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At least 19 recordsLinked to original sources

Donor-circulation as cardiopulmonary bypass in experimental heart transplantation.

Heart transplantation was performed on 21 mongrel dogs using donor-circulation of another, bigger dog, instead of the heart-lung machine. All the dogs survived the operation. They showed a moderate metabolic acidosis, which was more related to a reduced blood flow of the recipient than to inadequate oxygenation capacity of the pump dog during transplantation, and which was corrected by administration of bicarbonate after the procedure. The technique was superior to disposable oxygenators in reducing the expense of the operation and providing a more gentle perfusion.

Acid-Base Equilibrium

[Lymphocyte reactions at early periods after heart transplantation].

The authors determined the quantitative and qualitative composition of the white blood and dehydrogenase activity of lymphocytes in the blood from the afferent and afferent vessels of the transplanted heart at the early postoperative periods in dogs. There was noted a reduction of the lymphocyte count in the blood flowing from the transplanted heart on account of retention of these cells in the transplant, and also an inversion of the mitochondrial dehydrogenases activity due to the lymphocyte contact with foreign antigens of the transplanted heart. A hypothesis is put forward that the inversion mechanism was connected with the lymphocyte functions in the capacity of immunocompetent cells.

Animals

Functional independence of donor and recipient cardiac tissues of single and double heart transplant patients revealed by chronobiology.

3 total (single) and 1 double-heart-transplant patients were studied for temporal changes in the electrical events of cardiac function. Results of statistical analyses document the existence of circadian rhythms in the donor and recipient P--P or R--R intervals. However, for 1 total-heart-transplant patient studied at intervals during the year following implant and the double-heart-transplant patient 5 mth after surgery, the period (tau) of the rhythm in the P--P or R--R interval of the recipient tissue deviated greatly from that of 24.0 h. For the total-heart-transplant patient studied 1 mth prior to death, the tau was 32.3 h; for the double-heart-transplant patient, the tau was 29.0 h. In both patients, the donor heart tissue continued to exhibit a 24-h rhythm. These findings imply that changes in tau for the rhythm in P--P or R--R interval may reflect aspects of disrupted physiologic, feedback, regulatory mechanisms or perhaps graft rejection. Although additional study is required, the possibility that alteration in tau is associated with rejection is intriguing since if documented, then the noninvasive monitoring of ECG and subsequent analysis of data for significant deviations of tau from 24.0 h will be useful as an additional tool for monitoring host tolerance for the heart implant.

Bed Rest

The effect of digoxin on the contractility of transplanted heart.

The effects of digoxin on the contractility of orthotopically transplanted heart was studied in dogs. Intravenously administered digoxin produced a fall in the rate and output of the transplanted heart without any change in stroke volume, whereas the output of the intact heart was slightly improved due to a small increase of stroke volume. This difference was thought to be due to the action of digitalis which is mediated via the nervous pathways, which are interrupted in the transplanted heart.

Animals

Human heart transplantation: current status.

The overall survival rate for 97 heart transplant recipients operated on from 1968 to 1975 has been 49% at one year and 23% at five years. Progressive improvement in one-year survival has been achieved, from 22% in 1968 to 62% in 1974. The major factors responsible for increasing survival are better understanding and management of acute and chronic rejection. Current results suggest that heart transplantation deserves wider application in the treatment of selected patients with end-stage myocardial insufficiency.

Acute Disease

[Intrathoracic parallel heart transplantation in the dog].

The authors report on intrathoracic parallel heart transplantation which was experimentally tried on 10 mongrel dogs. The described technique is advantageous since it can be performed without extracorporeal circulation. The results of hemodynamic studies on graft and recipient heart vindicate further employment of this technique to study several problems of heart transplantation still unsolved.

Animals

Heart transplantation in endotoxin shock.

The condition of the heart from dogs in endotoxin shock was evaluated, and all dogs in the control group receiving 5 milligrams per kilogram to Eschericia coli endotoxin died within two to 14 hours. Hearts from four other dogs receiving the same dosage of endotoxin were allografted orthotopically into healthy recipient dogs. The donor heart was taken in the terminal phase of shock, after the blood pressure of the donor had declined to 50 millimeters of mercury or less. All four heart allografts functioned normally in the healthy hosts, demonstrating that lethal levels of gram-negative endotoxin do not produce direct irreversible damage to the myocardium or to the conduction mechanism of the heart. This also was shown in one pair of monkeys; the donor monkey had received ten times the dosage of endotoxin used in the dogs. This heart transplant model offers considerable advantage in functional studies of the heart after irreversible shock.

Animals

Active enhancement of heart transplants in the inbred rat with donor strain blood.

Prolongation of survival time of heart transplants in inbred rats following intravenous injection of donor strain blood according to various time-dose schedules is described. The immunological status of long-term survivors shows detectable antidonor antibodies, normal graft-versus-host reactions and rejection of skin grafts in the usual time. Lymphocytotoxic activity is well related to the survival time of the heart in those rats which respond to the treatment.

Animals

Lymphocyte tissue culture studies on human heart transplant recipients. III. Prediction of outcome of transplantation based on immunologic studies.

Using in vitro lymphocyte tissue culture screening tests human heart transplant recipients during the academic year 1973/1974 were evaluated and an attempt made to predict their post-operative rejection course. The tests involved screening for serum depressive factors and screening for the recipient's lymphocyte reactivity. A scoring system was devised whereby the laboratory results could be converted to a predicted rejection score. Of the nine patients studied, eight are still doing well. Three recipient's who had a high postoperative rejection score as determined by an independent clinical team, were correctly identified pre-operatively and one of them had to be retransplanted. These screening tests may be helpful in the future in the selection of recipients.

Cells, Cultured