Untoward effects associated with practolol administration: oculomucocutaneous syndrome

Keratoconjunctivitis sicca, conjunctival scarring, fibrosis, metaplasia, and shrinkage developed in 27 patients as an adverse reaction to practolol. Rashes, nasal and mucosal ulceration, fibrous or plastic peritonitis, pleurisy, cochlear damage, and secretory otitis media also occurred in some cases. Three patients suffered profound visual loss though most retained good vision. Symptoms and signs improved on withdrawal of the drug, but reduction of tear secretion persisted in most patients.

Vitamin A (retinyl acetate) and benzo(alpha)pyrene-induced respiratory tract carcinogenesis in hamsters fed a commercial diet

Male Syrian hamsters fed a commercial diet were given a series of 12 intratracheal instillations of 3 mg benzo (alpha) pyrene adherent to 3 mg Fe2O3 in 0.2 ml 0.15 M NaCl at weekly intervals. After the last instillation, the hamsters were randomly assigned to receive either 100, 1600, or 3300 (later reduced to 2400) mug retinyl acetate per week in divided intragastric doses. Hamsters in the 2400-mug retinyl acetate group had a significantly higher incidence of respiratory tract tumors than those in the group given 100 mug retinyl acetate per week. Liver vitamin A stores increased dramatically in the groups given 1600 and 2400 mug retinyl acetate and corresponded to the administration of retinyl acetate p.o. Serum vitamin A values were not consistently related to retinyl acetate administration or to hepatic stores of vitamin A.

Effects of tobacco on the ear

The origin of the cholesteatoma matrix remains controversial although most investigators favor the hypothesis of epidermal migration from a perforated tympanic membrane. The metaplasia theory of the histogenesis of cholesteatoma is rarely considered relevant today. This study demonstrated that following repetitive exposures to a potent irritant such as tobacco tar, stratified squamous epithelial metaplasia can occur in the aural bulla of the cat. The investigation included six cats with indwelling polyethylene tubes surgically inserted into both aural bullae. In each cat the left bullae served as a control and 0.2 ml of tobacco tar from a cigarette smoking machine was instilled at weekly intervals into the right bullae. The animals were sacrificed in sequence at weekly intervals one week following the instillations so that the first animal had two weeks exposure and the sixth, seven weeks. In addition to metaplastic stratified squamous epihelium, goblet cell metaplasia was also seen.