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81.
We report the preliminary results of a prospective study aimed at evaluating the effectiveness of Down syndrome (DS) screening using second-trimester measurement of maternal serum human chorionic gonadotrophin (hCG) and unconjugated oestriol (uE3) together with maternal age. Reference values for hCG, uE3, and the hCG/uE3 ratio in normal pregnancies were established from more than 3000 normal gestations and found to follow a log-normal statistical distribution. Risk evaluation was made using reference values for affected pregnancies from retrospective studies. Screening of 10 000 women under 38 years resulted in 412 amniocenteses and the prenatal diagosis of six cases of DS, whereas four cases remained undetected until term. In a parallel study, diagnostic amniocentesis was performed in women over 38 years and in women with a previous affected child, and an evaluation of the risk of fetal DS based on serum hCG and uE3 levels was made in all cases. Fourteen cases of DS were detected. Median values for hCG and uE3 in the 24 affected pregnancies were close to the 90th and tenth centiles of the normal reference values, respectively, and thus are in good agreement with the values reported by others in retrospective studies.  相似文献   
82.
In this study, we hypothesised that a reduction in n-3 HUFA availability for higher consumers, as expected with global change, would negatively impact the physiological performances of fish. The aim was to experimentally evaluate the effect of n-3 HUFA dietary content on cardio-respiratory performances of the golden grey mullet (Liza aurata), a microalgae grazer of high ecological importance in European coastal areas. These performances were evaluated in terms of critical swimming speed U crit, associated oxygen consumption MO2, post-exercise oxygen consumption and calcium fluxes in cardiomyocytes. Two replicated groups of fish were fed on a rich (standard diet, SD diet: 1.2 % n-3 HUFA on dry matter basis, DMB) or a poor n-3 HUFA (low n-3 HUFA diet, LD diet: 0.2 % n-3 HUFA on DMB) diet during 5 months and were called SD and LD groups, respectively. The results showed that the LD diet reduced growth rate as well as the aerobic capacity of L. aurata at 20 °C, suggesting that fish may have to save energy by modifying the proportion of energy allocated to energy-demanding activities, such as digestion or feeding. In addition, this LD diet induced higher levels of haematocrit and plasma osmolality, indicating a stress response at the second and third levels in that group. However, the LD diet caused a massive increase in swimming efficiency. This should improve the capacity of L. aurata to migrate and to forage over a wide area. In turn, these could then compensate for the reduction in growth rate and aerobic metabolism.  相似文献   
83.
Illegal, unregulated, and unreported (IUU) fishing poses a major threat to effective management of marine resources, affecting biodiversity and communities dependent on these coastal resources. Spatiotemporal patterns of industrial fisheries in developing countries are often poorly understood, and global efforts to describe spatial patterns of fishing vessel activity are currently based on automatic identification system (AIS) data. However, AIS is often not a legal requirement on fishing vessels, likely resulting in underestimates of the scale and distribution of legal and illegal fishing activity, which could have significant ramifications for targeted enforcement efforts and the management of fisheries resources. To help address this knowledge gap, we analyzed 3 years of vessel monitoring system (VMS) data in partnership with the national fisheries department in the Republic of the Congo to describe the behavior of national and distant-water industrial fleets operating in these waters. We found that the spatial footprint of the industrial fisheries fleet encompassed over one-quarter of the Exclusive Economic Zone. On average, 73% of fishing activity took place on the continental shelf (waters shallower than 200 m). Our findings highlight that VMS is not acting as a deterrent or being effectively used as a proactive management tool. As much as 33% (13% on average) of fishing effort occurred in prohibited areas set aside to protect biodiversity, including artisanal fisheries resources, and the distant-water fleet responsible for as much as 84% of this illegal activity. Given the growth in industrial and distant-water fleets across the region, as well as low levels of management and enforcement, these findings highlight that there is an urgent need for the global community to help strengthen regional and national capacity to analyze national scale data sets if efforts to combat IUU fishing are to be effective.  相似文献   
84.
As part of a project studying the interactions between farming practices, soil erosion processes, and fate of agricultural pollutants into runoff waters, we conducted a pilot study to investigate the relationship between metal contents and metallothionein-2A (MT-2A) as a bioindicator of metal exposure. Runoff water samples were collected between May and November 1999 at the point of outlet of an elementary watershed located in the Paris basin. Selected metals (Al, As, Cd, Cr, Cu, Pb, Hg, Ni, and Zn) were analyzed using conventional techniques. In parallel, human T cells were exposed to water samples for 6 and 18 h and then cell viability and MT-2A gene expression were measured. Results show that among the 10 water samples tested, Al and Zn predominate (highest values = 4.9 and 2.6 microM, respectively), while other metals were below the microM level. Five out of 10 samples induced MT-2A gene expression (30-80% increase at 18 h) as compared with the control. When comparing MT-2A induction profile with metals contents, no obvious correlation was found, suggesting that additional components or parameters are involved. Finally, there was an apparent inverse relationship between Ca concentration and MT-2A gene induction. Although still preliminary, in the absence of longer monitoring, this study shows that MT-2A gene expression is a useful tool to complement chemical analysis in assessing metal elements in water. These combinatory approaches will be pursued and integrated in an ongoing watershed field research project.  相似文献   
85.
The aim of the present study is to assess whether certain ecophysiological responses (contents of total phenols, total proanthocyanidins, and total and simple flavonols), in the needles of Aleppo pines (Pinus halepensis Mill.) may be valid bioindicators for the assessment of the air quality. Samples were taken at five natural sites polluted by various pollutants (NO, NO2, other NOx, SO2, and O3). The results show a decrease in total phenol concentrations with levels of nitrogen oxide pollutions (significant negative correlations between the total phenol concentrations and concentrations of NO, NO2, and other NOx). Total flavonoids (total flavonols and proanthocyanidins) are useful bioindicators for ozone pollution (significant negative correlations between total proanthocyanidins and the concentrations of ozone and significant positive correlations between total flavonols and the ozone pollution). Sulfur dioxide pollution is distinguished by low concentrations in quercetin, isorhamnetin, and kaempferol (significant negative correlations between these simple flavonols and the concentrations of SO2). This work confirms the strong interest of using the phenolic compounds of Pinus halepensis as biological indicators of air quality.  相似文献   
86.
87.
The fate of the benthic bacterial biomass is a topic of major importance in understanding how soft-bottom environments function. Because of their high abundance, production and nutritional value, benthic bacteria may constitute an important food resource for benthic fauna. The trophic role of bacteria for a nematode community on the Brouage mudflat (Marennes-Oléron-France), dominated by three species: Chromadora macrolaima (64% of the abundance), Daptonema oxycerca (15%) and Ptycholaimellus jacobi (8%), was determined in grazing experiments using 15N pre-enriched bacteria. On intertidal flats, seasonal, tidal and circadian cycles induce strong variations in environmental conditions. Grazing experiments were performed in order to measure the effects of abiotic (temperature, salinity and luminosity) and biotic (bacterial and algal abundances) factors on assimilation rates of bacteria by nematodes. In order to assess simultaneously bacteria and algal assimilation rates, algal abundances were modified adding 13C pre-enriched Navicula phyllepta. Assimilation rate was significantly lower at 5°C; moreover, general trend shows a prominent temperature effect with an optimum around 30°C. Assimilation at salinity 18 was not significantly different from the assimilation at salinity 31. Assimilation was higher under light conditions than in the dark. Above 109 bacteria ml−1, assimilation of bacteria remained unaffected by bacterial abundance. However, assimilation of algae increased with the algal concentration. Nematode kept feeding under conditions of stress, which are typical of the surficial sediment habitat and they appeared to be principally dependent on the algal resource.  相似文献   
88.
Regional Environmental Change - Climate change and a growing population around the Mediterranean Rim are increasing the need for water and, consequently, the pressure on resources in terms of both...  相似文献   
89.
Blood clinical-chemical parameters (BCCPs) are used to investigate physiological consequences attributed to exposure to anthropogenic stressors, such as exposure to Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and Dechlorane Plus (DP), which are flame retardants (FRs), on avian health. Japanese quail (Coturnix japonica) were used as a model species to investigate individual and mixture effects of both FRs by injecting different concentrations (5, 50, or 500 ng/µL) of either of these compounds as well as a 1:1 mixture of both into fertilized eggs. To estimate post-hatching effects, 18 BCCPs were evaluated from 101 chicks at day 14. Albumin levels were found to be significantly elevated in the groups exposed to high doses of TDCIPP alone as well as a mixture of TDCIPP and DP. However, during the course of the study, the initial corn-based feed had to be substituted by a fishmeal-based feed. The 8 days consuming the new feed played a significant role on 12 of 18 BCCPs measured. Consequently, it is recommended that dietary habits need to be considered when investigating the physiological impact of contaminants using BCCPs as biomarkers in growing nestlings both in controlled in vivo and field experiments.  相似文献   
90.
In estuaries, eelgrass meadows contribute to fundamental ecosystem functions of estuaries, providing food to several predators and buffering the negative effects of eutrophication. We asked whether the presence of the eelgrass Zostera noltii decreased the nitrogen concentration in the overlying water, affected the sources of nitrogen sequestrated by primary producers and changed the benthic and pelagic food web structures. We also studied the importance of these food webs in providing food to fish. We compared bare sediment to sediment covered by a Z. noltii meadow, and examined nutrient concentrations in the water column and δ15N in primary producers as indicators of anthropogenic inputs of nutrients. We then measured both δ13C and δ15N in the tissues of plants and consumers to establish food web structures. There were no differences in the concentrations and sources of nitrogen between sites. Rather, δ15N values indicated anthropogenic inputs of N (e.g. sewage discharges, agriculture) in both sites. There were no major differences in the structure of the planktonic food web, which was in part sustained by particulate organic matter and supported most predator fish, and in the structure of the benthic food web. Nonetheless, there were differences in the sources of food for omnivore consumers and for the detritivore Scrobicularia plana. Overall, the benthic food web did not use food derived from the eelgrass or macroalgae deposited on the substratum. Suspension feeders used particulate and sediment organic matter, whereas the δ13C and δ15N values of the other consumers indicated a likely contribution of benthic microalgae. Furthermore, in both habitats we found large variability in the isotope signatures of benthic macrofauna consumers, which did not allow distinguishing clearly different trophic groups and indicated a high level of omnivory and a mixed diet opportunistically making use of the availability of food in the surroundings.  相似文献   
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