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- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
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| 3. |
- Ratziu, Vladimir, et al.
(författare)
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Cost of non-alcoholic steatohepatitis in Europe and the USA: The GAIN study
- 2020
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Ingår i: JHEP Reports. - : Elsevier. - 2589-5559 .- 2589-5559. ; 2:5
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundXX1Aims: Non-alcoholic steatohepatitis (NASH) leads to cirrhosis and is associated with a substantial socioeconomic burden, which, coupled with rising prevalence, is a growing public health challenge. However, there are few real-world data available describing the impact of NASH.Methods: The Global Assessment of the Impact of NASH (GAIN) study is a prevalence-based burden of illness study across Europe (France, Germany, Italy, Spain, and the UK) and the USA. Physicians provided demographic, clinical, and economic patient information via an online survey. In total, 3,754 patients found to have NASH on liver biopsy were stratified by fibrosis score and by biomarkers as either early or advanced fibrosis. Per-patient costs were estimated using national unit price data and extrapolated to the population level to calculate the economic burden. Of the patients, 767 (20%) provided information on indirect costs and health-related quality of life using the EuroQOL 5-D (EQ-5D; n = 749) and Chronic Liver Disease Questionnaire - Non-Alcoholic Fatty Liver Disease (CLDQ-NAFLD) (n = 723).Results: Mean EQ-5D and CLDQ-NAFLD index scores were 0.75 and 4.9, respectively. For 2018, the mean total annual per patient cost of NASH was (sic)2,763, (sic)4,917, and (sic)5,509 for direct medical, direct non-medical, and indirect costs, respectively. National per-patient cost was highest in the USA and lowest in France. Costs increased with fibrosis and decompensation, driven by hospitalisation and comorbidities. Indirect costs were driven by work loss.Conclusions: The GAIN study provides real-world data on the direct medical, direct non-medical, and indirect costs associated with NASH, including patient-reported outcomes in Europe and the USA, showing a substantial burden on health services and individuals. (C) 2020 The Author(s). Published by Elsevier B.V. on behalf of European Association for the Study of the Liver (EASL).
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| 5. |
- Vialas, Vital, et al.
(författare)
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A multicentric study to evaluate the use of relative retention times in targeted proteomics
- 2017
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Ingår i: Journal of Proteomics. - : Elsevier BV. - 1874-3919. ; 152, s. 138-149
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Tidskriftsartikel (refereegranskat)abstract
- Despite the maturity reached by targeted proteomic strategies, reliable and standardized protocols are urgently needed to enhance reproducibility among different laboratories and analytical platforms, facilitating a more widespread use in biomedical research. To achieve this goal, the use of dimensionless relative retention times (iRT), defined on the basis of peptide standard retention times (RT), has lately emerged as a powerful tool. The robustness, reproducibility and utility of this strategy were examined for the first time in a multicentric setting, involving 28 laboratories that included 24 of the Spanish network of proteomics laboratories (ProteoRed-ISCIII). According to the results obtained in this study, dimensionless retention time values (iRTs) demonstrated to be a useful tool for transferring and sharing peptide retention times across different chromatographic set-ups both intra- and inter-laboratories. iRT values also showed very low variability over long time periods. Furthermore, parallel quantitative analyses showed a high reproducibility despite the variety of experimental strategies used, either MRM (multiple reaction monitoring) or pseudoMRM, and the diversity of analytical platforms employed. Biological significance From the very beginning of proteomics as an analytical science there has been a growing interest in developing standardized methods and experimental procedures in order to ensure the highest quality and reproducibility of the results. In this regard, the recent (2012) introduction of the dimensionless retention time concept has been a significant advance. In our multicentric (28 laboratories) study we explore the usefulness of this concept in the context of a targeted proteomics experiment, demonstrating that dimensionless retention time values is a useful tool for transferring and sharing peptide retention times across different chromatographic set-ups.
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