Some acute toxicological properties of cotton dust extract (CDE) and polymer (CDP) have been examined. Based on the LD(50) in mice, CDE and CDP administered ip., possess only moderate toxicity and, when expressed in terms of total dust, they may be regarded as practically non-toxic. Although the toxic manifestations resembled those produced by endotoxins, the latter contribute only partially to this action. At the high doses employed, acute falls in white blood cells and platelet counts were observed, in addition to decreases in food and water intake. Both dust fractions, when administered i.p., to mice and guinea pigs, were capable of releasing several intracellular enzymes into the blood stream. This indicated some degree of cell membrane damage but a single target site was not identified. On the basis of biochemical data there was no major involvement of the liver and the kidneys were unaffected. In general, CDP possessed either the same or a lower toxicological activity as/than CDE on a weight-for-weight basis. The effects of exposure of guinea pigs to CDE aerosol on the levels of LDH and acid and alkaline phosphatases were similar to those seen when CDE was given i.p. It is proposed that the guinea pig is a suitable model not only for 'pharmacological' studies with dust but also for toxicological investigations.

A panel of cardroom workers from an Iraqi cotton mill that appeared typical of such a population was examined in respect of blood and serum LDH. The only significant lowering of white blood cells was in the non-smoker byssinosis group. However, there were significantly raised proportions of eosinophils in the non-smoking groups (byssinotics and nonbyssinotics). A significant rise in serum LDH was observed in byssinotic subjects but only at the end of the working week. Although the similarity of the animal and human data is not extensive, the present work points to the necessity of further toxicological studies.