Biomedical subjects
Publications and source records attributed to K Sedlarik.
Coronary thrombosis is a perilous disease. Animal experiments may contribute to investigate its pathogenesis and treatment. The development of an experimental model of coronary thrombosis on closed thorax is important. In this report the methodics of such model is entered into, pointing at its dangers and possible complications.
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Surgery on coronary vessels requires high surgical skill. For this reason generally, operations on experimental animals are carried out for exercise. These operative interventions require an extensive display of technique and personnel. A phantom, i.e. an arrested perfused porcine heart, was used to exercise the surgical technique. Material and personnel could be spared by this way, and a great number of exercising operations was performed. The phantom is described and its efficiency discussed.
The increasing frequency of cardiac infarction and its close correlation with coronary thrombosis urge to seek for new therapeutic approaches to coronary thrombosis. Proper models are necessary for that. The principles hitherto published are reported as well as the limits of their reliability, and the demanded criteria of a pattern of coronary thrombosis are demonstrated.
Coronary thrombosis was induced in 14 miniature pigs by means of direct current. The induction electrode was introduced via the common carotid artery into the coronary artery. The intensity of current (1 mA) and the duration of current flow (60 min) were kept constant in all the experimental animals. 6 miniature pigs survived the period of observation (48 h). In all instances, an injury to the intima was the morphopathological location factor. With the exception of one animal, which died after an induction time of 60 min, coronary thrombosis was stated in all the miniature pigs. The experimental arrangement which produces closed-thorax coronary thrombosis is suited for cardiosurgical, physiopathological and pharmacological experiments, especially because the anatomy and the degree of development of the porcine heart are most similar to those of the human heart.
By means of electric induction without opening the chest in 23 dogs coronary thromboses were produced with the aid of a standardized method based on a test model of Salazar (1961). The morphological results are reported. 13 of the dogs showed coronary thromboses. At the same time in 12 animals a myocardial infarction could be registered. Altogether, we observed 17 myocardial infarctions. The electric field led to differently severe lesions in the walls of the coronary arteries. The significance of this test model is discussed.
With the aid of a standardized method basing on a report of Salazar (1961) coronary thromboses in pigs were produced by means of electric induction without opening the chest. 12 of 13 pigs showed thromboses in coronary arteries, in 8 animals with embolization of the thrombotic material. At the sametime in 8 pigs a myocardial infarction could be registered. The significance of these experiments discussed.
The thrombolytic action of the streptokinase preparation Awelysin was investigated in animal experiments. After evaluation of the optimum fibrinolytically effective streptokinase dose and the changes in the clotting system induced by intravenous application of streptokinase experimentally produced deposition thrombi and clotting thrombi were lysed intravascularly in dogs, rabbits and rats. The success of the therapy was confirmed angiographically or rheographically.
The authors report on an experimental model of coronary thrombosis, electrically induced in the closed thorax. By this technique they succeeded inducing coronary thrombosis with myocardial infarction in 13 cases out of 21. In three cases just disseminated myocardial necrosis was proved. All of the other animals showed vast myocardial infarctions. Coronarography, arterial pressures, typical shifts of serum enzymes, decrease of thrombocytes and fibrinogen and elevation of spontaneous fibrinolysis during the first hours proved to be valuable for the confirmation of successful inducing of thrombosis; in individual cases, however, these estimations yield no absolute certainty.
A method for inducing peripheric white thrombosis in the dog is described. Thrombogenesis was initiated by continuous current 10 mA for 15 minutes. In each case the intravascular electrode was inserted in the femoral artery, the intima lying close to the electrode. Electromagnetic flow measurements and angiography proved the thrombosis.
The problems of substituting larger areas of the bladder wall are not definitely solved. Experiments on implantation of auto-allografts resulted in complications, which prevented correct epithelization of the interior surface, due to ischemia. In successful experiments on 34 rabbits, the authors obtained sufficient blood supply of the implantate and re-epithelization of the graft's interior surface in a two-stage operation.
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