1.Diagnostic Accuracy of Serological Tests for Mycoplasma pneumoniae Infections in Children with Pneumonia, Based on Symptom Onset
Gahee KIM ; Ki Wook YUN ; Dayun KANG ; Taek Jin LEE ; Byung Wook EUN ; Hyunju LEE ; Yae-Jean KIM ; Doo Ri KIM ; Areum SHIN ; Hyun Mi KANG ; Ye Ji KIM ; Byung Ok KWAK ; Younghee LEE ; Ye Kyung KIM ; Young June CHOE ; Woosuck SUH ; Kyo Jin JO ; Kyung-Ran KIM ; Eun Young CHO ; Kyung Min KIM ; Joon Kee LEE ; Su Eun PARK
Annals of Laboratory Medicine 2026;46(2):162-170
Background:
Mycoplasma pneumoniae is a major cause of community-acquired pneumonia (CAP) in children, with a rising incidence of macrolide resistance. Early diagnosis is crucial for reducing the disease burden; however, current diagnostic tools have limitations.We evaluated the diagnostic accuracy of serological assays and their performance based on symptom onset in children with CAP.
Methods:
From September 2023 to September 2024, we prospectively enrolled children with CAP, classified as M. pneumoniae pneumonia (MPP) or non-MPP, from 16 hospitals in Korea. Serological testing included chemiluminescence immunoassay (CLIA) and ELISA for detecting IgM and IgG, along with particle agglutination (PA) for total antibody measurements. Serological responses were analyzed at different times after symptom onset (0–4, 5–9, and 10–21 days).
Results:
Among 472 children with CAP (362 MPP, 110 non-MPP), 138 (29.2%) underwent PA testing, and 334 (70.8%) underwent IgM testing. PA at a 1:640 cutoff showed 48.0% sensitivity and 100% specificity. CLIA and ELISA showed comparable sensitivities (69.1% vs. 69.2%) and specificities (76.9% vs. 66.7%) for IgM testing. Seropositivity increased significantly with time since symptom onset (P for trend < 0.001), reaching 97.9% for IgM, 62.5% for IgG, and 94.7% for PA at 10–21 days.
Conclusions
The time post-symptom onset significantly influenced the diagnostic utility of serological tests for pediatric MPP, which showed limited value during the early stage of illness. These findings emphasize the importance of symptom onset-based interpretation of serological test results and their utility in complementing PCR when optimizing MPP diagnosis in children.
2.Macro-Aspartate Aminotransferase Elevation in a Patient with Chronic Hepatitis B
Nae-Yun HEO ; Jae-Hoon KIM ; Seungha PARK ; Joon Hyuk CHOI ; Tae Oh KIM ; Jin LEE ; Yong Eun PARK ; Kyung Ran JUN
The Korean Journal of Gastroenterology 2026;86(2):122-127
Although aspartate aminotransferase (AST) is a serum marker of hepatocellular damage in chronic hepatitis, it is difficult to interpret very high AST levels with concurrent low alanine aminotransferase (ALT) levels. Macro-AST is an immunoglobulin-AST complex that can present as aberrant high enzymatic activity without significant inflammation in the liver. Two patients with chronic hepatitis B presented with disproportionate AST elevations. Their plasma samples were precipitated with polyethylene glycol (PEG) and stored at 4°C for macro-AST determinations. In Case 1, PEG precipitation showed 100% removal of AST activity, and refrigerated storage resulted in a ~70% decline over seven days, confirming macro-AST. In Case 2, both tests showed minimal changes, suggesting that macro-AST was unlikely. The AST levels normalized after antiviral therapy, suggesting immune-active hepatitis as the probable cause, but the other contributing factors could not be completely excluded. The abrupt decrease in AST activity after PEG precipitation and during refrigeration storage suggests that relatively high AST values compared to ALT might be attributed to the presence of macro-AST.These non-invasive methods for detecting macroenzymes might help the patient avoid unnecessary further work-ups.
3.Exosomes from Human Embryonic Stem Cell-Derived Mesenchymal Stem Cells Protect Lung Epithelium and Attenuate Fibrosis
Sangryul CHA ; Jooyeon LEE ; Jimin JANG ; Yeongcheol KIM ; Dahee HAN ; Seok-Ho HONG ; Seung-Jin KIM ; Dae-Hee LEE ; Chung Hyeun MA ; Han Pil LEE ; Se-Ran YANG
International Journal of Stem Cells 2026;19(1):66-82
Idiopathic pulmonary fibrosis (IPF) is characterized by maladaptive epithelial–mesenchymal crosstalk and progressive extracellular matrix accumulation, whereas currently available antifibrotic agents merely decelerate functional decline.This study investigated whether exosomes derived from human mesenchymal stem cells derived from embryonic stem cells (ESC-MSCs) restore epithelial stress responses and attenuate fibrotic remodeling. Human IPF lung transcriptomes were integrated with a bleomycin-induced murine model analyzed by RNA sequencing and protein signaling, together with cigarette smoke extract-induced injury in A549 epithelial cells. ESC-MSCs-derived exosomes exhibited typical morphology and size distribution, enrichment of tetraspanins, and absence of endoplasmic reticulum contamination, consistent with high-purity preparations. Across human IPF and bleomycin-injured lungs, transcriptomic profiling revealed prominent enrichment of extracellular matrix and cytoskeletal gene programs, whereas mitogen-activated protein kinase (MAPK) and Smad families displayed only modest alterations at the mRNA level. In vivo administration of exosomes during the fibrotic remodeling phase, via either intravenous or intratracheal delivery, resulted in improved body weight, reduced lung weight-to-body weight ratios, and decreased collagen deposition and Ashcroft scores. These structural and functional improvements were accompanied by suppression of profibrotic and mesenchymal markers and selective attenuation of activator protein-1 (AP-1) activity. In epithelial injury models, ESC-MSCs-derived exosomes enhanced cell viability, restored redox homeostasis, and constrained stress-induced mesenchymal gene expression and MAPK phosphorylation in both co-treatment and post-treatment settings. Collectively, these data support an epithelial-centered mechanism in which ESC-MSCs-derived exosomes re-establish oxidative balance and selectively restrict AP-1-driven stress signaling, thereby secondarily limiting extracellular matrix accumulation and fibrotic remodeling.
4.Multifactorial Risk Assessment for the Survival of Endodontically Treated Abutments in Removable Partial Dentures: A Retrospective Study
Seo-Yeon LEE ; Jin-Young JANG ; Hye-Jin KIM ; Ran-Ah KIM ; Sun-Ho KIM ; Jeong-Hee KIM
Journal of Korean Dental Science 2026;19(1):23-34
Objective:
This study aimed to evaluate the survival of removable partial dentures (RPDs) abutment teeth that had undergone root canal treatment (RCT) and to identify the factors influencing survival.
Materials and Methods:
Records from the Veterans Health Service Medical Center were reviewed to identify patients who received RPDs between 2014 and 2015 and had root canal-treated abutment teeth. Preoperative variables included patient demographics, tooth location, and periapical radiolucency, while postoperative variables included RPD classification, opposing dentition, crown-root ratio (CRR), root canal filling quality, post placement, and restoration type. Statistical analysis was performed using the Kaplan-Meier method and Cox proportional hazards models.
Results:
A total of 776 root canal-treated abutment teeth from 341 patients using RPDs (mean age, 72.03 years) were included. In the multivariate analysis, tooth-related conditions such as arch type and tooth location, presence of a periapical lesion, and presence of a core were significantly associated with poor prognosis. Kaplan-Meier survival analysis revealed that the 3-, 5-, 7-, and 10-year survival rates for all teeth were 93.5%, 84.4%, 77.1%, and 60.0%, respectively.
Conclusion
Arch type and tooth position, preoperative periapical radiolucency, and type of restoration are significantly associated with prognosis in patients with RPDs in whom the abutment teeth have previously undergone RCT.
5.Relation between pelvic organ prolapse and menopausal hormone therapy: nationwide cohort study
Hee-Yeong JUNG ; Tae-Ran KIM ; Gwan Hee HAN ; Jin-Sung YUK
Obstetrics & Gynecology Science 2025;68(3):210-220
Objective:
To analyze the relationship between pelvic organ prolapse (POP) and menopausal hormone therapy (MHT).
Methods:
This retrospective cohort study used Korean National Health checkup and insurance data from 2002 to 2019. Women who used MHT for more than 6 months between 2002 and 2011 were included in the MHT group; postmenopausal women with no MHT use comprised the non-MHT group.
Results:
In the non-MHT group, there were 1,001,350 women, while the MHT group had 353,206 women. Tibolone (adjusted hazard ratio [aHR], 0.87; 99% confidence interval [CI], 0.818-0.926) and combined estrogen plus progestin by the manufacturer (CEPM) (aHR, 0.821; 99% CI, 0.758-0.89) were associated with reduced POP risk. The other oral MHT groups and the transdermal estrogen group showed no significant difference in POP risk compared with the non-MHT group (other oral MHT: aHR, 1.045; 99% CI, 0.941-1.161) (transdermal estrogen: aHR, 1.252; 99% CI, 0.731-2.145). Lower body mass index (BMI) (<18.5) was associated with reduced POP risk (aHR, 0.822; 99% CI, 0.698-0.968), while a BMI between 23 and 29.9 was associated with increased risk (BMI 23-24.9: aHR, 1.143; 99% CI, 1.088-1.2) (BMI 25-29.9: aHR, 1.173; 99% CI, 1.12-1.228). All parities had a higher POP risk than parity 1 (parity 0 or no response: aHR, 1.785; 99% CI, 1.589-2.005; parity 2: aHR, 1.434; 99% CI, 1.292-1.592; parity ≥3: aHR, 1.916; 99% CI, 1.712-2.144).
Conclusion
Tibolone and CEPM use were associated with reduced POP risk in postmenopausal women. Other MHT types showed no significant association with POP.
6.Risk Factors for Perforation in Endoscopic Treatment for Early Colorectal Cancer: A Nationwide ENTER-K Study
Ik Hyun JO ; Hyun Gun KIM ; Young-Seok CHO ; Hyun Jung LEE ; Eun Ran KIM ; Yoo Jin LEE ; Sung Wook HWANG ; Kyeong-Ok KIM ; Jun LEE ; Hyuk Soon CHOI ; Yunho JUNG ; Chang Mo MOON
Gut and Liver 2025;19(1):95-107
Background/Aims:
Early colorectal cancer (ECC) is commonly resected endoscopically. Perforation is a devastating complication of endoscopic resection. We aimed to identify the characteristics and predictive risk factors for perforation related to endoscopic resection of ECC.
Methods:
This nationwide retrospective multicenter study included patients with ECC who underwent endoscopic resection. We investigated the demographics, endoscopic findings at the time of treatment, and histopathological characteristics of the resected specimens. Logistic regression analysis was used to investigate the clinical factors associated with procedure-related perforations. Survival analysis was conducted to assess the impact of perforation on the overall survival of patients with ECC.
Results:
This study included 965 participants with a mean age of 63.4 years. The most common endoscopic treatment was conventional endoscopic mucosal resection (n=573, 59.4%), followed by conventional endoscopic submucosal dissection (n=259, 26.8%). Thirty-three patients (3.4%) experienced perforations, most of which were managed endoscopically (n=23/33, 69.7%). Patients who undergo endoscopic submucosal dissection-hybrid and precut endoscopic mucosal resection have a higher risk of perforation than those who undergo conventional endoscopic mucosal resection (odds ratio, 78.65 and 39.72, p<0.05). Procedure-related perforations were not associated with patient survival.
Conclusions
Perforation after endoscopic resection had no significant impact on the prognosis of ECC. The type of endoscopic resection was a crucial predictor of perforation. Large-scale prospective studies are needed to further investigate endoscopic resection of ECC.
7.Non-invasive procedure implementation for enhanced smile facial muscle movement after orthognathic surgery: a case report
Su-Jeong KIM ; Soo-Bin KIM ; Yu-Ran HEO ; Hee-Jin KIM
Anatomy & Cell Biology 2025;58(1):136-139
This study examined the case of 27-year-old female who underwent orthognathic surgery to correct class 3 malocclusion, resulting in an unnatural smile. The research aimed to assess the efficacy of non-invasive treatment in enhancing facial muscle movement during smiling to achieve a natural smile. The patient received eight sessions of treatment using non-invasive devices, and facial assessment were conducted using three-dimensional scanner (Morpheus 3D Scanner) to evaluate facial features in both relaxed and maximum smile states pre- and post-treatment. The results demonstrated improvements in the symmetry of the lower lip height during smiling, along with increases in mouth width and volume in the upper central area. Subjectively, the patient also reported enhanced comfort while smiling. These findings suggest that non-invasive procedures can effectively improve unnatural smiles following orthognathic surgery, contributing to a more aesthetically pleasing smile presentation.
8.Non-invasive procedure implementation for enhanced smile facial muscle movement after orthognathic surgery: a case report
Su-Jeong KIM ; Soo-Bin KIM ; Yu-Ran HEO ; Hee-Jin KIM
Anatomy & Cell Biology 2025;58(1):136-139
This study examined the case of 27-year-old female who underwent orthognathic surgery to correct class 3 malocclusion, resulting in an unnatural smile. The research aimed to assess the efficacy of non-invasive treatment in enhancing facial muscle movement during smiling to achieve a natural smile. The patient received eight sessions of treatment using non-invasive devices, and facial assessment were conducted using three-dimensional scanner (Morpheus 3D Scanner) to evaluate facial features in both relaxed and maximum smile states pre- and post-treatment. The results demonstrated improvements in the symmetry of the lower lip height during smiling, along with increases in mouth width and volume in the upper central area. Subjectively, the patient also reported enhanced comfort while smiling. These findings suggest that non-invasive procedures can effectively improve unnatural smiles following orthognathic surgery, contributing to a more aesthetically pleasing smile presentation.
9.Non-invasive procedure implementation for enhanced smile facial muscle movement after orthognathic surgery: a case report
Su-Jeong KIM ; Soo-Bin KIM ; Yu-Ran HEO ; Hee-Jin KIM
Anatomy & Cell Biology 2025;58(1):136-139
This study examined the case of 27-year-old female who underwent orthognathic surgery to correct class 3 malocclusion, resulting in an unnatural smile. The research aimed to assess the efficacy of non-invasive treatment in enhancing facial muscle movement during smiling to achieve a natural smile. The patient received eight sessions of treatment using non-invasive devices, and facial assessment were conducted using three-dimensional scanner (Morpheus 3D Scanner) to evaluate facial features in both relaxed and maximum smile states pre- and post-treatment. The results demonstrated improvements in the symmetry of the lower lip height during smiling, along with increases in mouth width and volume in the upper central area. Subjectively, the patient also reported enhanced comfort while smiling. These findings suggest that non-invasive procedures can effectively improve unnatural smiles following orthognathic surgery, contributing to a more aesthetically pleasing smile presentation.
10.Non-invasive procedure implementation for enhanced smile facial muscle movement after orthognathic surgery: a case report
Su-Jeong KIM ; Soo-Bin KIM ; Yu-Ran HEO ; Hee-Jin KIM
Anatomy & Cell Biology 2025;58(1):136-139
This study examined the case of 27-year-old female who underwent orthognathic surgery to correct class 3 malocclusion, resulting in an unnatural smile. The research aimed to assess the efficacy of non-invasive treatment in enhancing facial muscle movement during smiling to achieve a natural smile. The patient received eight sessions of treatment using non-invasive devices, and facial assessment were conducted using three-dimensional scanner (Morpheus 3D Scanner) to evaluate facial features in both relaxed and maximum smile states pre- and post-treatment. The results demonstrated improvements in the symmetry of the lower lip height during smiling, along with increases in mouth width and volume in the upper central area. Subjectively, the patient also reported enhanced comfort while smiling. These findings suggest that non-invasive procedures can effectively improve unnatural smiles following orthognathic surgery, contributing to a more aesthetically pleasing smile presentation.

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