| 1. |
- Beal, Jacob, et al.
(författare)
-
Robust estimation of bacterial cell count from optical density
- 2020
-
Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
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.
|
|
| 2. |
- Saad, Ayman, et al.
(författare)
-
Impact of T Cell Dose on Outcome of T Cell-Replete HLA-Matched Allogeneic Peripheral Blood Stem Cell Transplantation
- 2019
-
Ingår i: Biology of blood and marrow transplantation. - : ELSEVIER SCIENCE INC. - 1083-8791 .- 1523-6536. ; 25:9, s. 1875-1883
-
Tidskriftsartikel (refereegranskat)abstract
- Data on whether the T cell dose of allogeneic peripheral blood stem cell (PBSC) products influences transplantation outcomes are conflicting. Using the Center for International Blood and Marrow Transplant Research database, we identified 2736 adult patients who underwent first allogeneic PBSC transplantation for acute leukemia or myelodysplastic syndrome between 2008 and 2014 using an HLA-matched sibling donor (MSD) or an 8/8-matched unrelated donor (MUD). We excluded ex vivo and in vivo T cell-depleted transplantations. Correlative analysis was performed between CD3(+) T cell dose and the risk of graft-versus-host-disease (GVHD), relapse, nonrelapse mortality (NRM), disease-free survival (DFS), and overall survival (OS). Using maximum likelihood estimation, we identified CD3(+) T cell dose cutoff that separated the risk of acute GVHD (aGVHD) grade II-IV in both the MSD and MUD groups. A CD3(+) T cell dose cutoff of 14 x 10(7) cells/kg identified MSD/low CD3(+) (n = 223) and MSD/high CD3(+) (n = 1214), and a dose of 15 x 107 cells/kg identified MUD/low (n = 197) and MUD/high CD3(+) (n = 1102). On univariate analysis, the MSD/high CD3(+) group had a higher cumulative incidence of day +100 aGVHD grade II-IV compared with the MSD/low CD3(+) group (33% versus 25%; P=.009). There were no differences between the 2 groups in engraftment rate, risk of aGVHD grade III-IV or chronic GVHD (cGVHD), NRM, relapse, DFS, or OS. The MUD/high CD3(+) group had a higher cumulative incidence of day +100 aGVHD grade II-IV compared with the MUD/low CD3(+) group (49% versus 41%; P=.04). There were no differences between the 2 groups in engraftment rate, risk of severe aGVHD or cGVHD, NRM, relapse, DFS, or OS. Multivariate analysis of the MSD and MUD groups failed to show an association between CD3(+) T cell dose and the risk of either aGVHD grade II-IV (P=.10 and .07, respectively) or cGVHD (P = .80 and .30, respectively). Subanalysis of CD4(+) T cells, CD8(+) T cells, and CD4+/CD8+ ratio failed to identify cutoff values predictive of transplantation outcomes; however, using the log-rank test, the sample size was suboptimal for identifying a difference at this cutoff cell dose. In this registry study, the CD3(+) T cell dose of PBSC products did not influence the risk of aGVHD or cGVHD or other transplantation outcomes when using an MSD or an 8/8-matched MUD. Subset analyses of CD4(+) and CD8(+) T cell doses were not possible given our small sample size. (C) 2019 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.
|
|
