Coronary artery and myocardium lesion comparison post atrioventricular ring radiofrequency catheter ablation with different catheters / 中华心血管病杂志

<p><b>OBJECTIVE</b>To analyze the extent of myocardium and coronary artery lesion post atrioventricular ring radiofrequency catheter ablation with different tip catheters.</p><p><b>METHODS</b>Twenty-one healthy dogs were randomly divided into 64 degrees C/50 W/100 s, 64 degrees C/100 W/100 s, 45 degrees C/45 W/100 s groups and ablated by 4 mm tip catheter, 8 mm tip catheter and irrigated tip catheter respectively. Left atrioventricular ring and right atrioventricular ring ablation were performed in all dogs. After ablation, myocardium lesion volume was calculated as 1/6pi x length x width x depth. Histological examinations were performed at the myocardium tissue at ablation sites.</p><p><b>RESULTS</b>The lesion depths post 8 mm tip catheter ablation (7.18 +/- 1.72) mm and irrigated tip catheter ablation (7.99 +/- 1.77) mm were similar and significantly deeper than that post 4 mm tip catheter ablation (4.54 +/- 1.38) mm, P < 0.01. Similar results were found in terms of lesion volume [(356.76 +/- 94.44) mm(3) post 8 mm tip catheter ablation, (391.69 +/- 109.54) mm(3) post irrigated tip catheter ablation and (191.34 +/- 74.52) mm(3) post 4 mm tip catheter ablation]. Five (5/42, 11.9%) transmural myocardium necrosis and 8 (8/42, 19%) coronary artery lesions were observed post ablations.</p><p><b>CONCLUSION</b>The extents of post ablation myocardium and coronary artery lesion were significantly higher induced by 8 mm tip catheter and irrigate tip catheter compared those by 4 mm tip catheter.</p>

Homocysteine' s effect on tPA and PAI-1 gene expression in HUVEC / 中国应用生理学杂志

<p><b>AIM</b>In order to elucidate the relationship between homocysteine (Hcy) and the fibrinolytic system, we examined the effect of Hcy on tissue- type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) gene expression in human umbilical vein endothelial cells (HUVEC) in vitro.</p><p><b>METHODS</b>Total RNA was extracted from HUVEC exposed to physical and pathological concentrations of Hcy (0, 10, 50, 200, 500 micromol/L ) for 24 hours, using the guanidinium isothiocyanate method. The semi-quantification of tPA and PAI-1 mRNA in HUVEC was carried out by reverse transcriptase-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>PAI-1 mRNA levels was enhanced by Hcy at concentrations of 500 micromol/L of Hcy, compared with that of 0 micromol/L Hcy (P < 0.05). The mRNA expression of tPA, however, was significantly decreased at concentrations of 500 micromol/L Hcy, compared with that of 10 micromol/L Hcy (P < 0.05), but compared with the control group, the tPA level of 10 micromol/L Hcy was much higher (P < 0.05).</p><p><b>CONCLUSION</b>Hyperhomocysteinemia increases the incidence of cardio cerebral vascular disease, which may be caused by decreasing the activity of fibrinolytic system, whereas, the physiological concentration of Hcy may be decreased the incidence by enhancing the activity of fibrinolytic system.</p>