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Organophosphate oxons

The reasons for negative and positive results seem evTHent. Negative results appear linked with legal or extended field reentry and low oxon metabolites. Positive results appear linked with early field reentry and/or the presence of unexpected levels of organophosphate oxon metabolites. [Pg.65]

Oxon metabolites. The organophosphate oxons have been a major factor in (0-120 days) worker reentry incidents 2, 3). [Pg.67]

Table X shows a comparison between the ultraviolet spectral maxima obtained in this study and the literature values. The standard and collected GLC spectra are qualitatively the same. The characteristic shift to lower wavelength by an organophosphate oxon is evident. The shift to a lower wavelength when a phosphate ester replaces the H atom of the hydrolysis product is noted also (Diazinon). Table X shows a comparison between the ultraviolet spectral maxima obtained in this study and the literature values. The standard and collected GLC spectra are qualitatively the same. The characteristic shift to lower wavelength by an organophosphate oxon is evident. The shift to a lower wavelength when a phosphate ester replaces the H atom of the hydrolysis product is noted also (Diazinon).
Sultatos, L.G. and S.D. Murphy. 1983. Hepatic microsomal detoxification of the organophosphates paraoxon and chlorpyrifos oxon in the mouse. Drug Metabol. Dispos. 11 232-238. [Pg.906]

Suffet, I.H., Faust. S.D., and Carey, W.F. Gas-liquid chromatographic separation of some organophosphate pesticides, then-hydrolysis products, and oxons. Environ. Sci. Technoi, l(8) 639-643, 1967. [Pg.1730]

Four primary factors apparently lead to an incident 5 or more days after application a dusty work environment, use of a sufficiently toxic organophosphate, conversion of the parent compound to its oxon metabolite, and dry conditions. The dusty working environment has been recognized since 1952 as a key element for transferring pesticides from leaf, fruit, and soil surfaces to a field laborer (] ). The type of dust, i.e. soil type, also influences the rate of conversion of an organophosphate to its more toxic oxon form (2). And dry conditions are necessary for the persistence of these oxon residues over long periods of time 3). [Pg.67]

Wang and coworkers [24] described NCE with a thick film amperometric detector for separation and detection of organophosphate nerve agents (para-oxon, methyl parathion, fenitrothion, and ethyl parathion) within 140 seconds. The electropherograms are shown in Fig. 8.29 indicating good separation. The separation conditions were buffer, 20 mM MES (pH 5.0) containing 7.5 mM... [Pg.228]

The inhibition by other organophosphate compounds of the carboxylesterase which hydrolyzes malathion is a further example of xenobiotic interaction resulting from irreversible inhibition because, in this case, the enzyme is phosphorylated by the inhibitor. A second type of inhibition involving organophosphorus insecticides involves those containing the P=S moiety. During CYP activation to the esterase-inhibiting oxon, reactive sulfur is released that inhibits CYP isoforms by an irreversible interaction with the heme iron. As a result, these chemicals are inhibitors of the metabolism of other xenobiotics, such as carbaryl and fipronil, and are potent inhibitors of the metabolism of steroid hormones such as testosterone and estradiol. [Pg.200]

Other organophosphates that have been examined in fish include parathion and methyl-parathion39. The oxons of parathion and methyl-parathion were not affected by hepatic A esterases in mosquitofish6. Methyl-parathion and methyl-parathion oxon were detoxified by glutathione in sunfish hepatic homogenates, but parathion and paraoxon were not affected by glutathione4. [Pg.177]

The -thion organophosphates (those containing the P=S bond) are activated, not inactivated, by conversion to -oxon (P=0) derivatives. They are less stable than halogenated hydrocarbon insecticides of the DDT type therefore, they are less persistent in the environment Parathion is more toxic than malathion. It is very lipid-soluble and rapidly absorbed through the lungs and skin. The answer is (E). [Pg.66]

FIG. 2, Schematic illustrating the interaction of acetj Icholine (I), the carbamate carbaryl (II), and the organophosphate ehiorpynfos-oxon (IJI) with the active site of acetylcholinesterase (ACbE). The general rate of bound AChE hydrolysis is ACh > > carbaryl > chlorpyrifos-oxon. [Pg.105]

The difficulties and problems of LLE of pesticides from water have been outlined. A theoretical approach for accurate and precise quantitation of pesticides from natural water using p-values has been proposed. Few p-values have been reported for aqueous solvent systems some have been determined for organophosphate pesticides (35). Table VI shows the p-value for the parathion system consisting of parathion, its oxon, and hydrolysis product, p-nitrophenol extracted under the conditions of 0.2M phosphate buffer and a pH of 3.10. At this pH value these compounds hydrolyze least. Ether is the best solvent for the LLE of the whole system. Equations 10, 11, 12, and 13 are now used to determine... [Pg.23]

Seventeen organophosphate pesticides (e.g., famphur and famphur oxon, para-oxon, fenthoxon, ronnel, 3-chloro-4-methyl-7-hydroxycoumarin, stitofos, parathion, coumaphos) were extracted from beef tissues and baseline resolved on a C g colunm (photodiode array detector, A = 190-350 nm). A complex 34-min 55/45 - 70/30 acetonitrile/water gradient was used [957]. Excellent peak shapes were obtained. A... [Pg.355]

There is evidence that organophosphates may play a role in disrupting glial cell growth. It has been demonstrated that chlorpyrifos, chlorpyrifos-oxon and diazinon inhibit DNA synthesis in nerve cells, in vitro (18). Tlie effects were more pronounced in glial cells (C6) than in neuronal cells (Cl2). The disruption of DNA synthesis could, in turn, result in altered glial cell structure, with consequent changes in the properties of the blood-brain-barrier. However,... [Pg.152]

Rodrigues (1999) described the multiplication of Ymax> in terms of pmol min pmol CYP by the mean specific content of the corresponding CYP in native liver microsomes as the normalized rate (NR) in pmol min mg of microsomal protein. The normalized rate for each CYP is totaled to give total normalized rate (TNR). Each NR may be expressed as a percent of the TNR (% TNR). Foxenberg et al. (2011), using the values obtained from human rCYPs, expressed the total amount of parent OPs (organophosphate pesticides viz., chlorpyrifos or parathion) metabolized in liver to its oxon or dearylated form (TCPy or PNP), respectively as ... [Pg.72]

Kaliste-Korhonen, E., Tuovinen, K., Hanninen, O., 1996. Interspecies differences in enzymes reacting with organophosphates and their inhibition by para-oxon in vitro. Hum. Exp. Toxicol. 15, 972-978. [Pg.893]


See other pages where Organophosphate oxons is mentioned: [Pg.37]    [Pg.102]    [Pg.102]    [Pg.67]    [Pg.63]    [Pg.64]    [Pg.291]    [Pg.12]    [Pg.71]    [Pg.198]    [Pg.213]    [Pg.751]    [Pg.802]    [Pg.52]    [Pg.176]    [Pg.231]    [Pg.106]    [Pg.303]    [Pg.304]    [Pg.305]    [Pg.154]    [Pg.292]    [Pg.601]    [Pg.18]    [Pg.153]    [Pg.887]    [Pg.240]   
See also in sourсe #XX -- [ Pg.67 ]




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Oxonation

Oxone

Oxons

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