The history of pyridinium oximes as nerve gas antidotes: the British contribution.

PubMed

Petroianu, G A

2013-11-01

Irwin B. Wilson, working in the laboratory of David Nachmansohn at Columbia, demonstrated the ability of hydroxylamine to reactivate cholinesterase inhibited by organophosphates. Soon thereafter Wilson and Ginsburg reacted pyridine-2-aldoxime with methyl iodide to synthesize the first pyridinium aldoxime reactivator of clinical relevance, 2-PAM (pralidoxime). Independently, and at the same time, similar work was conducted in Britain at the Chemical Defence Experimental Establishment in Porton by Green leading also to the synthesis of 2-PAM and the recognition of its reactivating properties. While the American contribution is well known, the British achievements were less publicized. The present contribution attempts to shed some light on the life and work of the people who contributed to the early development of cholinesterase reactivators, the pyridinium aldoximes at Porton.

Unequal Efficacy of Pyridinium Oximes in Acute Organophosphate Poisoning

PubMed Central

Antonijevic, Biljana; Stojiljkovic, Milos P.

2007-01-01

The use of organophosphorus pesticides results in toxicity risk to non-target organisms. Organophosphorus compounds share a common mode of action, exerting their toxic effects primarily via acetylcholinesterase (AChE) inhibition. Consequently, acetylcholine accumulates in the synaptic clefts of muscles and nerves, leading to overstimulation of cholinergic receptors. Acute cholinergic crisis immediately follows exposure to organophosphate and includes signs and symptoms resulting from hyperstimulation of central and peripheral muscarinic and nicotinic receptors. The current view of the treatment of organophosphate poisoning includes three strategies, i.e. the use of an anticholinergic drug (e.g., atropine), cholinesterase-reactivating agents (e.g., oximes) and anticonvulsant drugs (e.g., benzodiazepines). Oximes, as a part of antidotal therapy, ensure the recovery of phosphylated enzymes via a process denoted as reactivation of inhibited AChE. However, both experimental results and clinical findings have demonstrated that different oximes are not equally effective against poisonings caused by structurally different organophosphorus compounds. Therefore, antidotal characteristics of conventionally used oximes can be evaluated regarding how close the certain substance is to the theoretical concept of the universal oxime. Pralidoxime (PAM-2), trimedoxime (TMB-4), obidoxime (LüH-6), HI-6 and HLö-7 have all been demonstrated to be very effective in experimental poisonings with sarin and VX. TMB-4 and LüH-6 may reactivate tabun-inhibited AChE, whereas HI-6 possesses the ability to reactivate the soman-inhibited enzyme. An oxime HLö-7 seems to be an efficient reactivator of AChE inhibited by any of the four organophosphorus warfare agents. According to the available literature, the oximes LüH-6 and TMB-4, although relatively toxic, are the most potent to induce reactivation of AChE inhibited by the majority of organophosphorus pesticides. Since there are no reports of controlled clinical trials on the use of TMB-4 in human organophosphate pesticide poisoning, LüH-6 may be a better option. PMID:17456837

An easy method for the determination of active concentrations of cholinesterase reactivators in blood samples: Application to the efficacy assessment of non quaternary reactivators compared to HI-6 and pralidoxime in VX-poisoned mice.

PubMed

Calas, André-Guilhem; Dias, José; Rousseau, Catherine; Arboléas, Mélanie; Touvrey-Loiodice, Mélanie; Mercey, Guillaume; Jean, Ludovic; Renard, Pierre-Yves; Nachon, Florian

2017-04-01

Organophosphorus nerve agents, like VX, are highly toxic due to their strong inhibition potency against acetylcholinesterase (AChE). AChE inhibited by VX can be reactivated using powerful nucleophilic molecules, most commonly oximes, which are one major component of the emergency treatment in case of nerve agent intoxication. We present here a comparative in vivo study on Swiss mice of four reactivators: HI-6, pralidoxime and two uncharged derivatives of 3-hydroxy-2-pyridinaldoxime that should more easily cross the blood-brain barrier and display a significant central nervous system activity. The reactivability kinetic profile of the oximes is established following intraperitoneal injection in healthy mice, using an original and fast enzymatic method based on the reactivation potential of oxime-containing plasma samples. HI-6 displays the highest reactivation potential whatever the conditions, followed by pralidoxime and the two non quaternary reactivators at the dose of 50 mg/kg bw. But these three last reactivators display equivalent reactivation potential at the same dose of 100 μmol/kg bw. Maximal reactivation potential closely correlates to surviving test results of VX intoxicated mice. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Cholinesterase Structure: Identification of Mechanisms and Residues Involved in Organophosphate Inhibition and Enzyme Reactivation

DTIC Science & Technology

2005-05-01

nerve agents , soman is the great- terrorist acts. At the same time, OP pesticides , such as est challenge since both the rapid aging of the soman- paraoxon...also from enzyme very slowly (requiring hours, days, or weeks used as nerve warfare agents . Similar to pesticides , nerve for complete dissociation...TERMS acetylcholinesterase, nerve agent antidotes and propylaxis, organophosphate scavenging , oxime reactivation fluorescence spectroscopy, exposure

Oximes of αω-diquaternary alkane salts as antidotes to organophosphate anticholinesterases

PubMed Central

Berry, W. K.; Davies, D. R.; Green, A. L.

1959-01-01

Sixteen compounds of the general structure {HON: CH.C5H4N+.[CH2]n.R+}2Br- have been synthesized in which the position of the oxime group in the pyridine ring, the second charged group R+ and the number of methylene groups between the charged atoms have been varied. The rate at which these compounds reactivate cholinesterase inhibited by ethyl pyrophosphate has been studied and a number have been found which are more active than 2-hydroxyiminomethyl-N-methylpyridinium methanesulphonate. Since considerable variation in structure was found among those compounds which are better reactivators than the latter, the concept that 2-hydroxyiminomethyl-N-methylpyridinium salts are unique in their ability to fit the surface of the inhibited enzyme is no longer tenable. The reactivating power of these oximes correlated well with their ability, when given in conjunction with atropine, to save the lives of mice poisoned by ethyl pyrophosphate. The most effective compounds, NN'-trimethylenebis-(4-hydroxyiminomethylpyridinium bromide) and NN'-hexamethylenebis(2-hydroxyiminomethylpyridinium bromide), contained a further oxime group in R+, but the second oxime group was not essential for high activity. These new oximes were also superior in saving the lives of mice poisoned with sarin (isopropyl methylphosphonofluoridate), but the improvement was not as dramatic as when the mice were poisoned with ethyl pyrophosphate. The toxicity of the compounds varied with both n and R+ and was unrelated to the therapeutic potency. PMID:13662572

Development and Structural Modifications of Cholinesterase Reactivators against Chemical Warfare Agents in Last Decade: A Review.

PubMed

Sharma, Rahul; Gupta, Bhanushree; Singh, Namrata; Acharya, J R; Musilek, Kamil; Kuca, Kamil; Ghosh, Kallol Kumar

2015-01-01

Organophosphate (OP) pesticides and nerve agents are responsible for suicidal and accidental poisonings. The acute toxicity of nerve agents leads to progressive inhibition of the enzyme acetylcholinesterase (AChE) by phosphylation of serine residue at the active site of gorge. The recent massive destruction of Syrian civilians by nerve gas sarin, has again renewed the research attention of global science fraternity towards nerve agents, their mode of action and most prominently their therapeutic treatment. This review is principally focused on nerve agent intoxication. The common approach to deal with OP-intoxication is, application of antimuscarinic drug (atropine), anticonvulsant drug (diazepam) and clinically used oximes (pralidoxime, trimedoxime, obidoxime and asoxime). However, the existing therapeutic approach is arguable and has several failings to cure all kinds of nerve agent poisonings. Considering this issue, numerous oximes have been synthesized and screened through various in-vitro and in-vivo studies in last decade to overcome the downsides. At present, only a few oximes (bis pyridinum-oximes) exhibit sound efficacy against selective OPs. In spite of extensive efforts, till date no oxime is available as a universal antidote against all the classes of OPs. This review is centered on the recent developments and structural modification of AChE reactivators against nerve agent toxicity. In particular, a deeper look has been taken into chemical modifications of the reactivators by incorporation of different structural moieties targeted towards the increased reactivation affinity and improved blood brain barrier (BBB) penetration.

Bisquaternary pyridinium oximes: Comparison of in-vitro reactivation potency of compounds bearing aliphatic linkers and heteroaromatic linkers for paraoxon-inhibited electric eel and recombinant human acetylcholinesterase

PubMed Central

Bharate, Sandip B.; Guo, Lilu; Reeves, Tony E.; Cerasoli, Douglas M.; Thompson, Charles M.

2009-01-01

Oxime reactivators are the drugs of choice for the post-treatment of OP (organophosphorus) intoxication and used widely for mechanistic and kinetic studies of OP-inhibited cholinesterases. The purpose of the present study was to evaluate new oxime compounds to reactivate acetylcholinesterase (AChE) inhibited by the OP paraoxon. Several new bisquaternary pyridinium oximes with heterocyclic linkers along with some known bisquaternary pyridinium oximes bearing aliphatic linkers were synthesized and evaluated for their in vitro reactivation potency against paraoxon-inhibited electric eel acetylcholinesterase (EeAChE) and recombinant human acetylcholinesterase (rHuAChE). Results herein indicate that most of the compounds are better reactivators of EeAChE than of rHuAChE. The reactivation potency of two different classes of compounds with varying linker chains was compared and observed that the structure of the connecting chain is an important factor for the activity of the reactivators. At a higher concentration (10−3 M), compounds bearing aliphatic linker showed better reactivation than compounds with heterocyclic linkers. Interestingly, oximes with a heterocyclic linker inhibited AChE at higher concentration (10−3 M), whereas their ability to reactivate was increased at lower concentrations (10−4 M and 10−5 M). Compounds bearing either a thiophene linker 26, 46 or a furan linker 31 showed 59%, 49% and 52% reactivation of EeAChE, respectively, at 10−5 M. These compounds showed 14%, 6% and 15% reactivation of rHuAChE at 10−4 M. Amongst newly synthesized analogs with heterocyclic linkers (26–35 and 45–46), compound 31, bearing furan linker chain, was found to be the most effective reactivator with a kr 0.042 min−1, which is better than obidoxime (3) for paraoxon-inhibited EeAChE. Compound 31 showed a kr 0.0041 min−1 that is near equal to pralidoxime (1) for paraoxon-inhibited rHuAChE. PMID:20005727

Planarian cholinesterase: in vitro characterization of an evolutionarily ancient enzyme to study organophosphorus pesticide toxicity and reactivation.

PubMed

Hagstrom, Danielle; Hirokawa, Hideto; Zhang, Limin; Radic, Zoran; Taylor, Palmer; Collins, Eva-Maria S

2017-08-01

The freshwater planarian Dugesia japonica has recently emerged as an animal model for developmental neurotoxicology and found to be sensitive to organophosphorus (OP) pesticides. While previous activity staining of D. japonica, which possess a discrete cholinergic nervous system, has shown acylthiocholine catalysis, it is unknown whether this is accomplished through an acetylcholinesterase (AChE), butyrylcholinesterase (BChE), or a hybrid esterase and how OP exposure affects esterase activity. Here, we show that the majority of D. japonica cholinesterase (DjChE) activity departs from conventional AChE and BChE classifications. Inhibition by classic protonable amine and quaternary reversible inhibitors (ethopropazine, donepezil, tacrine, edrophonium, BW284c51, propidium) shows that DjChE is far less sensitive to these inhibitors than human AChE, suggesting discrete differences in active center and peripheral site recognition and structures. Additionally, we find that different OPs (chlorpyrifos oxon, paraoxon, dichlorvos, diazinon oxon, malaoxon) and carbamylating agents (carbaryl, neostigmine, physostigmine, pyridostigmine) differentially inhibit DjChE activity in vitro. DjChE was most sensitive to diazinon oxon and neostigmine and least sensitive to malaoxon and carbaryl. Diazinon oxon-inhibited DjChE could be reactivated by the quaternary oxime, pralidoxime (2-PAM), and the zwitterionic oxime, RS194B, with RS194B being significantly more potent. Sodium fluoride (NaF) reactivates OP-DjChE faster than 2-PAM. As one of the most ancient true cholinesterases, DjChE provides insight into the evolution of a hybrid enzyme before the separation into distinct AChE and BChE enzymes found in higher vertebrates. The sensitivity of DjChE to OPs and capacity for reactivation validate the use of planarians for OP toxicology studies.

Pro-2-PAM Therapy for Central and Peripheral Cholinesterases

PubMed Central

DeMar, James C.; Clarkson, Edward D.; Ratcliffe, Ruthie H.; Campbell, Amy J.; Thangavelu, Sonia G.; Herdman, Christine A.; Leader, Haim; Schulz, Susan M.; Marek, Elizabeth; Medynets, Marie A.; Ku, Theresa C.; Evans, Sarah A.; Khan, Farhat A.; Owens, Roberta R.; Nambiar, Madhusoodana P.; Gordon, Richard K.

2010-01-01

Novel therapeutics to overcome the toxic effects of organophosphorus (OP) chemical agents are needed due to the documented use of OPs in warfare (e.g. 1980–1988 Iran/Iraq war) and terrorism (e.g. 1995 Tokyo subway attacks). Standard OP exposure therapy in the United States consists of atropine sulfate (to block muscarinic receptors), the acetylcholinesterase (AChE) reactivator (oxime) pralidoxime chloride (2-PAM), and a benzodiazepine anticonvulsant to ameliorate seizures. A major disadvantage is that quaternary nitrogen charged oximes, including 2-PAM, do not cross the blood brain barrier (BBB) to treat brain AChE. Therefore, we have synthesized and evaluated pro-2-PAM (a lipid permeable 2-PAM derivative) that can enter the brain and reactivate CNS AChE, preventing seizures in guinea pigs after exposure to OPs. The protective effects of the pro-2-PAM after OP exposure were shown using a) surgically-implanted radiotelemetry probes for electroencephalogram (EEG) b) neurohistopathology of brain, c) cholinesterase activities in the PNS and CNS, and d) survivability. The PNS oxime 2-PAM was ineffective at reducing seizures/status epilepticus (SE) in diisopropyl-fluorophosphate (DFP)-exposed animals. In contrast, pro-2-PAM significantly suppressed and then eliminated seizure activity. In OP-exposed guinea pigs, there was a significant reduction in neurological damage with pro-2-PAM, but not 2-PAM. Distinct regional areas of the brains showed significantly higher AChE activity 1.5 h after OP exposure in pro-2-PAM treated animals compared to the 2-PAM treated ones. However, blood and diaphragm showed similar AChE activities in animals treated with either oxime, as both 2-PAM and pro 2-PAM are PNS active oximes. In conclusion, pro-2-PAM can cross the BBB, is rapidly metabolized inside the brain to 2-PAM, and protects against OP-induced SE through restoration of brain AChE activity. Pro-2-PAM represents the first non-invasive means of administering a CNS therapeutic for the deleterious effects of OP poisoning by reactivating CNS AChE. PMID:20156430

In vitro investigation of efficacy of new reactivators on OPC inhibited rat brain acetylcholinesterase.

PubMed

Atanasov, Vasil N; Petrova, Iskra; Dishovsky, Christophor

2013-03-25

Organophosphorus compounds (OPC) were developed as warfare nerve agents. They are also widely used as pesticides. The drug therapy of intoxication with OPC includes mainly combination of cholinesterase (ChE) reactivators and cholinolytics. There is no single ChE reactivator having an ability to reactivate sufficiently the inhibited enzyme due to the high variability of chemical structure of the inhibitors. The difficulties in reactivation of ChE activity and slight antidote effect regarding intoxication with some OPC are some of the reasons for continuous efforts to obtain new reactivators of ChE. The aim of the present study was to evaluate the efficacy of some ChE reactivators against OPC intoxication (tabun, paraoxon and dichlorvos) in in vitro experiments and to compare their activity to that known for some currently used oximes (obidoxime, HI-6, 2-PAM). Experiments were carried out using rat brain acetylcholinesterase (AChE). Reactivators showed different activity in the reactivation of rat brain AChE after dichlorvos, paraoxon and tabun inhibition. AChE was easier reactivated after paraoxon treatment. The best effect showed BT-07-4M, obidoxime, TMB-4 and BT-08 from the group of symmetric oximes, and Toxidin, BT-05 and BT-03 from asymmetric compounds. The reactivation of brain AChE inhibited with tabun demonstrated better activity of new compound BT-07-4M, TMB-4 and obidoxime from symmetric oximes, and BT-05 and BT-03 possessing asymmetric structure. All compounds showed low activity toward inhibition of AChE caused by dichlorvos. Comparison of two main structure types (symmetric/asymmetric) showed that the symmetric compounds reactivated better AChE, inhibited with this OPC, than asymmetric ones. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Measurement of K-27, an oxime-type cholinesterase reactivator by high-performance liquid chromatography with electrochemical detection from different biological samples.

PubMed

Gyenge, Melinda; Kalász, Huba; Petroianu, George A; Laufer, Rudolf; Kuca, Kamil; Tekes, Kornélia

2007-08-17

K-27 is a bisquaternary asymmetric pyridinium aldoxime-type cholinesterase reactivator of use in the treatment of poisoning with organophosphorous esterase inhibitors. A sensitive, simple and reliable reverse-phase high-performance liquid chromatographic method with electrochemical detection was developed for the measurement of K-27 concentrations in rat brain, cerebrospinal fluid, serum and urine samples. Male Wistar rats were treated intramuscularly with K-27 and the samples were collected 60 min later. Separation was carried out on an octadecyl silica stationary phase and a disodium phosphate solution (pH 3.7) containing citric acid, octane sulphonic acid and acetonitrile served as mobile phase. Measurements were carried out at 30 degrees C at E(ox) 0.65 V. The calibration curve was linear through the range of 10-250 ng/mL. Accuracy, precision and the limit of detection calculated were satisfactory according to internationally accepted criteria. Limit of quantitation was 10 ng/mL. The method developed is reliable and sensitive enough for monitoring K-27 levels from different biological samples including as little as 10 microL of cerebrospinal fluid. The method--with slight modification in the composition of the mobile phase--can be used to measure a wide range of other related pyridinium aldoxime-type cholinesterase reactivators.

Chromatographic analysis of toxic phosphylated oximes (POX): a brief overview.

PubMed

Becker, Christian; Worek, Franz; John, Harald

2010-10-01

Poisoning with organophosphorus compounds (OP), e.g. pesticides and nerve agents, causes inhibition of acetylcholinesterase (AChE) by phosphylation of the active site serine residue. Consequently, accumulation of stimulating acetylcholine in the synaptic cleft induces cholinergic crisis which ultimately may lead to death. For standard causal therapy, enzyme reactivators are administered representing oxime derivatives of quarternary pyridinium compounds, e.g. pralidoxime (2-PAM), obidoxime and HI 6. The mechanism of action includes removal of the phosphyl moiety by a nucleophilic attack of the oximate molecule substituting the enzyme and forming a phosphylated oxime (POX). POX is produced in stoichiometric amounts of reactivated enzyme and exhibits a significantly enhanced toxicity (inhibition rate constant) when compared to the parent OP. However, stability of POX under physiological conditions appears to be highly limited. Nevertheless, the presence of POX reveals a potential critical issue for both therapeutic efficacy in vivo and pharmacokinetic and pharmacodynamic (PK-PD) modelling based on cholinesterase activity data. Detailed characterization represents an important need for elaboration of the entire oxime pharmacology.Nevertheless, reports on POX toxicity and analysis are quite rare and may therefore be indicative of the challenge of POX analysis. This review provides a concise overview of chromatographic approaches applied to POX separation. Chromatography represents the key technology for POX purification and quantification in kinetic in vitro studies using buffers and biological fluids. Applications based on reversed-phase chromatography (RPC), ion pair chromatography (IPC) and an affinity approach as well as thin layer chromatography (TLC) are discussed and novel applications and data are presented. Copyright © 2010 John Wiley & Sons, Ltd.

One Hundred Eighty Day Subchronic Oral Toxicity Study of Pyridostigmine Bromide in Rats. Volume 1

DTIC Science & Technology

1990-06-01

has proposed a treatment regimen incorporating prophylaxis with a reversible cholinesterase inhibitor and, following nerve agent exposure, antidotal...would accomplish two goals: the oxime would abate the inhibition induced by the reversible cholinesterase inhibitor prophylaxis, and the atropine will...cholinesterase inhibitor as the pretreatment component of a therapeutic regimen that would include antidotal therapy with 2-PAM chloride and atropine. A

Immobilization of Russian VX skin depots by localized cooling: implications for decontamination and medical countermeasures.

PubMed

Mikler, J; Tenn, C; Worek, F; Reiter, G; Thiermann, H; Garrett, M; Bohnert, S; Sawyer, T W

2011-09-25

The chemical weapon nerve agent known as Russian VX (VR) is a potent organophosphorus (OP) compound that is much less studied than its VX analogue with respect to toxicity, as well as to the effectiveness of several known countermeasures against it. An anaesthetized domestic swine model was utilized to assess several approaches in mitigating its toxicity, including the utility of cooling VR treated skin to increase the therapeutic window for treatment. The 6h LD₅₀ for VR topically applied on the ear was 100 μg/kg. Treatment of VR exposed animals (5 × LD₅₀) with pralidoxime (2PAM) very poorly regenerated inhibited blood cholinesterase activity, but was partially effective in preventing signs of OP poisoning and increasing survival. In contrast, treatment with the Hagedorn oxime HI-6 reactivated cholinesterase, eliminated all signs of poisoning and prevented death. Decontamination with the Reactive Skin Decontaminant Lotion (RSDL) 15 min after VR exposure was completely effective in preventing death. Cooling of the VR exposure sites for 2 or 6h prevented signs of OP poisoning and death during the cooling period. However, these animals died very quickly after the cessation of cooling, unless they were treated with oxime or decontaminated with RSDL. Blood analyses showed that cooling of agent exposure sites delayed the entry of VR into the bloodstream. Medical treatment with HI-6 and to a lesser extent 2PAM, or decontamination with RSDL are effective in protecting against the toxic effects of cutaneous exposure to VR. Immobilizing this agent (and related compounds) within the dermal reservoir by cooling the exposure sites, dramatically increases the therapeutic window in which these medical countermeasures are effective. Crown Copyright © 2011. Published by Elsevier Ireland Ltd. All rights reserved.

In vitro and in vivo genotoxicity assessment of HI-6 dimethanesulfonate/oxime.

PubMed

Nakab, Lauren; Bardot, Isabelle; Bardot, Sébastien; Simar, Sophie; Marzin, Daniel; Nesslany, Fabrice

2014-03-01

Organophosphate compounds, which induce organophosphate poisoning, were originally used as pesticides. But this type of product has also been used as warfare nerve agent like sarin, soman, Russian VX, or tabun. HI-6-dimethanesulfonate is a salt of the oxime HI-6 used in the treatment of nerve-agent poisoning. It is known to be the best re-activator component of inactivated acetyl cholinesterase. HI-6-dimethanesulfonate has shown a higher level of solubility with similar potency to reactivate acetyl cholinesterase and a similar pharmacokinetics profile compared with HI-6 dichloride. HI-6 dimethanesulfonate was tested for its mutagenic and genotoxic potential by use of the standard ICH S2R (1) battery for the evaluation of pharmaceuticals. HI-6-dimethanesulfonate was mutagenic in the Ames test only in the presence of metabolic activation. In the mutation assay at the Tk locus in L5178Y mouse-lymphoma cells, HI-6-dimethanesulfonate showed mutagenic activity both with and without metabolic activation, with a significant increase in small colonies. The effects were in favour of a clastogenic activity. It was concluded that the compound was mutagenic and possibly clastogenic in vitro. In contrast, the in vivo micronucleus test in rat bone-marrow did not demonstrate any genotoxic activity and the Comet assay performed in rat liver did not show any statistically or biologically significant increases in DNA strand-breaks. The results of both in vivo studies performed on two different organs with two endpoints are sufficient to conclude the absence of a genotoxic hazard in vivo and to consider that there is no genotoxic concern in humans for HI-6-dimethanesulfonate. Copyright © 2014 Elsevier B.V. All rights reserved.

Brain cholinesterase reactivation as a marker of exposure to anticholinesterase pesticides: a case study in a population of yellow-legged gull Larus michahellis (Naumann, 1840) along the northern coast of Portugal.

PubMed

Santos, Cátia S A; Monteiro, Marta S; Soares, Amadeu M V M; Loureiro, Susana

2016-01-01

Between late 2010 to early 2011, an increased mortality in gulls was observed along the northern coast of Portugal, with individuals exhibiting neurologic disorders consistent with an eventual anticholinesterase pesticide poisoning event. To clarify if this mortality was related to organophosphate (OP) and/or carbamate (CB) poisoning, chemical and spontaneous cholinesterase (ChE) reactivation was tested in the brain of the yellow-legged gull (Larus michahellis). Initial brain ChE activity in L. michahellis was 40.92 ± 5.23 U/mg of protein (average ± SE). Following chemical and spontaneous reactivation, ChE activity increased in average 70.38 ± 48.59% and 131.95 ± 92.64%, respectively. ChE reactivation was found to decrease at increasing concentrations of the oxime pyridine-2-aldoxime methochloride and dilution factor, underscoring the importance of first optimizing the assay conditions prior to its use on bird species. These results suggest that birds analysed could have been exposed to OP and CB pesticide compounds and that in most cases CB exposure appeared to be the main cause of birds poisoning. These results are an important contribution to environmental monitoring as it demonstrates the suitability of L. michaellis as sentinel species of OP and CB pesticides within an urban environment.

A comparison of reactivating and therapeutic efficacy of bispyridinium acetylcholinesterase reactivator KR-22934 with the oxime K203 and commonly used oximes (obidoxime, trimedoxime, HI-6) in tabun-poisoned rats and mice.

PubMed

Kassa, Jiri; Karasova, Jana Zdarova; Pavlikova, Ruzena; Musilek, Kamil; Kuca, Kamil; Bajgar, Jiri; Jung, Young-Sik

2011-03-01

The potency of bispyridinium acetylcholinesterase reactivator KR-22934 in reactivating tabun-inhibited acetylcholinesterase and reducing tabun-induced lethal toxic effects was compared with the oxime K203 and commonly used oximes. Studies determining percentage of reactivation of tabun-inhibited blood and tissue acetylcholinesterase in rats showed that the reactivating efficacy of KR-22934 was slightly higher than the reactivating efficacy of K203 and roughly corresponded to the reactivating efficacy of obidoxime and trimedoxime in blood and diaphragm. On the other hand, the oxime KR-22934 was not able to reactivate tabun-inhibited acetylcholinesterase in the brain. The therapeutic efficacy of all oximes studied approximately corresponded to their reactivating efficacy. Based on the results, one can conclude that the oxime KR-22934 is not suitable for the replacement of commonly used oximes for the antidotal treatment of tabun poisoning in spite of its potency to reactivate tabun-inhibited acetylcholinesterase in the peripheral compartment (blood, diaphragm).

A comparison of the reactivating and therapeutic efficacy of chosen combinations of oximes with individual oximes against VX in rats and mice.

PubMed

Kassa, Jiri; Karasova, Jana Zdarova; Sepsova, Vendula; Caisberger, Filip; Bajgar, Jiri

2011-10-01

The ability of 2 combinations of oximes (HI-6 + trimedoxime and HI-6 + K203) to reactivate VX-inhibited acetylcholinesterase and reduce acute toxicity of VX was compared with the reactivating and therapeutic efficacy of antidotal treatment involving a single oxime (HI-6, trimedoxime, K203) in rats and mice. Our results showed that the reactivating efficacy of both combinations of oximes studied in rats is significantly higher than the reactivating efficacy of all individual oximes in diaphragm and roughly corresponds to the most effective individual oxime in blood and brain. Both combinations of oximes were found to be more effective in the reduction of acute lethal toxicity of VX in mice than the antidotal treatment involving the most efficacious individual oxime although the difference is not significant. Based on the obtained data, we can conclude that the antidotal treatment involving the chosen combinations of oximes brings benefit for the reactivation of VX-inhibited acetylcholinesterase in rats and for the antidotal treatment of VX-induced acute poisoning in mice.

A comparison of the efficacy of new asymmetric bispyridinium oximes (K027, K048) with currently available oximes against tabun by in vivo methods.

PubMed

Kassa, Jiri; Kuca, Kamil; Cabal, Jiri; Paar, Martin

2006-10-01

The potency of newly developed asymmetric bispyridinium oximes (K027, K048) in reactivating tabun-inhibited acetylcholinesterase (AChE) and in eliminating tabun-induced acute toxic effects was compared with commonly used oximes (obidoxime, trimedoxime, the oxime HI-6) using in vivo methods. Studies determined the percent of reactivation of tabun-inhibited blood and tissue AChE in poisoned rats and showed that the reactivating efficacy of both newly developed oximes is comparable with obidoxime and trimedoxime, the most efficacious known reactivators of tabun-inhibited AChE. These were also found to be sufficiently efficacious in the elimination of acute lethal toxic effects in tabun-poisoned rats. The oxime HI-6, relatively efficacious against soman, did not seem to be an adequately effective oxime in reactivation of tabun-inhibited AChE and in counteracting acute lethal effects of tabun. In addition, our results confirm that the efficacy of oximes in reactivating tabun-inhibited AChE in blood, diaphragm, and brain correlates with the potency of oximes in protecting rats poisoned with supralethal doses of tabun.

New antimuscarinic agents for improved treatment of poisoning by cholinesterase inhibitors. Annual report, 1 November 1983-1 August 1984

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stubbins, J.F.

The object of this project is to find a more effective antimuscarinic agent than atropine for use as an antidote for poisoning by organophosphate cholinesterase inhibitors. To start this search, 30 structurally diverse antimuscarinic agents have been selected for initial testing. These compounds are to be evaluated for peripheral and central antimuscarinic activity in a variety of in vitro and in vivo tests in addition to determining their effectiveness as antidotes (in combination with an oxime reactivator) for poisoning by soman. Twenty-two of the compounds have now been evaluated for their ability to block acetylcholine-induced contractions in guinea pig intestinalmore » smooth muscle when compared to atropine. Ability to displace radiolabeled quinuclidinyl benzilate from muscarinic receptors of mouse brain homogenate has been determined for atropine, hyoscine and 26 of the compounds. Only triflupromazine appeared to have a distinctly greater affinity for brain receptors than muscle receptors to atropine. Intestinal smooth muscle blockade; oxotremorine tremor inhibition; muscarinic receptor subtypes.« less

A comparison of the reactivating and therapeutic efficacy of two novel bispyridinium oximes (K727, K733) with the oxime HI-6 and obidoxime in sarin-poisoned rats and mice.

PubMed

Kassa, Jiri; Sepsova, Vendula; Matouskova, Lenka; Horova, Anna; Musilek, Kamil

2015-03-01

The ability of two novel bispyridinium oximes K727 and K733 and currently available oximes (HI-6, obidoxime) to reactivate sarin-inhibited acetylcholinesterase and to reduce acute toxicity of sarin was evaluated. To investigate the reactivating efficacy of the oximes, the rats were administered intramuscularly with atropine and oximes in equitoxic doses corresponding to 5% of their LD50 values at 1 min after the intramuscular administration of sarin at a dose of 24 µg/kg (LD50). The activity of acetylcholinesterase was measured at 60 min after sarin poisoning. The LD50 value of sarin in non-treated and treated mice was assessed using probit-logarithmical analysis of death occurring within 24 h after intramuscular administration of sarin at five different doses. In vivo determined percentage of reactivation of sarin-inhibited rat blood, diaphragm and brain acetylcholinesterase showed that the potency of both novel oximes K727 and K733 to reactivate sarin-inhibited acetylcholinesterase roughly corresponds to the reactivating efficacy of obidoxime. On the other hand, the oxime HI-6 was found to be the most efficient reactivator of sarin-inhibited acetylcholinesterase. While the oxime HI-6 was able to reduce the acute toxicity of sarin >3 times, both novel oximes and obidoxime decreased the acute toxicity of sarin <2 times. Based on the results, we can conclude that the reactivating and therapeutic efficacy of both novel oximes K727 and K733 is significantly lower compared to the oxime HI-6 and, therefore, they are not suitable for the replacement of the oxime HI-6 for the antidotal treatment of acute sarin poisoning.

In vitro P-glycoprotein activity does not completely explain in vivo efficacy of novel centrally effective oxime acetylcholinesterase reactivators.

PubMed

Dail, Mary Beth; Meek, Edward Caldwell; Chambers, Howard Wayne; Chambers, Janice Elaine

2018-05-03

Novel-substituted phenoxyalkyl pyridinium oxime acetylcholinesterase (AChE) reactivators (US patent 9,227,937) that showed convincing evidence of penetration into the brains of intact rats were developed by our laboratories. The oximes separated into three groups based on their levels of brain AChE reactivation following exposure of rats to the sarin surrogate nitrophenyl isopropyl methylphosphonate (NIMP). P-glycoprotein (P-gp) is a major blood-brain barrier (BBB) transporter and requires ATP for efflux. To determine if P-gp affinity screening could be used to reduce animal use, we measured in vitro oxime-stimulated ATPase activity to see if the in vivo reactivation efficacies related to the oximes' functions as P-gp substrates. High efficacy oximes were expected to be poor P-gp substrates, thus remaining in the brain longer. The high efficacy oximes (24-35% brain AChE reactivation) were worse P-gp substrates than the low efficacy oximes (0-7% brain AChE reactivation). However, the oxime group with medium in vivo reactivation of 10-17% were even worse P-gp substrates than the high efficacy group so their reactivation ability was not reflected by P-gp export. The results suggest that in vitro P-gp ATPase activity can remove the low efficacy oximes from in vivo testing, but is not sufficient to differentiate between the top two tiers.

A structure-activity analysis of the variation in oxime efficacy against nerve agents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maxwell, Donald M.; Koplovitz, Irwin; Worek, Franz

2008-09-01

A structure-activity analysis was used to evaluate the variation in oxime efficacy of 2-PAM, obidoxime, HI-6 and ICD585 against nerve agents. In vivo oxime protection and in vitro oxime reactivation were used as indicators of oxime efficacy against VX, sarin, VR and cyclosarin. Analysis of in vivo oxime protection was conducted with oxime protective ratios (PR) from guinea pigs receiving oxime and atropine therapy after sc administration of nerve agent. Analysis of in vitro reactivation was conducted with second-order rate contants (k{sub r2}) for oxime reactivation of agent-inhibited acetylcholinesterase (AChE) from guinea pig erythrocytes. In vivo oxime PR and inmore » vitro k{sub r2} decreased as the volume of the alkylmethylphosphonate moiety of nerve agents increased from VX to cyclosarin. This effect was greater with 2-PAM and obidoxime (> 14-fold decrease in PR) than with HI-6 and ICD585 (< 3.7-fold decrease in PR). The decrease in oxime PR and k{sub r2} as the volume of the agent moiety conjugated to AChE increased was consistent with a steric hindrance mechanism. Linear regression of log (PR-1) against log (k{sub r2} {center_dot} [oxime dose]) produced two offset parallel regression lines that delineated a significant difference between the coupling of oxime reactivation and oxime protection for HI-6 and ICD585 compared to 2-PAM and obidoxime. HI-6 and ICD585 appeared to be 6.8-fold more effective than 2-PAM and obidoxime at coupling oxime reactivation to oxime protection, which suggested that the isonicotinamide group that is common to both of these oximes, but absent from 2-PAM and obidoxime, is important for oxime efficacy.« less

Detoxification of Chemical Warfare Agents by the Plant Cholinergic System

DTIC Science & Technology

2005-10-01

Cholinesterases and Anticholinesterases in Plants , and the First Isolation, Purification and Characterization of Naturally Occurring Activators of... Plants have cholinesterases (pChEs), anti-ChEs, and activators of ChEs. We have isolated pChE from mung bean sprout. We investigated 300 plants ...leaf, “Tritiacche-T123”, activates fetal bovine serum AChE, equine BChE, and pChE. This non-oxime natural plant product may offer a new approach to

The therapeutic use of localized cooling in the treatment of VX poisoning.

PubMed

Sawyer, T W; Mikler, J; Worek, F; Reiter, G; Thiermann, H; Tenn, C; Weatherby, K; Bohnert, S

2011-07-04

The organophosphate (OP) nerve agent VX is a weaponized chemical warfare agent that has also been used by terrorists against civilians. This contact poison produces characteristic signs of OP poisoning, including miosis, salivation, mastication, dysrhythmias and respiratory distress prior to death. Although successful treatment of OP poisoning can be obtained through decontamination and/or oxime reactivation of agent-inhibited cholinesterase, medical countermeasures that increase the therapeutic window for these measures would be of benefit. An anaesthetized swine model was utilized to examine the effects of lethal VX exposure to the skin, followed by cooling the exposure site prior to decontamination or treatment. The cooling was simply accomplished by using crushed ice in grip-seal plastic bags applied to the exposure sites. Cooling of skin exposed to lethal doses of VX significantly increased the window of opportunity for successful decontamination using the Reactive Skin Decontaminant Lotion(®) (RSDL(®)) or treatment with the oxime antidotes HI-6 and 2PAM. Analyses of blood VX levels showed that cooling acted to slow or prevent the entry of VX into the bloodstream from the skin. If the exposure site is known, the simple and non-invasive application of cooling provides a safe means with which to dramatically increase the therapeutic window in which decontamination and/or antidote treatment against VX are life-saving. Copyright © 2011. Published by Elsevier Ireland Ltd.

[Comparison of the reactivating effect of BI-6, a new asymmetrical bispyridinium oxime, with oxime HI-6 and obidoxime on soman-inhibited acetylcholinesterase in the diaphragm and various parts of the brain in rats].

PubMed

Kassa, J; Bajgar, J

1999-08-30

Acute poisoning with the highly toxic organophosphorus agent, soman, is not treated satisfactorily even by the most modern antidotes. In experiments on rats, the reactivating effect of a new asymmetric bispyridinium oxime BI-6 was compared with widely used oximes HI-6 and obidoxime by investigating the changes of soman-inhibited acetylcholinesterase activity in the diaphragm and various parts of the brain in rats up to three hours following soman challenge. Our findings confirm that the new oxime BI-6 is a more effective reactivator of soman-inhibited acetylcholinesterase than obidoxime but not as effective as the oxime HI-6 especially in the peripheral compartment. The new oxime BI-6 is not as effective as HI-6 which seems to have definite advantages over other oximes in the treatment of soman poisoning.

Novel cholinesterase modulators and their ability to interact with DNA

NASA Astrophysics Data System (ADS)

Janockova, Jana; Gulasova, Zuzana; Musilek, Kamil; Kuca, Kamil; Kozurkova, Maria

2013-11-01

In the present work, an interaction of four cholinesterase modulators (1-4) with calf thymus DNA was studied via spectroscopic techniques (UV-Vis, fluorescent spectroscopy and circular dichroism). From UV-Vis spectroscopic analysis, the binding constants for DNA-pyridinium oximes complexes were calculated (K = 3.5 × 104 to 1.4 × 105 M-1). All these measurements indicated that the compounds behave as effective DNA-interacting agents. Electrophoretic techniques proved that ligand 2 inhibited topoisomerase I at a concentration 5 μM.

A Common Mechanism for Resistance to Oxime Reactivation of Acetylcholinesterase Inhibited by Organophosphorus Compounds

DTIC Science & Technology

2013-01-01

application of the Hammett equation with the constants rph in the chemistry of organophosphorus compounds, Russ. Chem. Rev. 38 (1969) 795–811. [13...of oximes and OP compounds and the ability of oximes to reactivate OP- inhibited AChE. Multiple linear regression equations were analyzed using...phosphonate pairs, 21 oxime/ phosphoramidate pairs and 12 oxime/phosphate pairs. The best linear regression equation resulting from multiple regression anal

Oximes in organophosphate poisoning: 60 years of hope and despair.

PubMed

Worek, Franz; Thiermann, Horst; Wille, Timo

2016-11-25

The high number of annual fatalities following suicidal poisoning by organophosphorus (OP) pesticides and the recent homicidal use of the chemical warfare nerve agent sarin against civilian population in Syria underlines the continuous threat by these highly toxic agents. The need for an effective treatment of OP poisoning resulted in the implementation of a combination therapy with the muscarinic receptor antagonist atropine and an oxime for the reactivation of OP-inhibited acetylcholinesterase (AChE). Since the invention of the first clinically used oxime pralidoxime (2-PAM) in the 1950s ongoing research attempted to identify more effective oximes. In fact, several thousand oximes were synthesized in the past six decades. These include charged and non-charged compounds, mono- and bispyridinium oximes, asymmetric oximes, oximes with different substitutes and more recently non-oxime reactivators. Multiple in vitro and in vivo studies investigated the potential of oximes to reactivate OP-inhibited AChE and to reverse OP-induced cholinergic signs. Depending on the experimental model, the investigated species and the tested OP largely variable results were obtained by different laboratories. These findings and the inconsistent effectiveness of oximes in the treatment of OP-pesticide poisoned patients led to a continuous discussion on the value of oximes. In order to provide a forward-looking evaluation of the significance of oximes in OP poisoning multiple aspects, including intrinsic toxicity, in vitro reactivation potency, efficacy and pharmacokinetics, as well as the impact of the causative OP have to be considered. The different influencing factors in order to define the benefit and limitations of oximes in OP poisoning will be discussed. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Blood-brain barrier penetration of novel pyridinealdoxime methiodide (PAM)-type oximes examined by brain microdialysis with LC-MS/MS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okuno, Sou; Sakurada, Koichi; Ohta, Hikoto

2008-02-15

To develop a new reactivator of inhibited acetylcholinesterase (AChE) that can easily penetrate the blood-brain barrier (BBB), BBB penetration of 6 known and novel pyridinealdoxime methiodide (PAM)-type oximes (alkylPAMs) with relatively high reactivation activities was examined by in vivo rat brain microdialysis with liquid chromatography-mass spectrometry (LC-MS/MS). The 50% lethal dose (LD{sub 50}) of alkylPAMs was intravenously determined for Wistar rats, then the limit of detection, quantification range and linearity of the calibration curve of the alkylPAMs in dialysate and blood were determined by LC-MS/MS. Following 10% LD{sub 50} intravenous administration of the alkylPAMs, 4-[(hydroxyimino) methyl]-1-(2-phenylethyl) pyridinium bromide (4-PAPE) andmore » 4-[(hydroxyimino) methyl]-1-octylpyridinium bromide (4-PAO) appeared in the dialysate. Striatal extracellular fluid/blood concentration ratios were 0.039 {+-} 0.018 and 0.301 {+-} 0.183 (mean {+-} SEM), respectively, 1 h after treatment. This is the first report of BBB penetration of 4-PAPE, and the concentration ratio was smaller than that of 2-PAM.The mean BBB penetration of 4-PAO was approximately 30%, indicating that intravenous administration of 4-PAO may be effective for the reactivation of blocked cholinesterase in the brain. However, the toxicity of 4-PAO (LD{sub 50}; 8.89 mg/kg) was greater than that of 2-PAM. Further investigation is required to determine the effects of these alkylPAMs in organophosphate poisoning.« less

A comprehensive evaluation of novel oximes in creation of butyrylcholinesterase-based nerve agent bioscavengers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katalinić, Maja; Maček Hrvat, Nikolina

A well-considered treatment of acute nerve agents poisoning involves the exogenous administration of butyrylcholinesterase (BChE, EC 3.1.1.8) as a stoichiometric bioscavenger efficient in preventing cholinergic crises caused by acetylcholinesterase (AChE, EC 3.1.1.7) inhibition. An additional improvement in medical countermeasures would be to use oximes that could reactivate BChE as well to upgrade bioscavenging from stoichiometric to oxime-assisted catalytic. Therefore, in this paper we investigated the potency of 39 imidazolium and benzimidazolium oximes (36 compounds synthesized for the first time) to be considered as the reactivators specifically designed for reactivation of phosphylated human BChE. Their efficiency in the reactivation of paraoxon-,more » VX-, and tabun-inhibited human BChE, as well as human AChE was tested and compared with the efficiencies of HI-6 and obidoxime, used in medical practice today. A comprehensive analysis was performed for the most promising oximes defining kinetic parameters of reactivation as well as interactions with uninhibited BChE. Furthermore, experimental data were compared with computational studies (docking, QSAR analysis) as a starting point in future oxime structure refinement. Considering the strict criteria set for in vivo applications, we determined the cytotoxicity of lead oximes on two cell lines. Among the tested oxime library, one imidazolium compound was selected for preliminary in vivo antidotal study in mice. The obtained protection in VX poisoning outlines its potential in development oxime-assisted OP-bioscavenging with BChE. - Highlights: • 36 new imidazolium and benzimidazolium oximes were designed and synthesized. • In vitro reactivation kinetics of phosphylated butyrylcholinesterase was studded. • The modes of actions were elucidated by QSAR and docking simulations. • Protection in VX poisoning was 6.3 × LD{sub 50} in in vivo antidotal study in mice. • Imidazolium oxime-assisted catalysis is feasible for OP-bioscavenging with BChE.« less

Human Carboxylesterase 1 Stereoselectively Binds the Nerve Agent Cyclosarin and Spontaneously Hydrolyzes the Nerve Agent Sarin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hemmert, Andrew C.; Otto, Tamara C.; Wierdl, Monika

Organophosphorus (OP) nerve agents are potent toxins that inhibit cholinesterases and produce a rapid and lethal cholinergic crisis. Development of protein-based therapeutics is being pursued with the goal of preventing nerve agent toxicity and protecting against the long-term side effects of these agents. The drug-metabolizing enzyme human carboxylesterase 1 (hCE1) is a candidate protein-based therapeutic because of its similarity in structure and function to the cholinesterase targets of nerve agent poisoning. However, the ability of wild-type hCE1 to process the G-type nerve agents sarin and cyclosarin has not been determined. We report the crystal structure of hCE1 in complex withmore » the nerve agent cyclosarin. We further use stereoselective nerve agent analogs to establish that hCE1 exhibits a 1700- and 2900-fold preference for the P{sub R} enantiomers of analogs of soman and cyclosarin, respectively, and a 5-fold preference for the P{sub S} isomer of a sarin analog. Finally, we show that for enzyme inhibited by racemic mixtures of bona fide nerve agents, hCE1 spontaneously reactivates in the presence of sarin but not soman or cyclosarin. The addition of the neutral oxime 2,3-butanedione monoxime increases the rate of reactivation of hCE1 from sarin inhibition by more than 60-fold but has no effect on reactivation with the other agents examined. Taken together, these data demonstrate that hCE1 is only reactivated after inhibition with the more toxic P{sub S} isomer of sarin. These results provide important insights toward the long-term goal of designing novel forms of hCE1 to act as protein-based therapeutics for nerve agent detoxification.« less

Comparison of oxime reactivation and aging of nerve agent-inhibited monkey and human acetylcholinesterases.

PubMed

Luo, Chunyuan; Tong, Min; Maxwell, Donald M; Saxena, Ashima

2008-09-25

Non-human primates are valuable animal models that are used for the evaluation of nerve agent toxicity as well as antidotes and results from animal experiments are extrapolated to humans. It has been demonstrated that the efficacy of an oxime primarily depends on its ability to reactivate nerve agent-inhibited acetylcholinesterase (AChE). If the in vitro oxime reactivation of nerve agent-inhibited animal AChE is similar to that of human AChE, it is likely that the results of an in vivo animal study will reliably extrapolate to humans. Therefore, the goal of this study was to compare the aging and reactivation of human and different monkey (Rhesus, Cynomolgus, and African Green) AChEs inhibited by GF, GD, and VR. The oximes examined include the traditional oxime 2-PAM, two H-oximes HI-6 and HLo-7, and the new candidate oxime MMB4. Results indicate that oxime reactivation of all three monkey AChEs was very similar to human AChE. The maximum difference in the second-order reactivation rate constant between human and three monkey AChEs or between AChEs from different monkey species was 5-fold. Aging rate constants of GF-, GD-, and VR-inhibited monkey AChEs were very similar to human AChE except for GF-inhibited monkey AChEs, which aged 2-3 times faster than the human enzyme. The results of this study suggest that all three monkey species are suitable animal models for nerve agent antidote evaluation since monkey AChEs possess similar biochemical/pharmacological properties to human AChE.

Oxime-Induced Reactivation of Carboxylesterase Inhibited by Organophosphorus Compounds

DTIC Science & Technology

1993-05-13

detoxication enzyme for OP compounds (Maxwell, 1992a), when in the presence of an uncharged oxime, becomes even more effective because it is easily...Wolring, 1984). Therefore, oxime-induced reactivation of OP-inhibited CaE for protection by enhancement of OP detoxication occurs at approximately the

Recent advances in evaluation of oxime efficacy in nerve agent poisoning by in vitro analysis.

PubMed

Worek, F; Eyer, P; Aurbek, N; Szinicz, L; Thiermann, H

2007-03-01

The availability of highly toxic organophosphorus (OP) warfare agents (nerve agents) underlines the necessity for an effective medical treatment. Acute OP toxicity is primarily caused by inhibition of acetylcholinesterase (AChE). Reactivators (oximes) of inhibited AChE are a mainstay of treatment, however, the commercially available compounds, obidoxime and pralidoxime, are considered to be rather ineffective against various nerve agents, e.g. soman and cyclosarin. This led to the synthesis and investigation of numerous oximes in the past decades. Reactivation of OP-inhibited AChE is considered to be the most important reaction of oximes. Clinical data from studies with pesticide-poisoned patients support the assumption that the various reactions between AChE, OP and oxime, i.e. inhibition, reactivation and aging, can be investigated in vitro with human AChE. In contrast to animal experiments such in vitro studies with human tissue enable the evaluation of oxime efficacy without being affected by species differences. In the past few years numerous in vitro studies were performed by different groups with a large number of oximes and methods were developed for extrapolating in vitro data to different scenarios of human nerve agent poisoning. The present status in the evaluation of new oximes as antidotes against nerve agent poisoning will be discussed.

Structural Study of the Complex Stereoselectivity of Human Butyrylcholinesterase for the Neurotoxic V-agents*

PubMed Central

Wandhammer, Marielle; Carletti, Eugénie; Van der Schans, Marcel; Gillon, Emilie; Nicolet, Yvain; Masson, Patrick; Goeldner, Maurice; Noort, Daan; Nachon, Florian

2011-01-01

Nerve agents are chiral organophosphate compounds (OPs) that exert their acute toxicity by phosphorylating the catalytic serine of acetylcholinesterase (AChE). The inhibited cholinesterases can be reactivated using oximes, but a spontaneous time-dependent process called aging alters the adduct, leading to resistance toward oxime reactivation. Human butyrylcholinesterase (BChE) functions as a bioscavenger, protecting the cholinergic system against OPs. The stereoselectivity of BChE is an important parameter for its efficiency at scavenging the most toxic OPs enantiomer for AChE. Crystals of BChE inhibited in solution or in cristallo with racemic V-agents (VX, Russian VX, and Chinese VX) systematically show the formation of the PS adduct. In this configuration, no catalysis of aging seems possible as confirmed by the three-dimensional structures of the three conjugates incubated over a period exceeding a week. Crystals of BChE soaked in optically pure VXR-(+) and VXS-(−) solutions lead to the formation of the PS and PR adduct, respectively. These structural data support an in-line phosphonylation mechanism. Additionally, they show that BChE reacts with VXR-(+) in the presence of racemic mixture of V-agents, at odds with earlier kinetic results showing a moderate higher inhibition rate for VXS-(−). These combined results suggest that the simultaneous presence of both enantiomers alters the enzyme stereoselectivity. In summary, the three-dimensional data show that BChE reacts preferentially with PR enantiomer of V-agents and does not age, in complete contrast to AChE, which is selectively inhibited by the PS enantiomer and ages. PMID:21454498

Changes of rat plasma total low molecular weight antioxidant level after tabun exposure and consequent treatment by acetylcholinesterase reactivators.

PubMed

Pohanka, Miroslav; Karasova, Jana Zdarova; Musilek, Kamil; Kuca, Kamil; Jung, Young-Sik; Kassa, Jiri

2011-02-01

These experiments were performed on a rat model. The rats were divided into eight groups and consequently exposed to either a saline solution (control), atropine or a combination of atropine and tabun. The reactivation efficacy of the oximes was estimated on the rats exposed to tabun, atropine and a reactivator of AChE. The oximes HI-6, obidoxime, trimedoxime, K203 and KR-22836 were used as representative compounds of commonly available and new AChE reactivators. Besides the positive effect of the administered reactivators on blood AChE activity, the sizable modulation of low molecular weight antioxidant (LMWA) levels was also determined. The LMWA levels in the the animals treated with the oxime reactivators were decreased in comparison with the animals treated by atropine alone. It was found that the levels of LMWA returned to the level found in the control animals when either trimedoxime, K203 or KR-22836 were administered. The principle of oxime reactivator function and a novel insight into AChE activity regulation and oxidative stress is discussed.

Reactivation of organophosphate-inhibited human acetylcholinesterase by isonitrosoacetone (MINA): a kinetic analysis.

PubMed

Worek, Franz; Thiermann, Horst

2011-11-15

Treatment of poisoning by highly toxic organophosphorus compounds (OP) with atropine and an acetylcholinesterase (AChE) reactivator (oxime) is of limited effectiveness in case of different nerve agents and pesticides. One challenge is the reactivation of OP-inhibited brain AChE which shows inadequate success with charged pyridinium oximes. Recent studies with high doses of the tertiary oxime isonitrosoacetone (MINA) indicated a beneficial effect on central and peripheral AChE and on survival in nerve agent poisoned guinea pigs. Now, an in vitro study was performed to determine the reactivation kinetics of MINA with tabun-, sarin-, cyclosarin-, VX- and paraoxon-inhibited human AChE. MINA showed an exceptionally low affinity to inhibited AChE but, with the exception of tabun-inhibited AChE, a moderate to high reactivity. In comparison to the pyridinium oximes obidoxime, 2-PAM and HI-6 the affinity and reactivity of MINA was in most cases lower and in relation to the most effective reactivators, the second order reactivation constant of MINA was 500 to 3400-fold lower. Hence, high in vivo MINA concentrations would be necessary to achieve at least partial reactivation. This assumption corresponds to in vivo data showing a dose-dependent effect on reactivation and survival in animals. In view, of the toxic potential of MINA in animals human studies would be necessary to determine the tolerability and pharmacokinetics of MINA in order to enable a proper assessment of the value of this oxime as an antidote in OP poisoning. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Worek, Franz, E-mail: franzworek@bundeswehr.org; Wille, Timo; Aurbek, Nadine

Treatment of poisoning by highly toxic organophosphorus compounds (OP, nerve agents) is a continuous challenge. Standard treatment with atropine and a clinically used oxime, obidoxime or pralidoxime is inadequate against various nerve agents. For ethical reasons testing of oxime efficacy has to be performed in animals. Now, it was tempting to investigate the reactivation kinetics of MMB-4, a candidate oxime to replace pralidoxime, with nerve agent-inhibited acetylcholinesterase (AChE) from human and animal origin in order to provide a kinetic basis for the proper assessment of in vivo data. By applying a modified kinetic approach, allowing the use of necessary highmore » MMB-4 concentrations, it was possible to determine the reactivation constants with sarin-, cyclosarin-, VX-, VR- and tabun-inhibited AChE. MMB-4 exhibited a high reactivity and low affinity towards OP-inhibited AChE, except of tabun-inhibited enzyme where MMB-4 had an extremely low reactivity. Species differences between human and animal AChE were low (Cynomolgus) to moderate (swine, guinea pig). Due to the high reactivity of MMB-4 a rapid reactivation of inhibited AChE can be anticipated at adequate oxime concentrations which are substantially higher compared to HI-6. Additional studies are necessary to determine the in vivo toxicity, tolerability and pharmacokinetics of MMB-4 in humans in order to enable a proper assessment of the value of this oxime as an antidote against nerve agent poisoning.« less

Application of brain cholinesterase reactivation to differentiate between organophosphorus and carbamate pesticide exposure in wild birds

USGS Publications Warehouse

Smith, M.R.; Thomas, N.J.; Hulse, C.

1995-01-01

Brain cholinesterase activity was measured to evaluate pesticide exposure in wild birds. Thermal reactivation of brain cholinesterase was used to differentiate between carbamate and organophosphorus pesticide exposure. Brain cholinesterase activity was compared with gas chromatography and mass spectrometry of stomach contents. Pesticides were identified and confirmed in 86 of 102 incidents of mortality from 29 states within the USA from 1986 through 1991. Thermal reactivation of cholinesterase activity was used to correctly predict carbamates in 22 incidents and organophosphates in 59 incidents. Agreement (P < 0.001) between predictions based on cholinesterase activities and GC/MS results was significant.

Reactivation of organophosphate-inhibited human, Cynomolgus monkey, swine and guinea pig acetylcholinesterase by MMB-4: a modified kinetic approach.

PubMed

Worek, Franz; Wille, Timo; Aurbek, Nadine; Eyer, Peter; Thiermann, Horst

2010-12-15

Treatment of poisoning by highly toxic organophosphorus compounds (OP, nerve agents) is a continuous challenge. Standard treatment with atropine and a clinically used oxime, obidoxime or pralidoxime is inadequate against various nerve agents. For ethical reasons testing of oxime efficacy has to be performed in animals. Now, it was tempting to investigate the reactivation kinetics of MMB-4, a candidate oxime to replace pralidoxime, with nerve agent-inhibited acetylcholinesterase (AChE) from human and animal origin in order to provide a kinetic basis for the proper assessment of in vivo data. By applying a modified kinetic approach, allowing the use of necessary high MMB-4 concentrations, it was possible to determine the reactivation constants with sarin-, cyclosarin-, VX-, VR- and tabun-inhibited AChE. MMB-4 exhibited a high reactivity and low affinity towards OP-inhibited AChE, except of tabun-inhibited enzyme where MMB-4 had an extremely low reactivity. Species differences between human and animal AChE were low (Cynomolgus) to moderate (swine, guinea pig). Due to the high reactivity of MMB-4 a rapid reactivation of inhibited AChE can be anticipated at adequate oxime concentrations which are substantially higher compared to HI-6. Additional studies are necessary to determine the in vivo toxicity, tolerability and pharmacokinetics of MMB-4 in humans in order to enable a proper assessment of the value of this oxime as an antidote against nerve agent poisoning. Copyright © 2010 Elsevier Inc. All rights reserved.

Development and validation of a FIA/UV-vis method for pK(a) determination of oxime based acetylcholinesterase reactivators.

PubMed

Musil, Karel; Florianova, Veronika; Bucek, Pavel; Dohnal, Vlastimil; Kuca, Kamil; Musilek, Kamil

2016-01-05

Acetylcholinesterase reactivators (oximes) are compounds used for antidotal treatment in case of organophosphorus poisoning. The dissociation constants (pK(a1)) of ten standard or promising acetylcholinesterase reactivators were determined by ultraviolet absorption spectrometry. Two methods of spectra measurement (UV-vis spectrometry, FIA/UV-vis) were applied and compared. The soft and hard models for calculation of pK(a1) values were performed. The pK(a1) values were recommended in the range 7.00-8.35, where at least 10% of oximate anion is available for organophosphate reactivation. All tested oximes were found to have pK(a1) in this range. The FIA/UV-vis method provided rapid sample throughput, low sample consumption, high sensitivity and precision compared to standard UV-vis method. The hard calculation model was proposed as more accurate for pK(a1) calculation. Copyright © 2015 Elsevier B.V. All rights reserved.

Efficacy of Recommended Pre-Hospital Human Equivalent Doses of Atropine and Pralidoxime against the Toxic Effects of Carbamate Poisoning in the Hartley Guinea Pig

PubMed Central

Brittain, Matthew K.; McGarry, Kevin G.; Moyer, Robert A.; Babin, Michael C.; Jett, David A.; Platoff, Gennady E.; Yeung, David T.

2016-01-01

Purpose Aldicarb and methomyl are carbamate pesticides commonly implicated in human poisonings. The primary toxic mechanism of action for carbamate poisoning is cholinesterase (ChE) inhibition. As such, it is logical to assume that the currently accepted therapies for organophosphate poisoning [muscarinic antagonist atropine and the oxime acetylcholinesterase reactivator pralidoxime chloride (2-PAM Cl),], could afford therapeutic protection. However, oximes have been shown to be contraindicated for poisoning by some carbamates. Methods A protective ratio study was conducted in guinea pigs to evaluate the efficacy of atropine and 2-PAM Cl. ChE activity was determined in both the blood and cerebral cortex.. Results Co-administration of atropine free base (0.4 mg/kg) and 2-PAM Cl (25.7 mg/kg) demonstrated protective ratios of 2 and 3 against aldicarb and methomyl, respectively, relative to saline. The data reported here show that this protection was primarily mediated by the action of atropine. The reactivator 2-PAM Cl had neither positive nor negative effects on survival. Both blood acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were significantly reduced at 15 minutes post-challenge but gradually returned to normal within 24 h. Analysis of cerebral cortex showed that BChE, but not AChE, activity was reduced in animals that succumbed prior to 24 h after challenge. Conclusion The results suggest that co-administration of atropine and 2-PAM Cl at the currently recommended human equivalent doses for use in the pre-hospital setting to treat organophosphorus nerve agent and pesticide poisoning would likely also be effective against aldicarb or methomyl poisoning. PMID:27102179

Can hydroxylamine be a more potent nucleophile for the reactivation of tabun-inhibited AChE than prototype oxime drugs? An answer derived from quantum chemical and steered molecular dynamics studies.

PubMed

Lo, Rabindranath; Ganguly, Bishwajit

2014-07-29

Organophosphorus nerve agents are highly toxic compounds which strongly inhibit acetylcholinesterase (AChE) in the blood and in the central nervous system (CNS). Tabun is one of the highly toxic organophosphorus (OP) compounds and is resistant to many oxime drugs formulated for the reactivation of AChE. The reactivation mechanism of tabun-conjugated AChE with various drugs has been examined with density functional theory and ab initio quantum chemical calculations. The presence of a lone-pair located on the amidic group resists the nucleophilic attack at the phosphorus center of the tabun-conjugated AChE. We have shown that the newly designed drug candidate N-(pyridin-2-yl)hydroxylamine, at the MP2/6-31+G*//M05-2X/6-31G* level in the aqueous phase with the polarizable continuum solvation model (PCM), is more effective in reactivating the tabun-conjugated AChE than typical oxime drugs. The rate determining activation barrier with N-(pyridin-2-yl)hydroxylamine was found to be ∼1.7 kcal mol(-1), which is 7.2 kcal mol(-1) lower than the charged oxime trimedoxime (one of the most efficient reactivators in tabun poisonings). The greater nucleophilicity index (ω(-)) and higher CHelpG charge of pyridinylhydroxylamine compared to TMB4 support this observation. Furthermore, we have also examined the reactivation process of tabun-inhibited AChE with some other bis-quaternary oxime drug candidates such as methoxime (MMB4) and obidoxime. The docking analysis suggests that charged bis-quaternary pyridinium oximes have greater binding affinity inside the active-site gorge of AChE compared to the neutral pyridinylhydroxylamine. The peripheral ligand attached to the neutral pyridinylhydroxylamine enhanced the binding with the aromatic residues in the active-site gorge of AChE through effective π-π interactions. Steered molecular dynamics (SMD) simulations have also been performed with the charged oxime (TMB4) and the neutral hydroxylamine. From protein-drug interaction parameters (rupture force profiles, hydrogen bonds, hydrophobic interactions), geometry and the orientation of the drug candidates, the hydroxylamine is suggested to orchestrate the reactivation process better than TMB4. Furthermore, the calculated log P values show the effective penetration of the neutral drug candidate through the blood-brain barrier. The toxicity measurements and the IC50 values (a measure of the intrinsic affinity toward AChE) suggest that the pyridinylhydroxylamine compound could have similar toxic behavior compared to the prototype oxime antidotes used for reactivation purposes. The newly designed pyridinylhydroxylamine drug candidate can be an effective antidote both kinetically and structurally to reactivate the tabun-inhibited enzyme.

New antimuscarinic agents for improved treatment of poisoning by cholinesterase inhibitors. Annual progress report No. 1, 1 November 1982-31 October 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stubbins, J.F.

The object of this project is to find a more effective antimuscarinic agent than atropine for use as an antidote for poisoning by organophosphate cholinesterase inhibitors. To start this search, 22 structurally-diverse antimuscarinic agents have been selected for initial testing. These compounds are to be evaluated for peripheral and central antimuscarinic activity in a variety of in vitro and in vivo tests in addition to determining their effectiveness as antidotes (in combination with an oxime reactivator) for poisoning by soman. Fifteen of the compounds have now been evaluated for ability to block acetylcholine-induced contractions in guinea pig intestinal smooth musclemore » compared to atropine. Ability to displace radiolabeled quinuclidinyl benzilate from muscarinic receptors of mouse brain homogenate has been determined for atropine, scopolamine and 19 of the compounds. Several of these compounds have a relatively stronger affinity for brain than for intestinal muscarinic receptors. Atropine, scopolamine and 12 of the compounds have also been examined as inhibitors of tremors induced by oxotremorine in mice. Two of the compounds are much more potent than atropine. None of the compounds have been tested as yet as antidotes for soman poisoning. Samples of the test compounds are being sent to the Medical Research Institute of Chemical Defense for evaluation of this property.« less

α-Diazo oxime ethers for N-heterocycle synthesis.

PubMed

Choi, Subin; Ha, Sujin; Park, Cheol-Min

2017-06-01

This Feature Article introduces the preparation and synthetic utility of α-diazo oxime ethers. α-Oximino carbenes are useful synthons for N-heterocycles, and can be easily prepared from α-diazo oxime ethers as precursors. We begin with the preparation of α-diazo oxime ethers and their application in [3+2] cycloaddition. It turns out that the nature of metals bound to carbenes plays a crucial role in modulating the reactivity of α-oximino carbenes, in which copper carbenes smoothly react with enamines, whereas the less reactive enol ethers and nitriles require gold carbenes. In Section 3.2, a discussion on N-O and C-H bond activation is presented. Carbenes derived from diazo oxime ethers show unique reactivity towards N-O and C-H bond activation, in which the proximity of the two functionalities, carbene and oxime ether, dictates the preferred reaction pathways toward pyridines, pyrroles, and 2H-azirines. In Section 3.3, the development of tandem reactions based on α-diazo oxime ethers is discussed. The nature of carbenes in which whether free carbenes or metal complexes are involved dissects the pathway and forms different types of 2H-azirines. The 2H-azirine formation turned out to be an excellent platform for the tandem synthesis of N-heterocycles including pyrroles and pyridines. In the last section, we describe the electrophilic activation of 2H-azirines with vinyl carbenes and oximino carbenes. The resulting azirinium species undergo rapid ring expansion rearrangements to form pyridines and pyrazines.

In vitro effects of acetylcholinesterase reactivators on monoamine oxidase activity.

PubMed

Fišar, Zdeněk; Hroudová, Jana; Korábečný, Jan; Musílek, Kamil; Kuča, Kamil

2011-03-05

Administration of acetylcholinesterase (AChE) reactivators (oximes) is usually used in order to counteract the poisoning effects of nerve agents. The possibility was suggested that oximes may show some therapeutic and/or adverse effects through their action in central nervous system. There are no sufficient data about interaction of oximes with monoaminergic neurotransmitter's systems in the brain. Oxime-type AChE reactivators pralidoxime, obidoxime, trimedoxime, methoxime and HI-6 were tested for their potential to affect the activity of monoamine oxidase of type A (MAO-A) and type B (MAO-B) in crude mitochondrial fraction of pig brains. The compounds were found to inhibit fully MAO-A with half maximal inhibitory concentration (IC(50)) of 0.375 mmol/l (pralidoxime), 1.53 mmol/l (HI-6), 2.31 mmol/l (methoxime), 2.42 mmol/l (obidoxime) and 4.98 mmol/l (trimedoxime). Activity of MAO-B was fully inhibited by HI-6 and pralidoxime only with IC(50) 4.81 mmol/l and 11.01 mmol/l, respectively. Methoxime, obidoxime and trimedoxime displayed non-monotonic concentration dependent effect on MAO-B activity. Because oximes concentrations effective for MAO inhibition could not be achieved in vivo at the cerebral level, we suppose that oximes investigated do not interfere with brain MAO at therapeutically relevant concentrations. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Kinetic analysis of interactions of paraoxon and oximes with human, Rhesus monkey, swine, rabbit, rat and guinea pig acetylcholinesterase.

PubMed

Worek, Franz; Aurbek, Nadine; Wille, Timo; Eyer, Peter; Thiermann, Horst

2011-01-15

Previous in vitro studies showed marked species differences in the reactivating efficiency of oximes between human and animal acetylcholinesterase (AChE) inhibited by organophosphorus (OP) nerve agents. These findings provoked the present in vitro study which was designed to determine the inhibition, aging, spontaneous and oxime-induced reactivation kinetics of the pesticide paraoxon, serving as a model compound for diethyl-OP, and the oximes obidoxime, pralidoxime, HI 6 and MMB-4 with human, Rhesus monkey, swine, rabbit, rat and guinea pig erythrocyte AChE. Comparable results were obtained with human and monkey AChE. Differences between human, swine, rabbit, rat and guinea pig AChE were determined for the inhibition and reactivation kinetics. A six-fold difference of the inhibitory potency of paraoxon with human and guinea pig AChE was recorded while only moderate differences of the reactivation constants between human and animal AChE were determined. Obidoxime was by far the most effective reactivator with all tested species. Only minor species differences were found for the aging and spontaneous reactivation kinetics. The results of the present study underline the necessity to determine the inhibition, aging and reactivation kinetics in vitro as a basis for the development of meaningful therapeutic animal models, for the proper assessment of in vivo animal data and for the extrapolation of animal data to humans. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Oximes: Inhibitors of Human Recombinant Acetylcholinesterase. A Structure-Activity Relationship (SAR) Study

PubMed Central

Sepsova, Vendula; Karasova, Jana Zdarova; Korabecny, Jan; Dolezal, Rafael; Zemek, Filip; Bennion, Brian J.; Kuca, Kamil

2013-01-01

Acetylcholinesterase (AChE) reactivators were developed for the treatment of organophosphate intoxication. Standard care involves the use of anticonvulsants (e.g., diazepam), parasympatolytics (e.g., atropine) and oximes that restore AChE activity. However, oximes also bind to the active site of AChE, simultaneously acting as reversible inhibitors. The goal of the present study is to determine how oxime structure influences the inhibition of human recombinant AChE (hrAChE). Therefore, 24 structurally different oximes were tested and the results compared to the previous eel AChE (EeAChE) experiments. Structural factors that were tested included the number of pyridinium rings, the length and structural features of the linker, and the number and position of the oxime group on the pyridinium ring. PMID:23959117

Synthesis and in vitro reactivation study of isonicotinamide derivatives of 2-(hydroxyimino)-N-(pyridin-3-yl)acetamide as reactivators of Sarin and VX inhibited human acetylcholinesterase (hAChE).

PubMed

Karade, Hitendra N; Raviraju, G; Acharya, B N; Valiveti, Aditya Kapil; Bhalerao, Uma; Acharya, Jyotiranjan

2016-09-15

Previously (Karade et al., 2014), we have reported the synthesis and in vitro evaluation of bis-pyridinium derivatives of pyridine-3-yl-(2-hydroxyimino acetamide), as reactivators of sarin and VX inhibited hAChE. Few of the molecules showed superior in vivo protection efficacy (mice model) (Kumar et al., 2014; Swami et al., 2016) in comparison to 2-PAM against DFP and sarin poisoning. Encouraged by these results, herein we report the synthesis and in vitro evaluation of isonicotinamide derivatives of pyridine-3-yl-(2-hydroxyimino acetamide) (4a-4d) against sarin and VX inhibited erythrocyte ghost hAChE. Reactivation kinetics of these compounds was studied and the determined kinetic parameters were compared with that of commercial reactivators viz. 2-PAM and obidoxime. In comparison to 2-PAM and obidoxime, oxime 4a and 4b exhibited enhanced reactivation efficacy toward sarin inhibited hAChE while oxime 4c showed far greater reactivation efficacy toward VX inhibited hAChE. The acid dissociation constant and IC50 values of these oximes were determined and correlated with the observed reactivation potential. Copyright © 2016 Elsevier Ltd. All rights reserved.

From Split to Sibenik: The Tortuous Pathway in the Cholinesterase Field

PubMed Central

Taylor, Palmer

2010-01-01

The interim between the first and tenth International Cholinesterase meetings has seen remarkable advances associated with the applications of structural biology and recombinant DNA methodology to our field. The cloning of the cholinesterase genes led to the identification of a new super family of proteins, termed the α,β–hydrolase fold; members of this family possess a four helix bundle capable of linking structural subunits to the functioning globular protein. Sequence comparisons and three dimensional structural studies revealed unexpected cousins possessing this fold that, in turn, revealed three distinct functions for the α,β-hydrolase proteins. These encompass: (1) a capacity for hydrolytic cleavage of a great variety of substrates, (2) a heterophilic adhesion function that results in trans-synaptic associations in linked neurons, (3) a chaperone function leading to stabilization of nascent protein and its trafficking to an extracellular or secretory storage location. The analysis and modification of structure may go beyond understanding mechanism, since it may be possible to convert the cholinesterases to efficient detoxifying agents of organophosphatases assisted by added oximes. Also, the study of the relationship between the α,β–hydrolase fold proteins and their biosynthesis may yield means by which aberrant trafficking may be corrected, enhancing expression of mutant proteins. Those engaged in cholinesterase research should take great pride in our accomplishments punctuated by the series of ten meetings. The momentum established and initial studies with related proteins all hold great promise for the future. PMID:20493179

Discovery of New Classes of Compounds that Reactivate Acetylcholinesterase Inhibited by Organophosphates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katz, Francine S.; Pecic, Stevan; Tran, Timothy H.

Acetylcholinesterase (AChE) that has been covalently inhibited by organophosphate compounds (OPCs), such as nerve agents and pesticides, has traditionally been reactivated by using nucleophilic oximes. There is, however, a clearly recognized need for new classes of compounds with the ability to reactivate inhibited AChE with improved in vivo efficacy. Here we describe our discovery of new functional groups—Mannich phenols and general bases—that are capable of reactivating OPC-inhibited AChE more efficiently than standard oximes and we describe the cooperative mechanism by which these functionalities are delivered to the active site. These discoveries, supported by preliminary in vivo results and crystallographic data,more » significantly broaden the available approaches for reactivation of AChE.« less

Evolution of and perspectives on therapeutic approaches to nerve agent poisoning.

PubMed

Masson, Patrick

2011-09-25

After more than 70 years of considerable efforts, research on medical defense against nerve agents has come to a standstill. Major progress in medical countermeasures was achieved between the 50s and 70s with the development of anticholinergic drugs and carbamate-based pretreatment, the introduction of pyridinium oximes as antidotes, and benzodiazepines in emergency treatments. These drugs ensure good protection of the peripheral nervous system and mitigate the acute effects of exposure to lethal doses of nerve agents. However, pyridostigmine and cholinesterase reactivators currently used in the armed forces do not protect/reactivate central acetylcholinesterases. Moreover, other drugs used are not sufficiently effective in protecting the central nervous system against seizures, irreversible brain damages and long-term sequelae of nerve agent poisoning.New developments of medical counter-measures focus on: (a) detoxification of organophosphorus molecules before they react with acetylcholinesterase and other physiological targets by administration of stoichiometric or catalytic scavengers; (b) protection and reactivation of central acetylcholinesterases, and (c) improvement of neuroprotection following delayed therapy.Future developments will aim at treatment of acute and long-term effects of low level exposure to nerve agents, research on alternative routes for optimizing drug delivery, and therapies. Though gene therapy for in situ generation of bioscavengers, and cell therapy based on neural progenitor engraftment for neuronal regeneration have been successfully explored, more studies are needed before practical medical applications can be made of these new approaches. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Interactions of vanadium( iv ) with amidoxime ligands: redox reactivity

DOE PAGES

Parker, B. F.; Hohloch, S.; Pankhurst, J. R.; ...

2018-01-01

Vanadium is the main competitor for uranium extraction from seawater, and V( iv ) comprises a minor but important portion of this. V( iv ) undergoes redox reactions with oximes and amidoxime ligands under seawater-relevant conditions, leading to V( v ) complexes and loss of oxime functional groups.

Inhibition pathways of the potent organophosphate CBDP with cholinesterases revealed by X-ray crystallographic snapshots and mass spectrometry.

PubMed

Carletti, Eugénie; Colletier, Jacques-Philippe; Schopfer, Lawrence M; Santoni, Gianluca; Masson, Patrick; Lockridge, Oksana; Nachon, Florian; Weik, Martin

2013-02-18

Tri-o-cresyl-phosphate (TOCP) is a common additive in jet engine lubricants and hydraulic fluids suspected to have a role in aerotoxic syndrome in humans. TOCP is metabolized to cresyl saligenin phosphate (CBDP), a potent irreversible inhibitor of butyrylcholinesterase (BChE), a natural bioscavenger present in the bloodstream, and acetylcholinesterase (AChE), the off-switch at cholinergic synapses. Mechanistic details of cholinesterase (ChE) inhibition have, however, remained elusive. Also, the inhibition of AChE by CBDP is unexpected, from a structural standpoint, i.e., considering the narrowness of AChE active site and the bulkiness of CBDP. In the following, we report on kinetic X-ray crystallography experiments that provided 2.7-3.3 Å snapshots of the reaction of CBDP with mouse AChE and human BChE. The series of crystallographic snapshots reveals that AChE and BChE react with the opposite enantiomers and that an induced-fit rearrangement of Phe297 enlarges the active site of AChE upon CBDP binding. Mass spectrometry analysis of aging in either H(2)(16)O or H(2)(18)O furthermore allowed us to identify the inhibition steps, in which water molecules are involved, thus providing insights into the mechanistic details of inhibition. X-ray crystallography and mass spectrometry show the formation of an aged end product formed in both AChE and BChE that cannot be reactivated by current oxime-based therapeutics. Our study thus shows that only prophylactic and symptomatic treatments are viable to counter the inhibition of AChE and BChE by CBDP.

Recent Advances in the Treatment of Organophosphorous Poisonings

PubMed Central

Balali-Mood, Mahdi; Saber, Hamidreza

2012-01-01

Organophosphorous compounds have been employed as pesticides and chemical warfare nerve agents. Toxicity of organophosphorous compounds is a result of excessive cholinergic stimulation through inhibition of acetyl cholinesterase. Clinical manifestations include cholinergic syndromes, central nervous system and cardiovascular disorders. Organophosphorous pesticide poisonings are common in developing worlds including Iran and Sri Lanka. Nerve agents were used during the Iraq-Iran war in 1983-1988 and in a terrorist attack in Japan in 1994-1995. Following decontamination, depending on the severity of intoxication the administration of atropine to counteract muscarinic over-stimulation, and an oxime to reactivate acetyl cholinesterase are indicated. Supportive and intensive care therapy including diazepam to control convulsions and mechanical respiration may be required. Recent investigations have revealed that intravenous infusion of sodium bicarbonate to produce mild to moderate alkalinization is effective. Gacyclidine; an antiglutamatergic compound, was also proved to be beneficial in conjunction with atropine, pralidoxime, and diazepam in nerve agent poisoning. Intravenous magnesium sulfate decreased hospitalization duration and improved outcomes in patients with organophosphorous poisoning. Bio-scavengers including fresh frozen plasma or albumin have recently been suggested as a useful therapy through clearing of free organophosphates. Hemofiltration and antioxidants are also suggested for organophosphorous poisoning. Recombinant bacterial phosphotriesterases and hydrolases that are able to transfer organophosphorous-degrading enzymes are very promising in delayed treatment of organophosphorous poisoning. Recently, encapsulation of drugs or enzymes in nanocarriers has also been proposed. Given the signs and symptoms of organophosphorous poisoning, health professionals should remain updated about the recent advances in treatment of organophosphorous poisoning poisonings. PMID:23115436

Therapy against organophosphate poisoning: The importance of anticholinergic drugs with antiglutamatergic properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weissman, Ben Avi; Raveh, Lily

2008-10-15

Potent cholinesterase inhibitors (e.g., soman, sarin), induce a wide range of deleterious effects including convulsions, behavioral impairments and ultimately, death. Due to the likelihood of various scenarios of military or terrorist attacks by these and other chemical weapons, research has to be aimed at finding optimal therapies. Early accumulation of acetylcholine in synaptic clefts was suggested to trigger an array of toxic events including an excessive release of glutamate, culminating in the activation of its receptors. Stimulation of the N-Methyl-D-Aspartate (NMDA) subtype of these receptors was associated with the neuronal injury that initiates organophosphate-induced brain damage. The notion of amore » stepwise mechanism yielded treatments based on a combination of an immediate administration of enzyme reactivators and anticholinergic drugs. This strategy dramatically increased survival rates but did not abolish convulsions and failed to prevent the ensuing cognitive dysfunction. Efforts to improve this paradigm by adding anticonvulsants or antiglutamatergic drugs with anti-epileptic characteristics produced dubious results. Under these conditions, benactyzine and caramiphen, agents with anticholinergic and antiglutamatergic properties, provided improved protection when introduced as adjunct agents to oximes, reversible cholinesterase inhibitors and/or specific antimuscarinic drugs such as atropine. In contrast, the specific antimuscarinic drug scopolamine failed to block soman-induced changes in glutamatergic and behavioral parameters even when given prophylactically. These findings along with a large number of additional reports led towards the conclusion that the therapeutic advantage of drugs such as benactyzine and caramiphen could derive from their ability to modulate central cholinergic and glutamate neurotransmission.« less

Quantum Chemical and Physicochemical Studies of Oximes (Prophylactics against and Reactivators of Phosphorylated AChE).

DTIC Science & Technology

1984-10-25

crystal structure of nicotinic acid ,. and we used the ether bridge from the crystal structure of dimethyl ether. We are investigating various rotamers...observations were made: - The titration curve (after the subtraction of the blank curve) shows only one titrable group, i.e. the oxime moiety. - The...subtraction of the blank curve, shows two titrable groups, i.e. the two oxime moieties. The results are as follows: Temperature Conditions PKa pK2

Efficacy of the Tertiary Oxime Monoisonitrosoacetone (MINA) Against Lethal Sarin Intoxication in the Guinea Pig

DTIC Science & Technology

2007-10-01

Sarin 5a. CONTRACT NUMBER Intoxication in the Guinea Pig 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Koplovitz, I and...efficacy of MINA as a treatment for lethal sarin (GB) intoxication in guinea pigs . Male animals were challenged subcutaneously (s.c.) with 2 LD50s...oximes that are readily able to enter the brain. 15. SUBJECT TERMS oximes, brain, sarin, reactivation, nerve agents, guinea pigs 16. SECURITY

[Comparison of the effects of BI-6, a new asymmetric bipyridine oxime, with HI-6 oxime and obidoxime in combination with atropine on soman and fosdrine toxicity in mice].

PubMed

Kassa, J

1999-01-01

The therapeutic efficacy of the new asymmetric bispyridinium oxime BI-6 against acute toxicity of the highly toxic organophosphate soman and the organophosphorus insecticide fosdrin by means of affecting the LD50 values of these noxiores substances was compared with the effect of the hitherto most perspective oxime HI-6 and the classic obidoxime always in combination with the identical dose of atropine. At the equimolar level the effect of oxime BI-6 against fosdrin completely equals the effects of both oximes HI-6 and obidoxime. The effect of oxime BI-6 against soman is even more marked than the effect of HI-6 but this difference is not statistically significant. On the other hand, at the equi-effective level, the effect of oxime BI-6 against soman is statistically significantly lower than the effect of HI-6, and against fosdrin it is even lower than the effect of both remaining oximes. The effects of the new oxime BI-6 equal, or slightly exceed the therapeutic effect of HI-6 but at the equimolar level only. At the equi-effective level which respects the toxicity of the oxime and is therefore more important for practical use, it is a therapeutically weaker reactivator of acetylcholinesterase than HI-6.

Advances in toxicology and medical treatment of chemical warfare nerve agents

PubMed Central

2012-01-01

Organophosphorous (OP) Nerve agents (NAs) are known as the deadliest chemical warfare agents. They are divided into two classes of G and V agents. Most of them are liquid at room temperature. NAs chemical structures and mechanisms of actions are similar to OP pesticides, but their toxicities are higher than these compounds. The main mechanism of action is irreversible inhibition of Acetyl Choline Esterase (AChE) resulting in accumulation of toxic levels of acetylcholine (ACh) at the synaptic junctions and thus induces muscarinic and nicotinic receptors stimulation. However, other mechanisms have recently been described. Central nervous system (CNS) depression particularly on respiratory and vasomotor centers may induce respiratory failure and cardiac arrest. Intermediate syndrome after NAs exposure is less common than OP pesticides poisoning. There are four approaches to detect exposure to NAs in biological samples: (I) AChE activity measurement, (II) Determination of hydrolysis products in plasma and urine, (III) Fluoride reactivation of phosphylated binding sites and (IV) Mass spectrometric determination of cholinesterase adducts. The clinical manifestations are similar to OP pesticides poisoning, but with more severity and fatalities. The management should be started as soon as possible. The victims should immediately be removed from the field and treatment is commenced with auto-injector antidotes (atropine and oximes) such as MARK I kit. A 0.5% hypochlorite solution as well as novel products like M291 Resin kit, G117H and Phosphotriesterase isolated from soil bacterias, are now available for decontamination of NAs. Atropine and oximes are the well known antidotes that should be infused as clinically indicated. However, some new adjuvant and additional treatment such as magnesium sulfate, sodium bicarbonate, gacyclidine, benactyzine, tezampanel, hemoperfusion, antioxidants and bioscavengers have recently been used for OP NAs poisoning. PMID:23351280

Advances in toxicology and medical treatment of chemical warfare nerve agents.

PubMed

Moshiri, Mohammd; Darchini-Maragheh, Emadodin; Balali-Mood, Mahdi

2012-11-28

Organophosphorous (OP) Nerve agents (NAs) are known as the deadliest chemical warfare agents. They are divided into two classes of G and V agents. Most of them are liquid at room temperature. NAs chemical structures and mechanisms of actions are similar to OP pesticides, but their toxicities are higher than these compounds. The main mechanism of action is irreversible inhibition of Acetyl Choline Esterase (AChE) resulting in accumulation of toxic levels of acetylcholine (ACh) at the synaptic junctions and thus induces muscarinic and nicotinic receptors stimulation. However, other mechanisms have recently been described. Central nervous system (CNS) depression particularly on respiratory and vasomotor centers may induce respiratory failure and cardiac arrest. Intermediate syndrome after NAs exposure is less common than OP pesticides poisoning. There are four approaches to detect exposure to NAs in biological samples: (I) AChE activity measurement, (II) Determination of hydrolysis products in plasma and urine, (III) Fluoride reactivation of phosphylated binding sites and (IV) Mass spectrometric determination of cholinesterase adducts. The clinical manifestations are similar to OP pesticides poisoning, but with more severity and fatalities. The management should be started as soon as possible. The victims should immediately be removed from the field and treatment is commenced with auto-injector antidotes (atropine and oximes) such as MARK I kit. A 0.5% hypochlorite solution as well as novel products like M291 Resin kit, G117H and Phosphotriesterase isolated from soil bacterias, are now available for decontamination of NAs. Atropine and oximes are the well known antidotes that should be infused as clinically indicated. However, some new adjuvant and additional treatment such as magnesium sulfate, sodium bicarbonate, gacyclidine, benactyzine, tezampanel, hemoperfusion, antioxidants and bioscavengers have recently been used for OP NAs poisoning.

Design, evaluation and structure-activity relationship studies of the AChE reactivators against organophosphorus pesticides.

PubMed

Musilek, Kamil; Dolezal, Martin; Gunn-Moore, Frank; Kuca, Kamil

2011-07-01

Organophosphate pesticides (OPPs; e.g. chlorpyrifos, diazinon, paraoxon) are a wide and heterogeneous group of organophosphorus compounds. Their biological activity of inhibiting acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) ranks them as life endangering agents. The necessary treatment after OPP exposure involves the use of parasympatolytics (e.g. atropine), oxime reactivators (e.g. obidoxime), and anticonvulsive drugs (e.g. diazepam). Therefore, the reactivators of AChE are essential compounds in the treatment of OPP intoxications. Commercial AChE reactivators (e.g. pralidoxime, HI-6, obidoxime, trimedoxime, methoxime) were originally developed for other members of the organophosphate family, such as nerve agents (e.g. sarin, soman, tabun, VX). Pralidoxime, HI-6, and methoxime were found to be weak reactivators of OPP-inhibited AChE. Obidoxime and trimedoxime showed satisfactory reactivation against various OPPs with minor toxicity issues. During the last two decades, the treatment of OPP exposure has become more widely discussed because of growing agricultural production, industrialization, and harmful social issues (e.g. suicides). In this review is the summarized design, evaluation, and structure-activity relationship studies of recently produced AChE reactivators. Since pralidoxime, over 300 oximes have been produced or tested against OPP poisoning, and several novel compounds show very promising abilities as comparable (or higher) to commercial oximes. Some of these are highlighted for their further testing of OPP exposure and, additionally, the main structure-activity relationship of AChE reactivators against OPP is discussed. © 2009 Wiley Periodicals, Inc.

Bridged bicyclic systems as acetylcholinesterase reactivators and pretreatment drugs. Annual report, 15 July 1988-14 July 1989

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moriarty, R.M.

1990-03-30

During the past year a large number substituted carbamates, thiocarbamates of various bridged aza bicyclic oximes and their methiodides and meth chlorides have been synthesized. Among these are: (i) O-(N-Substituted carbamoyl)-3-tropinone oxime methiodides and methchlorides, (ii) 0-(N-Substituted carbamoyl)-6-cyano trop-3-ene-2-one oxime methiodides, (iii) O-N-(2`,3`,4`, 6`-Tetra-0-acetyl- b-D-glucopyranosyl thiocarbamoyl)-3-tropinone oxime and its methiodide. Synthesis of 1,6-bis-N`,N`-dimethyl- 3`-oximino-0-carbamoyl tropanonium-N-y1 hexane diiodide and 2,5- bis-(N`N`-dimethyl- 3`-oximino-0-carbamoyl tropanonium-N-yl)-toluene diiodide have been achieved. From phencyclidine a series 4-phenyl-4-0-(N-substituted carbamoyl)-4`-piperidone oxime-1`-yl-1-methyl piperidone methiodides have been synthesized. Syntheses of 0-(N-substituted carbamoyl)-3-exo-dimethyl aminomethyl2-norbornone oximes and their methiodides have been accomplished.

Construction of New Potential Reactivators of Phosphonylated Acetylcholinesterase. Substitution of F for H in the Nucleus of Pyridinecarboxaldehyde Oximes.

DTIC Science & Technology

1982-11-01

interpretation in this report have been entered in typography to insure legibility. 4 u 4A V * i List of Figures Page Fig. la HPLC chromatogram of...crude oximation reaction mixture (4 nMoles) 14 Fig. lb HPLC chromatogram of crude oximation reaction mixture (20 nMoles) 15 Fig. 2a HPLC chromatogram of...of classical organic reactions starting with commercial 2-Amino-4-picoline and progressing to 3-Fluoro-4-picoline. The latter compound was then

Zebrafish as a model for acetylcholinesterase-inhibiting organophosphorus agent exposure and oxime reactivation

PubMed Central

Koenig, Jeffrey A.; Dao, Thuy L.; Kan, Robert K.; Shih, Tsung-Ming

2016-01-01

The current research progression efforts for investigating novel treatments for exposure to organophosphorus (OP) compounds that inhibit acetylcholinesterase (AChE), including pesticides and chemical warfare nerve agents (CWNAs), rely solely on in vitro cell assays and in vivo rodent models. The zebrafish (Danio rerio) is a popular, well-established vertebrate model in biomedical research that offers high-throughput capabilities and genetic manipulation not readily available with rodents. A number of research studies have investigated the effects of subacute developmental exposure to OP pesticides in zebrafish, observing detrimental effects on gross morphology, neuronal development, and behavior. Few studies, however, have utilized this model to evaluate treatments, such as oxime reactivators, anticholinergics, or anticonvulsants, following acute exposure. Preliminary work has investigated the effects of CWNA exposure. The results clearly demonstrated relative toxicity and oxime efficacy similar to that reported for the rodent model. This review surveys the current literature utilizing zebrafish as a model for OP exposure and highlights its potential use as a high-throughput system for evaluating AChE reactivator antidotal treatments to acute pesticide and CWNA exposure. PMID:27123828

[Interest of the cholinesterase assay during organophosphate poisonings].

PubMed

Jalady, A-M; Dorandeu, F

2013-12-01

Cholinesterases are the main targets of organophosphorus compounds. The two enzymes present in the blood (butyrylcholinesterase, BChE; acetylcholinesterase, AChE) are biomarkers of their systemic toxicity. Activity of the plasma BChE is very often determined as it allows a rapid diagnostic of poisoning and is a marker of the persistence of the toxicant in the blood. The activity of the red blood cell AChE gives a better picture of the synaptic inhibition in the nervous system but the assay is less commonly available in routine laboratories. Better biomarker of the exposure, it allows a diagnosis of the severity of the poisoning and helps to assess the efficacy of oxime therapy. Besides the practical aspects of blood collection and sample processing, and the interpretation of the assays, this review stresses the complementarity of both enzyme assays and recalls their crucial interest for the confirmation of poisoning with an organophosphorus in a situation of war or terrorist attack and for the monitoring of occupational exposures. Copyright © 2013. Published by Elsevier SAS.

Comparison of the oxime-induced reactivation of rhesus monkey, swine and guinea pig erythrocyte acetylcholinesterase following inhibition by sarin or paraoxon, using a perfusion model for the real-time determination of membrane-bound acetylcholinesterase activity.

PubMed

Herkert, Nadja M; Lallement, Guy; Clarençon, Didier; Thiermann, Horst; Worek, Franz

2009-04-28

Recently, a dynamically working in vitro model with real-time determination of membrane-bound human acetylcholinesterase (AChE) activity was shown to be a versatile model to investigate oxime-induced reactivation kinetics of organophosphate- (OP) inhibited enzyme. In this assay, AChE was immobilized on particle filters which were perfused with acetylthiocholine, Ellman's reagent and phosphate buffer. Subsequently, AChE activity was continuously analyzed in a flow-through detector. Now, it was an intriguing question whether this model could be used with erythrocyte AChE from other species in order to investigate kinetic interactions in the absence of annoying side reactions. Rhesus monkey, swine and guinea pig erythrocytes were a stable and highly reproducible enzyme source. Then, the model was applied to the reactivation of sarin- and paraoxon-inhibited AChE by obidoxime or HI 6 and it could be shown that the derived reactivation rate constants were in good agreement to previous results obtained from experiments with a static model. Hence, this dynamic model offers the possibility to investigate highly reproducible interactions between AChE, OP and oximes with human and animal AChE.

Comparison of human and guinea pig acetylcholinesterase sequences and rates of oxime-assisted reactivation.

PubMed

Cadieux, C Linn; Broomfield, Clarence A; Kirkpatrick, Melanie G; Kazanski, Meghan E; Lenz, David E; Cerasoli, Douglas M

2010-09-06

Poisoning via organophosphorus (OP) nerve agents occurs when the OP binds and inhibits the enzyme acetylcholinesterase (AChE). This enzyme is responsible for the metabolism of the neurotransmitter acetylcholine (ACh) which transmits signals between nerves and several key somatic regions. When AChE is inhibited, the signal initiated by ACh is not properly terminated. Excessive levels of ACh result in a cholinergic crisis, and in severe cases can lead to death. Current treatments for OP poisoning involve the administration of atropine, which blocks ACh receptors, and oximes, which reactivate AChE after inhibition. Efforts to improve the safety, efficacy, and broad spectrum utility of these treatments are ongoing and usually require the use of appropriate animal model systems. For OP poisoning, the guinea pig (Cavia porcellus) is a commonly used animal model because guinea pigs more closely mirror primate susceptibility to OP poisoning than do other animals such as rats and mice. This is most likely because among rodents and other small mammals, guinea pigs have a very low relative concentration of serum carboxylesterase, an enzyme known to bind OPs in vitro and to act as an endogenous bioscavenger in vivo. Although guinea pigs historically have been used to test OP poisoning therapies, it has been found recently that guinea pig AChE is substantially more resistant to oxime-mediated reactivation than human AChE. To examine the molecular basis for this difference, we reverse transcribed mRNA encoding guinea pig AChE, amplified the resulting cDNA, and sequenced this product. The nucleotide and deduced amino acid sequences of guinea pig AChE were then compared to the human version. Several amino acid differences were noted, and the predicted locations of these differences were mapped onto a structural model of human AChE. To examine directly how these differences affect oxime-mediated reactivation of AChE after inhibition by OPs, human and guinea pig red blood cell ghosts were prepared and used as sources of AChE, and the relative capacity of several different oximes to reactivate each OP-inhibited AChE were determined. The differences we report between human and guinea pig AChE raise additional concerns about the suitability of the guinea pig as an appropriate small animal model to approximate human responses to OP poisoning and therapies. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

The history of cholinesterase reactivation: hydroxylamine and pyridinium aldoximes.

PubMed

Petroianu, G A

2012-10-01

Hydroxylamine (NH2OH) the substance which will turn out to be of importance to those interested in the treatment of organophosporus cholinesterase inhibitor exposure, was synthesized by Wilhem Clemens Lossen in 1865 while working in Halle as an assistant in the laboratory of Wilhelm Heinrich Heintz. The Lossen synthesis generated hydroxylamine in aqueous solution. Anhydrous hydroxylamine was prepared almost simultaneously by Lobry de Bruyn and Crismer (1891). Using hydroxylamine as a starting point Meyer synthesized aldoximes and ketoximes (1897). Lange, a PhD student of Ladenburg, isolated 2-methyl-pyridine (alpha-picoline). Some fifty years later Wilson, working in the laboratory of Nachmansohn, demonstrated the ability of hydroxylamine to reactivate cholinesterase inhibited by organophosphates. Finally Wilson and Ginsburg using 2-methyl-pyridine as a starting point synthesized the first pyridinium aldoxime reactivator of clinical relevance, pralidoxime (1955).

Possible long-term health effects of short-term exposure to chemical agents. Volume 2. Cholinesterase reactivators, psychochemicals, and irritants and vesicants. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1984-01-01

The present report evaluates toxicologic and epidemiologic data relevant to the testing of approximately 750 subjects exposed to cholinesterase reactivators, about 260 exposed to psychochemicals, and 1,500 exposed to irritants or vesicants. A remaining group of subjects used largely in tests involving placebo or innocuous chemicals or conditions is available for comparison and will be discussed later. The report is the work of three panels of scientists--the Panel on Cholinesterase Reactivator Chemicals, the Panel on Psychochemicals, and the Panel on Irritants and Vesicants. The chairman of each panel was selected from the Committee on Toxicology, and the members were selectedmore » on the basis of their knowledge of the compounds in question or because they represented required disciplines.« less

Plasma esterases in the tegu lizard Tupinambis merianae (Reptilia, Teiidae): impact of developmental stage, sex, and organophosphorus in vitro exposure.

PubMed

Basso, Agustín; Attademo, Andrés M; Lajmanovich, Rafael C; Peltzer, Paola M; Junges, Celina; Cabagna, Mariana C; Fiorenza, Gabriela S; Sanchez-Hernandez, Juan Carlos

2012-01-01

In this study, we determined normal serum butyrylcholinesterase (BChE) and carboxylesterase (CbE) activities in Tupinambis merianae in order to obtain reference values for organophosphorus pesticide monitoring. Forty-two T. merianae individuals were grouped by sex and size to identify potential differences in their enzyme levels to allow for proper representation of normal values for females, males, juveniles, and hatchlings. Mean CbE was determined using two model substrates: alpha-naphtylacetate (α-NA) and p-nitrophenyl valerate (4-NPV). BChE and CbE sensitivity to malaoxon (Mx) was also evaluated as well as the possibility of BChE reactivation with pyridine-2-aldoxime methochloride (2-PAM). Mean adult females' BChE was significantly higher than adult males, juveniles, and hatchlings. No significant differences were found between groups regarding CbE. CbE (4-NPV) activity showed slightly negative correlation with lizard snout-vent length, while BChE and CbE (α-NA) showed no correlation with body size. Apparent IC(50) values for BChE and CbE (α-NA) suggested different sensitivities among groups. CbE (4-NPV) could not be inhibited. All Mx-inhibited groups treated with 2-PAM in a final concentration of 2.8 mM showed clear signs of reactivation. In conclusion, the results demonstrate that (1) plasma esterase activity did not vary with age and sex, except for BChE activity, and (2) because biological and environmental variables could be confounding factors in the response of plasma cholinesterases, complementary biomarkers like CbE inhibition and oxime-induced reactivation of esterases are strongly recommended.

Revealing the importance of linkers in K-series oxime reactivators for tabun-inhibited AChE using quantum chemical, docking and SMD studies

NASA Astrophysics Data System (ADS)

Ghosh, Shibaji; Chandar, Nellore Bhanu; Jana, Kalyanashis; Ganguly, Bishwajit

2017-08-01

Inhibition of acetylcholinesterase (AChE) with organophosphorus compounds has a detrimental effect on human life. Oxime K203 seems to be one of the promising reactivators for tabun-inhibited AChE than (K027, K127, and K628). These reactivators differ only in the linker units between the two pyridinium rings. The conformational analyses performed with quantum chemical RHF/6-31G* level for K027, K127, K203 and K628 showed that the minimum energy conformers have different orientations of the active and peripheral pyridinium rings for these reactivator molecules. K203 with (-CH2-CH=CH-CH2-) linker unit possesses more open conformation compared to the other reactivators. Such orientation of K203 experiences favorable interaction with the surrounding residues of catalytic anionic site (CAS) and peripheral anionic site (PAS) of tabun-inhibited AChE. From the steered molecular dynamics simulations, it has been observed that the oxygen atom of the oxime group of K203 reactivator approaches nearest to the P-atom of the SUN203 (3.75 Å) at lower time scales (less than 1000 ps) as compared to the other reactivators. K203 experiences less number of hydrophobic interaction with the PAS residues which is suggested to be an important factor for the efficient reactivation process. In addition, K203 crates large number of H-bonding with CAS residues SUN203, Phe295, Tyr337, Phe338 and His447. K203 barely changes its conformation during the SMD simulation process and hence the energy penalty to adopt any other conformation is minimal in this case as compared to the other reactivators. The molecular mechanics and Poisson-Boltzmann surface area binding energies obtained for the interaction of K203 inside the gorge of tabun inhibited AChE is substantially higher (-290.2 kcal/mol) than the corresponding K628 reactivator (-260.4 kcal/mol), which also possess unsaturated aromatic linker unit.

The kinetics of inhibition of erythrocyte cholinesterase by monomethylcarbamates

PubMed Central

Reiner, E.; Simeon-Rudolf, V.

1966-01-01

1. The kinetics of the interaction of erythrocyte cholinesterase with 1-naphthyl N-methylcarbamate, 2-isopropoxyphenyl N-methylcarbamate and phenyl N-methylcarbamate were studied. Rate constants for inhibition and rate constants for spontaneous reactivation were determined. The calculated rate constants for spontaneous reactivation agreed well with those obtained experimentally. 2. The degree of inhibition obtained after preincubation of enzyme and inhibitor was found to be independent of both the substrate concentration and the dilution of the inhibited enzyme. 3. The reaction between the enzyme and the inhibitor was consistent with carbamates being regarded as poor substrates of cholinesterases. There was no evidence for the formation of a reversible complex between the enzyme and the carbamate. PMID:5941343

Study of Inhibition, Reactivation and Aging Processes of Pesticides Using Graphene Nanosheets/Gold Nanoparticles-Based Acetylcholinesterase Biosensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Lin; Long, Linjuan; Zhang, Weiying

2012-09-10

Organophosphate (OP) and carbamate pesticides exert their toxicity via attacking the hydroxyl moiety of serine in the 'active site' of acetylcholinesterase (AChE). In this paper we developed a stable AChE biosensor based on self-assembling AChE to graphene nanosheet (GN)-gold nanoparticles (AuNPs) nanocomposite electrode for investigation of inhibition, reactivation and aging processes of different pesticides. It is confirmed that pesticides can inhibit AChE in a short time. OPs poisoning is treatable with oximes while carbarmates exposure is insensitive to oximes. The proposed electrochemical approach thus provides a new simple tool for comparison of pesticide sensitivity and guide of therapeutic intervention.

Central Acetylcholinesterase Reactivation by Oximes Improves Survival and Terminates Seizures Following Nerve Agent Intoxication

DTIC Science & Technology

2009-01-01

activity ; GB = sarin; im = intramuscular; ip = intraperitoneal; LD50 = median lethal dose 50%; MINA = monoisonitrosoacetone; MMB-4 = methoxime; OP...inhibited acetylcholinesterase (AChE) activity . We have studied the capability of the tertiary oximes monoisonitrosoacetone (MINA) and diacetylmonoxime...of 20, 26, 35, 46 and 60 mg/kg, there were 0, 9, 17, 60, and 75%, respectively, of animals never exhibited EEG seizure activity with 43, 64, 75, 90

Theoretical NMR and conformational analysis of solvated oximes for organophosphates-inhibited acetylcholinesterase reactivation

NASA Astrophysics Data System (ADS)

da Silva, Jorge Alberto Valle; Modesto-Costa, Lucas; de Koning, Martijn C.; Borges, Itamar; França, Tanos Celmar Costa

2018-01-01

In this work, quaternary and non-quaternary oximes designed to bind at the peripheral site of acetylcholinesterase previously inhibited by organophosphates were investigated theoretically. Some of those oximes have a large number of degrees of freedom, thus requiring an accurate method to obtain molecular geometries. For this reason, the density functional theory (DFT) was employed to refine their molecular geometries after conformational analysis and to compare their 1H and 13C nuclear magnetic resonance (NMR) theoretical signals in gas-phase and in solvent. A good agreement with experimental data was achieved and the same theoretical approach was employed to obtain the geometries in water environment for further studies.

Mono-oxime bisquaternary acetylcholinesterase reactivators with prop-1,3-diyl linkage-Preparation, in vitro screening and molecular docking.

PubMed

Musilek, Kamil; Komloova, Marketa; Holas, Ondrej; Horova, Anna; Pohanka, Miroslav; Gunn-Moore, Frank; Dohnal, Vlastimil; Dolezal, Martin; Kuca, Kamil

2011-01-15

The treatment of organophosphorus (OP) poisoning consists of the administration of a parasympatholytic agent (e.g., atropine), an anticonvulsant (e.g., diazepam) and an acetylcholinesterase (AChE) reactivator (e.g., obidoxime). The AChE reactivator is the causal treatment of OP exposure, because it cleaves the OP moiety covalently bound to the AChE active site. In this paper, fourteen novel AChE reactivators are described. Their design originated from a former promising compound K027. These compounds were synthesized, evaluated in vitro on human AChE (hAChE) inhibited by tabun, paraoxon, methylparaoxon and DFP and then compared to commercial hAChE reactivators (pralidoxime, HI-6, trimedoxime, obidoxime, methoxime) or previously prepared compounds (K027, K203). Three of these novel compounds showed a promising ability to reactivate hAChE comparable or better than the used standards. Consequently, a molecular docking study was performed for three of these promising novel compounds. The docking results confirmed the apparent influence of π-π or cation-π interactions and hydrogen bonding for reactivator binding within the hAChE active site cleft. The SAR features concerning the non-oxime part of the reactivator molecule are also discussed. Copyright © 2010 Elsevier Ltd. All rights reserved.

Construction of New Potential Reactivators of Phosphonylated Acetylcholinesterase. Substitution of F for H in the Nucleus of Pyridinecarboxaldehyde Oximes.

DTIC Science & Technology

1983-11-01

essential to the content of the re- port and in all cases NMR data subjected to interpretation in this report have been entered in typography to...compared. In the Second Quarter reactions in the synthetic pathway to 3-F-2-PAM were scaled-up. Low yields were encountered for the specific nitration...oxime was synthetically achieved by way of the Markovac-Stevens-Ash-Hackley reaction , and the compound was characterized by its mass spectrum, NMR

Revealing the importance of linkers in K-series oxime reactivators for tabun-inhibited AChE using quantum chemical, docking and SMD studies.

PubMed

Ghosh, Shibaji; Chandar, Nellore Bhanu; Jana, Kalyanashis; Ganguly, Bishwajit

2017-08-01

Inhibition of acetylcholinesterase (AChE) with organophosphorus compounds has a detrimental effect on human life. Oxime K203 seems to be one of the promising reactivators for tabun-inhibited AChE than (K027, K127, and K628). These reactivators differ only in the linker units between the two pyridinium rings. The conformational analyses performed with quantum chemical RHF/6-31G* level for K027, K127, K203 and K628 showed that the minimum energy conformers have different orientations of the active and peripheral pyridinium rings for these reactivator molecules. K203 with (-CH 2 -CH=CH-CH 2 -) linker unit possesses more open conformation compared to the other reactivators. Such orientation of K203 experiences favorable interaction with the surrounding residues of catalytic anionic site (CAS) and peripheral anionic site (PAS) of tabun-inhibited AChE. From the steered molecular dynamics simulations, it has been observed that the oxygen atom of the oxime group of K203 reactivator approaches nearest to the P-atom of the SUN203 (3.75 Å) at lower time scales (less than ~1000 ps) as compared to the other reactivators. K203 experiences less number of hydrophobic interaction with the PAS residues which is suggested to be an important factor for the efficient reactivation process. In addition, K203 crates large number of H-bonding with CAS residues SUN203, Phe295, Tyr337, Phe338 and His447. K203 barely changes its conformation during the SMD simulation process and hence the energy penalty to adopt any other conformation is minimal in this case as compared to the other reactivators. The molecular mechanics and Poisson-Boltzmann surface area binding energies obtained for the interaction of K203 inside the gorge of tabun inhibited AChE is substantially higher (-290.2 kcal/mol) than the corresponding K628 reactivator (-260.4 kcal/mol), which also possess unsaturated aromatic linker unit.

Limitations and challenges in treatment of acute chemical warfare agent poisoning.

PubMed

Thiermann, Horst; Worek, Franz; Kehe, Kai

2013-12-05

Recent news from Syria on a possible use of chemical warfare agents made the headlines. Furthermore, the motivation of terrorists to cause maximal harm shifts these agents into the public focus. For incidents with mass casualties appropriate medical countermeasures must be available. At present, the most important threats arise from nerve agents and sulfur mustard. At first, self-protection and protection of medical units from contamination is of utmost importance. Volatile nerve agent exposure, e.g. sarin, results in fast development of cholinergic crisis. Immediate clinical diagnosis can be confirmed on-site by assessment of acetylcholinesterase activity. Treatment with autoinjectors that are filled with 2mg atropine and an oxime (at present obidoxime, pralidoxime, TMB-4 or HI-6) are not effective against all nerve agents. A more aggressive atropinisation has to be considered and more effective oximes (if possible with a broad spectrum or a combination of different oximes) as well as alternative strategies to cope with high acetylcholine levels at synaptic sites should be developed. A further gap exists for the treatment of patients with sustained cholinergic crisis that has to be expected after exposure to persistent nerve agents, e.g. VX. The requirement for long-lasting artificial ventilation can be reduced with an oxime therapy that is optimized by using the cholinesterase status for guidance or by measures (e.g. scavengers) that are able to reduce the poison load substantially in the patients. For sulfur mustard poisoning no specific antidote is available until now. Symptomatic measures as used for treatment of burns are recommended together with surgical or laser debridement. Thus, huge amounts of resources are expected to be consumed as wound healing is impaired. Possible depots of sulfur mustard in tissues may aggravate the situation. More basic knowledge is necessary to improve substantially therapeutic options. The use of stem cells may provide a new and promising option. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor.

PubMed

Munirathinam, Rajesh; Ricciardi, Roberto; Egberink, Richard J M; Huskens, Jurriaan; Holtkamp, Michael; Wormeester, Herbert; Karst, Uwe; Verboom, Willem

2013-01-01

Polystyrene sulfonate polymer brushes, grown on the interior of the microchannels in a microreactor, have been used for the anchoring of gallium as a Lewis acid catalyst. Initially, gallium-containing polymer brushes were grown on a flat silicon oxide surface and were characterized by FTIR, ellipsometry, and X-ray photoelectron spectroscopy (XPS). XPS revealed the presence of one gallium per 2-3 styrene sulfonate groups of the polymer brushes. The catalytic activity of the Lewis acid-functionalized brushes in a microreactor was demonstrated for the dehydration of oximes, using cinnamaldehyde oxime as a model substrate, and for the formation of oxazoles by ring closure of ortho-hydroxy oximes. The catalytic activity of the microreactor could be maintained by periodic reactivation by treatment with GaCl3.

Health Aspects of Organophosphorous Pesticides in Asian Countries

PubMed Central

Balali-Mood, M; Balali-Mood, K; Moodi, M; Balali-Mood, B

2012-01-01

Organophosphorous (OP) pesticides are used frequently in agriculture, particularly in Asian countries over the past decades. Poisoning by these agents, either as acute or chronic in these nations, is a serious health problem. OP pesticides residue in fruits and vegetables that may not induce early clinical features, could also affect the human health. Therefore, medical and health professionals should be aware and learn more on the toxicology, prevention and proper management of OP poisoning. The well-known mechanism of OP toxicity is the inhibition of acetyl cholinesterase, resulting in an accumulation of acetylcholine and continued stimulation of acetylcholine receptors. Therefore, they are also called anticholinesterase agents. Determination of blood acetyl cholinesterase and butyryl cholinesterase activities remains a mainstay for the rapid initial screening of OP pesticides. Quantitative analysis of OP and their degradation products in plasma and urine by mass spectrometric methods is a more specific method, but is expensive and limited to specialized laboratories. Therefore, history of OP pesticides exposure and clinical manifestations of a cholinergic syndrome is sufficient for management of the exposed patients. However, electrophysiological tests may be required for the diagnosis of delayed neuropathy of OP poisoning. The standard management of OP poisoning includes decontamination, atropine sulphate with an oxime. Recent advances focus on blood alkalinisation and magnesium sulphate as promising adjunctive therapies. Preventive measures in OP exposure are of great importance in human health in developing countries. Therefore, regulations and controls on safe use of OP particularly in Asian countries are recommended. PMID:23304659

Chemoselective amide formation using O-(4-nitrophenyl)hydroxylamines and pyruvic acid derivatives.

PubMed

Kumar, Sonali; Sharma, Rashi; Garcia, Megan; Kamel, Joseph; McCarthy, Caroline; Muth, Aaron; Phanstiel, Otto

2012-12-07

A series of O-(4-nitrophenyl)hydroxylamines were synthesized from their respective oximes using a pulsed addition of excess NaBH(3)CN at pH 3 in 65-75% yield. Steric hindrance near the oxime functional group played a key role in both the ease by which the oxime could be reduced and the subsequent reactivity of the respective hydroxylamine. Reaction of the respective hydroxylamines with pyruvic acid derivatives generated the desired amides in good yields. A comparison of phenethylamine systems bearing different leaving groups revealed significant differences in the rates of these systems and suggested that the leaving group ability of the N-OR substituent plays an important role in determining their reactivity with pyruvic acid. Competition experiments (in 68% DMSO/phosphate buffered saline) using 1 equiv of N-phenethyl-O-(4-nitrophenyl)hydroxylamine and 2 equiv of pyruvic acid in the presence of other nucleophiles such as glycine, cysteine, phenol, hexanoic acid, and lysine demonstrated that significant chemoselectivity is present in this reaction. The results suggest that this chemoselective reaction can occur in the presence of excess α-amino acids, phenols, acids, thiols, and amines.

Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor

PubMed Central

Munirathinam, Rajesh; Ricciardi, Roberto; Egberink, Richard J M; Huskens, Jurriaan; Holtkamp, Michael; Wormeester, Herbert; Karst, Uwe

2013-01-01

Summary Polystyrene sulfonate polymer brushes, grown on the interior of the microchannels in a microreactor, have been used for the anchoring of gallium as a Lewis acid catalyst. Initially, gallium-containing polymer brushes were grown on a flat silicon oxide surface and were characterized by FTIR, ellipsometry, and X-ray photoelectron spectroscopy (XPS). XPS revealed the presence of one gallium per 2–3 styrene sulfonate groups of the polymer brushes. The catalytic activity of the Lewis acid-functionalized brushes in a microreactor was demonstrated for the dehydration of oximes, using cinnamaldehyde oxime as a model substrate, and for the formation of oxazoles by ring closure of ortho-hydroxy oximes. The catalytic activity of the microreactor could be maintained by periodic reactivation by treatment with GaCl3. PMID:24062830

Genetic toxicology assessment of HI-6 dichloride

DOE Office of Scientific and Technical Information (OSTI.GOV)

Putman, D.; San, R.H.; Bigger, C.A.

1996-08-01

The oxime HI-6 dichloride (1-(2 hydroxyiminomethyl- 1-pyridino)-3- (4-carbamoyl-1- pyridino)-2-oxapropane dichloride monohydrate) has shown to be a potent reactivator of cholinesterase activity and may have efficacy for the treatment of organo-phosphate intoxication (SIPRI, 1976; Schenk et al.; Arch Toxicol 36:71-81, 1976). As part of a pre-clinical safety assessment program, the genetic toxicology of HI-6 dichloride was evaluated in a series of assays designed to measure induction of gene mutations and chromosomal aberrations. HI-6 dichloride gave negative responses in the Salmonella mutagenicity assay and in the CHO/HGPRT gene mutation assay. Dose-dependent increases in the frequency of chromosomal aberrations when HI-6 dichloride wasmore » tested in cultured CHO cells and in cultured human peripheral blood lymphocytes. The mouse lymphoma gene mutation assay, reputed to measure both gene mutations and chromosomal deletions, was negative in the absence of metabolic activation. Depending on the criteria employed, a negative or equivocal response was seen in the presence of rat liver-derived S-9 mix. An in vivo rat bone marrow metaphase assay performed to further investigate the in vitro clastogenic responses was negative. The results from these studies indicate that HI-6 dichloride does not induce gene mutations in vitro; however, it is clastogenic in vitro but does not appear to be clastogenic in vivo.« less

Interaction of cholinesterase modulators with DNA and their cytotoxic activity.

PubMed

Janockova, Jana; Gulasova, Zuzana; Plsikova, Jana; Musilek, Kamil; Kuca, Kamil; Mikes, Jaromir; Culka, Lubomir; Fedorocko, Peter; Kozurkova, Maria

2014-03-01

This research was focused on a study of the binding properties of a series of cholinesterase reactivators compounds K075 (1), K027 (2) and inhibitors compounds K524, K009 and 7-MEOTA (3-5) with calf thymus DNA. The nature of the interactions between compounds 1-5 and DNA were studied using spectroscopic techniques (UV-vis, fluorescence spectroscopy and circular dichroism). The binding constants for complexes of cholinesterase modulators with DNA were determined from UV-vis spectroscopic titrations (K=0.5 × 10(4)-8.9 × 10(5)M(-1)). The ability of the prepared analogues to relax topoisomerase I was studied with electrophoretic techniques and it was proved that ligands 4 and 5 inhibited this enzyme at a concentration of 30 μM. The biological activity of the novel compounds was assessed through an examination of changes in cell cycle distribution, mitochondrial membrane potential and cellular viability. Inhibitors 3-5 exhibited a cytotoxic effect on HL-60 (human acute promyelocytic leukaemia) cell culture, demonstrated a tendency to affect mitochondrial physiology and viability, and also forced cells to accumulate in the G1/G0-phase of the cell cycle. The cholinesterase reactivators 1 and 2 were found relatively save from the point of view of DNA binding, whereas cholinesterase inhibitors 3-5 resulted as strong DNA binding agents that limit their plausible use. Copyright © 2013 Elsevier B.V. All rights reserved.

Bioscavengers for the protection of humans against organophosphate toxicity.

PubMed

Doctor, Bhupendra P; Saxena, Ashima

2005-12-15

Current antidotes for organophosphorus compounds (OP) poisoning consist of a combination of pretreatment with carbamates (pyridostigmine bromide), to protect acetylcholinesterase (AChE) from irreversible inhibition by OP compounds, and post-exposure therapy with anti-cholinergic drugs (atropine sulfate) to counteract the effects of excess acetylcholine and oximes (e.g., 2-PAM chloride) to reactivate OP-inhibited AChE. These antidotes are effective in preventing lethality from OP poisoning, but they do not prevent post-exposure incapacitation, convulsions, seizures, performance decrements, or in many cases permanent brain damage. These symptoms are commonly observed in experimental animals and are likely to occur in humans. The problems intrinsic to these antidotes stimulated attempts to develop a single protective drug, itself devoid of pharmacological effects, which would provide protection against the lethality of OP compounds and prevent post-exposure incapacitation. One approach is the use of enzymes such as cholinesterases (ChEs), beta-esterases in general, as single pretreatment drugs to sequester highly toxic OP anti-ChEs before they reach their physiological targets. This approach turns the irreversible nature of the OP: ChE interaction from disadvantage to an advantage; instead of focusing on OP as an anti-ChE, one can use ChE as an anti-OP. Using this approach, it was shown that administration of fetal bovine serum AChE (FBSAChE) or equine serum butyrylcholinesterase (EqBChE) or human serum BChE (HuBChE) protected the animals from multiple LD50s of a variety of highly toxic OPs without any toxic effects or performance decrements. The bioscavengers that have been explored to date for the detoxification of OPs fall into three categories: (A) those that can catalytically hydrolyze OPs and thus render them non-toxic, such as OP hydrolase and OP anhydrase; (B) those that stoichiometrically bind to OPs, that is, 1 mol of enzyme neutralizes one or 2 mol of OP inactivating both, such as ChEs and related enzymes; and (C) and those generally termed as "pseudo catalytic", e.g., a combination of ChE and an oxime pre-treatment such that the catalytic activity of OP-inhibited ChE can rapidly and continuously be restored in the presence of an oxime. Since the biochemical mechanism underlying prophylaxis by exogenous esterases such as ChEs is established and tested in several animal species, including non-human primates, this concept should allow a reliable extrapolation of results from animal experiments to human application. Having being extensively investigated by several groups, plasma derived HuBChE is judged to be the most suitable bioscavenger for its advancement for human use. The program is being developed at the present time for conducting a safety clinical trial in human volunteers. Several other candidate bioscavengers will follow; e.g., recombinant HuBChE expressed in the milk of transgenic goats, pseudo catalytic scavenger(s), e.g., a combination of ChE and oxime, and possibly PON 1 as a catalytic scavenger in the future.

[COMPARATIVE SENSITIVITY OF CHOLINESTERASES IN VERTEBRATES AND INVERTEBRATES TO HIGHLY SPECIFIC ORGANOPHOSPHORUS INHIBITORS DIISOPROPYL FLUOROPHOSPHATE (DFP) AND (2-ETHOXYMETHYL PHOSPHORYL THIOETHYL) ETHYL (METHYL) SULPHONIUM SULPHOMETHYLAT (GD-42)].

PubMed

Basova, N E; Kormilitsyn, B N; Perchenok, A Yu; Rozengart, E V; Saakov, V S; Suvorov, A A

2015-01-01

The review presents data on comparative reactivity of 68 cholinesterase preparation from various organs and tissues in a number of vertebrates and invertebrates based on sensitivity to two highly specific and most studied organophosphorus inhibitors--diisopropyl fluorophosphates (DFP) and (2-ethoxymethyl phosphoryl thioethyl) ethyl (methyl) sulphonium sulphomethylat (GD-42). Analysis of these data suggests a great diversity in enzymologic characteristics of cholinesterase preparation in representatives of vertebrates and invertebrates, this variety observed even for closely related enzymes in animals of almost the same level of development.

Exposure of nonbreeding migratory shorebirds to cholinesterase-inhibiting contaminants in the western hemisphere

USGS Publications Warehouse

Strum, K.M.; Hooper, M.J.; Johnson, K.A.; Lanctot, Richard B.; Zaccagnini, M.E.; Sandercock, B.K.

2010-01-01

Migratory shorebirds frequently forage and roost in agricultural habitats, where they may be exposed to cholinesterase-inhibiting pesticides. Exposure to organophosphorus and carbamate compounds, common anti-cholinesterases, can cause sublethal effects, even death. To evaluate exposure of migratory shorebirds to organophosphorus and carbamates, we sampled birds stopping over during migration in North America and wintering in South America. We compared plasma cholinesterase activities and body masses of individuals captured at sites with no known sources of organophosphorus or carbamates to those captured in agricultural areas where agrochemicals were recommended for control of crop pests. In South America, plasma acetylcholinesterase and butyrylcholinesterase activity in Buff-breasted Sandpipers was lower at agricultural sites than at reference sites, indicating exposure to organophosphorus and carbamates. Results of plasma cholinesterase reactivation assays and foot-wash analyses were inconclusive. A meta-analysis of six species revealed no widespread effect of agricultural chemicals on cholinesterase activity. however, four of six species were negative for acetylcholinesterase and one of six for butyrylcholinesterase, indicating negative effects of pesticides on cholinesterase activity in a subset of shorebirds. Exposure to cholinesterase inhibitors can decrease body mass, but comparisons between treatments and hemispheres suggest that agrochemicals did not affect migratory shorebirds' body mass. Our study, one of the first to estimate of shorebirds' exposure to cholinesterase-inhibiting pesticides, suggests that shorebirds are being exposed to cholinesterase- inhibiting pesticides at specific sites in the winter range but not at migratory stopover sites. future research should examine potential behavioral effects of exposure and identify other potential sitesand levels of exposure. ?? The Cooper Ornithological Society 2010.

Catalytic soman scavenging by Y337A/F338A acetylcholinesterase mutant assisted with novel site-directed aldoximes

PubMed Central

Kovarik, Zrinka; Hrvat, Nikolina Maček; Katalinić, Maja; Sit, Rakesh K.; Paradyse, Alexander; Žunec, Suzana; Musilek, Kamil; Fokin, Valery V.; Taylor, Palmer; Radić, Zoran

2016-01-01

Exposure to the nerve agent soman is difficult to treat due to the rapid dealkylation of soman-acetylcholinesterase (AChE) conjugate known as aging. Oxime antidotes commonly used to reactivate organophosphate inhibited AChE are ineffective against soman, while the efficacy of the recommended nerve agent bioscavenger butyrylcholinesterase is limited by strictly stoichiometric scavenging. To overcome this limitation, we tested ex vivo, in human blood, and in vivo, in soman exposed mice, the capacity of aging-resistant human AChE mutant Y337A/F338A in combination with oxime HI-6 to act as a catalytic bioscavenger of soman. HI-6 was previously shown in vitro to efficiently reactivate this mutant upon soman, as well as VX, cyclosarin, sarin and paraoxon inhibition. We here demonstrate that ex vivo, in whole human blood, 1 μM soman was detoxified within 30 minutes when supplemented with 0.5 μM Y337A/F338A AChE and 100 μM HI-6. This combination was further tested in vivo. Catalytic scavenging of soman in mice improved the therapeutic outcome and resulted in the delayed onset of toxicity symptoms. Furthermore, in a preliminary in vitro screen we identified an even more efficacious oxime than HI-6, in a series of forty-two pyridinium aldoximes, and five imidazole 2-aldoxime N-propyl pyridinium derivatives. One of the later imidazole aldoximes, RS-170B, was a 2–3 –fold more effective reactivator of Y337A/F338A AChE than HI-6 due to the smaller imidazole ring, as indicated by computational molecular models, that affords a more productive angle of nucleophilic attack. PMID:25835984

Acute organophosphorus poisoning complicated by acute coronary syndrome.

PubMed

Pankaj, Madhu; Krishna, Kavita

2014-07-01

We report a case of 30 year old alcoholic male admitted with vomiting, drowsiness, limb weakness and fasciculations after alleged history of consumption of 30 ml of chlorpyriphos insecticide. He had low serum cholinesterase levels. With standard treatment for organophosphorus poisoning (OPP), he improved gradually until day 5, when he developed neck and limb weakness and respiratory distress. This intermediate syndrome was treated with oximes, atropine and artificial ventilation. During treatment, his ECG showed fresh changes of ST elevation. High CPK & CPK-MB levels, septal hypokinesia on 2D echo suggested acute coronary syndrome. Coronary angiography was postponed due to his bedridden and obtunded status. The patient finally recovered fully by day 15 and was discharged. Acute coronary syndrome is a rare occurrence in OP poisoning. The present case thus emphasises the need for careful electrocardiographic and enzymatic monitoring of all patients of organophosphorus poisoning to prevent potential cardiac complication which can prove fatal.

Distribution of sup 125 I-neurotensin binding sites in human forebrain: Comparison with the localization of acetylcholinesterase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szigethy, E.; Quirion, R.; Beaudet, A.

1990-07-22

The distribution of 125I-neurotensin binding sites was compared with that of acetylcholinesterase reactivity in the human basal forebrain by using combined light microscopic radioautography/histochemistry. High 125I-neurotensin binding densities were observed in the bed nucleus of the stria terminalis, islands of Calleja, claustrum, olfactory tubercle, and central nucleus of the amygdala; lower levels were seen in the caudate, putamen, medial septum, diagonal band nucleus, and nucleus basalis of Meynert. Adjacent sections processed for cholinesterase histochemistry demonstrated a regional overlap between the distribution of labeled neurotensin binding sites and that of intense acetylcholinesterase staining in all of the above regions, except inmore » the bed nucleus of the stria terminalis, claustrum, and central amygdaloid nucleus, where dense 125I-neurotensin labeling was detected over areas containing only weak to moderate cholinesterase staining. At higher magnification, 125I-neurotensin-labeled binding sites in the islands of Calleja, supraoptic nucleus of the hypothalamus, medial septum, diagonal band nucleus, and nucleus basalis of Meynert were selectively associated with neuronal perikarya found to be cholinesterase-positive in adjacent sections. Moderate 125I-neurotensin binding was also apparent over the cholinesterase-reactive neuropil of these latter three regions. These data suggest that neurotensin (NT) may directly influence the activity of magnocellular cholinergic neurons in the human basal forebrain, and may be involved in the physiopathology of dementing disorders such as Alzheimer's disease, in which these neurons have been shown to be affected.« less

COMPARISON BETWEEN ELLMAN AND RADIOMETRIC METHODS FOR ASSESSING CHOLINESTERASE (CHE) INHIBITION IN RATS TREATED WITH N-METHYL CARBAMATE INSECTICIDES.

EPA Science Inventory

Carbamylated ChE is unstable and readily reactivates. This reactivation, promoted by increasing temperature and dilution, could have an impact on ex vivo ChE assays by decreasing apparent ChE inhibition. To assess the best method for measuring ChE inhibition in brain and RBCs f...

Quaternary and tertiary aldoxime antidotes for organophosphate exposure in a zebrafish model system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmidt, Hayden R.; Radić, Zoran; Taylor, Palmer

The zebrafish is rapidly becoming an important model system for screening of new therapeutics. Here we evaluated the zebrafish as a potential pharmacological model for screening novel oxime antidotes to organophosphate (OP)-inhibited acetylcholinesterase (AChE). The k{sub i} values determined for chlorpyrifos oxon (CPO) and dichlorvos (DDVP) showed that CPO was a more potent inhibitor of both human and zebrafish AChE, but overall zebrafish AChE was less sensitive to OP inhibition. In contrast, aldoxime antidotes, the quaternary ammonium 2-PAM and tertiary amine RS-194B, showed generally similar overall reactivation kinetics, k{sub r}, in both zebrafish and human AChE. However, differences between themore » K{sub ox} and k{sub 2} constants suggest that zebrafish AChE associates more tightly with oximes, but has a slower maximal reactivation rate than human AChE. Homology modeling suggests that these kinetic differences result from divergences in the amino acids lining the entrance to the active site gorge. Although 2-PAM had the more favorable in vitro reactivation kinetics, RS-194B was more effective antidote in vivo. In intact zebrafish embryos, antidotal treatment with RS-194B rescued embryos from OP toxicity, whereas 2-PAM had no effect. Dechorionation of the embryos prior to antidotal treatment allowed both 2-PAM and RS-194B to rescue zebrafish embryos from OP toxicity. Interestingly, RS-194B and 2-PAM alone increased cholinergic motor activity in dechorionated embryos possibly due to the reversible inhibition kinetics, K{sub i} and αK{sub i}, of the oximes. Together these results demonstrate that the zebrafish at various developmental stages provides an excellent model for investigating membrane penetrant antidotes to OP exposure. - Highlights: • Zebrafish AChE shares significant structural similarities with human AChE. • OP-inhibited zebrafish and human AChE exhibit similar reactivation kinetics. • The zebrafish chorion is permeable to BBB penetrant and not charged aldoximes. • Zebrafish are a good aquatic model for studying centrally acting antidotes.« less

The efficacy of HI-6 DMS in a sustained infusion against percutaneous VX poisoning in the guinea-pig.

PubMed

Whitmore, C; Cook, A R; Mann, T; Price, M E; Emery, E; Roughley, N; Flint, D; Stubbs, S; Armstrong, S J; Rice, H; Tattersall, J E H

2018-09-01

Post-exposure nerve agent treatment usually includes administration of an oxime, which acts to restore function of the enzyme acetylcholinesterase (AChE). For immediate treatment of military personnel, this is usually administered with an autoinjector device, or devices containing the oxime such as pralidoxime, atropine and diazepam. In addition to the autoinjector, it is likely that personnel exposed to nerve agents, particularly by the percutaneous route, will require further treatment at medical facilities. As such, there is a need to understand the relationship between dose rate, plasma concentration, reactivation of AChE activity and efficacy, to provide supporting evidence for oxime infusions in nerve agent poisoning. Here, it has been demonstrated that intravenous infusion of HI-6, in combination with atropine, is efficacious against a percutaneous VX challenge in the conscious male Dunkin-Hartley guinea-pig. Inclusion of HI-6, in addition to atropine in the treatment, improved survival when compared to atropine alone. Additionally, erythrocyte AChE activity following poisoning was found to be dose dependent, with an increased dose rate of HI-6 (0.48mg/kg/min) resulting in increased AChE activity. As far as we are aware, this is the first study to correlate the pharmacokinetic profile of HI-6 with both its pharmacodynamic action of reactivating nerve agent inhibited AChE and with its efficacy against a persistent nerve agent exposure challenge in the same conscious animal. Copyright © 2017 Crown Copyright. Published by Elsevier B.V. All rights reserved.

Oxidative stress in organophosphate poisoning: role of standard antidotal therapy.

PubMed

Vanova, Nela; Pejchal, Jaroslav; Herman, David; Dlabkova, Alzbeta; Jun, Daniel

2018-08-01

Despite the main mechanism of organophosphate (OP) toxicity through inhibition of acetylcholinesterase (AChE) being well known over the years, some chronic adverse health effects indicate the involvement of additional pathways. Oxidative stress is among the most intensively studied. Overstimulation of cholinergic and glutamatergic nervous system is followed by intensified generation of reactive species and oxidative damage in many tissues. In this review, the role of oxidative stress in pathophysiology of OP poisoning and the influence of commonly used medical interventions on its levels are discussed. Current standardized therapy of OP intoxications comprises live-saving administration of the anticholinergic drug atropine accompanied by oxime AChE reactivator and diazepam. The capability of these antidotes to ameliorate OP-induced oxidative stress varies between both therapeutic groups and individual medications within the drug class. Regarding oxidative stress, atropine does not seem to have a significant effect on oxidative stress parameters in OP poisoning. In a case of AChE reactivators, pro-oxidative and antioxidative properties could be found. It is assumed that the ability of oximes to trigger oxidative stress is rather associated with their chemical structure than reactivation efficacy. The data indicating the potency of diazepam in preventing OP-induced oxidative stress are not available. Based on current knowledge on the mechanism of OP-mediated oxidative stress, alternative approaches (including antioxidants or multifunctional drugs) in therapy of OP poisoning are under consideration. Copyright © 2018 John Wiley & Sons, Ltd.

Milbemycins: More than Efflux Inhibitors for Fungal Pathogens

PubMed Central

Silva, Luis Vale; Sanguinetti, Maurizio; Vandeputte, Patrick; Torelli, Riccardo; Rochat, Bertrand

2013-01-01

Existing antifungal agents are still confronted to activities limited to specific fungal species and to the development of resistance. Several improvements are possible either by tackling and overcoming resistance or exacerbating the activity of existing antifungal agents. In Candida glabrata, azole resistance is almost exclusively mediated by ABC transporters (including C. glabrata CDR1 [CgCDR1] and CgCDR2) via gain-of-function mutations in the transcriptional activator CgPDR1 or by mitochondrial dysfunctions. We also observed that azole resistance was correlating with increasing virulence and fitness of C. glabrata in animal models of infection. This observation motivated the re-exploitation of ABC transporter inhibitors as a possible therapeutic intervention to decrease not only the development of azole resistance but also to interfere with the virulence of C. glabrata. Milbemycins are known ABC transporter inhibitors, and here we used commercially available milbemycin A3/A4 oxim derivatives to verify this effect. As expected, the derivatives were inhibiting C. glabrata efflux with the highest activity for A3 oxim below 1 μg/ml. More surprising was that oxim derivatives had intrinsic fungicidal activity above 3.2 μg/ml, thus highlighting effects additional to the efflux inhibition. Similar values were obtained with C. albicans. Our data show that the fungicidal activity could be related to reactive oxygen species formation in these species. Transcriptional analysis performed both in C. glabrata and C. albicans exposed to A3 oxim highlighted a core of commonly regulated genes involved in stress responses, including genes involved in oxidoreductive processes, protein ubiquitination, and vesicle trafficking, as well as mitogen-activated protein kinases. However, the transcript profiles contained also species-specific signatures. Following these observations, experimental treatments of invasive infections were performed in mice treated with the commercial A3/A4 oxim preparation alone or in combination with fluconazole. Tissue burden analysis revealed that oxims on their own were able to decrease fungal burdens in both Candida species. In azole-resistant isolates, oxims acted synergistically in vivo with fluconazole to reduce fungal burden to levels of azole-susceptible isolates. In conclusion, we show here the potential of milbemycins not only as drug efflux inhibitors but also as effective fungal growth inhibitors in C. glabrata and C. albicans. PMID:23208712

Biomonitoring of Organophosphorus Agent Exposure by Reactivation of Cholinesterase Enzyme Based on Carbon Nanotube-Enhanced Flow-Injection Amperometric Detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, Dan; Wang, Jun; Smith, Jordan N.

2009-11-15

A portable, rapid, and sensitive assessment of sub-clinical organophosphorus (OPs) agent exposure based on reactivation of cholinesterase (ChE) from OP-inhibited ChE using rat saliva (in vitro) was developed using an electrochemical sensor coupled with a microflow-injection system. The sensor was based on a carbon nanotube (CNT)-modified screen printed carbon electrode (SPE), which was integrated into a flow cell. Due to the extent of inter-individual ChE activity variability, ChE biomonitoring often requires an initial base-line determination (non-inhibited) of enzyme activity which is then directly compared with activity after OP exposure. This manuscript described an alternative strategy where reactivation of the phosphorylatedmore » enzyme was exploited to enable measurement of both inhibited and baseline ChE activity (i.e. after reactivation) in the same sample. The use of CNT makes the electrochemical detection of the products from enzymatic reactions more feasible with extremely high sensitivity and at low potentials. Paraoxon was selected as a model OP compound for in vitro inhibition studies. Some experiment parameters, (e.g. inhibition and reactivation times), have been optimized such that, 92 - 95% ChE reactivation can be achieved over a broad range of ChE inhibition (5 - 94 %) with paraoxon. The extent of enzyme inhibition using this electrochemical sensor correlates well with conventional enzyme activity measurements.« less

Oxime-Induced Reactivation and Efficacy against Lethality in Phosphinate-Intoxicated Guinea Pigs.

DTIC Science & Technology

1988-03-01

poisoning by pretreatment with a carbamate. Toxicol. Appl. Pharmacol., 43, 207-216. 5. Heyl, W. C., Harris, L. W., and Stitcher , D. L. (1978). Effects of...Lieske, C. N. (1984). Unpublished results. 12. Harris, L. W., Stitcher , D. L., Heyl, W. C., Lieske, C. N., Lowe, J. R., Clark, J. H., and Broomfield, C

Synthesis, X-ray crystallography, spectroscopic (FT-IR, 1H &13C NMR and UV), computational (DFT/B3LYP) and enzymes inhibitory studies of 7-hydroximinocholest-5-en-3-ol acetate

NASA Astrophysics Data System (ADS)

Ahmad, Faheem; Parveen, Mehtab; Alam, Mahboob; Azaz, Shaista; Malla, Ali Mohammed; Alam, Mohammad Jane; Lee, Dong-Ung; Ahmad, Shabbir

2016-07-01

The present study reports the synthesis of 7-Hydroximinocholest-5-en-3-ol acetate (syn. 3β-acetoxycholest-5-en-7-one oxime; in general, steroidal oxime). The identity of steroidal molecule was confirmed by NMR, FT-IR, MS, CHN microanalysis and X-ray crystallography. DFT calculations on the titled molecule have been performed. The molecular structure and spectra interpreted by Gaussian hybrid computational analysis theory (B3LYP) are found to be in good correlation with the experimental data obtained from the various spectrophotometric techniques. The vibrational bands appearing in the FTIR are assigned with great accuracy using harmonic frequencies along with intensities and animated modes. Molecular properties like HOMO-LUMO analysis, chemical reactivity descriptors, MEP mapping, dipole moment and natural atomic charges have been presented at the same level of theory. Moreover, the Hirshfeld analysis was carried out to ascertain the secondary interactions and associated 2D fingerprint plots. The percentages of various interactions are pictorialized by fingerprint plots of Hirshfeld surface. Steroidal oxime exhibited promising inhibitory activity against acetylcholinesterase (AChE) as compared to the reference drug, tacrine. Molecular docking was performed to introduce steroidal molecules into the X-ray crystal structures of acetylcholinesterase at the active site to find out the probable binding mode. The results of molecular docking admitted that steroidal oxime may exhibit enzyme inhibitor activity.

Suitability of cholinesterase of polychaete Diopatra neapolitana as biomarker of exposure to pesticides: In vitro characterization.

PubMed

Mennillo, Elvira; Casu, Valentina; Tardelli, Federica; De Marchi, Lucia; Freitas, Rosa; Pretti, Carlo

2017-01-01

Cholinesterases of Diopatra neapolitana were characterized for their activity in whole body and different body segments (apical, intermediate, posterior), substrate affinity (acetyl-, butyryl-, propionylthiocholine), kinetic parameters (K m and V max ) and in vitro response to model inhibitors (eserine hemisulfate, isoOMPA, BW284C51) and carbamates (carbofuran, methomyl, aldicarb and carbaryl). Results showed that the rate of hydrolysis for acetyl- and propionylthiocholine was higher in the posterior segment than the apical/intermediate segments and whole body. Cholinesterases of D. neapolitana showed a substrate preference for acetylthiocholine followed by propionylthiocholine; butyrylthioline was poorly hydrolyzed indicating, together with the absence of inhibition by the specific inhibitor and the absence of reactive bands in native electrophoresis, a lack of an active butyrylcholinesterase, differently than that observed in other Annelida species. The degree of inhibition by selected carbamates of cholinesterase activity with propionylthiocholine as substrate was higher than that observed with ATChI-ChE activity; aldicarb showed the highest inhibitory effect. Copyright © 2016 Elsevier Inc. All rights reserved.

Acetylcholine content and cholinesterase activity as related to the combined effects of allergen and radiation. [Rats, gamma radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lipshits, R.U.; Kratinova, M.A.

1977-01-01

Rats were given intraperitoneal injections of antigen and exposed to 200 R of gamma radiation. Acetylcholine content and cholinesterase activity of blood were analyzed every 5 days for 30 days. The interval between sensitization and irradiation determined the direction of changes in allergic reactions. The radiation appreciably attenuated active sensitization of rats. The degree of sensitization was related to changes in cholinergic processes. The data confirmed the assumption that cholinergic systems are involved in the mechanisms of change in allergic reactivity under the influence of radiation. (HLW)

FTIR study of the photoreaction of bovine rhodopsin in the presence of hydroxylamine.

PubMed

Katayama, Kota; Furutani, Yuji; Kandori, Hideki

2010-07-15

In bovine rhodopsin, 11-cis-retinal forms a Schiff base linkage with Lys296. The Schiff base is not reactive to hydroxylamine in the dark, which is consistent with the well-protected retinal binding site. In contrast, under illumination it easily forms all-trans retinal oxime, resulting in the loss of color. This suggests that activation of rhodopsin creates a specific reaction channel for hydroxylamine or loosens the chromophore binding pocket. In the present study, to extract structural information on the Schiff base vicinity and to understand the changes upon activation of rhodopsin, we compared light-induced FTIR difference spectra of bovine rhodopsin in the presence and absence of hydroxylamine under physiological pH (approximately 7). Although the previous FTIR study did not observe the complex formation between rhodopsin and G-protein transducin in hydrated films, the present study clearly shows that hydrated films can be used for studies of the interaction between rhodopsin and hydroxylamine. Hydroxylamine does not react with the Schiff base of Meta-I intermediate trapped at 240 K, possibly because of decreased conformational motions under the frozen environment, while FTIR spectroscopy showed that hydroxylamine affects the hydrogen bonds of the Schiff base and water molecules in Meta-I. In contrast, formation of the retinal oxime was clearly observed at 280 K, the characteristic temperature of Meta-II accumulation in the absence of hydroxylamine, and time-dependent formation of retinal oxime was observed from Meta-II at 265 K as well. The obtained difference FTIR spectra of retinal oxime and opsin are different from that of Meta-II. It is likely that the antiparallel beta-sheet constituting a part of the retinal binding pocket at the extracellular surface is structurally disrupted in the presence of hydroxylamine, which allows the hydrolysis of the Schiff base into retinal oxime.

Timing of decontamination and treatment in case of percutaneous VX poisoning: a mini review.

PubMed

Joosen, Marloes J A; van der Schans, Marcel J; Kuijpers, Willem C; van Helden, Herman P M; Noort, Daan

2013-03-25

Low volatile organophosphorous nerve agents such as VX, will most likely enter the body via the skin. The pharmacokinetics of drugs such as oximes, atropine and diazepam, are not aligned with the variable and persistent toxicokinetics of the agent. Repeated administration of these drugs showed to improve treatment efficacy compared to a single injection treatment. Because of the effectiveness of continuous treatment, it was investigated to what extent a subchronic pretreatment with carbamate (pyridostigmine or physostigmine combined with either procyclidine or scopolamine) would protect against percutaneous VX exposure. Inclusion of scopolamine in the pretreatment prevented seizures in all animals, but none of the pretreatments affected survival time or the onset time of cholinergic signs. These results indicate that percutaneous poisoning with VX requires additional conventional treatment in addition to the current pretreatment regimen. Decontamination of VX-exposed skin is one of the most important countermeasures to mitigate the effects of the exposure. To evaluate the window of opportunity for decontamination, the fielded skin decontaminant Reactive Skin Decontaminant Lotion (RSDL) was tested at different times in hairless guinea pigs percutaneously challenged with 4× LD50 VX in IPA. The results showed that RSDL decontamination at 15 min after exposure could not prevent progressive blood cholinesterase inhibition and therefore would still require additional treatment. A similar decontamination regimen with RSDL at 90 min showed that it still might effectively increase the time window of opportunity for treatment. In conclusion, the delay in absorption presents a window of opportunity for decontamination and treatment. The continuous release of VX from the skin presents a significant challenge for efficacious therapy, which should ideally consist of thorough decontamination and continuous treatment. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Role of water in aging of human butyrylcholinesterase inhibited by echothiophate: the crystal structure suggests two alternative mechanisms of aging.

PubMed

Nachon, Florian; Asojo, Oluwatoyin A; Borgstahl, Gloria E O; Masson, Patrick; Lockridge, Oksana

2005-02-01

Organophosphorus poisons (OP) bind covalently to the active-site serine of cholinesterases. The inhibited enzyme can usually be reactivated with powerful nucleophiles such as oximes. However, the covalently bound OP can undergo a suicide reaction (termed aging) yielding nonreactivatable enzyme. In human butyrylcholinesterase (hBChE), aging involves the residues His438 and Glu197 that are proximal to the active-site serine (Ser198). The mechanism of aging is known in detail for the nerve gases soman, sarin, and tabun as well as the pesticide metabolite isomalathion. Aging of soman- and sarin-inhibited acetylcholinesterase occurs by C-O bond cleavage, whereas that of tabun- and isomalathion-inhibited acetylcholinesterase occurs by P-N and P-S bond cleavage, respectively. In this work, the crystal structures of hBChE inhibited by the ophthalmic reagents echothiophate (nonaged and aged) and diisopropylfluorophosphate (aged) were solved and refined to 2.1, 2.25, and 2.2 A resolution, respectively. No appreciable shift in the position of the catalytic triad histidine was observed between the aged and nonaged conjugates of hBChE. This absence of shift contrasts with the aged and nonaged crystal structures of Torpedo californica acetylcholinesterase inhibited by the nerve agent VX. The nonaged hBChE structure shows one water molecule interacting with Glu197 and the catalytic triad histidine (His438). Interestingly, this water molecule is ideally positioned to promote aging by two mechanisms: breaking either a C-O bond or a P-O bond. Pesticides and certain stereoisomers of nerve agents are expected to undergo aging by breaking the P-O bond.

Naturally Occurring Variations in the Human Cholinesterase Genes: Heritability and Association with Cardiovascular and Metabolic Traits

PubMed Central

Valle, Anne M.; Radić, Zoran; Rana, Brinda K.; Mahboubi, Vafa; Wessel, Jennifer; Shih, Pei-an Betty; Rao, Fangwen; O'Connor, Daniel T.

2011-01-01

Cholinergic neurotransmission in the central and autonomic nervous systems regulates immediate variations in and longer-term maintenance of cardiovascular function with acetylcholinesterase (AChE) activity that is critical to temporal responsiveness. Butyrylcholinesterase (BChE), largely confined to the liver and plasma, subserves metabolic functions. AChE and BChE are found in hematopoietic cells and plasma, enabling one to correlate enzyme levels in whole blood with hereditary traits in twins. Using both twin and unrelated subjects, we found certain single nucleotide polymorphisms (SNPs) in the ACHE gene correlated with catalytic properties and general cardiovascular functions. SNP discovery from ACHE resequencing identified 19 SNPs: 7 coding SNPs (cSNPs), of which 4 are nonsynonymous, and 12 SNPs in untranslated regions, of which 3 are in a conserved sequence of an upstream intron. Both AChE and BChE activity traits in blood were heritable: AChE at 48.8 ± 6.1% and BChE at 81.4 ± 2.8%. Allelic and haplotype variations in the ACHE and BCHE genes were associated with changes in blood AChE and BChE activities. AChE activity was associated with BP status and SBP, whereas BChE activity was associated with features of the metabolic syndrome (especially body weight and BMI). Gene products from cDNAs with nonsynonymous cSNPs were expressed and purified. Protein expression of ACHE nonsynonymous variant D134H (SNP6) is impaired: this variant shows compromised stability and altered rates of organophosphate inhibition and oxime-assisted reactivation. A substantial fraction of the D134H instability could be reversed in the D134H/R136Q mutant. Hence, common genetic variations at ACHE and BCHE loci were associated with changes in corresponding enzymatic activities in blood. PMID:21493754

Experimental and theoretical vibrational spectroscopy studies of acetohydroxamic acid and desferrioxamine B in aqueous solution: Effects of pH and iron complexation

NASA Astrophysics Data System (ADS)

Edwards, David C.; Nielsen, Steen B.; Jarzęcki, Andrzej A.; Spiro, Thomas G.; Myneni, Satish C. B.

2005-07-01

The deprotonation and iron complexation of the hydroxamate siderophore, desferrioxamine B (desB), and a model hydroxamate ligand, acetohydroxamic acid (aHa), were studied using infrared, resonance Raman and UV-vis spectroscopy. The experimental spectra were interpreted by a comparison with DFT calculated spectra of aHa (partly hydrated) and desB (reactive groups of unhydrated molecule) at the B3LYP/6-31G* level of theory. The ab initio models include three water molecules surrounding the deprotonation site of aHa to account for partial hydration. Experiments and calculations were also conducted in D 2O to verify spectral assignments. These studies of aHa suggest that the cis-keto-aHa is the dominant form, and its deprotonation occurs at the oxime oxygen atom in aqueous solutions. The stable form of iron-complexed aHa is identified as Fe(aHa) 3 for a wide range of pH conditions. The spectral information of aHa and an ab initio model of desB were used to interpret the chemical state of different functional groups in desB. Vibrational spectra of desB indicate that the oxime and amide carbonyl groups can be identified unambiguously. Vibrational spectral analysis of the oxime carbonyl after deprotonation and iron complexation of desB indicates that the conformational changes between anion and the iron-complexed anion are small. Enhanced electron delocalization in the oxime group of Fe-desB when compared to that of Fe(aHa) 3 may be responsible for higher stability constant of the former.

Pseudocatalytic scavenging of the nerve agent VX with human blood components and the oximes obidoxime and HI-6.

PubMed

Wille, Timo; von der Wellen, Jens; Thiermann, Horst; Worek, Franz

2017-03-01

Despite six decades of extensive research in medical countermeasures against nerve agent poisoning, a broad spectrum acetylcholinesterase (AChE) reactivator is not yet available. One current approach is directed toward synthesizing oximes with high affinity and reactivatability toward butyrylcholinesterase (BChE) in plasma to generate an effective pseudocatalytic scavenger. An interim solution could be the administration of external AChE or BChE from blood products to augment pseudocatalytic scavenging with slower but clinically approved oximes to decrease nerve agent concentrations in the body. We here semiquantitatively investigate the ability of obidoxime and HI-6 to decrease the inhibitory activity of VX with human AChE and BChE from whole blood, erythrocyte membranes, erythrocytes, plasma, clinically available fresh frozen plasma and packed red blood cells. The main findings are that whole blood showed a VX concentration-dependent decrease in inhibitory activity with HI-6 being more potent than obidoxime. Using erythrocytes and erythrocyte membranes again, HI-6 was more potent compared to obidoxime. With freshly prepared plasma, obidoxime and HI-6 showed comparable results for the decrease in VX. The use of the clinically available blood products revealed that packed red blood cells showed similar kinetics as fresh erythrocytes. Fresh frozen plasma resulted in a slower and incomplete decrease in inhibitory plasma compared to freshly prepared plasma. In conclusion, the administration of blood products in combination with available oximes augments pseudocatalytic scavenging and might be useful to decrease the body load of persistent, highly toxic nerve agents.

Recent advances in acetylcholinesterase Inhibitors and Reactivators: an update on the patent literature (2012-2015).

PubMed

McHardy, Stanton F; Wang, Hua-Yu Leo; McCowen, Shelby V; Valdez, Matthew C

2017-04-01

Acetylcholinesterase (AChE) is the major enzyme that hydrolyzes acetylcholine, a key neurotransmitter for synaptic transmission, into acetic acid and choline. Mild inhibition of AChE has been shown to have therapeutic relevance in Alzheimer's disease (AD), myasthenia gravis, and glaucoma among others. In contrast, strong inhibition of AChE can lead to cholinergic poisoning. To combat this, AChE reactivators have to be developed to remove the offending AChE inhibitor, restoring acetylcholine levels to normal. Areas covered: This article covers recent advances in the development of acetylcholinesterase modulators, including both inhibitors of acetylcholinesterase for the efforts in development of new chemical entities for treatment of AD, as well as re-activators for resurrection of organophosphate bound acetylcholinesterase. Expert opinion: Over the past three years, research efforts have continued to identify novel small molecules as AChE inhibitors for both CNS and peripheral diseases. The more recent patent activity has focused on three AChE ligand design areas: derivatives of known AChE ligands, natural product based scaffolds and multifunctional ligands, all of which have produced some unique chemical matter with AChE inhibition activities in the mid picomolar to low micromolar ranges. New AChE inhibitors with polypharmacology or dual inhibitory activity have also emerged as highlighted by new AChE inhibitors with dual activity at L-type calcium channels, GSK-3, BACE1 and H3, although most only show low micromolar activity, thus further research is warranted. New small molecule reactivators of organophosphate-inhibited AChE have also been disclosed, which focused on the design of neutral ligands with improved pharmaceutical properties and blood-brain barrier (BBB) penetration. Gratifyingly, some research in this area is moving away from the traditional quaternary pyridinium oximes AChE reactivators, while still employing the necessary reactivation group (oximes). However, selectivity over inhibition of native AChE enzyme, effectiveness of reactivation, broad-spectrum reactivation against multiple organophosphates and reactivation of aged-enzyme continue to be hurdles for this area of research.

Novel Organophosphate Ligand O-(2-Fluoroethyl)-O-(p-Nitrophenyl)Methylphosphonate: Synthesis, Hydrolytic Stability and Analysis of the Inhibition and Reactivation of Cholinesterases.

PubMed

Chao, Chih-Kai; Ahmed, S Kaleem; Gerdes, John M; Thompson, Charles M

2016-11-21

The organophosphate O-(2-fluoroethyl)-O-(p-nitrophenyl) methyphosphonate 1 is the first-in-class, fluorine-18 radiolabeled organophosphate inhibitor ([ 18 F]1) of acetylcholinesterase (AChE). In rats, [ 18 F]1 localizes in AChE rich regions of the brain and other tissues where it likely exists as the (CH 3 )( 18 FCH 2 CH 2 O)P(O)-AChE adduct (ChE-1). Characterization of this adduct would define the inhibition mechanism and subsequent postinhibitory pathways and reactivation rates. To validate this adduct, the stability (hydrolysis) of 1 and ChE-1 reactivation rates were determined. Base hydrolysis of 1 yields p-nitrophenol and (CH 3 ) (FCH 2 CH 2 O)P(O)OH with pseudo first order rate constants (k obsd ) at pH 7.4 (PBS) of 3.25 × 10 -4 min -1 (t 1/2 = 35.5 h) at 25 °C and 8.70 × 10 -4 min -1 (t 1/2 = 13.3 h) at 37 °C. Compound 1 was a potent inhibitor of human acetylcholinesterase (HuAChE; k i = 7.5 × 10 5 M -1 min -1 ), electric eel acetylcholinesterase (EEAChE) (k i = 3.0 × 10 6 M -1 min -1 ), and human serum butyrylcholinesterase (HuBChE; 1.95 × 10 5 M -1 min -1 ). Spontaneous and oxime-mediated reactivation rates for the (CH 3 ) (FCH 2 CH 2 O)P(O)-serine ChE adducts using 2-PAM (10 μM) were (a) HuAChE 8.8 × 10 -5 min -1 (t 1/2 = 131.2 h) and 2.41 × 10 -2 min -1 (t 1/2 = 0.48 h), (b) EEAChE 9.32 × 10 -3 min -1 (t 1/2 = 1.24 h) and 3.33 × 10 -2 min -1 (t 1/2 = 0.35 h), and (c) HuBChE 1.16 × 10 -4 min -1 (t 1/2 = 99.6 h) and 4.19 × 10 -2 min -1 (t 1/2 = 0.27 h). All ChE-1 adducts undergo rapid and near complete restoration of enzyme activity following addition of 2-PAM (30 min), and no aging was observed for either reactivation process. The fast reactivation rates and absence of aging of ChE-1 adducts are explained on the basis of the electron-withdrawing fluorine group that favors the nucleophilic reactivation processes but disfavors cation-based dealkylation aging mechanisms. Therefore, the likely fate of radiolabeled compound 1 in vivo is the formation of (CH 3 )(FCH 2 CH 2 O)P(O)-serine adducts and monoacid (CH 3 )(FCH 2 CH 2 O)P(O)OH from hydrolysis and reactivation.

Anticonvulsant actions of anticholinergic drugs in soman poisoning. (Reannouncement with new availability information)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Capacio, B.R.; Shih, T.M.

1991-12-31

The acute effects of the organophosphorus cholinesterase inhibitor soman include hypersecretions, convulsions, and death. The purpose of this study was to evaluate the anticholinergic compounds, aprophen, atropine sulfate, azaprophen, benactyzine, benztropine, biperiden, scopolamine HBr, and trihexyphenidyl for their efficacy in preventing soman-induced hypersecretions and convulsions. Male rats were injected with the oxime HI-6 (125 mg/kg, i.p.), to increase survival time, along with various intramuscular doses of the anticholinergics 30 min prior to a dose of soman that produced 100% convulsions. Signs of intoxication as well as the time-to-onset of convulsions were observed. The calculated anticonvulsant median effective dose values weremore » 0.18, 0.33, 0.36, 0.55, 2.17, 2.30, 2.45, and 31.09 micro mol per kilogram for scopolamine HBr, biperiden, trihexyphenidy, benactyzine, benztropine, azaprophen, aprophen, and atropine sulfate, respectively. The same rank order by potency for inhibition of hypersecretions among these compounds was observed.« less

Bridged Bicyclic Oximes as Acetylcholinesterase Reactivators

DTIC Science & Technology

1988-04-03

with acetylcholine as substrate, is based on coupling away the choline produced from the esterase reaction with choline kinase, which catalyzes the...transfer of the y-phosphate from ATP to choline , producing ADP, and then removed with the pyruvate kinase-lactate dehydrogenase couple, and disappearance...nitrobenzoic acid absorbs strongly at 412 nm. Choline kinase and acetylcholinesterase were purchased from Sigma as the lyophilized powders. Each enzyme

DECREASED HEART RATE IS ASSOCIATED WITH CARBAMATE-INDUCED ACTIVATION OF PRO-INFLAMMATORY SERUM PROTEINS.

EPA Science Inventory

Previously we reported that chlorpyrifos (CHP), an irreversible cholinesterase (ChE) inhibitor, induces hypertension in rats. Concomitant with hypertension, we found an increase in C-reactive protein, macrophage inflammatory protein-2 , monocyte chemotactic protein-5 and interfer...

The role of the oximes HI-6 and HS-6 inside human acetylcholinesterase inhibited with nerve agents: a computational study.

PubMed

Cuya, Teobaldo; Gonçalves, Arlan da Silva; da Silva, Jorge Alberto Valle; Ramalho, Teodorico C; Kuca, Kamil; C C França, Tanos

2017-10-27

The oximes 4-carbamoyl-1-[({2-[(E)-(hydroxyimino) methyl] pyridinium-1-yl} methoxy) methyl] pyridinium (known as HI-6) and 3-carbamoyl-1-[({2-[(E)-(hydroxyimino) methyl] pyridinium-1-yl} methoxy) methyl] pyridinium (known as HS-6) are isomers differing from each other only by the position of the carbamoyl group on the pyridine ring. However, this slight difference was verified to be responsible for big differences in the percentual of reactivation of acetylcholinesterase (AChE) inhibited by the nerve agents tabun, sarin, cyclosarin, and VX. In order to try to find out the reason for this, a computational study involving molecular docking, molecular dynamics, and binding energies calculations, was performed on the binding modes of HI-6 and HS-6 on human AChE (HssAChE) inhibited by those nerve agents.

Intravenous application of HI-6 salts (dichloride and dimethansulphonate) in pigs: comparison with pharmacokinetics profile after intramuscular administration.

PubMed

Zdarova Karasova, Jana; Zemek, Filip; Kunes, Martin; Kvetina, Jaroslav; Chladek, Jaroslav; Jun, Daniel; Bures, Jan; Tachecí, Ilja; Kuca, Kamil

2013-01-01

Oxime HI-6 is an acetylcholinesterase reactivator therapeutically efficient against nerve agents. Because of their physico-chemical properties, oximes are typically applied intramuscularly (i.m.). This route of administration has also some disadvantages, and alternative strategies ought to be examined. We evaluated the pharmacokinetic profiles of two HI-6 salts after their intravenous (i.v.) administration, and compare the results with the known pharmacokinetics after i.m. administration. Pigs were administered with HI-6 salts (i.v), either HI-6 dichloride (10.71 mg/kg) or molar equivalent HI-6 dimethansulphonate (13.59 mg/kg). Doses of the HI-6 salts corresponded with a standard HI-6 dichloride dose in one autoinjector (500 mg) and were recalculated for one kilogram of body weight. The main pharmacokinetic parameters are comparable after i.v. and i.m. HI-6 administration. The compared pharmacokinetic parameters were half-life, terminal rate constant, mean residence time of the molecule in the body, clearance, and the apparent volume in the terminal phase. The bioavailability after i.m. administration was comparable with that of i.v.; these results suggest that the oxime is well released from the muscle depot. Significant differences were found in parameters Cmax and Tmax which are important in cases of emergency when rapidity and bioavailability are paramount for the success of treatment. I.v. administration should solve the problem of rapid clearance. Infusion or bolus administration may be considered as a logical subsequent step in oxime treatment strategy. The main advantage is in maintenance of an effective therapeutic plasma concentration, a more easily achievable effective therapeutic concentration, and fewer local adverse reactions.

Management of acute organophosphorus pesticide poisoning.

PubMed

Eddleston, Michael; Buckley, Nick A; Eyer, Peter; Dawson, Andrew H

2008-02-16

Organophosphorus pesticide self-poisoning is an important clinical problem in rural regions of the developing world, and kills an estimated 200,000 people every year. Unintentional poisoning kills far fewer people but is a problem in places where highly toxic organophosphorus pesticides are available. Medical management is difficult, with case fatality generally more than 15%. We describe the limited evidence that can guide therapy and the factors that should be considered when designing further clinical studies. 50 years after first use, we still do not know how the core treatments--atropine, oximes, and diazepam--should best be given. Important constraints in the collection of useful data have included the late recognition of great variability in activity and action of the individual pesticides, and the care needed cholinesterase assays for results to be comparable between studies. However, consensus suggests that early resuscitation with atropine, oxygen, respiratory support, and fluids is needed to improve oxygen delivery to tissues. The role of oximes is not completely clear; they might benefit only patients poisoned by specific pesticides or patients with moderate poisoning. Small studies suggest benefit from new treatments such as magnesium sulphate, but much larger trials are needed. Gastric lavage could have a role but should only be undertaken once the patient is stable. Randomised controlled trials are underway in rural Asia to assess the effectiveness of these therapies. However, some organophosphorus pesticides might prove very difficult to treat with current therapies, such that bans on particular pesticides could be the only method to substantially reduce the case fatality after poisoning. Improved medical management of organophosphorus poisoning should result in a reduction in worldwide deaths from suicide.

Management of acute organophosphorus pesticide poisoning

PubMed Central

Eddleston, Michael; Buckley, Nick A; Eyer, Peter; Dawson, Andrew H

2008-01-01

Summary Organophosphorus pesticide self-poisoning is an important clinical problem in rural regions of the developing world, and kills an estimated 200 000 people every year. Unintentional poisoning kills far fewer people but is a problem in places where highly toxic organophosphorus pesticides are available. Medical management is difficult, with case fatality generally more than 15%. We describe the limited evidence that can guide therapy and the factors that should be considered when designing further clinical studies. 50 years after first use, we still do not know how the core treatments—atropine, oximes, and diazepam—should best be given. Important constraints in the collection of useful data have included the late recognition of great variability in activity and action of the individual pesticides, and the care needed cholinesterase assays for results to be comparable between studies. However, consensus suggests that early resuscitation with atropine, oxygen, respiratory support, and fluids is needed to improve oxygen delivery to tissues. The role of oximes is not completely clear; they might benefit only patients poisoned by specific pesticides or patients with moderate poisoning. Small studies suggest benefit from new treatments such as magnesium sulphate, but much larger trials are needed. Gastric lavage could have a role but should only be undertaken once the patient is stable. Randomised controlled trials are underway in rural Asia to assess the effectiveness of these therapies. However, some organophosphorus pesticides might prove very difficult to treat with current therapies, such that bans on particular pesticides could be the only method to substantially reduce the case fatality after poisoning. Improved medical management of organophosphorus poisoning should result in a reduction in worldwide deaths from suicide. PMID:17706760

Pralidoxime inhibits paraoxon-induced depression of rocuronium-neuromuscular block in a time-dependent fashion.

PubMed

Narimatsu, Eichi; Niiya, Tomohisa; Takahashi, Kazunobu; Yamauchi, Masanori; Yamakage, Michiaki

2012-07-01

The composite effects of organophosphorus (OP)-cholinesterase (ChE) inhibitors and oximes on the actions of nondepolarizing neuromuscular blockers in acute OP-ChE inhibitor intoxication have not been evaluated in detail. We investigated the effects of paraoxon (Pox) (an OP-ChE inhibitor) and pralidoxime (PAM) (an oxime) on the nondepolarizing neuromuscular blocking action of rocuronium. Isometric twitch tensions of rat left phrenic nerve-hemidiaphragm preparations elicited by indirect (phrenic nerve) supramaximal stimulation at 0.1 Hz were evaluated. Analysis of variance with post hoc testing was used for statistical comparison, and P < .05 was accepted as significant. Rocuronium reduced the indirectly elicited twitch tensions in normal (50% inhibitory concentration [IC(50)], 9.84 [9.64-10.04] μM, mean [95% confidence interval]) and all pretreated diaphragms (P < .01, n = 6) in a concentration-dependent fashion. Paraoxon caused a rightward shift in the rocuronium concentration-twitch tension curve (IC(50), 15.48 [15.24-15.72] μM). The rightward shift was completely inhibited by previous copretreatment (IC(50), 9.98 [9.77-10.20] μM) and partially inhibited by simultaneous copretreatment (IC(50), 11.68 [11.45-11.91] μM) with PAM but was not inhibited by subsequent copretreatment (IC(50), 13.69 [13.39-13.99] μM) with PAM (P < .01, n = 6). Atropine did not influence the rightward shift (P < .01, n = 6). Paraoxon depressed rocuronium-induced neuromuscular block by inhibiting ChEs, and the action of Pox was inhibited by PAM. Pralidoxime acts more intensely when applied earlier. The time-dependent effect of PAM indicates that the preceding presence of PAM in proximity to ChEs before Pox is necessary for definite suppression of the Pox-induced ChE inhibition. Copyright © 2012 Elsevier Inc. All rights reserved.

Identification and Characterization of Novel Catalytic Bioscavengers of Organophosphorus Nerve Agents

DTIC Science & Technology

2013-01-01

hydrolase activity . These strains are Ammoniphilus oxalaticus, Haloarcula sp., and Micromonospora aurantiaca. Lysates from A. oxalaticus had...warfare agents [1–3]. OP nerve agents readily bind covalently to the active site serine in acetylcho- linesterase (AChE), thereby inhibiting the ability...muscarinic receptors, whereas 2-pralidoxime chloride, an oxime nucleophile, reactivates AChE by displacing the phospho- nyl group left on the active site

Butyrylcholinesterase for protection from organophosphorus poisons; catalytic complexities and hysteretic behavior

PubMed Central

Masson, Patrick; Lockridge, Oksana

2009-01-01

Butyrylcholinesterase is a promiscuous enzyme that displays complex kinetic behavior. It is toxicologically important because it detoxifies organophosphorus poisons (OP) by making a covalent bond with the OP. The OP and the butyrylcholinesterase are both inactivated in the process. Inactivation of butyrylcholinesterase has no adverse effects. However inactivation of acetylcholinesterase in nerve synapses can be lethal. OP-inhibited butyrylcholinesterase and acetylcholinesterase can be reactivated with oximes provided the OP has not aged. Strategies for preventing the toxicity of OP include a) treatment with an OP scavenger, b) reaction of nonaged enzyme with oximes, c) reactivation of aged enzyme, d) slowing down aging with peripheral site ligands, and e) design of mutants that rapidly hydrolyze OP. Option (a) has progressed through phase I clinical trials with human butyrylcholinesterase. Option (b) is in routine clinical use. The others are at the basic research level. Butyrylcholinesterase displays complex kinetic behavior including activation by positively charged esters, ability to hydrolyze amides, and a lag time (hysteresis) preceding hydrolysis of benzoylcholine and N-methyl indoxyl acetate. Mass spectrometry has identified new OP binding motifs on tyrosine and lysine in proteins that have no active site serine. It is proposed, but not yet proven, that low dose exposure involves OP modification of proteins that have no active site serine. PMID:20004171

An improved radiosynthesis of O-(2-[18 F]fluoroethyl)-O-(p-nitrophenyl)methylphosphonate: A first-in-class cholinesterase PET tracer.

PubMed

Neumann, Kiel D; Thompson, Charles M; Blecha, Joseph E; Gerdes, John M; VanBrocklin, Henry F

2017-06-15

O-(2-Fluoroethyl)-O-(p-nitrophenyl) methylphosphonate 1 is an organophosphate cholinesterase inhibitor that creates a phosphonyl-serine covalent adduct at the enzyme active site blocking cholinesterase activity in vivo. The corresponding radiolabeled O-(2-[ 18 F]fluoroethyl)-O-(p-nitrophenyl) methylphosphonate, [ 18 F]1, has been previously prepared and found to be an excellent positron emission tomography imaging tracer for assessment of cholinesterases in live brain, peripheral tissues, and blood. However, the previously reported [ 18 F]1 tracer synthesis was slow even with microwave acceleration, required high-performance liquid chromatography separation of the tracer from impurities, and gave less optimal radiochemical yields. In this paper, we report a new synthetic approach to circumvent these shortcomings that is reliant on the facile reactivity of bis-(O,O-p-nitrophenyl) methylphosphonate, 2, with 2-fluoroethanol in the presence of DBU. The cold synthesis was successfully translated to provide a more robust radiosynthesis. Using this new strategy, the desired tracer, [ 18 F]1, was obtained in a non-decay-corrected radiochemical yield of 8 ± 2% (n = 7) in >99% radiochemical and >95% chemical purity with a specific activity of 3174 ± 345 Ci/mmol (EOS). This new facile radiosynthesis routinely affords highly pure quantities of [ 18 F]1, which will further enable tracer development of OP cholinesterase inhibitors and their evaluation in vivo. Copyright © 2017 John Wiley & Sons, Ltd.

Synthesis of two and antibacterial activity of one novel oxime ether derivatives of erythromycin A.

PubMed

Dondas, H A; Yaktubay, N

2003-10-01

The synthesis of novel erythromycin A 9-O-(2-ethenesulfony-ethyl)-oxime and erythromycin A 9-O-(3-oxo-butyl)-oxime from erythromycin A (EA) by the Michael reaction is described and to describe the effects of transformation of ketone in position 9 of EA to an oxime ether. This transformation occurred in a single step without protecting of any functional moiety of erythromycin oxime and zero waste manner in good yield. The antibacterial screen of EA 9-O-(2-ethenesulfony-ethyl)-oxime is also reported.

Nitrite Formation from Hydroxylamine and Oximes by Pseudomonas aeruginosa

PubMed Central

Amarger, Noelle; Alexander, M.

1968-01-01

Nitrite was formed from hydroxylamine and several oximes by intact cells and extracts of Pseudomonas aeruginosa. The activity was induced by the presence of oximes in the culture medium. Nitroalkanes were not intermediates in the conversion of acetaldoxime, acetone oxime, or butanone oxime to nitrite, since nitromethane inhibited the formation of nitrite from the nitro compounds but not from the corresponding oximes. The oxime apparently functions as a constant source of hydroxylamine during growth of the bacterium. Hydroxylamine at low concentration was converted stoichiometrically to nitrite by extracts of the bacterium; high concentrations were inhibitory. Nicotinamide adenine dinucleotide phosphate, oxygen, and other unidentified cofactors were necessary for the reaction. Actively nitrifying extracts possessed no hydroxylamine-cytochrome c reductase activity. Hyponitrite, nitrous oxide, and nitric oxide were not metabolized. PMID:4384968

[Isomeric derivatives of lupinine and epilupinine--organophosphorus inhibitors of cholinesterases].

PubMed

Basova, N E; Kormilitsyn, B N; Perchenok, A Iu; Rosengart, E V; Saakov, V S; Suvorov, A A

2012-01-01

The isomeric-structure analysis data of anticholinesterase action of organophosphorous inhibitors with similar structure help in the search of specific effectors and detection of differences in reactivity of various animals' enzymes. This study compared the data of efficacy in respect of 4 mammal and 5 arthropoda cholinesterase preparations for 26 quinolizidine inhibitors, which molecules contain both the isomeric unbranched and branched alkoxyl radicals in the phosphoryl group, and the epimeric lupinine and epilupinine derivatives in the leaving group. The changes in the alkoxyl radical structure of inhibitor molecules act on their efficacy only with respect to the mammal enzymes ("group" inhibitor specificity). The differences between lupinine and epilupinine derivatives were revealed. Highly specific inhibitors of different enzymes were detected among the tested compounds.

Divergent effects of postmortem ambient temperature on organophosphorus- and carbamate-inhibited brain cholinesterase activity in birds

USGS Publications Warehouse

Hill, E.F.

1989-01-01

Time- and temperature-dependent postmortem changes in inhibited brain cholinesterase (ChE) activity may confound diagnosis of field poisoning of wildlife by anticholinesterase pesticide. Carbamate-inhibited ChE activity may return to normal within 1 to 2 days of exposure of intact carcass to moderate ambient temperature (18-32C). Organophosphorus-inhibited ChE activity becomes more depressed over the same time. Uninhibited ChE activity was resilient to above freezing temperature to 32C for 1 day and 25C for 3 days. Carbamate- and organophosphorus-inhibited ChE can be separated by incubation of homogenate for 1 hour at physiological temperatures; carbamylated ChE can be readily reactivated while phosphorylated ChE cannot.

Efficacy of fresh packed red blood transfusion in organophosphate poisoning.

PubMed

Bao, Hang-Xing; Tong, Pei-Jian; Li, Cai-Xia; Du, Jing; Chen, Bing-Yu; Huang, Zhi-Hui; Wang, Ying

2017-03-01

The mortality rate caused by organophosphate (OP) poisoning is still high, even the standard treatment such as atropine and oxime improves a lot. To search for alternative therapies, this study was aimed to investigate the effects of packed red blood cell (RBC) transfusion in acute OP poisoning, and compare the therapeutic effects of RBCs at different storage times.Patients diagnosed with OP poisoning were included in this prospective study. Fresh RBCs (packed RBCs stored less than 10 days) and longer-storage RBCs (stored more than 10 days but less than 35 days) were randomly transfused or not into OP poisoning patients. Cholinesterase (ChE) levels in blood, atropine usage and durations, pralidoxime durations were measured.We found that both fresh and longer-storage RBCs (200-400 mL) significantly increased blood ChE levels 6 hours after transfusion, shortened the duration for ChE recovery and length of hospital stay, and reduced the usage of atropine and pralidoxime. In addition, fresh RBCs demonstrated stronger therapeutic effects than longer-storage RBCs.Packed RBCs might be an alternative approach in patients with OP poisoning, especially during early stages.

Synthesis, spectra and X-ray crystallography of dipyridin-2-ylmethanone oxime and its CuX2(oxime)2 complexes: Thermal, Hirshfeld surface and DFT analysis

NASA Astrophysics Data System (ADS)

Warad, Ismail; Abdoh, Muneer; Al Ali, Anas; Shivalingegowda, Naveen; Kumara, Karthik; Zarrouk, Abdelkader; Lokanath, Neartur Krishnappagowda

2018-02-01

Dipyridin-2-ylmethanone oxime (C11H9N3O), was prepared using di-2-pyridyl ketone. The oxime ligand and its neutral CuX2 (oxime)2 (X = Cl or Br) complexes have been identified with the aid of several spectroscopic techniques such as: IR, EI-MS, EA, UV-visible, TG, 1H-NMR and finally the structure of the free oxime ligand was confirmed by X-ray diffraction studies. The oxime crystallizes in the monoclinic space group P21/c, with cell parameters a = 8.8811 (8) Å, b = 10.6362 (8) Å, c = 11.2050 (8) Å, β = 109.085 (4) º, V = 1000.26 (14) Å3 and Z = 4. The molecular conformation is stabilized by a strong intramolecular Osbnd H⋯N hydrogen bonding between the hydroxyl group of the oxime moiety and the nitrogen of the pyridine ring. Since the oxime structure was solved by XRD, the ligand structure parameters like bond length and angles were compared to the DFT computed one, the UV-visible to TD-SCF and Hirshfeld surface to MEP analysis.

The kinetic study of the inhibition of human cholinesterases by demeton-S-methyl shows that cholinesterase-based titration methods are not suitable for this organophosphate.

PubMed

Bazire, Alexandre; Gillon, Emilie; Lockridge, Oksana; Vallet, Virginie; Nachon, Florian

2011-04-01

The organophosphorus insecticide, demeton-S-methyl (DSM), is considered as a good surrogate of the highly toxic nerve agent VX for skin absorption studies due to similar physico-chemical properties and in vitro percutaneous penetration profile. But, when skin distribution was estimated by measuring inhibition of cholinesterase activity, the results were poorly reproducible. The various grades of commercial DSM solutions were suspected to be the origin of the discrepancies. This hypothesis was tested by measuring inhibition of human acetyl- and butyrylcholinesterase by two commercial DSM solutions. The inhibition rate was independent on the enzyme concentration confirming pseudo-first order conditions. But complete inhibition of butyrylcholinesterase activity was achieved only when the DSM concentration was at least 1500-fold higher than the enzyme concentration. Besides, complete inhibition of acetylcholinesterase was never achieved. Mass spectrometry analysis of the inhibited butyrylcholinesterase adducts identified monomethoxyphosphorylated-serine, the aged product of inhibition by DSM or a derivative with a modified leaving group. Neither spontaneous reactivation nor aging of the dimethoxyphosphorylated-serine could account for the inhibition kinetics observed, suggesting an overly complicated kinetic scheme not compatible with the requirement of a titration experiment. In conclusion, cholinesterase-based analytical methods should be avoided for DSM titration in skin penetration studies. Copyright © 2011 Elsevier Ltd. All rights reserved.

40 CFR 721.10262 - Oxime, Me vinyl silane (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Oxime, Me vinyl silane (generic). 721... Substances § 721.10262 Oxime, Me vinyl silane (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as oxime, Me vinyl silane (PMN P...

40 CFR 721.10262 - Oxime, Me vinyl silane (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Oxime, Me vinyl silane (generic). 721... Substances § 721.10262 Oxime, Me vinyl silane (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as oxime, Me vinyl silane (PMN P...

40 CFR 721.10261 - Oxime, di-Me silane (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Oxime, di-Me silane (generic). 721... Substances § 721.10261 Oxime, di-Me silane (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as oxime, di-Me silane (PMN P-09-589...

40 CFR 721.10261 - Oxime, di-Me silane (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Oxime, di-Me silane (generic). 721... Substances § 721.10261 Oxime, di-Me silane (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as oxime, di-Me silane (PMN P-09-589...

21 CFR 520.1446 - Milbemcyin oxime and lufenuron tablets.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Milbemcyin oxime and lufenuron tablets. 520.1446... oxime and lufenuron tablets. (a) Specifications—(1) Tablets containing: 2.3 milligrams (mg) milbemycin... 230 mg lufenuron, or 23 mg milbemycin oxime and 460 mg lufenuron. (2) Flavored tablets containing: 2.3...

A comparison of the neuroprotective efficacy of individual oxime (HI-6) and combinations of oximes (HI-6+trimedoxime, HI-6+K203) in soman-poisoned rats.

PubMed

Kassa, Jiri; Karasova, Jana Zdarova; Tesarova, Sandra

2011-07-01

The ability of two combinations of oximes (HI-6+trimedoxime, HI-6+K203) to reduce soman-induced acute neurotoxic signs and symptoms was compared with the neuroprotective efficacy of the oxime HI-6 alone, using a functional observational battery. Soman-induced neurotoxicity and the neuroprotective effects of HI-6 alone and HI-6 combined with trimedoxime or K203 in rats poisoned with soman at a sublethal dose (90 μg/kg intramuscularly, i.m.; 80% of LD₅₀ value) were monitored by the functional observational battery at 24 hours following soman administration. The results indicate that both tested oxime mixtures combined with atropine were able to allow soman-poisoned rats to survive 24 hours following soman challenge, while 4 nontreated soman-poisoned rats and 1 soman-poisoned rat treated with oxime HI-6 alone combined with atropine died within 24 hours following soman poisoning. While the oxime HI-6 alone combined with atropine treatment was able to eliminate a few soman-induced neurotoxic signs and symptoms, both oxime mixtures showed higher neuroprotective efficacy in soman-poisoned rats. Especially, the combination of HI-6 with trimedoxime was able to eliminate most soman-induced neurotoxic signs and symptoms and markedly reduce acute neurotoxicity of soman in rats. Thus, both tested mixtures of oximes combined with atropine were able to increase the neuroprotective effectiveness of antidotal treatment of acute soman poisonings, compared to the individual oxime.

Comparison of Human and Guinea Pig Acetylcholinesterase Sequences and Rates of Oxime-Assisted Reactivation

DTIC Science & Technology

2010-01-01

of appropriate animal model systems. For OP poisoning, the guinea pig (Cavia porcellus) is a commonly used animal model because guinea pigs more...endogenous bioscavenger in vivo. Although guinea pigs historically have been used to test OP poisoning therapies, it has been found recently that guinea pig AChE...transcribed mRNA encoding guinea pig AChE, amplified the resulting cDNA, and sequenced this product. The nucleotide and deduced amino acid sequences of

21 CFR 520.1445 - Milbemycin oxime tablets.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Milbemycin oxime tablets. 520.1445 Section 520... tablets. (a) Specifications—(1) Dogs. Each tablet contains 2.3, 5.75, 11.5, or 23.0 milligrams of milbemycin oxime. (2) Cats. Each tablet contains 5.75, 11.5, or 23.0 milligrams of milbemycin oxime. (b...

Acute soman poisoning in primates neither pretreated nor receiving immediate therapy: value of gacyclidine (GK-11) in delayed medical support.

PubMed

Lallement, G; Clarençon, D; Galonnier, M; Baubichon, D; Burckhart, M F; Peoc'h, M

1999-03-01

Organophosphorus (OP) nerve agents are still used as warfare and terrorism compounds. Classical delayed treatment of victims of organophosphate poisoning includes combined i.v. administration of a cholinesterase reactivator (an oxime), a muscarinic cholinergic receptor antagonist (atropine) and a benzodiazepine anticonvulsant (diazepam). The objective of this study was to evaluate, in a realistic setting, the therapeutic benefit of administration of GK-11 (gacyclidine), an antiglutamatergic compound, as a complement to the above therapy against organophosphate poisoning. Gacyclidine was injected (i.v.) in combination with atropine/diazepam/pralidoxime at man-equivalent doses after a 45- or 30-min latency period to intoxicated primates (2 LD50). The effects of gacyclidine on the animals' survival, electroencephalographic (EEG) activity, signs of toxicity, recovery after challenge and central nervous system histology were examined. The present data demonstrated that atropine/diazepam/pralidoxime alone or combined with gacyclidine did not prevent signs of soman toxicity when treatment was delayed 45 min after poisoning. Atropine/diazepam/pralidoxime also did not control seizures or prevent neuropathology in primates exhibiting severe signs of poisoning when treatment was commenced 30 min after intoxication. However, in this latter case, EEG recordings revealed that additional treatment with gacyclidine was able to stop soman-induced seizures and restore normal EEG activity. This drug also totally prevented the neuropathology observed 5 weeks after soman exposure in animals treated with atropine/diazepam/pralidoxime alone. Overall, in the case of severe OP-poisoning, gacyclidine represents a promising adjuvant therapy to the currently available polymedication to ensure optimal management of organophosphate poisoning in man. This drug is presently being evaluated in a human clinical trial for a different neuroprotective indication. However, it should always be kept in mind that, in the case of severe OP-poisoning, medical intervention must be conducted as early as possible.

Recovery of brain and plasma cholinesterase activities in ducklings exposed to organophosphorus pesticides

USGS Publications Warehouse

Fleming, W.J.

1981-01-01

Brain and plasma cholinesterase (ChE) activities were determined for mallard ducklings (Anas platyrhynchos) exposed to dicrotophos and fenthion. Recovery rates of brain ChE did not differ between ducklings administered a single oral dose vs. a 2-week dietary dose of these organophosphates. Exposure to the organophosphates, followed by recovery of brain ChE, did not significantly affect the degree of brain ChE inhibition or the recovery of ChE activity at a subsequent exposure. Recovery of brain ChE activity followed the general model Y = a + b(logX) with rapid recovery to about 50% of normal, followed by a slower rate of recovery until normal ChE activity levels were attained. Fenthion and dicrotophos-inhibited brain ChE were only slightly reactivated in vitro by pyridine-2-aldoxime methiodide, which suggested that spontaneous reactivation was not a primary method of recovery of ChE activity. Recovery of brain ChE activity can be modeled for interpretation of sublethal inhibition of brain ChE activities in wild birds following environmental applications of organophosphates. Plasma ChE activity is inferior to brain ChE activity for environmental monitoring, because of its rapid recovery and large degree of variation among individuals.

Indirubin-3'-oxime impairs mitochondrial oxidative phosphorylation and prevents mitochondrial permeability transition induction.

PubMed

Varela, Ana T; Gomes, Ana P; Simões, Anabela M; Teodoro, João S; Duarte, Filipe V; Rolo, Anabela P; Palmeira, Carlos M

2008-12-01

Indirubin, a red colored 3,2'-bisindole isomer, is a component of Indigo naturalis and is an active ingredient used in traditional Chinese medicine for the treatment of chronic diseases. The family of indirubin derivatives, such as indirubin-3'-oxime, has been suggested for various therapeutic indications. However, potential toxic interactions such as indirubin effects on mitochondrial bioenergetics are still unknown. This study evaluated the action of indirubin-3'-oxime on the function of isolated rat liver mitochondria contributing to a better understanding of the biochemical mechanisms underlying the multiple effects of indirubin. Indirubin-3'-oxime incubated with isolated rat liver mitochondria, at concentrations above 10microM, significantly depresses the phosphorylation efficiency of mitochondria as inferred from the decrease in the respiratory control and ADP/O ratios, the perturbations in mitochondrial membrane potential and in the phosphorylative cycle induced by ADP. Furthermore, indirubin-3'-oxime at up to 25microM stimulates the rate of state 4 respiration and inhibits state 3 respiration. The increased lag phase of repolarization was associated with a direct inhibition of the mitochondrial ATPase. Indirubin-3'-oxime significantly inhibited the activity of complex II and IV thus explaining the decreased FCCP-stimulated mitochondrial respiration. Mitochondria pre-incubated with indirubin-3'-oxime exhibits decreased susceptibility to calcium-induced mitochondrial permeability transition. This work shows for the first time multiple effects of indirubin-3'-oxime on mitochondrial bioenergetics thus indicating a potential mechanism for indirubin-3'-oxime effects on cell function.

Indirubin-3'-oxime impairs mitochondrial oxidative phosphorylation and prevents mitochondrial permeability transition induction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varela, Ana T.; Gomes, Ana P.; Simoes, Anabela M.

2008-12-01

Indirubin, a red colored 3,2'-bisindole isomer, is a component of Indigo naturalis and is an active ingredient used in traditional Chinese medicine for the treatment of chronic diseases. The family of indirubin derivatives, such as indirubin-3'-oxime, has been suggested for various therapeutic indications. However, potential toxic interactions such as indirubin effects on mitochondrial bioenergetics are still unknown. This study evaluated the action of indirubin-3'-oxime on the function of isolated rat liver mitochondria contributing to a better understanding of the biochemical mechanisms underlying the multiple effects of indirubin. Indirubin-3'-oxime incubated with isolated rat liver mitochondria, at concentrations above 10{mu}M, significantly depressesmore » the phosphorylation efficiency of mitochondria as inferred from the decrease in the respiratory control and ADP/O ratios, the perturbations in mitochondrial membrane potential and in the phosphorylative cycle induced by ADP. Furthermore, indirubin-3'-oxime at up to 25{mu}M stimulates the rate of state 4 respiration and inhibits state 3 respiration. The increased lag phase of repolarization was associated with a direct inhibition of the mitochondrial ATPase. Indirubin-3'-oxime significantly inhibited the activity of complex II and IV thus explaining the decreased FCCP-stimulated mitochondrial respiration. Mitochondria pre-incubated with indirubin-3'-oxime exhibits decreased susceptibility to calcium-induced mitochondrial permeability transition. This work shows for the first time multiple effects of indirubin-3'-oxime on mitochondrial bioenergetics thus indicating a potential mechanism for indirubin-3'-oxime effects on cell function.« less

Cholinesterases as markers of the inflammatory process associated oxidative stress in cattle infected by Babesia bigemina.

PubMed

Doyle, Rovaina L; Da Silva, Aleksandro S; Oliveira, Camila B; França, Raqueli T; Carvalho, Fabiano B; Abdalla, Fátima H; Costa, Pauline; Klafke, Guilherme M; Martins, João R; Tonin, Alexandre A; Castro, Verônica S P; Santos, Franklin G B; Lopes, Sonia T A; Andrade, Cinthia M

2016-06-01

The objective of this study was to assess the influence of an asymptomatic experimental infection by Babesia bigemina on cholinesterase's as markers of the inflammatory process and biomarkers of oxidative imbalance. For this purpose, eight naive animals were used, as follows: four as controls or uninfected; and four infected with an attenuated strain of B. bigemina. Blood samples were collected on days 0, 7 and 11 post-inoculation (PI). Parasitemia was determined by blood smear evaluation, showing that the infection by B. bigemina resulted in mean 0.725 and 0.025% on day 7 and 11 PI, respectively, as well as mild anemia. The activities of acetylcholinesterase, butyrylcholinesterase and catalase were lower, while levels of thiobarbituric acid reactive substances and superoxide dismutase activity were higher in infected animals, when compared with the control group. This attenuated strain of B. bigemina induced an oxidative stress condition, as well as it reduces the cholinesterasés activity in infected and asymptomatic cattle. Therefore, this decrease of cholinesterase in infection by B. bigemina purpose is to inhibit inflammation, for thereby increasing acetylcholine levels, potent anti-inflammatory molecules. Copyright © 2016. Published by Elsevier Ltd.

40 CFR 721.6660 - Polymer of alkanepolyol and poly-alkyl-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime...

Code of Federal Regulations, 2014 CFR

2014-07-01

...-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime-blocked (generic name). 721.6660 Section 721.6660... Polymer of alkanepolyol and poly-alkyl-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime-blocked..., acetone oxime-blocked (PMN P-88-1658) is subject to reporting under this section for the significant new...

40 CFR 721.6660 - Polymer of alkanepolyol and poly-alkyl-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime...

Code of Federal Regulations, 2013 CFR

2013-07-01

...-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime-blocked (generic name). 721.6660 Section 721.6660... Polymer of alkanepolyol and poly-alkyl-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime-blocked..., acetone oxime-blocked (PMN P-88-1658) is subject to reporting under this section for the significant new...

40 CFR 721.6660 - Polymer of alkanepolyol and poly-alkyl-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime...

Code of Federal Regulations, 2012 CFR

2012-07-01

...-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime-blocked (generic name). 721.6660 Section 721.6660... Polymer of alkanepolyol and poly-alkyl-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime-blocked..., acetone oxime-blocked (PMN P-88-1658) is subject to reporting under this section for the significant new...

Novel oxime based flavanone, naringin-oxime: synthesis, characterization and screening for antioxidant activity.

PubMed

Ozyürek, Mustafa; Akpınar, Damla; Bener, Mustafa; Türkkan, Baki; Güçlü, Kubilay; Apak, Reşat

2014-04-05

Recent interest in polyphenolic antioxidants due to their involvement in health benefits has led to the investigation of new polyphenolic compounds with enhanced antioxidant activity. Naringin (4',5,7-trihydroxyflavanone-7-β-l-rhamnoglucoside-(1,2)-α-d-glucopyranoside) is one of the major flavanones in citrus and grapefruit. The present study aimed to synthesize naringin oxime from naringin and to evaluate its antioxidant and anticancer potential using in vitro assay system. The structure of the synthesized compound, naringin oxime, was elucidated by FT-IR, (1)H NMR, elemental analysis and UV-vis spectroscopy. Antioxidant capacity of naringin oxime, as measured by the cupric reducing antioxidant capacity (CUPRAC) method, was found to be higher than that of the parent compound naringin. Other parameters of antioxidant activity (scavenging effects on OH, O2(-), and H2O2) of naringin and naringin oxime were also determined. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Determination of glycoside hydrolase specificities during hydrolysis of plant cell walls using glycome profiling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walker, Johnnie A.; Pattathil, Sivakumar; Bergeman, Lai F.

Glycoside hydrolases (GHs) are enzymes that hydrolyze polysaccharides into simple sugars. To better understand the specificity of enzyme hydrolysis within the complex matrix of polysaccharides found in the plant cell wall, we studied the reactions of individual enzymes using glycome profiling, where a comprehensive collection of cell wall glycan-directed monoclonal antibodies are used to detect polysaccharide epitopes remaining in the walls after enzyme treatment and quantitative nanostructure initiator mass spectrometry (oxime-NIMS) to determine soluble sugar products of their reactions. Single, purified enzymes from the GH5_4, GH10, and GH11 families of glycoside hydrolases hydrolyzed hemicelluloses as evidenced by the loss ofmore » specific epitopes from the glycome profiles in enzyme-treated plant biomass. The glycome profiling data were further substantiated by oxime-NIMS, which identified hexose products from hydrolysis of cellulose, and pentose-only and mixed hexose-pentose products from the hydrolysis of hemicelluloses. The GH10 enzyme proved to be reactive with the broadest diversity of xylose-backbone polysaccharide epitopes, but was incapable of reacting with glucose-backbone polysaccharides. In contrast, the GH5 and GH11 enzymes studied here showed the ability to react with both glucose- and xylose-backbone polysaccharides. The identification of enzyme specificity for a wide diversity of polysaccharide structures provided by glycome profiling, and the correlated identification of soluble oligosaccharide hydrolysis products provided by oxime-NIMS, offers a unique combination to understand the hydrolytic capabilities and constraints of individual enzymes as they interact with plant biomass.« less

Determination of glycoside hydrolase specificities during hydrolysis of plant cell walls using glycome profiling

DOE PAGES

Walker, Johnnie A.; Pattathil, Sivakumar; Bergeman, Lai F.; ...

2017-02-02

Glycoside hydrolases (GHs) are enzymes that hydrolyze polysaccharides into simple sugars. To better understand the specificity of enzyme hydrolysis within the complex matrix of polysaccharides found in the plant cell wall, we studied the reactions of individual enzymes using glycome profiling, where a comprehensive collection of cell wall glycan-directed monoclonal antibodies are used to detect polysaccharide epitopes remaining in the walls after enzyme treatment and quantitative nanostructure initiator mass spectrometry (oxime-NIMS) to determine soluble sugar products of their reactions. Single, purified enzymes from the GH5_4, GH10, and GH11 families of glycoside hydrolases hydrolyzed hemicelluloses as evidenced by the loss ofmore » specific epitopes from the glycome profiles in enzyme-treated plant biomass. The glycome profiling data were further substantiated by oxime-NIMS, which identified hexose products from hydrolysis of cellulose, and pentose-only and mixed hexose-pentose products from the hydrolysis of hemicelluloses. The GH10 enzyme proved to be reactive with the broadest diversity of xylose-backbone polysaccharide epitopes, but was incapable of reacting with glucose-backbone polysaccharides. In contrast, the GH5 and GH11 enzymes studied here showed the ability to react with both glucose- and xylose-backbone polysaccharides. The identification of enzyme specificity for a wide diversity of polysaccharide structures provided by glycome profiling, and the correlated identification of soluble oligosaccharide hydrolysis products provided by oxime-NIMS, offers a unique combination to understand the hydrolytic capabilities and constraints of individual enzymes as they interact with plant biomass.« less

Biosynthesis of the Cyanogenic Glucosides Linamarin and Lotaustralin in Cassava: Isolation, Biochemical Characterization, and Expression Pattern of CYP71E7, the Oxime-Metabolizing Cytochrome P450 Enzyme1[OA

PubMed Central

Jørgensen, Kirsten; Morant, Anne Vinther; Morant, Marc; Jensen, Niels Bjerg; Olsen, Carl Erik; Kannangara, Rubini; Motawia, Mohammed Saddik; Møller, Birger Lindberg; Bak, Søren

2011-01-01

Cassava (Manihot esculenta) is a eudicotyledonous plant that produces the valine- and isoleucine-derived cyanogenic glucosides linamarin and lotaustralin with the corresponding oximes and cyanohydrins as key intermediates. CYP79 enzymes catalyzing amino acid-to-oxime conversion in cyanogenic glucoside biosynthesis are known from several plants including cassava. The enzyme system converting oxime into cyanohydrin has previously only been identified in the monocotyledonous plant great millet (Sorghum bicolor). Using this great millet CYP71E1 sequence as a query in a Basic Local Alignment Search Tool-p search, a putative functional homolog that exhibited an approximately 50% amino acid sequence identity was found in cassava. The corresponding full-length cDNA clone was obtained from a plasmid library prepared from cassava shoot tips and was assigned CYP71E7. Heterologous expression of CYP71E7 in yeast afforded microsomes converting 2-methylpropanal oxime (valine-derived oxime) and 2-methylbutanal oxime (isoleucine-derived oxime) to the corresponding cyanohydrins, which dissociate into acetone and 2-butanone, respectively, and hydrogen cyanide. The volatile ketones were detected as 2.4-dinitrophenylhydrazone derivatives by liquid chromatography-mass spectrometry. A KS of approximately 0.9 μm was determined for 2-methylbutanal oxime based on substrate-binding spectra. CYP71E7 exhibits low specificity for the side chain of the substrate and catalyzes the conversion of aliphatic and aromatic oximes with turnovers of approximately 21, 17, 8, and 1 min−1 for the oximes derived from valine, isoleucine, tyrosine, and phenylalanine, respectively. A second paralog of CYP71E7 was identified by database searches and showed approximately 90% amino acid sequence identity. In tube in situ polymerase chain reaction showed that in nearly unfolded leaves, the CYP71E7 paralogs are preferentially expressed in specific cells in the endodermis and in most cells in the first cortex cell layer. In fully unfolded leaves, the expression is pronounced in the cortex cell layer just beside the epidermis and in specific cells in the vascular tissue cortex cells. Thus, the transcripts of the CYP71E7 paralogs colocalize with CYP79D1 and CYP79D2. We conclude that CYP71E7 is the oxime-metabolizing enzyme in cyanogenic glucoside biosynthesis in cassava. PMID:21045121

Tertiary Oximes on Brain Acetylcholinesterase and Central Excitatory Effects of Nerve Agents

DTIC Science & Technology

2012-01-01

5 test doses of the oxime. Animals were euthanized 45 min after oxime treatment when blood and target tissues were collected. AChE activity was...the ability of MINA and DHAP to block or terminate nerve agent-induced electroencephalographic (EEG) seizure activity was evaluated. Animals...instrumented to record brain EEG activity were challenged with a seizure-inducing dose (2.0 x LD50) of GB, GF, or VX, and oxime was administered one min

A case of Z/E-isomers elution order inversion caused by cosolvent percentage change in supercritical fluid chromatography.

PubMed

Pokrovskiy, Oleg I; Ustinovich, Konstantin B; Usovich, Oleg I; Parenago, Olga O; Lunin, Valeriy V; Ovchinnikov, Denis V; Kosyakov, Dmitry S

2017-01-06

A case of elution order inversion caused by cosolvent percentage change in supercritical fluid chromatography was observed and investigated in some detail. Z- and E-isomers of phenylisobutylketone oxime experience an elution order reversal on most columns if the mobile phase consists of CO 2 and alcohol. At lower percentages of alcohol Z-oxime is retained less, somewhere at 2-5% coelution occurs and at larger cosolvent volume elution order reverses - Z-oxime is eluted later than E-oxime. We suppose inversion with CO 2 -ROH phases happens due to a shift in balance between two main interactions governing retention. At low ROH percentages stationary phase surface is only slightly covered by ROH molecules so oximes primarily interact with adsorption sites via hydrogen bond formation. Due to intramolecular sterical hindrance Z-oxime is less able to form hydrogen bonds and consequently is eluted first. At higher percentages alcohols occupy most of strong hydrogen bonding sites on silica surface thus leaving non-specific electrostatic interactions predominantly responsible for Z/E selectivity. Z-oxime has a much larger dipole moment than E-oxime and at these conditions it is eluted later. Additional experimental data with CO 2 -CH 3 CN, hexane-iPrOH and CHF 3 -ROH mobile phases supporting this explanation are presented. Copyright © 2016 Elsevier B.V. All rights reserved.

A rapid, convenient, solventless green approach for the synthesis of oximes using grindstone chemistry.

PubMed

Saikia, Lakhinath; Baruah, Jejiron Maheswari; Thakur, Ashim Jyoti

2011-10-04

Synthesis of oximes is an important reaction in organic chemistry, because these versatile oximes are used for protection, purification, and characterization of carbonyl compounds. Nitriles, amides via Beckmann rearrangement, nitro compounds, nitrones, amines, and azaheterocycles can be synthesised from oximes. They also find applications for selective α-activation. In inorganic chemistry, oximes act as a versatile ligand.Several procedures for the preparation of oximes exist, but, most of them have not addressed the green chemistry issue. They are associated with generation of pollutants, requirement of high reaction temperature, low yields, lack of a generalized procedure, etc. Hence, there is a demand for developing an efficient, convenient, and non-polluting or less polluting alternative method for the preparation of oximes. In this context, bismuth compounds are very useful as they are cheap in general, commercially available, air stable crystalline solids, safe, and non-toxic, hence easy to handle. Carbonyl compounds (aliphatic, heterocyclic, and aromatic) were converted into the corresponding oximes in excellent yields by simply grinding the reactants at room temperature without using any solvent in the presence of Bi2O3. Most importantly, this method minimizes waste disposal problems, provides a simple yet efficient example of unconventional methodology and requires short time. We have developed a novel, quick, environmentally safe, and clean synthesis of aldoximes and ketoximes under solvent-free grinding condition.

Evaluation and Computational Characterization of the Faciliated Transport of Glc Carbon C-1 Oxime Reactivators Across a Blood Brain Barrier Model

DTIC Science & Technology

2013-01-01

parame- ters of these SOxs and the analysis of an additional novel SOx N-[(3- b-D-glucopyranosyloxy) propyl ]-2-pyridiniumaldoxime chloride (8c...penetration across the BBB. Expanding on thework of Heldman et al. [16] we compared their best SOx (N-[(3-b-D-glucopyranosyloxy) propyl ]-4-pyr...idiniumaldoxime chloride (8b)) and a novel SOx of our own design [9] (Fig. 1). Our SOx, N-[(3-b-D-glucopyranosyloxy)octyl]-2-pyr- idiniumaldoxime iodide (13c

Acquisition of a Laser Scanning Confocal Microscope to Examine CNS Activity of Antidotal Oximes and to Enhance Undergraduate Research Training Across the Sciences

DTIC Science & Technology

2016-07-15

Activity of Antidotal Oximes and to Enhance Undergraduate Research Training Across the Sciences The views, opinions and/or findings contained in this...to Examine CNS Activity of Antidotal Oximes and to Enhance Undergraduate Research Training Across the Sciences Report Title The project utilized...examining the ability of antidotal oximes to rescue organophosphate (OP)-induced CNS toxicity and training across the sciences and social sciences at

Reactivation of Plasma Butyrylcholinesterase by Pralidoxime Chloride in Patients Poisoned by WHO Class II Toxicity Organophosphorus Insecticides

PubMed Central

Eddleston, Michael

2013-01-01

Some clinicians assess the efficacy of pralidoxime in organophosphorus (OP) poisoned patients by measuring reactivation of butyrylcholinesterase (BuChE). However, the degree of BuChE inhibition varies by OP insecticide, and it is unclear how well oximes reactivate BuChE in vivo. We aimed to assess the usefulness of BuChE activity to monitor pralidoxime treatment by studying its reactivation after pralidoxime administration to patients with laboratory-proven World Health Organization (WHO) class II OP insecticide poisoning. Patient data were derived from 2 studies, a cohort study (using a bolus treatment of 1g pralidoxime chloride) and a randomized controlled trial (RCT) (comparing 2g pralidoxime over 20min, followed by an infusion of 0.5g/h, with placebo). Two grams of pralidoxime variably reactivated BuChE in patients poisoned by 2 diethyl OP insecticides, chlorpyrifos and quinalphos; however, unlike acetylcholinesterase reactivation, this reactivation was not sustained. It did not reactivate BuChE inhibited by the dimethyl OPs dimethoate or fenthion. The 1-g dose produced no reactivation. Pralidoxime produced variable reactivation of BuChE in WHO class II OP-poisoned patients according to the pralidoxime dose administered, OP ingested, and individual patient. The use of BuChE assays for monitoring the effect of pralidoxime treatment is unlikely to be clinically useful. PMID:24052565

Functional Consequences of Repeated Organophosphate Exposure: Potential Non-Cholinergic Mechanisms

PubMed Central

Terry, A.V.

2012-01-01

The class of chemicals known as the “organophosphates” (OPs) comprises many of the most common agricultural and commercial pesticides that are used worldwide as well as the highly toxic chemical warfare agents. The mechanism of the acute toxicity of OPs in both target and non-target organisms is primarily attributed to inhibitory actions on various forms of cholinesterase leading to excessive peripheral and central cholinergic activity. However, there is now substantial evidence that this canonical (cholinesterase-based) mechanism cannot alone account for the wide-variety of adverse consequences of OP exposure that have been described, especially those associated with repeated exposures to levels that produce no overt signs of acute toxicity. This type of exposure has been associated with prolonged impairments in attention, memory, and other domains of cognition, as well as chronic illnesses where these symptoms are manifested (e.g., Gulf War Illness, Alzheimer’s disease). Due to their highly reactive nature, it is not surprising that OPs might alter the function of a number of enzymes and proteins (in addition to cholinesterase). However, the wide variety of long-term neuropsychiatric symptoms that have been associated with OPs suggests that some basic or fundamental neuronal process was adversely affected during the exposure period. The purpose of this review is to discuss several non-cholinesterase targets of OPs that might affect such fundamental processes and includes cytoskeletal and motor proteins involved in axonal transport, neurotrophins and their receptors, and mitochondria (especially their morphology and movement in axons). Potential therapeutic implications of these OP interactions are also discussed. PMID:22465060

Identifying motor and sensory myelinated axons in rabbit peripheral nerves by histochemical staining for carbonic anhydrase and cholinesterase activities

NASA Technical Reports Server (NTRS)

Riley, Danny A.; Sanger, James R.; Matloub, Hani S.; Yousif, N. John; Bain, James L. W.

1988-01-01

Carbonic anhydrase (CA) and cholinesterase (CE) histochemical staining of rabbit spinal nerve roots and dorsal root ganglia demonstrated that among the reactive myeliated axons, with minor exceptions, sensory axons were CA positive and CE negative whereas motor axons were CA negative and CE positive. The high specificity was achieved by adjusting reaction conditions to stain subpopulations of myelinated axons selectively while leaving 50 percent or so unstained. Fixation with glutaraldehyde appeared necessary for achieving selectivity. Following sciatic nerve transection, the reciprocal staining pattern persisted in damaged axons and their regenerating processes which formed neuromas within the proximal nerve stump. Within the neuromas, CA-stained sensory processes were elaborated earlier and in greater numbers than CE-stained regenerating motor processes. The present results indicate that histochemical axon typing can be exploited to reveal heterogeneous responses of motor and sensory axons to injury.

Development of pretreatment compounds against nerve-gas agents. Annual report (Final), 16 May 88-30 Sep 90

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carroll, F.I.; Abraham, P.

1990-09-30

The U. S. Army Medical Research and Development Command is interested in research directed toward the development of countermeasures to chemical warfare (CW) agents such as the nerve gas poison soman. Soman and other nerve gas poisons are extremely potent cholinesterase inhibitors. This inhibition leads to a buildup of excess acetylcholine resulting in over-stimulation of both the peripheral and central nervous system and can lead to death. Standard therapy for organophosphate nerve agent poisoning is based on co-administration of an anticholinergic agent such as atropine to antagonize the effects of accumulated acetylcholine and a cholinesterase reactivator such as 2-PAM tomore » dephosphorylate the inhibited enzyme. However, since many problems remain in the treatment of organophosphate nerve agent poisoning, there is considerable interest and need to develop new pretreatment and treatment drugs, particularly for soman poisoning.« less

S-Esters of Thiohydroximic Acid Esters - A Novel Class of Cholinesterase Reactivators.

DTIC Science & Technology

1981-01-05

Hammet substituent constant ( p)63 is also linear and conforms to equation (5) pKa - (7.63 ±0.02) - 0.63 ±0.05) a (5) p These correlations provide an...of AChE reactivation and it is recognized6, 7 that the reaction proceeds as shown in equation (1) EOP + R [EOP9R] kr P EOH + ROP (1) H20 where: EOH is...conforms to equation (4) pKa (25.3 ±2.1) - (1.36 ±0.16) 6 (4) For the aroylthiohydroximates (SR 2458, 2460, and 2461) a plot (not shown) of pKa versus

Glycoconjugate Oxime Formation Catalyzed at Neutral pH: Mechanistic Insights and Applications of 1,4-Diaminobenzene as a Superior Catalyst for Complex Carbohydrates.

PubMed

Østergaard, Mads; Christensen, Niels Johan; Hjuler, Christian T; Jensen, Knud J; Thygesen, Mikkel B

2018-04-18

The reaction of unprotected carbohydrates with aminooxy reagents to provide oximes is a key method for the construction of glycoconjugates. Aniline and derivatives serve as organocatalysts for the formation of oximes from simple aldehydes, and we have previously reported that aniline also catalyzes the formation of oximes from the more complex aldehydes, carbohydrates. Here, we present a comprehensive study of the effect of aniline analogues on the formation of carbohydrate oximes and related glycoconjugates depending on organocatalyst structure, pH, nucleophile, and carbohydrate, covering more than 150 different reaction conditions. The observed superiority of the 1,4-diaminobenzene (PDA) catalyst at neutral pH is rationalized by NMR analyses and DFT studies of reaction intermediates. Carbohydrate oxime formation at pH 7 is demonstrated by the formation of a bioactive glycoconjugate from a labile, decorated octasaccharide originating from exopolysaccharides of the soil bacterium Mesorhizobium loti. This study of glycoconjugate formation includes the first direct comparison of aniline-catalyzed reaction rates and equilibrium constants for different classes of nucleophiles, including primary oxyamines, secondary N-alkyl oxyamines, as well as aryl and arylsulfonyl hydrazides. We identified 1,4-diaminobenzene as a superior catalyst for the construction of oxime-linked glycoconjugates under mild conditions.

The Oxime Portmanteau Motif: Released Heteroradicals Undergo Incisive EPR Interrogation and Deliver Diverse Heterocycles

PubMed Central

2014-01-01

Conspectus Selective syntheses are now available for compounds of many classes, based on C-centered radicals, exploiting a diverse range of mechanisms. The prospect for chemistry based around N- and O-centered radicals is probably more favorable because of the importance of heterocycles as biologically active materials. Heteroradical chemistry is still comparatively underdeveloped due to the need for safe and easy ways of generating them. Oxime esters appeared promising candidates to meet this need because literature reports and our EPR spectroscopic examinations showed they readily dissociated on photolysis with production of a pair of N- and O-centered radicals. It soon became apparent that a whole suite of benign oxime-containing molecules could be pressed into service. The bimodality of the oxime motif meant that by suitable choice of functionality the reactions could be directed to yield selectively products from either the N-centered radicals or from the O-centered radicals. We found that on one hand photolyses of acetophenone oxime esters of carboxylic acids yielded alicyclics. On the other hand, aromatic and heteroaromatic acyl oximes (as well as dioxime oxalates) afforded good yields of phenanthridines and related heterocycles. Easily prepared oxime oxalate amides released carbamoyl radicals, and pleasingly, β-lactams were thereby obtained. Oxime carbonates and oxime carbamates, available via our novel 1,1'-carbonyldiimidazole (CDI)-based preparations, were accessible alternatives for iminyl radicals and hence for phenanthridine preparations. In their second modes, these compounds proved their value as precursors for exotic alkoxycarbonyloxyl and carbamoyloxyl radicals. Microwave-assistance was shown to be a particularly convenient procedure with O-phenyl oxime ethers. The iminyl radicals generated from such precursors with alkene, alkyne, and aromatic acceptor substituents furnished pyrrole, quinoline, phenanthridine, benzonaphthiridine, indolopyridine, and other systems. Microwave irradiations with 2-(aminoaryl)alkanone O-phenyl oximes enabled either dihydroquinazolines or quinazolines to be obtained in very good yields. The fine quality of the EPR spectra, acquired during photolyses of all the O-carbonyl oxime types, marked this as an important complement to existing ways of obtaining such spectra in solution. Quantifications enabled SARs to be obtained for key reaction types of N- and O-centered radicals, thus putting mechanistic chemistry in this area on a much firmer footing. Surprises included the inverse gem-dimethyl effect in 5-exo-cyclizations of iminyls and the interplay of spiro- with ortho-cyclization onto aromatics. Insights into unusual 4-exo-cyclizations of carbamoyl radicals showed the process to be more viable than pent-4-enyl 4-exo-ring closure. Another surprise was the magnitude of the difference in CO2 loss rate from alkoxycarbonyloxyl radicals as compared with acyloxyl radicals. Their rapid 5-exo-cyclization was charted, as was their preferred spiro-cyclization onto aromatics. The first evidence that N-monosubstituted carbamoyloxyls had finite lifetimes was also forthcoming. It is evident that oxime derivatives have excellent credentials as reagents for radical generation and that there is ample room to extend their applications to additional radical types and for further heterocycle syntheses. There is also clear scope for the development of preparative procedures based around the alkoxyl and aminyl radicals that emerge downstream from oxime carbonate and oxime carbamate dissociations. PMID:24654991

Evaluation of Chemically-Sensitive Field-Effect Transistors for Detection of Organophosphorus Compounds

DTIC Science & Technology

1989-12-05

during past decade. In order to understand the basic operation of these sensors, especially of the CHEMFET, the appropriate background information will...during the past decade for detecting organophosphorus compounds, the chemically- sensitive thin films investigated in this thesis, and finally, the...reactivate the phosphorylated cholinesterase enzyme. Solid State Chemical Sensors During the past decade, a number of solid state chemical sensors have been

Blood Cholinesterase as a Function of Physostigmine.

DTIC Science & Technology

1981-07-01

organophosphates to serum cholines - terase and brain homogenate are similar, indicating that the en- zymes are the same in blood and brain, although...organophosphate insult to the organism. Little research is available on the time course of cholin - esterase inactivation and/or reactivation after...administration. Nine animals received a .05, .07, .09, .11, or .13 mg/kg dose of physostigmine salicylate or a placebo injection on two occasions, and four

Investigation of oxidative stress in blood, brain, kidney, and liver after oxime antidote HI-6 application in a mouse experimental model.

PubMed

Pohanka, Miroslav; Sobotka, Jakub; Svobodova, Hana; Stetina, Rudolf

2011-07-01

Oxime reactivator HI-6 (asoxime, in some sources) is a potent antidote suitable for treatment of intoxication by nerve agents. Despite the fact that HI-6 is considered for practical application in emergency situations, the impact of HI-6 on patients' bodies has not been established yet. The present experiment was carried out in order to estimate whether HI-6 would be able to trigger or protect from oxidative stress in a BALB/c mice model. HI-6 was applied in doses ranging from 0.2 to 20% of LD₅₀. Ferric-reducing antioxidant power (FRAP), thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), and glutathione reductase (GR) were assayed in the blood, liver, kidney, and brain of treated animals. It was found that HI-6 does not increase GR or TBARS. On the contrary, TBARS levels in the brain and liver were found to be significantly decreased in HI-6-treated animals. Pertinent antioxidant properties of HI-6 were excluded by the FRAP method. Endogenous antioxidants were unchanged, with the exception of the kidney. Low-molecular-weight antioxidants assayed by the FRAP method were significantly decreased in kidneys of animals treated with HI-6. However, GSH partially recovered the loss of the other low-molecular-weight antioxidants and was significantly increased in the kidney of HI-6-exposed mice. HI-6 potential to produce nephropathy is hypothesized. The achieved conclusions were quite surprising and showed a complex impact of HI-6 on the body.

Skin decontamination of mustards and organophosphates: comparative efficiency of RSDL and Fuller's earth in domestic swine.

PubMed

Taysse, L; Daulon, S; Delamanche, S; Bellier, B; Breton, P

2007-02-01

Research in skin decontamination and therapy of chemical warfare agents has been a difficult problem due to the simultaneous requirement of rapid action and non-aggressive behaviour. The aim of this study was to compare the performance of two decontaminating systems: the Canadian Reactive Skin Decontaminant Lotion (RSDL) and the Fuller's Earth (FE). The experiment was conducted with domestic swine, as a good model for extrapolation to human skin. RSDL and FE were tested against sulphur mustard (SM), a powerful vesicant, and VX, a potent and persistent cholinesterase inhibitor. When used 5 min after contamination, the results clearly showed that both systems were active against SM (10.1 mg/cm(2)) and VX (0.06 mg/cm(2)). The potency of the RSDL/sponge was statistically better than FE against skin injury induced by SM, observed 3 days post-exposure. RSDL was rather more efficient than FE in reducing the formation of perinuclear vacuoles and inflammation processes in the epidermis and dermis. Against a severe inhibition (67%) of plasmatic cholinesterases induced by VX poisoning, the potencies of the RSDL/sponge and FE were similar. Both systems completely prevented cholinesterase inhibition, which indirectly indicates a prevention of toxic absorption through the skin.

Structural connotations of bioactivity in a series of organophosphinates

NASA Astrophysics Data System (ADS)

King, James W.; Molnar, Stephen P.

Pretreatment before exposure is one of the options for temporarily protecting persons liable to exposure to toxic organophosphorus compounds in agricultural or warfare situations. It is known that organophosphinates interact with neuronal cholinesterases, but that the latter may spontaneously reactivate in time. Before that reactivation, the enzyme is protected against comlexation with organophosphates. In this study, geometrically optimized unitary molecular indices, i.e., the molecular transforms, FTm, FTe, and FTc, indicating general, electronic, and charge properties, respectively, and the analogous normalized molecular moments, Mn, Me, and Mc, were calculated for a number of phosphinates. These indices were subsequently used in correlation trials with spontaneous reactivation percentages at specific elapsed times, as well as in clustering procedures, to evaluate the effect of structure variations on the reactivation percentages. The results of these studies are discussed, as is the effect of the octanol/water partition coefficient on the noted bioactivity.

Cholinergic symptoms with low serum cholinesterase from therapeutic cholinesterase inhibitor toxicity.

PubMed

Leikin, Jerrold B; Braund, Victoria; DesLauris, Carol

2014-07-01

Although cholinesterase inhibitors have been frequently used in the treatment of Alzheimer disease, its effects on serum cholinesterase concentrations have been rarely described. We described significant depression of serum cholinesterase levels due to cholinesterase inhibitor toxicity from redundant use of donepezil and rivastigmine in a 78-year-old man. Recovery of serum cholinesterase level was noted upon drug discontinuation and cholinergic symptom resolution. Serum cholinesterase level can be used as a biomarker for central cholinesterase inhibitor toxicity.

Nitrogen-containing ecdysteroid derivatives vs. multi-drug resistance in cancer: Preparation and antitumor activity of oximes, oxime ethers and a lactam.

PubMed

Vágvölgyi, Máté; Martins, Ana; Kulmány, Ágnes; Zupkó, István; Gáti, Tamás; Simon, András; Tóth, Gábor; Hunyadi, Attila

2018-01-20

Multidrug resistance is a widespread problem among various diseases and cancer is no exception. We had previously described the chemo-sensitizing activity of ecdysteroid derivatives with low polarity on drug susceptible and multi-drug resistant (MDR) cancer cells. We have also shown that these molecules have a marked selectivity towards the MDR cells. Recent studies on the oximation of various steroid derivatives indicated remarkable increase in their antitumor activity, but there is no related bioactivity data on ecdysteroid oximes. In our present study, 13 novel ecdysteroid derivatives (oximes, oxime ethers and a lactam) and one known compound were synthesized from 20-hydroxyecdysone 2,3;20,22-diacetonide and fully characterized by comprehensive NMR techniques revealing their complete 1 H and 13 C signal assignments. The compounds exerted moderate to strong in vitro antiproliferative activity on HeLa, SiHa, MCF-7 and MDA-MB-231 cell lines. Oxime and particularly oxime ether formation strongly increased their inhibitory activity on the efflux of rhodamine 123 by P-glycoprotein (P-gp), while the new ecdysteroid lactam did not interfere with the efflux function. All compounds exerted potent chemo-sensitizing activity towards doxorubicin on a mouse lymphoma cell line and on its MDR counterpart, and, on the latter, the lactam was found the most active. Because of its MDR-selective chemo-sensitizing activity with no functional effect on P-gp, this lactam is of high potential interest as a new lead for further antitumor studies. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

76 FR 12563 - Oral Dosage Form New Animal Drugs; Spinosad and Milbemycin Oxime

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-08

... spinosad and milbemycin oxime in dogs for the treatment and prevention of flea infestations and for the... and milbemycin oxime) Chewable Tablets in dogs for the treatment and prevention of flea infestations... chapter. (c) Conditions of use in dogs--(1) Amount. Administer once a month at a [[Page 12564

Lipophilicity indices derived from the liquid chromatographic behavior observed under bimodal retention conditions (reversed phase/hydrophilic interaction): application to a representative set of pyridinium oximes.

PubMed

Voicu, Victor; Sârbu, Costel; Tache, Florentin; Micăle, Florina; Rădulescu, Ştefan Flavian; Sakurada, Koichi; Ohta, Hikoto; Medvedovici, Andrei

2014-05-01

The liquid chromatographic behavior observed under bimodal retention conditions (reversed phase and hydrophilic interaction) offers a new basis for the determination of some derived lipophilicity indices. The experiments were carried out on a representative group (30 compounds) of pyridinium oximes, therapeutically tested in acetylcholinesterase reactivation, covering a large range of lipophilic character. The chromatographic behavior was observed on a mixed mode acting stationary phase, resulting from covalent functionalization of high purity spherical silica with long chain alkyl groups terminated by a polar environment created through the vicinal diol substitution at the lasting carbon atoms (Acclaim Mixed Mode HILIC 1 column). Elution was achieved by combining different proportions of 5 mM ammonium formiate solutions in water and acetonitrile. The derived lipophilicity indices were compared with logP values resulting from different computational algorithms. The correlations between experimental and computed data sets are significant. To obtain a better insight on the transition from reversed phase to hydrophilic interaction retention mechanisms, the variation of the thermodynamic parameters determined through the van׳t Hoff approach was also discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Water-soluble cationic derivatives of indirubin, the active anticancer component from Indigo naturalis.

PubMed

Ginzinger, Werner; Egger, Alexander; Mühlgassner, Gerhard; Arion, Vladimir B; Jakupec, Michael A; Galanski, Markus; Berger, Walter; Keppler, Bernhard K

2012-10-01

To overcome the problem of poor aqueous solubility and bioavailability of indirubin-3-oximes, the compounds were modified by attaching a quaternary ammonium group at the oxime moiety. Exploring the prodrug concept, an oxime ester with acetyl-l-carnitine was prepared, and the rate of its hydrolysis was investigated to assess its suitability for clinical administration. In addition, the cytotoxic potency of new stable oxime ethers with a choline moiety and their influence on the cell cycle were tested in human cancer cell lines. Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich.

A benzothiazole-based fluorescent probe for hypochlorous acid detection and imaging in living cells

NASA Astrophysics Data System (ADS)

Nguyen, Khac Hong; Hao, Yuanqiang; Zeng, Ke; Fan, Shengnan; Li, Fen; Yuan, Suke; Ding, Xuejing; Xu, Maotian; Liu, You-Nian

2018-06-01

A benzothiazole-based turn-on fluorescent probe with a large Stokes shift (190 nm) has been developed for hypochlorous acid detection. The probe displays prompt fluorescence response for HClO with excellent selectivity over other reactive oxygen species as well as a low detection limit of 0.08 μM. The sensing mechanism involves the HClO-induced specific oxidation of oxime moiety of the probe to nitrile oxide, which was confirmed by HPLC-MS technique. Furthermore, imaging studies demonstrated that the probe is cell permeable and can be applied to detect HClO in living cells.

Cardiac effects of magnesium sulfate pretreatment on acute dichlorvos-induced organophosphate poisoning: an experimental study in rats.

PubMed

Gunay, Nurullah; Kekec, Zeynep; Demiryurek, Seniz; Kose, Ataman; Namiduru, Emine S; Gunay, Nahide E; Sari, Ibrahim; Demiryurek, Abdullah T

2010-02-01

Although atropine and oximes are traditionally used in the management of organophosphate poisoning, investigations have been directed to finding additional therapeutic approaches. Thus, the aim of this study was to evaluate the cardiac effects of magnesium sulfate pretreatment on dichlorvos intoxication in rats. Rats were randomly divided into three groups as control, dichlorvos, and magnesium sulfate groups. After 6 h of dichlorvos or corn oil (as a vehicle) injection, venous blood samples were collected, and cardiac tissue samples were obtained. Biochemical analyses were performed to measure some parameters on serum and cardiac tissue. Immunohistochemical analyses of apoptosis and inducible nitric oxide (NO) synthase showed no change in cardiac tissue. Serum cholinesterase levels were markedly depressed with dichlorvos, and further suppressed markedly with magnesium sulfate pretreatment. Although we have demonstrated that serum NO levels in dichlorvos and magnesium sulfate groups were lower than the control group, cardiac tissue NO levels in magnesium sulfate group were higher than the other two groups. Mortality was not significantly affected with magnesium sulfate pretreatment. Uncertainty still persists on the right strategies for the treatment of organophosphate acute poisoning; however, it was concluded that our results do not suggest that magnesium sulfate therapy is beneficial in the management of acute dichlorvos-induced organophosphate poisoning, and also further studies are required.

Oxime Ethers of (E)-11-Isonitrosostrychnine as Highly Potent Glycine Receptor Antagonists.

PubMed

Mohsen, Amal M Y; Mandour, Yasmine M; Sarukhanyan, Edita; Breitinger, Ulrike; Villmann, Carmen; Banoub, Maha M; Breitinger, Hans-Georg; Dandekar, Thomas; Holzgrabe, Ulrike; Sotriffer, Christoph; Jensen, Anders A; Zlotos, Darius P

2016-12-23

A series of (E)-11-isonitrosostrychnine oxime ethers, 2-aminostrychnine, (strychnine-2-yl)propionamide, 18-oxostrychnine, and N-propylstrychnine bromide were synthesized and evaluated pharmacologically at human α1 and α1β glycine receptors in a functional fluorescence-based and a whole-cell patch-clamp assay and in [ 3 H]strychnine binding studies. 2-Aminostrychnine and the methyl, allyl, and propargyl oxime ethers were the most potent α1 and α1β antagonists in the series, displaying IC 50 values similar to those of strychnine at the two receptors. Docking experiments to the strychnine binding site of the crystal structure of the α3 glycine receptor indicated the same orientation of the strychnine core for all analogues. For the most potent oxime ethers, the ether substituent was accommodated in a lipophilic receptor binding pocket. The findings identify the oxime hydroxy group as a suitable attachment point for linking two strychnine pharmacophores by a polymethylene spacer and are, therefore, important for the design of bivalent ligands targeting glycine receptors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borszeky, K.; Mallat, T.; Aeschiman, R.

The chemo- and enantioselective hydrogenation of pyruvic acid oxime have been studied on Pd/alumina, the latter in the presence of the 1,2-amino alcohol type alkaloids ephedrine, cinchonidine, and cinchonine. High yields of racemic alanine (90-98%) were obtained in the absence of alkaloids in polar solvents at 0-45{degrees}C and 10 bar. Enantioselection increased with higher temperature and alkalid: oxime molar ratio. A 1:1 ephedrine: oxime molar ratio afforded the best enantiomeric excess (26%). The presence of alkaloid resulted in a decrease of reaction rate by a factor of up to 140, compared to the racemic hydrogenation. Based on X-ray crystal structuremore » analysis of the alkaloid-pyruvic acid oxime adduct, a mechanism is proposed for the steric course of the reaction. Extended interactions by multiple H bonds between the adsorbed alkaloid-oxime salt units on the Pd surface is assumed to be at the origin of the moderate enantioselectivity and the very low enantioselective hydrogenation rate. 28 refs., 5 figs., 3 tabs.« less

Pharmacokinetics and Pharmacodynamics of Oximes in Unanesthetized Pigs

DTIC Science & Technology

1991-04-01

D-A234 036 U.S. ARMY MEDICAL RESEARCH p INSTITUTE OF CHEMICAL DEFENSE USAMRICD-TR-91-07 PHARMACOKINETICS AND PHARMACODYNAMICS OF OXIMES IN...SUBJECT TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP 2-PAM Cl, ICD 467, MMB-4, Pharmacokinetics ...Cardiovascular 06 15 Pharmacodynamics, Oximes06 15 19. ABSTRACT (Continue on reverse if necessary and identify by block number) The pharmacokinetics and

Oximes in Acute Organophosphate Pesticide Poisoning: a Systematic Review of Clinical Trials

PubMed Central

Eddleston, Michael; Szinicz, Ladislaus; Eyer, Peter; Buckley, Nick

2006-01-01

Acute organophosphate (OP) pesticide poisoning causes tens of thousands of deaths each year across the developing world. Standard treatment involves the administration of intravenous atropine and oxime to counter acetylcholinesterase inhibition at the synapse. The usefulness of oximes, such as pralidoxime and obidoxime, has however been challenged over the past 20 years by physicians in many parts of the world who have failed to see benefit in their clinical practice. We have carried out a systematic review to find randomised controlled trials (RCTs) of oximes in OP poisoning. Two RCTs have been published involving 182 patients treated with pralidoxime. The RCTs did not find benefit with pralidoxime and have been used to argue that pralidoxime should not be used in OP poisoning. These physicians must be congratulated for attempting important studies in a difficult environment. However, the studies did not take into account recently clarified issues important for outcome and the published methodology is unclear, therefore such a generalised statement cannot be supported by the published results. There are many reasons why oximes may not be relevant in the overwhelming self-poisoning typical of the tropics. However, we believe that a large RCT is required to compare the current WHO-recommended pralidoxime regimen (>30mg/kg bolus followed by >8mg/kg/hr infusion) with placebo to determine definitively the role of oxime therapy in OP self-poisoning. Such a study will need to be designed with pre-defined subgroup analysis to allow the identification of patient subgroups that may benefit from oximes. PMID:11978898

Characterization of plasma cholinesterase in rabbit and evaluation of the inhibitory potential of diazinon.

PubMed

Oropesa, Ana Lourdes; Pérez-López, Marcos; Soler, Francisco

2014-02-01

Several studies indicate that more than one cholinesterase form may be present in the blood of mammals. In this study the predominant plasma cholinesterase activity, the physiological cholinesterase activity as well as cholinesterase sex-dependent changes in non-exposed individuals of rabbit have been established. Plasma cholinesterase was characterized using three substrates (acetylthiocholine iodide, propionylthiocholine iodide, and S-butyrylthiocholine iodide) and three cholinesterase inhibitors (eserine sulfate, BW284C51 and iso-OMPA). The results indicated that propionylthiocholine was the preferred substrate by plasma cholinesterase followed by acetylthiocholine and butyrylthiocholine, and the predominant enzymatic activity was acetylcholinesterase. Physiological plasma cholinesterase activity was 198.9 ± 5.8 nmol/min/ml for male and 205.2 ± 5.0 nmol/min/ml for female using acetylthiocholine as substrate. Thus, sex had no significant effect on the physiological cholinesterase activity (p>0.05). In addition, the in vivo and in vitro sensitivity of plasma cholinesterase to diazinon was also investigated. In rabbits exposed to single doses of diazinon (25 or 125 mg/kg) the higher inhibitions of plasma cholinesterase were reached 9h after oral administration (53% and 87% inhibition, respectively). Cholinesterase activity significantly recovered up to values similar to pre-administration between 3 and 7d depending on the administered dose and sex of the animals. Plasma cholinesterase activity decreased to 24%, 53% and 74% of the initial activity at 9h of in vitro exposure to 1.25, 3.13 and 6.25mg/l of diazinon, respectively, and it remained steadily depressed throughout the experimental period (10d). This study has demonstrated the sensitivity of cholinesterase activity in plasma of rabbits following both in vivo and in vitro exposure to sub-lethal concentrations of diazinon. © 2013 Published by Elsevier Inc.

A Structure-Activity Analysis of the Variation in Oxime Efficacy Against Nerve Agents

DTIC Science & Technology

2008-01-01

Literature 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER A structure- activity analysis of the variation in oxime...structure– activity analysis of the variation in oxime efficacy against nerve agents☆ Donald M. Maxwell a,⁎, Irwin Koplovitz a, Franz Worek b, Richard E...structure– activity analysi Received 22 February 2008 Revised 8 April 2008 Accepted 13 April 2008 Available online 22 April 2008 Keywords: Organophosphorus

A novel microreactor approach for analysis of ketones and aldehydes in breath.

PubMed

Fu, Xiao-An; Li, Mingxiao; Biswas, Souvik; Nantz, Michael H; Higashi, Richard M

2011-11-21

We report a fabricated microreactor with thousands of micropillars in channels. Each micropillar surface is chemically functionalized to selectively preconcentrate gaseous ketones and aldehydes of exhaled breath and to enhance ultra-trace, rapid analysis by direct-infusion Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometry (MS). The micropillar reactive coating contains the quaternary ammonium aminooxy salt 2-(aminooxy)ethyl-N,N,N-trimethylammonium iodide (ATM) for capturing trace carbonyl VOCs by means of an oximation reaction. We demonstrate the utility of this approach for detection of C(1) to C(12) aldehydes and ketones in exhaled breath, but the approach is applicable to any gaseous sample.

Rapid End-Group Modification of Polysaccharides for Biomaterial Applications in Regenerative Medicine.

PubMed

Bondalapati, Somasekhar; Ruvinov, Emil; Kryukov, Olga; Cohen, Smadar; Brik, Ashraf

2014-09-15

Polysaccharides have emerged as important functional materials because of their unique properties such as biocompatibility, biodegradability, and availability of reactive sites for chemical modifications to optimize their properties. The overwhelming majority of the methods to modify polysaccharides employ random chemical modifications, which often improve certain properties while compromising others. On the other hand, the employed methods for selective modifications often require excess of coupling partners, long reaction times and are limited in their scope and wide applicability. To circumvent these drawbacks, aniline-catalyzed oxime formation is developed for selective modification of a variety of polysaccharides through their reducing end. Notably, it is found that for efficient oxime formation, different conditions are required depending on the composition of the specific polysaccharide. It is also shown how our strategy can be applied to improve the physical and functional properties of alginate hydrogels, which are widely used in tissue engineering and regenerative medicine applications. While the randomly and selectively modified alginate exhibits similar viscoelastic properties, the latter forms significantly more stable hydrogel and superior cell adhesive and functional properties. Our results show that the developed conjugation reaction is robust and should open new opportunities for preparing polysaccharide-based functional materials with unique properties. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dynamic Mechanism of a Fluorinated Oxime Reactivator Unbinding from AChE Gorge in Polarizable Water.

PubMed

Pathak, Arup K; Bandyopadhyay, Tusar

2018-04-12

A well-tempered metadynamics simulation is performed to study the unbinding process of a fluorinated oxime (FHI-6) drug from the active-site gorge of acetylcholinesterase enzyme in a polarizable water medium. Cation-π interactions and water bridge and hydrogen bridge formations between the protein and the drug molecule are found to strongly influence the unbinding process, forming basins and barriers along the gorge pathway. Distinct unbinding pathways are found when FHI-6 was compared with its recently reported nonfluorinated analogue, HI-6. For example, because of permanent positive charges on both the pyridinium rings of HI-6, it exhibits the minimum in the potential of mean force of the unbinding process in the gorge mouth (where the peripheral anion site, PAS, of the enzyme is located), which is largely caused by cation-π interactions. However, the same interaction, both in the catalytic active-site (CAS) and PAS regions, is found to be greatly enhanced in its lipophilic fluorinated analogue, FHI-6, causing a deep potential energy minimum in the bound state. This may render FHI-6 to be held more firmly in the CAS region of the gorge, as is also evidenced from the microkinetics of unbinding transitions, measured through a combination of metadynamics and hyperdynamics simulations.

Inhibition of acetylcholinesterase by (1S,3S)-isomalathion proceeds with loss of thiomethyl: kinetic and mass spectral evidence for an unexpected primary leaving group.

PubMed

Doorn, J A; Gage, D A; Schall, M; Talley, T T; Thompson, C M; Richardson, R J

2000-12-01

Previous work demonstrated kinetically that inhibition of mammalian acetylcholinesterase (AChE) by (1S)-isomalathions may proceed by loss of thiomethyl instead of the expected diethyl thiosuccinate as the primary leaving group followed by one of four possible modes of rapid aging. This study sought to identify the adduct that renders AChE refractory toward reactivation after inhibition with the (1S, 3S)-stereoisomer. Electric eel acetylcholinesterase (EEAChE) was inhibited with the four stereoisomers of isomalathion, and rate constants for spontaneous and oxime-mediated reactivation (k(3)) were measured. Oxime-mediated k(3) values were >25-fold higher for enzyme inhibited by (1R)- versus (1S)-stereoisomers with the greatest contrast between the (1R,3R)- and (1S,3S)-enantiomers. EEAChE inactivated by (1R,3R)-isomalathion reactivated spontaneously and in the presence of pyridine-2-aldoxime methiodide (2-PAM) with k(3) values of 1.88 x 10(5) and 4.18 x 10(5) min(-)(1), respectively. In contrast, enzyme treated with the (1S,3S)-enantiomer had spontaneous and 2-PAM-mediated k(3) values of 0 and 6.05 x 10(3) min(-)(1), respectively. The kinetic data that were measured were consistent with those obtained for mammalian AChE used in previous studies. Identification of the adduct that renders EEAChE stable toward reactivation after inhibition with (1S,3S)-isomalathion was accomplished using a peptide mass mapping approach with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). A peak with a mass corresponding to the active site peptide containing the catalytic Ser with a covalently bound O-methyl phosphate adduct was found in the mass spectra of (1S, 3S)-treated EEAChE but not control samples. Identities of the modified active site peptide and adduct were confirmed by fragmentation in MALDI-TOF-MS post-source decay (PSD) analysis, and peaks corresponding to the loss of an adduct as phosphorous/phosphoric acid methyl ester were observed. The results demonstrate that inhibition of EEAChE by (1S,3S)-isomalathion proceeds with loss of thiomethyl as the primary leaving group followed by rapid expulsion of diethyl thiosuccinate as the secondary leaving group to yield an aged enzyme.

Searching for the Cases of Acute Organophosphorus Pesticides Poisoning by JOIS

NASA Astrophysics Data System (ADS)

Futagami, Kojiro; Fujii, Toshiyuki; Horioka, Masayoshi; Asakura, Hajime; Fukagawa, Mitsuro

Cholinesterase reactivator PAM (Pralidoxime) is used in the treatment of organophosphates poisoning with anticholinergic agent atropine. However, some reports demonstrated recently that PAM has inefficacy in some cases of so-called low toxicity organophosphates poisoning. So, to atempt to discuss the efficacy of PAM in clinical treatment, we searched for the case reports of these poisoning by JOIS. In this time, we compared with the specificity of each data bases and presented some examples in this on-line information retrieval.

Probing the reactivation process of sarin-inhibited acetylcholinesterase with α-nucleophiles: hydroxylamine anion is predicted to be a better antidote with DFT calculations.

PubMed

Khan, Md Abdul Shafeeuulla; Lo, Rabindranath; Bandyopadhyay, Tusar; Ganguly, Bishwajit

2011-08-01

Inactivation of acetylcholinesterase (AChE) due to inhibition by organophosphorus (OP) compounds is a major threat to human since AChE is a key enzyme in neurotransmission process. Oximes are used as potential reactivators of OP-inhibited AChE due to their α-effect nucleophilic reactivity. In search of more effective reactivating agents, model studies have shown that α-effect is not so important for dephosphylation reactions. We report the importance of α-effect of nucleophilic reactivity towards the reactivation of OP-inhibited AChE with hydroxylamine anion. We have demonstrated with DFT [B3LYP/6-311G(d,p)] calculations that the reactivation process of sarin-serine adduct 2 with hydroxylamine anion is more efficient than the other nucleophiles reported. The superiority of hydroxylamine anion to reactivate the sarin-inhibited AChE with sarin-serine adducts 3 and 4 compared to formoximate anion was observed in the presence and absence of hydrogen bonding interactions of Gly121 and Gly122. The calculated results show that the rates of reactivation process of adduct 4 with hydroxylamine anion are 261 and 223 times faster than the formoximate anion in the absence and presence of such hydrogen bonding interactions. The DFT calculated results shed light on the importance of the adjacent carbonyl group of Glu202 for the reactivation of sarin-serine adduct, in particular with formoximate anion. The reverse reactivation reaction between hydroxylamine anion and sarin-serine adduct was found to be higher in energy compared to the other nucleophiles, which suggests that this α-nucleophile can be a good antidote agent for the reactivation process. Copyright © 2011 Elsevier Inc. All rights reserved.

Composites of silica with immobilized cholinesterase incorporated into polymeric shell

NASA Astrophysics Data System (ADS)

Payentko, Victoriya; Matkovsky, Alexander; Matrunchik, Yulia

2015-02-01

Synthetic approaches for new nanocomposite materials with relatively high cholinesterase activity have been developed. The peculiarity of the formation of such systems is the introduction of cholinesterase into polymer with subsequent incorporation on the ready-made silica particles and into the polysiloxane matrixes during sol-gel synthesis. Evaluation of the cholinesterase activity has been fulfilled through the imitation of the acetylcholine chloride decomposition reaction. Values of activity for cholinesterase nanocomposites demonstrated in this work are higher than those for the native cholinesterase. The higher activity of cholinesterase contained in nanocomposites was found for those prepared using highly dispersed silica.

Efficacy of afoxolaner plus milbemycin oxime chewable tablets (NexGard Spectra®, Merial) against adult Ancylostoma ceylanicum hookworm, in dogs.

PubMed

Tielemans, E; Lebon, W; Dumont, P; Taweethavonsawat, P; Larsen, D; Rehbein, S

2017-04-30

A fixed-combination chewable tablet incorporating afoxolaner plus milbemycin oxime (NexGard Spectra ® , Merial) was tested in purpose-bred Beagle dogs for efficacy against adult Ancylostoma ceylanicum hookworms. Sixteen dogs were inoculated each by oral administration of approximately 500 infective larvae of A. ceylanicum. Seventeen days after inoculation, the dogs were weighed and allocated randomly to be treated with afoxolaner plus milbemycin oxime chewable tablets or to remain untreated. Commercial chewable tablets of different strength were combined to deliver doses as close as possible to the minimum effective dose of 2.5mg afoxolaner plus 0.5mg milbemycin oxime per kg body weight. Parasites were recovered and counted for determination of efficacy seven days after treatment. All eight dogs that had been left untreated were harboring adult A. ceylanicum (geometric mean, 317.8; range, 210-428) while only one and nine A. ceylanicum were recovered from two of the eight dogs treated with afoxolaner plus milbemycin oxime chewable tablets (geometric mean, 0.5; p<0.0001). Thus, 99.9% efficacy against induced infection of A. ceylanicum was obtained by the use of oral NexGard Spectra ® at the minimum effective dose. Treatment with afoxolaner plus milbemycin oxime chewable tablets was well accepted and safe. Copyright © 2017 Elsevier B.V. All rights reserved.

Cholinesterase activity in Japanese quail dusted with carbaryl

USGS Publications Warehouse

Hill, E.F.

1979-01-01

Japanese quail (Coturnix coturnix japonica) were dusted with 5% carbaryl to determine if this topical treatment would alter plasma and brain cholinesterase activities. Within 6 hours after dusting, plasma cholinesterase activity was depressed compared with controls, the depression averaging 20% for females and 27% for males. By 24 hours the cholinesterase activity of females had returned to normal, but the cholinesterase activity of males remained depressed. Brain cholinesterase activity was not affected by the treatment, and there were no overt toxic signs.

Kinetic Resolution of α-Hydroxy-Substituted Oxime Ethers by Enantioselective Cu-H-Catalyzed Si-O Coupling.

PubMed

Dong, Xichang; Kita, Yuji; Oestreich, Martin

2018-04-12

A catalyst-controlled enantioselective alcohol silylation by Cu-H-catalyzed dehydrogenative Si-O coupling of hydroxy groups α to an oxime ether and simple hydrosilanes is reported. The selectivity factors reached in this kinetic resolution are generally high (s≈50), and these reactions thereby provide reliable access to highly enantioenriched α-hydroxy-substituted oxime ethers. The synthetic usefulness of these compounds is also demonstrated. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of Imidazopyridines via Copper-Catalyzed, Formal Aza-[3 + 2] Cycloaddition Reaction of Pyridine Derivatives with α-Diazo Oxime Ethers.

PubMed

Park, Sangjune; Kim, Hyunseok; Son, Jeong-Yu; Um, Kyusik; Lee, Sooho; Baek, Yonghyeon; Seo, Boram; Lee, Phil Ho

2017-10-06

The Cu-catalyzed, formal aza-[3 + 2] cycloaddition reaction of pyridine derivatives with α-diazo oxime ethers in trifluoroethanol was used to synthesize imidazopyridines via the release of molecular nitrogen and elimination of alcohol. These methods enabled modular synthesis of a wide range of N-heterobicyclic compounds such as imidazopyridazines, imidazopyrimidines, and imidazopyrazines with an α-imino Cu-carbenoid generated from the α-diazo oxime ethers and copper.

Anticancer and antiviral effects and inactivation of S-adenosyl-L-homocysteine hydrolase with 5'-carboxaldehydes and oximes synthesized from adenosine and sugar-modified analogues.

PubMed

Wnuk, S F; Yuan, C S; Borchardt, R T; Balzarini, J; De Clercq, E; Robins, M J

1997-05-23

Selectively protected adenine nucleosides were converted into 5'-carboxaldehyde analogues by Moffatt oxidation (dimethyl sulfoxide/dicyclohexylcarbodiimide/dichloroacetic acid) or with the Dess-Martin periodinane reagent. Hydrolysis of a 5'-fluoro-5'-S-methyl-5'-thio (alpha-fluoro thioether) arabinosyl derivative also gave the 5'-carboxaldehyde. Treatment of 5'-carboxaldehydes with hydroxylamine [or O-(methyl, ethyl, and benzyl)hydroxylamine] hydrochloride gave E/Z oximes. Treatment of purified oximes with aqueous trifluoroacetic acid and acetone effected trans-oximation to provide clean samples of 5'-carboxaldehydes. Adenosine (Ado)-5'-carboxaldehyde and its 4'-epimer are potent inhibitors of S-adenosyl-L-homocysteine (AdoHcy) hydrolase. They bind efficiently to the enzyme and undergo oxidation at C3' to give 3'-keto analogues with concomitant reduction of the NAD+ cofactor to give an inactive, tightly bound NADH-enzyme complex (type I cofactor-depletion inhibition). Potent type I inhibition was observed with 5'-carboxaldehydes that contain a ribo cis-2',3'-glycol. Their oxime derivatives are "proinhibitors" that undergo enzyme-catalyzed hydrolysis to release the inhibitors at the active site. The 2'-deoxy and 2'-epimeric (arabinosyl) analogues were much weaker inhibitors, and the 3'-deoxy compounds bind very weakly. Ado-5'-carboxaldehyde oxime had potent cytotoxicity in tumor cell lines and was toxic to normal human cells. Analogues had weaker cytotoxic and antiviral potencies, and the 3'-deoxy compounds were essentially devoid of cytotoxic and antiviral activity.

[To the 80-anniversary of cholinesterase. The cholinesterase club in Sechenov Institute of Evolutionary Physiology and Biochemistry].

PubMed

Rozengart, E V; Basova, N E; Moralev, S N

2012-01-01

For the second half of the XX century, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences was the center of the Russian cholinesterase investigations ("the Russian cholinesterase club"). The close cooperation with chemists-syntheticians of different scientific schools provided success and fruitfulness of this scientific search. All these years, there was preserved dualism of this investigation: a study of the mechanism of functioning and kinetics of cholinesterase catalysis as well as the comparative-enzymological character of studies of cholinesterases of the animals being at different levels of evolutionary development.

Cutaneous exposure to vesicant phosgene oxime: Acute effects on the skin and systemic toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tewari-Singh, Neera, E-mail: Neera.tewari-singh@uc

Phosgene Oxime (CX), an urticant or nettle agent categorized as a vesicant, is a potential chemical warfare and terrorist weapon. Its exposure can result in widespread and devastating effects including high mortality due to its fast penetration and ability to cause immediate severe cutaneous injury. It is one of the least studied chemical warfare agents with no effective therapy available. Thus, our goal was to examine the acute effects of CX following its cutaneous exposure in SKH-1 hairless mice to help establish a relevant injury model. Results from our study show that topical cutaneous exposure to CX vapor causes blanchingmore » of exposed skin with an erythematous ring, necrosis, edema, mild urticaria and erythema within minutes after exposure out to 8 h post-exposure. These clinical skin manifestations were accompanied with increases in skin thickness, apoptotic cell death, mast cell degranulation, myeloperoxidase activity indicating neutrophil infiltration, p53 phosphorylation and accumulation, and an increase in COX-2 and TNFα levels. Topical CX-exposure also resulted in the dilatation of the peripheral vessels with a robust increase in RBCs in vessels of the liver, spleen, kidney, lungs and heart tissues. These events could cause a drop in blood pressure leading to shock, hypoxia and death. Together, this is the first report on effects of CX cutaneous exposure, which could help design further comprehensive studies evaluating the acute and chronic skin injuries from CX topical exposure and elucidate the related mechanism of action to aid in the identification of therapeutic targets and mitigation of injury. - Highlights: • Phosgene oxime cutaneous exposure causes skin blanching, edema and urticaria. • Penetration of phosgene oxime causes dilation of vasculature in internal organs. • Mast cells could play an important role in phosgene oxime-induced skin injury. • Phosgene oxime could induce low blood pressure and hypoxia leading to mortality. • Data is significant for developing a phosgene oxime-induced skin injury model.« less

Free radicals are present in human serum of Catha edulis Forsk (Khat) abusers.

PubMed

Al-Akwa, Ahmed A; Shaher, Monira; Al-Akwa, Sameeha; Aleryani, Samir L

2009-09-25

Khat (Catha edulis Forsk) is a naturally occurring drug with an amphetamine-like structure and action. It has been postulated that amphetamine induces free radical formation. On this basis, we have hypothesized that Khat may promote synthesis of reactive oxygen and nitrogen species in the same way that amphetamine promotes free radical production. Forty male subjects were enrolled in two groups: those with a chronic Khat chewing habit (n=20), and those without a chewing habit (controls; n=20). Both groups were matched with regard to age. Total antioxidant capacity and cholinesterase (AChE) activity were assayed. This study showed that Khat consumption inhibited serum free radical scavenging enzymes, resulting in significant elevations in free radical loads (p=0.01; n=20). We also showed that serum acetyl cholinesterase (AChE) was significantly inhibited in the Khat chewing group (p=0.002; n=20). These results show for the first time that Khat may contribute to high levels of free radicals. In addition, the presence of pesticides in Khat leaves is implicated in the inhibition of AChE activity.

Determination of molybdenum in sea and estuarine water with BETA-naphthoin oxime and neutron activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuathilake, A.I.; Chatt, A.

1980-05-01

An analytical method has been developed for the determination of submicrogram quantities of molybdenum in sea and esturaine water. The method consists of preconcentration of molybdenum with BETA-naphthoin oxime followed by the determination of the element employing neutron activation analysis. Various factors that can influence yield and selectivity of the preconcentration process have been investigated in detail. A comparison study between ..cap alpha..-benzoin oxime and BETA-naphthoin oxime in preconcentrating molybdenum has been carried out using a standard steel sample. The method has been applied to determine molybdenum content of sea and estuarine water. A detection limit of 0.32 ..mu..g Momore » L/sup -1/ seawater has been acheived. The precision and accuracy of the method have been evaluated using an intercomparison fresh water and a biological standard reference material. 1 figure, 9 tables.« less

Assessing the reactivation efficacy of hydroxylamine anion towards VX-inhibited AChE: a computational study.

PubMed

Khan, Md Abdul Shafeeuulla; Ganguly, Bishwajit

2012-05-01

Oximate anions are used as potential reactivating agents for OP-inhibited AChE because of they possess enhanced nucleophilic reactivity due to the α-effect. We have demonstrated the process of reactivating the VX-AChE adduct with formoximate and hydroxylamine anions by applying the DFT approach at the B3LYP/6-311 G(d,p) level of theory. The calculated results suggest that the hydroxylamine anion is more efficient than the formoximate anion at reactivating VX-inhibited AChE. The reaction of formoximate anion and the VX-AChE adduct is a three-step process, while the reaction of hydroxylamine anion with the VX-AChE adduct seems to be a two-step process. The rate-determining step in the process is the initial attack on the VX of the VX-AChE adduct by the nucleophile. The subsequent steps are exergonic in nature. The potential energy surface (PES) for the reaction of the VX-AChE adduct with hydroxylamine anion reveals that the reactivation process is facilitated by the lower free energy of activation (by a factor of 1.7 kcal mol(-1)) than that of the formoximate anion at the B3LYP/6-311 G(d,p) level of theory. The higher free energy of activation for the reverse reactivation reaction between hydroxylamine anion and the VX-serine adduct further suggests that the hydroxylamine anion is a very good antidote agent for the reactivation process. The activation barriers calculated in solvent using the polarizable continuum model (PCM) for the reactivation of the VX-AChE adduct with hydroxylamine anion were also found to be low. The calculated results suggest that V-series compounds can be more toxic than G-series compounds, which is in accord with earlier experimental observations.

The enzymatic hydrolysis of imidazoleacryloylcholine (murexine) and imidazolepropionylcholine (dihydromurexine) by various cholinesterases

PubMed Central

Grelis, M. E.; Tabachnick, I. I. A.

1957-01-01

Several choline esters, including the imidazoleacryloyl and imidazolepropionyl compounds, have been hydrolysed by cholinesterases from various sources. The imidazolepropionyl ester was metabolized by cholinesterases obtained from human plasma, ox spleen, ox serum, and guinea-pig liver, but not by rat liver or bovine red cell cholinesterase. It is suggested the imidazolepropionylcholine or a closely related ester might be the natural substrate for “non-specific” cholinesterase. PMID:13460237

Research on cholinesterases in the Soviet Union and Russia: a historical perspective.

PubMed

Rozengart, Eugene V; Basova, Natalia E; Moralev, Serge N; Lushchekina, Sofya V; Masson, Patrick; Varfolomeev, Sergei D

2013-03-25

Research on cholinesterases and effects of their inhibition in the USSR and Russia since 1930-1940s till present is exposed in historical aspects. The first physiological and toxicological effects of cholinesterase inhibition were reported by Alexander Ginetsinsky during World War II, when academic institutions were evacuated from Leningrad to Kazan. The main scientific schools that initiated research on chemistry, enzymology and physiology of cholinesterases and their inhibitors were leaded by Alexandr and Boris Arbuzovs, Victor Rozengart, Viktor Yakovlev, Michael Michelson, Martin Kabachnik, Mikhail Voronkov, Ivan Knunyants, Alexandr Bretskin and others. They investigated the main physiological effects of cholinesterase inhibitors, and analyzed the catalytic mechanisms of cholinesterases and related enzymes. Their contributions are landmarks in the history of cholinesterase research. At the present time revival of research on cholinesterases in different universities and institutes is vivid, in particular at the Moscow State University, research institutes of Russian Academy of Sciences and Kazan Scientific Center. Copyright © 2013. Published by Elsevier Ireland Ltd.

Cellular Actions and Interactions of Anticholinesterases and Their Antidotes in Mammalian Autonomic Neurons.

DTIC Science & Technology

1985-07-29

significant ( p ɘ.Ol) - 13 - ’ A MeCh t A MeCh A MeCh DFP OluM WASH AMeCh A MeCh A MeCh DFP lmM WASH Fig. 6 Facilitation and depression of muscarinic...N.J. and Karczmar, A.G. 1982. Substance P : A putative sensory transmitter in mammalian autonomic ganglia. Science, 217, 739-741. 22. Kiraly, M., Ma...neurons and on ganglionic transmission; and (2) clarification of the site and mechanism of action of a cholinesterase (ChE) reactivator, pyridinealdoxime

Three oxime ether derivatives: Synthesis, crystallographic study, electronic structure and molecular electrostatic potential calculation

NASA Astrophysics Data System (ADS)

Dey, Tanusri; Praveena, Koduru Sri Shanthi; Pal, Sarbani; Mukherjee, Alok Kumar

2017-06-01

Three oxime ether derivatives, (E)-3-methoxy-4-(prop-2-ynyloxy)-benzaldehyde-O-prop-2-ynyl-oxime (C14H13NO3) (2), benzophenone-O-prop-2-ynyl-oxime (C16H13NO) (3) and (E)-2-chloro-6-methylquinoline-3-carbaldehyde-O-prop-2-ynyl-oxime (C14H11ClN2O) (4), have been synthesized and their crystal structures have been determined. The DFT optimized molecular geometries in 2-4 agree closely with those obtained from the crystallographic study. An interplay of intermolecular Csbnd H⋯O, Csbnd H⋯N, Csbnd H⋯Cl and Csbnd H···π(arene) hydrogen bonds and π···π interactions assembles molecules into a 2D columnar architecture in 2, a 1D molecular ribbon in 3 and a 3D framework in 4. Hirshfeld surface analysis showed that the structures of 2 and 3 are mainly characterized by H⋯H, H⋯C and H⋯O contacts but some contribution of H⋯N and H⋯Cl contacts is also observed in 4. Hydrogen-bond based interactions in 2-4 have been complemented by calculating molecular electrostatic potential (MEP) surfaces. The electronic structures of molecules reveal that the estimated band gap in 3, in which both aldehyde hydrogen atoms of formaldehyde-O-prop-2-ynyl-oxime (1) have been substituted by two benzene rings, is higher than that of 2 and 4 with only one aldehyde hydrogen atom replaced.

A quantum chemical study of molecular properties and QSPR modeling of oximes, amidoximes and hydroxamic acids with nucleophilic activity against toxic organophosphorus agents

NASA Astrophysics Data System (ADS)

Alencar Filho, Edilson B.; Santos, Aline A.; Oliveira, Boaz G.

2017-04-01

The proposal of this work includes the use of quantum chemical methods and cheminformatics strategies in order to understand the structural profile and reactivity of α-nucleophiles compounds such as oximes, amidoximes and hydroxamic acids, related to hydrolysis rate of organophosphates. Theoretical conformational study of 41 compounds were carried out through the PM3 semiempirical Hamiltonian, followed by the geometry optimization at the B3LYP/6-31+G(d,p) level of theory, complemented by Polarized Continuum Model (PCM) to simulate the aqueous environment. In line with the experimental hypothesis about hydrolytic power, the strength of the Intramolecular Hydrogen Bonds (IHBs) at light of the Bader's Quantum Theory of Atoms in Molecules (QTAIM) is related to the preferential conformations of α-nucleophiles. A set of E-Dragon descriptors (1,666) were submitted to a variable selection through Ordered Predictor Selection (OPS) algorithm. Five descriptors, including atomic charges obtained from the Natural Bond Orbitals (NBO) protocol jointly with a fragment index associated to the presence/absence of IHBs, provided a Quantitative Structure-Property Relationship (QSPR) model via Multiple Linear Regression (MLR). This model showed good validation parameters (R2 = 0.80, Qloo2 = 0.67 and Qext2 = 0.81) and allowed the identification of significant physicochemical features on the molecular scaffold in order to design compounds potentially more active against organophosphorus poisoning.

Pre- and post-treatment effect of physostigmine on soman-inhibited human erythrocyte and muscle acetylcholinesterase in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herkert, N.M.; Schulz, S.; Wille, T.

2011-05-15

Standard treatment of organophosphorus (OP) poisoning includes administration of an antimuscarinic (e.g., atropine) and of an oxime-based reactivator. However, successful oxime treatment in soman poisoning is limited due to rapid aging of phosphylated acetylcholinesterase (AChE). Hence, the inability of standard treatment procedures to counteract the effects of soman poisoning resulted in the search for alternative strategies. Recently, results of an in vivo guinea pig study indicated a therapeutic effect of physostigmine given after soman. The present study was performed to investigate a possible pre- and post-treatment effect of physostigmine on soman-inhibited human AChE given at different time intervals before ormore » after perfusion with soman by using a well-established dynamically working in vitro model for real-time analysis of erythrocyte and muscle AChE. The major findings were that prophylactic physostigmine prevented complete inhibition of AChE by soman and resulted in partial spontaneous recovery of the enzyme by decarbamylation. Physostigmine given as post-treatment resulted in a time-dependent reduction of the protection from soman inhibition and recovery of AChE. Hence, these date indicate that physostigmine given after soman does not protect AChE from irreversible inhibition by the OP and that the observed therapeutic effect of physostigmine in nerve agent poisoning in vivo is probably due to other factors.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parker, B. F.; Hohloch, S.; Pankhurst, J. R.

Vanadium is the main competitor for uranium extraction from seawater, and V( iv ) comprises a minor but important portion of this. V( iv ) undergoes redox reactions with oximes and amidoxime ligands under seawater-relevant conditions, leading to V( v ) complexes and loss of oxime functional groups.

EFFECT OF GAMMA IRRADIATION AND AET ON RAT BLOOD CHOLINESTERASE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, M.W.; Baker, R.D.; Covill, R.W.

1961-03-01

Whole-body gamma irradiation in the rat produced significant whole-blood cholinesterase depression on the tenth day at a dosage level of 75 r. The levels tested when plotted and extrapolared indicated threshold changes in cholinesterase activity would be in the vicinity of 20 to 30 r. AET alone, while producing some mild cholinesterase depression, failed to protect whole-blood cholinesterase activity from the effects of gamma irradiation at the levels of agent and irradiation tested. (auth)

Thioesters for the in vitro evaluation of agents to image brain cholinesterases.

PubMed

Macdonald, Ian R; Jollymore, Courtney T; Reid, G Andrew; Pottie, Ian R; Martin, Earl; Darvesh, Sultan

2013-06-01

Cholinesterases are associated with pathology characteristic of conditions such as Alzheimer's disease and are therefore, considered targets for neuroimaging. Ester derivatives of N-methylpiperidinol are promising potential imaging agents; however, methodology is lacking for evaluating these compounds in vitro. Here, we report the synthesis and evaluation of a series of N-methylpiperidinyl thioesters, possessing comparable properties to their corresponding esters, which can be directly evaluated for cholinesterase kinetics and histochemical distribution in human brain tissue. N-methylpiperidinyl esters and thioesters were synthesized and they demonstrated comparable cholinesterase kinetics. Furthermore, thioesters were capable, using histochemical method, to visualize cholinesterase activity in human brain tissue. N-methylpiperidinyl thioesters can be rapidly evaluated for cholinesterase kinetics and visualization of enzyme distribution in brain tissue which may facilitate development of cholinesterase imaging agents for application to conditions such as Alzheimer's disease.

Distribution and determination of cholinesterases in mammals

PubMed Central

Holmstedt, Bo

1971-01-01

This paper reviews the distribution of cholinesterases in the central nervous system, the ganglia, the striated muscle, and the blood of mammals, and discusses the correlation between the histochemical localization and the function of neuronal cholinesterase. Different methods for the determination of cholinesterase levels are reviewed, with particular reference to their practical value for field work. The Warburg method and the Tintometer and Acholest colorimetric methods are compared on the basis of cholinesterase levels determined in normal persons and in those suffering from parathion intoxication. PMID:4999484

Comparative aspects of the purification and properties of cholinesterases

PubMed Central

Augustinsson, Klas-Bertil

1971-01-01

Recent years have seen great progress in the purification and characterization of cholinesterases. Investigation has indicated the existence of two principal groups: a fairly homogeneous group of acetylcholinesterases and a group of enzymes that utilize butyrylcholine, propionycholine, or benzoylcholine as substrates and that differ widely in their properties. This paper reviews the different types of cholinesterase and their sources, the importance of a proper choice of substrate in cholinesterase studies, methods for the purification of cholinesterases, and some of the properties of these enzymes. PMID:4938026

Application of meta- and para- phenylenediamine as enhanced oxime ligation catalysts for protein labeling, PEGylation, immobilization and release

PubMed Central

Mahmoodi, Mohammad M.; Rashidian, Mohammad; Zhang, Yi; Distefano, Mark D.

2015-01-01

Meta- and para- phenylenediamines have recently been shown to catalyze oxime and hydrazone ligation reactions at rates much faster than aniline, a commonly used catalyst. Here, it is demonstrated how these new catalysts can be used in a generally applicable procedure for fluorescent labeling, PEGylation, immobilization and release of aldehyde and ketone functionalized proteins. The chemical orthogonality of phenylenediamine-catalyzed oxime ligation versus copper catalyzed click reaction has also been harnessed for simultaneous dual labeling of bifunctional proteins containing both aldehyde and alkyne groups in high yield. PMID:25640893

Efficacy of two anthelmintic treatments, spinosad/milbemycin oxime and ivermectin/praziquantel in dogs with natural Toxocara spp. infection.

PubMed

Heredia Cardenas, Rafael; Romero Núñez, Camilo; Miranda Contreras, Laura

2017-11-30

Toxocara canis is one of the most important zoonotic parasites of dogs. The aim of the present study was to compare the efficacy of spinosad/milbemycin oxime and ivermectin/praziquantel in dogs naturally infected with Toxocara spp. We studied 200 dogs with a positive diagnosis of Toxocara spp. Through coproparasitoscopic analysis, two study groups of 100 dogs each were assigned: spinosad/milbemycin oxime at a dose of 30-60mg/kg and 0.75-1.0mg/kg, respectively, or ivermectin/praziquantel administered at a dose of 0.2mg/kg and 5mg/kg, respectively. Both groups received a single dose. Three stool samples, one at day 0 before treatment, and at 14 and 28days post-treatment were examined using concentration-flotation techniques. In both treatments, the number of Toxocara spp. eggs decreased; with spinosad/milbemycin oxime treatment, eggs decreased by 87% at 14days (P=0.008) and 94% at 28days after treatment, compared with 71% at day 14 and 88% at day 28 in dogs medicated with ivermectin/praziquantel. The spinosad/milbemycin oxime treated group showed a greater decrease in the number of Toxocara spp. positive dogs compared to the group receiving ivermectin/praziquantel. Copyright © 2017 Elsevier B.V. All rights reserved.

Oxidation of primary amines to oximes with molecular oxygen using 1,1-diphenyl-2-picrylhydrazyl and WO3/Al2O3 as catalysts.

PubMed

Suzuki, Ken; Watanabe, Tomonari; Murahashi, Shun-Ichi

2013-03-15

The oxidative transformation of primary amines to their corresponding oximes proceeds with high efficiency under molecular oxygen diluted with molecular nitrogen (O2/N2 = 7/93 v/v, 5 MPa) in the presence of the catalysts 1,1-diphenyl-2-picrylhydrazyl (DPPH) and tungusten oxide/alumina (WO3/Al2O3). The method is environmentally benign, because the reaction requires only molecular oxygen as the terminal oxidant and gives water as a side product. Various alicyclic amines and aliphatic amines can be converted to their corresponding oximes in excellent yields. It is noteworthy that the oxidative transformation of primary amines proceeds chemoselectively in the presence of other functional groups. The key step of the present oxidation is a fast electron transfer from the primary amine to DPPH followed by proton transfer to give the α-aminoalkyl radical intermediate, which undergoes reaction with molecular oxygen and hydrogen abstraction to give α-aminoalkyl hydroperoxide. Subsequent reaction of the peroxide with WO3/Al2O3 gives oximes. The aerobic oxidation of secondary amines gives the corresponding nitrones. Aerobic oxidative transformation of cyclohexylamines to cyclohexanone oximes is important as a method for industrial production of ε-caprolactam, a raw material for Nylon 6.

Identification of butyrylcholinesterase adducts after inhibition with isomalathion using mass spectrometry: difference in mechanism between (1R)- and (1S)-stereoisomers.

PubMed

Doorn, J A; Schall, M; Gage, D A; Talley, T T; Thompson, C M; Richardson, R J

2001-10-15

Previous kinetic studies found that butyrylcholinesterase (BChE) inhibited by (1R)-isomalathions readily reactivated, while enzyme inactivated by (1S)-isomers did not. This study tested the hypothesis that (1R)- and (1S)-isomers inhibit BChE by different mechanisms, yielding distinct adducts identifiable by peptide mass mapping with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Equine BChE (EBChE) was inhibited to <10% of control activity with each isomer of isomalathion and the reference compound isoparathion methyl. Control and treated enzyme was digested with trypsin, and peptides were fractionated with HPLC. Separated and unseparated peptides were analyzed with MALDI-TOF-MS. Identity of an organophosphorus peptide adduct was confirmed by fragmentation using postsource decay analysis. EBChE inhibited by (1R)-isomalathions or (S)-isoparathion methyl readily reactivated after oxime treatment with 30-40% activity recovered. Enzyme inactivated by (1S)-isomalathions or (R)-isoparathion methyl recovered <2% and <5% activity, respectively, after oxime treatment. MALDI-TOF-MS analysis revealed that inhibition of EBChE by (1R)-isomalathions and (R)- or (S)-isoparathion methyl yielded O,S-dimethyl phosphate adducts. Enzyme inactivated by (1S)-isomalathions produced only O-methyl phosphate adduct. EBChE modified by (1R)-isomalathions or either enantiomer of isoparathion methyl yielded an O-methyl phosphate adduct as well. The results indicate that EBChE inhibition by (1R)-isomalathions proceeds with loss of diethyl thiosuccinate, but inactivation by (1S)-isomers occurs with loss of thiomethyl as the primary leaving group followed by rapid expulsion of diethyl thiosuccinate to yield an aged enzyme. Furthermore, the data suggest that aging of the O,S-dimethyl phosphate adduct occurs via an S(N)2 process with loss of thiomethyl. Copyright 2001 Academic Press.

Longitudinal Assessment of Blood Cholinesterase Activities over Two Consecutive Years among Latino Non-farmworkers and Pesticide-Exposed Farmworkers in North Carolina

PubMed Central

Quandt, Sara A; Pope, Carey N.; Chen, Haiying; Summers, Phillip; Arcury, Thomas A.

2015-01-01

Objective This study (1) describes patterns of whole blood total cholinesterase, acetylcholinesterase, and butyrylcholinesterase activities across the agricultural season, comparing farmworkers and non-farmworkers; and (2) explores differences between farmworkers' and non-farmworkers' likelihood of cholinesterase depression. Methods Blood samples from 210 Latino male farmworkers and 163 Latino workers with no occupational pesticide exposure collected eight times across two agricultural seasons were analyzed. Mean cholinesterase activity levels and depressions ≥15% were compared by month. Results Farmworkers had significantly lower total cholinesterase and butyrylcholinesterase activities in July and August and lower acetylcholinesterase activity in August. Farmworkers had significantly greater likelihood of cholinesterase depression for each cholinesterase measure across the agricultural season. Significance A repeated-measures design across two years with a non-exposed control group demonstrated anticholinesterase effects in farmworkers. Current regulations designed to prevent pesticide exposure are not effective. PMID:26247638

Amino acid sequence of human cholinesterase. Annual report, 30 September 1984-30 September 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lockridge, O.

1985-10-01

The active-site serine residue is located 198 amino acids from the N-terminal. The active-site peptide was isolated from three different genetic types of human serum cholinesterase: from usual, atypical, and atypical-silent genotypes. It was found that the amino acid sequence of the active-site peptide was identical in all three genotypes. Comparison of the complete sequences of cholinesterase from human serum and acetylcholinesterase from the electric organ of Torpedo californica shows an identity of 53%. Cholinesterase is of interest to the Department of Defense because cholinesterase protects against organophosphate poisons of the type used in chemical warfare. The structural results presentedmore » here will serve as the basis for cloning the gene for cholinesterase. The potential uses of large amounts of cholinesterase would be for cleaning up spills of organophosphates and possibly for detoxifying exposed personnel.« less

Longitudinal Assessment of Blood Cholinesterase Activities Over 2 Consecutive Years Among Latino Nonfarmworkers and Pesticide-Exposed Farmworkers in North Carolina.

PubMed

Quandt, Sara A; Pope, Carey N; Chen, Haiying; Summers, Phillip; Arcury, Thomas A

2015-08-01

This study (1) describes patterns of whole blood total cholinesterase, acetylcholinesterase, and butyrylcholinesterase activities across the agricultural season, comparing farmworkers and nonfarmworkers; and (2) explores differences between farmworkers' and non-farmworkers' likelihood of cholinesterase depression. Blood samples from 210 Latino male farmworkers and 163 Latino workers with no occupational pesticide exposure collected 8 times across 2 agricultural seasons were analyzed. Mean cholinesterase activity levels and depressions 15% or more were compared by month. Farmworkers had significantly lower total cholinesterase and butyrylcholinesterase activities in July and August and lower acetylcholinesterase activity in August. Farmworkers had significantly greater likelihood of cholinesterase depression for each cholinesterase measure across the agricultural season. A repeated-measures design across 2 years with a nonexposed control group demonstrated anticholinesterase effects in farmworkers. Current regulations designed to prevent pesticide exposure are not effective.

Use of procainamide gels in the purification of human and horse serum cholinesterases.

PubMed Central

Ralston, J S; Main, A R; Kilpatrick, B F; Chasson, A L

1983-01-01

Two large-scale methods based primarily on the use of procainamide-Sepharose gels were developed for the purification of horse and human serum non-specific cholinesterases. With method I, the procainamide-Sepharose 4B gel was used in the first step to handle large volumes of serum. With method II, the procainamide-Sepharose 4B gel was used in the final step to obtain pure enzyme. Although both methods gave electrophoretically pure cholinesterase preparations in good yields, they were significantly more efficient at purifying the horse enzyme than the human enzyme. To study this problem, the relative binding of human and horse cholinesterases to procainamide-, methylacridinium (MAC)-, m-trimethylammoniophenyl (m-PTA)- and p-trimethylammoniophenyl (p-PTA)-Sepharose 4B gels were measured, by using two approaches. In one, binding was measured by a procedure involving equilibration of pure cholinesterase in a small volume of diluted gel slurry (4%, v/v). A partially purified preparation of Electrophorus acetylcholinesterase was included. Pure human cholinesterase bound consistently more tightly to each of the gels than did horse cholinesterase, and the acetylcholinesterase appeared to bind the gels 10-100 times more tightly than did the non-specific cholinesterases. The order of binding for the cholinesterases, beginning with the tightest, was: procainamide-Sepharose 4B, MAC-Sepharose 4B, p-PTA-Sepharose 4B and m-PTA-Sepharose 4B. For the acetylcholinesterase the order was: MAC-Sepharose 4B, procainamide-Sepharose 4B, p-PTA-Sepharose 4B and m-PTA-Sepharose 4B. The second approach involved passing native sera or partially purified sera fractions through 1 ml test columns of each of the four affinity gels to determine their retention capacity for the cholinesterases. With these impure samples, the MAC-Sepharose 4B gels proved superior to the procainamide-Sepharose 4B gels at retaining human cholinesterase, but the opposite was true for the horse cholinesterase. PMID:6870822

Brain cholinesterase activities of passerine birds in forests sprayed with cholinesterase inhibiting insecticides

USGS Publications Warehouse

Zinkl, J.G.; Henny, C.J.; Shea, P.J.

1979-01-01

Brain cholinesterase activities were determined in passerines collected from northwestern forests that had been sprayed with trichlorfon, acephate, and carbaryl at 0.56, 1.13 and 2.26 kg/ha. Trichlorfon and carbaryl inhibited cholinesterase activity slightly in only a few birds, primarily canopy dwellers. In contrast, acephate caused marked inhibition of cholinesterase activity in nearly all birds collected. The inhibition was present even 33 days after spraying. Some birds from the acephate-sprayed forests exhibited clinical signs compatible with acute acetylcholinesterase inhibition.

Comparison of methods for measuring cholinesterase inhibition by carbamates

PubMed Central

Wilhelm, K.; Vandekar, M.; Reiner, E.

1973-01-01

The Acholest and tintometric methods are used widely for measuring blood cholinesterase activity after exposure to organophosphorus compounds. However, if applied for measuring blood cholinesterase activity in persons exposed to carbamates, the accuracy of the methods requires verification since carbamylated cholinesterases are unstable. The spectrophotometric method was used as a reference method and the two field methods were employed under controlled conditions. Human blood cholinesterases were inhibited in vitro by four methylcarbamates that are used as insecticides. When plasma cholinesterase activity was measured by the Acholest and spectrophotometric methods, no difference was found. The enzyme activity in whole blood determined by the tintometric method was ≤ 11% higher than when the same sample was measured by the spectrophotometric method. PMID:4541147

Oxime-based linker libraries as a general approach for the rapid generation and screening of multidentate inhibitors

PubMed Central

Bahta, Medhanit; Liu, Fa; Kim, Sung-Eun; Stephen, Andrew G.; Fisher, Robert J.; Burke, Terrence R.

2013-01-01

The described oxime-based library protocol provides detailed procedures for the linkage of aminooxy functionality with aldehyde building blocks that result in the generation of libraries of multidentate inhibitors. Synthesis of inhibitors for protein tyrosine phosphatases (PTPs) and antagonists directed against the human tumor susceptibility gene 101 (Tsg101) are shown as examples. Three steps are involved: a) the design and synthesis of aminooxy platforms; b) tethering with aldehydes to form oxime-based linkages with sufficient purity; and c) direct in vitro biological evaluation of oxime products without purification. Each coupling reaction is a) performed in capped microtubes at room temperature; b) diluted for inhibitory evaluation and c) screened with targets in microplates to provide IC50 or Kd values. The synthesis of the aminooxy platforms takes 3–5 days; tethering with the aldehydes takes 24 h; and inhibition assay of enzymes and protein-protein interactions (PPIs) takes 30 min and 2 h respectively. PMID:22422315

O2 Activation and Double C-H Oxidation by a Mononuclear Manganese(II) Complex.

PubMed

Deville, Claire; Padamati, Sandeep K; Sundberg, Jonas; McKee, Vickie; Browne, Wesley R; McKenzie, Christine J

2016-01-11

A Mn(II) complex, [Mn(dpeo)2](2+) (dpeo=1,2-di(pyridin-2-yl)ethanone oxime), activates O2, with ensuing stepwise oxidation of the methylene group in the ligands providing an alkoxide and ultimately a ketone group. X-ray crystal-structure analysis of an intermediate homoleptic alkoxide Mn(III) complex shows tridentate binding of the ligand via the two pyridyl groups and the newly installed alkoxide moiety, with the oxime group no longer coordinated. The structure of a Mn(II) complex of the final ketone ligand, cis-[MnBr2(hidpe)2] (hidpe=2-(hydroxyimino)-1,2-di(pyridine-2-yl)ethanone) shows that bidentate oxime/pyridine coordination has been resumed. H2(18)O and (18)O2 labeling experiments suggest that the inserted O atoms originate from two different O2 molecules. The progress of the oxygenation was monitored through changes in the resonance-enhanced Raman bands of the oxime unit. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cholinesterase depression and its association with pesticide exposure across the agricultural season among Latino farmworkers in North Carolina.

PubMed

Quandt, Sara A; Chen, Haiying; Grzywacz, Joseph G; Vallejos, Quirina M; Galvan, Leonardo; Arcury, Thomas A

2010-05-01

Farmworkers can be exposed to a wide variety of pesticides. Assessing cholinesterase activity over time can be used to monitor exposure to organophosphorus and carbamate pesticides. The goal of this study was to document patterns and variation in cholinesterase levels across the agricultural season (May-August) among field-workers, and to explore the association of cholinesterase depression with pesticide exposure across the agricultural season. Dried blood samples collected from 231 migrant farmworkers sampled from camps in eastern North Carolina up to four times across a summer agricultural season were analyzed for cholinesterase activity, and urine samples were analyzed for metabolites of organophosphorus and carbamate pesticides. Reductions of >or= 15% from an individual's highest value were identified and considered evidence of meaningful cholinesterase activity depression. The average cholinesterase activity levels were lowest in June, with significantly higher mean values in July and August. When adjusted for age, sex, minutes waited to shower, and days worked in the fields, the number of organophosphorus and carbamate pesticides detected in urine predicted reductions in cholinesterase activity. These data demonstrate that workers are experiencing pesticide exposure. Greater enforcement of existing safety regulations or strengthening of these regulations may be warranted. This study demonstrates that serial measurements of cholinesterase activity across an agricultural season can detect exposure to pesticides among field-workers.

Cholinesterase Depression and Its Association with Pesticide Exposure across the Agricultural Season among Latino Farmworkers in North Carolina

PubMed Central

Quandt, Sara A.; Chen, Haiying; Grzywacz, Joseph G.; Vallejos, Quirina M.; Galvan, Leonardo; Arcury, Thomas A.

2010-01-01

Background Farmworkers can be exposed to a wide variety of pesticides. Assessing cholinesterase activity over time can be used to monitor exposure to organophosphorus and carbamate pesticides. Objectives The goal of this study was to document patterns and variation in cholinesterase levels across the agricultural season (May–August) among field-workers, and to explore the association of cholinesterase depression with pesticide exposure across the agricultural season. Methods Dried blood samples collected from 231 migrant farmworkers sampled from camps in eastern North Carolina up to four times across a summer agricultural season were analyzed for cholinesterase activity, and urine samples were analyzed for metabolites of organophosphorus and carbamate pesticides. Reductions of ≥ 15% from an individual’s highest value were identified and considered evidence of meaningful cholinesterase activity depression. Results The average cholinesterase activity levels were lowest in June, with significantly higher mean values in July and August. When adjusted for age, sex, minutes waited to shower, and days worked in the fields, the number of organophosphorus and carbamate pesticides detected in urine predicted reductions in cholinesterase activity. Conclusions These data demonstrate that workers are experiencing pesticide exposure. Greater enforcement of existing safety regulations or strengthening of these regulations may be warranted. This study demonstrates that serial measurements of cholinesterase activity across an agricultural season can detect exposure to pesticides among field-workers. PMID:20085857

Addition of nitromethane to a disilene and a digermene: comparison to surface reactivity and the facile formation of 1,3,2-dioxazolidines.

PubMed

Tashkandi, Nada Y; Parsons, Frederick; Guo, Jiacheng; Baines, Kim M

2015-01-26

The addition of nitromethane to tetramesityldisilene and tetramesityldigermene leads to the formation of the novel 1,3,2,4,5-dioxazadisil- and digermolidine ring systems, respectively. The 1,3,2,4,5-dioxazadisilolidine isomerizes to the 1,4,2,3,5-dioxazadisilolidine ring system, whereas the 1,3,2,4,5-dioxazadigermolidine undergoes ring opening to the isomeric oxime. The preferential formation of the 1,3,2,4,5-dioxazadisilolidine, and its rearrangement to a 1,4,2,3,5-dioxazadisilolidine, provides support for the suggested reaction pathway between nitromethane and the Si(100) 2×1 reconstructed surface. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cholinesterases, a target of pharmacology and toxicology.

PubMed

Pohanka, Miroslav

2011-09-01

Cholinesterases are a group of serine hydrolases that split the neurotransmitter acetylcholine (ACh) and terminate its action. Of the two types, butyrylcholinesterase and acetylcholinesterase (AChE), AChE plays the key role in ending cholinergic neurotransmission. Cholinesterase inhibitors are substances, either natural or man-made that interfere with the break-down of ACh and prolong its action. Hence their relevance to toxicology and pharmacology. The present review summarizes current knowledge of the cholinesterases and their inhibition. Particular attention is paid to the toxicology and pharmacology of cholinesterase-related inhibitors such as nerve agents (e.g. sarin, soman, tabun, VX), pesticides (e.g. paraoxon, parathion, malathion, malaoxon, carbofuran), selected plants and fungal secondary metabolites (e.g. aflatoxins), drugs for Alzheimer's disease (e.g. huperzine, metrifonate, tacrine, donepezil) and Myasthenia gravis (e.g. pyridostigmine) treatment and other compounds (propidium, ethidium, decamethonium). The crucial role of the cholinesterases in neural transmission makes them a primary target of a large number of cholinesterase-inhibiting drugs and toxins. In pharmacology, this has relevance to the treatment of neurodegenerative disorders.

Photosensitized regeneration of carbonyl compounds from oximes.

PubMed

de Lijser, H J Peter; Fardoun, Fadia H; Sawyer, Jody R; Quant, Michelle

2002-07-11

[reaction: see text] Deprotection of oximes to their corresponding carbonyl compounds through the use of photosensitized electron-transfer reactions proceeds in reasonable to good yields. Better yields are obtained in nonpolar solvents and when triplet sensitizers are used. Preliminary mechanistic studies suggest the involvement of an iminoxyl radical.

Plasma cholinesterase activity of rats, western grey kangaroos, alpacas, sheep, cattle, and horses.

PubMed

Mayberry, Chris; Mawson, Peter; Maloney, Shane K

2015-01-01

Plasma cholinesterase activity levels of various species may be of interest to toxicologists or pathologists working with chemicals that interfere with the activity of plasma cholinesterase. We used a pH titration method to measure the plasma cholinesterase activity of six mammalian species. Plasma cholinesterase activity varied up to 50-fold between species: sheep (88 ± 45 nM acetylcholine degraded per ml of test plasma per minute), cattle (94 ± 35), western grey kangaroos (126 ± 92), alpaca (364 ± 70), rats (390 ± 118) and horses (4539 ± 721). We present a simple, effective technique for the assay of plasma cholinesterase activity levels from a range of species. Although labour-intensive, it requires only basic laboratory equipment. Copyright © 2015 Elsevier Inc. All rights reserved.

[The reversible inhibition of cholinesterases from different biological sources by phosphonium betaines].

PubMed

Zhuzhovskiĭ, Iu G; Kuznetsova, L P; Sochilina, E E; Dmitrieva, E N; Gololobov, Iu G; Bykovskaia, E Iu

1996-01-01

The action of some phosphonium betains on cholinesterases from different biological sources has been studied. It has been shown, that all studied betains are reversible inhibitors of cholinesterase hydrolysis of acetyltiocholine. Inhibiting action of these compounds on acetylcholinesterases is about ten times weaker that of the majority of known phosphonium salts, while their action on butyrylcholinesterases has no peculiarities. There were found certain differences for each betain compounds in their action on cholinesterases from different biological sources. These results may be used for detail classification of cholinesterases and allow to extend knowledge in comparative enzymology.

Resistance in cholinesterase activity after an acute and subchronic exposure to azinphos-methyl in the freshwater gastropod Biomphalaria straminea.

PubMed

Bianco, Karina; Otero, Sofía; Oliver, Agustina Balazote; Nahabedian, Daniel; Kristoff, Gisela

2014-11-01

Organophosphorous and carbamates insecticides are ones of the most popular classes of pesticides used in agriculture. Its success relies on their high acute toxicity and rapid environmental degradation. These insecticides inhibit cholinesterase and cause severe effects on aquatic non-target species, particularly in invertebrates. Since the properties of cholinesterases may differ between species, it is necessary to characterize them before their use as biomarkers. Also organophosphorous and carbamates inhibit carboxylesterases and the use of both enzymes for biomonitoring is suggested. Azinphos-methyl is an organophosphorous insecticide used in several parts of the word. In Argentina, it is the most applied insecticide in fruit production in the north Patagonian region. It was detected with the highest frequency in superficial and groundwater of the region. This work aims to evaluate the sensitivity of B. straminea cholinesterases and carboxylesterases to the OP azinphos-methyl including estimations of 48 h NOEC and IC50 of the pesticide and subchronic effects at environmentally relevant concentrations. These will allow us to evaluate the possibility of using cholinesterase and carboxylesterase of B. straminea as sensitive biomarkers. Previously a partial characterization of these enzymes will be performed. As in most invertebrates, acetylthiocholine was the preferred hydrolyzed substrate of B. straminea ChE, followed by propionylthiocholine and being butyrylthiocholine hydrolysis very low. Cholinesterase activity of B. straminea was significantly inhibited by the selective cholinesterases inhibitor (eserine) and by the selective inhibitor of mammalian acethylcholinesterase (BW284c51). In contrast, iso-OMPA, a specific inhibitor of butyrylcholinesterase, did not inhibit cholinesterase activity. These results suggest that cholinesterase activity in total soft tissue of B. straminea corresponds to acethylcholinesterase. Carboxylesterases activity was one order of magnitude higher than cholinesterase. A greater efficiency (Vmax/Km) was obtained using acetylthiocholine and p-nitrophenyl butyrate. Acute exposure to azinphos-methyl did not cause inhibition of cholinesterase activity until 10 mg L(-1) used. Carboxylesterases towards p-nitrophenyl butyrate was inhibited by azinphos-methyl being the IC502.20±0.75 mg L(-1) of azinphos-methyl. Subchronic exposure to environmental concentrations of azinphos-methyl (0.02 and 0.2 mg L(-1)) produced a decrease in survival, protein content and carboxylesterases activity despite no inhibition of cholinesterase activity was observed. B. straminea cholinesterase is not a sensible biomarker. On the contrary, carboxylesterases activity was inhibited by azinphos-methyl. Carboxylesterases could be protecting cholinesterase activity and therefore, protecting the organism from neurotoxicity. This work confirms the advantages of measuring cholinesterases and carboxylesterases jointly in aquatic biomonitoring of pesticide contamination. This becomes relevant in order to find more sensitive biomarkers and new strategies to protect non-target aquatic organisms from pesticide contamination. Copyright © 2014 Elsevier Inc. All rights reserved.

Organophosphate-Related Alterations in Myelin and Axonal Transport in the Living Mammalian Brain

DTIC Science & Technology

2014-10-01

between blood cholinesterase activity and neurobehavioral deficits (Rohlman et al., 2011). Finally, one additional argument against the premise that AChE...baseline scan (repeated exposure CPF group only). 2.4 Cholinesterase activity Cholinesterase activity was assessed in brain using the method of...Moser VC.2006. Behavioral toxicity of cholinesterase inhibitors. In: Gupta, RC., editor. Toxicology of Organophosphate and Carbamate Compounds

Alkyl group substitution by oxime-bound palladium(II) (the Shaw reaction): Alkly group selectivity and deuterium isotope effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wells, A.P.; Kitching, W.

1992-08-01

This report provides information regarding the selectivity of alkyl groups and the nature of the transition state for C-H palladation by oxime-bound palladium(II) (the Shaw reaction). The kinetic deuterium isotope effects are also presented. 21 refs.

Organic Process Technology Valuation: Cyclohexanone Oxime Syntheses

ERIC Educational Resources Information Center

Cannon, Kevin C.; Breen, Maureen P.

2010-01-01

Three contemporary processes for cyclohexanone oxime synthesis are evaluated in a case study. The case study introduces organic chemistry students to basic cost accounting to determine the most economical technology. Technical and financial aspects of these processes are evaluated with problem-based exercises that may be completed by students…

Weight Loss Associated with Cholinesterase Inhibitors In Patients With Dementia in a National Healthcare System

PubMed Central

Sheffrin, Meera; Miao, Yinghui; Boscardin, W. John; Steinman, Michael A.

2016-01-01

Background/Objectives Inconsistent data from randomized trials suggest cholinesterase inhibitors may cause weight loss. We sought to determine if the initiation of cholinesterase inhibitors is associated with significant weight loss in a real-word clinical setting. Design Retrospective cohort study from 2007-2010, comparing weight loss in patients with dementia newly prescribed cholinesterase inhibitors and patients newly prescribed other chronic medications Setting National Veterans Affairs (VA) data Participants Patients 65 years or older with a diagnosis of dementia who received a new prescription for a cholinesterase inhibitor or other new other chronic medication. Measurements The primary outcome was time to 10 pound weight loss over 12 months. We used propensity score matching patients to control for the likelihood of receiving a cholinesterase inhibitor based on baseline characteristics. Data were analyzed in a priori defined subgroups by age, comorbid burden, and initial weight. Results Of 6,504 patients that met study criteria, 1188 patients started on cholinesterase inhibitors were matched to 2189 patients started on other medications. The propensity-matched cohorts were well balanced on baseline covariates. Patients initiated on cholinesterase inhibitors had a higher risk of weight loss compared to matched controls at 12 months, HR 1.23 (95% CI 1.07 - 1.41). At twelve months, 29.3% of patients on cholinesterase inhibitors had experienced weight loss compared to 22.8% of non-users, corresponding to a number needed to harm of 21.2 (95% CI 12.5 – 71.4) over one year. There were no significant differences across subgroups. Conclusion Patients with dementia started on cholinesterase inhibitors had a higher risk of clinically significant weight loss over a 12-month period compared to matched controls. These results are consistent with the available data from randomized controlled trials. Clinicians should consider the risk of weight loss when prescribing cholinesterase inhibitors. PMID:26234945

Combined effect of short-term dehydration and sublethal acute oral dicrotophos exposure confounds the diagnosis of anticholinesterase exposure in common quail (Coturnix coturnix) using plasma cholinesterase activity.

PubMed

Heffernan, James; Mineau, Pierre; Falk, Ramona; Wickstrom, Mark

2012-07-01

Common Quail (Coturnix coturnix) were subjected to controlled and replicated experiments in the summer of 2008 to investigate the effects of short-term dehydration on cholinesterase activity in brain and plasma and the interaction between dehydration and exposure to the organophosphorus pesticide dicrotophos in these same tissues. Our objective was to determine if dehydration could confound the diagnosis of anticholinesterase exposure using inhibition of cholinesterase activity in quail tissues. The effect of dehydration was quantified using measures of plasma osmolality and hematocrit. Dicrotophos exposure caused significant inhibition of cholinesterase activity in brain, while the effects of dehydration and interaction were not significant. Dehydration caused significant duration-dependent increases in plasma osmolality and hematocrit. Dehydration also caused a significant increase in plasma cholinesterase activity. Variation in the change in plasma cholinesterase activity in response to dehydration was significantly and positively correlated with dehydration-induced variation in both the change in plasma osmolality and the change in hematocrit. These correlations suggest that plasma cholinesterase activity in quail is not limited to plasma but occupies some larger pool of the extracellular fluid volume, and we suggest lymph is part of that pool. The effects of dehydration on plasma cholinesterase activity masked the inhibitory effects of dicrotophos. Here, the combination of dehydration and dicrotophos exposure produced plasma cholinesterase activity that was not significantly different from reference and pre-exposure values, confounding the diagnosis of anticholinesterase exposure in dehydrated, dicrotophos-exposed quail. A method to adjust plasma cholinesterase activities for the confounding effects of dehydration and enable the diagnosis of anticholinesterase exposure in dehydrated, dicrotophos-exposed quail was developed. Clinicians and practitioners responsible for the diagnosis of anticholinesterase exposure in birds are cautioned that dehydration, commonly observed in sick wildlife, may mask the effect of anticholinesterases on plasma cholinesterase activity.

Serum Cholinesterase Is Inversely Associated with Body Weight Change in Men Undergoing Routine Health Screening.

PubMed

Oda, Eiji

2015-01-01

The purpose of this study is to investigate the relationships between serum cholinesterase and body weight change, in addition to incident obesity defined as a body mass index (BMI) of 25 kg/m(2) or greater. A retrospective 5-year follow-up study was conducted. The crude incidence and hazard ratios (HRs) of obesity adjusted for the BMI and other confounders were calculated for cholinesterase quartiles in 1,412 men and 921 women. Partial correlation coefficients (PCCs) were calculated between cholinesterase and changes in the BMI during the 5-year follow-up period adjusted for age and other confounders and the change in the BMI were compared among cholinesterase quartiles in 1,223 men and 681 women. During the 5-year follow-up period, 149 men (10.6%) and 65 women (7.1%) developed obesity. The adjusted HRs of obesity decreased, although the crude incidence of obesity increased along the quartiles of cholinesterase in men. The adjusted HRs of obesity for the first (lowest), second and third quartiles of cholinesterase were 2.02 (p=0.006), 1.45 (p=0.122), and 1.28 (p=0.265), respectively compared with the highest quartile in men. The PCC between the baseline level of cholinesterase and change in the BMI was -0.16 (p<0.001) in men. The mean changes in BMI for 5 years were 0.31 kg/m(2), 0.17 kg/m(2), 0.01 kg/m(2) and -0.04 kg/m(2), respectively in the first, second, third and fourth quartiles of cholinesterase in men (p=0.005). Neither incident obesity nor weight gain was significantly associated with cholinesterase in women. The serum cholinesterase level was inversely associated with body weight change, as well as incident obesity, after adjusted for the BMI in men.

Cholinesterase characterization of two autochthonous species of Ria de Aveiro (Diopatra neapolitana and Solen marginatus) and comparison of sensitivities towards a series of common contaminants.

PubMed

Nunes, Bruno; Resende, Sara Teixeira

2017-05-01

Biomonitoring of chemical contamination requires the use of well-established and validated tools, including biochemical markers that can be potentially affected by exposure to important environmental toxicants. Cholinesterases (ChEs) are present in a large number of species and have been successfully used for decades to discriminate the environmental presence of specific groups of pollutants. The success of cholinesterase inhibition has been due to their usefulness as a biomarker to address the presence of organophosphate (OP) and carbamate (CB) pesticides. However, its use in ecotoxicology has not been limited to such chemicals, and several other putative classes of contaminants have been implicated in cholinesterasic impairment. Nevertheless, the use of cholinesterases as a monitoring tool requires its full characterization in species to be used as test organisms. This study analyzed and differentiated the various cholinesterase forms present in two autochthonous organisms from the Ria de Aveiro (Portugal) area, namely the polychaete Diopatra neapolitana and the bivalve Solen marginatus, to be used in subsequent monitoring studies. In addition, this study also validated the putative use of the now characterized cholinesterasic forms by analyzing the in vitro effects of common anthropogenic contaminants, such as detergents, pesticides, and metals. The predominant cholinesterasic form found in tissues of D. neapolitana was acetylcholinesterase, while homogenates of S. marginatus were shown to possess an atypical cholinesterasic form, with a marked preference for propionylthiocholine. Cholinesterases from D. neapolitana were generally non-responsive towards the majority of the selected chemicals. On the contrary, strong inhibitory effects were reported for ChEs of S. marginatus following exposure to the selected pesticides.

Evaluation of Candidate Genes for Cholinesterase Activity in Farmworkers Exposed to Organophosphorus Pesticides: Association of Single Nucleotide Polymorphisms in BCHE

PubMed Central

Howard, Timothy D.; Hsu, Fang-Chi; Grzywacz, Joseph G.; Chen, Haiying; Quandt, Sara A.; Vallejos, Quirina M.; Whalley, Lara E.; Cui, Wei; Padilla, Stephanie; Arcury, Thomas A.

2010-01-01

Background Organophosphate pesticides act as cholinesterase inhibitors. For those with agricultural exposure to these chemicals, risk of potential exposure-related health effects may be modified by genetic variability in cholinesterase metabolism. Cholinesterase activity is a useful, indirect measurement of pesticide exposure, especially in high-risk individuals such as farmworkers. To understand fully the links between pesticide exposure and potential human disease, analyses must be able to consider genetic variability in pesticide metabolism. Objectives We studied participants in the Community Participatory Approach to Measuring Farmworker Pesticide Exposure (PACE3) study to determine whether cholinesterase levels are associated with single-nucleotide polymorphisms (SNPs) involved in pesticide metabolism. Methods Cholinesterase levels were measured from blood samples taken from 287 PACE3 participants at up to four time points during the 2007 growing season. We performed association tests of cholinesterase levels and 256 SNPs in 30 candidate genes potentially involved in pesticide metabolism. A false discovery rate (FDR) p-value was used to account for multiple testing. Results Thirty-five SNPs were associated (unadjusted p < 0.05) based on at least one of the genetic models tested (general, additive, dominant, and recessive). The strongest evidence of association with cholinesterase levels was observed with two SNPs, rs2668207 and rs2048493, in the butyrylcholinesterase (BCHE) gene (FDR adjusted p = 0.15 for both; unadjusted p = 0.00098 and 0.00068, respectively). In participants with at least one minor allele, cholinesterase levels were lower by 4.3–9.5% at all time points, consistent with an effect that is independent of pesticide exposure. Conclusions Common genetic variation in the BCHE gene may contribute to subtle changes in cholinesterase levels. PMID:20529763

Cholinesterase inhibitors: a patent review (2007 - 2011).

PubMed

de los Ríos, Cristóbal

2012-08-01

Cholinesterase inhibitors participate in the maintenance of the levels of the neurotransmitter acetylcholine by inhibiting the enzymes implicated in its degradation, namely, butyrylcholinesterase and acetylcholinesterase. This pharmacological action has an important role in several diseases, including neurodegenerative diseases such as Alzheimer's. This article reviews recent advances in the development of cholinesterase enzyme inhibitors, covering the development of new chemical entities, new pharmaceutical formulations with known inhibitors or treatments in combination with other drug families. The development of cholinesterase inhibitors has to face several issues, including the fact that the principal indication for these drugs, Alzheimer's disease, is not currently believed to derivate from a cholinergic deficiency, although most of the drugs clinically used for these disease are cholinesterase inhibitors. Moreover, the adverse effects found when administering cholinesterase inhibitors limit their use in other diseases, such as gastrointestinal diseases, glaucoma, or analgesia.

ACETYL CHOLINESTERASE AND BUTYRYL CHOLINESTERASE INhIBITORY ACTIVITIES OF ZALEYA PENTANDRA.

PubMed

Afzal, Samina; Chaudhry, Bashir Ahmad; Afzal, Khurram; Saeed, Javeria; Akash, Sajd Hamid; Qadir, Muhammad Imran

2017-05-01

The aim of this study was to reveal acetyl cholinesterase (AchE) and butyryl cholinesterase (BchE) inhibitory activities of Zaleya pentandra. The aerial parts of the plant were air, freeze-dried and powdered. The extraction was carried out with methanol at room temperature for 24 h. The extract was concentrated on rotavapor and fractioned by column chromatography. The isolation and purification afforded amorphous solid which was subjected to physical, chemical and spectroscopic techniques i.e., UV, IR, H-NMR, "C-NMR and HREI-MS for the structure elucidation of the isolated compound. The compound was concluded as "Pentandradione" a novel compound. AchE and BchE inhibitory activities were estimated. The result showed that the isolated extract possessed significant activity against butyryl cholinesterase as compared to standard eserine while the extract lacks acetyl cholinesterase inhibitory activity.

THE EFFECT OF IONIZING RADIATION ON ACETYLCHOLINE METABOLISM IN MACACA- RHESUS MONKEYS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demin, N.N.; Korneeva, N.V.; Shaternikov, V.A.

1961-11-01

In macaca-rhesus monkeys the normal content of free acetylcholine in the mucosa of the small intestine was higher, as it was in brain and liver, than bound acetyl choline. The total cholinesterase activity and, particularly, the activity of acetylcholinesterase and non-specific cholinesterase in control monkeys is highest in brain, followed by intestinal mucosa and liver. One to three days after gamma -irradiation of the monkey at a dose of 600 r the amount of free and bound acetylcholine in the mucosa of the small intestine increased, while it decreased in liver. The total cholinesterase activity in the mucosa of themore » small intestine during this period increased, in general because of the increase in the activity of non-specific cholinesterase. In the liver the increase in total cholinesterase activity also occurred because of an increase in non-specific cholinesterase activity, but was less clear-cut and occurred later (the third day after irradiation). In animals irradiated 2 to 3 years before the investigation, an increased concentration of free acetylcholine in brain, liver, and mucosa of the small intestine was noted; but there were no ehanges in bound acetylcholine. The total cholinesterase activity increased in liver as a result of acetyl cholinesterase increase and non-specific enzymes, and in mucosa of the small intestine only as a result of acetylcholinesterase activity. In brain the total cholinesterase activity decreased as a consequence of a decrease in acetylcholinesterase activity. (auth)« less

Integration of active and passive microwave signatures for characterization of soil properties

NASA Astrophysics Data System (ADS)

Laulhe, Sebastien

The reaction between an aminooxy moiety (RONH2) and a carbonyl group of either an aldehyde or a ketone --- known as an oximation reaction --- is a versatile click chemistry coupling that generates a robust oxime ether linkage. The oximation reaction is chemoselective and can be performed under mild conditions in a large variety of solvents, including water. The attractive properties of the aminooxy group and derived oximation reactions, reviewed in Chapter 1, inspired us to use this chemistry as a key feature of our research. Specifically, we prepare functionalized aminooxy compounds so that the oximation chemistry can then serve as a prelude to new synthetic or analytical methods. For example, Chapter 2 presents an improved preparation of O-(diphenylphosphinyl)hydroxylamine (DPPH), an aminooxy-containing reagent, using the classic Schotten-Baumann conditions. We show how DPPH can then be used as a chemoselective nitrogen transfer reagent for a one-pot aldehyde-to-nitrile functional group transformation. Sixteen aldehydes were smoothly transformed to their corresponding nitriles by heating at 85 °C with DPPH in toluene. The reaction can be accomplished in the presence of alcohol, ketone, ester, or amine functionality. In another application, we use functionalized aminooxy reagents to achieve quantitative multiplexed gas chromatography-mass spectrometry (GC-MS) analysis. Specifically, we chemoselectively derivatize carbonyl (aldehyde and ketone) metabolites using the aminooxy-containing reagents. Chapter 3 presents a focused fundamental study of the propensity of oxime ethers to undergo MS-induced fragmentations, such as the McLafferty rearrangement. In particular, we studied structural factors that promoted alpha,beta-fragmentation in oximes of both ketones and aldehydes, as well as the derived silyl ethers of these adducts. We determined that 1) the propensity of the McLafferty rearrangement was greatly enhanced by oxygen at the b-position of silyl oxime ethers, 2) the McLafferty rearrangement is more prominent for E-isomers of oxime and silyl oxime ethers than for the corresponding Z-isomers, and 3) Z-isomers of silyl oxime ethers with CH2 at the b-position generate nitrilium ions to a greater extent than their corresponding E-isomers. Chapter 4 describes the 3-step synthesis of a new class of stable isotope-labeled derivatizing reagents ---- a&barbelow;minooxye&barbelow;thyl p&barbelow;ropionate reagents (AEP) ---- that enable multiplexed GC-MS analysis of small molecule carbonyl compounds. The AEP reagents contain 1) an aminooxy moiety, and 2) a propionate ester moiety that generates a reporter isotope-labeled mass spectral tag (MST) in the form of an ethyl carbenium ion via an ester a-cleavage. The AEP MSTs appear in an m/z zone of minimal interference (ZMI) in the range m/z 32-34. This is a key feature in that unobstructed observation of reporter MSTs in this zone significantly improves simultaneous quantitation of carbonyl analytes from multiple samples without recourse to MS peak deconvolution strategies. Also, and in contrast to known isotope coding reagents for GC-MS, AEP reagents are not affected by the chromatographic isotope effect. The versatility of the technology for carbonyl metabolite profiling and absolute quantification is demonstrated by an analysis of turmeric extract, serving as a representative complex biological sample. A series of analogous methyl ketones were profiled from characteristic MS fragmentations of the AEP-derived oxime ether adducts, and two members, 2-nonanone and 2-undecanone, were quantified using AEP-labeled external standards. Finally, Chapter 5 concludes with additional demonstrations of click chemistry. We used oximation to ligate linker molecules to fluorophores and gold nanoparticles (AuNPs) to generate a fluorescent nano-entity for breast cancer location and diagnosis. Five homologous linkers, each consisting of a thiol-terminated hydrophobic domain coupled to an aminooxy-terminated PEG-based domain, were prerared using a 6-step synthesis in 7-25% overall yield. The aminooxy end subsequently was reacted with an aldehyde-functionalized cypate fluorophore, and the thiol end was used for attachment to gold nanoparticles. Linker attachment to cypate in this manner was superior to previously investigated amide coupling involving linker amines and cypate carboxylic acid. Collectively, the results from these investigations demonstrates a novel strategy that employs functionalized aminooxy substrates and reagents to first exploit the high yielding and selective click coupling with carbonyl substrates to set the stage for secondary synthetic or analytical operations. Approaches developed in this multifaceted study appear to be applicable to a variety of synthetic problems ranging from those of a purely chemical nature to other impacting biological systems.

THE PRODUCTS OF THE CYCLIZING DEHYDRATION OF 1-BETA-PHENYLETHYLCYCLOHEXANOL-1 AND THE SYNTHESIS OF SPIROCYCLOHEXANE-1,1-INDANONE-3.

PubMed

Levitz, M; Perlman, D; Bogert, M T

1939-08-04

(1) Spirocyclohexane-1,1-indanone (VI) has been found among the oxidation products of the hydrocarbon mixture which results when 1-beta-phenylethylcyclohexanol-1 is dehydrated, or when 1-beta-phenylethylcyclohexene is cyclized by aluminum trichloride, and its constitution has been proved by synthesis (2) Its oxime melts at 137-137.8 degrees (corr.). The oxime of m.p. 187.5 degrees , reported by Cook et al. therefore must be derived from some other ketone, perhaps the trans-ketoöctahydrophenanthrene, since we were unable to isolate any oxime of m.p. 177 degrees , the figure which they reported for this compound.

Biological Studies in Childhood Schizophrenia: Plasma and RBC Cholinesterase Activity

ERIC Educational Resources Information Center

Lucas, Alexander R.; And Others

1971-01-01

A comparison of plasma (pseudo) cholinesterase and erythrocyte (true) cholinesterase activity in 16 male childhood schizophrenic patients and 16 male nonpsychotic hospitalized controls revealed no significant differences between the two groups. (Author)

Neuroprotective Role of Novel Triazine Derivatives by Activating Wnt/β Catenin Signaling Pathway in Rodent Models of Alzheimer's Disease.

PubMed

Sinha, Anshuman; Tamboli, Riyaj S; Seth, Brashket; Kanhed, Ashish M; Tiwari, Shashi Kant; Agarwal, Swati; Nair, Saumya; Giridhar, Rajani; Chaturvedi, Rajnish Kumar; Yadav, Mange Ram

2015-08-01

It has been reported in the literature that cholinesterase inhibitors provide protection in Alzheimer's disease (AD). Recent reports have implicated triazine derivatives as cholinesterase inhibitors. These findings led us to investigate anti-cholinestrase property of some novel triazine derivatives synthesized in this laboratory. In vitro cholinesterase inhibition assay was performed using Ellman method. The potent compounds screened out from in vitro assay were further evaluated using scopolamine-induced amnesic mice model. Further, in vitro reactive oxygen species (ROS) scavenging and anti-apoptotic property of the potent compounds were demonstrated against Aβ1-42-induced neurotoxicity in rat hippocampal cells. Their neuroprotective role was assessed using Aβ1-42-induced Alzheimer's-like phenotype in rats. Further, the role of compounds on the activation of the Wnt/β-catenin pathway was studied. The results showed that the chosen compounds are having protective effect in Alzheimer's-like condition; the ex vivo results advocated their anti-cholinestrase and anti-oxidant activities. Treatment with TRZ-15 and TRZ-20 showed neuroprotective ability of the compounds as evidenced from the improved cognitive ability in the animals, and decrease in Aβ1-42 burden and cytochrome c and cleaved caspase-3 levels in the brain. This study also demonstrates positive involvement of the novel triazine derivatives in the Wnt/β-catenin pathway. Immunoblot and immunofluorescence data suggested that ratio of pGSK3/GSK3 and β-catenin got dramatically improved after treatment with TRZ-15 and TRZ-20. TRZ-15 and TRZ-20 showed neuroprotection in scopolamine-induced amnesic mice and Aβ1-42-induced Alzheimer's rat model and also activate the Wnt/β-catenin signaling pathway. These findings conclude that TRZ-15 and TRZ-20 could be a therapeutic approach to treat AD.

Evaluation of chlorpyrifos toxicity through a 28-day study: Cholinesterase activity, oxidative stress responses, parent compound/metabolite levels, and primary DNA damage in blood and brain tissue of adult male Wistar rats.

PubMed

Kopjar, Nevenka; Žunec, Suzana; Mendaš, Gordana; Micek, Vedran; Kašuba, Vilena; Mikolić, Anja; Lovaković, Blanka Tariba; Milić, Mirta; Pavičić, Ivan; Čermak, Ana Marija Marjanović; Pizent, Alica; Lucić Vrdoljak, Ana; Želježić, Davor

2018-01-05

In this 28 day-study, we evaluated the effects of the insecticide chlorpyrifos orally administered to Wistar rats at doses 0.160, 0.015, and 0.010 mg/kg b. w./day. Following treatment, total cholinesterase activity and activities of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were measured. Oxidative stress responses were evaluated using a battery of endpoints to establish lipid peroxidation, changes in total antioxidant capacity, level of reactive oxygen species (ROS), glutathione (GSH) level and activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase. Using HPLC-UV DAD analysis, levels of the parent compound and its main metabolite 3,5,6-trichloro-2-pyridinol in plasma and brain tissue were measured. The genotoxic effect was estimated using alkaline comet assay in leukocytes and brain tissue. The exposure did not result in significant effects on total cholinesterase, AChE and BChE activity in plasma and brain tissue. Lipid peroxidation slightly increased both in plasma and brain tissue. Total antioxidant capacity, ROS and GSH levels were marginally influenced by the exposure. Treatment led to significant increases of GSH-Px activity in blood, SOD activity in erythrocytes and a slight increase of catalase activity in plasma. HPLC-UV DAD analysis revealed the presence of both the parent compound and its main metabolite in the plasma of all of the experimental animals and brain tissue of the animals treated at the two higher doses. All of the tested doses of chlorpyrifos were slightly genotoxic, both to leukocytes and brain tissue. Our results call for further research using other sensitive biomarkers of effect, along with different exposure scenarios. Copyright © 2017 Elsevier B.V. All rights reserved.

21 CFR 520.1447 - Milbemycin oxime, lufenuron, and praziquantel tablets.

Code of Federal Regulations, 2014 CFR

2014-04-01

... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS...) Amount. 0.5 mg milbemycin oxime, 10 mg lufenuron, and 5 mg of praziquantel per kilogram of body weight, once a month. (ii) Indications for use. For the prevention of heartworm disease caused by Dirofilaria...

21 CFR 520.1447 - Milbemycin oxime, lufenuron, and praziquantel tablets.

Code of Federal Regulations, 2012 CFR

2012-04-01

... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS...) Amount. 0.5 mg milbemycin oxime, 10 mg lufenuron, and 5 mg of praziquantel per kilogram of body weight, once a month. (ii) Indications for use. For the prevention of heartworm disease caused by Dirofilaria...

21 CFR 520.1447 - Milbemycin oxime, lufenuron, and praziquantel tablets.

Code of Federal Regulations, 2013 CFR

2013-04-01

... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS...) Amount. 0.5 mg milbemycin oxime, 10 mg lufenuron, and 5 mg of praziquantel per kilogram of body weight, once a month. (ii) Indications for use. For the prevention of heartworm disease caused by Dirofilaria...

Phenanthridine synthesis through iron-catalyzed intramolecular N-arylation of O-acetyl oxime.

PubMed

Deb, Indubhusan; Yoshikai, Naohiko

2013-08-16

O-Acetyl oximes derived from 2'-arylacetophenones undergo N-O bond cleavage/intramolecular N-arylation in the presence of a catalytic amount of iron(III) acetylacetonate in acetic acid. In combination with the conventional cross-coupling or directed C-H arylation, the reaction offers a convenient route to substituted phenanthridines.

Synthesis, structural characterization and dielectric behavior of new oxime-cyclotriphosphazene derivatives

NASA Astrophysics Data System (ADS)

Koran, Kenan; Özen, Furkan; Biryan, Fatih; Görgülü, Ahmet Orhan

2016-02-01

The cyclotriphosphazene compound (2) bearing formyl groups as side groups was obtained from the reaction of 2,2-Dichloro-4,4,6,6-bis[spiro(2‧,2″-dioxy-1‧,1″-biphenylyl)]cyclotriphosphazene (1) with 4-hydroxy-3-methoxybenzaldehyde in the presence K2CO3 in tetrahydrofuran. Oxime-cyclotriphosphazene compound (3) was synthesized from the reaction of compound 2 with hydroxylamine hydrochloride in pyridine. The synthesized oxime-phosphazene compound (3) was reacted with alkyl and acyl halides. As a results, the cyclotriphosphazene compounds (1-10) bearing oxime ether and ester as side groups were obtained. The chemical structures of these compounds (1-10) were determined by elemental analysis, FT-IR, 1H, 13C and 31P NMR spectroscopic methods. Dielectric constant, dielectric loss factors and conductivity properties of cyclotriphosphazene compounds were measured over the frequency range from 100 Hz to 2 kHz at 25 °C and compared with each other. It is found that ester substituted cyclotriphosphazenes have higher dielectric constant. Our study suggests that these phosphazenes promising candidate materials in multifunctional optoelectronic devices.

Oxime amides as a novel zinc binding group in histone deacetylase inhibitors: synthesis, biological activity, and computational evaluation.

PubMed

Botta, Cinzia B; Cabri, Walter; Cini, Elena; De Cesare, Lucia; Fattorusso, Caterina; Giannini, Giuseppe; Persico, Marco; Petrella, Antonello; Rondinelli, Francesca; Rodriquez, Manuela; Russo, Adele; Taddei, Maurizio

2011-04-14

Several oxime containing molecules, characterized by a SAHA-like structure, were explored to select a potentially new biasing binding element for the zinc in HDAC catalytic site. All compounds were evaluated for their in vitro inhibitory activity against the 11 human HDACs isoforms. After identification of a "hit" molecule, a programmed variation at the cap group and at the linker was carried out in order to increase HDAC inhibition and/or paralogue selectivity. Some of the new derivatives showed increased activity against a number of HDAC isoforms, even if their overall activity range is still far from the inhibition values reported for SAHA. Moreover, different from what was reported for their hydroxamic acid analogues the new α-oxime amide derivatives do not select between class I and class II HDACs; rather they target specific isoforms in each class. These somehow contradictory results were finally rationalized by a computational assisted SAR, which gave us the chance to understand how the oxime derivatives interact with the catalytic site and justify the observed activity profile.

OHOLO Conference (36th): Multidisciplinary Approaches to Cholinesterase Functions Held in Eilat, Israel on April 6 - 10, 1992.

DTIC Science & Technology

1992-04-10

Acetylcholinesterase in Mosquitoes. Short oral presentation A23.- Roshchina, V.V. - Plant Cholinesterases. A24.- Seidman Shlomo, Revital Ben-Aziz Aloya, Yael ...Hermona Soreq - Differential Transcriptional Control of Cholinesterase Genes in Developing Megakaryocytes. Short oral presentation B13.- Loewenstein Yael ...Against Organophos- phate Poisoning. B20.- Richter ED., I. Orun, J. Ronen , WQ Lu, Y. Yodfat, F. Grauer, J. Marzouk, M. Gordon - Cholinesterase Revisited

CHOLINESTERASE IN DENERVATED END PLATES AND MUSCLE FIBRES

PubMed Central

Brzin, Miro; Majcen-Tkačev, Živa

1963-01-01

Parallel studies were made of cholinesterase activities and localizations in denervated rat and rabbit gastrocnemius muscle. Koelle's histochemical reaction was used for demonstrating the localization of cholinesterases. Enzyme activities in whole sliced muscle were measured by electrometric titration. The Cartesian ampulla-diver technique was used for cholinesterase activity determinations in end plate regions or in small pieces of the muscle fibre itself. No changes in the activity of cholinesterases (ChE) were found in the whole denervated muscle which would account for its chemical supersensitivity. The ChE distribution pattern was changed so that the end plate region became less active in the denervated muscle than in the normal one. The decrease in ChE activity in the end plates seems to be largely compensated for by an increase of this enzyme elsewhere in the muscle. A possible connection between the spatial spread of cholinesterase activity and the enlargement of the acetylcholine-sensitive surface is discussed. PMID:14086761

Discontinuation, Efficacy, and Safety of Cholinesterase Inhibitors for Alzheimer’s Disease: a Meta-Analysis and Meta-Regression of 43 Randomized Clinical Trials Enrolling 16 106 Patients

PubMed Central

Blanco-Silvente, Lídia; Saez, Marc; Barceló, Maria Antònia; Garre-Olmo, Josep; Vilalta-Franch, Joan; Capellà, Dolors

2017-01-01

Abstract Background: We investigated the effect of cholinesterase inhibitors on all-cause discontinuation, efficacy and safety, and the effects of study design-, intervention-, and patient-related covariates on the risk-benefit of cholinesterase inhibitors for Alzheimer’s disease. Methods: A systematic review and meta-analysis of randomized placebo-controlled clinical trials comparing cholinesterase inhibitors and placebo was performed. The effect of covariates on study outcomes was analysed by means of meta-regression using a Bayesian framework. Results: Forty-three randomized placebo-controlled clinical trials involving 16106 patients were included. All-cause discontinuation was higher with cholinesterase inhibitors (OR = 1.66), as was discontinuation due to adverse events (OR=1.75). Cholinesterase inhibitors improved cognitive function (standardized mean difference = 0.38), global symptomatology (standardized mean difference=0.28) and functional capacity (standardized mean difference=0.16) but not neuropsychiatric symptoms. Rivastigmine was associated with a poorer outcome on all-cause discontinuation (Diff OR = 1.66) and donepezil with a higher efficacy on global change (Diff standardized mean difference = 0.41). The proportion of patients with serious adverse events decreased with age (Diff OR = -0.09). Mortality was lower with cholinesterase inhibitors than with placebo (OR = 0.65). Conclusion: While cholinesterase inhibitors show a poor risk-benefit relationship as indicated by mild symptom improvement and a higher than placebo all-cause discontinuation, a reduction of mortality was suggested. Intervention- and patient-related factors modify the effect of cholinesterase inhibitors in patients with Alzheimer’s disease. PMID:28201726

Discontinuation, Efficacy, and Safety of Cholinesterase Inhibitors for Alzheimer's Disease: a Meta-Analysis and Meta-Regression of 43 Randomized Clinical Trials Enrolling 16 106 Patients.

PubMed

Blanco-Silvente, Lídia; Castells, Xavier; Saez, Marc; Barceló, Maria Antònia; Garre-Olmo, Josep; Vilalta-Franch, Joan; Capellà, Dolors

2017-07-01

We investigated the effect of cholinesterase inhibitors on all-cause discontinuation, efficacy and safety, and the effects of study design-, intervention-, and patient-related covariates on the risk-benefit of cholinesterase inhibitors for Alzheimer's disease. A systematic review and meta-analysis of randomized placebo-controlled clinical trials comparing cholinesterase inhibitors and placebo was performed. The effect of covariates on study outcomes was analysed by means of meta-regression using a Bayesian framework. Forty-three randomized placebo-controlled clinical trials involving 16106 patients were included. All-cause discontinuation was higher with cholinesterase inhibitors (OR = 1.66), as was discontinuation due to adverse events (OR=1.75). Cholinesterase inhibitors improved cognitive function (standardized mean difference = 0.38), global symptomatology (standardized mean difference=0.28) and functional capacity (standardized mean difference=0.16) but not neuropsychiatric symptoms. Rivastigmine was associated with a poorer outcome on all-cause discontinuation (Diff OR = 1.66) and donepezil with a higher efficacy on global change (Diff standardized mean difference = 0.41). The proportion of patients with serious adverse events decreased with age (Diff OR = -0.09). Mortality was lower with cholinesterase inhibitors than with placebo (OR = 0.65). While cholinesterase inhibitors show a poor risk-benefit relationship as indicated by mild symptom improvement and a higher than placebo all-cause discontinuation, a reduction of mortality was suggested. Intervention- and patient-related factors modify the effect of cholinesterase inhibitors in patients with Alzheimer's disease. © The Author 2017. Published by Oxford University Press on behalf of CINP.

Genetic variants of human serum cholinesterase influence metabolism of the muscle relaxant succinylcholine.

PubMed

Lockridge, O

1990-01-01

People with genetic variants of cholinesterase respond abnormally to succinylcholine, experiencing substantial prolongation of muscle paralysis with apnea rather than the usual 2-6 min. The structure of usual cholinesterase has been determined including the complete amino acid and nucleotide sequence. This has allowed identification of altered amino acids and nucleotides. The variant most frequently found in patients who respond abnormally to succinylcholine is atypical cholinesterase, which occurs in homozygous form in 1 out of 3500 Caucasians. Atypical cholinesterase has a single substitution at nucleotide 209 which changes aspartic acid 70 to glycine. This suggests that Asp 70 is part of the anionic site, and that the absence of this negatively charged amino acid explains the reduced affinity of atypical cholinesterase for positively charged substrates and inhibitors. The clinical consequence of reduced affinity for succinylcholine is that none of the succinylcholine is hydrolyzed in blood and a large overdose reaches the nerve-muscle junction where it causes prolonged muscle paralysis. Silent cholinesterase has a frame shift mutation at glycine 117 which prematurely terminates protein synthesis and yields no active enzyme. The K variant, named in honor of W. Kalow, has threonine in place of alanine 539. The K variant is associated with 33% lower activity. All variants arise from a single locus as there is only one gene for human cholinesterase (EC 3.1.1.8). Comparison of amino acid sequences of esterases and proteases shows that cholinesterase belongs to a new family of serine esterases which is different from the serine proteases.

Integrated Lateral Flow Test Strip with Electrochemical Sensor for Quantification of Phosphorylated Cholinesterase: Biomarker of Exposure to Organophosphorus Agents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, Dan; Wang, Jun; Wang, Limin

An integrated lateral flow test strip with electrochemical sensor (LFTSES) device with rapid, selective and sensitive response for quantification of exposure to organophosphorus (OP) pesticides and nerve agents has been developed. The principle of this approach is based on parallel measurements of post-exposure and baseline acetylcholinesterase (AChE) enzyme activity, where reactivation of the phosphorylated AChE is exploited to enable measurement of total amount of AChE (including inhibited and active) which is used as a baseline for calculation of AChE inhibition. Quantitative measurement of phosphorylated adduct (OP-AChE) was realized by subtracting the active AChE from the total amount of AChE. Themore » proposed LFTSES device integrates immunochromatographic test strip technology with electrochemical measurement using a disposable screen printed electrode which is located under the test zone. It shows linear response between AChE enzyme activity and enzyme concentration from 0.05 to 10 nM, with detection limit of 0.02 nM. Based on this reactivation approach, the LFTSES device has been successfully applied for in vitro red blood cells inhibition studies using chlorpyrifos oxon as a model OP agent. This approach not only eliminates the difficulty in screening of low-dose OP exposure because of individual variation of normal AChE values, but also avoids the problem in overlapping substrate specificity with cholinesterases and avoids potential interference from other electroactive species in biological samples. It is baseline free and thus provides a rapid, sensitive, selective and inexpensive tool for in-field and point-of-care assessment of exposures to OP pesticides and nerve agents.« less

Effects of Ionizing Radiation on Arylesterase and Cholinesterase.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Augustinsson, Klas-Bertil; Jonsson, Gunnel; Sparrman, Berndt

1961-01-01

The effects of Co 60 gamma radiation on arylesterase and cholinesterase of human blood plasma were compared using solid preparations of purified enzymes containing various amounts of water. In the case of cholinesterase a water content of 12% exerted maximum protection against irradiation. Such a protection by water was not observed with arylesterase. Finally, in aqueous solutions cholinesterase was more resistant to irradiation by gamma rays than was arylesterase when irradiation was performed in an atmosphere of nitrogen.

21 CFR 520.1445 - Milbemycin oxime and praziquantel.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Section 520.1445 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... orally, once a month, a minimum dosage of 0.23 mg per pound (mg/lb) of body weight (0.5 mg per kilogram (mg/kg)) milbemycin oxime and 2.28 mg/lb of body weight (5 mg/kg) praziquantel. (ii) Indications for...

21 CFR 520.1445 - Milbemycin oxime and praziquantel.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Section 520.1445 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... orally, once a month, a minimum dosage of 0.23 mg per pound (mg/lb) of body weight (0.5 mg per kilogram (mg/kg)) milbemycin oxime and 2.28 mg/lb of body weight (5 mg/kg) praziquantel. (ii) Indications for...

Construction of Benzene Rings by Copper-Catalyzed Cycloaddition Reactions of Oximes and Maleimides: An Access to Fused Phthalimides.

PubMed

Yang, Jie; Zhao, Bo; Xi, Yue; Sun, Si; Yang, Zhen; Ye, Ying; Jiang, Kun; Wei, Ye

2018-02-16

A useful Cu-catalyzed cycloaddition protocol for the construction of benzene rings has been achieved. The reactions, utilizing readily available oximes and maleimides as starting materials, proceed under mild reaction conditions to generate a series of structurally interesting fused-phthalimides that are difficult to be prepared by conventional methods.

Association of genetic polymorphisms of telomere binding proteins with cholinesterase activity in omethoate-exposed workers.

PubMed

Ding, Mingcui; Yang, Yongli; Duan, Xiaoran; Wang, Sihua; Feng, Xiaolei; Wang, Tuanwei; Wang, Pengpeng; Liu, Suxiang; Li, Lei; Liu, Junling; Tang, Lixia; Niu, Xinhua; Zhang, Yuhong; Li, Guoyu; Yao, Wu; Cui, Liuxin; Wang, Wei

2018-06-18

Omethoate, an organophosphorous pesticide, can cause a variety of health effects, especially the decrease of cholinesterase activity. The aim of this study is to explore the association of genetic polymorphisms of telomere binding proteins with cholinesterase activity in omethoate-exposed population. Cholinesterase activities in whole blood, red blood cell and plasma were detected using acetylthiocholine and dithio-bis-(nitrobenzoic acid) method; Genetic Genotyping of POT1 rs1034794, POT1 rs10250202, TERF1 rs3863242 and TERT rs2736098 were performed with PCR-RFLP. The cholinesterase activities of whole blood, red blood cells and plasma in exposure group are significantly lower than that of the control group (P < 0.001). Multivariate analysis indicates that exposure group (b = - 1.016, P < 0.001), agender (b = 0.365, P < 0.001), drinking (b = 0.271, P = 0.004) and TERF1rs3863242 (b = - 0.368, P = 0.016) had an impact on cholinesterase activities. The results suggest that individual carrying AG+GG genotypes in TERF1 gene rs3863242 polymorphism were susceptible to damage in cholinesterase induced by omethoate. Copyright © 2018 Elsevier Inc. All rights reserved.

NEURO-GUMORALE SUBSTANCES OF DOG BLOOD DURING ACUTE RADIATION SICKNESS. I. CHANGES IN BLOOD ACETYLCHOLINE AND CHOLINESTERASE SYSTEM (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuznetzova, N.E.

1963-01-01

Experiments carried out on 13 male dogs, 2 to 5 years old and weighing 10 to 20 kg, showed that in the initial stages of chroric radiation sickness the blood content of acetylcholine increased and the cholinesterase decreased. Moreove r, the increase in the acetylcholine level during the first 3 to 4 hrs proceeded at a greater rate than the cholinesterase decrease. Shifts in the enzyme system were more pronounced in dogs with greater resistance. However, during the recovery period acetylcholine and cholinesterase restoration took place at earlier periods in dogs with higher resistance. Not only was the cholinesterase activitymore » restored, but it increased to 1.5 to 2 times the initial level. The level of acetylcholine and cholinesterase was not restored in the blood of dogs during terminal periods. In dogs exposed to subacute doses, 300 r, enzyme normalization took place 29 to 41 days following exposure. Correlation of data on enzyme changes in single and chronic exposures indicated identical trends It was postulated that acetylcholine -cholinesterase participate in compensating reactions of organisms during radiation sickness. (R.V.J.)« less

INFLUENCE OF X-IRRADIATION UPON ACTIVITY OF CHOLINESTERASE IN LIVER AND SERUM. PARTS I-III

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ioroi, M.

1960-01-01

The activity of cholinesterase in the liver, studied in rabbits and rats, was more inhibited when the liver was irradiated by a single x-ray dose than by fractionated doses. With l00, 300, and 600 r of whole-body irradiation, the activity of cholinesterase in the liver was stimulated; meanwhile in serum it was inhibited. With l000 and 2000 r, the activities in both serum and liver were severely inhibited. WWhen the diencephalon and spinal cord were irradiated with fractionated doses (l50 r twice a week), the activity of cholinesterase in both liver and serum showed no appreciable change. When whole-body irradiationmore » (l00 r per day) was given, the activity of cholinesterase in both liver and serum was somewhat stimulated. After liver irradiation (200 r per day; total dose 4000 r) the activity of cholinesterase in both liver and serum was inhibited. In patients who showed high activity of cholinesterase in serum before x-ray therapy, the activity was slightly inhibited after x-ray treatment, and patients who showed low activity before therapy were slightly stimulated after x irradiation. (Abstr. Japan Med., l: No. 13, l96l)« less

Transition Metal Free Multicomponent approach to Stereo-enriched Cyclopentyl-isoxazoles via C-C Bond Cleavage.

PubMed

Kaliappan, Krishna Pillai; Subramanian, Parthasarathi

2018-06-19

An efficient multicomponent reaction leading to the synthesis of stereo-enriched cyclopentyl-isoxazoles from camphor derived α-oxime, alkynes and MeOH is reported. Our method involves a series of cascade transformations such as in situ generation of catalyst I(III) which catalyzes the addition MeOH into a sterically hindered ketone, oxime oxidation and α-hydroxyiminium ion rearrangement to generate in situ nitrile oxide which upon [3+2]-cycloaddition reaction with alkynes delivers regioselective products. The reaction is very selective to syn-oxime. This multicomponent approach has also been extended for the synthesis of a novel glycoconjugate, camphoric ester-isoxazole C-galactoside. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Coumarin-Based Oxime Esters: Photobleachable and Versatile Unimolecular Initiators for Acrylate and Thiol-Based Click Photopolymerization under Visible Light-Emitting Diode Light Irradiation.

PubMed

Li, Zhiquan; Zou, Xiucheng; Zhu, Guigang; Liu, Xiaoya; Liu, Ren

2018-05-09

Developing efficient unimolecular visible light-emitting diode (LED) light photoinitiators (PIs) with photobleaching capability, which are essential for various biomedical applications and photopolymerization of thick materials, remains a great challenge. Herein, we demonstrate the synthesis of a series of novel PIs, containing coumarin moieties as chromophores and oxime ester groups as initiation functionalities and explore their structure-activity relationship. The investigated oxime esters can effectively induce acrylates and thiol-based click photopolymerization under 450 nm visible LED light irradiation. The initiator O-3 exhibited excellent photobleaching capability and enabled photopolymerization of thick materials (∼4.8 mm). The efficient unimolecular photobleachable initiators show great potential in dental materials and 3D printings.

Micellar catalyzed degradation of fenitrothion, an organophosphorus pesticide, in solution and soils.

PubMed

Balakrishnan, Vimal K; Buncel, Erwin; Vanloon, Gary W

2005-08-01

We report on a study of the decomposition of fenitrothion (an organophosphorus pesticide that is a persistent contaminant in soils and groundwater) as catalyzed by cetyltrimethylammonium (CTA+) micelles. The CTA micelles were associated with two types of counterions: (1) inert counterions (e.g. CTABr) and (2) reactive counterions (e.g. CTAOH). The reactive counterion surfactants used were hydroxide anion (HO-) as a normal nucleophile and hydroperoxide anion (HOO-) and the anion of pyruvaldehyde oxime (MINA-) as two alpha-nucleophiles. The reactivity order followed: CTABr < CTAOH < CTAMINA < CTAOOH. Treatment of the rate data using the Pseudo-Phase Ion Exchange (PPIE) model of micellar catalysis showed the ratio k2M/k2w to be less than unity for all the surfactants employed. Rather than arising from a "true catalysis", we attributed the observed rate enhancements to a "concentration effect", where both pesticide and nucleophile were incorporated into the small micellar phase volume. Furthermore, the CTAOOH/CTAOH pair gave an alpha-effect of 57, showing that the alpha-effect can play an important role in micellar systems. We further investigated the effectiveness of reactive counterion surfactants in decontaminating selected environmental solids that were spiked with 27 ppb fenitrothion. The solids were as follows: the clay mineral montmorillonite and SO-1 and S0-2 soils (obtained from the Canadian Certified Reference Materials Project). The reactive counterion surfactant solutions significantly enhanced the rate of fenitrothion degradation in the spiked solids over that obtained when the spiked solid was placed in contact with either 0.02 M KOH or water. The rate enhancements followed the order CTAOOH > CTAMINA approximately CTAOH > KOH > water. We conclude that reactive counterion surfactants, especially with alpha-nucleophiles, hold great potential in terms of remediating soils contaminated by toxic organophosphorus esters.

Molecular modeling and biological evaluation of 2-N,N-dimethylaminecyclohexyl 1-N‧,N‧-dimethylcarbamate isomers and their methylsulfate salts as cholinesterases inhibitors

NASA Astrophysics Data System (ADS)

Bocca, Cleverson C.; Rittner, Roberto; Höehr, Nelci F.; Pinheiro, Glaucia M. S.; Abiko, Layara A.; Basso, Ernani A.

2010-11-01

This work presents a detailed theoretical and experimental study on the inhibitory properties of 2- N,N-dimethylaminecyclohexyl 1- N',N'-dimethylcarbamate isomers and their methylsulfate salts against the cholinesterases enzymes. The in vitro inhibition test performed by the Ellman's method showed that the salt form compounds were more active than the neutral ones in cholinesterases inhibition. The trans salt showed good selectivity towards the inhibition of erythrocyte cholinesterase with a maximum limit around 90% and 55% for the plasma cholinesterase inhibition. Molecular modeling, docking and experimental results performed in this study showed to be important initial steps toward the development of a novel pharmaceuticals in the fight against Alzheimer's disease.

DIFFERENTIAL PROFILES OF CHOLINESTERASE INHIBITION AND NEUROBEHAVIORAL EFFECTS IN RATS EXPOSED TO FENSMIPHOS OR PROFENOPHOS.

EPA Science Inventory

This manuscript examines the relationship between cholinesterase inhibition and behavioral effects produced by two pesticides, fenamiphos and profenophos. Both pesticides greatly inhibit blood cholinesterase but the brain is relatively spared up to lethal doses. Despite the sim...

Whole Blood Cholinesterase Activity in 20 Species of Wild Birds.

PubMed

Horowitz, Igal H; Yanco, Esty G; Landau, Shmulik; Nadler-Valency, Rona; Anglister, Nili; Bueller-Rosenzweig, Ariela; Apelbom-Halbersberg, Tal; Cuneah, Olga; Hanji, Vera; Bellaiche, Michel

2016-06-01

Clinical signs of organophosphate and carbamate intoxication in wild birds can be mistaken for those of other diseases, thus potentially delaying diagnosis and implementation of life-saving treatment. The objective of this study was to determine the reference interval for blood cholinesterase activity in 20 different wild avian species from 7 different orders, thereby compiling a reference database for wildlife veterinarians. Blood was collected from birds not suspected of having organophosphate or carbamate toxicosis, and the modified Michel method, which determines the change in blood pH that directly correlates with cholinesterase activity, was used to measure blood cholinesterase levels. Results of change in blood pH values ranged from 0.11 for the white-tailed eagle ( Haliaeetus albicilla ) to 0.90 for the honey buzzard ( Pernis apivorus ). The results showed that even within the same family, interspecies differences in normal cholinesterase blood activity were not uncommon. The findings emphasized the importance of determining reference intervals for avian blood cholinesterase activity at the species level.

Cholinesterases as biomarkers for parasympathetic dysfunction and inflammation-related disease.

PubMed

Shenhar-Tsarfaty, Shani; Berliner, Shlomo; Bornstein, Natan M; Soreq, Hermona

2014-07-01

Accumulating evidence suggests parasympathetic dysfunction and elevated inflammation as underlying processes in multiple peripheral and neurological diseases. Acetylcholine, the main parasympathetic neurotransmitter and inflammation regulator, is hydrolyzed by the two closely homologous enzymes, acetylcholinesterase and butyrylcholinesterase (AChE and BChE, respectively), which are also expressed in the serum. Here, we consider the potential value of both enzymes as possible biomarkers in diseases associated with parasympathetic malfunctioning. We cover the modulations of cholinesterase activities in inflammation-related events as well as by cholinesterase-targeted microRNAs. We further discuss epigenetic control over cholinesterase gene expression and the impact of single-nucleotide polymorphisms on the corresponding physiological and pathological processes. In particular, we focus on measurements of circulation cholinesterases as a readily quantifiable readout for changes in the sympathetic/parasympathetic balance and the implications of changes in this readout in health and disease. Taken together, this cumulative know-how calls for expanding the use of cholinesterase activity measurements for both basic research and as a clinical assessment tool.

Does diazinon-sprayed market melon alter cholinesterase activity in healthy consumers? A randomized control trial.

PubMed

Nematy, M; Tashakori-Behesti, A; Megarbane, B; Bakaiyan, M; Habibi, M; Afashari, R

2016-06-01

Food contributes in measurable body burden of the widely used organophosphate pesticides. We designed a randomized controlled open label trial in Mashhad University Hospital in Iran, to study the possible alterations in cholinesterase activity resulting from consuming market melon known to be exposed to diazinon. Fifty-three young healthy volunteers were recruited. Participants were randomized to consume 250 g per day of organic (N = 22) vs. market melon (N = 31) during fifteen days. The primary outcome was the variation of red blood-cell (RBC) cholinesterase activity between day 15 (after) and day 0 (prior the intervention). The secondary outcome was a variation of the plasma cholinesterase activity between both dates. Baseline RBC [5.21 ± 0.93 vs. 5.53 ± 0.99 IU/mL, mean ± SD] and plasma cholinesterase activities [54.0 ± 8.1 vs. 57.4 ± 8.6%] did not significantly differ between organic and market melon-exposed participants, respectively. RBC [5.86 ± 1.27 vs. 5.11 ± 1.2 IU/mL] and plasma cholinesterase activities [58.7 ± 10.0 vs. 50.5 ± 13.0%] significantly increased in organic melon-exposed vs. market melon-exposed participants (p = 0.002 and p = 0.001, respectively). RBC and plasma cholinesterase activities significantly improved after eating organic instead of market melon during fifteen days. However, the consequences on the health of the observed cholinesterase alterations attributed to diazinon dietary intake remain to be determined.

Evaluation of Candidate Genes for cholinesterase Activity in Farmworkers Exposed to organophosphorous Pesticides-Association of SNPs in BCHE

EPA Science Inventory

Background: Organophosphate pesticides act as cholinesterase inhibitors, and as such may give rise to potential neurological effects. Cholinesterase activity is a useful, indirect measurement of pesticide exposure, especially in high-risk individuals such as farmworkers. To und...

40 CFR 721.6660 - Polymer of alkanepolyol and poly-alkyl-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymer of alkanepolyol and poly-alkyl... Polymer of alkanepolyol and poly-alkyl-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime-blocked... substance identified generically as a polymer of alkane-polyol and polyalkylpolyisocyanatocarbomonocy- cle...

40 CFR 721.6660 - Polymer of alkanepolyol and poly-alkyl-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polymer of alkanepolyol and poly-alkyl... Polymer of alkanepolyol and poly-alkyl-poly-iso-cyan-ato-car-bo-mo-no-cycle, acetone oxime-blocked... substance identified generically as a polymer of alkane-polyol and polyalkylpolyisocyanatocarbomonocy- cle...

Iron-Catalyzed Intramolecular C(sp(2))-N Cyclization of 1-(N-Arylpyrrol-2-yl)ethanone O-Acetyl Oximes toward Pyrrolo[1,2-a]quinoxaline Derivatives.

PubMed

Zhang, Zhiguo; Li, Junlong; Zhang, Guisheng; Ma, Nana; Liu, Qingfeng; Liu, Tongxin

2015-07-02

An efficient and convenient iron-catalyzed protocol has been developed for the synthesis of substituted pyrrolo[1,2-a]quinoxalines from 1-(N-arylpyrrol-2-yl)ethanone O-acetyl oximes through N-O bond cleavage and intramolecular directed C-H arylation reactions in acetic acid.

Eco-friendly synthesis, physicochemical studies, biological assay and molecular docking of steroidal oxime-ethers

PubMed Central

Alam, Mahboob; Lee, Dong-Ung

2015-01-01

The aim of this study was to report the synthesis of biologically active compounds; 7-(2′-aminoethoxyimino)-cholest-5-ene (4), a steroidal oxime-ether and its derivatives (5, 6) via a facile microwave assisted solvent free reaction methodology. This new synthetic, eco-friendly, sustainable protocol resulted in a remarkable improvement in the synthetic efficiency (85-93 % yield) and high purity using basic alumina. The synthesized compounds were screened for their antibacterial against six bacterial strains by disc diffusion method and antioxidant potential by DPPH assay. The binding capabilities of a compound 6 exhibiting good antibacterial potential were assessed on the basis of molecular docking studies and four types of three-dimensional molecular field descriptors. Moreover the structure-antimicrobial activity relationships were studied using some physicochemical and quantum-chemical parameters with GAMESS interface as well as WebMO Job Manager by using the basic level of theory. Hence, this synthetic approach is believed to provide a better scope for the synthesis of steroidal oxime-ether analogues and will be a more practical alternative to the presently existing procedures. Moreover, detailed in silico docking studies suggested the plausible mechanism of steroidal oxime-ethers as effective antimicrobial agents. PMID:27330525

Insights into the mechanism and catalysis of oxime coupling chemistry at physiological pH.

PubMed

Wang, Shujiang; Gurav, Deepanjali; Oommen, Oommen P; Varghese, Oommen P

2015-04-07

The dynamic covalent-coupling reaction involving α-effect nucleophiles has revolutionized bioconjugation approaches, due to its ease and high efficiency. Key to its success is the discovery of aniline as a nucleophilic catalyst, which made this reaction feasible under physiological conditions. Aniline however, is not so effective for keto substrates. Here, we investigate the mechanism of aniline activation in the oxime reaction with aldehyde and keto substrates. We also present carboxylates as activating agents that can promote the oxime reaction with both aldehyde and keto substrates at physiological pH. This rate enhancement circumvents the influence of α-effect by forming H-bonds with the rate-limiting intermediate, which drives the reaction to completion. The combination of aniline and carboxylates had a synergistic effect, resulting in a ∼14-31-fold increase in reaction rate at pD 7.4 with keto substrates. The biocompatibility and efficiency of carboxylate as an activating agent is demonstrated by performing cell-surface oxime labeling at physiological pH using acetate, which showed promising results that were comparable with aniline. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Iminosugars as a new class of cholinesterase inhibitors.

PubMed

Decroocq, Camille; Stauffert, Fabien; Pamlard, Olivier; Oulaïdi, Farah; Gallienne, Estelle; Martin, Olivier R; Guillou, Catherine; Compain, Philippe

2015-02-15

To further extend the scope of iminosugar biological activity, a systematic structure-activity relationship investigation has been performed by synthesizing and evaluating as cholinesterase inhibitors a library of twenty-three iminoalditols with different substitutions and stereochemistry patterns. These compounds have been evaluated in vitro for the inhibition of cholinesterases (different sources of acetylcholinesterase and butyrylcholinesterase). Some compounds have IC50 values in the micromolar range and display significant inhibition selectivity for butyrylcholinesterase over acetylcholinesterase. These are the first examples of iminosugar-based inhibitors of cholinesterases. Copyright © 2015 Elsevier Ltd. All rights reserved.

Natural Detoxification Capacity to Inactivate Nerve Agents Sarin and VX in the Rat Blood.

PubMed

Bajgar, Jiří; Cabal, Jiří; Kassa, Jiří; Pavlík, Michal

2015-01-01

The method of continual determination of the rat blood cholinesterase activity was developed to study the changes of the blood cholinesterases following different intervetions. The aim of this study is registration of cholinesterase activity in the rat blood and its changes to demonstrate detoxification capacity of rats to inactivate sarin or VX in vivo. The groups of female rats were premedicated (ketamine and xylazine) and cannulated to a. femoralis. Continual blood sampling (0.02 ml/min) and monitoring of the circulating blood cholinesterase activity were performed. Normal activity was monitored 1-2 min and then the nerve agent was administered i.m. (2×LD50). Using different time intervals of the leg compression and relaxation following the agent injection, cholinesterase activity was monitored and according to the inhibition obtained, detoxification capacity was assessed. Administration of sarin to the leg, then 1 and 5 min compression and 20 min later relaxation showed that further inhibition in the blood was not observed. On the other hand, VX was able to inhibit blood cholinesterases after this intervention. The results demonstrated that sarin can be naturally detoxified on the contrary to VX. Described method can be used as model for other studies dealing with changes of cholinesterases in the blood following different factors.

Development of acetophenone ligands as potential neuroimaging agents for cholinesterases.

PubMed

Jollymore-Hughes, Courtney T; Pottie, Ian R; Martin, Earl; Rosenberry, Terrone L; Darvesh, Sultan

2016-11-01

Association of cholinesterase with β-amyloid plaques and tau neurofibrillary tangles in Alzheimer's disease offers an opportunity to detect disease pathology during life. Achieving this requires development of radiolabelled cholinesterase ligands with high enzyme affinity. Various fluorinated acetophenone derivatives bind to acetylcholinesterase with high affinity, including 2,2,2-trifluoro-1-(3-dimethylaminophenyl)ethanone (1) and 1-(3-tert-butylphenyl)-2,2,2-trifluoroethanone (2). Such compounds also offer potential for incorporation of radioactive fluorine ( 18 F) for Positron Emission Tomography (PET) imaging of cholinesterases in association with Alzheimer's disease pathology in the living brain. Here we describe the synthesis of two meta-substituted chlorodifluoroacetophenones using a Weinreb amide strategy and their rapid conversion to the corresponding trifluoro derivatives through nucleophilic substitution by fluoride ion, in a reaction amenable to incorporating 18 F for PET imaging. In vitro kinetic analysis indicates tight binding of the trifluoro derivatives to cholinesterases. Compound 1 has a K i value of 7nM for acetylcholinesterase and 1300nM for butyrylcholinesterase while for compound 2 these values are 0.4nM and 26nM, respectively. Tight binding of these compounds to cholinesterase encourages their development for PET imaging detection of cholinesterase associated with Alzheimer's disease pathology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Potential association of reduced cholinesterase activity with Trypanosoma evansi pathogenesis in buffaloes.

PubMed

Singh, Shanker K; Singh, Vivek K; Yadav, Brajesh K; Nakade, Udayraj P; Kumari, Priyambada; Srivastava, Mukesh K; Sharma, Abhishek; Choudhary, Soumen; Swain, Dilip; Garg, Satish K

2016-07-30

The present study aimed to investigate the association of cholinesterase activity with trypanosomosis in buffaloes. Thirty-three clinical cases of trypanosomosis in water buffaloes, found positive for trypomastigotes of T. evansi on blood smear examination, were divided into two groups based on clinical manifestations. Twenty diseased buffaloes revealing only common clinical signs were allocated to Group I, while the remaining 13 buffaloes showing common clinical manifestations along with neurological disturbances were allocated to Group II. Twelve clinically healthy buffaloes, free from any haemoprotozoa infection, were kept as healthy control (Group III). Blood samples were collected from buffaloes of all three groups to determine serum cholinesterase activity. Compared to buffaloes of healthy control group, cholinesterase activity in T. evansi-infected buffaloes of Group I and II was significantly (P<0.001) lower. However, no significant difference was observed in cholinesterase activity between the T. evansi-infected buffaloes exhibiting neurological disorders and no neurological disorders. Summing up, reduced cholinesterase activity seems to be associated with the pathogenesis of natural T. evansi infection and its clinical manifestations in buffaloes possibly by evading immune response. Further studies are warranted on association of cholinesterase activity in T. evansi-infected buffaloes with neurological disorders. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis and Preliminary Evaluation of Phenyl 4-123I-Iodophenylcarbamate for Visualization of Cholinesterases Associated with Alzheimer Disease Pathology.

PubMed

Macdonald, Ian R; Reid, G Andrew; Pottie, Ian R; Martin, Earl; Darvesh, Sultan

2016-02-01

Acetylcholinesterase and butyrylcholinesterase accumulate with brain β-amyloid (Aβ) plaques in Alzheimer disease (AD). The overall activity of acetylcholinesterase is found to decline in AD, whereas butyrylcholinesterase has been found to either increase or remain the same. Although some cognitively normal older adults also have Aβ plaques within the brain, cholinesterase-associated plaques are generally less abundant in such individuals. Thus, brain imaging of cholinesterase activity associated with Aβ plaques has the potential to distinguish AD from cognitively normal older adults, with or without Aβ accumulation, during life. Current Aβ imaging agents are not able to provide this distinction. To address this unmet need, synthesis and evaluation of a cholinesterase-binding ligand, phenyl 4-(123)I-iodophenylcarbamate ((123)I-PIP), is described. Phenyl 4-iodophenylcarbamate was synthesized and evaluated for binding potency toward acetylcholinesterase and butyrylcholinesterase using enzyme kinetic analysis. This compound was subsequently rapidly radiolabeled with (123)I and purified by high-performance liquid chromatography. Autoradiographic analyses were performed with (123)I-PIP using postmortem orbitofrontal cortex from cognitively normal and AD human brains. Comparisons were made with an Aβ imaging agent, 2-(4'-dimethylaminophenyl)-6-(123)I-iodo-imidazo[1,2-a]pyridine ((123)I-IMPY), in adjacent brain sections. Tissues were also stained for Aβ and cholinesterase activity to visualize Aβ plaque load for comparison with radioligand uptake. Synthesized and purified PIP exhibited binding to cholinesterases. (123)I was successfully incorporated into this ligand. (123)I-PIP autoradiography with human tissue revealed accumulation of radioactivity only in AD brain tissues in which Aβ plaques had cholinesterase activity. (123)I-IMPY accumulated in brain tissues with Aβ plaques from both AD and cognitively normal individuals. Radiolabeled ligands specific for cholinesterases have potential for use in neuroimaging AD plaques during life. The compound herein described, (123)I-PIP, can detect cholinesterases associated with Aβ plaques and can distinguish AD brain tissues from those of cognitively normal older adults with Aβ plaques. Imaging cholinesterase activity associated with Aβ plaques in the living brain may contribute to the definitive diagnosis of AD during life. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

A direct method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels

PubMed Central

Jaganathan, Lakshmanan; Boopathy, Rathanam

2000-01-01

Background In vertebrates, two types of cholinesterases exist, acetylcholinesterase and butyrylcholinesterase. The function of acetylcholinesterase is to hydrolyse acetylcholine, thereby terminating the neurotransmission at cholinergic synapse, while the precise physiological function of butyrylcholinesterase has not been identified. The presence of cholinesterases in tissues that are not cholinergically innervated indicate that cholinesterases may have functions unrelated to neurotransmission. Furthermore, cholinesterases display a genuine aryl acylamidase activity apart from their predominant acylcholine hydrolase activity. The physiological significance of this aryl acylamidase activity is also not known. The study on the aryl acylamidase has been, in part hampered by the lack of a specific method to visualise this activity. We have developed a method to visualise the aryl acylamidase activity on cholinesterase in polyacrylamide gels. Results The o-nitroaniline liberated from o-nitroacetanilide by the action of aryl acylamidase activity on cholinesterases, in the presence of nitrous acid formed a diazonium compound. This compound gave an azo dye complex with N-(1-napthyl)-ethylenediamine, which appeared as purple bands in polyacrylamide gels. Treating the stained gels with trichloroacetic acid followed by Tris-HCl buffer helped in fixation of the stain in the gels. By using specific inhibitors for acetylcholinesterase and butyrylcholinesterase, respectively, differential staining for the aryl acylamidase activities on butyrylcholinesterase and acetylcholinesterase in a sample containing both these enzymes has been demonstrated. A linear relationship between the intensity of colour developed and activity of the enzyme was obtained. Conclusions A novel method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels has been developed. PMID:11231883

A direct method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels.

PubMed

Jaganathan, L; Boopathy, R

2000-01-01

In vertebrates, two types of cholinesterases exist, acetylcholinesterase and butyrylcholinesterase. The function of acetylcholinesterase is to hydrolyse acetylcholine, thereby terminating the neurotransmission at cholinergic synapse, while the precise physiological function of butyrylcholinesterase has not been identified. The presence of cholinesterases in tissues that are not cholinergically innervated indicate that cholinesterases may have functions unrelated to neurotransmission. Furthermore, cholinesterases display a genuine aryl acylamidase activity apart from their predominant acylcholine hydrolase activity. The physiological significance of this aryl acylamidase activity is also not known. The study on the aryl acylamidase has been, in part hampered by the lack of a specific method to visualise this activity. We have developed a method to visualise the aryl acylamidase activity on cholinesterase in polyacrylamide gels. The o-nitroaniline liberated from o-nitroacetanilide by the action of aryl acylamidase activity on cholinesterases, in the presence of nitrous acid formed a diazonium compound. This compound gave an azo dye complex with N-(1-napthyl)-ethylenediamine, which appeared as purple bands in polyacrylamide gels. Treating the stained gels with trichloroacetic acid followed by Tris-HCl buffer helped in fixation of the stain in the gels. By using specific inhibitors for acetylcholinesterase and butyrylcholinesterase, respectively, differential staining for the aryl acylamidase activities on butyrylcholinesterase and acetylcholinesterase in a sample containing both these enzymes has been demonstrated. A linear relationship between the intensity of colour developed and activity of the enzyme was obtained. A novel method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels has been developed.

Cholinesterase-based biosensors.

PubMed

Štěpánková, Šárka; Vorčáková, Katarína

2016-01-01

Recently, cholinesterase-based biosensors are widely used for assaying anticholinergic compounds. Primarily biosensors based on enzyme inhibition are useful analytical tools for fast screening of inhibitors, such as organophosphates and carbamates. The present review is aimed at compilation of the most important facts about cholinesterase based biosensors, types of physico-chemical transduction, immobilization strategies and practical applications.

Cholinesterase Inhibitors for Lewy Body Disorders: A Meta-Analysis

PubMed Central

Yasue, Ichiro; Iwata, Nakao

2016-01-01

Background: We performed a meta-analysis of cholinesterase inhibitors for patients with Lewy body disorders, such as Parkinson’s disease, Parkinson’s disease dementia, and dementia with Lewy bodies. Methods: The meta-analysis included only randomized controlled trials of cholinesterase inhibitors for Lewy body disorders. Results: Seventeen studies (n = 1798) were assessed. Cholinesterase inhibitors significantly improved cognitive function (standardized mean difference [SMD] = −0.53], behavioral disturbances (SMD = −0.28), activities of daily living (SMD = −0.28), and global function (SMD = −0.52) compared with control treatments. Changes in motor function were not significantly different from control treatments. Furthermore, the cholinesterase inhibitor group had a higher all-cause discontinuation (risk ratio [RR] = 1.48, number needed to harm [NNH] = 14), discontinuation due to adverse events (RR = 1.59, NNH = 20), at least one adverse event (RR = 1.13, NNH = 11), nausea (RR = 2.50, NNH = 13), and tremor (RR = 2.30, NNH = 20). Conclusions: Cholinesterase inhibitors appear beneficial for the treatment of Lewy body disorders without detrimental effects on motor function. However, a careful monitoring of treatment compliance and side effects is required. PMID:26221005

Chronic Neuropsychological Sequelae of Cholinesterase Inhibitors in the Absence of Structural Brain Damage: Two Cases of Acute Poisoning

PubMed Central

Roldán-Tapia, Lola; Leyva, Antonia; Laynez, Francisco; Santed, Fernando Sánchez

2005-01-01

Here we describe two cases of carbamate poisoning. Patients AMF and PVM were accidentally poisoned by cholinesterase inhibitors. The medical diagnosis in both cases was overcholinergic syndrome, as demonstrated by exposure to cholinesterase inhibitors. The widespread use of cholinesterase inhibitors, especially as pesticides, produces a great number of human poisoning events annually. The main known neurotoxic effect of these substances is cholinesterase inhibition, which causes cholinergic overstimulation. Once AMF and PVM had recovered from acute intoxication, they were subjected to extensive neuropsychological evaluation 3 and 12 months after the poisoning event. These assessments point to a cognitive deficit in attention, memory, perceptual, and motor domains 3 months after intoxication. One year later these sequelae remained, even though the brain magnetic resonance imaging (MRI) and computed tomography (CT) scans were interpreted as being within normal limits. We present these cases as examples of neuropsychological profiles of long-term sequelae related to acute poisoning by cholinesterase inhibitor pesticides and show the usefulness of neuropsychological assessment in detecting central nervous system dysfunction in the absence of biochemical or structural markers. PMID:15929901

Brain cDNA clone for human cholinesterase

DOE Office of Scientific and Technical Information (OSTI.GOV)

McTiernan, C.; Adkins, S.; Chatonnet, A.

1987-10-01

A cDNA library from human basal ganglia was screened with oligonucleotide probes corresponding to portions of the amino acid sequence of human serum cholinesterase. Five overlapping clones, representing 2.4 kilobases, were isolated. The sequenced cDNA contained 207 base pairs of coding sequence 5' to the amino terminus of the mature protein in which there were four ATG translation start sites in the same reading frame as the protein. Only the ATG coding for Met-(-28) lay within a favorable consensus sequence for functional initiators. There were 1722 base pairs of coding sequence corresponding to the protein found circulating in human serum.more » The amino acid sequence deduced from the cDNA exactly matched the 574 amino acid sequence of human serum cholinesterase, as previously determined by Edman degradation. Therefore, our clones represented cholinesterase rather than acetylcholinesterase. It was concluded that the amino acid sequences of cholinesterase from two different tissues, human brain and human serum, were identical. Hybridization of genomic DNA blots suggested that a single gene, or very few genes coded for cholinesterase.« less

A diazonium ion cascade from the nitrosation of tolazoline, an imidazoline-containing drug.

PubMed

Loeppky, Richard N; Shi, Jianzheng; Barnes, Charles L; Geddam, Sailaja

2008-02-01

Tolazoline (1-benzylimidazoline), a representative imidazoline-containing drug, reacts readily with nitrite in acetic acid to produce a complex product mixture. Fourteen compounds have been identified as products of this transformation when an 8-fold excess of HNO2 is used. The products, which include N-nitrosoamides, esters, alcohols, and phenylacetic acid, are rationalized as arising from a cascade of reactive diazonium ions. N-Nitrosotolazoline can be isolated from the nitrosation reaction in good yield when the mixture is extracted with CH2Cl2 as the transformation progresses. It nitrosates much more rapidly (50x) than tolazoline to give, among other products, the oxime [1-( N-nitroso-2-imidazolinyl)benzylidene]hydroxylamine, which can also be produced in good yield from the reaction of tolazoline with isopropyl nitrite. At low substrate and nitrite concentrations, the main reaction products are N-nitrosotolazoline, its decomposition product N-2-hydroxyethylphenylacetamide, the above-mentioned oxime, phenyl acetic acid, and 2-hydroxyethyl phenylacetate. The tolazoline nitrosation rate in three buffer systems has been determined at pH 3.4 and 37 degrees C ( kobs = 6.25 x 10 (-5) s (-1) in 0.5 M acetate buffer with a 10 * [NO2(-)] = 250 mM). Because N-nitrosotolazoline exhibits the chemical properties of a direct-acting mutagen and carcinogen, we have used the rate data to estimate its level of formation at nitrite concentrations <3 mM. Cursory examination of the nitrosation chemistry of oxymetazoline, a related drug, is primarily focused at its electron-rich aromatic ring.

Experience with a cholinesterase histochemical technique for rectal suction biopsies in the diagnosis of Hirschsprung's disease

PubMed Central

Trigg, P. H.; Belin, R.; Haberkorn, S.; Long, W. J.; Nixon, H. H.; Plaschkes, J.; Spitz, L.; Willital, G. H.

1974-01-01

Cryostat sections from 160 rectal suction biopsies were stained for cholinesterases by the method of Karnovsky and Roots (1964) in an attempt to facilitate the diagnosis of Hirschsprung's disease. The method proved at least as reliable as experienced assessment of paraffin haematoxylin-eosin sections, and appeared to offer the advantages of reduced scanning fatigue and superior demonstration of the increased cholinesterase-positive nerves in Hirschprung's disease. Contrary to the findings of Meier-Ruge (1971) it was not possible to base a diagnosis on mucosal cholinesterase activity. Images PMID:4832300

Assessment of exposure to organophosphate insecticides during spraying in Haiti: monitoring of urinary metabolites and blood cholinesterase levels*

PubMed Central

Warren, McWilson; Spencer, Harrison C.; Churchill, Frederick C.; Francois, Velly Jean; Hippolyte, Robert; Staiger, Michael A.

1985-01-01

Measurement of blood cholinesterase activity and of the urinary metabolites of fenitrothion (p-nitrocresol) and malathion (monocarboxylic acid) was used to assess the exposure to these insecticides of workers in the Haitian malaria control programme and of residents in the sprayed houses. Cholinesterase activity was significantly reduced at the end of the working week in 3 out of 28 fenitrothion workers. Urinary levels of p-nitrocresol (PNC) in the spraymen ranged from 2.2 to 25.2 mg/l. In fenitrothion workers who had no direct contact with spraying (weighers and supervisors), the cholinesterase activity remained ≥ 75% of the normal control value, and the urinary PNC levels were relatively low. Urinary malathion monocarboxylic acid (MCA) levels at the end of the working week ranged between 1.1 and 5.3 mg/l in workers using malathion and their blood cholinesterase activity remained essentially normal. In both groups of workers the cholinesterase levels improved and the urinary excretion of metabolites decreased after 2 days of rest from the spraying operations. In the residents of the sprayed houses, low concentrations of PNC and MCA were detected in the urine 1 day after spraying and measurable but reduced levels were still present after 7 days. In all these cases the cholinesterase activity remained ≥ 75% of the normal control value. PMID:3874716

Effects of cholinesterase inhibitors on the activities and protein levels of cholinesterases in the cerebrospinal fluid of patients with Alzheimer's disease: a review of recent clinical studies.

PubMed

Darreh-Shori, T; Soininen, H

2010-02-01

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by cognitive decline associated with a deficit in cholinergic function. Inhibitors of acetylcholinesterase (AChE) and/or butyrylcholinesterase (BuChE), such as donepezil, galantamine or rivastigmine, are widely prescribed as symptomatic treatments for AD. These agents exhibit a wide variation in their pharmacological properties. Here we review clinical data from 1998 to 2009 investigating the effect of different cholinesterase inhibitor treatments on the levels and activities of cholinesterases in the cerebrospinal fluid (CSF) of AD patients. These studies suggest that treatment with rapidly-reversible cholinesterase inhibitors (e.g. donepezil, galantamine, tacrine) are associated with marked and significant upregulation of AChE activities and protein levels in the CSF of AD patients. In contrast, pseudo-irreversible cholinesterase inhibition (e.g. rivastigmine) is associated with a significant decrease in both CSF AChE and BuChE activities, with no upregulation of CSF protein levels. Additionally, donepezil is associated with a decrease in the level of the AChE-R isoform relative to the synaptic AChE-S isoform, whereas rivastigmine seems to increase this ratio. These findings suggest that these agents exert different effects on CSF cholinesterases. The clinical effects of these pharmacological differences are yet to be fully established.

The progress in the cholinesterase quantification methods.

PubMed

Holas, Ondrej; Musilek, Kamil; Pohanka, Miroslav; Kuca, Kamil

2012-12-01

Determination of acetylcholinesterase and butyrylcholinesterase activity has become an important tool in drug design and discovery as well as in medicine and toxicology. There are a large number of compounds that are able to modulate cholinesterase activity. These compounds can be used for pharmacological management of various disorders (e.g., Alzheimer's disease, myasthenia Gravis). Moreover, organophosphate poisoning is frequently diagnosed via a cholinesterase activity assay. This broad variety of methods has been developed over the past decades for cholinesterase activity quantification. This review provides a summary of the methods that are based on specific properties of cholinesterases and their interactions with native or artificial substrates. The authors also aim to provide an overview of different techniques used for the determination of quantitative cholinesterase activity. Specifically, the authors describe and discuss the manometric, potentiometric, titrimetric, photometric, fluorometric, and radioisotopic methods. Existing methods are able to cover most of the problems that arise during cholinesterase activity determination. Colorimetry according to Ellman has proved to be the most useful and versatile approach. It may be used in various protocols for the determination of pesticide or nerve agent exposure or for the development of new drugs. Its possible improvement lies in optimization of hemoglobin-rich samples. The progress of the most common methods (including Ellman) depends on miniaturization and modern physical platforms (e.g., optical fibers, chip methods, or nanotechnologies).

Oxime ether lipids containing hydroxylated head groups are more superior siRNA delivery agents than their nonhydroxylated counterparts.

PubMed

Gupta, Kshitij; Mattingly, Stephanie J; Knipp, Ralph J; Afonin, Kirill A; Viard, Mathias; Bergman, Joseph T; Stepler, Marissa; Nantz, Michael H; Puri, Anu; Shapiro, Bruce A

2015-01-01

To evaluate the structure-activity relationship of oxime ether lipids (OELs) containing modifications in the hydrophobic domains (chain length, degree of unsaturation) and hydrophilic head groups (polar domain hydroxyl groups) toward complex formation with siRNA molecules and siRNA delivery efficiency of resulting complexes to a human breast cancer cell line (MDA-MB-231). Ability of lipoplex formation between oxime ether lipids with nucleic acids were examined using biophysical techniques. The potential of OELs to deliver nucleic acids and silence green fluorescent protein (GFP) gene was analyzed using MDA-MB-231 and MDA-MB-231/GFP cells, respectively. Introduction of hydroxyl groups to the polar domain of the OELs and unsaturation into the hydrophobic domain favor higher transfection and gene silencing in a cell culture system.

Configurational and conformational preferences in oximes and oxime carbanions. Ab initio study of the syn effect in reactions of oxyimine enolate equivalents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glaser, R.; Streitwieser, A.

1989-09-13

Geometries and relative energies of stationary structures of several conformers of geometrical isomers of NO s-trans-configured acetaldoxime are reported. The calculated energies and geometries agree well with comparable experimental data. Effects of the theoretical model on the NO band lengths are discussed for formaldoxime. The theoretical results suggest that the regiochemistry of enolate equivalents of oxyimines in dissociating solvents is due to the thermodynamic syn preference of the anions. Syn/anti isomerization of the anions (E{sub a} < 26 kcal mol{sup {minus}1}) is rapid even at low temperatures. In contrast, the anti preference of the radicals of acetaldoxime indicates that themore » formation of the syn products in oxidative coupling reactions of the anions of oxime ethers is a kinetic effect.« less

Cognitive and Affective Changes in Mild to Moderate Alzheimer’s Disease Patients Undergoing Switch of Cholinesterase Inhibitors: A 6-Month Observational Study

PubMed Central

Spalletta, Gianfranco; Caltagirone, Carlo; Padovani, Alessandro; Sorbi, Sandro; Attar, Mahmood; Colombo, Delia; Cravello, Luca

2014-01-01

Patients with Alzheimer’s disease after an initial response to cholinesterase inhibitors may complain a later lack of efficacy. This, in association with incident neuropsychiatric symptoms, may worsen patient quality of life. Thus, the switch to another cholinesterase inhibitor could represent a valid therapeutic strategy. The aim of this study was to investigate the effectiveness of the switch from one to another cholinesterase inhibitor on cognitive and affective symptoms in mild to moderate Alzheimer disease patients. Four hundred twenty-three subjects were included from the EVOLUTION study, an observational, longitudinal, multicentre study conducted on Alzheimer disease patients who switched to different cholinesterase inhibitor due either to lack/loss of efficacy or response, reduced tolerability or poor compliance. All patients underwent cognitive and neuropsychiatric assessments, carried out before the switch (baseline), and at 3 and 6-month follow-up. A significant effect of the different switch types was found on Mini-Mental State Examination score during time, with best effectiveness on mild Alzheimer’s disease patients switching from oral cholinesterase inhibitors to rivastigmine patch. Depressive symptoms, when measured using continuous Neuropsychiatric Inventory values, decreased significantly, while apathy symptoms remained stable over the 6 months after the switch. However, frequency of both depression and apathy, when measured categorically using Neuropsychiatric Inventory cut-off scores, did not change significantly during time. In mild to moderate Alzheimer disease patients with loss of efficacy and tolerability during cholinesterase inhibitor treatment, the switch to another cholinesterase inhibitor may represent an important option for slowing cognitive deterioration. The evidence of apathy stabilization and the positive tendency of depressive symptom improvement should definitively be confirmed in double-blind controlled studies. PMID:24586603

Serum cholinesterase is an important prognostic factor in chronic heart failure.

PubMed

Sato, Takamasa; Yamauchi, Hiroyuki; Suzuki, Satoshi; Yoshihisa, Akiomi; Yamaki, Takayoshi; Sugimoto, Koichi; Kunii, Hiroyuki; Nakazato, Kazuhiko; Suzuki, Hitoshi; Saitoh, Shu-ichi; Takeishi, Yasuchika

2015-03-01

We determine the importance of indicators of nutrition including lymphocyte, total protein, albumin, cholinesterase and body mass index, and compare the prognostic significance in chronic heart failure (CHF). We examined consecutive 465 CHF patients (376 males, age 62 ± 14 years) who underwent cardiopulmonary exercise testing, echocardiography and blood examination including indicators of nutrition at the same time in our hospital. The patients were followed up [median period 766 days (interquartile range 500-1060)] to register cardiac deaths and rehospitalization due to worsening heart failure. There were 180 cardiac events during the follow-up periods. Patients with cardiac events had lower cholinesterase level than those without events (P < 0.001). On the receiver operating characteristic analysis, the best cut-off value for cholinesterase was 240 U/l (area under the curve 0.720). In the Kaplan-Meier analysis, patients with cholinesterase <240 U/l had significantly higher cardiac event rates than those with cholinesterase >240 U/l. Multivariable Cox proportional hazards model demonstrated that NYHA class III [hazard ratio (HR): 1.688, 95 % confidence interval (CI) 1.062-2.684, P = 0.027], eGFR (HR: 0.983, 95 % CI 0.971-0.995, P = 0.006), sodium concentration (HR: 0.947, 95 % CI 0.897-0.999, P < 0.046), log BNP (HR: 1.880, 95 % CI 1.509-2.341, P < 0.001), cholinesterase (HR: 0.996, 95 % CI 0.993-0.998, P = 0.002) and exertional periodic breathing (HR: 1.619, 95 % CI 1.098-2.388, P = 0.015) were independent factors to predict adverse clinical outcomes. Serum cholinesterase level was an important prognostic factor in CHF.

Multiple QSAR models, pharmacophore pattern and molecular docking analysis for anticancer activity of α, β-unsaturated carbonyl-based compounds, oxime and oxime ether analogues

NASA Astrophysics Data System (ADS)

Masand, Vijay H.; El-Sayed, Nahed N. E.; Bambole, Mukesh U.; Quazi, Syed A.

2018-04-01

Multiple discrete quantitative structure-activity relationships (QSARs) models were constructed for the anticancer activity of α, β-unsaturated carbonyl-based compounds, oxime and oxime ether analogues with a variety of substituents like sbnd Br, sbnd OH, -OMe, etc. at different positions. A big pool of descriptors was considered for QSAR model building. Genetic algorithm (GA), available in QSARINS-Chem, was executed to choose optimum number and set of descriptors to create the multi-linear regression equations for a dataset of sixty-nine compounds. The newly developed five parametric models were subjected to exhaustive internal and external validation along with Y-scrambling using QSARINS-Chem, according to the OECD principles for QSAR model validation. The models were built using easily interpretable descriptors and accepted after confirming statistically robustness with high external predictive ability. The five parametric models were found to have R2 = 0.80 to 0.86, R2ex = 0.75 to 0.84, and CCCex = 0.85 to 0.90. The models indicate that frequency of nitrogen and oxygen atoms separated by five bonds from each other and internal electronic environment of the molecule have correlation with the anticancer activity.

Role of dbnd NOH intermolecular interactions in oxime derivatives via Crystal structure, Hirshfeld surface, PIXELC and DFT calculations

NASA Astrophysics Data System (ADS)

Purushothaman, Gayathri; Thiruvenkatam, Vijay

2017-11-01

Oximes are building block of organic synthesis and they have wide range applications in laboratories, industries, and pharmaceutical as antidotes. Herein we report the crystal structures of oxime derivative Beta-p-Dimethylaminodeoxybenzionoxime (I) and o-Chloro-p-dimethylaminodeoxybenzion (II) the precursor molecule of o-Chloro-p-dimethylaminodeoxybenzionoxime and their intermolecular interactions studies through Hirshfeld surface & 2D-fingerprint plot analysis along with PIXELC and DFT calculations. The packing arrangements in I and II are driven by Osbnd H⋯N and Osbnd H⋯C interactions respectively. The Osbnd H⋯N hydrogen bonding in I facilitates the formation of the dimer with the motif of R (22(6)), whereas in II absence of oxime moiety (dbnd NOH) restricts the dimer formation. The 2D-fingerprint plot shows the close contacts for the intermolecular interactions in I & II. The PIXELC calculation of II suggests Osbnd H⋯C contributes for intermolecular interaction that stabilizes the crystal packing with the total energy value of 60.4 kcal/mol. The DFT calculation using B3LYP with 6-311G (d, p) functional set for both the derivatives shows a small deviation in the benzene ring (I) and chlorobenzene ring (II) with the RMSD value of 0.5095 Å and 0.8472 Å respectively.

[How aliphatic alcohols and ph affect reactional capability of the horse blood serum cholinesterase at its interaction with organophosphorus inhibitors].

PubMed

Basova, N E; Kormilitsin, B N; Perchenok, A Iu; Rozengart, E V; Saakov, V S; Suvorov, A A

2013-01-01

There was studied action of aliphatic alcohols (ethanol, propanol, isopropanol, n-butanol, isobutanol, secbutanol, tretbetanol) and pH on various kinds of reactional capability the serum cholinesterase. At the alcohols-affected inhibition of the cholinesterase hydrolytic activity, the determining role was played not the total number carbon atoms in the alcohol molecule, but by the "effective length" of the carbohydrate chain. The fact that the presence of alcohols did not affect parameters of the reverse cholinesterase inhibition with onium ions tetramethylammonium and choline allows suggesting the absence of effect solvents on specific acetylcholine sorption in the enzyme active center. With aid of two rows of hydrophobic organophosphorus inhibitors (OPI), we have managed to estimate both the degree and the character itself of the modifying action of alcohols and pH on the process of irreversible inhibition of serum cholinesterase.

"Nonspecific" cholinesterase and acetylcholinesterase in rat tissues: molecular forms, structural and catalytic properties, and significance of the two enzyme systems.

PubMed Central

Vigny, M; Gisiger, V; Massoulié, J

1978-01-01

"Nonspecific" cholinesterase (acylcholine acylhydrolase; EC 3.1.1.8) from various rat tissues has been found to exist in several stable molecular forms that appear as exact counterparts of molecular forms of acetylcholinesterase (acetylcholine hydrolase; EC 3.1.1.7). The sedimentation pattern of cholinesterase was similar to that of acetylcholinesterase with a small but significant shift between the sedimentation coefficients of the corresponding forms. Extraction yields in different media also demonstrated a close parallelism between the two enzyme systems. Other properties, such as thermal stability and catalytic characteristics, indicated both differences and similarities. In spite of the structural resemblance implied by their physicochemical properties, cholinesterase did not crossreact with antibodies against acetylcholinesterase. The nature of the relationships revealed by these studies and their bearing on the physiological significance of cholinesterases are discussed. PMID:78492

A Pharmacokinetic Study of the Effects of Stress and Exercise on Chemical Exposure

DTIC Science & Technology

2001-03-20

Organophosphates such as diazinon and malathion are considered cholinesterase inhibitors, while carbamates such as physostigmine and pyridostigmine...bromide (PB) are considered reversible cholinesterase inhibitors. The possible Gulf War exposures to organophosphates such as diazinon and malathion...indicate that the physiological and protective effects of carbamates such as PB may depend on a narrow range of cholinesterase inhibition. Blood

Unbinding of fluorinated oxime drug from the AChE gorge in polarizable water: a well-tempered metadynamics study.

PubMed

Pathak, Arup Kumar; Bandyopadhyay, Tusar

2017-02-15

Despite the fact that fluorination makes a drug more lipophilic, the molecular level understanding of protein-fluorinated drug interactions is very poor. Due to their enhanced ability to penetrate the blood brain barrier, they are suitable for reactivation of organophosphorus inactivated acetylcholinesterase (AChE) in the central nervous system. We systematically studied the unbinding of fluorinated obidoxime (FOBI) and non-fluorinated obidoxime (OBI) from the active site gorge of the serine hydrolase AChE in mean field polarizable water by employing all atom molecular dynamics simulations. It is observed that the unbinding process is strongly influenced by cation-π, hydrogen bond (HB) and water bridge interactions. The FOBI drug interacts more strongly with the protein residues than OBI and this is also verified from quantum mechanical calculations. Distinct unbinding pathways for FOBI and OBI are observed as evident from the 1D and 2D potential of mean force of the unbinding profiles. The present study suggests that the FOBI drug is held more firmly in the gorge of AChE in comparison to OBI and may lead to higher reactivation efficiency of the inactivated enzyme.

A site-saturated mutagenesis study of pentaerythritol tetranitrate reductase reveals that residues 181 and 184 influence ligand binding, stereochemistry and reactivity.

PubMed

Toogood, Helen S; Fryszkowska, Anna; Hulley, Martyn; Sakuma, Michiyo; Mansell, David; Stephens, Gill M; Gardiner, John M; Scrutton, Nigel S

2011-03-21

We have conducted a site-specific saturation mutagenesis study of H181 and H184 of flavoprotein pentaerythritol tetranitrate reductase (PETN reductase) to probe the role of these residues in substrate binding and catalysis with a variety of α,β-unsaturated alkenes. Single mutations at these residues were sufficient to dramatically increase the enantiopurity of products formed by reduction of 2-phenyl-1-nitropropene. In addition, many mutants exhibited a switch in reactivity to predominantly catalyse nitro reduction, as opposed to CC reduction. These mutants showed an enhancement in a minor side reaction and formed 2-phenylpropanal oxime from 2-phenyl-1-nitropropene. The multiple binding conformations of hydroxy substituted nitro-olefins in PETN reductase were examined by using both structural and catalytic techniques. These compounds were found to bind in both active and inhibitory complexes; this highlights the plasticity of the active site and the ability of the H181/H184 couple to coordinate with multiple functional groups. These properties demonstrate the potential to use PETN reductase as a scaffold in the development of industrially useful biocatalysts. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Absence of neurovisual effects due to tissue and blood cholinesterase depression in a chronic disulfoton feeding study in dogs.

PubMed

Jones, R D; Hastings, T F; Landes, A M

1999-06-01

Technical grade disulfoton (DiSyston) was fed to Beagle dogs (four animals per sex and treatment level) at nominal concentrations of 0, 0.5, 4 and 12 ppm for 1 year. The purpose of this study was to characterize the potential general and neurovisual toxicity according to routine Environmental Protection Agency (EPA) guideline requirements, and by use of ancillary ocular and neurologic tests established in this Laboratory. Ophthalmological tests included: ocular tissue cholinesterase and histopathology, electroretinography (ERG), tracking, refractivity, intraocular pressure and pachymetry (corneal thickness) measurements. Neurological examinations included; peripheral and cranial reflex tests, task performance tests, gait and behavioral observations, and rectal temperature measurements. Plasma, erythrocyte and corneal cholinesterase were significantly depressed at 4 and 12 ppm in both sexes. Brain cholinesterase was depressed at 4 and 12 ppm in females. Retinal cholinesterase was depressed at 4 ppm in females and at 12 ppm in males. Ciliary body cholinesterase was depressed at 12 ppm in both sexes. Despite these cholinergic effects, there were no ophthalmologic findings in measurements of ERG, tracking, refractivity, intraocular pressure or pachymetry. There were no clinical neurology findings related to compound administration. We conclude that 0.5 ppm was a no-observable effect level (NOEL), and effects were limited to cholinesterase changes that had no detectable physiologic impact. This study demonstrates that special mechanistic investigations incorporated within guideline studies, enhances scientific integrity and can minimize the need for dedicated organ system studies.

Identification of the structural mutation responsible for the dibucaine-resistant (atypical) variant form of human serum cholinesterase

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGuire, M.C.; Nogueira, C.P.; Bartels, C.F.

1989-02-01

A point mutation in the gene for human serum cholinesterase was identified that changes Asp-70 to Gly in the atypical form of serum cholinesterase. The mutation in nucleotide 209, which changes codon 70 from GAT to GGT, was found by sequencing a genomic clone and sequencing selected regions of DNA amplified by the polymerase chain reaction. The entire coding sequences for usual and atypical cholinesterases were compared, and no other consistent base differences were found. The nucleotide-209 mutation was detected in all five atypical cholinesterase families examined. There was complete concordance between this mutation and serum cholinesterase phenotypes for allmore » 14 heterozygous and 6 homozygous atypical subjects tested. The mutation causes the loss of a Sau3A1 restriction site; the resulting DNA fragment length polymorphism was verified by electrophoresis of {sup 32}P-labeled DNA restriction fragments from usual and atypical subjects. Dot-blot hybridization analysis with a 19-mer allele-specific probe to the DNA amplified by the polymerase chain reaction distinguished between the usual and atypical genotypes. The authors conclude that the Asp-70 {yields} Gly mutation accounts for reduced affinity of atypical cholinesterase for choline esters and that Asp-70 must be an important component of the anionic site. Heterogeneity in atypical alleles may exist, but the Asp-70 point mutation may represent an appreciable portion of the atypical gene pool.« less

High efficiency labeling of glycoproteins on living cells

PubMed Central

Zeng, Ying; Ramya, T. N. C.; Dirksen, Anouk; Dawson, Philip E.; Paulson, James C.

2010-01-01

We describe a simple method for efficiently labeling cell surface glycans on virtually any living animal cell. The method employs mild Periodate oxidation to generate an aldehyde on sialic acids, followed by Aniline-catalyzed oxime Ligation with a suitable tag (PAL). Aniline catalysis dramatically accelerates oxime ligation, allowing use of low concentrations of aminooxy-biotin at neutral pH to label the majority of cell surface glycoproteins while maintaining high cell viability. PMID:19234450

Theoretical and experimental studies of 3β-acetoxy-5α-cholestan-6-one oxime

NASA Astrophysics Data System (ADS)

Khan, Azhar U.; Avecillia, Fernando; Malik, Nazia; Khan, Md. Shahzad; Khan, Mohd Shahid; Mushtaque, Md.

2016-10-01

Steroidal oxime (3β-acetoxy-5α-cholestan- 6-one oxime) has been synthesized using microwave-induced reaction in 3.5 min using saturated steroidal ketone and aqueous hydroxylamine hydrochloride in ethanol. The structure of the compound was elucidated by UV, IR, 1H NMR and X-ray single crystal structure. The computational quantum chemical studies like, IR, UV analysis were performed by density functional theory (DFT) at Becke-3-Lee-Yang-Parr(B3LYP) exchange-correlation functional in combination with 6-31++G(d,p) basis sets. The harmonic vibrational frequencies, the optimized geometric parameters have been interpreted and compared with experimental values. Theoretical wavelength at 214.88 cm-1 correspond to the experimental value 214.0 cm-1. The nature of this transition is n → π*. The theoretical results are in good agreement with experiment results.

Different approaches to acute organophosphorus poison treatment.

PubMed

Nurulain, Syed Muhammad

2012-07-01

Organophosphorus compounds (OPCs) have a wide variety of applications and are a serious threat for self-poisoning, unintentional misuse, terrorist attack, occupational hazard and warfare attack. The present standard treatment has been reported to be unsatisfactory. Many novel approaches are being used and tested for acute organophosphorus (OP) poison treatment. The bioscavenger concept captured high attention among the scientific community during the last few decades. Other approaches like alkalinisation of blood plasma/serum and use of weak inhibitors against strong inhibitors, though it showed promising results, did not get such wide attention. The introduction of a novel broad-spectrum oxime has also been in focus. In this mini-review, an update of the overview of four different approaches has been discussed. The standard therapy that is atropine+oxime+benzodiazepine along with supportive measures will continue to be the best option with only the replacement of a single oxime to improve its broad-spectrum efficacy.

The HSP90 binding mode of a radicicol-like E-oxime from docking, binding free energy estimations, and NMR 15N chemical shifts

PubMed Central

Spichty, Martin; Taly, Antoine; Hagn, Franz; Kessler, Horst; Barluenga, Sofia; Winssinger, Nicolas; Karplus, Martin

2009-01-01

We determine the binding mode of a macrocyclic radicicol-like oxime to yeast HSP90 by combining computer simulations and experimental measurements. We sample the macrocyclic scaffold of the unbound ligand by parallel tempering simulations and dock the most populated conformations to yeast HSP90. Docking poses are then evaluated by the use of binding free energy estimations with the linear interaction energy method. Comparison of QM/MM-calculated NMR chemical shifts with experimental shift data for a selective subset of back-bone 15N provides an additional evaluation criteria. As a last test we check the binding modes against available structure-activity-relationships. We find that the most likely binding mode of the oxime to yeast HSP90 is very similar to the known structure of the radicicol-HSP90 complex. PMID:19482409

Oxime ether lipids containing hydroxylated head groups are more superior siRNA delivery agents than their nonhydroxylated counterparts

PubMed Central

Gupta, Kshitij; Mattingly, Stephanie J; Knipp, Ralph J; Afonin, Kirill A; Viard, Mathias; Bergman, Joseph T; Stepler, Marissa; Nantz, Michael H; Puri, Anu; Shapiro, Bruce A

2015-01-01

Aim: To evaluate the structure–activity relationship of oxime ether lipids (OELs) containing modifications in the hydrophobic domains (chain length, degree of unsaturation) and hydrophilic head groups (polar domain hydroxyl groups) toward complex formation with siRNA molecules and siRNA delivery efficiency of resulting complexes to a human breast cancer cell line (MDA-MB-231). Materials & methods: Ability of lipoplex formation between oxime ether lipids with nucleic acids were examined using biophysical techniques. The potential of OELs to deliver nucleic acids and silence green fluorescent protein (GFP) gene was analyzed using MDA-MB-231 and MDA-MB-231/GFP cells, respectively. Results & conclusion: Introduction of hydroxyl groups to the polar domain of the OELs and unsaturation into the hydrophobic domain favor higher transfection and gene silencing in a cell culture system. PMID:26107486

In vitro characterization of pralidoxime transport and acetylcholinesterase reactivation across MDCK cells and stem cell-derived human brain microvascular endothelial cells (BC1-hBMECs).

PubMed

Gallagher, Erin; Minn, Il; Chambers, Janice E; Searson, Peter C

2016-07-11

Current therapies for organophosphate poisoning involve administration of oximes, such as pralidoxime (2-PAM), that reactivate the enzyme acetylcholinesterase. Studies in animal models have shown a low concentration in the brain following systemic injection. To assess 2-PAM transport, we studied transwell permeability in three Madin-Darby canine kidney (MDCKII) cell lines and stem cell-derived human brain microvascular endothelial cells (BC1-hBMECs). To determine whether 2-PAM is a substrate for common brain efflux pumps, experiments were performed in the MDCKII-MDR1 cell line, transfected to overexpress the P-gp efflux pump, and the MDCKII-FLuc-ABCG2 cell line, transfected to overexpress the BCRP efflux pump. To determine how transcellular transport influences enzyme reactivation, we developed a modified transwell assay where the inhibited acetylcholinesterase enzyme, substrate, and reporter are introduced into the basolateral chamber. Enzymatic activity was inhibited using paraoxon and parathion. The permeability of 2-PAM is about 2 × 10(-6) cm s(-1) in MDCK cells and about 1 × 10(-6) cm s(-1) in BC1-hBMECs. Permeability is not influenced by pre-treatment with atropine. In addition, 2-PAM is not a substrate for the P-gp or BCRP efflux pumps. The low permeability explains poor brain penetration of 2-PAM and therefore the slow enzyme reactivation. This elucidates one of the reasons for the necessity of sustained intravascular (IV) infusion in response to organophosphate poisoning.

Cholinesterase Inhibitors and Hospitalization for Bradycardia: A Population-Based Study

PubMed Central

Park-Wyllie, Laura Y.; Mamdani, Muhammad M.; Li, Ping; Gill, Sudeep S.; Laupacis, Andreas; Juurlink, David N.

2009-01-01

Background Cholinesterase inhibitors are commonly used to treat dementia. These drugs enhance the effects of acetylcholine, and reports suggest they may precipitate bradycardia in some patients. We aimed to examine the association between use of cholinesterase inhibitors and hospitalization for bradycardia. Methods and Findings We examined the health care records of more than 1.4 million older adults using a case-time-control design, allowing each individual to serve as his or her own control. Case patients were residents of Ontario, Canada, aged 67 y or older hospitalized for bradycardia between January 1, 2003 and March 31, 2008. Control patients (3∶1) were not hospitalized for bradycardia, and were matched to the corresponding case on age, sex, and a disease risk index. All patients had received cholinesterase inhibitor therapy in the 9 mo preceding the index hospitalization. We identified 1,009 community-dwelling older persons hospitalized for bradycardia within 9 mo of using a cholinesterase inhibitor. Of these, 161 cases informed the matched analysis of discordant pairs. Of these, 17 (11%) required a pacemaker during hospitalization, and six (4%) died prior to discharge. After adjusting for temporal changes in drug utilization, hospitalization for bradycardia was associated with recent initiation of a cholinesterase inhibitor (adjusted odds ratio [OR] 2.13, 95% confidence interval [CI] 1.29–3.51). The risk was similar among individuals with pre-existing cardiac disease (adjusted OR 2.25, 95% CI 1.18–4.28) and those receiving negative chronotropic drugs (adjusted OR 2.34, 95% CI 1.16–4.71). We found no such association when we replicated the analysis using proton pump inhibitors as a neutral exposure. Despite hospitalization for bradycardia, more than half of the patients (78 of 138 cases [57%]) who survived to discharge subsequently resumed cholinesterase inhibitor therapy. Conclusions Among older patients, initiation of cholinesterase inhibitor therapy was associated with a more than doubling of the risk of hospitalization for bradycardia. Resumption of therapy following discharge was common, suggesting that the cardiovascular toxicity of cholinesterase inhibitors is underappreciated by clinicians. Please see later in the article for the Editors' Summary PMID:19787032

Pharmacokinetics of bambuterol in subjects homozygous for the atypical gene for plasma cholinesterase

PubMed Central

Bang, Ulla; Nyberg, Lars; Rosenborg, Johan; Viby-Mogensen, Jørgen

1998-01-01

Aims It has been assumed that both plasma cholinesterase (EC 3.1.1.8) and oxidative enzymes are needed for optimum formation of the bronchodilator terbutaline from its biscarbamate prodrug bambuterol. The present study aimed at investigating the fate of bambuterol in subjects with deficient plasma cholinesterase but with normal oxidative (CYP2D6) capability. Methods The pharmacokinetics of bambuterol and terbutaline were studied in four healthy subjects (two men and two women) being homozygous for the atypical gene for plasma cholinesterase. Their oxidative metabolism was apparently good as they were all rapid metabolizers of debrisoquine. Bambuterol hydrochloride 20 mg was given orally once daily for 10 days, and plasma and urine samples were taken for 1.5 days (plasma) and 4.5 days (urine) after administration of the last dose. Results The pharmacokinetic parameters in the present study were grossly similar to those found in a study of bambuterol in subjects with normal plasma cholinesterase activity (N). However, subjects with atypical cholinesterase had a shorter terminal half-life of bambuterol (a measure of uptake rate), 4.8–12.6 h vs 8.3–22.3 h in N, and slightly higher plasma concentrations of bambuterol (average concentrations 1.9–3.7 nmol l−1vs 1.5–3.1 nmol l−1 in N). Peak/trough terbutaline plasma concentrations ratios (2.1–3.2) were somewhat increased, but average plasma concentrations (8.3–14.5 nmol l−1) and terminal half-life (16.5–21.8 h) of terbutaline did not differ. Conclusions In Caucasian populations, one subject out of 2500 is homozygous for the atypical gene for plasma cholinesterase. The atypical enzyme has a much lower affinity for bambuterol than the normal enzyme. Nevertheless, the subjects with atypical cholinesterase were able to produce terbutaline as efficiently as normal subjects. This might be explained by an altered uptake and metabolism in the absence of plasma cholinesterase, or the importance of this enzyme for the formation of terbutaline from bambuterol in vivo may have been overestimated. PMID:9643621

Localization of cholinesterases in the chicken nervous system and the problem of the selective neurotoxicity of organophosphorus compounds

PubMed Central

Cavanagh, J. B.; Holland, P.

1961-01-01

Using the thiocholine method, a restricted survey has been made of cholinesterases in the spinal cord and brain stem of the chicken. No simple relation between sites of selective damage in organophosphorus neurotoxicity and centres of cholinesterase activity could be adduced. Moreover, no significant differences between species susceptible and insusceptible to poisoning by these compounds were found by this method. It is concluded that, while cholinesterase may well play an intermediary role in the intoxication, other factors determine the selective damage to certain neurones and their processes. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6 PMID:13691740

Regional cholinesterase activity in white-throated sparrow brain is differentially affected by acephate (Orthene®)

USGS Publications Warehouse

Vyas, N.B.; Kuenzel, W.J.; Hill, E.F.; Romo, G.A.; Komaragiri, M.V.S.

1996-01-01

Effects of a 14-day dietary exposure to an organophosphorus pesticide, acephate (acetylphosphoramidothioic acid O,S-dimethyl ester), were determined on cholinesterase activity in three regions (basal ganglia, hippocampus, and hypothalamus) of the white-throated sparrow, Zonotrichia albicollis, brain. All three regions experienced depressed cholinesterase activity between 0.5–2 ppm acephate. The regions exhibited cholinesterase recovery at 2–16 ppm acephate; however, cholinesterase activity dropped and showed no recovery at higher dietary levels (>16 ppm acephate). Evidence indicates that the recovery is initiated by the magnitude of depression, not the duration. In general, as acephate concentration increased, differences in ChE activity among brain regions decreased. Three terms are introduced to describe ChE response to acephate exposure: 1) ChE resistance threshold, 2) ChE compensation threshold, and 3) ChE depression threshold. It is hypothesized that adverse effects to birds in the field may occur at pesticide exposure levels customarily considered negligible.

Cholinesterase inhibitory effects of Rhizophora lamarckii, Avicennia officinalis, Sesuvium portulacastrum and Suaeda monica: Mangroves inhabiting an Indian coastal area (Vellar Estuary).

PubMed

Suganthy, Natarajan; Pandian, Shanmugiahthevar Karutha; Devi, Kasi Pandima

2009-06-01

Alzheimer's disease is a progressive neurodegenerative illness accounting for approximately 50% of all types of dementia in elderly people. The only symptomatic treatment proven effective to date is the use of cholinesterase inhibitors to augment surviving cholinergic activity. The purpose of this study is to investigate cholinesterase inhibitory activity of mangroves as an alternative medicine for the treatment of Alzheimer's disease. About nine mangrove plants, which were used as folk medicine in tropical countries, were collected from Parangipettai, Vellar estuary, Tamilnadu, India. Nile Tilapia muscle homogenate was used as source of enzyme. Inhibitory effect of methanolic leaf extract was assessed under in vitro condition by incubating various concentration of the extract with total cholinesterase and butyryl cholinesterase and assessing their residual activities by Ellman's colorimetric method. The results showed that of the nine plants screened Rhizophora lamarckii, Suaeda monica, Avicennia officinalis and Sesuvium portulacastrum showed 50% inhibitory activity to both TChE and BChE at concentrations less than 2 mg/mL when compared to other plant extracts, which was comparable to the standard drug Donepezil. Phytochemical analysis showed the presence of alkaloids in high concentration which might be correlated to its cholinesterase inhibitory activity.

Chemical constituents and their acetyl cholinesterase inhibitory and antioxidant activities from leaves of Acanthopanax henryi: potential complementary source against Alzheimer's disease.

PubMed

Zhang, Xiao Dan; Liu, Xiang Qian; Kim, Yang Hee; Whang, Wan Kyunn

2014-05-01

The aim of this study was to investigate chemical constituents of the leaves of Acanthopanax henryi, and their antioxidant, acetyl cholinesterase inhibitory activities. Caffeoyl quinic acid derivates and flavonoids were obtained from A. henry, through column chromatography technologies, and the content of major constituents was determined by the HPLC-UV method. Anti-oxidant activity of the isolated metabolites was evaluated by free radical scavenging (DPPH, ABTS radicals) and superoxide anion scavenging. The results showed that di-caffeoyl quinic acid derivates had stronger antioxidant activity than positive controls (ascorbic acid, trolox and allopurinol). Acetyl cholinesterase inhibitory activity was estimated on the constituents, among which, quercetin, 4-caffeoyl-quinic acid and 4,5-caffeoyl quinic acid were found to have strong acetyl cholinesterase inhibitory activity with IC50 values ranging from 62.6 to 121.9 μM. The present study showed that some of the tested constituents from the leaves of A. henryi exhibit strong antioxidant and acetyl cholinesterase inhibitory effects. This suggest that the leaves of A. henryi can be used as a new natural complementary source of acetyl cholinesterase inhibitors and anti-oxidant agents, thus being a promising potential complementary source against Alzheimer's disease.

Behavioral changes and cholinesterase activity of rats acutely treated with propoxur.

PubMed

Thiesen, F V; Barros, H M; Tannhauser, M; Tannhauser, S L

1999-01-01

Early assessment of neurological and behavioral effects is extremely valuable for early identification of intoxications because preventive measures can be taken against more severe or chronic toxic consequences. The time course of the effects of an oral dose of the anticholinesterase agent propoxur (8.3 mg/kg) was determined on behaviors displayed in the open-field and during an active avoidance task by rats and on blood and brain cholinesterase activity. Maximum inhibition of blood cholinesterase was observed within 30 min after administration of propoxur. The half-life of enzyme-activity recovery was estimated to be 208.6 min. Peak brain cholinesterase inhibition was also detected between 5 and 30 min of the pesticide administration, but the half-life for enzyme activity recovery was much shorter, in the range of 85 min. Within this same time interval of the enzyme effects, diminished motor and exploratory activities and decreased performance of animals in the active avoidance task were observed. Likewise, behavioral normalization after propoxur followed a time frame similar to that of brain cholinesterase. These data indicate that behavioral changes that occur during intoxication with low oral doses of propoxur may be dissociated from signs characteristic of cholinergic over-stimulation but accompany brain cholinesterase activity inhibition.

Protease inhibitors and indoleamines selectively inhibit cholinesterases in the histopathologic structures of Alzheimer disease.

PubMed Central

Wright, C I; Guela, C; Mesulam, M M

1993-01-01

Neurofibrillary tangles and amyloid plaques express acetylcholinesterase and butyrylcholinesterase activity in Alzheimer disease. We previously reported that traditional acetylcholinesterase inhibitors such as BW284C51, tacrine, and physostigmine were more potent inhibitors of the acetylcholinesterase in normal axons and cell bodies than of the acetylcholinesterase in plaques and tangles. We now report that the reverse pattern is seen with indoleamines (such as serotonin and its precursor 5-hydroxytryptophan), carboxypeptidase inhibitor, and the nonspecific protease inhibitor bacitracin. These substances are more potent inhibitors of the cholinesterases in plaques and tangles than of those in normal axons and cell bodies. These results show that the enzymatic properties of plaque and tangle-associated cholinesterases diverge from those of normal axons and cell bodies. The selective susceptibility to bacitracin and carboxypeptidase inhibitor indicates that the catalytic sites of plaque and tangle-bound cholinesterases are more closely associated with peptidase or protease-like properties than the catalytic sites of cholinesterases in normal axons and cell bodies. This shift in enzymatic affinity may lead to the abnormal protein processing that is thought to play a major role in the pathogenesis of Alzheimer disease. The availability of pharmacological and dietary means for altering brain indoleamines raises therapeutic possibilities for inhibiting the abnormal cholinesterase activity associated with Alzheimer disease. Images PMID:8421706

Natural genomic amplification of cholinesterase genes in animals.

PubMed

Chatonnet, Arnaud; Lenfant, Nicolas; Marchot, Pascale; Selkirk, Murray E

2017-08-01

Tight control of the concentration of acetylcholine at cholinergic synapses requires precise regulation of the number and state of the acetylcholine receptors, and of the synthesis and degradation of the neurotransmitter. In particular, the cholinesterase activity has to be controlled exquisitely. In the genome of the first experimental models used (man, mouse, zebrafish and drosophila), there are only one or two genes coding for cholinesterases, whereas there are more genes for their closest relatives the carboxylesterases. Natural amplification of cholinesterase genes was first found to occur in some cancer cells and in insect species subjected to evolutionary pressure by insecticides. Analysis of the complete genome sequences of numerous representatives of the various metazoan phyla show that moderate amplification of cholinesterase genes is not uncommon in molluscs, echinoderms, hemichordates, prochordates or lepidosauria. Amplification of acetylcholinesterase genes is also a feature of parasitic nematodes or ticks. In these parasites, over-production of cholinesterase-like proteins in secreted products and the saliva are presumed to have effector roles related to host infection. These amplification events raise questions about the role of the amplified gene products, and the adaptation processes necessary to preserve efficient cholinergic transmission. This is an article for the special issue XVth International Symposium on Cholinergic Mechanisms. © 2017 International Society for Neurochemistry.

New Organocatalyst Scaffolds with High Activity in Promoting Hydrazone and Oxime Formation at Neutral pH

PubMed Central

2015-01-01

The discovery of two new classes of catalysts for hydrazone and oxime formation in water at neutral pH, namely 2-aminophenols and 2-(aminomethyl)benzimidazoles, is reported. Kinetics studies in aqueous solutions at pH 7.4 revealed rate enhancements up to 7-fold greater than with classic aniline catalysis. 2-(Aminomethyl)benzimidazoles were found to be effective catalysts with otherwise challenging aryl ketone substrates. PMID:25545888

Aminooxylated Carbohydrates: Synthesis and Applications.

PubMed

Pifferi, Carlo; Daskhan, Gour Chand; Fiore, Michele; Shiao, Tze Chieh; Roy, René; Renaudet, Olivier

2017-08-09

Among other classes of biomolecules, carbohydrates and glycoconjugates are widely involved in numerous biological functions. In addition to addressing the related synthetic challenges, glycochemists have invested intense efforts in providing access to structures that can be used to study, activate, or inhibit these biological processes. Over the past few decades, aminooxylated carbohydrates have been found to be key building blocks for achieving these goals. This review provides the first in-depth overview covering several aspects related to the syntheses and applications of aminooxylated carbohydrates. After a brief introduction to oxime bonds and their relative stabilities compared to related C═N functions, synthetic aspects of oxime ligation and methodologies for introducing the aminooxy functionality onto both glycofuranosyls and glycopyranosyls are described. The subsequent section focuses on biological applications involving aminooxylated carbohydrates as components for the construcion of diverse architectures. Mimetics of natural structures represent useful tools for better understanding the features that drive carbohydrate-receptor interaction, their biological output and they also represent interesting structures with improved stability and tunable properties. In the next section, multivalent structures such as glycoclusters and glycodendrimers obtained through oxime ligation are described in terms of synthetic design and their biological applications such as immunomodulators. The second-to-last section discusses miscellaneous applications of oxime-based glycoconjugates, such as enantioselective catalysis and glycosylated oligonucleotides, and conclusions and perspectives are provided in the last section.

Detoxification of tabun at physiological pH mediated by substituted β-cyclodextrin and glucose derivatives containing oxime groups.

PubMed

Brandhuber, Florian; Zengerle, Michael; Porwol, Luzian; Tenberken, Oliver; Thiermann, Horst; Worek, Franz; Kubik, Stefan; Reiter, Georg

2012-12-16

The ability of 13 β-cyclodextrin and 2 glucose derivatives containing substituents with oxime groups as nucleophilic components to accelerate the degradation of tabun at physiological pH has been evaluated. To this end, a qualitative and a quantitative enzymatic assay as well as a highly sensitive enantioselective GC-MS assay were used. In addition, an assay was developed that provided information about the mode of action of the investigated compounds. The results show that attachment of pyridinium-derived substituents with an aldoxime group in 3- or 4-position to a β-cyclodextrin ring affords active compounds mediating tabun degradation. Activities differ depending on the structure, the number, and the position of the substituent on the ring. Highest activity was observed for a β-cyclodextrin containing a 4-formylpyridinium oxime residue in 6-position of one glucose subunit, which detoxifies tabun with a half-time of 10.2 min. Comparison of the activity of this compound with that of an analog in which the cyclodextrin ring was replaced by a glucose residue demonstrated that the cyclodextrin is not necessary for activity but certainly beneficial. Finally, the results provide evidence that the mode of action of the cyclodextrin involves covalent modification of its oxime group rendering the scavenger inactive after reaction with the first tabun molecule. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Identification of the structural mutation responsible for the dibucaine-resistant (atypical) variant form of human serum cholinesterase.

PubMed Central

McGuire, M C; Nogueira, C P; Bartels, C F; Lightstone, H; Hajra, A; Van der Spek, A F; Lockridge, O; La Du, B N

1989-01-01

A point mutation in the gene for human serum cholinesterase was identified that changes Asp-70 to Gly in the atypical form of serum cholinesterase. The mutation in nucleotide 209, which changes codon 70 from GAT to GGT, was found by sequencing a genomic clone and sequencing selected regions of DNA amplified by the polymerase chain reaction. The entire coding sequences for usual and atypical cholinesterases were compared, and no other consistent base differences were found. A polymorphic site near the C terminus of the coded region was detected, but neither allele at this locus segregated consistently with the atypical trait. The nucleotide-209 mutation was detected in all five atypical cholinesterase families examined. There was complete concordance between this mutation and serum cholinesterase phenotypes for all 14 heterozygous and 6 homozygous atypical subjects tested. The mutation causes the loss of a Sau3A1 restriction site; the resulting DNA fragment length polymorphism was verified by electrophoresis of 32P-labeled DNA restriction fragments from usual and atypical subjects. Dot-blot hybridization analysis with a 19-mer allele-specific probe to the DNA amplified by the polymerase chain reaction distinguished between the usual and atypical genotypes. We conclude that the Asp-70----Gly mutation (acidic to neutral amino acid substitution) accounts for reduced affinity of atypical cholinesterase for choline esters and that Asp-70 must be an important component of the anionic site. Heterogeneity in atypical alleles may exist, but the Asp-70 point mutation may represent an appreciable portion of the atypical gene pool. Images PMID:2915989

Aerosolized delivery of oxime MMB-4 in combination with atropine sulfate protects against soman exposure in guinea pigs.

PubMed

Perkins, Michael W; Pierre, Zdenka; Sabnekar, Praveena; Sciuto, Alfred M; Song, Jian; Soojhawon, Iswarduth; Oguntayo, Samuel; Doctor, Bhupendra P; Nambiar, Madhusoodana P

2012-08-01

We evaluated the efficacy of aerosolized acetylcholinesterase (AChE) reactivator oxime MMB-4 in combination with the anticholinergic atropine sulfate for protection against respiratory toxicity and lung injury following microinstillation inhalation exposure to nerve agent soman (GD) in guinea pigs. Anesthetized animals were exposed to GD (841 mg/m(3), 1.2 LCt(50)) and treated with endotracheally aerosolized MMB-4 (50 µmol/kg) plus atropine sulfate (0.25 mg/kg) at 30 sec post-exposure. Treatment with MMB-4 plus atropine increased survival to 100% compared to 38% in animals exposed to GD. Decreases in the pulse rate and blood O(2) saturation following exposure to GD returned to normal levels in the treatment group. The body-weight loss and lung edema was significantly reduced in the treatment group. Similarly, bronchoalveolar cell death was significantly reduced in the treatment group while GD-induced increase in total cell count was decreased consistently but was not significant. GD-induced increase in bronchoalveolar protein was diminished after treatment with MMB-4 plus atropine. Bronchoalveolar lavage AChE and BChE activity were significantly increased in animals treated with MMB-4 plus atropine at 24 h. Lung and diaphragm tissue also showed a significant increase in AChE activity in the treatment group. Treatment with MMB-4 plus atropine sulfate normalized various respiratory dynamics parameters including respiratory frequency, tidal volume, peak inspiratory and expiratory flow, time of inspiration and expiration, enhanced pause and pause post-exposure to GD. Collectively, these results suggest that aerosolization of MMB-4 plus atropine increased survival, decreased respiratory toxicity and lung injury following GD inhalation exposure.

Observation and explanation of two-dimensional interconversion of oximes with multiple heart-cutting using comprehensive multidimensional gas chromatography.

PubMed

Kulsing, Chadin; Nolvachai, Yada; Wong, Yong Foo; Glouzman, Melissa I; Marriott, Philip J

2018-04-20

Real-time interconversion processes produce unconventional peak broadening in gas chromatography (GC), and can be used to generate kinetic and thermodynamic data. In this study, an unusual separation situation in comprehensive two dimensional GC where two dimensional interconversion (i.e. a raised plateau in both first and second dimension, 1 D and 2 D) was observed in analysis of oxime isomers. This resulted in a characteristic and unusual rectangular peak shape in the two dimensional result. A related theoretical approach was introduced to explain the peak shape supported by simulation results which can be varied depending on concentration profiles and kinetics of the process. The simulated results were supported by experimental results obtained by a comprehensive heart-cut multidimensional GC (H/C MDGC) approach which was developed to clearly investigate isomerisation of E/Z oxime molecules in both 1 D and 2 D separations under different isothermal conditions. The carrier gas flow and oven temperature were selected according to initial results for 1D interconversion on a poly(ethyleneglycol) stationary phase, which was further used in both 1 D and 2 D separations to result in broad zones of oxime interconversion in both dimensions. The method involved repetitive injections of oxime sample, then sampling contiguous fractions of sample into a long 2 D column which is intended to promote considerable interconversion. Comprehensiveness arises from the fact that the whole sample is sampled from the 1 D to the 2 D column, with the long 2 D column replacing the short 2 D column used in classical comprehensive two-dimensional gas chromatography, where the latter will not promote sufficient interconversion. Data processing and presentation permits a 'rectangular' distribution corresponding to the separated compounds, characteristic of this experiment. Copyright © 2018 Elsevier B.V. All rights reserved.

Current Pyridostigmine Bromide and Huperzine A Studies and Future Cholinesterase Screening Using the WRAIR Whole Blood Cholinesterase Assay

DTIC Science & Technology

2004-11-15

1 CURRENT PYRIDOSTIGMINE BROMIDE AND HUPERZINE A STUDIES AND FUTURE CHOLINESTERASE SCREENING USING THE WRAIR WHOLE BLOOD...selective (e.g. Huperzine A ) and non-selective (carbamate) inhibitors (e.g. pyridostigmine bromide, PB). We found that volunteers given pyridostigmine...profile of healthy elderly volunteers receiving Huperzine A . 52.7 ± 1.5% inhibition was observed at the end of an increasing dose regimen (final dose

Acute Toxicity Estimation and Operational Risk Management of Chemical Warfare Agent Exposures

DTIC Science & Technology

2004-05-01

Following absorption into the body, nerve agents bind with and inhibit the activity of cholinesterases (ChE) that are present in the blood and...other tissues. Blood ChE activity depression by itself is not considered an adverse effect but (particularly red blood cell cholinesterase (RBC-ChE...chemical, such as an organophosphate , that blocks nerve impulses by inhibiting the activity of the enzyme cholinesterase (adapted from University of

[Methods for determination of cholinesterase activity].

PubMed

Dingová, D; Hrabovská, A

2015-01-01

Cholinesterases hydrolyze acetylcholine and thus they play a key role in a process of cholinergic neurotransmission. Changes in their activities are linked to many diseases (e.g Alzheimer disease, Parkinson disease, lipid disorders). Thus, it is important to determine their activity in a fast, simply and precise way. In this review, different approaches of studying cholinesterase activities (e.g pH-dependent, spectrophotometric, radiometric, histochemical methods or biosensors) are discussed. Comparisons, advantages or disadvantages of selected methods (e.g most widely used Ellman's assay, extremely sensitive Johnson Russell method or modern technique with golden nanoparticles) are presented. This review enables one to choose a suitable method for determination of cholinesterase activities with respect to laboratory equipment, type of analysis, pH, temperature scale or special conditions.

Rh(III)-Catalyzed Decarboxylative Coupling of Acrylic Acids with Unsaturated Oxime Esters: Carboxylic Acids Serve as Traceless Activators

PubMed Central

2015-01-01

α,β-Unsaturated carboxylic acids undergo Rh(III)-catalyzed decarboxylative coupling with α,β-unsaturated O-pivaloyl oximes to provide substituted pyridines in good yield. The carboxylic acid, which is removed by decarboxylation, serves as a traceless activating group, giving 5-substituted pyridines with very high levels of regioselectivity. Mechanistic studies rule out a picolinic acid intermediate, and an isolable rhodium complex sheds further light on the reaction mechanism. PMID:24512241

Application of oxime-diversification to optimize ligand interactions within a cryptic pocket of the polo-like kinase 1 polo-box domain | Center for Cancer Research

Cancer.gov

By a process involving initial screening of a set of 87 aldehydes using an oxime ligation-based strategy, we were able to achieve a several-fold affinity enhancement over one of the most potent previously known polo-like kinase 1 (Plk1) polo-box domain (PBD) binding inhibitors. This improved binding may result by accessing a newly identified auxiliary region proximal to a key

Perspectives on the Use of Scopolamine as an Adjunct Treatment to Enhance Survival Following Organophosphorus Nerve Agent Poisoning

DTIC Science & Technology

2010-11-01

particular nerve agent and oxime uti- lized in the treatment regimen. Atropine is the universal treatment for organophospho- rus anticholinesterase poisoning...general, to the recovery of AChE activity either through decarbamylation of PB protected enzyme or by use of an effective oxime. The results against...this protected enzyme in the first few minutes after intoxication and treat- ment provides sufficient enzyme activity to sustain survival.̂ ’"* A

Detection of homing-in of stem cells labeled with technetium-99m hexamethylpropyleneamine oxime in infarcted myocardium after intracoronary injection

PubMed Central

Patel, Chetan D; Agarwal, Snehlata; Seth, Sandeep; Mohanty, Sujata; Aggarwal, Himesh; Gupta, Namit

2014-01-01

Bone marrow stem cells having myogenic potential are promising candidates for various cell-based therapies for myocardial disease. We present here images showing homing of technetium-99m (Tc-99m) hexamethylpropyleneamine oxime (HMPAO) labeled stem cells in the infarcted myocardium from a pilot study conducted to radio-label part of the stem cells in patients enrolled in a stem cell clinical trial for recent myocardial infarction. PMID:25400375

Influence of cholinesterase inhibitors, donepezil and rivastigmine on the acquisition, expression, and reinstatement of morphine-induced conditioned place preference in rats.

PubMed

Gawel, Kinga; Labuz, Krzysztof; Jenda, Malgorzata; Silberring, Jerzy; Kotlinska, Jolanta H

2014-07-15

The influence of systemic administration of cholinesterase inhibitors, donepezil and rivastigmine on the acquisition, expression, and reinstatement of morphine-induced conditioned place preference (CPP) was examined in rats. Additionally, this study aimed to compare the effects of donepezil, which selectively inhibits acetylcholinesterase, and rivastigmine, which inhibits both acetylcholinesterase and butyrylcholinesterase on morphine reward. Morphine-induced CPP (unbiased method) was induced by four injections of morphine (5 mg/kg, i.p.). Donepezil (0.5, 1, and 3 mg/kg, i.p.) or rivastigmine (0.03, 0.5, and 1 mg/kg, i.p.) were given 20 min before morphine during conditioning phase and 20 min before the expression or reinstatement of morphine-induced CPP. Our results indicated that both inhibitors of cholinesterase attenuated the acquisition and expression of morphine CPP. The results were more significant after rivastigmine due to a broader inhibitory spectrum of this drug. Moreover, donepezil (1 mg/kg) and rivastigmine (0.5 mg/kg) attenuated the morphine CPP reinstated by priming injection of 5mg/kg morphine. These properties of both cholinesterase inhibitors were reversed by mecamylamine (3 mg/kg, i.p.), a nicotinic acetylcholine receptor antagonist but not scopolamine (0.5 mg/kg, i.p.), a muscarinic acetylcholine receptor antagonist. All effects of cholinesterase inhibitors were observed at the doses that had no effects on locomotor activity of animals. Our results suggest beneficial role of cholinesterase inhibitors in reduction of morphine reward and morphine-induced seeking behavior. Finally, we found that the efficacy of cholinesterase inhibitors in attenuating reinstatement of morphine CPP provoked by priming injection may be due to stimulation of nicotinic acetylcholine receptors. Copyright © 2014 Elsevier B.V. All rights reserved.

The influence of cholinesterase inhibitor therapy for dementia on risk of cardiac pacemaker insertion: a retrospective, population-based, health administrative databases study in Ontario, Canada.

PubMed

Huang, Allen R; Redpath, Calum J; van Walraven, Carl

2015-04-28

Cholinesterase inhibitors are used to treat the symptoms of dementia and can theoretically cause bradycardia. Previous studies suggest that patients taking these medications have an increased risk of undergoing pacemaker insertion. Since these drugs have a marginal impact on patient outcomes, it might be preferable to change drug treatment rather than implant a pacemaker. This population-based study determined the association of people with dementia exposed to cholinesterase inhibitor medication and pacemaker insertion. We used data from the Ontario health administrative databases from January 1, 1993 to June 30, 2012. We included all community-dwelling seniors who had a code for dementia and were exposed to cholinesterase inhibitors (donezepil, galantamine, and rivastigmine) and/or drugs used to treat co-morbidities of hypertension, diabetes, depression and hypothyroidism. We controlled for exposure to anti-arrhythmic drugs. Observation started at first exposure to any medication and continued until the earliest of pacemaker insertion, death, or end of study. 2,353,909 people were included with 96,000 (4.1%) undergoing pacemaker insertion during the observation period. Case-control analysis showed that pacemaker patients were less likely to be coded with dementia (unadjusted OR 0.42 [95%CI 0.41-0.42]) or exposed to cholinesterase inhibitors (unadjusted OR 0.39 [95%CI 0.37-0.41]). That Cohort analysis showed patients with dementia taking cholinesterase inhibitors had a decreased risk of pacemaker insertion (unadj-HR 0.58 [0.55-0.61]). Adjustment for patient age, sex, and other medications did not notably change results, as did restricting the analysis to incident users. Patients taking cholinesterase inhibitors rarely undergo, and have a significantly reduced risk of, cardiac pacemaker insertion.

Cholinesterase activity during embryonic development in the blood-feeding bug Triatoma patagonica.

PubMed

Visciarelli, E C; Chopa, C Sánchez; Picollo, M I; Ferrero, A A

2011-09-01

Triatoma patagonica Del Ponte (Hemiptera: Reduviidae), a vector of Chagas' disease, is widely distributed in Argentina and is found in sylvatic and peridomiciliary ecotopes, as well as occasionally in human dwellings after the chemical control of Triatoma infestans. Anti-cholinesteratic products can be applied in peridomiciliary areas and thus knowledge of cholinesterase activity during embryonic development in this species might contribute further information relevant to effective chemical control. Cholinesterase activity was characterized by reactions to eserine 10(-5) m, to increasing concentrations of substrate and to varying centrifugal speeds. Acetylcholinesterase activity was detected on day 4 and was significant from day 5. A reduction in cholinesterase activity towards acetylthiocholine (ATC) was observed on days 9 and 10 of development. Cholinesterase activity towards ATC and butyrylthiocholine (BTC) in homogenates of eggs was inhibited by eserine 10(-5) m. The shape of the curve indicating levels of inhibition at different concentrations of ATC was typical of acetylcholinesterase. Activity towards BTC did not appear to be inhibited by excess substrate, which parallels the behaviour of butyrylcholinesterases. Cholinesterase activity towards ATC was reduced in supernatant centrifuged at 15 000 g compared with supernatant centrifuged at 1100 g. The cholinesterase system that hydrolyzes mainly ATC seems to belong to the nervous system, as indicated by its behaviour towards the substrates assayed, its greater insolubility and the fact that it evolves parallel to the development of the nervous system. Knowledge of biochemical changes associated with the development and maturation of the nervous system during embryonic development would contribute to the better understanding of anti-cholinesteratic compounds with ovicidal action that might be used in control campaigns against vectors of Chagas' disease. © 2011 The Authors. Medical and Veterinary Entomology © 2011 The Royal Entomological Society.

Effect of pomegranate extracts on brain antioxidant markers and cholinesterase activity in high fat-high fructose diet induced obesity in rat model.

PubMed

Amri, Zahra; Ghorbel, Asma; Turki, Mouna; Akrout, Férièle Messadi; Ayadi, Fatma; Elfeki, Abdelfateh; Hammami, Mohamed

2017-06-27

To investigate beneficial effects of Pomegranate seeds oil (PSO), leaves (PL), juice (PJ) and (PP) on brain cholinesterase activity, brain oxidative stress and lipid profile in high-fat-high fructose diet (HFD) induced-obese rat. In vitro and in vivo cholinesterase activity, brain oxidative status, body and brain weight and plasma lipid profile were measured in control rats, HFD-fed rats and HFD-fed rats treated by PSO, PL, PJ and PP. In vitro study showed that PSO, PL, PP, PJ inhibited cholinesterase activity in dose dependant manner. PL extract displayed the highest inhibitory activity by IC50 of 151.85 mg/ml. For in vivo study, HFD regime induced a significant increase of cholinesterase activity in brain by 17.4% as compared to normal rats. However, the administration of PSO, PL, PJ and PP to HDF-rats decreased cholinesterase activity in brain respectively by 15.48%, 6.4%, 20% and 18.7% as compared to untreated HFD-rats. Moreover, HFD regime caused significant increase in brain stress, brain and body weight, and lipid profile disorders in blood. Furthermore, PSO, PL, PJ and PP modulated lipid profile in blood and prevented accumulation of lipid in brain and body evidenced by the decrease of their weights as compared to untreated HFD-rats. In addition administration of these extract protected brain from stress oxidant, evidenced by the decrease of malondialdehyde (MDA) and Protein carbonylation (PC) levels and the increase in superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels. These findings highlight the neuroprotective effects of pomegranate extracts and one of mechanisms is the inhibition of cholinesterase and the stimulation of antioxidant capacity.

WRAIR Protocols for Soldier Status and Readiness to Organophosphate Exposure: Unprocessed Whole Blood Cholinesterase and Pyridostigmine Bromide Quantification

DTIC Science & Technology

2003-07-01

blood in the presence and absence of selective ( huperzine - a and Iso-OMPA), and non-selective (pyridostigmine bromide) cholinesterase inhibitors...cholinesterases after exposure to CWAs such as GD and pharmaceuticals such as huperzine - a and pyridostigmine have been determined in animals and man...activity. Since urban terrorism is on the rise, Federal,State, and local authorities need a reliable, fast, inexpensive method for confirming such an

Phosphorylated Derivatives of Alkaloids and Nitrogen-containing Heterocycles — Cholinesterase Inhibitors

NASA Astrophysics Data System (ADS)

Sadykov, Abid S.; Dalimov, D. N.; Godovikov, Nikolai N.

1983-10-01

The review deals with the synthesis and anticholinesterase activities of phosphorylated derivatives of certain alkaloids and nitrogen-containing heterocycles. It is shown that the conformational properties of the alkaloid and nitrogen-containing heterocycle residues in the composition of the organophosphorus inhibitor (OPI) molecule play an important role in the inhibition of the catalytic activity of cholinesterases. The type of inhibition of cholinesterases also varies as a function of chemical structure. The bibliography includes 45 references.

An Evaluation of Blood Cholinesterase Testing Methods for Military Health

DTIC Science & Technology

2008-05-01

activity found that only one device has been validated for ChE testing in the field: the Model 400 Test-mate™ ChE kit by EQM Research, Inc. (Cincinnati...OH). Suggested future modifications to the Model 400 Test-mate™ ChE kit include displaying/recording of acetyl-ChE activity uncorrected for...cholinesterase activity , that are routinely monitored by the Department of Defense (DoD). Within DoD, definitive cholinesterase testing is conducted by

Japanese quail acute exposure to methamidophos: experimental design, lethal, sub-lethal effects and cholinesterase biochemical and histochemical expression.

PubMed

Foudoulakis, Manousos; Balaskas, Christos; Csato, Attila; Szentes, Csaba; Arapis, Gerassimos

2013-04-15

We exposed the Japanese quail (Coturnix coturnix japonica) to the organophosphate methamidophos using acute oral test. Mortality and sub-lethal effects were recorded in accordance to internationally accepted protocols. In addition cholinesterases were biochemically estimated in tissues of the quail: brain, liver and plasma. Furthermore, brain, liver and duodenum cryostat sections were processed for cholinesterase histochemistry using various substrates and inhibitors. Mortalities occurred mainly in the first 1-2h following application. Sub-lethal effects, such as ataxia, ruffled feathers, tremor, salivation and reduced or no reaction to external stimuli were observed. Biochemical analysis in the brain, liver and plasma indicates a strong cholinesterase dependent inhibition with respect to mortality and sub-lethal effects of the quail. The histochemical staining also indicated a strong cholinesterase inhibition in the organs examined and the analysis of the stained sections allowed for an estimation and interpretation of the intoxication effects of methamidophos, in combination with tissue morphology visible by Haematoxylin and Eosin staining. We conclude that the use of biochemistry and histochemistry for the biomarker cholinesterase, may constitute a significantly novel approach for understanding the results obtained by the acute oral test employed in order to assess the effects of methamidophos and other chemicals known to inhibit this very important nervous system enzyme. Copyright © 2012 Elsevier B.V. All rights reserved.

Syntheses, cholinesterases inhibition, and molecular docking studies of pyrido[2,3-b]pyrazine derivatives.

PubMed

Hameed, Abdul; Zehra, Syeda T; Shah, Syed J A; Khan, Khalid M; Alharthy, Rima D; Furtmann, Norbert; Bajorath, Jürgen; Tahir, Muhammad N; Iqbal, Jamshed

2015-11-01

Cholinesterases, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), have a role in cholinergic deficit which evidently leads to Alzheimer's disease (AD). Inhibition of cholinesterases with small molecules is an attractive strategy in AD therapy. This study demonstrates synthesis of pyrido[2,3-b]pyrazines (6a-6q) series, their inhibitory activities against both cholinesterases, AChE and BChE, and molecular docking studies. The bioactivities data of pyrido[2,3-b]pyrazines showed 3-(3'-nitrophenyl)pyrido[2,3-b]pyrazine 6n a potent dual inhibitor among the series against both AChE and BChE with IC50 values of 0.466 ± 0.121 and 1.89 ± 0.05 μm, respectively. The analogues 3-(3'-methylphenyl)pyrido[2,3-b]pyrazine 6c and 3-(3'-fluorophenyl)pyrido[2,3-b]pyrazine 6f were found to be selective inhibition for BChE with IC50 values of 0.583 ± 0.052 μm and AChE with IC50 value of 0.899 ± 0.10 μm, respectively. Molecular docking studies of the active compounds suggested the putative binding modes with cholinesterases. The potent compounds among the series could potentially serves as good leads for the development of new cholinesterase inhibitors. © 2015 John Wiley & Sons A/S.

21 CFR 520.2520e - Trichlorfon boluses.

Code of Federal Regulations, 2012 CFR

2012-04-01

... § 510.600(c) of this chapter. (c) Special considerations. Trichlorfon is a cholinesterase inhibitor. Do... or exposure to, neuromuscular depolarizing agents (i.e., succinylcholine) or to cholinesterase...

21 CFR 520.2520e - Trichlorfon boluses.

Code of Federal Regulations, 2014 CFR

2014-04-01

... § 510.600(c) of this chapter. (c) Special considerations. Trichlorfon is a cholinesterase inhibitor. Do... or exposure to, neuromuscular depolarizing agents (i.e., succinylcholine) or to cholinesterase...

21 CFR 520.2520e - Trichlorfon boluses.

Code of Federal Regulations, 2013 CFR

2013-04-01

... § 510.600(c) of this chapter. (c) Special considerations. Trichlorfon is a cholinesterase inhibitor. Do... or exposure to, neuromuscular depolarizing agents (i.e., succinylcholine) or to cholinesterase...

21 CFR 520.2520e - Trichlorfon boluses.

Code of Federal Regulations, 2011 CFR

2011-04-01

... § 510.600(c) of this chapter. (c) Special considerations. Trichlorfon is a cholinesterase inhibitor. Do... or exposure to, neuromuscular depolarizing agents (i.e., succinylcholine) or to cholinesterase...

Tracking the origin and divergence of cholinesterases and neuroligins: the evolution of synaptic proteins.

PubMed

Lenfant, Nicolas; Hotelier, Thierry; Bourne, Yves; Marchot, Pascale; Chatonnet, Arnaud

2014-07-01

A cholinesterase activity can be found in all kingdoms of living organism, yet cholinesterases involved in cholinergic transmission appeared only recently in the animal phylum. Among various proteins homologous to cholinesterases, one finds neuroligins. These proteins, with an altered catalytic triad and no known hydrolytic activity, display well-identified cell adhesion properties. The availability of complete genomes of a few metazoans provides opportunities to evaluate when these two protein families emerged during evolution. In bilaterian animals, acetylcholinesterase co-localizes with proteins of cholinergic synapses while neuroligins co-localize and may interact with proteins of excitatory glutamatergic or inhibitory GABAergic/glycinergic synapses. To compare evolution of the cholinesterases and neuroligins with other proteins involved in the architecture and functioning of synapses, we devised a method to search for orthologs of these partners in genomes of model organisms representing distinct stages of metazoan evolution. Our data point to a progressive recruitment of synaptic components during evolution. This finding may shed light on the common or divergent developmental regulation events involved into the setting and maintenance of the cholinergic versus glutamatergic and GABAergic/glycinergic synapses.

Quantitative estimation of cholinesterase-specific drug metabolism of carbamate inhibitors provided by the analysis of the area under the inhibition-time curve.

PubMed

Zhou, Huimin; Xiao, Qiaoling; Tan, Wen; Zhan, Yiyi; Pistolozzi, Marco

2017-09-10

Several molecules containing carbamate groups are metabolized by cholinesterases. This metabolism includes a time-dependent catalytic step which temporary inhibits the enzymes. In this paper we demonstrate that the analysis of the area under the inhibition versus time curve (AUIC) can be used to obtain a quantitative estimation of the amount of carbamate metabolized by the enzyme. (R)-bambuterol monocarbamate and plasma butyrylcholinesterase were used as model carbamate-cholinesterase system. The inhibition of different concentrations of the enzyme was monitored for 5h upon incubation with different concentrations of carbamate and the resulting AUICs were analyzed. The amount of carbamate metabolized could be estimated with <15% accuracy (RE%) and ≤23% precision (RSD%). Since the knowledge of the inhibition kinetics is not required for the analysis, this approach could be used to determine the amount of drug metabolized by cholinesterases in a selected compartment in which the cholinesterase is confined (e.g. in vitro solutions, tissues or body fluids), either in vitro or in vivo. Copyright © 2017 Elsevier B.V. All rights reserved.

[Effects of cornel iridoid glycoside on activity of cholinesterases in vitro].

PubMed

Chu, Si-Juan; Zhang, Lan; Liu, Gang; Zhou, Wen-Xia; Li, Lin

2013-05-01

The purpose of the present study was to investigate the effects of cornel iridoid glycoside (CIG) on the activity of cholinesterases in vitro, and to investigate the mechanism of CIG's treating Alzheimer's disease (AD). The sources of cholinesterases were prepared from human blood cells, rat brain homogenate and human blood plasma, respectively. The biochemical methods were used to detect the activity of acetylcholine esterase (AChE) and butyryl cholinesterase (BuChE) to investigate the influence of CIG on cholinesterases. The results showed that CIG inhibited the activity of AChE of human blood cells and rat brain homogenate, with the 50% inhibition rate (IC50) of 1.6 g . L-1 and 3.3 g . L-1, respectively; and the inhibition of AChE of CIG is reversible. CIG also inhibited the activity of BuChE of human blood plasma, with the IC50 of 2.9 g . L-1. In conclusion, CIG can inhibit the activity of AChE and BuChE in vitro, which may be one of the mechanisms of CIG to treat AD.

Determination of Carbonyl Functional Groups in Bio-oils by Potentiometric Titration: The Faix Method.

PubMed

Black, Stuart; Ferrell, Jack R

2017-02-07

Carbonyl compounds present in bio-oils are known to be responsible for bio-oil property changes upon storage and during upgrading. Specifically, carbonyls cause an increase in viscosity (often referred to as 'aging') during storage of bio-oils. As such, carbonyl content has previously been used as a method of tracking bio-oil aging and condensation reactions with less variability than viscosity measurements. Additionally, carbonyls are also responsible for coke formation in bio-oil upgrading processes. Given the importance of carbonyls in bio-oils, accurate analytical methods for their quantification are very important for the bio-oil community. Potentiometric titration methods based on carbonyl oximation have long been used for the determination of carbonyl content in pyrolysis bio-oils. Here, we present a modification of the traditional carbonyl oximation procedures that results in less reaction time, smaller sample size, higher precision, and more accurate carbonyl determinations. While traditional carbonyl oximation methods occur at room temperature, the Faix method presented here occurs at an elevated temperature of 80 °C.

Fe-polyaniline composite nanofiber catalyst for chemoselective hydrolysis of oxime.

PubMed

Mahato, Sanjit Kumar; Bhaumik, Madhumita; Maji, Arun; Dutta, Abhijit; Maiti, Debabrata; Maity, Arjun

2018-03-01

A facile chemoselective one-pot strategy for the deprotection of oxime has been developed using Fe 0 -polyaniline composite nanofiber (Fe 0 -PANI), as a catalyst. Nano material based Fe 0 -PANI catalyst has been synthesized via in-situ polymerization of ANI monomer and followed by reductive deposition of Fe 0 onto PANI matrix. The catalyst was characterized by FE-SEM, HR-TEM, BET, XRD, ATR-FTIR, XPS and VSM techniques. The scope of the transformation was studied for aryl, alkyl and heteroarylketoxime with excellent chemoselectivity (>99%). Mechanistic investigations suggested the involvement of a cationic intermediate with Fe 3+ active catalytic species. Substituent effect showed a linear free energy relationship. The activation energy (E a ) was calculated to be 17.46 kJ mol -1 for acetophenone oxime to acetophenone conversion. The recyclability of the catalyst demonstrated up to 10 cycles without any significant loss of efficiency. Based on the preliminary experiments a plausible mechanism has been proposed involving a carbocationic intermediate. Copyright © 2017 Elsevier Inc. All rights reserved.

Synthesis of 3,5-Isoxazolidinediones and 1H-2,3-Benzoxazine-1,4(3H)-diones from Aliphatic Oximes and Dicarboxylic Acid Chlorides

PubMed Central

2015-01-01

The synthesis of the title compounds was carried out by reacting dicarboxylic acid chlorides with oximes in the presence of excess triethylamine. Disubstituted malonyl chlorides gave 2-alkenyl-4,4-dialkyl-3,5-isoxazolidinediones (8a–f) and 2,2′-ethylidene-bis[4,4-dialkyl-3,5-isoxazolidinedione]s (9a–f). Compounds 9 were formed from 8 and its N-unsubstituted 3,5-isoxazolidinedione decomposition product. Phthaloyl chlorides reacted with acetone oxime to yield 3-(1-methylethenyl)-1H-2,3-benzoxazine-1,4(3H)-diones (16a–e). Products 16 spontaneously decomposed to give N-unsubstituted 1H-2,3-benzoxazine-1,4(3H)-diones (17a–e) at rates that were dependent on temperature and solvent. Kinetic studies showed that two of the compounds decomposed by zero-order kinetics under neutral conditions. Butanedioyl chloride did not produce a cyclic product. PMID:24620711

Synthesis of 3,5-isoxazolidinediones and 1H-2,3-benzoxazine-1,4(3H)-diones from aliphatic oximes and dicarboxylic acid chlorides.

PubMed

Izydore, Robert A; Jones, Joseph T; Mogesa, Benjamin; Swain, Ira N; Davis-Ward, Ronda G; Daniels, Dwayne L; Kpakima, Felicia Frazier; Spaulding-Phifer, Sharnelle T

2014-04-04

The synthesis of the title compounds was carried out by reacting dicarboxylic acid chlorides with oximes in the presence of excess triethylamine. Disubstituted malonyl chlorides gave 2-alkenyl-4,4-dialkyl-3,5-isoxazolidinediones (8a-f) and 2,2'-ethylidene-bis[4,4-dialkyl-3,5-isoxazolidinedione]s (9a-f). Compounds 9 were formed from 8 and its N-unsubstituted 3,5-isoxazolidinedione decomposition product. Phthaloyl chlorides reacted with acetone oxime to yield 3-(1-methylethenyl)-1H-2,3-benzoxazine-1,4(3H)-diones (16a-e). Products 16 spontaneously decomposed to give N-unsubstituted 1H-2,3-benzoxazine-1,4(3H)-diones (17a-e) at rates that were dependent on temperature and solvent. Kinetic studies showed that two of the compounds decomposed by zero-order kinetics under neutral conditions. Butanedioyl chloride did not produce a cyclic product.

DFT conformational studies of the HI-6 molecule

NASA Astrophysics Data System (ADS)

Silva, Gustavo R.; Borges, Itamar; Figueroa-Villar, Jose D.

A systematic study of the oxime HI-6 [1-(2-hydroxyiminomethyl-1-pyridinium)-1-(4-carboxy-aminopyridinium)dimethyl ether] hydrochloride, which is one of the most promising antidotes against soman intoxication, was carried out using density functional theory with the B3LYP (Becke, Lee, Yang, and Parr) method and the 6-31+G*, 6-31+G*, and 6-31+G** basis sets. Rotational barriers, equilibrium geometries, and charge distributions were calculated in order to investigate the role of the side chain for the larger oximes used as antidotes in the treatment of neurotoxic organophosphate poisoning. Also reported is the comparison between HI-6 and pralidoxime (2-PAM), a smaller oxime previously studied in our research group. It is shown that conformation minima for the protonated E isomer do not depend on the size of the side chain; on the other hand, this effect has a pronounced influence on the protonated Z isomer. For the unprotonated isomers, other effects, such as electrostatic interactions and resonance, should be taken into account in their conformational analysis.

Cholinesterase inhibitors from botanicals

PubMed Central

Ahmed, Faiyaz; Ghalib, Raza Murad; Sasikala, P.; Ahmed, K. K. Mueen

2013-01-01

Alzheimer's disease (AD) is a progressive neurodegenerative disease, wherein a progressive loss of cholinergic synapses occurs in hippocampus and neocortex. Decreased concentration of the neurotransmitter, acetylcholine (ACh), appears to be critical element in the development of dementia, and the most appropriate therapeutic approach to treat AD and other form of dementia is to restore acetylcholine levels by inhibiting both major form of cholinesterase: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Consequently, researches have focused their attention towards finding cholinesterase inhibitors from natural products. A large number of such inhibitors have been isolated from medicinal plants. This review presents a comprehensive account of the advances in field of cholinesterase inhibitor phytoconstituents. The structures of some important phytoconstituents (collected through www.Chemspider.com) are also presented and the scope for future research is discussed. PMID:24347920

Spectroscopic and pH-metric studies of the complexation of 3-[2-(4-methylquinolin-2-yl)hydrazono]butan-2-one oxime compound.

PubMed

Seleem, H S; El-Inany, G A; Mousa, M; Hanafy, F I

2010-05-01

The electronic absorption spectra of the oximic quinolinyl hydrazone (MHQ; H(2)L) and its Co(II) and Cu(II)-complexes have been studied in Britton-Rhobinson buffer solutions of varying pH's in 75% dioxane-water. The dissociation constant of the hydrazone (pK(H)) as well as the stability constants (logK) of its chelates were determined spectrophotometrically and pH-metrically. The obtained data are in good agreement. Beer's law is valid in the ranges (0.64-6.99) and (2.36-6.48)mug/mL for Cu(II) and Co(II)-ions, respectively. On the other hand, the pK(H) and logK were determined pH-metrically in 75% solvent-water; (solvent=dioxane, ethanol, methanol and isopropanol). The variation of pK(H) or logK as a function of solvent parameters viz. 1/D, E(T), AN and pi* was used to evaluate the dissociation and stability constants in the aqueous medium. Furthermore, the reaction of the oximic hydrazone (H(2)L) with copper(II)-nitrate and chloride in addition to copper(I)-iodide afforded square planar mononuclear and binuclear complexes in which the oximic hydrazone showed three different modes of bonding. The obtained complexes reflect the strong bridging ability of the oximato group as well as its ambidentate and flexidentate characters. Copyright 2010 Elsevier B.V. All rights reserved.

21 CFR 520.2520f - Trichlorfon granules.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 000856 in § 510.600(c) of this chapter. (c) Special considerations. Trichlorfon is a cholinesterase... treatment with or exposure to neuromuscular depolarizing agents (i.e., succinylcholine) or to cholinesterase...

21 CFR 520.2520f - Trichlorfon granules.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 000856 in § 510.600(c) of this chapter. (c) Special considerations. Trichlorfon is a cholinesterase... treatment with or exposure to neuromuscular depolarizing agents (i.e., succinylcholine) or to cholinesterase...

Understanding Alzheimer's

MedlinePlus

... donepezil), and Cognex (tacrine). They are known as cholinesterase inhibitors. Scientists believe they prevent the breakdown of acetylcholine, ... the brain produces less and less acetylcholine; therefore, cholinesterase inhibitors may eventually lose their effect. Treatment for Moderate ...

40 CFR 156.206 - General statements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (i.e., an organophosphorus ester that inhibits cholinesterase) or an N-methyl carbamate (i.e., an N-methyl carbamic acid ester that inhibits cholinesterase), the label shall so state. The statement shall...

40 CFR 156.206 - General statements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (i.e., an organophosphorus ester that inhibits cholinesterase) or an N-methyl carbamate (i.e., an N-methyl carbamic acid ester that inhibits cholinesterase), the label shall so state. The statement shall...

40 CFR 156.206 - General statements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (i.e., an organophosphorus ester that inhibits cholinesterase) or an N-methyl carbamate (i.e., an N-methyl carbamic acid ester that inhibits cholinesterase), the label shall so state. The statement shall...

40 CFR 156.206 - General statements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (i.e., an organophosphorus ester that inhibits cholinesterase) or an N-methyl carbamate (i.e., an N-methyl carbamic acid ester that inhibits cholinesterase), the label shall so state. The statement shall...

Use of a novel radiometric method to assess the inhibitory effect of donepezil on acetylcholinesterase activity in minimally diluted tissue samples

PubMed Central

Kikuchi, Tatsuya; Okamura, Toshimitsu; Arai, Takuya; Obata, Takayuki; Fukushi, Kiyoshi; Irie, Toshiaki; Shiraishi, Tetsuya

2010-01-01

Background and purpose: Cholinesterase inhibitors have been widely used for the treatment of patients with dementia. Monitoring of the cholinesterase activity in the blood is used as an indicator of the effect of the cholinesterase inhibitors in the brain. The selective measurement of cholinesterase with low tissue dilution is preferred for accurate monitoring; however, the methods have not been established. Here, we investigated the effect of tissue dilution on the action of cholinesterase inhibitors using a novel radiometric method with selective substrates, N-[14C]methylpiperidin-4-yl acetate ([14C]MP4A) and (R)-N-[14C]methylpiperidin-3-yl butyrate ([14C]MP3B_R), for AChE and butyrylcholinesterase (BChE) respectively. Experimental approach: We investigated the kinetics of hydrolysis of [14C]-MP4A and [14C]-MP3B_R by cholinesterases, and evaluated the selectivity of [14C]MP4A and [14C]MP3B_R for human AChE and BChE, respectively, compared with traditional substrates. Then, IC50 values of cholinesterase inhibitors in minimally diluted and highly diluted tissues were measured with [14C]MP4A and [14C]MP3B_R. Key results: AChE and BChE activities were selectively measured as the first-order hydrolysis rates of [14C]-MP4A and [14C]MP3B_R respectively. The AChE selectivity of [14C]MP4A was an order of magnitude higher than traditional substrates used for the AChE assay. The IC50 values of specific AChE and BChE inhibitors, donepezil and ethopropazine, in 1.2-fold diluted human whole blood were much higher than those in 120-fold diluted blood. In addition, the IC50 values of donepezil in monkey brain were dramatically decreased as the tissue was diluted. Conclusions and implications: This method would effectively monitor the activity of cholinesterase inhibitors used for therapeutics, pesticides and chemical warfare agents. PMID:20401964

21 CFR 520.1631 - Oxfendazole and trichlorfon paste.

Code of Federal Regulations, 2011 CFR

2011-04-01

.... Trichlorfon is a cholinesterase inhibitor. Do not use this product in animals simultaneously with, or within a few days before or after treatment with or exposure to, cholinesterase-inhibiting drugs, pesticides...

21 CFR 520.1631 - Oxfendazole and trichlorfon paste.

Code of Federal Regulations, 2013 CFR

2013-04-01

.... Trichlorfon is a cholinesterase inhibitor. Do not use this product in animals simultaneously with, or within a few days before or after treatment with or exposure to, cholinesterase-inhibiting drugs, pesticides...

21 CFR 520.1631 - Oxfendazole and trichlorfon paste.

Code of Federal Regulations, 2012 CFR

2012-04-01

.... Trichlorfon is a cholinesterase inhibitor. Do not use this product in animals simultaneously with, or within a few days before or after treatment with or exposure to, cholinesterase-inhibiting drugs, pesticides...

21 CFR 862.3240 - Cholinesterase test system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... is present at nerve endings and in erythrocytes (red blood cells) but is not present in plasma. Pseudo cholinesterase is present in plasma and liver but is not present in erythrocytes. Measurements...

21 CFR 862.3240 - Cholinesterase test system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... is present at nerve endings and in erythrocytes (red blood cells) but is not present in plasma. Pseudo cholinesterase is present in plasma and liver but is not present in erythrocytes. Measurements...

21 CFR 862.3240 - Cholinesterase test system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... is present at nerve endings and in erythrocytes (red blood cells) but is not present in plasma. Pseudo cholinesterase is present in plasma and liver but is not present in erythrocytes. Measurements...

21 CFR 862.3240 - Cholinesterase test system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... is present at nerve endings and in erythrocytes (red blood cells) but is not present in plasma. Pseudo cholinesterase is present in plasma and liver but is not present in erythrocytes. Measurements...

21 CFR 862.3240 - Cholinesterase test system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... is present at nerve endings and in erythrocytes (red blood cells) but is not present in plasma. Pseudo cholinesterase is present in plasma and liver but is not present in erythrocytes. Measurements...

The toxicologic effects of the carbamate insecticide aldicarb in mammals: a review.

PubMed Central

Risher, J F; Mink, F L; Stara, J F

1987-01-01

Aldicarb, 2-methyl-2-(methylthio)propionaldehyde-O-methylcarbamoyloxime, is an oxime carbamate insecticide manufactured by the Union Carbide Corporation and sold under the trade name Temik. It is a soil-applied systemic pesticide used against certain insects, mites, and nematodes, and is applied below the soil surface for absorption by plant roots. It is generally applied to the soil in the form of 5, 10, or 15% granules, and soil moisture is essential for the release of the toxicant. Uptake by plants is rapid. Aldicarb is currently registered for use on cotton, sugar beets, sugar cane (Louisiana only), potatoes, sweet potatoes, peanuts, oranges, pecans (Southeast only), dry beans, soybeans, and ornamental plants. Home and garden use is not permitted. Discovery of aldicarb and its oxidative sulfoxide and sulfone metabolites in well or ground water in Florida, Wisconsin, and New York, and accidental poisonings from ingesting contaminated watermelons and cucumbers in the South and West have spurred interest and concern about this pesticide. The primary mechanism of toxic action of aldicarb is cholinesterase inhibition. However, unlike the relatively irreversible anticholinesterase activity of the organophosphate pesticides, the carbamylation process which produces the anti-AChE action is quickly reversible. Aldicarb is readily absorbed through both the gut and the skin, but is rapidly metabolized and excreted in the urine almost completely within 24 hr. Although it is acutely toxic to humans and laboratory animals, aldicarb is not known to be carcinogenic, teratogenic, conclusively mutagenic, or to produce other long-term adverse health effects. In cases of accidental poisoning, the cholinergic symptoms have generally subsided within 6 hr, with no side effects or complications. PMID:3304999

Differences between organophosphorus insecticides in human self-poisoning: a prospective cohort study.

PubMed

Eddleston, Michael; Eyer, Peter; Worek, Franz; Mohamed, Fahim; Senarathna, Lalith; von Meyer, Ludwig; Juszczak, Edmund; Hittarage, Ariyasena; Azhar, Shifa; Dissanayake, Wasantha; Sheriff, M H Rezvi; Szinicz, Ladislaus; Dawson, Andrew H; Buckley, Nick A

Although more than 100 organophosphorus insecticides exist, organophosphorus poisoning is usually regarded as a single entity, distinguished only by the compound's lethal dose in animals. We aimed to determine whether the three most common organophosphorus insecticides used for self-poisoning in Sri Lanka differ in the clinical features and severity of poisoning they cause. We prospectively studied 802 patients with chlorpyrifos, dimethoate, or fenthion self-poisoning admitted to three hospitals. Blood cholinesterase activity and insecticide concentration were measured to determine the compound and the patients' response to insecticide and therapy. We recorded clinical outcomes for each patient. Compared with chlorpyrifos (35 of 439, 8.0%), the proportion dying was significantly higher with dimethoate (61 of 264, 23.1%, odds ratio [OR] 3.5, 95% CI 2.2-5.4) or fenthion (16 of 99, 16.2%, OR 2.2, 1.2-4.2), as was the proportion requiring endotracheal intubation (66 of 439 for chlorpyrifos, 15.0%; 93 of 264 for dimethoate, 35.2%, OR 3.1, 2.1-4.4; 31 of 99 for fenthion, 31.3%, 2.6, 1.6-4.2). Dimethoate-poisoned patients died sooner than those ingesting other pesticides and often from hypotensive shock. Fenthion poisoning initially caused few symptoms but many patients subsequently required intubation. Acetylcholinesterase inhibited by fenthion or dimethoate responded poorly to pralidoxime treatment compared with chlorpyrifos-inhibited acetylcholinesterase. Organophosphorus insecticide poisoning is not a single entity, with substantial variability in clinical course, response to oximes, and outcome. Animal toxicity does not predict human toxicity since, although chlorpyrifos is generally the most toxic in rats, it is least toxic in people. Each organophosphorus insecticide should be considered as an individual poison and, consequently, patients might benefit from management protocols developed for particular organophosphorus insecticides.

21 CFR 520.1326a - Mebendazole and trichlorfon powder.

Code of Federal Regulations, 2013 CFR

2013-04-01

... mares in the last month of pregnancy. Trichlorofon is a cholinesterase inhibitor. Do not administer simultaneously or within a few days before or after treatment with, or exposure to, cholinesterase-inhibiting...

21 CFR 522.1155 - Imidocarb dipropionate sterile powder.

Code of Federal Regulations, 2013 CFR

2013-04-01

... cholinesterase inhibitor. Do not use this product simultaneously with or a few days before or after treatment with or exposure to cholinesterase-inhibiting drugs, pesticides, or chemicals. Do not use in horses...

21 CFR 520.1326a - Mebendazole and trichlorfon powder.

Code of Federal Regulations, 2011 CFR

2011-04-01

... mares in the last month of pregnancy. Trichlorofon is a cholinesterase inhibitor. Do not administer simultaneously or within a few days before or after treatment with, or exposure to, cholinesterase-inhibiting...

21 CFR 522.1155 - Imidocarb dipropionate sterile powder.

Code of Federal Regulations, 2012 CFR

2012-04-01

... cholinesterase inhibitor. Do not use this product simultaneously with or a few days before or after treatment with or exposure to cholinesterase-inhibiting drugs, pesticides, or chemicals. Do not use in horses...

21 CFR 522.1155 - Imidocarb dipropionate sterile powder.

Code of Federal Regulations, 2011 CFR

2011-04-01

... cholinesterase inhibitor. Do not use this product simultaneously with or a few days before or after treatment with or exposure to cholinesterase-inhibiting drugs, pesticides, or chemicals. Do not use in horses...

21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.

Code of Federal Regulations, 2013 CFR

2013-04-01

.... Labeling shall bear the following statements: The drug is a cholinesterase inhibitor. Do not use this..., neuromuscular depolarizing agents (e.g., succinylcholine) or to cholinesterase-inhibiting drugs, pesticides, or...

21 CFR 520.1326a - Mebendazole and trichlorfon powder.

Code of Federal Regulations, 2012 CFR

2012-04-01

... mares in the last month of pregnancy. Trichlorofon is a cholinesterase inhibitor. Do not administer simultaneously or within a few days before or after treatment with, or exposure to, cholinesterase-inhibiting...

75 FR 17712 - Malathion and Diquat Dibromide; Cancellation Order for Amendments to Terminate Uses

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-07

... suggested that high levels of exposure to cholinesterase inhibitors such as OP insecticides - may cause a state of permanent hypersensitivity to cholinesterase inhibitors. Nonetheless, the commenter supported...

21 CFR 520.1326b - Mebendazole and trichlorfon paste.

Code of Federal Regulations, 2013 CFR

2013-04-01

... age, or mares in the last month of pregnancy. Trichlorfon is a cholinesterase inhibitor. Do not administer simultaneously or within a few days before or after treatment with, or exposure to, cholinesterase...

[Derivatives of lupinin and epilupinin as ligands of various cholinesterases].

PubMed

Basova, N E; Kormilitsyn, B N; Rozengart, E V; Saakov, V S; Suvorov, A A

2012-01-01

Literature data have been summarized on interaction of cholinesterases of some mammals and arthropods with a group of isomer derivatives of alkaloid lupini and its epimer epilupinin. As substrates of cholinesterases of several mammals there are studied 8 acetates containing in their molecules the chinolysidin bicycle with different structure of N-alkyl radical, which showed certain elements of specificity of action. For 2 isomer esters that are derivatives of the protonated base of the lupinin and epilupinin structures, differences in their substrate characteristics were revealed. The polyenzyme analysis if anticholinesterase efficiency was performed for 30 organophosphorus inhibitors that are dialkoxyphosphorus derivatives of lupinin and epilupinin; as a result, quite a few peculiarities of their action depending on their structure were revealed. Several tested compounds turned out to act as specific inhibitors of cholinesterases of some mammals and arthropods.

A sensitive radioimmunoassay for fludrocortisone in human plasma

NASA Technical Reports Server (NTRS)

Mitsky, V. P.; Workman, R. J.; Nicholson, W. E.; Vernikos, J.; Robertson, R. M.; Robertson, D.

1994-01-01

Fludrocortisone has been a mainstay of therapy for orthostatic hypotension for many years. Clinical experience suggests that there exists a substantial interindividual variation in responsiveness to the drug. To assess this, we have developed an assay that permits measurement of the low concentrations of fludrocortisone found in human plasma. Fludrocortisone was detected by radioimmunoassay. A polyclonal rabbit antibody, raised against dexamethasone which cross-reacts strongly with fludrocortisone, was reacted with either standard or unknown samples in the presence of [125I]fludrocortisone-3-TyrNH2 (synthesized by coupling tyrosine amide to fludrocortisone-3-oxime and iodinating with chloramine T oxidation). The ED10, ED50, and ED80 were 0.34, 5.0, and 30 ng/mL of plasma, respectively. The cross reactivity with other 9-fluorinated steroids was found as follows: dexamethasone, 340%; betamethasone, 230%; and triamicinolone, 8%. To preclude an erroneous result, subjects who were pregnant or receiving any steroid medication were excluded from the study. The percent cross-reactivity with the main naturally occurring steroids was as follows: 11-desoxycortisol 3.2%, cortisol 1.1%, DOC 0.3%, pregnenolone 0.1%, corticosterone 0.06%, progesterone 0.05%, and aldosterone < 0.05%. The only compound with potential for interference, because of its high level in the circulation in the early morning, was cortisol.(ABSTRACT TRUNCATED AT 250 WORDS).

The toxic chemistry of methyl bromide.

PubMed

Bulathsinghala, A T; Shaw, I C

2014-01-01

Methyl bromide (MeBr) is a chemically reactive compound that has found use as a fire retardant and fumigant used for wood, soil, fruits and grains. Its use is banned in many countries because of its ozone-depleting properties. Despite this ban, the use of MeBr persists in some parts of the world (e.g. New Zealand) due to its important role in maintaining strict biosecurity of exported and imported products. Its high chemical reactivity leads to a broad toxicological profile ranging from acute respiratory toxicity following inhalation exposure, through carcinogenicity to neurotoxicty. In this article, we discuss the chemistry of MeBr in the context of its mechanisms of toxicity. The chemical reactivity of MeBr clearly underlies its toxicity. Bromine (Br) is electronegative and a good leaving group; the δ+ carbon thus facilitates electrophilic methylation of biological molecules including glutathione (GSH) via its δ- sulphur atom, leading to downstream effects due to GSH depletion. DNA alkylation, either directly by MeBr or indirectly due to reduction in GSH-mediated detoxification of reactive alkylating chemical species, might explain the carcinogenicity of MeBr. The neurotoxicity of MeBr is much more difficult to understand, but we speculate that methyl phosphates formed in cells might contribute to its neurone-specific toxicity via cholinesterase inhibition. Finally, evidence reviewed shows that it is unlikely for Br⁻ liberated by the metabolism of MeBr to have any toxicological effect because the Br⁻ dose is very low.

Crystal Structure of the Extracellular Cholinesterase-Like Domain from Neuroligin-2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koehnke,J.; Jin, X.; Budreck, E.

Neuroligins (NLs) are catalytically inactive members of a family of cholinesterase-like transmembrane proteins that mediate cell adhesion at neuronal synapses. Postsynaptic neuroligins engage in Ca2+-dependent transsynaptic interactions via their extracellular cholinesterase domain with presynaptic neurexins (NRXs). These interactions may be regulated by two short splice insertions (termed A and B) in the NL cholinesterase domain. Here, we present the 3.3- Angstroms crystal structure of the ectodomain from NL2 containing splice insertion A (NL2A). The overall structure of NL2A resembles that of cholinesterases, but several structural features are unique to the NL proteins. First, structural elements surrounding the esterase active-site regionmore » differ significantly between active esterases and NL2A. On the opposite surface of the NL2A molecule, the positions of the A and B splice insertions identify a candidate NRX interaction site of the NL protein. Finally, sequence comparisons of NL isoforms allow for mapping the location of residues of previously identified mutations in NL3 and NL4 found in patients with autism spectrum disorders. Overall, the NL2 structure promises to provide a valuable model for dissecting NL isoform- and synapse-specific functions.« less

Crystal structure of the extracellular cholinesterase-like domain from neuroligin-2

PubMed Central

Koehnke, Jesko; Jin, Xiangshu; Budreck, Elaine C.; Posy, Shoshana; Scheiffele, Peter; Honig, Barry; Shapiro, Lawrence

2008-01-01

Neuroligins (NLs) are catalytically inactive members of a family of cholinesterase-like transmembrane proteins that mediate cell adhesion at neuronal synapses. Postsynaptic neuroligins engage in Ca2+-dependent transsynaptic interactions via their extracellular cholinesterase domain with presynaptic neurexins (NRXs). These interactions may be regulated by two short splice insertions (termed A and B) in the NL cholinesterase domain. Here, we present the 3.3-Å crystal structure of the ectodomain from NL2 containing splice insertion A (NL2A). The overall structure of NL2A resembles that of cholinesterases, but several structural features are unique to the NL proteins. First, structural elements surrounding the esterase active-site region differ significantly between active esterases and NL2A. On the opposite surface of the NL2A molecule, the positions of the A and B splice insertions identify a candidate NRX interaction site of the NL protein. Finally, sequence comparisons of NL isoforms allow for mapping the location of residues of previously identified mutations in NL3 and NL4 found in patients with autism spectrum disorders. Overall, the NL2 structure promises to provide a valuable model for dissecting NL isoform- and synapse-specific functions. PMID:18250328

The significance of low substrate concentration measurements for mechanistic interpretation in cholinesterases.

PubMed

Stojan, Jure

2013-03-25

Cholinesterases do not follow the Michaelis-Menten kinetics. In the past, many reaction schemes were suggested to explain their complex interactions during the substrate turnover. Covalent catalysis was recognized very early and therefore, double intermediate traditional reaction scheme for the hydrolysis of good substrates at low concentrations was postulated. However, at intermediate and high substrate concentrations homotropic pseudocooperative effects take place in all cholinesterases, due to the nature of their buried active center. In this study, the significance and usefulness of experimental data obtained at low substrate concentrations, where only one substrate molecule accesses the active site at a time, are to be specified for the overall mechanistic evaluations. Indeed, different interpretations are expected when data are processed with equations derived from different reaction schemes. Consequently, the scheme with two substrate binding sites which comprises the structurally evidenced fully occupied active site as ultimate cause for substantially decreased cholinesterase activity at extremely high substrate concentrations is considered here. A special emphasis is put on butyrylcholinesterase, the enzyme with the largest active site among cholinesterases, where the pseudocooperative effects appear at much higher concentrations than in acetylcholinesterases. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

MEASURING CHOLINESTERASE ACTIVITY IN HUMAN STUDIES.

EPA Science Inventory

Biomonitoring of organophosphorous and carbamate pesticides has focused primarily on the inhibition of blood cholinesterase. Blood biomonitoring, however, can be invasive, time-consuming, and costly, especially in young children and infants. Therefore, saliva biomonitoring ha...

21 CFR 522.1156 - Imidocarb dipropionate solution.

Code of Federal Regulations, 2013 CFR

2013-04-01

... intravenous use. Repeat the dose after 2 weeks for a total of two treatments. Imidocarb is a cholinesterase... cholinesterase-inhibiting drugs, pesticides, or chemicals. Federal law restricts this drug to use by or on the...

40 CFR 161.34 - Flagging of studies for potential adverse effects.

Code of Federal Regulations, 2012 CFR

2012-07-01

... feeding study or combined chronic feeding/oncogenicity study 83-1 Cholinesterase inhibition NOEL less than... ADI 9 Subchronic feeding study 82-1 Cholinesterase inhibition NOEL less than 100 times the current...

21 CFR 522.1156 - Imidocarb dipropionate solution.

Code of Federal Regulations, 2012 CFR

2012-04-01

... intravenous use. Repeat the dose after 2 weeks for a total of two treatments. Imidocarb is a cholinesterase... cholinesterase-inhibiting drugs, pesticides, or chemicals. Federal law restricts this drug to use by or on the...

40 CFR 161.34 - Flagging of studies for potential adverse effects.

Code of Federal Regulations, 2013 CFR

2013-07-01

... feeding study or combined chronic feeding/oncogenicity study 83-1 Cholinesterase inhibition NOEL less than... ADI 9 Subchronic feeding study 82-1 Cholinesterase inhibition NOEL less than 100 times the current...

Functionalized nanoparticles for AMF-induced gene and drug delivery

NASA Astrophysics Data System (ADS)

Biswas, Souvik

The properties and broad applications of nano-magnetic colloids have generated much interest in recent years. Specially, Fe3O4 nanoparticles have attracted a great deal of attention since their magnetic properties can be used for hyperthermia treatment or drug targeting. For example, enhanced levels of intracellular gene delivery can be achieved using Fe3O4 nano-vectors in the presence of an external magnetic field, a process known as 'magnetofection'. The low cytotoxicity, tunable particle size, ease of surface functionalization, and ability to generate thermal energy using an external alternating magnetic field (AMF) are properties have propelled Fe3O4 research to the forefront of nanoparticle research. The strategy of nanoparticle-mediated, AMF-induced heat generation has been used to effect intracellular hyperthermia. One application of this 'magnetic hyperthermia' is heat activated local delivery of a therapeutic effector (e.g.; drug or polynucleotide). This thesis describes the development of a magnetic nano-vector for AMF-induced, heat-activated pDNA and small molecule delivery. The use of heat-inducible vectors, such as heat shock protein ( hsp) genes, is a promising mode of gene therapy that would restrict gene expression to a local region by focusing a heat stimulus only at a target region. We thus aimed to design an Fe3O4 nanoparticle-mediated gene transfer vehicle for AMF-induced localized gene expression. We opted to use 'click' oximation techniques to assemble the magnetic gene transfer vector. Chapter 2 describes the synthesis, characterization, and transfection studies of the oxime ether lipid-based nano-magnetic vectors MLP and dMLP. The synthesis and characterization of a novel series of quaternary ammonium aminooxy reagents (2.1--2.4) is described. These cationic aminooxy compounds were loaded onto nanoparticles for ligation with carbonyl groups and also to impart a net positive charge on the nanoparticle surface. Our studies indicated that the non-toxic magnetoplexes (magnetic nanoparticle + pDNA complex) derived from dMLP deliver pDNA into mammalian cells even without external magnetic assistance. To date, dMLP is the only polymer-free magnetic gene delivery system that can deliver pDNA without any magnetic assistance. Chapter 3 of this thesis outlines the synthesis and characterization of other oxime ether lipids and details studies using derived-lipoplexes. These lipids were evaluated in pDNA and siRNA transfection studies in various mammalian cell lines. This work constitutes the first use of an oxime ether as the linking domain in cationic transfection lipids. These biocompatible oxime ether lipids can be readily assembled by click chemistry through ligation of hydrophobic aldehydes with quaternary ammonium aminooxy salts. Our studies showed that the oxime ether lipids transfected pDNA and siRNA efficiently in MCF-7, H 1792, and in PAR C10 cells comparable to and in some cases better than commercial transfection lipids. Chapter 4 describes the design and characterization of a nano-magnetic delivery system for AMF-induced drug (doxorubicin) release. In efforts to develop a magnetic formulation free from thermosensitive materials, such as hydrogels, we synthesized three nanoparticle-based doxorubicin formulations using charge interactions as the key associative force. To do so, we synthesized and characterized a novel cationic oxime ether conjugate at C-13 of doxorubicin. Our investigation indicated that the positive charge of the oxime ether drug conjugate tended to bind better to the negatively charged nanoparticle than did the other formulations prepared in stepwise manner. Our findings show that the nano-magnetic formulations remained essestially inactive at body temperature (37.5 °C) and released a majority of the cargo only when exposed to an external AMF. Our designed magnetic drug delivery platform is the first example of an AMF-inducible system that does not depend on the inclusion of thermosensitive materials. Finally, we have developed a bioanalytical application of the highly chemoselective oximation chemistry using aminooxy reagent 2.1. Chapter 5 describes a silica microchip containing micropillars coated with cationic aminooxy reagent 2.1. The microchip captures gaseous ketones and aldehydes from exhaled human breath. A brief description of microchip fabricated breath analyzer and breath analysis is described in Chapter 5. Our studies showed that the acetone capture efficiency of the aminooxy-loaded microchip was 98%.

Early effects of whole body irradiation on cholinesterase activity in guinea-pigs' blood, with special regard to radiation sickness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lundin, J; Clemedson, C -J; Nelson, A

1957-07-01

Male guinea-pigs suffered a loss of cholinesterase activity in plasma amounting to about 30% during the first two days after whole-body roentgen irradiation with 400 r. No changes in the activity of acetylcholinesterase in erythrocytes to be ascribed to the irradiation could be demonstrated during the first two days. A routine method for determination of the cholinesterase activities has been tested but is found less suitable as a diagnostic tool for the early recognition of the effects of irradiation.

Structural insights into cholinesterases inhibition by harmane β-carbolinium derivatives: a kinetics-molecular modeling approach.

PubMed

Torres, Juliana M; Lira, Aline F; Silva, Daniel R; Guzzo, Lucas M; Sant'Anna, Carlos M R; Kümmerle, Arthur E; Rumjanek, Victor M

2012-09-01

The natural indole alkaloids, the β-carbolines, are often associated with cholinesterase inhibition, especially their quaternary salts, which frequently have higher activity than the free bases. Due to lack of information explaining this fact in the literature, the cholinesterase inhibition by the natural product harmane and its two β-carbolinium synthetic derivative salts (N-methyl and N-ethyl) was explored, together with a combination of kinetics and a molecular modeling approach. The results, mainly for the β-carbolinium salts, demonstrated a noncompetitive inhibition profile, ruling out previous findings which associated cholinesterase inhibition by β-carbolinium salts to a possible mimicking of the choline moiety of the natural substrate, acetylcholine. Molecular modeling studies corroborate this kind of inhibition through analyses of inhibitor/enzyme and inhibitor/substrate/enzyme complexes of both enzymes. Copyright © 2012 Elsevier Ltd. All rights reserved.

Genomic clones for human cholinesterase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kott, M.; Venta, P.J.; Larsen, J.

1987-05-01

A human genomic library was prepared from peripheral white blood cells from a single donor by inserting an MboI partial digest into BamHI poly-linker sites of EMBL3. This library was screened using an oligolabeled human cholinesterase cDNA probe over 700 bp long. The latter probe was obtained from a human basal ganglia cDNA library. Of approximately 2 million clones screened with high stringency conditions several positive clones were identified; two have been plaque purified. One of these clones has been partially mapped using restriction enzymes known to cut within the coded region of the cDNA for human serum cholinesterase. Hybridizationmore » of the fragments and their sizes are as expected if the genomic clone is cholinesterase. Sequencing of the DNA fragments in M13 is in progress to verify the identify of the clone and the location of introns.« less

Studies on combined effects of organophosphates or carbamates and morsodren in birds. II. Plasma and cholinesterase in quail fed morsodren and orally dosed with parathion or carbofuran

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dieter, M.P.; Ludke, J.L.

1978-04-01

The degree of interaction between mercury and cholinesterase inhibiting pesticides was determined by comparing enzyme responses to sublethal dosages of parathion or carbofuran in quail fed 0.05, 0.5, or 5.0 ppM morsodren for 18 weeks. A statistically significant interaction was defined as greater brain cholinesterase inhibition in morsodren-fed than in clean-fed birds following pesticide dosage. The tissue residues of mercury that accumulated before significant mercury-parathion interactions occurred were higher than levels that might be expected in natural populations, but significant mercury-carbofuran interactions occurred in birds that had only accumulated 1.0 ppM liver mercury. The results indicate that indiscriminate usage ofmore » cholinesterase inhibiting pesticides is dangerous, since natural populations of fish-eating birds oftentimes contain this magnitude of mercury.« less

Isolation and reconstitution of cytochrome P450ox and in vitro reconstitution of the entire biosynthetic pathway of the cyanogenic glucoside dhurrin from sorghum.

PubMed Central

Kahn, R A; Bak, S; Svendsen, I; Halkier, B A; Møller, B L

1997-01-01

A cytochrome P450, designated P450ox, that catalyzes the conversion of (Z)-p-hydroxyphenylacetaldoxime (oxime) to p-hydroxymandelonitrile in the biosynthesis of the cyanogenic glucoside beta-D-glucopyranosyloxy-(S)-p-hydroxymandelonitrile (dhurrin), has been isolated from microsomes prepared from etiolated seedlings of sorghum (Sorghum bicolor L. Moench). P450ox was solubilized using nonionic detergents, and isolated by ion-exchange chromatography, Triton X-114 phase partitioning, and dye-column chromatography. P450ox has an apparent molecular mass of 55 kD, its N-terminal amino acid sequence is -ATTATPQLLGGSVP, and it contains the internal sequence MDRLVADLDRAAA. Reconstitution of P450ox with NADPH-P450 oxidoreductase in micelles of L-alpha-dilauroyl phosphatidylcholine identified P450ox as a multifunctional P450 catalyzing dehydration of (Z)-oxime to p-hydroxyphenylaceto-nitrile (nitrile) and C-hydroxylation of p-hydroxyphenylacetonitrile to nitrile. P450ox is extremely labile compared with the P450s previously isolated from sorghum. When P450ox is reconstituted in the presence of a soluble uridine diphosphate glucose glucosyltransferase, oxime is converted to dhurrin. In vitro reconstitution of the entire dhurrin biosynthetic pathway from tyrosine was accomplished by the insertion of CYP79 (tyrosine N-hydroxylase), P450ox, and NADPH-P450 oxidoreductase in lipid micelles in the presence of uridine diphosphate glucose glucosyltransferase. The catalysis of the conversion of Tyr into nitrile by two multifunctional P450s explains why all intermediates in this pathway except (Z)-oxime are channeled. PMID:9414567

Effects of biological and technical factors on brain and muscle cholinesterases in Nile tilapia, Oreochromis niloticus: implications for biomonitoring neurotoxic contaminations.

PubMed

Pathiratne, A; Chandrasekera, L W H U; De Seram, P K C

2008-02-01

Influence of body length, body weight, gender, sexual maturity, and tissue storage on brain and muscle cholinesterases (ChE) in Nile tilapia was evaluated considering its potential use in biomonitoring neurotoxic contaminations in tropical environments. Results show that ChE activities in both tissues decreased significantly with increased total length (4-24.5 cm) or body weight (1-186 g) of the fish and the relationships were curvilinear. Comparisons of the slopes and elevations of the regression lines of the logarithmic ChE and body size relationships of males with those of females indicated that gender had no significant effect on the body size-specific ChE activities. Response of the ChE of sexually mature males to chlorpyrifos exposure was similar to that of females. Gonadal maturity stage of this fish does not seem to influence ChE activities. Storage of tissues at -80 degrees C for 28 days had no significant effect on ChE activities in the control fish and the fish exposed to carbofuran. However, a partial reactivation of brain ChE activities was observed in the fish exposed to carbosulfan after 28 days of storage. The results emphasize the importance of consideration of body size of the fish and storage time of the tissues in order to formulate accurate conclusions about the neurotoxic chemical exposure when ChE of the fish is used in biomonitoring programs.

Utilization of Nitrophenylphosphates and Oxime-Based Ligation for the Development of Nanomolar Affinity Inhibitors of the Yersinia Pestis Outer Protein H (YopH) Phosphatase†, §, ¶

PubMed Central

Bahta, Medhanit; Lountos, George T.; Dyas, Beverly; Kim, Sung-Eun; Ulrich, Robert G.; Waugh, David S.; Burke, Terrence R.

2011-01-01

Our current study reports the first KM optimization of a library of nitrophenylphosphate-containing substrates for generating an inhibitor lead against the Yersinia pestis outer protein phosphatase (YopH). A high activity substrate identified by this method (KM = 80 μM was converted from a substrate into an inhibitor by replacement of its phosphate group with difluoromethylphosphonic acid and by attachment of an aminooxy handle for further structural optimization by oxime-ligation. A co-crystal structure of this aminooxy-containing platform in complex with YopH allowed the identification of a conserved water molecule proximal to the aminooxy group that was subsequently employed for the design of furanyl-based oxime derivatives. By this process, a potent (IC50 = 190 nM) and non-promiscuous inhibitor was developed with good YopH selectivity relative to a panel of phosphatases. The inhibitor showed significant inhibition of intracellular Y. pestis replication at a non-cytotoxic concentration. The current work presents general approaches to PTP inhibitor development that may be useful beyond YopH. PMID:21443195

Syntheses, crystal structures and characterization of nitrogen-rich salts based on bis (1H-tetrazol-5-yl) methanone oxime

NASA Astrophysics Data System (ADS)

Lin, Xinyu; Guo, Weiming; Zhang, Tianhe; Huang, Jingru; Tong, Yi; Zhang, Tonglai

2017-08-01

Two nitrogen-rich energetic salts (NH4)2(bto) (1) and (NH3OH)2(bto)·H2O (2) [H2bto = Bis (1H-tetrazol-5-yl) methanone oxime] were synthesized by an improved method in which water was used as solvent. These compounds were characterized by FT-IR spectroscopy, elemental analysis and single crystal X-ray diffraction. Their crystal structures were confirmed to belong to monoclinic system with space group P21 for 1 and Pc for 2, respectively. The detailed thermal behaviours were investigated by using differential scanning calorimetry (DSC) and thermogravimetric method (TG) (decomposition temperature >250 °C). The enthalpies of formation were calculated through the experimental values of combustion enthalpy. In addition, the sensitivities toward impact and friction were tested with standard methods, and those results indicated that two compounds are all insensitive (impact >40 J and friction >360 N). In short, both of the compounds show potential usages as energetic materials. The improved process opens a door for exploring nitrogen-rich salts based on Bis (1H-tetrazol-5-yl) methanone oxime.

Determination of Carbonyl Functional Groups in Bio-oils by Potentiometric Titration: The Faix Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Black, Stuart; Ferrell, Jack R.

We know that carbonyl compounds, present in bio-oils, are responsible for bio-oil property changes upon storage and during upgrading. Specifically, carbonyls cause an increase in viscosity (often referred to as 'aging') during storage of bio-oils. As such, carbonyl content has previously been used as a method of tracking bio-oil aging and condensation reactions with less variability than viscosity measurements. In addition, carbonyls are also responsible for coke formation in bio-oil upgrading processes. Given the importance of carbonyls in bio-oils, accurate analytical methods for their quantification are very important for the bio-oil community. Potentiometric titration methods based on carbonyl oximation havemore » long been used for the determination of carbonyl content in pyrolysis bio-oils. Here, we present a modification of the traditional carbonyl oximation procedures that results in less reaction time, smaller sample size, higher precision, and more accurate carbonyl determinations. And while traditional carbonyl oximation methods occur at room temperature, the Faix method presented here occurs at an elevated temperature of 80 degrees C.« less

Design and Biological Evaluation of Antifouling Dihydrostilbene Oxime Hybrids.

PubMed

Moodie, Lindon W K; Cervin, Gunnar; Trepos, Rozenn; Labriere, Christophe; Hellio, Claire; Pavia, Henrik; Svenson, Johan

2018-04-01

By combining the recently reported repelling natural dihydrostilbene scaffold with an oxime moiety found in many marine antifoulants, a library of nine antifouling hybrid compounds was developed and biologically evaluated. The prepared compounds were shown to display a low antifouling effect against marine bacteria but a high potency against the attachment and growth of microalgae down to MIC values of 0.01 μg/mL for the most potent hybrid. The mode of action can be characterized as repelling via a reversible non-toxic biostatic mechanism. Barnacle cyprid larval settlement was also inhibited at low μg/mL concentrations with low levels or no toxicity observed. Several of the prepared compounds performed better than many reported antifouling marine natural products. While several of the prepared compounds are highly active as antifoulants, no apparent synergy is observed by incorporating the oxime functionality into the dihydrostilbene scaffold. This observation is discussed in light of recently reported literature data on related marine natural antifoulants and antifouling hybrids as a potentially general strategy for generation of improved antifoulants.

Divergent and convergent synthesis of GalNAc-conjugated dendrimers using dual orthogonal ligations.

PubMed

Thomas, Baptiste; Pifferi, Carlo; Daskhan, Gour Chand; Fiore, Michele; Berthet, Nathalie; Renaudet, Olivier

2015-12-21

The synthesis of glycodendrimers remains a challenging task. In this paper we propose a protocol based on both oxime ligation (OL) to combine cyclopeptide repeating units as the dendritic core and the copper(i)-catalyzed azide-alkyne cycloaddition (CuAAC) to conjugate peripheral α and β propargylated GalNAc. By contrast with the oxime-based iterative protocol reported in our group, our current strategy can be used in both divergent and convergent routes with similar efficiency and the resulting hexadecavalent glycodendrimers can be easily characterized compared to oxime-linked analogues. A series of glycoconjugates displaying four or sixteen copies of both α and β GalNAc have been prepared and their ability to inhibit the adhesion of the soybean agglutinin (SBA) lectin to polymeric-GalNAc immobilized on microtiter plates has been evaluated. As was anticipated, the higher inhibitory effect (IC50 = 0.46 μM) was measured with the structure displaying αGalNAc with the higher valency (compound 13), which demonstrates that the binding properties of these glycoconjugates are strongly dependent on the orientation and distribution of the GalNAc units.

Synthesis and mechanistic studies of curcumin analog-based oximes as potential anticancer agents.

PubMed

Qin, Hua-Li; Leng, Jing; Youssif, Bahaa G M; Amjad, Muhammad Wahab; Raja, Maria Abdul Ghafoor; Hussain, Muhammad Ajaz; Hussain, Zahid; Kazmi, Syeda Naveed; Bukhari, Syed Nasir Abbas

2017-09-01

The incidence of cancer can be decreased by chemoprevention using either natural or synthetic agents. Apart from synthetic compounds, numerous natural products have exhibited promising potential to inhibit carcinogenesis in vivo. In this study, α, β-unsaturated carbonyl-based anticancer compounds were used as starting materials to synthesize new oxime analogs. The findings from the antiproliferative assay using seven different human cancer cell lines provided a clear picture of structure-activity relationship. The oxime analogs namely 7a and 8a showed strong antiproliferative activity against the cell lines. The mechanistic effects of compounds on EGFR-TK kinases and tubulin polymerization and BRAF V 600E were investigated. In addition, the efficacy of compounds in reversing the efflux-mediated resistance developed by cancer cells was also studied. The compounds 5a and 6a displayed potent activity on various targets such as BRAF V 600E and EGFR-TK kinases and also exhibited strong antiproliferative activity against different cell lines hence showing potential of multifunctional anticancer agents. © 2017 John Wiley & Sons A/S.

Determination of Carbonyl Functional Groups in Bio-oils by Potentiometric Titration: The Faix Method

DOE PAGES

Black, Stuart; Ferrell, Jack R.

2017-02-07

We know that carbonyl compounds, present in bio-oils, are responsible for bio-oil property changes upon storage and during upgrading. Specifically, carbonyls cause an increase in viscosity (often referred to as 'aging') during storage of bio-oils. As such, carbonyl content has previously been used as a method of tracking bio-oil aging and condensation reactions with less variability than viscosity measurements. In addition, carbonyls are also responsible for coke formation in bio-oil upgrading processes. Given the importance of carbonyls in bio-oils, accurate analytical methods for their quantification are very important for the bio-oil community. Potentiometric titration methods based on carbonyl oximation havemore » long been used for the determination of carbonyl content in pyrolysis bio-oils. Here, we present a modification of the traditional carbonyl oximation procedures that results in less reaction time, smaller sample size, higher precision, and more accurate carbonyl determinations. And while traditional carbonyl oximation methods occur at room temperature, the Faix method presented here occurs at an elevated temperature of 80 degrees C.« less

A comparison of serum cholinesterase methods : II.

DOT National Transportation Integrated Search

1972-03-01

Among aerial applicator personnek, the primary value of the periodic blood cholinesterase (ChE) assays is the detection of pesticide poisoning indicated by a decrease in the enzyme activity since the previous (or pre-season) assay. Comparison of thes...

SAR by Oxime-Containing Peptide Libraries: Application to Tsg101 Ligand Optimization

PubMed Central

Liu, Fa; Stephen, Andrew G.; Waheed, Abdul A.; Aman, M. Javad; Freed, Eric O.; Fisher, Robert J.; Burke, Terrence R.

2008-01-01

HIV-1 viral assembly requires a direct interaction between a Pro-Thr-Ala-Pro (“PTAP”) motif in the viral protein Gag-p6 and the cellular endosomal sorting factor Tsg101. In an effort to develop competitive inhibitors of this interaction, an SAR study was conducted based on the application of post solid-phase oxime formation involving the sequential insertion of aminooxy-containing residues within a nonamer parent peptide followed by reaction with libraries of aldehydes. Approximately 15–20-fold enhancement in binding affinity was achieved by this approach. PMID:18655064

Application of oxime-diversification to optimize ligand interactions within a cryptic pocket of the polo-like kinase 1 polo-box domain.

PubMed

Zhao, Xue Zhi; Hymel, David; Burke, Terrence R

2016-10-15

By a process involving initial screening of a set of 87 aldehydes using an oxime ligation-based strategy, we were able to achieve a several-fold affinity enhancement over one of the most potent previously known polo-like kinase 1 (Plk1) polo-box domain (PBD) binding inhibitors. This improved binding may result by accessing a newly identified auxiliary region proximal to a key hydrophobic cryptic pocket on the surface of the protein. Our findings could have general applicability to the design of PBD-binding antagonists. Published by Elsevier Ltd.

Visible-light-promoted and one-pot synthesis of phenanthridines and quinolines from aldehydes and O-acyl hydroxylamine.

PubMed

An, Xiao-De; Yu, Shouyun

2015-06-05

A one-pot synthesis of phenanthridines and quinolines from commercially available or easily prepared aldehydes has been reported. O-(4-Cyanobenzoyl)hydroxylamine was utilized as the nitrogen source to generate O-acyl oximes in situ with aldehydes catalyzed by Brønsted acid. O-Acyl oximes were then subjected to visible light photoredox catalyzed cyclization via iminyl radicals to furnish aza-arenes. A variety of phenanthridines and quinolines have been prepared assisted by Brønsted acid and photocatalyst under visible light at room temperature with satisfactory yields.

Computational investigations of trans-platinum(II) oxime complexes used as anticancer drug

NASA Astrophysics Data System (ADS)

Sayin, Koray; Karakaş, Duran

2018-01-01

Some platinum oxime complexes are optimized at HF/CEP-31G level which has been reported as the best level for these type complexes in the gas phase. IR spectrum is calculated and the new scale factor is derived. NMR spectrum is calculated at the same level of theory and examined in detail. Quantum chemical parameters which have been mainly used are investigated and their formulas are given in detail. Additionally, selected quantum chemical parameters of studied complexes are calculated. New theoretical IC50% formulas are derived and biological activity rankings of mentioned complexes are investigated.

Surface-Electrochemical Sensor for the Measurement of Anti-Cholinesterase Activity

NASA Astrophysics Data System (ADS)

Matsuura, Hiroaki; Sato, Yukari; Yabuki, Soichi; Sawaguchi, Takahiro; Mizutani, Fumio

An organophosphorus pesticide, ethylthiometon (0.01-0.2 ppm) was determined by using a surface-electrochemical sensor system: the monolayer formation (chemisorption)-reductive desorption of thiocholine was applied to monitor the activity change of cholinesterase caused by the pesticide.

Synthesis, characterization and biological screening of sulfonamides derived form 2-phenylethylamine.

PubMed

Rehman, Aziz-ur; Afroz, Sumbel; Abbasi, Muhammad Athar; Tanveer, Wajeeha; Khan, Khalid Mohammed; Ashraf, Muhammad; Ahmad, Irshad; Afzal, Iftikhar; Ambreen, Nida

2012-10-01

In the present study, a series of N-substituted derivatives of 2-phenylethylamine has been synthesized. The reaction of 2-phenylethylamine (1) with benzene sulfonyl chloride (2) yielded N-(2-phenylethyl) benzenesulfonamide (3), which further on treatment with alkyl/acyl halides (4a-i) in the presence of sodium hydride furnished into N-substituted sulfonamides (5a-i). These derivatives were characterized by IR, (1)H-NMR and EI-MS and then screened against acetyl cholinesterase (AChE), butyryl cholinesterase (BChE) and lipoxygenase enzyme (LOX) and were found to be potent inhibitors of butyryl cholinesterase only.

A left lateral accessory pathway unmasked by rivastigmine.

PubMed

Guenancia, Charles; Fichot, Marie; Garnier, Fabien; Montoy, Mathieu; Laurent, Gabriel

A 75-year-old woman was referred for advice regarding surface electrocardiographic modifications after the initiation of rivastigmine. In our patient, the baseline ECGs appeared perfectly normal. However, the initiation of a cholinesterase inhibitor unmasked a left lateral accessory pathway that had never been diagnosed before. Although cholinesterase inhibitors are known to increase vagal tone, the PR interval was shortened after rivastigmine administration, thus excluding this hypothesis to explain the appearance of the accessory pathway. Therefore, we hypothesized that cholinesterase inhibitors may have increased conduction velocity in the accessory pathway or in the atria. Copyright © 2017 Elsevier Inc. All rights reserved.

VARIATION IN CHOLINESTERASE ACTIVITY IN TISSUES OF RATS AT DIFFERENT TIMES AFTER IRRADIATION (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zubkova, S.R.; Chernavskaya, N.M.

1959-06-11

It was found that a single lethal dose (1000 r) changes the cholinesterase activity in the brain, liver, and blood serum. After 5 hr and 45 min the cholinesterase activity in tissues drops from the normal level (15.9% in blood serum, 20.6% in the brain, and 18.4% in the liver). After three days the activity changes in various tissues: in the liver it continues to drop, in the brain it rises but does not reach the standard level, and it increases sharply in the blood serum. (R.V.J.)

Acetylcholine-hydrolyzing activities in soluble brain fraction: Characterization with reversible and irreversible inhibitors.

PubMed

Estévez, Jorge; Selva, Verónica; Benabent, Mónica; Mangas, Iris; Sogorb, Miguel Ángel; Vilanova, Eugenio

2016-11-25

Some effects of organophosphorus compounds (OPs) esters cannot be explained through actions on currently recognized targets acetylcholinesterase or neuropathy target esterase (NTE). In soluble chicken brain fraction, three components (Eα, Eβ and Eγ) of pheny lvalerate esterase activity (PVase) were kinetically discriminated and their relationship with acetylcholine-hydrolyzing activity (cholinesterase activity) were studied in previous works. In this work, four enzymatic components (CS1, CS2, CS3 and CS4) of cholinesterase activity have been discriminated in soluble fraction, according to their sensitivity to irreversible inhibitors mipafox, paraoxon, PMSF and iso-OMPA and to reversible inhibitors ethopropazine and BW284C51. Cholinesterase component CS1 can be related to the Eα component of PVase activity and identified as butyrylcholinesterase (BuChE). No association and similarities can be stablished among the other PVase component (Eβ and Eγ) with the other cholinesterase components (CS2, CS3, CS4). The kinetic analysis has allowed us to stablish a method for discriminating the enzymatic component based on a simple test with two inhibitors. It can be used as biomarker in toxicological studies and for monitoring these cholinesterase components during isolation and molecular identification processes, which will allow OP toxicity to be understood by a multi-target approach. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Nature as a source of metabolites with cholinesterase-inhibitory activity: an approach to Alzheimer's disease treatment.

PubMed

Pinho, Brígida R; Ferreres, Federico; Valentão, Patrícia; Andrade, Paula B

2013-12-01

Alzheimer's disease (AD) is the most common cause of dementia, being responsible for high healthcare costs and familial hardships. Despite the efforts of researchers, no treatment able to delay or stop AD progress exists. Currently, the available treatments are only symptomatic, cholinesterase inhibitors being the most widely used drugs. Here we describe several natural compounds with anticholinesterase (acetylcholinesterase and butyrylcholinesterase) activity and also some synthetic compounds whose structures are based on those of natural compounds. Galantamine and rivastigmine are two cholinesterase inhibitors used in therapeutics: galantamine is a natural alkaloid that was extracted for the first time from Galanthus nivalis L., while rivastigmine is a synthetic alkaloid, the structure of which is modelled on that of natural physostigmine. Alkaloids include a high number of compounds with anticholinesterases activity at the submicromolar range. Quinones and stilbenes are less well studied regarding cholinesterase inhibition, although some of them, such as sargaquinoic acid or (+)-α-viniferin, show promising activity. Among flavonoids, flavones and isoflavones are the most potent compounds. Xanthones and monoterpenes are generally weak cholinesterase inhibitors. Nature is an almost endless source of bioactive compounds. Several natural compounds have anticholinesterase activity and others can be used as leader compounds for the synthesis of new drugs. © 2013 Royal Pharmaceutical Society.

Evolution of cholinesterases in the animal kingdom.

PubMed

Pezzementi, Leo; Chatonnet, Arnaud

2010-09-06

Cholinesterases emerged from a family of enzymes and proteins with adhesion properties. This family is absent in plants and expanded in multicellular animals. True cholinesterases appeared in triploblastic animals together with the cholinergic system. Lineage specific duplications resulted in two acetylcholinesterases in most hexapods and in up to four genes in nematodes. In vertebrates the duplication leading to acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) is now considered to be an ancient event which occurred before the split of osteichthyes. The product of one or the other of the paralogues is responsible for the physiological hydrolysis of acetylcholine, depending on the species lineage and tissue considered. The BChE gene seems to have been lost in some fish lineages. The complete genome of amphioxus (Branchiostoma floridae: cephalochordate) contains a large number of duplicated genes or pseudogenes of cholinesterases. Sequence comparison and tree constructions raise the question of considering the atypical ChE studied in this organism as a representative of ancient BChE. Thus nematodes, arthropods, annelids, molluscs, and vertebrates typically possess two paralogous genes coding for cholinesterases. The origin of the duplication(s) is discussed. The mode of attachment through alternative C-terminal coding exons seems to have evolved independently from the catalytic part of the gene. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

MEASURING CHOLINESTERASE ACTIVITY IN HUMAN SALIVA

EPA Science Inventory

To assess the potential for using saliva in pesticide biomonitoring, the consistency of cholinesterase activity in human saliva collected over time was examined. In this pilot study, saliva was collected from 20 healthy adults once per week for 5 consecutive weeks using 2 differe...

Age-related behavioral effects of methomyI in Brown Norway rats.

EPA Science Inventory

Methomyl is a cholinesterase-inhibiting carbamate pesticide that is used in the field on cotton and a variety of fruits and vegetables. Concerns have been raised generally about age-related differences in susceptibility to cholinesterase-inhibiting pesticides, especially for chil...

MEASURING CHOLINESTERASE ACTIVITY IN HUMAN SALIVA.

EPA Science Inventory

To assess the potential for using saliva in pesticide biomonitoring, the consistency of cholinesterase activity in human saliva collected over time was examined. In this pilot study, saliva was collected from 20 healthy adults once per week for 5 consecutive weeks using 2 differe...

Freeze-drying of HI-6-loaded recombinant human serum albumin nanoparticles for improved storage stability.

PubMed

Dadparvar, Miriam; Wagner, Sylvia; Wien, Sascha; Worek, Franz; von Briesen, Hagen; Kreuter, Jörg

2014-10-01

Severe intoxications with organophosphates require the immediate administration of atropine in combination with acetyl cholinesterase (AChE) reactivators such as HI-6. Although this therapy regimen enables the treatment of peripheral symptoms, the blood-brain barrier (BBB) restricts the access of the hydrophilic antidotes to the central nervous system which could lead to a fatal respiratory arrest. Therefore, HI-6-loaded albumin nanoparticles were previously developed to enhance the transport across this barrier and were able to reactivate organophosphate-(OP)-inhibited AChE in an in vitro BBB model. Since HI-6 is known to be moisture-sensitive, the feasibility of freeze-drying of the HI-6-loaded nanoparticles was investigated in the present study using different cryo- and lyoprotectants at different concentrations. Trehalose and sucrose (3%, w/v)-containing formulations were superior to mannitol concerning the physicochemical parameters of the nanoparticles whereas trehalose-containing samples were subject of a prolonged storage stability study at temperatures between -20°C and +40°C for predetermined time intervals. Shelf-life computations of the freeze-dried HI-6 nanoparticle formulations revealed a shelf-life time of 18 months when stored at -20°C. The formulations' efficacy was proven in vitro by reactivation of OP-inhibited AChE after transport over a porcine brain capillary endothelial cell layer model. Copyright © 2014 Elsevier B.V. All rights reserved.

Is plasma {beta}-glucuronidase a novel human biomarker for monitoring anticholinesterase pesticides exposure? A Malaysian experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inayat-Hussain, Salmaan H.; Lubis, Syarif Husin; Sakian, Noor Ibrahim Mohamed

A cross-sectional study was conducted to investigate the effects of acute and chronic pesticide exposure on the plasma {beta}-glucuronidase enzyme activity among five patients of acute pesticide poisoning in Tengku Ampuan Rahimah Hospital, Klang, 230 farmers in the MADA area, Kedah and 49 fishermen in Setiu, Terengganu. The duration of pesticide exposure among the patients was unknown, but the plasma samples from patients were collected on day one in the hospital. The duration of pesticide exposure among the farmers was between 1 and 45 years. The {beta}-glucuronidase activity was compared with plasma cholinesterase activity in the same individual. The plasmamore » cholinesterase activity was measured using Cholinesterase (PTC) Reagent set kit (Teco Diagnostics, UK) based on colorimetric method, while the plasma {beta}-glucuronidase activity was measured fluorometrically based on {beta}-glucuronidase assay. The plasma cholinesterase activity was significantly reduced (p < 0.05) among the patients (1386.786 {+-} 791.291 U/L/min) but the inhibition in plasma cholinesterase activity among the farmers (7346.5 {+-} 1860.786 U/L/min) was not significant (p > 0.05). The plasma {beta}-glucuronidase activity among the farmers was significantly elevated (p < 0.05) (0.737 {+-} 0.425 {mu}M/h) but not significant among the patients (p > 0.05). The plasma cholinesterase activity was positively correlated with the plasma {beta}-glucuronidase activity among the farmers (r = 0.205, p < 0.01) but not among the patients (r = 0.79, p > 0.05). Thus, plasma {beta}-glucuronidase enzyme activity can be measured as a biomarker for the chronic exposure of pesticide. However, further studies need to be performed to confirm whether plasma {beta}-glucuronidase can be a sensitive biomarker for anticholinesterase pesticide poisoning.« less

Time course of cholinesterase inhibition in adult rats treated acutely with carbaryl, carbofuran, formetanate, methomyl, methiocarb, oxamyl or propoxur

DOE Office of Scientific and Technical Information (OSTI.GOV)

Padilla, S.; Marshall, R.S.; Hunter, D.L.

To compare the toxicity of seven N-methyl carbamates, time course profiles for brain and red blood cell (RBC) cholinesterase (ChE) inhibition were established for each. Adult, male, Long Evans rats (n = 4-5 dose group) were dosed orally with either carbaryl (30 mg/kg in corn oil); carbofuran (0.5 mg/kg in corn oil); formetanate HCl (10 mg/kg in water); methomyl (3 mg/kg in water); methiocarb (25 mg/kg in corn oil); oxamyl (1 mg/kg in water); or propoxur (20 mg/kg in corn oil). This level of dosing produced at least 40% brain ChE inhibition. Brain and blood were taken from 0.5 tomore » 24 h after dosing for analysis of ChE activity using two different methods: (1) a radiometric method which limits the amount of reactivation of ChE activity, and (2) a spectrophotometric method (Ellman method using traditional, unmodified conditions) which may encourage reactivation. The time of peak ChE inhibition was similar for all seven N-methyl carbamate pesticides: 0.5-1.0 h after dosing. By 24 h, brain and RBC ChE activity in all animals returned to normal. The spectrophotometric method underestimated ChE inhibition. Moreover, there was a strong, direct correlation between brain and RBC ChE activity (radiometric assay) for all seven compounds combined (r {sup 2} = 0.73, slope 1.1), while the spectrophotometric analysis of the same samples showed a poor correlation (r {sup 2} = 0.09). For formetanate, propoxur, methomyl, and methiocarb, brain and RBC ChE inhibitions were not different over time, but for carbaryl, carbofuran and oxamyl, the RBC ChE was slightly more inhibited than brain ChE. These data indicate (1) the radiometric method is superior for analyses of ChE activity in tissues from carbamate-treated animals (2) that animals treated with these N-methyl carbamate pesticides are affected rapidly, and recover rapidly, and (3) generally, assessment of RBC ChE is an accurate predictor of brain ChE inhibition for these seven pesticides.« less

Studies on the storage stability of human blood cholinesterases : I.

DOT National Transportation Integrated Search

1970-01-01

Whole blood, red cell, and plasma preparations were stored at room temperature, refrigerated, and frozen. Samples were assayed over a 50-day period using the technique of constant-pH titration (pH-Stat). At least 90% of the cholinesterase activity in...

TLC-bioautographic evaluation of in vitro anti-tyrosinase and anti-cholinesterase potentials of sandalwood oil.

PubMed

Misra, Biswapriya B; Dey, Satyahari

2013-02-01

Sandalwood oil, rich in sesquiterpenoid alcohols, has been used in traditional medicinal systems as a relaxant and coolant. Besides, sandalwood oil is used as an ingredient in numerous skin fairness enhancing cosmetics. However, there is no available information on biological activities that relate to the above applications. Hence, the anti-tyrosinase and anti-cholinesterase potentials of sandalwood oil were probed by both TLC-bioautographic and colorimetric methods. Results obtained from colorimetric assays indicated that sandalwood oil is a potent inhibitor of tyrosinase (IC50 = 171 microg mL(-1)) and cholinesterases (IC50 = 4.8-58 microg mL(-1)), in comparison with the positive controls used in the assays, kojic acid and physostigmine, respectively. The TLC-bioautographic assays indicated that alpha-santalol, the major constituent of the oil, is a strong inhibitor of both tyrosinase and cholinesterase. These in vitro results indicate that there is a great potential of this essential oil for use in the treatment of Alzheimer's disease, as well as in skin-care.

Application of hemoperfusion in severe acute organophosphorus pesticide poisoning

PubMed

Li, Zhenhe; Wang, Guixia; Zhen, Guodong; Zhang, Yuliang; Liu, Jiaqiang; Liu, Shanmei

2017-08-23

Background/aim: The aim of this research is to investigate the clinical efficacy of hemoperfusion in the treatment of severe acute organophosphorus pesticide poisoning (AOPP). Materials and methods: Patients meeting the inclusion criteria were divided into Groups 1 and 2 according to whether hemoperfusion was applied or not. Group 2 was observed as the control group. Conventional therapy for AOPP was given to Groups 1 and 2. Besides conventional treatment, patients in Group 1 were also treated with hemoperfusion therapy. Cholinesterase activity and blood glucose concentration were tested before hemoperfusion and for the first 3 days afterwards. The recovery time of 50% cholinesterase was recorded. At the same time, the incidence and mortality of intermediate syndrome was observed and compared. Results: The incidence and mortality of intermediate syndrome in Group 1 was obviously decreased, and the recovery time of cholinesterase activity was significantly shortened compared with Group 2. Conclusion: Hemoperfusion, used for treating severe AOPP, contributes to the improvement of cholinesterase activity, low incidence and mortality of intermediate syndrome, and increase in curative rate.

Synthesis and bioevaluation of new tacrine-cinnamic acid hybrids as cholinesterase inhibitors against Alzheimer's disease.

PubMed

Chen, Yao; Zhu, Jie; Mo, Jun; Yang, Hongyu; Jiang, Xueyang; Lin, Hongzhi; Gu, Kai; Pei, Yuqiong; Wu, Liang; Tan, Renxiang; Hou, Jing; Chen, Jingyi; Lv, Yang; Bian, Yaoyao; Sun, Haopeng

2018-12-01

Small molecule cholinesterases inhibitor (ChEI) provides an effective therapeutic strategy to treat Alzheimer's disease (AD). Currently, the discovery of new ChEI with multi-target effect is still of great importance. Herein, we report the synthesis, structure-activity relationship study and biological evaluation of a series of tacrine-cinnamic acid hybrids as new ChEIs. All target compounds are evaluated for their in vitro cholinesterase inhibitory activities. The representatives which show potent activity on cholinesterase, are evaluated for the amyloid β-protein self-aggregation inhibition and in vivo assays. The optimal compound 19, 27, and 30 (human AChE IC 50  = 10.2 ± 1.2, 16.5 ± 1.7, and 15.3 ± 1.8 nM, respectively) show good performance in ameliorating the scopolamine-induced cognition impairment and preliminary safety in hepatotoxicity evaluation. These compounds deserve further evaluation for the development of new therapeutic agents against AD.

Selectivity of phenothiazine cholinesterase inhibitors for neurotransmitter systems.

PubMed

Darvesh, Sultan; Macdonald, Ian R; Martin, Earl

2013-07-01

Synthetic derivatives of phenothiazine have been used for over a century as well-tolerated drugs against a variety of human ailments from psychosis to cancer. This implies a considerable diversity in the mechanisms of action produced by structural changes to the phenothiazine scaffold. For example, chlorpromazine treatment of psychosis is related to its interaction with dopaminergic receptors. On the other hand, antagonistic action of such drugs on cholinergic receptor systems would be counter-productive for treatment of Alzheimer's disease. In a search for phenothiazines that are inhibitors of cholinesterases, especially butyrylcholinesterase, with potential to treat Alzheimer's disease, we wished to ascertain that such molecules could be devoid of neurotransmitter receptor interactions. To that end, a number of our synthetic N-10-carbonyl phenothiazine derivatives, with cholinesterase inhibitory activity, were tested for interaction with a variety of neurotransmitter receptor systems. We demonstrate that phenothiazines can be prepared without significant neurotransmitter receptor interactions while retaining high potency as cholinesterase ligands for treatment of Alzheimer's disease. Copyright © 2013 Elsevier Ltd. All rights reserved.

Novel N-allyl/propargyl tetrahydroquinolines: Synthesis via Three-component Cationic Imino Diels-Alder Reaction, Binding Prediction, and Evaluation as Cholinesterase Inhibitors.

PubMed

Rodríguez, Yeray A; Gutiérrez, Margarita; Ramírez, David; Alzate-Morales, Jans; Bernal, Cristian C; Güiza, Fausto M; Romero Bohórquez, Arnold R

2016-10-01

New N-allyl/propargyl 4-substituted 1,2,3,4-tetrahydroquinolines derivatives were efficiently synthesized using acid-catalyzed three components cationic imino Diels-Alder reaction (70-95%). All compounds were tested in vitro as dual acetylcholinesterase and butyryl-cholinesterase inhibitors and their potential binding modes, and affinity, were predicted by molecular docking and binding free energy calculations (∆G) respectively. The compound 4af (IC50 = 72 μm) presented the most effective inhibition against acetylcholinesterase despite its poor selectivity (SI = 2), while the best inhibitory activity on butyryl-cholinesterase was exhibited by compound 4ae (IC50 = 25.58 μm) with considerable selectivity (SI = 0.15). Molecular docking studies indicated that the most active compounds fit in the reported acetylcholinesterase and butyryl-cholinesterase active sites. Moreover, our computational data indicated a high correlation between the calculated ∆G and the experimental activity values in both targets. © 2016 The Authors Chemical Biology & Drug Design Published by John Wiley & Sons Ltd.

Resorcinol-, catechol- and saligenin-based bronchodilating β2-agonists as inhibitors of human cholinesterase activity.

PubMed

Bosak, Anita; Knežević, Anamarija; Gazić Smilović, Ivana; Šinko, Goran; Kovarik, Zrinka

2017-12-01

We investigated the influence of bronchodilating β2-agonists on the activity of human acetylcholinesterase (AChE) and usual, atypical and fluoride-resistant butyrylcholinesterase (BChE). We determined the inhibition potency of racemate and enantiomers of fenoterol as a resorcinol derivative, isoetharine and epinephrine as catechol derivatives and salbutamol and salmeterol as saligenin derivatives. All of the tested compounds reversibly inhibited cholinesterases with K i constants ranging from 9.4 μM to 6.4 mM and had the highest inhibition potency towards usual BChE, but generally none of the cholinesterases displayed any stereoselectivity. Kinetic and docking results revealed that the inhibition potency of the studied compounds could be related to the size of the hydroxyaminoethyl chain on the benzene ring. The additional π-π interaction of salmeterol's benzene ring and Trp286 and hydrogen bond with His447 probably enhanced inhibition by salmeterol which was singled out as the most potent inhibitor of all the cholinesterases.

Association between blood cholinesterase activity, organophosphate pesticide residues on hands, and health effects among chili farmers in Ubon Ratchathani Province, northeastern Thailand

PubMed

Nganchamung, Thitirat; Robson, Mark G; Siriwong, Wattasit

Use of pesticides has been documented to lead to several adverse health effects. Farmers are likely to be exposed to pesticides through dermal exposure as a result of mixing, loading, and spraying. Organophosphate pesticides (OPs) are widely used in most of the agricultural areas throughout Thailand. OPs are cholinesterase inhibitors and blood cholinesterase activity is used as a biomarker of OP effects. This study aims to determine the association between blood cholinesterase activity and organophosphate pesticide residues on chili farmer’s hands and their adverse health effects. Ninety chili farmers directly involved with pesticide applications (e.g. mixing, loading, spraying) were recruited and were interviewed face to face. Both enzymes, erythrocyte acetylcholinesterase (AChE) and plasma cholinesterase (PChE), were tested with the EQM Test-mate Cholinesterase Test System (Model 400). Hand wipe samples were used for collecting residues on both hands and OP residues for chlorpyrifos and profenofos were quantified using gas chromatography equipped with a flame photometric detector (GC-FPD). The average activity (±SD) of AChE and PChE was 2.73 (±0.88) and 1.58 (±0.56) U/mL, respectively. About 80.0% of the participants had detectable OP residues on hands. The median residues of chlorpyrifos and profenofos were found to be 0.02 and 0.03 mg/kg/two hands, respectively. Half of participants reported having some acute health symptoms within 48 hours after applying pesticides. When adjusted for gender, number of years working in chili farming, and frequency of pesticide use, AChE activity (Adjusted OR = 0.03, 95%CI: 0.01-0.13) and detected OP residues on hands (Adjusted OR = 0.15, 95%CI: 0.02-0.95) were significantly associated with having health effects, but no significant association was found in PChE activity (Adjusted OR = 2.09, 95%CI: 0.63-6.99). This study suggests that regular monitoring for blood cholinesterase and effective interventions to reduce pesticide exposure to prevent health effects should be provided to chili farmers.

In vitro evaluation of the effect of botanical formulations used in the control of Aedes aegypti L. (Diptera: Culicidae) on liver enzymes.

PubMed

Porto, Karla Rejane de Andrade; Motti, Priscilla Rezende; Machado, Alexandre Alves; Roel, Antonia Railda

2016-01-01

Dengue fever is a viral disease transmitted by the Aedes aegypti Linn. (1792) (Diptera: Culicidae) mosquito, which is endemic in several regions of Brazil. Alternative methods for the control of the vector include botanical insecticides, which offer advantages such as lower environmental contamination levels and less likelihood of resistant populations. Thus, in this study, the ability of botanical insecticide formulations to inhibit the activity of the liver enzymes serum cholinesterase and malate dehydrogenase was evaluated. Inhibition profiles were assessed using in vitro assays for cholinesterase and malate dehydrogenase activity and quantitated by ultraviolet-visible spectroscopy at 410nm to 340nm. Insecticide products formulated from cashew nutshell liquid [A] and ricinoleic acid [B] showed cholinesterase activity levels of 6.26IU/mL and 6.61IU/mL, respectively, while the control level for cholinesterase was 5-12IU/mL. The products did not affect the level of 0.44IU/mL established for malate dehydrogenase, as the levels produced by [A] and [B] were 0.43IU/mL and 0.45IU/mL, respectively. Our findings show that in vitro testing of the formulated products at concentrations lethal to A. aegypti did not affect the activity of cholinesterase and malate dehydrogenase, indicating the safety of these products.

A microfluorometric assay for cholinesterases, suitable for multiple kinetic determinations of picomoles of released thiocholine.

PubMed

Parvari, R; Pecht, I; Soreq, H

1983-09-01

A highly sensitive microfluorometric assay for cholinesterases has been developed. Enzymatic activity is measured by monitoring the thiocholine produced by specific hydrolysis of acetylthiocholine. This is carried out by reacting the thiocholine formed with the fluorogenic compound N-(4(7 diethylamino-4-methylcoumarin-3-yl)phenyl)maleimide to yield an intensely fluorescent product. The assay is linear over a range extending from a few picomoles to nanomoles of thiocholine. The specificity and accuracy of this microfluorometric assay were examined using microgram quantities of rat brain tissue as a source for cholinesterases. The specific activities and the Km values determined by this new method for both cholinesterase activities present in the brain (acetylcholine hydrolase, EC 3.1.1.7, and "nonspecific" cholinesterase-acylcholine acylhydrolase, EC 3.1.1.8) were identical to those reported earlier using the less sensitive spectrophotometric and radiometric methods. The background emission caused by nonenzymatic hydrolysis of the substrate is relatively low, and does not exceed background values encountered in other methods. The assay may be used for monitoring the kinetics of enzymatic activities in microscale reaction mixtures, providing a linear determination of the thiocholine produced over a period of at least 30 h at room temperature. The method can also be adapted for use in other enzymatic assays where reagents containing thiol groups can be produced or consumed.

Isolation and characterization of full-length cDNA clones coding for cholinesterase from fetal human tissues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prody, C.A.; Zevin-Sonkin, D.; Gnatt, A.

1987-06-01

To study the primary structure and regulation of human cholinesterases, oligodeoxynucleotide probes were prepared according to a consensus peptide sequence present in the active site of both human serum pseudocholinesterase and Torpedo electric organ true acetylcholinesterase. Using these probes, the authors isolated several cDNA clones from lambdagt10 libraries of fetal brain and liver origins. These include 2.4-kilobase cDNA clones that code for a polypeptide containing a putative signal peptide and the N-terminal, active site, and C-terminal peptides of human BtChoEase, suggesting that they code either for BtChoEase itself or for a very similar but distinct fetal form of cholinesterase. Inmore » RNA blots of poly(A)/sup +/ RNA from the cholinesterase-producing fetal brain and liver, these cDNAs hybridized with a single 2.5-kilobase band. Blot hybridization to human genomic DNA revealed that these fetal BtChoEase cDNA clones hybridize with DNA fragments of the total length of 17.5 kilobases, and signal intensities indicated that these sequences are not present in many copies. Both the cDNA-encoded protein and its nucleotide sequence display striking homology to parallel sequences published for Torpedo AcChoEase. These finding demonstrate extensive homologies between the fetal BtChoEase encoded by these clones and other cholinesterases of various forms and species.« less

DIAZINON AND PARATHION DIVERGE IN THEIR EFFECTS ON DEVELOPMENT OF NORADRENERGIC SYSTEMS

PubMed Central

Slotkin, Theodore A.; Skavicus, Samantha; Seidler, Frederic J.

2017-01-01

Organophosphate pesticides elicit developmental neurotoxicity through mechanisms over and above their shared property as cholinesterase inhibitors. We compared the consequences of neonatal exposure (postnatal days PN1-4) to diazinon or parathion on development of norepinephrine systems in rat brain, using treatments designed to produce equivalent effects on cholinesterase, straddling the threshold for barely-detectable inhibition. Norepinephrine levels were measured throughout development from the immediate posttreatment period (PN5), to early adolescence (PN30), young adulthood (PN60) and full adulthood (PN100); we assessed multiple brain regions containing all the major noradrenergic synaptic projections. Diazinon elicited a significant overall deficit of norepinephrine, whereas parathion produced a net increase. The effects were not immediately apparent (PN5) but rather emerged over the course of development, indicating that the organophosphate effects represent alteration of the trajectory of development, not just continuance of an initial injury. There were no comparable effects on β-adrenergic receptors, indicating that the presynaptic changes were not an adaptation to an underlying, primary effect on postsynaptic receptor signaling. Because we used the cholinesterase inhibition benchmark, the absolute dose of diazinon was much higher than that of parathion, since the latter is a more potent cholinesterase inhibitor. Our results are consistent with the growing evidence that the various organophosphates can differ in their impact on brain development and that consequently, the cholinesterase benchmark is an inadequate predictor of adverse neurodevelopmental effects. PMID:28235599

Persubstituted p-benzoquinone monoxime alkyl ethers and their molecular structure

NASA Astrophysics Data System (ADS)

Slaschinin, D. G.; Alemasov, Y. A.; Ilushkin, D. I.; Sokolenko, W. A.; Tovbis, M. S.; Kirik, S. D.

2012-05-01

Theoretical and experimental approaches were applied for the investigation of the reactivity of persubstituted 4-nitrosophenols in the reaction with alkyl iodides, in particular the potassium salt of 2,6-di(alkoxycarbonyl)-3,5-dimethyl-4-nitrosophenol. Hartre-Fock calculations showed that the anion negative charge was located mostly on the oxygen of hydroxyl group, while estimation of the total energy of the alkylated products pointed out the benefit of alkylation on the oxygen atom of the nitroso group yielding p-benzoquinone monoxime alkyl ethers. Methylation and ethylation of persubstituted nitrosophenols were carried out. The products obtained were investigated using X-ray diffraction, 1Н NMR spectroscopy and mass spectrometry. The crystal structure of the methyl ether of 2,6-di(alkoxycarbonyl)-3,5-dimethyl-1,4-benzoquinone-1-oxime (С15H19NO6) (I) was determined by the X-ray powder diffraction technique. The unit cell parameters were: a = 7.3322(6) Å, b = 10.5039(12) Å, c = 21.1520(20) Å, β = 93.742(6)°, V = 1625.58(2) Å3Z = 4, Sp.Gr. P21/c. The structure modeling was made in direct space by the Monte-Carlo approach using rigid and soft restrictions. The structure refinement was completed by the Rietveld method. It was established that the alkylation occurred on the oxygen atom of the nitroso group. The molecules (I) in the crystal structure were packed in columns along the axis a with pairwise convergence in a column up to the distance of 3.63 Å due to a 180° turn of every second molecule around the column axis. In the molecular structure the methyloxime group was oriented in the benzene plane and had π-conjugation with the ring. The ethoxycarbonyl groups were turned nearly perpendicular to the ring. Other compounds obtained had the structure of the alkyl ethers of 1.4-benzoquinone-1-oxime, which was proved by 1Н NMR spectroscopy and mass-spectrometry.

Biological and nonbiological modifications of carbamates

PubMed Central

Knaak, James B.

1971-01-01

Methylcarbamate insecticides undergo hydrolysis, oxidation, dealkylation, and conjugation in animals, plants, and insects to form similar or identical products. Carbaryl is hydroxylated in biological systems to form hydroxy, dihydro-dihydroxy, and N-hydroxymethyl carbaryl and is hydrolysed to form 1-naphthol. The products are conjugated, stored, or excreted. Carbofuran is hydroxylated at the 3 position and propoxur at the 5 position to form hydroxylated derivatives. N-hydroxymethyl derivatives of these two carbamates may also be formed. Hydrolysis appears to be the major metabolic pathway of carbofuran in the animal. Aldicarb is oxidized to its sulfoxide and then hydrolysed to the oxime sulfoxide in animals and plants. Plants hydrolyse the oxime sulfoxide to form the corresponding aldehyde, which is an intermediate in the formation of 2-methyl-2-(methyl-sulfinyl)propanol. Methomyl, which is structurally similar to aldicarb, is metabolized in plants to acetonitrile, carbon dioxide, and methylamine. Bux and Meobal undergo hydrolysis and hydroxylation to form N-hydroxy methylcarbamates, as well as hydroxybutylphenyl and hydroxymethylphenyl methylcarbamates. Zectran, which contains a dimethylamino group, is converted to the methylamino, amino, and methylformamido derivatives by insects and plants. In soil and water, methylcarbamate insecticides are hydrolysed to their respective phenols or oximes. PMID:4999481

Utilization of Nitrophenylphosphates and Oxime-Based Ligation for the Development of Nanomolar Affinity Inhibitors of the Yersinia pestis Outer Protein H (YopH) Phosphatase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bahta, Medhanit; Lountos, George T.; Dyas, Beverly

Our current study reports the first K{sub M} optimization of a library of nitrophenylphosphate-containing substrates for generating an inhibitor lead against the Yersinia pestis outer protein phosphatase (YopH). A high activity substrate identified by this method (K{sub M} = 80 {micro}M) was converted from a substrate into an inhibitor by replacement of its phosphate group with difluoromethylphosphonic acid and by attachment of an aminooxy handle for further structural optimization by oxime ligation. A cocrystal structure of this aminooxy-containing platform in complex with YopH allowed the identification of a conserved water molecule proximal to the aminooxy group that was subsequently employedmore » for the design of furanyl-based oxime derivatives. By this process, a potent (IC{sub 50} = 190 nM) and nonpromiscuous inhibitor was developed with good YopH selectivity relative to a panel of phosphatases. The inhibitor showed significant inhibition of intracellular Y. pestis replication at a noncytotoxic concentration. The current work presents general approaches to PTP inhibitor development that may be useful beyond YopH.« less

40 CFR 161.34 - Flagging of studies for potential adverse effects.

Code of Federal Regulations, 2010 CFR

2010-07-01

... a type listed in paragraph (b) of this section to support an application for new or amended... feeding study or combined chronic feeding/oncogenicity study 83-1 Cholinesterase inhibition NOEL less than... ADI 9 Subchronic feeding study 82-1 Cholinesterase inhibition NOEL less than 100 times the current...

COMPARISON OF ACUTE NEUROBEHAVIORAL AND CHOLINESTERASE INHIBITORY EFFECTS OF N-METHYL CARBAMATES IN RAT

EPA Science Inventory

There are few studies evaluating direct functional and biochemical consequences of exposure. In the present study of the acute toxicity of seven N-methyl carbamate pesticides, we evaluated the dose-response profiles of cholinesterase (ChE) inhibition in brain and erythrocytes (R...

Relationship Between Brain and Plasma Carbaryl Levels and Cholinesterase Inhibition

EPA Science Inventory

Carbaryl is a N-methylcarbamate pesticide and, like others in this class, is a reversible inhibitor of cholinesterase (ChE) enzymes. Although studied for many years, there is a surprising lack of information relating tissue levels of carbaryl with ChE activity in the same animals...

Assay techniques for detection of exposure to sulfur mustard, cholinesterase inhibitors, sarin, soman, GF, and cyanide. Technical bulletin

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-05-01

This technical bulletin provides analytical techniques to identify toxic chemical agents in urine or blood samples. It is intended to provide the clinician with laboratory tests to detect exposure to sulfur mustard, cholinesterase inhibitors, sarin, soman, GF, and cyanide.

DIFFERENTIAL PROFILES OF CHOLINESTERASE INHIBITION AND NEUROBEHAVIORAL EFFECTS IN RATS EXPOSED TO FENAMIPHOS AND PROFENOPHOS.

EPA Science Inventory

The relationship between cholinesterase (ChE) inhibition and neurobehavioral changes was examined using two ChE-inhibiting organophosphorus pesticides, fenamiphos and profenophos. Both pesticides inhibit blood ChE, yet brain ChE is relatively spared (little to no inhibition up t...

BEHAVIORAL AND NEUROCHEMICAL EFFECTS OF ACUTE CHLORPYRIFOS IN RATS: TOLERANCE TO PROLONGED INHIBITION OF CHOLINESTERASE

EPA Science Inventory

Chlorpyrifos (CPF), a commercially prevalent organophosphate (OP) pesticide, inhibits blood and brain cholinesterase for up to 10 weeks after acute s.c. injection in rats. his prolonged inhibition suggested that acute CPF may affect muscarinic receptors and behavior as does repea...

Design, synthesis, biological evaluation, and molecular modeling studies of chalcone-rivastigmine hybrids as cholinesterase inhibitors.

PubMed

Wang, Ling; Wang, Yu; Tian, Yiguang; Shang, Jinling; Sun, Xiaoou; Chen, Hongzhuan; Wang, Hao; Tan, Wen

2017-01-01

A series of novel chalcone-rivastigmine hybrids were designed, synthesized, and tested in vitro for their ability to inhibit human acetylcholinesterase and butyrylcholinesterase. Most of the target compounds showed hBChE selective activity in the micro- and submicromolar ranges. The most potent compound 3 exhibited comparable IC 50 to the commercially available drug (rivastigmine). To better understand their structure activity relationships (SAR) and mechanisms of enzyme-inhibitor interactions, kinetic and molecular modeling studies including molecular docking and molecular dynamics (MD) simulations were carried out. Furthermore, compound 3 blocks the formation of reactive oxygen species (ROS) in SH-SY5Y cells and shows the required druggability and low cytotoxicity, suggesting this hybrid is a promising multifunctional drug candidate for Alzheimer's disease (AD) treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Design, synthesis and evaluation of novel dual monoamine-cholinesterase inhibitors as potential treatment for Alzheimer's disease.

PubMed

Liu, Wei; Lang, Ming; Youdim, Moussa B H; Amit, Tamar; Sun, Yewei; Zhang, Zaijun; Wang, Yuqiang; Weinreb, Orly

2016-10-01

Current novel therapeutic approach suggests that multifunctional compounds with diverse biological properties and a single bioavailability and pharmacokinetic metabolism, will produce higher significant advantages in treatment of neurodegenerative diseases, such as Alzheimer's disease (AD). Based on this rational, a new class of cholinesterase (ChE)-monoamine oxidase (MAO) inhibitors were designed and synthesized by amalgamating the propargyl moiety of the irreversible selective MAO-B inhibitor, neuroprotective/neurorestorative anti-Parkinsonian drug, rasagiline, into the "N-methyl" position of the ChE inhibitor, anti-AD drug rivastigmine. Initially, we examined the MAO and ChE inhibitory effect of these novel compounds, MT series in vitro and in vivo. Among MT series, MT-031 exhibited higher potency as a dual MAO-A and ChE inhibitor compared to other compounds in acute-treated mice. Additionally, MT-031 was found to increase the striatal levels of dopamine (DA), serotonin (5-HT) and norepinephrine (NE), and prevent the metabolism of DA and 5-HT. Finally, we have demonstrated that MT-031 exerted neuroprotective effect against H2O2-induced neurotoxicity and reactive oxygen species generation in human neuroblastoma SH-SY5Y cells. These findings provide evidence that MT-031 is a potent brain permeable novel multifunctional, neuroprotective and MAO-A/ChE inhibitor, preserves in one molecule entity some of the beneficial properties of its parent drugs, rasagiline and rivastigmine, and thus may be indicated as novel therapeutic approach for AD. Copyright © 2016 Elsevier Ltd. All rights reserved.

Differences between male and female rhesus monkey erythrocyte acetylcholinesterase and plasma cholinesterase activity before and after exposure to sarin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woodard, C.L.; Calamaio, C.A.; Kaminskis, A.

The female rhesus monkey has a menstrual cycle like the human. Additionally, several differences in enzyme levels between males and females and in the female during the menstrual cycle are present. Therefore we quantitated plasma cholinesterase (ChE/BuChE) and erythrocyte (RBC) acetylcholinesterase (AChE) activity before and after exposure to sarin (GB)(1 5 ug/kg, iv; a 0.75 LD50), in male and female rhesus (Macaca mulatta) monkeys. Twenty-eight-day preexposure baseline plasma ChE and RBC AChE values for six male and six female rhesus monkeys were compared for intra-animal, within sex and between sex differences. After these baseline values were obtained, the organophosphorus (OP)more » compound/Isopropyl methylphosphono-fluoridate (GB) was administered to atropinized monkeys to determine if there was a significant in vivo difference between the sexes in their response to this intoxication in regard to the rate of BuChE /AChE inhibition, pyridine-2-aldoxime methyl chloride (2-PAM) reactivation of the phosphonylated BuChE and the rate of aging of the phosphonylated:BuChE/AChE. In the pre-exposure portion of the protocol; the intra-animal and intra-group BuChE/AChE variations were found to be minimal; but there were significant differences between the male and female monkeys in both plasma BuChE and RBC AChE levels; although probably clinically insignificant in respect to an OP intoxication. No significant cyclic fluctuations were seen during the 28-day study in either sex.« less

[Phosphoric acid ester preparations used in cattle, swine and sheep with special reference to cholinesterase activity. 4. Use of phosphoric acid esters and their effect on acetylcholinesterase activity in sheep].

PubMed

Mieth, K; Beier, D; Losch, K

1975-01-01

The use of organophosphorus preparations for the control of ectoparasites and endoparasites of sheep, particularly systemic application, is discussed. Experiments on 13 groups of sheep with five preparations produced in the German Democratic Republic in various formulations and concentrations showed that external application had good contact activity, but little was absorbed. Acetylcholinesterase activity was not inhibited, except by pour-on application of doses several times the normal dose. The preparations were arranged in order of cholinesterase inhibition. In contrast to cattle, diminished cholinesterase activity was unreliable as in indicator of systemic toxicity of organophosphorus preparations in sheep.

Dual inhibitors of cholinesterases and monoamine oxidases for Alzheimer's disease.

PubMed

Knez, Damijan; Sova, Matej; Košak, Urban; Gobec, Stanislav

2017-05-01

Accumulating evidence indicates a solid relationship between several enzymes and Alzheimer's disease. Cholinesterases and monoamine oxidases are closely associated with the disease symptomatology and progression and have been tackled simultaneously using several multifunctional ligands. This design strategy offers great chances to alter the course of Alzheimer's disease, in addition to alleviation of the symptoms. More than 15 years of research has led to the identification of various dual cholinesterase/monoamine oxidase inhibitors, while some showing positive outcomes in clinical trials, thus giving rise to additional research efforts in the field. The aim of this review is to provide an update on the novel dual inhibitors identified recently and to shed light on their therapeutic potential.

Advances toward multifunctional cholinesterase and β-amyloid aggregation inhibitors.

PubMed

Panek, Dawid; Wichur, Tomasz; Godyń, Justyna; Pasieka, Anna; Malawska, Barbara

2017-10-01

The emergence of a multitarget design approach in the development of new potential anti-Alzheimer's disease agents has resulted in the discovery of many multifunctional compounds focusing on various targets. Among them the largest group comprises inhibitors of both cholinesterases, with additional anti-β-amyloid aggregation activity. This review describes recent advances in this research area and presents the most interesting compounds reported over a 2-year span (2015-2016). The majority of hybrids possess heterodimeric structures obtained by linking structurally active fragments interacting with different targets. Multipotent cholinesterase inhibitors with β-amyloid antiaggregating activity may additionally possess antioxidative, neuroprotective or metal-chelating properties or less common features such as anti-β-secretase or τ-antiaggregation activity.

Quantitative distributions of different cholinesterases and inhibition of acetylcholinesterase by metidathion and paraquat in alimentary canal of common carp.

PubMed

Láng, G; Kufcsák, O; Szegletes, T; Nemcsók, J

1997-07-01

1. The cholinesterases play an important role in the innervation of organs. The ratio of solubilized to membrane-bound cholinesterase and the quantitative distributions of acetylcholinesterase and butyrylcholinesterase were measured in different segments of the gut of carp (Cyprinus carpio) connected with different types of nerve-muscle synapses in different parts of the alimentary tract. 2. The inhibition of acetylcholinesterase (EC 3.1.1.7.) by the herbicide paraquat and the insecticide metidathion was measured in different parts of the gut of carp. 3. Metidathion and paraquat significantly decreased the activity of acetylcholinesterase in different segments of the alimentary tract of common carp, in a concentration-dependent manner.

RELATIONSHIPS BETWEEN TISSUE LEVELS OF CARBARYL, A PROTOTYPICAL CARBAMATE PESTICIDE, AND CHOLINESTERASE INHIBITION IN LONG EVANS RATS.

EPA Science Inventory

As part of an effort to link pharmacokinetics with biochemical and physiological endpoints, the relationships between cholinesterase (ChE) activity and tissue levels of a prototypical N-methyl carbamate pesticide were examined. In a dose-response study, carbaryl (0, 3, 7.5, 15, 3...

INHIBITION OF BRAIN CHOLINESTERASE AND THE PHOTIC AFTER DISCHARGE OF FLASH EVOKED POTENTIALS PRODUCED BY CARBARYL IN LONG EVANS RATS.

EPA Science Inventory

Carbaryl is a widely used N-methyl carbamate pesticide that acts by inhibiting cholinesterases (ChE), which may lead to cholinergic toxicity. Flash evoked potentials (FEPs) are a neurophysiological response often used to detect central nervous system (CNS) changes following expos...

BRAIN CHOLINESTERASE INHIBITION PRODUCED BY PROPOXUR AND DEPRESSION OF THE PHOTIC AFTER DISCHARGE OF FLASH EVOKED POTENTIALS IN LONG EVANS RATS.

EPA Science Inventory

Propoxur is a widely used N-methyl carbamate pesticide that acts by inhibiting cholinesterases (ChE), which may lead to cholinergic toxicity. Flash evoked potentials (FEPs) are a neurophysiological response following stimulation of the visual system with flashes of light. They ar...

Serum and Plasma Cholinesterase Activity in the Cape Griffon Vulture (Gyps coprotheres).

PubMed

Naidoo, Vinny; Wolter, Kerri

2016-04-28

Vulture (Accipitridae) poisonings are a concern in South Africa, with hundreds of birds dying annually. Although some of these poisonings are accidental, there has been an increase in the number of intentional baiting of poached rhinoceros (Rhinocerotidae) and elephant (Elephantidae) carcasses to kill vultures that alert officials to poaching sites by circling overhead. The primary chemicals implicated are the organophosphorous and carbamate compounds. Although most poisoning events can be identified by dead vultures surrounding the scavenged carcass, weak birds are occasionally found and brought to rehabilitation centers for treatment. The treating veterinarian needs to make an informed decision on the cause of illness or poisoning prior to treatment. We established the reference interval for serum and plasma cholinesterase activity in the Cape Griffon Vulture ( Gyps coprotheres ) as 591.58-1,528.26 U/L, providing a clinical assay for determining potential exposure to cholinesterase-depressing pesticides. Both manual and automated samplers were used with the butyrylthiocholine method. Species reference intervals for both serum and plasma cholinesterase showed good correlation and manual and automated measurements yielded similar results.

Isolation and characterization of full-length cDNA clones coding for cholinesterase from fetal human tissues.

PubMed Central

Prody, C A; Zevin-Sonkin, D; Gnatt, A; Goldberg, O; Soreq, H

1987-01-01

To study the primary structure and regulation of human cholinesterases, oligodeoxynucleotide probes were prepared according to a consensus peptide sequence present in the active site of both human serum pseudocholinesterase (BtChoEase; EC 3.1.1.8) and Torpedo electric organ "true" acetylcholinesterase (AcChoEase; EC 3.1.1.7). Using these probes, we isolated several cDNA clones from lambda gt10 libraries of fetal brain and liver origins. These include 2.4-kilobase cDNA clones that code for a polypeptide containing a putative signal peptide and the N-terminal, active site, and C-terminal peptides of human BtChoEase, suggesting that they code either for BtChoEase itself or for a very similar but distinct fetal form of cholinesterase. In RNA blots of poly(A)+ RNA from the cholinesterase-producing fetal brain and liver, these cDNAs hybridized with a single 2.5-kilobase band. Blot hybridization to human genomic DNA revealed that these fetal BtChoEase cDNA clones hybridize with DNA fragments of the total length of 17.5 kilobases, and signal intensities indicated that these sequences are not present in many copies. Both the cDNA-encoded protein and its nucleotide sequence display striking homology to parallel sequences published for Torpedo AcChoEase. These findings demonstrate extensive homologies between the fetal BtChoEase encoded by these clones and other cholinesterases of various forms and species. Images PMID:3035536

THE LOCALIZATION OF CHOLINESTERASE ACTIVITY IN RAT CARDIAC MUSCLE BY ELECTRON MICROSCOPY

PubMed Central

Karnovsky, Morris J.

1964-01-01

A method has been developed for localizing sites of cholinesterase activity in rat cardiac muscle by electron microscopy. The method utilizes thiocholine esters as substrates, and is believed to be dependent on the reduction of ferricyanide to ferrocyanide by thiocholine released by enzymatic activity. The ferrocyanide thus formed is captured by copper to form fine, electron-opaque deposits of copper ferrocyanide, which sharply delineate sites of enzymatic activity at the ultrastructural level. Cholinesterase activity in formalin-fixed heart muscle was localized: (a) in longitudinal elements of the sarcoplasmic reticulum, but not in the T, or transverse, elements; and (b) in the A band, with virtually no activity noted in the M band, or in the H zone. The I band was also negative. No activity was detected in the sarcolemma, or in invaginations of the sarcolemma at the level of the Z band. The perinuclear element of the sarcoplasmic (endoplasmic) reticulum was frequently strongly positive. Activity at all sites was completely abolished by omitting the substrates, or by inhibition with eserine 10-4 M and diisopropylfluorophosphate 10-5 M. Eserine 10-5 M completely inhibited reaction in the sarcoplasmic reticulum, and virtually abolished that in the A band. These observations, together with the use of the relatively specific substrates and suitable controls to eliminate non-enzymatic staining, indicate that cholinesterase activity was being demonstrated. The activity in rat heart against different substrates was that of non-specific cholinesterases, in accordance with biochemical data. The activity in the A band was considered to be probably due to myosincholinesterase. It is proposed that the localization of cholinesterases in myocardium at the ultrastructural level should be taken into account in considering the possible functions of these myocardial enzymes, and it is hoped that knowledge of their localization will open up new avenues of approach in considering their physiological role in myocardium, which at present is not definitely known. PMID:14222810

Caregiver Acceptance of Adverse Effects and Use of Cholinesterase Inhibitors in Alzheimer's Disease

ERIC Educational Resources Information Center

Oremus, Mark; Wolfson, Christina; Vandal, Alain C.; Bergman, Howard; Xie, Qihao

2007-01-01

Caregivers play a determining role in choosing treatments for persons with Alzheimer's disease. The objective of this study was to examine caregivers' willingness to have persons with Alzheimer's disease continue taking cholinesterase inhibitors in the event that any 1 of 11 adverse effects was to occur. Data were gathered via postal questionnaire…

CHOLINESTERASE INHIBITION AND HYPOTHERMIA FOLLOWING EXPOSURE TO BINARY MIXTURES OF ANTICHOLINESTERASE AGENTS: LACK OF EVIDENCE FOR CAUSE-AND-EFFECT

EPA Science Inventory

Dose-additivity has been the default assumption in risk assessments of pesticides with a common mechanism of action but it has been suspected that there could be non-additive effects. Inhibition of plasma cholinesterase (ChE) activity and hypothermia were used as benchmarks of e...

Cholinesterase Inhibition and Depression of the Photic After Discharge of Flash Evoked Potentials Following Acute or Repeated Exposures to a Mixture of Carbaryl and Propoxur

EPA Science Inventory

While information exists regarding inhibition of cholinesterase (ChE) activity, little is known about neurophysiological changes produced by a mixture of N-methyl carbamate pesticides. Previously, we reported that acute treatment with propoxur or carbaryl decreased the duration o...

Continuously recording body temperature in terrestrial chelonians

USGS Publications Warehouse

Nussear, K.E.; Esque, T.C.; Tracy, C.R.

2002-01-01

The degree of interaction between mercury and cholinesterase inhibiting pesticides was determined by comparing enzyme responses to sublethal dosages of parathion or carbofuran in quail fed 0.05, 0.5, or 5.0 ppm morsodren for 18 weeks. A statistically significant interaction was defined as greater brain cholinesterase inhibition in morsodren-fed than in clean-fed birds following pesticide dosage. The tissue residues of mercury that accumulated before significant mercury-parathion interactions occurred were higher than levels that might be expected in natural populations, but significant mercury-carbofuran interactions occurred in birds that had only accumulated 1.0 ppm liver mercury. The results indicate that indiscriminate usage of cholinesterase inhibiting pesticides are dangerous, since natural populations of fish-eating birds oftentimes contain this magnitude of mercury.

Rapid kinetic characterization of glycosyl hydrolases based on oxime derivatization and nanostructure-initiator mass spectrometry (NIMS).

PubMed

Deng, Kai; Takasuka, Taichi E; Heins, Richard; Cheng, Xiaoliang; Bergeman, Lai F; Shi, Jian; Aschenbrener, Ryan; Deutsch, Sam; Singh, Seema; Sale, Kenneth L; Simmons, Blake A; Adams, Paul D; Singh, Anup K; Fox, Brian G; Northen, Trent R

2014-07-18

Glycoside hydrolases (GHs) are critical to cycling of plant biomass in the environment, digestion of complex polysaccharides by the human gut microbiome, and industrial activities such as deployment of cellulosic biofuels. High-throughput sequencing methods show tremendous sequence diversity among GHs, yet relatively few examples from the over 150,000 unique domain arrangements containing GHs have been functionally characterized. Here, we show how cell-free expression, bioconjugate chemistry, and surface-based mass spectrometry can be used to study glycoside hydrolase reactions with plant biomass. Detection of soluble products is achieved by coupling a unique chemical probe to the reducing end of oligosaccharides in a stable oxime linkage, while the use of (13)C-labeled monosaccharide standards (xylose and glucose) allows quantitation of the derivatized glycans. We apply this oxime-based nanostructure-initiator mass spectrometry (NIMS) method to characterize the functional diversity of GHs secreted by Clostridium thermocellum, a model cellulolytic organism. New reaction specificities are identified, and differences in rates and yields of individual enzymes are demonstrated in reactions with biomass substrates. Numerical analyses of time series data suggests that synergistic combinations of mono- and multifunctional GHs can decrease the complexity of enzymes needed for the hydrolysis of plant biomass during the production of biofuels.

Coordination properties of the oxime analogue of glycine to Cu(II).

PubMed

Georgieva, I; Trendafilova, N; Rodríguez-Santiago, L; Sodupe, M

2005-06-30

The coordination of Cu2+ by glyoxilic acid oxime (gao)--the oxime analogue of glycine amino acid--and its deprotonated (gao- and gao2-) species has been studied with different density functional methods. Single-point calculations have also been carried out at the single- and double- (triple) excitation coupled-cluster (CCSD(T)) level of theory. The isomers studied involve coordination of Cu2+ to electron-rich sites (O,N) of neutral, anionic, and dianionic gao species in different conformations. In contrast to Cu2+-glycine, for which the ground-state structure is bidentate with the CO2(-) terminus of zwitterionic glycine, for Cu2+-gao the most stable isomer shows monodentate binding of Cu2+ with the carbonylic oxygen of the neutral form. The most stable complexes of Cu2+ interacting with deprotonated gao species (gao- and gao2-) also take place through the carboxylic oxygens but in a bidentate manner. The results with different functionals show that, for these open shell (Cu2+-L) systems, the relative stability of complexes with different coordination environments (and so, different spin distribution) can be quite sensitive to the amount of "Hartree-Fock" exchange included in the functional. Among all the functionals tested in this work, the BHandHLYP is the one that better compares to CCSD(T) results.

A facile and efficient synthesis of some (6E)-hydroximino-4-en-3-one steroids, steroidal oximes from Cinachyrella spp. sponges.

PubMed

Cui, Jianguo; Huang, Liliang; Fan, Lei; Zhou, Aimin

2008-03-01

Using beta-sitosterol as a starting material, (6E)-hydroximino-24-ethylcholest-4-en-3-one (1), a natural steroidal oxime from Cinachyrella alloclada and C. apion, was synthesized in four steps with a high overall yield. First, beta-sitosterol (5a) is transformed into the corresponding 24-ethylcholest-4-en-3,6-dione (6a) via oxidation with pyridinium chlorochromate (PCC). Selective reduction of 6a by NaBH(4) in the presence of CoCl(2) gives 24-ethylcholest- 4-en-3beta-ol-6-one (7a). The reaction of 7a with hydroxylamine hydrochloride offers the oxime 8a and the oxidation of 8a by Jones reagent gives the target steroid 1. (6E)-Hydroximinocholest-4-en-3-one (2) and (6E)-hydroximino-24-ethylcholest-4,22-dien-3-one (4) were synthesized by a similar method. The cytotoxicity of the synthesized compounds against sk-Hep-1 (human liver carcinoma cell line), H-292 (human lung carcinoma cell line), PC-3 (human prostate carcinoma cell line) and Hey-1B (human ovarian carcinoma cell line) cells were investigated. The presence of a cholesterol-type side chain appears to be necessary for the biological activity.

Trimethylsilyl speciations of cathine, cathinone and norephedrine followed by gas chromatography mass spectrometry: Direct sample preparation and analysis of khatamines.

PubMed

Molnár, Borbála; Fodor, Blanka; Boldizsár, Imre; Molnár-Perl, Ibolya

2016-04-01

A literature criticism is given on methods using currently gas chromatography mass spectrometry (GC/MS) to determine cathine (CAT), cathinone (CTN) and norephedrine (NE), jointly khatamines. In this study, khatamines' oximation, trimethylsilylation and mass fragmentation properties-applying N-Methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA), its trimethyliodosilane (TMIS) catalyst containing version (MSTFA(TMIS)), N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and hexamethyldisilazane (HMDS)-was highlighted, at first. Derivatization, mass fragmentation and quantitation related, optimized model investigations have been carried out as a function of the reaction times and conditions. Special emphasis was put (i) on the stability of the primarily formed (CAT-2TMS, NE-2TMS, CTN-TMS(TMS-oximes)1,2), then transformed, fully derived (CAT-3TMS, NE-3MTS, CTN-2TMS(TMS-oximes)1,2) species, and, (ii) on the proportionally formed stable products, suitable to selective quantitation of all three natural amines, simultaneously. Results, as novelty to the field confirmed that (i) TMIS catalyzed trimethylsilyation triggers to form fully derivatized species unfortunately, in part only; while, (ii) khatamines' simultaneous quantitation needs to be carried out in a two steps derivatization process consisting of oximation (1st step, hydroxylamine in pyridine) and trimethylsilylation (2nd step, MSTFA), to the CAT-2TMS, NE-2TMS, CTN-TMS(TMS-oximes)1,2. These species were characterized with their retention, mass fragmentation and analytical performance properties, in model solutions and in the presence of plant tissues, as well: R(2), limit of quantitation (LOQ) data, expressed in pg/1μL injection basis, proved to be 62.5pg (CAT), 20pg (NE) and 62.5pg (CTN), respectively. The practical utility of proposal was enormously enhanced by the novel, direct sample preparation method. In this process, the freshly harvested, freeze-dried, then pulverized leaves of Catha edulis FORKS were directly derivatized, in the presence of the matrix. Reproducibility (in average 2.07 RSD% varying between 0.15 and 5.5 RSD%), linearity (0.9990-0.9994) and recovery (95.7-99.1%) values of the new sample preparation protocol was confirmed by the standard addition method for CAT, NE and CTN equally. From plant leaf, 0.061w/w% CAT and 0.014w/w% NE contents were obtained. In this tissue CTN was not found. Very likely attributable to the unfavorable climate for the plant: grown in Hungary of temperate zone and naturalized in the tropical Africa. Copyright © 2016 Elsevier B.V. All rights reserved.

Chronic administration of cholesterol oximes in mice increases transcription of cytoprotective genes and improves transcriptome alterations induced by alpha-synuclein overexpression in nigrostriatal dopaminergic neurons

PubMed Central

Richter, Franziska; Gao, Fuying; Medvedeva, Vera; Lee, Patrick; Bove, Nicholas; Fleming, Sheila M.; Michaud, Magali; Lemesre, Vincent; Patassini, Stefano; De La Rosa, Krystal; Mulligan, Caitlin K.; Sioshansi, Pedrom; Zhu, Chunni; Coppola, Giovanni; Bordet, Thierry; Pruss, Rebecca; Chesselet, Marie-Françoise

2014-01-01

Cholesterol-oximes TRO19622 and TRO40303 target outer mitochondrial membrane proteins and have beneficial effects in preclinical models of neurodegenerative diseases leading to their advancement to clinical trials. Dopaminergic neurons degenerate in Parkinson’s disease (PD) and are prone to oxidative stress and mitochondrial dysfunction. In order to provide insights into the neuroprotective potential of TRO19622 and TRO40303 for dopaminergic neurons in vivo, we assessed their effects on gene expression in laser captured nigrostriatal dopaminergic neurons of wildtype mice and of mice that over-express alpha-synuclein, a protein involved in both familial and sporadic forms of PD (Thy1-aSyn mice). Young mice were fed the drugs in food pellets or a control diet from 1 to 4 months of age, approximately 10 months before the appearance of striatal dopamine loss in this model. Unbiased weighted gene co-expression network analysis (WGCNA) of transcriptional changes revealed effects of cholesterol oximes on transcripts related to mitochondria, cytoprotection and anti-oxidant response in wild-type and transgenic mice, including increased transcription of stress defense (e.g. Prdx1, Prdx2, Glrx2, Hspa9, Pink1, Drp1, Trak1) and dopamine-related (Th, Ddc, Gch1, Dat, Vmat2, Drd2, Chnr6a) genes. Even at this young age transgenic mice showed alterations in transcripts implicated in mitochondrial function and oxidative stress (e.g. Bcl-2, Bax, Casp3, Nos2), and both drugs normalized about 20% of these alterations. Young Thy1-aSyn mice exhibit motor deficits that differ from parkinsonism and are established before the onset of treatment; these deficits were not improved by cholesterol oximes. However, high doses of TRO40303 improved olfaction and produced the same effects as dopamine agonists on a challenging beam test, specifically an increase in footslips, an observation congruent with its effects on transcripts involved in dopamine synthesis. High doses of TRO19622 increased alpha-synuclein aggregates in the substantia nigra; this effect, not seen with TRO40303 was inconsistent and may represent a protective mechanism as in other neurodegenerative diseases. Overall, the results suggest that cholesterol oximes, while not improving early effects of alpha-synuclein overexpression on motor behavior or pathology, may ameliorate the function and resilience of dopaminergic neurons in vivo and support further studies of neuroprotection in models with dopaminergic cell loss. PMID:24844147

Evaluation of reversible interconversion in comprehensive two-dimensional gas chromatography using enantioselective columns in first and second dimensions.

PubMed

Kröger, Sabrina; Wong, Yong Foo; Chin, Sung-Tong; Grant, Jacob; Lupton, David; Marriott, Philip J

2015-07-24

The reversible molecular interconversion behaviour of a synthesised oxime (2-phenylpropanaldehyde oxime; (C6H5)CH(CH3)CHN(OH)) was investigated by both, single dimensional gas chromatography (1D GC) and comprehensive two-dimensional gas chromatography (GC×GC). Previous studies on small molecular weight oximes were extended to this larger aromatic oxime (molar mass 149.19gmol(-1)) with interest in the extent of interconversion, enantioselective resolution, and retention time. On a polyethylene glycol (PEG; wax-type) column, a characteristic interconversion zone between two antipodes of E and Z isomers was formed by molecules which have undergone isomerisation on the column (E⇌Z). The extent of interconversion was investigated by varying chromatographic conditions (oven temperature and carrier flow rate) to understand the nature of the behaviour observed. The extent of interconversion was negligible in both enantioselective and methyl-phenylpolysiloxane phase-columns, correlating with the low polarity of the stationary phase. In order to obtain isomerisation along with enantio-resolution, a wax-type and an enantioselective column were coupled in either enantioselective-wax or wax-enantioselective order. The most appropriate column arrangement was selected for study by using a GC×GC experiment with either a wax-phase or phenyl-methylpolysiloxane phase as (2)D column. In addition to evaluation of these fast elution columns, a long narrow-bore enantioselective column (10m) was introduced as (2)D, providing an enantioselective-PEG (coupled-column ensemble: (1)D1+(1)D2)×enantioselective ((2)D) column combination. In this instance, the (1)D1 enantioselective column provides enantiomeric separation of the corresponding enantiomers ((R) and (S)) of (E)- and (Z)-2-phenylpropanaldehyde oxime, followed by E/Z isomerisation in the coupled (1)D2 PEG (reactor) column. The resulting chromatographic interconversion region was modulated and separated into either E/Z isomers (achiral (2)D column) or into the respective (R) and (S) enantiomers of the E/Z isomers when using a (2)D enantioselective column. With this arrangement, the isomers underneath the broad interconversion plateau in 1D elution profiles, including the enantiomers, could be resolved, illuminating salient features and understanding of the molecular reversible process of the interconverting molecules during the chromatographic elution. The two-dimensional patterns (contour plots), resulting from the combination of interconversion process and chiral separation, are discussed phenomenologically. Copyright © 2015 Elsevier B.V. All rights reserved.

Fluorescent Chemosensors for Toxic Organophosphorus Pesticides: A Review

PubMed Central

Obare, Sherine O.; De, Chandrima; Guo, Wen; Haywood, Tajay L.; Samuels, Tova A.; Adams, Clara P.; Masika, Noah O.; Murray, Desmond H.; Anderson, Ginger A.; Campbell, Keith; Fletcher, Kenneth

2010-01-01

Many organophosphorus (OP) based compounds are highly toxic and powerful inhibitors of cholinesterases that generate serious environmental and human health concerns. Organothiophosphates with a thiophosphoryl (P=S) functional group constitute a broad class of these widely used pesticides. They are related to the more reactive phosphoryl (P=O) organophosphates, which include very lethal nerve agents and chemical warfare agents, such as, VX, Soman and Sarin. Unfortunately, widespread and frequent commercial use of OP-based compounds in agricultural lands has resulted in their presence as residues in crops, livestock, and poultry products and also led to their migration into aquifers. Thus, the design of new sensors with improved analyte selectivity and sensitivity is of paramount importance in this area. Herein, we review recent advances in the development of fluorescent chemosensors for toxic OP pesticides and related compounds. We also discuss challenges and progress towards the design of future chemosensors with dual modes for signal transduction. PMID:22163587

Fluorescent chemosensors for toxic organophosphorus pesticides: a review.

PubMed

Obare, Sherine O; De, Chandrima; Guo, Wen; Haywood, Tajay L; Samuels, Tova A; Adams, Clara P; Masika, Noah O; Murray, Desmond H; Anderson, Ginger A; Campbell, Keith; Fletcher, Kenneth

2010-01-01

Many organophosphorus (OP) based compounds are highly toxic and powerful inhibitors of cholinesterases that generate serious environmental and human health concerns. Organothiophosphates with a thiophosphoryl (P=S) functional group constitute a broad class of these widely used pesticides. They are related to the more reactive phosphoryl (P=O) organophosphates, which include very lethal nerve agents and chemical warfare agents, such as, VX, Soman and Sarin. Unfortunately, widespread and frequent commercial use of OP-based compounds in agricultural lands has resulted in their presence as residues in crops, livestock, and poultry products and also led to their migration into aquifers. Thus, the design of new sensors with improved analyte selectivity and sensitivity is of paramount importance in this area. Herein, we review recent advances in the development of fluorescent chemosensors for toxic OP pesticides and related compounds. We also discuss challenges and progress towards the design of future chemosensors with dual modes for signal transduction.

Histochemical discrimination of fibers in regenerating rat infraorbital nerve

NASA Technical Reports Server (NTRS)

Wilke, R. A.; Riley, D. A.; Sanger, J. R.

1992-01-01

In rat dorsal root ganglia, histochemical staining of carbonic anhydrase (CA) and cholinesterase (CE) yields a reciprocal pattern of activity: Sensory processes are CA positive and CE negative, whereas motor processes are CA negative and CE positive. In rat infraorbital nerve (a sensory peripheral nerve), we saw extensive CA staining of nearly 100% of the myelinated axons. Although CE reactivity in myelinated axons was extremely rare, we did observe CE staining of unmyelinated autonomic fibers. Four weeks after transection of infraorbital nerves, CA-stained longitudinal sections of the proximal stump demonstrated 3 distinct morphological zones. A fraction of the viable axons retained CA activity to within 2 mm of the distal extent of the stump, and the stain is capable of resolving growth sprouts being regenerated from these fibers. Staining of unmyelinated autonomic fibers in serial sections shows that CE activity was not retained as far distally as is the CA sensory staining.

Identification by CI-mass spectrometry of an unexpected benzodiazepine degradation product

NASA Astrophysics Data System (ADS)

Buret, D.; Breton, D.; Clair, P.; Lafosse, M.

2006-01-01

The French Military Health Service (SSA) has developed an innovative drug product, as a treatment against neurotoxic organophosphate poisoning (NOP). It contains three drug substances: an anticholinergic, an anticonvulsant and a cholinesterase reactivator. Testing stability study, in normal conditions, over 18 months, for this speciality, has given unexpected results. Indeed, one of the drug substances, avizafone (pro-drug of diazepam), breaks down partially into a compound which migrates into the plastic container where this degradation product is demethylated after absorption. Mass spectrometry with negative chemical ionisation (negative CI-MS) was used, to monitor decomposition of the drug substance. This method first showed migration of the degradation product and has been used to monitor its evolution during the stability testing study. The demethylation seems to be due to an additive product present in the plastic. The degradation products remain trapped in the container holding the pharmaceutical formulation.

Anti-cholinesterase activity of the standardized extract of Syzygium aromaticum L.

PubMed

Dalai, Manoj K; Bhadra, Santanu; Chaudhary, Sushil K; Bandyopadhyay, Arun; Mukherjee, Pulok K

2014-04-01

Clove (Syzygium aromaticum) is a well-known culinary spice with strong aroma; contains a high amount of oil known as clove oil. The major phyto-constituent of the clove oil is eugenol. Clove and its oil possess various medicinal uses in indigenous medicine as an antiseptic, anti-oxidant, analgesic and neuroprotective properties. Thus, it draws much attention among researchers from pharmaceutical, food and cosmetic industries. The aim of the present study was to determine the anti-cholinesterase activity of the methanol extract of clove, its oil and eugenol. In vitro anti-cholinesterase activity of S. aromaticum was performed by a thin layer chromatography bio autography, 96 well micro titer plate and kinetic methods. Reverse phase high performance liquid chromatography (RP-HPLC) analysis was carried out to identify the biomarker compound eugenol in clove oil. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition study revealed that eugenol possess better inhibition of the enzymes than extract and oil. Clove extract, its oil and eugenol showed better inhibition of AChE than BChE. Polyphenolic compound eugenol was detected through RP-HPLC analysis. The content of eugenol in essential oil was found to be 0.5 μg/ml. Kinetic analysis of the cholinesterase inhibition study of the extract; clove oil and eugenol have shown that they possess mixed type of inhibition for AChE and non-competitive type of inhibition for BChE. These results might be useful in explaining the effect of clove as anti-cholinesterase agent for the management of cognitive ailments like Alzheimer's disease.

Simultaneous usage of dementia medications and anticholinergics among Asians and Pacific Islanders.

PubMed

Schultz, Brian R; Takeshita, Junji; Goebert, Deborah; Takeshita, Steven; Lu, Brett Y; Guilloux, Alexandre; Higa, Joy

2017-11-01

The simultaneous use of dementia medications and anticholinergic medications occurs frequently. Cholinesterase inhibitors and anticholinergic medications likely counteract one another, potentially exposing patients to medications with decreased benefit, more adverse effects, and higher cost of care. We identified the rate of concurrent prescriptions of cholinesterase inhibitors/memantine with anticholinergics in an urban hospital setting with a large Asian and Pacific Islander population. This study is a retrospective review of patients hospitalized from 1 January 2006 to 31 December 2010 at a general hospital who simultaneously received US Food and Drug Administration-approved dementia medications (galantamine, rivastigmine, donepezil, and/or memantine) and anticholinergics. Overall, 304 patients receiving cholinesterase inhibitors/memantine also received anticholinergics. Of these patients, 64.1% were given high-potency anticholinergic medications, and 35.9% received medium-potency medications. Indications for the use of anticholinergic medication were urological (17.8%), gastrointestinal excluding nausea (32.6%), nausea (10.2%), psychiatric (7.9%), and other (31.6%). Asian patients received the combination of cholinesterase inhibitors/memantine and anticholinergics less frequently than Native Hawaiian or Caucasian patients (8.4% vs 12.2% and 13.3%, respectively; χ 2  = 16.04, degrees of freedom = 2, P < 0.0003). Simultaneous prescribing of cholinesterase inhibitors, memantine, and anticholinergic medications was significantly less common than in previous studies, with some ethnic variability. The less frequent occurrence of concurrent medications in the Asian population may be because of variations in the rate of indications or in tolerability for anticholinergic medications among the population. © 2017 Japanese Psychogeriatric Society.

Distribution of cholinesterases in insects*

PubMed Central

Booth, G. M.; Lee, An-Horng

1971-01-01

The study of toxicology and other related fields has been largely based on in vitro techniques. These methods have provided quantitative information on the effects of inhibitors on enzymes, but none on the localized effects of inhibitors on selected sites of action within the animal. Histochemical study of frozen sections does provide data on the site of action of toxicants. The utility of histochemistry in conjunction with in vitro methods is discussed. The substrates acetylthiocholine and phenyl thioacetate were utilized in demonstrating cholinesterase. Neither substrate penetrated well into freshly dissected nerve cord preparations, but both compounds were hydrolysed by sectioned tissue. The leaving group of phenyl thioacetate was demonstrated to be benzenethiol. In general, acetylthiocholine was hydrolysed slightly more rapidly by insect cholinesterases. A unique cholinesterase was found in motor end-plates of cricket muscle, which hydrolyses acetylthiocholine and which was inhibited by physostigmine. No other insect muscle preparation showed this activity. Topical application of insecticides showed that a vital site of action in flies is the peripheral area of the thoracic ganglia and that in crickets the brain and nerve cord are involved at knock-down. Kinetic data indicate that acetylthiocholine has a greater affinity than does phenyl thioacetate for a variety of enzyme sources. Ultrastructural evidence shows that cholinesterases that hydrolyse acetylthiocholine are membrane-bound. Phenyl thioacetate was found to be useful as a model in designing new insecticides. ImagesFig. 5Fig. 6Fig. 7Fig. 8Fig. 13Fig. 14Fig. 15Fig. 16Fig. 9Fig. 10Fig. 11Fig. 12Fig. 1Fig. 2Fig. 3Fig. 4Fig. 17Fig. 18Fig. 19 PMID:5315359

Cholinesterase inhibitors modify the activity of intrinsic cardiac neurons.

PubMed

Darvesh, Sultan; Arora, Rakesh C; Martin, Earl; Magee, David; Hopkins, David A; Armour, J Andrew

2004-08-01

Cholinesterase inhibitors used to treat the symptoms of Alzheimer's disease (AD) inhibit both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), albeit to different degrees. Because central and peripheral neurons, including intrinsic cardiac neurons located on the surface of the mammalian heart, express both BuChE and AChE, we studied spontaneously active intrinsic cardiac neurons in the pig as a model to assess the effects of inhibition of AChE compared to BuChE. Neuroanatomical experiments showed that some porcine intrinsic cardiac neurons expressed AChE and/or BuChE. Enzyme kinetic experiments with cholinesterase inhibitors, namely, donepezil, galantamine, (+/-) huperzine A, metrifonate, rivastigmine, and tetrahydroaminoacridine, demonstrated that these compounds differentially inhibited porcine AChE and BuChE. Donepezil and (+/-) huperzine A were better reversible inhibitors of AChE, and galantamine equally inhibited both the enzymes. Tetrahydroaminoacridine was a better reversible inhibitor of BuChE. Rivastigmine caused more rapid inactivation of BuChE as compared to AChE. Neurophysiological studies showed that acetylcholine and butyrylcholine increase or decrease the spontaneous activity of the intrinsic cardiac neurons. Donepezil, galantamine, (+/-) huperzine A, and tetrahydroaminoacridine changed spontaneous neuronal activity by about 30-35 impulses per minute, while rivastigmine changed it by approximately 100 impulses per minute. It is concluded that (i) inhibition of AChE and BuChE directly affects the porcine intrinsic cardiac nervous system, (ii) the intrinsic cardiac nervous system represents a suitable model for examining the effects of cholinesterase inhibitors on mammalian neurons in vivo, and (iii) the activity of intrinsic cardiac neurons may be affected by pharmacological agents that inhibit cholinesterases.

Cholinesterase inhibitors for patients with Alzheimer's disease: systematic review of randomised clinical trials

PubMed Central

Kaduszkiewicz, Hanna; Zimmermann, Thomas; Beck-Bornholdt, Hans-Peter; van den Bussche, Hendrik

2005-01-01

Objectives Pharmacological treatment of Alzheimer's disease focuses on correcting the cholinergic deficiency in the central nervous system with cholinesterase inhibitors. Three cholinesterase inhibitors are currently recommended: donepezil, rivastigmine, and galantamine. This review assessed the scientific evidence for the recommendation of these agents. Data sources The terms “donepezil”, “rivastigmine”, and “galantamine”, limited by “randomized-controlled-trials” were searched in Medline (1989-November 2004), Embase (1989-November 2004), and the Cochrane Database of Systematic Reviews without restriction for language. Study selection All published, double blind, randomised controlled trials examining efficacy on the basis of clinical outcomes, in which treatment with donepezil, rivastigmine, or galantamine was compared with placebo in patients with Alzheimer's disease, were included. Each study was assessed independently, following a predefined checklist of criteria of methodological quality. Results 22 trials met the inclusion criteria. Follow-up ranged from six weeks to three years. 12 of 14 studies measuring the cognitive outcome by means of the 70 point Alzheimer's disease assessment scale—cognitive subscale showed differences ranging from 1.5 points to 3.9 points in favour of the respective cholinesterase inhibitors. Benefits were also reported from all 12 trials that used the clinician's interview based impression of change scale with input from caregivers. Methodological assessment of all studies found considerable flaws—for example, multiple testing without correction for multiplicity or exclusion of patients after randomisation. Conclusion Because of flawed methods and small clinical benefits, the scientific basis for recommendations of cholinesterase inhibitors for the treatment of Alzheimer's disease is questionable. PMID:16081444

Brain cholinesterase inhibition in songbirds from pecan groves sprayed with phosaline and disulfoton

USGS Publications Warehouse

White, D.H.; Seginak, J.T.

1990-01-01

Disulfoton at 0.83 kg/ha caused moderate to severe brain cholinesterase (ChE) depression in 11 of 15 blue jays collected in pecan groves 6-7 hr after the application. Phosalone at 0.83 kg/ha to pecan groves caused only slight ChE inhibition in a few blue jays and red-bellied woodpeckers.