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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
According to LD50 studies, which are accurate only for studies of acute exposures and, hence, invalid for approximating levels of chronic exposure, the order of descending toxicity for OPs (Figure 7.17) is tetraethyl pyrophosphate, phorate, disulfoton, fensulfothion, demeton, terbufor, meviphos, methidathion, chlormephos, sulfotep, chlorthiophos, monocrotophos, fonofos, prothoate, fenamiphos, phosfolan, methyl parathion, schradan, chlorfenvinphos, ethyl parathion, azinphos-methyl, phosphamidon, methamidophos, dicrotophos, isofenphos, bomy, carbophenothion, ethyl parathion (EPN), famphur, fenophosphon, dialifor, cyanofenphos, bromophos-ethyl, leopohos, dichlorvos, coumaphos, ethoprop, quinalphos, traizophos, demton-methyl, propetamphos, chlorpyrifos, sulprofos, dioxathion, isoxation, phosalone, thiometon, heptenophos, crotoxyphos, cythioate, phencapton, DEF, ethion, dimethoate, fenthion, dichlofenthion, and EPBP.144 Survival from these exposures can cause chemical sensitivity.
Cholinesterase Inhibitors (Anticholinesterases) And Reversal Agents
Published in Kate McCombe, Lara Wijayasiri, Paul Hatton, David Bogod, The Primary FRCA Structured Oral Examination Study Guide 2, 2017
Kate McCombe, Lara Wijayasiri, Paul Hatton, David Bogod
This class also includes: Sarin, VX – nerve gases used in chemical warfare.Tetraethyl pyrophosphate (TEPP) – an insecticide.
Insecticides
Published in Frank A. Barile, Barile’s Clinical Toxicology, 2019
Most of these compounds are dense liquids (specific gravity above 1.25) or solids at room temperature, have low vapor pressure, and are slightly soluble or insoluble in water at 20˚C. Table 28.1 outlines the physical characteristics and relative rodent toxicity of a variety of OP insecticides. The sulfur-containing compounds, such as dimethoate, require metabolic activation prior to binding to the enzymatic target. Figure 28.1 illustrates and compares the chemical structures of some of the OP compounds. Tetraethyl pyrophosphate (TEPP) is one of the more potent OP insecticides with the prototype structural features of the OP molecules. Substitution of the diethyl phosphate with the para-nitrophenyl substituent and a thiol replacement for the oxygen group renders the parathion molecule comparatively less potent and toxic. Further substitutions within the parathion molecule, as illustrated in Figure 28.1, result in the formation of malathion, a compound with much lower toxicity and of high commercial value. Structures of selective OP compounds. Structures of several selected OP molecules are shown. Blue highlight indicates structural similarities to the prototypic molecule (TEPP, tetraethylpyrophosphate).
Gadolinium-based contrast agents: in vitro paraoxonase 1 inhibition, in silico studies
Published in Drug and Chemical Toxicology, 2021
Şükrü Beydemir, Cüneyt Türkeş, Ahmet Yalçın
Living things have been intertwined with chemicals throughout their lives. These chemicals can be many different drugs and other compounds as well as water, air, and foods having vital importance. On the other hand, many toxic compounds are also encountered that living things are exposed. Among the most toxic chemicals in the world, organophosphorus compounds (OPs) are in the first order (Heath 1992). Although OPs were initially developed to be used as insecticides, they have been unfortunately used as chemical warfare agents due to their strong toxicity (Ballantyne and Marrs 2017). The most known of these are tabun, sarin, soman, and cyclosarin as well as insecticides, paraoxon, parathion, and tetraethyl pyrophosphate (Nurulain 2011). Due to effects on the nervous system of the OP chemicals, particularly irreversible inhibition of the acetylcholinesterase has been taken into account by scientists, very seriously (Silva Filho et al.2004, Saint-André et al.2011). Paraoxonase 1 (PON1), a serum enzyme, is a critical OP hydrolyzer in metabolism (Demir and Beydemir 2015, Işık et al.2015). The high-density lipoprotein (HDL) associated enzyme hydrolyzes several OPs used as insecticides particularly paraoxon, as well as nerve agents (e.g., sarin, soman, and tabun) (Costa et al.2005, Beydemir and Demir 2017, Caglayan et al.2019). PON1 containing 354 amino acids is a calcium-dependent antioxidant enzyme. It plays a role in the pathogenesis of various inflammatory diseases including diabetes, and atherosclerosis. It also protects HDL and LDL against oxidative stress (Demir and Köksal 2019, Taslimi et al.2019). Also, PON1 Q192R and M55L polymorphisms have been directly linked with the development of cancer between lung adenocarcinoma and squamous cell carcinoma tissues (Aldonza et al.2017).