Background: The aim of this study is to investigate the specific pathway involved in human leukocyte antigen (HLA) sensitization using single-cell RNA-sequencing analysis and an allo-sensitized mouse model developed with an HLA.A2 transgenic mouse. Methods: For sensitization, wild-type C57BL/6 mouse received two skin grafts from C57BL/6-Tg(HLA-A2.1)1Enge/J mouse (allogeneic mouse, ALLO). For syngeneic control (SYN), skin grafts were transferred from C57BL/6 to C57BL/6. We performed single-cell RNA-sequencing analysis on splenocytes isolated from ALLO and SYN and compared the gene expression between them. Results: We generated 9,190 and 8,890 single-cell transcriptomes from ALLO and SYN, respectively. Five major cell types (B cells, T cells, natural killer cells, macrophages, and neutrophils) and their transcriptome data were annotated according to the representative differentially expressed genes of each cell cluster. The percentage of B cells was higher in ALLO than it was in SYN. Kyoto Encyclopedia of Genes and Genomes enrichment analyses indicated that the highly expressed genes in the B cells from ALLO were mainly associated with antigen processing and presentation pathways, allograft rejection, and the Th17 cell differentiation pathway. Upregulated genes in the T cells of ALLO were involved in the interleukin (IL)-17 signaling pathway. The ratio of Th17 cluster and Treg cluster was increased in the ALLO. On flow cytometry, the percentage of Th17 (IL-17+/CD4+ T) cells was higher and regulatory T cells (FOXP3+/CD4+ T) was lower in the ALLO compared to those in the SYN. Conclusion Our results indicate that not only the B cell lineage but also the Th17 cells and their cytokine (IL-17) are involved in the sensitization to HLA.

Objective: Primary frozen shoulder causes significant pain and progressively restricts shoulder movements. Diagnosis is made clinically based on patient history and physical examination. Management is mainly non-invasive owing to its self-limiting clinical course. However, clinical practice guidelines for frozen shoulder have not yet been developed in Korea. The developed guidelines aim to provide evidence-based recommendations for the diagnosis and treatment of frozen shoulder. Methods: A guideline development committee reviewed the literature from four databases (PubMed, Embase, Cochrane Library, and KMbase). Using the Population, Intervention, Comparator, and Outcome (PICO) framework, the committee formulated two backgrounds and 16 key questions to address common clinical concerns. Recommendations were made using the Grading of Recommendations, Assessment, Development, and Evaluation framework. Results: Diabetes, thyroid disease, and dyslipidemia significantly increase the risk of developing a frozen shoulder. Although frozen shoulder is often self-limiting, some patients may experience long-term functional disabilities. Ultrasound and magnetic resonance imaging should be used as adjunctive tools alongside clinical diagnosis, and rather than as independent diagnostic methods. Noninvasive approaches, such as medications, physical modalities, exercises, electrical stimulation, and manual therapy, may reduce pain and improve shoulder function. Other noninvasive interventions have limited evidence, and their application should be based on clinical judgment. Intra-articular steroid injections are recommended for treatment, and physiotherapy or hydrodilation with steroid injections can also be beneficial. Conclusion These guidelines provide evidence-based recommendations for diagnosing and treating primary frozen shoulder.

Purpose: To analyze adenoma detection rate (ADR) and related quality indicators of colonoscopy among trainees and make recommendations for appropriate colonoscopy training. Methods: ADR and related indicators of colonoscopies performed by 3 trainees and 5 colonoscopy experts between March and November 2022 were analyzed. These indicators were analyzed in both the entire patients and the screening/surveillance group. In addition, the training period of the 3 trainees was divided into 3 sections, and the changes in these indicators were examined. Results: The mean ADR of the 3 trainees was 50.6%. In the screening/surveillance group, the mean ADR of the 3 trainees was 51.8%, showing no significant difference from the experts' ADR (53.4%). When the training period was divided into 3 sections and analyzed in the screening/surveillance group, the mean ADR of the trainees gradually increased to 49.4%, 52.6%, and 53.6%, respectively; however, the difference was insignificant. Analyzing each trainee’s ADR, there was a significant difference among the 3 trainees (58.5% vs. 44.7% vs. 50.2%, P=0.008). However, in the third section of the training period, the 3 trainees’ ADRs were 53.0%, 49.2%, and 57.3%, respectively, showing no significant difference (P=0.606). Conclusion In the early stages of training, the ADR was higher than recommended; however, there were variances in ADR between individuals. As the training period passed, the ADR became similar at the expert level, whereas the difference in ADR between trainees decreased. Therefore, efforts to increase ADR should be made actively from the beginning of training and continued during the training period.

Purpose: To analyze adenoma detection rate (ADR) and related quality indicators of colonoscopy among trainees and make recommendations for appropriate colonoscopy training. Methods: ADR and related indicators of colonoscopies performed by 3 trainees and 5 colonoscopy experts between March and November 2022 were analyzed. These indicators were analyzed in both the entire patients and the screening/surveillance group. In addition, the training period of the 3 trainees was divided into 3 sections, and the changes in these indicators were examined. Results: The mean ADR of the 3 trainees was 50.6%. In the screening/surveillance group, the mean ADR of the 3 trainees was 51.8%, showing no significant difference from the experts' ADR (53.4%). When the training period was divided into 3 sections and analyzed in the screening/surveillance group, the mean ADR of the trainees gradually increased to 49.4%, 52.6%, and 53.6%, respectively; however, the difference was insignificant. Analyzing each trainee’s ADR, there was a significant difference among the 3 trainees (58.5% vs. 44.7% vs. 50.2%, P=0.008). However, in the third section of the training period, the 3 trainees’ ADRs were 53.0%, 49.2%, and 57.3%, respectively, showing no significant difference (P=0.606). Conclusion In the early stages of training, the ADR was higher than recommended; however, there were variances in ADR between individuals. As the training period passed, the ADR became similar at the expert level, whereas the difference in ADR between trainees decreased. Therefore, efforts to increase ADR should be made actively from the beginning of training and continued during the training period.

Purpose: To analyze adenoma detection rate (ADR) and related quality indicators of colonoscopy among trainees and make recommendations for appropriate colonoscopy training. Methods: ADR and related indicators of colonoscopies performed by 3 trainees and 5 colonoscopy experts between March and November 2022 were analyzed. These indicators were analyzed in both the entire patients and the screening/surveillance group. In addition, the training period of the 3 trainees was divided into 3 sections, and the changes in these indicators were examined. Results: The mean ADR of the 3 trainees was 50.6%. In the screening/surveillance group, the mean ADR of the 3 trainees was 51.8%, showing no significant difference from the experts' ADR (53.4%). When the training period was divided into 3 sections and analyzed in the screening/surveillance group, the mean ADR of the trainees gradually increased to 49.4%, 52.6%, and 53.6%, respectively; however, the difference was insignificant. Analyzing each trainee’s ADR, there was a significant difference among the 3 trainees (58.5% vs. 44.7% vs. 50.2%, P=0.008). However, in the third section of the training period, the 3 trainees’ ADRs were 53.0%, 49.2%, and 57.3%, respectively, showing no significant difference (P=0.606). Conclusion In the early stages of training, the ADR was higher than recommended; however, there were variances in ADR between individuals. As the training period passed, the ADR became similar at the expert level, whereas the difference in ADR between trainees decreased. Therefore, efforts to increase ADR should be made actively from the beginning of training and continued during the training period.

Purpose: To analyze adenoma detection rate (ADR) and related quality indicators of colonoscopy among trainees and make recommendations for appropriate colonoscopy training. Methods: ADR and related indicators of colonoscopies performed by 3 trainees and 5 colonoscopy experts between March and November 2022 were analyzed. These indicators were analyzed in both the entire patients and the screening/surveillance group. In addition, the training period of the 3 trainees was divided into 3 sections, and the changes in these indicators were examined. Results: The mean ADR of the 3 trainees was 50.6%. In the screening/surveillance group, the mean ADR of the 3 trainees was 51.8%, showing no significant difference from the experts' ADR (53.4%). When the training period was divided into 3 sections and analyzed in the screening/surveillance group, the mean ADR of the trainees gradually increased to 49.4%, 52.6%, and 53.6%, respectively; however, the difference was insignificant. Analyzing each trainee’s ADR, there was a significant difference among the 3 trainees (58.5% vs. 44.7% vs. 50.2%, P=0.008). However, in the third section of the training period, the 3 trainees’ ADRs were 53.0%, 49.2%, and 57.3%, respectively, showing no significant difference (P=0.606). Conclusion In the early stages of training, the ADR was higher than recommended; however, there were variances in ADR between individuals. As the training period passed, the ADR became similar at the expert level, whereas the difference in ADR between trainees decreased. Therefore, efforts to increase ADR should be made actively from the beginning of training and continued during the training period.

Purpose: To analyze adenoma detection rate (ADR) and related quality indicators of colonoscopy among trainees and make recommendations for appropriate colonoscopy training. Methods: ADR and related indicators of colonoscopies performed by 3 trainees and 5 colonoscopy experts between March and November 2022 were analyzed. These indicators were analyzed in both the entire patients and the screening/surveillance group. In addition, the training period of the 3 trainees was divided into 3 sections, and the changes in these indicators were examined. Results: The mean ADR of the 3 trainees was 50.6%. In the screening/surveillance group, the mean ADR of the 3 trainees was 51.8%, showing no significant difference from the experts' ADR (53.4%). When the training period was divided into 3 sections and analyzed in the screening/surveillance group, the mean ADR of the trainees gradually increased to 49.4%, 52.6%, and 53.6%, respectively; however, the difference was insignificant. Analyzing each trainee’s ADR, there was a significant difference among the 3 trainees (58.5% vs. 44.7% vs. 50.2%, P=0.008). However, in the third section of the training period, the 3 trainees’ ADRs were 53.0%, 49.2%, and 57.3%, respectively, showing no significant difference (P=0.606). Conclusion In the early stages of training, the ADR was higher than recommended; however, there were variances in ADR between individuals. As the training period passed, the ADR became similar at the expert level, whereas the difference in ADR between trainees decreased. Therefore, efforts to increase ADR should be made actively from the beginning of training and continued during the training period.