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 describe the new cognition of mapping, ablation and mechanism of typical atrial flutter using non-contact mapping system. Methods In 9 patients with typital AFL, the bi-directional conduction properties of isthmus, atrial activation sequence and reentrant circuit of AFL were mapped using the non-contact mapping system. Linear isthmus radiofrequency ablation was guided by navigation system without fluoroscopy, and isthmus bi-directional block was verified. Results A clockwise moving reentrant activation wavefront in 1 of the 9 patients was observed and a counter-clockwise rotating wavefront in 7 of the 9 patients, respectively. AFL was not inducible in one patient. The mean cycle length of AFL was (215?36) ms. The whole reentrant way and its relation with anatomical structure of right atrium (RA) were displayed by non-contact mapping. In each mapped AFL, the wavefront conducted through the crista terminalis (CT) and propagated slowly, which that indicated the smooth part of RA was involved in the reentrant circuit. In patients with recurrences, the gap in the line of block in the isthmus was identified and ablated, which was navigated by the system. Complete isthmus bi-directional conduction block was achieved at the end of the procedure except in two patients. No recurrences of AFL occurred during the follow-up of 12-36 months. Conclusion The whole activation circuit and its relation with RA anatomical structure of typical AFL can be directly visualized and its reentry mechanism was verified by non-contact mapping system. In recurred cases ,the gap of isthmus block was identified and ablated accurately. CT, which was previously supposed to be a complete posterior conduction barrier, was now proved to be of transverse slow conduction by non-contact mapping.

Objective To evaluate the effect of radiofrequency catheter ablation treament of supraventricular tachyarrhythmias on spontaneous attack of atrial fibrillation (AF) and to further discuss the electrophysiological mechanisms of AF. Methods Thirty-one patients (20 men, 11 women; mean age 54?12 years, age range 24-69 years) with supraventricular tachyarrhythmias coexisting with AF were included in the study. The mean history of the study group was 9?5 (range 1-19) years and the mean number of AF attack was 6?5 times (range 2-18). Of the 31 cases, 5 supraventricular tachyarrhythmias were electrophysiologically proven to be typical atrial flutter (AFL), 17 atrioventricular reentrant tachycardia (AVRT), 9 atrioventricular nodal reentrant tachycardia (AVNRT). Linear lesions to make bi-directional block were done in cavo-tricuspid isthmus in AFL patients, slow pathway modification in AVNRT and accessory pathway ablation in AVRT. Results After mean follow-up of 39?19 months (range 12-72), of the 31 patients, 23 had no occurrence of AF. In 3 of the 5 AFL patients, no AF occurred after ablation, but 2 still had AF occurrence, of whom one had frequent atrial premature contractions (APCs) and short runs of AF. In 26 patients with supraventricular tachycardia, 20 had no occurrence of AF after ablation. In the remaining 6, 2 had less frequent occurrence, and 4 remained the same, of whom one had hypertention with enlarged left atrium, and another had frequent APCs and short runs of atrial tachycardia. Conclusion AFL may share the same substrate with AF or may be the trigger factor of AF, and AVNRT and AVRT are only trigger factors of AF. So after successful ablation treatment of these tachycardias, no AF occurs. But in some cases, AF substrate still exists, and AF can be triggered by other trigger factors besides tachycardias mentioned above.

Dominant intercropping combination between biennial Ophiopogon joponicvs and different crops was tried with reference to agricultural condition specific to Cixi county,zhejiang Province. The quantity and quality of the product and its economical effect resulted in biennal cultivation with different crop: were assessed. Results showed that the optimurm combination in the first year of undersowing was cotton in the summer and broadbean(vicia faba L. ) in the winter, while in the second year watctmelon (Citrullus lanatus) was the ideal combination in he summer.

Objective To observe the alteration of heart rate turbulence(HRT) before and after left atrium circumferential ablation surrounding pulmonary veins(LACA) in patients with paroxysmal atrial fibrillation(PAF) in order to determine whether concealed vagal denervation occurred during the procedure.Methods Forty-four patients(26 male,aged 53?11 years) with paroxysmal atrial fibrillation who had received catheter ablation treatment from Mar 2006 to Dec 2006 were included in the study.The mean diameter of left atrium was 36?5 cm and the mean ejection fracion was 0.65?0.04 in these patients.The left atrium circumferential ablation surrounding pulmonary veins were performed in all the patients to achieve complete electrical isolation of both ipsilateral pulmonary veins.RS2 extrastimulus were delivered from right ventricular apex to obtain heart rate turbulence with 60% of basic sinus cycle length and at twice diastolic threshold before and after the procedure.Turbulence onset(TO)(%) and turbulence slope(TS)(msec/beat) were obtained using average five respective ventricular premature beats.Thirty-seven patients who had received catheter ablation of supraventricular tachycardia were included as control.Results There was no significant difference between AF and control group in HRT [TO:-0.021 6%?0.023 6% vs-0.023 6%?0.018 5%(P=0.67);TS: 7.331 8?6.983 5 vs 9.667 9?6.065 2(P=0.12)].TO and TS changed significantly after LACA [-0.021 6?0.023 6 to 0.000 9?0.013 3(P

Objective Previous investigations have shown that N-aeetylcysteine (NAC) could regulate diverse cell type's apoptosis. The purpose of this study was to evaluate the mechanism of NAC reversed apoptosis ofcardiomyocytes induced by hypoxia-reoxygenation (H/R). Methods Cardiomyocytes were treated with hypoxia 6 h and reoxygenation 72 h in the absence and presence of NAC (100 μmol/ L). The ROS was assayed by using Image-iTTM LIVE green reactive oxygen species detection kit. The viability of cell was assayed with trypan blue. Early stages ofapoptosis were assessed by flow cytometry using Annexin V, and late stages ofapoptosis were assessed using TUNEL system. Bcl2 and bax mRNA levels were determincd by real-time quantitative PCR. Bcl2, bax, p38 and pp38 protein levels were determined by western blot. Results We found that H/R could markedly increase ROS generation and induce the apoptosis of cardiomyocytes (P<0.01). NAC (100 p tool/L) significantly reduced the generation of ROS and apoptosis (P all <0.01). NAC also significantly reduced the protein ratio of pp38 and p38 and increased the RNA and protein ratio of bcl2 and bax (P all <0.01). Conclusion The results showed that NAC significantly reduced apoptosis through inhibiting the phosphorylation of p38 signal pathway, which has potential value for clinical cardiac diseases.

Objective To investigate the effects of normal caloric high-protein diet on metabolic parameters and gastrointestinal hormones in patients with obesity or type 2 diabetes mellitus (T2DM).Methods Totally 30 obese subjects (OB group) and 40 obese patients with type 2 diabetes mellitus (T2DM group) received normal caloric high-protein diet for 24 weeks.Then body weight,fat mass,and metabolic parameters were assessed.The serum ghrelin and glucagon-like peptide-1 (GLP-1) levels were also measured at 0 and 2 h after an oral 100 g of steamed bread meal test.Results After 24 weeks,body weight [(78.23 ± 7.51) kg vs (80.83±8.13) kg,P=0.016; (80.45±7.48) kg vs (83.26±9.35) kg,P=0.011],body mass index [(31.03 ±2.72) kg/m2 vs (32.01 ±2.95) kg/m2,P=0.033; (32.63 ±2.81) kg/m2 vs (33.86±3.03) kg/m2,P =0.043],waist circumference [(93.65 ± 6.23) cm vs (97.30 ± 7.81) cm,P =0.041 ;(97.02±7.43) cm vs (101.87 ±9.87) cm,P =0.034],fat mass [(30.42 ±6.18) kg vs (32.47 ±5.91) kg,P=0.022; (34.23 ±7.03) kg vs (36.64 ±6.83) kg,P =0.032],fasting serum insulin [(10.81±3.69) mmol/Lvs (13.58±4.86) mmol/L,P=0.012; (9.58±3.51) mmol/Lvs (10.82±4.28) mmol/L,P =0.015],HOMA-insulin resistance index [(2.42 ± 0.83) vs (3.16 ± 1.21),P =0.019; (3.15±0.74) vs (4.13±0.67),P=0.024] and triglycerides [(1.24±0.32) mmol/Lvs (1.49±0.52) mmol/L,P=0.046; (1.86±1.05) mmol/L vs (2.46±1.85) mmol/L,P=0.034] were significantly decreased in OB and T2DM groups,respectively,compared with 0 week.Fasting blood glucose (FBG)and glycosylated hemoglobin were also significantly declined in T2DM group [FBG:(6.73 ± 1.25) mmol/Lv s (8.63 ±2.81)) mmol/L,P=0.010; HbA1c (6.44 ±0.47) vs (7.38 ±0.33),P=0.031].The serum ghrelin and GLP-1 both increased at 0h and 2 h after meal test in OB and T2DM groups [fasting serum ghrelin:(4.98 ±0.89) μg/L vs (3.95 ±0.98) μg/L,P=0.021; (4.23 ± 1.67) μg/L vs (3.15 ± 1.01) μgL,P=0.025; 2 h postprandial serum ghrelin:(2.98 ±0.96) μg/L vs (2.56 ±0.83) μg/L,P =0.046; (2.83 ± 1.03) μg/L vs (1.95 ±0.92) μg/L,P =0.033; fasting serum GLP-1:(6.06 ±0.63) μg/L vs (5.13±0.59) μg/L,P=0.041; (5.23±0.71) μg/Lv s (4.49±0.53) μg/L,P=0.039; 2 h postprandialserum GLP-1:(10.01±1.01) μg/L vs (7.68±0.94) μg/L,P=0.007; (8.87±0.94) μg/Lvs (6.59 ± 0.87) μg/L,P =0.013].Conclusions Normal caloric high-protein diet can reduce body weight and serum glucose.Those effects may be due to the increase in secretion of GLP-1.

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.

Objective To study the mode and clinical implications of onset of spontaneous tosade de pointes in the congenital long QT syndrome. Methods We reviewed electrocardiograms (ECGs) of 55 patients with congenital QT syndrome for syncope. Documentation of the onset of tosade de pointes was available for 16 patients. All these patients had "definitive long QT syndrome" by accepted clinical and ECG criteria. Results One hundren and forty-nine runs of tosade de pointes were documented in 16 patients,of whom,there were 130 runs of pause-dependent tosade de pointes. Conclusion Our results show that the pause-dependent tosade de pointes,which has been recognized as a hallmark of tosade de pointes in the acquired long QT syndrome,plays a major role in the genesis of tosade de pointes in the congenital long QT syndrome.

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