Rec #: 11470
Keywords: CHEM METHODS
Notes: Chemical of Concern: MLN
Abstract: Abstract: Representative organophosphorus and carbamate insecticides were subjected to a recently developed, efficient spectrophotometric cutinase assay. The inactivation ability of ten organophosphate oxons [chlorpyrifos oxon, chlorpyrifos-methyl oxon, paraoxon, paraoxon-methyl, malaoxon, dichlorvos, monocrotophos, chlorfenvinphos, demeton-S-methyl, acephate], five organophosphate thions [chlorpyrifos, chlorpyrifos-methyl, parathion, parathion-methyl, malathion] and six carbamates [methomyl, carbaryl, propoxur, carbofuran, ethiofencarb, pirimicarb] was examined and characterized in terms of inhibitory rate constants. Regarding their strengths as cutinase inhibitors, organophosphate oxons were found to exceed by far the corresponding thions, whereas ethyl esters proved to be superior to their methyl analogues. Chlorpyrifos oxon with an inhibition constant k i of 9.4 x 10âµ L/(mol min) was identified as strongest cutinase inhibitor, resulting in a detection limit of 2 ĂŽÂĽg/L (standard solution/sample extract). As novel result it is established that also carbamates are cutinase inhibitors, though of minor strength as compared to organophosphate oxons. Most efficient carbamates are methomyl and carbaryl with inhibition constants of 7.5 x 10² and 2.6 x 10² L/(mol min), respectively, i.e., well in the range of organophosphorous insecticides.
Keywords: Enzyme assay
Number of Volumes: 5
Berlin/Heidelberg : Springer-Verlag http://dx.doi.org/10.1007/s00217-007-0642-8
676. Wananukul, S.; Chatproedprai, S.; Tempark, T., and Wananukul, W. Clinical Response and Safety of Malathion Shampoo for Treatment of Head Lice in a Primary School.
Rec #: 9140
Keywords: HUMAN HEALTH
Notes: Chemical of Concern: MLN
Abstract: ABSTRACT: OBJECTIVE: Help eradicate or at least alleviating head lice in a primary school with malathion shampoo and to study clinical response and safety of malathion shampoo.
ABSTRACT: MATERIAL AND METHOD: All students were examined by using a fine-toothed lice comb to help detect live lice. Direct visual examination and the collection of nits for microscopic examination were performed to differentiate viable nits from empty nits. Diagnosis of head lice was made by the presence of lice. All students that had lice and/or nits were treated with malathion shampoo. Malathion shampoo was also provided for all family members. Pediculocidal efficacy was by the presence or absence of live lice. Blood for red blood cell cholinesterase activity was drawn in 32 volunteers before treatment and after the second treatment.
ABSTRACT: RESULTS: At the first visit, 629 students were examined and 48 students had live head lice. The infestation rate was 13% in girls and 1.3% in boys. The cure rate was 93% after the first treatment. The reported side effects were nausea, a burning sensation, and irritation that was found in five (4%), 10 (7%) and three (2%) students respectively. The mean of RBC cholinesterase activity before and after two applications showed significant changes (p = 0.03). It was -7.5 +/- 4.1% reduction from the initial, but all were in the normal range. There was no report of clinical manifestation of malathion toxicity.
ABSTRACT: CONCLUSION: Malathion shampoo is safe and effective in the treatment of head lice. There is significant skin absorption so a scalp examination for head lice should be done before subsequent application to avoid unnecessary exposure.
MESH HEADINGS: Adolescent
MESH HEADINGS: Animals
MESH HEADINGS: Biological Markers
MESH HEADINGS: Child
MESH HEADINGS: Cholinesterases/blood
MESH HEADINGS: Female
MESH HEADINGS: Follow-Up Studies
MESH HEADINGS: Humans
MESH HEADINGS: Insecticides/*adverse effects/therapeutic use
MESH HEADINGS: Lice Infestations/diagnosis/*drug therapy
MESH HEADINGS: Malathion/*adverse effects/therapeutic use
MESH HEADINGS: Male
MESH HEADINGS: Pediculus/*drug effects
MESH HEADINGS: Scalp Dermatoses/diagnosis/*drug therapy
MESH HEADINGS: Schools
MESH HEADINGS: Students
MESH HEADINGS: Treatment Outcome eng
677. Wang, Jun-Liang; Xia, Qing; Zhang, an-Ping; Hu, Xiao-Yan, and Lin, Chun-Mian. Determination of Organophosphorus Pesticide Residues in Vegetables by an Enzyme Inhibition Method Using [Alpha]-Naphthyl Acetate Esterase Extracted From Wheat Flour. 2012 Apr; 13, (4): 267-73.
Rec #: 5830
Keywords: CHEM METHODS
Notes: Chemical of Concern: MLN
Abstract: Abstract: The widespread use of organophosphorus pesticides (OPs) poses a great threat to human health and has made the detection of OP residues in food an important task, especially in view of the fact that easy and rapid detection methods are needed. Because OPs have inhibitory effects on the activity of α-naphthyl acetate esterase (ANAE) in plants, in this work we evaluated the possibility of detecting OPs in vegetables with ANAE extracted from commercial flour. The limits of detection (LODs) obtained for methamidophos, dichlorvos, phoxim, dimethoate, and malathion in lettuce samples with crude ANAE were 0.17, 0.11, 0.11, 0.96, and 1.70 mg/kg, respectively. Based on the maximum residue limits (MRLs) for OPs in food stipulated by Chinese laws which are 0.05, 0.20, 0.05, 1.00, and 8.00 mg/kg for methamidophos, dichlorvos, phoxim, dimethoate, and malathion, respectively, the esterase inhibition method with crude ANAE had sufficient sensitivity to detect the residues of dichlorvos, dimethoate, and malathion in lettuce, but it could not be used to guarantee the safety of the same samples if methamidophos or phoxim residue was present. The sensitivity of the method was improved by the use of esterase purified by ammonium sulfate salting-out. The LODs obtained for methamidophos and phoxim with purified esterase were lower than the MRLs for these OPs in food. This is a very promising method for the detection of OP residues in vegetables using crude or purified esterase because of its cheapness, sensitivity, and convenience.[PUBLICATION ABSTRACT]
Keywords: Pesticides -- analysis
Keywords: Organophosphorus Compounds -- analysis
Keywords: Plant Extracts
Keywords: Food Contamination -- analysis
Keywords: Organophosphorus Compounds -- chemistry
Keywords: Plant Extracts -- chemistry
Keywords: Pesticides -- chemistry
Keywords: Food Analysis -- methods
Keywords: Organophosphorus Compounds
Keywords: Vegetables -- chemistry
Keywords: Pesticides
Keywords: Medical Sciences
Keywords: Naphthol AS D Esterase -- chemistry
Keywords: Flour
Keywords: Triticum -- enzymology
Keywords: Naphthol AS D Esterase English. Copyright - Zhejiang University and Springer-Verlag Berlin Heidelberg 2012. Last updated - 2013-05-22. DOI - 2624408431; 68337492; 138046; JZHV; 22467368; SPVLJZHV115851343191
678. Wang, Kemin ; Yang, Dongzhi; Xiao, Ming; Chen, Xiangmei; Lu, Fengmin, and Nie, Jun. Sesamin as a co-initiator for unfilled dental restorations. 2009 Sep; 5, (7): 2508-2517.
Rec #: 2290
Keywords: NO TOXICANT
Notes: Chemical of Concern: MLN
Abstract: A natural component, sesamin (SA), was used to replace conventional amine as co-initiator for dental composite. A combination of camphorquinone (CQ) and SA was employed to initiate the photopolymerization of 2-2-bis[4-(2-hydroxy-3-methacryloxyprop-1-oxy)phenyl] propane/triethylene glycol dimethacrylate (70/30 wt.%). The kinetics was recorded by real-time Fourier transform infrared spectroscopy. The mechanical properties were measured by dynamic mechanical analysis, the cell toxicity was investigated by MTT assay and a mixture of CQ and ethyl 4-N,N-dimethylaminobenzoate (EDMAB) was used as control in the same photocuring condition. The results indicated that the addition of SA as co-initiator greatly improved the rate of polymerization and final double-bond conversion (DC) when compared with the system initiated by CQ alone. Compared with EDMAB, the final DC of the CQ/SA system (71%) was slightly lower than that of CQ/EDMAB (76%); SA resulted in approximately the same storage modulus at around 37 -_C, but a slightly higher glass transition temperature. SA produced lower yellowing effect and good in vitro biocompatibility. The water sorption and solubility for two mixtures were very close and within the range of the ISO 4049 specification. These results suggest that SA is an effective alternative co-initiator to conventional amine. The natural compound characteristics of SA make it more promising than amine in dental resin formulations. Dental composite/ FTIR/ Mechanical property/ Polymerization/ MTT http://www.sciencedirect.com/science/article/pii/S174270610900110X
679. Wang, X. L.; Qiao, X. G.; Ma, Y.; Zhao, T., and Xu, Z. X. Simultaneous Determination of Nine Trace Organophosphorous Pesticide Residues in Fruit Samples Using Molecularly Imprinted Matrix Solid-Phase Dispersion Followed by Gas Chromatography. 2013; 61, 3821-3827.
Rec #: 16430
Keywords: CHEM METHODS
Notes: Chemical of Concern: MLN
Abstract: Abstract: How to determine trace multipesticide residues in fruits is an important problem. This paper reports a molecularly imprinted polymer (MIP) that was prepared using 4-(dimethoxyphosphorothioylamino)butanoic acid as the template, acrylamide as the functional monomer, and ethylene glycol dimethacrylate (EGDMA) as the cross-linker. The novel imprinted polymer was characterized by static and kinetic adsorption experiments, and it exhibited good recognition ability and fast adsorption-desorption dynamicd toward trichlorfon, malathion, acephate, methamidophos, omethoate, dimethoate, phosphamidon, monocrotophos, and methyl parathion. Using this imprinted polymer as sorbent, matrix solid-phase dispersion coupled to gas chromatography for simultaneous determination of nine trace organophosphorus pesticide residues was first presented. Under the optimized conditions, the LOD (S/N = 3) of this method for the nine organophosphorus was 0.3-1.6 mu g kg(-1); the RSD for three replicate extractions ranged from 1.2 to 4.8%. The apple and pear samples spiked with nine organophosphate pesticides at levels of 20 and 100 mu g kg(-1) were determined according to this method with good recoveries ranging from 81 to 105%. Moreover, this developed method was successfully applied to the quantitative detection of the nine organophosphorus pesticide residues in orange samples.
Number of Volumes: 16
ISI Document Delivery No.: 134IX ://CCC:000318204700008
680. Wang, Yonggang; Aker, Winfred G.; Hwang, Huey-min; Yedjou, Clement G.; Yu, Hongtao, and Tchounwou, Paul B. A study of the mechanism of in vitro cytotoxicity of metal oxide nanoparticles using catfish primary hepatocytes and human HepG2 cells. 2011 Oct 15-; 409, (22): 4753-4762.
Rec #: 900
Keywords: IN VITRO
Notes: Chemical of Concern: MLN
Abstract: Nanoparticles (NPs), including nanometal oxides, are being used in diverse applications such as medicine, clothing, cosmetics and food. In order to promote the safe development of nanotechnology, it is essential to assess the potential adverse health consequences associated with human exposure. The liver is a target site for NP toxicity, due to NP accumulation within it after ingestion, inhalation or absorption. The toxicity of nano-ZnO, TiO2, CuO and Co3O4 was investigated using a primary culture of channel catfish hepatocytes and human HepG2 cells as in vitro model systems for assessing the impact of metal oxide NPs on human and environmental health. Some mechanisms of nanotoxicity were determined by using phase contrast inverted microscopy, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, reactive oxygen species (ROS) assays, and flow cytometric assays. Nano-CuO and ZnO showed significant toxicity in both HepG2 cells and catfish primary hepatocytes. The results demonstrate that HepG2 cells are more sensitive than catfish primary hepatocytes to the toxicity of metal oxide NPs. The overall ranking of the toxicity of metal oxides to the test cells is as follows: TiO2 < Co3O4 < ZnO < CuO. The toxicity is due not only to ROS-induced cell death, but also to damages to cell and mitochondrial membranes. Cytotoxicity/ Nanoparticle/ Metal oxide/ Catfish/ Primary hepatocyte/ HepG2 cell http://www.sciencedirect.com/science/article/pii/S0048969711007571
681. Wang, Yuanfeng and Du, Ran. Simultaneous extraction of trace organophosphorous pesticides from plasma sample by automated solid phase extraction and determination by gas chromatography coupled with pulsed flame photometric detector: The 47th International Conference of the International Association of Forensic Toxicologists (TIAFT). 2010 May 20-; 198, (1Çô3): 70-73.
Rec #: 2270
Keywords: CHEM METHODS
Notes: Chemical of Concern: MLN
Abstract: The purpose of our work was to develop a simple and efficient analytical method for simultaneous determination of different species of organic phosphorus pesticides from plasma sample by using automated solid phase extraction (SPE) and gas chromatography/pulsed flame photometric detector (GC/PFPD) as a diagnostic tool. Firstly, the developed extraction method was validated using 5 certified reference materials; then, it was applied to plasma sample. Such factors as the category and volume of wash and elution solvent were examined separately. Among these factors, the category of elution solvent is most important. HexaneÇôacetone (50:50, v/v) seems to be the best choice for it. The eluent was evaporated on a nitrogen stream at room temperature and redissolved by acetone. 1 ++L of aliquots was chromatographed on GC/PFPD. Response versus the amount of pesticides injected ranging from 0.05 to 2 ng showed a good linearity. The detection limits were 0.01 ng for dimethoate, 0.03 ng for methyl-parathion and malathion, 0.04 ng for terbufos and 0.02 ng for parathion. Extraction recoveries range from 84.3% to 109.1%.This extraction method for multispecies analysis incorporates many benefits in terms of speed, low solvent use, accuracy of measurement, sensitivity, relative simplicity, as well as the time saving and convenience of multiple species measurement through sample preparation and analysis as an integrated step. Organophosphorous pesticides/ SPE/ GC/PFPD/ Plasma sample http://www.sciencedirect.com/science/article/pii/S0379073809005544
682. Wenger, B. S. Protease Inhibition as a Teratogenic Mechanism. 1974; 14, (4): 1305-(ABS).
Rec #: 410
Keywords: ABSTRACT
Notes: Chemical of Concern: DCTP,MLN
683. Wiley, J. S.; Garcia-Reyes, J. F.; Harper, J. D.; Charipar, N. A.; Ouyang, Z., and Cooks, R. G. Screening of agrochemicals in foodstuffs using low-temperature plasma (LTP) ambient ionization mass spectrometry. 2010; 135, 971-979.
Rec #: 16480
Keywords: CHEM METHODS
Notes: Chemical of Concern: MLN
Abstract: Abstract: Low-temperature plasma (LTP) permits direct ambient ionization and mass analysis of samples in their native environment with minimal or no prior preparation. LTP utilizes dielectric barrier discharges (DBDs) to create a low power plasma which is guided by gas flow onto the sample from which analytes are desorbed and ionized. In this study, the potential of LTP-MS for the detection of pesticide residues in food is demonstrated. Thirteen multi-class agricultural chemicals were studied (ametryn, amitraz, atrazine, buprofezin, DEET, diphenylamine, ethoxyquin, imazalil, isofenphosmethyl, isoproturon, malathion, parathion-ethyl and terbuthylazine). To evaluate the potential of the proposed approach, LTP-MS experiments were performed directly on fruit peels as well as on fruit/vegetable extracts. Most of the agrochemicals examined displayed remarkable sensitivity in the positive ion mode, giving limits of detection (LOD) for the direct measurement in the low picogram range. Tandem mass spectrometry (MS/MS) was used to confirm identification of selected pesticides by using for these experiments spiked fruit/vegetable extracts (QuEChERS, a standard sample treatment protocol) at levels as low as 1 pg, absolute, for some of the analytes. Comparisons of the data obtained by direct LTP-MS were made with the slower but more accurate conventional LC-MS/MS procedure. Herbicides spiked in aqueous solutions were detectable at LODs as low as 0.5 mg L(-1) without the need for any sample preparation. The results demonstrate that ambient LTP-MS can be applied for the detection and confirmation of traces of agrochemicals in actual market-purchased produce and in natural water samples. Quantitative analysis was also performed in a few selected cases and displayed a relatively high degree of linearity over four orders of magnitude.
Number of Volumes: 5
ISI Document Delivery No.: 588AG ://CCC:000277037500018
684. Wille, Timo; Thiermann, Horst, and Worek, Franz. In Vitro Kinetic Interactions of Deet, Pyridostigmine and Organophosphorus Pesticides With Human Cholinesterases. 2011 Apr 25; 190, (2-3): 79-83.
Rec #: 3510
Keywords: HUMAN HEALTH
Notes: Chemical of Concern: MLN
Abstract: Abstract: The simultaneous use of the repellent DEET, pyridostigmine, and organophosphorus pesticides has been assumed as a potential cause for the Gulf War Illness and combinations have been tested in different animal models. However, human in vitro data on interactions of DEET with other compounds are scarce and provoked the present in vitro study scrutinizing the interactions of DEET, pyridostigmine and pesticides with human acetylcholinesterase (hAChE) and butyrylcholinesterase (hBChE). DEET showed to be a weak and reversible inhibitor of hAChE and hBChE. The IC(50) of DEET was calculated to be 21.7mM DEET for hAChE and 3.2mM DEET for hBChE. The determination of the inhibition kinetics of pyridostigmine, malaoxon and chlorpyrifos oxon with hAChE in the presence of 5mM DEET resulted in a moderate reduction of the inhibition rate constant k(i). The decarbamoylation velocity of pyridostigmine-inhibited hAChE was not affected by DEET. In conclusion, the in vitro investigation of interactions between human cholinesterases, DEET, pyridostigmine, malaoxon and chlorpyrifos oxon showed a weak inhibition of hAChE and hBChE by DEET. The inhibitory potency of the tested cholinesterase inhibitors was not enhanced by DEET and it did not affect the regeneration velocity of pyridostigmine-inhibited AChE. Hence, this in vitro study does not give any evidence of a synergistic effect of the tested compounds on human cholinesterases. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
Keywords: Cholinesterase Inhibitors -- pharmacology
Keywords: 2921-88-2
Keywords: Drug Interactions
Keywords: Acetylcholinesterase
Keywords: Cholinesterase Inhibitors -- chemistry
Keywords: Humans
Keywords: Pyridostigmine Bromide -- pharmacology
Keywords: Butyrylcholinesterase
Keywords: Chlorpyrifos -- pharmacology
Keywords: Malathion -- analogs & derivatives
Keywords: 134-62-3
Keywords: Malathion
Keywords: Pesticides -- chemistry
Keywords: Organophosphorus Compounds
Keywords: Malathion -- chemistry
Keywords: Acetylcholinesterase -- metabolism
Keywords: Pyridostigmine Bromide
Keywords: EC 3.1.1.7
Keywords: Pyridostigmine Bromide -- chemistry
Keywords: malaoxon
Keywords: EC 3.1.1.-
Keywords: Chlorpyrifos -- chemistry
Keywords: Index Medicus
Keywords: Pesticides -- pharmacology
Keywords: Organophosphorus Compounds -- chemistry
Keywords: O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphate
Keywords: DEET -- chemistry
Keywords: DEET -- pharmacology
Keywords: 101-26-8
Keywords: Chlorpyrifos
Keywords: Malathion -- pharmacology
Keywords: Cholinesterase Inhibitors
Keywords: 0
Keywords: DEET
Keywords: Kinetics
Keywords: 5598-15-2
Keywords: Chlorpyrifos -- analogs & derivatives
Keywords: Pesticides
Keywords: 1634-78-2
Keywords: 121-75-5 eng. Date completed - 2011-07-26. Date created - 2011-04-25. Date revised - 2012-12-20. SuppNotes - Comment In: Chem Biol Interact. 2011 Aug 15;193(1):107; author reply 108[21473857]. Last updated - 2013-01-19. DOI - MEDL-21354413; 21354413; 1872-7786
685. Wilnai, Y.; Seaver, L. H., and Enns, G. M. Atypical Amyoplasia Congenita in an Infant With Leigh Syndrome: A Mitochondrial Cause of Severe Contractures? 2012; 158A, 2353-2357.
Rec #: 16500
Keywords: HUMAN HEALTH
Notes: Chemical of Concern: MLN
Abstract: Abstract: Amyoplasia congenita is a distinct form of arthrogryposis with characteristic features including internally rotated and adducted shoulders, extended elbows, flexion, and ulnar deviation of the wrists, and adducted thumbs. Fetal hypokinesia, secondary to a variety of genetic conditions, neuromuscular disorders, and environmental agents, is associated with contractures. In order to increase our understanding of the phenotypic spectrum associated with SURF 1 deficiency, a common cause of mitochondrial respiratory chain complex IV deficiency and Leigh syndrome, we describe a now 6-year-old boy who presented in the neonatal period with amyoplasia congenita. His development was normal until age 10.5 months, at which time he developed severe hypotonia and choreoathetosis following an episode of viral gastroenteritis. Following the onset of neurological symptoms, he gradually developed severe kyphosis and lower limb contractures. Blood and cerebrospinal fluid lactate levels were elevated and head imaging showed characteristic features of Leigh syndrome. He was found to harbor two pathogenic heterozygous mutations in the SURF 1 gene. In this case, mitochondrial dysfunction and the resultant energy deficiency may have played a role in causing abnormal neuronal development during embryogenesis, causing arthrogryposis. A variety of mitochondrial respiratory chain complex deficiencies have been associated with contractures of varying severity. Therefore, mitochondrial disorders should be considered in the differential diagnosis of neonatal arthrogryposis, especially if other characteristic findings such as lactic acidemia or basal ganglia abnormalities are present. (C) 2012 Wiley Periodicals, Inc.
Number of Volumes: 9
ISI Document Delivery No.: 023WU ://CCC:000310068700041
686. Wilson, B. W.; Rusli, F. J.; Tam, M. K. Y.; DePeters, E., and Henderson, J. D. Carbamate Protection of AChE Against Inhibition by Agricultural Chemicals. 2012; 26, 506-509.
Rec #: 16510
Keywords: HUMAN HEALTH
Notes: Chemical of Concern: MLN
Abstract: Abstract: The carbamate pyridostigmine bromide has been used as a pretreatment to protect individuals from the nerve agent soman. Previous research showed that pyridostigmine significantly protected human muscle acetylcholinesterase in vitro from soman and bovine red blood cell acetylcholinesterase from some organophosphorous pesticides. Research presented here demonstrates that pretreatment with other carbamates also protects acetylcholinesterase from inhibition by the pesticides chlorpyrifos-oxon and diazinon-oxon, but not from malaoxon. (C) 2012 Wiley Periodicals, Inc. J Biochem Mol Toxicol 26: 506-509, 2012; View this article online at wileyonlinelibrary.com. DOI10.1002/jbt.21456
Number of Volumes: 12
ISI Document Delivery No.: 073XS ://CCC:000313777000004
687. Winter, Carl K; Katz, Josh M, and Katz, Josh M. Dietary Exposure to Pesticide Residues From Commodities Alleged to Contain the Highest Contamination Levels. 2011 Jan; 2011.
Rec #: 6680
Keywords: HUMAN HEALTH
Notes: Chemical of Concern: MLN
Abstract: Abstract: Probabilistic techniques were used to characterize dietary exposure of consumers to pesticides found in twelve commodities implicated as having the greatest potential for pesticide residue contamination by a United States-based environmental advocacy group. Estimates of exposures were derived for the ten most frequently detected pesticide residues on each of the twelve commodities based upon residue findings from the United States Department of Agriculture's Pesticide Data Program. All pesticide exposure estimates were well below established chronic reference doses (RfDs). Only one of the 120 exposure estimates exceeded 1% of the RfD (methamidophos on bell peppers at 2% of the RfD), and only seven exposure estimates (5.8 percent) exceeded 0.1% of the RfD. Three quarters of the pesticide/commodity combinations demonstrated exposure estimates below 0.01% of the RfD (corresponding to exposures one million times below chronic No Observable Adverse Effect Levels from animal toxicology studies), and 40.8% had exposure estimates below 0.001% of the RfD. It is concluded that (1) exposures to the most commonly detected pesticides on the twelve commodities pose negligible risks to consumers, (2) substitution of organic forms of the twelve commodities for conventional forms does not result in any appreciable reduction of consumer risks, and (3) the methodology used by the environmental advocacy group to rank commodities with respect to pesticide risks lacks scientific credibility.
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