Mitochondrial stress and the dysregulated mitochondrial unfolded protein response (UPRmt) are linked to various diseases, including metabolic disorders, neurodegenerative diseases, and cancer. Mitokines, signaling molecules released by mitochondrial stress response and UPRmt, are crucial mediators of inter-organ communication and influence systemic metabolic and physiological processes. In this review, we provide a comprehensive overview of mitokines, including their regulation by exercise and lifestyle interventions and their implications for various diseases. The endocrine actions of mitokines related to mitochondrial stress and adaptations are highlighted, specifically the broad functions of fibroblast growth factor 21 and growth differentiation factor 15, as well as their specific actions in regulating inter-tissue communication and metabolic homeostasis. Finally, we discuss the potential of physiological and genetic interventions to reduce the hazards associated with dysregulated mitokine signaling and preserve an equilibrium in mitochondrial stress-induced responses. This review provides valuable insights into the mechanisms underlying mitochondrial regulation of health and disease by exploring mitokine interactions and their regulation, which will facilitate the development of targeted therapies and personalized interventions to improve health outcomes and quality of life.

Thyroid nodules represent a prevalent condition that is detectable via palpation or ultrasound. In recent years, there has been a paradigm shift toward enhanced diagnostic precision and less aggressive therapeutic approaches, highlighting the growing necessity for tailored clinical recommendations to optimize patient outcomes. The Korean Thyroid Association (KTA) has developed guidelines for managing patients with thyroid nodules, following a comprehensive review by task force members of the relevant literature identified via electronic database searches. The recommendations are provided with a level of recommendation for each section. The guidelines encompass thyroid cancer screening in high-risk groups, appropriate diagnostic methods for thyroid nodules, role of pathologic and molecular marker testing in making a diagnosis, long-term follow-up and treatment of benign thyroid nodules, and special considerations for pregnant women. The major revisions that were made in the 2023 guidelines were the definition of high-risk groups for thyroid cancer screening, application of the revised Korean Thyroid Imaging Reporting and Data System (K-TIRADS), addition of the role of core needle biopsy and molecular marker tests, application of active surveillance in patients with low-risk papillary thyroid microcarcinoma, and updated indications for nonsurgical treatment of benign thyroid nodules. In the 2024 revision of the KTA guidelines for thyroid cancer, the evidence for some recommendations has been updated to address the tumor size in the context of active surveillance in patients with low-risk thyroid cancer and the surgical size cutoff. These evidence-based recommendations serve to inform clinical decision-making in the management of thyroid nodules, thereby facilitating the delivery of optimal and efficacious treatments to patients.

Differentiated thyroid cancer demonstrates a wide range of clinical presentations, from very indolent cases to those with an aggressive prognosis. Therefore, diagnosing and treating each cancer appropriately based on its risk status is important. The Korean Thyroid Association (KTA) has provided and amended the clinical guidelines for thyroid cancer management since 2007. The main changes in this revised 2024 guideline include 1) individualization of surgical extent according to pathological tests and clinical findings, 2) application of active surveillance in low-risk papillary thyroid microcarcinoma, 3) indications for minimally invasive surgery, 4) adoption of World Health Organization pathological diagnostic criteria and definition of terminology in Korean, 5) update on literature evidence of recurrence risk for initial risk stratification, 6) addition of the role of molecular testing, 7) addition of definition of initial risk stratification and targeting thyroid stimulating hormone (TSH) concentrations according to ongoing risk stratification (ORS), 8) addition of treatment of perioperative hypoparathyroidism, 9) update on systemic chemotherapy, and 10) addition of treatment for pediatric patients with thyroid cancer.

Thyroid nodules are a prevalent condition that can be detected through palpation or ultrasound. However, a small fraction of these nodules can be cancerous, and even benign nodules can cause symptoms if they grow and compress surrounding tissue. As such, it is important to monitor thyroid nodules and determine appropriate treatment options. In recent years, there has been a shift towards enhancing diagnostic accuracy and less aggressive treatment options. As a result, there is a growing need for the development of appropriate recommendations for their clinical application to ensure optimal patient outcomes. The present clinical practice guideline was developed by extracting the nodule section from the prior version of guidelines and updating it to fit the Korean circumstances. Task force members reviewed relevant studies selected after electronic database searching, and the recommendations are provided with a level of recommendation for each section. The revised guideline includes recommendations for thyroid cancer screening in high-risk groups, appropriate diagnostic methods for thyroid nodules, the role of pathological and molecular marker tests in diagnosis, long-term follow-up and treatment of benign thyroid nodules, and special considerations for pregnant women. The major changes in this revision are the definition of high-risk groups for thyroid cancer screening, the application of the revised Korean Thyroid Imaging Reporting and Data System (K-TIRADS), the addition of the role of core needle biopsy and molecular marker tests, the application of active surveillance in low-risk papillary thyroid microcarcinoma, and updated indications for non-surgical treatment of benign thyroid nodules. These evidence-based recommendations are expected to assist in clinical decision-making for thyroid nodule management, ensuring that patients receive the most appropriate and effective treatment options.

Vaccination against Newcastle disease (ND) is the most effective means of controlling the disease, and these vaccines are commercialized only after their safety and effectiveness have been verified through tests that comply with Korean Standards of National Lot Release for Veterinary Biologics. This study investigated whether a relatively convenient and safe serological test can be used in place of the challenge test using highly virulent ND virus. Hemagglutination inhibition (HI) assay and enzyme-linked immunosorbent assay (ELISA) were considered positive of log2 2 or more and cutoff value of 200 or more, respectively, in both live and inactivated vaccines. However, when the antibody levels of the live and inactivated vaccines induced using the Ulster 2C, KBNP-C4152R2L, and K148/08 strains were compared, the antibody titers for inactivated vaccines were significantly higher than those for live vaccines in both the HI assay and ELISA. A strong positive correlation was observed between HI and ELISA antibody titers. The live vaccines corresponded to a survival rates of ≥ 80% and the inactivated vaccines corresponded to 100% survival rates. This study confirmed that standard efficacy tests can serve as serological tests, and can replace the challenge test and that the vaccine approval process can be improved.

Objectives: : We estimated the overall and age-specific percentages of the Korean population with presumed immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as of April 2022 using the national registry. Methods: : We used the national coronavirus disease 2019 (COVID-19) infection and vaccination registry from South Korea, as described to define individuals with a previous history of COVID-19 infection, vaccination, or both, as persons with presumed immunity. Results: : Of a total of 53,304,627 observed persons, 24.4% had vaccination and infection, 58.1% had vaccination and no infection, 7.6% had infection and no vaccination, and 9.9% had no immunity. The SARS-CoV-2 Omicron variant emerged at a time when the presumed population immunity ranged from 80% to 85%; however, nearly half of the children were presumed to have no immunity. Conclusion : We report a gap in population immunity, with lower presumed protection in children than in adults. The approach presented in this work can provide valuable informed tools to assist vaccine policy-making at a national level.

Purpose: We report the clinical characteristics and the primary underlying diseases of patients at high risk for failure of penetrating keratoplasty (PKP) in Korea. Methods: Patients at high risk of PKP failure among those who visited the ophthalmological clinics of tertiary care hospitals in Korea from April 2019 to April 2020 and who were indicated for PKP were retrospectively enrolled. We epidemiologically investigated 119 eyes of 104 patients via medical chart review. Results: Herpes simplex virus (HSV) keratitis was the most common primary underlying disease (26.1%). The most common primary cause of poor bilateral visual acuity was Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) (41.7%) followed by chemical burns (19.4%). Of the 119 eyes, 40.3% had a history of previous PKP and 20.2% had undergone three or more PKP. The average number of prior PKPs was 1.02 ± 1.46. Corneal neovascularization and corneal opacity were reported in 82.4 and 92.4% of cases, respectively. As the severity of these conditions increased, the eye distributions became larger. Of all patients, 47.9 and 31.9%, respectively, received the highest corneal neovascularization and corneal opacity scores. Conclusions Our study of patients at high risk of PKP failure improves our understanding of the relevant clinical characteristics and primary underlying diseases. Such patients require careful observation and aggressive treatment. Possible alternatives to PKP should be considered if PKP consistently fails. This study will aid clinicians in deciding whether to proceed to surgery if a poor postoperative prognosis is predictable.

Objective: Emphysema and small-airway disease are the two major components of chronic obstructive pulmonary disease (COPD). We propose a novel method of quantitative computed tomography (CT) emphysema air-trapping composite (EAtC) mapping to assess each COPD component. We analyzed the potential use of this method for assessing lung function in patients with COPD. Materials and Methods: A total of 584 patients with COPD underwent inspiration and expiration CTs. Using pairwise analysis of inspiration and expiration CTs with non-rigid registration, EAtC mapping classified lung parenchyma into three areas: Normal, functional air trapping (fAT), and emphysema (Emph). We defined fAT as the area with a density change of less than 60 Hounsfield units (HU) between inspiration and expiration CTs among areas with a density less than -856 HU on inspiration CT. The volume fraction of each area was compared with clinical parameters and pulmonary function tests (PFTs). The results were compared with those of parametric response mapping (PRM) analysis. Results: The relative volumes of the EAtC classes differed according to the Global Initiative for Chronic Obstructive Lung Disease stages (p < 0.001). Each class showed moderate correlations with forced expiratory volume in 1 second (FEV 1) and FEV 1/forced vital capacity (FVC) (r = -0.659–0.674, p < 0.001). Both fAT and Emph were significant predictors of FEV 1 and FEV 1/FVC (R2 = 0.352 and 0.488, respectively; p < 0.001). fAT was a significant predictor of mean forced expiratory flow between 25% and 75% and residual volume/total vital capacity (R2 = 0.264 and 0.233, respectively; p < 0.001), while Emph and age were significant predictors of carbon monoxide diffusing capacity (R2 = 0.303; p < 0.001). fAT showed better correlations with PFTs than with small-airway disease on PRM. Conclusion The proposed quantitative CT EAtC mapping provides comprehensive lung functional information on each disease component of COPD, which may serve as an imaging biomarker of lung function.

Objective: Emphysema and small-airway disease are the two major components of chronic obstructive pulmonary disease (COPD). We propose a novel method of quantitative computed tomography (CT) emphysema air-trapping composite (EAtC) mapping to assess each COPD component. We analyzed the potential use of this method for assessing lung function in patients with COPD. Materials and Methods: A total of 584 patients with COPD underwent inspiration and expiration CTs. Using pairwise analysis of inspiration and expiration CTs with non-rigid registration, EAtC mapping classified lung parenchyma into three areas: Normal, functional air trapping (fAT), and emphysema (Emph). We defined fAT as the area with a density change of less than 60 Hounsfield units (HU) between inspiration and expiration CTs among areas with a density less than -856 HU on inspiration CT. The volume fraction of each area was compared with clinical parameters and pulmonary function tests (PFTs). The results were compared with those of parametric response mapping (PRM) analysis. Results: The relative volumes of the EAtC classes differed according to the Global Initiative for Chronic Obstructive Lung Disease stages (p < 0.001). Each class showed moderate correlations with forced expiratory volume in 1 second (FEV 1) and FEV 1/forced vital capacity (FVC) (r = -0.659–0.674, p < 0.001). Both fAT and Emph were significant predictors of FEV 1 and FEV 1/FVC (R2 = 0.352 and 0.488, respectively; p < 0.001). fAT was a significant predictor of mean forced expiratory flow between 25% and 75% and residual volume/total vital capacity (R2 = 0.264 and 0.233, respectively; p < 0.001), while Emph and age were significant predictors of carbon monoxide diffusing capacity (R2 = 0.303; p < 0.001). fAT showed better correlations with PFTs than with small-airway disease on PRM. Conclusion The proposed quantitative CT EAtC mapping provides comprehensive lung functional information on each disease component of COPD, which may serve as an imaging biomarker of lung function.

Background: : Emergency physicians are increasingly participating in brain-death organ tissue donation (OTD).It is difficult communication to inform family members about suspected brain-death and potential donor.This study sought to explore the experiences and communication of emergency physicians in brain-death OTD. Methods: : This is a qualitative study that interviewed 10 experienced emergency physicians with brain-death OTD and analyzed the data by thematic analysis method. Results: : The study revealed 20 subthemes and 5 themes; 1) Families who are invited to donate organs make decisions after long periods of consideration by the entire family, 2) It is uncomfortable to recommend organ donation, 3) Explaining and obtaining consent is ‘the hardest job’ for the attending physician, 4) The way the attending physician does ‘the hardest job’ is by explaining, 5) Passively solicit donation. Conclusion : The experienced emergency physicians with brain-death OTD were using methods of communication to understand and sympathized with the family members and had abundant experiences. The findings of this study will help inexperienced emergency physicians with brain-death OTD.