Proposed mechanism(s) of transitory ischemic injury to myocardium
The main objective of this study was to produce primary acute ischemic injury to myocardium in a live animal. In vitro, guinea pig platelets were sensitive to perturbation and aggregation by a suspension of ultrafine fibrillary collagen material isolated from the aorta of an aged burro (Equus asinus). The platelets responded to this material down to 100 to 200 ng (dry weight) added to 0.45 ml of platelet-rich plasma, as determined by aggregometric technique. Aortic fibrillary collagen material injected IV into guinea pigs circulating platelets within 5 minutes. In blood samples taken 2.5 hours after injection, 50 to 75% of control levels of platelets were found. In other experiments, 3 anesthetized animals were injected by jugular vein with active fibrillary collagen material. Two control animals were injected with the same dose of the material that had been inactivated (15 minutes at 100 C). Intraventricular pressures and electrocardiographs (ECG) were monitored continuously for the first 30 minutes. The injection of the active fibrillary collagen material caused a large ventricular pressure elevation in approximately 40 s. Within 60 s, there was a reduction in the absolute platelet number in the peripheral circulation. The elevation of ventricular pressure persisted for approximately 5 minutes and was followed within 30 minutes by a set of ECG events suggestive of acute myocardial ischemic injury. The ECG changes seemed to be subsequent to platelet microthrombus formation in the pulmonary arterial microcirculation. By 2.5 hours after the treatment, platelets rebounded into the circulation in 2 surviving guinea pigs, and left ventricular pressures and ECG profiles returned to the preinfusion base lines. Guinea pigs IV infused with similar amounts of inactivated fibrillary collagen material did not show changes.
- Research Organization:
- Comparative Animal Research Lab., Oak Ridge, TN
- OSTI ID:
- 5789549
- Journal Information:
- Am. J. Vet. Res.; (United States), Vol. 40:2
- Country of Publication:
- United States
- Language:
- English
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BURROS
COLLAGEN
ELECTROCARDIOGRAMS
GUINEA PIGS
TIME DEPENDENCE
ANEMIAS
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BIOLOGICAL MATERIALS
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CARDIOVASCULAR SYSTEM
DIAGRAMS
DISEASES
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551000* - Physiological Systems
550200 - Biochemistry