BACKGROUND Crohn’s disease(CD)is a chronic inflammatory bowel disease with unknown etiology.Inflammatory chemical mediators synthesized from arachidonic acid,an n-6 polyunsaturated fatty acid(PUFA),have been shown to...BACKGROUND Crohn’s disease(CD)is a chronic inflammatory bowel disease with unknown etiology.Inflammatory chemical mediators synthesized from arachidonic acid,an n-6 polyunsaturated fatty acid(PUFA),have been shown to activate CD.Additionally,n-3 PUFAs are metabolized by the same enzyme as n-6 PUFAs and known to inhibit the arachidonic acid cascade.Our previous study noted that the presence of erythrocyte membrane fatty acids is a characteristic finding in Japanese CD patients.It was thus speculated that FADS2 gene polymorphisms,which induce PUFA metabolizing enzymes,are involved in the pathogenesis of CD,though no such relationship was found.AIM To investigate the relationship of FADS2 polymorphisms with serum and erythrocyte membrane fatty acid composition ratios,and disease activity.METHODS Using previously reported findings regarding FADS2 genetic polymorphisms,the records of 52 CD patients undergoing treatment at Jikei University Kashiwa Hospital were analyzed.Mutations noted were divided into three groups;wild-type(GG),heterozygous mutants(GA),and homozygous(AA),with the activities of delta-6 and delta-5 desaturases compared using redefined d6d index(rd.d6di)and d5d index(d5di).Additionally,comparisons of serum and erythrocyte membranes for fatty acid composition,and also gene polymorphisms and CD activity index(CDAI)were performed.RESULTS The presence of the rs174538 mutation in FADS2 resulted in reduction of only rd.d6di in the erythrocyte membrane(P<0.01).In contrast,that mutation was found to be associated with d5di induced by FADS1 in serum(P=0.019)as well as the erythrocyte membrane(P<0.0001),and also with reduction in the fatty acid composition of arachidonic acid in both serum(P<0.0001)and the erythrocyte membrane(P<0.01).Regarding disease activity,a positive correlation of CDAI score with rd.d6di in both serum(P<0.05)and the erythrocyte membrane(P<0.05)was found only in the rs174538 wild-type group.In contrast,there was no correction between CDAI and d5di in either serum or erythrocyte membrane samples.CONCLUSION The rs174538 mutation alters the fatty acid profile through strong linkage to the FADS1 gene.In wild-type individuals,rd.d6di was positively correlated with CDAI,suggesting predictive utility of disease severity.展开更多
文摘BACKGROUND Crohn’s disease(CD)is a chronic inflammatory bowel disease with unknown etiology.Inflammatory chemical mediators synthesized from arachidonic acid,an n-6 polyunsaturated fatty acid(PUFA),have been shown to activate CD.Additionally,n-3 PUFAs are metabolized by the same enzyme as n-6 PUFAs and known to inhibit the arachidonic acid cascade.Our previous study noted that the presence of erythrocyte membrane fatty acids is a characteristic finding in Japanese CD patients.It was thus speculated that FADS2 gene polymorphisms,which induce PUFA metabolizing enzymes,are involved in the pathogenesis of CD,though no such relationship was found.AIM To investigate the relationship of FADS2 polymorphisms with serum and erythrocyte membrane fatty acid composition ratios,and disease activity.METHODS Using previously reported findings regarding FADS2 genetic polymorphisms,the records of 52 CD patients undergoing treatment at Jikei University Kashiwa Hospital were analyzed.Mutations noted were divided into three groups;wild-type(GG),heterozygous mutants(GA),and homozygous(AA),with the activities of delta-6 and delta-5 desaturases compared using redefined d6d index(rd.d6di)and d5d index(d5di).Additionally,comparisons of serum and erythrocyte membranes for fatty acid composition,and also gene polymorphisms and CD activity index(CDAI)were performed.RESULTS The presence of the rs174538 mutation in FADS2 resulted in reduction of only rd.d6di in the erythrocyte membrane(P<0.01).In contrast,that mutation was found to be associated with d5di induced by FADS1 in serum(P=0.019)as well as the erythrocyte membrane(P<0.0001),and also with reduction in the fatty acid composition of arachidonic acid in both serum(P<0.0001)and the erythrocyte membrane(P<0.01).Regarding disease activity,a positive correlation of CDAI score with rd.d6di in both serum(P<0.05)and the erythrocyte membrane(P<0.05)was found only in the rs174538 wild-type group.In contrast,there was no correction between CDAI and d5di in either serum or erythrocyte membrane samples.CONCLUSION The rs174538 mutation alters the fatty acid profile through strong linkage to the FADS1 gene.In wild-type individuals,rd.d6di was positively correlated with CDAI,suggesting predictive utility of disease severity.
文摘OP2S发动机(Opposed-Piston Two-Stroke,OP2S,对置活塞二冲程发动机)相较于传统四冲程发动机,具有功率密度高、热负荷高的特点,需在活塞内部设计内冷油腔对其进行强制振荡冷却,以确保活塞在严苛环境下安全可靠地工作。以某OP2S发动机活塞内冷油腔为设计对象,应用三维建模软件和流体传热计算软件Fluent,建立了卵形、椭圆形和水滴形三种截面形状的油腔模型作为研究对象,采用VOF(volume of fluid)多相流模型、动网格技术等,对活塞内冷油腔强制振荡冷却过程进行了流动和换热分析。经过分析得知,活塞内冷油腔的截面形状、喷油速度等影响因素对其振荡冷却的流动和换热特性影响较大。在2800 r/min额定转速下,卵形油腔的壁面平均换热系数分别高于水滴形和椭圆形油腔7%和4%。通过对不同喷油速度条件下的内冷油腔流动和换热特性分析得出了OP2S发动机活塞内冷油腔的流动和换热规律,同时确定了该发动机的冷却喷嘴机油流速,对同类型活塞内冷油腔的设计具有参考意义。
