Organophosphorous insecticides

Tasei, J.N. and Dinet, P. (1981). Effets compares de deux pyrethrinoides de synthdse et de trois insecticides organophosphores sur les megachiles Megachile rotundata F. = pacifica Pz.). Apidologie 12, 363-376. 

Moreover organophosphoric acid esters have found application as insecticides (e.g. Parathion). Some derivatives are highly toxic to man (e.g. Sarin, Soman). The organophosphonates act as inhibitors of the enzyme cholinesterase by phosphorylating it. This enzyme is involved in the proper function of the parasympathetic nervous system. A concentration of 5 x 10 g/L in the air can already cause strong toxic effects to man. 

Pewnim T, Seifert J. 1993. Structural requirements for altering the L-tryptophan metabolism in mice by organophosphorous and methylcarbamate insecticides. Eur J Pharmacol 248 237-241. 

The inhibition of brain cholinesterase is a biomarker assay for organophosphorous (OP) and carbamate insecticides (Chapter 10, Section 10.2.4). OPs inhibit the enzyme by forming covalent bonds with a serine residue at the active center. Inhibition is, at best, slowly reversible. The degree of toxic effect depends upon the extent of cholinesterase inhibition caused by one or more OP and/or carbamate insecticides. In the case of OPs administered to vertebrates, a typical scenario is as follows sublethal symptoms begin to appear at 40-50% inhibition of cholinesterase, lethal toxicity above 70% inhibition. 

The carbamate and OP insecticides and the organophosphorous nerve gases soman, sarin, and tabun all act as anticholinesterases, and most of their toxicity is attributed to this property. The naturally occurring carbamate physostigmine, which has been used in medicine, is also an anticholinesterase. Some OP compounds can cause relatively long-lasting inhibition of the enzyme because of the phenomenon of... 

Environmental Health Criteria 63 (1986). Organophosphorous Insecticides A General Introduction. Geneva WHO. 

Eto, M. (1974). Organophosphorous Insecticides Organic and Biological Chemistry. Cleveland, OH CRC Press. 

Faerman I.S. 0 funktsional nom sostoyanii pecheni i zheludka u lits, zanyatykh proizvod-stvom fosfororganicheskikh insektitsidov (On the Functional State of the Liver and Stomach in People Producing Organophosphorous Insecticides) // Terapevt. (Therapist) archives. 1965. Vol. 37. Issue 5. P. 51-54. 

V.B. Kandimalla and H.X. Ju, Binding of acetylcholinesterase to multiwall carbon nanotube-cross-linked chitosan composite for flow-injection amperometric detection of an organophosphorous insecticide. Chem. Eur. J. 12, 1074—1080 (2006). 

Seikai, T. 1982. Acute toxicity of organophosphorous insecticides on the developmental stages of eggs, larvae and juveniles of Japanese striped knifejaw Oplegnathus fasciatus. Bull. Japan. Soc. Sci. Fish. 48 599-603. 

Heudorf U, Butte W, Schulz C, Angerer J (2006) Reference values for metabolites of pyrethroid and organophosphorous insecticides in urine for human biomonitoring in environmental medicine. Int J Hyg Environmental Health 209 293-299... 

Dragan D, Carpov A. 1987. Microencapsulated organophosphorous insecticides. III. Some aspects on the volatilization of malathion and disulfoton from aqueous suspensions of microcapsules. Microencapsul 4 97-105. 

Osweiler GD, Carson TL, Buck WB, et al. 1985. Organophosphorous and carbamate insecticides. In Clinical and diagnostic veterinary toxicology. 3rd ed. Dubuque, IA Kendall/Hunt Publishing... 

Dichlorvos (9.50) is an insecticide of reportedly wide use, the metabolites of which in humans include dichloroethanol and dimethyl phosphate. Like paraoxon, dichlorvos is hydrolyzed by human serum. However, the enzyme activities hydrolyzing the two substrates were shown to differ by a number of criteria [114], Clearly large gaps remain in our understanding of the human metabolism of organophosphorus insecticides and other toxins. A bacterial phosphodiesterase appears as a promising tool to understand the catalytic mechanisms of organophosphoric acid triester detoxification [115-117],... 

Tsuda. T.. Kojima. M.. Harada, H., Nakajima, A., and Aoki, S. Acute toxicity, accumulation and excretion of organophosphorous insecticides and their oxidation products in killifish, Cbemospbere, 35(5) 939-949, 1997. 

Field transport of a persistent organochlorine (tetradifon) and a degradable organophosphorous (azinphosmethyl) insecticide was examined under dry and wet irrigation treatments followed by winter precipitation (Yaron et al. 1974). In the dry irrigation... 

Currently, there are a number of organophosphorous compounds used in everyday life and agriculture as insecticides. Many of them are lipid-soluble compounds that are quickly and completely absorbed in practically every way, including skin as well as respiratory and... 

Atropine is often used for colds for temporarily draining the nasopharynx. Atropine is also used in combination with other drugs as an antidote for poisonous anticholinesterase agents such as organophosphorous insecticides and neuroparalytic gases, hi such situations, atropine removes or balances toxicities that are a result of a high concentration of acetylcholine. 

Metrifonate is an organophosphorous compound that is effective only in the treatment of S. haematobium The active metabolite, dichlorvos, inactivates acetylcholinesterase and potentiates inhibitory cholinergic effects. The schistosomes are swept away from the bladder to the lungs and are trapped. Therapeutic doses produce no untoward side effects except for mild cholinergic symptoms. It is contraindicated in pregnancy, previous insecticide exposure, or with depolarizing neuromuscular blockers. Metrifonate is not available in the United States. 

Albuquerque EX, Pereira EFR, Aracava Y et al (2006) Effective countermeasure against poisoning by organophosphorous insecticides and nerve. PNAS 103 13220-13225... 

Contreras HR Bustos-ObregOn E (1996) Effect of an organophosphorate insecticide on the testis, epididymis and preimplantational development and pregnancy outcome in mice. Int J Dev Biol, Suppl 1 207S. 

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