Objective: To develop a polyvinylidene fluoride (PVDF)-based instrument which may be used to measure bite force in natural teeth as well as in denture. Methods: The PVDF film was used as transducer. Electricity amplifier, lowpass filter, secondary magnifier in metrical circuit, and collection with disposal system were employed to produce the instrument for bite force measurement. The demarcating system was MTS-858. The instrument was used to measure the dynamic force in laterotrusion in 9 volunteers with Angle I occlusion. Results: The instrument was produced.By the used of the instrument the peak value of bite force (N) in the 9 subjects was 277.3?78.4 on the main functional side (MFS) and 258.7?83.3 on the subfunctional side (SFS).The time(ms) needed in the four phases on MFS was 65.6?7.3,354.4?66.1,116.3?25.0 and 226.9?35.8;that on SFS 67.5?6.6,394.4?65.3,141.9?25.6 and 167.5?41.9,respectively.Conclusion: The new system is steady and sensitive for bite force measurement.

Objective To explore the mechanism of macro-reentry atrial tachycardia and to guide catheter ablation using electroanatomic mapping system in 3 patients.Methods Three patients(two females),aged 51?12 years,with atrial tachycardia were included.The mean history of symptom was 19?11 years.Conventional electrophysiological study was performed to determine the location of atrial tachycardia before the three dimensional geometry reconstruction.After voltage and activation maps were constructed,the mechanism of tachycardia was analyzed and the slow conduction areas(critical isthmus) were verified.Radiofrequency energy was delivered using irrigated-tip catheter.Results Though there was no evidence to suggest structural heart diseases,scar areas were found in the mapped atria in all the three cases.The mechanism of atrial tachycardia was found to be counter-clockwise macro-reentry around tricuspid valve,counter-clockwise macro-reentry around superior vena cava,and figure "8" reentry in left atria in the 3 patients respectively.The respective critical isthmus was found to be between the lateral scar and tricuspid valve,the lateral scar and superior vena cava,and two scars on the left atria roof.Ablation in the critical isthmus terminated all tachycardia.There were no atrial tachycardia recurrence during a follow-up of 9-10 months.Conclusion The substrate and electrophysiological mechanism of macro-reentry atrial tachycardia could be identified clearly,and navigation ablation could be performed effectively under the guidence of electroanatomic mapping.

Objective:To screen the binding peptide against adenovirus type 7(Ad7) and evaluate the relevance with the ade-novirus receptor .Methods:Binding peptide against Ad 7 was screened by panning the phage display 12 peptides library .The antibody against the selected peptide was prepared and was used to study the binding to the membrane by immunofluorescence technique .Re-sults:Using Ad7 as the target protein , GTS09 peptide was selected from the phage display 12 peptides library by biopanning .GTS09-phage complex could significantly bind Ad 7, with the affinity constant up to 1.93 ×1010 L/mol;at the same time, immunofluorescence showed that antibody of GTS09 could specifically bind to membrane of 293 cell.Conclusion: Antibody against GTS09 peptide could specifically bind to membrane of 293 cell,which shows that the peptide may presumably have homology with the cell receptors of Ad 7.

Objective Chronic atrial fibrillation (AF) results in dedifferentiation of atrial cardiomyocytes that plays an important role in the perpetuation of AF.In this study,we aimed to investigate the changes of titin and α-smooth muscle actin (α-SMA) after long time of AF reversal.Methods Twenty-four goats were randomized into four groups:(1) sinus rhythm (SR),(2) 3 months AF (3-mo AF),(3) 3 months SR after 3 months AF (3-mo post AF),(4) 6 months SR after 3-mo AF (6-mo post AF),with 6 in each group.By pacing on the anterior bottom of left atria appendage (LAA),we established a goat model of chronic AF.Atria effective refractory period (AERP) was measured with electrophysiological methods.Ultra-structure was studied with echocardiography,light and electron microscopy.Titin and α-SMA protein expressions were determined by Western blot.Results The animals underwent high rate pacing on LAA for a mean of 42.23±21.70 days before presenting AF.Electrophysiological analysis revealed that AERP completely resumed in 3-mo post AF goats.Echocardiography displayed that the size of left atrium resumed almost in 6-mo post AF goats (P＜ 0.01).Pathological and electron microscopic examination revealed the disorder of myofibrils,augmentation of intercellular space,myolysis,accumulation of glycogen,and numerous bigger mitochondria among atrial cardiomyocytes in 3-mo AF goats.They recovered mostly in 6-mo post AF goats.Western blot showed that the band density of titin significantly reduced in 3-mo AF goats compared to SR ones [1826±319 vs 5012±854,P＜0.01].In 3-and 6-mo post AF goats,titin increased gradually and it reversed completely in 6-mo post AF goats (3841±601 and 4523±833 respectively,P ＜ 0.01).Conversely,the band density of α-SMA was significantly higher in 3-mo AF goats (5324±948) than in SR ones (1619± 271,P＜0.01).In 3-and 6-mo post-AF goats,α-SMA decreased gradually,and it recovered mostly in 6mo post AF goats (4437± 792 and 2205±540 respectively,P＜0.01,).Conclusions These data indicate that the reversal of dedifferentiation of atrial cardiomyocyts is a very slow process,and it is definitely essential for normal cardiac function.

We constructed plasmid pMTac to overexpress 3-ketosteroid-Δ1-dehydrogenase (KSDD) in Mycobacterium neoaurum JC-12 for improving androst-1,4-diene-3,17-dione (ADD) production. To construct pMTac, pACE promoter on pMF41 was replaced by tac promoter, and then four recombinants were constructed, which were M. neoaurum JC-12/pMF41-gfp, M. neoaurum JC-12/pMTac-gfp, M. neoaurum JC-12/pMF41-ksdd and M. neoaurum JC-12/pMTac-ksdd. Fluorescence detection results show that much more green fluorescent protein (GFP) was expressed in M. neoaurum JC-12/pMTac-ksdd than M. neoaurum JC-12/pMF41-ksdd. The activity of KSDD was 2.41 U/mg in M. neoaurum JC-12/pMTac-ksdd, 6.53-fold as that of M. neoaurum JC-12 and 4.36-fold as that of M. neoaurum JC-12/pMF41-ksdd. In shake flask fermentation, ADD production of M. neoaurum JC-12/pMTac-ksdd was 5.94 g/L, increased about 22.2% compared to the original strain M. neoaurum JC-12 and 12.7% to M. neoaurum JC-12/pMF41-ksdd. AD (4-androstene-3,17-dione) production of JC-12/pMTac-ksdd was 0.17 g/L, decreased 81.5% compared to M. neoaurum JC-12 and 71.2% to M neoaurum JC-12/pMF41-ksdd. In the 5 L fermenter, 20 g/L phytosterols was used as substrate, ADD production of M. neoaurum JC-12/pMTac-ksdd was improved to 10.28 g/L. pMTac is favorable for expressing KSDD in M. neoaurum JC-12, and overexpression of KSDD has beneficial effect on ADD producing, and it is the highest level ever reported using fermentation method in M. neoaurum.
Androstadienes ; metabolism ; Fermentation ; Industrial Microbiology ; Mycobacterium ; Oxidoreductases ; genetics ; metabolism ; Phytosterols ; metabolism ; Plasmids

Objective To evaluate left ventricular(LV)myocardial contraction patterns and function when pacing in different right ventricular(RV)sites and discuss echocardiogarphic method to evaluate physiologcal pacing mode.Methods This study included 26 patients with paroxysmal supraventricular tachycardia without organic heart disease.Four pacing modes including right atrium pacing(AAI),RV apex pacing(VVI-RVA),RV septal pacing(VVI-IVS)and RV outflow tract pacing(VVI-RVOT)were performed on the patients in a random order after succussful radiofrequency ablation.The parameters measured in each pacing mode included(1)LV systolic function parameters:LV twist angle(Twist),aortic systolic velocity-time integral(VTIAo)and LV global strain(Gε)；(2)LV contracting pattern:segmental peak systolic strain(Sε),the time to peak value(TPε),and the distribution of segmental Sε,TPε in each layer or wall.The relationship between Sε,TPε of each wall was analyzed.[Results]Pacing from RV sites showed lower Twist,VTIAO and Gε than AAI mode.Gε demonstrated significant difference in three RV sites pacing mode(VVI-RVOT＞VVI-IVS＞VVI-RVA,P＜0.05).Compared with the AAI mode,the distribution of segmental Sε,TPε in the each layer or wall alerted significantly in three RV sites pacing mode,especially in VV1-RVA.The distribution pattern was similar in VVI-RVOT and VVI-IVS.Furthermore,the wall Sε collated negtively with wall TPε(r =-0.51,P＜0.001).[Conclusions]Compared with AAI mode,RV pacing,especially the VVI-RVA induced the alternation of LV contraction patterns and reduction of systolic function.Longitudinal strain parameters can be used to assess the myocardial contraction patterns and function in different pacing mode.

Objective:To explore the curative effects and securities of ticagrelor and clopidogrel in the antiplatelet therapy for coronary heart disease in the aged patients, and to provide a more rational strategy for antiplatelet therapy.Methods:Computer search was performed in Cochrane Central Register of Controlled Trial, Ovid-Medline, EMBase, PubMed, CNKI, Wanfang, VIP and CBM, and the randomized controlled trial (RCT) of ticagrelor and clopidogrel in the treatment of coronary heart disease in the old people were collected.The patients in ticagrelor group were given ticagrelor and other drugs, and the patients in clopidogrel group were given clopidogrel and other drugs.RevMan 5.3software was used to perform Meta-analysis, and the adverse events related to the effectiveness such as the major adverse cardiovascular events (MACE) , myocardial infarction (MI) , stent thrombosis, death, stroke and the adverse events related to safety (bleeding event) were observed.Results:According to inclusion and exclusion criteria, a total of 15RCT were included.The results of Meta-analysis showed that the incidences of MACE (RR=0.59, 95％CI:0.46-0.76, Z=4.08, P＜0.01) , MI (RR=0.48, 95％CI:0.28-0.81, Z=2.74, P=0.006) , stent thrombosis (RR=0.16, 95％CI:0.06-0.48, Z=3.30, P=0.0010) , and death (RR=0.52, 95％CI:0.30-0.89, Z=2.41, P=0.02) in ticagrelor group were decreased compared with clopidogrel group;there was no significant difference in stroke rate (RR=0.76, 95％CI:0.39-1.47, Z=0.81, P=0.42) between two groups, and the incidence of bleeding event in ticagrelor group was increased compared with clopidogrel group (RR=1.57, 95％CI:1.20-2.05, Z=3.28, P=0.001) .Conclusion:For the aged patients with coronary heart disease, ticagrelor is superior to clopidogrel;but the incidence of bleeding is increased.

Objective:To investigate the alteration of right ventricular function after catheter ablation in patients with persistent atrial fibrillation(PAF) and concomitant heart failure with preserved ejection fraction (HFpEF).Methods:The prospective observational study was performed in patients with HFpEF-PAF and undergoing first-time radiofrequency ablation procedures in the First Affiliated Hospital of Nanjing University between May to December 2019. Right ventricular functional parameters were measured before and 5 days, 1, 3, 6 and 12 months after the ablation by transthoracic echocardiography, respectively, including the right ventricular fractional area change (RVFAC), tricuspid annular plane systolic excursion(TAPSE), tricuspid annular diameter (TVAD), tricuspid annular peak systolic speed(TDI-S′) and longitudinal strain of right ventricular free wall (RVFLS). Meanwhile, routine ECG and Holter recordings were performed at each follow-up time point.Results:In this study, atrial fibrillation (AF) recurrence occurred in 4 patients at the 3rd month after ablation, and 7 patients failed to follow up due to the Covid-19. Finally, 19 patients were followed up for the evaluation of cardiac function after catheter ablation. Compared with pre-ablation, right ventricular structural and functional paramters(RVFAC, TAPSE, TVAD, TDI-S′, RVFLS) improved significantly at all stages of follow-up( all P<0.05). Patients with atrial fibrillation recurrence had lower RVFLS and TDI-S′ at the baseline( P=0.039, P=0.019). Conclusions:Right ventricular function could improve in HFpEF-PAF patients who maintain sinus rhythm after radiofrequency ablation.

2-Hydroxybutyric acid (2-HBA) is an important intermediate for synthesizing biodegradable materials and various medicines. Chemically synthesized racemized 2-HBA requires deracemization to obtain optically pure enantiomers for industrial application. In this study, we designed a cascade biosynthesis system in Escherichia coli BL21 by coexpressing L-threonine deaminase (TD), NAD-dependent L-lactate dehydrogenase (LDH) and formate dehydrogenase (FDH) for production of optically pure (S)-2-HBA from bulk chemical L-threonine (L-Thr). To coordinate the production rate and the consumption rate of the intermediate 2-oxobutyric acid in the multi-enzyme cascade catalytic reactions, we explored promoter engineering to regulate the expression levels of TD and FDH, and developed a recombinant strain P21285FDH-T7V7827 with a tunable system to achieve a coordinated multi-enzyme expression. The recombinant strain P21285FDH-T7V7827 was able to efficiently produce (S)-2-HBA with the highest titer of 143 g/L and a molar yield of 97% achieved within 16 hours. This titer was approximately 1.83 times than that of the highest yield reported to date, showing great potential for industrial application. Our results indicated that constructing a multi-enzyme-coordinated expression system in a single cell significantly contributed to the biosynthesis of hydroxyl acids.
Escherichia coli/genetics* ; Formate Dehydrogenases ; Hydroxybutyrates ; Threonine Dehydratase

OBJECTIVETo investigate the effect and safety of acupuncture with regulating menstruation to promote pregnancy for diminished ovarian reverse (DOR).

METHODSAccording to prospective case series, 46 patients were observed and finally 40 cases were included. The acupoints were ① Baihui (GV 20), Shenting (GV 24), Guanyuan (CV 4) and bilateral Benshen (GB 13), Huangshu (KI 16), Dahe (KI 12), Luanchao (Extra), Zusanli (ST 36), Sanyinjiao (SP 6), Taixi (KI 3), Taichong (LR 3) and ② bilateral Shenshu (BL 23) and Ciliao (BL 32). The points in the two groups were used alternately. Acupuncture was given for 3 courses, 12 times as a course and 3 times a week. Before and after treatment, and 3 months after treatment, follicle-stimulating hormone (FSH), follicle-stimulating hormone/luteinizing hormone (FSH/LH), estradiol (E), antral follicle count (AFC) and TCM symptom score were observed. The safety was evaluated.

RESULTSCompared with before treatment, the levels of FSH, FSH/LH decreased, and the levels of Eand AFC increased after treatment and at follow-up (all<0.05). And the TCM symptom scores were significantly lower than those before treatment (both<0.05). The rate of pregnancy after treatment was 15% (6/40). There was no infection and organ injury.

CONCLUSIONAcupuncture with regulating menstruation to promote pregnancy can safely improve the ovarian reserve of patients with DOR.