Background: Cancer cell line-derived feeder cells enhance natural killer (NK) cell expansion; however, concerns regarding viable residual feeder cells in the final product limit their use. Evidence supporting the safety of NK-sensitive K562-based feeders, even when irradiated, is scarce. We optimized an NK cell expansion protocol using genetically engineered K562-mbIL-18/-21 (GE-K562) feeder cells and clinical-grade media and confirmed the absence of residual feeder cells. Methods: NK cell expansion efficiency was compared between feeder-free and feederbased systems using CTS NK-Xpander Medium. To achieve optimal NK expansion, various peripheral blood mononuclear cell (PBMC)-to-feeder ratios and re-stimulation frequencies were tested over 21 days. Flow cytometry and BCR::ABL1 quantitative reverse transcription PCR (RT-qPCR) were used to confirm the absence of feeder cells in the final NK cell product. Results: Feeder-based systems showed superior NK cell fold expansion compared with that of feeder-free systems. Among feeder-based conditions, NK cells expanded 5,224-fold at a 2:1 PBMC-to-feeder ratio after 3 weeks, relative to 1,450-fold at a 6:1 ratio (P < 0.05).Re-stimulation on days 7 and 14 further increased expansion up to 261,457-fold. Irradiated feeder cells showed no proliferation and were eliminated within 3–6 days. On day 21, flow cytometry and BCR::ABL1 RT-qPCR results confirmed the absence of residual feeder cells. Conclusions Our optimized NK cell expansion protocol using irradiated GE-K562 feeder cells and clinical-grade media offers a safe and scalable approach to generating large numbers of NK cells, supporting its potential use in clinical immunotherapy applications.

Purpose: Forming a patient safety culture is the first step in addressing patient safety issues. This study therefore examines the patient safety culture among healthcare professionals in South Korea. It also identifies the factors influencing patient safety culture and related activities. Methods: Among the survey studies conducted in South Korea, we reviewed those that measured patient safety culture using the Korean version of the Hospital Survey on Patient Safety Culture 1.0. We identified the level of patient safety culture, the relationship between patient safety culture and patient safety activities, and the factors affecting patient safety culture. Results: A total of 640 studies were identified through searches of seven domestic and international databases, with 58 included in the analysis. Studies targeting nurses accounted for 96.6%. The general characteristics of patient safety culture included length of service, age, working hours, department of work, hospital size, conflict occurrence, unreported incidents, and subjective safety management evaluations. A statistically significant correlation between patient safety culture and patient safety activities was confirmed in 84.5% of studies. Patient safety culture was the most frequently reported factor influencing patient safety activities. Conclusion Strategies to enhance patient safety culture can promote patient safety activities in South Korean healthcare institutions. Considering organizational and organizational members characteristics when devising these strategies can enhance their effectiveness.

Purpose: Forming a patient safety culture is the first step in addressing patient safety issues. This study therefore examines the patient safety culture among healthcare professionals in South Korea. It also identifies the factors influencing patient safety culture and related activities. Methods: Among the survey studies conducted in South Korea, we reviewed those that measured patient safety culture using the Korean version of the Hospital Survey on Patient Safety Culture 1.0. We identified the level of patient safety culture, the relationship between patient safety culture and patient safety activities, and the factors affecting patient safety culture. Results: A total of 640 studies were identified through searches of seven domestic and international databases, with 58 included in the analysis. Studies targeting nurses accounted for 96.6%. The general characteristics of patient safety culture included length of service, age, working hours, department of work, hospital size, conflict occurrence, unreported incidents, and subjective safety management evaluations. A statistically significant correlation between patient safety culture and patient safety activities was confirmed in 84.5% of studies. Patient safety culture was the most frequently reported factor influencing patient safety activities. Conclusion Strategies to enhance patient safety culture can promote patient safety activities in South Korean healthcare institutions. Considering organizational and organizational members characteristics when devising these strategies can enhance their effectiveness.

Purpose: Forming a patient safety culture is the first step in addressing patient safety issues. This study therefore examines the patient safety culture among healthcare professionals in South Korea. It also identifies the factors influencing patient safety culture and related activities. Methods: Among the survey studies conducted in South Korea, we reviewed those that measured patient safety culture using the Korean version of the Hospital Survey on Patient Safety Culture 1.0. We identified the level of patient safety culture, the relationship between patient safety culture and patient safety activities, and the factors affecting patient safety culture. Results: A total of 640 studies were identified through searches of seven domestic and international databases, with 58 included in the analysis. Studies targeting nurses accounted for 96.6%. The general characteristics of patient safety culture included length of service, age, working hours, department of work, hospital size, conflict occurrence, unreported incidents, and subjective safety management evaluations. A statistically significant correlation between patient safety culture and patient safety activities was confirmed in 84.5% of studies. Patient safety culture was the most frequently reported factor influencing patient safety activities. Conclusion Strategies to enhance patient safety culture can promote patient safety activities in South Korean healthcare institutions. Considering organizational and organizational members characteristics when devising these strategies can enhance their effectiveness.

Background/Aims: The purpose of the current study was to examine the anti-inflammatory effects of CKD-506, a novel histone deacetylase 6 inhibitor, on human peripheral blood mononuclear cells (PBMCs) and CD4+ T cells and to explore the relationship between CKD-506 and gut epithelial barrier function. Methods: Lipopolysaccharide-stimulated human PBMCs from inflammatory bowel disease (IBD) patients were treated with CKD-506, and tumor necrosis factor (TNF)-α expression was measured using an enzyme-linked immunosorbent assay. The proliferation of CD4+ T cells from IBD patients was evaluated using flow cytometric analysis. The effects of CKD-506 on gut barrier function in a cell line and colon organoids, based on examinations of mRNA production, goblet cell differentiation, and E-cadherin recovery, were investigated using quantitative reverse transcription polymerase chain reaction, immunofluorescence, and a fluorescein isothiocyanatedextran permeability assay. Results: Secretion of TNF-α, a pivotal pro-inflammatory mediator in IBD, by lipopolysaccharidetriggered PBMCs was markedly decreased by CKD-506 treatment in a dose-dependent manner and to a greater extent than by tofacitinib or tubastatin A treatment. E-cadherin mRNA expression and goblet cell differentiation increased significantly and dose-dependently in HT-29 cells in response to CKD-506, and inhibition of E-cadherin loss after TNF-α stimulation was significantly reduced both in HT-29 cells and gut organoids. Caco-2 cells treated with CKD-506 showed a significant reduction in barrier permeability in a dose-dependent manner. Conclusions The present study demonstrated that CKD-506 has anti-inflammatory effects on PBMCs and CD4 T cells and improves gut barrier function, suggesting its potential as a smallmolecule therapeutic option for IBD.

Objectives: The household secondary attack rate (SAR) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important indicator for community transmission. This study aimed to characterize transmission by comparing household SARs and identifying risk factors during the periods of Delta and Omicron variant predominance in Republic of Korea. Methods: We defined the period of Delta variant predominance (Delta period) as July 25, 2021 to January 15, 2022, and the period of Omicron variant predominance (Omicron period) as February 7 to September 3, 2022. The number of index cases included was 214,229 for the Delta period and 5,521,393 for the Omicron period. To identify the household SARs and risk factors for each period, logistic regression was performed to determine the adjusted odds ratio (aOR). Results: The SAR was 35.2% for the Delta period and 43.1% for the Omicron period. The aOR of infection was higher in 2 groups, those aged 0 to 18 years and ≥75 years, compared to those aged 19 to 49 years. Unvaccinated individuals (vs. vaccinated individuals) and individuals experiencing initial infection (vs. individuals experiencing a second or third infection) had an increased risk of infection with SARS-CoV-2. Conclusion: This study analyzed the household SARs and risk factors. We hope that the results can help develop age-specific immunization plans and responses to reduce the SAR in preparation for emerging infectious diseases or potential new variants of SARS-CoV-2.