Biomedical subjects

R Matsuwaka

Publications and source records attributed to R Matsuwaka.

59 records · Page 4Linked to original sources

PubMedDate not supplied

Effects of terminal cardioplegia with leukocyte-depleted blood on heart grafts preserved for 24 hours.

Canine hearts immersed in modified Collins solution were transplanted heterotopically (n = 23) and orthotopically (n = 15) to evaluate the effect of terminal warm-blood cardioplegia with or without leukocyte depletion. As the index for graft function, preload recruitable stroke work was measured in both series before harvesting (control) and after transplantation (percentage). The heterotopic hearts were divided into four groups (group 1 to 4) according to the preservation method; hearts were preserved for 3 hours in group 1 and for 24 hours in groups 2, 3, and 4. Simple terminal warm-blood cardioplegia was applied in group 3, and terminal warm-blood cardioplegia with leukocyte depletion was used in group 4. In the orthotopic series, five hearts were transplanted soon after harvesting (group 5) to simulate on-site transplantation, and the remaining ten hearts were transplanted after 24 hours of hypothermic preservation without and with terminal warm-blood cardioplegia with leukocyte depletion (groups 6 and 7, respectively). Among the heterotopic transplants, the percentage of preload recruitable stroke work was highest in group 4 (91% +/- 6%, 51% +/- 4%, 83% +/- 10%, 140% +/- 11% in groups 1, 2, 3 and 4, respectively). All orthotopic transplants in groups 5 and 7 were weaned from cardiopulmonary bypass without inotropic support and without significant differences in cardiac function between groups 5 and 7 (percentage of preload recruitable stroke work, 99% +/- 10% versus 102% +/- 2%; cardiac output, 122 +/- 10 versus 140 +/- 22 ml/kg/min). No orthotopic transplants in group 6 could be weaned from cardiopulmonary bypass, even with inotropic support.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Experimental evaluation of a new type of heparin-bonded polyurethane.

A new type of heparin bonding method using polyurethane (H-PU) in an ionically equivalent manner was examined experimentally. In vitro testing of polyvinylchloride tubes with this coating showed that the behavior of the heparin was attributed to the activation of retained heparin on the surface. After 4 hrs of heparinless arterio-arterial bypass in a canine model with a central shear rate of 25 sec-1 (inner diameter, 0.8 x 80 cm), macroscopic and scanning electron microscopic examinations showed that the H-PU coated tube had better antithrombogenicity than that of a conventional PU coated tube (Pellethane). These results suggest that this heparin bonding method with PU appears to have good antithrombogenicity with possible long durability.

Animals↗

PubMedDate not supplied

The development of a clinically relevant canine model of postperfusion syndrome.

Investigation into the complex etiology of the postperfusion syndrome (PPS) has been limited by access to only retrospective human case studies, and performance of animal studies that examine biochemical predictors of injury rather than the PPS itself. To determine whether a reproducible canine model of the clinical syndrome was possible, seven dogs underwent cardiopulmonary bypass (CPB) with a bubble oxygenator for 0 (n = 1, sham), 2 (n = 1), 4 (n = 1), and 6 (n = 4) hours. Arterial oxygenation, chest radiographs, serum creatinine, and total leukocyte and platelet counts continued to change through the second postoperative day, illustrating the need for prolonged follow-up (48 hours) to accurately detect postperfusion organ dysfunction. The dogs that did not undergo CPB for 6 hours (n = 3) did not develop important pulmonary dysfunction postoperatively, but three of the four dogs undergoing 6 hours of CPB developed profound, persistent, arterial hypoxemia associated with radiographic, histologic, and hemodynamic evidence of severe PPS. Early evidence of renal dysfunction was also apparent within 84 hours of 6 hour CPB. It is concluded that the canine long duration (6 hour) CPB model, with prolonged (48 hour) postoperative monitoring, generates a reproducible, clinically relevant model of human PPS.

Animals↗

PubMedDate not supplied

Experimental evaluation of a heparin coated ECMO system simplified with a centrifugal pump.

A heparin coated cardiopulmonary bypass system was evaluated for canine veno-venous extracorporeal membrane oxygenation (ECMO). The ECMO system consisted of a hollow fiber membrane oxygenator and pediatric centrifugal pump but no reservoir. In Group 1 (N = 6), the ECMO system was coated with a covalent, heparin-binding method, except for the centrifugal pump, and animals underwent ECMO without systemic heparinization. In Group 2 (N = 4), the same system without the heparin coating was used under full heparinization. During 12 hours of ECMO with a bypass flow of 500 ml/min, there were no significant differences in gas exchange or blood trauma between the two groups. There was no apparent macroscopic thrombus formation in either group. In addition, it was suggested that Group 1 had less activation of platelets on the blood-contacting surfaces compared with Group 2. This ECMO system, with simplified circuits using a centrifugal pump, showed efficient gas exchange and antithrombogenicity when coated with heparin using a covalent binding method comparable to the non heparin coated system requiring systemic heparinization.

Animals↗

PubMedDate not supplied

Attenuation of pulmonary leukocyte sequestration during extracorporeal circulation by a new c-AMP phosphodiesterase inhibitor.

Activated leukocytes may have an important role in developing complement-related lung injury, with pulmonary leukocyte sequestration in the presence of blood-material interaction in cardiopulmonary bypass and hemodialysis. The authors evaluated the effects of a new cAMP phosphodiesterase inhibitor (DN-9693) on leukocyte aggregation in vitro, utilizing canine heparinized blood and pulmonary leukocyte sequestration during extracorporeal circulation (ECC) in dogs. On in vitro evaluation, DN-9693 inhibited the leukocyte aggregation response to leukotriene B4 in a dose response manner; the aggregation response elicited by contact with a membrane lung was inhibited by a 50% inhibition dose of approximately 0.2 mumol/L. Leukocyte kinetics were assessed in a venovenous bypass system with a silicone hollow fiber membrane lung. The control group (n = 6) without DN-9693 developed a reduction in the arterial leukocyte count of 55 +/- 17% at 2 minutes of ECC. The transpulmonary difference in leukocyte count (pulmonary artery count minus systemic artery count) was significantly increased (P less than 0.05) from -175 +/- 206/microliters at baseline to 1225 +/- 330/microliters after 2 minutes of ECC. In the DN-group (n = 4, DN-9693; 60-80 micrograms/kg/min), there was no significant reduction in the arterial leukocyte count during ECC, and the transpulmonary difference showed no significant increases (75 +/- 386/microliters; baseline, versus 125 +/- 263/microliters; 2 minutes of ECC). These results suggest that DN-9693 inhibits the aggregation of leukocytes in the presence of blood-material interaction in vitro, and also prevents pulmonary leukocyte sequestration induced by ECC, with attenuation of systemic leukocyte depletion.

3',5'-Cyclic-AMP Phosphodiesterases↗