BACKGROUND/OBJECTIVES: This study aimed to use plasma metabolites to identify clusters of breast cancer survivors and to compare their dietary characteristics and health-related factors across the clusters using unsupervised machine learning. SUBJECTS/METHODS: A total of 419 breast cancer survivors were included in this crosssectional study. We considered 30 plasma metabolites, quantified by high-throughput nuclear magnetic resonance metabolomics. Clusters were obtained based on metabolites using 4 different unsupervised clustering methods: k-means (KM), partitioning around medoids (PAM), self-organizing maps (SOM), and hierarchical agglomerative clustering (HAC). The t-test, χ2 test, and Fisher’s exact test were used to compare sociodemographic, lifestyle, clinical, and dietary characteristics across the clusters. P-values were adjusted through a false discovery rate (FDR). RESULTS: Two clusters were identified using the 4 methods. Participants in cluster 2 had lower concentrations of apolipoprotein A1 and large high-density lipoprotein (HDL) particles and smaller HDL particle sizes, but higher concentrations of chylomicrons and extremely large very-low-density-lipoprotein (VLDL) particles and glycoprotein acetyls, a higher ratio of monounsaturated fatty acids to total fatty acids, and larger VLDL particle sizes compared with cluster 1. Body mass index was significantly higher in cluster 2 compared with cluster 1 (FDR adjusted-PKM < 0.001; PPAM = 0.001; PSOM < 0.001; and PHAC = 0.043). CONCLUSION The breast cancer survivors clustered on the basis of plasma metabolites had distinct characteristics. Further prospective studies are needed to investigate the associations between metabolites, obesity, dietary factors, and breast cancer prognosis.

Pulmonary hypertension is more common in preterm infants compared to term infants, and the incidence increases as gestational age decreases. In preterm infants, pulmonary hypertension is a risk factor that increases mortality. Inhaled nitric oxide (iNO) is an approved treatment for pulmonary hypertension in preterm infants in Korea. Since January 2021, iNO has been used for hypoxic respira tory failure associated with early acute persistent pulmonary hypertension of the newborn (PPHN) in preterm infants. Although studies suggest that iNO improves oxygenation and reduces mortality in preterm infants with pulmonary hypertension, there are concerns about its effectiveness and potential adverse effects. In addition, there are several challenges in administering iNO therapy to pre­term infants in Korea that need to be addressed. The current therapeutic indications in Korea allow iNO therapy to be administered only if treatment is started within 14 days of life, so it cannot be used for late pulmonary hypertension. Additionally, iNO therapy requires meeting the criteria for hypoxic respiratory failure, which includes calculating the oxygenation index (OI) using PaO 2 values obtained from arterial blood gas analysis (ABGA). To evaluate treatment response, PaO 2 values from ABGA are also necessary. However, invasive arterial blood sampling is a particularly challenging procedure in preterm infants. Therefore, alternative criteria beyond OI are needed. Furthermore, echocardiographic findings are essential to determine the therapeutic indication for PPHN in iNO therapy. However, not all neonatal intensive care units have consistent access to echocardiography. These issues must be addressed and resolved through further research and evidence.

BACKGROUND/OBJECTIVES: This study aimed to use plasma metabolites to identify clusters of breast cancer survivors and to compare their dietary characteristics and health-related factors across the clusters using unsupervised machine learning. SUBJECTS/METHODS: A total of 419 breast cancer survivors were included in this crosssectional study. We considered 30 plasma metabolites, quantified by high-throughput nuclear magnetic resonance metabolomics. Clusters were obtained based on metabolites using 4 different unsupervised clustering methods: k-means (KM), partitioning around medoids (PAM), self-organizing maps (SOM), and hierarchical agglomerative clustering (HAC). The t-test, χ2 test, and Fisher’s exact test were used to compare sociodemographic, lifestyle, clinical, and dietary characteristics across the clusters. P-values were adjusted through a false discovery rate (FDR). RESULTS: Two clusters were identified using the 4 methods. Participants in cluster 2 had lower concentrations of apolipoprotein A1 and large high-density lipoprotein (HDL) particles and smaller HDL particle sizes, but higher concentrations of chylomicrons and extremely large very-low-density-lipoprotein (VLDL) particles and glycoprotein acetyls, a higher ratio of monounsaturated fatty acids to total fatty acids, and larger VLDL particle sizes compared with cluster 1. Body mass index was significantly higher in cluster 2 compared with cluster 1 (FDR adjusted-PKM < 0.001; PPAM = 0.001; PSOM < 0.001; and PHAC = 0.043). CONCLUSION The breast cancer survivors clustered on the basis of plasma metabolites had distinct characteristics. Further prospective studies are needed to investigate the associations between metabolites, obesity, dietary factors, and breast cancer prognosis.

Pulmonary hypertension is more common in preterm infants compared to term infants, and the incidence increases as gestational age decreases. In preterm infants, pulmonary hypertension is a risk factor that increases mortality. Inhaled nitric oxide (iNO) is an approved treatment for pulmonary hypertension in preterm infants in Korea. Since January 2021, iNO has been used for hypoxic respira tory failure associated with early acute persistent pulmonary hypertension of the newborn (PPHN) in preterm infants. Although studies suggest that iNO improves oxygenation and reduces mortality in preterm infants with pulmonary hypertension, there are concerns about its effectiveness and potential adverse effects. In addition, there are several challenges in administering iNO therapy to pre­term infants in Korea that need to be addressed. The current therapeutic indications in Korea allow iNO therapy to be administered only if treatment is started within 14 days of life, so it cannot be used for late pulmonary hypertension. Additionally, iNO therapy requires meeting the criteria for hypoxic respiratory failure, which includes calculating the oxygenation index (OI) using PaO 2 values obtained from arterial blood gas analysis (ABGA). To evaluate treatment response, PaO 2 values from ABGA are also necessary. However, invasive arterial blood sampling is a particularly challenging procedure in preterm infants. Therefore, alternative criteria beyond OI are needed. Furthermore, echocardiographic findings are essential to determine the therapeutic indication for PPHN in iNO therapy. However, not all neonatal intensive care units have consistent access to echocardiography. These issues must be addressed and resolved through further research and evidence.

This study aimed to identify the factors affecting dry eye syndrome and quality of life (QoL) among college students. Methods: This cross-sectional study administered a descriptive survey to 184 college students across Korea. Data collection was conducted from August 27 to 28, 2024, using an online survey platform (Google Forms). The self-reported survey comprised the Health-Related Quality of Life Instrument with 8 Items scale, the Dry Eye Questionnaire 5, and the Ocular Surface Disease Index. Data analysis was performed using SPSS version 27.0. Results: The participants had a mean age of 21.37 (standard deviation 1.96) years. Regression analysis identified sleep satisfaction, vision-related functions, and dry eye symptoms as statistically significant predictors of QoL, accounting for 18.4% of the variance (F = 14.71, p < .001). Dry eye symptoms were significantly influenced by the use of artificial tears, vision-related functions, and environmental factors, which accounted for 41.3% of the variance (F = 43.93, p < .001). Additionally, significant determinants of ocular surface disease included the use of vision correction tools, the presence of ophthalmic diseases, sleep satisfaction, and dry eye symptoms. These factors explained 45.7% of the variance, confirming the model's robustness (F = 31.84, p < .001). Conclusion: It is necessary to identify strategies to alleviate dry eye syndrome in college students and develop comprehensive prevention and management programs to improve their QoL.

Myelodysplastic syndrome (MDS), a myeloid tumor derived from the malignant clones of hematopoietic stem cells, has an annually increasing incidence. The contemporary research direction has shifted to analyzing the synergistic effect of immune surveillance collapse and abnormal bone marrow microenvironment in the pathological process of MDS. Against this backdrop, the immune checkpoint molecule TIM3 has emerged as a key target because of its persistently high expression on the surface of important immune cells such as T and NK cells. The abnormal activation of the TIM3 pathway is the mechanism by which solid tumors and hematological malignancies achieve immune escape and is a key hub in the formation of immune exhaustion phenotypes. This work integrates the original discoveries of our team with the latest international progress, systematically demonstrating the bidirectional regulatory network of TIM3 between the malignant clone proliferation of MDS and the immunosuppressive microenvironment. Integrating the evidence from emerging clinical trials allows us to consider the clinical significance of TIM3-targeted blocking for MDS, providing a transformative path to overcome the resistance of traditional treatments and marking a new chapter in the active immune reconstitution of MDS treatment.

Background/Aims: Portal vein thrombosis (PVT) frequently occurs in patients with inflammatory bowel disease (IBD), particularly when influenced by factors such as abdominal infections, IBD flare-ups, or surgical procedures. The implications of PVT range from immediate issues such as intestinal ischemia to long-term concerns including portal hypertension and its complications. However, there is a notable gap in comprehensive studies on PVT in IBD, especially with the increasing incidence of IBD in Asia. This research aimed to evaluate the clinical features and outcomes of PVT in patients with IBD at a leading hospital in South Korea. Methods: This retrospective analysis reviewed adult patients diagnosed with both IBD and PVT from 1989 to 2021 at a renowned South Korean medical center. The study focused on patient characteristics, specifics of PVT, administered treatments, and outcomes, all confirmed through enhanced CT scans. Results: A total of 78 patients met the study’s criteria. Notably, only 20.5% (16/78) were treated with oral anticoagulants; however, a vast majority (96.2%; 75/78) achieved complete radiographic resolution (CRR). When comparing patients receiving anticoagulants to those who did not, a significant preference for anticoagulant use was observed in cases where the main portal vein was affected, as opposed to just the left or right veins (p = 0.006). However, multivariable analysis indicated that neither anticoagulant use nor previous surgeries significantly impacted CRR. Conclusions Patients with IBD and PVT generally had favorable outcomes, regardless of anticoagulant use.

Purpose: Central venous catheter (CVC) insertion is a fundamental skill required for trainees to become proficient. Simulation-based training (SBT) has been shown to improve trainees’ CVC insertion performance effectively. However, implementing a CVC curriculum requires substantial costs and resources. Currently, there is a lack of validated CVC curricula that institutions can adopt as frameworks. This study aimed to evaluate the effectiveness of our institution’s CVC simulation curriculum in improving residents’ confidence and comfort with CVC insertion and management. Materials and Methods: First-year residents (n=118) participated in SBT between 2017 and 2023. Among them, 57 (48%) participants completed surveys before training and 6 months post-training to assess changes in comfort levels across various aspects of CVC insertion. Survey responses were analyzed to evaluate the overall changes in comfort by year and items. Results: Overall comfort increased from 42.1% before training to 81.3% after training (P<0.01), with notable improvements in nonprocedural aspects. Comfort with performing the unsupervised procedure increased by 16.7% (P<0.05) but remained low post-training (29.6%). Conclusion These findings suggest that the curriculum effectively enhances residents’ comfort, particularly in nonprocedural aspects, but only partially prepares them for unsupervised CVC insertions. This indicates a gap in procedural skill acquisition despite the overall positive trends. Implementing a similar CVC curriculum may help institutions reduce CVC insertion-associated complications.

Background: This study aimed to analyze the medical expenses covered by the Korean National Health Insurance Service (KNHIS) according to body mass index (BMI) in Korean adults. Methods: We included 1,170,464 adults (623,498 men and 546,966 women) aged ≥19 years from the KNHISNational Sample Cohort database (2016 to 2019) after excluding individuals with cancer. Average annual medical expenses per person and average annual medical expenses (Korean won [KRW], 1 United States dollar=1,292 KRW) by BMI classification were assessed according to age and sex. Medical expenses comprised those for medication and combined outpatient department (OPD) and hospitalization services. Means and 95% confidence intervals were analyzed using a two-part model. Results: Average annual medical expenses increased in higher BMI quintile groups (P for trend <0.001). Average annual medical expenses per person increased significantly as BMI increased in women but not in men. Average annual medical expenses were highest in the highest quintile of BMI among women and in all age groups.While BMI showed a U-shape association with medical expenses for OPD and hospitalization in young individuals, medical expenses for medication in all age groups and those for OPD and hospitalization in middle-aged individuals increased sharply in the highest BMI quintile. Conclusion All types of average annual medical expenses increased in higher BMI groups in Korean adults, particularly in women. Individuals with the highest BMI quintile incurred the greatest medical expenses among women and across all age groups. Strategies for preventing and managing obesity are warranted to reduce the burden of obesity-related medical expenses.