BACKGROUND The increased stroke risk associated with atrial fibrillation(AF)burden exceeding 5 min is a matter of debate.In addition,the potential linear or nonlinear relationship between AF burden and stroke risk has...BACKGROUND The increased stroke risk associated with atrial fibrillation(AF)burden exceeding 5 min is a matter of debate.In addition,the potential linear or nonlinear relationship between AF burden and stroke risk has been largely unexplored.AIM To determine the association between AF burden>5 min and the increased risk of stroke and explore the potential dose-response relationship between these two factors.METHODS Sixteen studies from six databases with 53141 subjects(mean age 65 years)were included.Fifteen studies were observational studies,and one was a randomized controlled trial study.The potential nonlinear dose-response association was characterized using a restricted cubic splines regression model.AF burden for each 1 h and 2 h was associated with an increased risk of stroke.Trial sequential analysis with a random-effect model was used to evaluate the robustness of the evidence from the included 16 studies.RESULTS AF burden>5 min was associated with an increased risk of clinical AF[adjusted risk ratio(RR)=4.18,95%confidence interval(CI):2.26-7.74].However,no association was found with an increased risk of all-cause mortality(adjusted RR=1.55,95%CI:0.87-2.75).Patients with AF burden>5 min had an increased risk of stroke(adjusted RR=2.49,95%CI:1.79-3.47).Moreover,a dose-response analysis showed that the increased stroke risk was paralleled by an increase in AF burden at a rate of 2.0%per hour(Pnonlinear=0.656,RR=1.02,95%CI:1.01-1.03).Trial sequential analysis provided robust evidence of the association between AF burden>5 min and an increased risk of stroke.CONCLUSION AF burden was a significant risk factor for clinical AF and future stroke.A significant linear association was documented between increased AF burden and risk of future stroke.展开更多
Phytochelatins （PCs） play an important role in heavy metal resistance and accumulation. To reduce the accumulation of cadmium （Cd） in rice seeds, the expression of phytochelatin synthase （PCS） gene OsPCS1 was su...Phytochelatins （PCs） play an important role in heavy metal resistance and accumulation. To reduce the accumulation of cadmium （Cd） in rice seeds, the expression of phytochelatin synthase （PCS） gene OsPCS1 was suppressed by RNA interference （RNAi）. A hairpin construct of a PCS fragment was designed in the pRNAi-OsPCS1 under the control of ZMM1, a seed-specific promoter from maize. The construct was introduced into rice （japonica） through Agrobacterium tumefaciens. The RNAi rice plantlets were selected and cultivated in pots exposured to 10 mg/kg Cd. The transcriptional level of OsPCS1 declined in seeds of some RNAi rice compared to the wild type. As a result Cd accumulation was reduced by about half in the seeds of RNAi rice. As expected, no apparent difference of growth appeared between RNAi and wild-type plants. The results suggest that this new approach can be used to control heavy metal accumulation in crops.展开更多
Bermudagrass （Cynodon dactylon L. cv. Goldensun） is highly resistant to and accumulates large amounts of cadmium （Cd）. A phytochelatin synthase （PCS） cDNA （CdPCS1） was isolated from this grass by rapid amplifi...Bermudagrass （Cynodon dactylon L. cv. Goldensun） is highly resistant to and accumulates large amounts of cadmium （Cd）. A phytochelatin synthase （PCS） cDNA （CdPCS1） was isolated from this grass by rapid amplification of cDNA ends. The putative CdPCS1 protein shared a high homology with PCS from other plants, with 79% homology at the N-terminal and 47% homology at the C-terminah However, 16 Cys residues were found at the C-terminal of CdPCS1, and among these residues, three positions were different from other PCS proteins. Semiquantitative reverse transcription-polymerase chain reaction analysis showed that Cd stress induced CdPCS1 expression in both roots and leaves in Bermudagrass. We verified that CdPCS1 plays an important role in Cd tolerance in yeast cells by expressing the gene in ABDE1, a Cdsensitive mutant. CdPCS1 was then introduced into tobacco plants. The phytochelatin level in some transgenic tobacco lines increased 3.88-fold more than in wild type plants and Cd accumulation in these transgenic plants was enhanced 3.21-fold accordingly. The results suggested that CdPCS1 could be used as a gene element for phytoremediation in the future.展开更多
基金Supported by National Natural Science Foundation of China,No.81673259Natural Science Foundation of Jiangsu Province,China,No.BK20161435.
文摘BACKGROUND The increased stroke risk associated with atrial fibrillation(AF)burden exceeding 5 min is a matter of debate.In addition,the potential linear or nonlinear relationship between AF burden and stroke risk has been largely unexplored.AIM To determine the association between AF burden>5 min and the increased risk of stroke and explore the potential dose-response relationship between these two factors.METHODS Sixteen studies from six databases with 53141 subjects(mean age 65 years)were included.Fifteen studies were observational studies,and one was a randomized controlled trial study.The potential nonlinear dose-response association was characterized using a restricted cubic splines regression model.AF burden for each 1 h and 2 h was associated with an increased risk of stroke.Trial sequential analysis with a random-effect model was used to evaluate the robustness of the evidence from the included 16 studies.RESULTS AF burden>5 min was associated with an increased risk of clinical AF[adjusted risk ratio(RR)=4.18,95%confidence interval(CI):2.26-7.74].However,no association was found with an increased risk of all-cause mortality(adjusted RR=1.55,95%CI:0.87-2.75).Patients with AF burden>5 min had an increased risk of stroke(adjusted RR=2.49,95%CI:1.79-3.47).Moreover,a dose-response analysis showed that the increased stroke risk was paralleled by an increase in AF burden at a rate of 2.0%per hour(Pnonlinear=0.656,RR=1.02,95%CI:1.01-1.03).Trial sequential analysis provided robust evidence of the association between AF burden>5 min and an increased risk of stroke.CONCLUSION AF burden was a significant risk factor for clinical AF and future stroke.A significant linear association was documented between increased AF burden and risk of future stroke.
基金Supported by the National Program of Research and Development of Transgenic Plants of China （JY03A2001） and the National Natural Science Foundation of China （30570138 and 30370127）.The authors thank Professors Kang Chong and Zheng Meng of the Institute of Botany, the Chinese Academy of Sciences, for kindly providing the vectors of pTCK303 and pKZMM1.
文摘Phytochelatins （PCs） play an important role in heavy metal resistance and accumulation. To reduce the accumulation of cadmium （Cd） in rice seeds, the expression of phytochelatin synthase （PCS） gene OsPCS1 was suppressed by RNA interference （RNAi）. A hairpin construct of a PCS fragment was designed in the pRNAi-OsPCS1 under the control of ZMM1, a seed-specific promoter from maize. The construct was introduced into rice （japonica） through Agrobacterium tumefaciens. The RNAi rice plantlets were selected and cultivated in pots exposured to 10 mg/kg Cd. The transcriptional level of OsPCS1 declined in seeds of some RNAi rice compared to the wild type. As a result Cd accumulation was reduced by about half in the seeds of RNAi rice. As expected, no apparent difference of growth appeared between RNAi and wild-type plants. The results suggest that this new approach can be used to control heavy metal accumulation in crops.
基金Supported by the Special Project of Transgenic Plants Research (JY03A2001)
文摘Bermudagrass （Cynodon dactylon L. cv. Goldensun） is highly resistant to and accumulates large amounts of cadmium （Cd）. A phytochelatin synthase （PCS） cDNA （CdPCS1） was isolated from this grass by rapid amplification of cDNA ends. The putative CdPCS1 protein shared a high homology with PCS from other plants, with 79% homology at the N-terminal and 47% homology at the C-terminah However, 16 Cys residues were found at the C-terminal of CdPCS1, and among these residues, three positions were different from other PCS proteins. Semiquantitative reverse transcription-polymerase chain reaction analysis showed that Cd stress induced CdPCS1 expression in both roots and leaves in Bermudagrass. We verified that CdPCS1 plays an important role in Cd tolerance in yeast cells by expressing the gene in ABDE1, a Cdsensitive mutant. CdPCS1 was then introduced into tobacco plants. The phytochelatin level in some transgenic tobacco lines increased 3.88-fold more than in wild type plants and Cd accumulation in these transgenic plants was enhanced 3.21-fold accordingly. The results suggested that CdPCS1 could be used as a gene element for phytoremediation in the future.
