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Objective To observe short-term rapid atrial electrical activation on atrial size and atrial systolic function. Methods Twelve anesthetized mongrel dogs were underwent insertion of a transvenous lead at the right atrial appendage and subjected to 5 hours of rapid right atrial pacing at 450 beat/min. Acoustic quantification(AQ) waveform on biatrial was recorded before and after 5 hours pacing with AQ technique. All measurements were made in sinus rhythm. Results After 5 hours rapid right atrial pacing, end systolic volume(ESV) of both left and right atrial enlarged significantly from ( 5.92 ? 1.51 )ml to ( 7.27 ? 1.86 )ml,from ( 3.13? 0.71 )ml to ( 3.58 ? 0.73 )ml, respectively; but biatrial function decreased markedly,left and right atrial ejection fraction decreased from ( 51.03 ? 9.45 ) to ( 38.23 ? 10.52 ),from ( 36.76 ? 5.36 ) to ( 30.71 ? 7.97 ), respectively. However, left atrial ESV enlarged more than right atrial (by 23 vs 8,P
RESUMEN
AIM: To study the apoptotic role of wild-type p53 in induction of plaque instability in atherosclerotic rabbits. METHODS: Fifty-four New Zealand White rabbits underwent balloon-induced abdominal aortic wall injury and then were fed on a diet of 1% cholesterol. At the end of the eighth week, the rabbits were randomly divided into two groups: group A and group B. Recombinant adenovirus carrying p53 and ?-galactosidase (LacZ) genes were injected in group A and B, respectively. Two weeks later, 10 rabbits each in group A and B was killed and the remaining rabbits all underwent pharmacological triggering with injection of Chinese Russell's viper venom and histamine. RESULTS: Compared with group B, p53 gene over-expression in group A resulted in a marked increase in number of positive apoptotic cells (2.5%?0.8% vs 1.0%?0.3%, P