Organophosphorus compounds effect

Larsen K-0, Hand HK. 1982. Effect of exposure to organophosphorus compounds on S-cholinesterase in workers removing poisonous depots. Scand J Work Environ Health 8 222-226. 

The chemical shifts for P—F compounds have been reviewed.The compounds differ from most other organophosphorus compounds because Sp becomes more positive as the electronegativity of the atoms attached to phosphorus increases. The effect is at a maximum for P" compounds. They behave normally with regard to an increase in shielding with increase in co-ordination number and therefore the P" compounds are the least shielded. Thus the largest negative values (— 190 to — 250) are observed for compounds of the type YPFj. With the new value of Sp of + 80 for PFg, the variation of Sp with the number of fluorine atoms in P compounds is now shown to be fairly consistent. The value of Sp has also been reported for a series of aminohalogeno P compounds. -... 

Brothers CP. 1990. Evaluation of an interdigitated gate electrode field-effect transistor for detecting organophosphorus compounds. Wright-Patterson AFB, OH Air Force Institute of Technology. NTISNo. AD-A23 0-161. 

Organophosphate Ester Hydraulic Fluids. A number of studies have been conducted on organophosphate ester hydraulic fluids because of the well known neurotoxic effects caused by organophosphorus insecticides, organophosphorus nerve gases, and tri-ort/w-cresyl phosphate (TOCP). The following manifestations of acute exposure to organophosphorus compounds have been described ... 

Johnson MK, Barnes JM. 1970. Age and the sensitivity of chicks to the delayed neurotoxic effects on some organophosphorus compounds. Biochem Pharmacol 19 3045-3047. 

Peedicayil J, Ernest K, Thomas M, et al. 1991. The effect of organophosphorus compounds on serum pseudocholinesterase levels in a group of industrial workers. Hum Exp Toxicol 10 275-278. 

In contrast to the reactions of the cycloamyloses with esters of carboxylic acids and organophosphorus compounds, the rate of an organic reaction may, in some cases, be modified simply by inclusion of the reactant within the cycloamylose cavity. Noncovalent catalysis may be attributed to either (1) a microsolvent effect derived from the relatively apolar properties of the microscopic cycloamylose cavity or (2) a conformational effect derived from the geometrical requirements of the inclusion process. Kinetically, noncovalent catalysis may be characterized in the same way as covalent catalysis that is, /c2 once again represents the rate of all productive processes that occur within the inclusion complex, and Kd represents the equilibrium constant for dissociation of the complex. 

Gordon, J.J., R.H. Inns, M.K. Johnson, L. Leadbeater, M.P. Maidment, D.G. Upshall, G.H. Cooper, and R.L. Rickard. The Delayed Neuropathic Effects of Nerve Agents and Some Other Organophosphorus Compounds." Archives of Toxicology 52 (1983) 71-82. 

Uyeki 1981 Chen etal. 1982). Diazoxon, an oxygen analog of diazinon, did produce SCE at 304 mg/kg, but was 3 to 10 times less effective than oxygen analogues of other organophosphorus compounds screened (Nishio and Uyeki 1981). 

Insects have acquired resistance to organochlorine compounds, such as DDT and BHC, developed as agricultural and hygienic insecticides after World War II. This insect resistance was also acquired to subsequent organophosphorus compounds and carbamate insecticides. Photostable pyrethroids have been developed for outdoor use because pyrethroids were found to be effective against these resistant pests. As a matter of course, these pyrethroids are also effective against sanitary pests however, problems associated with safety and chemical residues indoors must be resolved. 

The toxicity of the P-halidc anhydrides, like that of phosphoroxychloride (POCl3) and of other organophosphorus compounds discussed earlier in this section, is due to their high efficiency as irreversible inactivators of acetylcholinesterase [157]. The main target organs for the lethal effects of these chemical weapons are the brain and diaphragm. As for the detoxification of the P-halide anhydrides, it can occur by a number of biochemical mechanisms, namely chemical hydrolysis, enzymatic hydrolysis, and binding to hydrolases such as carboxylesterases, cholinesterases, and albumin [68][158][159]. 

Irreversible inhibition in an organism usually results in a toxic effect. Examples of this type of inhibitor are the organophosphorus compounds that interfere with acetylcholinesterase (see Box 7.26). The organophosphorus derivative reacts with the enzyme in the normal way, but the phosphory-lated intermediate produced is resistant to normal hydrolysis and is not released from the enzyme. 

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