30 research outputs found
The Intensity of Satellite Reflections in Electron Diffraction Patterns from Evaporated Alloy Films with CuAu II Type Superstructure
In order to elucidate the origin of satellite reflections flanking the direct spot in the electron diffraction pattern of a single crystal evaporated film with CuAu II type superlattice, the peak as well as integrated intensities have been measured as functions of the wavelength of electrons corresponding to the accelerating voltage from 75 to 280KV. It has been revealed that the intensity of the satellite in question relative to a fundamental reflection consists of two parts, a major part which depends on the wavelength in such a way as predicted by the theory of multiple reflection, and the other minor part which is independent of the wavelength. The existence of the latter part shows that the reflection is not a forbidden one and, therefore, a lattice modulation accompanies the regular anti-phase structure. Fourier potential due to this lattice modulation, V_s, is estimated to be in the order of one tenth the magnitude of V_ Some consideration concerning the nature of the modulation is given by comparing the results of electron and X-ray diffraction studies
Protective effect of FK506 and Thromboxane synthase inhibitor on ischemia-reperfusion injury in non-heart-beating donor in rat orthotopic liver transplantation
The study investigated the possibility of pharmacologically modulating hepatic allograft function from non-heart-beating donors (NHBDs)using male Lewisrats. The donors were divided into 4 groups :Group 1 in which the vehicle was administered, Group 2 in which FK506 (tacrolimus a powerful immunosuppressive agent)was administered,Group3 in which OKY046 (a specific thromboxane synthetase inhibitor) was administered and Group 4 in which FK506 and OKY046 were administered. The recipients received orthotopic liver transplantation. The survival rates differed significantly between the recipients that had received liver transplantation from Groups1 and 4. The serum liver enzyme and inflammatory cytokine concentrations of the recipients which had received liver transplantation from Groups 2, 3 and 4 were significantly lower than those of the recipients that had received liver transplantation from Group1. Although there was no significant difference, all parameters were better in the recipients that had received transplantation from Group 4 than those that had received transplantation from Groups 2 and 3. The action mechanisms of FK506 and OKY046 are completely different. Therefore, concomitant use of FK506 and OKY046 might have additive effects on liver transplantation from NHBDs. In conclusion, we demonstrated that pretreatment of NHBDs using FK506 and OKY 046 ameliorated graft viability
Tonic B cell activation by Radioprotective105/MD-1 promotes disease progression in MRL/lpr mice
Toll-like receptors (TLRs) have a crucial role in sensing microbial products and triggering immune responses. Recent reports have indicated that TLR7 and TLR9 have an important role in activating autoreactive B cells. In addition to TLR7 and TLR9, mouse B cells express TLR2, TLR4 and structurally related Radioprotective105 (RP105). We have previously shown that RP105 works in concert with TLR2/4 in antibody response to TLR2/4 ligands. We here report that B cells are constitutively activated by TLR2/4 and RP105. Such B cell activation was revealed by the γ3 germ line transcript and serum IgG3 production, both of which were impaired by the lack of RP105 or TLR2/4. Serum IgG3 was not altered in germ-free or antibiotics-treated mice, suggesting that the microbial flora hardly contributes to the continuous activation of B cells. The lack of RP105-dependent B cell activation ameliorated disease progression in lupus-prone MRL/lpr mice. RP105−/− MRL/lpr mice showed less lymphoadenopathy/splenomegaly and longer survival than MRL/lpr mice. Whereas glomerulonephritis and auto-antibody production were not altered, improvement in blood urea nitrogen and lower incidence of renal arteritis indicated that renal function was ameliorated in the absence of RP105. Our results suggest that RP105-dependent tonic B cell activation has a pathogenic role in MRL/lpr mic
Unc93B1 Restricts Systemic Lethal Inflammation by Orchestrating Toll-like Receptor 7 and 9 Trafficking
SummaryToll-like receptor-7 (TLR7) and 9, innate immune sensors for microbial RNA or DNA, have been implicated in autoimmunity. Upon activation, TLR7 and 9 are transported from the endoplasmic reticulum (ER) to endolysosomes for nucleic acid sensing by an ER-resident protein, Unc93B1. Little is known, however, about a role for sensor transportation in controlling autoimmunity. TLR9 competes with TLR7 for Unc93B1-dependent trafficking and predominates over TLR7. TLR9 skewing is actively maintained by Unc93B1 and reversed to TLR7 if Unc93B1 loses preferential binding via a D34A mutation. We here demonstrate that mice harboring a D34A mutation showed TLR7-dependent, systemic lethal inflammation. CD4+ T cells showed marked differentiation toward T helper 1 (Th1) or Th17 cell subsets. B cell depletion abolished T cell differentiation and systemic inflammation. Thus, Unc93B1 controls homeostatic TLR7 activation by balancing TLR9 to TLR7 trafficking
Double-Stranded RNA of Intestinal Commensal but Not Pathogenic Bacteria Triggers Production of Protective Interferon-β
SummaryThe small intestine harbors a substantial number of commensal bacteria and is sporadically invaded by pathogens, but the response to these microorganisms is fundamentally different. We identified a discriminatory sensor by using Toll-like receptor 3 (TLR3). Double-stranded RNA (dsRNA) of one major commensal species, lactic acid bacteria (LAB), triggered interferon-β (IFN-β) production, which protected mice from experimental colitis. The LAB-induced IFN-β response was diminished by dsRNA digestion and treatment with endosomal inhibitors. Pathogenic bacteria contained less dsRNA and induced much less IFN-β than LAB, and dsRNA was not involved in pathogen-induced IFN-β induction. These results identify TLR3 as a sensor to small intestinal commensal bacteria and suggest that dsRNA in commensal bacteria contributes to anti-inflammatory and protective immune responses