1.Mock communities to assess biases in nextgeneration sequencing of bacterial species representation
Younjee HWANG ; Ju Yeong KIM ; Se Il KIM ; Ji Yeon SUNG ; Hye Su MOON ; Tai-Soon YONG ; Ki Ho HONG ; Hyukmin LEE ; Dongeun YONG
Annals of Clinical Microbiology 2025;28(1):3-
Background:
The 16S rRNA-targeted next-generation sequencing (NGS) has been widely used as the primary tool for microbiome analysis. However, whether the sequenced microbial diversity absolutely represents the original sample composition remains unclear. This study aimed to evaluate whether 16S rRNA gene-targeted NGS accurately captures bacterial community composition.
Methods:
Mock communities were constructed using equal amounts of DNA from 18 bacterial strains in three formats: genomic DNA, recombinant plasmids, and polymerase chain reaction (PCR) templates. The V3V4 region of the 16S rRNA gene was amplified and sequenced using the Illumina MiSeq.
Results:
Data regression analysis revealed that the recombinant plasmid produced more accurate and precise correlation curve than that by the gDNA and PCR products, with a slope closest to 1 (1.0082) and the highest R² value (0.9975). Despite the same input amount of bacterial DNA, the NGS read distribution varied across all three mock communities. Using multiple regression analysis, we found that the guanine-cytosine (GC) content of the V3V4 region, 16S rRNA gene, size of gDNA, and copy number of 16S rRNA were significantly associated with the NGS output of each bacterial species.
Conclusion
This study demonstrated that recombinant plasmids are the preferred option for quality control and that NGS output is biased owing to certain bacterial characteristics, such as %GC content, gDNA size, and 16S rRNA gene copy number. Further research is required to develop a system that compensates for NGS process biases using mock communities.
2.Mock communities to assess biases in nextgeneration sequencing of bacterial species representation
Younjee HWANG ; Ju Yeong KIM ; Se Il KIM ; Ji Yeon SUNG ; Hye Su MOON ; Tai-Soon YONG ; Ki Ho HONG ; Hyukmin LEE ; Dongeun YONG
Annals of Clinical Microbiology 2025;28(1):3-
Background:
The 16S rRNA-targeted next-generation sequencing (NGS) has been widely used as the primary tool for microbiome analysis. However, whether the sequenced microbial diversity absolutely represents the original sample composition remains unclear. This study aimed to evaluate whether 16S rRNA gene-targeted NGS accurately captures bacterial community composition.
Methods:
Mock communities were constructed using equal amounts of DNA from 18 bacterial strains in three formats: genomic DNA, recombinant plasmids, and polymerase chain reaction (PCR) templates. The V3V4 region of the 16S rRNA gene was amplified and sequenced using the Illumina MiSeq.
Results:
Data regression analysis revealed that the recombinant plasmid produced more accurate and precise correlation curve than that by the gDNA and PCR products, with a slope closest to 1 (1.0082) and the highest R² value (0.9975). Despite the same input amount of bacterial DNA, the NGS read distribution varied across all three mock communities. Using multiple regression analysis, we found that the guanine-cytosine (GC) content of the V3V4 region, 16S rRNA gene, size of gDNA, and copy number of 16S rRNA were significantly associated with the NGS output of each bacterial species.
Conclusion
This study demonstrated that recombinant plasmids are the preferred option for quality control and that NGS output is biased owing to certain bacterial characteristics, such as %GC content, gDNA size, and 16S rRNA gene copy number. Further research is required to develop a system that compensates for NGS process biases using mock communities.
3.Small-bowel bezoars in an infant following synbiotic ingestion: a novel case report
Pediatric Emergency Medicine Journal 2025;12(2):78-82
Bezoars in infants are rare owing to their limited dietary diversity. This report presents a novel case of multiple phytobezoars in the small bowel of a 3-month-old boy following ingestion of a synbiotic, a nutritional supplement combining probiotics (bacteria) and prebiotics (fibers that promote bacterial growth), which required a surgical intervention. Given the increasing use of synbiotics, the possibility of such bezoar formation should be considered, particularly in infants with underlying risk factors, such as congenital aganglionic megacolon.
4.Effects of Methylphenidate and Atomoxetine Treatment on Improvement of Motor Coordination in Children With Attention-Deficit/Hyperactivity Disorder
Ju Yeon KIM ; Eunji JUNG ; Taeyeop LEE ; Kee Jeong PARK ; Yoo-Sook JOUNG ; Hyo-Won KIM
Psychiatry Investigation 2025;22(1):84-92
Objective:
To investigate the effects of methylphenidate and atomoxetine treatment on motor coordination in children with attention-deficit/hyperactivity disorder (ADHD).
Methods:
In this single-site, open-label, naturalistic follow-up study, 157 children (7.6±1.4 years; 139 males) with ADHD were recruited between March 2015 and May 2020 from the Department of Psychiatry, Asan Medical Center, and treated for 12 weeks with methylphenidate (n=48) or atomoxetine (n=109). Children completed the Advanced Test of Attention (ATA), and caregivers completed the ADHD Rating Scale (ARS) questionnaire and Developmental Coordination Disorder Questionnaire (DCDQ) at baseline and at 12 weeks. Paired t-tests, a mixed-effects model, and linear regression were used to compare treatment groups and assess factors influencing motor coordination changes.
Results:
Methylphenidate and atomoxetine resulted in significant improvement in DCDQ fine motor/handwriting, general coordination, and total scores over 12 weeks. Fine motor/handwriting had a significant main effect for time (F1=16.64, p<0.001, η2=0.097); however, the interaction effect between group and time was not significant (F1=0.24, p=0.625, η2=0.002). Changes in parent-reported ARS inattention scores (β=-0.174, p=0.029) and auditory commission errors of ATA (β=0.191, p=0.022) were significantly associated with changes in fine motor/handwriting. Additionally, changes in parent-reported ARS inattention scores (β=-0.177, p=0.034) and rater-reported ARS inattention scores (β=-0.198, p=0.017) were significant predictors of improvements in general coordination in separate models.
Conclusion
Methylphenidate and atomoxetine had a positive effect on motor coordination in children with ADHD. Improvement in motor coordination was associated with ADHD symptom improvement.
5.The Role of Knowledge and Personal Experience in Shaping Stigma Associated With COVID-19 and Mental Illness
Ji-Min YOO ; Ju-Wan KIM ; Seon-Young KIM ; Seunghyong RYU ; Ju-Yeon LEE ; Sook-In JUNG ; Jae-Min KIM ; Sung-Wan KIM
Psychiatry Investigation 2025;22(1):110-116
Objective:
Stigma influences perceptions of mental illness and novel diseases like coronavirus disease-2019 (COVID-19), often impeding healthcare access despite advancements in medical treatment. This study compares the stigma associated with COVID-19 and mental illness to identify factors that could help reduce stigma.
Methods:
An online survey was conducted in May 2023 among 1,500 participants aged 19 to 65 in South Korea, using a panel from Embrain, an online survey service. The survey assessed stigma and distress related to COVID-19 and mental illness using a validated questionnaire. It collected demographic and clinical data, evaluated COVID-19-related stigma, fear, and knowledge, and measured prejudice and attitudes toward psychiatric treatment. Personality traits were assessed using the Big Five Inventory (BFI)-10. Factors significantly associated with stigma scores were entered into linear regression analysis.
Results:
COVID-19-related stigma scores were significantly negatively correlated with knowledge of COVID-19 and positively correlated with fear of infection and age. Individuals with a history of COVID-19 infection had significantly lower scores on COVID-19-related stigma. Similarly, mental illness stigma was negatively correlated with knowledge of psychiatric treatment and positively correlated with age, as well as conscientiousness and neuroticism in the BFI. Personal experience with individuals with mental illness was associated with significantly lower stigma scores.
Conclusion
This study suggests that the mechanism-making stigma was similar in cases of traditional mental illness and a novel infectious disease. Both cognitive and experiential factors influence stigma. Educating the public about the disease and enabling interactions with affected individuals emerge as effective strategies for stigma reduction.
6.A Novel Histone Deacetylase 6 Inhibitor, 4-FHA, Improves Scopolamine-Induced Cognitive and Memory Impairment in Mice
Jee-Yeon SEO ; Jisoo KIM ; Yong-Hyun KO ; Bo-Ram LEE ; Kwang-Hyun HUR ; Young Hoon JUNG ; Hyun-Ju PARK ; Seok-Yong LEE ; Choon-Gon JANG
Biomolecules & Therapeutics 2025;33(2):268-277
Although histone deacetylase 6 (HDAC6) is considered a therapeutic target for Alzheimer’s disease (AD), its role in cholinergic dysfunction in AD patients remains unclear. This study investigated the effects of (E)-3-(2-(4-fluorostyryl)thiazol-4-yl)-N-hydroxypropanamide (4-FHA), a new synthetic HDAC6 inhibitor, on cognitive and memory impairments in a scopolamine-induced-AD mouse model. Behaviorally, 4-FHA improved scopolamine-induced memory impairments in the Y-maze, passive avoidance, and Morris water maze tests. In addition, 4-FHA ameliorated scopolamine-induced cognitive impairments in the novel object recognition and place recognition tests. Furthermore, 4-FHA increased acetylation of α-tubulin (a major HDAC6 substrate); the expression of BDNF; and the phosphorylation of ERK 1/2, CREB, and ChAT in the hippocampus of scopolamine-treated mice. In summary, according to our data 4-FHA, an HDAC6 inhibitor, improved the cognitive and memory deficits of the AD mouse model by normalizing BDNF signaling and synaptic transmission, suggesting that 4-FHA might be a potential therapeutic candidate for AD.
7.Target-Enhanced Whole-Genome Sequencing Shows Clinical Validity Equivalent to Commercially Available Targeted Oncology Panel
Sangmoon LEE ; Jin ROH ; Jun Sung PARK ; Islam Oguz TUNCAY ; Wonchul LEE ; Jung-Ah KIM ; Brian Baek-Lok OH ; Jong-Yeon SHIN ; Jeong Seok LEE ; Young Seok JU ; Ryul KIM ; Seongyeol PARK ; Jaemo KOO ; Hansol PARK ; Joonoh LIM ; Erin CONNOLLY-STRONG ; Tae-Hwan KIM ; Yong Won CHOI ; Mi Sun AHN ; Hyun Woo LEE ; Seokhwi KIM ; Jang-Hee KIM ; Minsuk KWON
Cancer Research and Treatment 2025;57(2):350-361
Purpose:
Cancer poses a significant global health challenge, demanding precise genomic testing for individualized treatment strategies. Targeted-panel sequencing (TPS) has improved personalized oncology but often lacks comprehensive coverage of crucial cancer alterations. Whole-genome sequencing (WGS) addresses this gap, offering extensive genomic testing. This study demonstrates the medical potential of WGS.
Materials and Methods:
This study evaluates target-enhanced WGS (TE-WGS), a clinical-grade WGS method sequencing both cancer and matched normal tissues. Forty-nine patients with various solid cancer types underwent both TE-WGS and TruSight Oncology 500 (TSO500), one of the mainstream TPS approaches.
Results:
TE-WGS detected all variants reported by TSO500 (100%, 498/498). A high correlation in variant allele fractions was observed between TE-WGS and TSO500 (r=0.978). Notably, 223 variants (44.8%) within the common set were discerned exclusively by TE-WGS in peripheral blood, suggesting their germline origin. Conversely, the remaining subset of 275 variants (55.2%) were not detected in peripheral blood using the TE-WGS, signifying them as bona fide somatic variants. Further, TE-WGS provided accurate copy number profiles, fusion genes, microsatellite instability, and homologous recombination deficiency scores, which were essential for clinical decision-making.
Conclusion
TE-WGS is a comprehensive approach in personalized oncology, matching TSO500’s key biomarker detection capabilities. It uniquely identifies germline variants and genomic instability markers, offering additional clinical actions. Its adaptability and cost-effectiveness underscore its clinical utility, making TE-WGS a valuable tool in personalized cancer treatment.
8.Educational Level Modifies the Relationship between Standard Deviation of NN Intervals and Post-traumatic Stress Disorder Development over Two-years
Ji Min YOO ; Ju-Wan KIM ; Hee-Ju KANG ; Hyunseok JANG ; Jung-Chul KIM ; Ju-Yeon LEE ; Sung-Wan KIM ; Il-Seon SHIN ; Jae-Min KIM
Clinical Psychopharmacology and Neuroscience 2025;23(1):155-160
Objective:
This study investigated how educational levels modify the relationship between the standard deviation of NN intervals (SDNN) of heart rate variability and the development of post-traumatic stress disorder (PTSD).
Methods:
Participants with physical injuries were enrolled from a trauma center and monitored over two years. Initial assessments included SDNN and educational attainment, along with socio-demographic and clinical variables. PTSD diagnoses were made at 3, 6, 12, and 24 months post-injury using the Clinician-Administered PTSD Scale for DSM-5.Logistic regression analyses were conducted.
Results:
Of the 538 participants, 58 (10.8%) developed PTSD during the follow-up period. A significant interaction effect was observed: lower SDNN was significantly linked to PTSD in individuals with higher education, but not in those with lower education.
Conclusion
The study identified education-dependent associations between SDNN and PTSD development, emphasizing the importance of tailored PTSD prevention strategies that consider both SDNN and educational levels.
9.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.
10.Evaluating Rituximab Failure Rates in Neuromyelitis Optica Spectrum Disorder: A Nationwide Real-World Study From South Korea
Su-Hyun KIM ; Ju-Hong MIN ; Sung-Min KIM ; Eun-Jae LEE ; Young-Min LIM ; Ha Young SHIN ; Young Nam KWON ; Eunhee SOHN ; Sooyoung KIM ; Min Su PARK ; Tai-Seung NAM ; Byeol-A YOON ; Jong Kuk KIM ; Kyong Jin SHIN ; Yoo Hwan KIM ; Jin Myoung SEOK ; Jeong Bin BONG ; Sohyeon KIM ; Hung Youl SEOK ; Sun-Young OH ; Ohyun KWON ; Sunyoung KIM ; Sukyoon LEE ; Nam-Hee KIM ; Eun Bin CHO ; Sa-Yoon KANG ; Seong-il OH ; Jong Seok BAE ; Suk-Won AHN ; Ki Hoon KIM ; You-Ri KANG ; Woohee JU ; Seung Ho CHOO ; Yeon Hak CHUNG ; Jae-Won HYUN ; Ho Jin KIM
Journal of Clinical Neurology 2025;21(2):131-136
Background:
and Purpose Treatments for neuromyelitis optica spectrum disorder (NMOSD) such as eculizumab, ravulizumab, satralizumab, and inebilizumab have significantly advanced relapse prevention, but they remain expensive. Rituximab is an off-label yet popular alternative that offers a cost-effective solution, but its real-world efficacy needs better quantification for guiding the application of newer approved NMOSD treatments (ANTs). This study aimed to determine real-world rituximab failure rates to anticipate the demand for ANTs and aid in resource allocation.
Methods:
We conducted a nationwide retrospective study involving 605 aquaporin-4-antibody-positive NMOSD patients from 22 centers in South Korea that assessed the efficacy and safety of rituximab over a median follow-up of 47 months.
Results:
The 605 patients treated with rituximab included 525 (87%) who received continuous therapy throughout the follow-up period (median=47 months, interquartile range=15–87 months). During this period, 117 patients (19%) experienced at least 1 relapse. Notably, 68 of these patients (11% of the total cohort) experienced multiple relapses or at least 1 severe relapse.Additionally, 2% of the patients discontinued rituximab due to adverse events, which included severe infusion reactions, neutropenia, and infections.
Conclusions
This study has confirmed the efficacy of rituximab in treating NMOSD, as evidenced by an 87% continuation rate among patients over a 4-year follow-up period. Nevertheless, the occurrence of at least one relapse in 19% of the cohort, including 11% who experienced multiple or severe relapses, and a 2% discontinuation rate due to adverse events highlight the urgent need for alternative therapeutic options.

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