双水平正压机在急性重度有机磷农药中毒有创通气后脱机过渡中的应用价值

目的探讨双水平正压（BiPAP）机在急性重度有机磷农药中毒（AOPP）有创通气后脱机过渡中的应用价值。方法急性重度有机磷农药中毒致呼吸衰竭患者100例,均行有创机械通气,随机分常规组（40例）和序贯组（60例）。检测两组患者心肌酶学变化,上BiPAP呼吸机前、后动脉血气,监测心率、血压、脉搏氧饱和度,并监测心率、血压、脉搏氧饱和度计算重新气管插管率。结果两组治疗后心肌酶（CK、CK—MB、AST、LDH）较治疗前均明显下降,差异有统计学意义（P〈0．01）;序贯治疗组患者拔管前及拔管2h后生命体征及动脉血气分析比较差异无统计学意义（P〉0．05）;撤机后序贯治疗组在有创通气时间、总机械通气时间、入住ICU／EICU时间明显缩短（P〈0．05）;呼吸机相关性肺炎（VAP）的发生率两组相似;序贯治疗组重新气管插管率明显低于对照组（P〈0．05）。结论患者对BiPAP呼吸机耐受性好,能够改善AOPP致中间综合征（IMS）的通气功能,并能使常规机械通气顺利脱机,减少重新插管率。     

The sea urchin embryo, an invertebrate model for mammalian developmental neurotoxicity, reveals multiple neurotransmitter mechanisms for effects of chlorpyrifos: therapeutic interventions and a comparison with the monoamine depleter, reserpine

Lower organisms show promise for the screening of neurotoxicants that might target mammalian brain development. Sea urchins use neurotransmitters as embryonic growth regulatory signals, so that adverse effects on neural substrates for mammalian brain development can be studied in this simple organism. We compared the effects of the organophosphate insecticide, chlorpyrifos in sea urchin embryos with those of the monoamine depleter, reserpine, so as to investigate multiple neurotransmitter mechanisms involved in developmental toxicity and to evaluate different therapeutic interventions corresponding to each neurotransmitter system. Whereas reserpine interfered with all stages of embryonic development, the effects of chlorpyrifos did not emerge until the mid-blastula stage. After that point, the effects of the two agents were similar. Treatment with membrane permeable analogs of the monoamine neurotransmitters, serotonin and dopamine, prevented the adverse effects of either chlorpyrifos or reserpine, despite the fact that chlorpyrifos works simultaneously through actions on acetylcholine, monoamines and other neurotransmitter pathways. This suggests that different neurotransmitters, converging on the same downstream signaling events, could work together or in parallel to offset the developmental disruption caused by exposure to disparate agents. We tested this hypothesis by evaluating membrane permeable analogs of acetylcholine and cannabinoids, both of which proved effective against chlorpyrifos- or reserpine-induced teratogenesis. Invertebrate test systems can provide both a screening procedure for mammalian neuroteratogenesis and may uncover novel mechanisms underlying developmental vulnerability as well as possible therapeutic approaches to prevent teratogenesis.     

Genotoxicity of wastewaters used for irrigation of food crops

In most towns of India, wastewater coming from both industrial and domestic sources and without any treatment is used to irrigate the agricultural crops. This practice has been polluting the soil, and pollutants could possibly reach the food chain. For the above reasons, the wastewaters of Ghaziabad City (India), which is used for irrigation, were sampled (at two different sites) and monitored for the presence of genotoxic agents from January 2005 to June 2007. Gas chromatographic analysis showed the presence of certain OC (DDE, DDT, Dieldrin, Aldrin, and Endosulfan) and OP (Dimethoate, Malathion, Methlyparathion, and Chlorpyrifos) pesticides in both the sampling sites. Wastewater samples were concentrated using XAD resins (XAD-4 and XAD-8) and liquid-liquid extraction procedures, and the extracts were assayed for genotoxic potential by Ames Salmonella/microsome test, DNA repair defective mutants, and bacteriophage lambda systems. The test samples exhibited significant mutagenicity with TA98, TA97a, and TA100 strains with the probable role of contaminating pesticides in the wastewater. However, XAD-concentrated samples were more mutagenic in both sites as compared to liquid-liquid-extracted samples. The damage in the DNA repair defective mutants in the presence of XAD-concentrated water samples were also found to be higher to that of liquid-liquid-extracted water samples at the dose level of 20 muL/mL culture. All the mutants invariably exhibited significant decline in their colony-forming units as compared to their isogenic wild-type counterparts. The survival was decreased by 81.7 and 75.5% in polA(-) strain in site I, and 76.0 and 73.5% in site II in polA(-) under the same experimental conditions after 6 h of treatment with XAD-concentrated and liquid-liquid-extracted samples, respectively. A significant decrease in the survival of bacteriophage lambda was also observed when treated with the test samples.     

Plant-derived human butyrylcholinesterase, but not an organophosphorous-compound hydrolyzing variant thereof, protects rodents against nerve agents

The concept of using cholinesterase bioscavengers for prophylaxis against organophosphorous nerve agents and pesticides has progressed from the bench to clinical trial. However, the supply of the native human proteins is either limited (e.g., plasma-derived butyrylcholinesterase and erythrocytic acetylcholinesterase) or nonexisting (synaptic acetylcholinesterase). Here we identify a unique form of recombinant human butyrylcholinesterase that mimics the native enzyme assembly into tetramers; this form provides extended effective pharmacokinetics that is significantly enhanced by polyethylene glycol conjugation. We further demonstrate that this enzyme (but not a G117H/E197Q organophosphorus acid anhydride hydrolase catalytic variant) can prevent morbidity and mortality associated with organophosphorous nerve agent and pesticide exposure of animal subjects of two model species.     

First Ecotoxicological Assessment Assay in a Hydroelectric Reservoir: The Lake Taabo (Côte d’Ivoire)

Organochlorine pesticides (OCPs) contamination was assessed in marketable species, two fishes (tilapia and catfish) and a prawn from the Lake Taabo (Côte d’Ivoire). Lindane and endosulfan were the main contaminants, suggesting their current use. DDT, endrin, heptachlor plus traces of chlordane, aldrin and fipronil were also detected. In fishes and in prawns, enzymatic biomarkers exhibited significant correlations with OCPs levels, showing the feasibility of a biomonitoring. The transfer of OCPs along the aquatic food web and their immunosuppressive effects in human are discussed. This preliminary study highlights that the pesticide contamination was concomitant with the increase in infectious diseases in the bordering population of this African lake.     

Organochlorine pesticides in commercial marine fishes of Coimbatore, India and their suitability for human consumption

Organochlorine pesticide residues were determined in 10 species of fishes caught at Cochin and Rameshwaram coast, and sold in Coimbatore, Tamil Nadu, India. Species were selected on the basis of their regular availability throughout the year and commercial value. A total of 389 fishes were analyzed for organochlorine residues and their suitability for human consumption was evaluated. Results show varying levels of residues of hexachlorocyclohexane (HCH), DDT, heptachlor epoxide, endosulfan and dieldrin. Among the 10 species, high concentration of pesticide residues were recorded in Sardinella longiceps, Carangoides malabaricus, Chlorophthalmus agassizi, Saurida tumbil and Rastrelliger kanagurta. The variation in total organochlorine residues among species and between places was not significant (P>0.05). Only five species of fishes showed monthly variation in residue levels and there was no significant correlation between the body size and residue levels in the tissue. About 22% of the fishes exceeded the maximum residue limits (MRL) of total HCH prescribed by FAO/WHO for fish products. The calculated dietary intake of total HCH through consumption of C. malabaricus, C. agassizi and S. longiceps exceeded the maximum acceptable dietary intake (ADI) limits prescribed for human consumption. The present study recommends continuous monitoring of environmental contaminants in marine fishes to assess the possible impact on human health.     

Residential proximity to agricultural pesticide applications and childhood acute lymphoblastic leukemia

Ambient exposure from residential proximity to applications of agricultural pesticides may contribute to the risk of childhood acute lymphoblastic leukemia (ALL). Using residential histories collected from the families of 213 ALL cases and 268 matched controls enrolled in the Northern California Childhood Leukemia Study, the authors assessed residential proximity within a half-mile (804.5 m) of pesticide applications by linking address histories with reports of agricultural pesticide use. Proximity was ascertained during different time windows of exposure, including the first year of life and the child's lifetime through the date of diagnosis for cases or reference for controls. Agricultural pesticides were categorized a priori into groups based on similarities in toxicological effects, physicochemical properties, and target pests or uses. The effects of moderate and high exposure for each group of pesticides were estimated using conditional logistic regression. Elevated ALL risk was associated with lifetime moderate exposure, but not high exposure, to certain physicochemical categories of pesticides, including organophosphates, chlorinated phenols, and triazines, and with pesticides classified as insecticides or fumigants. A similar pattern was also observed for several toxicological groups of pesticides. These findings suggest future directions for the identification of specific pesticides that may play a role in the etiology of childhood leukemia.     

Developmental Changes in PON1 Enzyme Activity in Young Children and Effects of PON1 Polymorphisms

Background

Paraoxonase 1 (PON1) is an enzyme that detoxifies activated organophosphorus pesticides (OPs) and is also involved in oxidative stress pathways.

Objectives

PON1 activity in newborns is lower than in adults, but the ontogeny of PON1 activity is poorly characterized in young children. We examined the effects of age and PON1 genotype on enzyme activity in a birth cohort of Mexican-American children.

Methods

We determined three substrate-specific measures of PON1 activity in 1,143 plasma samples collected longitudinally from 458 children at five time points from birth through 7 years of age, and genotyped PON1 polymorphisms at positions 192 and –108 in these children.

Results

Contrary to previous reports that PON1 activities plateau by 2 years of age, we observed an age-dependent increase in all three PON1 measures from birth through 7 years of age (p < 0.0001). The PON1₁₉₂ genotype significantly modified the effect of age on paraoxonase (POase) activity (p < 0.0001) such that increases in enzyme activity with age were influenced by the number of R alleles in a dose-dependent manner. Children with the PON1_-108CC192RR diplotype had significantly higher mean PON1 activities and also experienced steeper increases of POase activity over time compared with children with the PON1_-108TT192QQ diplotype.

Conclusions

Lower levels of the PON1 enzyme, which is involved in protection against OPs and oxidative stress, persist in young children past 2 years of age through at least 7 years of age. Future policies addressing pesticide exposure in children should take into account that the window of vulnerability to OPs in young children may last beyond infancy.     

广州郊区菜地、果园、稻田有机氯农药残留特征初步研究

目的 研究广州郊区菜地、果园、稻田土壤中有机氯农药残留特征.方法 于2008年8月采集广州市白云、从化、增城、番禺、南沙5个区域的菜地、果园、稻田0～20cm表层土壤样品.对白云和番禺两个采样点增加采集20～40 cm和40～60 cm两个剖面的土壤样品,采用气相色谱-电子捕获检测器法(GC-ECD)检测17种有机氯农药.结果 表层土壤17种有机氯农药检出率为90.59%,其残留量范围为4.19～39.89 ng/g;剖面土壤17种有机氯农药检出率为76.70%,其残留量范围为2.35～91.26ng/g.有机氯农药(OCPs)主要残留物是六六六类(HCHs)和滴滴涕类(DDTs).结论 有机氯农药检出率较高,白云和番禺的菜地20～40 cm剖面土壤OCPs超标,对土壤环境有一定危害.

Abstract：

Objective To analyze the characteristics of of organochlorine pesticides (OCPs) residues in the soil of the suburbs of Guangzhou.Methods In Baiyun,Conghua,Zengcheng,Panyu,Nansha,surface soil(0-20 cm)samples of vegetable fields,orchard and paddy soil were collected,soil profile(20-40cm,40-60cm)of Baiyun and Panyu were also collected,in Aug,2008.Gas chromatography-electron capture detector method(GC-ECD)was used to determine 17 kinds of organochlorine pesticides.Results The detection rate of 17 kinds of organochlorine pesticides was 90.59%in topsoil,the residue level was4.19-39.89 ng/g,and the detection rate in profiles soil was 76.70%,the residue level was 2.35-91.26 ng/g.OCPs residues were mainly HCHs and DDTs.Conclusion Detection rate of organochlorine pesticides is high in soil in the investigated soil and in the 20-40 cm profiles of Baiyun and Panyu,the level of OCPs exceeds the related standard limit,which may have adverse effects on soil environment.