1.Reinfection of SARS-CoV-2 Variants in Immunocompromised Patients with Prolonged or Relapsed Viral Shedding
Ji Yeun KIM ; Euijin CHANG ; Hyeon Mu JANG ; Jun Ho CHA ; Ju Yeon SON ; Choi Young JANG ; Jeong-Sun YANG ; Joo-Yeon LEE ; Sung-Han KIM
Infection and Chemotherapy 2025;57(1):81-92
Background:
Immunocompromised patients with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection often have prolonged viral shedding, and some are clinically suspected of reinfection with different SARSCoV-2 variants. However, data on this issue are limited. This study investigated the SARS-CoV-2 variants in serially collected respiratory samples from immunocompromised patients with prolonged viral shedding for over 12 weeks or relapsed viral shedding after at least 2 weeks of viral clearance.
Materials and Methods:
From February 2022 to September 2023, we prospectively enrolled immunocompromised patients with coronavirus disease 2019 who had hematologic malignancies or had undergone transplantation and were admitted to a tertiary hospital. Weekly saliva or nasopharyngeal swabs were collected from enrolled patients for at least 12 weeks after diagnosis. Genomic RNA polymerase chain reaction (PCR) was performed on samples, and those testing positive underwent viral culture to isolate the live virus. Spike gene full sequencing via Sanger sequencing and real-time reverse transcription-PCR for detecting mutation genes were conducted to identify SARSCoV-2 variants.
Results:
Among 116 enrolled patients, 20 with prolonged or relapsed viral shedding were screened to identify the variants. Of these 20 patients, 7 (35%) exhibited evidence of re-infection; one of 8 patients with prolonged viral shedding and 6 of 12 with relapsed viral shedding were reinfected with SARS-CoV-2.
Conclusion
Our data suggest that approximately one-third of immunocompromised patients with persistent or relapsed viral shedding had reinfection with different variants of SARS-CoV-2.
2.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.
3.Newly designed flared-end covered versus uncovered self-expandable metallic stents for palliation of malignant colorectal obstruction: a randomized, prospective study
Soo Jung PARK ; Yehyun PARK ; Hyun Jung LEE ; Jae Jun PARK ; Jae Hee CHEON ; Won Ho KIM ; Tae Il KIM
Intestinal Research 2025;23(2):202-212
Background/Aims:
Self-expandable metallic stents (SEMSs) are widely used as palliative or bridge to surgery treatments in patients with malignant colorectal obstruction (MCO). Stent occlusion is more common with uncovered stents, but stent migration is more common with covered stents. Our purpose was to compare the efficacy and safety of a newly designed covered SEMS with an uncovered proximal flared end (CSEMS-UPF) with that of the conventional uncovered SEMS (UCSEMS) in the treatment of MCO.
Methods:
This prospective randomized trial was conducted at a tertiary-care academic hospital. We enrolled 87 patients with stage 4 cancer and MCO: colorectal cancer in 60 patients and extracolonic cancer in 27 patients. Insertion of UCSEMS was randomly assigned to 43 patients, and 44 patients received the CSEMS-UPF. The primary outcome was the duration of stent patency after successful placement. The secondary outcomes were the number of patients with technical and clinical success and early and late complications from the stent insertion.
Results:
The median patency of the stent did not differ between the UCSEMS and CSEMS-UPF groups (484 [231–737] days vs. 216 [66–366] days, P= 0.242). The technical and clinical success rates did not differ significantly between the groups, either (100.0% vs. 93.2%, respectively, P= 0.241; 100.0% vs. 92.7%, respectively, P= 0.112), nor did the early (n = 2 [4.7%] vs. n = 4 [9.8%], P> 0.999) or late (n = 12 [27.9%] vs. n = 15 [36.6%], P> 0.999) stent complication rates differ between the groups.
Conclusions
The UCSEMS and newly developed CSEMS-UPF are similarly effective treatments for MCO, with no differences in the stent migration or occlusion rates (Clinical trial registration number: NCT02640781).
4.Functional Near-Infrared Spectroscopy Analysis of the Cognitive Functions of Elderly Patients With Hearing Loss
Seung Jae LEE ; Jiwon CHOI ; Hyun Bok SONG ; Jeong-Sug KYONG ; Sang-Yeon LEE ; Jun Ho LEE
Journal of Audiology & Otology 2025;29(1):38-48
Background and Objectives:
Age-related hearing loss is a modifiable risk factor for mild cognitive impairment (MCI); however, the potential mechanisms linking these conditions remain unclear. Therefore, in this study, we analyzed the cognitive function profiles of elderly patients with hearing loss via functional near-infrared spectroscopy (fNIRS) to determine the cortical activity differences between patients at risk of MCI and those with normal cognition.
Materials and Methods:
Sixty-three elderly patients with bilateral, moderate, or severe hearing loss were prospectively recruited for this study. Their demographic information was obtained, and audiological evaluations and cognitive function tests were performed. Various instruments were used to assess the cognitive and depression domains. Additionally, fNIRS was used to image the brains of the normal group and group at risk of MCI.
Results:
fNIRS analysis of individual cognitive task data revealed that the normal group exhibited significantly higher oxygenated hemoglobin (HbO2) levels in all cognitive function tasks, except the Stroop color and word test, than the group at risk of MCI. Detailed comparisons of the Brodmann areas revealed that, compared to the group at risk of MCI, normal group exhibited significantly higher HbO2 levels in the right and left dorsolateral prefrontal cortices, ventrolateral prefrontal cortex, frontopolar cortex, and orbitofrontal cortex in the J1 task, right ventrolateral prefrontal cortex in the J2 task, and right orbitofrontal cortex in the J6 task.
Conclusions
Measurement of fNIRS signals in the frontal lobes revealed different HbO2 signals between the normal group and group at risk of MCI during minimal hearing loss. Future studies should explore the causal link between hearing loss and cognitive impairment by analyzing the changes in cognitive function after auditory rehabilitation.
5.Stiffness-Related Disability Following Surgical Correction for Adolescent Idiopathic Scoliosis:A Comparative Analysis According to the Lowest Instrumented Vertebra Level
Se-Jun PARK ; Chong-Suh LEE ; Dong-Ho KANG ; Jin-Sung PARK
Clinics in Orthopedic Surgery 2025;17(2):258-266
Background:
Extensive spinal fusion inevitably results in loss of mobility, which may induce stiffness-related disability (SRD) during activities of daily living. Few studies have examined SRD after surgical correction for adolescent idiopathic scoliosis (AIS). This study aimed to investigate SRD following surgical treatment in AIS patients particularly with respect to the lowest instrumented vertebra (LIV).
Methods:
Patients who underwent surgical correction for AIS between 2014 and 2021 and were followed up for 2 years were included. The degree of SRD was evaluated using the Stiffness-Related Disability Index (SRDI), which consists of 4 categories, each containing 3 questions, giving a total of 12 components of the questionnaire. The SRDI scores were compared according to the LIV level. Correlation analysis was performed to examine the relationship between the SRDI and legacy health-related quality of life (HRQOL) measurements.
Results:
This study included 174 patients (47 men and 127 women) with a mean age of 13.8 years. Among the 12 items of the SRDI, the scores of 9 items showed a significant increase after surgery. The total sum of the SRDI scores also significantly increased after surgery. Pearson correlation analysis showed that the SRDI scores were significantly correlated with Oswestry disability index, nearly all domains, and the total sum of Scoliosis Research Society-22 questionnaire, and 36-Item Short Form Survey.No differences in the SRDI score were found among cases with the LIV between T12 and L3. However, the SRDI scores of patients with LIV at L4 were significantly higher than those of patients with other LIV levels.
Conclusions
Various degrees of SRD occurred after spinal fusion for AIS. The SRDI was significantly correlated with the HRQOL measurements. The SRDI score was highest in patients with the LIV at L4 when compared to those with other LIV levels. Fusion can be safely extended to L3 without significantly increasing SRD.
6.Comparing Stability, Gait, and Functional Score after 40-mm Dual-Mobility Hip Arthroplasty to 36-mm Head Hip Arthroplasty in Elderly Hip Fracture Patients
Yonghan CHA ; Sang-Yeob LEE ; Ji-Ho BAE ; Yang Jae KANG ; Ji-Hoon BAEK ; Joon Soon KANG ; Chan Ho PARK ; Shinjune KIM ; Jun-Il YOO
Clinics in Orthopedic Surgery 2025;17(1):62-70
Background:
This study aimed to compare the intraoperative stability and early clinical outcomes of 40-mm diameter dual mobility (DM)-total hip arthroplasty (THA) with 36-mm ceramic head (large head) THA in active elderly patients with hip fractures.
Methods:
A prospective randomized controlled trial was conducted from May 2022 to December 2022. Inclusion criteria were as follows: age ≥ 60 years, displaced femoral neck fracture, Koval grade 1 or 2, planned 54-mm acetabular component, and over 1-year follow-up. Intraoperative stability tests were performed on all patients (internal rotation at 45°, 60°, and 90° of hip fracture). Functional outcomes (Harris Hip Score and University of California, Los Angeles [UCLA] Score) were evaluated at 6 weeks and 3 months postoperatively. Gait analysis using artificial intelligence (AI) techniques was conducted at 3 months postoperatively.
Results:
The study included 36 DM-THA patients (mean age, 69.6 ± 2.2 years; 44% women) and 37 large head THA patients (mean age, 69.6 ± 1.2 years; 64% women). No statistically significant differences were observed in functional outcomes and hip range of motion between the 2 groups. However, there was a significant difference in the gait speed and stance-swing phase of the large head THA group and the DM-THA group: the DM-THA group demonstrated superior gait speed (2.85 ± 0.83 kph vs. 2.04 ± 1.04 kph, p = 0.003) and higher stance phase ratios (operated side: 63.57% ± 3.82% vs. 48.19% ± 5.50%, p < 0.001; opposite side: 62.77% ± 2.27% vs. 49.93% ± 6.94%, p < 0.001). In the stability test at 90° of hip flexion, the DM-THA group had a measurement of 48.40° ± 5.17°, while the large head THA group had a measurement of 30.94° ± 2.98° (p = 0.012). Despite the lack of statistical significance, the intraoperative stability test showed the dislocation angle was notably different between the groups in the hip flexion position of 60° (51.60° ± 6.09° in the DM-THA group and 40.00° ± 2.80° in the large head THA group, p = 0.072).
Conclusions
Superior results were observed in the intraoperative stability test and early recovery of gait after DM-THA compared to large head THA. We believe that DM-THA can be a useful surgical option for THA in elderly patients with hip fractures.
7.Knee Morphology and Proximal Tibial Bone Quality around the Posterior Cruciate Ligament Insertion Site Affect Injury Patterns
Young Tak CHO ; Jong Hwa LEE ; Jun Hyeok YOON ; Seok Ho HONG ; Joong Il KIM
Clinics in Orthopedic Surgery 2025;17(3):400-407
Background:
Several studies have investigated the morphological risk factors contributing to posterior cruciate ligament (PCL) injury. However, no study has focused on the injury patterns of intrasubstance tears or tibial avulsion fractures in relation to morphologies and regional bone quality. This study aimed to investigate the impact of the knee morphology and regional bone quality of the proximal tibia on the PCL injury pattern.
Methods:
This retrospective study compared the radiological features of 76 patients with PCL injuries (PI group) and 76 matched patients with normal PCL (control group). The PI group was divided into 2 subgroups: PCL avulsion fracture (PAF subgroup; n = 43) and PCL intrasubstance tear (PIT subgroup; n = 33). Measurements included the coronal notch width index, coronal tibial slope, medial and lateral posterior tibial slopes, and medial tibial depth. Three Hounsfield unit average measurements were taken from the proximal tibia around the PCL insertion site to create a summative measure of overall bone quality.
Results:
The medial tibial depth and coronal notch width index were significantly lower in the PI group than those in the control group (medial tibial depth: 2.04 ± 0.77 vs. 3.02 ± 1.04, p = 0.017; coronal notch width index: 0.21 ± 0.03 vs. 0.24 ± 0.03, p = 0.041). In the subgroup analysis, medial tibial depth and Hounsfield unit were significantly lower in the PAF subgroup than in the PIT subgroup (medial tibial depth: 1.74 ± 0.66 vs. 2.43 ± 0.77, p = 0.008, Hounsfield unit: 89.48 ± 31.73 vs. 120.15 ± 29.24, p = 0.004). Binary logistic regression analysis showed that medial tibial depth (odds ratio [OR], 0.161; p < 0.001) and Hounsfield unit (OR, 0.950;p < 0.001) were independent risk factors for PCL tibial avulsion fractures.
Conclusions
Lower notch width index and medial tibial depth are associated with PCL injuries. Shallower medial tibial depth and lower Hounsfield unit measurements around the PCL insertion site were associated with an increased incidence of PCL avulsion fractures. These findings may assist clinicians in identifying patients at risk of distinct PCL injury patterns.
8.Deep Learning Technology for Classification of Thyroid Nodules Using Multi-View Ultrasound Images: Potential Benefits and Challenges in Clinical Application
Jinyoung KIM ; Min-Hee KIM ; Dong-Jun LIM ; Hankyeol LEE ; Jae Jun LEE ; Hyuk-Sang KWON ; Mee Kyoung KIM ; Ki-Ho SONG ; Tae-Jung KIM ; So Lyung JUNG ; Yong Oh LEE ; Ki-Hyun BAEK
Endocrinology and Metabolism 2025;40(2):216-224
Background:
This study aimed to evaluate the applicability of deep learning technology to thyroid ultrasound images for classification of thyroid nodules.
Methods:
This retrospective analysis included ultrasound images of patients with thyroid nodules investigated by fine-needle aspiration at the thyroid clinic of a single center from April 2010 to September 2012. Thyroid nodules with cytopathologic results of Bethesda category V (suspicious for malignancy) or VI (malignant) were defined as thyroid cancer. Multiple deep learning algorithms based on convolutional neural networks (CNNs) —ResNet, DenseNet, and EfficientNet—were utilized, and Siamese neural networks facilitated multi-view analysis of paired transverse and longitudinal ultrasound images.
Results:
Among 1,048 analyzed thyroid nodules from 943 patients, 306 (29%) were identified as thyroid cancer. In a subgroup analysis of transverse and longitudinal images, longitudinal images showed superior prediction ability. Multi-view modeling, based on paired transverse and longitudinal images, significantly improved the model performance; with an accuracy of 0.82 (95% confidence intervals [CI], 0.80 to 0.86) with ResNet50, 0.83 (95% CI, 0.83 to 0.88) with DenseNet201, and 0.81 (95% CI, 0.79 to 0.84) with EfficientNetv2_ s. Training with high-resolution images obtained using the latest equipment tended to improve model performance in association with increased sensitivity.
Conclusion
CNN algorithms applied to ultrasound images demonstrated substantial accuracy in thyroid nodule classification, indicating their potential as valuable tools for diagnosing thyroid cancer. However, in real-world clinical settings, it is important to aware that model performance may vary depending on the quality of images acquired by different physicians and imaging devices.
9.A comparison of the outcomes of families with children aged less than 2 who received universal versus sustained nurse home visiting services in Korea: a cross-sectional study
Yu-Mi KIM ; Sun Hwa PARK ; Kyung Ja JUNE ; Sung-Hyun CHO ; Ji Yun LEE ; Hong-Jun CHO ; Young-Ho KHANG
Epidemiology and Health 2025;47(1):e2025004-
OBJECTIVES:
This study aimed to compare maternal outcomes and the home environment between non‑vulnerable families with children under 2 receiving universal home visiting services and vulnerable families receiving sustained home visiting services.
METHODS:
This study was conducted in Seoul, Korea, where the country’s first nurse‑led early childhood home visiting program was introduced. A total of 551 mother‑child dyads participated in cross‑sectional surveys conducted at various child ages (6±2 weeks, 6±1 months, 12±1 months, and 24±1 months). Universal home visiting services were provided within six weeks postpartum to non‑vulnerable families, while vulnerable families received sustained services consisting of 25 visits over 24 months. Maternal knowledge of sudden infant death syndrome (SIDS) and childcare, maternal distress, and the Korean Infant‑Toddler Home Observation for Measurement of Environment (K‑IT‑HOME) were assessed.
RESULTS:
Overall, the universal home visitation group demonstrated higher levels of maternal knowledge regarding SIDS and childcare compared to the sustained home visitation group (all p-values <0.05), while the sustained home visitation group reported higher levels of maternal distress (p<0.001). The total K‑IT‑HOME score was 1.47 points higher in the universal home visitation group than in the sustained home visitation group (p<0.001). No significant differences were observed in the acceptance, organization, or involvement subscales of the K‑IT‑HOME (all p-values >0.05).
CONCLUSIONS
This study demonstrated that disparities in maternal outcomes and home environments persisted in early childhood between the sustained and universal home visitation groups.
10.Combination of Aβ40, Aβ42, and Tau Plasma Levels to Distinguish Amyloid-PET Positive Alzheimer Patients from Normal Controls
Seungyeop BAEK ; Jinny Claire LEE ; Byung Hyun BYUN ; Su Yeon PARK ; Jeong Ho HA ; Kyo Chul LEE ; Seung-Hoon YANG ; Jun-Seok LEE ; Seungpyo HONG ; Gyoonhee HAN ; Sang Moo LIM ; YoungSoo KIM ; Hye Yun KIM
Experimental Neurobiology 2025;34(1):1-8
Alzheimer disease (AD) diagnosis is confirmed using a medley of modalities, such as the detection of amyloid-β (Aβ) neuritic plaques and neurofibrillary tangles with positron electron tomography (PET) or the appraisal of irregularities in cognitive function with examinations. Although these methods have been efficient in confirming AD pathology, the rising demand for earlier intervention during pathogenesis has led researchers to explore the diagnostic potential of fluid biomarkers in cerebrospinal fluid (CSF) and plasma. Since CSF sample collection is invasive and limited in quantity, biomarker detection in plasma has become more attractive and modern advancements in technology has permitted more efficient and accurate analysis of plasma biomolecules. In this study, we found that a composite of standard factors, Aβ40 and total tau levels in plasma, divided by the variation factor, plasma Aβ42 level, provide better correlation with amyloid neuroimaging and neuropsychological test results than a level comparison between total tau and Aβ42 in plasma. We collected EDTA-treated blood plasma samples of 53 subjects, of randomly selected 27 AD patients and 26 normal cognition (NC) individuals, who received amyloid-PET scans for plaque quantification, and measured plasma levels of Aβ40, Aβ42, and total tau with digital enzyme-linked immunosorbent assay (ELISA) in a blinded manner. There was difficulty distinguishing AD patients from controls when analyzing biomarkers independently. However, significant differentiation was observed between the two groups when comparing individual ratios of total-tau×Aβ40/Aβ42. Our results indicate that collectively comparing fluctuations of these fluid biomarkers could aid in monitoring AD pathogenesis.

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