The establishment of reliable age in the lake sediment profile mainly depends on the AMS 14C dating technique.However,the presence of the 14C lake reservoir effects(LREs)restricted for using radiocarbon dating in lake...The establishment of reliable age in the lake sediment profile mainly depends on the AMS 14C dating technique.However,the presence of the 14C lake reservoir effects(LREs)restricted for using radiocarbon dating in lake sediment,especially in dry and cold areas with a scarce plant cover in the Qinghai-Tibet Plateau.Hence,the discussion of influence factors of LREs is crucial.This paper selected 15 lakes(17 sediment and 3 plant samples)in the Qinghai-Tibet Plateau to examine the distribution characteristics of the modern LREs and their main influencing factors.In our study area,14 lakes were all affected by the LREs.The minimum 14C year is 5900 a BP towards the deep water area,whereas the maximum 14C year is up to 7185 a BP in the margins of Lake Heihai.The maximum 14C year is up to 7750 a BP,and the minimum 14C year is present-day carbon in the 15 lakes.One further study indicated that the LRE differences in individual lake are mostly owing to the contribution of exogenous carbonate.The results displayed that the LREs tended to increase with the increase of the salinity,moreover,the LREs of saltwater lakes or salt lakes were significantly larger than freshwater lakes due to the possible supply of old total dissolved inorganic carbon with a long residence time in the lakes.Moreover,the contribution of calcite played a significant role on the LREs.Additionally,the LREs differences are affected by the source of organic matter.The lake with groundwater supply shows large LRE due to likely being influenced by crustal and ancient CO_(2) uprising.展开更多
Background The traditional Chinese medicine injury, but the mechanism of its action is not we protective role of Tongxinluo. Tongxinluo can protect myocardium against documented. We examined the involvement schaemia/r...Background The traditional Chinese medicine injury, but the mechanism of its action is not we protective role of Tongxinluo. Tongxinluo can protect myocardium against documented. We examined the involvement schaemia/reperfusion of nitric oxide in the Methods Miniswine were randomized to four groups of seven： sham, control, Tongxinluo and Tongxinluo coadministration with a nitric oxide synthase inhibitor N^ωnitro-L-arginine （L-NNA, 10 mg/kg i.v.）. Three hours after administration of Tongxinluo, the animals were anaesthetised and the left anterior descending coronary artery ligated and maintained in situ for 90 minutes followed by 3 hours of reperfusion before death. Area of no reflow and necrosis and risk region were determined pathologically by planimetry. The degree of neutrophil accumulation in myocardium was obtained by measuring myeloperoxidase activity and histological analysis. Myocardial endothelial nitric oxide synthase activity and vascular endothelial cadherin content were measured by colorimetric method and immunoblotting analysis respectively. Results Tongxinluo significantly increased the local blood flow and limited the infarct and size of no reflow. Tongxinluo also attenuated myeloperoxidase activity and neutrophil accumulation in histological sections and maintained the level of vascular endothelial cadherin and endothelial nitric oxide synthase activity in the reflow region when compared with control group. The protection of Tongxinluo was counteracted by coadministration with L-NNA. Conclusions Tongxinluo may limit myocardial ischaemia and protect the heart against reperfusion injury. Tongxinluo regulates synthesis of nitric oxide by altering activity of endothelial nitric oxide synthase.展开更多
Background Treatment of ischemic heart disease remains an important challenge, though there have been enormous progresses in cardiovascular therapeutics. This study was conducted to evaluate whether Tongxinluo （TXL）...Background Treatment of ischemic heart disease remains an important challenge, though there have been enormous progresses in cardiovascular therapeutics. This study was conducted to evaluate whether Tongxinluo （TXL） treatment around the transplantation of mesenchymal stem cells （MSCs） can improve survival and subsequent activities of implanted cells in swine hearts with acute myocardial infarction （AMI） and reperfusion. Methods Twenty-eight Chinese mini-pigs were divided into four groups including a control group （n=7）; group 2, administration of low-close TXL alone from the 3rd day prior to AMI to the 4th day post transplantation （n=-7）; group 3, MSCs alone （n=-7） and group 4, TXL ＋ MSCs （n=7）. AMI models were made by occlusion of the left anterior descending coronary artery for 90 minutes. Autologous bone marrow-MSCs （3×10^7 cells/animal） were then injected into the post-infarct myocardium immediately after AMI and reperfusion. The survival and differentiation of implanted cells in vivo were detected by immunofluorescent analysis. The data of cardiac function were obtained at baseline （1 week after transplantation） and endpoint （6 weeks after transplantation） by single photon emission computed tomography （SPECT） and magnetic resonance imaging （MRI）. Apoptosis was detected by TUNEL assay and the oxidative stress level was investigated in the post-infarct myocardium at endpoint. Results At endpoint, there was less fibrosis and inflammatory cell infiltration with more surviving myocardium in group 4 than in the control group. In group 4 the survival and differentiation of implanted MSCs were significantly improved more than that seen in group 3 alone （P〈0.0001）; the capillary density was also significantly greater than in the control group, group 2 or 3 both in the infarcted zone （P〈0.0001） and the peri-infarct zone （P〈0.0001）. MRI showed that parameters at baseline were not significantly different between the 4 groups. At endpoint, regional wall thickening and the left ventricular ejection fraction were increased while the left ventricular mass index, dyskinetic segments and infarcted size were decreased only in group 4 compared with control group （P〈0.0001）. SPECT showed that the area of perfusion defect was significantly decreased at endpoint only in group 4 compared with control group （P〈0.0001）. TUNEL assay indicated that TXL administration significantly decreased cell apoptosis in peri-infarct myocardium in groups 2 and 4. Furthermore, superoxide dismutase （SOD） significantly increased and malondialdehyde （MDA） decreased in groups 2 and 4 by the administration of TXL. Conclusions Our study demonstrates the following： （1） immediate intramyocardial injection of MSCs after AMI and reperfusion resulted in limited survival and differentiation potential of implanted cells in vivo, thus being incapable of beneficially affecting post-hearts; （2） TXL-facilitation resulted in a significant survival and differentiation potential of implanted cells in vivo via inhibition of apoptosis and oxidative stress, accompanied by significant benefits in cardiac function.展开更多
基金The work was supported by a grant from Research Fund for the Doctoral Program of Higher Education of East China University of Technology(DHBK2019012)Key Laboratory for Digital Land and Resources of Jiangxi Province,East China University of Technology(DLLJ202018)Key Research and Development Program of Jiangxi Province(20181BBG70037).
文摘The establishment of reliable age in the lake sediment profile mainly depends on the AMS 14C dating technique.However,the presence of the 14C lake reservoir effects(LREs)restricted for using radiocarbon dating in lake sediment,especially in dry and cold areas with a scarce plant cover in the Qinghai-Tibet Plateau.Hence,the discussion of influence factors of LREs is crucial.This paper selected 15 lakes(17 sediment and 3 plant samples)in the Qinghai-Tibet Plateau to examine the distribution characteristics of the modern LREs and their main influencing factors.In our study area,14 lakes were all affected by the LREs.The minimum 14C year is 5900 a BP towards the deep water area,whereas the maximum 14C year is up to 7185 a BP in the margins of Lake Heihai.The maximum 14C year is up to 7750 a BP,and the minimum 14C year is present-day carbon in the 15 lakes.One further study indicated that the LRE differences in individual lake are mostly owing to the contribution of exogenous carbonate.The results displayed that the LREs tended to increase with the increase of the salinity,moreover,the LREs of saltwater lakes or salt lakes were significantly larger than freshwater lakes due to the possible supply of old total dissolved inorganic carbon with a long residence time in the lakes.Moreover,the contribution of calcite played a significant role on the LREs.Additionally,the LREs differences are affected by the source of organic matter.The lake with groundwater supply shows large LRE due to likely being influenced by crustal and ancient CO_(2) uprising.
文摘Background The traditional Chinese medicine injury, but the mechanism of its action is not we protective role of Tongxinluo. Tongxinluo can protect myocardium against documented. We examined the involvement schaemia/reperfusion of nitric oxide in the Methods Miniswine were randomized to four groups of seven： sham, control, Tongxinluo and Tongxinluo coadministration with a nitric oxide synthase inhibitor N^ωnitro-L-arginine （L-NNA, 10 mg/kg i.v.）. Three hours after administration of Tongxinluo, the animals were anaesthetised and the left anterior descending coronary artery ligated and maintained in situ for 90 minutes followed by 3 hours of reperfusion before death. Area of no reflow and necrosis and risk region were determined pathologically by planimetry. The degree of neutrophil accumulation in myocardium was obtained by measuring myeloperoxidase activity and histological analysis. Myocardial endothelial nitric oxide synthase activity and vascular endothelial cadherin content were measured by colorimetric method and immunoblotting analysis respectively. Results Tongxinluo significantly increased the local blood flow and limited the infarct and size of no reflow. Tongxinluo also attenuated myeloperoxidase activity and neutrophil accumulation in histological sections and maintained the level of vascular endothelial cadherin and endothelial nitric oxide synthase activity in the reflow region when compared with control group. The protection of Tongxinluo was counteracted by coadministration with L-NNA. Conclusions Tongxinluo may limit myocardial ischaemia and protect the heart against reperfusion injury. Tongxinluo regulates synthesis of nitric oxide by altering activity of endothelial nitric oxide synthase.
基金This work was supported by the grants from the National Basic Research Program(973 Program)Ministry of Science and Technology,China(No.2005CB523303)
文摘Background Treatment of ischemic heart disease remains an important challenge, though there have been enormous progresses in cardiovascular therapeutics. This study was conducted to evaluate whether Tongxinluo （TXL） treatment around the transplantation of mesenchymal stem cells （MSCs） can improve survival and subsequent activities of implanted cells in swine hearts with acute myocardial infarction （AMI） and reperfusion. Methods Twenty-eight Chinese mini-pigs were divided into four groups including a control group （n=7）; group 2, administration of low-close TXL alone from the 3rd day prior to AMI to the 4th day post transplantation （n=-7）; group 3, MSCs alone （n=-7） and group 4, TXL ＋ MSCs （n=7）. AMI models were made by occlusion of the left anterior descending coronary artery for 90 minutes. Autologous bone marrow-MSCs （3×10^7 cells/animal） were then injected into the post-infarct myocardium immediately after AMI and reperfusion. The survival and differentiation of implanted cells in vivo were detected by immunofluorescent analysis. The data of cardiac function were obtained at baseline （1 week after transplantation） and endpoint （6 weeks after transplantation） by single photon emission computed tomography （SPECT） and magnetic resonance imaging （MRI）. Apoptosis was detected by TUNEL assay and the oxidative stress level was investigated in the post-infarct myocardium at endpoint. Results At endpoint, there was less fibrosis and inflammatory cell infiltration with more surviving myocardium in group 4 than in the control group. In group 4 the survival and differentiation of implanted MSCs were significantly improved more than that seen in group 3 alone （P〈0.0001）; the capillary density was also significantly greater than in the control group, group 2 or 3 both in the infarcted zone （P〈0.0001） and the peri-infarct zone （P〈0.0001）. MRI showed that parameters at baseline were not significantly different between the 4 groups. At endpoint, regional wall thickening and the left ventricular ejection fraction were increased while the left ventricular mass index, dyskinetic segments and infarcted size were decreased only in group 4 compared with control group （P〈0.0001）. SPECT showed that the area of perfusion defect was significantly decreased at endpoint only in group 4 compared with control group （P〈0.0001）. TUNEL assay indicated that TXL administration significantly decreased cell apoptosis in peri-infarct myocardium in groups 2 and 4. Furthermore, superoxide dismutase （SOD） significantly increased and malondialdehyde （MDA） decreased in groups 2 and 4 by the administration of TXL. Conclusions Our study demonstrates the following： （1） immediate intramyocardial injection of MSCs after AMI and reperfusion resulted in limited survival and differentiation potential of implanted cells in vivo, thus being incapable of beneficially affecting post-hearts; （2） TXL-facilitation resulted in a significant survival and differentiation potential of implanted cells in vivo via inhibition of apoptosis and oxidative stress, accompanied by significant benefits in cardiac function.
