The prophylactic use of polyvinylpyridine-N-oxide (PVNO) in baboons exposed to quartz dust

Twelve baboons were exposed to a quartz dust cloud. Four of these were also given polyvinylpyridine-N-oxide (PVNO) by aerosol and four received PVNO by aerosol and injection. A prophylactic effect was demonstrated during the course of treatment, but when treatment stopped the silicosis progressed to the same degree of severity as in the untreated animals.