Publications by authors named "Sveinn Gudmundsson"

Unlabelled: Platelet granules contain a diverse group of proteins. Upon activation and during storage, platelets release a number of proteins into the circulation or supernatant of stored platelet concentrate (PC). The aim of this work was to investigate the effect of pathogen inactivation (PI) on a selection of proteins released in stored platelets.

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Rheumatoid arthritis (RA) is a chronic multisystem disease with a complex immunopathology. Its inflammatory state is dominated by pro-inflammatory cytokines such as TNFα and activated Th1/Th17. Only proportion of patients achieve clinical remission despite potent biologics targeting these pathways.

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Objectives: To estimate the frequency of iron deficiency (ID) and anaemia in blood donors in Iceland and the impact of serum ferritin (SF) testing policy change.

Background: Blood donations contribute to ID and/or anaemia in whole blood donors (WBD). SF may be used to monitor blood donor iron stores.

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A detailed understanding of the antibody response against SARS-CoV-2 is of high importance, especially with the emergence of novel vaccines. A multiplex-based assay, analyzing IgG, IgM, and IgA antibodies against the receptor binding domain (RBD), spike 1 (S1), and nucleocapsid proteins of the SARS-CoV-2 virus was set up. The multiplex-based analysis was calibrated against the Elecsys Anti-SARS-CoV-2 assay on a Roche Cobas instrument, using positive and negative samples.

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Background: Several outbreaks of highly pathogenic avian influenza (HPAI) caused by influenza A virus of subtype H5N8 have been reported in wild birds and poultry in Europe during autumn 2020. Norway is one of the few countries in Europe that had not previously detected HPAI virus, despite widespread active monitoring of both domestic and wild birds since 2005.

Results: We report detection of HPAI virus subtype H5N8 in a wild pink-footed goose (Anser brachyrhynchus), and several other geese, ducks and a gull, from south-western Norway in November and December 2020.

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The purpose of this research is to test the ex-post cost structure effects in horizontal mergers and acquisitions (M&A). Our proposed methodology quantifies cost structure effects empirically to inform competition policy around M&As in the airline industry. The results show that horizontal M&As involving unprofitable firms significantly reduce variable costs and increase fixed costs ex-post.

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Background: Rhesus D (RhD) incompatibility is still the most important cause of hemolytic disease of the fetus and newborn (HDFN) worldwide. The aim of this study was to investigate the incidence, causes, and consequences of anti-D alloimmunizations in pregnancy in Iceland, prior to implementation of targeted routine antenatal anti-D prophylaxis (RAADP) in 2018.

Study Design And Methods: This was a nation-wide cohort study of 130 pregnancies affected by RhD alloimmunization in Iceland in the period from 1996 through 2015.

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Background: The risk of bacterial contamination and the deterioration of platelet (PLT) quality limit the shelf-life of platelet concentrates (PCs). The INTERCEPT pathogen inactivation system reduces the risk of pathogen transmission by inhibiting nucleic acid replication using a combination of a photo-reactive compound and UVA illumination. The goal of this study was to investigate the effects the INTERCEPT system has on the PLT metabolome and metabolic activity.

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Background: To reduce the risk of transfusion transmission infection, nucleic acid targeted methods have been developed to inactivate pathogens in PCs. miRNAs have been shown to play an important role in platelet function, and changes in the abundance of specific miRNAs during storage have been observed, as have perturbation effects related to pathogen inactivation (PI) methods. The aim of this work was to investigate the effects of PI on selected miRNAs during storage.

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Platelets (PLTs) deteriorate over time when stored within blood banks through a biological process known as PLT storage lesion (PSL). Here, we describe the refinement of the biochemical model of PLT metabolism, iAT-PLT-636, and its application to describe and investigate changes in metabolism during PLT storage. Changes in extracellular acetate and citrate were measured in buffy coat and apheresis PLT units over 10 days of storage in the PLT additive solution T-Sol.

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Fetal globin genes are transcriptionally silenced during embryogenesis through hemoglobin switching. Strategies to derepress fetal globin expression in the adult could alleviate symptoms in sickle cell disease and β-thalassemia. We identified a zinc-finger protein, pogo transposable element with zinc-finger domain (POGZ), expressed in hematopoietic progenitor cells.

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The temperature dependence of biological processes has been studied at the levels of individual biochemical reactions and organism physiology ( basal metabolic rates) but has not been examined at the metabolic network level. Here, we used a systems biology approach to characterize the temperature dependence of the human red blood cell (RBC) metabolic network between 4 and 37 °C through absolutely quantified exo- and endometabolomics data. We used an Arrhenius-type model () to describe how the rate of a biochemical process changes with every 10 °C change in temperature.

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Background: Red blood cell (RBC) alloimmunization during pregnancy is still a major problem. Historically, anti-D antibodies are most likely to cause severe hemolysis, but other antibodies are also important. In Iceland, postnatal RhIg prophylaxis was implemented in 1969, universal RBC antibody screening was implemented in 1978, but antenatal RhIg prophylaxis is not yet routine.

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Background: Alternate sugar metabolism during red blood cell (RBC) storage is not well understood. Here we report fructose and mannose metabolism in RBCs during cold storage in SAGM and the impact that these monosaccharides have on metabolic biomarkers of RBC storage lesion.

Study Design And Methods: RBCs were stored in SAGM containing uniformly labeled C-fructose or C-mannose at 9 or 18 mmol/L concentration for 25 days.

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Metabolomic investigations of packed red blood cells (RBCs) stored under refrigerated conditions in saline adenine glucose mannitol (SAGM) additives have revealed the presence of 3 distinct metabolic phases, occurring on days 0-10, 10-18, and after day 18 of storage. Here we used receiving operating characteristics curve analysis to identify biomarkers that can differentiate between the 3 metabolic states. We first recruited 24 donors and analyzed 308 samples coming from RBC concentrates stored in SAGM and additive solution 3.

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Background: Red blood cells (RBCs) are routinely stored and transfused worldwide. Recently, metabolomics have shown that RBCs experience a three-phase metabolic decay process during storage, resulting in the definition of three distinct metabolic phenotypes, occurring between Days 1 and 10, 11 and 17, and 18 and 46. Here we use metabolomics and stable isotope labeling analysis to study adenine metabolism in RBCs.

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Background: Demographic information of blood donors is important to formulate strategies for recruitment and maintenance of the donor group. Factors like aging population, increasingly advanced medical treatments, and growing safety initiatives to protect donors and recipients of blood components are likely to affect the size of the donor group in the future. The purpose of this study was to determine the size of the donor group in Iceland and describe the demographic and donation characteristics.

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Background: There has been interest in determining whether older red blood cell (RBC) units have negative clinical effects. Numerous observational studies have shown that older RBC units are an independent factor for patient mortality. However, recently published randomized clinical trials have shown no difference of clinical outcome for patients receiving old or fresh RBCs.

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Background: Platelet concentrates (PCs) can be prepared using three methods: platelet (PLT)-rich plasma, apheresis, and buffy coat. The aim of this study was to obtain a comprehensive data set that describes metabolism of buffy coat-derived PLTs during storage and to compare it with a previously published parallel data set obtained for apheresis-derived PLTs.

Study Design And Methods: During storage we measured more than 150 variables in 8 PLT units, prepared by the buffy coat method.

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Background: Platelet (PLT) concentrates are routinely stored for 5 to 7 days. During storage they exhibit what has been termed PLT storage lesion (PSL), which is evident by a loss of hemostatic function when transfused into patients. The overall goal of this study was to obtain a comprehensive data set describing PLT metabolism during storage.

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Introduction: Due to potential risk of blood transfusions, clinical guidelines emphasize restrictive use of blood components. However, numerous studies indicate that adherence to guidelines is often less than optimal. Furthermore, information regarding use of blood transfusion in intensive care units (ICUs) and compliance to clinical guidelines is lacking.

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Objectives: The aim of the present study was to evaluate whether certain HLA antigens were risk factors for developing sarcoid arthritis and whether HLA antigens appear to account for the phenotype and the resolution of the arthritis condition in an unselected nationwide cohort.

Methods: The Icelandic Sarcoidosis Study (ISS) contains all tissue-verified cases of sarcoidosis in Iceland since 1981. Of a total of 234 cases, 39 patients were identified with arthritis and of those 36 delivered a biosample for the study.

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Objective: The authors aimed to investigate the incidence and outcomes of acute upper gastrointestinal bleeding (AUGIB) and to examine the role of drugs potentially associated with AUGIB.

Methods: The study was prospective, population-based and consisted of all patients who underwent upper gastrointestinal endoscopy (UGE), during the year of 2010 at the National University Hospital of Iceland. Drug intake of NSAIDs, low-dose aspirin (LDA), warfarin, SSRIs and bisphosphonates prior to GIB was prospectively registered and also checked in a Pharmaceutical Database covering all prescriptions in Iceland.

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Clinical treatment of orthopaedic tissue injuries often involves the use of titanium and titanium alloys with considerable research focusing on the surface modification of these materials. Chitosan, the partly deacetylated form of chitin, is one of the materials under investigation as surface coating for orthopaedic implants in order to improve osteo-integration and cellular attachment. In this study, we determined the effects of the degree of deacetylation (DD) of chitosan membranes on attachment, proliferation and osteogenic differentiation of MC3T3-E1 mouse preosteoblasts.

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An extraction method for intracellular metabolite profiling should ideally be able to recover the broadest possible range of metabolites present in a sample. However, the development of such methods is hampered by the diversity of the physico-chemical properties of metabolites as well as by the specific characteristics of samples and cells. In this study, we report the optimization of an UPLC-MS method for the metabolite analysis of platelet samples.

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