Complete resection of the gastric antrum decreased incidence and severity of delayed gastric emptying after pancreaticoduodenectomy

Background:Delayed gastric emptying(DGE)is the main complication after pancreaticoduodenectomy(PD),but the mechanism is still unclear.The aim of this study was to elucidate the role of complete resection of the gastric antrum in decreasing incidence and severity of DGE after PD.Methods:Sprague-Dawley rats were divided into three groups:expanded resection(ER group),complete resection(CR group),and incomplete resection(IR group)of the gastric antrum.The tension(g)of remnant stomach contraction was observed.We analyzed the histological morphology of the gastric wall by different excisional methods after distal gastrectomy.Moreover,patients underwent PD at our department between January 2012 and May 2016 were included in the study.These cases were divided into IR group and CR group of the gastric antrum,and the clinical data were retrospectively analyzed.Results:The ex vivo remnant stomachs of CR group exhibited much greater contraction tension than others(P<0.05).The contraction tension of the remnant stomach increased with increasing acetylcholine concentration,while remained stable at the concentration of 10×10^(-5 )mol/L.Furthermore,174 consecutive patients were included and retrospectively analyzed in the study.The incidence of DGE was significantly lower(3.5%vs.21.3%,P<0.01)in CR group than in IR group.In addition,hematoxylin-eosin staining analyses of the gastric wall confirmed that the number of transected circular smooth muscle bundles were higher in IR group than in CR group(8.24±0.65 vs.3.76±0.70,P<0.05).Conclusions:The complete resection of the gastric antrum is associated with decreased incidence and severity of DGE after PD.Gastric electrophysiological and physiopathological disorders caused by damage to gastric smooth muscles might be the mechanism underlying DGE.

Effect of thermal annealing on the microstructure, mechanical properties and residual stress relaxation of pure titanium after deep rolling treatment

The aim of this paper was to investigate the effect of thermal annealing on the microstructure, mechanical properties, and residual stress relaxation of deep rolled pure titanium. The microstructure and mechanical properties of the surface modified layer were analyzed by metallographic microscopy, transmission electron microscope and in-situ tensile testing. The results showed that the annealed near-surface layer with fine recrystallized grains had increased ductility but decreased strength after annealing below the recrystallization temperature, where the tensile strength was still higher than that of the substrate. After annealing at the recrystallization temperature, the recrystallized near-surface layer had smaller grain size,similar tensile strength, and higher proportional limit, comparable to those of the substrate. Moreover, the residual stress relaxation showed evidently different mechanisms at three different temperature regions:low temperature(T≤ 0.2 Tm), medium temperature(T≈(0.2–0.3) Tm), and high temperature(T≥ 0.3 Tm).Furthermore, a prediction model was proposed in terms of modification of Zener-Wert-Avrami model,which showed promise in characterizing the residual stress relaxation in commercial pure Ti during deep rolling at elevated temperature.

Fisl phosphorylation by Met promotes mitochondrial fission and hepatocellular carcinoma metastasis

Met tyrosine kinase,a receptor for a hepatocyte growth factor(HGF),plays a critical role in tumor growth,metastasis,and drug resistance.Mitochondria are highly dynamic and undergo fission and fusion to maintain a functional mitochondrial network.Dysregulated mitochondrial dynamics are responsible for the progression and metastasis of many cancers.Here,using structured illumination microscopy(SIM)and high spatial and temporal resolution live cell imaging,we identified mitochondrial trafficking of receptor tyrosine kinase Met.The ton tacts betwee n activated Met kinase and mitochondria formed dramatically,and an intact HGF/Met axis was necessary for dysregulated mitochondrial fission and cancer cell movements.Mechanically,we found that Met directly phosphorylated outer mitochondrial membrane protein Fis1 at Tyr38(Fisl pY38).Fisl pY38 promoted mitochondrial fission by recruiting the mitochondrial fission GTPase dynamin-related protein・1(Drp1)to mitochondria.Fragmented mitochondria fueled actin filament remodeling and lamellipodia or invadopodia formation to facilitate cell metastasis in hepatocellular carcinoma(HCC)cells both in vitro and in vivo.These findings reveal a novel and noncanonical pathway of Met receptor tyrosine kinase in the regulation of mitochondrial activities,which may provide a therapeutic target for metastatic HCC.