Aluminium powder inhalations in the treatment of silicosis of pottery workers and pneumoconiosis of coal-miners.

Abstract

Haidane in 1918 postulated the theory that the dust of certain mineral rocks had an antidotal effect on the fibrogenie action of siliceous dusts, a theory which has since been put to the test by animal investigators. Kettle in 1932 showed that iron coated particles of quartz were inert when injected subcutaneously into animals, whereas uncoated quartz caused marked necrosis and cellular change in the subcutaneous tissues. In 1937 Denny, Robson and Irwin found that small quantities of metallic aluminium inhibited the solubility of siliceous material in the beaker, and that quartz particles coated with aluminium failed to produce fibrosis in the lungs of rabbits, whereas particles not so treated caused frank pulmonary fibrosis. Later, in 1939, these three authors working on rabbits showed that the fibrogenic action of quartz could be prevented if 1 % aluminium was given independently of the quartz. Gardner, Dworski, and Delahant (1944) were unable to substantiate Kettle's work using iron oxide, but obtained results with alumin ium hydroxide similar to those reported by Denny, Robson, and Irwin. These experimental findings on laboratory animals gave rise to the hypothesis that human silicosis might be prevented, or progression of the established disease arrested, by the prophylactic or therapeutic inhalation of aluminium powder. Subsequently workers in America and Canada published pre liminary findings on the value of aluminium inhala tions for the treatment of silicosis, and in 1946 Professor E. J. King and Dr. C. L. Sutherland visited Canada and America to review the whole question of aluminium therapy on behalf of the Medical Research Council. In 1947, after their extensive tour, they reported that although many centres claimed symptomatic improvement with this aluminium treatment there was no definite evidence that aluminium retarded the further development of silicosis, or that it caused regression of the established disease. They recommended that carefully planned and controlled investigations be made into the value of this treatment. This recom mendation was endorsed by the Aluminium Sub committee of the Industrial Pulmonary Diseases Committee, and the present report gives an account of the investigation that was carried out in the Stoke-on-Trent area to evaluate the merits of aluminium inhalations for the treatment of estab lished silicosis of pottery workers and pneumo coniosis of coal-miners. The object was to compare the relative efficacy of aluminium inhalations given in two very different doses (one of which was so low as to be effectively an inert control) in relieving symptoms, in improving the patient's functional capacity, and in retarding the progression of estab lished radiological changes.