The effects of diisopropylmethylphosphonate on female mink: how medical intervention biased mortality data

This analysis retrospectively assessed the likelihood that medical intervention masked effects of diisopropylmethylphosphonate (DIMP) on female mink. Bucci et al. [Two-generation reproductive study in mink fed DIMP. Final report. Study no. TP-001. Prepared by Pathology Associates International, Jefferson, AR, USA, 1997] medically intervened in 24 out of 174 female mink to prevent mortality after an overdose of anesthetic was believed to have induced a life-threatening stress-syndrome. Bucci et al. [loc. cit.] dismissed the biological significance of the intervention since intervention occurred similarly in controls and treatment groups. The present investigation revealed that more (3-fold) DIMP-treated female mink surviving the intervention had abnormal physiological/clinical parameters at the time of intervention (9/10) than control female mink (3/9) (P<0.1). In addition, the severity of the physiological/clinical abnormalities increased with dose. These findings indicate that the DIMP treated female mink were more likely to have benefited from the intervention than the controls. The intervention, therefore, reduced the likelihood of observing treatment-related effects.