Background: The taxonomic status of house mice (Mus musculus) on the Korean Peninsula has long been debated due to conflicting morphological classifications and limited genetic evidence. Historically, three subspecies (M. m.molossinus, M. m. utsuryonis, and M. m. yamashinai) have been proposed based on external traits, although the validity of these proposals remains uncertain. Thus, this study aimed to integrate genetic and morphological analyses to clarify the phylogenetic relationships of Korean mice relative to the well-known primary M. musculus subspecies and evaluate the taxonomic distinctiveness. Results: Genetic analysis of mitochondrial DNA (cytb gene) from mice across Korea, including islands, mountains, and agricultural fields, confirmed that these mice belong to the Eurasian M. m. musculus lineage. Morphologically, Korean mice exhibited tail ratios consistent with previously assigned subspecies, suggesting these traits represent intraspecific variation within M. m. musculus. Craniometric analyses revealed distinctive features, such as a shorter, narrower premaxillary tooth-patch width and a longer maxillary tooth-row length, thereby distinguishing these mice from laboratory strains derived from M. m. domesticus. These cranial configurations, visualized via three-dimensional micro-computed tomography scans, further supported the morphological divergence of these mice from other subspecies. Conclusions Our findings indicate that Korean house mice belong to a single subspecific group within M. m.musculus, with observed morphological variations reflecting local adaptation rather than distinct taxonomic divisions.The Korean Peninsula likely served as an ecological bridge, facilitating the spatiotemporal diversification of M. m.musculus across East Eurasia. This study resolves longstanding taxonomic ambiguities and underscores the subspecific status of Korean house mice within M. m. musculus. These insights provide a foundation for understanding the biogeographic history of human commensal species and future biomedical research utilizing wild-derived mouse models.

Background and Objectives: Primary prevention (PP) implantable cardioverter-defibrillator (ICD) therapy for ischemic cardiomyopathy (ICM) is underused in Asian countries, including South Korea. Both clinical and hospital factors may influence appropriate ICD use. We evaluated whether determinants of PP ICD implantation differ by hospital implantation volume. Methods: In this prospective, multicenter observational registry (blinded for review), patients eligible for PP ICD were enrolled. Factors associated with ICD implantation—clinical characteristics and hospital-level systems—were examined across 4 large-volume hospitals (≥ 15 implants during the study) and 12 small-volume hospitals (< 15). Multivariable logistic regression identified independent predictors. Results: Among 3,083 ICM patients (2,403 men; median age 70 years), PP ICD implantation rates were 10.8% in large-volume and 5.7% in small-volume hospitals. Across groups, male sex and chronic kidney disease independently predicted ICD implantation. Regarding hospital factors, non-monetary incentives for referral were the sole independent predictor in large-volume centers (odds ratio [OR], 3.55; 95% confidence interval [CI], 2.07–6.10;P < 0.001). In small-volume centers, heart failure conferences (OR, 12.73; 95% CI, 1.72–94.37;P = 0.013), structured education systems (OR, 11.72; 95% CI, 2.45–56.12; P = 0.02), and pacemaker clinics (OR, 11.4; 95% CI, 2.24–58.39; P = 0.003) were independently associated with implantation. Conclusions Clinical predictors of PP ICD use were consistent across hospital volumes, but hospital-level determinants differed. Referral incentives characterized large-volume centers, whereas conferences, education systems, and pacemaker clinics were key in smallvolume centers. Tailored institutional strategies by hospital volume may help close the PP ICD underuse gap and improve evidence-based implementation.

Background: and Purpose Previous research on patients with acute ischemic stroke (AIS) has shown a 0.5% incidence of major gastrointestinal bleeding (GIB) requiring blood transfusion during hospitalization. The existing literature has insufficiently explored the long-term incidence in this population despite the decremental impact of GIB on stroke outcomes. Methods: We analyzed the data from a cohort of patients with AIS admitted to 14 hospitals as part of a nationwide multicenter prospective stroke registry between 2011 and 2013. These patients were followed up for up to 6 years. The occurrence of major GIB events, defined as GIB necessitating at least two units of blood transfusion, was tracked using the National Health Insurance Service claims data. Results: Among 10,818 patients with AIS (male, 59%; mean age, 68±13 years), 947 (8.8%) experienced 1,224 episodes of major GIB over a median follow-up duration of 3.1 years. Remarkably, 20% of 947 patients experienced multiple episodes of major GIB. The incidence peaked in the first month after AIS, reaching 19.2 per 100 person-years, and gradually decreased to approximately one-sixth of this rate by the 2nd year with subsequent stabilization. Multivariable analysis identified the following predictors of major GIB: anemia, estimated glomerular filtration rate <60 mL/min/1.73 m2 , and a 3-month modified Rankin Scale score of ≥4. Conclusion Patients with AIS are susceptible to major GIB, particularly in the first month after the onset of AIS, with the risk decreasing thereafter. Implementing preventive strategies may be important, especially for patients with anemia and impaired renal function at stroke onset and those with a disabling stroke.

Background: and Purpose Previous research on patients with acute ischemic stroke (AIS) has shown a 0.5% incidence of major gastrointestinal bleeding (GIB) requiring blood transfusion during hospitalization. The existing literature has insufficiently explored the long-term incidence in this population despite the decremental impact of GIB on stroke outcomes. Methods: We analyzed the data from a cohort of patients with AIS admitted to 14 hospitals as part of a nationwide multicenter prospective stroke registry between 2011 and 2013. These patients were followed up for up to 6 years. The occurrence of major GIB events, defined as GIB necessitating at least two units of blood transfusion, was tracked using the National Health Insurance Service claims data. Results: Among 10,818 patients with AIS (male, 59%; mean age, 68±13 years), 947 (8.8%) experienced 1,224 episodes of major GIB over a median follow-up duration of 3.1 years. Remarkably, 20% of 947 patients experienced multiple episodes of major GIB. The incidence peaked in the first month after AIS, reaching 19.2 per 100 person-years, and gradually decreased to approximately one-sixth of this rate by the 2nd year with subsequent stabilization. Multivariable analysis identified the following predictors of major GIB: anemia, estimated glomerular filtration rate <60 mL/min/1.73 m2 , and a 3-month modified Rankin Scale score of ≥4. Conclusion Patients with AIS are susceptible to major GIB, particularly in the first month after the onset of AIS, with the risk decreasing thereafter. Implementing preventive strategies may be important, especially for patients with anemia and impaired renal function at stroke onset and those with a disabling stroke.

Background: and Purpose Previous research on patients with acute ischemic stroke (AIS) has shown a 0.5% incidence of major gastrointestinal bleeding (GIB) requiring blood transfusion during hospitalization. The existing literature has insufficiently explored the long-term incidence in this population despite the decremental impact of GIB on stroke outcomes. Methods: We analyzed the data from a cohort of patients with AIS admitted to 14 hospitals as part of a nationwide multicenter prospective stroke registry between 2011 and 2013. These patients were followed up for up to 6 years. The occurrence of major GIB events, defined as GIB necessitating at least two units of blood transfusion, was tracked using the National Health Insurance Service claims data. Results: Among 10,818 patients with AIS (male, 59%; mean age, 68±13 years), 947 (8.8%) experienced 1,224 episodes of major GIB over a median follow-up duration of 3.1 years. Remarkably, 20% of 947 patients experienced multiple episodes of major GIB. The incidence peaked in the first month after AIS, reaching 19.2 per 100 person-years, and gradually decreased to approximately one-sixth of this rate by the 2nd year with subsequent stabilization. Multivariable analysis identified the following predictors of major GIB: anemia, estimated glomerular filtration rate <60 mL/min/1.73 m2 , and a 3-month modified Rankin Scale score of ≥4. Conclusion Patients with AIS are susceptible to major GIB, particularly in the first month after the onset of AIS, with the risk decreasing thereafter. Implementing preventive strategies may be important, especially for patients with anemia and impaired renal function at stroke onset and those with a disabling stroke.

Background: While Korea maintains a low prevalence of human immunodeficiency virus (HIV), the number of newly diagnosed cases has been steadily rising, reaching approximately 1,000 annually in recent years. The 2022 annual report from the Korea Disease Control and Prevention Agency revealed that women living with HIV (WLWH) constitute 6.4% of the total confirmed people living with the HIV population, totaling 1,219 individuals. Despite this, only a few studies have focused on WLWH in Korea. This study aims to analyze the epidemiological and clinical characteristics of WLWH in Korea. Materials and Methods: We retrospectively collected data by reviewing the medical records of all WLWH who visited 10 urban referral hospitals across Korea between January 2005 and May 2023. Results: A total of 443 WLWH were enrolled in this study. The predominant risk exposure was heterosexual contact, with 235 (53%) participants either married or cohabiting with a male partner at their initial clinic visit. Among the participants, 334 (77.7%) were Korean, 27 (6.1%) were Southeast Asian, and 19 (4.3%) were African. Antiretroviral therapy was initiated by 404 WLWH (91.2%). We observed 118 pregnancies in WLWH following their HIV diagnosis, resulting in 78 live births (66.1%), 18 induced abortions (15.2%), 10 pre-viable fetal losses (8.5%), and four stillbirths (3.4%). Over a cumulative follow-up duration of 3,202.1 years, the incidence rates of breast and cervical cancers were both 2.18 per 1,000 person-years. Additionally, the incidence rates of pelvic inflammatory disease, cervical intraepithelial neoplasm (above grade II), and osteoporosis were 4.67, 11.21, and 13.39 per 1,000 patient-years, respectively. Conclusion This is the first multicenter study to investigate the clinical and epidemiological characteristics of WLWH in Korea. The incidence and prevalence of diseases in women, including breast cancer, cervical cancer, and chronic comorbidities, are high in WLWH in Korea; therefore, further research and efforts are needed to manage these diseases.

Background: While Korea maintains a low prevalence of human immunodeficiency virus (HIV), the number of newly diagnosed cases has been steadily rising, reaching approximately 1,000 annually in recent years. The 2022 annual report from the Korea Disease Control and Prevention Agency revealed that women living with HIV (WLWH) constitute 6.4% of the total confirmed people living with the HIV population, totaling 1,219 individuals. Despite this, only a few studies have focused on WLWH in Korea. This study aims to analyze the epidemiological and clinical characteristics of WLWH in Korea. Materials and Methods: We retrospectively collected data by reviewing the medical records of all WLWH who visited 10 urban referral hospitals across Korea between January 2005 and May 2023. Results: A total of 443 WLWH were enrolled in this study. The predominant risk exposure was heterosexual contact, with 235 (53%) participants either married or cohabiting with a male partner at their initial clinic visit. Among the participants, 334 (77.7%) were Korean, 27 (6.1%) were Southeast Asian, and 19 (4.3%) were African. Antiretroviral therapy was initiated by 404 WLWH (91.2%). We observed 118 pregnancies in WLWH following their HIV diagnosis, resulting in 78 live births (66.1%), 18 induced abortions (15.2%), 10 pre-viable fetal losses (8.5%), and four stillbirths (3.4%). Over a cumulative follow-up duration of 3,202.1 years, the incidence rates of breast and cervical cancers were both 2.18 per 1,000 person-years. Additionally, the incidence rates of pelvic inflammatory disease, cervical intraepithelial neoplasm (above grade II), and osteoporosis were 4.67, 11.21, and 13.39 per 1,000 patient-years, respectively. Conclusion This is the first multicenter study to investigate the clinical and epidemiological characteristics of WLWH in Korea. The incidence and prevalence of diseases in women, including breast cancer, cervical cancer, and chronic comorbidities, are high in WLWH in Korea; therefore, further research and efforts are needed to manage these diseases.

Background: While Korea maintains a low prevalence of human immunodeficiency virus (HIV), the number of newly diagnosed cases has been steadily rising, reaching approximately 1,000 annually in recent years. The 2022 annual report from the Korea Disease Control and Prevention Agency revealed that women living with HIV (WLWH) constitute 6.4% of the total confirmed people living with the HIV population, totaling 1,219 individuals. Despite this, only a few studies have focused on WLWH in Korea. This study aims to analyze the epidemiological and clinical characteristics of WLWH in Korea. Materials and Methods: We retrospectively collected data by reviewing the medical records of all WLWH who visited 10 urban referral hospitals across Korea between January 2005 and May 2023. Results: A total of 443 WLWH were enrolled in this study. The predominant risk exposure was heterosexual contact, with 235 (53%) participants either married or cohabiting with a male partner at their initial clinic visit. Among the participants, 334 (77.7%) were Korean, 27 (6.1%) were Southeast Asian, and 19 (4.3%) were African. Antiretroviral therapy was initiated by 404 WLWH (91.2%). We observed 118 pregnancies in WLWH following their HIV diagnosis, resulting in 78 live births (66.1%), 18 induced abortions (15.2%), 10 pre-viable fetal losses (8.5%), and four stillbirths (3.4%). Over a cumulative follow-up duration of 3,202.1 years, the incidence rates of breast and cervical cancers were both 2.18 per 1,000 person-years. Additionally, the incidence rates of pelvic inflammatory disease, cervical intraepithelial neoplasm (above grade II), and osteoporosis were 4.67, 11.21, and 13.39 per 1,000 patient-years, respectively. Conclusion This is the first multicenter study to investigate the clinical and epidemiological characteristics of WLWH in Korea. The incidence and prevalence of diseases in women, including breast cancer, cervical cancer, and chronic comorbidities, are high in WLWH in Korea; therefore, further research and efforts are needed to manage these diseases.

Purpose: This study aims to investigate the diagnostic significance of positron emission tomography/computed tomography (PET/CT) in assessing bone marrow (BM) involvement through a comparison of PET/CT findings with BM biopsy in extranodal natural killer/T-cell lymphoma. Materials and Methods: The medical records of 193 patients were retrospectively reviewed. Patients were categorized as having early-stage (PET-ES) or advanced-stage (PET-AS) disease based on PET/CT results. The BM involvement was classified into three groups according to BM biopsy: gross BM involvement, minimal BM involvement (defined as the presence of a limited number of Epstein-Barr virus–positive cells in BM), and no involvement. Calculations of the accuracy of PET/CT in detecting BM involvement and analysis of the clinical outcomes (progression-free survival [PFS] and overall survival [OS]) according to the BM biopsy status were performed. Results: PET/CT exhibited a sensitivity of 64.7% and a specificity of 96.0% in detecting gross BM involvement. For detecting any (both gross and minimal) BM involvement, the sensitivity was 30.4%, while the specificity was 99.0%. Only one patient (0.7%) demonstrated gross BM involvement among the PET-ES group. Survival outcomes of the PET-ES group with minimal BM involvement (3-year PFS, 55.6%; OS, 77.0%) were closer to those of the PET-ES group with no BM involvement (3-year PFS, 62.2%; OS, 80.6%) than to those of the PET-AS group (3-year PFS, 20.1%; OS, 29.9%). Conclusion PET/CT exhibits high specificity, but moderate and low sensitivity in detecting gross and minimal BM involvement, respectively. The clinical significance of minimal BM involvement for patients in the PET-ES group may be limited.