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Rationale and technique of malaria control
Published in David A Warrell, Herbert M Gilles, Essential Malariology, 2017
David A Warrell, Herbert M Gilles
The first useful synthetic pyrethroid came from the USA in 1969; it was given the generic name of allethrin. Allethrin has eight possible isomers, depending on the position of the hydrogen atoms on the one (cis) or other (trans) side of the cyclopropane ring.
Effects of pyrethroids on the cerebellum and related mechanisms: a narrative review
Published in Critical Reviews in Toxicology, 2023
Fei Hao, Ye Bu, Shasha Huang, Wanqi Li, Huiwen Feng, Yuan Wang
PYRs are analogs of natural pyrethrins, which are contained in the pyrethrum (Osimitz et al. 2009). Allethrin, as one of the PYRs, was first successfully commercialized and gradually accepted as early as 1953 (Gupta et al. 2013). Later, many more efficient, stable and economical PYRs with different properties were developed by chemists around the world. Up to now, a variety of PYRs have been commercialized. Due to their broad spectrum of insecticides, strong selectivity, high efficiency, low toxicity and low residue, they have rapidly developed into a new class of insecticides and become one of the most widely used pesticides in agriculture and daily life (Domingues et al. 2016). PYRs can be classified into two types based on whether they contain cyano in their structure: Type I and Type II (Abreu-Villaca and Levin 2017). Type I does not contain cyano in its molecular structure, and type II contains cyano, including deltamethrin (DM), fenvalerate and so on. Due to their greater stability in the environment, high efficiency and broad spectrum, type II PYRs are the most commonly used insecticides in general, which may also explain why the large number of toxicity studies performed on type II PYRs.
Clinical presentation of type 1 and type 2 pyrethroid poisoning in humans
Published in Clinical Toxicology, 2022
Manna Sera Jacob, Ramya Iyyadurai, Arun Jose, Jude Joseph Fleming, Grace Rebekah, Anand Zachariah, Samuel George Hansdak, Reginald Alex, Vignesh Kumar Chandiraseharan, Audrin Lenin, John Victor Peter
After recruitment, 4 ml of venous blood was collected. The serum level of the pyrethroid compounds was assessed using Shimadzu High Performance Liquid Chromatography (HPLC) with the Discovery HS C18, 5 μm 25.0 cm column. The mobile phase used was water-methanol (10:90 V/V), with a flow rate of 1 ml/min at 35 °C. For extraction of pyrethroid, the sample was mixed with 70% methanol and poured onto Sep-Pak C18 columns which were pre-treated sequentially with chloroform, methanol, methanol/water, and water. The columns were then washed with water, the pyrethroid eluted with chloroform, evaporated to dryness under a stream of N2 and then re-dissolved in methanol. The 1 mg/ml stock standards for analysis were prepared in methanol and working standards in the mobile phase. The coefficient of variation (%cv) of internal quality control (IQC) samples was ≤7.0%. The standards were procured from Sigma-Aldrich USA for cypermethrin, transfluthrin, fenvalerate, allethrin, deltamethrin, lambda-cyhalothrin, permethrin and cyclomethrin. Standards were not available for alpha-permethrin, trans-allethrin and flumethrin.
Exposure to pyrethroids induces behavioral impairments, neurofibrillary tangles and tau pathology in Alzheimer’s type neurodegeneration in adult Wistar rats
Published in Drug and Chemical Toxicology, 2022
K. A. Iteire, A. T. Sowole, B. Ogunlade
Pyrethroids, the synthetic forms of pyrethrins (insecticides derived from chrysanthemum plants extracts), are currently part of the most used pesticide globally (Jayakumar et al.2008). These agents are usually formulated with petroleum distillates and packaged in combination with synergists such as piperonylbutoxide and n- octylbicycloheptenedicarboximide (Gosselin 1984), resulting in the affinity of their absorption and ability to cross the blood- brain barrier into the Central Nervous System (CNS) (Crofton et al.1995) thereby causing neurological impairments. Pyrethroids are grouped into type I and II based on the presence or absence of a cyano-group respectively (Glickman and Casida 1982). Type I include: allethrin, tetramethrin, resmethrin, bioremethrin and permethrin; while type II Includes: cypermethrin, cyfluthrin. cyphenothrin and deltamethrin. These chemicals have been observed to be neurotoxic to insects by binding and disrupting voltage-gated sodium channels in insects (Soderlund et al.2002, Wang et al.2006). Oral administration at specific concentrations have been reported to cause neurotoxic response by inducing gliosis and neurodegeneration in the cerebrum and cerebellum of rats treated with a formulation containing three of these agents (allethrin, phenothrin and imiprothrin) as active ingredients (Igho and Afoke 2014). Similarly, adverse effects from these chemicals manifested through a number of subjective clinical symptoms and deterioration of neurocognitive performances attributable to neurodegenerative diseases (Martin et al.2017).