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Chemophobia and the Boy Who Cried Wolf
Published in David Lightsey, The Myths about Nutrition Science, 2019
The other pesticide used on the apples was phosmet, which is used to help control for apple maggot, something no one wants in their apple when they bite into it. Phosmet does not penetrate the produce flesh, and the EPA mandates a waiting period of seven days post-application before apples can be harvested, not 24 hours as used in this study. The EPA has set a tolerance level of 10ppm, which is 10 grams per 2,200 pounds of apples. However, as with all pesticides, this is not what the consumer is exposed to, if any. The 2014 USDA sampling data demonstrate detection levels of 0.005–0.280ppm. Again, these are incredibly low numbers, almost a non-existent detection level. Most samplings were below the 0.076ppm levels, and this would be prior to the consumer rinsing them off with water at home.
Protein-Based Bioscavengers of Organophosphorus Nerve Agents
Published in Brian J. Lukey, James A. Romano, Salem Harry, Chemical Warfare Agents, 2019
Moshe Goldsmith, Yacov Ashani, Tamara. C. Otto, C. Linn Cadieux, David. S. Riddle
A closely related homolog of PTE named OpdA (accession number EU002557), which has a 90% amino acid sequence identity to PTE, was isolated from a soil bacterial strain called Agrobacterium radiobacter P230 in Australia (Horne et al., 2002). They mainly differ in the C-terminal part of the protein, where OpdA is longer than PTE by 20 amino acids. Unlike PTE, OpdA can hydrolyze the pesticides fenthion and phosmet and displays higher turnover rates with OPs that have shorter side chains (Horne et al., 2002). Similarly to PTE, OpdA was found to hydrolyze the toxic isomers of soman and cyclosarin with moderate efficiencies (i.e., kcat/KM = 3.5 and 2.3 × 104 M−1 min−1, respectively) but was less efficient with the toxic isomers of VX (kcat/KM = 2.7 × 102 M−1 min−1), RVX (kcat/KM = 2 × 102 M−1 min−1), and CVX (kcat/KM = 2.3 × 102 M−1 min−1) (Wille et al., 2012).
Pesticides and Chronic Diseases
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
In this study of 678 licensed pesticide applicators with well-characterized lifetime exposure to OP pesticides, their findings provide evidence that long-term exposure to some OP pesticides may be associated with selected indices of poorer NS function among pesticide applicators with no previous history of diagnosed pesticide poisoning. The most consistent associations were with the clinical NPx outcomes, particularly toe proprioception, which was significantly associated with ever use of chlorpyrifos, coumaphos, dichlorvos, fonofos, phosmet, and tetrachlorvinphos. Furthermore, monotonic increases in OPs were observed for abnormal toe proprioception and chlopyrifos, fonofos, and phosmet. Especially for this outcome, the number of pesticides with significant adverse associations and the observation of dose–response relationships suggest that they are the result of long-term pesticide exposure rather than chance alone.
Interactions of organophosphorus pesticides with solute carrier (SLC) drug transporters
Published in Xenobiotica, 2019
Lisa Chedik, Arnaud Bruyere, Olivier Fardel
The combined effects of the OPs fenamiphos and phosmet on OCT2 activity were evaluated by median drug effect analysis, as previously described (Chou, 2010). Briefly, the inhibitory effects of combinations of fenamiphos and phosmet towards OCT2-mediated transport were studied as a fixed constant ratio (1:1), chosen according to the IC50 value of each chemical, using two-fold serial dilutions with several concentration points below and above IC50 values of each OP used as a single chemical (Chou, 2010). Data from combination and single chemical effects towards OCT2 activity were then processed using the CompuSyn software (ComboSyn, Inc., Paramus, NJ), allowing thus to determine combination index (CI) values. The CI is a numerical index that is calculated using the following equation (Zhao et al., 2004): Fenamiphos/Mixture and CPhosmet/Mixture are the concentrations of fenamiphos and phosmet applied in combination to achieve × % of OCT2 activity inhibition, whereas CFenamiphos and CPhosmet represent the concentrations of individual agents to accomplish the same efficacy. Combinations were considered as synergistic when CI <0.8, additive when 0.8 ≤ CI ≤1.2 and antagonistic when CI >1.2 (Bijnsdorp et al., 2011).
Characterization of organophosphate pesticides in urine and home environment dust in an agricultural community
Published in Biomarkers, 2018
Catherine M. Tamaro, Marissa N. Smith, Tomomi Workman, William C. Griffith, Beti Thompson, Elaine M. Faustman
\Organophosphate insecticides (OPs) have been applied seasonally to apple and pear (pome fruit) orchards in the Valley and elsewhere in Washington state in order to control damaging insects such as Cydia pomenella, the codling moth (United States Department of Agriculture Washington Field Office 2006, United States Department of Agriculture 2006a). In 2005, approved agricultural uses led to the application in the Valley of approximately 86 metric tons of azinphos-methyl (AZM; trade name Guthion; Chemical Abstracts Service (CAS) No. 86-50-0), 66 metric tons of chlorpyrifos (CP; trade name Dursban; CAS No. 2921-88-2), 39 metric tons of phosmet (PH; trade name Imidan; CAS No. 732-11-6), 5 metric tons of malathion (ML; CAS No. 121-75-5) and 1 metric ton of diazinon (DZ; CAS No. 333-41-5) (Stone 2013, Thelin and Stone 2013) (Table 1).