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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. |
- Elias, Khalid, et al.
(författare)
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Prevalence and impact of acid-related symptoms and diarrhea in patients undergoing Roux-en-Y gastric bypass, sleeve gastrectomy, and biliopancreatic diversion with duodenal switch
- 2020
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Ingår i: Surgery for Obesity and Related Diseases. - : ELSEVIER SCIENCE INC. - 1550-7289 .- 1878-7533. ; 16:4, s. 520-527
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Tidskriftsartikel (refereegranskat)abstract
- Background: Gastrointestinal symptoms are common in the obese population. Objectives: To determine the prevalence and importance of acid-related symptoms and diarrhea in 3 different types of bariatric operations: Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG), and biliopancreatic diversion with duodenal switch (BPD/DS). Setting: National data from Sweden. Methods: A total of 58,823 primary bariatric procedures (RYGB: 87.5%, SG: 11.7%, and BPD/DS: .7%) performed from 2007 to 2017 were identified in the Scandinavian Obesity Surgery Registry. Associations between acid-related symptoms and diarrhea, both defined by continuous use of pharmacologic treatment, and predefined outcomes were studied in a multivariate model, adjusted for age, sex, body mass index, and year of surgery. Results: At baseline, acid-related symptoms were most common in RYGB (9.9%), while diarrhea was rare. In general, symptomatic patients were older, had more co-morbidities, and scored lower on quality of life compared with the remaining patients. In the multivariate analysis, RYGB patients with acid-related symptoms had reduced risk of prolonged operative time and length of stay, while postoperative complications and reoperations increased by 24% and 36%, respectively. In SG, both symptoms were associated with prolonged operative time and a doubled risk for complications. Symptomatic patients had reduced improvement in quality of life, while no association with the weight result was seen. Postoperatively, acid-related symptoms decreased in RYGB, while doubling in SG. Diarrhea increased 2- and 6-fold in RYGB and BPD/DS, respectively. Conclusion: The 2 gastrointestinal symptoms were associated with increased operative risks and reduced improvement in quality of life. Postoperatively, the respective anatomic alternations affected both gastrointestinal symptoms. (C) 2020 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.
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