Randomized trial comparing first-trimester transcervical chorionic villus sampling and second-trimester amniocentesis

A total of 800 patients were randomized at the 9th to 11th week of pregnancy either for transcervical chorionic villus sampling (CVS) on the day of trial entry or for amniocentesis (AC) at the 16th week. The indication for fetal karyotyping was maternal age in 94 per cent of the cases; the mean maternal age was 39.2 years. An adequate sample was obtained in 98.3 per cent of the cases in the CVS group and in all cases in the AC group. Retesting was indicated in 3.3 per cent of the CVS cases. An abnormal karyotype was found in 6.1 per cent of the CV samples and in 4.5 per cent of the amniotic fluid samples. There was one false-positive chromosome result in both groups. Twelve (3.1 per cent) miscarriages occurred by the 22nd week of pregnancy in the CVS group in pregnancies intended to continue. No difference was seen between the groups for total fetal loss rates. The number of surviving infants in the CVS group was 92.2 per cent and in the AC group 91.7 per cent (rate difference 0.5 per cent (95 per cent confidence interval − 3.3 to 4.3)). In our study, both the diagnostic accuracy and the risk of fetal loss were equal in the CVS and AC groups.     

Ecological condition of forests around the eastern part of the Gulf of Finland

The effects of air pollutants on forests around the eastern part of the Gulf of Finland were studied by measurement of the sulphur and calcium content of pine needles and evaluation of the ecological conditions of pine forests. Several parameters for pine trees and their needles were chosen as well as the species composition and condition of epiphytic lichens. Very high pine needle S- and Ca-contents were measured in the vicinity of the Narva and Slantsy plants. In this region both the acid and basic pollutant load is massive, partly neutralizing each other. It is suggested that the total load will, sooner or later, cause unexpected environmental damage. Wide 'lichen desert' areas were detected around Narva and Slantsy. Near the margins of these areas extraordinary epiphytes on pines were observed namely Xanthoria parietina (L.) Th.Fr. and red-coloured green alga Trentepohlia umbrina. They are regarded as indicators of alkaline pollution. The lowest pine needle S- and Ca-contents of the study area were measured in south-eastern Finland. The condition of pine forests and their needles was, however, better on the neighbouring Karelian Isthmus although the species number of epiphytic lichens was very low and the condition of the lichens was poor. It is suggested that these most sensitive indicators of air pollutants are damaged by pollutants from St Petersburg and Narva. Vast virgin forests of the Karelian Isthmus act as pollutant sinks reducing the effect of pollutants on trees. On the Finnish side intensive forest management has been carried on for many decades making forests and trees more sensitive to pollutants.     

水环境:巴西大西洋流域盆地的人为压力和生态系统变化

发展中国家中正面临经济发展挑战的那些人口密集的流域盆地和海岸带地区可能会在各种问题上受到中度或严重的环境影响.这些由巴西东北部至南部流向大西洋海岸的汇水盆地包括广阔的气候带和多种生态系统.盆地边界以内分布着大西洋雨林、大范围的半干旱热带旱生林(caatinga)、广阔的树木及灌木林地(cerrado)、巴西6670km 海岸线的一大部分及其海洋生态系统.在过去的几十年中,这些自然资源上的人类活动不断发展.海滨化已给沿海生境及生物群落造成了沉重的负担.caatinga和cerrado中的大部分原生植被遭到了破坏,仅存留了7%的大西洋原始雨林.河口、海湾和沿海泻湖也遭到了无法恢复的破坏.土地使用、筑坝和分水等活动已成为造成生境丧失和水生生态系统改变的主要原因.尽管巴西东北部地区的干旱和东南部及南部地区的富庶和工业化之间形成明显反差,但给上述两种地区的生境和生物群落造成的影响是同样严重的.阻止环境恶化的努力没有见到效果.为此建议,应该实行将重点集中在水生生态系统完整性的一些更加综合性的环境政策,而不是把重点单独地集中在自然资源上.     

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