1.Transformation of Pleomorphic Xanthoastrocytoma with Germline ATM Mutation into a SMARCB1-Deficient Rhabdoid Tumor: A Case Report
Hyeonseung LEE ; Hyun Jin PARK ; Bo Kyung KIM ; Kyung Taek HONG ; Hyoung Jin KANG ; Sung-Hye PARK ; Ji Hoon PHI ; June-Young KOH ; Jung Yoon CHOI
Clinical Pediatric Hematology-Oncology 2026;33(1):34-38
Secondary rhabdoid tumors (RTs) with atypical teratoid/rhabdoid tumor-like features rarely arise from, or coexist with, pleomorphic xanthoastrocytomas (PXAs), and their clinicopathological and molecular characteristics remain poorly understood. We report a 17-year-old girl with a temporal lobe mass that, upon gross total resection, pathologically contained both RT and PXA components. Immunohistochemistry revealed loss of INI1 expression restricted to the RT component, while the PXA area retained INI1. Next-generation sequencing identified a shared BRAF::TRIM24 fusion and homozygous deletion of CDKN2A/2B in both components, indicating a shared clonal origin. Additionally, a germline ATM frameshift mutation (c.5288_5289insGA) was identified in both tumor components, making the first such report in central nervous system tumors. SMARCB1 loss was confined to the RT component, further supporting the hypotheses of clonal evolution and secondary transformation. Despite gross total resection, craniospinal irradiation, and chemotherapy, the patient developed rapid leptomeningeal dissemination and died 5 months after surgery. This case provides clinicopathological and molecular evidence for clonal evolution and secondary transformation of PXA into an RT. The presence of germline ATM mutation may have therapeutic and biological relevance. Further studies are required to clarify the pathogenesis and optimal management of these rare and aggressive tumors.
2.Sequential Changes in Range of Motion and Capsular Fibrosis Following Remobilization in a Rat Adhesive Capsulitis Model Using Cast Immobilization
Du-Han KIM ; Ji-An KIM ; Jong Pil YOON ; Chul-Hyun CHO
Clinics in Orthopedic Surgery 2026;18(1):107-115
Background:
The objective of this study was to investigate sequential changes in range of motion (ROM) and histopathology of the joint capsule after remobilization in a rat adhesive capsulitis (AC) model using cast immobilization.
Methods:
Thirty-five 6-week-old Sprague-Dawley rats were immobilized with casting of the left shoulder. After 4 weeks, the rats were randomly divided into 7 groups (n = 5 per group) according to the duration of remobilization following cast removal: 0 (D0), 1 (W1), 2 (W2), 3 (W3), 4 (W4), 5 (W5), and 6 (W6) weeks. At each time point, 5 rats were euthanized for measurement of the glenohumeral abduction angle and evaluation of capsular thickness in the axillary recess.
Results:
Abduction angle was sequentially increased at each time point after remobilization with cast removal. Significant differences between immobilized and non-immobilized shoulders were observed at D0 (130.4° vs 161.3°), W1 (144.7° vs 160.7°), and W2 (142.3° vs 161.3°). Significant differences in capsular thickness of the axillary recess were observed between immobilized and non-immobilized shoulders at all time periods including D0 (98.0 μm vs. 12.9 μm), W1 (117.7 μm vs. 12.2 μm), W2 (115.7 μm vs.13.1 μm), W3 (54.1 μm vs. 14.9 μm), W4 (54.5 μm vs. 13.4 μm), W5 (23.8 μm vs. 13.5 μm), and W6 (19.8 μm vs. 12.4 μm). Significant differences in capsular fibrosis scores were observed between immobilized and non-immobilized shoulders at W1 (2.2 vs. 0.2) and W2 (2.2 vs. 0.0).
Conclusions
Our study showed that ROM increased sequentially after remobilization in a rat AC model using cast immobilization, and it was normalized at 6 weeks after cast removal. Capsular thickening decreased sequentially, but remained at 6 weeks after cast removal. These findings may provide useful information for further research into verifying potential therapeutic targets using a rat AC model with cast immobilization.
3.Health Effects of Sugar-Sweetened and Artificially Sweetened Beverages: Umbrella Review and Evidence-Based Consensus Statement of the Korean Diabetes Association and the Korean Nutrition Society
Jong Han CHOI ; SuJin SONG ; Soo Kyoung KIM ; Jae Won CHO ; Jae Hyun BAE ; Shinje MOON ; Jeong Hyun LIM ; YeonHee LEE ; Ji-Yun HWANG ; YoonJu SONG ; Sang Soo KIM
Diabetes & Metabolism Journal 2026;50(1):32-46
Background:
Excess intake of added sugars contributes to obesity, type 2 diabetes mellitus (T2DM), cardiovascular disease (CVD), and premature mortality. Sugar-sweetened beverages (SSBs), the main source of added sugars, are consistently linked to adverse outcomes. Artificially sweetened beverages (ASBs) have been suggested as short-term substitutes, but evidence regarding benefits and harms remains inconclusive, and guidance is lacking.
Methods:
This consensus statement draws on a structured evidence review combining two approaches: an updated meta-analysis of randomized controlled trials (RCTs) assessing short- to intermediate-term effects of replacing SSBs with ASBs on weight and metabolic outcomes; and an umbrella review of systematic reviews of cohort studies evaluating long-term associations of SSBs and ASBs with major outcomes, including mortality, CVD, and T2DM.
Results:
In 14 RCTs (3–76 weeks), replacing SSBs with ASBs produced modest reductions in body weight (–0.73 kg) and body fat (–0.72%), with inconsistent effects on glycemic and cardiometabolic markers. Evidence from 20 systematic reviews of cohorts (up to 34 years follow-up) showed that higher intake of both SSBs and ASBs was associated with increased risks of T2DM, CVD, and mortality, with relative risks for ASBs similar to those for SSBs.
Conclusion
ASBs may serve as a short-term substitution for individuals with high SSB intake, particularly those at elevated metabolic risk. However, regular or long-term use is not recommended due to uncertain safety and potential reinforcement of sweet preference. Public health strategies should emphasize reducing both SSBs and ASBs, prioritizing water and unsweetened beverages as the ultimate goal.
4.Risk Assessment for Carotid Atherosclerosis in Asymptomatic Patients with Metabolic Dysfunction-Associated Steatotic Liver Disease
Hana PARK ; Ji Young LEE ; Sungwon PARK ; Hyo Jeong LEE ; Suh Eun BAE ; Jaeil KIM ; Hye-Sook CHANG ; Jaewon CHOE ; Hye Won PARK ; Ju Hyun SHIM
Gut and Liver 2026;20(1):125-136
Background/Aims:
Cardiovascular disease remains a major cause of mortality in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). This study evaluated the association between subclinical carotid atherosclerosis (SCA) and MASLD or MASLD and increased alcohol intake (MetALD) in asymptomatic individuals.
Methods:
This cross-sectional study included 56,889 adults undergoing health check-ups in South Korea. Hepatic steatosis was diagnosed by ultrasound, and SCA was defined by carotid plaques or increased intima-media thickness. Liver fibrosis was evaluated using the fibrosis-4 index and elastography.
Results:
SCA was identified in 13.5%. MASLD and MetALD were significantly associated with SCA in models adjusted for demographic and lifestyle factors (adjusted odds ratio [aOR], 1.26;95% confidence interval [CI], 1.19 to 1.33; aOR, 1.43; 95% CI, 1.30 to 1.58; respectively, p<0.001for both). However, these associations attenuated and lost statistical significance when metabolic risk factors were further adjusted. The risk of SCA increased with greater hepatic steatosis and liver fibrosis severity. In patients with MASLD, aORs were 1.70 (hepatic steatosis index >36),1.23 (fibrosis-4 index ≥1.3), and 1.78 (liver stiffness measurement ≥5.6 kPa), compared to indi-viduals without MASLD. Similar trends were observed in the MetALD group. Additionally, hyper-tension and clustering of ≥3 cardiometabolic risk factors were significantly associated with SCA inthe MASLD group, supporting the role of metabolic burden in SCA development.
Conclusions
MASLD and MetALD were associated with increased SCA risk, particularly in individuals with hepatic steatosis and fibrosis. These findings suggest that metabolic burden and liver disease severity jointly contribute to subclinical atherosclerosis risk.
5.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.
7.Multifocal IOL Power Calculation Using the Barrett True-K Formula After Radial Keratotomy: A Case Report
Ji Hoon BAN ; Myung Ho CHO ; Jae Hyun KIM ; Jong Soo LEE
Journal of the Korean Ophthalmological Society 2026;67(2):67-72
Purpose:
To report the clinical utility of the Barrett True-K formula in predicting multifocal intraocular lens (IOL) power in a patient with corneal deformation caused by radial keratotomy (RK), where postoperative refractive power prediction is challenging.Case summary: A 61-year-old male who underwent RK 30 years ago presented for cataract surgery. Slit-lamp examination showed eight RK incisions in each eye. Refractive error was +3.25 D sph; -1.75 D cyl, axis 70 in the right eye and +2.75 D sph; -1.00 D cyl, axis 110 in the left. Uncorrected visual acuity was 0.32 in the right eye and 0.63 in the left. IOL power was calculated using the Barrett True-K formula on the IOLMaster 700, with a target refraction of -0.25 D, and a multifocal IOL was implanted. Six months after cataract surgery, both eyes achieved a fraction close to emmetropia, with best corrected visual acuity of 0.63 in the right eye and 1.0 in the left. No significant refractive shifts or other complications were observed during surgery or 6-month follow-up.
Conclusions
The Barrett True-K formula, which measures the actual corneal refractive power to compensate for corneal deformation, is expected to be clinically useful for multifocal IOL implantation during cataract surgery in eyes after RK.
8.Effectiveness of low-dose mepolizumab in refractory eosinophilic granulomatosis with polyangiitis: systemic steroid use and remission
Mi-Ae KIM ; Ji-Hyun LEE ; Eun-Kyung KIM ; Jung-Hyun KIM ; Jisoo PARK ; Se Hee LEE ; Tae-Bum KIM
The Korean Journal of Internal Medicine 2026;41(1):163-174
Background/Aims:
This study investigated the clinical efficacy of low-dose mepolizumab (100 mg) in controlling severe eosinophilic asthma, aiming to induce eosinophilic granulomatosis with polyangiitis (EGPA) remission and reduce systemic steroid usage. Additionally, we constructed a basic frame for our longitudinal EGPA cohort by collecting serial blood samples before, during, and after mepolizumab treatment in EGPA patients.
Methods:
We conducted a 2-year prospective observational cohort study in patients with uncontrolled severe eosinophilic asthma and refractory EGPA who used systemic steroids (≥ 7.5 mg/day of prednisolone) or other immunosuppressant drugs for at least 6 months. All patients were treated with 100 mg of mepolizumab every 4 weeks for 1 year to control severe eosinophilic asthma and then were followed for an additional 1 year to monitor their disease course. We analyzed total systemic steroid use and EGPA remission/relapse during the study period.
Results:
Three EGPA patients were included in this study and completed 16 study visits over a 2-year period. After 1 year of treatment with mepolizumab (100 mg monthly), all 3 patients were able to reduce their maintenance dose of systemic steroids, with 2 patients completely discontinuing use. These 2 patients achieved EGPA remission during mepolizumab treatment, and their remission status remained stable for 1 year after they stopped receiving the medication.
Conclusions
Low-dose mepolizumab treatment demonstrated clinical efficacy in reducing the maintenance dose of systemic steroids required for severe refractory EGPA. While not all patients achieved EGPA remission with low-dose mepolizumab, some did, and their remission persisted even after treatment discontinuation.
9.Risk factors for bleeding from gastric antral vascular ectasia
Sung Hyun CHO ; Jinyoung KIM ; Hee Kyong NA ; Ji Yong AHN ; Jeong Hoon LEE ; Kee Wook JUNG ; Do Hoon KIM ; Kee Don CHOI ; Ho June SONG ; Gin Hyug LEE ; Hwoon-Yong JUNG
The Korean Journal of Internal Medicine 2026;41(1):74-84
Background/Aims:
Gastric antral vascular ectasia (GAVE) is a rare but important cause of gastrointestinal (GI) bleeding. The clinical course of GAVE is not well-known, and recurrent bleeding from GAVE is a therapeutic challenge. Therefore, we investigated the clinical course of GAVE and identified the risk factors for bleeding from it.
Methods:
We retrospectively reviewed the records of patients diagnosed with GAVE using upper GI endoscopy at Asan Medical Center between January 2004 and December 2019 and evaluated the clinical course and risk factors for bleeding from GAVE.
Results:
Of the 348 patients (mean age, 62.3 ± 10.7 years; male, 62%), bleeding from GAVE occurred in 123 (35%) patients during follow-up (median, 17.3 months; interquartile range [IQR], 4.2–46.6). GI bleeding from GAVE was significantly associated with Child–Pugh class B or C liver cirrhosis (odds ratio [OR], 2.55; 95% confidence interval [CI], 1.57–4.16), chronic kidney disease (CKD) (OR, 2.77; 95% CI, 1.52–5.07), use of antithrombotic agents (OR, 2.34; 95% CI, 1.13–4.82), and involvement of the duodenal bulb (OR, 3.21; 95% CI, 1.76–5.86). Rebleeding occurred in 39 of 123 patients (32%), in whom CKD (OR, 2.55; 95% CI, 1.12–5.81) was significantly associated with rebleeding. Endoscopic hemostasis was most commonly performed using argon plasma coagulation, and the median number of endoscopic hemostasis performed was 2 (IQR, 1–3).
Conclusions
A careful follow-up for bleeding is needed in GAVE patients with liver cirrhosis, CKD, use of antithrombotic agents, and duodenal bulb involvement.
10.Fetal development of chromogranin A-positive gastrointestinal endocrine cells revisited: a histological study using human fetuses
Ji Hyun KIM ; Zhe-Wu JIN ; Eri MIYAMOTO ; Sakiko TAKAHASHI ; Sayako SUZUKI ; Gen MURAKAMI ; Shin-ichi ABE
Anatomy & Cell Biology 2026;59(1):82-93
Initial gastrointestinal endocrine cells (GIECs) likely appear at the proximal and distal sites of abdominal intestines and may take a close topographical relation with neural elements in the gut. We examined immunohistochemically-stained sections from 10 fetuses at approximately 8–18 weeks of gestational age (36–155 mm of crown-rump length). Irrespective of whether physiological herniation was present (early 5 specimens) or absent (the other 5), the duodenum and jejunum had well-developed mucosa with villi containing abundant flask-like chromogranin-positive cells. In the earlier 5 specimens, the rectum, standing up to a level of the umbilicus, had a lumen and villi with a few positive cells, but the colon carried neither the lumen or chromogranin-positive cells. The initial GIECs seemed to appear in the basal payer of the epithelium at the distal and proximal foci depending on double pathways of neural crest cell migration. Less number of the colic chromograninpositive cells, more than 5-times difference in density relative to small intestine, was seen in the larger 5 specimens. The appearance of GIECs was delayed at the anal transitional zone (a border area between the columnar and squamous epithelia).The reactivity of neuronal nitric oxide synthase was restricted in the myenteric plexus, whereas clusters of slender calretininpositive cells existed in the lamina propria or core of villi in the duodenum and colon. Relatively small, round or oval positive cells were also seen in the basal layer of the columnar epithelium. Therefore, calretinin-positive cells might exist closely to GIECs in the developing villi.

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