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Jonathan L. A. Callaway Lisa G. Shaffer Lyn S. Chitty Jill A. Rosenfeld John A. Crolla 《黑龙江环境通报》2013,33(12):1119-1123
The clinical utility of microarray technologies when used in the context of prenatal diagnosis lies in the technology's ability to detect submicroscopic copy number changes that are associated with clinically significant outcomes. We have carried out a systematic review of the literature to calculate the utility of prenatal microarrays in the presence of a normal conventional karyotype. Amongst 12 362 cases in studies that recruited cases from all prenatal ascertainment groups, 295/12 362 (2.4%) overall were reported to have copy number changes with associated clinical significance (pCNC), 201/3090 (6.5%) when ascertained with an abnormal ultrasound, 50/5108 (1.0%) when ascertained because of increased maternal age and 44/4164 (1.1%) for all other ascertainment groups (e.g. parental anxiety and abnormal serum screening result). When additional prenatal microarray studies are included in which ascertainment was restricted to fetuses with abnormal ultrasound scans, 262/3730 (7.0%) were reported to have pCNCs. © 2013 The Authors. Prenatal Diagnosis published by John Wiley & Sons Ltd. 相似文献
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The fetal fraction (FF) is a function of both biological factors and bioinformatics algorithms used to interpret DNA sequencing results. It is an essential quality control component of noninvasive prenatal testing (NIPT) results. Clinicians need to understand the biological influences on FF to be able to provide optimal post-test counseling and clinical management. There are many different technologies available for the measurement of FF. Clinicians do not need to know the details behind the bioinformatics algorithms of FF measurements, but they do need to appreciate the significant variations between the different sequencing technologies used by different laboratories. There is no universal FF threshold that is applicable across all platforms and there have not been any differences demonstrated in NIPT performance by sequencing platform or method of FF calculation. Importantly, while FF should be routinely measured, there is not yet a consensus as to whether it should be routinely reported to the clinician. The clinician should know what to expect from a standard test report and whether reasons for failed NIPT results are revealed. Emerging solutions to the challenges of samples with low FF should reduce rates of failed NIPT in the future. In the meantime, having a “plan B" prepared for those patients for whom NIPT is unsuccessful is essential in today's clinical practice. 相似文献
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In many agricultural landscapes, roadside (or road verge) environments provide important refuge for threatened native species and ecosystems, and are often selected as benchmark sites to guide restoration activities. However few studies have investigated potential temporal variability in roadside vegetation conditions. In this paper we used archived cadastral maps to determine road age and examine potential variability in roadside vegetation structures in a typical rural landscape in south-eastern Australia. We found significant differences in the density of mature trees for road segments in different road-age categories. The oldest roads (<1870s) were characterized by having the greatest density of large hollow-bearing Eucalyptus trees, but few native conifer trees or shrubs. Roads surveyed when broad-scale clearing commenced (1870–1879), and not the oldest roads, were found to be more intact in terms of the density of large pre-settlement trees, range of tree stem-size classes and overall shrub diversity. By contrast, the youngest roads (post-1900s) had the greatest number of native conifer trees, but few shrubs or large Eucalyptus trees. As a result, roads of different ages had different densities of hollow-bearing trees, which is discussed in terms of past land-use legacies. These results have important implications for selecting roadsides as benchmark sites for restoration activities, and highlight the critical importance of roadsides to conserving native biota in agricultural landscapes. 相似文献
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Rodolfo Salm Lisa Feder Mario Augusto Gonçalves Jardim Nefertiti Hass Euphly Jalles-Filho Ana Maria Costa 《Environment, Development and Sustainability》2009,11(1):161-173
In a meeting between FUNAI (the Brazilian Indian National Foundation) and the Kayapo in the Kayapo village of Aukre, in October
2005, the Kayapo Indians requested support to increase the culture of coconuts (Cocos nucifera) in their lands. The introduction of exotic species is a cause of biological diversity loss throughout the world. However,
this is by no means applicable to all kinds of exotic species. We argue that the culture of coconuts may actually be a useful
tool for the conservation of this country’s indigenous lands, despite criticism to the contrary. It may also be useful as
source for raw material for the indigenous people who are presently experiencing a population boom. For the Kayapo of south-eastern
Amazonia, such a demographic explosion, coupled with their increasing dependence on money to purchase industrialized goods,
tend to substantially increase the pressure on their lands, which still contain a substantial amount of well-preserved seasonally-dry
Amazonian forests. We investigated the actual economic relevance of coconuts for the Kayapo by measuring human and coconut
populations and found that this exotic palm is not important for the subsistence of these Indians, due to coconut scarcity,
and that such importance is not forthcoming. In the Amazon, coconuts may be particularly useful for the Indians’ nutrition
due to the high energetic value of the solid endosperm of the mature fruit. Therefore, given the importance of indigenous
lands for the conservation of the Amazonian forests, the encouragement of subsistence coconut cultures in indigenous lands
is defensible as a measure for the conservation of biodiversity. 相似文献
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Three decades ago, the observation that first trimester fetuses with excess fluid accumulation at the back of the neck were more likely to be aneuploid, gave rise to a new era of prenatal screening. The nuchal translucency (NT) measurement in combination with serum biomarkers and maternal age, resulted in the first trimester combined screening (FTCS) program. The introduction of noninvasive prenatal testing (NIPT) over the past decade has introduced the option for parents to receive highly sensitive and specific screening information for common trisomy from as early as 10 weeks gestation, altering the traditional pathway FTCS pathway. The retention of the 11–13-week NT ultrasound remains important in the detection of structural anomalies; however, the optimal management of pregnancies with a low-risk NIPT result and an isolated increased NT measurement in an era of advanced genomic testing options is a new dilemma for clinicians. For parents, the prolonged period between the initial diagnosis in first trimester, and prognostic information at each successive stage of investigations up to 22–24 weeks, can be emotionally challenging. This article addresses the common questions from parents and clinicians as they navigate the uncertainty of having a fetus diagnosed with an increased NT after a low-risk NIPT result and presents suggested approaches to management. 相似文献