1.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.
2.Comparative Analysis of Vehicles for the Regeneration of Mouse Endometrial Damage Model
Ji Yeon HAN ; Yoon Young KIM ; Bo Bin CHOI ; Sung Woo KIM ; Seung-Yup KU
Tissue Engineering and Regenerative Medicine 2026;23(1):175-184
BACKGROUND:
Endometrial damage is a critical factor contributing to infertility, particularly in women with refractory thin endometrium or intrauterine adhesions. Therefore, developing innovative therapeutic strategies for endometrial regeneration is essential. This study evaluates the regenerative potential of endometrial stromal cell (EMSC) injection and EMSC-loaded patch application in a mouse model with ethanol-induced endometrial damage.
METHODS:
A mouse model of endometrial damage was established using ethanol injection into the uterine horn. EMSCs were isolated, cultured, and either HA-injected into the damaged endometrium or transplanted via a small intestinal submucosa (SIS)-based EMSC patch. Histological analyses were performed to assess endometrial thickness, gland regeneration, and fibrosis reduction.
RESULTS:
Both EMSC injection and SIS-based EMSC patch engraftment promoted endometrial regeneration. However, the SIS-based EMSC patch group exhibited significant improvements in endometrial thickness, gland formation, and fibrosis reduction compared to the EMSC injection group.
CONCLUSIONS
This study demonstrates the superior regenerative potential of an SIS-based EMSC patch over direct EMSC injection for endometrial repair. The findings suggest that scaffold-assisted cell therapy could be a promising approach for treating endometrial damage-related infertility. Further studies are required to optimize this strategy for clinical applications.
3.Predictors and patterns of early liver regeneration after major hepatectomy
Seoyeong KU ; Garam LEE ; Hyung Hwan MOON ; Hyungjune KU ; Won Jong YANG ; Junho SONG ; Suyeon KIM ; Chol Min KANG ; Amy CHOI ; Dong Hyeon GIM ; Young Il CHOI ; Dong Hoon SHIN ; Namkee OH ; Jinsoo RHU
Kosin Medical Journal 2026;41(1):58-66
Background:
Postoperative liver regeneration is essential for maintaining hepatic function. This study evaluated the rate, determinants, and volumetric patterns of early liver regeneration after hemihepatectomy.
Methods:
A retrospective review was conducted of 50 patients who underwent right or left hemihepatectomy between April 2019 and March 2025. Liver and spleen volumes (SV) were assessed preoperatively, at postoperative day (POD) 1 week, and at POD 3 months. Early liver regeneration rate (LRR) was defined as the percentage increase in remnant liver volume at POD 1 week relative to the preoperative future liver remnant (FLR), and patients were categorized into low (<50%) and high (≥50%) LRR groups. Clinical, biochemical, and volumetric variables were compared, and predictors of regeneration were identified using multivariable analyses. Regeneration patterns were also examined according to whether the FLR/standard liver volume (SLV) ratio was <50% or ≥50%.
Results:
FLR/SLV was the strongest independent predictor of rapid early liver regeneration (p<0.001). Remnants with FLR/SLV <50% exhibited rapid and sustained regeneration, whereas those with FLR/SLV ≥50% showed slower regrowth that plateaued after reaching approximately 90% of SLV. SV increased at POD 1 week in all patients; however, only the FLR/SLV ≥50% group showed a reduction by POD 3 months, whereas the <50% group maintained elevated volumes.
Conclusions
FLR/SLV reliably predicts early postoperative liver regeneration. Smaller remnants regenerate more rapidly, whereas persistent splenic enlargement suggests a sustained portal hemodynamic burden. Combined evaluation of FLR/SLV and SV may enhance perioperative risk assessment and surgical planning.
4.Prolotherapy for temporomandibular joint disorders:an updated comprehensive review
Yesel KIM ; Min-Joong KIM ; Pil-Young YUN ; Jeong-Kui KU
Journal of the Korean Association of Oral and Maxillofacial Surgeons 2025;51(6):354-361
Temporomandibular joint disorders (TMDs) comprise multifactorial conditions involving pain, joint noises, and restricted mandibular motion. Prolotherapy, involving intra-articular or periarticular injection of proliferative agents such as hypertonic dextrose or polydeoxyribonucleotide (PDRN), has recently gained attention as a regenerative therapy for refractory TMDs. This review summarizes current evidence and biological mechanisms underlying prolotherapy in temporomandibular joint (TMJ) disorders. Literature searches identified clinical and experimental studies evaluating efficacy, safety, and treatment protocols. Prolotherapy promotes fibroblast activation, collagen synthesis, and ligamentous stabilization. Dextrose remains the most validated proliferant, while PDRN provides comparable efficacy with less discomfort and shorter treatment intervals. Clinical data consistently show reduced pain and improved maximum mouth opening across chronic and degenerative TMJ cases, with preliminary imaging evidence of subchondral bone remodeling. Reported adverse events are minimal and transient. Prolotherapy appears to be a regenerative approach that may be regarded as one of the conservative treatment modalities for TMDs. Further controlled studies are needed to validate its long-term clinical and structural outcomes.
5.Residue depletion study and withdrawal period in milk for intramuscular gentamicin in dairy cows using LC-MS/MS
DoHui KIM ; Su Min NAM ; Hyoungjoon MOON ; Mi-Young PARK ; Hyun-Ok KU ; Hee YI ; Hwan Goo KANG
Journal of Veterinary Science 2025;26(6):e89-
Objective:
This study aimed to develop and validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify gentamicin residues in milk and to establish a withdrawal period for an intramuscular gentamicin product in dairy cows.
Methods:
Nine Holstein cows received a gentamicin product (50 mg gentamicin sulfate/ mL) at 0.1 mL/kg twice daily at 12 h intervals via intramuscular injection. Milk samples were collected before dosing and at 12 h intervals up to 168 h after the final administration and analysed with a validated LC-MS/MS method using heptafluorobutyric acid as an ion-pairing reagent.
Results:
The method showed recovery rates of 86%–104%, coefficients of variation of 3%–11%, and limits of detection and quantitation of 23 and 70 ng/mL, respectively. Mean gentamicin concentrations exceeded the maximum residue limit (MRL; 0.2 mg/kg) at 12 h during treatment and 12 h after the final administration, and were < MRL in all cows from 36 h after the last dose. Based on residue depletion data and a national non-statistical guideline, a withdrawal period of 40–48 h was derived, and the regulatory withdrawal period for this product was established as 3 days.
Conclusions
and Relevance: The validated LC-MS/MS method enables rapid quantitation of gentamicin residues in bovine milk. A 3-day regulatory withdrawal period for this product supports milk safety, regulatory compliance, and practical use in dairy herds.
6.2025 Korean Thyroid Association Management Guidelines for Radioactive Iodine Therapy in Patients with Hyperthyroidism
Kyeong Jin KIM ; Eyun SONG ; Mijin KIM ; Hyemi KWON ; Eu Jeong KU ; Hyun Woo KWON ; Jee Hee YOON ; Eun Kyung LEE ; Won Woo LEE ; Young Joo PARK ; Dong-Jun LIM ; Sun Wook KIM ; Ho-Cheol KANG ; Jae Hoon CHUNG ; Tae Yong KIM ; Sin Gon KIM ; Dong Gyu NA ; Jee Soo KIM
International Journal of Thyroidology 2025;18(1):65-79
Hyperthyroidism is a clinical condition characterized by excessive production of thyroid hormones, leading to thyrotoxicosis, with Graves’ disease being the most common underlying etiology. The treatment options for hyperthyroidism include antithyroid drug (ATD) therapy, radioactive iodine (RAI) therapy, and thyroidectomy. To establish standardized clinical recommendations specific to RAI therapy focusing on the safety, efficacy, pre- and post-treatment protocols, and follow-up monitoring, the Korean Thyroid Association convened a Task Force dedicated to developing evidence-based guidelines. Six key clinical questions were identified through expert panel discussion. A systematic review of literature published between 2013 and 2022 was conducted using PubMed and Embase with “hyperthyroidism” and “Graves’ disease” as search terms. Additional studies published during manuscript development were also included. The guideline classifies the clinical indications for RAI therapy into three categories: cases in which RAI is strongly recommended, may be considered, or not recommended. A fixed dose of 10–15 mCi is recommended for RAI therapy. While a routine low-iodine diet is not required, patients should avoid iodine-rich foods for at least one week before treatment. ATD should be discontinued 3–7 days prior to RAI and may be resumed afterward in selected cases. Prophylactic glucocorticoids are advised for patients with mild active thyroid eye disease and may be considered in those with additional risk factors. Thyroid function should be monitored at 4–6 weeks post-treatment, then every 2–3 months until stabilization, and subsequently at 6–12 month intervals or as clinically indicated. This guideline reflects recent advances in RAI therapy for hyperthyroidism and emphasizes the importance of individualized treatment decisions based on clinical characteristics, comorbidities, and patient preferences in Korea.
7.Comparison of da Vinci SP and Xi surgical systems for robotic lateral transperitoneal adrenalectomy: a retrospective single-center observational study
Da Young YU ; Young Woo CHANG ; Dohoe KU ; Seung Yeon KO ; Hye Yoon LEE ; Gil Soo SON
Annals of Surgical Treatment and Research 2025;108(6):367-373
Purpose:
Robotic adrenalectomy was developed to address the limitations of laparoscopic adrenalectomy and enhance the visualization, dexterity, and control of surgeons performing this beneficial minimally invasive technique. This study compared the clinical and perioperative outcomes of lateral transperitoneal adrenalectomy using da Vinci SP and Xi robotic systems (Intuitive Surgical).
Methods:
We retrospectively analyzed 84 patients who underwent robotic adrenalectomies at a single institution between January 2019 and July 2024. Sixty-two and 22 patients were treated with da Vinci Xi and SP systems, respectively.
Results:
No significant differences in patient demographics, tumor size, or postoperative hospital stay between the 2 groups were observed. The SP system demonstrated significantly shorter operative times for right-sided adrenalectomy (81.0 ± 17.1 minutes vs. 113.3 ± 26.2 minutes, P < 0.001), whereas no significant differences were observed in overall operative time (104.9 ± 28.2 minutes for Xi vs. 93.5 ± 23.2 minutes for SP, P = 0.094) or left adrenalectomy (99.9 ± 28.4 minutes for Xi vs. 104.0 ± 23.0 minutes for SP, P = 0.253).
Conclusion
The da Vinci Xi and SP systems are both effective for robotic adrenalectomy, with the SP system showing particular advantages in right-sided procedures.
8.Reducing Healing Period with DDM/rhBMP-2 Grafting for Early Loading in Dental Implant Surgery
Jeong-Kui KU ; Jung-Hoon LIM ; Jung-Ah LIM ; In-Woong UM ; Yu-Mi KIM ; Pil-Young YUN
Tissue Engineering and Regenerative Medicine 2025;22(2):261-271
Background:
Traditionally, dental implants require a healing period of 4 to 9 months for osseointegration, with longer recovery times considered when bone grafting is needed. This retrospective study evaluates the clinical efficacy of demineralized dentin matrix (DDM) combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) during dental implant placement to expedite the osseointegration period for early loading.
Methods:
Thirty patients (17 male, 13 female; mean age 55.0 ± 8.8 years) requiring bone grafts due to implant fixture exposure (more than four threads; ≥ 3.2 mm) were included, with a total of 96 implants placed. Implants were inserted using a two-stage protocol with DDM/rhBMP-2 grafts. Early loading was initiated at two months postoperatively in the mandible and three months in the maxilla. Clinical outcomes evaluated included primary and secondary stability (implant stability quotient values), healing period, bone width, and marginal bone level assessed via cone-beam computed tomography.
Results:
All implants successfully supported final prosthetics with a torque of 50Ncm, without any osseointegration failures. The average healing period was 69.6 days in the mandible and 90.5 days in the maxilla, with significantly higher secondary stability in the mandible (80.7 ± 6.7) compared to the maxilla (73.0 ± 9.2, p < 0.001). Histological analysis confirmed new bone formation and vascularization.
Conclusion
DDM/rhBMP-2 grafting appears to significantly reduce the healing period, enabling early loading with stable and favorable clinical outcomes.
9.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.
10.Reducing Healing Period with DDM/rhBMP-2 Grafting for Early Loading in Dental Implant Surgery
Jeong-Kui KU ; Jung-Hoon LIM ; Jung-Ah LIM ; In-Woong UM ; Yu-Mi KIM ; Pil-Young YUN
Tissue Engineering and Regenerative Medicine 2025;22(2):261-271
Background:
Traditionally, dental implants require a healing period of 4 to 9 months for osseointegration, with longer recovery times considered when bone grafting is needed. This retrospective study evaluates the clinical efficacy of demineralized dentin matrix (DDM) combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) during dental implant placement to expedite the osseointegration period for early loading.
Methods:
Thirty patients (17 male, 13 female; mean age 55.0 ± 8.8 years) requiring bone grafts due to implant fixture exposure (more than four threads; ≥ 3.2 mm) were included, with a total of 96 implants placed. Implants were inserted using a two-stage protocol with DDM/rhBMP-2 grafts. Early loading was initiated at two months postoperatively in the mandible and three months in the maxilla. Clinical outcomes evaluated included primary and secondary stability (implant stability quotient values), healing period, bone width, and marginal bone level assessed via cone-beam computed tomography.
Results:
All implants successfully supported final prosthetics with a torque of 50Ncm, without any osseointegration failures. The average healing period was 69.6 days in the mandible and 90.5 days in the maxilla, with significantly higher secondary stability in the mandible (80.7 ± 6.7) compared to the maxilla (73.0 ± 9.2, p < 0.001). Histological analysis confirmed new bone formation and vascularization.
Conclusion
DDM/rhBMP-2 grafting appears to significantly reduce the healing period, enabling early loading with stable and favorable clinical outcomes.

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