Temperature- and Size-dependence of Line shape of ESR spectra of XXZ antiferromagnetic chain

The ESR (Electron Spin Resonance) spectrum of the XXZ spin chain with finite length shows a double-peak structure at high temperatures around the EPR (Electron Paramagnetic Resonance) resonance frequency. This fact has been pointed out by direct numerical methods (S. El Shawish, O. Cepas and S. Miyashita; H. Ikeuchi, H. De Raedt, S. Bertaina and S. Miyashita). On the other hand, at low temperatures the spectrum has a single peak with a finite shift from the frequency of EPR as predicted by the analysis of field theoretical works (M. Oshikawa and I. Affleck). We study how the spectrum changes with the temperature, and also we study the size-dependence of the line shape including the even-odd effect. In order to understand those dependences, we introduce a decomposition of the spectrum into contributions from transitions specified by magnetization, and we characterize the structure of the spectrum by individual contributions. Applying the moment method introduced by M. Brockman et al., to each component, we analyze the size-dependence of the structure of the spectrum, which supports the numerical observation that separation of the double-peak structure vanishes inversely with the size.Comment: 11 pages, 10 figure

SR-PSOX/CXCL16 plays a critical role in the progression of colonic inflammation.

Inflammatory bowel disease (IBD) is initiated and perpetuated by a dysregulated immune response to unknown environmental antigens such as luminal bacteria in genetically susceptible hosts. SR-PSOX/CXCL16, a scavenger receptor that binds phosphatidylserine and oxidised lipoprotein, has both phagocytic activity and chemotactic properties. The aim of this study was to investigate the role of SR-PSOX/CXCL16 in patients with IBD and experimental murine colitis

Activation of focal adhesion kinase via M1 muscarinic acetylcholine receptor is required in restitution of intestinal barrier function after epithelial injury

AbstractImpairment of epithelial barrier is observed in various intestinal disorders including inflammatory bowel diseases (IBD). Numerous factors may cause temporary damage of the intestinal epithelium. A complex network of highly divergent factors regulates healing of the epithelium to prevent inflammatory response. However, the exact repair mechanisms involved in maintaining homeostatic intestinal barrier integrity remain to be clarified.In this study, we demonstrate that activation of M1 muscarinic acetylcholine receptor (mAChR) augments the restitution of epithelial barrier function in T84 cell monolayers after ethanol-induced epithelial injury, via ERK-dependent phosphorylation of focal adhesion kinase (FAK). We have shown that ethanol injury decreased the transepithelial electrical resistance (TER) along with the reduction of ERK and FAK phosphorylation. Carbachol (CCh) increased ERK and FAK phosphorylation with enhanced TER recovery, which was completely blocked by either MT-7 (M1 antagonist) or atropine. The CCh-induced enhancement of TER recovery was also blocked by either U0126 (ERK pathway inhibitor) or PF-228 (FAK inhibitor). Treatment of T84 cell monolayers with interferon-γ (IFN-γ) impaired the barrier function with the reduction of FAK phosphorylation. The CCh-induced ERK and FAK phosphorylation were also attenuated by the IFN-γ treatment. Immunological and binding experiments exhibited a significant reduction of M1 mAChR after IFN-γ treatment. The reduction of M1 mAChR in inflammatory area was also observed in surgical specimens from IBD patients, using immunohistochemical analysis. These findings provide important clues regarding mechanisms by which M1 mAChR participates in the maintenance of intestinal barrier function under not only physiological but also pathological conditions

Inducible colitis-associated glycome capable of stimulating the proliferation of memory CD4+ T cells

Immune responses are modified by a diverse and abundant repertoire of carbohydrate structures on the cell surface, which is known as the glycome. In this study, we propose that a unique glycome that can be identified through the binding of galectin-4 is created on local, but not systemic, memory CD4+ T cells under diverse intestinal inflammatory conditions, but not in the healthy state. The colitis-associated glycome (CAG) represents an immature core 1–expressing O-glycan. Development of CAG may be mediated by down-regulation of the expression of core-2 β1,6-N-acetylglucosaminyltransferase (C2GnT) 1, a key enzyme responsible for the production of core-2 O-glycan branch through addition of N-acetylglucosamine (GlcNAc) to a core-1 O-glycan structure. Mechanistically, the CAG seems to contribute to super raft formation associated with the immunological synapse on colonic memory CD4+ T cells and to the consequent stabilization of protein kinase C θ activation, resulting in the stimulation of memory CD4+ T cell expansion in the inflamed intestine. Functionally, CAG-mediated CD4+ T cell expansion contributes to the exacerbation of T cell–mediated experimental intestinal inflammations. Therefore, the CAG may be an attractive therapeutic target to specifically suppress the expansion of effector memory CD4+ T cells in intestinal inflammation such as that seen in inflammatory bowel disease