Gunwoo PARK ; Tae Min KIM ; Yun Hee KIM ; Jong Bae PARK ; Junho CHUNG ; In Hoo KIM
Experimental & Molecular Medicine 2017;49(3):e309-
Hepatocyte growth factor (HGF) and its receptor, cMET, play critical roles in cell proliferation, angiogenesis and invasion in a wide variety of cancers. We therefore examined the anti-tumor activity of the humanized monoclonal anti-HGF antibody, YYB-101, in nude mice bearing human glioblastoma xenografts as a single agent or in combination with temozolomide. HGF neutralization, The extracellular signal-related kinases 1 and 2 (ERK1/2) phosphorylation, and HGF-induced scattering were assessed in HGF-expressing cell lines treated with YYB-101. To support clinical development, we also evaluated the preclinical pharmacokinetics and toxicokinetics in cynomolgus monkeys, and human and cynomolgus monkey tissue was stained with YYB-101 to test tissue cross-reactivity. We found that YYB-101 inhibited cMET activation in vitro and suppressed tumor growth in the orthotopic mouse model of human glioblastoma. Combination treatment with YYB-101 and temozolomide decreased tumor growth and increased overall survival compared with the effects of either agent alone. Five cancer-related genes (TMEM119, FST, RSPO3, ROS1 and NBL1) were overexpressed in YYB-101-treated mice that showed tumor regrowth. In the tissue cross-reactivity assay, critical cross-reactivity was not observed. The terminal elimination half-life was 21.7 days. Taken together, the in vitro and in vivo data demonstrated the anti-tumor efficacy of YYB-101, which appeared to be mediated by blocking the HGF/cMET interaction. The preclinical pharmacokinetics, toxicokinetics and tissue cross-reactivity data support the clinical development of YYB-101 for advanced cancer.
Animals
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Antibodies, Neutralizing*
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Cell Line
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Cell Proliferation
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Glioblastoma
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Half-Life
;
Hepatocyte Growth Factor
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Heterografts
;
Humans*
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In Vitro Techniques
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Macaca fascicularis
;
Mice
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Mice, Nude
;
Pharmacokinetics
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Phosphorylation
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Phosphotransferases
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Toxicokinetics