Molecular response of a sub-antarctic population of the blue mussel (Mytilus edulis platensis) to a moderate thermal stress.

The Kerguelen Islands (49°26'S, 69°50'E) represent a unique environment due to their geographical isolation, which protects them from anthropogenic pollution. The ability of the endemic mussel, part of the Mytilus complex, to cope with moderate heat stress was explored using omic tools. Transcripts involved in six major metabolic functions were selected and the qRT-PCR data indicated mainly changes in aerobic and anaerobic energy metabolism and stress response. Proteomic comparisons revealed a typical stress response pattern with cytoskeleton modifications and elements suggesting increased energy metabolism. Results also suggest conservation of protein homeostasis by the long-lasting presence of HSP while a general decrease in transcription is observed. The overall findings are consistent with an adaptive response to moderate stresses in mussels in good physiological condition, i.e. living in a low-impact site, and with the literature concerning this model species. Therefore, local blue mussels could be advantageously integrated into biomonitoring strategies, especially in the context of Global Change.

Effects of laryngoscope handle light source on the light intensity from disposable laryngoscope blades.

A bench-top study was performed to assess the effects of different laryngoscope handles on the light intensity delivered from disposable metal or plastic laryngoscope blades. The light intensity from both the handle light sources themselves and the combined handle and laryngoscope blade sets was measured using a custom-designed testing system and light meter. Five samples of each disposable blade type were tested and compared with a standard re-usable stainless steel blade using three different handle/light sources (Vital Signs LED, Heine 2.5 V Xenon and 3.5 V Xenon). The light intensity delivered by the disposable blades ranged from 790 to 3846 lux for the different handle types. Overall, the 3.5 V Heine handle delivered the highest light output (p < 0.007) in comparison with the other handles. For the disposable blades, the overall light output was significantly higher from the plastic than the metal blades (p < 0.001).

Effects of agricultural pesticides on the health of Rana pipiens frogs sampled from the field.

There is evidence that over the last 30 years, there have been mass declines in diverse geographic locations among amphibian populations due to disease outbreaks. Multiple causes have been suggested to explain this increase in disease incidence. Among these, climate changes, environmental pollution and reduced water quality are gaining attention. Indeed, some chemicals of environmental concerns are known to alter the immune system. It is possible that exposure to these pollutants could alter the immune system of anurans and render them more susceptible to different pathogens. In this study, we sampled Rana pipiens in five different sites near St. Lawrence River (Quebec, Canada) during the months of July and September in 2001. Two of these sites were protected areas, in which low levels of pesticides were detected, while the remaining three sites were located in areas with intensive corn and soybeans cultivations. Our results demonstrated that frogs living in agricultural regions are smaller in size and weight than frogs living in areas with lower levels of pesticides at both sampling times. Moreover, we have observed a significant decrease in the number of splenocytes (cellularity) and the phagocytic activity in frogs sampled in impacted sites. Taken together, these results suggest that frogs living in agricultural regions might be more vulnerable to infections and diseases through their smaller size and alteration of their immune system. Our results also contribute to the overall discussion on factors involved in amphibian declines.

The effect of sterilisation on the light intensity of the reusable Trachlight™.

We examined the light intensity delivered by the Trachlight™ reusable lightwand and the effect of repeated sterilisation on this light intensity. Using a light meter and test chamber, the light intensity of 12 new Trachlights and 31 Trachlights available in operating theatres was measured. In addition, five new devices underwent 30 repeated sterilisations with light intensity measurement after each cleaning. There was no difference between the light intensity of new Trachlights (median (IQR [range]) 2282 (2202-2780 [1970-4400])) lux and the devices currently in service (2295 (2018-2796 [1649-3280]) lux (p = 0.27)). The median (range) number of uses for devices currently in service was only 3 (0-9). There was, however, significant light intensity loss after 10, 20 and 30 cleanings (p = 0.001). After 10 cleanings, the mean light intensity was 75% of initial output, and after 30 cycles, light intensity was 59% of initial output.

Short-term physiological effects of a xenobiotic mixture on the freshwater mussel Elliptio complanata exposed to municipal effluents.

The aim of this study was to investigate the short-term effects of tertiary-treated municipal effluents on the freshwater mussel Elliptio complanata. Caged mussels were immersed during 2 weeks in a river located North of Montreal Island, upstream/downstream the outfall and in one reference site located at the beginning of the Rivière des Prairies. A selection of biomarkers was analyzed to depict changes on various physiological systems: general physiology (mussel viability, condition index and gonado-somatic index), immune status (hemocyte viability, cellularity, phagocytosis efficiency, NK-like cytotoxic activity and lysozyme activity), inflammation (cyclo-oxygenase activity), detoxification (glutathione-S-transferases activity) and vitellogenesis (alkali-labile phosphate level). The analysis of total and fecal coliform counts in water and of heterotrophic bacteria levels in mussel tissues showed that the bacteriological quality of the water strongly decreased from the reference site to the downstream site. This was correlated with a significant loss of weight and an increase of mussel mortality. Cellularity and phagocytosis efficiency were significantly increased in the downstream site compared to the reference site. Though not statistically significant, lysozyme activity was also increased. NK-like cytotoxicity, activity of the pro-inflammatory enzyme COX and the levels of ALP and MT were not significantly changed. Conversely, the municipal effluents induced a significant increase of GST activity in downstream site, indicating a stimulation of detoxification metabolism. Altogether, these results confirm that a short-term exposure to a mixture of bacterial and chemical compounds released by the wastewater treatment plant La Pinière induces adverse physiological effects in E. complanata, as observed with the modulation of immune response and induction of detoxification metabolism.

Forensic and police identification of "X" bodies. A 6-years French experience.

The identification of X bodies is an everyday preoccupation in forensic pathology. This retrospective analysis studied all methods of identification and characteristics of unidentified bodies arrived in the Department of Forensic Medicine and Pathology (University Hospital R. Poincaré, Garches, France) during a 6-years period (2003-2009). The aim was to determine the identification methods used during all the forensic investigations, but also to study causes and manner of death in this sample of the population. A total of 9.1% of all autopsies were on X cadavers (217 cases out of 2384). On this total, only 134 of them have been included in our series after exclusion of archaeological and animal samples, but also of unidentified individuals or incomplete data available. Almost 28% of them have been identified with molecular biology (DNA), 23% with odontological examination, 7.5% with fingerprinting and 6.7% with autopsy data. Manner of death was mainly suicide (40.3%) especially by asphyxia following drowning, then accidental death (17.9%) especially consecutive to multiple trauma after traffic accident, acute carbon monoxide intoxication or carbonization in a fire. A total of 11.9% natural deaths were found (50% of them being of cardio-vascular origin) and 11.2% of homicides (with the use of firearm in a third of them). For 18.7% of X cadavers, the mode of death was undetermined. 46.4% of all unidentified bodies in our series were only identified by the police investigations, using physical recognition (direct or with photographs) or personal effects or identity documents in close relationship with the body. Our study highlights the fact that quite half of all unidentified bodies are inhumed with an identity not scientifically proved. Bodies which remained unidentified after all investigations represent 10.2% of X cadavers (if we consider a group of 176 cases composed of our study sample of 134 cases plus 24 subjects identified just before the autopsy and the 18 cases which remained unidentified) and 0.8% of all autopsies performed in the department.

Immunotoxicological effects of an activated-sludge-treated effluent on rainbow trout (Oncorhynchus mykiss).

Municipal effluents are often treated by biological processes designed to enhance natural biodegradation that introduce important changes to the local bacterial community and contaminant status. The purpose of this study was to examine the immunotoxicological effects of an activated sludge treated urban effluent on rainbow trout (Oncorhynchus mykiss). Trout specimens were exposed to increasing concentrations of the effluent at 0.1%, 1% and 10% v/v dilutions for 30 days at 15 degrees C. After the exposure period, the leukocytes were isolated from the anterior kidney and the following parameters were determined: phagocytic activity, lymphoblastic transformation and natural cytotoxic activity. The results revealed that phagocytic activity was not significantly affected by the biologically treated effluent. Natural cytotoxic activity was significantly increased at an effluent threshold concentration of 3% v/v at an effector/target cell ratio of 20:1 and 40:1. Stimulated lymphocyte T and B proliferation was significantly decreased at a threshold concentration of 0.3%. However, neither the unstimulated lymphocyte T nor lymphocyte B proliferation was significantly affected by effluent exposure. The results suggest that the activated-sludge-treated effluent increased cell-mediated cytotoxic activity with a concomitant decrease in cells responsible for antibody and cytokine production, indicating that the immune system of rainbow trout was directed towards the elimination of transformed cells, virus-infected cells and protozoan parasites at the expense of cytokine and antibody production.

Effects of physiological concentrations of heavy metals both individually and in mixtures on the viability and function of peripheral blood human leukocytes in vitro.

Among environmental contaminants recognized for their toxicity and global distribution, heavy metals are elements known to exert serious ecological consequences. Published experiments on the immunotoxic effects of metals such as methylmercury (MeHg), cadmium (Cd), and lead (Pb) were often conducted at concentrations higher than those present in the environment or those in human blood. In the present study the in vitro effects on human blood of environmentally relevant concentrations of MeHg (33-200 mug/L), Cd (3.1-16 mug/L), and Pb (75-207 mug/L) were assessed individually and in mixtures on the viability and immune competence of peripheral blood leukocytes (PBLs). At MeHg concentrations of 120 and 200 mug/L both lymphocyte proliferation, as measured by [(3)H]thymidine incorporation, and natural killer (NK) cytotoxity activity, as determined by dioctadecyloacarbocyanine, were suppressed. Our results showed an increase of intracellular thiols in lymphocytes and in monocytes at all the concentrations of metals tested. A decrease in the level of metallothionein (MT) was seen in monocytes in presence of Hg at concentration of 120 mug/L and higher. For lymphocytes, a significant increase of MT in groups containing the lower concentrations of Cd, and Hg was noted. In summary, it appears that Hg represents the most toxic metal at environmentally relevant concentrations on human peripheral mononuclear cells. The effects of Hg exposure were greater on lymphocytes and NK cells than on monocytes.

A new ultrasound protocol for extrusion of coelomocyte cells from the earthworm Eisenia fetida.

There is mounting evidence that earthworms could be used as a sentinel species for soil ecotoxicity evaluation. In this aspect, phagocytosis by coelomocytes was shown to be a sensitive biomarker of exposure to xenobiotics. In this paper, we introduce a simple method for ultrasound extrusion of earthworm coelomocytes that generates a high cell yield, does not interfere with phagocytic competence, and requires a minimum of manipulations. Coelomocytes were extruded from the earthworm Eisenia fetida using this new ultrasound method and compared with ethanol and electrical extrusion. The ultrasonic extrusion showed the highest cell recovery with 3.17 +/ -0.8 x 10(6) cells per earthworm compared with 2.22 +/- 0.8 x 10(6) cells per earthworm for electrical extrusion and 1.57 +/- 0.07 x 10(6) cells per earthworm for ethanol extrusion. No significant differences in the cell viability were observed using propidium iodide and flow cytometry with viability for extrusion with ethanol of 63.8 +/- 12.7%, electrical 76.8 +/- 7.5%, and ultrasound 68.2 +/- 7.8%. To compare the potential effect of extrusion on cell quality, the cells extruded using the three methods were subjected to an 18-h in vitro exposure to methylmercury chloride (MeHgCl; CH3HgCl) with concentrations ranging from 10(-9) to 10(-4)M. The half-maximal effective concentration (EC50) for inhibition of phagocytosis occurred between 10(-7) and 10(-6)M. We found no significant differences among the extrusion methods for the phagocytic potential of the coelomocytes. This method does not harm the worms and can certainly improve collection of coelomocytes from earthworms and therefore contribute to the development of bioassays using invertebrates.

Exposure of leopard frogs to a pesticide mixture affects life history characteristics of the lungworm Rhabdias ranae.

We tested the hypothesis that exposure of leopard frogs ( Rana pipiens) to agricultural pesticides can affect the infection dynamics of a common parasite of ranid frogs, the lungworm Rhabdias ranae. After a 21-day exposure to sublethal concentrations of a pesticide mixture composed of atrazine, metribuzin, aldicarb, endosulfan, lindane and dieldrin, or to control solutions (water, dimethyl sulfoxide), parasite-free juvenile frogs were challenged with 30 infective larvae of R. ranae. Approximately 75% of the larvae penetrated the skin and survived in both exposed and control animals, suggesting that pesticides did not influence host recognition or penetration components of the transmission process. Rather, we found that the migration of R. ranae was significantly accelerated in hosts exposed to the highest concentrations of pesticides, leading to the establishment of twice as many adult worms in the lungs of frogs 21 days post-infection. Pesticide treatment did not influence the growth of lungworms but our results indicate that they matured and reproduced earlier in pesticide-exposed frogs compared to control animals. Such alterations in life history characteristics that enhance parasite transmission may lead to an increase in virulence. Supporting evidence shows that certain components of the frog immune response were significantly suppressed after exposure to the pesticide mixture. This suggests that the immune system of anurans exerts a control over lungworm migration and maturation and that agricultural contaminants can interfere with these control mechanisms. Our results also contribute to the ongoing debate regarding the role that anthropogenic factors could play in the perplexing disease-related die-offs of amphibians observed in several parts of the world.

Effects of exposure of Mya arenaria and Mactromeris polynyma to contaminated marine sediments on phagocytic activity of hemocytes.

Two species of bivalves, Mya arenaria and Mactromeris polynima, were exposed to contaminated marine sediments from Baie des Anglais, Quebec, for a period of 10 and 12 weeks, respectively, in order to determine if there was an effect on the phagocytic activity of hemocytes from each species. These sediments contain elevated levels of both PAHs and PCBs. Uncontaminated beach sand was used as control sediments. After a period of 4 weeks, each species of bivalves were sampled and hemocyte phagocytic activity was monitored by flow cytometry. While phagocytosis by hemocytes from M. polytiyma was significantly suppressed, those from M. arenaria were not different from beach sand-exposed controls. At the end of the exposure period, the phagocytic activity of hemocytes from both species was suppressed. Physiological parameters such as mantle proteins or malondialdehyde levels, total protein and total glycogen levels in the digestive gland were not affected by exposure to contaminated sediments. Moreover, the suppression of phagocytosis was well correlated with the transfer of contaminants from the sediments to the bivalves and their subsequent bioaccumulation, as demonstrated by the PCB body burden. These results support the use of bivalves as good sentinel species to survey sediment contamination and the usefulness of hemocyte phagocytic activity as a sensitive biomarker of exposure to organic contaminants.

Phagocytic response of terrestrial and aquatic invertebrates following in vitro exposure to trace elements.

The potential of the trace elements Ag, As, Cd, Hg, Mo, Ni, Pb, Se, and Zn to inhibit the phagocytosis response of extruded coelomocytes of different worm species was tested. We used flow cytometry to evaluate the sensitivity of cell viability and phagocytic potential for Eisenia fetida, Lumbricus terrestris, Aporrectodea turgida, and Tubifex tubifex. Extruded cells were exposed 18 h in vitro to concentrations ranging from 10(-9) to 10(-4) M. Mercury was the most potent immunotoxic element, with 50% inhibition of phagocytosis occurring at concentrations between 10(-7) and 10(-6) M. Cadmium, Cu, Ni, and Zn also showed significant immunosuppressive effects with concentrations inducing 50% inhibition ranging from 10(-5) to 10(-4) M. Species-specific sensitivity varied by about a factor of 10, with no species showing a systematically higher or lower in vitro sensitivity across the range of trace elements tested.

Phagocytic activity of marine and freshwater bivalves: in vitro exposure of hemocytes to metals (Ag, Cd, Hg and Zn).

We measured non-specific immune function of various bivalves from marine (Cyrtodaria siliqua, Mactromeris polynyma, Mesosdesma arctatum, Mya arenaria, Mya truncata, Mytilus edulis, Serripes groenlandicus, Siliqua costata) and freshwater environments (Dreissena polymorpha and Elliptio complanata). We used flow cytometry to quantify the phagocytosis of fluorescent microspheres by hemocytes exposed in vitro to increasing levels of various metal compounds (AgNO(3), CdCl(2), CH(3)HgCl, HgCl(2) and ZnCl(2)). In some species, low doses of mercury (organic and inorganic) and Zn suggest a hormesis-like stimulation of phagocytic activity. At higher levels of exposure, all metals tested induced a significant dose-related inhibition of hemocyte phagocytosis. The species-specific sensitivity of the assay was determined by comparing the in vitro exposure using the metal concentration inducing a 50% suppression (EC(50)) of the phagocytic activity. Different species expressed different levels of sensitivity. Our results show the variability of the toxic response of different species within a group of similar organisms. It also highlights the need to consider species-species differences in ecotoxicological risk assessment.

Effects of in vivo exposure of Mya arenaria to organic and inorganic mercury on phagocytic activity of hemocytes.

Marine bivalves are aquatic invertebrate organisms which can be used as bioindicators in environmental monitoring. In vivo effects of mercuric chloride (HgCl(2)) and methylmercury (CH(3)HgCl) on phagocytic function of Mya arenaria hemocytes were evaluated in this study. Clams were exposed to single metal in water for up to 28 days at concentrations ranging from 10(-9) to 10(-5) M. Phagocytic activity of hemocytes was determined by uptake of fluorescent microspheres and flow cytometry. All clams exposed to 10(-5) M HgCl(2) died by day 7 of exposure. The viability of hemocytes was decreased only in clams exposed to 10(-6) M HgCl(2) for 28 days. A significant decrease in phagocytic activity of hemocytes was observed in clams exposed to 10(-6) M of HgCl(2) for 28 days. A similar pattern was observed with CH(3)HgCl, but at an earlier time. Chemical analysis performed on the tissues of the animals clearly show a greater uptake of the organic form of mercury by clams. Furthermore, a clear correlation was established between body burden of mercury and effects on phagocytic activity of hemocytes. Overall, the results of this study show that both speciations of mercury inhibited phagocytic function of Mya arenaria hemocytes following in vivo exposures.

Immunosuppression in mice fed on diets containing beluga whale blubber from the St Lawrence estuary and the Arctic populations.

In order to assess the immunotoxic potential of naturally relevant mixtures of PCBs and other organohalogens, C57Bl/6 mice were fed on diets in which lipids were replaced by blubber of beluga whales from the highly contaminated population of the Saint-Lawrence River, and the less contaminated population from the Arctic. Different ratios of blubber from both sources were mixed in order to allow a dose-response study. Mice were fed for a period of 90 days at the end of which their immunological status was monitored. For general parameters such as body weight, weight of the spleen and the thymus no significant effect of diets were observed. The immunological endpoints such as the blastic transformation of splenocytes and the spleen NK cell activity were not significantly affected by any of the diets compared to control diets. While the different cell subpopulations of peripheral blood and thymus were not affected by the diets, a significant decrease was noted in the CD8+ T cell population in the spleen of mice fed with most of the diets containing beluga blubber. Moreover, the ability of splenic cells to elicit humoral response against sheep red blood cells as well as the potential of peritoneal macrophages to perform phagocytosis were suppressed by all diets containing beluga blubbers. In summary, there was no differences between the groups fed with a blubber diet with low and high organochlorine contamination. However, a clear immunosuppression was demonstrated when these groups were compared to the group fed with beef oil. Despite the fact that we cannot exclude a possible contribution of the fatty acid composition of the beluga blubber to the immunosupression, these results suggest the sensitivity of mouse immune system towards organohalogens, and point out the toxic potential of contaminant mixtures as found in the less contaminated Arctic population.