Evaluation of prenatal diagnosis of limb reduction defects by a registry of congenital anomalies

Prenatal diagnosis performed by ultrasound scan is now a routine part of antenatal care in our region. How many fetal anomalies are actually detected by this procedure? We have used our registry of congenital malformations to answer this question regarding limb reduction defects (LRDs). The mean time of detection of LRDs was 26 weeks of pregnancy (range 16–32 weeks). The sensitivity of prenatal diagnosis of LRDs by ultrasonographic examination was much lower for isolated malformations (fetuses with only one anomaly) than for multiply malformed children with LRDs, 4·0 and 18·2 per cent, respectively. For all cases of LRDs, the percentage of prenatal detection was 11·5. Termination of pregnancy was performed in 6·7 per cent of the cases.     

Prenatal diagnosis of Huntington's disease (HD): Experiences with six cases and PCR

In the course of a 2-year predictive testing programme for Huntington's disease (HD), six couples from a total of 52 applicants requested prenatal testing. In each case, the pregnancy was in the first or second trimester when the couples were referred for DNA diagnosis. In five cases, exclusion testing was offered; in one case, a person at risk with an increased risk of being a gene carrier requested prenatal diagnosis. In all cases, informative markers for prenatal testing could be determined. Whenever possible, the newer technique of polymerase chain reaction (PCR) for D4S125 was applied to perform rapid prenatal diagnosis. Two couples withdrew before chorionic villus sampling was undertaken; prenatal diagnosis was completed in the remaining four cases. After exclusion testing, two pregnancies were determined to have an increased risk and two fetuses to have a low risk of being HD gene carriers.     

Cross-boundary issues for national parks: What works “on the ground”

In recent years, cross-boundary management has become an essential part of park management. In this article we compare the perspectives of managers of several US national parks to the advice on this issue presented in the published literature. Data were obtained from interviews of the superintendents, assistant superintendents and resources managers of five major western national parks and from a survey of participants in a NPS workshop attended by park superintendents, scientists, and resource managers; law enforcement personnel; and interpreters. Three themes related to boundary management were consistently stressed by park managers: (10 a lack of sufficient funds and personnel within the parks; (2) the need for reliable information on both political and natural processes; and, (3) the importance of personal interactions between park staff and individuals from the surrounding area. Basic data collection, the documentation of trends, cooperative groups and personal contacts, educational programs, and land acquisition were the most useful strategies. A lack of funds and information, ineffective communication, enforcement problems, and a lack of motivation for parties to reach a negotiated agreement were the most serious obstacles. A wide range of valuable institutional knowledge concerning boundary management exists within the National Park Service; however, there appears to be a gap between published strategies and the approaches that work “on the ground”.     

Use of remote sensing for the characterization of the Mediterranean coastal environment—the case ofPosidonia oceanica

The beds ofPosidonia oceanica, a marine vascular plant species endemic to the Mediterranean, form a major Mediterranean marine ecosystem. These beds are well-developed along the sandy east coast of Corsica, where the continental shelf is wide and extends for ca. 100 km. The upper limit of this ecosystem has been mapped by means of a computer image processing technique using 1/20 000 colour photographs. One of the major problems for image processing in the marine environment is the impact of the water layer (of variable thickness and quality), which can result in variations of the spectral signature for a particular vegetation or bottom type. In an attempt to reduce the impact of this artefact, a processing technique that takes into account bathymetric factors has been tested. Cartographical data obtained for an area extending from Bastia to Solenzara are presented. In the vicinity of the mouths of coastal rivers, a systematic indentation of the upper limit of the seagrass beds has been revealed. On the basis of these results, local variations in the quality of the marine environment can be detected, in particular with regard to salinity, turbidity and/or the impact of sedimentation. The overall surface area of thePosidonia oceanica beds has also been calculated.