Prenatal diagnosis,prediction of outcome and in utero therapy of isolated congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) can be associated with genetic or structural anomalies with poor prognosis. In isolated cases, survival is dependent on the degree of lung hypoplasia and liver position. Cases should be referred in utero to tertiary care centers familiar with this condition both for prediction of outcome as well as timed delivery. The best validated prognostic indicator is the lung area to head circumference ratio. Ultrasound is used to measure the lung area of the index case, which is then expressed as a proportion of what is expected normally (observed/expected LHR). When O/E LHR is < 25% survival chances are < 15%. Prenatal intervention, aiming to stimulate lung growth, can be achieved by temporary fetal endoscopic tracheal occlusion (FETO). A balloon is percutaneously inserted into the trachea at 26–28 weeks, and reversal of occlusion is planned at 34 weeks. Growing experience has demonstrated the feasibility and safety of the technique with a survival rate of about 50%. The lung response to, and outcome after FETO, is dependent on pre-existing lung size as well gestational age at birth. Early data show that FETO does not increase morbidity in survivors, when compared to historical controls. Several trials are currently under design. Copyright © 2008 John Wiley & Sons, Ltd.     

Successful Treatment of Low PAH-Contaminated Sewage Sludge in Aerobic Bioreactors (7 pp) *

Background, Aims and Scope Polycyclic Aromatic Hydrocarbons (PAHs) are known for their adverse and cumulative effects at low concentration. In particular, the PAHs accumulate in sewage sludge during wastewater treatment, and may thereafter contaminate agricultural soils by spreading sludge on land. Therefore, sludge treatment processes constitute the unique opportunity of PAH removal before their release in the environment. In this study, the ability of aerobic microorganisms to degrade light and heavy PAHs was investigated in continuous bioreactors treating trace-level PAH-contaminated sludge. Methods Several aerobic reactors were operated under continuous and perfectly mixed conditions to simulate actual aerobic sludge digesters. Three sterile control reactors were performed at 35°C, 45°C or 55°C to assess PAH abiotic losses under mesophilic and thermophilic conditions. Three biological reactors were also operated at 35°C, 45°C or 55°C. Furthermore, 250 mM methanol were added in an additional mesophilic reactor (35°C). All reactors were fed with long-term PAH-contaminated sewage sludge, and PAH removal was assessed by inlet/outlet mass balance. In this study, PAH compounds ranged from 2 to 5-unsubstituted aromatic rings, i.e. respectively from Fluorene to Indeno(123cd)pyrene. Results and Discussion Significant abiotic losses were observed for the lightest PAHs (fluorene, phenanthrene and anthracene), while biodegradation occurred for all PAHs. More than 80% of the lightest PAHs were removed. Biodegradation rates inversely correlated with the increasing molecular weight, and seemed limited by the low bioavailability of the heaviest PAHs (only 50% of removal). The enhancement of PAH bioavailability by increasing the process temperature or adding methanol was tested. A temperature increase from 35°C to 45°C and then to 55°C significantly enhanced the biodegradation of the heaviest PAHs from 50% to 80%. However, high abiotic losses were observed for all PAHs at 55°C, which was attributed to volatilization. Optimal conditions were found at 45°C considering the low abiotic losses and the high PAH biodegradation rates. Similar performances were achieved by addition of methanol in the sludge. It was concluded that increasing temperatures or addition of methanol favored PAH diffusion from solids to an aqueous compartment, and enhanced their bioavailability to PAH-degrading microorganisms. Conclusion In this study, the use of long-term acclimated aerobic ecosystems showed the high potential of aerobic microorganisms to degrade a wide range of PAHs at trace levels. However, PAH biodegradation was likely controlled by their low bioavailability. Two aerobic processes have been finally proposed to achieve efficient decontamination of sewage sludge, at 45°C or in the presence of methanol. The PAH concentrations in reactor outlet were lower than the French requirements, and allow the treated sludge to be spread on agricultural land. Recommendations and Outlook The two proposed aerobic processes used physical or chemical diffusing agents. The global ecological impact of using the latter agents for treating trace level contamination must be considered. Since methanol was completely removed during the process, no additional harm is expected after treatment. However, an increase of temperature to 45°C could drastically increase the energy demand in full-scale plants, and therefore the ecological impact of the process. Moreover, since bioavailability controls PAH biodegradation, efficiency of the processes could also be influenced by the hydraulic parameters, such as mixing and aeration rates. Further experimentations in a pilot scale are therefore recommended, as well as a final assessment of the global environmental benefit of using such aerobic processes in the bioremediation of trace level compounds. - Abbreviations (PAHs): Ant – anthracene; B(a)A – benzo(a)anthracene ; B(b)F – benzo(b)fluoranthene; B(k)F – benzo(k)fluoranthene; B(ghi)P – benzo(g,h,i)perylene; B(a)P – benzo(a)pyrene; Chrys – chrysene; DB – dibenzo(a,h)anthracene; Fluor – fluoranthene; Fluo - fluorene; Ind – indeno(1,2,3-c,d)pyrene; Phe - phenanthrene; Pyr – pyrene - * The basis of this peer-reviewed paper is a presentation at the 9th FECS Conference on 'Chemistry and Environment', 29 August to 1 September 2004, Bordeaux, France.     

Biological Air Quality Monitoring: a Review

Air quality monitoring is currently ensured by captors measuring few physicochemical parameters, then they cannot evaluate unforeseen compounds and the interaction effects of pollutants. On the contrary, the use of bioindicators can answer these problems. Among them, plants are used in two ways:1) Passive bioindicators: trees, lichens and mosses are used to determine the distribution and even the contaminants long-term effects on vast zones and, possibly, the concentrations of pollutants to which they were exposed.2) Active bioindicators: tobacco and mosses make available the defective zones in plants and enable determination of deposition fluxes.Moreover, techniques based on biomarkers identification should increase the answer's sensitivity. However, the plants present the disadvantage of being unable to provide a response in a time lapse comparable with that of the on-line analysers. Lastly, the development of tools using animal cells should allow, in the near future, to measure the total polluting load under conditions close to those of the routine techniques. Then, the real impact of the contaminant on public health could be approached.     

Targeted sampling protocol as prelude to bacterial source tracking with Enterococcus faecalis

Recent studies suggest that host origin databases for bacterial source tracking (BST) must contain a large number of isolates because bacterial subspecies change with geography and time. A new targeted sampling protocol was developed as a prelude to BST to minimize these changes. The research was conducted on the Sapelo River, a tidal river on the Georgia coast. A general sampling of the river showed fecal enterococcal numbers ranging from <10 (below the limit of detection) to 990 colony-forming units (CFU) per 100 mL. Locations with high enterococcal numbers were combined with local knowledge to determine targeted sampling sites. Fecal enterococcal numbers around one site ranged from <10 to 24,000 CFU per 100 mL. Bacterial source tracking was conducted to determine if a wastewater treatment facility at the site was responsible for this contamination. The fecal indicator bacterium was Enterococcus faecalis. Ribotyping, automated with a RiboPrinter (DuPont Qualicon, Wilmington, DE), was the BST method. Thirty-seven ribotypes were observed among 83 Ent. faecalis isolates obtained from the Sapelo River and the wastewater lagoon. Sixteen ribotypes were associated with either the river or the lagoon, and only five ribotypes (14%) were shared. Nevertheless, these five ribotypes represented 39 of the 83 Ent. faecalis isolates, almost a majority (47%). These results suggest that the fecal contamination in the river came from the wastewater treatment facility. As a prelude to BST, targeted sampling minimized subspecies changes with geography and time, and eliminated the need for a permanent host origin database by restricting BST to a small geographic area and requiring sampling to be completed in one day.     

Courting virtual rivals increase ejaculate size in sticklebacks (<Emphasis Type="Italic">Gasterosteus aculeatus</Emphasis>)

Sperm competition occurs when sperm of two or more males compete to fertilize a given set of eggs. Game-theory models of sperm competition predict that males, which face an increased risk of sperm competition, will invest more sperm in a mating. In the pair-spawning three-spined stickleback ( Gasterosteus aculeatus), males attempt to steal fertilizations (i.e. to sneak) when they are in the courting phase, but not when they are parental. The behaviour of neighbouring males may therefore indicate the risk of sperm competition. We visually confronted males before spawning with computer animations of the same virtual stickleback showing two different behaviours: either courting (high risk of sperm competition) or brood-caring (low risk of sperm competition). We show that males invest significantly more sperm (absolutely and relatively with respect to available sperm in the testes) after the courting stimulus. The relative investment ratio between the courting and the brood-caring treatment was on average 1.75. Three-spined sticklebacks thus seem to assess the risk of sperm competition by the behaviour of neighbours and to adjust their ejaculate accordingly. This result suggests that the evolutionary force of sperm competition has led to precise mechanisms of future risk assessment.