The treatment of experimental silicosis with compound 48/80.

To treat established silicosis it would appear to be necessary to inactivate the dust in the lungs in order to prevent further toxic action and permit the repair of what damage is reversible. The drug used would presumably need to reach phagocytic cells which have transported the dust from the alveoli to the interstitial tissue and lymph nodes. In the conditions of experimental silicosis, aluminium has a protective effect (Dworski, 1955) but its administration to man by inhalation has not been proved to benefit the disease when once established (Kennedy, 1956). It is not certain that inhaled aluminium powder has the capacity to reach silica in the tissues and it is possible that soluble antagonists would prove more effective. In an earlier communication (Marks, 1957), it was reported that compound 48/80, an organic base used experimentally as a histamine liberator, protects phagocytic cells in tissue culture against the toxic effect of silica dust. The degree of protection observed appeared sufficiently high to merit a study of the drug's activity in vivo. Mice were used because of their relatively low susceptibility to histamine and because a convenient technique has been described for inducing silicosis in them (Zaidi, King, Harrison, and Nagelschmidt, 1956).