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We studied the effect of aspirin and sulfinpyrazone on changes in platelet count, thromboxane B2 production, and pulmonary vascular resistance following the onset of veno-venous membrane oxygenator perfusion in sheep. Perfusion under identical circumstances was performed in three groups of animals, with one group serving as controls, one group receiving pretreatment with 1.5 grams of sulfinpyrazone iv, and one group receiving pretreatment with aspirin 50 mg/kg, iv. Both aspirin and sulfinpyrazone eliminated the rise in thromboxane B2 and the increase in pulmonary vascular resistance seen in control animals. Platelet preservation was improved significantly with sulfinpyrazone pretreatment, but not affected by aspirin. We conclude that sulfinpyrazone and aspirin have different mechanisms of action as far as platelet preservation during extracorporeal perfusion is concerned. The major difference may be sulfinpyrazone's ability to reduce platelet adhesion to the membrane surface. Since both aspirin and sulfinpyrazone eliminated the pulmonary vascular-response, but only sulfinpyrazone preserved platelets, it is apparent that the pulmonary vascular response is more closely related to thromboxane synthesis than to platelet disappearance.

Penning and Kingdon ion traps have been used to study low-energy multiply-charged ions with charge states up to 80+ during the last few years. The ions have been captured into the traps from beams of external multiply-charged ion sources, or have been produced inside the trap. Measurements of cross sections for electron capture from neutrals to ions and studies of relative double electron capture rates have been completed. The lifetimes of metastable levels of ions, precision spectroscopy on multiply-charged ions in traps, and cooling of trapped ions using lasers, ion-ion elastic collisions, and parallel-tuned circuits, are briefly reviewed. Prospects for the future of highly-charged ions in traps are also discussed.

Four separate experiments were conducted at three localities in Victoria to compare the growth and carcase characteristics of steers and heifers either as entire (not pregnant), spayed, fitted with a HEIGRO intravaginal device, or pregnant. All treatments were compared in the major experiment of the series with two or more of the treatments compared in the other experiments. A total of 212 yearling cattle was used in the experiments, which were conducted mainly at pasture for periods of 4-11 months. The differences between the growth rate of steers and entire heifers (3.5%) and entire and spayed heifers (5.0%) were not significant. Pregnant heifers gained weight faster during mid-pregnancy (P < 0.05) but their dressing percentage and carcase weight were lower (P < 0.05) than all other groups. There were few significant differences in fat depth and only small differences in any of the carcase characteristics measured. We conclude that entire heifers grew and fattened as well as steers and that neither spraying nor the use of the HEIGRO device improved carcase weight gain but that pregnancy reduce it.