In an anesthetized canine model in which ischemia was induced by incremental air embo-lism, 16 animals were exposed to 1 hr of ischemia and monitored for 10 min (n = 4), 60 min (n = 6), or 240 min (n = 6). Fourteen animals were observed for corresponding periods without being subjected to ischemia 70 min (n = 4), 120 min (n = 4), or 300 min (n = 6). Autologous granulocytes were labeled with '"in and reinfused just before ischemia. At the conclusion of each experiment, a M C-iodoantipyrine autoradiographic blood flow study was performed. Granulocyte accumulation measured by gamma scintig-raphy (cpm/gm) occurred in the injured hemisphere of ischemic animals at 60 min in anterior brain segments and at 240 min in anterior, middle, and posterior segments. By means of a double-label autoradiography technique, clustering of punctate granulocyte images was detected in regions of low flow or heterogeneous flow in half of the animals at both 60 min and 240 min post ischemia. Granulocyte clustering did not occur in the autoradiograms of nonischemic animals. The results implicate granulocyte participation hi the acute phase of ischemic brain injury and signal a convergence of hemostatk and inflammatory processes during the immediate postischemic period.

After storage in the liquid state at 4 C for up to three weeks, washing with sodium chloride solutions, and storage in a sodium chloride-glucose-phosphate solution for 24 hours at 4 C, dog red blood cells had excellent post-transfusion survival. After freeze-preservation with 40% W/V glycerol at -80 C or with 20% W/V glycerol at -150 C, thawing, washing with sodium chloride solutions, and storage in a sodium chloride-glucose-phosphate solution for 24 hours at 4 C, dog red blood cells had satisfactory recovery values in vitro, acceptable 24-hour post-transfusion survival and long-term survival values, and normal oxygen transport function. Controlled addition and removal of the cryoprotectant, glycerol, helped reduce the amount of osmotic damage to the red blood cells and enhanced freeze-preservation. Osmotic damage can also be prevented by warming the dog blood to a temperature of 22 +/- 2 C prior to centrifugation to concentrate the red blood cells and remove the plasma. This step enhances removal of the cold agglutinins. Another processing step used by the authors was to add a sodium chloride solution to the dog red blood cells before adding the glycerol solution in order to eliminate rouleaux formation.

The concentration of the plasticizer, di-2-ethylhexyl phthalate (DEHP), in the plasma was measured after storage of the whole blood in polyvinylchloride plastic bags a t 4 C for u p to 38 days in either ACD or CPD. The plasma from ACD-stored whole blood contained more DEHP than that from CPD-stored whole blood. The continuous-flow centrifugation washing procedures removed about 98 per cent of the DEHP from ACD whole blood stored for 33 days at 4 C.

Normal human monocytes were negatively selected from leucapheresis cell suspensions by countercurrent centrifugation-elutriation in high yield with a mean purity of 93.5%. The combination of the novel methods of negative cell selection and suspension cell culture has provided the opportunity to study serially over several days the morphologic and functional changes of monocytes from a single donor as they matured in culture to typical macrophages. Human monocytes nearly double in size during the first week of culture, experiencing near daily increases in cell volume. This was associated with changes in the ultrastructure of these cells, including the development of numerous small knob-like projections on the cell membrane and the proliferation of microtubules and filamentous structures within the cell cytoplasm during the first 6 days of culture. Peroxidase activity declined during the first 4 days of culture, whereas 5'-nucleotidase activity was acquired during the first 48 h of culture. Lysozyme activity in the cultures increased form day 2 to day 6 of culture. The phagocytic capacity of monocytes for igG-coated erythrocytes increased dramatically during the first week of culture, but the cytotoxic capability of monocytes against similar targets in an antibody-dependent cytotoxicity assay declined to nearly half of base-line levels by day 2 of culture and remained at this diminished level during subsequent days of culture.

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The efficiency of washing liquid-stored red blood cells and red blood cells frozen with high or low glycerol concentrations was evaluated by measuring the recovery of red blood cells in vitro, supernatant hemoglobin, extracellular potassium and red blood cell potassium levels, supernatant osmolality, residual 125I albumin, glycerol, hypoxanthine, and di-2-ethylhexyl phthalate (DEHP) levels. Four commercial washing systems were studied, three which used sodium chloride solutions with serial or continuous-flow centrifugation and one which used sugar solutions and dilution/agglomeration. Washing was most efficient using sodium chloride solutions in the IBM Blood Processor, an automated serial centrifugation procedure and in the Fenwal Elutramatic, a continuous-flow centrifugation procedure. Less efficient washing was achieved in the Haemonetics Processor 15, a continuous-flow centrifugation procedure and the least efficient washing occurred using the original and modified dilution/agglomeration procedures. To achieve the most efficient washing, three principles must be utilized: concentration of the red blood cells to hematocrit values of 90 per cent, prior to washing or freezing. Liquid-stored red blood cells concentrated to hematocrit values of 90V per cent should be diluted with hypertonic sodium chloride solutions prior to recovery and washing. Red blood cells containing 20 per cent or 40 per cent W/V glycerol should be diluted with hypertonic sodium chloride solutions before recovery and washing. Finally, on-line dilution should be achieved in the washing systems that use continuous-flow centrifugation.

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