First record of onion leaf blotch (Mycosphaerella allii-cepae) in Argentina

In 1990, onion leaf blotch was observed for the first time in the Lower Rio Colorado Valley (Province of Buenos Aires), the most important onion-producing region of Argentina. Since then, the disease has been found in other production areas of this country. Infections on shallot have also been recorded. The causal agent, Mycosphaerella allii-cepae , was identified on the basis of symptoms, fungus morphology (as its anamorph Cladosporium allium-cepae ) and successful artificial inoculations on onion plants. Although the disease has been present in all seasons since 1990, epidemics of any importance have not been observed in the main crop of dry onions. This is the first record of onion leaf blotch for Argentina.     

Pharmacokinetics of digoxin in cattle

Digoxin was administered as a single intravenous injection of 22 micrograms/kg to six cattle. The resulting serum concentrations were fitted by both a bi- and tri-exponential equation with the latter providing the best fit to the data of a majority of the animals. The biological half-life of digoxin in cattle was found to be 7.8 h. This relatively short half-life in comparison to other animal species dictates that digoxin should be administered more frequently to cattle to provide therapeutic concentrations in serum without broad fluctuations in serum concentrations. Computer simulations of various intravenous dosage regimens suggested that a loading dose of 22 micrograms/kg followed by an infusion of 0.86 micrograms/kg/h would offer the greatest safety and efficacy in bovine patients.     

ASPECTS OF THE PHYSIO-PATHOLOGY OF PARASITIC GASTRITIS IN THE SHEEP

Sheep and calves prepared with separated, innervated pouches made from the acid secreting region of the abomasum were given single or multiple infections of Ostertagia spp and comparisons were made of the secretory changes of parasitised and non-parasitised mucosa by means of cannulas placed in the abomasum and pouch. Contrary reactions of the parasite-free pouches and infected main part of the abomasum are described and explained in terms of a two-part hypothesis. The inhibitory effect on acid secretion of the abomasum (resulting in its contents being pH 5 to 7) was postulated to be due to the direct suppressive effects of substances released locally by parasites or injured host tissues, whereas increased secretion of the hormone, gastrin, was thought to account for the stimulatory effects of infection on acid secretion from the pouches. In sheep treated with anthelmintic and then reinfected the inhibitory effects on abomasal pH were not obtained. The hypersecretion from the pouches still persisted.