Background: Human muscle satellite (stem) cells (MuSCs) are essential for investigating muscle physiology, regeneration, and disease mechanisms. Primary cultures derived directly from human tissues offer a more physiologically relevant model than immortalized cell lines. However, the isolation and characterization of MuSCs from human upper limb tissues are limited. Therefore, this study aimed to establish and characterize a primary culture system for MuSCs obtained from human upper limb muscle tissue. Methods: Human muscle tissues were obtained from upper limb surgical specimens. Muscle samples were mechanically and enzymatically dissociated to isolate muscle-derived cells, which were cultured under standard growth conditions. Cell morphology and proliferation were monitored during the culture period. Myogenic characteristics were assessed by examining the expression of muscle-specific markers including myogenic regulatory factors and structural proteins. Additionally, myogenic differentiation capacity was evaluated by inducing differentiation and analyzing the formation of multinucleated myotubes. Results: Primary MuSCs were isolated from human upper limb tissues and expanded in vitro. The cultured cells exhibited a typical spindle-shaped morphology and demonstrated significant proliferative capacity. Characterization confirmed the expression of myogenic markers, indicating the presence of muscle-derived precursor cells. Following induction of differentiation, the cells formed multinucleated myotube-like structures and expressed muscle proteins associated with differentiation, highlighting their potential for myogenic differentiation. Conclusion This study established a reliable protocol for isolating and culturing MuSCs from human upper limb tissues. Cultured cells displayed typical myogenic characteristics and differentiation capacity, indicating that this model could be a valuable platform for studying human muscle biology and potential therapeutic applications.

Background: Left bundle branch area pacing (LBBAP) provides physiologic ventricular activation but requires deep lead penetration into the interventricular septum, which can rarely cause various complications.Case presentation: A 57-year-old woman with high-degree atrioventricular block underwent dual-chamber pacemaker implantation with stylet-driven LBBAP via the left axillary vein. Within hours, she developed nausea, vomiting, and frequent ventricular premature contractions with non-sustained ventricular tachycardia, while remaining hemodynamically stable. Transthoracic echocardiography revealed a well-circumscribed echo lucent mass in the mid interventricular septum (15.6 × 24.7 mm) consistent with hematoma, without pericardial effusion or left ventricular outflow tract obstruction. In the absence of clinical deterioration, a conservative strategy with close rhythm monitoring and serial echocardiography was chosen. The hematoma regressed progressively with near-complete resolution at two weeks, and the patient remained asymptomatic with stable lead function at 6-month follow-up. Conclusions Interventricular septal hematoma is a rare complication of LBBAP that may present predominantly with ventricular arrhythmia. In hemodynamically stable patients without mechanical compromise, careful surveillance can allow successful conservative management without surgical intervention.

Background and Objectives: Clinical characteristics and outcomes in acute heart failure (AHF) vary by phenotype. We assessed phenotype-specific features, treatment patterns, and outcomes in a nationwide Korean cohort. Methods: The Korean Heart Failure III registry prospectively enrolled 7,351 AHF admissions at 47 hospitals. Among 6,777 patients with available left ventricular ejection fraction (EF), phenotypes were defined as heart failure with reduced EF (HFrEF, ≤40%), mildly reduced EF (HFmrEF,41–49%), or preserved EF (HFpEF, ≥50%). The primary endpoint was a 12-month composite of all-cause death or heart transplantation, evaluated from index admission and, among hospital survivors, from discharge. We used inverse probability weighting (multinomial generalized boosted models with stabilized, trimmed weights) and weighted Cox proportional-hazards models to estimate hazard ratios (HRs). Results: Phenotype distribution was 58.9% HFrEF, 13.6% HFmrEF, and 27.5% HFpEF. Crude 12-month composite rates from index admission were 13.4% (HFrEF), 12.7% (HFmrEF), and 16.8% (HFpEF). After weighting, from index admission, HFmrEF (HR, 0.892; 95% confidence interval [CI], 0.731–1.088) and HFpEF (HR, 1.101; 95% CI, 0.939–1.291) did not differ from HFrEF; from discharge, HFpEF had modestly higher risk (HR, 1.207; 95% CI, 1.008–1.445) whereas HFmrEF did not (HR, 1.039; 95% CI, 0.844–1.279). Hyponatremia and chronic kidney disease were consistent adverse markers, while angiotensin-converting enzyme inhibitor/ angiotensin II receptor blocker use at discharge was protective. Conclusions Across the EF spectrum, phenotypes showed distinct profiles and risk. Postdischarge risk was modestly higher in HFpEF, supporting phenotype-tailored care and systematic discharge optimization in Korean patients with AHF.

Background and Objectives: Graves’ ophthalmopathy (GO) is an autoimmune inflammatory disorder that can adversely affect quality of life in patients with Graves’ disease (GD). The objective of this study was to characterize the clinical features of patients with GO and to identify risk factors associated with its development and the need for anti-inflammatory treatment. Materials and Methods: In this multicenter, retrospective observational study, 818 patients with GD were identified via electronic medical record review. Clinical characteristics were assessed, and logistic regression analyses were performed to identify risk factors for GO development and the need for anti-inflammatory treatment. Results: Among the 818 patients with GD, 135 (16.5%) developed GO, and 60 (7.3%) of these patients received anti-inflammatory treatment. GO was diagnosed at the time of GD diagnosis in 54.8% of cases, and proptosis and eyelid/orbital swelling were the common presenting features. In multivariable analysis, female sex (odds ratio [OR]: 1.75, confidence interval [CI]: 1.02-3.03), goiter (OR: 1.71, CI: 1.08-2.71), and smoking (ex-smokers: OR, 2.18; 95% CI: 1.02-4.65; current smokers: OR, 3.11; CI, 1.78-5.44) were independently associated with GO development, whereas diabetes (OR: 0.35, CI: 0.14-0.89) was inversely associated. Higher total cholesterol (OR: 1.31, CI: 1.01-1.04) and elevated thyrotropin-binding inhibitory immunoglobulin levels (OR: 1.07, CI: 1.02-1.11) were also significantly associated with the need for anti-inflammatory treatment. Conclusion This study delineated the clinical features of GO and identified risk factors for its development and the need for anti-inflammatory treatment in patients with GD, providing valuable information for the management of GO in Korean patients.

Objective: Perinatal depression often remains undertreated due to concerns about antidepressant exposure during fertility treatment, pregnancy, or breastfeeding. Non-pharmacological, home-based interventions such as transcranial direct current stimulation (tDCS) present a promising alternative; however, real-world evidence in perinatal populations remains limited. Methods: This prospective observational study included 38 women who received infertility, pregnancy, or postpartum treatment at four hospitals in South Korea. Participants self-administered anodal tDCS targeting the left dorsolateral prefrontal cortex for 20–28 sessions over 4 weeks. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (CES-D) at baseline and weeks 2, 4, and 8. Subjective health perception was measured at baseline using a 5-point Likert scale. Results: Time had a significant effect on depressive symptoms (Wald χ2=90.75, p<0.001), with the largest reduction observed during the first 2 weeks. The CES-D scores remained significantly lower than baseline at week 8, 4 weeks after treatment ended. Subjective health perception was significantly associated with baseline depression severity (Wald χ2=26.41, p<0.001), and its interaction with time was also significant (Wald χ2=320.18, p<0.001). Participants with poorer perceived health (scores 4–5) experienced greater depressive symptom reductions than those with more favorable perceptions (scores 1–2). Conclusion Home-based tDCS was feasible and associated with clinically meaningful improvement in depressive symptoms among perinatal women. Those who initially perceived their health more negatively showed greater response, suggesting subjective health perception may serve as a useful moderator and potential marker to inform personalized treatment strategies.

Background: Transthyretin amyloidosis, a protein-misfolding disorder characterized by systemic amyloid deposition, can be classified as wild-type transthyretin amyloidosis (ATTRwt) or hereditary transthyretin amyloidosis (ATTRv), depending on the presence of transthyretin (TTR) gene variants. We examined the genetic distribution of TTR variants in Korean patients diagnosed with ATTRv. Methods: We retrospectively reviewed 801 participants who underwent TTR analysis at Samsung Medical Center from 2012 to 2024. The participants were categorized into two groups: in-house probands or relatives, and externally referred probands or relatives. Results: Pathogenic or likely pathogenic TTR variants were detected in 36 of 165 in-house probands (21.8%), among which D38A was the most frequent variant (50.0%; 18/36), followed by M13dup and E89K (8.3% each). Among referred probands, D38A was predominant (54.5%; 12/22), followed by M13dup (22.7%; 5/22). Cardiac amyloid involvement was the most common manifestation, observed in 97.2% (35/36) of in-house probands with ATTRv, followed by peripheral nervous system (PNS; 94.4%) and autonomic nervous system (ANS; 88.9%) involvement. In contrast, ANS involvement was most prevalent among in-house relatives who underwent organ evaluation (61.5%; 24/39), followed by cardiac (52.1%; 25/48) and PNS (48.7%; 19/39) involvement. Five of the eight in-house relatives harboring M13dup (62.5%) showed organ involvement, primarily in the ANS, supporting the pathogenicity of this variant. Conclusions This study provides the largest single-institution dataset of Korean patients with ATTRv, incorporating systematic organ assessments. The predominance of the unique TTR variants D38A and M13dup delineates a distinct genetic landscape that may facilitate accurate and timely diagnosis of ATTRv in the Korean population.

Background: Fusion genes are major drivers of acute leukemia. Conventional diagnostics are limited in detecting the diverse fusions included in recently updated acute leukemia classifications. We evaluated the fusion detection performance of RNA sequencing (RNAseq) compared with that of conventional diagnostics in patients with acute leukemia. Methods: We retrospectively obtained the data of 101 patients with acute leukemia who underwent conventional diagnostics (i.e., karyotyping, FISH, or multiplex reverse transcription PCR) at diagnosis at Samsung Medical Center, Seoul, Korea, between September 2022 and September 2023. Whole RNA-seq was performed using the Illumina Stranded mRNA Prep kit (Illumina, San Diego, CA, USA). The concordance, sensitivity, and specificity of RNA-seq for fusion gene detection were compared with those of conventional diagnostics. Results: RNA-seq helped identify 52 fusion genes in 51 (50.5%) of 101 patients, with detection rates of 40.7%, 70.3%, 37.5%, and 50% in acute myeloid leukemia, B-cell acute lymphoblastic leukemia, T-cell acute lymphoblastic leukemia, and mixed-phenotype acute leukemia, respectively. RNA-seq showed 83.3% sensitivity and 80.8% concordance with conventional diagnostics; it missed eight fusions, likely because of low transcript abundance or enhancer hijacking. RNA-seq also helped clarify three previously unspecified rearrangements and detected 12 fusions (21.4%) in 56 cases that tested negative with conventional diagnostics, including four novel (KMT2A::THAP12 , RUNX1::PRPF19 , MLLT10::UBE2L6, and FUS::ZNF362) and three rare (HNRNPH1::ERG, RUNX1::USP42, and ETV6::NCOA2) fusions. Conclusions This was the first study to evaluate the performance of whole RNA-seq in fusion detection in patients with acute leukemia in Korea. Incorporating RNA-seq into diagnostic workflows may facilitate earlier and more precise therapeutic decisions and improve prognostic assessment in patients with acute leukemia.

The spleen is frequently referred to as the “silent and forgotten” organ of the abdomen by clinicians and radiologists, primarily because of the secondary nature of most splenic pathologies and their relative rarity compared with hepatic diseases.Nevertheless, the term splenomegaly frequently appears in radiological reports. Although it is often reported in the context of a known underlying cause, it is also commonly used as a purely descriptive term without reference to the underlying etiology.Although splenomegaly may occasionally be idiopathic, it commonly represents an underlying pathological condition.Therefore, radiologists are instrumental in accurately identifying splenomegaly, evaluating plausible differential diagnoses, and guiding appropriate clinical management and workups. Given the wide spectrum of etiologies and overlapping imaging features, a systematic approach is essential to enhance the diagnostic accuracy and clinical relevance. Here, we present a comprehensive literature review of splenomegaly from a radiological perspective, with causes categorized according to pathophysiological mechanisms.

Purpose: Ras association domain family 4 (RASSF4) is a putative tumor suppressor that is frequently inactivated in multiple human cancers. However, its candidacy as a suppressor in gastric tumorigenesis remains undefined. To understand the role for RASSF4 in gastric tumorigenesis, we investigated its expression status in cancer cell lines and tissues and regulatory role in tumor growth. Materials and Methods: RASSF4 expression was analyzed in 13 cancer cell lines and 20 carcinoma tissues using polymerase chain reaction and immunoblot assays. RASSF4 effect on cell proliferation and apoptosis was examined by flow cytometry, colony formation, and [3H]thymidine incorporation assays and its regulation of p53 was determined using cycloheximide chase, promoter reporter, and immunoprecipitation assays. Mouse xenograft assay was performed to verify RASSF4 effect on tumor growth and therapeutic response. Results: RASSF4 expression is epigenetically inactivated in eight of 13 (61.5%) cancer cell lines and 15 of 20 (75%) primary carcinomas. RASSF4 suppresses cell proliferation by inducing a G2/M cell cycle arrest and enhances apoptotic response to therapeutic drugs. RASSF4 is induced in response to genotoxic agents to facilitate stress-induced apoptosis in a highly p53-dependent fashion. Mechanistically, RASSF4 stabilizes p53 through Chk2 activation and its apoptotic function is profoundly impaired by depletion of either p53 or Chk2. RASSF4 attenuates xenograft tumor growth and enhances tumor response to 5-fluorouracil. Clinically, RASSF4 expression correlates strongly with the overall survival of gastric cancer patients. Conclusion RASSF4 suppresses gastric tumor growth through the activation of the Chk2-p53 axis, illuminating the mechanistic consequence of its inactivation in gastric tumorigenesis.