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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. |
- van der Harst, Pim, et al.
(författare)
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Telomere length and outcome in heart failure.
- 2010
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Ingår i: Annals of Medicine. - : Informa UK Limited. - 0785-3890 .- 1365-2060. ; 42:1, s. 36-44
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Telomeres are causally involved in senescence. Senescence is a potential factor in the pathogenesis and progression of heart failure. In heart failure telomeres are shorter, but the prognostic value associated with telomere length has not been defined. METHODS: Telomere length was prospectively determined by quantitative polymerase chain reaction in 890 patients with New York Heart Association (NYHA) functional class II to IV heart failure. After 18 months, we examined the association between telomere length and the predefined primary end-point: time to death or hospitalization for heart failure. RESULTS: Mean age of the patients was 71 years, 39% were women, 51% were in NYHA class II, and 49% were in class III/IV. A total of 344 patients reached the primary end-point (130 deaths and 214 hospitalizations). Patients with shorter telomeres were at an increased risk of reaching the primary end-point (hazard ratio 1.79; 95% confidence interval (CI) 1.21-2.63). In multivariate analysis shorter telomere length remained associated with a higher risk for death or hospitalization (hazard ratio, 1.74; 95% CI 1.07-2.95) after adjustment for age of heart failure onset, gender, hemoglobin, renal function, and N-terminal pro-B-type natriuretic peptide level, a history of stroke, atrial fibrillation, and diabetes. CONCLUSIONS: Shorter length of telomeres predicts the occurrence of death or hospitalization in patients with chronic heart failure.
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| 4. |
- Wong, Liza S M, et al.
(författare)
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Anaemia is associated with shorter leucocyte telomere length in patients with chronic heart failure.
- 2010
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Ingår i: European Journal of Heart Failure. - : Wiley. - 1388-9842 .- 1879-0844. ; 12:4, s. 348-53
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Anaemia is highly prevalent and associated with poor prognosis in patients with chronic heart failure (CHF). Reduced erythroid proliferation capacity of haematopoietic progenitor cells is associated with reduced telomere length, a marker of cellular ageing. We hypothesize that short telomere length contributes to the susceptibility to develop anaemia in patients with CHF. METHODS AND RESULTS: We studied 875 CHF patients, of whom 254 (29%) fulfilled the WHO criteria of anaemia. Telomere length in DNA from peripheral leucocytes was measured with real-time quantitative polymerase chain reaction. Age, gender, and baseline differences adjusted telomere length was correlated with haemoglobin levels (partial r = 0.130; P = 0.011). One standard deviation shorter telomere length was associated with an increased risk of having anaemia [odds ratio (OR), 1.31; 95% confidence interval (CI), 1.12-1.53; P = 0.001]. This observation was not affected by adjustment for potential confounders (OR, 1.38; 95% CI, 1.05-1.81; P = 0.021 after adjustment for age, gender, erythropoietin levels, renal function, left ventricular ejection fraction, age of CHF onset, blood pressure, history of stroke, diabetes, and B-type natriuretic peptide levels). CONCLUSION: Shorter telomere length increases the odds of having anaemia in CHF patients. This finding supports the hypothesis that cellular ageing in CHF contributes to the susceptibility to develop anaemia.
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| 5. |
- Wong, Liza S M, et al.
(författare)
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Renal dysfunction is associated with shorter telomere length in heart failure.
- 2009
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Ingår i: Clinical research in cardiology : official journal of the German Cardiac Society. - : Springer Science and Business Media LLC. - 1861-0692. ; 98:10, s. 629-34
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Renal dysfunction is a frequent comorbidity associated with high mortality in patients with chronic heart failure (CHF). The intrinsic biological age might affect the ability of the kidney to cope with the challenging environment caused by CHF. We explored the association between leukocyte telomere length, a marker for biological age, and renal function in patients with CHF. METHODS AND RESULTS: Telomere length was determined by a real-time quantitative polymerase chain reaction in 866 CHF patients. Renal function was estimated with the simplified Modification of Diet in Renal Disease equation. The median age was 74 (interquartile range 64-79) years, 61% male, left ventricular ejection fraction of 30 (23-44)%, and the estimated glomerular filtration rate was 53 (40-68) ml/min/1.73 m(2). Telomere length was associated with renal function (correlation coefficient 0.123, P < 0.001). This relationship remained significant after adjustment for age, gender, age of CHF onset (standardized-beta 0.091, P = 0.007). Also additionally adjusting for the severity of CHF and baseline differences did not change our findings. CONCLUSION: The association between shorter leukocyte telomere length and reduced renal function in heart failure suggests that intrinsic biological aging affects the ability of the kidney to cope with the systemic changes evoked by heart failure.
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