AIM:To evaluate the effects of diazoxide on ischemia/reperfusion(I/R)-injured hepatocytes and further elucidate its underlying mechanisms.METHODS:Male Sprague-Dawley rats were randomized(8 for donor and recipient per ...AIM:To evaluate the effects of diazoxide on ischemia/reperfusion(I/R)-injured hepatocytes and further elucidate its underlying mechanisms.METHODS:Male Sprague-Dawley rats were randomized(8 for donor and recipient per group)into five groups:I/R group(4 h of liver cold ischemia followed by 6 h of reperfusion);heme oxygenase-1(HO-1)small interfering RNA(siRNA)group(injection of siRNA via donor portal vein 48 h prior to harvest);diazoxide(DZ) group(injection of DZ via donor portal vein 10 min prior to harvest);HO-1 siRNA+DZ group;and siRNA control group.Blood and liver samples were collected at 6 h after reperfusion.The mRNA expressions and protein levels of HO-1 were determined by reverse transcription polymerase chain reaction and Western blotting,and tissue morphology was examined by light and transmission electron microscopy.Serum transaminases level and cytokines concentration were also measured.RESULTS:We observed that a significant reduction of HO-1 mRNA and protein levels in HO-1 siRNA and HO-1 siRNA+DZ group when compared with I/R group,while the increases were prominent in the DZ group.Light and transmission electron microscopy indicated severe disruption of tissue with lobular distortion and mitochondrial cristae damage in the HO-1 siRNA and HO-1 siRNA+DZ groups compared with DZ group.Serum alanine aminotransferase,aspartate transaminase,tumor necrosis factor-αand interleukin-6 levels increased in the HO-1 siRNA and HO-1 siRNA+DZ groups,and decreased in the DZ group.CONCLUSION:The protective effect of DZ may be induced by upregulation of HO-1.By inhibiting expression of HO-1,this protection pretreated with DZ was abolished.展开更多
The health effects of ambient PM 2.5 and its potential mechanisms have generated considerable interest.In vitro cell studies and ex vivo animal experiments may not accurately determine the characteristics of PM 2.5 pa...The health effects of ambient PM 2.5 and its potential mechanisms have generated considerable interest.In vitro cell studies and ex vivo animal experiments may not accurately determine the characteristics of PM 2.5 particles.To better understand their detailed mechanisms,we performed an in vivo study using single photon emission tomography(SPECT)imaging.To mimic the PM 2.5 particles,SiO2 nanoparticles modified by ethylene carbonate or polyvinyl pyrrolidone were labeled with 131I.After administration via inhalation,in vivo SPECT imaging of the radiolabeled particles in sprague dawley rats was performed.It was found that radioactivity accumulated in the lungs and trachea 6 and 24 h after administration.In addition,significant radioactivity was observed in the abdomen,including the liver and kidneys.The results were also confirmed by ex vivo autoradiography.This study revealed that in vivo SPECT imaging could be an effective method for investigating the properties of PM 2.5 particles.展开更多
Polyl(lactide),PLA,suffers from bitleness and low heat deflection temperature(HDT),which limits its application as an engineering plastic.In this work,poly(L-lactide)/poly(D-lactide)/ethylene-vinyl acetate glycidyl me...Polyl(lactide),PLA,suffers from bitleness and low heat deflection temperature(HDT),which limits its application as an engineering plastic.In this work,poly(L-lactide)/poly(D-lactide)/ethylene-vinyl acetate glycidyl methacrylate random copolymer(PLLA/PDL A/EVM-GMA=1/1/x)composites were prepared by melt blending,and the in situ formed EVM-g PLA copolymers improved the compatibility between PLA and EVM-GMA.Subsequently,the blends were subjected to a two-step annealing process during compression molding,i.e.first annealing at 120℃ to rapidly form a certain amount of stereocomplex(sc)crystallites as nucleation sites,and then annealing at 200℃ to guide the formation of new sccrystallites.Both differential scanning calorimetry(DSC)and wide angle X-ray dffrction(WAXD)measurements confirmed the formation of highly stereocomplexed PLA products.Mechanical results showed that the PLLA/PDLA blend with 20 wt%of EVM-GMA had a notched impact strength up to 65 kJ/m2 and an elongation at break of 48%,while maintaining a tensile strength of 40 MPa.Meanwhile,dynamic mechanical analysis(DMA)and heat deflection tests showed that the PLA composite had an HDT up to 142℃ which is 90℃ higher than that of normal PLA products.Scanning electron microscopy(SEM)confirmed the fine dispersion of EVM-GMA particles,which facilitated to understand the toughening mechanism.Furthermore,the highly stereocomplexed PLA composites simultaneously exhibited excellent chemical and hydrolysis resistance.Therefore,these fascinating properties may extend the application range of sc PLA material as an engineering bioplastic.展开更多
In this work, hydroxyl-terminated oxalamide compounds N^(1),N^(2)-bis(2-hydroxyethyl)oxalamide(OXA1) and N^(1),N^(1)′-(ethane-1,2-diyl)bis(N^(2)-(2-hydroxyethyl)oxalamide(OXA2) were synthesized to initiate the ring-o...In this work, hydroxyl-terminated oxalamide compounds N^(1),N^(2)-bis(2-hydroxyethyl)oxalamide(OXA1) and N^(1),N^(1)′-(ethane-1,2-diyl)bis(N^(2)-(2-hydroxyethyl)oxalamide(OXA2) were synthesized to initiate the ring-opening polymerization of L-lactide for preparation of oxalamide-hybridized poly(L-lactide)(PLA_(OXA)), i.e., PLA_(OXA1) and PLA_(OXA2). The crystallization properties of PLA were improved by the self-assembly of the oxalamide segments in PLA_(OXA) which served as the initial heterogeneous nuclei. The crystal growth kinetics was studied by HoffmanLauritzen theory and it revealed that the nucleation energy barrier of PLA_(OXA1) and PLA_(OXA2) was lower than that of PLA. Consequently, PLA_(OXA) could crystallize much faster than PLA, accompanied with a decrease in spherulite size and half-life crystallization time by 74.8% and 86.5%(T=125 ℃), respectively. In addition, the final crystallinity of PLA_(OXA1) and PLA_(OXA2) was 6 and 8 times higher, respectively, in comparison with that of neat PLA under a controlled cooling rate of 10 ℃/min. The results demonstrate that the hybridization of oxalamide segments in PLA backbone will serve as the self-heteronucleation for promoting the crystallization rate. The higher the content of oxalamide segments(PLA_(OXA2) compared with PLA_(OXA1)) is, the stronger the promotion effect will be. Therefore, this study may provide a universal approach by hybridizing macromolecular structure to facilitate the crystallization of semi-crystalline polymer materials.展开更多
基金Supported by Social Development Projects of Yunnan Province,No.2008CA026
文摘AIM:To evaluate the effects of diazoxide on ischemia/reperfusion(I/R)-injured hepatocytes and further elucidate its underlying mechanisms.METHODS:Male Sprague-Dawley rats were randomized(8 for donor and recipient per group)into five groups:I/R group(4 h of liver cold ischemia followed by 6 h of reperfusion);heme oxygenase-1(HO-1)small interfering RNA(siRNA)group(injection of siRNA via donor portal vein 48 h prior to harvest);diazoxide(DZ) group(injection of DZ via donor portal vein 10 min prior to harvest);HO-1 siRNA+DZ group;and siRNA control group.Blood and liver samples were collected at 6 h after reperfusion.The mRNA expressions and protein levels of HO-1 were determined by reverse transcription polymerase chain reaction and Western blotting,and tissue morphology was examined by light and transmission electron microscopy.Serum transaminases level and cytokines concentration were also measured.RESULTS:We observed that a significant reduction of HO-1 mRNA and protein levels in HO-1 siRNA and HO-1 siRNA+DZ group when compared with I/R group,while the increases were prominent in the DZ group.Light and transmission electron microscopy indicated severe disruption of tissue with lobular distortion and mitochondrial cristae damage in the HO-1 siRNA and HO-1 siRNA+DZ groups compared with DZ group.Serum alanine aminotransferase,aspartate transaminase,tumor necrosis factor-αand interleukin-6 levels increased in the HO-1 siRNA and HO-1 siRNA+DZ groups,and decreased in the DZ group.CONCLUSION:The protective effect of DZ may be induced by upregulation of HO-1.By inhibiting expression of HO-1,this protection pretreated with DZ was abolished.
基金supported by the National Natural Science Foundation of China(Nos.31671035,51803082)National Significant New Drugs Creation Program(No.2017ZX09304021)+1 种基金Jiangsu Province Foundation(Nos.BK20170204,BK20161137)Jiangsu Provincial Medical Innovation Team(Nos.CXTDA2017024,LGY2017088,QNRC2016628)。
文摘The health effects of ambient PM 2.5 and its potential mechanisms have generated considerable interest.In vitro cell studies and ex vivo animal experiments may not accurately determine the characteristics of PM 2.5 particles.To better understand their detailed mechanisms,we performed an in vivo study using single photon emission tomography(SPECT)imaging.To mimic the PM 2.5 particles,SiO2 nanoparticles modified by ethylene carbonate or polyvinyl pyrrolidone were labeled with 131I.After administration via inhalation,in vivo SPECT imaging of the radiolabeled particles in sprague dawley rats was performed.It was found that radioactivity accumulated in the lungs and trachea 6 and 24 h after administration.In addition,significant radioactivity was observed in the abdomen,including the liver and kidneys.The results were also confirmed by ex vivo autoradiography.This study revealed that in vivo SPECT imaging could be an effective method for investigating the properties of PM 2.5 particles.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51873082 and 51903106)Fundamental Research Funds for the Central Universities(No.JUSRP11928).
文摘Polyl(lactide),PLA,suffers from bitleness and low heat deflection temperature(HDT),which limits its application as an engineering plastic.In this work,poly(L-lactide)/poly(D-lactide)/ethylene-vinyl acetate glycidyl methacrylate random copolymer(PLLA/PDL A/EVM-GMA=1/1/x)composites were prepared by melt blending,and the in situ formed EVM-g PLA copolymers improved the compatibility between PLA and EVM-GMA.Subsequently,the blends were subjected to a two-step annealing process during compression molding,i.e.first annealing at 120℃ to rapidly form a certain amount of stereocomplex(sc)crystallites as nucleation sites,and then annealing at 200℃ to guide the formation of new sccrystallites.Both differential scanning calorimetry(DSC)and wide angle X-ray dffrction(WAXD)measurements confirmed the formation of highly stereocomplexed PLA products.Mechanical results showed that the PLLA/PDLA blend with 20 wt%of EVM-GMA had a notched impact strength up to 65 kJ/m2 and an elongation at break of 48%,while maintaining a tensile strength of 40 MPa.Meanwhile,dynamic mechanical analysis(DMA)and heat deflection tests showed that the PLA composite had an HDT up to 142℃ which is 90℃ higher than that of normal PLA products.Scanning electron microscopy(SEM)confirmed the fine dispersion of EVM-GMA particles,which facilitated to understand the toughening mechanism.Furthermore,the highly stereocomplexed PLA composites simultaneously exhibited excellent chemical and hydrolysis resistance.Therefore,these fascinating properties may extend the application range of sc PLA material as an engineering bioplastic.
基金financially supported by the National Natural Science Foundation of China(No.51873082)the MOE&SAFEA 111 Project(No.B13025)+1 种基金the Opening Project of Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics(Beijing Technology and Business University)(No.QETHSP2019003)the Postgraduate Research&Practice Innovation Program of Jiangnan University(No.JNKY19020)。
文摘In this work, hydroxyl-terminated oxalamide compounds N^(1),N^(2)-bis(2-hydroxyethyl)oxalamide(OXA1) and N^(1),N^(1)′-(ethane-1,2-diyl)bis(N^(2)-(2-hydroxyethyl)oxalamide(OXA2) were synthesized to initiate the ring-opening polymerization of L-lactide for preparation of oxalamide-hybridized poly(L-lactide)(PLA_(OXA)), i.e., PLA_(OXA1) and PLA_(OXA2). The crystallization properties of PLA were improved by the self-assembly of the oxalamide segments in PLA_(OXA) which served as the initial heterogeneous nuclei. The crystal growth kinetics was studied by HoffmanLauritzen theory and it revealed that the nucleation energy barrier of PLA_(OXA1) and PLA_(OXA2) was lower than that of PLA. Consequently, PLA_(OXA) could crystallize much faster than PLA, accompanied with a decrease in spherulite size and half-life crystallization time by 74.8% and 86.5%(T=125 ℃), respectively. In addition, the final crystallinity of PLA_(OXA1) and PLA_(OXA2) was 6 and 8 times higher, respectively, in comparison with that of neat PLA under a controlled cooling rate of 10 ℃/min. The results demonstrate that the hybridization of oxalamide segments in PLA backbone will serve as the self-heteronucleation for promoting the crystallization rate. The higher the content of oxalamide segments(PLA_(OXA2) compared with PLA_(OXA1)) is, the stronger the promotion effect will be. Therefore, this study may provide a universal approach by hybridizing macromolecular structure to facilitate the crystallization of semi-crystalline polymer materials.
