Platelet concentrates (PC) were isolated by serial differential centrifugation from units of blood anticoagulated with one of the citrate-phosphate-dextrose-adenine solutions (CPDA-1, CPDA-2, CPDA-2). The platelet concentrates were frozen with six percent dimethylsulfoxide at 2-3 degrees C per minute and stored in a -80 degrees C mechanical freezer in polyvinyl chloride or polyolefin plastic containers. After frozen storage at -80 degrees C for up to three months, the concentrates were thawed at 42 degrees C within 2.5 to 4.0 minutes, washed with autologous plasma, two percent dimethylsulfoxide and 10 percent acid-citrate-dextrose solution, and then resuspended in plasma. The washed platelets were labeled with 51Cr and transfused back to the donor from whom they had been obtained. In vitro recovery from whole blood to platelet concentrate was 70.5 +/- 17 percent (mean +/- one SD). In vitro freeze-thaw-wash recovery determined by phase microscopy was 78.5 +/- 12.8 percent, in vivo 51Cr platelet recovery two hours after transfusion was 41.3 +/- 13.5 percent, and the platelets had a linear lifespan of about eight days. A single unit of previously frozen platelets shortened an aspirin-prolonged bleeding time two and 24 hours after infusion. Results were similar with platelets isolated from all three anticoagulants and stored in both plastics. The results also were comparable to previous findings in this laboratory with platelets isolated from ACD and CPD anticoagulated blood.

Adenine↗

PubMedDate not supplied

Implementation of depth-dependent soil concentrations in multimedia mass balance models.

In standard multimedia mass balance models, the soil compartment is modeled as a box with uniform concentrations, which often does not correspond with actual field situations. Therefore, the theoretically expected decrease of soil concentrations with depth was implemented in the multimedia model SimpleBox 3.0. The effects of this implementation on the model outcomes were explored for nine compounds in four environmental compartments. For compounds with a low penetration depth, the new model predicts substantially higher or lower concentrations in the vegetation compartment than the old model. For those compounds, predicted concentrations in surface water and air were higher in the new model, but the deviations from the old model were smaller than in the vegetation compartment. For compounds with a large penetration depth, the model adaptations show little effect. No field study was carried out to validate the results of the model calculations, but we did collect measured data on concentrations in vertical soil profiles from literature. According to those data, we concluded that the implementation of depth dependent soil concentrations might be a useful extension for steady state multimedia mass balance models. More field study has to be carried out to validate the model outcomes.

Databases, Factual↗