Objective To investigate the effect of 2-methoxyestradiol(2ME2)on the expressions of hypoxia-inducible factor 1α and apoptosis-related genes(RTP801 and caspase-3)in the hippocampus of rats following global cerebral ischemia.Methods A total of 168 adult male SD rats were randomized into 2 groups,global cerebral isehemia group(GI group,n=84)and global cerebral ischemia+2ME2 treatment group(GI+2ME2 group,n=84).In GI and GI+2ME2 groups,4 vessel occlusion(4-vo)global ischemia was induced,and the rats were sacrificed at 6,12,24,48,96h,and 5 and 7 days after the reperfusion.Nissl staining was used for quantitative analysis of the hippocampal neurons,and immunohistochemistry and RT-PCR were performed to detect the expressions of HIF-1α protein,caspase-3 protein and RTP801 mRNA.Results At 48,96h and 5 and 7 days after the reperfusion,the numbers of hippocampal neurons in GI+2ME2 group were 37.09±3.52,26.93±3.10,22.22±3.091,and 6.98±3.07,respectively,significantly higher than those in GI group(P＜0.05).2ME2 significantly suppressed the expression levels of HIF-1α and reduced the numbers of the cells positive for HIF-1α protein to 1 1.47±1.9,20.27±2.07,3.12±0.89,1.07±0.83 at these time points(P＜0.05).The expressions of caspase-3 protein were decreased significantly in GI+2ME2 group,with the numbers of positive cells of 12.39±1.67,20.65±2.01,15.61±1.26,and 6.57±1.12 at the time points.The absorbance of RTP801 mRNA expression at the time points from 12 h to 5 days in GI+2ME2 group was 0.750±0.078,1.008±0.090,0.717±0.072,0.43 1±0.047,and 0.23 1±0.028,respectively,significantly lower than that in GI group(P＜0.05).Conclusion 2ME2 offers brain protection in rats with global cerebral ischemia and suppresses the elevation in the expressions of hypoxia-inducible factor 1α,RTP801 and caspase-3.

BACKGROUNDRadiofrequency (RF) ablation has become a widely accepted treatment for atrial fibrillation (AF). This study aimed to identify the efficacy and safety of pulmonary vein (PV) ablation with ethanol and to explore an alternative energy source for catheter ablation of AF.

METHODSTwelve open-chest mongrel dogs were randomized into ethanol ablation group and control group. Both the injections and electrophysiological mapping procedures were performed epicardialy. In ethanol ablation group (n = 6), injections were performed to circumferentially ablate the root of each PV (0.2 ml each site, 3 mm apart) with 95% ethanol using an 1 ml injector. In control group (n = 6), saline was injected other than ethanol. PV isolation was confirmed with a circular catheter immediately after the procedure and at follow up of 30 days. PV isolation was defined as the absence of PV potentials at each electrode of the circular catheter positioned at the PV side of the lesions, as well as complete conduction block into left atrium (LA) during PV pacing.

RESULTSPV electrical isolation with complete bidirectional conduction block was achieved with ethanol immediately and at 30 days in 95% of PVs, while saline injection caused only transient conduction changes between LA and PVs. In ethanol group, histologic analysis showed transmural lesions at 30 days. And there was no evidence of PV stenosis or thrombus formation. Mean LA diameter was not significantly different between baseline and 30 days.

CONCLUSIONEthanol is a safe energy source to effectively isolate PV in canine model and may be promising in endocardial ablation procedure of AF patients in the future.

Animals ; Catheter Ablation ; methods ; Dogs ; Electrophysiology ; Ethanol ; Pulmonary Veins ; physiology ; surgery ; Random Allocation

OBJECTIVE: To investigate the biological function of Cysteine rich (CysR) domain of a disintegrin and metalloprotease with thrombospondin type 1 repeats-13 (ADAMTS13) on cleavage of von Willebrand factor (vWF) and provide experimental evidence for exploring the pathogenesis of thrombotic thrombocytopenic purpura (TTP). METHODS: The six amino acids (EDGTLS) in ADAMTS13 CysR domain were point mutated one by one, and the mutant ADAMTS13 proteins were expressed and purified. The cleavage products of vWF polymer by wild-type or mutant ADAMTS13 under denaturing condition or shear stress were separated by 1% SeaKem HGT agarose gel and detected by Western blot. RESULTS: The mutant ADAMTS13 plasmids (M1: Glu515Ala; M2: Asp516Ala; M3: Gly517Ala; M4: Thr518Ala; M5: Leu519Ala; M6: Ser520Ala) were successfully constructed and the proteins of wild-type and mutant ADAMTS13 were purified. Wild-type ADAMTS13 almost completely cleaved the vWF polymer under denaturing condition, while the cleavage activity of M1 mutant was significantly reduced in the same condition (P<0.01). The cleavage activity of M1 mutant of ADAMTS13 was also significantly reduced compared with that of the wild-type under shear stress (P<0.01). The activity of M1 mutant to cleave the FRETS-vWF73 was dramatically reduced compared with that of wild-type ADAMTS13. However, the binding ability of M1 mutant to vWF was similar with that of wild-type ADAMTS13. CONCLUSION The CysR domain of ADAMTS13 plays an important role in the digestion of vWF under denaturing condition and shear stress. The Glu515 amino acid residue might be an important site for substrate recognition.
ADAM Proteins ; ADAMTS13 Protein/genetics* ; Humans ; Purpura, Thrombotic Thrombocytopenic/genetics* ; von Willebrand Factor/genetics*