Positive Feedback Loop between Introductions of Non‐Native Marine Species and Cultivation of Oysters in Europe

With globalization, agriculture and aquaculture activities are increasingly affected by diseases that are spread through movement of crops and stock. Such movements are also associated with the introduction of non‐native species via hitchhiking individual organisms. The oyster industry, one of the most important forms of marine aquaculture, embodies these issues. In Europe disease outbreaks affecting cultivated populations of the naturalized oyster Crassostrea gigas caused a major disruption of production in the late 1960s and early 1970s. Mitigation procedures involved massive imports of stock from the species’ native range in the northwestern Pacific from 1971 to 1977. We assessed the role stock imports played in the introduction of non‐native marine species (including pathogens) from the northwestern Pacific to Europe through a methodological and critical appraisal of record data. The discovery rate of non‐native species (a proxy for the introduction rate) from 1966 to 2012 suggests a continuous vector activity over the entire period. Disease outbreaks that have been affecting oyster production since 2008 may be a result of imports from the northwestern Pacific, and such imports are again being considered as an answer to the crisis. Although successful as a remedy in the short and medium terms, such translocations may bring new diseases that may trigger yet more imports (self‐reinforcing or positive feedback loop) and lead to the introduction of more hitchhikers. Although there is a legal framework to prevent or reduce these introductions, existing procedures should be improved. Ciclo de Retroalimentación Positiva entre la Introducción de Especies Marinas No‐Nativas y el Cultivo de Ostras en Europa     

最高气温对呼吸系统疾病急诊人次的影响研究

采用基于时间序列的半参数的广义相加模型,在控制星期几效应、长期趋势、气象要素等混杂因素后,分析2009~2012年北京市日最高气温与四类呼吸系统疾病急诊人次的暴露-反应关系,探讨日最高气温对人群健康的影响,并考虑了不同年龄和性别人群分层以及0~6d的滞后效应.结果表明：日最高气温对呼吸系统疾病急诊存在0~1d滞后效应,男性急诊人次均要高于女性;日最高气温每上升1℃,男性上呼吸道感染和支气管炎急诊人次分别增加2.10%和2.14%,女性肺炎、哮喘和支气管炎急诊人次分别增加2.00%、4.21%和2.95%.对性别而言,日最高气温每上升1℃,小于15岁人群支气管炎急诊人次增加3.60%;15~59岁人群支气管炎急诊人次增加2.16%;对60~74岁年龄段急诊人次无显著统计学意义;≥75岁人群肺炎和哮喘急诊人次分别增加2.69%和8.05%.     

First-trimester prenatal diagnosis in twin pregnancies

Two twin pregnancies at risk for a sex-linked disorder are described. Both pregnancies were dichorionic. Transabdominal sampling was chosen for prenatal diagnosis. Molecular genetic techniques raised suspicion with regard to the accuracy of the samples in one case. Second-trimester amniocentesis confirmed the error. Selective feticide of the affected fetus was performed. When first-trimester prenatal diagnosis is offered in dichorionic twin pregnancies, confirmation through molecular genetic testing can confirm that villi have been obtained from different fetuses. All parties must be aware that additional invasive diagnostic procedures in the second trimester may be required in cases of doubt.     

Prenatal diagnosis and obstetrical management of multicystic dysplastic kidney disease

Multicystic dysplastic kidney disease (MDKD) is one of the most common congenital renal anomalies. We report 16 consecutive cases of MDKD recognized in the antenatal period by sonography. Diagnosis is usually easy as MDKD has in the vast majority of cases a striking ultrasound appearance including enlargement of the kidney and multiple renal cysts. However, differentiation from obstructive uropathy may be difficult, and we made a total of five erroneous diagnoses. Unilateral MDKD has almost invariably a good prognosis. However, severe life-threatening associated anomalies were found in six cases. Therefore, a detailed survey of fetal anatomy and determination of karyotype are strongly recommended.     

Prenatal diagnosis of cystic fibrosis: Ultrasonographic appearance of meconium ileus in the fetus

Four often fetuses carrying a risk of 1:4 for cystic fibrosis were found to have low levels of microvillar enzymes in the amniotic fluid obtained between 17 and 18 weeks' gestational age. On sonography performed prior to the amniocentesis, three fetuses showed enlarged bowel loops. At autopsy, meconium ileus was detected. Enlarged bowel loops are a sign which has not been described previously so early in pregnancies.     

广东省若干典型地方病环境地球化学病因分析

广东省是我国地方病高发省份。鼻咽癌发病率位居全国之首,肝癌发病率也大大高于全国平均水平,仅次于江苏和广西两省;地氟病也有着较广泛分布。前人尤其是流行病学工作者对广东省地方病开展了许多的医学研究,取得了一定的成果,但从环境地球化学的角度进行探讨相对不足,随着研究的深入,科学家发现地方病的发生与当地环境地球化学因素存在密切的关系,文章主要针对广东省存在的典型地方病与环境地球化学背景的关系进行探讨和研究,以期从环境地球化学角度为广东省地方病的防治工作提出新的思路。     

Fetal two-dimensional doppler echocardiography (colour flow mapping) and its place in prenatal diagnosis

One hundred and fifty fetuses between 16 and 38 weeks of gestation were studied by fetal echocardiography using colour-coded two-dimensional Doppler echocardiography. Two-dimensional, M-mode, and Doppler spectral analyses were also performed. In 14 fetuses, structural and/or functional abnormalities were detected. Abnormalities were correctly ruled out in all the other fetuses. The advantages of two-dimensional Doppler echocardiography are (1) rapid screening for flow abnormalities in the fetal heart, and thus shortening of the Doppler examination time; (2) rapid diagnosis of valvular regurgitation, valvular stenosis, and abnormal shunting of blood across the interatrial and interventricular septa; and (3) facilitation of the diagnosis of complex congenital heart defects which in certain cases is possible only by using two-dimensional Doppler echocardiography.     

Deceased co-twin as a cause of false positive amniotic fluid AFP and AChE

A pregnancy was terminated because of persistently elevated amniotic fluid AFP (+10 S.D.) and an AChE band of low intensity on gel electrophoresis. No fetal anomalies were detected by ultrasonographic examination. Autopsy revealed an apparently normal fetus of about 20 weeks gestation. Attached to the placenta was a small sac containing a fetus papyraceus co-twin of about 8–9 weeks gestation. The small deceased co-twin and its gestational sac were not detected prenatally despite multiple ultrasonographic examinations. The difficulty in the interpretation of apparently conflicting results is emphasized.