Disease relevance of Pyrethroids

• Both these enzymes could be used as preliminary tools in establishing the relative toxicity of new pyrethroids [1].
• Ciguatoxin stimulates 22Na+ entry through the voltage-dependent Na+ channels of neuroblastoma cells and rat skeletal myoblasts when it is used in synergy with veratridine, batrachotoxin, pyrethroids, sea anemone, or scorpion toxins [2].
• Occupational exposure to pyrethroids frequently leads to paresthesia and respiratory irritation, which are probably due to repetitive firing of sensory nerve endings [3].
• Retroviruses under editing crossfire: a second member of the human APOBEC3 family is a Vif-blockable innate antiretroviral factor [4].
• Programmed neuronal death in sepsis: caught in a crossfire or a planned sacrifice [5]?

Psychiatry related information on Pyrethroids

• All pyrethroids, regardless of structural class, produced dose-dependent decreases in motor activity [6].
• The toxicity of penncapthrin and penncap-m toward D. pulex was difficult to determine because of frequent control mortality due to food deprivation resulting from the need to run tests for longer than 48 h [7].

High impact information on Pyrethroids

• It is now well established that severe neurological symptoms of poisoning with pyrethroids and DDT in mammals and insects are the result of modification of Na+ channel activity [8].
• The binding occurs on the Na+ channel at a binding site distinct from that of other gating system toxins like batrachotoxin, veratridine, grayanotoxin, aconitine, and pyrethroids [9].
• Although the use of pyrethroids is increasing, the specific enzymes involved in the hydrolysis of these insecticides have yet to be identified [1].
• A second carboxylesterase gene (NCBI accession number NM_133960), isolated during a cDNA mouse liver library screening, was also found to hydrolyze pyrethroids [1].
• The synthetic pyrethroids offer many advantages for veterinary and public health use, particularly their selectivity, high toxicity to insects, and relative lack of chronic effects [10].

Chemical compound and disease context of Pyrethroids

• Employing a mineral salts medium containing Tween 80 as the primary carbon source, a strain of Bacillus stearothermophilus was isolated which was able to hydrolyse selected second and third-generation pyrethroids to non-insecticidal products [11].
• Microencapsulated permethrin (penncapthrin) was evaluated under laboratory conditions for its toxicity toward several nontarget aquatic invertebrates [7].
• Piperonyl butoxide synergized pyrethroid-associated toxicity, but this effect may be difficult to interpret in the presence of OPs and pyrethroids [12].
• Toxicity of natural pyrethrins and five pyrethroids to fish [13].
• The acute toxicity of permethrin, resmethrin, and cypermethrin to four species of aquatic non-target invertebrate organisms, found in estuarine and freshwater ecosystems, was evaluated [14].

Biological context of Pyrethroids

• Since action potentials in these nerves are carried by calcium ions through TTX-insensitive voltage-gated cation channels, these findings provide evidence that pyrethroids can alter neuronal excitability through an action on voltage-sensitive channels other than the sodium channel [15].
• We demonstrate that pyrethroids, in addition to their neurotoxic effect, induce oxidative stress and lipid peroxidation in insects [16].
• Peroxidase activity of the recombinant nlgst1-1 indicated that it had a role in resistance, through detoxification of lipid peroxidation products induced by pyrethroids [17].
• Spheroids were left intact for different time periods to assess the effect of radiation crossfire on cell death [18].
• However, in extending usage to agricultural pest control, much more extensive investigations should be forthcoming from both chemical and biological aspects, since there is scant information on the fate of these pyrethroids in the environment [19].

Anatomical context of Pyrethroids

• Here, we show that an F-to-I substitution at 1519 (F1519I) in segment 6 of domain III (IIIS6) abolished the sensitivity of the cockroach sodium channel expressed in Xenopus laevis oocytes to all eight structurally diverse pyrethroids examined, including permethrin and deltamethrin [20].
• Insect neurosecretory neurons are sensitive to very low concentrations of pyrethroids, and disruption of the neuroendocrine system has been implicated as a factor contributing to the irreversible effects of pyrethroid intoxication in insects [15].
• The three pyrethroids tested all inhibited the transfer of Lucifer Yellow CH between WB-F344 rat liver epithelial cells in culture, supporting the increase of GGT-positive foci and suggesting that these substances can act as tumour promoters [21].
• Pyrethroid displacement of specific [3H]Ro5-4864 binding to rat brain membranes was investigated to further define the interaction of pyrethroids with the PTBR [22].
• The phenoxybenzyl pyrethroids also increased the spontaneous release of [3H]acetylcholine from rat brain synaptosomes, further supporting a depolarizing action of these insecticides on nerve terminal membranes [23].

Associations of Pyrethroids with other chemical compounds

• Channels were expressed in Xenopus laevis oocytes and the effects of the pyrethroids permethrin (type I) and deltamethrin (type II) on Na+ currents were investigated using voltage clamp [24].
• These results indicate the reciprocal allosteric interactions between a binding site for pyrethroids, a binding site for Ro5-4864, the GABA recognition moiety and the binding site for TBPS in the brain of trout [25].
• Results from urine samples from exposed workers suggest that this PBA immunoassay might be suitable as a monitoring tool for human exposure to pyrethroids [26].
• Among the tested pyrethroids, permethrin elicited the most pronounced induction of CYP2B1 mRNA, which exceeded maximal induction achieved by PB at concentrations approximately 10-fold higher [27].
• Several synthetic pyrethroids and the synergist piperonyl butoxide have been determined as aged residues on paddy rice by reversed-phase high-performance liquid chromatography with detection at 225 nm [28].

Gene context of Pyrethroids

• We used an existing collection of Drosophila para mutants to examine the molecular basis of targetsite resistance to pyrethroids and DDT [29].
• Histamine acted bidirectionally on STAT6, but pyrethroids inhibited the intracellular Th2-specific STAT6 more effectively in atopics than in nonatopics [30].
• In the present study we tested several pyrethroids for their ability to interact with androgen binding sites in dispersed, intact human genital skin fibroblasts and in human plasma to sex hormone binding globulin (SHBG) [31].
• However, none of the pyrethroids tested showed significant (p < 0.05) estrogenic or antiestrogenic effects (100 nM-10 microM), indicating that they do not impact on the classic hER alpha-mediated activation pathway in vitro [32].
• Pyrethroids inhibited IFN-gamma and IL-4 in both groups at around 10(-5) M [30].

Analytical, diagnostic and therapeutic context of Pyrethroids

• The abdominal nerve cords and neuromuscular preparations isolated from the crayfish are convenient materials for bioassay of certain environmental toxicants such as pyrethroids, chlorinated hydrocarbons, and other insecticides [33].
• Multi-residue matrix solid-phase dispersion method for the determination of six synthetic pyrethroids in vegetables followed by gas chromatography with electron capture detection [34].
• Determination of residues of synthetic pyrethroids in fruit and vegetables by gas - liquid and high-performance liquid chromatography [35].
• New born babies and children are often exposed to pyrethroids for long periods by the use of liquid vaporizers [36].
• PCR and sequencing was undertaken only on individuals that were demonstrated to be phenotypically nerve insensitive or susceptible to pyrethroids using a neurophysiological technique [37].

References