1.Reproducibility of Plasma Biomarker Measurements Across Laboratories:Insights Into ptau217, GFAP, and NfL
Heekyoung KANG ; Sook-Young WOO ; Daeun SHIN ; Sohyun YIM ; Eun Hye LEE ; Hyunchul RYU ; Bora CHU ; Henrik ZETTERBERG ; Kaj BLENNOW ; Jihwan YUN ; Duk L NA ; Hee Jin KIM ; Hyemin JANG ; Jun Pyo KIM ;
Dementia and Neurocognitive Disorders 2025;24(2):91-101
Background:
and Purpose: Plasma biomarkers, including phosphorylated tau (ptau217), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL), are promising tools for detecting Alzheimer’s disease (AD) pathology. However, cross-laboratory reproducibility remains a challenge, even when using identical analytical platforms such as single-molecule array (Simoa). This study aimed to compare plasma biomarker measurements (ptau217, GFAP, and NfL) between 2 laboratories, the University of Gothenburg (UGOT) and DNAlink, and evaluate their associations with amyloid positron emission tomography (PET) imaging.
Methods:
Plasma biomarkers were measured using Simoa platforms at both laboratories:the UGOT and DNAlink Incorporation. Diagnostic performance for predicting amyloid PET positivity, cross-laboratory agreement, and the impact of normalization techniques were assessed. Bland-Altman plots and correlation analyses were employed to evaluate agreement and variability.
Results:
Plasma ptau217 concentrations exhibited strong correlations with amyloid PET global centiloid values, with comparable diagnostic performance between laboratories (area under the curve=0.94 for UGOT and 0.95 for DNAlink). Cross-laboratory agreement for ptau217 was excellent (r=0.96), improving further after natural log transformation. GFAP and NfL also demonstrated moderate to strong correlations (r=0.86 for GFAP and r=0.99 for NfL), with normalization reducing variability.
Conclusions
Plasma biomarker measurements were consistent across laboratories using identical Simoa platforms, with strong diagnostic performance and improved agreement after normalization. These findings support the scalability of plasma biomarkers for multicenter studies and underscore their potential for standardized applications in AD research and clinical practice.
2.Reproducibility of Plasma Biomarker Measurements Across Laboratories:Insights Into ptau217, GFAP, and NfL
Heekyoung KANG ; Sook-Young WOO ; Daeun SHIN ; Sohyun YIM ; Eun Hye LEE ; Hyunchul RYU ; Bora CHU ; Henrik ZETTERBERG ; Kaj BLENNOW ; Jihwan YUN ; Duk L NA ; Hee Jin KIM ; Hyemin JANG ; Jun Pyo KIM ;
Dementia and Neurocognitive Disorders 2025;24(2):91-101
Background:
and Purpose: Plasma biomarkers, including phosphorylated tau (ptau217), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL), are promising tools for detecting Alzheimer’s disease (AD) pathology. However, cross-laboratory reproducibility remains a challenge, even when using identical analytical platforms such as single-molecule array (Simoa). This study aimed to compare plasma biomarker measurements (ptau217, GFAP, and NfL) between 2 laboratories, the University of Gothenburg (UGOT) and DNAlink, and evaluate their associations with amyloid positron emission tomography (PET) imaging.
Methods:
Plasma biomarkers were measured using Simoa platforms at both laboratories:the UGOT and DNAlink Incorporation. Diagnostic performance for predicting amyloid PET positivity, cross-laboratory agreement, and the impact of normalization techniques were assessed. Bland-Altman plots and correlation analyses were employed to evaluate agreement and variability.
Results:
Plasma ptau217 concentrations exhibited strong correlations with amyloid PET global centiloid values, with comparable diagnostic performance between laboratories (area under the curve=0.94 for UGOT and 0.95 for DNAlink). Cross-laboratory agreement for ptau217 was excellent (r=0.96), improving further after natural log transformation. GFAP and NfL also demonstrated moderate to strong correlations (r=0.86 for GFAP and r=0.99 for NfL), with normalization reducing variability.
Conclusions
Plasma biomarker measurements were consistent across laboratories using identical Simoa platforms, with strong diagnostic performance and improved agreement after normalization. These findings support the scalability of plasma biomarkers for multicenter studies and underscore their potential for standardized applications in AD research and clinical practice.
3.Reproducibility of Plasma Biomarker Measurements Across Laboratories:Insights Into ptau217, GFAP, and NfL
Heekyoung KANG ; Sook-Young WOO ; Daeun SHIN ; Sohyun YIM ; Eun Hye LEE ; Hyunchul RYU ; Bora CHU ; Henrik ZETTERBERG ; Kaj BLENNOW ; Jihwan YUN ; Duk L NA ; Hee Jin KIM ; Hyemin JANG ; Jun Pyo KIM ;
Dementia and Neurocognitive Disorders 2025;24(2):91-101
Background:
and Purpose: Plasma biomarkers, including phosphorylated tau (ptau217), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL), are promising tools for detecting Alzheimer’s disease (AD) pathology. However, cross-laboratory reproducibility remains a challenge, even when using identical analytical platforms such as single-molecule array (Simoa). This study aimed to compare plasma biomarker measurements (ptau217, GFAP, and NfL) between 2 laboratories, the University of Gothenburg (UGOT) and DNAlink, and evaluate their associations with amyloid positron emission tomography (PET) imaging.
Methods:
Plasma biomarkers were measured using Simoa platforms at both laboratories:the UGOT and DNAlink Incorporation. Diagnostic performance for predicting amyloid PET positivity, cross-laboratory agreement, and the impact of normalization techniques were assessed. Bland-Altman plots and correlation analyses were employed to evaluate agreement and variability.
Results:
Plasma ptau217 concentrations exhibited strong correlations with amyloid PET global centiloid values, with comparable diagnostic performance between laboratories (area under the curve=0.94 for UGOT and 0.95 for DNAlink). Cross-laboratory agreement for ptau217 was excellent (r=0.96), improving further after natural log transformation. GFAP and NfL also demonstrated moderate to strong correlations (r=0.86 for GFAP and r=0.99 for NfL), with normalization reducing variability.
Conclusions
Plasma biomarker measurements were consistent across laboratories using identical Simoa platforms, with strong diagnostic performance and improved agreement after normalization. These findings support the scalability of plasma biomarkers for multicenter studies and underscore their potential for standardized applications in AD research and clinical practice.
4.Reproducibility of Plasma Biomarker Measurements Across Laboratories:Insights Into ptau217, GFAP, and NfL
Heekyoung KANG ; Sook-Young WOO ; Daeun SHIN ; Sohyun YIM ; Eun Hye LEE ; Hyunchul RYU ; Bora CHU ; Henrik ZETTERBERG ; Kaj BLENNOW ; Jihwan YUN ; Duk L NA ; Hee Jin KIM ; Hyemin JANG ; Jun Pyo KIM ;
Dementia and Neurocognitive Disorders 2025;24(2):91-101
Background:
and Purpose: Plasma biomarkers, including phosphorylated tau (ptau217), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL), are promising tools for detecting Alzheimer’s disease (AD) pathology. However, cross-laboratory reproducibility remains a challenge, even when using identical analytical platforms such as single-molecule array (Simoa). This study aimed to compare plasma biomarker measurements (ptau217, GFAP, and NfL) between 2 laboratories, the University of Gothenburg (UGOT) and DNAlink, and evaluate their associations with amyloid positron emission tomography (PET) imaging.
Methods:
Plasma biomarkers were measured using Simoa platforms at both laboratories:the UGOT and DNAlink Incorporation. Diagnostic performance for predicting amyloid PET positivity, cross-laboratory agreement, and the impact of normalization techniques were assessed. Bland-Altman plots and correlation analyses were employed to evaluate agreement and variability.
Results:
Plasma ptau217 concentrations exhibited strong correlations with amyloid PET global centiloid values, with comparable diagnostic performance between laboratories (area under the curve=0.94 for UGOT and 0.95 for DNAlink). Cross-laboratory agreement for ptau217 was excellent (r=0.96), improving further after natural log transformation. GFAP and NfL also demonstrated moderate to strong correlations (r=0.86 for GFAP and r=0.99 for NfL), with normalization reducing variability.
Conclusions
Plasma biomarker measurements were consistent across laboratories using identical Simoa platforms, with strong diagnostic performance and improved agreement after normalization. These findings support the scalability of plasma biomarkers for multicenter studies and underscore their potential for standardized applications in AD research and clinical practice.
5.Analysis of distress in patients undergoing radical prostatectomy: A multicenter prospective study
Duk Yoon KIM ; Jae Hyun RYU ; Tag Keun YOO ; Yun Beom KIM ; Tae Young JUNG ; Woo Jin KO ; Eun Kyoung YANG
Investigative and Clinical Urology 2024;65(1):40-52
Purpose:
To analyze the degree of psychological distress experienced pre- and postoperatively in patients who underwent radical prostatectomy after being diagnosed with prostate cancer.
Materials and Methods:
Patients diagnosed with prostate cancer who underwent radical prostatectomy without history of psychiatric disorders were included in this study. The degree of psychological distress was evaluated using hospital anxiety and depression scale (HADS) and distress thermometer (DT) questionnaires preoperatively and at 1, 3, 6, and 12 months postoperatively.
Results:
Distress was high preoperatively and decreased over the entire period. In addition, HADS-anxiety and HADS-depression scores showed an improved severity, shifting from an abnormal state to a borderline state in some patients. However, the DT score, including emotional problems, spiritual concerns, physical problems, family problems, and practical problems, was slightly higher at 1 month postoperatively compared to preoperatively. Furthermore, even at 12 months postoperatively, about one fifth of patients surveyed had a DT score of 4 or higher, requiring psychiatric intervention.
Conclusions
Before and after radical prostatectomy, a significant number of patients complained of distress such as anxiety, depression, and insomnia, and they needed help from a specialist because of psychological distress even 12 months postoperatively.Therefore, a close evaluation of the patient’s psychological distress and supportive treatment are needed during the entire pre- and postoperative period.
6.Programmed Follow-up and Quality Control of Treatment Techniques Enhance Chronic Thromboembolic Pulmonary Hypertension Management:Lessons From a Multidisciplinary Team
Taek Kyu PARK ; Sung-A CHANG ; Jeong Hoon YANG ; Woochan KWON ; Min Yeong KIM ; Young Seok CHO ; Hye Yun PARK ; Dong Seop JEONG ; Hojoong KIM ; Duk kyung KIM
Korean Circulation Journal 2024;54(7):409-421
Background and Objectives:
The recent developments in chronic thromboembolic pulmonary hypertension (CTEPH) are emphasizing the multidisciplinary team. We report on the changes in clinical practice following the development of a multidisciplinary team, based on our 7 years of experience.
Methods:
Multidisciplinary team was established in 2015 offering both balloon pulmonary angioplasty (BPA) and pulmonary endarterectomy (PEA) with technical upgrades by internal and external expertise. For operable cases, PEA was recommended as the primary treatment modality, followed by pulmonary angiography and right heart catheterization after 6 months to evaluate treatment effect and identify patients requiring further BPA. For patients with inoperable anatomy or high surgical risk, BPA was recommended as the initial treatment modality. Patient data and clinical outcomes were closely monitored.
Results:
The number of CTEPH treatments rapidly increased and postoperative survival improved after team development. Before the team, 38 patients were treated by PEA for 18 years; however, 125 patients were treated by PEA or BPA after the team for 7 years. The number of PEA performed was 64 and that of BPA 342 sessions. World Health Organization functional class I or II was achieved in 93% of patients. The patients treated with PEA was younger, male dominant, higher pulmonary artery pressure, and smaller cardiac index, than BPA-only patients. In-hospital death after PEA was only 1 case and none after BPA.
Conclusions
The balanced development of BPA and PEA through a multidisciplinary team approach proved synergistic in increasing the number of actively treated CTEPH patients and improving clinical outcomes.
7.Effectiveness and Safety of Golimumab in Patients with Ulcerative Colitis: A Multicenter, Prospective, Postmarketing Surveillance Study
Jongwook YU ; Soo Jung PARK ; Hyung Wook KIM ; Yun Jeong LIM ; Jihye PARK ; Jae Myung CHA ; Byong Duk YE ; Tae Oh KIM ; Hyun-Soo KIM ; Hyun Seok LEE ; Su Young JUNG ; Youngdoe KIM ; Chang Hwan CHOI
Gut and Liver 2022;16(5):764-774
Background/Aims:
Golimumab has been used for patients with ulcerative colitis (UC) since 2013. However, there is limited data on the effectiveness and safety of the real-world use of golimumab in Asian patients.
Methods:
This was a multicenter, prospective, observational study. We enrolled patients with moderate-to-severe UC who were administered subcutaneous golimumab at 46 medical centers between May 2014 and November 2019. The primary outcome was the effectiveness and safety of golimumab at week 22. Clinical outcomes and adverse events were assessed according to partial Mayo score at weeks 0, 2, 6, 14, and 22.
Results:
A total of 130 patients were included (mean age: 45.7±16.0 years). The clinical response/ remission rates at weeks 2, 6, 14, and 22 were 40.4%/22.9%, 56.0%/35.8%, 70.6%/49.5%, and 67.9%/48.6%, respectively. Based on full Mayo score at week 14, clinical response and remission rates were 84.2% and 39.5%, respectively. Mucosal healing rate was 65.8%. In multivariate analysis with logistic regression, longer disease duration was significantly associated with a higher clinical response rate (adjusted odds ratio [aOR], 1.136; 95% confidence interval [CI], 1.006 to 1.282; p=0.040 at week 6; aOR, 1.256; 95% CI, 1.049 to 1.503; p=0.013 at week 22). A higher baseline Mayo endoscopic subscore was significantly associated with a lower clinical response rate at week 6 (aOR, 0.248; 95% CI, 0.089 to 0.692; p=0.008). The incidence of adverse drug reactions was 4.6% (6/130, nine events). No serious unexpected adverse drug reactions or deaths were reported.
Conclusions
Golimumab was effective and safe as an induction and maintenance treatment for Korean patients with moderate-to-severe UC.
8.Practice Patterns of Korean Urologists Regarding Positive Surgical Margins after Radical Prostatectomy: a Survey and Narrative Review
Jae Hyun RYU ; Yun Beom KIM ; Tae Young JUNG ; Woo Jin KO ; Sun Il KIM ; Dongdeuk KWON ; Duk Yoon KIM ; Tae Hee OH ; Tag Keun YOO
Journal of Korean Medical Science 2021;36(41):e256-
Background:
There is no clear consensus on the optimal treatment with curative intent for patients with positive surgical margins (PSMs) following radical prostatectomy (RP). The aim of this study was to investigate the perceptions and treatment patterns of Korean urologists regarding the resection margin after RP.
Methods:
A preliminary questionnaire was prepared by analyzing various studies on resection margins after RP. Eight experienced urologists finalized the 10-item questionnaire.In July 2019, the final questionnaire was delivered via e-mail to 105 urologists in Korea who specialize in urinary cancers.
Results:
We received replies from 91 of the 105 urologists (86.7%) in our sample population.Among them, 41 respondents (45.1%) had performed more than 300 RPs and 22 (24.2%) had completed 500 or more RPs. In the question about whether they usually performed an additional biopsy beyond the main specimen, to get information about surgical margin invasion during surgery, the main opinion was that if no residual cancer was suspected, it was not performed (74.7%). For PSMs, the Gleason score of the positive site (49.5%) was judged to be a more important prognostic factor than the margin location (18.7%), multifocality (14.3%), or margin length (17.6%). In cases with PSMs after surgery, the prevailing opinion on follow-up was to measure and monitor prostate-specific antigen (PSA) levels rather than to begin immediate treatment (68.1%). Many respondents said that they considered postoperative radiologic examinations when PSA was elevated (72.2%), rather than regularly (24.4%). When patients had PSMs without extracapsular extension (pT2R1) or a negative surgical margin with extracapsular extension (pT3aR0), the response ‘does not make a difference in treatment policy’ prevailed at 65.9%. Even in patients at high risk of PSMs on preoperative radiologic screening, 84.6% of the respondents said that they did not perform neoadjuvant androgen deprivation therapy. Most respondents (75.8%) indicated that they avoided nerve-sparing RP in cases with a high risk of PSMs, but 25.7% said that they had tried nerve-sparing surgery. Additional analyses showed that urologists who had performed 300 or more prostatectomies tended to attempt more nerve-sparing procedures in patients with a high risk of PSMs than less experienced surgeons (36.6% vs. 14.0%; P = 0.012).
Conclusion
The most common response was to monitor PSA levels without recommending any additional treatment when PSMs were found after RP. Through this questionnaire, we found that the perceptions and treatment patterns of Korean urologists differed considerably according to RP resection margin status. Refined research and standard practice guidelines are needed.
9.Effects of 17β-Estradiol on the Plasminogen Activator System in Vascular Smooth Muscle Cells Treated with Lysophophatidylcholine
Byung-Koo YOON ; Young-Hee KANG ; Won-Jong OH ; Dong-Yun LEE ; Duk-Kyung KIM ; Bruce KESSEL ; Chi-Dug KANG
Journal of Menopausal Medicine 2020;26(1):9-17
Objectives:
When administered soon after menopause, hormone therapy can prevent coronary heart diseases in women. To explore the mechanism underlying the cardioprotective actions of estrogen, we investigated the effects of 17β-estradiol (17β-E2) on the plasminogen activator system using cultured vascular smooth muscle cells (VSMCs).
Methods:
VSMCs were isolated from rat aortas. Protein expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were evaluated using Western blotting and enzyme-linked immunosorbent assay, respectively. The enzyme activity of PAI-1 in a conditioned medium was assessed via reverse fibrin overlay zymography and that of t-PA was assessed via fibrin overlay zymography. Gene expression was quantified using real-time reverse transcription-polymerase chain reaction.
Results:
Following pre-treatment for 24 hours, 17β-E2 suppressed both protein expression and enzyme activity of PAI-1 stimulated by lysophosphatidylcholine (lysoPC) in a significant and dose-dependent manner at a near physiological concentration. Moreover, 17β-E2 (10−7 M) inhibited PAI-1 gene expression, and ICI 182,780—a specific estrogen receptor antagonist—blocked the effects of 17β-E2 on the PAI-1 protein. 17β-E2 did not affect t-PA secretion but significantly enhanced free t-PA activity through reduced binding to PAI-1. Furthermore, 17β-E2 suppressed intracellular reactive oxygen species production and nuclear factor-κB-mediated transcription.
Conclusions
In VSMCs stimulated with lysoPC, 17β-E2 reduced PAI-1 expression through a non-receptor-mediated mechanism via antioxidant activity as well as a receptor-mediated mechanism; however, it did not alter t-PA secretion. Of note, 17β-E2 suppressed PAI- 1 activity and concurrently enhanced t-PA activity, suggesting a beneficial influence on fibrinolysis.
10.Sumoylation of histone deacetylase 1 regulates MyoD signaling during myogenesis
Hosouk JOUNG ; Sehee KWON ; Kyoung Hoon KIM ; Yun Gyeong LEE ; Sera SHIN ; Duk Hwa KWON ; Yeong Un LEE ; Taewon KOOK ; Nakwon CHOE ; Jeong Chul KIM ; Young Kook KIM ; Gwang Hyeon EOM ; Hyun KOOK
Experimental & Molecular Medicine 2018;50(1):e427-
Sumoylation, the conjugation of a small ubiquitin-like modifier (SUMO) protein to a target, has diverse cellular effects. However, the functional roles of the SUMO modification during myogenesis have not been fully elucidated. Here, we report that basal sumoylation of histone deacetylase 1 (HDAC1) enhances the deacetylation of MyoD in undifferentiated myoblasts, whereas further sumoylation of HDAC1 contributes to switching its binding partners from MyoD to Rb to induce myocyte differentiation. Differentiation in C2C12 skeletal myoblasts induced new immunoblot bands above HDAC1 that were gradually enhanced during differentiation. Using SUMO inhibitors and sumoylation assays, we showed that the upper band was caused by sumoylation of HDAC1 during differentiation. Basal deacetylase activity was not altered in the SUMO modification-resistant mutant HDAC1 K444/476R (HDAC1 2R). Either differentiation or transfection of SUMO1 increased HDAC1 activity that was attenuated in HDAC1 2R. Furthermore, HDAC1 2R failed to deacetylate MyoD. Binding of HDAC1 to MyoD was attenuated by K444/476R. Binding of HDAC1 to MyoD was gradually reduced after 2 days of differentiation. Transfection of SUMO1 induced dissociation of HDAC1 from MyoD but potentiated its binding to Rb. SUMO1 transfection further attenuated HDAC1-induced inhibition of muscle creatine kinase luciferase activity that was reversed in HDAC1 2R. HDAC1 2R failed to inhibit myogenesis and muscle gene expression. In conclusion, HDAC1 sumoylation plays a dual role in MyoD signaling: enhancement of HDAC1 deacetylation of MyoD in the basally sumoylated state of undifferentiated myoblasts and dissociation of HDAC1 from MyoD during myogenesis.
Creatine Kinase, MM Form
;
Gene Expression
;
Histone Deacetylase 1
;
Histone Deacetylases
;
Histones
;
Luciferases
;
Muscle Cells
;
Muscle Development
;
Myoblasts
;
Myoblasts, Skeletal
;
Sumoylation
;
Transfection

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