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An innovative,ternary nanocomposite composed of overoxidized poly(3,4-ethylenedioxythiophene)(OPEDOT),gold nanoparticles (AuNPs),and electrochemically reduced graphene oxide (ERGO) was prepared on a glassy carbon electrode (GCE) (OPEDOT-AuNPs-ERGO/GCE) through homogeneous chemical reactions and heterogeneous electrochemical methods.The morphology,composition,and structure of this nanocomposite were characterized by transmission electron microscopy,scanning electron microscopy,X-ray diffraction,and X-ray photoelectron spectroscopy.The electrochemical properties of the OPEDOT-AuNPs-ERGO/GCE were investigated by cyclic voltammetry using potassium ferricyanide and hexaammineruthenium(Ⅲ) chloride redox probe systems.This modified electrode shows excellent electro-catalytic activity for dopamine (DA) and uric acid (UA) under physiological pH conditions,but inhibits the oxidation of ascorbic acid (AA).Linear voltammetric responses were obtained when DA concentrations of approximately 4.0-100 μM and UA concentrations of approximately 20-100 μM were used.The detection limits (S/N=3) for DA and UA were 1.0 and 5.0 μ.M,respectively,under physiological conditions and in the presence of 1.0 mM of AA.This developed method was applied to the simultaneous detection of DA and UA in human urine,where satisfactory recoveries from 96.7％ to 105.0％were observed.This work demonstrates that the developed OPEDOT-AuNPs-ERGO ternary nano-composite,with its excellent ion-selectivity and electro-catalytic activity,is a promising candidate for the simultaneous detection of DA and UA in the presence of AA in physiological and pathological studies.
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Objective To investigate the expression of α-smooth muscle actin (α-SMA)in patients with valvular atrial fibrillation and study the relationship betweenα-SMA and atrial fibrosis in patients with valvular atrial fibrillation (AF).Methods For this study we enrolled 84 consecutive patients with rheumatic heart disease who were to receive cardiac surgery.The patients were divided into AF group (AF,n=39)and sinus rhythm group (SR, n=45).Their clinical data including baseline demographics,routine laboratory test and echocardiographics were collected before surgery.The right atrial tissue (0 .3-0 .5 cm3 )was disserted during the surgery.Right atrial fibrosis was observed by Masson staining.The mRNA expression ofα-SMA in atrial tissue were determined by Real-time quantitative PCR.Western blot was used to measure the protein expression ofα-SMA in atrial tissue.Results The two groups did not significantly differ in sex ratio,age,blood pressure,blood biochemical indicators or other aspects of medical history (P>0.05).However,left and right atrium diameters in AF group were significantly larger than those in SR group (P<0 .05 ).Masson staining suggested that collagen volume fraction and collagen content were significantly higher in AF group than in SR group (P<0 .05 ).The mRNA and protein expressions ofα-SMA in right atrial tissue were obviously higher in AF group than in SR group (coefficients P<0 .05 ).The mRNA and protein expressions ofα-SMA from right atrial tissue in the 84 patients were positively correlated with collagen content (coefficients of 0.587 and 0.607;P=0.029,0.014,respectively).Conclusion There is significant atrial fibrosis in patients with valvular atrial fibrillation,which is closely related to up-regulated expression ofα-SMA gene.
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Objective:To investigate the expression of fibrillin-1 (FBN-1) in the atrium tissue of the patients with rheumatic heart valve disease complicated with atrial fibrillation(AF), and to explore its relationship with atrial fibrosis in the patients with valvular atrial fibrillation.Methods:Eighty-four consecutive patients with rheumatic heart valve disease underwent cardiac surgery were enrolled in this study.The patients were divided into AF group(n=39) and sinus rhythm group(SR group, n=45).The clinical data of patients were collected before operation.The right atrium tissue (0.3-0.5 mm3) was disserted during operation.The degrees of right atrial fibrosis of the patients in two groups were observed by Masson staining.Western blotting method was used to measure the protein expressions of FBN-1 in atrium tissue of the patients in two groups.Results:There were no significant differences in the gender ratio, age, blood pressure, blood biochemical indicators and other aspects of medical history between two groups(P>0.05);the diameters of left and right atrium of the patients in AF group were significantly larger than those in SR group(P<0.05).The Masson staining results showed that there was obvious fibrosis in AF group, and the collagen volume fraction and collagen level in AF group were significantly higher than those in SR group (P<0.05).The expression level of FBN-1 in right atrium tissue in AF group was obviously higher than that in SR group(P<0.05).The expression level of FBN-1 protein in right atrium tissue of the patients with valvular atrial fibrillation was positively correlated with the collagen level(r=0.544,P=0.021).Conclusion:There is obvious atrium fibrosis in the patients with valvular atrial fibrillation;it is closely related to the up-regulation of the expression of FBN-1 gene.
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Objective To reveal the role of serum ACE2/Ang (1-7)in the occurrence of atrial fibrillation (AF)and find new targets for the prevention and treatment of AF by analyzing the correlation between the serum concentration of ACE2/Ang (1-7 )in patients with rheumatic valvular heart disease and the occurrence of AF. Methods We collected the basic clinical information and peripheral venous blood of patients with rheumatic heart valve disease (totally 46 patients,including 24 with AF and 22 with SR).ELISA method was used to detect the serum concentration of ACE2,Ang (1-7)and AngⅡ in the serum samples.Then the differences and correlation between the two groups were analyzed.Results In the AF group ① the diameter of the left atrium was significantly greater than that in the SR group [(60.70±3.08 vs.48.15±2.16)mm,P<0.05];② the serum concentration of AngⅡ was significantly higher than that in the SR group [(45.88±2.87 vs.35.78±1.08)pg/mL, P<0.05],AngⅡ and left atrium diameter were positively correlated (Pearson test,P<0.05);③ the serum concentrations of ACE2 [(7.87±0.74 vs.11.65±0.57)U/L,P<0.05]and Ang (1-7)[(146.05±17.61 vs. 321.71±36.50)pg/mL,P<0.05]were significantly lower than those in the SR group,and negatively correlated with left atrium diameter (Pearson test,P<0.05);④ the serum concentration of Ang (1-7)was negatively correlated with AngⅡ concentration (Pearson test,P<0.05).Conclusion For patients with rheumatic valvular heart disease,ACE2/Ang (1-7 )may play a protective role in the occurrence of AF via antagonizing AngⅡ and inhibiting atrial remodeling.
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AIM:To study the effects of extracellular potassium on the protein expression of wild-type HERG and its mutant L539fs/47.METHODS:Wild-type HERG (WT) or its mutant HERG-L539fs/47 (MT) were transfected into HEK293 cells for 36 h.The cells were incubated in different media containing 0.8, 4.3 or 10 mmol/L potassium.Af-ter 6 h of incubation, the protein expression of HERG was detected by flow cytometry.After 12 h of incubation, the locali-zation and quantity of the proteins were detected by laser confocal imaging and Western blot.RESULTS: Different from the retention of mutant protein in cytoplasm, wild-type HERG protein was mainly distributed in the cell membrane.The 2 proteins both increased with the changes of extracellular potassium.Flow cytometry showed that the fluorescence in the 2 groups both increased with the changes of extracellular potassium ( P<0.01 ) .The fluorescence in WT group was signifi-cantly higher than that in MT group (P<0.01).Western blot showed that mutant HERG protein included only one 60 kD band, different from the 135 kD and 155 kD bands in wild-type HERG, which were affected by the changes of extracellular potassium (P<0.05).CONCLUSION:The retention of HERG mutant L539fs/47 protein in the cytoplasm is more than wild-type HERG.Chronic high extracellular potassium keeps the stability of wild-type and mutant HERG proteins on the cell membrane.Chronic low potassium reduces the expression of HERG channel proteins in a time-dependent manner.