Pyrethroid insecticides as phosphatase inhibitors

In this study we tested the hypothesis that pyrethroid insecticides inhibit calcineurin directly and that inhibition is unaffected by the immunophilin cofactors necessary for calcineurin inhibition by cyclosporin A and FK506. The type II pyrethroid insecticides cis-cypermethrin (c-Cyp), trans-cypermethrin, deltamethrin (Delt), and fenvalerate A alpha (Fen), as well as the type I pyrethroid insecticides cis- and trans-permethrin and S-bioallethrin, were unable to inhibit the phosphatase activity of purified calcineurin under conditions of maximal activation by Ca2+ and calmodulin. Furthermore, c-Cyp, Delt, and Fen did not affect the Ca2+ dependence of calcineurin at 0.1 microM of calmodulin, indicating that Ca2+ binding to calmodulin was not affected by these agents. c-Cyp, Delt, and Fen also failed to inhibit calcineurin phosphatase activity in rat brain supernatant and cultured IMR-32 cells, although potent inhibition was displayed by both cyclosporin A and FK506 in each of these systems. Neither the Ca2+-dependent nor the okadaic acid-inhibitable phosphatase activity toward a 24-amino acid 32P-phospho-peptide substrate was affected by any of the pyrethroid insecticides, indicating that neither type-1 or type-2A phosphatase nor calcineurin is inhibited by pyrethroids. To determine if these results were dependent upon experimental conditions, experiments were repeated using polyethylene glycol-treated glass tubes in place of the standard polypropylene tubes. Regardless of the type of tube, no inhibition of calcineurin by any of the pyrethroid insecticides was observed. These data indicate that the pyrethroid insecticides are not effective inhibitors of calcineurin or other phosphatases.     

植物生物碱杀虫剂研究进展

综述了植物生物碱的种类、杀虫活性、杀虫作用方式与机理,分析了其市场需求和研究开发方向.     

Estrogenic and antiprogestagenic activities of pyrethroid insecticides

Many pesticides possess hormonal activity and have thus been classified as endocrine disruptors. Pyrethroids are commonly used insecticides worldwide, but little has been done to characterize their hormone agonist/antagonist potential. We tested four frequently encountered pyrethroids, fenvalerate, sumithrin, d-trans allethrin, and permethrin, for estrogen and progesterone agonist/antagonist activities using the Ishikawa Var-I human endometrial cancer cell line and the T47D human breast cancer cell line. Both cell lines produce alkaline phosphatase as an indicator of hormonal activity. Fenvalerate and sumithrin demonstrated significant estrogenicity; at concentrations of 10 microM, these compounds achieved maximal activities comparable to that of 10 nM 17alpha-ethynylestradiol in Ishikawa Var-I cells. None of the four compounds showed statistically significant estrogen antagonist activity or acted as progestins. However, fenvalerate and d-trans allethrin significantly antagonized the action of progesterone in T47D cells. Through these hormonal pathways, exposure to certain pyrethroids may contribute to reproductive dysfunction, developmental impairment, and cancer.     

A guide to nurse prescribing of insecticides and anthelmintics

Several drug preparations are available to the nurse prescriber to treat parasitic infestations, most commonly head lice, scabies and threadworms. It is vital that the nurse has a thorough knowledge of the types of preparations available, together with an understanding of the non-pharmacological interventions to eradicate infestation. Many people may be treated without the intervention of a doctor, but the nurse prescriber should ensure that those who are affected receive appropriate referral to their GP if there are special circumstances, secondary infestation or a suspected infestation by roundworms.     

Selected pyrethroid insecticides stimulate glutamate uptake in brain synaptic vesicles

We aimed to ascertain whether pyrethroid insecticides could influence the vesicular transport of the excitatory amino acid glutamate. The incubation of rat cortical synaptic vesicles with resmethrin and permethrin, consistently stimulated both ATP-dependent and -independent uptake of [3H]glutamate, while not evoking depletion of its vesicular content. Both processes were counteracted by valinomycin, a dissipator of the transmembrane potential gradient (deltapsi(sv)). Meanwhile, the vesicular influx of 36Cl- anions was impaired by pyrethroid concentrations which did not affect the ATP-dependent uptake of [14C]methylamine, as a marker for the proton gradient (deltapH). Thus, the stimulation of glutamate transport appeared to involve mainly the deltapsi(sv). A self-attenuating effect of selected pyrethroids on putatively enhanced excitatory transmission in severe intoxication is suggested.     

Penetration of household insecticides through different types of textile fabrics

Six different types of fabrics were compared for their ability to protect against human exposure to three different commercial household aerosol insecticides. Fabrics used in this investigation were, 100% cotton, cotton-polyester thermal underwear, cotton-polyester blend (twill), 100% acrylic, 100% wool and artificial silk (rayon). The household insecticides were, Black Flag (Ant and Roach Killer), Raid (Ant and Roach Killer) and Hot Shot (Wasp and Hornet Killer) containing propoxur, permethrin/pyrethrins and chlorpyrifos/allethrins as their active ingredients respectively. A fluorescent tracer, 4-methyl-7-diethyl amino coumarin was mixed with the aerosol (or equivalent aliquot) and sprayed onto cloth squares fitted on Whatman paper patches. The percentage of penetration through the cloth was quantified by the intensity of the fluorescence spectrum of each patch extract and the amount of the tracer recovered was calculated. The extract was concentrated to 1/10th of the volume to measure the content of each of the insecticides by supercritical fluid chromatography (SFC) using electron capture (ECD) and diode array detectors. Scanning electron microscope (SEM) images of the fabrics showed the geometry of the yarn. The results obtained from the fluorescence spectra, SFC and SEM showed that cotton-polyester (twill), cotton, wool and cotton thermal underwear were the least penetrable materials for the aerosols. On the other hand, acrylic and artificial silk (rayon) were the most penetrable cloth types.     

Gas chromatographic analysis of heptafluorobutyryl derivatives of some carbamate insecticides

Erythropoietin, the hormone that regulates erythropoiesis in mammals, was 125I-labelled by using the catalytic properties of lactoperoxidase and the H2O2-generating properties of glucose oxidase. This methodology, both rapid and simple, not only produced hormone preparations with high specific radioactivity but also did not substantially alter the biological integrity of erythropoietin when it was assayed in vivo.     

Liquid chromatographic determination of five benzoylurea insecticides in fruit and vegetables

A liquid chromatographic (LC) method was developed to determine 5 benzoylureas--diflubenzuron, hexaflumuron, teflubenzuron, flufenozuron, and lufenuron--in peppers, tomatoes, eggplants, cucumbers, and oranges. Preparation of samples involve extraction with acetone and partitioning into dichloromethane-petroleum ether. A portion of this extract is cleaned up with a solid-phase extraction aminopropyl disposable column. With LC analysis using an RP-8-DB microbore column, acetonitrile-water (70 + 30, v/v) as mobile phase, and photodiode array detection at 254 nm, recovery and repeatability data were collected for the 5 benzoylureas on 4 vegetables and citrus in the range 0.04-2.0 mg/kg. Validated limits of detection and quantitation were 0.01 and 0.04 mg/kg, respectively. The method is reliable for routine analysis of vegetables and fruits.     

Study of the sensitivity of Anopheles to insecticides in northeastern Afghanistan

Two unusual anaerobic vibrio-like organisms were recovered from blood cultures of two patients. One isolate was identified as Desulfovibrio desulfuricans. It appeared to be the cause of a 24-h episode of fever, chills, and profuse perspiration. This is apparently the first documented report of human infection due to this organism. The second isolate was a Succinivibrio species. It has rarely been described as a cause of bacteremia. The clinical significance of the organism remains unclear.     

Molting hormonal and larvicidal activities of aliphatic acyl analogs of dibenzoylhydrazine insecticides

Dibenzoylhydrazines are the nonsteroidal ecdysone agonists. Using comparative molecular field analysis, we previously found that the alkyl side chain of 20-hydroxyecdysone (20E) is three-dimensionally superposable with one of their two aryl moieties. To identify the aryl moiety that is better superposable on the alkyl chain, we synthesized compounds in which one of the two aryl groups of tebufenozide (N-t-butyl-N-3,5-dimethylbenzoyl-N'-4-ethylbenzoylhydrazine) is replaced by alkyl groups such as C4H9, C5H11, and C6H13. The molting hormonal activity of these compounds was measured using cultured integuments prepared from rice stem borers, Chilo suppressalis Walker, in terms of stimulation of incorporation of N-acetyl-[14C]glucosamine. N-t-Butyl-N-3,5-dimethylbenzoyl-N'-acylhydrazines with a hexanoyl or heptanoyl group were about 20-fold higher than that of 20E, whereas N-acyl-N-t-butyl-N'-4-ethylbenzoylhydrazines with a hexanoyl or heptanoyl group were much weaker than 20E. Their larvicidal activity was also measured against rice stem borers. The former series of compounds were much more active than the other series as well as 20E. Thus, the benzoyl moiety of dibenzoylhydrazines, which is bound to the secondary nitrogen atom (-NH-), is replaceable by aliphatic acyl groups without greatly affecting the biological activities.     

Monitoring of organophosphorus insecticides in the Guadalete River (southern Spain)

Electrophysiologic monitoring of head-injured patients, using electroencephalogram (EEG) and sensory-evoked potentials, can provide a functional assessment of the neural structures involved in tested pathways. Experience using EEG, somatosensory-evoked potentials, brainstem auditory-evoked potentials, visual-evoked potentials, and the combination of sensory-evoked potentials termed multimodality-evoked potentials as clinical tools to augment patient evaluation and predict outcome demonstrates that these methods can be effectively integrated into clinical care. They can be used to augment the neurologic examination and provide useful information when other measures of neural function are limited by deep coma or by other treatment modalities that confound the clinical examination.     

Multiresidue determination of insecticides and fungicides in fruits and vegetables by gas chromatography

In clinical observation on 248 patients with breast cancer IIb-III-b stages given radiotherapy on breast gland, parasternal and axillary-subclavian regions (total doses 40 Gr for each) before mastectomy was shown, that use LF im 2-3 times a week through the course of therapy decreases statistically significant pancytopenia, induced by radiation. Quantity leukocytes was even increase in a process of therapy. Frequency of anemia and lyphopenia was decreased almost 3 times. E-RFC were depressed also more slight, then in the group without immunocorrection and after mastectomy practically, restored. IFN-gamma production by T-lymphocytes was not changed and essentially more high then in the comparative group. The presented data are shown, that LF provides a defensive action on hematological indices and immune effectors function in oncological patients during radiotherapy.