Background: Erythema multiforme (EM) is typically a self-limited, acute hypersensitivity reaction. However, a subset of patients experiences chronic, recurrent episodes, for which clinical features and treatment strategies differ depending on the underlying etiology, especially in herpes simplex virus (HSV)-associated cases. Objective: To investigate the clinical and phenotypic features of chronic recurrent EM and assess treatment responses, with a focus on differences based on HSV association. Methods: This retrospective study included pathology-confirmed cases of suspected EM from 2010 to 2023. Forty patients with chronic EM (≥3 recurrences or persistent disease for ≥12 months) were included. Clinical, histopathologic, and serologic data were analysed.Patients were stratified into herpes simplex virus-associated erythema multiforme (HAEM) and non-HAEM groups. Clustering analysis was performed to identify clinical phenotypes.Treatment responses to antivirals and immunomodulators were evaluated. Results: Of the 40 patients, 24 (60%) were classified as HAEM. HAEM patients showed more mucosal involvement, smaller targetoid lesions, and acral predominance, while nonHAEM patients had larger, coalescing lesions with more trunk involvement. Cluster analysis supported HSV as the major discriminating factor. Antiviral agents were effective in 87.5% of HAEM cases but ineffective in 76.9% of non-HAEM patients. Immunosuppressants such as cyclosporine and mycophenolate mofetil showed variable responses. Baricitinib induced complete remission in all 3 refractory cases. Conclusion HSV association defines a distinct clinical subtype of chronic recurrent EM, with differences in lesion morphology, distribution, and treatment response. Recognizing these patterns may guide targeted therapeutic strategies, including the potential use of Janus kinase inhibitors in refractory cases.

Background: Despite widespread vaccination efforts against severe acute respiratory syndrome coronavirus 2, variants with increased transmissibility or immune evasion continue to emerge, posing a considerable challenge. Understanding the immunological factors associated with coronavirus disease (COVID-19) progression is essential for improving patient management and treatment strategies. We explored the dynamic changes in the peripheral white blood cell (WBC) profile, including T lymphocyte subsets, to assess their potential as predictors of disease severity and progression. Methods: Two hundred fifty-eight patients hospitalized for confirmed COVID-19 were classified into four sub-cohorts based on changes in disease severity over 7 days. WBC parameters, including absolute neutrophil, total lymphocyte, and T cell subset counts, and the neutrophil-to-lymphocyte ratio (NLR) were assessed at admission and after 7 days. Results: Patients with persistent mild-to-moderate illness exhibited a marked increase in the lymphocyte count and a decrease in the NLR over time. In contrast, patients with sustained severe-to-critical illness showed an increasing WBC count without a corresponding increase in the lymphocyte count, in addition to a marked elevation in the NLR. Patients whose condition improved from severe-to-critical to mild-to-moderate illness showed increased cluster of differentiation (CD)3+ and CD4+ T cell counts and an elevated CD4/CD8 ratio, whereas the NLR did not significantly change. Conclusions The early-phase dynamics of T cell subsets may serve as a useful biomarker of disease severity and recovery in patients with COVID-19. Monitoring these immunological changes may help support clinical decision-making and inform the timing of therapeutic interventions.

Purpose: This study explored the experiences of physicians and nurses providing end-oflife care in Korean acute care hospitals. It aimed to identify the challenges faced in caring for dying patients and to suggest strategies for improving hospital-based end-of-life care. Methods: A qualitative exploratory design was employed using focus group interviews.Eleven healthcare professionals (five physicians and six nurses) working in tertiary or general hospitals participated in the study between July and August 2018. The interviews were conducted using a semi-structured guide covering seven thematic areas. All sessions were audio-recorded, transcribed verbatim, and analyzed thematically following Braun and Clarke’s framework. Results: Six major themes emerged: (1) communication with patients and families, (2) physical care for dying patients, (3) psychological and spiritual support, (4) hospital environment and system constraints, (5) moral distress and emotional burden on healthcare providers, and (6) suggestions for improvement. The participants described difficulties in open communication, limited resources for comfort care, emotional strain from invasive treatment at the end of life, and the absence of standardized institutional protocols.They emphasized the need for structured communication training, multidisciplinary collaboration, and integration of palliative care principles into acute care practice. Conclusion Physicians and nurses play a pivotal yet emotionally demanding role in providing end-oflife care in acute hospitals. Institutional reforms, including education, protocol development, and supportive environments, are essential to ensuring dignified, patient-centered care and sustain healthcare providers in their professional roles.

Background: Epidermal growth factor (EGF) is widely applied in dermatology for its regenerative effects; however, its clinical utility is limited by low stability and high production costs.To overcome these limitations, we developed a novel probiotic-derived epidermal growth factor (pEGF) by engineering Pediococcus pentosaceus CBT SL4 to express and secrete EGF. Objective: To investigate the anti-photoaging effects of topical pEGF in a ultraviolet B (UVB)-irradiated mice by assessing histological and molecular changes related to collagen synthesis, extracellular matrix (ECM) remodeling, oxidative stress, and inflammation. Methods: SKH1 hairless mice were exposed to UVB for twelve weeks to induce photoaging and treated with topical 10% pEGF cream from week 9 to 12. Skin samples were analyzed using dermoscopy, histology, immunohistochemistry, quantitative real-time polymerase chain reaction, western blotting, and proteomics to evaluate morphological and molecular alterations in ECM components and inflammatory markers. Results: Topical pEGF treatment improved skin texture and reduced wrinkles. Histological evaluation revealed that EGF significantly attenuated UVB-induced epidermal thickening and restored collagen density, with the strongest effects observed in the pEGF group. Molecular analysis showed downregulation of matrix metalloproteinases (MMPs; MMP-1, MMP-3), upregulation of collagen (type I collagen, type III collagen) and tissue inhibitors of metalloproteinases (TIMPs; TIMP-1, TIMP-2). Additionally, pEGF reduced pro-inflammatory cytokines (tumor necrosis factor-α, interleukin-1β) and oxidative stress markers. Conclusion pEGF demonstrated potent anti-photoaging effects through ECM restoration, inflammation modulation, and barrier reinforcement. These findings support the therapeutic potential of pEGF as a stable, cost-effective alternative to conventional EGF in dermatological applications.

Purpose: Based on the KEYNOTE-522 study, neoadjuvant pembrolizumab plus chemotherapy has become the standard treatment for early-stage triple-negative breast cancer (TNBC).This study evaluated the real-world efficacy, safety, and predictors of pathologic complete response (pCR) in Korean patients. Methods: We conducted a retrospective cohort study of 174 patients with early-stage TNBC who received the KEYNOTE-522 regimen (neoadjuvant pembrolizumab plus paclitaxel and carboplatin, followed by doxorubicin and cyclophosphamide) at a tertiary cancer center between August 2022 and July 2024. We assessed the primary endpoints, including pCR rate and event-free survival (EFS). We performed univariable and multivariable logistic regression analyses to identify independent predictors of pCR. Results: The median patient age was 50 years (range, 24–74 years). The clinical stages were II and III in 79.3% and 20.1% of patients, respectively, and 10.9% had clinical N3 disease. The overall pCR rate was 62.1%, and the N3 subgroup had a pCR rate of 47.4%. On multivariable analysis, high baseline Ki-67 expression (≥ median, 75%) was significantly associated with pCR (odds ratio, 2.84; 95% confidence interval, 1.45 to 5.66; p = 0.002). At a median followup of 18.4 months, the 12-month EFS rate was 97.4%, with significantly superior outcomes observed in patients who achieved pCR compared with those who did not achieve pCR (100% vs. 93.1%, p = 0.007). The treatment completion rate was 92.0%, and immune-related adverse events occurred in 13.8% of patients. Conclusion In this real-world analysis of one of the largest Asian cohorts of patients with earlystage TNBC treated with neoadjuvant pembrolizumab, the KEYNOTE-522 regimen demonstrated substantial efficacy and manageable toxicity, consistent with the original trial findings.

Purpose: This study compared the efficacy of different irrigation methods for the removal of Ca(OH)2 paste from the root canal. Materials and Methods: The root canals of 75 human mandibular premolars with standardized 15-mm canal lengths were prepared using nickel-titanium rotary files. After drying, the canals were filled with Ca(OH)2 paste. The teeth were divided into five groups: Control group (Group C), conventional irrigation; Group EA, sonic activation (EndoActivator); Groups EQA and EQB, sonic activation (EQ-S with metal tips A and B, respectively); and Group EU, ultrasonic activation (EndoUltra).The Ca(OH)2 paste volume before and after irrigation was measured using micro-computed tomography (CT) images. One specimen from each group was bisected along the long axis, and the canal walls were evaluated at 100× magnification using a scanning electron microscope. Statistical analyses were performed using Kruskal-Wallis and Mann-Whitney U tests. Results: Overall, Ca(OH)2 paste removal was higher in Group EQA than in Group C. In the coronal third, removal rate was higher in Group EQA than in Group C. In the middle third, Groups EQB and EU outperformed Group C. Removal from the apical third was higher in Group EQA than in Group C. All groups showed greater removal from the coronal and middle thirds than from the apical third. Conclusion Sonic and ultrasonic irrigation methods demonstrated higher efficacy than conventional irrigation method for the removal of Ca(OH)2 paste from the root canal. All groups demonstrated better effectiveness in removal from the coronal and middle thirds than from the apical third.

The efficacy of clarithromycin-containing triple therapy (TT) against Helicobacter pylori has declined in Korea, with recent first-line eradication rates falling below 70%. Clarithromycin resistance exceeded 30%, undermining the standard regimen for H. pylori. These trends necessitate a change in the treatment strategy. This review analyzed the shift proposed in the draft of the 2025 Korean H. pylori guidelines. We examined the rationale for abandoning TT as a first-line empirical therapy and the establishment of a new dual-pillar strategy: 1) the declining role of clarithromycin-containing TT as a first-line treatment and 2) polymerase chain reaction (PCR)-based tailored therapy as the recommended precision approach. We explored the 1) emergence of new empirical regimen options, 2) application of tailored therapy, and 3) adoption of potassium-competitive acid blockers (P-CABs). Empirical regimens have shifted toward four-drug combinations to achieve higher cure rates. Concomitant therapy (proton-pump inhibitor [PPI] or P-CAB+amoxicillin+clarithromycin+metronidazole) offers high efficacy but raises concerns about antibiotic overuse. As a compromise, bismuth-augmented triple regimens (adding bismuth to TT) are now recommended; these modified quadruple therapies (e.g., PACB: PPI+amoxicillin+clarithromycin+bismuth, or PAMB: PPI+amoxicillin+metronidazole+bismuth) significantly improve eradication rates without requiring a third antibiotic class. Regarding tailored therapy, PCR-based domestic clinical research data consistently achieves ≥90% cure rates in first-line treatment—markedly higher than empirical TT in Korea. Economic analyses supported the cost-effectiveness of this approach. The guideline algorithm for salvage therapy was clarified. Bismuth quadruple therapy has been confirmed as the standard second-line treatment. For third-line therapy, we analyzed the efficacy of levofloxacin-based regimens, rifabutin-based therapy, and bismuth add-on therapy with two previously unused antibiotics. The 2025 Korean guidelines establish quadruple therapies as the new standard through a dual strategy: pragmatic empirical treatment and PCR-guided tailored therapy, with P-CABs and bismuth-based regimens as key components.

Purpose: Since 1995, the Korean Gastric Cancer Association (KGCA) has been periodically conducting nationwide surveys on patients with surgically treated gastric cancer. This study details the results of the survey conducted in 2023. Materials and Methods: The survey was conducted from March to December 2024 using a standardized case report form. Data were collected on 86 items, including patient demographics, tumor characteristics, surgical procedures, and surgical outcomes. The results of the 2023 survey were compared with those of previous surveys. Results: Data from 12,751 cases were collected from 66 institutions. The mean patient age was 64.6 years, and the proportion of patients aged ≥71 years increased from 9.1% in 1995 to 31.7% in 2023. The proportion of upper-third tumors slightly decreased to 16.8% compared to 20.9% in 2019. Early gastric cancer accounted for 63.1% of cases in 2023.Regarding operative procedures, a totally laparoscopic approach was most frequently applied (63.2%) in 2023, while robotic gastrectomy steadily increased to 9.5% from 2.1% in 2014.The most common anastomotic method was the Billroth II procedure (48.8%) after distal gastrectomy and double-tract reconstruction (51.9%) after proximal gastrectomy in 2023.However, the proportion of esophago-gastrostomy with anti-reflux procedures increased to 30.9%. The rates of post-operative mortality and overall complications were 1.0% and 15.3%, respectively. Conclusions The results of the 2023 nationwide survey demonstrate the current status of gastric cancer treatment in Korea. This information will provide a basis for future gastric cancer research.

Gastric cancer is one of the most common cancers in both Korea and worldwide. Since 2004, the Korean Practice Guidelines for Gastric Cancer have been regularly updated, with the 4th edition published in 2022. The 4th edition was the result of a collaborative work by an interdisciplinary team, including experts in gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology, and guideline development methodology. The current guideline is the 5th version, an updated version of the 4th edition. In this guideline, 6 key questions (KQs) were updated or proposed after a collaborative review by the working group, and 7 statements were developed, or revised, or discussed based on a systematic review using the MEDLINE, Embase, Cochrane Library, and KoreaMed database. Over the past 2 years, there have been significant changes in systemic treatment, leading to major updates and revisions focused on this area.Additionally, minor modifications have been made in other sections, incorporating recent research findings. The level of evidence and grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation system. Key factors for recommendation included the level of evidence, benefit, harm, and clinical applicability. The working group reviewed and discussed the recommendations to reach a consensus. The structure of this guideline remains similar to the 2022 version.Earlier sections cover general considerations, such as screening, diagnosis, and staging of endoscopy, pathology, radiology, and nuclear medicine. In the latter sections, statements are provided for each KQ based on clinical evidence, with flowcharts supporting these statements through meta-analysis and references. This multidisciplinary, evidence-based gastric cancer guideline aims to support clinicians in providing optimal care for gastric cancer patients.