Piao FY

References (2)

Title : Pharmacokinetics and neurotoxicity of dipterex in hens. A comparative study of administration methods - Xie_1998_J.Toxicol.Sci_23_25
Author(s) : Xie X , Piao FY , Tian Y , Yamauchi T
Ref : Journal of Toxicological Sciences , 23 :25 , 1998
Abstract : We compared the tissue concentration of dipterex and the inhibition of the neuropathy target esterase (NTE) activity among groups of hens (n = 8 each) which were intravenously (i.v.), subcutaneously (s.c.) or orally (p.o.) administered the insecticide dipterex. The tissue concentrations of dipterex in the s.c. group were higher than those in the i.v. and p.o. groups. When dosed subcutaneously, the tissue concentration of dipterex was high in the brain, spinal cord and muscle at 3 hr after dosing and then concentrated in the spinal cord and muscle for the subsequent 3 hr. When dosed intravenously or orally, dipterex was evenly dispersed in various tissues. All hens treated with dipterex showed acute neurotoxic signs within 15 min after dosing. The hens dosed intravenously recovered from this acute poisoning within 3 hr, and the hens dosed orally recovered within 6 hr, while the hens dosed subcutaneously recovered within 24 hr after dosing. One hen in the s.c. group exhibited acute neurological sequelae following the acute poisoning. In addition, the loss of body weight was the largest in the s.c. group (157 +/- 49 g), moderate in the i.v. group (133 +/- 91 g), small in the p.o. group (96 +/- 54 g) and the smallest in the PMSF (phenylmethanesulfonyl fluoride, which was dosed to promote delayed neuropathy) group (80 +/- 49 g). In the untreated hens, the activity of NTE in both the cerebrum and cerebellum was higher than that in the midbrain (p < 0.01). There was no difference in NTE activity between the cerebrum and cerebellum. In both the cerebrum and midbrain, the inhibition of NTE activity in the p.o. group was less than that in the i.v. and s.c. groups, and no difference was found between the i.v. and s.c. groups. In the cerebellum, the inhibition of NTE activity in the s.c. group was larger than that in the i.v. and p.o. groups. These results indicate that the s.c. dosing of dipterex results in a stronger neurotoxicity compared to i.v. and p.o. dosing. However, it was difficult to induce the clinical signs of delayed neuropathy with any administration of dipterex in hens, even when the promotion of delayed neurotoxicity of dipterex was attempted with PMSF or double doses of dipterex itself.
ESTHER : Xie_1998_J.Toxicol.Sci_23_25
PubMedSearch : Xie_1998_J.Toxicol.Sci_23_25
PubMedID: 9513919

Title : Delayed neuropathy and inhibition of soluble neuropathy target esterase following the administration of organophosphorus compounds to hens - Tian_1998_Tohoku.J.Exp.Med_185_161
Author(s) : Tian Y , Xie XK , Piao FY , Yamauchi T
Ref : Tohoku J Exp Med , 185 :161 , 1998
Abstract : Delayed neuropathy and inhibition of soluble neuropathy target esterase (NTE) and acetylcholinesterase (AChE) activities in different regions of brain and spinal cord of adult hens were studied after the intravenous administration of leptophos (30 mg/kg), tri-o-cresyl phosphate (TOCP 40 mg/kg) or dipterex (200 mg/kg). The level of NTE activity varied according to the regions of the central nervous system (CNS) of the control (normal) hen, being higher in the cerebrum (74.1 micromol of phenyl valerate hydrolyzed/10 minutes/mg protein) and in the cerebellum (68.7), and lower in the spinal cord (44.5 in cervical, 55.6 in thoracic and 50.0 in lumbar cord). Hens given leptophos and TOCP demonstrated delayed neuropathy with obvious inhibition of NTE, but the times of onset and the degrees of peak inhibition of NTE activity were different: 6-24 hours after dosing and 73-82% of normal activity for leptophos, and 24-48 hours and 45-80% for TOCP, respectively. Furthermore, the average inhibition of NTE during 6-48 hours after dosing, (called here 'period average inhibition') was also significantly different between the leptophos group (63-73%) and TOCP group (40-64%). Hens given dipterex did not demonstrate delayed neuropathy, and had the least peak inhibition and period average inhibition of NTE activity among the 3 groups. Ratios of NTE inhibition/AChE inhibition were higher in the leptophos group (0.91-1.24) and TOCP group (1.13-2.45) than in the dipterex group (0.25-0.79). These results indicate that the distribution of NTE in the soluble fraction of membrane proteins is different in different regions of the CNS, and that the degree of peak inhibition of NTE activity and the time of onset of peak inhibition induced by organophosphorus compounds (OPs) also differ for different OPs. Thus, practical and useful NTE measurements should identify the peak inhibition and period inhibition in several nervous tissue regions.
ESTHER : Tian_1998_Tohoku.J.Exp.Med_185_161
PubMedSearch : Tian_1998_Tohoku.J.Exp.Med_185_161
PubMedID: 9823777