Methods for Measuring Cholinesterase Activities in Human Blood

Reiner, Elsa; Simeon-Rudolf, Vera

doi:10.1016/b978-012088523-7/50015-6

Cited by 5 publications

(7 citation statements)

References 32 publications

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“…This lack of sensitivity, when a population baseline is used to detect inhibition, is partially due to the normal interindividual enzyme activity variation, which is about 15–25% for BChE and 10–18% for AChE, and the intraindividual variation over time, which ranges between 6 and 3–7%, respectively [ 42 ]. Hence, an individual ChE activity baseline is necessary [ 21 , 24 , 43 , 44 ].…”

Section: Discussionmentioning

confidence: 99%

“…The lower sensitivity of BChE inhibition as a biomarker of exposure to OPs and CAR can be explained by the higher turnover of this enzyme when compared to AChE, for which the recovery of the activity is limited by the production of new erythrocytes, which takes over 120 days [ 22 ]. Thus, AChE remains depressed for a longer period [ 43 , 44 ]. In this study, all 10 farmers with enzyme depletion rates higher the cut off levels were from Taquara.…”

Section: Discussionmentioning

confidence: 99%

“…However, this period is difficult to be reached in locations with ongoing work, such as the areas investigated in this study, where the farmers apply pesticides during the entire year. We were able to establish a 15-day non-exposure period, during which the baseline could not have been reached, mainly for AChE, an enzyme with a lower turnover when compared with BChE [ 44 ]. Hence, it is possible that in some cases our sampling protocol did not allow the detection of enzyme depletion after exposure.…”

Section: Discussionmentioning

confidence: 99%

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Knowledge, Attitudes, Practices and Biomonitoring of Farmers and Residents Exposed to Pesticides in Brazil

Pasiani

Torres

Silva

et al. 2012

IJERPH

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In this study, the knowledge, attitudes and practices regarding pesticide use and the levels of exposure of farmers and residents to organophosphorous and/or carbamates pesticides were evaluated in two rural settings in Brazil. A questionnaire was completed by 112 farm workers aged ≥18 years. Almost all farmers acknowledged that pesticides were potentially harmful to their health (87.5%); however, over half rarely (48.2%) or never (7.2%) used personal protective devices (PPDs). An association was found (p = 0.001) between the work regimen and the use of PPDs, with more frequent equipment use among hired laborers than those involved in family agriculture. A significant correlation (p = 0.027) was found between the reporting of adverse symptoms and the use of backpack sprayers. Mean AChE activities of farmers (n = 64) and residents (n = 18) during the exposure and non-exposure periods were significantly lower than their control groups. Mean BChE activities of farmers and residents were significantly lower than their controls during the exposure period. Among the 60 farmers that had blood samples collected in both the exposure and non-exposure (baseline) periods, 10 (16.7%) had AChE depletion of over 30% during the exposure period compared with the baseline level. Six residents living on the same farms also presented this depletion. AChE was over 30% higher than the baseline level for 19 farmers (31.7%), indicating a reboot effect. Special education programs are needed in these regions to promote the safe use of pesticides in the field to decrease the risks from exposure to pesticides for farmers, and from secondary exposure to these compounds for their families.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Knowledge, Attitudes, Practices and Biomonitoring of Farmers and Residents Exposed to Pesticides in Brazil

Pasiani

Torres

Silva

et al. 2012

IJERPH

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“…Unfortunately, none of the currently used oximes is sufficiently effective against all inhibitors and there is no single reactivator having the ability to reactivate inhibited enzyme regardless of the chemical structure of the inhibitor [7,8]. Commonly used reactivators are characterised by the presence of several structural features: functional oxime group, quaternary nitrogen atom and different length of linking chain between two pyridinium rings in the case of bispyridinium reactivators [9,10]. Pyridoxal oxime, a derivative of B 6 vitamin, meets some of these structural features and can be used for synthesis of compounds structurally similar to common antidotes.…”

Section: Introductionmentioning

confidence: 99%

Extensive Intramolecular and Intermolecular Interactions in Two Quaternary Salts of the Pyridoxal Oxime

et al. 2012

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Two derivatives of pyridoxal oxime (1) were prepared by quaternization of pyridoxal oxime with phenacyl bromide and 2-methoxyphenacyl bromide. The crystal structures of the 1-phenacyl-3-hydroxy-4-hydroxyiminomethyl-5-hydroxymethyl-2-methylpyridinium bromide (2) and the novel 3-hydroxy-4-hydroxyiminomethyl-5-hydroxymethyl-2-methyl-1-(2 0 -methoxyphenacyl) pyridinium bromide (3) have been determined by X-ray diffraction method. The conformation of these two pyridoxal oxime phenacyl derivatives is locked by numerous intramolecular hydrogen bonds. The O-HÁÁÁBr, C-HÁÁÁBr and C-HÁÁÁO hydrogen bonds in 2 and 3 form complex three-dimensional network. Supramolecular structure of 3 also contains C-HÁÁÁp and pÁÁÁp interactions which link neighbouring cations.

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“…However, ICD-467 was ineffective in reactivating AChE in the brain and was found to be toxic (Shih, 1993;Harris et al, 1990). Imidazolium oximes can reactivate tabun-inhibited AChE (an adduct which contains a P-N bond instead of a P-O bond), and some can reactivate both tabun-inhibited and somaninhibited AChE (RS150D, 70% reactivation of GA; Im2-2, 44% reactivation of GA; Im2-13, 20% reactivation of GA and 71% reactivation of GD; Kovarik et al, 2013;Reiner & Simeon-Rudolf, 2006;Primožič et al, 2004). None have been superior to the bispyridinium oximes in reactivating tabuninhibited AChE (TMB-4, 91% reactivation of GA; obidoxime, 88% reactivation of GA; Worek et al, 2012); however, TMB-4 is ineffective against GD (Inns & Leadbeater, 1983) and obidoxime is also a poor reactivator of GD-inhibited AChE (Worek et al, 1998).…”

Section: Discussionmentioning

confidence: 99%

A conformational change in the peripheral anionic site ofTorpedo californicaacetylcholinesterase induced by a bis-imidazolium oxime

Legler

Soojhawon

Millard

2015

Acta Cryst D Biol Crystallogr

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As part of ongoing efforts to design improved nerve agent antidotes, two X-ray crystal structures of Torpedo californica acetylcholinesterase (TcAChE) bound to the bis-pyridinium oxime, Ortho-7, or its experimental bis-imidazolium analogue, 2BIM-7, were determined. Bis-oximes contain two oxime groups connected by a hydrophobic linker. One oxime group of Ortho-7 binds at the entrance to the active-site gorge near Trp279, and the second binds at the bottom near Trp84 and Phe330. In the Ortho-7-TcAChE complex the oxime at the bottom of the gorge was directed towards the nucleophilic Ser200. In contrast, the oxime group of 2BIM-7 was rotated away from Ser200 and the oxime at the entrance induced a significant conformational change in the peripheral anionic site (PAS) residue Trp279. The conformational change alters the surface of the PAS and positions the imidazolium oxime of 2BIM-7 further from Ser200. The relatively weaker binding and poorer reactivation of VX-inhibited, tabun-inhibited or sarin-inhibited human acetylcholinesterase by 2BIM-7 compared with Ortho-7 may in part be owing to the unproductively bound states caught in crystallo. Overall, the reactivation efficiency of 2BIM-7 was comparable to that of 2-pyridine aldoxime methyl chloride (2-PAM), but unlike 2-PAM the bis-imidazolium oxime lacks a fixed charge, which may affect its membrane permeability.

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Methods for Measuring Cholinesterase Activities in Human Blood

Cited by 5 publications

References 32 publications

Knowledge, Attitudes, Practices and Biomonitoring of Farmers and Residents Exposed to Pesticides in Brazil

Knowledge, Attitudes, Practices and Biomonitoring of Farmers and Residents Exposed to Pesticides in Brazil

Extensive Intramolecular and Intermolecular Interactions in Two Quaternary Salts of the Pyridoxal Oxime

A conformational change in the peripheral anionic site ofTorpedo californicaacetylcholinesterase induced by a bis-imidazolium oxime

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