No abstract

Oxytetracycline hydrochloride (OTC) was delivered by aerosol to healthy 3-week-old turkeys. Trachea, lung, and plasma were evaluated for OTC levels at 1, 4, 8, 12, 24, and 48 hours after aerosol exposure. In Expt. 1, 15 poults in a modified Horsfall unit were exposed to 1 g OTC/m3 of air using a DeVilbiss ultrasonic nebulizer. In Expt. 2, 25,000 poults in a commercial confinement unit were exposed to 0.075 g of OTC/m3 of air using a Fogmaster fogger. In each case, initially high tracheal and lung OTC concentrations were obtained. OTC levels in the trachea fell to less than 1 microgram/g between 4 and 8 hours postexposure. Plasma OTC levels remained low throughout both experiments. Oxytetracycline was still detectable in room air 60 min after aerosol exposure and before ventilation was restored. This method of administration may have promise for use in respiratory infections, but additional studies are needed to further define the use of aerosol therapy in poultry production units.

Sheep umbilical arteries and veins contracted to serotonin at concentrations less than those of prostaglandins. Also, serotonin produced a greater maximal contraction relative to the prostaglandins. PGF₂Α and PGE₂ were essentially equiactive in inducing contractions while PGE₁, and PGF₁Α were clearly less active than PGF₂Α or PEG₂