Pseudomosaicism for trisomy 13: Three case reports

Pseudomosaicism is of particular concern in prenatal diagnosis when it involves mosaicism for a cytogenetic abnormality associated with a clinical syndrome which is compatible with postnatal life, such as trisomies for chromosomes 13, 18, and 21. The lack of data regarding the outcome of pregnancies involving these specific kinds of pseudomosaicism makes genetic counselling difficult. Three cases of prenatal diagnosis of pseudomosaicism for trisomy 13, each of which had a normal outcome, will be presented (Tables 1 and 2). The three main areas for consideration are: (1) the genetic counselling issues, (2) the additional prenatal diagnostic options available to evaluate the status of the fetus in an attempt to identify some of the clinical features of trisomy 13, and (3) the outcome of the pregnancies.     

Relevance of enantiomeric separations in environmental science

A significant number of all organic chemicals that are released into the environment are racemic mixtures. Most environmental regulations and scientific environmental studies treat racemic mixtures as though they were single, pure compounds. This can lead to incorrect toxicological, distribution, degradation and other data. A series of new enantioselective chromatographic techniques have been developed that allow the facile separation and quantitation of chiral compounds of environmental importance. Nineteen racemic compounds that have been or currently are being released to the environment are resolved. These include: rodenticides--Warfarin, Coumachlor and Coumafuryl; insecticides--Crufomate, Bulan, Fonofos, Mitotane; insect repellent--Ethohexadiol; herbicides and fungicides--Ancymidol, Silvex, Napropamide, phenyl mercuric lactate, 2-[3-chlorophenoxy]propionamide, and 2-chloropropionic acid; and halocarbons-1,2-dichloropropane, 2-bromo-1-chloropropane, 1,2-dibromo-3-chloropropane, 2,3-dichlorobutane and alpha-1,2,3,4,5,6-hexachlorocyclohexane. Several examples are given to illustrate the importance of enantioselective measurements of these and other compounds. Choosing the proper chromatographic technique and chiral stationary phase based on analyte structure is also discussed.     

An Experiment in Making Water Affordable: Philadelphia’s Tiered Assistance Program (TAP)

The ability to pay for water and wastewater services is a growing issue in the developed world. To this point in time, utilities have helped customers grappling with affordability issues using different types of customer assistance programs (CAPs). Income‐based billing approaches differ from CAPs in that bills are structured so as to be affordable for customers at the outset. Recently, the City of Philadelphia implemented an innovative program to work towards resolving the affordability problem in their city using income‐based billing. This tiered assistance program or TAP structures bills for water, wastewater, and stormwater services to program enrollees’ income. Given the innovative nature of the program, this paper describes the rollout of TAP and assesses the impact of the program on customers and utility revenues. The paper closes with a critical assessment of TAP and considerations for utilities evaluating the implementation of similar programs.     

A spatiotemporal Richards–Schnute growth model and its estimation when data are collected through length-stratified sampling

Environmental and Ecological Statistics - We propose a spatiotemporal generalized von Bertalanffy (vonB) growth model that also includes between-individual (BI) variation and male/female...     

The Need for Flexibility in Conservation Practices: Exotic Species as an Example

To garner support for biodiversity from the World’s human population, conservation biologists need an open-minded, integrated conservation strategy. We suggest that this strategy should include efforts to (1) preserve existing high quality, diverse ecosystems, (2) remediate impaired systems, (3) balance the needs of people and ecological resources, and (4) engender appreciation of nature and its services. We refer to these four key tenets as reservation, restoration, reconciliation, and reconnection. We illustrate these concepts by presenting the debate surrounding the management of exotic species from an unusual perspective, the benefits of exotic species. By this example we hope to encourage an integrated approach to conservation in which management strategies can be flexible, adjusting to society’s needs and the overall goals of conservation.     

Evaluation of lot-to-lot repeatability and effect of assay media choice in the recombinant Factor C assay

Measurement of environmental endotoxin exposures is complicated by variability encountered using current biological assay methods arising in part from lot-to-lot variability of the Limulus-amebocyte lysate (LAL) reagents. Therefore, we investigated the lot-to-lot repeatability of commercially available recombinant Factor C (rFC) kits as an alternative to LAL. Specifically, we compared endotoxin estimates obtained from rFC assay of twenty indoor dust samples, using four different extraction and assay media, to endotoxin estimates previously obtained by Limulus amebocyte lysate (LAL) assay and amounts of 3-hydroxy fatty acids (3-OHFA) in lipopolysaccharide (LPS) using gas-chromatography mass spectroscopy (GC-MS). We found that lot-to-lot variability of the rFC assay kits does not significantly alter endotoxin estimates in house dust samples when performed using three of the four assay media tested and that choice of assay media significantly altered endotoxin estimates obtained by rFC assay of house dust samples. Our findings demonstrate lot-to-lot reproducibility of rFC assay of environmental samples and suggest that use of rFC assay performed with Tris buffer or water as the extraction and assay medium for measurement of endotoxin in dust samples may be a suitable choice for developing a standardized methodology.     

Controversies in antenatal corticosteroid treatment

Antenatal corticosteroids are now established as one of the cornerstones of therapy in the prevention of neonatal morbidity and mortality prior to preterm birth. Although this practice is widely accepted, a significant number of controversies exist. This review explores the knowledge gaps regarding the use of antenatal corticosteroids in the preterm, late preterm and term populations. Furthermore, the role of antenatal corticosteroids in special populations, such as diabetes, multiple pregnancies and periviable gestations, where high-quality data from randomized controlled trials are lacking, is also considered.