Flow cytometric lymphocyte subset analysis (FCLSA) is essential for assessing immune status across various diseases and clinical settings. We surveyed current clinical laboratory practices related to FCLSA to establish a baseline reference for future standardization in Korea. Nine university hospitals actively performing FCLSA responded to the 22-question survey, which covered seven categories of laboratory practice. These hospitals used commercial reagent antibody kits from either Beckton Dickinson Biosciences (N = 4) or Beckman Coulter Diagnostics (N = 5). Most hospitals performed daily instrument setup and scheduled maintenance every 2–6 months. Two levels of commercial quality control materials were routinely used each day. Sample and reagent antibody volumes varied across hospitals, even when the same reagent kit was used. Acquired cell counts ranged from 5 × 10 3 to 5 × 10 4 cells, with two hospitals adjusting counts based on the cell type analyzed. Most laboratories reported percentages and general opinions; some additionally reported white blood cell and lymphocyte counts, along with lymphocyte percentages. This is the first comprehensive survey on the clinical laboratory practice of FCLSA in Korea.Standardization of FCLSA should be accelerated to ensure reliable and reproducible results.

Purpose: This study aimed to examine nursing management competencies among nurses working in national specialized hospitals, to identify competency development needs and influencing factors, and to provide foundational data for the development of educational and competency-enhancement programs. Methods: A mixed-methods design was employed. Quantitative data were collected via an online survey of 162 nurses from five national specialized hospitals from January 10 to February 10, 2025, and qualitative data were obtained through in-depth interviews with 20 participants from March 7 to April 16, 2025. Quantitative data were analyzed using descriptive statistics, independent t-tests, analysis of variance, importance–performance analysis, the Borich Needs Assessment, the Locus for Focus model, and multiple regression analysis. Qualitative data were analyzed using content analysis with ATLAS.ti. Results: The mean performance score for nursing management competencies was 3.56±0.71 on a 5-point scale. Customer orientation received the highest score (4.03±0.78), whereas business and marketing received the lowest score (2.92±1.03). Across needs-assessment models, leadership, nursing ethics and law, quality improvement, and standard development consistently emerged as high-priority areas. In multiple regression analysis, the nursing work environment was the only factor significantly associated with nursing management competency performance (β=.33, p<.001). Qualitative content analysis corroborated these findings and identified three facilitator themes and three barrier themes. Conclusion Nursing management competency performance among nurses in national specialized hospitals was associated with the nursing work environment, including organizational conditions. These findings underscore the importance of organizational support and suggest that competency-based education should be redesigned to prioritize high-need competency areas. This study provides a foundation for developing educational interventions and programs to enhance nursing management capacity.

Background/Aims: Spinal cord injury (SCI) frequently impairs defecation, severely affecting the quality of life. This study examines compensatory neural remodeling after SCI, focusing on basal colonic contractility, neural responses to electrical field stimulation, and alterations in excitatory cholinergic and inhibitory nitrergic pathways. Methods: Female Sprague–Dawley rats underwent either sham surgery or T10 spinal cord transection and were categorized into 3 groups: sham, 1-week post-SCI (acute), and 4-week post-SCI (chronic). Colonic contractility was assessed in an organ bath using electrical field stimulation in the presence of a nitric oxide synthase inhibitor. Neural protein expression was analyzed by immunofluorescence and Western blotting. Results: SCI produced region- and time-dependent impairments in colonic contractility, with distinct alterations in the proximal circular and longitudinal muscles across acute and chronic phases. Neural excitability shifted dynamically, showing enhanced excitatory activity in the proximal longitudinal muscle at 1-week and the distal circular muscle at 4-week post-SCI. Protein analysis revealed increased neuronal nitric oxide synthase in the proximal colon, decreasedsoluble guanylyl cyclase in the distal colon, upregulated muscarinic M3 receptor in the proximal colon, and reduced vaso-active intestinal peptide receptor 1 in both proximal and distal regions. Conclusion SCI induces spatiotemporal remodeling of excitatory and inhibitory neural pathways, contributing to colonic dysmotility and revealing potential targets for therapeutic intervention.

Vitamin B6 is an essential water-soluble vitamin involved in amino acid metabolism, neurotransmitter synthesis, heme biosynthesis, and one-carbon metabolism. Its active form, pyridoxal-5′-phosphate (PLP), serves as a coenzyme in more than 100 enzymatic reactions and is critical for maintaining metabolic homeostasis, immune regulation, and nervous system function. Epidemiological studies have reported inverse associations between vitamin B6 intake or the circulating PLP concentrations and the risk of cardiovascular disease, certain cancers, and diabetes-related metabolic dysfunction. The proposed mechanisms include the modulation of inflammation, oxidative stress, and homocysteine metabolism. Nevertheless, most available evidence is derived from observational studies conducted in Western or non-Korean populations, limiting generalizability and precluding revisions to current intake recommendations based on the chronic disease outcomes. Relevant epidemiological studies, mechanistic evidence, and recent international and national risk assessment reports were reviewed. Although excessive intake from habitual diets is uncommon, the increasing use of dietary supplements has raised concerns regarding chronic high-dose exposure. Accumulating human evidence suggests that long-term supplementation with high pyridoxine doses may induce sensory peripheral neuropathy, even at lower intake levels than previously assumed. Accordingly, recent international risk assessments, including the 2023 re-evaluation by the European Food Safety Authority, have proposed substantially lower Tolerable Upper Intake Level (UL) using benchmark dose modeling based on human data. In the 2025 Dietary Reference Intakes for Koreans, the UL for adults was set at 50 mg/day, reflecting the updated safety evidence and domestic supplement use patterns, while the recommended intake levels were maintained based on the established metabolic requirements. Further population-specific prospective studies and long-term safety data are needed to refine intake guidance and strengthen evidence-based risk management strategies in Korea.

This study aimed to determine the prevalence of human epidermal growth factor receptor 2 (HER2)–ultralow breast cancer among cases initially classified as HER2 immunohistochemistry (IHC) 0 and assess interobserver variability in interpreting low-level HER2 expression. Methods: In this multicenter retrospective study, all invasive breast cancer cases diagnosed between January and December 2022 across 10 Korean institutions were retrieved. Institutional pathologists reexamined HER2 IHC slides originally reported as IHC 0 according to the 2018 American Society of Clinical Oncology/College of American Pathologists guidelines and reclassified them as HER2-null (0), HER2-ultralow (0+), or HER2-low (1+). Slides from 10% of HER2-null and HER2-ultralow cases were digitized for central review and independently assessed by two pathologists, with discrepancies resolved by consensus. Results: Among 8,026 cases, 2,836 cases (35.5%) were initially reported as IHC 0. Upon re-review, 1,673 (59.0%), 1,139 (40.2%), and 24 (0.8%) cases were reclassified as HER2-null, HER2-ultralow, and HER2-low, respectively. The prevalence of HER2-ultralow breast cancer varied considerably across institutions (23.7%–78.1%). Central review of 268 digitized cases showed concordance in 193 cases (72.0%). Among the 75 discordant cases, 54 tumors (72.0%) were upgraded from HER2-null to HER2-ultralow, and 18 (24.0%) tumors were upgraded from HER2-ultralow to HER2-low. Furthermore, two tumors (2.7%) were downgraded from HER2-ultralow to HER2-null. Conclusions: Approximately 40% of cases initially categorized as IHC 0 were reclassified as HER2-ultralow. The substantial inter-institutional variability observed in interpreting low-level HER2 expression highlights the need for standardized training and quality assurance to ensure accurate identification of patients eligible for HER2-targeted antibody–drug conjugates.

Purpose: To evaluate functional and anatomical outcomes, including vessel morphology parameters on swept-source optical coherence tomography angiography (SS-OCTA), in eyes with neovascular age-related macular degeneration (nAMD) switched to brolucizumab. Methods: This retrospective study included 37 eyes with nAMD that were switched from other anti–vascular endothelial growth factor (anti-VEGF) agents to intravitreal brolucizumab. Best-corrected visual acuity (BCVA), injection intervals, central subfield thickness (CST), pigment epithelial detachment (PED), and presence of retinal fluid were compared between baseline and 12 months after switch. SS-OCTA images were analyzed to quantify macular neovascularization (MNV) area, vessel density, fractal dimension (FD), and lacunarity. Results: Switching to brolucizumab significantly extended injection intervals and reduced CST, PED height and retinal fluid, while maintaining BCVA at 12 months. Quantitative OCTA analysis showed reductions in MNV area and FD following the switch. When compared with the preceding 12 months of other anti-VEGF therapy, FD still showed a significant reduction after brolucizumab treatment (p = 0.019). Intraocular inflammation occurred in one eye and resolved with topical corticosteroids. Conclusions Intravitreal brolucizumab demonstrated favorable anatomical improvements and maintained visual outcomes over 12 months. Quantitative OCTA biomarkers, particularly FD, may serve as imaging indicators of disease activity and treatment response in eyes with nAMD undergoing a therapy switch.

Purpose: This study aimed to quantitatively evaluate longitudinal changes in drusen area and volume over 36 months in South Korean patients and to identify the factors associated with these changes and the development of advanced age-related macular degeneration (AMD). Methods: In this retrospective study, 38 eyes from 38 patients diagnosed with drusen were analyzed. The drusen area and volume were measured using spectral-domain optical coherence tomography (SD-OCT; Cirrus 5000, Carl Zeiss Meditec) with an automated retinal pigment epithelium elevation map algorithm. To minimize bias from variable follow-up intervals, an annualized classification framework was adopted. Based on percentage change in drusen area within the 5-mm circle, eyes were categorized as progressed (increase >20%), stable (change within ±20%), or regressing (decrease >20%). Results: Both drusen area and volume increased significantly up to 24 months (area, p = 0.003; volume, p = 0.028) and then showed a modest decline at 36 months, remaining above baseline levels. No significant difference in the proportions of progressed, stable, or regressing eyes was observed across 12-month intervals or compared with baseline (all p > 0.05). A larger baseline 5-mm drusen area was significantly associated with the development of advanced AMD (adjusted odds ratio, 2.818; 95% confidence interval, 1.022–7.767; p = 0.045). Eyes that exhibited at least one episode of drusen regression showed a higher incidence of advanced AMD (36.8% vs. 5.3%, p = 0.042). Conclusions Drusen in South Korean patients demonstrated dynamic morphological remodeling over time. Drusen regression was not a benign phenomenon but rather a potential high-risk marker for progression to advanced AMD. These findings highlight the importance of population-specific, quantitative SD-OCT monitoring for early risk stratification in East Asian eyes.

Pediatric kidney disease has a relatively lower prevalence than do other pediatric conditions and has a notably different etiology from kidney diseases observed in adults. Furthermore, the pediatric population is unique in that they experience ongoing growth and development, distinguishing them from adult patients. Consequently, pediatric patients with kidney disease require more specialized and meticulous nutritional management than do adults. To address this need and promote optimal dietary practices for pediatric patients with kidney disease, pediatric nephrologists from the Korean Society of Pediatric Nephrology and nutritionists from the Korean Society of Clinical Nutrition have collaborated to establish nutritional guidelines specifically tailored to Korean dietary patterns. These guidelines offer detailed, nutrient-specific recommendations covering energy, protein, calcium, phosphorus, and potassium consumption while providing practical, culturally relevant guidance intended to support both pediatric patients and their caregivers.

Objective: We investigated the distribution of AI viruses in fecal samples from wild bird habitats (and nearby poultry-farm areas) surveyed between September and March from 2019 to 2025 and identified associated epidemiological risk factors. Methods: Samples were screened for influenza A (M, H5, H7) genes using real-time reverse transcription polymerase chain reaction (PCR), subjected to virus isolation in embryonated chicken eggs, and subtyped by PCR and sequencing. Host species were identified through DNA barcoding. Relative risks (RRs) with 95% confidence intervals were estimated for province, month, and waterfowl density. Results: Overall prevalence of HPAI and low pathogenic AI (LPAI) virus was 0.10% and 3.21%, respectively. HPAI virus was continuously isolated since 2020–2021, except 2019– 2020, while LPAI prevalence steadily increased (3.01%–4.35%). Twelve hemagglutinin (H1–H12) subtypes were identified in 1,722 isolates, and H3 (16.5%) was the most prevalent, followed by H5 (11.1%) and H7 (5.2%). LPAI H5N3 (55.7%) and H7N7 (75.5%) were the predominant H5 and H7 subtypes, respectively. Detection was higher in western coastal provinces, and higher mallard/spot-billed duck density and sampling in September– December were associated with increased risk. Conclusions and Relevance: Continued surveillance of migratory-bird habitats can provide early warning of HPAIV incursions and support targeted biosecurity measures in high-risk regions and seasons.