BACKGROUND:Studies have shown that low molecular weight heparin-superoxide dismutase conjugate exhibits a remarkable neuroprotective effect. OBJECTIVE:To investigate the effect of low molecular weight heparin-superoxi...BACKGROUND:Studies have shown that low molecular weight heparin-superoxide dismutase conjugate exhibits a remarkable neuroprotective effect. OBJECTIVE:To investigate the effect of low molecular weight heparin-superoxide dismutase conjugate on astrocytes in an interleukin-6(IL-6) overexpressing mice following local cerebral ischemia. DESIGN,TIME AND SETTING:Randomized,cytological,controlled,animal study was performed in the Department of Physiology and Neuroscience,Neurology and Biochemistry and Molecular Biology,Medical University of South Carolina from January 2005 to March 2005. MATERIALS:Nine IL-6 transgenic mice,irrespective of gender,were randomly divided into three groups:sham-operated,model,and treatment,with three mice in each group.With exception of the sham-operated group,right middle cerebral artery occlusion was induced in the mice. Expression of glial fibrillary acidic protein,an astrocyte marker,was determined by immunohistochemistry.Low molecular weight heparin-superoxide dismutase conjugate was purchased from Biochemistry and Biotechnique Institute,Shandong University. METHODS:Two minutes prior to ischemia induction,0.5 mL/kg saline or 20 000 U/kg low molecular weight heparin-superoxide dismutase conjugate were administrated via the femoral artery in the model group and treatment group,respectively.The sham-operated group underwent the same protocols,with the exception of occlusion and treatment. MAIN OUTCOME MEASURES:The number of glial fibrillary acidic protein-positive cells was quantified under light microscopy(x200). RESULTS:In the sham-operated group,there were a large number of astrocytes in the IL-6 transgenic mice.However,the cell bodies were small,and the branches were few and thin.The number of astrocytes in the model group was remarkably less than the sham-operated group. Compared to the model and sham-operated groups,the number of astrocytes significantly increased,and the cell body became larger,following treatment with low molecular weight heparin-superoxide dismutase conjugate.Astrocytes exhibited hypertrophy and hyperplasia,and the processes became longer and thicker. CONCLUSION:The low molecular weight heparin-superoxide dismutase conjugate may provide neuroprotection through astrocytic activation at the super-early stage of cerebral ischemia and reperfusion.展开更多
BACKGROUND:Several studies have demonstrated that low molecular weight heparin-superoxide dismutase (LMWH-SOD) conjugate may exhibit good neuroprotective effects on cerebral ischemia/reperfusion injury though anticoag...BACKGROUND:Several studies have demonstrated that low molecular weight heparin-superoxide dismutase (LMWH-SOD) conjugate may exhibit good neuroprotective effects on cerebral ischemia/reperfusion injury though anticoagulation,decreasing blood viscosity,having anti-inflammatory activity,and scavenging oxygen free radicals. OBJECTIVE: To investigate the intervention effects of LMWH-SOD conjugate on serum levels of nitric oxide (NO),glutathione peroxidase (GSH-Px),and myeloperoxidase (MPO) following cerebral ischemia/reperfusion injury. DESIGN,TIME AND SETTING: A randomized,controlled,and neurobiochemical experiment was performed at the Institute of Biochemical Pharmacy,School of Pharmaceutical Sciences,Shandong University between April and July 2004. MATERIALS: A total of 60 Mongolian gerbils of either gender were included in this study. Total cerebral ischemia/reperfusion injury was induced in 50 gerbils by occluding bilateral common carotid arteries. The remaining 10 gerbils received a sham-operation (sham-operated group). Kits of SOD,NO,and MPO were sourced from Nanjing Jiancheng Bioengineering Institute,China. LMWH,SOD,and LMWH-SOD conjugates were provided by Institute of Biochemistry and Biotechnique,Shandong University,China. METHODS: Fifty successful gerbil models of total cerebral ischemia/reperfusion injury were evenly randomized to five groups: physiological saline,LMWH-SOD,SOD,LMWH + SOD,and LMWH. At 2 minutes prior to ischemia,0.5 mL/65 g physiological saline,20 000 U/kg LMWH-SOD conjugate,20 000 U/kg SOD,a mixture of SOD (20 000 U/kg) and LMWH (LMWH dose calculated according to weight ratio,LMWH: SOD=23.6:51),and LMWH (dose as in the LMWH + SOD group) were administered through the femoral artery in each above-mentioned group,respectively. MAIN OUTCOME MEASURES: Serum levels of NO,MPO,and GSH-Px. RESULTS: Compared with 10 sham-operated gerbils,the cerebral ischemia/reperfusion injury gerbils exhibited decreased serum levels of GSH-Px and increased serum levels of NO and MPO (P<0.01). The serum level of GSH-Px was significantly upregulated in all groups,in particular in the LMWH-SOD group (P<0.01),compared with the physiological saline group (P<0.05-0.01). Following medical treatment,serum levels of NO and MPO were significantly downregulated in all groups,in particular in the LMWH-SOD group (P<0.01). Serum levels of GSH-Px,NO,and MPO in the LMWH-SOD group were close to those in the sham-operated group (P > 0.05). CONCLUSION: In cerebral ischemia/reperfusion injury,LMWH-SOD conjugate exhibits stronger neuroprotective effects on free radical scavenging,inflammation inhibition,and cytotoxicity inhibition than simple or combined application of LMWH and SOD by downregulating NO and MPO levels and upregulating the GSH-Px level.展开更多
To date,copper-based catalysts are one of the most prominent catalysts that can electrochemically reduce CO_(2)towards highvalue fuels or chemicals,such as ethylene,ethanol,and acetic acid.However,the chemically activ...To date,copper-based catalysts are one of the most prominent catalysts that can electrochemically reduce CO_(2)towards highvalue fuels or chemicals,such as ethylene,ethanol,and acetic acid.However,the chemically active feature of Cu-based catalysts hinders the understanding of the intrinsic catalytic active sites during the initial and the operative processes of electrochemical CO_(2)reduction(CO_(2)RR).The identification and engineering of active sites during the dynamic evolution of catalysts are thereby vital to further improve the activity,selectivity,and durability of Cu-based catalysts for high-performance CO_(2)RR.In this regard,four triggers for the dynamic evolution of catalysts were introduced in detail.Afterward,three typical active-site theories during the dynamic reconstruction of catalysts were discussed.In addition,the strategies in catalyst design were summarized according to the latest reports of Cu-based catalysts for CO_(2)RR,including the tuning of electronic structure,controlling of the external potential,and regulation of local catalytic environment.Finally,the conclusions and perspectives were provided to inspire more investigations and studies on the intrinsic active sites during the dynamic evolution of catalysts,which could promote the optimization of the catalyst system to further improve the performance of CO_(2)RR.展开更多
文摘BACKGROUND:Studies have shown that low molecular weight heparin-superoxide dismutase conjugate exhibits a remarkable neuroprotective effect. OBJECTIVE:To investigate the effect of low molecular weight heparin-superoxide dismutase conjugate on astrocytes in an interleukin-6(IL-6) overexpressing mice following local cerebral ischemia. DESIGN,TIME AND SETTING:Randomized,cytological,controlled,animal study was performed in the Department of Physiology and Neuroscience,Neurology and Biochemistry and Molecular Biology,Medical University of South Carolina from January 2005 to March 2005. MATERIALS:Nine IL-6 transgenic mice,irrespective of gender,were randomly divided into three groups:sham-operated,model,and treatment,with three mice in each group.With exception of the sham-operated group,right middle cerebral artery occlusion was induced in the mice. Expression of glial fibrillary acidic protein,an astrocyte marker,was determined by immunohistochemistry.Low molecular weight heparin-superoxide dismutase conjugate was purchased from Biochemistry and Biotechnique Institute,Shandong University. METHODS:Two minutes prior to ischemia induction,0.5 mL/kg saline or 20 000 U/kg low molecular weight heparin-superoxide dismutase conjugate were administrated via the femoral artery in the model group and treatment group,respectively.The sham-operated group underwent the same protocols,with the exception of occlusion and treatment. MAIN OUTCOME MEASURES:The number of glial fibrillary acidic protein-positive cells was quantified under light microscopy(x200). RESULTS:In the sham-operated group,there were a large number of astrocytes in the IL-6 transgenic mice.However,the cell bodies were small,and the branches were few and thin.The number of astrocytes in the model group was remarkably less than the sham-operated group. Compared to the model and sham-operated groups,the number of astrocytes significantly increased,and the cell body became larger,following treatment with low molecular weight heparin-superoxide dismutase conjugate.Astrocytes exhibited hypertrophy and hyperplasia,and the processes became longer and thicker. CONCLUSION:The low molecular weight heparin-superoxide dismutase conjugate may provide neuroprotection through astrocytic activation at the super-early stage of cerebral ischemia and reperfusion.
文摘BACKGROUND:Several studies have demonstrated that low molecular weight heparin-superoxide dismutase (LMWH-SOD) conjugate may exhibit good neuroprotective effects on cerebral ischemia/reperfusion injury though anticoagulation,decreasing blood viscosity,having anti-inflammatory activity,and scavenging oxygen free radicals. OBJECTIVE: To investigate the intervention effects of LMWH-SOD conjugate on serum levels of nitric oxide (NO),glutathione peroxidase (GSH-Px),and myeloperoxidase (MPO) following cerebral ischemia/reperfusion injury. DESIGN,TIME AND SETTING: A randomized,controlled,and neurobiochemical experiment was performed at the Institute of Biochemical Pharmacy,School of Pharmaceutical Sciences,Shandong University between April and July 2004. MATERIALS: A total of 60 Mongolian gerbils of either gender were included in this study. Total cerebral ischemia/reperfusion injury was induced in 50 gerbils by occluding bilateral common carotid arteries. The remaining 10 gerbils received a sham-operation (sham-operated group). Kits of SOD,NO,and MPO were sourced from Nanjing Jiancheng Bioengineering Institute,China. LMWH,SOD,and LMWH-SOD conjugates were provided by Institute of Biochemistry and Biotechnique,Shandong University,China. METHODS: Fifty successful gerbil models of total cerebral ischemia/reperfusion injury were evenly randomized to five groups: physiological saline,LMWH-SOD,SOD,LMWH + SOD,and LMWH. At 2 minutes prior to ischemia,0.5 mL/65 g physiological saline,20 000 U/kg LMWH-SOD conjugate,20 000 U/kg SOD,a mixture of SOD (20 000 U/kg) and LMWH (LMWH dose calculated according to weight ratio,LMWH: SOD=23.6:51),and LMWH (dose as in the LMWH + SOD group) were administered through the femoral artery in each above-mentioned group,respectively. MAIN OUTCOME MEASURES: Serum levels of NO,MPO,and GSH-Px. RESULTS: Compared with 10 sham-operated gerbils,the cerebral ischemia/reperfusion injury gerbils exhibited decreased serum levels of GSH-Px and increased serum levels of NO and MPO (P<0.01). The serum level of GSH-Px was significantly upregulated in all groups,in particular in the LMWH-SOD group (P<0.01),compared with the physiological saline group (P<0.05-0.01). Following medical treatment,serum levels of NO and MPO were significantly downregulated in all groups,in particular in the LMWH-SOD group (P<0.01). Serum levels of GSH-Px,NO,and MPO in the LMWH-SOD group were close to those in the sham-operated group (P > 0.05). CONCLUSION: In cerebral ischemia/reperfusion injury,LMWH-SOD conjugate exhibits stronger neuroprotective effects on free radical scavenging,inflammation inhibition,and cytotoxicity inhibition than simple or combined application of LMWH and SOD by downregulating NO and MPO levels and upregulating the GSH-Px level.
基金supported by the“Pioneer”and“Leading Goose”R&D Programs of Zhejiang(2022C03146)National Natural Science Foundation of China(22225606 and 22176029)Central Government Guided Local Science and Technology Development Fund(2021ZY1022)。
文摘To date,copper-based catalysts are one of the most prominent catalysts that can electrochemically reduce CO_(2)towards highvalue fuels or chemicals,such as ethylene,ethanol,and acetic acid.However,the chemically active feature of Cu-based catalysts hinders the understanding of the intrinsic catalytic active sites during the initial and the operative processes of electrochemical CO_(2)reduction(CO_(2)RR).The identification and engineering of active sites during the dynamic evolution of catalysts are thereby vital to further improve the activity,selectivity,and durability of Cu-based catalysts for high-performance CO_(2)RR.In this regard,four triggers for the dynamic evolution of catalysts were introduced in detail.Afterward,three typical active-site theories during the dynamic reconstruction of catalysts were discussed.In addition,the strategies in catalyst design were summarized according to the latest reports of Cu-based catalysts for CO_(2)RR,including the tuning of electronic structure,controlling of the external potential,and regulation of local catalytic environment.Finally,the conclusions and perspectives were provided to inspire more investigations and studies on the intrinsic active sites during the dynamic evolution of catalysts,which could promote the optimization of the catalyst system to further improve the performance of CO_(2)RR.
