Objective To construct a recombinant plasmid vector containing the distal fragment of the distal C-terminus (dDCT) of the Cav 1.2 channel,and express,extract,and purify dDCT protein and characterize its biological activity.Methods dDCT cDNA was ligated into the pGEX-6p-1 vector to create a recombinant plasmid that was subsequently transformed into Escherichia coli BL21 competent cells.Expression of GST-dDCT fusion protein from this plasmid was induced with isopropy-β-D-thiogalactoside,and the resulting protein was purified using glutathione-sepharose 4B beads.The biological activity of dDCT was analyzed by GST pull-down assay.Results The recombinant plasmid was verified by restriction enzyme digestion and sequencing.The concentration and purity of the dDCT protein,which was extracted by ultrasonication,were high enough to detect dDCT activity.The binding of dDCT to CT1 was determined to be concentration-dependent.Conclusion The recombinant dDCT plasmid was successfully constructed,providing the fundamental basis for future studies on mechanisms of Cav 1.2 channel autoregulation.

INTRODUCTION: Oropharyngeal swabs for diagnosis of COVID-19 often induce violent coughing, which can disperse infectious droplets onto providers. Incorrectly doffing personal protective equipment (PPE) increases the risk of transmission. A cheap, single-use variation of the face shield invented by a Singaporean team, SG Shield, aims to reduce this risk. This manikin study aimed to study the efficacy of the SG Shield in combination with standard PPE. METHODS: A person attired in full PPE whose face and chest was lined with grid paper stood in front of an airway manikin in an enclosed room. A small latex balloon containing ultraviolet fluorescent dye was placed in the oral cavity of the manikin and inflated until explosion to simulate a cough. Three study groups were tested: (a) control (no shield), (b) face shield and (c) SG Shield. The primary outcome was droplet dispersion, determined quantitatively by calculating the proportion of grid paper wall squares stained with fluorescent dye. The secondary outcome was the severity of provider contamination. RESULTS: The SG Shield significantly reduced droplet dispersion to 0% compared to the controls (99.0%, P = 0.001). The face shield also significantly reduced droplet contamination but to a lesser extent (80.0%) compared to the control group (P = 0.001). Although the qualitative severity of droplet contamination was significantly lower in both groups compared to the controls, the face shield group had more contamination of the provider's head and neck. CONCLUSION The manikin study showed that the SG Shield significantly reduces droplet dispersion to the swab provider's face and chest.
Humans ; Infectious Disease Transmission, Patient-to-Professional/prevention & control* ; COVID-19 ; Fluorescent Dyes ; Personal Protective Equipment ; Cough

OBJECTIVE：To in vestigate the effects of quercetin （Que）on the expressio n of angiotensin Ⅱ（AngⅡ）-induced myocardial contractile proteins of primary rats through angiotensin-converting enzyme 2-angiotensin-（1-7）-Mas （ACE2-Ang- （1-7）-Mas）axis. METHODS ：Cardiac tissue of rats aged 1-2 d were collected ，and primary cardiomyocytes were isolated and cultured. The gene silencing model of cardiomyocytes ACE2 was constructed. Experiments were divided into 12 groups. Among them，AngⅡ group，AngⅡ+ small interference RNA （siRNA）group，and Ang Ⅱ+ A 779 group were the model groups ；AngⅡ+ losartan group was positive control group ；AngⅡ+Que40 group，AngⅡ+Que80 group，AngⅡ+siRNA+Que40 group，AngⅡ+ siRNA+Que80 group，AngⅡ+A779+Que40 group and Ang Ⅱ+A779+Que80 group were the experimental groups ；blank group and siRNA group were set up. Ang Ⅱ concentration was 1×10－6 mol/L；siRNA final concentration was 50 nmol/L；Que concentration was 40 and 80 μmol/L；A779（Mas receptor inhibitor ）concentration was 1 μmol/L；losartan concentration was 1×10－4 mol/L. mRNA and protein expression of ACE 2，Ang-（1-7） and Mas in primary cardiomyocytes were detected ；the expressions of myocardial contractile proteins were also determined ，such as Na +/Ca2+ exchange channel （NCX），calcium pump （SERCA2a）， phosphoprotein （PLB）. RESULTS ：Compared with Ang Ⅱ group，mRNA expression of Mas was increased significantly in Ang Ⅱ + Que 80 group （P＜0.05）；mRNA expression of ACE2 and Mas were increased significantly in Ang Ⅱ + CZ0210-01） losartan group （P＜0.05）. Compared with Ang Ⅱ group，the 851136165@qq.com protein expression of ACE 2 and Ang- （1-7） were increased significantly in Ang Ⅱ+ Que 40 group（P＜0.05）；compared with Ang Ⅱ + siRNA group ，the protein expression of Ang-（1-7）were increased significantly in Ang Ⅱ+ siRNA+Que 40 group（P＜0.05）；compared with Ang Ⅱ+A779 group，the protein expression of Ang- （1-7）were increased significantly in Ang Ⅱ+A779+ Que 40 group（P＜0.05）. Compared with Ang Ⅱ group，the protein expression of NCX was decreased in Ang Ⅱ+Que40 group（P＜0.05），protein expression of NCX was reduced in Ang Ⅱ+ losartan group （P＜0.05）；compared with Ang Ⅱ+A779 group，the protein expression of NCX was decreased in Ang Ⅱ+A779+ Que80 group （P＜0.05）. CONCLUSIONS ：Que improves the expression of Ang Ⅱ -induced ACE 2-Ang-（1-7）-Mas axis in cardiomyocyte model to some extent ，so as to regulate myocardial contractile protein.

OBJECTIVE To explore the mechanism of Tingli dazao xiefei decoction on ventricular remodeling in model rats with heart failure after myocardial infarction. METHODS The rat model of heart failure after myocardial infarction was established by ligation of anterior descending branch of left coronary artery， which was divided into 8 groups： sham operation group， model group， A779 group （1 mg/kg）， A779 （1 mg/kg）+Tingli dazao xiefei decoction equivalent-dose group （0.8 g/kg）， A779 （1 mg/kg） +Tingli dazao xiefei decoction high-dose group （1.6 g/kg）， Tingli dazao xiefei decoction equivalent-dose group （0.8 g/kg）， Tingli dazao xiefei decoction high-dose group （1.6 g/kg） and losartan potassium group （10 mg/kg）. Each group was given equal volume of distilled water or corresponding drugs intragastrically for 4 weeks. Masson staining was used to determine the distribution of collagen fibers in rat myocardium. The content of hydroxyproline （Hyp） in myocardium was determined by alkaline hydrolyzation. The expressions of type Ⅰ and Ⅲ collagen （COLⅠ， COLⅢ）in myocardium were detected by immunohisto-chemistry. Myocardial fibrosis-related indexes such as matrix metalloproteinase-2 （MMP-2）， MMP-9， tissue inhibitor of metalloproteinase-1 （TIMP-1） and soluble suppression of tumorigenicity-2 （sST-2） were detected by ELISA. The protein expressions of angiotensin converting enzyme 2-angiotensin-（1-7）-Mas [ACE2-Ang-（1-7）-Mas] axis were detected by Western blot. RESULTS Compared with sham operation group， myocardial cells in model group and A779 group were disordered， collagen fiber deposition was significantly increased and myocardial fibrosis was obvious； the Hyp content and MMP-2， MMP-9， sST-2 levels were increased， and COL Ⅰ and COL Ⅲ positive expressions were significantly enhanced； TIMP-1 level， protein expressions of ACE2， Ang-（1-7） and Mas were significantly decreased （P＜0.05）. Compared with model group， above indexes of Tingli dazao xiefei decoction equivalent-dose and high-dose groups were improved to different extents. Compared with A779 group， A779+Tingli dazao xiefei decoction equivalent-dose and A779+high-dose groups could improve myocardial arrangement and collagen distribution， reduce the Hyp content and MMP-2， MMP-9 levels， reduce positive expressions of COL Ⅰ and COL Ⅲ （P＜0.05）， but couldn’t improve Ang-（1-7） and Mas protein expression. CONCLUSIONS Tingli dazao xiefei decoction can improve ventricular remodeling in myocardial failure model rats after myocardial infarction by improving the expression of ACE2- Ang（- 1-7）-Mas axis proteins.