1.Development and Validation of a Novel Isotope Dilution-Ultraperformance Liquid ChromatographyTandem Mass Spectrometry Method for Serum C-Peptide
Sung-Eun CHO ; Jungsun HAN ; Juyoung YOU ; Jun Hyung LEE ; Ahram YI ; Sang Gon LEE ; Eun Hee LEE
Annals of Laboratory Medicine 2025;45(1):62-69
Background:
Mass spectrometry (MS) methods exhibit higher accuracy and comparability in measuring serum C-peptide concentrations than immunoassays. We developed and validated a novel isotope dilution-ultraperformance liquid chromatography-tandem MS (IDUPLC-MS/MS) assay to measure serum C-peptide concentrations.
Methods:
Sample pretreatment involved solid-phase extraction, ion-exchange solid-phase extraction, and derivatization with 6-aminoquinolyl-N-hydroxysuccinimidylcarbamate (Cayman Chemical, Ann Arbor, Michigan, USA). We used an ExionLC UPLC system (Sciex, Framingham, MA, USA) and a Sciex Triple Quad 6500 + MS/MS system (Sciex) for electrospray ionization in positive-ion mode with multiple charge states of [M+3H]3+ and multiple reaction monitoring transitions. The total run time was 50 mins, and the flow rate was 0.20 mL/min. We evaluated the precision, trueness, linearity, lower limit of quantitation (LLOQ), carryover, and matrix effects. Method comparison with electrochemiluminescence immunoassay (ECLIA) was performed in 138 clinical specimens.
Results:
The intra- and inter-run precision coefficients of variation were < 5% and the bias values for trueness were < 4%, which were all acceptable. The verified linear interval was 0.050–15 ng/mL, and the LLOQ was 0.050 ng/mL. No significant carryover or matrix effects were observed. The correlation between this ID-UPLC-MS/MS method and ECLIA was good (R = 0.995, slope = 1.564); however, the ECLIA showed a positive bias (51.8%).
Conclusions
The developed ID-UPLC-MS/MS assay shows acceptable performance in measuring serum C-peptide concentrations. This will be useful in situations requiring accurate measurement of serum C-peptide in clinical laboratories.
2.What are the Barriers to Antenatal Care Utilization in Rufisque District, Senegal?: a Bottleneck Analysis
Kyung Hee KIM ; Jae Wook CHOI ; Jiyoung OH ; Juyoung MOON ; Seonghae YOU ; YongKyoung WOO
Journal of Korean Medical Science 2019;34(7):e62-
BACKGROUND: This study aimed to analyze the barriers affecting the utilization of antenatal care (ANC) among Senegalese mothers. METHODS: Health facility staffs were surveyed to examine the availability coverage of ANC (infrastructural capacity of health posts to handle maternal and newborn healthcare). A total of 113 women of childbearing age were surveyed to identify factors associated with the accessibility coverage (physical, economic, and information accessibility factors), acceptability coverage (socio-cultural features, social acceptance, and language), and effectiveness coverage (ratio of mothers having completed 4 visits) of ANC. Further, to identify the socio-cultural factors and the specific characteristics of the barriers, 5 focus group discussions were conducted with women of childbearing age, their husbands and mothers-in-law, community health workers, and health facility staff. The effectiveness coverage of ANC was analyzed by reviewing materials from the District Health Information System 2 of Senegal. RESULTS: Key barriers of ANC utilization were associated with acceptability coverage. ANC during early pregnancy was avoided owing to the negative social stigma surrounding miscarriage. The survey results indicated an extremely high miscarriage rate of 30.9% among the participants. The social stigma towards unmarried mothers caused them to hide their pregnancy, which deterred ANC utilization. The husband was the final decision maker and social supporter on ANC utilization. CONCLUSION: To promote the utilization of ANC services among pregnant women in Senegal, it is important to alleviate the social stigma towards miscarriages and unmarried mothers, and to provide greater social support for pregnancies and newborn deliveries within family.
Abortion, Spontaneous
;
Community Health Workers
;
Female
;
Focus Groups
;
Health Facilities
;
Health Information Systems
;
Humans
;
Illegitimacy
;
Infant Health
;
Infant, Newborn
;
Maternal Health
;
Mothers
;
Patient Acceptance of Health Care
;
Pregnancy
;
Pregnant Women
;
Senegal
;
Social Distance
;
Social Stigma
;
Spouses
3.Acquired Hemophilia A Combined with Systemic Lupus Erythematosus: A Case Report and Literature Review.
Juyoung YOU ; Hojae KIM ; Jin Su PARK ; Myung Hee CHANG ; Chan Hee LEE
Journal of Rheumatic Diseases 2017;24(5):309-312
Acquired hemophilia A (AHA) is a rare hemorrhagic disorder caused by autoantibodies against factor VIII (FVIII). An 80-year-old woman presented multiple bruises on her upper and lower extremities, along with gross hematuria. Extensive ecchymosis and swelling were observed on the buttocks. She had anemia and normal platelet count. The initial coagulation results showed prolonged activated partial thromboplastin time (aPTT, 68.5 seconds) and normal prothrombin time. According to the mixing test, we observed a decreased FVIII activity (2%), increased factor VIII inhibitor (FVIII-I) titer (74.4 BU), and negative lupus anticoagulant. AHA was diagnosed based on late onset bleeding and increased FVIII-I titer. Additionally, she met the criteria for systemic lupus erythematosus (oral ulcer, photosensitivity, renal disorder, and positivity for antinuclear and anti-β2-glycoprotein-I antibodies). She was started on oral prednisolone for FVIII-I eradication. Post-treatment, her bleeding tendency, aPTT (47.3 seconds), and FVIII-I titer decreased (1.24 BU), and FVIII activity increased (10%).
Aged, 80 and over
;
Anemia
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Autoantibodies
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Buttocks
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Contusions
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Ecchymosis
;
Factor VIII
;
Female
;
Hematuria
;
Hemophilia A*
;
Hemorrhage
;
Hemorrhagic Disorders
;
Humans
;
Lower Extremity
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Lupus Coagulation Inhibitor
;
Lupus Erythematosus, Systemic*
;
Partial Thromboplastin Time
;
Platelet Count
;
Prednisolone
;
Prothrombin Time
;
Ulcer

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