Comparison of low-level sarin and cyclosarin vapor exposure on pupil size of the gottingen minipig : Effects of exposure concentration and duration

The current studies estimated effective (miosis) concentrations of the nerve agents' sarin (GB) and cyclosarin (GF) as a function of exposure duration in the Gottingen minipig and determined dependency of the median effective dosage (ECT50) over time. Male and female Gottingen minipigs were exposed to various concentrations of vapor GB or GF for 10, 60, or 180 min. Infrared images of the pig's pupil before, during, and after nerve agent exposure were captured digitally and pupil area was quantified. An animal was classified “positive” for miosis if there was a 50% reduction in pupil area (as compared to baseline) at any time during or after the GB or GF exposure. Maximum likelihood estimation was used on the resulting quantal data to calculate ECT50 (miosis) values, with approximate 95% confidence intervals, for each of the six gender–exposure duration groups. As a group, male minipigs were significantly more sensitive to the pupil constricting effects of GF than were female minipigs. In male minipigs, GF...