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- Ekelund, Oskar, et al.
(författare)
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High-throughput immunoassays for SARS-CoV-2 : considerable differences in performance when comparing three methods
- 2021
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Ingår i: Infectious Diseases. - : Taylor & Francis. - 2374-4235 .- 2374-4243. ; 53:10, s. 805-810
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The recently launched high-throughput assays for detecting antibodies against SARS-CoV-2 has contributed to the managing strategies for the COVID-19 pandemic. This study aimed to investigate the performance of three high-throughput assays and one rapid lateral flow test relative to regulatory authorities' recommended criteria.METHODS: A total of 315 samples, including 150 pre-pandemic samples, 152 samples from SARS-CoV-2 RT-PCR positive individuals and 13 potentially cross-reactive samples were analysed with SARS-CoV-2 IgG (Abbott, Abbott Park, IL), Elecsys Anti-SARS-CoV-2 (Roche, Solna, Sweden), LIAISON SARS-CoV-2 S1/S2 IgG (DiaSorin, Saluggia, Italy) and 2019-nCOV IgG/IgM Rapid Test (Dynamiker Biotechnology Co., Tianjin, China).RESULTS: All assays performed with a high level of specificity ranging from 96.7% to 99.3%. Sensitivity differed more between the assays, Roche exhibiting the highest sensitivity of 98.7%. The corresponding figures for Abbott, DiaSorin and Dynamiker Biotechnology were 80.9%, 89.0% and 72.4%, respectively.CONCLUSIONS: The results of the evaluated SARS-CoV-2 assays vary considerably, as well as their ability to fulfil the performance criteria proposed by regulatory authorities. Introduction into clinical use in low-prevalent settings, should, therefore, be made with caution.
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| 4. |
- Pattison-Granberg, Johanna, 1973-
(författare)
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Physiological regulation of the high-affinity phosphate uptake system in the yeast Saccharomyces cerevisiae
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Yeast cells can be found in a wide variety of environments, demonstrating that these cells are capable of adapting to changes in the external milieu. Inorganic phosphate (Pi) is an essential nutrient for all organisms and Saccharomyces cerevisiae cells take up phosphate from the external environment via two different systems, i.e., a high-affinity system consisting of the Pho84 and Pho89 permeases and a low-affinity system composed of the Pho87, Pho90 and Pho91 permeases. Expression of the Pho84 and Pho89 permeases is regulated in response to the extracellular concentration of Pi, whereas the low-affinity system is thought to be expressed constitutively. The Pho84 permease couples phosphate uptake with protons and has an acidic pH optimum. In contrast, Pho89 is a cation-coupled phosphate transporter with a preference for sodium ions and an alkaline pH optimum.In the present thesis the regulation of the two high-affinity phosphate transporters in response to alterations in the external concentration of Pi has been examined. The Pho84 permease is the major supplier of phosphate under Pi-limiting conditions, whereas the Pho89 permease plays only a minor role under such conditions. Instead, Pho89 is proposed to be involved in supplying phosphate to the cells in different stressful situations. In a strain from which all of the phosphate transporters except Pho89 have been deleted, this protein is up-regulated sufficiently to sustain cell growth under both high- and low-phosphate conditions even in the presence of an acidic environment.In addition to being regulated on the transcriptional level, Pho84 is also regulated post-translationally and is in response to Pi addition or depletion internalised and sorted to the vacuole for degradation. This post-translational regulation is independent of the PHO pathway that mediates transcriptional regulation.
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| 7. |
- Petersson, Annika, et al.
(författare)
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Differences in SARS-CoV-2 antibodies depending on age, blood group, and sex in a Swedish blood donor cohort
- 2024
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Taylor & Francis. - 0036-5513 .- 1502-7686.
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to describe differences in prevalence and the long-term presence of nucleocapsid antibodies (N-antibodies) elicited by SARS-CoV-2 infection in a Swedish blood donor population not subjected to lockdown. We tested 20,651 blood donor samples for nucleocapsid antibodies from the beginning of March 2020 and 27 months onwards using the Roche Elecsys Anti-SARS-CoV-2 assay. The proportion of positive SARS-CoV-2 antibody samples was determined each week. After the exclusions of one-time donors and subjects with incomplete data, 19,726 samples from 4003 donors remained. Differences in antibody prevalences stratified for age, sex, and blood groups (ABO and RhD) were determined, as well as antibody loss and recovery. Lower antibody prevalence was seen for older donors, blood group AB, and RhD-negative subjects. A significant decrease in antibody titer between the first and the second antibody-positive donation was seen for the whole study group, females, older subjects, blood group O, AB, and RhD-positive subjects. The titer waned below the detection limit in 60 (3.0%) of 1983 N-antibody-positive donors, and for 18 of these donors, a second episode with antibodies was detected. We showed that N-antibodies persist for months or years and that surprisingly few antibody-positive donors lost their antibodies. We also conclude that antibody prevalence in a Swedish population never subject to lockdown did not apparently differ from populations that were subject to stricter regulations.
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| 9. |
- Zvyagilskaya, Renata A., et al.
(författare)
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Characterization of the Pho89 phosphate transporter by functional hyperexpression in Saccharomyces cerevisiae
- 2008
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Ingår i: FEMS yeast research (Print). - : Oxford University Press. - 1567-1356 .- 1567-1364. ; 8:5, s. 685-696
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Tidskriftsartikel (refereegranskat)abstract
- The Na(+)-coupled, high-affinity Pho89 plasma membrane phosphate transporter in Saccharomyces cerevisiae has so far been difficult to study because of its low activity and special properties. In this study, we have used a pho84Deltapho87Deltapho90Deltapho91Delta quadruple deletion strain of S. cerevisiae devoid of all transporter genes specific for inorganic phosphate, except for PHO89, to functionally characterize Pho89 under conditions where its expression is hyperstimulated. Under these conditions, the Pho89 protein is strongly upregulated and is the sole high-capacity phosphate transporter sustaining cellular acquisition of inorganic phosphate. Even if Pho89 is synthesized in cells grown at pH 4.5-8.0, the transporter is functionally active under alkaline conditions only, with a K(m) value reflecting high-affinity properties of the transporter and with a transport rate about 100-fold higher than that of the protein in a wild-type strain. Even under these hyperexpressive conditions, Pho89 is unable to sense and signal extracellular phosphate levels. In cells grown at pH 8.0, Pho89-mediated phosphate uptake at alkaline pH is cation-dependent with a strong activation by Na(+) ions and sensitivity to carbonyl cyanide m-chlorophenylhydrazone. The contribution of H(+)- and Na(+)-coupled phosphate transport systems in wild-type cells grown at different pH values was quantified. The contribution of the Na(+)-coupled transport system to the total cellular phosphate uptake activity increases progressively with increasing pH.
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