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Objectives Bovine and human blood has been widely used for in vitro hemolysis testing to evaluate centrifugal cardiac assist pumps. However, results from such tests are complicated by variations in the susceptibility of individual red blood cells to shear. The objective of this study was to evaluate the use of microcapsule suspension as an alternative to bovine or human blood for hemolysis testing.Methods Microcapsule suspensions of 100 µm maximal diameter (average 79.1 µm) with a polyurethane membrane were used. Each microcapsule contained a leuco dye, which was used to measure “hemolysis” in the suspension after exposure to mechanical stress. Six centrifugal pumps were used to measure and compare the hemolysis values of microcapsule suspensions, bovine blood and human blood.Results Correlations were significant between the hemolysis values measured using microcapsule suspensions and those using bovine blood (R = 0.965, p = 0.002) and human blood (R = 0.940, p = 0.005).Conclusions Microcapsule suspension can be successfully used instead of blood to compare the relative hemolytic performance of centrifugal blood pumps.

Four calves were maintained on low-magnesium milk from birth to about 20weeks of age. Severe hypomagnesaemia occurred in them all and typical signs of hypomagnesaemic tetany occurred in two. No marked changes occurred in other plasma electrolytes.

A total of 108 weanling male rats was assigned to a 3 × 3 factorial experiment with three dietary iodine levels: 0.68 (high), 0.23 (medium), 0.08 ppm (low); and 3 diets: a basal diet, a high-nitrogen-hay diet containing 40% hay from a plot treated with 450 kg nitrogen/hectare and a low-nitrogen-hay diet with 40% hay from a plot treated with 34 kg nitrogen/hectare. An attempt was made to equalize many essential nutrients. After a 30-day feeding period, there were no significant differences in body weight gain among treatments. For rats fed the basal diet, the high-nitrogen-hay diet and the low-nitrogen-hay diet, respectively, average weights of the thyroid glands were 16.7, 22.0 and 19.0 mg; average heights of the thyroid epithelial cells were 3.9, 5.7 and 4.9 μ; and average 24-hour postdose 131I thyroid levels were 15.2, 23.5 and 24.4% of dose. For groups receiving the high, medium and low dietary iodine, respectively, average weights of thyroid glands were 17.7, 17.4 and 22.6 mg; average heights of epithelial cells were 3.6, 4.2 and 6.7 μ; and average 131I levels in the thyroids were 9.9, 18.7 and 34.5% of the dose. Goiter was associated with inclusion of forage in the diet and, for two parameters, was intensified by intensive nitrogen fertilization of the soil but responded to iodine supplementation. It is suggested that nitrate is partly, but not entirely, responsible for the changes associated with intensive nitrogen fertilization.

Three experiments involving a total of 32 pigs were conducted to study the histidine requirement of baby pigs.