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.

Background and Objectives: Clinical characteristics and outcomes in acute heart failure (AHF) vary by phenotype. We assessed phenotype-specific features, treatment patterns, and outcomes in a nationwide Korean cohort. Methods: The Korean Heart Failure III registry prospectively enrolled 7,351 AHF admissions at 47 hospitals. Among 6,777 patients with available left ventricular ejection fraction (EF), phenotypes were defined as heart failure with reduced EF (HFrEF, ≤40%), mildly reduced EF (HFmrEF,41–49%), or preserved EF (HFpEF, ≥50%). The primary endpoint was a 12-month composite of all-cause death or heart transplantation, evaluated from index admission and, among hospital survivors, from discharge. We used inverse probability weighting (multinomial generalized boosted models with stabilized, trimmed weights) and weighted Cox proportional-hazards models to estimate hazard ratios (HRs). Results: Phenotype distribution was 58.9% HFrEF, 13.6% HFmrEF, and 27.5% HFpEF. Crude 12-month composite rates from index admission were 13.4% (HFrEF), 12.7% (HFmrEF), and 16.8% (HFpEF). After weighting, from index admission, HFmrEF (HR, 0.892; 95% confidence interval [CI], 0.731–1.088) and HFpEF (HR, 1.101; 95% CI, 0.939–1.291) did not differ from HFrEF; from discharge, HFpEF had modestly higher risk (HR, 1.207; 95% CI, 1.008–1.445) whereas HFmrEF did not (HR, 1.039; 95% CI, 0.844–1.279). Hyponatremia and chronic kidney disease were consistent adverse markers, while angiotensin-converting enzyme inhibitor/ angiotensin II receptor blocker use at discharge was protective. Conclusions Across the EF spectrum, phenotypes showed distinct profiles and risk. Postdischarge risk was modestly higher in HFpEF, supporting phenotype-tailored care and systematic discharge optimization in Korean patients with AHF.

Cervicofacial necrotizing fasciitis (CNF) of the face is a rare and potentially life-threatening bacterial infection that requires immediate intervention. CNF involving the buccal fat pad particularly demands surgical drainage, with attention to the surrounding anatomical structures to prevent vascular or nerve damage. In this study, we reviewed the anatomy of buccal fat pads to suggest appropriate surgical approaches. A retrospective chart review was conducted on seven patients with CNF who had a buccal fat pad abscess requiring surgical incision and drainage between January 2022 and August 2023. Abscesses within the central buccal fat pad and its pterygoid extensions were drained via intraoral incisions. Abscesses in the temporal extension were addressed by the Dingman approach. All patients underwent our surgical drainage regimen combined with proper intravenous antibiotics, leading to successful treatment of CNF without significant functional sequelae, with an average stay of 18.71 days. The buccal fat pad, which corresponds to the deep space of the face, is surrounded by vital structures such as the facial artery, vein, nerve, and parotid duct. When treating abscesses in the buccal fat pad, it is important to understand the relationship of the fat pad to other vital structures for optimal outcomes.

Purpose: One of the novel cell sources of cell-based liver regenerative medicine is human chemically-derived hepatic progenitors (hCdHs). We previously established this cell by direct hepatocyte reprogramming with a combination of small molecules (hepatocyte growth factor, A83-01, CHIR99021). However, there have been several issues concerning the cell’s stability and maintenance, namely the occurrences of epithelial-mesenchymal transition (EMT) that develop fibrotic phenotypes, resulting in the loss of hepatic progenitor characteristics. These hepatic progenitor attributes are thought to be regulated by SOX9, a transcription factor essential for hepatic progenitor cells and cholangiocytes. Methods: To suppress the fibrotic phenotype and improve our long-term hCdHs culture technology, we utilized the epigenetic modulating drugs DNA methyltransferase inhibitor (5-azacytidine) and histone deacetylase inhibitor (sodium butyrate) that have been reported to suppress and revert hepatic fibrosis. To confirm the essential role of SOX9 to our cell, we used clustered regularly interspaced short palindromic repeats-interference (CRISPRi) to repress the SOX9 expression. Results: The treatment of only 5-azacytidine significantly reduces the fibrosis/mesenchymal marker and EMT-related transcription factor expression level in the early passages. Interestingly, this treatment also increased the hepatic progenitor markers expression, even during the reprogramming phase. Then, we confirmed the essential role of SOX9 by repressing the SOX9 expression with CRISPRi which resulted in the downregulation of several essential hepatic progenitor cell markers. Conclusion These results highlight the capacity of 5-azacytidine to inhibit EMT-driven hepatic fibrosis and the significance of SOX9 on hepatic progenitor cell stemness properties.

Purpose: The use of advanced energy devices for mastectomy and axillary lymph node dissection can reduce perioperative blood loss, seroma formation, and drainage duration/volume. Retraction using fiberoptic retractors can help visualize deep and narrow surgical fields. We aimed to compare the postoperative outcomes between single-incision breast-conserving surgery (SIBCS) and conventional breast-conserving surgery (CBCS) with axillary staging using advanced energy devices and conventional equipment, respectively. Materials and Methods: We retrospectively reviewed the medical records of 244 patients who underwent BCS with axillary surgery between March 2018 and September 2019 at Severance Hospital. The patients were grouped based on the device used to aid in axillary staging: CBCS group (n=117) used conventional electrocautery; and SIBCS group (n=127) used advanced energy devices and fiberoptic retractors. The two groups were compared for postoperative outcomes. Results: The mean patient age was 55.9 and 53.1 years in the CBCS and SIBCS groups, respectively. Incision size was significantly smaller in the SIBCS group than in the CBCS group (6.3±2.1 cm vs. 7.5±2.5 cm, p=0.044). There were no significant differences between the two groups in terms of operating time (126.0±40.0 min vs. 127.0±63.0 min, p=0.828), operative blood loss (11.0±31.0 mL vs. 7.0±18.0 mL, p=0.100), drainage duration (7.0±3.0 d vs. 8.0±4.0 d, p=0.288), and complications (1.70% vs. 2.36%, p=0.523). Conclusion Using advanced energy devices for SIBCS with axillary staging reduced incision size and provided better cosmetic outcomes compared to those using the conventional method. Advanced energy devices may offer better surgical outcomes in patients who undergo BCS with axillary staging.

Nontuberculous mycobacteria (NTM) is a type of bacteria that typically infects the pulmonary system, and NTM–central nervous system (CNS) infection, which occurs in the brain, is a very rare disease. A 64-year-old female patient presented with seizures as the main symptom and was found to have a mass of less than 1 cm in the right temporal lobe with accompanying edema. Although diseases such as tumor metastasis and parasitic cyst were suspected, the patient underwent a surgical resection, and NTM-CNS infection with abscess was diagnosed through biopsy. Antibiotic treatment was initiated after surgery, and the patient has been followed up without any significant symptoms. In this report, we review a rare case of NTM-CNS infection and discuss the understanding and treatment of this disease.

Background: This study aimed to compare the biomechanical strength of 360° scapholunate interosseous ligament (SLIL) reconstruction only using an artificial material (AM), double dorsal limb (DDL) SLIL reconstruction only using AM, and the modified Brunelli technique (MBT) with ligament. Methods: Eight cadaver wrists were used for this study. The SL interval, SL angle, and radiolunate (RL) angle were recorded with MicroScribe. The SL distance was measured after dividing the volar and dorsal aspects. We utilized four different wrist postures (neutral, flexion, extension, and clenched fist) to compare five conditions: intact wrist, SLIL resection, 360° SLIL reconstruction using AM, DDL SLIL reconstruction using AM, and MBT SLIL reconstruction with ligament. Results: The dorsal SL distance in the SLIL resection was widened in all wrist positions. The dorsal SL distance was restored with all three techniques and in all wrist positions. The volar SL distance in the wrist extension position was widened in the SLIL resection condition. The volar SL distance was restored in the extension position after 360° SLIL reconstruction using AM condition. There were no statistically significant differences in SL and RL angles among the conditions. Conclusions All three reconstruction techniques could restore the dorsal SL distance. However, only the 360° SLIL reconstruction using AM restored the volar SL distance in the wrist extension position. DDL SLIL reconstruction using AM tended to overcorrect, whereas 360° SLIL reconstruction using AM effectively stopped volar SL interval widening.

Background: : Effective communication between doctors and patients is very important not only for diagnosis and treatment but also for building trust. Although teaching communication skills is very important in medical schools, there are limitations such as the number of students and the uncertainty of the patient population. Therefore, this study evaluates the effect of Fishbowl method to teach communication skills to medical students, which involves the medical students communicating with standardized patients in front of a large classroom and being observed by rest of the students. Methods: : This study involves 10 weeks of educating 126 fourth grade medical students and graduates. During this period, total 8 classes were taken by subjects, where each class lasts 2 hours and is conducted by observing treatments of the standardized patients on 14 clinical topics by randomly selected medical students and giving feedback on the communication skills of the selected medical students. The educational effect was evaluated based on the scores of the clinical performance examination before and after the classes. Results: : The scores assessed for medical history taking before and after the training are increased by 2.45 (p<0.001) and the scores for patient-doctor relationship is increased by 7.56 (p<0.001). Conclusions : It is expected to improve the communication skills of medical students by large scale lectures with standardized patients.

Purpose: The current standard chemotherapy for advanced biliary tract cancer (BTC) has limited benefit,and novel therapies need to be investigated. Materials and Methods: In this prospective cohort study, programmed death ligand-1 (PD-L1)–positive BTC patientswho progressed on first-line gemcitabine plus cisplatin were enrolled. Pembrolizumab 200mg was administered intravenously every 3 weeks. Results: Between May 2018 and February 2019, 40 patients were enrolled. Pembrolizumab wasgiven as second-line (47.5%) or  third-line therapy (52.5%). The objective response ratewas 10% and 12.5% by Response Evaluation Criteria in Solid Tumor (RECIST) v1.1 andimmune-modified RECIST (imRECIST) and median duration of response was 6.3 months.Among patients with progressive disease as best response, one patient (1/20, 5.0%)achieved complete response subsequently. The median progression-free survival (PFS) andoverall survival (OS) were 1.5 months (95% confidence interval [CI], 0.0 to 3.0) and 4.3months (95% CI, 3.5 to 5.1), respectively, and objective response per imRECIST was significantlyassociated with PFS (p < 0.001) and OS (p=0.001). Tumor proportion score  50%was significantly associated with higher response rates including the response after pseudoprogression(vs. < 50%; 37.5% vs. 6.5%; p=0.049). Conclusion Pembrolizumab showed modest anti-tumor activity in heavily pretreated PD-L1–positiveBTC patients. In patients who showed objective response, durable response could beachieved.