Levels of dichlorodiphenyltrichloroethane and deltamethrin in humans and environmental samples in malarious areas of Mexico

Mexico used dichlorodiphenyltrichloroethane (DDT) to control malaria until 1999, when it was replaced with deltamethrin for mosquito control. Thus, we performed environmental and exposure assessments to DDT and deltamethrin in the states of Chiapas and Oaxaca. In Chiapas, samples were obtained at the time when DDT was being used in the malaria control program, while in Oaxaca, samples were collected 2 years after the final spraying of DDT and 2 days after deltamethrin application. Mean concentrations of DDT and Dichlorodiphenyldichloroethylene (DDE), as measured in whole blood, were 67.8 and 86.7 microg/L for children living in Chiapas and 27.1 and 60.8 microg/L for adults, respectively. As expected, DDT levels were lower 2 years after the final application in Oaxaca (20.4 and 13.2 microg/L for children and adults, respectively). Sprayers in Chiapas had the highest levels of exposure, with 165.5 and 188.4 microg/L of DDT and DDE, respectively. Women living in Chiapas and Oaxaca also had significantly higher blood levels of DDT and DDE than those women living in areas where less DDT had been used. Deltamethrin exposure was assessed only in children living in Oaxaca; 50% of the exposed group had urinary levels of 3-phenoxybenzoic acid above the limit of detection (LOD) and 6% had levels above 25 microg/L (five times the LOD), with a negative trend with age (r=-0.33). In Chiapas we found higher DDT and DDE levels in soil than in Oaxaca. In the latter location, large amounts of DDT and DDE were found in sediment samples and deltamethrin was detected in indoor soil samples. Considering the environmental data, the blood level results can be explained by soil/dust ingestion, human milk ingestion, and consumption of fish and other contaminated foods.     

河南信阳中华按蚊对3种杀虫剂的敏感性调查

目的了解信阳地区主要传疟媒介中华按蚊药物敏感性状况,为制定防治策略提供依据。方法WHO推荐的成蚊滤纸接触筒法,用溴氰菊酯(0.05%)、DDT(4%)、马拉硫磷(5%)3种药纸对中华按蚊雌性成蚊进行测试。结果信阳9县区中华按蚊对溴氰菊酯、DDT、马拉硫磷的死亡率(或校正死亡率)范围分别为22.22%~100%、11.11%~100%、25.33%~100%;不同县区中华按蚊对同一杀虫剂的抗性级别均有从敏感群体(S)到抗性群体(R)的分布;9县区中华按蚊对溴氰菊酯、DDT的首只击倒时间范围为1.0~23.78min、0.5~53.67 min,60 min击倒率范围为3.92%~75%、3.96%~95.05%,KT50范围为42.02~1 459.54min、35.23~1 459.54 min。结论信阳地区9县区中华按蚊对3种杀虫剂敏感性不全相同,存在地域差异。     

Deltamethrin induced an apoptogenic signalling pathway in murine thymocytes : exploring the molecular mechanism

Deltamethrin (DLM) is a well‐known pyrethroid insecticide; however, the immunotoxic effects of DLM on the mammalian system and its mechanism is still unclear. This study has been designed to first observe the binding affinity of DLM to immune cell receptors and its effects on the immune system. The docking score revealed that DLM has a strong binding affinity towards the CD4 and CD8 receptors. DLM induces apoptosis in murine thymocytes in a concentration‐dependent manner. The ear\ly markers of apoptosis such as enhanced reactive oxygen species (ROS) and caspase‐3 activation are evident as early as 1 h by 25 and 50 μM DLM. Glutathione (GSH) depletion has also been observed at 1 h by 50 μM DLM concentration. In cell‐cycle studies using flow cytometry, the fraction of hypodiploid cells has gradually increased with all the concentrations of DLM at 18 h. The Annexin V binding assay measures the effect of DLM on apoptotic and necrotic cells. The apoptotic cells raised from 18.6% to 35.21% (10–50 μM DLM) at 18 h. N‐acetyl cysteine (NAC) effectively reduced the percentage of apoptotic cells which is increased by DLM. In contrast, buthionine sulfoximine (BSO) caused an elevation in the percentage of apoptotic cells. These results demonstrate that caspase activation, ROS activation and GSH act as critical mediators in a DLM‐induced apoptogenic signalling pathway in murine thymocytes. In the presence of caspase inhibitor, the percentage of apoptotic cells is partially decreased. Thus, there may be the possibility of some other caspase‐independent pathways in DLM‐induced apoptosis. Copyright © 2013 John Wiley & Sons, Ltd.     

地震后临时居住地蝇类防治效果观察

目的采用溴氰菊酯控制蝇类密度,预防地震后肠道传染病的暴发流行。方法使用了空间喷雾与滞留喷洒相结合的实验组与对照组的对比实验。结果采用0．05％溴氰菊酯每天喷洒厕所、垃圾集中点、生活污水排放处,持续6d,对照组与实验组经统计学处理（P〈0．05）,均有显著差异;入住帐篷和厨房内滞留喷洒溴氰菊酯,帐篷内药效可持续7d,厨房内仅持续4d,对照组与实验组经统计学处理（P〈0．05）,有显著性差异。结论溴氰菊酯空间喷雾和滞留喷洒均能有效降低蝇类密度。     

新型卫生杀虫剂的研制及其药效观察

目的研制高效低毒卫生杀虫剂。方法在实验室筛选最佳配比,研究其理化性质及毒理、毒力的变化,并进行灭效观察。结果最佳复配比例为10∶1,对家蝇幼虫的共毒系数为279.8,增效倍数为4.48;2.5%速灭蝇溴乳油对哺乳动物低毒;在不同面板上药效滞留时间达75 d以上;对蝇类的现场杀灭效果在90%以上。结论速灭蝇溴乳油高效低毒,经济有效,适于在基层部队推广应用。     

药物浸泡蚊帐对蚊虫的杀灭效果研究

目的在实验室内观察微胶囊防蚊整理剂浸泡蚊帐对淡色库蚊的杀灭效果。方法强迫接触方法及蚊帐直接接触方法。结果使用微胶囊防蚊整理剂浸泡蚊帐,连续90 d进行调查观察,药物蚊帐在30、60、90 d后对淡色库蚊的杀灭率分别为90%、80%和70%,经过常规洗涤后,其效果下降不明显。使用溴氰菊酯作为防蚊整理剂比高效氯氰菊酯防蚊灭蚊效果好,2种剂型90 d有效保护率均在70%以上。结论使用微胶囊防蚊整理剂浸泡蚊帐具有良好的灭蚊效果,能够有效地控制蚊虫密度,减少蚊虫对人的叮咬,降低疟疾等媒介疾病的发生。     

Chlorella vulgaris ameliorates testicular toxicity induced by deltamethrin in male rats via modulating oxidative stress

This study was carried out to investigate the potential effects of Chlorella vulgaris (CV) on testicular function and oxidant/antioxidant status in normal and deltamethrin‐intoxicated rats. Forty adult male rats were drenched either with normal saline, CV (50 mg/kg), deltamethrin (DM) (3 mg/kg), or CV combined with DM, daily for 8 weeks. At the end of the protocol, the epididymal sperm quality was evaluated and the testicular superoxide dismutase (SOD), catalase enzyme (CAT) and malondialdehyde (MDA), and the serum testosterone levels were estimated. Normal rats treated with CV showed a significant increase in the total sperm number/epididymal tail, testicular SOD, and CAT levels with a significant decrease in the testicular MDA. Deltamethrin intoxication significantly decreased the proportions of motile and live sperm, the testosterone concentration, the testicular SOD and CAT levels, whereas it significantly increased the proportion of abnormal sperm and the testicular MDA. Chlorella vulgaris treatment significantly ameliorated the adverse effects of DM‐intoxication and restored most of the parameters to levels that are comparable to those of the control group. In conclusion, CV administration improved the testicular function of normal rats and ameliorated the effect of severe oxidative stress conditions.     

溴氰菊酯致大鼠胃黏膜慢性损伤的观察

目的探讨溴氰菊酯中毒对大鼠胃黏膜的慢性病理损伤及其机制。方法染毒组大鼠分别给予不同剂量溴氰菊酯灌胃;对照组即橄榄油组仅给予相同剂量橄榄油。肉眼观察各组大鼠胃黏膜的大体损伤情况;取胃体部组织,制成切片,苏木精-伊红染色,镜下观察胃黏膜损伤情况,并对损伤程度进行累计积分;观察胃底腺的形态结构,计数壁细胞的数量。结果镜下对照组大鼠胃黏膜结构完整,胃底腺排列紧密规则,壁细胞形态结构较正常,无炎性细胞浸润。染毒组大鼠与对照组大鼠相比较,胃黏膜均呈现不同程度的损伤。高剂量组大鼠胃黏膜慢性病理损伤积分与其余各组比较差异有显著性(F=10.65,q=4.81～7.49,P<0.05);高剂量组大鼠胃黏膜壁细胞数量较对照组明显增多,差异有显著性(F=5.11,q=5.04,P<0.05)。结论溴氰菊酯对大鼠胃黏膜有较明显的慢性病理损伤的作用,尤其对胃底腺壁细胞的影响较为明显,损伤的机制可能与胃黏膜屏障功能的破坏和胃肠神经递质的变化有关。     

Multidrug resistance protein gene expression in Trichoplusia ni caterpillars

Many insect species exhibit pesticide‐resistant phenotypes. One of the mechanisms capable of contributing to resistance is the overexpression of multidrug resistance (MDR) transporter proteins. Here we describe the cloning of three genes encoding MDR proteins from Trichoplusia ni: trnMDR1, trnMDR2 and trnMDR3. Real‐time quantitative PCR (qPCR) detected trnMDR mRNA in the whole nervous system, midgut and Malpighian tubules of final instar T. ni caterpillars. To test whether these genes are upregulated in response to chemical challenge in this insect, qPCR was used to compare trnMDR mRNA levels in unchallenged insects with those of insects fed the synthetic pyrethroid, deltamethrin. Only limited increases were detected in a single gene, trnMDR2, which is the most weakly expressed of the three MDR genes, suggesting that increased multidrug resistance of this type is not a significant part of the response to deltamethrin exposure.