Inhibition of non-specific leukocyte esterase activity. Absence of monocyte esterase activity due to phosphoric and thiophosphoric acid ester intoxication.

In vitro evaluation of the effect of five insecticidal phosphoric and 11 thiophosphoric acid esters on different, non-specific human leukocytes esterases indicated that most of the organic phosphor compounds studied inhibited the activity of neutral alpha-naphthylacetate esterase, alpha-naphthylbutyryl esterase, and naphthol AS acetate esterase, i.e. the monocyte esterases. The extent of inhibition was dose dependent; the inhibiting dose being identical for the various non-specific esterases. Reactivation with Obidoxim was not successful. Monocyte esterase activity in a human survivor of E 605 intoxication was detectable only after serum acetylcholinesterase had returned to normal levels. The organic phosphor compound studied, however, inhibited neither acid alpha-naphthylacetate esterase nor naphthol AS-D chloroacetate esterase activity.