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The Belousov-Zhabotinsky (BZ) reactions were used as typical examples of a nonlinear system far from equilibrium in connection with biological evolution. The virtual absence of gravity in the present work was given from the free-fall facility of Japan Microgravity Center (JAMIC) in Hokkaido. The reaction solution of BZ reaction was composed of bromate in sulfuric acid, 1,4-cyclohexanedione and ferroin to visualize the time development of patterns of chemical oscillations in the reaction-diffusion system. It is a bubble-free constitution in the aging of the reaction. Therefore, the setup constructed to collect image data via CCD cameras was simplified. The operation sequences of necessary devices were comprised of simple solid state relays which were started by a command from the operation room of JAMIC. The propagation profile of chemical patterns under microgravity of 10(-5) g was collected as image data for 9.8 s, and processed by a software of STM-STS2. In the aqueous solutions, propagation velocity of chemical patterns under microgravity was decreased to 80.9 % of that under normal gravity, owing to suppression of convection. On the other hand, in gel matrix, gravity did not influence the propagation velocity., (c1999 COSPAR. Published by Elsevier Science Ltd.)

Background: To achieve successful lung transplantation, it is essential to minimize reperfusion injury occurring as a result of metabolite accumulation during the preservation period or at the time of initial interaction of blood with constricted pulmonary vasculature. Initial reperfusion with warm crystalloid solution may be advantageous in preventing this injury., Methods: This study was designed to evaluate the effect of low-potassium (4 mmol/L) dextran (1%) solution as the initial warming solution after 6 hours of hypothermic storage. In 23 New Zealand White rabbits the lungs were flushed with low-potassium dextran solution (10 degrees C, 40 ml/kg, 600 cm H2O), excised, inflated with room air, and stored in a low-potassium dextran solution (10 degrees C) for 6 hours. After storage, the lungs were divided into two groups. Group 1 (n = 8) was reperfused with warm low potassium dextran for 4 minutes, at 37 degrees C followed by blood reperfusion for 30 minutes at 37 degrees C. Group II (n = 15) was reperfused only with blood for 30 minutes at 37 C. The mean pulmonary vascular resistance measured during cold flush and prior to storage was similar in both groups (group I = 20.0 +/- 5.9 mm Hg.sec/ml, group II = 19.3 +/- 1.9 mm Hg.sec/ml)., Results: During reperfusion, only 4 of the 15 lungs in group II maintained an acceptable (< 80 mm Hg) mean pulmonary artery pressure; six failed immediately. All eight lungs in group I completed the 30-minute reperfusion (p < 0.005). The mean pulmonary artery pressure was significantly less, and effluent oxygen tension was significantly greater in group I during reperfusion., Conclusions: In this experimental model, initial warm reperfusion with low-potassium dextran ameliorated the deleterious effects of reperfusion, thus providing an environment to improve lung preservation.

Background: The goal of organ preservation is maintenance of physiologic functions during extended extracorporeal storage., Methods: This study was designed to evaluate the efficacy of using low-potassium (4 mmol/L) dextran (1%) solution on lung function after 30 hours hypothermic (10 degrees C) storage and to compare this with lung function after no storage. With low-potassium dextran solution rabbit lungs were flushed (10 degrees C, 40 ml/kg, 60 cm H2O), excised, inflated (with room air), and either not stored (control; no preservation; n = 9) or stored in low-potassium dextran solution (10 degrees C) 30 hours (experimental group; n = 9)., Results: During the flush the infusion pressure and pulmonary vascular resistance for the two groups did not differ (17.56 +/- 1.3 versus 16.74 +/- 1.5 mm Hg/ml/sec). After either no preservation or after 30 hours of storage, the lungs were first reperfused with low-potassium dextran solution (37 degrees C) for 4 minutes and then with blood (37 degrees C) for 30 minutes at 100 ml/min. During the reperfusion period the mean pulmonary artery pressure and end-inspiratory airway pressure for the control and experimental groups did not differ. After reperfusion the wet and dry weights of the left lung were determined. The wet/dry ratio for the two groups did not differ (5.32 +/- 2.20 versus 4.70 +/- 2.70, respectively)., Conclusions: These data suggest that cold flush, cold storage, and initial warm perfusion with low-potassium dextran solution crystalloid preserve lung function after 30 hours of storage.