Cyhalothrine

The specialities of chromatographic behaviour of cypermethrin, permethrin, X-cyhalothrin, deltamethrin and fenvalerate were investigated in this work. Gas chromatographic determination was cai ry out with use of packed column with stationai y phase of different polarity (OV-101, OV-210 OV-17) and capillary and polycapillary columns with non-polai ic stationary phase. Chromatographic peak identification was realized with attraction GC-MS method. 

Gas ehromatography mass-mass aequisition was used for the pyrethroid determination. Pyrethroids investigated were Allethrin, Prallethrin, Tetramethrin, Bifenthrin, Phenothrin, X-Cyhalothrin, Permethrin, Cyfluthrin, Cypermethrin, Flueythrinate, Fsfenvalerate, Fluvalinate and Deltamethrin. Piperonyl butoxide, main synergist eompound for pyrethroid eompounds, was also studied. 

Pilling, E.D., Bromley-ChaUenor, K.A.C., and Walker, C.H. et al. (1995). Mechanism of synergism between the pyrethroid insecticide lambda cyhalothrin and the imidazole fungicide prochloraz in the honeybee. Pesticide Biochemistry and Physiology 51, 1-11. 

In an extension to the studies mentioned above, the actions of 11 commercial pyrethroids on calcium influx and glutamate release were assessed using a high-throughput approach with rat brain synaptosomes [75, 76]. Concentration-dependent response curves for each commercial pyrethroid were determined and the data used in a cluster analysis. Previously characterized Type II pyrethroids that induce the CS-syndrome symptoms (cypermethrin, deltamethrin, and esfenvalerate) increased calcium influx and glutamate release, and clustered with two other ot-cyano pyrethroids (p-cyfluthrin and A-cyhalothrin) that shared these same actions. Previously characterized Type I pyrethroids (bioallethrin, cismethrin, and fenpropathrin) did not share these actions and clustered with two other non-cyano pyrethroids (tefluthrin and bifenthrin) that likewise did not elicit these actions. 

The effect of allethrin (a Type I pyrethroid), cyhalothrin, and deltamethrin (Type II pyrethroids) on neurotransmitter release from the hippocampus (acetylcholine, glutamate, and GABA release) and striatum (dopamine release) has recently been investigated using ex vivo microdialysis in freely moving rats exhibiting the symptoms of pyrethroid poisoning [94-97]. Deltamethrin increased the release... 

Hossain MM, Suzuki T, Sato I, Takewaki T, Suzuki K, Kobayashi H (2005) Neuromechanical effects of pyrethroids, allethrin, cyhalothrin and deltamethrin on the cholinergic processes in rat brain. Life Sci 77 795-807... 

DNT studies on six pyrethroids (bifenthrin, cyfluthrin, cyhalothrin, cypermethrin, fenpropathrin, and deltamethrin) were carried out in accordance with... 

Lambda-cyhalothrin and an isomer gamma-cyhalothrin not likely to be carcinogenic to humans [72]. 

X-Cyhalothrin hCEl, hCE2 Activated hPXR (6.3X), rPXR (> 3X) [29]... 

Studies with lambda-cyhalothrin and the freshwater crustacean G. pulex have shown that shorter durations of exposure result in substantially less severe effects than maintained, long-term exposures [15], In this case there was a significant reduction in toxicity with decreasing exposure times, with an 18-fold reduction in toxicity with exposure for 1 h compared to that determined after exposure for 96 h. Given this inverse correlation with exposure duration and toxicity, effects under natural environmental conditions where water column concentrations of pyrethroids are expected to decrease relatively rapidly are again likely to be less than would be predicted from estimates of toxicity under standard laboratory conditions with maintained concentrations (see Sect. 5). 

The field nontarget arthropod data for pyrethroids summarized in Table 9 indicate that for all pyrethroids there was an initial reduction in abundance for some species shortly after application. There was a trend of more marked effects at the higher full field application rates with less marked affects at the lower drift rates tested (e.g., Deltamethrin, bifenthrin, and esfenvalerate). Also there was a trend of greater selectivity (i.e., fewer taxa affected) at lower drift rates (e.g., /amMa-cyhalothrin and Deltamethrin). For nearly all the pyrethroid field studies, either full or partial recovery of affected taxa was reported by the end of the field study or growing season, and in some cases for certain taxa, recovery occurred within 1-3 weeks. 

Lambda- cyhalothrin Autumn Cereals 5 g a.i./ha Mean depression in abundance of affected species was 20-60% And lasted 4-5 weeks Recovery after 4-5 weeks... 

Day KE (1991) Effects of dissolved organic carbon on accumulation and acute toxicity of fenvalerate, Deltamethrin and cyhalothrin to Daphnia magna (Straus). Environ Toxicol Chem 10 91-101... 

Hand LH, Kuet SF, Fane MCG et al (2001) Influences of aquatic plants on the fate of the pyrethroid insecticide /amMti-cyhalothrin in aquatic environments. Environ Toxicol Chem 20 1740-1745... 

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