Microemulsified dihydroheptaprenol (DHP) was administered intramuscularly to clinically healthy calves at doses of 4, 6 and 8 mg/kg body weight. Marked increase of neutrophil counts was observed 0.5, 1 and 2 days after the injection at a dose of 6 mg/kg. Nitroblue tetrazolium reducing activity of neutrophils was also obviously enhanced 1, 2 and 3 days after DHP administration. Phagocytic killing of Staphylococcus aureus by neutrophils was further enhanced markedly 1, 2 and 3 days after the drug injection at 6 mg/kg.

Animals↗

PubMedDate not supplied

Combined use of surface and perfusion hypothermia in intracardiac surgery in infants under one year of age.

Deep hypothermia has recently gained popularity as an adjunct to intracardiac surgery for neonates and infants. A number of Japanese investigators played a role in the development and clinical application of both simple surface-induced hypothermia and the combined use of surface and perfusion cooling. The developmental history of both methods is described in detail. At the Heart Institute of Japan, 71 infants under one year of age underwent intracardiac surgery over the past six years. There has been a notable decrease in operative mortality since the employment of circulatory arrest under deep hypothermia and limited pump-perfusion. This trend is marked in infants with ventricular septal defect and pulmonary hypertension, and in those with total anomalous pulmonary venous connection. The Landé-Edwards membrane oxygenator proved helpful in prevention of postoperative pulmonary complications.

Age Factors↗

PubMedDate not supplied

Electrophysiologic assessment of the transplanted canine heart: correspondence to histopathologic findings in acute rejection.

This study was undertaken to electrophysiologically find signs of rejection after heart transplantation. A donor heart with a created atrial septal defect was implanted in the retroperitoneal space by anastomosing the thoracic aorta and left pulmonary artery of the donor heart to the abdominal aorta and inferior vena cava of the recipient heart, respectively. Endocardial leads were set up in the right atrium in the vicinity of the bundle of His and in the right ventricle. Cyclosporine (10 to 18 mg/kg/day, continuously) and prednisolone (1.0 mg/kg/day, for the first 4 days) were given orally. Electrophysiologic examinations were performed 1 to 4 days (control data) after the transplantation and were compared with data obtained 5 to 21 days after operation on 12 mongrel dogs. Finally, histopathology of the donor heart was studied. Results showed that the effective refractory period (ERP) of the atrioventricular conduction system was prolonged in six animals from 120 +/- 25 to 192 +/- 35 msec (p less than 0.02) on average. The ERP of the ventricle was shortened in four dogs from 153 +/- 36 to 123 +/- 17 msec (p less than 0.05). Specimens disclosed mononuclear cell infiltration in the atrioventricular node, the bundle of His, and the right and left bundle branches in eight of 12 cases and mild to moderate myocyte damage with cell infiltration in the ventricular septum of the same eight hearts. The ERP of the atrioventricular conduction system showed no change in four cases without mononuclear cell infiltration in the conduction system. These results suggested the feasibility of electrophysiologic monitoring as a means for detecting acute rejection in the prenecrotic stage in transplanted hearts.

Acute Disease↗

PubMedDate not supplied

Open aortic bioprosthesis at zero pressure. A new concept in glutaraldehyde fixation of tissue valve.

An experimental trial has been made to fix a porcine aortic valve in a semi-open position using 1 percent glutaraldehyde (open model). Four valves of open model xenograft were examined with use of our pulse-simulator. Four valves fixed in the closed position (closed model) and one untreated valve were studied for comparison. Comparison of the opening characteristics at the pump pressure of 120 gr/sq.cm revealed the significant difference in that the open model valves gave the simultaneous cusp opening with a circular orifice, while the closed model valves opened in sequence with irregular orifice. This relationship was substantiated by forward flow measurement. Analysis of the flow velocity curve confirmed the competence of the open model xenograft. These results suggest that the open aortic bioprosthesis may provide an improved hemodynamic function under low flow conditions.

Aortic Valve↗

PubMedDate not supplied

A comparative study between glutaraldehyde-preserved aortic and pulmonary heterograft valves in the tricuspid position in dogs.

Morphological observations have been presented on 10 metaperiodate-glutaraldehyde-preserved aortic heterograft valves and 5 pulmonary heterograft valves implanted into the tricuspid position for periods ranging from 7 to 183 days. It is recognized that there was a relatively minimal histological change in pulmonary valves. However, calcification of implanted aortic cusps was observed in 20% (2 out of 10) of cases and high incidence of thrombus formation on aortic cusps was recognized, although there were none on pulmonary cusps. It seems reasonable to presume that the high incidence of thrombus formation on the aortic valves is primarily due to the decreased pliability and stiffness of the cusps. It is concluded that the pulmonary valves rather than the aortic valves are recommended for tricuspid valve replacement.

Aldehydes↗