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3 results on '"L. Chapell"'

1. 94-OR

Author

Hannele Laivuori, Lucilla Poston, Anne Cathrine Staff, M. Moertl, Harald Zeisler, C. Hubel, Claudia Holzman, James M. Roberts, Gayle Olson, E. Schistermann, Ulla Breth Knudsen, David J. Williams, Christopher W.G. Redman, Ignacio Herraiz, Orlaith Burke, Irene Cetin, Thomas F. McElrath, Samantha J. Benton, Stefan Verlohren, D. Schlemback, C. Zhang, Pia M. Villa, P. von Dadelszen, Olav Lapaire, Roberta B. Ness, L. Chapell, L. Oliviera, Eric A.P. Steegers, Vassilis Tsatsaris, Carrie Ris-Stalpers, J. Meyers, Francesc Figueras, Catalin S. Buhimschi, J.A.M. van der Post, S. Timmermans, Holger Stepan, Alberto Galindo, Camilla Kronborg, and Pawel Szafranski

Subjects
business.industry, Obstetrics and Gynecology, Diagnostic marker, Patient data, 030204 cardiovascular system & hematology, medicine.disease, Preeclampsia, 03 medical and health sciences, 0302 clinical medicine, Sample size determination, Potential biomarkers, Clinical heterogeneity, Internal Medicine, Medicine, Biomarker (medicine), 030212 general & internal medicine, business, Algorithm
Abstract

Objectives Circulating placental growth factor (PlGF) is a potential biomarker for preeclampsia. Prior studies show its limited precision in predicting or diagnosing preeclampsia, underscoring a common problem in biomarker data analyses in general – that large studies are needed to overcome clinical heterogeneity and to provide sufficient statistical power. Attaining such sample sizes often requires aggregation of cohorts. Different studies may use disparate platforms for laboratory analyses, complicating data merging. Here, we assessed whether PlGF concentrations could be merged across studies using inter-platform standardization. Methods Of 16516 pregnancies from 23 cohorts, 12,804 had at least one PlGF concentration (gestational age >20 weeks), analyzed using one of four platforms: R&D Systems, Alere-Triage, Roche-Elecsys or Abbott-Architect. Two merging algorithms, using Z -Score or Multiple of Median (MOM) transformations, were applied. A single Best Reference Curve (BRC), based on merged non-case PlGF concentrations, was constructed. Case-identification performance of the BRC for PlGF was compared to platform-specific curves. Results PlGF concentrations from different analytical platforms were merged ( Z -scores marginally better than MOMs) and, overall, BRC case-identification rates out-performed platform-specific curves. Conclusions Laboratory measurements from different platforms can be standardised and merged to give reference curves from aggregated PlGF datasets. This method allows for analysis of PlGF as a diagnostic marker for preeclampsia and is generalisable to other medical questions, thereby extending the scope of individual studies to answer a variety of important medical questions. Disclosures O. Burke: None. S. Benton: None. P. Szafranski: None. P. von Dadelszen: None. C. Buhimschi: None. I. Cetin: None. L. Chapell: None. F. Figueras: None. A. Galindo: None. I. Herraiz: None. C. Holzman: None. C. Hubel: None. U. Knudsen: None. C. Kronborg: None. H. Laivuori: None. T. McElrath: None. M. Moertl: None. J. Meyers: None. R.B. Ness: None. L. Oliviera: None. G. Olson: None. L. Poston: None. C. Ris-Stalphers: None. J.M. Roberts: None. E. Schistermann: None. E. Steegers: None. H. Stepan: None. O. Lapaire: None. D. Schlembach: None. S. Timmermans: None. V. Tsatsaris: None. J.A. van der Post: None. S. Verlohren: Consultant, Research Support Recipient, Commercial Interest: Roche Diagnostics, ThermoFisher, Novartis. P.M. Villa: None. D. Williams: None. H. Zeisler: None. C. Zhang: None. C.W. Redman: None. A. Staff: None.

Published
2015
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2. Analysis of Small RNA Populations Using Hybridization to DNA Tiling Arrays.

Author

Boccara M, Sarazin A, Billoud B, Bulski A, Chapell L, Baulcombe D, and Colot V

Subjects
Arabidopsis genetics, Gene Library, Reproducibility of Results, Stress, Physiological genetics, Gene Expression Profiling methods, Nucleic Acid Hybridization methods, Oligonucleotide Array Sequence Analysis methods, RNA, Small Untranslated genetics
Abstract

Epigenetic response to stress in plants involves changes in DNA methylation, histone modifications, and expression of small noncoding RNAs (sRNA). Here we present the method of analysis of differential expression of sRNA populations using DNA tiling arrays. sRNA extracted from Arabidopsis thaliana plants exposed to pathogen elicitor or control plants were reverse-transcribed into cDNAs, and subsequently hybridized after labeling to a custom-made DNA tiling array covering Arabidopsis chromosome 4. We first designed a control experiment with eight cDNA clones corresponding to sequences located on chromosome 4 and obtained robust and specific hybridization signals. Furthermore, hybridization signals along chromosome 4 were in good agreement with sRNA abundance as previously determined by massive parallel sequence signature (MPSS) in the case of untreated plants, but differed substantially after stress treatment. These results demonstrate the utility of hybridization to DNA tiling arrays to detect major changes in sRNA abundance.

Published
2017
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3. Analysis of small RNA populations using hybridization to DNA tiling arrays.

Author

Boccara M, Sarazin A, Billoud B, Bulski A, Chapell L, Baulcombe D, and Colot V

Subjects
Arabidopsis chemistry, Chromosomes, Plant genetics, DNA, Complementary, DNA, Plant, Stress, Physiological genetics, Nucleic Acid Hybridization methods, Oligonucleotide Array Sequence Analysis, RNA, Plant analysis, RNA, Untranslated analysis
Abstract

Small RNA (sRNA) populations extracted from Arabidopsis plants submitted or not to biotic stress, were reverse-transcribed into cDNAs, and these were subsequently hybridized after labelling to a custom-made DNA tiling array covering Arabidopsis chromosome 4. We first designed a control experiment with eight cDNA clones corresponding to sequences located on chromosome 4 and obtained robust and specific hybridization signals. Furthermore, hybridization signals along chromosome 4 were in good agreement with sRNA abundance as previously determined by Massive Parallel Sequence Signature (MPSS) in the case of untreated plants, but differed substantially after stress treatment. These results demonstrate the utility of hybridization to DNA tiling arrays to detect major changes in small RNA populations.

Published
2010
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