Spatial distribution of lindane in topsoil of Northern France

Lindane is a persistent organochlorine insecticide and the use of this insecticide in agriculture was banned in France in 1998. In this study we investigated the concentrations of lindane in topsoil in Northern France and used robust geostatistics to map the geographical distribution of lindane. The study was based on a 16 km × 16 km grid covering an area of ca 25 000 km². Lindane was found in all soils, even those from non-agricultural-application areas. Very low ratios of α-/γ-HCH and δ-/γ-HCH suggested that a long time had passed since technical HCH was used in the studied area, or that emission sources of lindane were still present. A strong gradient in lindane concentration was observed, with the highest lindane concentrations in an area located in the northern region. Results suggested that some of the lindane observed in the high concentration area may have come from volatilization of old lindane applied to intensively cultivated areas, which was then transported by prevailing winds coming from the south-west and deposited in a densely inhabited depression.     

Triadimefon Causes Branchial Arch Malformations in Xenopus laevis Embryos (5 pp)

- DOI: http://dx.doi.org/10.1065/espr2006.01.014 Background, Aims and Scope Triazole-derivatives are potent antifungal agents used as systemic agricultural fungicides and against fungal diseases in humans and domestic animals. They act by inhibiting the cytochrome P-450 conversion of lanosterol to ergosterol, thus resulting in faulty fungal cell wall synthesis. Some data have been published about the teratogenic activity of triazoles on rodent embryos: Hypoplasias, abnormal shape, agenesis of the branchial arches, for example, were reported as typical induced malformations. Unfortunately, no data are available on the embryotoxicity of these compounds in amphibians, despite the increasing concern among the scientific community about the phenomenon of global amphibian population declines. The aim of the present work is to evaluate the embryo-lethal and teratogenic potentials of Triadimefon (FON), a triazolederivative widely used as an antimycotic in agriculture, by the test FETAX (Frog Embryos Teratogenic Assay, Xenopus) with particular attention being paid to the analysis of branchial arch malformations. Methods Xenopus laevis embryos were exposed continuously from stage 9 to increasing concentrations of FON and analyzed at stage 47 for mortality and teratogenicity (group I) to determine the median lethal (LC50) and teratogenic (TC50) concentrations. Another two pools of larvae were exposed to FON for a 2 hour period at early gastrula (Group II) or neurula (Group III) stages to verify which period of development is the most sensitive to FON. The malformations observed were further investigated by histological section and cartilage staining with Alcian blue. Results and Discussion The assay has estimated LC50 and TC50 values of 63.8 μM and 2.73 μM, respectively; the resulting TI (Teratogenic Index = LC50/TC50) value of 23.4 has underlined the very high teratogenic risk associated with this compound. Neurulation was more sensitive to FON exposure than gastrulation, since the TC50 estimated values for group III (neurula exposed) specimens was 7.6 times lower than those of group II (gastrula exposed). Interestingly, for each group analyzed, 100% of malformed embryos showed alterations at branchial arch derived cartilages: Anterior cartilages were reduced, missing, fused or incorrectly positioned while gill cartilages were altered only in the most severely affected specimens. In some cases these malformations were associated with hyperpigmentation. Our results support the hypothesis that FON can interfere with Neural Crest Cell (NCC) migration, since craniofacial components and melanophores are derived from neural crest material. Conclusion In conclusion, our data show Triadimefon to be a potent teratogen able to induce specific craniofacial malformation in Xenopus laevis embryos, probably interfering with the NCC migration into the branchial mesenchyme. These results are also interesting for ecotoxicological reasons as FON, as well as other pesticides, are likely to be present in water systems near agricultural or urban areas which may serve as habitats for developing amphibians and fishes. Recommendation and Outlook Our results are in agreement with the data obtained on in vitro cultured rat embryos suggesting that the FON mechanism of action involves strongly conserved molecules. The choice of Xenopus laevis as the model organism allows us to extend the toxicological and teratological observations to a molecular level, in order to search for novel genes regulated by FON exposure.     

Psychological consequences of prenatal diagnosis in a case of familial Angelman Syndrome

Angelman Syndrome (AS), characterized by mental retardation, absence of speech, seizures and motor dysfunction, is caused by genetic defects leading to loss of expression of the maternal copy of the chromosome 15q11–13 imprinted region. Most cases are sporadic, being caused by de novo deletion of maternal chromosome 15q11–13 (75%) or by paternal uniparental disomy (3–4%). Familial cases can occur, due to mutations in the UBE3A gene or in the imprinting center. We describe the case of a pregnant woman having two nephews with AS caused by a UBE3A mutation; lack of communication within the family led the woman to be completely unaware of the risk of disease recurrence until 15 weeks of gestation. UBE3A genetic testing revealed she carried the familial mutation 892–893delCT. Prenatal diagnosis was performed on amniotic fluid and demonstrated that the fetus had inherited the mutation. The unexpected diagnosis and the subsequent termination of the pregnancy caused the woman to undergo acute psychological distress showing relevant psychopathological symptoms. Nevertheless, at 2-year follow-up, adverse consequences were minimized, and the couple was planning a new pregnancy. Factors affecting the psychological outcome of abortion and the role of psychological support in reducing the risk of long-term unfavorable consequences are discussed. Copyright © 2006 John Wiley & Sons, Ltd.     

Detection of infectious parasites in reclaimed water.

The presence of infectious protozoan pathogens in reclaimed water may present an unacceptable health risk. This study was designed similar to a study reported by Garcia et al. (2002), which detected no infectious Giardia cysts in the final effluent of a tertiary treatment facility as determined by animal infectivity (dose 1000 cysts/gerbil). This study also included evaluation of Cryptosporidium oocyst infectivity. Infectious Giardia cysts were detected in the final effluent with 1 gerbil out of 3 inoculated with 250 cysts from reclaimed water showing signs of infection 15 days postinoculation. None of the Cryptosporidium oocysts concentrated from the reclaimed water samples appeared to be infectious.     

Umbilical artery velocity waveforms before and after chorionic villus sampling

Because a vascular aetiology has been suggested for the limb and oromandibular defects described after chorionic villus sampling (CVS), to determine whether transabdominal (TA) CVS causes noticeable changes in umbilical artery velocity waveforms in first-trimester pregnancies, the pulsatility index (PI) of the umbilical artery was evaluated before and after TA-CVS in 175 pregnancies sampled between 10·0 and 13·0 weeks' gestation. In 139 uncomplicated pregnancies, the mean PI values (with 95 per cent confidence interval) were before TA-CVS 2·751 (2·692–2·809), after 10 min 2·723 (2·697–2·809), and after 1 h 2·781 (2·722–2·840). There were no significant changes in PI relative to the CVS procedure either in pregnancies with an abnormal result or in those ending in spontaneous abortion. Our data do not support any statistically significant change in umbilical artery PI relative to TA-CVS in first-trimester pregnancies. This procedure, despite its invasive character, does not appear to affect the feto-placental circulation.     

巴西亚马孙河流域雅诺马马人体内的有机汞含量

位于巴西北部的Catrimani河流域是雅诺马马人的居住地,且自1980年以来,一直是采金场所.金矿开采活动释放入环境中的无机汞会被转化为有机汞,且在水域生态系统会发生生物放大作用.摄食被汞污染鱼的人群,如雅诺马马人有可能会受到危害.我们分别于1994年和1995年对居住在采矿河流附近和非采矿河流附近的雅诺马马村民进行了调查,并且对被其捕捞的水虎鱼体内的汞含量进行了分析.我们分别于1994和1995年对5个村庄的90名雅诺马马印地安人和3个村庄的62名雅诺马马印地安人进行了调查研究.于1994年所调查的5个村庄中,有4个位于Catrimani河沿岸,大约在距过去金矿开采活动场所下游140～160km处.另一个村庄位于没有开采活动的ajaraní河沿岸.于1995年所调查的3个村庄中,有两个位于Catrimani河沿岸的村庄再一次被调查,另一个位于没有采矿活动的Pacu河.在被调查的所有村民中,其血液中有机汞含量的变化范围为0～62.6μg/L(每个村庄的平均值在21.2～43.1μg/L之间).采自有采矿活动的Catrimani河的水虎鱼汞含量的变化范围为235～1084ppb.在所测的13个水虎鱼样品中,有9个体长在30cm或更长的水虎鱼样品总汞含量超过了世界卫生组织和巴西卫生部规定的鱼中汞消费限值(500ppb).不幸的是,在没有开采活动的Ajaraní和Pacu河附近的居民和鱼体内都呈现出了较高的汞水平,这表明间接的汞源也会对亚马孙河流域造成环境污染.