Prenatal diagnosis of Crigler–Najjar syndrome type I by single-strand conformation polymorphism (SSCP)

Crigler–Najjar syndrome type I (CN-I) is a rare and severe inherited disorder of bilirubin metabolism, caused by the total deficiency of bilirubin-UDP-glucuronosyltransferase (UGT) activity. Enzymatic diagnosis cannot be performed in chorionic villi or amniocytes as UGT is not active in these tissues. The cloning of the UGT1 gene and the identification of disease-causing mutations have led to the possibility of performing DNA-based diagnosis. Here we report DNA-based prenatal diagnosis of CN-I in two Tunisian families in whom CN-I patients were diagnosed. As we had previously shown that CN-I was, in Tunisia, associated with homozygosity for the Q357R mutation within the UGT1 gene, we were able to detect this mutation in both families and to show that it was easily recognized by single-strand conformation polymorphism (SSCP) analysis. In both cases, SSCP analysis of fetal DNA showed that the fetus was heterozygous for the Q357R mutation. In one family, the pregnancy was carried to term and a healthy baby was born, whereas, in the other family, the pregnancy is still continuing. Thus the prenatal diagnosis of CN-I is possible, provided disease-causing mutations have been identified. SSCP analysis of DNA prepared either from amniocytes or from chorionic villi is a simple, reliable and fast method for prenatal diagnosis. Copyright © 2002 John Wiley & Sons, Ltd.     

Fetal sexing in possible carriers for duchenne muscular dystrophy

Over a five-year period in the West Midlands there were 34 pregnancies to women who were possible carriers for Duchenne muscular dystrophy and who were known to the Department of Clinical Genetics. Fetal sexing was performed in only ten of 26 pregnancies to women of high or moderate risk, and of the five male fetuses discovered, only two were aborted. Overall, the 34 pregnancies resulted in one miscarriage, 14 males (of whom two were aborted and two were affected) and 19 females. Information was also obtained on five further possible carriers who were ascertained solely because they had an amniocentesis. These five pregnancies led to the birth of one affected male and to the termination of one male fetus.     

GOLD-MINING EFFECTS ON HEAVY METALS IN STREAMS,CIRCLE QUADRANGLE,ALASKA1

Placer gold mining, which extracts gold from buried or exposed alluvia, is often conducted on or near streams. Such mining has the potential to adversely affect water quality. Other heavy metals associated with the gold (such as arsenic, cadmium, lead, zinc, and copper) may be freed to enter streams. Mercury may also enter streams if miners are using it to recover fine particles of gold. These heavy metals are toxic and thus may be harmful to the aquatic life of the streams receiving effluent or runoff from placer mines. In 1982 we sampled two streams intensively - one heavily mined and one unmined - for total recoverable arsenic, mercury, lead, zinc, and copper. Only mercury was not significantly higher in concentration in the mined streams. In 1983 we sampled two stream pairs three times, and 10 other sites at least once, for total and dissolved arsenic, cadmium, mercury, lead, zinc, and copper. Mercury and cadmium were not significantly elevated in mined streams, but the concentrations of total arsenic, lead, zinc, and copper, and dissolved arsenic and zinc were significantly higher in streams below active placer mining sites than in these that were not being mined or those that had never been mined. Additionally, total arsenic, lead, zinc, and copper and dissolved arsenic and copper became elevated after mining began in 1983 on a previously unmined stream.     

Spatial and Temporal Variations in the Sediment Habitat of Ranunculus spp. in Lowland Chalk Streams – Implications for Ecological Status?

Ranunculus spp. are the dominant plants of lowland chalk stream habitats in England. The spatial variability of sediment characteristics (silt–clay, organic matter, total phosphorus and total nitrogen content) within stands of Ranunculus spp. was investigated in 12 rivers in lowland England. Variability was found to be high and there were no discernible differences between samples taken from within Ranunculus and a limited number of samples from bare substrate. For two of these rivers, comparisons were also made between reaches upstream and downstream of waste water treatment works outfalls in terms of the characteristics of the sediments within Ranunculus stands. In one river a clear increase in sediment nutrient, fine and organic material content was observed downstream but in the other there was no consistent difference. Temporal variability was considered for two rivers in the Frome catchment, Dorset, by analysing the monthly variability in sediment organic matter and silt–clay content beneath Ranunculus stands over an annual cycle of growth and die-back. Whilst a clear pattern of fine and organic material retention consistent with seasonal plant growth patterns was evident at one site, the three sites displayed different temporal patterns. This inconsistency is believed to reflect differences in sediment supply at the three sites.     

Economic assessment of dredging operations in Mobile Bay,USA and some additional notes on sustainable management of dredged material

This paper describes a study that was performed to determine the cost-effective method of dredging in Mobile Bay in the United States and to explore the possibility of utilizing the dredged materials in an environmentally sustainable way. An analysis of the historical cost and working time data for hopper dredging and pipeline dredging for Mobile Bay showed that there was not a substantial difference in unit costs between the two methods. However, while the disposal methods for dredged materials were taken into consideration, the pipeline dredging seemed to be a more desirable and environmentally friendly option for dredging in Mobile Bay. In addition to cost analysis, the paper discusses several possible ways of sustainable management of dredged materials. The paper also indicates that if the sediment in Mobile Bay is found to be contaminated by the Deepwater Horizon oil spill, the pipeline dredging will become a more desirable dredging alternative.     

Fate of 17β-estradiol in terrestrial model ecosystems amended with contaminated composted biosolids

Biosolids spread onto agricultural soils are potential sources of steroidal hormones that are able to adversely affect the soil ecosystem. Here we studied the fate of the [4-¹⁴C]-17-β-estradiol hormone in laboratory experiments. First, our results show that only 2.9% of the hormone was mineralized in the soil from a French vineyard. By contrast, the mineralization increased to 7.1% when the hormone was provided in composted biosolids. Second, we found that only a minor part of the estradiol-derived ¹⁴C was mobile and partly transferred to soil leachates. Indeed, the hormone was mainly stabilized in the soil as non-extractable residues. Overall, our findings show that estradiol undergoes two main processes, complete degradation and stabilisation. We therefore conclude that the environmental risk of hormones provided to the soil through composted biosolids is negligible under the conditions of our experiments.     

Bio-Based Polymers and End-of-Life Vehicles

As new materials, such as bio-based plastics and composites, are introduced in vehicles for their improved environmental performance, it is necessary to understand how to efficiently recover these biodegradable materials. This paper provides an overview of the end-of-life phase for automobiles, focusing on the dismantling and shredding processes, and the recovery of materials. Targeted unit operations, such as dismantling of components from vehicles and pretreatment prior to shredding, along with design-for-environment principles, should enable the efficient recovery of materials at the end-of-life phase compared with popularly conceived all-in-one-approaches because of the diverse arrangement of material components.     

The adaptation and control model of user needs: A new direction for housing research

The Canadian context of user needs research in housing is briefly outlined. The Needs and Preferences research model is described and three basic assumptions are outlined. Challenges to the three assumptions are identified, and two empirical studies are invoked to substantiate the critique. An Adaptation and Control Model of user needs research in housing is presented as a possible alternative model that has implications for methodological change and refinement. The opinion is advanced that this model potentially remedies some of the shortcomings of the Needs and Preferences Model.     

Dominance of the odometer over serial landmark learning in honeybee navigation

Honeybees use their visual flow field to measure flight distance. It has been suggested that the experience of serial landmarks encountered on the flight toward a feeding place contributes to distance estimation. Here, we address this question by tracing the flight paths of individual bees with a harmonic radar system. Bees were trained along an array of three landmarks (tents), and the distance between these landmarks was either increased or decreased under two test conditions. We find that absolute distance estimation dominates the search for the feeding place, but serial position effects are also found. In the latter case, bees search only or additionally at locations determined by serial experience of the landmarks.