| 1. |
- Abbafati, Cristiana, et al.
(författare)
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- 2020
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Lahrouchi, Najim, et al.
(författare)
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Transethnic Genome-Wide Association Study Provides Insights in the Genetic Architecture and Heritability of Long QT Syndrome
- 2020
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Ingår i: Circulation. - : Lippincott Williams & Wilkins. - 0009-7322 .- 1524-4539. ; 142:4, s. 324-338
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Tidskriftsartikel (refereegranskat)abstract
- Background: Long QT syndrome (LQTS) is a rare genetic disorder and a major preventable cause of sudden cardiac death in the young. A causal rare genetic variant with large effect size is identified in up to 80% of probands (genotype positive) and cascade family screening shows incomplete penetrance of genetic variants. Furthermore, a proportion of cases meeting diagnostic criteria for LQTS remain genetically elusive despite genetic testing of established genes (genotype negative). These observations raise the possibility that common genetic variants with small effect size contribute to the clinical picture of LQTS. This study aimed to characterize and quantify the contribution of common genetic variation to LQTS disease susceptibility. Methods: We conducted genome-wide association studies followed by transethnic meta-analysis in 1656 unrelated patients with LQTS of European or Japanese ancestry and 9890 controls to identify susceptibility single nucleotide polymorphisms. We estimated the common variant heritability of LQTS and tested the genetic correlation between LQTS susceptibility and other cardiac traits. Furthermore, we tested the aggregate effect of the 68 single nucleotide polymorphisms previously associated with the QT-interval in the general population using a polygenic risk score. Results: Genome-wide association analysis identified 3 loci associated with LQTS at genome-wide statistical significance (P<5x10(-8)) nearNOS1AP,KCNQ1, andKLF12, and 1 missense variant inKCNE1(p.Asp85Asn) at the suggestive threshold (P<10(-6)). Heritability analyses showed that approximate to 15% of variance in overall LQTS susceptibility was attributable to common genetic variation (h2SNP0.148; standard error 0.019). LQTS susceptibility showed a strong genome-wide genetic correlation with the QT-interval in the general population (r(g)=0.40;P=3.2x10(-3)). The polygenic risk score comprising common variants previously associated with the QT-interval in the general population was greater in LQTS cases compared with controls (P<10-13), and it is notable that, among patients with LQTS, this polygenic risk score was greater in patients who were genotype negative compared with those who were genotype positive (P<0.005). Conclusions: This work establishes an important role for common genetic variation in susceptibility to LQTS. We demonstrate overlap between genetic control of the QT-interval in the general population and genetic factors contributing to LQTS susceptibility. Using polygenic risk score analyses aggregating common genetic variants that modulate the QT-interval in the general population, we provide evidence for a polygenic architecture in genotype negative LQTS.
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| 3. |
- 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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| 4. |
- Hsu, Jack W., et al.
(författare)
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Collection of Peripheral Blood Progenitor Cells in 1 Day Is Associated with Decreased Donor Toxicity Compared to 2 Days in Unrelated Donors
- 2020
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Ingår i: Biology of blood and marrow transplantation. - : Elsevier BV. - 1083-8791 .- 1523-6536. ; 26:6, s. 1210-1217
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Tidskriftsartikel (refereegranskat)abstract
- Peripheral blood stem cells (PBSCs) have been increasingly used for allogeneic hematopoietic cell transplantation instead of bone marrow stem cells. Current National Marrow Donor Program policy recommends 5 days of daily filgrastim, followed by either 1 or 2 days of apheresis for unrelated donors, depending on collection center choice. To date, there are no published studies comparing the differences in donor experience between 1 day and 2 days of apheresis. We examined 22,348 adult unrelated donor collections in 184 centers between 2006 and 2016. Of these 22,348 donors, 20,004 (89.5%) had collection on 1 day, and the other 2344 (9.5%) had collection over 2 days. Information on why donors underwent apheresis in 1 day or 2 days was not available. Donors who underwent apheresis in 1 day were more likely to be male (67% versus 46%; P < .001), younger (age <30 years, 48% versus 36%; P < .001), and have a higher body weight (83.0 kg versus 75.9 kg; P< .001) and body mass index (BMI; >30, 30% versus 22%; P < .001). Successful collection of the requested CD34(+) cell count was achieved on the first day in 82% of 1-day collections and in 16% of 2-day collections. Despite not administering filgrastim the evening after the first day of collection in patients who underwent 2 days of apheresis, the median concentration of CD34' cells/I, in the product was higher on the second day of apheresis compared with the first day (23.8 x 10(6) CD34(+)/L. on day 1 versus 28.7 x 10(6) CD34(+)/L. on day 2; P< .001). Donors who underwent collection in 1 day were less likely to experience citrate toxicity (36% versus 52%; P< .001), hospitalization (1% versus 6%; P< .001), and other side effects related to apheresis (Modified Toxicity Criteria incidence: 20% versus 26%; P < .001). Female sex, older age, collection via central lines, and higher BMI were factors associated with greater likelihood for the development of toxicity, whereas less toxicity was noted in those with higher CD34(+) counts and more blood processed on the first day of collection. We conclude that although unrelated donors can be successfully collected in 1 day or 2 days, 1-day apheresis procedures were associated with less overall toxicity, and thus we recommend single-day collections, especially if the requested number of cells have been collected in 1 day.
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| 5. |
- Farhadfar, Nosha, et al.
(författare)
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Weighty choices : selecting optimal G-CSF doses for stem cell mobilization to optimize yield
- 2020
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Ingår i: Blood Advances. - : AMER SOC HEMATOLOGY. - 2473-9529 .- 2473-9537. ; 4:4, s. 706-716
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Tidskriftsartikel (refereegranskat)abstract
- There are limited data on the effect of donor body mass index (BMI) on peripheral blood stem cell (PBSC) mobilization response to granulocyte colony-stimulating factor (G-CSF), especially in unrelated donors. Obesity has been associated with persistent leukocytosis, elevated circulating progenitor cells, and enhanced stem cell mobilization. Therefore, we hypothesized that adequate collection of CD34(+) cells may be achieved with lower doses (per kilogram of body weight) of G-CSF in donors with higher BMI compared with donors with lower BMI. Using the Center for International Blood and Marrow Transplant Research database, we evaluated the impact of donor BMI on G-CSF-mobilized PBSC yield in healthy unrelated donors. We examined 20 884 PBSC donations collected at National Marrow Donor Program centers between 2006 and 2016. We found significantly higher collection yields in obese and severely obese donors compared with normal and overweight donors. An increase in average daily G-CSF dose was associated with an increase in stem cell yield in donors with normal or overweight BMI. In contrast, an increase in average daily G-CSF dose beyond 780 mu g per day in obese and 900 mg per day in severely obese donors did not increase cell yield. Pain and toxicities were assessed at baseline, during G-CSF administration, and postcollection. Obesity was associated with higher levels of self-reported donation-related pain and toxicities in the pericollection and early postdonation recovery periods. This study suggests a maximum effective G-CSF dose for PBSC mobilization in obese and severely obese donors, beyond which higher doses of G-CSF add no increased yield.
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