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Search Results: 1 - 10 of 4560 matches for " Joel Petersson "
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Lactobacillus reuteri Maintains a Functional Mucosal Barrier during DSS Treatment Despite Mucus Layer Dysfunction
Johan Dicksved, Olof Schreiber, Ben Willing, Joel Petersson, Sara Rang, Mia Phillipson, Lena Holm, Stefan Roos
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0046399
Abstract: Treatment with the probiotic bacterium Lactobacillus reuteri has been shown to prevent dextran sodium sulfate (DSS)-induced colitis in rats. This is partly due to reduced P-selectin-dependent leukocyte- and platelet-endothelial cell interactions, however, the mechanism behind this protective effect is still unknown. In the present study a combination of culture dependent and molecular based T-RFLP profiling was used to investigate the influence of L. reuteri on the colonic mucosal barrier of DSS treated rats. It was first demonstrated that the two colonic mucus layers of control animals had different bacterial community composition and that fewer bacteria resided in the firmly adherent layer. During DSS induced colitis, the number of bacteria in the inner firmly adherent mucus layer increased and bacterial composition of the two layers no longer differed. In addition, induction of colitis dramatically altered the microbial composition in both firmly and loosely adherent mucus layers. Despite protecting against colitis, treatment with L. reuteri did not improve the integrity of the mucus layer or prevent distortion of the mucus microbiota caused by DSS. However, L. reuteri decreased the bacterial translocation from the intestine to mesenteric lymph nodes during DSS treatment, which might be an important part of the mechanisms by which L. reuteri ameliorates DSS induced colitis.
iNOS-Dependent Increase in Colonic Mucus Thickness in DSS-Colitic Rats
Olof Schreiber, Joel Petersson, Tomas Waldén, David Ahl, Stellan Sandler, Mia Phillipson, Lena Holm
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0071843
Abstract: Aim To investigate colonic mucus thickness in vivo in health and during experimental inflammatory bowel disease. Methods Colitis was induced with 5% DSS in drinking water for 8 days prior to experiment, when the descending colonic mucosa of anesthetized rats was studied using intravital microscopy. Mucus thickness was measured with micropipettes attached to a micromanipulator. To assess the contributions of NOS and prostaglandins in the regulation of colonic mucus thickness, the non-selective NOS-inhibitor L-NNA (10 mg/kg bolus followed by 3 mg/kg/h), the selective iNOS-inhibitor L-NIL (10 mg/kg bolus followed by 3 mg/kg/h) and the non-selective COX-inhibitor diclofenac (5 mg/kg) were administered intravenously prior to experiment. To further investigate the role of iNOS in the regulation of colonic mucus thickness, iNOS ?/? mice were used. Results Colitic rats had a thicker firmly adherent mucus layer following 8 days of DSS treatment than untreated rats (88±2 μm vs 76±1 μm). During induction of colitis, the thickness of the colonic mucus layer initially decreased but was from day 3 significantly thicker than in untreated rats. Diclofenac reduced the mucus thickness similarly in colitic and untreated rats (?16±5 μm vs ?14±2 μm). While L-NNA had no effect on colonic mucus thickness in DSS or untreated controls (+3±2 μm vs +3±1 μm), L-NIL reduced the mucus thickness significantly more in colitic rats than in controls (?33±4 μm vs ?10±3 μm). The importance of iNOS in regulating the colonic mucus thickness was confirmed in iNOS?/? mice, which had thinner colonic mucus than wild-type mice (35±3 μm vs 50±2 μm, respectively). Furthermore, immunohistochemistry revealed increased levels of iNOS in the colonic surface epithelium following DSS treatment. Conclusion Both prostaglandins and nitric oxide regulate basal colonic mucus thickness. During onset of colitis, the thickness of the mucus layer is initially reduced followed by an iNOS mediated increase.
Demokrati, svenskl rarutbildning och m ngkulturalism
Margareta Petersson
Utbildning & Demokrati : Tidsskrift f?r Didaktik och Utbildningspolitik , 2003,
Abstract:
Multilepton and multiphoton signatures of supersymmetry at the LHC
Christoffer Petersson
Physics , 2014,
Abstract: Motivated by the absence of any clear signal of physics beyond the Standard Model at the LHC after Run I, we discuss one possible slight hint of new physics and one non-minimal extension of the Standard Model. In the first part we provide a tentative explanation of a small excess of multilepton events, observed by the CMS collaboration, by means of a simplified model of gauge mediated supersymmetry breaking. In the second part we discuss how the standard phenomenology of gauge mediation can be significantly modified if one makes the non-minimal assumption that supersymmetry is broken in more than one hidden sector. Such multiple hidden sector models involve light neutral fermions called pseudo-goldstini and, due to the extra decay steps they induce, where soft photons are emitted, these models give rise to multiphoton plus missing energy signatures. We discuss why the existing LHC searches are poorly sensitive to these model and we propose new searches designed to probe them.
High Temperature QCD and Dimensional Reduction
Bengt Petersson
Physics , 2000,
Abstract: In this talk I will first give a short discussion of some lattice results for QCD at finite temperature. I will then describe in some detail the technique of dimensional reduction, which in principle is a powerful technique to obtain results on the long distance properties of the quark-gluon plasma. Finally I will describe some new results, which test the technique in a simpler model, namely three dimensional gauge theory.
Disappearing charged tracks in association with displaced leptons from supersymmetry
Christoffer Petersson
Physics , 2014,
Abstract: In this note we discuss a characteristic collider signature of models of gauge mediated supersymmetry breaking in which the selectron and smuon are mass-degenerate co-NLSP. In these models, all processes involving superpartners give rise to two NLSP selectrons or smuons, each of which subsequently decays to a nearly massless LSP gravitino and an electron or a muon. In a large region of the parameter space, the NLSPs travel macroscopic distances, of the order 0.1-1000 mm, before they decay. Hence, these models give rise to collider signatures involving charged tracks that end at vertices, which are inside the detector volume but displaced with respect to the original collision point, from which an electron or a muon is emitted. In order to probe this class of models we propose a search for disappearing charged tracks in association with displaced electrons or muons.
Bacteria Penetrate the Inner Mucus Layer before Inflammation in the Dextran Sulfate Colitis Model
Malin E. V. Johansson,Jenny K. Gustafsson,Karolina E. Sj?berg,Joel Petersson,Lena Holm,Henrik Sj?vall,Gunnar C. Hansson
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0012238
Abstract: Protection of the large intestine with its enormous amount of commensal bacteria is a challenge that became easier to understand when we recently could describe that colon has an inner attached mucus layer devoid of bacteria (Johansson et al. (2008) Proc. Natl. Acad. Sci. USA 105, 15064–15069). The bacteria are thus kept at a distance from the epithelial cells and lack of this layer, as in Muc2-null mice, allow bacteria to contact the epithelium. This causes colitis and later on colon cancer, similar to the human disease Ulcerative Colitis, a disease that still lacks a pathogenetic explanation. Dextran Sulfate (DSS) in the drinking water is the most widely used animal model for experimental colitis. In this model, the inflammation is observed after 3–5 days, but early events explaining why DSS causes this has not been described.
Common Social Work Education Standards in the Nordic Countries - opening an issue
Petersson, Sigrun Juliusdottir and Jan
Social Work and Society , 2003,
Abstract: The article analyses the option of common Nordic Standards for social work education in these countries. The option is viewed through the lens of trends in education in the different countries. In the article the notion of an Integrated Field Model is used to indicate the starting point for a common model of education. This model covers the field characteristics of Denmark and Norway and their current move towards a more research-based education. It also covers the research characteristics of education in Finland, Iceland and Sweden and their current move towards a new field connection based on research-oriented education. Some thoughts on international requirements on comparability and compatibility in this setting are addressed in the final section.
Simulated production losses in reindeer herds caused by accidental death of animals
C. J. Petersson,?. Danell
Rangifer , 1992,
Abstract: A dynamic age-structured model was used to simulate the consequences on herd production if an extra animal from a particular age class and season was lost. Herd size was adjusted to 1000 animals and a sex ratio of .75/.25 via slaughter in late autumn. Three harvest strategies were applied, ranging from extreme calf to adult harvest. Equilibrium herd structure was disturbed with the loss of an extra animal and the consequences in terms of the number of animals slaughtered and kilogram of carcasses produced were followed over a simulation period of 15 years. The loss of a male corresponded largely to 0.70 to 0.90 times its own carcass weight. Loss of a female decreased herd production by 1.2 to 1.7 times the carcass weight of the lost animal. The highest losses were observed for 4-6 year old females. Loss of a calf reduced herd production by 0.3 to 1.6 times the calf's carcass weight, depending on season of loss and harvest strategy. In general, a loss during winter decreased herd production 10 to 20 percent more than a loss during autumn.
Intracerebral metaplastic meningioma with prominent ossification and extensive calcification
Jingxiang Huang,Fredrik Petersson
Rare Tumors , 2011, DOI: 10.4081/rt.2011.e20
Abstract: We present a patient (male 26 years) with a short history of recurrent seizures induced by a largely intracerebrally located frontal lobe meningioma. The tumor displayed a heretofore unpublished combination of extensive metaplastic bone formation and prominent non-psammomatous calcifications with focal chicken-wire pattern.
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