1.Poor Prognosis of Pneumococcal Co-Infection in Hospitalized Patients with COVID-19: A Propensity Score-Matched Analysis
Soyoon HWANG ; Eunkyung NAM ; Shin-Woo KIM ; Hyun-Ha CHANG ; Yoonjung KIM ; Sohyun BAE ; Nan Young LEE ; Yu Kyung KIM ; Ji Sun KIM ; Han Wook PARK ; Joon Gyu BAE ; Juhwan JEONG ; Ki Tae KWON
Infection and Chemotherapy 2025;57(1):172-178
The impact of Streptococcus pneumoniae coinfection on coronavirus disease 2019 (COVID-19) prognosis remains uncertain. We conducted a retrospective analysis of patients hospitalized with COVID-19 who underwent a pneumococcal urinary antigen (PUA) test to assess its clinical utility. Results showed that PUA-positive patients required more oxygen support, high-flow nasal cannula, and dexamethasone compared to PUA-negative patients.Furthermore, the significantly higher incidence of a National Early Warning Score ≥5 in the PUA-positive group (P<0.001) suggests that a positive PUA test is associated with a severe disease course. However, no significant difference in mortality was observed between the two groups, and antibiotics were used in almost all patients (96.2%). While the PUA test may help guide antibiotic use in COVID-19 patients, its interpretation should be approached with caution.
2.Development of a Machine LearningPowered Optimized Lung Allocation System for Maximum Benefits in Lung Transplantation: A Korean National Data
Mihyang HA ; Woo Hyun CHO ; Min Wook SO ; Daesup LEE ; Yun Hak KIM ; Hye Ju YEO
Journal of Korean Medical Science 2025;40(7):e18-
Background:
An ideal lung allocation system should reduce waiting list deaths, improve transplant survival, and ensure equitable organ allocation. This study aimed to develop a novel lung allocation score (LAS) system, the MaxBenefit LAS, to maximize transplant benefits.
Methods:
This study retrospectively analyzed data from the Korean Network for Organ Sharing database, including 1,599 lung transplant candidates between September 2009 and December 2020. We developed the MaxBenefit LAS, combining a waitlist mortality model and a post-transplant survival model using elastic-net Cox regression, was assessed using area under the curve (AUC) values and Uno’s C-index. Its performance was compared to the US LAS in an independent cohort.
Results:
The waitlist mortality model showed strong predictive performance with AUC values of 0.834 and 0.818 in the training and validation cohorts, respectively. The post-transplant survival model also demonstrated good predictive ability (AUC: 0.708 and 0.685). The MaxBenefit LAS effectively stratified patients by risk, with higher scores correlating with increased waitlist mortality and decreased post-transplant mortality. The MaxBenefit LAS outperformed the conventional LAS in predicting waitlist death and identifying candidates with higher transplant benefits.
Conclusion
The MaxBenefit LAS offers a promising approach to optimizing lung allocation by balancing the urgency of candidates with their likelihood of survival post-transplant. This novel system has the potential to improve outcomes for lung transplant recipients and reduce waitlist mortality, providing a more equitable allocation of donor lungs.
3.Development of a Machine LearningPowered Optimized Lung Allocation System for Maximum Benefits in Lung Transplantation: A Korean National Data
Mihyang HA ; Woo Hyun CHO ; Min Wook SO ; Daesup LEE ; Yun Hak KIM ; Hye Ju YEO
Journal of Korean Medical Science 2025;40(7):e18-
Background:
An ideal lung allocation system should reduce waiting list deaths, improve transplant survival, and ensure equitable organ allocation. This study aimed to develop a novel lung allocation score (LAS) system, the MaxBenefit LAS, to maximize transplant benefits.
Methods:
This study retrospectively analyzed data from the Korean Network for Organ Sharing database, including 1,599 lung transplant candidates between September 2009 and December 2020. We developed the MaxBenefit LAS, combining a waitlist mortality model and a post-transplant survival model using elastic-net Cox regression, was assessed using area under the curve (AUC) values and Uno’s C-index. Its performance was compared to the US LAS in an independent cohort.
Results:
The waitlist mortality model showed strong predictive performance with AUC values of 0.834 and 0.818 in the training and validation cohorts, respectively. The post-transplant survival model also demonstrated good predictive ability (AUC: 0.708 and 0.685). The MaxBenefit LAS effectively stratified patients by risk, with higher scores correlating with increased waitlist mortality and decreased post-transplant mortality. The MaxBenefit LAS outperformed the conventional LAS in predicting waitlist death and identifying candidates with higher transplant benefits.
Conclusion
The MaxBenefit LAS offers a promising approach to optimizing lung allocation by balancing the urgency of candidates with their likelihood of survival post-transplant. This novel system has the potential to improve outcomes for lung transplant recipients and reduce waitlist mortality, providing a more equitable allocation of donor lungs.
4.PDK4 expression and tumor aggressiveness in prostate cancer
Eun Hye LEE ; Yun-Sok HA ; Bo Hyun YOON ; Minji JEON ; Dong Jin PARK ; Jiyeon KIM ; Jun-Koo KANG ; Jae-Wook CHUNG ; Bum Soo KIM ; Seock Hwan CHOI ; Hyun Tae KIM ; Tae-Hwan KIM ; Eun Sang YOO ; Tae Gyun KWON
Investigative and Clinical Urology 2025;66(3):227-235
Purpose:
Prostate cancer ranks as the second most common cancer in men globally, representing a significant cause of cancer-related mortality. Metastasis, the spread of cancer cells from the primary site to distant organs, remains a major challenge in managing prostate cancer. Pyruvate dehydrogenase kinase 4 (PDK4) is implicated in the regulation of aerobic glycolysis, emerging as a potential player in various cancers. However, its role in prostate cancer remains unclear. This study aims to analyze PDK4 expression in prostate cancer cells and human samples, and to explore the gene's clinical significance.
Materials and Methods:
PDK4 expression was detected in cell lines and human tissue samples. Migration ability was analyzed using Matrigel-coated invasion chambers. Human samples were obtained from the Kyungpook National University Chilgok Hospital.
Results:
PDK4 expression was elevated in prostate cancer cell lines compared to normal prostate cells, with particularly high levels in DU145 and LnCap cell lines. PDK4 knockdown in these cell lines suppressed their invasion ability, indicating a potential role of PDK4 in prostate cancer metastasis. Furthermore, our results revealed alterations in epithelial-mesenchymal transition markers and downstream signaling molecules following PDK4 suppression, suggesting its involvement in the modulation of invasion-related pathways. Furthermore, PDK4 expression was increased in prostate cancer tissues, especially in castration-resistant prostate cancer, compared to normal prostate tissues, with PSA and PDK4 expression showing a significantly positive correlation.
Conclusions
PDK4 expression in prostate cancer is associated with tumor invasion and castration status. Further validation is needed to demonstrate its effectiveness as a therapeutic target.
5.Poor Prognosis of Pneumococcal Co-Infection in Hospitalized Patients with COVID-19: A Propensity Score-Matched Analysis
Soyoon HWANG ; Eunkyung NAM ; Shin-Woo KIM ; Hyun-Ha CHANG ; Yoonjung KIM ; Sohyun BAE ; Nan Young LEE ; Yu Kyung KIM ; Ji Sun KIM ; Han Wook PARK ; Joon Gyu BAE ; Juhwan JEONG ; Ki Tae KWON
Infection and Chemotherapy 2025;57(1):172-178
The impact of Streptococcus pneumoniae coinfection on coronavirus disease 2019 (COVID-19) prognosis remains uncertain. We conducted a retrospective analysis of patients hospitalized with COVID-19 who underwent a pneumococcal urinary antigen (PUA) test to assess its clinical utility. Results showed that PUA-positive patients required more oxygen support, high-flow nasal cannula, and dexamethasone compared to PUA-negative patients.Furthermore, the significantly higher incidence of a National Early Warning Score ≥5 in the PUA-positive group (P<0.001) suggests that a positive PUA test is associated with a severe disease course. However, no significant difference in mortality was observed between the two groups, and antibiotics were used in almost all patients (96.2%). While the PUA test may help guide antibiotic use in COVID-19 patients, its interpretation should be approached with caution.
6.Development of a Machine LearningPowered Optimized Lung Allocation System for Maximum Benefits in Lung Transplantation: A Korean National Data
Mihyang HA ; Woo Hyun CHO ; Min Wook SO ; Daesup LEE ; Yun Hak KIM ; Hye Ju YEO
Journal of Korean Medical Science 2025;40(7):e18-
Background:
An ideal lung allocation system should reduce waiting list deaths, improve transplant survival, and ensure equitable organ allocation. This study aimed to develop a novel lung allocation score (LAS) system, the MaxBenefit LAS, to maximize transplant benefits.
Methods:
This study retrospectively analyzed data from the Korean Network for Organ Sharing database, including 1,599 lung transplant candidates between September 2009 and December 2020. We developed the MaxBenefit LAS, combining a waitlist mortality model and a post-transplant survival model using elastic-net Cox regression, was assessed using area under the curve (AUC) values and Uno’s C-index. Its performance was compared to the US LAS in an independent cohort.
Results:
The waitlist mortality model showed strong predictive performance with AUC values of 0.834 and 0.818 in the training and validation cohorts, respectively. The post-transplant survival model also demonstrated good predictive ability (AUC: 0.708 and 0.685). The MaxBenefit LAS effectively stratified patients by risk, with higher scores correlating with increased waitlist mortality and decreased post-transplant mortality. The MaxBenefit LAS outperformed the conventional LAS in predicting waitlist death and identifying candidates with higher transplant benefits.
Conclusion
The MaxBenefit LAS offers a promising approach to optimizing lung allocation by balancing the urgency of candidates with their likelihood of survival post-transplant. This novel system has the potential to improve outcomes for lung transplant recipients and reduce waitlist mortality, providing a more equitable allocation of donor lungs.
7.Poor Prognosis of Pneumococcal Co-Infection in Hospitalized Patients with COVID-19: A Propensity Score-Matched Analysis
Soyoon HWANG ; Eunkyung NAM ; Shin-Woo KIM ; Hyun-Ha CHANG ; Yoonjung KIM ; Sohyun BAE ; Nan Young LEE ; Yu Kyung KIM ; Ji Sun KIM ; Han Wook PARK ; Joon Gyu BAE ; Juhwan JEONG ; Ki Tae KWON
Infection and Chemotherapy 2025;57(1):172-178
The impact of Streptococcus pneumoniae coinfection on coronavirus disease 2019 (COVID-19) prognosis remains uncertain. We conducted a retrospective analysis of patients hospitalized with COVID-19 who underwent a pneumococcal urinary antigen (PUA) test to assess its clinical utility. Results showed that PUA-positive patients required more oxygen support, high-flow nasal cannula, and dexamethasone compared to PUA-negative patients.Furthermore, the significantly higher incidence of a National Early Warning Score ≥5 in the PUA-positive group (P<0.001) suggests that a positive PUA test is associated with a severe disease course. However, no significant difference in mortality was observed between the two groups, and antibiotics were used in almost all patients (96.2%). While the PUA test may help guide antibiotic use in COVID-19 patients, its interpretation should be approached with caution.
8.Development of a Machine LearningPowered Optimized Lung Allocation System for Maximum Benefits in Lung Transplantation: A Korean National Data
Mihyang HA ; Woo Hyun CHO ; Min Wook SO ; Daesup LEE ; Yun Hak KIM ; Hye Ju YEO
Journal of Korean Medical Science 2025;40(7):e18-
Background:
An ideal lung allocation system should reduce waiting list deaths, improve transplant survival, and ensure equitable organ allocation. This study aimed to develop a novel lung allocation score (LAS) system, the MaxBenefit LAS, to maximize transplant benefits.
Methods:
This study retrospectively analyzed data from the Korean Network for Organ Sharing database, including 1,599 lung transplant candidates between September 2009 and December 2020. We developed the MaxBenefit LAS, combining a waitlist mortality model and a post-transplant survival model using elastic-net Cox regression, was assessed using area under the curve (AUC) values and Uno’s C-index. Its performance was compared to the US LAS in an independent cohort.
Results:
The waitlist mortality model showed strong predictive performance with AUC values of 0.834 and 0.818 in the training and validation cohorts, respectively. The post-transplant survival model also demonstrated good predictive ability (AUC: 0.708 and 0.685). The MaxBenefit LAS effectively stratified patients by risk, with higher scores correlating with increased waitlist mortality and decreased post-transplant mortality. The MaxBenefit LAS outperformed the conventional LAS in predicting waitlist death and identifying candidates with higher transplant benefits.
Conclusion
The MaxBenefit LAS offers a promising approach to optimizing lung allocation by balancing the urgency of candidates with their likelihood of survival post-transplant. This novel system has the potential to improve outcomes for lung transplant recipients and reduce waitlist mortality, providing a more equitable allocation of donor lungs.
9.Effect of Residual Stone Fragments on Patient-Reported Quality of Life after Endoscopic Kidney Stone Surgery
Sang Hee LEE ; Jun-Koo KANG ; Jae-Wook CHUNG ; Yun-Sok HA ; Jun Nyung LEE ; Seock Hwan CHOI ; Hyun Tae KIM ; Tae-Hwan KIM ; Eun Sang YOO ; Tae Gyun KWON ; Bum Soo KIM
Urogenital Tract Infection 2024;19(2):31-39
Purpose:
This study examined the effects of residual fragments (RF) on the patient-reported quality of life (QOL) after kidney stone surgery, such as retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PCNL), using the Korean version of the Wisconsin Stone Quality of Life Questionnaire (K-WISQOL).
Materials and Methods:
The medical records of 156 patients who underwent RIRS or PCNL and completed the preoperative and postoperative K-WISQOL from January 2021 to September 2023 were analyzed retrospectively. The patients were divided into RIRS and PCNL groups by the surgical method. The participants completed the K-WISQOL within four weeks before and after treatment. The patients’ baseline characteristics, surgical outcomes, and K-WISQOL scores were compared according to the presence of RF in each surgical group.
Results:
Of the 156 patients, 95 underwent RIRS, and 61 underwent PCNL. In the RIRS group, the patients’ baseline characteristics and surgical outcomes were similar in the stone-free (SF) and RF subgroups. The changes in all K-WISQOL domain scores and total scores were similar in the two subgroups. In the PCNL group, the RF subgroup had a significantly higher proportion of staghorn stones, a significantly larger mean stone diameter and significantly longer operation time than those of the SF subgroup. But, the changes in all K-WISQOL domain scores and total scores were not significantly different between the two subgroups, as observed in the RIRS group.
Conclusions
This study showed that the presence of RFs after endoscopic kidney surgery did not affect the short-term patient-reported QOL regardless of the surgical methods.
10.Outbreak of Cystoscopy-Related Urinary Tract Infections With Pseudomonas aeruginosa in South Korea, 2022: A Case Series
Beomsoo KIM ; Young-Sin CHOI ; Jun-Koo KANG ; Yun-Sok HA ; Seock Hwan CHOI ; Bum Soo KIM ; Hyun Tae KIM ; Eun Sang YOO ; Tae Gyun KWON ; Jae-Wook CHUNG ; Tae-Hwan KIM
Urogenital Tract Infection 2024;19(3):97-103
Purpose:
This study conducted an epidemiological investigation of Pseudomonas aeruginosa urinary tract infections (UTIs) following cystoscopy at Chilgok Kyungpook National University Hospital.
Materials and Methods:
From May 16 to July 15, 2022, among 353 patients who underwent cystoscopy, 6 patients reported febrile UTIs following cystoscopy. They were admitted to the urology department of the hospital after visiting the Emergency Department. P. aeruginosa was found in the urine cultures of 4 of the 6 hospitalized patients. During the epidemiological investigation, no changes were observed in factors such as the reprocessing procedures for endoscopic equipment. Therefore, microbiological tests were performed using environmental samples derived from the endoscopic equipment and cleaning process.
Results:
P. aeruginosa was identified in a dual-enzymatic detergent (EmPower) used during the endoscope cleaning process. After changing the disinfectant and cleaning process, no further bacterial growth was observed in subsequent microbiological tests.
Conclusions
This study highlights the potential of cystoscopes to serve as reservoirs for bacteria due to inadequate cleaning during the disinfection process. To minimize the risk of infections following cystoscopy, it is important to pay close attention to the reprocessing and cleaning of cystoscopes.

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