Search PubMed for references concerning: Crotoxyphos
Title: Enantioselective acetylcholinesterase inhibition of the organophosphorous insecticides profenofos, fonofos, and crotoxyphos Nillos MG, Rodriguez-Fuentes G, Gan J, Schlenk D Ref: Environ Toxicol Chem, 26:1949, 2007 : PubMed
A large number of organophosphorous insecticides (OPs) are chiral compounds, and yet enantioselectivity in their environmental fate and effects is rarely addressed. In the present study, we isolated individual enantiomers of three OPs, profenofos, fonofos, and crotoxyphos, and evaluated enantioselectivity in their inhibition of acetylcholinesterase (AChE). Acetylcholinesterase inhibition by the enantiomers and racemates was determined in vivo in the aquatic invertebrate Daphnia magna and in Japanese medaka (Oryzias latipes) as well as in vitro with electric eel (Electrophorus electricus) and human recombinant AChEs. The overall results showed variable sensitivity between AChE enzymes from different species as well as variable magnitude of enantioselectivity in enzyme inhibition. The (-)-enantiomer of profenofos was 4.3- to 8.5-fold more inhibitory to AChE in vivo, whereas (-)-fonofos was 2.3- to 29-fold more potent than the corresponding (+)-enantiomer. The (+)-enantiomer of crotoxyphos was 1.1- to 11-fold more inhibitory to AChE than the (-)-enantiomer. In contrast, the in vitro results showed (+)-profenofos to be 2.6- to 71.8-fold more inhibitory than the (-)-enantiomer and (-)-crotoxyphos to be 1.6- to 1.9-fold more active than the (+)-enantiomer. The reversed direction of enantioselectivity observed between the in vivo and in vitro assays suggests enantioselectivity within toxicodynamic processes such as uptake, biotransformation, or elimination. Findings from the present study provide evidence of enantioselectivity in the AChE inhibition of chiral OPs in nontarget organisms and indicate the need to consider enantiomers individually when assessing environmental risk of these chiral pesticides.
Title: Toxicity and interaction of topical organophosphate insecticide dichlorvoscrotoxyphos and phenothiazine anthelmintic in sheep previously exposed to both drugs Mohammad FK, St Omer VV Ref: Vet Hum Toxicol, 27:181, 1985 : PubMed
Toxicity and interaction of topical application of dichlorvoscrotoxyphos (D-C) insecticide and phenothiazine anthelmintic (PTZ) given in the diet were studied in 4 groups of 4-5 lambs each that had had prior drug exposure. In a study reported previously each lamb in groups 1 and 2 was sprayed with 3 biweekly topical applications of 1550 ml of 0.25% D-C emulsion. Groups 1 and 3 were treated with PTZ (12.5 g/sheep initially and 4 days later with 6.25 g every 3 days for 9 treatments). Group 4 was the control. Following termination of that study the animals were given a 30-day nonmedicated period and reused in the present study as described below. Each lamb in group 1 and 3 was challenged with PTZ given in the diet (1g/sheep/day for 3 days). On the third day of PTZ administration, each lamb in group 1 and 2 was sprayed with 1 gallon of 0.25% D-C emulsion. The 4th group served as a control. Following D-C spray, clinical signs of toxicosis were seen within 17 min in 56% of the exposed lambs regardless of concurrent PTZ treatment. The erythrocyte acetylcholinesterase (EACE) activities of the D-C exposed groups were significantly (P less than 0.05) depressed on post-treatment days (PTD) 1 and 3 regardless of the PTZ treatment. The base-line EACE values were reestablished on PTD 18. The PTZ alone was not toxic and did not inhibit EACE activity
