Molecular prenatal diagnosis: the impact of modern technologies

Originally prenatal diagnosis was confined to the diagnosis of metabolic disorders and depended on assaying enzyme levels in amniotic fluid. With the development of recombinant DNA technology, molecular diagnosis became possible for some genetic conditions late in the 1970s. Here we briefly review the history of molecular prenatal diagnostic testing, using Duchenne muscular dystrophy as an example, and describe how over the last 30 years we have moved from offering testing to a few affected individuals using techniques, such as Southern blotting to identify deletions, to more rapid and accurate PCR-based testing which identifies the precise change in dystrophin for a greater number of families. We discuss the potential for safer, earlier prenatal genetic diagnosis using cell free fetal DNA in maternal blood before concluding by speculating on how more recent techniques, such as next generation sequencing, might further impact on the potential for molecular prenatal testing. Progress is not without its challenges, and as cytogenetics and molecular genetics begin to unite into one, we foresee the main challenge will not be in identifying the genetic change, but rather in interpreting its significance, particularly in the prenatal setting where we frequently have no phenotype on which to base interpretation. Copyright © 2010 John Wiley & Sons, Ltd.     

Adopting and applying eco-design techniques: a practitioners perspective

This paper discusses the findings of a small scale research project which explored the possibility of adopting eco-design techniques. The paper focuses on identifying how eco-design techniques can be determined as being compatible with new product development processes. Via the development of a five stage ‘applicability framework’, this study demonstrates how a compatible suite of tools can be identified for application to product development processes. Testing and validation of this ‘applicability framework’, which was used to identify three key eco-design techniques; namely checklists, guidelines, and a material, energy and toxicity (MET) matrix, is shown to have taken place in relation to the development of a lightweight chemical detector product. It is established that checklists, guidelines and the MET matrix can be used both on a specific product, and also more generally in the design process. In particular, the MET matrix is shown as being used to successfully identify key environmental aspects of the product during its lifetime. The paper concludes by arguing that eco-design techniques may not have been more widely adopted by businesses because such methods are not necessarily generic and immediately applicable, but instead require some form of process-specific customisation prior to use, which can in turn act as a barrier to adoption. It is also highlighted that the shear diversity of pressures that come to bear during the product development process can also act as a barrier to adoption, and that the full integration of eco-design techniques will have to encompass approaches which overcome such pressures.     

Prenatal diagnosis of congenital nephrosis by in utero kidney biopsy

The diagnosis of congenital nephrosis is difficult during the antepartum period. The combination of an elevated amniotic fluid alpha-fetoprotein, a negative acetylcholinesterase, and a negative ultrasound examination is highly indicative of congenital nephrosis; however, these findings can also be associated with a normal gestation. This is the first report of pathologic confirmation of congenital nephrosis from an in utero fetal kidney biopsy. Copyright © 2001 John Wiley & Sons, Ltd.     

Influence of water circulation rate on in situ measurements of benthic community respiration

The relationship between water circulation rate and benthic community respiration was investigated using in situ chambers fitted with variable speed pumps. A strong, positive relationship was exhibited for three estuarine study sites which represented a broad spectrum of sediment characteristics. Both aerobic respiration (65–90% of the total sediment oxygen demand, SOD) and chemical oxygen demand, COD (10–35%) increased with stirring of the overlying waters at velocities up to 20 cm s^-1. Contrary to the notion that COD accounts for any increase in SOD at velocities which initiate sediment resuspension, we observed that aerobic respiration was also stimulated by high velocities. We conclude that measurements of SOD in estuarine environments should be made using water circulation rates which attempt to mimic the natural environment, and that COD cannot be assumed unimportant and should be measured directly.Supported by National Science Foundation Grant SMI 78-03130, Md. Dept. of Natural Resources, MPPSP P2-72-02 (B)Contribution No. 1137, Center for Environmental and Estuarine Studies of the University of Maryland     

Surface water acidification in the South Pennines II. Temporal trends

Data for eight reservoirs in the South Pennines covering the period 1980-98, and for 1988-98 at the River Etherow Acid Waters Monitoring Network site, have been analysed for temporal trends using the Seasonal Kendall test. Rising trends in pH were identified at seven of the eight reservoirs, generally accompanied by declining aluminium levels. Nitrate concentrations have, however, increased sharply at the two reservoirs for which adequate data were available. Data for a wider range of determinands at the Etherow suggest that pH increases in the region can be attributed to declining sulphate concentrations, as a result of reductions in sulphur deposition. Nitrate concentrations have again increased at this site. Results are significant in a national context in that pH recovery, although widely believed to have taken place in the UK since the 1970s, has rarely been shown to have occurred. For the South Pennine region, which has been severely acidified by historically high acid deposition levels, there have clearly been improvements over the last 18 years, although many surface waters remain acidic. Observed trends for nitrate suggest that some of the pH recovery resulting from reduced sulphur deposition may have been offset by nitrogen saturation in the region, due in part to continued high levels of nitrogen deposition.     

Dioxins and furans in emissions from medical waste incinerators

Dioxins and furans were detected in emissions from eight medical waste incinerators tested in California. Total uncontrolled emissions ranged from 363 to 11, 811 nanograms per dry standard cubic meter. The most effective of three wet scrubbers achieved an emissions control efficiency of 95 percent for total PCDD and PCDF. A baghouse was less than 30 percent efficient in removing PCDD and PCDF from the incinerator emissions.     

A comparison of the physical, chemical, and biological properties of sludges from a complete-mix activated sludge reactor and a submerged membrane bioreactor.

The properties of sludges from a pilot-scale submerged membrane bioreactor (SMBR) and two bench-scale complete-mix, activated sludge (CMAS) reactors treating municipal primary effluent were determined. Compared with the CMAS sludges, the SMBR sludge contained a higher amount of soluble microbial products (SMP) and colloidal material attributed to the use of a membrane for solid-liquid separation; a higher amount nocardioform bacteria, resulting from efficient foam trapping; and a lower amount of extracellular polymeric substances (EPS), possibly because there was no selective pressure for the sludge to settle. High aeration rates in both the CMAS and SMBR reactors produced sludges with higher numbers of smaller particles. Normalized capillary suction time values for the SMBR sludge were lower than for the CMAS sludges, possibly because of its lower EPS content.     

The effect of particle size reduction by grinding on subsampling variance for explosives residues in soil

Efforts to characterize the surface soil contamination on military training ranges have been compromised by the inability to obtain representative subsamples of soils submitted to analytical laboratories for determination of explosives residues. Two factors affecting subsampling error for explosives residues were examined using soils collected from hand grenade and anti-tank ranges. These factors were increased subsample size and particle size reduction prior to subsampling of soils. Increasing the subsample size from 2 to 50 g did not reduce the soil subsampling error because of the extreme heterogeneous distribution of the solid contaminants. Alternatively, particle size reduction by machine grinding on a ring mill reduced subsampling error to less than 10% relative standard deviation for replicate analyses using 10-g subsamples.     

Runoff water quality during drought in a zero-order georgia piedmont pasture: nitrogen and total organic carbon

Approximately 11% of the Southern Piedmont (1.8 million ha) is used for pasture and hay production, mostly under low-input management. Few studies have investigated in the region long-term nitrogen and carbon losses in surface runoff, which can be significant. We present 1999 to 2009 hydrologic and water quality data from a rotationally grazed, 7.8-ha, zero-order pasture (W1) near Watkinsville in the Georgia Piedmont. Annual rainfall was 176 to 463 mm below the long-term average (1240 mm) in 7 of the 11 yr. There were 20 runoff events during 86 mo of below-average rainfall (deficit period), compared with 54 events during 46 mo of nondeficit period. Mean event flow-weighted concentration (in mg L) was 0.96 for nitrate-nitrogen (NO-N), 0.97 for ammonium-nitrogen (NH-N), 3.70 for total nitrogen (TN), and 9.12 for total organic carbon (TOC) ( = 43-47; limited due to instrument problem). Nutrient loads (in kg ha per event) averaged 0.04 for NO-N, 0.03 for NH-N, 0.19 for TN, and 0.54 for TOC. Total loads for N and TOC were 6 to 11 times greater from nondeficit than from deficit periods. The observed N concentrations, while well below maximum drinking water standard limits, could pose risk for eutrophication, which can be stimulated at lower concentrations. However, the ability of headwater streams, such as the one downstream of W1, to reduce nutrient concentrations might partially alleviate this concern. The results of this study point to the need to use a long-term dataset that includes measurements made in drought and wet years when evaluating the efficacy of water quality standards.