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Search Results: 1 - 10 of 251 matches for " Sofie Ahlin "
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No Evidence for a Role of Adipose Tissue-Derived Serum Amyloid A in the Development of Insulin Resistance or Obesity-Related Inflammation in hSAA1+/? Transgenic Mice
Sofie Ahlin, Maja Olsson, Bob Olsson, Per-Arne Svensson, Kajsa Sj?holm
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0072204
Abstract: Obesity is associated with a low-grade inflammation including moderately increased serum levels of the acute phase protein serum amyloid A (SAA). In obesity, SAA is mainly produced from adipose tissue and serum levels of SAA are associated with insulin resistance. SAA has been described as a chemoattractant for inflammatory cells and adipose tissue from obese individuals contains increased numbers of macrophages. However, whether adipose tissue-derived SAA can have a direct impact on macrophage infiltration in adipose tissue or the development of insulin resistance is unknown. The aim of this study was to investigate the effects of adipose tissue-derived SAA1 on the development of insulin resistance and obesity-related inflammation. We have previously established a transgenic mouse model expressing human SAA1 in the adipose tissue. For this report, hSAA1+/? transgenic mice and wild type mice were fed with a high fat diet or normal chow. Effects of hSAA1 on glucose metabolism were assessed using an oral glucose tolerance test. Real-time PCR was used to measure the mRNA levels of macrophage markers and genes related to insulin sensitivity in adipose tissue. Cytokines during inflammation were analyzed using a Proinflammatory 7-plex Assay. We found similar insulin and glucose levels in hSAA1 mice and wt controls during an oral glucose tolerance test and no decrease in mRNA levels of genes related to insulin sensitivity in adipose tissue in neither male nor female hSAA1 animals. Furthermore, serum levels of proinflammatory cytokines and mRNA levels of macrophage markers in adipose tissue were not increased in hSAA1 mice. Hence, in this model we find no evidence that adipose tissue-derived hSAA1 influences the development of insulin resistance or obesity-related inflammation.
Endogenous Acute Phase Serum Amyloid A Lacks Pro-Inflammatory Activity, Contrasting the Two Recombinant Variants That Activate Human Neutrophils through Different Receptors
Karin Christenson,Lena Bj?rkman,Sofie Ahlin,Maja Olsson,Kajsa Sj?holm,Anna Karlsson,Johan Bylund
Frontiers in Immunology , 2013, DOI: 10.3389/fimmu.2013.00092
Abstract: Most notable among the acute phase proteins is serum amyloid A (SAA), levels of which can increase 1000-fold during infections, aseptic inflammation, and/or trauma. Chronically elevated SAA levels are associated with a wide variety of pathological conditions, including obesity and rheumatic diseases. Using a recombinant hybrid of the two human SAA isoforms (SAA1 and 2) that does not exist in vivo, numerous in vitro studies have given rise to the notion that acute phase SAA is a pro-inflammatory molecule with cytokine-like properties. It is however unclear whether endogenous acute phase SAA per se mediates pro-inflammatory effects. We tested this in samples from patients with inflammatory arthritis and in a transgenic mouse model that expresses human SAA1. Endogenous human SAA did not drive production of pro-inflammatory IL-8/KC in either of these settings. Human neutrophils derived from arthritis patients displayed no signs of activation, despite being exposed to severely elevated SAA levels in circulation, and SAA-rich sera also failed to activate cells in vitro. In contrast, two recombinant SAA variants (the hybrid SAA and SAA1) both activated human neutrophils, inducing L-selectin shedding, production of reactive oxygen species, and production of IL-8. The hybrid SAA was approximately 100-fold more potent than recombinant SAA1. Recombinant hybrid SAA and SAA1 activated neutrophils through different receptors, with recombinant SAA1 being a ligand for formyl peptide receptor 2 (FPR2). We conclude that even though recombinant SAAs can be valuable tools for studying neutrophil activation, they do not reflect the nature of the endogenous protein.
Establishment of a Transgenic Mouse Model Specifically Expressing Human Serum Amyloid A in Adipose Tissue
Maja Olsson,Sofie Ahlin,Bob Olsson,Per-Arne Svensson,Marcus St?hlman,Jan Borén,Lena M. S. Carlsson,Kajsa Sj?holm
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0019609
Abstract: Obesity and obesity co-morbidities are associated with a low grade inflammation and elevated serum levels of acute phase proteins, including serum amyloid A (SAA). In the non-acute phase in humans, adipocytes are major producers of SAA but the function of adipocyte-derived SAA is unknown. To clarify the role of adipocyte-derived SAA, a transgenic mouse model expressing human SAA1 (hSAA) in adipocytes was established. hSAA expression was analysed using real-time PCR analysis. Male animals were challenged with a high fat (HF) diet. Plasma samples were subjected to fast protein liquid chromatography (FPLC) separation. hSAA, cholesterol and triglyceride content were measured in plasma and in FPLC fractions. Real-time PCR analysis confirmed an adipose tissue-specific hSAA gene expression. Moreover, the hSAA gene expression was not influenced by HF diet. However, hSAA plasma levels in HF fed animals (37.7±4.0 μg/mL, n = 7) were increased compared to those in normal chow fed animals (4.8±0.5 μg/mL, n = 10; p<0.001), and plasma levels in the two groups were in the same ranges as in obese and lean human subjects, respectively. In FPLC separated plasma samples, the concentration of hSAA peaked in high-density lipoprotein (HDL) containing fractions. In addition, cholesterol distribution over the different lipoprotein subfractions as assessed by FPLC analysis was similar within the two experimental groups. The established transgenic mouse model demonstrates that adipose tissue produced hSAA enters the circulation, resulting in elevated plasma levels of hSAA. This new model will enable further studies of metabolic effects of adipose tissue-derived SAA.
Adipose Tissue-Derived Human Serum Amyloid A Does Not Affect Atherosclerotic Lesion Area in hSAA1+/?/ApoE?/? Mice
Sofie Ahlin, Maja Olsson, Anna S. Wilhelmson, Kristina Sk?lén, Jan Borén, Lena M. S. Carlsson, Per-Arne Svensson, Kajsa Sj?holm
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0095468
Abstract: Chronically elevated serum levels of serum amyloid A (SAA) are linked to increased risk of cardiovascular disease. However, whether SAA is directly involved in atherosclerosis development is still not known. The aim of this study was to investigate the effects of adipose tissue-derived human SAA on atherosclerosis in mice. hSAA1+/? transgenic mice (hSAA1 mice) with a specific expression of human SAA1 in adipose tissue were bred with ApoE-deficient mice. The hSAA1 mice and their wild type (wt) littermates were fed normal chow for 35 weeks. At the end of the experiment, the mice were euthanized and blood, gonadal adipose tissue and aortas were collected. Plasma levels of SAA, cholesterol and triglycerides were measured. Atherosclerotic lesion areas were analyzed in the aortic arch, the thoracic aorta and the abdominal aorta in en face preparations of aorta stained with Sudan IV. The human SAA protein was present in plasma from hSAA1 mice but undetectable in wt mice. Similar plasma levels of cholesterol and triglycerides were observed in hSAA1 mice and their wt controls. There were no differences in atherosclerotic lesion areas in any sections of the aorta in hSAA1 mice compared to wt mice. In conclusion, our data suggest that adipose tissue-derived human SAA does not influence atherosclerosis development in mice.
Respiratory Physiotherapy in a Web Browser, Feasibility Study  [PDF]
Matevz Leskovsek, Martin Lasi?, Dragomira Ahlin
Open Journal of Respiratory Diseases (OJRD) , 2013, DOI: 10.4236/ojrd.2013.34023
Abstract:

In this paper, feasibility of web based breathing exercises for respiratory rehabilitation is examined. A system included visual guidance in a web browser and a microphone equipped headset for biofeedback and interaction. Feasibility was assessed in a controlled environment on 34 subjects with anxiety disorders that were not offered any help from the personnel. Weak points of comprehensibility were identified as applying headset (21%) and adhering to breathing exercises instructions (7%). No adverse events were identified. Design flaws that correlated with poor user’s experience were 1) the unpleasant feelings induced by watching the computer screen (21%) and 2) ease/difficulty of physically applying headset (14%). We conclude that conducting breathing exercises by using an acoustic microphone and a web browser is feasible and should be further researched. Additionally we conclude that audio feedback might be more pleasant to some people.

The Large Scale Geometry of Nilpotent-by-Cyclic Groups
Ashley Reiter Ahlin
Mathematics , 2005,
Abstract: A nonpolycyclic nilpotent-by-cyclic group Gamma can be expressed as the HNN extension of a finitely-generated nilpotent group N. The first main result is that quasi-isometric nilpotent-by-cyclic groups are HNN extensions of quasi-isometric nilpotent groups. The nonsurjective injection defining such an extension induces an injective endomorphism phi of the Lie algebra g associated to the Lie group in which N is a lattice. A normal form for automorphisms of nilpotent Lie algebras--permuted absolute Jordan form-- is defined and conjectured to be a quasi-isometry invariant. We show that if phi, theta are endomorphisms of lattices in a fixed Carnot group G, and if the induced automorphisms of g have the same permuted absolute Jordan form, then Gamma_phi and Gamma_theta are quasi-isometric. Two quasi-isometry invariants are also found: the set of ``divergence rates'' of vertical flow lines: D_phi the ``growth spaces'': g_n subset g These do not establish that permuted absolute Jordan form is a quasi-isometry invariant, although they are major steps toward that conjecture. Furthermore, the quasi-isometric rigidity of finitely-presented nilpotent-by-cyclic groups is proven: any finitely-presented group quasi-isometric to a nonpolycyclic nilpotent-by-cyclic group is (virtually-nilpotent)-by-cyclic.
Time History Forced Response in Nonlinear Mechanical Systems
Ahlin K.,Josefsson A.,Magnevall M.
MATEC Web of Conferences , 2012, DOI: 10.1051/matecconf/20120103002
Abstract: A formulation of a digital filter method for computing the forced response of a linear MDOF mechanical system is proposed. It is shown how aliasing error effects can be avoided at the expense of a bias error. The bias error is however completely known and it is system independent, as it only depends on the sampling frequency used. The mechanical system is described by its modal parameters, poles and residues. The method is extended to include non-linear elements. A toolbox in MATLAB has been created where nonlinear elements with and without memory can be treated, as well as system described by coupled non-linear equations.
Altru stisch ambtenaar of hero sch genie? Het gepropageerde beeld van provinciale en academische directeurs van bacteriologische laboratoria in Belgi (ca. 1900-1940)
Sofie Onghena
Studium : Tijdschrift voor Wetenschaps- en Universiteits-Geschiedenis , 2009,
Abstract: Altruistic public servant or heroic genius? The propagated image of provincial and academic directors of bacteriological laboratories in Belgium (ca. 1900-1940) At the end of the nineteenth century provincial bacteriological institutes were established in Belgium – in Liège, Mons, Namur and Brussels – in order to combat epidemics, to promote preventive medicine and to pursue the successful research of Louis Pasteur and Robert Koch. Similar laboratories existed at the universities of Ghent, Louvain and Brussels. The image building played an important role for both kinds of institutes, as bacteriology in pioneering phase had to be publicly confirmed as a new, valuable discipline. However, the directors of provincial and academic institutes – with the same academic training though – were awarded with different qualities at their jubilees, fitting with the purposes and the self-image of their respective institutions, either provincial authorities or universities. The image of academic directors was guided by academic decorum: Emile van Ermengem, Edmond Destrée and Joseph Denys were represented as savants, solely devoted to pure science and paternally educating young researchers, notwithstanding the fact that their laboratories had humanitarian merits as well. On the other hand, the discourse on the first provincial directors – Ernest Malvoz, Martin Herman, Achille Haibe – emphasized their altruistic commitment and their solid work for the provincial government. Jules Bordet, internationally rewarded scientist, professor and provincial director of the Pasteur Institute in Brussels, was celebrated with both sorts of discourses.
REVIEW: Cosmopolitanism: Ideals and Realities
Sofie Dreef
Amsterdam Law Forum , 2012,
Abstract: Book review of 'Cosmopolitanism: Ideals and Realities' by David Held.
Editorial
Sofie Dreef
Amsterdam Law Forum , 2011,
Abstract: The topic of Amsterdam Law Forum’s last thematic number is ‘Legal Perspectives on Gender and Sexual Equality’.
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