ABSTRACT
Objective To investigate the left ventricular synchrony under different ischemic statuses using phase analysis of 99Tem-MIBI gated SPECT MPI (GSMPI).Methods The data of 129 patients (65 males,64 females,age:48-88 (68.6±10.2) years) who underwent 2-d stress-rest GSMPI were retrospectively analyzed.Perfusion images were scored by a 5-grade criteria (0-4) based on 17 coronary artery segments.Patients were divided into normal perfusion group (G1) and abnormal perfusion group (G2) according to the summed stress scores.G2 was divided into reversible perfusion defect subgroup (G2a) and irreversible perfusion defect subgroup (G2b) by the summed difference scores.The difference of PSD and PHB between groups and the difference between stress and rest GSMPI within each subgroup were compared using two-sample t test and paired t test,respectively.Results The numbers of patients in G1,G2,G2a and G2b were 66,63,39 and 24,respectively.The PSD (18.3±7.8) and PHB (68.6±30.9) of G2 were significantly higher than those (14.3±6.6 and 50.2±20.0) of G1 (t =-3.110,-3.989,both P＜0.05).The PSD and PHB of G2b were higher than those of G2a,but the difference was not statistically significant (t:-1.554 to-0.408,all P＞0.05),and the differences of PSD and PHB between rest and stress MPI within each subgroup were not significantly different (t:-0.961 to-0.114,all P＞0.05).The PSD (20.4±8.1 and 20.8±6.4) and PHB (77.8±53.5 and 78.4±26.7) of rest and stress GSMPI in patients with LVEF ≤60％were significantly higher than those in patients with LVEF＞60％(15.0±6.8 and 15.3±7.0,53.5±23.0 and 55.9±24.5;t:3.642 to 4.567,all P＜0.05).Conclusions 99Tcm-MIBI GSMPI phase analysis can show damage effect of abnormal myocardial perfusion on left ventricular synchrony,which influencing global left ventricular function,and it can show different left ventricular synchrony due to different degrees of myocardial ischemia.There is nearly same value of stress GSMPI and rest GSMPI in assessment of left ventricular synchrony.
ABSTRACT
Objective To evaluate the effect of aminoguanidine on cell apoptosis induced by acute myocardial ischemia in rats.Methods Thirty adult male Sprague-Dawley rats,weighing 250-290 g,were randomly divided into 3 groups (n =10 each):sham operation group (group S),myocardial ischemia group (group Ⅰ),and aminoguanidine group (group AG).The model of acute myocardial ischemia was established by ligating the left anterior descending branch of the coronary artery of rats anesthetized with chloral hydrate.Aminoguanidine 100 mg/kg was intraperitoneally administrated at 6 h of ischemia in AG group,while the equal volume of normal saline was given instead of aminoguanidine in group Ⅰ.The chest was opened at 3 h after aminoguanidine administration and hearts were quickly removed for detection of apoptosis in cardiomyocytes (by TUNEL) and expression of Bcl-2 and Bax in cardiomyocytes (by immuno-histochemistry),and for microscopic examination with light microscope.Apoptotic rate was calculated.Results Compared with group S,the apoptotic rate was significantly increased,the expression of Bax was up-regulated,and the expression of Bcl-2 was downregulated and the ratio of Bcl-2/Bax was decreased in group Ⅰ.Compared with group Ⅰ,the apoptotic rate was significantly decreased,the expression of Bax was down-regulated,and the expression of Bcl-2 was up-regulated,and the ratio of Bcl-2/Bax was increased in group AG.The pathological changes of myocardial cells were significantly attenuated in AG group as compared with group Ⅰ.Conclusion Amionguanidine can inhibit apoptosis in cardiomyocytes and is helpful in mitigating injury induced by acute myocardial ischemia in rats.