1.Force and moment analysis of clear aligners: Impact of material properties and design on premolar rotation
Dong-Woo KIM ; Hyun-Jun LEE ; Ki Beom KIM ; Sung-Hun KIM ; Seong-Sik KIM ; Soo-Byung PARK ; Youn-Kyung CHOI ; Yong-Il KIM
The Korean Journal of Orthodontics 2025;55(3):212-223
Objective:
To quantitatively analyze and compare the forces and moments generated by thermoformed polyethylene terephthalate glycol (PETG) and direct-printed TC-85 clear aligners (CAs), with various margin designs, during premolar rotation.
Methods:
In total, 132 CAs were fabricated and divided into four groups (n = 33 per group). Group C consisted of thermoformed PETG aligners with a 2 mm gingival margin. Group E comprised direct-printed TC-85 aligners with equi-gingival margin, whereas Group G utilized direct-printed TC-85 aligners with 2 mm gingival margins.Finally, Group T featured direct-printed TC-85 aligners with an additional 1 mm thickness at the mesial embrasure. The forces and moments were measured using a 6-axis force/moment transducer at 2°, 3°, and 4° of rotation. All measurements were conducted at 37°C to simulate intraoral conditions. Forces were measured in the buccolingual, anteroposterior, and vertical directions, while moments were measured in the mesiodistal, buccolingual, and rotational planes.
Results:
The PETG aligners (Group C) showed significantly increased buccal and posterior force across the rotation angles (P < 0.05), whereas the intrusive force remained consistent. In contrast, the TC-85 aligners maintained consistent forces across all rotation angles.Direct-printed aligners demonstrated significantly lower intrusive forces than PETG aligners (P < 0.001). Group T exhibited reduced unwanted forces while maintaining effective rotational moments. Furthermore, all direct-printed aligners showed more predictable force delivery patterns than thermoformed aligners.
Conclusions
Direct-printed TC-85 aligners demonstrated superior force consistency and reduced unwanted side effects compared with traditional PETG aligners. Although marginal design modifications did not significantly improve rotational efficiency, they effectively reduced unwanted intrusive forces.
2.Human induced pluripotent stem cell-cardiomyocytes for cardiotoxicity assessment: a comparative study of arrhythmiainducing drugs with multi-electrode array analysis
Na Kyeong PARK ; Yun-Gwi PARK ; Ji-Hee CHOI ; Hyung Kyu CHOI ; Sung-Hwan MOON ; Soon-Jung PARK ; Seong Woo CHOI
The Korean Journal of Physiology and Pharmacology 2025;29(2):257-269
Reliable preclinical models for assessing drug-induced cardiotoxicity are essential to reduce the high rate of drug withdrawals during development. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have emerged as a promising platform for such assessments due to their expression of cardiacspecific ion channels and electrophysiological properties. In this study, we investigated the effects of eight arrhythmogenic drugs—E4031, nifedipine, mexiletine, JNJ303, flecainide, moxifloxacin, quinidine, and ranolazine—on hiPSC-CMs derived from both healthy individuals and a long QT syndrome (LQTS) patient using multielectrode array systems. The results demonstrated dose-dependent changes in field potential duration and arrhythmogenic risk, with LQTS-derived hiPSC-CMs showing increased sensitivity to hERG channel blockers such as E4031. Furthermore, the study highlights the potential of hiPSC-CMs to model disease-specific cardiac responses, providing insights into genetic predispositions and personalized drug responses.Despite challenges related to the immaturity of hiPSC-CMs, their ability to recapitulate human cardiac electrophysiology makes them a valuable tool for preclinical cardiotoxicity assessments. This study underscores the utility of integrating patientderived hiPSC-CMs with advanced analytical platforms, such as multi-electrode array systems, to evaluate drug-induced electrophysiological changes. These findings reinforce the role of hiPSC-CMs in drug development, facilitating safer and more efficient screening methods while supporting precision medicine applications.
3.Establishment of an In Vitro Embryo-Endometrium Model Using Alginate-Embedded Mouse Embryos and Human Embryoid Body
Yoon Young KIM ; Yong Jin KIM ; Jung Woo KIM ; Jiyeon KIM ; Sung Woo KIM ; Seung-Yup KU
Tissue Engineering and Regenerative Medicine 2025;22(1):77-89
BACKGROUND:
Embryo-endometrium cross-talk is one of the critical processes for implantation, and unsuccessful cross-talk leads to infertility. We established an endometrium-embryo (or embryoid bodies, hEBs) in vitro model in 2D and 3D conditions and assessed its potential through the fusion of embryos and the expression of specific markers.
METHODS:
C57BL/6 mouse embryos and human embryoid body (hEB) derived from embryonic stem cells were prepared as embryo models. Mouse endometrium (EM) and human endometrium cell line, HEC-1-A, were prepared, and 2D or 3D EMs were generated. The viability of the 3D endometrium was analyzed, and the optimal ratio of the gelation was revealed. The invasion of the embryos or hEBs was examined by immunostaining and 3D image rendering.
RESULTS:
The embryos and the alternative hEBs were effectively fused into 2D or 3D vitro EM models in both mouse and human models. The fused embryos and hEBs exhibited migration and further development. Notably, the established in vitro model expressed Oct4 and E-Cadherin, markers for early embryonic development; human CG Receptor and Progesterone Receptor, critical for implantation and pregnancy maintenance; and TSH Receptor, Epiregulin, and Prolactin, indicators of endometrial receptivity and embryo implantation.
CONCLUSION
This study marks a significant advancement in the field, as we have successfully established a novel in vitro model for studying embryo-endometrium cross-talk. This model, a crucial tool for understanding fertility and the causes of miscarriage due to failed implantation, provides a unique platform for investigating the complex processes of successful implantation and pregnancy, underscoring its potential impact on reproductive health.
4.Clinical Profiles of Multidrug-Resistant and Rifampicin-Monoresistant Tuberculosis in Korea, 2018–2021: A Nationwide Cross-Sectional Study
Jinsoo MIN ; Yousang KO ; Hyung Woo KIM ; Hyeon-Kyoung KOO ; Jee Youn OH ; Doosoo JEON ; Taehoon LEE ; Young-Chul KIM ; Sung Chul LIM ; Sung Soon LEE ; Jae Seuk PARK ; Ju Sang KIM
Tuberculosis and Respiratory Diseases 2025;88(1):159-169
Background:
This study aimed to identify the clinical characteristics of multidrug-resistant/ rifampicin-resistant tuberculosis (MDR/RR-TB) in the Republic of Korea.
Methods:
Data of notified people with tuberculosis between July 2018 and December 2021 were retrieved from the Korea Tuberculosis Cohort database. MDR/RR-TB was further categorized according to isoniazid susceptibility as follows: multidrug-resistant tuberculosis (MDR-TB), rifampicin-monoresistant tuberculosis (RMR-TB), and RR-TB if susceptibility to isoniazid was unknown. Multivariable logistic regression analysis was conducted to identify the factors associated with MDR/RR-TB.
Results:
Between 2018 and 2021, the proportion of MDR/RR-TB cases among all TB cases and TB cases with known drug susceptibility test results was 2.1% (502/24,447). The proportions of MDR/RR-TB and MDR-TB cases among TB cases with known drug susceptibility test results were 3.3% (502/15,071) and 1.9% (292/15,071), respectively. Among all cases of rifampicin resistance, 31.7% (159/502) were RMR-TB and 10.2% (51/502) were RR-TB. Multivariable logistic regression analyses revealed that younger age, foreigners, and prior tuberculosis history were significantly associated with MDR/ RR-TB.
Conclusion
Rapid identification of rifampicin resistance targeting the high-risk populations, such as younger generations, foreign-born individuals, and previously treated patients are necessary for patient-centered care.
5.Novel non-invasive and quantitative assessment of the renal function of transplanted kidneys using Doppler ultrasonography with the vascular index of superb microvascular imaging
Sung Hwan BAE ; Eun Ji LEE ; Jiyoung HWANG ; Seong Sook HONG ; Yun-Woo CHANG ; Boda NAM
Ultrasonography 2025;44(2):160-169
Purpose:
This study assessed the reproducibility and clinical value of the vascular index (VI), derived from superb microvascular imaging (SMI) using Doppler ultrasonography, for evaluating renal function in transplanted kidneys.
Methods:
This retrospective study included 63 renal transplant patients who underwent grayscale and Doppler ultrasonography with SMI from January 2022 to February 2023. The VI of the transplanted kidneys was measured using three methods (VIbox, VIF1, VIF2). The VI was compared across chronic kidney disease (CKD) groups categorized by estimated glomerular filtration rate (eGFR) and Kidney Disease: Improving Global Outcomes (KDIGO) CKD risk groups based on eGFR and albuminuria. The correlation between VI and renal function was evaluated. Univariate and multivariate linear regression analyses were used to identify predictors of eGFR.
Results:
Significant differences in VI were observed among CKD groups based on eGFR (VIbox, P=0.001; VIF1, P<0.001; VIF2, P<0.001) and KDIGO CKD groups based on eGFR and albuminuria (VIbox, P=0.039; VIF1, P=0.001; VIF2, P<0.001). VIF1 and VIF2 demonstrated moderate/high correlations with eGFR (r=0.627, P<0.001 and r=0.657, P<0.001, respectively) and serum creatinine (r=-0.626, P<0.001 and r=-0.649, P<0.001, respectively). VIbox moderately correlated with eGFR (r=0.445, P<0.001). Multivariate regression identified the urine albumincreatinine ratio (ACR) (adjusted odds ratio [aOR], 1.122; 95% confidence interval [CI], -0.007 to, 0.000; P=0.030) and VIF2 (aOR, 1.114; 95% CI, 0.466 to 1.235; P<0.001) were independently associated with eGFR.
Conclusion
The VI measured by drawing a region of interest along the border of the transplanted kidney in SMI (VIF2) is highly reproducible and correlates well with eGFR. Both VIF2 and ACR independently predict eGFR.
6.Pericapsular Nerve Group Block with Periarticular Injection for Pain Management after Total Hip Arthroplasty: A Randomized Controlled Trial
Hun Sik CHO ; Bo Ra LEE ; Hyuck Min KWON ; Jun Young PARK ; Hyeong Won HAM ; Woo-Suk LEE ; Kwan Kyu PARK ; Tae Sung LEE ; Yong Seon CHOI
Yonsei Medical Journal 2025;66(4):233-239
Purpose:
The purpose of this study was to compare the effectiveness of pericapsular nerve group (PENG) block with periarticular multimodal drug injection (PMDI) on postoperative pain management and surgical outcomes in patients who underwent total hip arthroplasty (THA). We hypothesized that PENG block with PMDI would exhibit superior effects on postoperative pain control after THA compared to PMDI alone.
Materials and Methods:
From April 2022 to February 2023, 58 patients who underwent THA were randomly assigned into two groups: PENG block with PMDI group (n=29) and PMDI-only group (n=29). Primary outcomes were postoperative numeric rating scale (NRS) at rest and during activity at 6, 24, and 48 hours postoperatively. Secondary outcomes were postoperative complications (nausea and vomiting), Richards-Campbell Sleep Questionnaire (RCSQ) score, length of hospital stay, Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index, Harris Hip Score (HHS), and total morphine usage after surgery.
Results:
There was no significant difference in postoperative pain for either resting NRS or active NRS. Postoperative nausea and vomiting, RCSQ score, length of hospital stay, WOMAC index, HHS, and total morphine usage exhibited no significant differences between the two groups.
Conclusion
Both groups showed no significant differences in postoperative pain and clinical outcomes, indicating that the addition of PENG block to PMDI does not improve pain management after applying the posterolateral approach of THA. PMDI alone during THA would be an efficient, fast, and safe method for managing postoperative pain. This article was registered with ClinicalTrials.gov (Gov ID: NCT05320913).
7.Multiple Allergen Simultaneous Test for Food Allergens Cannot Screen Wheat-Dependent, Exercise-Induced Anaphylaxis and α-Gal Syndrome
Jin-Sung PARK ; Youngsang YOO ; Jae-Woo KWON
Yonsei Medical Journal 2025;66(1):58-62
Screening tests for specific immunoglobulin E (sIgE) to food allergens, such as the multiple allergen simultaneous test (MAST), are widely used in patients with suspected food allergies in South Korea. We evaluated whether MAST could effectively screen wheatdependent exercise-induced anaphylaxis (WDEIA) and α-gal syndrome (AGS). We retrospectively reviewed patients with WDEIA and AGS diagnosed with unequivocal history and positive sIgE results for omega-5 gliadin and α-gal using ImmunoCAP, respectively. The clinical manifestations and results of MAST and ImmunoCAP (sIgE to wheat for WDEIA and beef/pork for AGS) were reviewed. In the MAST and ImmunoCAP results, class 0 (<0.35 units in each test) was considered negative. Medical records of 45 patients with WDEIA and 39 patients with AGS were reviewed. For WDEIA, 37 (82.2%) of patients had a history of anaphylaxis.Among those positive for omega-5 gliadin sIgE, 39 (87.7%) and 25 (55.6%) tested positive for gluten- and wheat-sIgE using ImmunoCAP, respectively. MAST performed on 15 patients yielded positive results for wheat-sIgE in 5 (33.3%). For AGS, 23 (59.0%) of patients had a history of anaphylaxis. Among those positive for α-gal sIgE, 32 (85.7%) and 37 (96.4%) tested positive for pork- and beefsIgE using ImmunoCAP, respectively, whereas MAST could not detect sIgE for pork and beef (0%, 0/17). MAST for sIgE to food allergens cannot screen WDEIA and AGS. The tests for sIgE to a specific component of food allergen, such as omega-5 gliadin for WDEIA and α-gal for AGS, should be used to screen WDEIA and AGS.
8.Predisposing Risk Factors Affecting Reversibility of Left Ventricular Diastolic Filling Pattern in Patients with Preserved Ejection Fraction
Dong-Gil KIM ; Sungsoo CHO ; Seongjin PARK ; Gi Rim KIM ; Kyu-Yong KO ; Sung Eun KIM ; Ji-won HWANG ; Joon-Hyung DOH ; Sung Uk KWON ; Jae-Jin KWAK ; June NAMGUNG ; Sung Woo CHO
Yonsei Medical Journal 2025;66(1):1-8
Purpose:
Improvement of left ventricular (LV) diastolic dysfunction (DD) is known to be a good prognostic factor in patients with heart failure with reduced ejection fraction (EF). In the present study, we investigated the predisposing risk factors affecting the reversibility of LV diastolic filling pattern (DFP) in patients with preserved EF.
Materials and Methods:
A total of 600 patients with pseudonormal LVDFP and preserved EF who underwent follow-up echocardiography were enrolled between 2011 and 2020. We compared their index and follow-up echocardiography findings and determined the predisposing risk factor affecting the reversibility of LVDFP.
Results:
Comparing the index and follow-up echocardiography findings showed that 379 (63%) patients had improved to normal or impaired relaxation LVDFP (improved group) and 221 (37%) patients had maintained or worsened LVDFP (unimproved group).The incidence of paroxysmal atrial fibrillation (PAF) was significantly higher in the unimproved group than in the improved group (4.7% vs. 9.5%, p=0.026). After adjustment for relevant clinical risk factors of diastolic dysfunction, PAF was determined to be an independent predisposing risk factor for the unimproved LVDFP (odds ratio: 2.10, 95% confidence interval: 1.06–4.15, p=0.033).Among the parameters of diastolic dysfunction in follow-up echocardiography, the left atrial volume index, mean E/A ratio, and E/e' were significantly improved in patients without PAF but remained in patients with PAF.
Conclusion
We identified that PAF was an independent predisposing risk factor of the unimproved LVDFP in patients with pseudonormal LVDFP and preserved EF. Therefore, early detection and management of PAF might be required in patients with LVDD and preserved EF to prevent adverse cardiovascular events.
9.A Pilot Study Examining If the Additional Use of a Continuous Glucose Monitoring Is Helpful for Glucose Control in Older Adults
Kwang Joon KIM ; Yang Sun PARK ; Eunseo SUN ; Euna JO ; Jiwon SHINN ; Hyeon Woo YIM ; Chang Oh KIM ; Hun-Sung KIM
Yonsei Medical Journal 2025;66(6):346-353
Purpose:
To investigate whether using a continuous glucose monitoring (CGM) for the second time (2nd_CGM) would be effective after using it for the first time (1st_CGM), depending on age.
Materials and Methods:
This study included patients aged ≥40 years who were diagnosed with type 2 diabetes and had used a CGM at least twice between 2017 and 2021. Participants were divided into two groups based on their age: those aged <60 years and those aged ≥60 years. We assessed the glycemic control status of the 1st_CGM and 2nd_CGM, along with the glycemic variability.
Results:
Overall, 15 patients were included in the study. The mean glucose level in users aged <60 years significantly decreased (p<0.001) owing to the CGM use, while it did not increase in those aged ≥60 years. In users aged ≥60 years, the 1st_CGM group showed a significant decrease in blood glucose levels over time (p<0.05), whereas the 2nd_CGM group only showed a non-significant decreasing trend. The time in range tended to increase in those aged <60 years but decreased in those aged ≥60 years. In those aged <60 years, the mean amplitude of glycemic excursions (p<0.001), standard deviation (p<0.05), and coefficient of variation (p<0.001) significantly decreased. In those aged ≥60 years, these parameters exhibited a non-significant decreasing trend.
Conclusion
Glycemic effect and variability improved as expected with 1st_CGM use. However, 2nd_CGM did not significantly improve glycemic effect or variability in users aged ≥60 years, contrary to expectations. To address this issue, further investigation is needed to understand why, compared to 1st_CGM, 2nd_CGM fails to achieve better glycemic control in individuals aged ≥60 years.
10.Single port–assisted diverting ileostomy formation for anastomotic leakage after low anterior resection
Kyong-Min KANG ; Heung-Kwon OH ; Hong-min AHN ; Hye-Rim SHIN ; Min-Hyeong JO ; Mi-Jeong CHOI ; Duck-Woo KIM ; Sung-Bum KANG
Journal of Minimally Invasive Surgery 2025;28(1):47-49
Stoma formation for fecal diversion is a common procedure in patients with various complicated conditions after colorectal surgery, such as anastomotic leakage. The singleincision laparoscopic approach for stoma creation offers several advantages, including a reduction in surgical wounds and related complications as well as optimal visualization of the surgical field. This video demonstrates a single-port–assisted diverting ileostomy in a 61-yearold man with anastomotic leakage following low anterior resection for advanced rectal cancer.

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