Objective To investigate the effects of urotensin Ⅱ/urotensin Ⅱreceptor ( UⅡ/UT) system on the expression of inflammatory signal molecules p 38 mitogen-activated protein kinase ( p38 MAPK) and nuclear factor-κB ( NF-κB ) in lipopolysaccharide ( LPS )-stimulated Kupffer cells ( KCs ) . Methods Rat KCs were isolated and purified by means of in situ perfusion and density gradient centrifuga-tion.The isolated cells were randomly divided into six treatment groups including group 1:UⅡ(-) urantide (-)LPS(-), group 2:UⅡ(+)urantide(-)LPS(-), group 3: UⅡ(-)urantide(+)LPS(-), group 4:UⅡ(-)urantide(-)LPS(+), group 5:UⅡ(+) urantide(-) LPS(+) and group 6:UⅡ(-)urantide(+) LPS(+) .Western blot assay was performed to detect p 38 MAPK/p-p38 MAPK protein and NF-κB p65 sub-unit.The DNA-binding activity of NF-κB was tested by electrophoretic mobility shift assay (EMSA).Re-sults There was no significant difference with the expression of p 38 MAPK protein in KCs among the six groups (P>0.05).The expression of p65 protein and p-p38 MAPK and the DNA-binding activity of NF-κB were significantly enhanced in LPS-stimulated KCs from groups 4, 5 and 6 in comparison with those in group 1 (P<0.01).No significant differences with the levels of p65 protein and phosphor-p38 MAPK and the DNA-binding activity of NF-κB were observed between UⅡ/urantide-treated cells ( group 2 or group 3) and untreated cells (group 1) (all P>0.05), but that were decreased in group 6 than those in group 4 (all P<0.01).Conclusion UⅡ/UT system participated in the activation of p38 MAPK and NF-κB signaling pathways in LPS-stimulated primary Kupffer cells .

In cardiac ablation procedures,the accuracy of catheter positioning determines the authenticity of the cardiac model and the accuracy of the ablation target.This article reviews the literature on catheter positioning in electrophysiology and summarizes the key technologies for catheter positioning,such as magnetic-electric fusion and interference suppression.Addressing the limitations of electric and magnetic positioning individually,the paper elaborates on the rationale for catheter positioning technology based on magnetic-electric fusion.It also outlines the framework of a complex catheter positioning system.Specifically,the magnetoelectric conversion matrix is established first,followed by the optimization of the catheter shape.The interference factors such as magnetic field interference,body movement,respiration,and heartbeat in catheter positioning and their suppression methods are analyzed and discussed in detail.Finally,the development trend of three-dimensional electrophysiology catheter positioning technology is prospected,offering feasible insights for the research on catheter positioning technology based on magnetic-electric fusion.