| 1. |
- Hammarsten, Ola, et al.
(författare)
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Evaluation of a Sensitive Copeptin Assay for Clinical Measurement
- 2012
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Ingår i: The Open Clinical Chemistry Journal. - : Bentham Science Publishers Ltd.. - 2588-7785 .- 1874-2416. ; 5:1, s. 21-26
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Background: Copeptin, a marker of vasopressin production, has been introduced for earlier diagnosis of acute myocardial infarction and other clinical emergencies. We evaluated the analytical performance of a new generation copeptin assay in an inter-laboratory trial. Methods: Precision, linearity range, carry-over contamination, the limit of blank and an inter-laboratory comparison trial for the copeptin US KRYPTOR assay were performed on the B·R·A·H·M·S KRYPTOR compact PLUS. Results: The intra-assay imprecision (CVs) was 12.6–2.2% and total imprecision over five days was 12.3-4.3% between 3.1 and 18.2 pmol/L. The assay had excellent linearity between 7-222 pmol/L. The limit of blank was 2.5 pmol/L and the limit of detection was 3.2 pmol/L, but was dependent on the analyte-free material used. No significant difference between sample type, such as serum or different types of plasma or reagent lots, was noted. The copeptin results remained unchanged upon five repeated freeze-thaw cycles. A set of patient samples with a mean copeptin concentration of 2.1-61 pmol/L run at two separate sites showed close correlation (r2=0.99, slope=1.01, intercept=0.35), indicating comparable results across laboratories. Conclusion: The new ultrasensitive copeptin KRYPTOR assay shows excellent inter-lab precision, opening up the possibility for international guidelines to exclude acute myocardial infarction.
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| 2. |
- Muslimovic, Aida, et al.
(författare)
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Calibrators for Clinical Measurements of Phosphorylated H2AX in Patient Cells by Flow Cytometry
- 2012
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Ingår i: The Open Clinical Chemistry Journal. - : Bentham Science Publishers Ltd.. - 2588-7785 .- 1874-2416. ; 5:1, s. 33-39
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Agents that induce DNA double-strand breaks (DSBs), such as ionizing radiation, are frequently used in cancer therapy. H2AX is rapidly phosphorylated in response to DSBs and serves as a way to measure the extent of DSBs induced in patient cells. We have previously reported a flow cytometry-based method for measuring H2AX phosphorylation in pa-tient cells undergoing radiotherapy. To be able to implement measurement of H2AX phosphorylation in clinical practice, we have characterized calibrators for the flow cytometry analysis based on phosphopeptide-coated beads and fixed cells. The calibrator beads and fixed cells lost less than 11% of the signal after storage for 40 days under optimal conditions and were able to correct for day-to-day variation in method performance.
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| 3. |
- Hjelmevoll, Stig Ove, et al.
(författare)
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Appropriate Time for Test-of-Cure when Diagnosing Gonorrhoea with a Nucleic Acid Amplification Test
- 2012
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Ingår i: Acta Dermato-Venereologica. - Uppsala : Acta Dermato-Venereologica. - 0001-5555 .- 1651-2057. ; 92:3, s. 316-319
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Tidskriftsartikel (refereegranskat)abstract
- Culture is commonly regarded as the gold standard for diagnosis of Neisseria gonorrhoeae. However, nucleic acid amplification tests (NAATs) have rapidly replaced culture for diagnostics in many settings. The aim of the present study was to investigate the appropriate time for test-of-cure (TOC) when NAATs are used for diagnosis of gonorrhoea. In total, 30 patients (28 men and 2 women) provided urethral, cervical, rectal or pharyngeal specimens for TOC. All included patients, except one who did not return for second TOC before day 19, tested negative within 2 weeks after treatment with cefixime 400 mg x 1. Antimicrobial susceptibility testing showed that 68% of the culture-positive strains were resistant to ciprofloxacin. Thus, the recommended empirical treatment with ciprofloxacin in Norway should be changed immediately. TOC can be performed 2 weeks after treatment when NAATs are used for diagnosis of gonorrhoea.
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| 4. |
- Nasir, Waqas, et al.
(författare)
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Lewis histo-blood group alpha1,3/alpha1,4 fucose residues may both mediate binding to GII.4 noroviruses
- 2012
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Ingår i: Glycobiology. - : Oxford University Press (OUP). - 0959-6658 .- 1460-2423. ; 22:9, s. 1163-72
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Tidskriftsartikel (refereegranskat)abstract
- Human noroviruses cause recurrent epidemics of gastroenteritis known to be dominated by the clinically important GII.4 genotype which recognizes human Secretor gene-dependent ABH histo-blood group antigens (HBGAs) as attachment factors. There is increasing evidence that GII.4 noroviruses have undergone evolutionary changes to recognize Lewis antigens and non-Secretor saliva. In this study, we have investigated the possibilities of the Lewis alpha1,3/alpha1,4 fucoses as mediators of binding of GII.4 noroviruses to Lewis antigens. The study was carried out using molecular dynamics simulations of Lewis type-1 and type-2 chain HBGAs in complex with VA387 P domain dimers in explicit water. Based on the computer simulations, we suggest the possibility of two receptor binding modes for Lewis HBGAs: the "Secretor pose" with the Secretor Fucalpha1,2 in the binding site and the "Lewis pose" with the Lewis Fucalpha1,3/alpha1,4 residues in the binding site. This was further supported by an extensive GlyVicinity analysis of the Protein Data Bank with respect to the occurrence of the Lewis and Secretor poses in complexes of Lewis antigens with lectins and antibodies as well as GII norovirus strains. The Lewis pose can also explain the interactions of GII.4 norovirus strains with Le(x) and SLe(x) structures. Moreover, the present model suggests binding of complex branched polysaccharides, with the Lewis antigens at the nonreducing end, to P domain dimers of GII.4 strains. Our results are relevant for understanding the evolution of norovirus binding specificities and for in silico design of future antiviral therapeutics.
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| 5. |
- Karlsson, Roger, 1975, et al.
(författare)
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Strain-level typing and identification of bacteria using mass spectrometry-based proteomics.
- 2012
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Ingår i: Journal of proteome research. - : American Chemical Society (ACS). - 1535-3907 .- 1535-3893. ; 11:5, s. 2710-20
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Tidskriftsartikel (refereegranskat)abstract
- Because of the alarming expansion in the diversity and occurrence of bacteria displaying virulence and resistance to antimicrobial agents, it is increasingly important to be able to detect these microorganisms and to differentiate and identify closely related species, as well as different strains of a given species. In this study, a mass spectrometry proteomics approach is applied, exploiting lipid-based protein immobilization (LPI), wherein intact bacterial cells are bound, via membrane-gold interactions, within a FlowCell. The bound cells are subjected to enzymatic digestion for the generation of peptides, which are subsequently identified, using LC-MS. Following database matching, strain-specific peptides are used for subspecies-level discrimination. The method is shown to enable a reliable typing and identification of closely related strains of the same bacterial species, herein illustrated for Helicobacter pylori .
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| 6. |
- Nilsson-Ehle, Herman, 1950, et al.
(författare)
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Vitaminer och spårämnen.
- 2012
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Ingår i: Laurells Klinisk kemi i praktisk medicin. - 2012 - 9., [rev. och utök.] uppl. / redaktion: Peter Nilsson-Ehle, Maria Berggren Söderlund, Elvar Theodorsson ; redaktionskommitté: Charlotte Becker, Kjell Grankvist, Anders Grubb, Göran Lindstedt, Per Simonsson.. - Lund : Studentlitteratur AB. - 9789144047874
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Bokkapitel (refereegranskat)
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| 7. |
- Rosén, Christoffer, 1986, et al.
(författare)
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Cerebrospinal fluid profiles of amyloid β-related biomarkers in Alzheimer's disease.
- 2012
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Ingår i: Neuromolecular medicine. - : Springer Science and Business Media LLC. - 1559-1174 .- 1535-1084. ; 14:1, s. 65-73
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Tidskriftsartikel (refereegranskat)abstract
- The amyloid cascade hypothesis on the pathogenesis of Alzheimer's disease (AD) states that amyloid β (Aβ) accumulation in the brain is a key factor that initiates the neurodegenerative process. Aβ is generated from amyloid precursor protein (APP) through sequential cleavages by BACE1 (the major β-secretase in the brain) and γ-secretase. The purpose of this study was to characterize APP metabolism in vivo in AD patients versus cognitively healthy subjects by examining alterations in cerebrospinal fluid (CSF) biomarkers. We measured BACE1 activity and concentrations of α- and β-cleaved soluble APP (sAPPα and sAPPβ, respectively) and Aβ40 in CSF, biomarkers that all reflect the metabolism of APP, in 75 AD patients and 65 cognitively healthy controls. These analytes were also applied in a multivariate model to determine whether they provided any added diagnostic value to the core CSF AD biomarkers Aβ42, T-tau, and P-tau. We found no significant differences in BACE1 activity or sAPPα, sAPPβ, and Aβ40 concentrations between AD patients and controls. A multivariate model created with all analytes did not improve the separation of AD patients from controls compared with using the core AD biomarkers alone, highlighting the strong diagnostic performance of Aβ42, T-tau, and P-tau for AD. However, AD patients in advanced clinical stage, as determined by low MMSE score (≤20), had lower BACE1 activity and sAPPα, sAPPβ, and Aβ40 concentrations than patients with higher MMSE score, suggesting that these markers may be related to the severity of the disease.
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| 8. |
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| 9. |
- Bally, Marta, 1981, et al.
(författare)
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Interaction of virions with membrane glycolipids
- 2012
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Ingår i: Physical Biology. - : IOP Publishing. - 1478-3967 .- 1478-3975. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- Cellular membranes contain various lipids including glycolipids (GLs). The hydrophilic head groups of GLs extend from the membrane into the aqueous environment outside the cell where they act as recognition sites for specific interactions. The first steps of interaction of virions with cells often include contacts with GLs. To clarify the details of such contacts, we have used the total internal reflection fluorescence microscopy to explore the interaction of individual unlabelled virus-like particles (or, more specifically, norovirus protein capsids), which are firmly bound to a lipid bilayer, and fluorescent vesicles containing glycosphingolipids (these lipids form a subclass of GLs). The corresponding binding kinetics were earlier found to be kinetically limited, while the detachment kinetics were logarithmic over a wide range of time. Here, the detachment rate is observed to dramatically decrease with increasing concentration of glycosphingolipids from 1% to 8%. This effect has been analytically explained by using a generic model describing the statistics of bonds in the contact area between a virion and a lipid membrane. Among other factors, the model takes the formation of GL domains into account. Our analysis indicates that in the system under consideration, such domains, if present, have a characteristic size smaller than the contact area between the vesicle and the virus-like particle.
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| 10. |
- Bucardo, Filemon, et al.
(författare)
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Susceptibility of Children to Sapovirus Infections, Nicaragua, 2005–2006
- 2012
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Ingår i: Emerging Infectious Diseases. - Atlanta, GA, USA : U.S. Department of Health and Human Services * Centers for Disease Control and Prevention. - 1080-6040 .- 1080-6059. ; 18:11, s. 1875-1878
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Tidskriftsartikel (refereegranskat)abstract
- We describe the genetic diversity of sapovirus (SaV) in children in Nicaragua and investigate the role of host genetic factors and susceptibility to SaV infections. Our results indicate that neither ABO blood group, Lewis phenotype, nor secretor status affects susceptibility to SaV infection in Nicaragua.
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