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Ishihara S, Hiramitsu S, Kanaoka K, Taki M, Nakagawa H, Ueda T, Seno A, Nishida T, Onoue K, Soeda T, Ohtani T, Watanabe M, Kawakami R, Sakata Y, Kario K, Saito Y. New Conversion Formula Between B-Type Natriuretic Peptide and N-Terminal-Pro-B-Type Natriuretic Peptide - Analysis From a Multicenter Study. Circ J 2022; 86:2010-2018. [PMID: 35613887 DOI: 10.1253/circj.cj-22-0032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Although B-type natriuretic peptide (BNP) and N-terminal (NT)-proBNP are commonly used markers of heart failure, a simple conversion formula between these peptides has not yet been developed for clinical use.Methods and Results: A total of 9,394 samples were obtained from Nara Medical University, Jichi Medical University, and Osaka University. We randomly selected 70% for a derivation set to investigate a conversion formula from BNP to NT-proBNP using estimated glomerular filtration rate (eGFR) and body mass index (BMI); the remaining 30% was used as the internal validation set and we used a cohort study from Nara Medical University as an external validation set. Multivariate linear regression analysis revealed a new conversion formula: log NT-proBNP = 1.21 + 1.03 × log BNP - 0.009 × BMI - 0.007 × eGFR (r2=0.900, P<0.0001). The correlation coefficients between the actual and converted values of log NT-proBNP in the internal and external validation sets were 0.942 (P<0.0001) and 0.891 (P<0.0001), respectively. We applied this formula to samples obtained from patients administered with sacubitril/valsartan. After treatment initiation, NT-proBNP levels decreased and actual BNP levels increased. However, the calculated BNP levels decreased roughly parallel to the NT-proBNP levels. CONCLUSIONS This new and simple conversion formula of BNP and NT-proBNP with eGFR and BMI is potentially useful in clinical practice.
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Affiliation(s)
- Satomi Ishihara
- Department of Cardiovascular Medicine, Nara Medical University
| | | | - Koshiro Kanaoka
- Department of Cardiovascular Medicine, Nara Medical University
| | - Mizuri Taki
- Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University School of Medicine
| | | | - Tomoya Ueda
- Department of Cardiovascular Medicine, Nara Medical University
| | - Ayako Seno
- Department of Cardiovascular Medicine, Nara Medical University
| | - Taku Nishida
- Department of Cardiovascular Medicine, Nara Medical University
| | - Kenji Onoue
- Department of Cardiovascular Medicine, Nara Medical University
| | - Tsunenari Soeda
- Department of Cardiovascular Medicine, Nara Medical University
| | - Tomohito Ohtani
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine
| | - Makoto Watanabe
- Department of Cardiovascular Medicine, Nara Medical University
| | - Rika Kawakami
- Department of Cardiovascular Medicine, Nara Medical University
| | - Yasushi Sakata
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine
| | - Kazuomi Kario
- Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University School of Medicine
| | - Yoshihiko Saito
- Department of Cardiovascular Medicine, Nara Medical University
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Willemse EA, van Maurik IS, Tijms BM, Bouwman FH, Franke A, Hubeek I, Boelaarts L, Claus JJ, Korf ES, van Marum RJ, Roks G, Schoonenboom N, Verwey N, Zwan MD, Wahl S, van der Flier WM, Teunissen CE. Diagnostic performance of Elecsys immunoassays for cerebrospinal fluid Alzheimer's disease biomarkers in a nonacademic, multicenter memory clinic cohort: The ABIDE project. Alzheimers Dement (Amst) 2018; 10:563-572. [PMID: 30406175 PMCID: PMC6215060 DOI: 10.1016/j.dadm.2018.08.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Introduction We compared the automated Elecsys and manual Innotest immunoassays for cerebrospinal fluid (CSF) Alzheimer's disease biomarkers in a multicenter diagnostic setting. Methods We collected CSF samples from 137 participants in eight local memory clinics. Amyloid β(1–42) (Aβ42), total tau (t-tau), and phosphorylated tau (p-tau) were centrally analyzed with Innotest and Elecsys assays. Concordances between methods were assessed. Results Biomarker results strongly correlated between assays with Spearman's ρ 0.94 for Aβ42, 0.98 for t-tau, and 0.98 for p-tau. Using Gaussian mixture modeling, cohort-specific cut-points were estimated at 1092 pg/mL for Aβ42, 235 pg/mL for t-tau, and 24 pg/mL for p-tau. We found an excellent concordance of biomarker abnormality between assays of 97% for Aβ42 and 96% for both t-tau and p-tau. Discussion The high concordances between Elecsys and Innotest in this nonacademic, multicenter cohort support the use of Elecsys for CSF Alzheimer's disease diagnostics and allow conversion of results between methods. Method comparison of 137 CSF samples collected in eight nonacademic memory clinics. Innotest and Elecsys strongly correlated: ρ = 0.94 Aβ42; 0.98 t-tau; 0.98 p-tau. Concordances of biomarker abnormalities: 97% Aβ42; 96% t-tau and p-tau. Concordance of NIA-AA–based Alzheimer's disease profile (Aβ42 decreased and p-tau increased): 89%. Preanalytical protocol deviations did not show effects on biomarker correlations.
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Affiliation(s)
- Eline A.J. Willemse
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Department of Neurology, Alzheimer Center, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Corresponding author. Tel.: +31-20-44-43029; Fax: +31-20-44-43857.
| | - Ingrid S. van Maurik
- Department of Neurology, Alzheimer Center, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Epidemiology and Biostatistics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Betty M. Tijms
- Department of Neurology, Alzheimer Center, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Femke H. Bouwman
- Department of Neurology, Alzheimer Center, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | | | - Isabelle Hubeek
- Department of Clinical Chemistry, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Leo Boelaarts
- Department of Geriatric Medicine, Noordwest Hospital Group, Alkmaar, The Netherlands
| | - Jules J. Claus
- Department of Neurology, Tergooi Hospital, Hilversum, The Netherlands
| | - Esther S.C. Korf
- Department of Neurology, Admiraal De Ruyter Hospital, Goes, The Netherlands
| | - Rob J. van Marum
- Department of Geriatrics, Jeroen Bosch Hospital, 's-Hertogenbosch, The Netherlands
- Department of Family Medicine and Elderly Care Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Gerwin Roks
- Department of Neurology, Elisabeth Tweesteden Hospital (ETZ), Tilburg, The Netherlands
| | | | - Nicolaas Verwey
- Department of Neurology, Medisch Centrum Leeuwarden, Leeuwarden, The Netherlands
| | - Marissa D. Zwan
- Department of Neurology, Alzheimer Center, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | | | - Wiesje M. van der Flier
- Department of Neurology, Alzheimer Center, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Epidemiology and Biostatistics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Charlotte E. Teunissen
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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Meyers A, Furtmann C, Jose J. Direct optical density determination of bacterial cultures in microplates for high-throughput screening applications. Enzyme Microb Technol 2018; 118:1-5. [PMID: 30143192 DOI: 10.1016/j.enzmictec.2018.06.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 06/29/2018] [Accepted: 06/30/2018] [Indexed: 11/29/2022]
Abstract
A convenient and most abundantly applied method to determine the growth state of a bacterial cell culture is to determine the optical density (OD) spectrophotometrically. Dilution of the samples, which is necessary to measure within the linear range of the spectrophotometer, is time-consuming and not compatible with high-throughput applications. Here we present a direct approach to estimate the OD at 578 nm (OD578) of bacterial cultures in microplates without the need for sample dilution. This could be advantageous for high-throughput analysis of bacterial cells in microplates for example when optimizing growth conditions, screening for new substrates of a bacterial strain or monitoring enzymatic activity after enzyme evolution. Pseudomonas putida cells were grown in shake flasks. The OD578 was determined in parallel in a microplate directly without dilution and in a spectrophotometer cuvette after dilution. The resulting data set was used to identify a conversion formula, which enables direct and reliable transformation of OD measurements of undiluted samples into the corrected OD values as would have been obtained for diluted samples measured in a standard spectrophotometer. Subsequently we could show that just a few OD calibration points are required to adjust this conversion formula and make it suitable for other suspensions or cultures of bacterial strains different than P. putida. The OD calibration points can be obtained by any combination of microplate reader and cuvette spectrophotometer. For this purpose, conversion formulas for a formazine standard suspension and a suspension of Escherichia coli BL21(DE3) cells were successfully generated. The OD values calculated by both conversion formulas turned out to be identical with the values as obtained by the control measurements in the spectrophotometer. This indicates the general applicability of the conversion formula as described.
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Affiliation(s)
- Annika Meyers
- Institute of Pharmaceutical and Medicinal Chemistry, PharmaCampus, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149 Münster, Germany
| | - Christoph Furtmann
- Institute of Pharmaceutical and Medicinal Chemistry, PharmaCampus, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149 Münster, Germany
| | - Joachim Jose
- Institute of Pharmaceutical and Medicinal Chemistry, PharmaCampus, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149 Münster, Germany.
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