scholarly journals Supraphysiological Testosterone Levels Shorten the QT Interval but do Not Alter Total Anatomic Myocardial Infarct Size in Rabbits with Acute Myocardial Infarction

Author(s):  
Michael J. Herring
1981 ◽  
Author(s):  
K Genth ◽  
J Frank ◽  
J Schaefer ◽  
V Korten ◽  
D Heene

The influence of streptokinase (SK) on myocardial infarct size and left ventricular function after acute myocardial infarction was investigated. 21 patients with myocardial infarction received SK (SK-group), 27 patients underwent conventional therapy (C-group). In both groups therapy started within 8 hours after onset of chest pain. In the SK-group initially 250 000 IU were administered intravenously, followed by a maintenance dose of 100 000 IU/h, lasting 15 hours. Blood samples at 8 hours intervals were collected for 3 days for serial CPK-analysis to calculate infarct size (I=∫f(t)×dt×K×bw). M-mode echocardiography was taken before start of t her a py and after 15, 24, 48 and 72 hours. AOP and heart rate were recorded continuously. Infarct size was 47±12g in the SK-group and 84±25g in the C-group (p<0.05). The average time to peak blood CPK-activity was 24 hours in the SK-group and 40 hours in the C-group. Peak CPK-level was significantly higher (p<0.5) in the SK-group (841±160U/l) than in the C-group (532±13 8 U / l ) . In 16 patients of the SK-group short periods of ventricular tachycardia were recorded during the period of fibrinolysis. Before therapy all patients showed abnormal motion of the posterior left ventricular wall and/or the interventricular septum, detected by echocardiography. 14 patients showed after fibrinolysis an improved or normalized motion.The results indicate that early fibrinolysis may reopen the occluded coronary artery. Reperfusion of the ischemic perfusion area may salvage jeo pardized myocardium, therefore infarct size was reduced and ventricular function improved.


2015 ◽  
Vol 37 (1) ◽  
pp. 162-175 ◽  
Author(s):  
Lichan Tao ◽  
Yihua Bei ◽  
Shenghui Lin ◽  
Haifeng Zhang ◽  
Yanli Zhou ◽  
...  

Background/Aims: Acute myocardial infarction (AMI) represents a major cause of morbidity and mortality worldwide. Exercise has been proved to reduce myocardial ischemia-reperfusion (I/R) injury However it remains unclear whether, and (if so) how, exercise could protect against AMI. Methods: Mice were trained using a 3-week swimming protocol, and then subjected to left coronary artery (LCA) ligation, and finally sacrificed 24 h after AMI. Myocardial infarct size was examined with triphenyltetrazolium chloride staining. Cardiac apoptosis was determined by TUNEL staining. Mitochondria density was checked by Mito-Tracker immunofluorescent staining. Quantitative reverse transcription polymerase chain reactions and Western blotting were used to determine genes related to apoptosis, autophagy and myocardial energy metabolism. Results: Exercise training reduces myocardial infarct size and abolishes AMI-induced autophagy and apoptosis. AMI leads to a shift from fatty acid to glucose metabolism in the myocardium with a downregulation of PPAR-α and PPAR-γ. Also, AMI induces an adaptive increase of mitochondrial DNA replication and transcription in the acute phase of MI, accompanied by an activation of PGC-1α signaling. Exercise abolishes the derangement of myocardial glucose and lipid metabolism and further enhances the adaptive increase of mitochondrial biogenesis. Conclusion: Exercise training protects against AMI-induced acute cardiac injury through improving myocardial energy metabolism and enhancing the early adaptive change of mitochondrial biogenesis.


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