1.Effects of the timing of testicular sperm retrieval on intracytoplasmic sperm injection outcomes
Tae Ho HWANG ; Jae Kyun PARK ; Dong Hyuk SHIN ; Won Hee LEE ; Ye Eun KIM ; Yohan HEO ; Tae Ho LEE ; Seung-Ryeol LEE ; Seung-Hun SONG
Clinical and Experimental Reproductive Medicine 2026;53(2):115-120
Objective:
This study aimed to evaluate reproductive outcomes according to the timing of testicular sperm retrieval.
Methods:
The study included 282 infertile couples divided into three groups: group A (freeze-thawed testicular sperm extraction [TESE] sperm, n=233), group B (fresh TESE sperm collected 1 day before ovum pickup, n=22), and group C (fresh TESE sperm collected on the same day as ovum pickup, n=27). The indications for TESE were surgically uncorrectable azoospermia or ejaculation failure, often accompanied by medical comorbidities such as diabetes mellitus and spinal cord injury. The outcome parameters assessed were fertilization rates, embryo quality, and clinical pregnancy rates.
Results:
The mean paternal age was 36.8±5.7 years, and the mean maternal age was 32.6±3.5 years. The mean duration of infertility was 2.9±1.8 years. The fertilization rates were 70.7%, 78.9%, and 73.0% for groups A, B, and C, respectively (p=0.047). The percentages of good-quality embryos were 68.2%, 65.3%, and 48.4%, respectively (p=0.007); specifically, the percentage of good-quality embryos was significantly lower in group C compared with the other two groups. Clinical pregnancy rates per transfer were similar at 51.1%, 50.0%, and 48.1% (p=0.958), with no differences observed in miscarriage rates.
Conclusion
Testicular sperm retrieval can be safely performed 1 day before ovum pickup, resulting in favorable fertility outcomes.
2.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.
3.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.
4.Surgical management of intrahepatic cholangiocarcinoma and combined hepatocellular-cholangiocarcinoma: a narrative review of principles, technical nuances, and emerging strategies
Woohyung LEE ; Kwang Pyo HONG ; Jae Hoon LEE ; Mirang LEE ; Minkyu SUNG ; Seung Jae LEE ; Ki Byung SONG ; Dae Wook HWANG ; Song Cheol KIM
Journal of Liver Cancer 2026;26(1):19-28
Intrahepatic cholangiocarcinoma (CCA) is the second most common primary liver cancer after hepatocellular carcinoma (HCC). However, combined HCC-CCA is a rare malignancy exhibiting hepatocytic and cholangiocytic differentiation. For both tumors, R0 resection with regional lymph node dissection remains the only potentially curative treatment. Nevertheless, key aspects of surgical management remain controversial. In this narrative review, we synthesize contemporary evidence on the surgical management of intrahepatic CCA and combined HCC-CCA. We summarize current data on lymphadenectomy, safety, and oncologic comparability of minimally invasive vs. open surgery, and integration of liver hypertrophy techniques for major hepatectomy. We also review the emerging clinical experience with immune checkpoint inhibitor-based chemoimmunotherapy as a neoadjuvant treatment and conversion surgery for advanced disease. We highlight persisting knowledge gaps and propose practical perspectives to support individualized surgical planning for this heterogeneous disease.
5.Bisphosphonates as a Tacrolimus-Sparing Strategy in Kidney Transplantation: Insights from a Retrospective Analysis
Hee Byung KOH ; Hyo Jeong KIM ; Ga Young HEO ; Namki HONG ; Yaeji LEE ; Seung Hwan SONG ; Hoon Young CHOI ; Chan-Young JUNG ; Hyung Woo KIM ; Jaeseok YANG ; Kyu Ha HUH ; Chung Mo NAM ; Beom Seok KIM
Yonsei Medical Journal 2026;67(1):17-26
Purpose:
Due to chronic toxicity, tacrolimus-sparing is an important issue in kidney transplant recipients (KTRs). Several studies have shown that bisphosphonate use is associated with favorable graft outcomes in KTRs. We investigated whether the association between tacrolimus trough levels (TTLs) and graft outcomes differed according to bisphosphonate use in KTRs.
Materials and Methods:
We conducted a retrospective study encompassing 1441 KTRs who were administered tacrolimus-based immunosuppressants. The primary exposure was a time-dependent cross-product of TTLs (low TTLs vs. normal-high TTLs with a reference of 6 ng/mL) and bisphosphonate use. Two primary outcomes were evaluated: overall graft loss (death or conversion to kidney replacement) and an estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m 2 .
Results:
During the median follow-up of 6.1 (3.4–9.7) years, overall graft loss occurred in 157 (10.9%) patients. Cox regression revealed that normal-high TTLs without bisphosphonate use were associated with a reduced risk of overall graft loss [adjusted hazard ratio (aHR), 0.65; 95% confidence interval (CI), 0.45–0.95] compared to low TTLs without bisphosphonate use. The use of bisphosphonate in conjunction with normal-high TTLs correlated with an even lower risk of overall graft loss (aHR, 0.25; 95% CI, 0.08–0.80) compared with low TTLs without bisphosphonate use. In patients with low TTLs, bisphosphonate use was associated with a reduced risk of overall graft loss compared with non-use (aHR, 0.20; 95% CI, 0.09–0.43). Similar trends were observed in the eGFR outcome.
Conclusion
The use of bisphosphonate was associated with favorable graft outcomes, even with low TTLs. Incorporating bisphosphonate into a conventional immunosuppressant regimen may potentially reduce tacrolimus requirement.
6.Korean Thyroid Association Guidelines on the Management of Differentiated Thyroid Cancers; Part II. Follow-up Surveillance after Initial Treatment 2026
Eun Kyung LEE ; Seung Heon KANG ; Bon Seok KOO ; Mijin KIM ; Min Joo KIM ; Bo Hyun KIM ; Ji Won KIM ; Dong Gyu NA ; Sohyun PARK ; Ji-In BANG ; Kyorim BACK ; Youngduk SEO ; Young-Ik SON ; Young Shin SONG ; Dong Yeob SHIN ; Jong-Hyuk AHN ; Hwa Young AHN ; So Won OH ; Ho-Ryun WON ; Won Sang YOO ; Min Kyoung LEE ; Sang-Woo LEE ; Jeongmin LEE ; Ji Ye LEE ; Dong-Jun LIM ; Ki-Wook CHUNG ; Ari CHONG ; Jin Hyang JUNG ; Sun Wook CHO ; Yoon Young CHO ; Chae Moon HONG ; Young Joo PARK ;
International Journal of Thyroidology 2026;19(1):1-40
In patients with differentiated thyroid cancer (DTC), initial recurrence risk stratification based on clinical, histopathological, and perioperative data remains the key determinant for guiding management strategies during the first 1-2 years post-treatment. However, the adoption of ongoing risk stratification (ORS), which dynamically reassesses risk by integrating longitudinal clinical data and treatment response, enables more precise long-term prognostic assessment and facilitates highly individualized management. Building upon recent guidelines, the 2026 KTA guideline has been further refined by incorporating robust evidence from large-scale national cohorts and comprehensive systematic reviews. These updated recommendations outline contemporary concepts of ORS, risk-adapted TSH suppression targets, optimized surveillance modalities for recurrence detection, and disease-specific long-term follow-up strategies. Reflecting the paradigm shift toward de-escalated treatment, this revision integrates evolved perspectives on TSH suppression intensity, the clinical interpretation of thyroglobulin levels, and tailored follow-up intervals. These evidence-based recommendations aim to minimize unnecessary treatment and excessive surveillance in the large proportion of patients with excellent prognosis after initial therapy, while ensuring that each patient receives appropriately tailored and effective long-term management.
7.Artificial Intelligence-Based Exosome Analysis for Improving Diagnostic Performance of Breast Lesions on Ultrasound: Protocol of a Prospective, Multicenter Cohort Study
Sung Eun SONG ; Hyunku SHIN ; Yong PARK ; Yeonho CHOI ; Seung Pil JUNG
Journal of Breast Cancer 2026;29(2):183-191
Purpose:
Exosome-surface enhanced Raman spectroscopy-artificial intelligence platform (exosome-SERS-AI) is an innovative liquid biopsy method that acquires SERS signals from plasma exosomes and analyzes them using deep learning models to diagnose cancer. This study aimed to evaluate whether exosome-SERS-AI could increase the diagnostic accuracy of ultrasonography (US) for suspicious breast lesions.
Methods
This prospective multicenter study enrolled 500 patients between November 2024 and December 2025. Eligible participants will be women aged ≥ 40 years who will undergo US performed by specialized breast radiologists and have suspicious breast lesions assigned to a Breast Imaging Reporting and Data System (BI-RADS) category 3–5 assessment. A 6 mL whole blood sample was collected from each participant. After plasma separation, SERS, which is highly sensitive to exosomes, was employed to measure Raman signals, and the acquired data were processed using artificial intelligence algorithms. Following sampling, all patients underwent US-guided core needle biopsy for breast lesions classified as BI-RADS category 4 and 5, and 12-months of follow-up US for lesions classified as BIRADS category 3. Histopathological examination was used as the reference standard for BIRADS 4 and 5 lesions, whereas stability on 12-month follow-up US was used as the reference standard for BI-RADS 3 lesions. The cohort is expected to have an equal distribution of benign and malignant cases. The following outcome measures were compared between US alone and the combination of exosome-SERS-AI with US: sensitivity, specificity, positive predictive value, negative predictive value, and the area under the receiver operating characteristic curve. Enrollment is expected to be completed by 2025, and the study results are expected to be presented in 2026.Discussion: This prospective multicenter study will evaluate the performance of exosome-SERSAI compared to US in women with BI-RADS categories 3–5. Participant enrollment is ongoing.
8.Parent artery encroachment after clipping of kissing middle cerebral artery bifurcation aneurysm: A case report
Changheon KIM ; HyoJun KIM ; Taesik SONG ; Seung Kon HUH
Journal of Cerebrovascular and Endovascular Neurosurgery 2026;28(1):77-82
Background:
Kissing middle cerebral artery bifurcation aneurysms (KMCBA) are rare vascular lesions. Their complex morphology and limited surgical experience may predispose patients to devastating complications.Cases: Among 100 patients who underwent microsurgical clipping for cerebral aneurysms between May 2022 and April 2025, two were diagnosed with unruptured KMCBA. In Case 1, the two aneurysm sacs of a left KMCBA were clipped separately using interlocking and fenestrated clips without premature rupture. In Case 2, both aneurysm sacs of a right KMCBA were clipped simultaneously with a long J-shaped clip. Postoperatively, the patient developed left hemiparesis due to clip-induced encroachment of the superior trunk of M2. Revision clipping with a shorter L-shaped clip restored flow, and the patient was discharged with a modified Rankin scale (mRS) score of 4.
Conclusions
Successful microsurgical clipping of KMCBA requires meticulous surgical strategies to avoid parent artery encroachment, including separate clipping of each aneurysm neck whenever feasible, appropriate clip selection, and the use of multimodal intraoperative anatomical and physiological monitoring.
9.Sequential Mediation by Maternal Weight Gain and Late Blood Metal Concentration in the Association Between Heavy Metal Exposure in Early Pregnancy and Fetal Growth
Seung-Ah CHOE ; Jue Seong LEE ; Changmin KANG ; Jungheum JO ; Wonsuck YOON ; Dae Jin SONG ; Young YOO ;
Journal of Korean Medical Science 2026;41(1):e16-
Background:
To assess the mediation effect of gestational weight gain (GWG) and blood heavy metal levels in the late pregnancy affecting the association between early pregnancy metal exposure and fetal growth.
Methods:
We analyzed data from Korean Children’s Environmental Health Study cohort comprising 4,712 full-term births. Blood levels of lead (Pb), mercury (Hg), and cadmium (Cd) during pregnancy, and newborn birthweights were retrieved. We applied single-exposure model to assess the association between heavy metal levels and newborn anthropometric measures and conducted path analyses to examine the direct and indirect effects of heavy metal levels in early pregnancy on newborn measures.
Results:
Exposure to Pb (β = −15.470, P = 0.036) and Cd (β = −24.150, P = 0.004) during late pregnancy were associated with lower birthweight. Early exposure to Pb was not directly associated with lower birthweight, however, mediation of late exposure to Pb (β = −7.417, P = 0.049) resulted in lower birthweight (β = −14.787, P = 0.036). Early exposure to Hg was associated with higher birthweight, however, indirect paths via GWG (β = 3.626, P = 0.048) and late Hg levels (β = −12.929, P = 0.111) countered each other, resulting in the nullification of the total effect (β = −8.519, P = 0.301).
Conclusion
The effect of Pb exposure in early pregnancy on birthweight was mediated by GWG and Pb exposures during late pregnancy. When assessing the impact of heavy metal exposure on birthweight, it is important to note that GWG and late heavy metal levels act as mediators, rather than confounders.

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