In open-chest dogs, the left anterior descending coronary artery was ligated for 150 min. The heart was semiserially cut on a cryomicrotome and areas of ischemic damage were visualized by means of glycogen depletion (PAS reaction) and tissue acidosis (a "sandwich" technique with pH indicator dispersed in a layer of gel). The extent of myocardial damage was determined morphometrically. The mass of the glycogen-depleted heart muscle was greater than the mass of the ischemic tissue detected by means of decreased pH (p less than 0.01). The border zone was characterized by glycogen depletion without acidosis. Circulation studies using intravital fluorescein staining have shown that perfusion is partially retained in the border zone; it is assumed that the hypoperfusion triggers glycogenolysis. Nevertheless, the level of perfusion suffices to wash out the acidic end products. Comparison of contrapulsation-treated dogs and untreated dogs shows that the amount of damaged tissue comprising the border zone can be reduced by this therapeutic intervention (p less than 0.02) - in contrast to the acidotic tissue, the amount of which is not significantly influenced. Therefore the border zone contains damaged but still viable muscle cells.

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Recent efforts in artificial heart research in Czechoslovakia.

The authors present basic information about the technical development of the total artificial heart (TAH) and TAH drivers. Long-term experiments, in which the TAH TNS-Brno-II and VII and the Rostock hearts were implanted, are described. Long-term experiments were dedicated to analysis of specific pathophysiologic problems (venous hypertension, thrombogenesis, and calcification) in order to increase survival rates. Thrombogenesis has been partially solved in the TNS-BRNO-VII device by optimal TAH construction using an asymmetric driving diaphragm, the undulating motion of which produced excellent results. Two methods for prevention of increase in central venous pressure (CVP) are verified: administration of antihypertensive drugs and atrial electrical stimulation. Of 155 calves studied, 50 long-term experiments in calves and one in a goat were done. The survival of these animals extended from 31 to 293 days of pumping (average survival, 116.9 days). To prevent driving diaphragm calcification, we have incorporated exogenic inhibitors of calcification into the diaphragm biomaterial (polyurethane). A unique long-term experiment with intrathoracic TAH implantation in the goat is also described. In addition clinical use of the TAH as a bridge to transplantation is discussed. Parallel research with the left ventricular assist device (LVAD) system was studied experimentally, and twice used in patients. The TAH TNS-BRNO-VII/80/clin/ was used in four patients. It worked faultlessly for 22 hours to 10 days. More precise and specific indications for TAH implantation when used as a bridge to transplantation are needed.

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PubMedDate not supplied

Calciphylaxis and cerebral atrophy in man.

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Aged↗

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Some problems associated with the implantation of a cardiac prosthesis and with early postoperative care in animals with a total artificial heart.

The progress in the methods and techniques for surgical implantation of the TAH has progressed in parallel with the technology and design of the cardiac prosthesis. During the period from December 1974 to May 1982 the authors performed altogether 75 orthotopic implantations of eight types of TAH in calves. The Soviet TAH type KEDR I-III was implanted in 26 calves, type MODUL to one calf. The American TAH JARVIK 3 was implanted in one calf and Czechoslovak TAH type TNS BRNO I-III in 47 calves. The modification of blood pump and improved system of its control provided for the limitation of the range of surgery and to shorten the time of operation and cardiopulmonary bypass. The methods of preoperative care, anaesthesia, cardiopulmonary bypass and postoperative care in our laboratory were gradually improving in parallel. This was associated with maximum survival time of animals in the course of the research period which gradually increased from 5.5 h in 1974 to 173 days in 1982. The chief experiences acquired from all experiments performed are presented and problems associated with the investigation of the TAH in general are discussed in this paper.

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