1.Understanding of Patients with Severe COVID-19 Using Lung Ultrasound
Seo-Hee YANG ; Eun Ju PARK ; Jung-Hyun KIM ; Jin Woo SONG ; Young-Jae CHO
Tuberculosis and Respiratory Diseases 2025;88(2):380-387
Background:
Lung ultrasound (LUS) has proven valuable in the initial assessment of coronavirus disease 2019 (COVID-19), but its role in detecting pulmonary fibrosis following intensive care remains unclear. This study aims to assess the presence of pulmonary sequelae and fibrosis-like changes using LUS in survivors of severe COVID-19 pneumonia one month after discharge.
Methods:
We prospectively enrolled patients with severe COVID-19 who required mechanical ventilation in the intensive care unit (ICU) and conducted LUS assessments from admission to the outpatient visit after discharge. We tracked changes in key LUS findings and applied our proprietary LUS scoring system. To evaluate LUS accuracy, we correlated measured LUS values with computed tomography scores.
Results:
We evaluated B-line presence, pleural thickness, and consolidation in 14 eligible patients. The LUS scores exhibited minimal changes, with values of 19.1, 19.2, and 17.5 at admission, discharge, and the outpatient visit, respectively. Notably, the number of B-lines decreased significantly, from 1.92 at admission to 0.56 at the outpatient visit (p<0.05), while pleural thickness increased significantly, from 2.05 at admission to 2.48 at the outpatient visit (p≤0.05).
Conclusion
This study demonstrates that LUS can track changes in lung abnormalities in severe COVID-19 patients from ICU admission through to outpatient follow-up. While pleural thickening and B-line patterns showed significant changes, no correlation was found between LUS and high-resolution computed tomography fibrosis scores. These findings suggest that LUS may serve as a supplementary tool for assessing pulmonary recovery in severe COVID-19 cases.
2.KEAP1-NRF2 Pathway as a Novel Therapeutic Target for EGFR-Mutant Non-small Cell Lung Cancer
Jae-Sun CHOI ; Hye-Min KANG ; Kiyong NA ; Jiwon KIM ; Tae-Woo KIM ; Junyang JUNG ; Heejin LIM ; Hyewon SEO ; Seung Hyeun LEE
Tuberculosis and Respiratory Diseases 2025;88(1):138-149
Background:
Kelch-like ECH-associated protein 1 (KEAP1)–nuclear factor erythroid- 2-related factor 2 (NRF2) pathway is a major regulator protecting cells from oxidative and metabolic stress. Studies have revealed that this pathway is involved in mediating resistance to cytotoxic chemotherapy and immunotherapy; however, its implications in oncogene-addicted tumors are largely unknown. This study aimed to elucidate whether this pathway could be a potential therapeutic target for epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer.
Methods:
We measured the baseline expression of NRF2 using EGFR-mutant parental cells and acquired gefitinib resistant cells. We investigated whether NRF2 inhibition affected cell death in vitro and tumor growth in vivo using a xenograft mouse model, and compared the transcriptional changes before and after NRF2 inhibition.
Results:
Baseline NRF2 expression was enhanced in PC9 and PC9 with gefitinib resistance (PC9/GR) cells than in other cell lines, with a more prominent expression in PC9/ GR. The NRF2 inhibitor induced NRF2 downregulation and cell death in a dose-dependent manner. Cotreatment with an NRF2 inhibitor enhanced osimertinib-induced cell death in vitro, and potentiated tumor growth inhibition in a PC9/GR xenograft model. Finally, RNA sequencing revealed that NRF2 inhibition resulted in the altered expression of multiple genes involved in various signaling pathways.
Conclusion
We identified that NRF2 inhibition enhanced cell death and inhibited tumor growth in tyrosine kinase inhibitor (TKI)-resistant lung cancer with EGFR-mutation. Thus, NRF2 modulation may be a novel therapeutic strategy to overcome the resistance to EGFR-TKIs.
3.Vitamin D Attenuates Non-Alcoholic Fatty Liver Disease in High-Fat Diet-Induced Obesity Murine Model
Sook In CHUNG ; Lin LIANG ; Heejae HAN ; Kyung Hee PARK ; Jae-Hyun LEE ; Jung-Won PARK
Yonsei Medical Journal 2025;66(2):75-86
Purpose:
Obesity and metabolic syndrome are acknowledged as key factors contributing to the development of non-alcoholic fatty liver disease (NAFLD). Vitamin D (VitD) is a multifaceted secosteroid hormone known for its anti-fibrotic and anti-inflammatory properties, with its deficiency often linked to obesity. Our study aimed to investigate whether VitD supplementation could mitigate the liver pathology associated with NAFLD.
Materials and Methods:
The NAFLD model was developed by subjecting male C57BL/6 mice to a high-fat diet (HFD) for 14 weeks.These mice were supplemented with VitD through intraperitoneal injection at a dosage of 7 μg/kg, administered three times per week for 7 weeks.
Results:
HFD resulted in VitD deficiency, insulin resistance, and increased liver weight. It elevated serum levels of liver aminotransferases and triglyceride, ultimately leading to steatohepatitis with fibrosis. This model exhibited increased levels of transforming growth factor (TGF)-β1, pro-inflammatory cytokines, HNF4α transcription factors, reactive oxygen species (ROS), renin-angiotensin system activity, and epithelial-mesenchymal transitions (EMT) within the liver. Supplementation with VitD resulted in the recovery of liver weight, improvement in histologic features associated with steatohepatitis, and reduction in alanine aminotransferases and triglyceride levels induced by the HFD. Additionally, it mitigated the HFD-induced over-expressions of TGF-β1 and fibrosis-related genes, along with pro-inflammatory cytokines and ROS. Notably, no adverse effect was found due to VitD supplementation in this model.
Conclusion
VitD ameliorates steatohepatitis within obesity-induced NAFLD through its multifaceted pathways. VitD supplementation emerges as a potentially safe, cost-effective, and direct treatment approach for NAFLD patients dealing with obesity or metabolic dysfunction.
4.Non-Inferiority Analysis of Electrocardiography Analysis Application vs. Point-of-Care Ultrasound for Screening Left Ventricular Dysfunction
Jin Hee KIM ; Jae Yun JUNG ; Joonghee KIM ; Youngjin CHO ; Eunkyoung LEE ; Dahyeon SON
Yonsei Medical Journal 2025;66(3):172-178
Purpose:
Point-of-care ultrasound (POCUS) is widely used for heart function evaluation in emergency departments (EDs), but requires specific equipment and skilled operators. This study evaluates the diagnostic accuracy of a mobile application for estimating left ventricular (LV) systolic dysfunction [left ventricular ejection fraction (LVEF) <40%] using electrocardiography (ECG) and tests its non-inferiority to POCUS.
Materials and Methods:
Patients (aged ≥20 years) were included if they had both a POCUS-based EF evaluation and an ECG within 24 hours of their ED visit between January and May 2022, along with formal echocardiography within 2 weeks before or after the visit. A mobile app (ECG Buddy, EB) estimated LVEF (EF from EB) and the risk of LV dysfunction (LV-Dysfunction score) from ECG waveforms, which were compared to NT-proBNP levels and POCUS-evaluated LVEF (EF from POCUS). A non-inferiority margin was set at an area under the curve (AUC) difference of 0.05.
Results:
Of the 181 patients included, 37 (20.4%) exhibited LV dysfunction. The AUCs for screening LV dysfunction using POCUS and NT-proBNP were 0.885 and 0.822, respectively. EF from EB and LV-Dysfunction score outperformed NT-proBNP, with AUCs of 0.893 and 0.884, respectively (p=0.017 and p=0.030, respectively). EF from EB was non-inferior to EF from POCUS, while LV-Dysfunction score narrowly missed the mark. A subgroup analysis of sinus-origin rhythm ECGs supported the non-inferiority of both EF from EB and LV-Dysfunction score to EF from POCUS.
Conclusion
A smartphone application that analyzes ECG image can screen for LV dysfunction with a level of accuracy comparable to that of POCUS.
5.Mixture of Mastic Gum and Peppermint Extracts Promotes Hair Growth and Health in Vitro and in C57BL/6 Mice
Seoyoon HAM ; Young In LEE ; Yujin JANG ; Sang Gu LEE ; Jangmi SUK ; Inhee JUNG ; Jae Hyun PARK ; Ju Hee LEE
Yonsei Medical Journal 2025;66(5):310-320
Purpose:
Hair disorders, which are often attributed to conditions associated with a shortened anagen growth phase, oxidative stress, and hormonal dysregulation, especially during aging, have profound psychological implications. Currently, only minoxidil has been approved as a topical hair growth solution; thus, alternative therapies for treating hair loss and promoting hair health are urgently needed. Herein, we aimed to develop and assess a novel method to promote hair growth and health using mastic (Pistacia lentiscus) gum and peppermint (Mentha piperita L.) extracts.
Materials and Methods:
After determining the optimal ratio of mastic gum and peppermint extracts, we performed in vitro and in vivo experiments to verify the efficacy of the 7:3 mastic gum-peppermint mixture (MP73; FHH-MG) for enhancing hair growth and health.
Results:
Mastic gum significantly promoted cell proliferation and demonstrated synergistic benefits when combined with peppermint extract. In vitro, FHH-MG increased human dermal follicle papilla cell proliferation and demonstrated anti-inflammatory and antioxidant effects. In vivo, treatment with FHH-MG dose-dependently enhanced hair growth and gloss and increased the expression of vascular endothelial growth factor, epidermal growth factor, β-catenin, and insulin-like growth factor-1 in C57BL/6 mice compared to the negative control.
Conclusion
The novel mixture exhibited hair growth-promoting effects in C57BL/6 mice; thus, FHH-MG may serve as a botanical alternative for hair growth and health promotion.
6.Early Administration of Nelonemdaz May Improve the Stroke Outcomes in Patients With Acute Stroke
Jin Soo LEE ; Ji Sung LEE ; Seong Hwan AHN ; Hyun Goo KANG ; Tae-Jin SONG ; Dong-Ick SHIN ; Hee-Joon BAE ; Chang Hun KIM ; Sung Hyuk HEO ; Jae-Kwan CHA ; Yeong Bae LEE ; Eung Gyu KIM ; Man Seok PARK ; Hee-Kwon PARK ; Jinkwon KIM ; Sungwook YU ; Heejung MO ; Sung Il SOHN ; Jee Hyun KWON ; Jae Guk KIM ; Young Seo KIM ; Jay Chol CHOI ; Yang-Ha HWANG ; Keun Hwa JUNG ; Soo-Kyoung KIM ; Woo Keun SEO ; Jung Hwa SEO ; Joonsang YOO ; Jun Young CHANG ; Mooseok PARK ; Kyu Sun YUM ; Chun San AN ; Byoung Joo GWAG ; Dennis W. CHOI ; Ji Man HONG ; Sun U. KWON ;
Journal of Stroke 2025;27(2):279-283
7.Unilateral lower extremity lymphedema followed by COVID-19 vaccination in patients with cervical cancer history: two case reports
Journal of Yeungnam Medical Science 2025;42(1):23-
The coronavirus disease 2019 (COVID-19) pandemic prompted the development of messenger RNA vaccines. Following extensive vaccination campaigns worldwide, several adverse reactions to these vaccines have been reported. This is a case series of unilateral lower extremity lymphedema after COVID-19 vaccination in two patients with a history of cervical cancer. An 82-year-old woman and a 68-year-old woman visited the outpatient clinic with unilateral leg edema after receiving a COVID-19 booster vaccine (BNT162b2; Pfizer-BioNTech) in the deltoid muscle. Both patients had a common history of cervical cancer treated with surgery, chemotherapy, and radiotherapy and were in complete remission. Gynecological evaluations, including laboratory and imaging studies, revealed no specific findings. Lymphoscintigraphy revealed delayed lymphatic drainage with diffuse dermal backflow in a unilateral lower extremity. This case series explores adverse reactions to COVID-19 vaccination in patients who are at high risk of developing lymphedema, providing novel data for similar clinical presentations.
8.Resident shortages and their impact on surgical care, defensive medicine, and patient management: a retrospective study in South Korea
Jeong Hee HAN ; Byoung Chul LEE ; Jung Bum CHOI ; Hong Jae JO ; Jae Kyun PARK ; Hyae Jin KIM ; Eun Ji PARK ; Young Hoon JUNG ; Chang In CHOI
Korean Journal of Clinical Oncology 2025;21(1):32-39
Purpose:
This study aimed to evaluate the impact of declining surgical residency program enrollment on patient care and outcomes in colorectal cancer surgeries.
Methods:
This retrospective observational study included 676 patients (410 males; median age: 69 years) who underwent colorectal cancer surgery at Pusan National University Hospital between January 2018 and June 2024. Patients were divided into Group A (before December 31, 2023; with residents) and Group B (after January 1, 2024; without residents). All surgeries were performed by a single attending surgeon.
Results:
Preoperative variables were comparable between groups. Group A had more emergency and open surgeries, and a higher proportion of advanced-stage cancers. Overall complication rates were similar, but Group B had a longer hospital stay (9.72 days vs. 11.95 days). Specific complications such as anastomotic leakage and surgical site infections differed significantly. The overall number of surgical procedures declined markedly in 2024 compared to 2018 (77.1% vs. 49.9%).
Conclusion
The absence of residents did not increase overall complication rates but was associated with longer hospital stays and shifts in clinical practice. Greater reliance on attending surgeons contributed to more defensive decision-making and conservative patient management. Addressing these issues requires systemic reforms, including multidisciplinary collaboration and legal protections to improve surgical care.
10.Characteristics and Prevalence of Sequelae after COVID-19: A Longitudinal Cohort Study
Se Ju LEE ; Yae Jee BAEK ; Su Hwan LEE ; Jung Ho KIM ; Jin Young AHN ; Jooyun KIM ; Ji Hoon JEON ; Hyeri SEOK ; Won Suk CHOI ; Dae Won PARK ; Yunsang CHOI ; Kyoung-Ho SONG ; Eu Suk KIM ; Hong Bin KIM ; Jae-Hoon KO ; Kyong Ran PECK ; Jae-Phil CHOI ; Jun Hyoung KIM ; Hee-Sung KIM ; Hye Won JEONG ; Jun Yong CHOI
Infection and Chemotherapy 2025;57(1):72-80
Background:
The World Health Organization has declared the end of the coronavirus disease 2019 (COVID-19) public health emergency. However, this did not indicate the end of COVID-19. Several months after the infection, numerous patients complain of respiratory or nonspecific symptoms; this condition is called long COVID. Even patients with mild COVID-19 can experience long COVID, thus the burden of long COVID remains considerable. Therefore, we conducted this study to comprehensively analyze the effects of long COVID using multi-faceted assessments.
Materials and Methods:
We conducted a prospective cohort study involving patients diagnosed with COVID-19 between February 2020 and September 2021 in six tertiary hospitals in Korea. Patients were followed up at 1, 3, 6, 12, 18, and 24 months after discharge. Long COVID was defined as the persistence of three or more COVID-19-related symptoms. The primary outcome of this study was the prevalence of long COVID after the period of COVID-19.
Results:
During the study period, 290 patients were enrolled. Among them, 54.5 and 34.6% experienced long COVID within 6 months and after more than 18 months, respectively. Several patients showed abnormal results when tested for post-traumatic stress disorder (17.4%) and anxiety (31.9%) after 18 months. In patients who underwent follow-up chest computed tomography 18 months after COVID-19, abnormal findings remained at 51.9%. Males (odds ratio [OR], 0.17; 95% confidence interval [CI], 0.05–0.53; P=0.004) and elderly (OR, 1.04; 95% CI, 1.00–1.09; P=0.04) showed a significant association with long COVID after 12–18 months in a multivariable logistic regression analysis.
Conclusion
Many patients still showed long COVID after 18 months post SARS-CoV-2 infection. When managing these patients, the assessment of multiple aspects is necessary.

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