1.Aneuploidy rates and clinical outcomes in vitrified-warmed blastocyst transfer cycles: comparison of biopsy at fresh blastocyst versus vitrified-warmed blastocyst
Jun Woo KIM ; Sooyoung JEONG ; Jinkyung KO ; Jiyoung ANN ; Chang Young HUR ; Jin Ho LIM
Clinical and Experimental Reproductive Medicine 2026;53(2):121-127
Objective:
This study aimed to compare aneuploidy rates and clinical outcomes between trophectoderm biopsy at fresh blastocyst (biopsy-fresh) followed by vitrification and biopsy at vitrified-warmed blastocyst (biopsy-vitri) followed by next day transfer (without re-vitrification).
Methods:
This retrospective study included 844 patients undergoing 844 cycles conducted from August 2019 to December 2023. Preimplantation genetic testing for aneuploidy (PGT-A) was performed via trophectoderm biopsy using array comparative genomic hybridization or next-generation sequencing for comprehensive 24-chromosome screening. Patients were divided into two groups based on the blastocyst status at the time of biopsy: the biopsy-fresh group (531 patients) and the biopsy-vitri group (313 patients).
Results:
The clinical pregnancy rate was significantly higher in the biopsy-fresh group compared to the biopsy-vitri group (58.7% vs. 45.6%; odds ratio [OR], 1.695; 95% confidence interval [CI], 1.215 to 2.364; p=0.002). Furthermore, the biopsy-fresh group showed higher implantation rates (45.6% vs. 32.1%; OR, 1.767; 95% CI, 1.274 to 2.451; p=0.002), ongoing pregnancy or live birth rates per cycle (48.0% vs. 35.8%; OR, 1.652; 95% CI, 1.177 to 2.319; p=0.004), and rates of good-quality blastocysts (57.1% vs. 32.1%, p<0.001) compared with the biopsy-vitri group. Miscarriage rates did not differ significantly between the groups (18.2% vs. 21.4%; OR, 0.818; 95% CI, 0.457 to 1.465; p=0.501).
Conclusion
Biopsy at fresh blastocyst demonstrated superior clinical outcomes compared with biopsy at vitrified-warmed blastocyst, likely due to better embryo quality. Both biopsy at fresh blastocyst and vitrified-warmed blastocyst remain viable options for PGT-A, with biopsy at vitrified-warmed blastocyst serving as a practical alternative. Embryo quality and euploid status continue to be critical considerations for embryo transfer selection.
2.Endoscopic predictors of iron deficiency in Helicobacter pylori gastritis: a Kyoto classification-based study
Hyun Tak LEE ; Ah Young LEE ; Hyesun HONG ; Jun-young SEO
Clinical Endoscopy 2026;59(1):79-88
Background/Aims:
Helicobacter pylori infection is reportedly associated with iron-deficiency anemia. However, little is known about the association between the endoscopic features of H. pylori in the Kyoto classification of gastritis and iron deficiency. Therefore, we analyzed the endoscopic features of H. pylori gastritis and studied the association between these endoscopic features and iron deficiency.
Methods:
We retrospectively analyzed patients diagnosed with H. pylori gastritis between May 2022 and June 2023 who also underwent laboratory tests, including anemia profiling. Iron deficiency was defined as a ferritin level below 55 ng/mL. Multivariate analysis was used to assess the association between endoscopic features and iron deficiency.
Results:
Of the included patients, 47 had iron deficiency. Female patients were significantly more common in the iron-deficient group (87.2% vs. 33.4%, p<0.001). Endoscopically, nodularity (46.8% vs. 23.4%, p=0.001) and hyperplastic polyps (17.0% vs. 3.7%, p=0.001) were more common in patients with iron deficiency. Multivariate analysis identified younger age, female sex, and larger hyperplastic polyps (≥5 mm) as independent risk factors for iron deficiency.
Conclusions
Younger age, female sex, and larger hyperplastic polyps (≥5 mm) are associated with iron deficiency in patients with H. pylori gastritis. These features may help identify patients at higher risk of iron deficiency.
3.AI-driven Medical Care: Evaluation of Large Language Models in Generating Personalized Stroke Education Materials
Surim YOON ; Woo-Keun SEO ; Kyungseo KIM ; Seongvin JU ; Hyun Kyung KIM ; Hyung Jun KIM ; Jong-Won CHUNG ; Oh Young BANG ; Gyeong-Moon KIM ; Eun Young LEE ; Youngrak CHOI ; Soyoung YOO
Healthcare Informatics Research 2026;32(2):179-189
Objectives:
Large language models (LLMs) demonstrate remarkable potential in healthcare communication. However, whether they can process complex, high-volume medical information, such as stroke-related content, remains insufficiently validated. This study aimed to evaluate the natural language processing capabilities of LLMs in handling such content and to develop an evaluation instrument.
Methods:
A survey compared educational materials generated by two LLMs (ChatGPT 4.0 and Claude 3) with neurologist-authored content on stroke. The materials were based on two clinical scenarios representing distinct stroke etiologies: cardioembolism and large-artery atherosclerosis. They were evaluated in terms of accuracy, legality, ethics, comprehensiveness, and information delivery. Scores for comprehensiveness and information delivery were compared according to participants’ agreement with the use of LLMs in healthcare.
Results:
ChatGPT received the highest scores across all domains, except for legality in Scenario 2. In Scenario 1, the ranking for accuracy and summarization of clinical information was, from highest to lowest, ChatGPT, Claude, and the neurologist (η2 = 0.140, p < 0.001; η2 = 0.175, p < 0.001). The same hierarchy was observed in Scenario 2 for accuracy (η2 = 0.077, p < 0.001) and summarization (η2 = 0.194, p < 0.001). Participants who agreed with the use of LLMs in healthcare assigned higher scores for the comprehensiveness (Scenario 1, p = 0.005; Scenario 2, p = 0.007) and information delivery (Scenario 1, p = 0.003; Scenario 2, p = 0.026) of ChatGPT-generated materials than participants who did not agree.
Conclusions
LLMs demonstrated adequate capability to convey complex content, such as stroke-related information, in an accessible and understandable manner for non-experts.
4.Optimal use and cycling strategies of Janus kinase inhibitors in ulcerative colitis: current evidence and clinical implications from the KASID Guidelines Task Force Team
Seung Min HONG ; Dong Hyun KIM ; June Hwa BAE ; Seung Yong SHIN ; Eun Mi SONG ; Ji Eun KIM ; Young Joo YANG ; Jiyoung YOON ; Sang-Bum KANG ; Eun Soo KIM ; Seong-Eun KIM ; Seong-Jung KIM ; Jun LEE ; Soo-Young NA ; Soo Jung PARK ; Sang Hyoung PARK ; Miyoung CHOI ; Myung Ha KIM ; Won MOON ; Sung-Ae JUNG ;
Intestinal Research 2026;24(1):27-37
Janus kinase (JAK) inhibitors are an important treatment option for ulcerative colitis, providing rapid onset of action, oral administration, and efficacy even after biologic failure. The 3 approved agents—tofacitinib, filgotinib, and upadacitinib—differ in JAK isoform selectivity, leading to clinically meaningful differences in efficacy and safety. Evidence from network meta-analyses, clinical trials, and real-world studies consistently shows that upadacitinib provides the highest efficacy for induction and maintenance of remission, whereas filgotinib demonstrates the most favorable safety profile. The strong efficacy of upadacitinib and tofacitinib is particularly relevant in patients with severe disease, including acute severe ulcerative colitis, and upadacitinib maintains high efficacy regardless of prior advanced therapy exposure. JAK inhibitors also benefit extraintestinal manifestations. Although risks such as herpes zoster, serious infection, thromboembolism, and major cardiovascular events differ among agents, long-term data suggest generally acceptable safety when used appropriately. Intraclass JAK-to-JAK cycling is feasible, with about half of patients achieving steroid-free clinical remission in retrospective cohorts. Based on mechanistic, clinical, and real-world evidence, filgotinib may be a first-line option for patients with lower disease activity or when safety is a priority, whereas upadacitinib or tofacitinib may be preferred in higher disease activity. Strategically selecting agents may improve durability and outcomes.
5.Artificial intelligence-based personalized oncological outcome prediction model for upper urinary tract urothelial carcinoma after radical nephroureterectomy: A development and multicenter validation
Hyun Young LEE ; Hwanik KIM ; Bumjin LIM ; Dalsan YOU ; Cheryn SONG ; In Gab JEONG ; Jun Hyuk HONG ; Bumsik HONG ; Hanjong AHN ; Seung-hwan JEONG ; Ja Hyeon KU ; Jungyo SUH
Investigative and Clinical Urology 2026;67(1):15-23
Purpose:
To develop and validate an artificial intelligence (AI)-based personalized outcome prediction model for upper-urinary tract urothelial carcinoma patients undergoing radical nephroureterectomy.
Materials and Methods:
Data from patients who underwent radical nephroureterectomy between 2010 and 2020 across three hospitals were retrospectively analyzed. A model was developed using one tertiary center’s data and externally validated with data from two other hospitals. An AI model using XGBoost as risk estimator and bootstrapped Weibull Accelerated Failure Time model for 10-year survival probability was employed. Hyperparameter tuning used Optuna method. Model efficacy was assessed using concordance index, average Brier score, D-calibration, and six-month interval time-dependent area under the curve (AUC).
Results:
Of 1,039 patients, 627 qualified after excluding 50 with neoadjuvant chemotherapy. Model development used 564 patients (507 training, 57 test) with 9:1 stratified random split, plus 63 for internal validation and 362 for external validation. Significant parameters included preoperative glomerular filtration rate (p<0.001), hydroureteronephrosis (p=0.013), pathological N stage (p<0.001), concurrent carcinoma in situ (p<0.001), disease progression (p<0.001), and survival rate (p<0.001). Disease-free survival (DFS) model’s concordance index: internal validation 0.789, external validations 0.734 and 0.771. Overall survival (OS) model’s concordance index: internal validation 0.819, external validations 0.780 and 0.771. Mean time-dependent AUC was 0.66–0.77 for DFS and 0.67–0.80 for OS during 10-year periods.
Conclusions
AI-based model effectively predicts disease-free and OS outcomes for upper-urinary tract urothelial carcinoma patients with post-radical nephroureterectomy, showcasing robust performance across multicenter settings.
6.Effect of Induced Hypertension Therapy According to the Mechanism of Single Subcortical Infarction
Seung Taek OH ; Jun Young CHANG ; Dong-Wha KANG ; Sun U. KWON ; Sang Hee HA ; Bum Joon KIM
Journal of Clinical Neurology 2026;22(2):153-159
Background:
and Purpose Induced hypertension therapy (IHT) is effective for treating early neurological deterioration (END) in patients with single subcortical infarction (SSI). However, the underlying pathophysiology of SSI is diverse and may affect the efficacy of IHT.
Methods:
We reviewed patients with SSI who experienced END and received IHT were enrolled. END was defined as ≥2-point increase in the National Institutes of Health Stroke Scale (NIHSS) score, ≥1 motor point increase. IHT was performed by using phenylephrine infusion to raise systolic blood pressure by 10%–20% over baseline. SSI was classified into three subtypes: distal (dSSI), proximal (pSSI), and SSI with parental artery disease (SSIPAD; with stenosis at parental artery disease <50%). Responders were defined as patients who showed neurological improvement (decrease of ≥2 points in NIHSS, ≥1 motor point decrease) within one day after IHT initiation. Multivariable analysis identified factors associated with responders.
Results:
Characteristics were compared between responders and non-responders, and factors associated with response to IHT were investigated. Among 96 patients (mean age, 64.7± 12.9 years; 61.5% male), 49 (51.0%) patients were categorized as responders. Multivariable analysis showed that pSSI (adjusted odds ratio [aOR]=18.10, 95% confidence interval [CI] 5.04–80.60, p<0.001) and SSIPAD (aOR=4.56, 95% CI 1.31–19.00, p=0.024) were associated with a positive response to IHT compared to dSSI. Additionally, less white matter changes (Fazekas scale 0–1) were associated with a better response to IHT (aOR=0.15, 95% CI 0.03–0.67,p=0.019).
Conclusions
Response to IHT varied according to SSI subtypes and the severity of small vessel changes.
7.Eyeball Donation and Management System
Jaeyoung KIM ; Chul Young CHOI ; Jae Yong KIM ; Roo Min JUN ; Eun Chul KIM ; Yong-Soo BYUN ; Jong Hwa JUN ; Dong Hyun KIM ; Yunjin LEE ; Hyung Keun LEE ; Mee Kum KIM
Journal of the Korean Ophthalmological Society 2026;67(2):33-46
Purpose:
To propose improvements for promoting eyeball donation and managing donated corneas, this study analyzed the current system in Korea and reviewed relevant Korean laws, international standards, and foreign practices.
Methods:
To understand the current situation in Korea, annual reports published by the Korean Network for Organ Sharing and existing Korean laws were examined. For the international context, references were made to the National Organ Transplant Act, 21 CFR Part 1271 (Code of Federal Regulations Title 21 Part 1271), Current Good Tissue Practice guidelines of the Food and Drug Administration, and the Medical Standards of the Eye Bank Association of America in the United States. Opinions on promoting eyeball donation, improving the monitoring system for donated corneas and revising laws related to cornea management were gathered. The perspectives of 31 experts affiliated with the Korea Cornea Society were collected through a survey.
Results:
Currently, there are no laws or regulations that can be appropriately applied to the cornea which has properties of both organs and tissue. Additionally, there is no law regulating imported corneas. Therefore, there is a need to legislate or revise the current law; all experts who conducted the survey agreed on this. Furthermore, the current system faces limitations in the efficient procurement, stable supply, and management of donor corneas, as well as in donation promotion. To address these issues, the establishment of independent legislation for managing donated corneas and a National Central Eye Bank was proposed. This central body would oversee continuous personnel training, education, and monitoring, along with ensuring stable procurement, processing, and supply of corneas within a structured management system. Sixty-eight percent of the surveyed experts agreed with this proposal.
Conclusions
To establish a safe and efficient Korean corneal supply and demand system, it is imperative to enact cornea-specific laws, including the establishment of a National Central Eye Bank.
8.Clinical Features and Prognostic Factors of Indirect Traumatic Optic Neuropathy
Jun HEO ; Jungyul PARK ; Hee-Young CHOI
Journal of the Korean Ophthalmological Society 2026;67(6):201-212
Purpose:
Our study identified prognostic factors affecting visual outcomes in patients with unilateral indirect traumatic optic neuropathy (TON), determined the risk of legal blindness, and assessed changes in visual acuity, visual fields, retinal structure, and the therapeutic effect of high-dose corticosteroid treatment.
Methods:
We retrospectively reviewed the medical records of 52 patients (52 eyes) diagnosed with TON between 2014 and 2023. Patients were categorized into two groups according to the final best-corrected visual acuity (BCVA): Group 1 (BCVA ≥0.1) and Group 2 (BCVA <0.1). Prognostic factors were analyzed using logistic regression, and receiver operating characteristic curve analysis was performed to determine optimal cutoff values. Longitudinal changes in visual acuity, visual field index (VFI), and retinal structural parameters were assessed using a generalized linear mixed model.
Results:
Factors significantly associated with Group 1 included the absence of intracranial hemorrhage, administration of high-dose steroids within 24 h, and better logMAR visual acuity and VFI within 4 weeks post-trauma. In multivariate analysis, VFI within 4 weeks remained significantly associated with favorable visual outcomes (p = 0.008). The optimal VFI cutoff value for predicting a good prognosis was 13%, yielding a sensitivity of 90% and specificity of 93.3%. Visual acuity outcomes over time differed significantly according to the timing of high-dose steroid administration.
Conclusions
VFI within 4 weeks after injury was the most reliable prognostic indicator, demonstrating high sensitivity and specificity for predicting legal blindness. Early administration of high-dose steroids within 24 h helped prevent visual deterioration. These findings emphasize the importance of early quantitative assessment of visual function and prompt therapeutic intervention to guide treatment strategies in patients with TON.
9.The Korean Rectal Cancer Multidisciplinary Committee Clinical Practice Guidelines for Rectal Cancer version 2.0
Hyo Seon RYU ; Hyun Jung KIM ; Dong Hyun KANG ; Yoo-Kang KWAK ; Han Deok KWAK ; Yoon-Hye KWON ; Dalyon KIM ; Baek-Hui KIM ; Jae Hyun KIM ; Ji Hun KIM ; Jin Won KIM ; Tae Hyung KIM ; Hae Young KIM ; Soo Min NAM ; Gyoung Tae NOH ; Jun Woo BONG ; Nak Song SUNG ; Seon Hui SHIN ; Kil-Yong LEE ; Sung Chul LEE ; Sea-Won LEE ; Jung Won LEE ; Jong Min LEE ; Myung Hoon IHN ; Joo Han LIM ; Woong Bae JI ; Dae Hee PYO ; Young Ki HONG ; Jung-Myun KWAK ;
Annals of Coloproctology 2026;42(1):4-33
Rectal cancer, which accounts for approximately 40% of colorectal cancers, remains a major clinical concern. Recent advances in diagnostic imaging, surgical techniques, radiotherapy, and systemic treatment have steadily improved rectal cancer outcomes. Considering this, the Korean Rectal Cancer Multidisciplinary (KRCM) Committee has aimed to provide clinicians and policymakers with up-to-date, evidence-based clinical practice guidelines to support optimal decision-making, reflecting current evidence, the Korean healthcare context, and patient values and preferences. The Clinical Practice Guidelines for Rectal Cancer version 2.0 were developed through multidisciplinary collaboration with related academic societies, building upon and updating the KRCM Clinical Practice Guidelines version 1.0 (titled “Multidisciplinary guidelines for the management of rectal cancer”). These consensus guidelines of the KRCM were established based on a comprehensive literature review, evidence synthesis, with recommendation development guided by the GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology, and consideration of applicability in real-world clinical practice under the national health insurance system. Each recommendation has been presented with its strength and level of evidence.
10.Molecular Epidemiology of Extended-spectrum β-Lactamase-producing Escherichia coli in South Korea: A Korean Global Antimicrobial Resistance Surveillance System Report
Dokyun KIM ; SungYoung LEE ; Jun Sung HONG ; Min Hyuk CHOI ; Hyun Soo KIM ; Young Ree KIM ; Young Ah KIM ; Young UH ; Kyeong Seob SHIN ; Jeong Hwan SHIN ; Jeong Su PARK ; Kyoung Un PARK ; Soo Hyun KIM ; Jong Hee SHIN ; Jungsik YU ; Seok Hoon JEONG
Annals of Laboratory Medicine 2026;46(1):72-82
Background:
Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is among the most important multidrug-resistant pathogens causing bloodstream infections (BSIs).Cefotaximase (CTX-M) enzymes are the most common and highly diverse ESBL family in E.coli. CTX-M-15 in group CTX-M-1 and CTX-M-14 in group CTX-M-9 are the most extensively disseminated enzymes. Multidrug-resistant E. coli strains complicate empirical therapy and increase healthcare burden globally and in Korea. We investigated the molecular epidemiology, sequence types (STs), and ESBL genotypes of E. coli bloodstream isolates in Korea and identified clinical risk factors for cefotaxime resistance.
Methods:
We collected all non-duplicated isolates of E. coli and related clinical information from patients with BSIs at eight sentinel hospitals in the Korean Global Antimicrobial Resistance Surveillance System (Kor-GLASS) collection network during 2017–2021. Duplicate isolates were removed to ensure representativeness of the data. Antimicrobial susceptibility was tested using disk diffusion tests, and multilocus sequence typing and betalactamase genotyping were performed.
Results:
Among 9,232 E. coli blood isolates, resistance rates to cefotaxime and ceftazidime were 36.4% and 11.4%, respectively. Among the clinical factors, age > 65 yrs (adjusted odds ratio [aOR], 1.36), hospital-origin infection (aOR, 2.55), and admission type (intensive care unit [ICU] vs. general ward; aOR, 1.34) were significant cefotaxime resistance risk factors. ST131 was the most prevalent among cefotaxime-resistant E. coli (64.8%, 2,180/3,363), followed by ST1193 (5.3%, N = 177), and ST69 (5.1%, N = 170).ST131, ST648, ST405, and ST410 cefotaxime-resistant E. coli isolates frequently harbored blaCTX-M-15, whereas ST1193 and ST68 showed a high proportion of blaCTX-M-27 carriers, and most ST457 and ST5150 isolates carried blaCTX-M-55.
Conclusions
Continuous monitoring of ESBL-producing E. coli is required to prevent further dissemination, guide empirical therapy, inform infection control policies, and ensure early detection of multidrug-resistant clones with the potential for widespread transmission.

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