Isolating fetal nucleated red blood cells from maternal blood: The baylor experience—1995

In our previous work we have isolated fetal cells from maternal blood and used fluorescent in situ hybridization (FISH) for chromosome-specific probes to detect aneuploidy. Current efforts in the Baylor College of Medicine programme are focusing on obtaining consistency in flow-sorting methodology and on determining sensitivity and specificity. To this end, systematic evaluation of five glycophorin A (gly A) antibodies all produced agglutination, leading us to abandon the use of gly A antibodies for positive selection of fetal cells. Conversely, we have found LDS-751 to be useful for nuclear selection. CD45 negative selection can best be accomplished by the use of flasks coated with goat antibodies against mouse antibodies. Positive selection by flow sorting for either CD71⁺ cells or gamma-globin-positive cells seems to be successful. Using these two approaches, we have recently detected male (fetal) cells in pregnancies in which the fetus was 46, XY in 10 of 18 and in 12 of 14 cases, respectively.     

Self-insurance against natural disasters

Expenditures on self-insurance to mitigate the effects of natural disasters on the value of private assets are examined in a model where individuals are partially insured against financial loss by a public relief program and where private insurance is unavailable. The model predicts that optimal private expenditures on self-insurance will be excessive or insufficient according to the nature of the technology by which individuals protect their assets. The comparative static effects of variations in the level of public compensation, individual wealth, and attitudes toward risk and the degree of environmental uncertainty on self-insurance expenditures and on the magnitude and frequency of public compensation are also characterized and their implications for remedial government policies are examined.     

Linking on-farm dairy management practices to storm-flow fecal coliform loading for California coastal watersheds

How and where to improve water quality within an agricultural watershed requires data at a spatial scale that corresponds with individual management decision units on an agricultural operation. This is particularly true in the context of water quality regulations, such as Total Maximum Daily Loads (TMDLs), that identify agriculture as one source of non-point source pollution through larger tributary watershed scale and above and below water quality investigations. We have conducted a systems approach study of 10 coastal dairies and ranches to document fecal coliform concentration and loading to surface waters at the management decision unit scale. Water quality samples were collected on a storm event basis from loading units that included: manure management systems; gutters; storm drains; pastures; and corrals and lots. In addition, in-stream samples were collected above and below the dairy facilities and from a control watershed, managed for light grazing and without a dairy facility or human residence and corresponding septic system. Samples were analyzed for fecal coliform concentration by membrane filtration. Instantaneous discharge was measured for each collected sample. Storm runoff was also calculated using the curve number method (SCS, 1985). Results for a representative dairy as well as the entire 10 dairy data set are presented. Fecal coliform concentrations demonstrate high variability both within and between loading units. Fecal coliform concentrations for pastures range from 206 to 2,288,888 cfu/100 ml and for lots from 1,933 to 166,105,000 cfu/100 ml. Mean concentrations for pastures and lots are 121,298 (SE=62,222) and 3,155,584 (SE=1,902,713) cfu/100 ml, respectively. Fecal coliform load from units of concentrated animals and manure are significantly more than units such as pastures while storm flow amounts were significantly less. Compared with results from earlier tributary scale studies in the watershed, this systems approach has generatedwater quality data that is beneficial for management decisions because of its scale and representation of current management activities. These results are facilitating on-farm changes through the cooperative efforts of dairy managers, regulatory agency staff, and sources of technical and financial assistance.     

Mobility of aniline, benzoic acid, and toluene in four soils and correlation with soil properties

Soil properties and retention mechanisms affecting the relative mobility of aniline, benzoic acid, and toluene in Cecil sandy loam (clayey, kaolinitic, thermic Typic Hapludults), Holdredge silt loam (fine-silty, mixed, mesic Typic Argiustolls), Sharpsburg silty clay loam (fine, montmorillonitic, mesic Typic Argiudolls), and Valentine fine sand (mixed, mesic Typic Ustipsamments) were delineated in laboratory studies. The effect of the synthetic organic compounds (SOCs) was also determined on effective organic campounds (SOCs) was also determined on effective cation exchange capacity (ECEC) of the soils. Benzoic acid was most mobile of the SOCs but was retained in the Cecil soil by hydrogen bonds to Fe oxides. Toluene was least mobile and probably was hydrophobically sorbed to all soils. Aniline was electrostatically retained in protonated form to organic and inorganic exchange sites of the soils and reduced the ECEC of aniline-treated Holdredge and Sharpsburg soils.     

Biodegradation of benzene, toluene, ethylbenzene and xylenes in gas-condensate-contaminated ground-water

The rate and extent of biodegradation of benzene, toluene, ethylbenzene and xylenes (BTEX) in ground-water was studied in samples from a contaminated site which contained total BTEX concentrations of up to 20 000 microg litre(-1). All compounds were rapidly degraded under natural aerobic conditions. Elevation of incubation temperature, supply of organic nutrients or addition of inorganic fertiliser did not increase the rate or extent of biodegradation and it appeared that oxygen supply was the factor limiting BTEX degradation at this site. Attempts to increase the dissolved oxygen concentration in the ground-water by the addition of hydrogen peroxide to give a final concentration of 200 mg litre(-1) resulted in the complete inhibition of biodegradation. No biodegradation occurred under anaerobic conditions except when nitrate was provided as a terminal electron acceptor for microbial respiration. Under denitrifying conditions there was apparent biodegradation of benzene, toluene, ethyl-benzene, m-xylene and p-xylene but o-xylene was not degraded. Degradation under denitrifying conditions occurred at a much slower rate than under oxygenated conditions.     

Mercury levels in eggs, tissues, and feathers of herring gulls Larus argentatus from the German Wadden Sea Coast

The relationships between mercury levels in eggs, tissues, and feathers of male and female herring gulls caught at their nests at a colony on the German Wadden Sea Coast were investigated, and an assessment of mercury intake and excretion of these birds was made. Samples of the liver, ovary, pectoral muscle, and body feathers, as well as the primary feather (in some cases), and eggs were taken from 37 adult herring gulls. Analysis of total mercury in all samples showed that body-feather and tissue levels were independent of sex. There was, however, a significant difference between levels of mercury in the primary feathers of male and female birds. Egg levels were not correlated to pectoral muscle, ovary, or feather levels although they were positively correlated with mercury levels in the liver. Liver levels were in turn correlated with mercury levels in the ovary. The ratio of mean feather to mean egg concentration ranged from 3.7 to 5.5 according to which feather was used. It was estimated that herring gulls from the Wadden coast ingested between 825 and 1337 microg of mercury in the year prior to analysis. It was also estimated that female birds may excrete over 20% more mercury via their eggs than could be excreted by male birds.     

The vulnerability of small island States to sea level rise: the need for holistic strategies

There is uncertainty about climate change and its socioenvironmental implications, but the vulnerability of small island states to hazardous events is likely to become increasingly significant. It will not be a normally benign sea that rises but the incidence of storms and cyclones can be assumed to increase with tropical sea-surface temperatures. The proportional socioeconomic impact of tropical cyclone disasters makes these of crucial significance to small islands and small island states. Sea-defences are of little use (and may not be feasible at all) against the damage caused by tropical cyclones and some sea-surges. Social and economic adjustments are also required to parallel erosion control; and disaster preparedness "longstops" must be further developed as a matter of urgency. Apparently small measures must not be displaced by images of ultimate, massive catastrophe; adjustments may serve other functions in society as well. International and bilateral measures are required to take account of migration and"ecological refugees" and national administrations may require modification to take appropriate account of this most crucial of environmental phenomena.     

Floodplain management in London,Ontario, Canada: Assessing implementation of section 28 of the conservation authorities act

An assessment of floodplain regulation by the Upper Thames River Conservation Authority in the City of London for the period 1978–1989 was undertaken. Utilizing a mix of data sources available through the conservation authority office, questionnaires administered to flooplain residents, interviews with relevant government officials, and housing statistics, the study concludes that regulations have been administered in an equitable and efficient manner. However, regulations have had some problems in controlling all development activity and in addressing policy objectives. Problems arise from weaknesses in the Conservation Authorities Act, an ensuing lack of judicial and participating municipal support in prosecuting violations, and inadequate monitoring and enforcement of development activity. Without addressing these issues, the basic problems associated with floodplain management in Ontario will remain.