The Se content of aquatic organisms was lowest in aquatic plants, varying from 0.02 to 0.14 ppm (dry wt). Plankton samples contained from 1.1 to 2.4 ppm, fishes cultured in ponds 0.5 to 0.9 ppm, and fishes from natural environments 1.0 to 2.9 ppm. The phytoplankter, Scenedesmus dimorphus, actively concentrated 75Se‐selenomethionine, but neither actively nor passively concentrated inorganic selenite. The zooplankton, consisting mostly of Daphnia pulex, absorbed 75Se from selenite. In aquariums fish concentrated only a small amount of organic or inorganic Se directly from water, but did concentrate Se from food.

Summary Effects of graded intensity exercise on plasma lipids was studied in Standardbred and Finnish‐bred Trotters. The rate of lipolysis indicated by the elevated plasma concentrations of glycerol increased parallel with the intensity of the trot in the Standardbreds, but not as clearly in the Finnish‐bred trotters. During the exercise plasma triglyceride concentration increased significantly and the increase correlated with the intensity of the exercise as well as the activity of lipolysis. Together with the increase in plasma triglycerides, there was a parallel increase in the pre‐beta fraction of lipoproteins which suggests that the hepatic synthesis of triglycerides was increased. It was calculated that about one third of the nonesterified fatty acids released in lipolysis during the high‐intensity exercise is oxidized and the remainder is used for resynthesis of triglycerides. Since there were interstrain differences in the concentrations of triglycerides and glycerol after the high‐intensity exercise it is suggested that the differences may be of some value in the estimation of recovery after submaximal exercise. Zusammenfassung Durch Arbeit induzierte vorübergehende Hyperlipidämie beim Sportpferd Bei gewöhnlichen Trabern sowie bei finnischen Trabern wurde der Einfluß abgestufter Arbeit auf die Plasmalipide untersucht. Der die Lipolyserate widerspiegelnde Anstieg der Plasma‐Glycerin‐Konzentration nahm bei den gewöhnlichen Trabern mit der Intensität des Trabs zu. Bei den finnischen Trabern manifestierte sich dies weniger deutlich. Die Plasma‐Triglycerid‐Konzentration nahm während der Arbeit signifikant zu. Der Anstieg der Plasma‐Triglycerid‐Konzentration war dabei mit der Intensität des Trabs und der Lipolyseaktivität korreliert. Mit dem Plasmatriglyceriden nahm die prae‐beta‐Fraktion der Lipoproteine zu. Dies spricht für eine Steigerung der Triglyceridsyn‐these in der Leber. Rechnerisch wurde ermittelt, daß etwa ein Drittel der während intensiver Arbeit bei der Lipolyse freigesetzten Fettsäuren oxidiert werden und daß der Rest zu Triglyceriden resynthetisiert wird. Da sich nach intensiver Arbeit Rasseunterschiede in den Plasma‐Konzentrationen von Triglyceriden und Glycerin ergeben, könnten diese Unterschiede unter Umständen für die Beurteilung der Erholung nach submaximaler Belastung von Bedeutung sein.

We describe an outbreak of human cryptosporidiosis in 5 veterinary students in contact with experimentally infected calves. All persons experienced symptoms of gastroenteritis, with the main complaint of diarrhoea lasting for 1-13 days. The persons recovered spontaneously; one was hospitalized for 10 days. The diagnosis was based on the demonstration of Cryptosporidium oocysts from stools by the smear method and the formalin-ether concentration method, both combined with the acid-fast staining technique. Both methods gave almost equal results. The role of Cryptosporidium as an occupational risk is discussed.

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