The Na+ - K+ ATPase is an enzyme responsible for the active transport of Na+ and K+ in most eukaryotic cells. The aim of the present study was to determine the effect of Tachykinin neuropeptide, Neurokinin B (NKB) and...The Na+ - K+ ATPase is an enzyme responsible for the active transport of Na+ and K+ in most eukaryotic cells. The aim of the present study was to determine the effect of Tachykinin neuropeptide, Neurokinin B (NKB) and Amyloid beta fragment Aβ (25 - 35) on 17β estradiol (E2) treated aging female rat brain synaptosomes of different age groups, by assaying Na+ - K+ ATPase enzyme activity. An in vitro incubation of isolated synaptosomes with Aβ (25 - 35) showed toxic effects while NKB showed stimulating effect on the Na+ - K+ ATPase activity, and the combined NKB + Aβ (25 - 35) incubations showed a partial effect as compared to the Aβ (25 - 35) alone. To understand whether E2 affects the expression of Na+ - K+ ATPase molecules, we examined the expression of Na+ - K+ ATPase subunit α1 and β2 in E2 treated aging female rat brain synaptosomes. The enzyme was quantified by SDS PAGE in control and E2 treated rat brain. We observed that the expression of α1 and β2 Na+ - K+ ATPase molecules increased and reversed to a normal level in E2 treated synaptosomes. These results confirmed that E2 increased turnover of Na+ - K+ ATPase molecules in aging rat brain. The present findings also suggest a possible role of NKB with E2 in the age related changes in the brain.展开更多
Death due to scorpion envenoming syndrome is a common event in tropical and subtropical countries. Severe scorpion envenoming causes autonomic storm, massive release of catecholamines, counter-regulatory hormones, sup...Death due to scorpion envenoming syndrome is a common event in tropical and subtropical countries. Severe scorpion envenoming causes autonomic storm, massive release of catecholamines, counter-regulatory hormones, suppressed insulin/hyperinsulinemia, acute myocarditis, hyperglycemia, increased free fatty Acid levels, acute pancreatitis, disseminated intra-vascular coagulation, acute pulmonary oedema and death. Severe scorpion envenoming causes cardiac sarcolemmal defects displayed by alterations in Na+ - K+ ATPase, Mg++ ATPase and Ca2+ ATPase activities, inhibition of erythrocyte Na+ - K+ ATPase activities, hyperkalemia and may result in death. Based on our animal experiments in which insulin administration reversed the metabolic and ECG changes induced by scorpion envenoming and treating the poisonous scorpion sting victims with insulin, we consider that insulin has a primary metabolic role in preventing and reversing acute myocarditis, the cardiovascular, haemodynamic, and neurological manifestations and pulmonary oedema induced by scorpion envenoming. Administration of insulin-glucose infusion to scorpion sting victims appears to be the physiological basis for the control of the metabolic response when that has become a determinant to survival. Continuous infusion of regular crystalline insulin should be given at the rate of 0.3 U/g glucose and glucose at the rate of 0.1 g/kg body weight/hour, for 48 - 72 hours, with supplementation of potassium as needed and maintenance of fluid, electrolytes and acid-base balance. The observation of cardiac sarcolemmal defects and physiological basis of various patho-physiological mechanisms involved in the genesis of scorpion envenoming syndrome and its reversal (in the experimental animals and scorpion sting victims) by administration of insulin are reviewed.展开更多
Improving the alkali resistance of catalysts for selective catalytic reduction of NO_(x) with NH_(3) is still a challenge.In this work,the co-modification with Fe,Ce and sulfates on V_(2)O_(5)-WO_(3)/TiO_(2) catalysts...Improving the alkali resistance of catalysts for selective catalytic reduction of NO_(x) with NH_(3) is still a challenge.In this work,the co-modification with Fe,Ce and sulfates on V_(2)O_(5)-WO_(3)/TiO_(2) catalysts(denoted as xSFeCeVWTi) significantly enhances its alkali resistance with K element as a representative.A series of xSFeCeVWTi catalysts was synthesized by wet impregnation with designed 0.05Fe/V, 1.5Ce/V and different S/V molar ratios x.The NO_(x) conversion and K resistance of xSFeCeVWTi catalysts increase with the increase of loading amounts of sulfates but no longer further increase as the sulfates load is excessive to block the pores of catalysts and hinder the adsorption of reactants.The optimal modified catalyst in about 2.2S/V actual loading ratio,corresponding to 10.5SFeCeVWTi sample,shows over 99.0%NO_(x) conversion and N_(2) selectivity at 300-400℃ after K-poisoning.The interaction between Fe,Ce and V improves its redox ability but slightly weakens surface acidity,while the proper amount of sulfate species enriches surface Br?nsted acid sites but attenuates its redox capability.However,a balance of redox capacity and surface acidity,caused by Fe,Ce and sulfate co-modification,contributes to the excellent K resistance of 10.5SFeCeVWTi catalyst.Finally,the change of physicochemical properties influences the reaction mechanism which follows the Eley-Rideal mechanism on 10.SSFeCeVWTi catalyst.These results show that the co-modification with Fe,Ce and sulfates is a good way to improve the alkali tolerance of V_(2)O_(5)-WO_(3)/TiO_(2) catalyst in industrial applications.展开更多
文摘The Na+ - K+ ATPase is an enzyme responsible for the active transport of Na+ and K+ in most eukaryotic cells. The aim of the present study was to determine the effect of Tachykinin neuropeptide, Neurokinin B (NKB) and Amyloid beta fragment Aβ (25 - 35) on 17β estradiol (E2) treated aging female rat brain synaptosomes of different age groups, by assaying Na+ - K+ ATPase enzyme activity. An in vitro incubation of isolated synaptosomes with Aβ (25 - 35) showed toxic effects while NKB showed stimulating effect on the Na+ - K+ ATPase activity, and the combined NKB + Aβ (25 - 35) incubations showed a partial effect as compared to the Aβ (25 - 35) alone. To understand whether E2 affects the expression of Na+ - K+ ATPase molecules, we examined the expression of Na+ - K+ ATPase subunit α1 and β2 in E2 treated aging female rat brain synaptosomes. The enzyme was quantified by SDS PAGE in control and E2 treated rat brain. We observed that the expression of α1 and β2 Na+ - K+ ATPase molecules increased and reversed to a normal level in E2 treated synaptosomes. These results confirmed that E2 increased turnover of Na+ - K+ ATPase molecules in aging rat brain. The present findings also suggest a possible role of NKB with E2 in the age related changes in the brain.
文摘Death due to scorpion envenoming syndrome is a common event in tropical and subtropical countries. Severe scorpion envenoming causes autonomic storm, massive release of catecholamines, counter-regulatory hormones, suppressed insulin/hyperinsulinemia, acute myocarditis, hyperglycemia, increased free fatty Acid levels, acute pancreatitis, disseminated intra-vascular coagulation, acute pulmonary oedema and death. Severe scorpion envenoming causes cardiac sarcolemmal defects displayed by alterations in Na+ - K+ ATPase, Mg++ ATPase and Ca2+ ATPase activities, inhibition of erythrocyte Na+ - K+ ATPase activities, hyperkalemia and may result in death. Based on our animal experiments in which insulin administration reversed the metabolic and ECG changes induced by scorpion envenoming and treating the poisonous scorpion sting victims with insulin, we consider that insulin has a primary metabolic role in preventing and reversing acute myocarditis, the cardiovascular, haemodynamic, and neurological manifestations and pulmonary oedema induced by scorpion envenoming. Administration of insulin-glucose infusion to scorpion sting victims appears to be the physiological basis for the control of the metabolic response when that has become a determinant to survival. Continuous infusion of regular crystalline insulin should be given at the rate of 0.3 U/g glucose and glucose at the rate of 0.1 g/kg body weight/hour, for 48 - 72 hours, with supplementation of potassium as needed and maintenance of fluid, electrolytes and acid-base balance. The observation of cardiac sarcolemmal defects and physiological basis of various patho-physiological mechanisms involved in the genesis of scorpion envenoming syndrome and its reversal (in the experimental animals and scorpion sting victims) by administration of insulin are reviewed.
基金Project supported by Fujian Provincial Department of Science and Technology,China (2020Y0085)Youth Innovation Promotion Association,Chinese Academy of Sciences (2020309)the Cultivating Project of Strategic Priority Research Program of Chinese Academy of Sciences (XDPB1902)。
文摘Improving the alkali resistance of catalysts for selective catalytic reduction of NO_(x) with NH_(3) is still a challenge.In this work,the co-modification with Fe,Ce and sulfates on V_(2)O_(5)-WO_(3)/TiO_(2) catalysts(denoted as xSFeCeVWTi) significantly enhances its alkali resistance with K element as a representative.A series of xSFeCeVWTi catalysts was synthesized by wet impregnation with designed 0.05Fe/V, 1.5Ce/V and different S/V molar ratios x.The NO_(x) conversion and K resistance of xSFeCeVWTi catalysts increase with the increase of loading amounts of sulfates but no longer further increase as the sulfates load is excessive to block the pores of catalysts and hinder the adsorption of reactants.The optimal modified catalyst in about 2.2S/V actual loading ratio,corresponding to 10.5SFeCeVWTi sample,shows over 99.0%NO_(x) conversion and N_(2) selectivity at 300-400℃ after K-poisoning.The interaction between Fe,Ce and V improves its redox ability but slightly weakens surface acidity,while the proper amount of sulfate species enriches surface Br?nsted acid sites but attenuates its redox capability.However,a balance of redox capacity and surface acidity,caused by Fe,Ce and sulfate co-modification,contributes to the excellent K resistance of 10.5SFeCeVWTi catalyst.Finally,the change of physicochemical properties influences the reaction mechanism which follows the Eley-Rideal mechanism on 10.SSFeCeVWTi catalyst.These results show that the co-modification with Fe,Ce and sulfates is a good way to improve the alkali tolerance of V_(2)O_(5)-WO_(3)/TiO_(2) catalyst in industrial applications.
