Effects of short-term exposure to environmentally relevant concentrations of different pharmaceutical mixtures on the immune response of the pond snail Lymnaea stagnalis

Pharmaceuticals are pollutants of potential concern in the aquatic environment where they are commonly introduced as complex mixtures via municipal effluents. Many reports underline the effects of pharmaceuticals on immune system of non target species. Four drug mixtures were tested, and regrouped pharmaceuticals by main therapeutic use: psychiatric (venlafaxine, carbamazepine, diazepam), antibiotic (ciprofloxacine, erythromycin, novobiocin, oxytetracycline, sulfamethoxazole, trimethoprim), hypolipemic (atorvastatin, gemfibrozil, benzafibrate) and antihypertensive (atenolol, furosemide, hydrochlorothiazide, lisinopril). Their effects were then compared with a treated municipal effluent known for its contamination, and its effects on the immune response of Lymnaea stagnalis. Adult L. stagnalis were exposed for 3 days to an environmentally relevant concentration of the four mixtures individually and as a global mixture. Effects on immunocompetence (hemocyte viability and count, ROS and thiol levels, phagocytosis) and gene expression were related to the immune response and oxidative stress: catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), Selenium-dependent glutathione peroxidase (SeGPx), two isoforms of the nitric oxide synthetase gene (NOS1 and NOS2), molluscan defensive molecule (MDM), Toll-like receptor 4 (TLR4), allograft inflammatory factor-1 (AIF) and heat-shock protein 70 (HSP70). Immunocompetence was differently affected by the therapeutic class mixtures compared to the global mixture, which increased hemocyte count, ROS levels and phagocytosis, and decreased intracellular thiol levels. TLR4 gene expression was the most strongly increased, especially by psychiatric mixture (19-fold), while AIF-1, GR and CAT genes were downregulated. A decision tree analysis revealed that the immunotoxic responses caused by the municipal effluent were comparable to those obtained with the global pharmaceutical mixture, and the latter shared similarity with the antibiotic mixture. This suggests that pharmaceutical mixtures in municipal effluents represent a risk for gastropods at the immunocompetence levels and the antibiotic group could represent a model therapeutic class for municipal effluent toxicity studies in L. stagnalis.

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.

Immunotoxicity of surface waters contaminated by municipal effluents to the snail Lymnaea stagnalis

The immunotoxic effects of surface waters contaminated by a municipal effluent dispersion plume were examined in the snail Lymnaea stagnalis. Snails were exposed to surface waters where changes in hemocyte counts, viability, levels of reactive oxygen species (ROS), reduced thiols and phagocytic activity were tracked following exposure periods of 3h and 3 and 7d. Changes in mRNA expression of some genes in the hemocytes were also assessed after 7d of exposure, as follows: genes coding for catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GSR), selenium-dependent glutathione peroxidase (SeGPX), two isoforms of the nitric oxide synthetase (NOS1 and NOS2), molluscan defensive molecule (MDM), toll-like receptor 4 (TLR4), allograft inflammatory factor-1 (AIF), and heat-shock protein 70 (HSP70). At the sites closest to the discharge point, exposure led to impaired hemocyte viability and intracellular thiol levels and also an increase of hemocyte count, ROS levels and phagocytosis. Phagocytosis and ROS levels in hemocytes were correlated with heterotrophic bacterial counts in snails. We found four genes with increased mRNA expression as a response to exposure of municipal wastewaters: TLR4 (6-fold), HSP70 (2-fold), SeGPx (4-fold) and CAT (2-fold). Immunocompetence responses were analyzed by canonical analysis to seek out relationships with mRNA expression of the genes involved in stress, pattern recognition, cellular and humoral responses. The data revealed that genes involved in oxidative stress were strongly involved with immunocompetence and that the resulting immune responses were influenced both by the bacterial and pollutant loadings of the effluent.

Bioavailability and immunotoxicity of silver nanoparticles to the freshwater mussel Elliptio complanata

The purpose of this study was to examine the effects of Ag nanoparticles (nAg) of two different sizes (20 and 80 nm) and Ag(+) on the immune system of the freshwater mussel Elliptio complanata. Mussels were exposed to increasing concentrations of nAg and dissolved Ag (AgNO3) for 48 h at 15°C and concentration of 0, 0.8, 4, or 20 μg/L. Immunocompetence was determined by hemocyte viability, phagocytosis, and cell cytotoxicity. Ag tissue loadings and levels of metallothioneins (MT), lipid peroxidation (LPO), and labile zinc (Zn) were also determined. Results revealed first that 20- and 80-nm nAg readily formed aggregates in freshwater. Ag was detected in soft tissues with each form of Ag with bioconcentration factors of 20, 9, and 7 for Ag(+), 20-nm nAg, and 80-nm nAg, respectively. Significant induction in phagocytosis and decreased cell cytotoxicity were observed. All forms of Ag were able to induce LPO in gills and digestive glands at concentrations below those from the initial fraction of dissolved Ag. The effects of nAg on MT levels in mussels were not discernible from those of dissolved Ag, but the 80-nm was 25-fold more potent than 20-nm nAg in inducing MT. Multivariate analysis revealed that the global responses of the 20- and 80-nm nAg were generally similar to those of dissolved Ag. Data also demonstrated that nAg are bioavailable for mussels where the immune system is a target during early exposure to nanoparticles.

In vitro immunotoxicity of environmentally representative antibiotics to the freshwater mussel Elliptio complanata

The separate and combined in vitro toxic effects of antibiotics (ciprofloxacin, erythromycin, novobiocin, oxytetracycline, sulfamethazole and trimethoprim) commonly found in urban wastewater effluents were assessed on the immune parameters of Elliptio complanata at environmentally relevant concentrations. The observed responses were then compared to those produced by the physicochemical-treated wastewater effluent of a major city before and after the removal of microorganisms. Most of the selected antibiotics, separately and as mixture, induced changes in immune responses. The removal of microorganisms and fine particles from the effluent increased or decreased the resulting immunotoxic effects, depending of the observed parameter. The immunotoxic effects of erythromycin, sulfamethoxazole and trimethoprim were closely associated to the antibiotic mixture and the filtered effluent. In conclusion, the data revealed that the removal of fine particles and microorganisms from municipal effluents can alter the toxic nature of the effluent that is closely associated with the cumulative effects of antibiotics.

An European Organisation for Research and Treatment of Cancer phase I study of lapatinib and docetaxel as neoadjuvant treatment for human epidermal growth factor receptor 2 (HER2) positive locally-advanced/inflammatory or large operable breast cancer

BACKGROUND

Lapatinib is an effective anti-HER2 therapy in advanced breast cancer and docetaxel is one of the most active agents in breast cancer. Combining these agents in pre-treated patients with metastatic disease had previously proved challenging, so the primary objective of this study aimed to determine the maximum tolerated dose (MTD) in treatment-naive patients, by identifying acute dose-limiting toxicities (DLT) during cycle 1 in the first part of a phases 1-2 neoadjuvant European Organisation for Research and Treatment of Cancer (EORTC) trial.

PATIENTS AND METHODS

Patients with large operable or locally-advanced HER2 positive breast cancer were treated with continuous lapatinib, and docetaxel every 21days for 4 cycles. Dose levels (DLs) were: 1000/75, 1250/75, 1000/85, 1250/85, 1000/100 and 1250/100 (mg/day)/(mg/m(2)).

RESULTS

Twenty-one patients were included. Two DLTs occurred at dose level 5 (1000/100); one grade 4 neutropenia ≥ 7days and one febrile neutropenia. A further 3 patients were therefore treated at the same dose with prophylactic granulocyte-colony stimulating factor (G-CSF), and 3 patients at dose level 6. No further DLTs were observed.

CONCLUSIONS

Our recommended dose for phase II is lapatinib 1000mg/day and docetaxel 100mg/m(2) with G-CSF in HER2 positive non-metastatic breast cancer. The dose of lapatinib should have been 1250mg/day but we were mindful of the high rate of treatment discontinuation in GeparQuinto with lapatinib 1250mg/day combined with docetaxel. No grade 3-4 diarrhoea was observed. Pharmacodynamics analysis suggests that concomitant medications altering P-glycoprotein activity (in addition to lapatinib) can modify toxicity, including non-haematological toxicities. This needs verification in larger trials, where it may contribute to understanding the sources of variability in clinical toxicity and treatment discontinuation.

[Regional procedure of blood products transport by emergency medical services]

Transfusions are exceptional while patients are rushed to hospital for sanitary reasons. The quality of care requires the collaboration with different partners (samu, blood bank centre, haemovigilance correspondents…). In response to dysfunctions that occurred during transports for sanitary reasons we have drawn up a regional procedure, which specifies how to get and use blood products. This procedure harmonizes our medical practice, states the role of the different participants (traceability of blood samples of immunohaematology tests, etc.), including a part dedicated to identity vigilance. The expected impacts of this procedure are: the decrease of dysfunctions and of destructions of red blood cells, the improvement of security while patients are transfused.

Chronic mTOR inhibition by rapamycin induces muscle insulin resistance despite weight loss in rats

BACKGROUND AND PURPOSE

mTOR inhibitors are currently used as immunosuppressants in transplanted patients and as promising anti-cancer agents. However, new-onset diabetes is a frequent complication occurring in patients treated with mTOR inhibitors such as rapamycin (Sirolimus). Here, we investigated the mechanisms associated with the diabetogenic effects of chronic Sirolimus administration in rats and in in vitro cell cultures.

EXPERIMENTAL APPROACH

Sirolimus was administered to rats fed either a standard or high-fat diet for 21 days. Metabolic parameters were measured in vivo and in ex vivo tissues. Insulin sensitivity was assessed by glucose tolerance tests and euglycaemic hyperinsulinaemic clamps. Rapamycin effects on glucose metabolism and insulin signalling were further evaluated in cultured myotubes.

KEY RESULTS

Sirolimus induced a decrease in food intake and concomitant weight loss. It also induced specific fat mass loss that was independent of changes in food intake. Despite these beneficial effects, Sirolimus-treated rats were glucose intolerant, hyperinsulinaemic and hyperglycaemic, but not hyperlipidaemic. The euglycaemic hyperinsulinaemic clamp measurements showed skeletal muscle is a major site of Sirolimus-induced insulin resistance. At the molecular level, long-term Sirolimus administration attenuated glucose uptake and metabolism in skeletal muscle by preventing full insulin-induced Akt activation and altering the expression and translocation of glucose transporters to the plasma membrane. In rats fed a high-fat diet, these metabolic defects were exacerbated, although Sirolimus-treated animals were protected from diet-induced obesity.

CONCLUSIONS AND IMPLICATIONS

Taken together, our data demonstrate that the diabetogenic effect of chronic rapamycin administration is due to an impaired insulin action on glucose metabolism in skeletal muscles.

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.

Lower extremity surgery in muscular dystrophy

INTRODUCTION

The natural progression of neuromuscular diseases results in inevitable musculotendinous contractures, most often in spite of early treatment. Surgery corrects this. The aim of this study was to evaluate the results of tendon surgery in these cases.

MATERIALS AND METHODS

Twenty children with muscular dystrophy underwent hip surgery (tensor fascia lata tenectomy, rectus femoris and sartorius tenotomy), knee surgery (gracilis, semitendinosus and semimembranosus tenotomies) and/or ankle surgery (lengthening or tenotomy of the Achilles tendon with or without posterior tibial tendon transfer). Articular range of motion was evaluated preoperatively, 6 months after surgery, at 1 year and at the final follow-up (7.4 years).

RESULTS

Three children underwent surgery before they had lost their walking capacity, eight soon afterwards, and nine long afterwards. Surgery was bilateral in all cases: 38 hips, 12 knees and 36 ankles with 22 posterior tibial tendon transfers. Hip extension, which was limited by a 30° flexion contracture improved to 10° and stabilized at 14° at the final follow-up. Adduction which was -19° before surgery increased to 35° and had stabilized at 32° at the final follow-up. Knee flessum (38°) was only slightly improved (24°) and had regressed at the final follow-up. Equinus deformity (42°) was corrected to 9° of dorsal flexion with a slight loss (2°) at the final follow-up. Varus was improved from 11° to 6°, but this had regressed at 1 year (10°) and at the final follow-up (11°). Achilles tendon tenotomies resulted in 28° of dorsal flexion at 6 months compared to 20° with lengthening. Correction of varus was better with posterior tibial tendon transfer at 6 months, 1 year and at the final follow-up (11° versus 5°). In the three patients who underwent surgery before losing their walking ability, one continued walking for 1 year and two for 6 months. None of the eight patients who underwent surgery soon after losing ambulation were able to regain walking. All patients were able to continue device assisted upright positioning for a mean 3 years.

DISCUSSION

Hip and ankle surgery can release contractures. In the knees, surgery should be restricted to cases with knee flessum greater than 30°. The best results are obtained with extensive m. tensor fascia lata tenectomy and posterior tibial tendon transfer. Achilles tendon tenotomy results in better recovery of dorsal flexion. Surgery is indicated when contractures are severe and the patient is no longer able to walk. The aim should not be to continue walking but to release contractures, so that the patient can continue assisted upright positioning as long as possible. Especially in cases of asymmetric contractures, surgery can help slow the progression of scoliosis.

Evidence of neuroendocrine disruption in freshwater mussels exposed to municipal wastewaters

The purpose of this study was to test the hypothesis that exposure to municipal effluents can disrupt the neuroendocrine system in Elliptio complanata freshwater mussels. The capacity of ozonation to mitigate these effects was also examined. Mussels were exposed for 14 days to a continuous flow of increasing concentrations of the effluent before and after ozonation. Neuroendocrinal effects were examined by tracking changes in acetylcholinesterase, glutamate, gamma-aminobutyrate, serotonin, dopamine and their respective adenylcyclase activities in synapse membranes, monoamine oxidase and vitellogenin-like proteins. Oxidative stress and damage were examined by superoxide dismutase and lipid peroxidation, respectively, in the visceral tissues. The results revealed that the exposure of freshwater mussels increased the levels of vitellogenin-like proteins in both the primary-treated and ozonated effluents, dopamine and glutamate, and decreased the turnover of the neurostimulant acetylcholine. Moreover, these endpoints were significantly correlated with oxidative stress and damage. A canonical analysis of the responses revealed that dopamine and the neuroexcitatory neuromediators--acetylcholesterase and glutamate--were the endpoints more strongly related with oxidative stress and damage. Mussel morphology and estrogenic biomarkers (vitellogenin-like proteins, gonad lipid stores) were also significantly related, albeit to a lesser extent, to oxidative stress and damage. In general, ozone treatment was not sufficient to mitigate the observed neuroendocrinal effects in freshwater mussels. We conclude that the continuous exposure of freshwater mussels to municipal wastewater effluents leads to neuroendrocinal alterations and to oxidative stress.

Alterations in DNA metabolism in Elliptio complanata mussels after exposure to municipal effluents

This study sought to examine the genotoxic potential in Elliptio complanata freshwater mussels exposed to a physically and chemically treated municipal effluent before and after ozone treatment. Mussels were continuously exposed to increasing concentrations of the effluents for 14 days. Genotoxicity was determined by tracking changes in key enzymes for purine and pyrimidine synthesis (dehydrofolate reductase and aspartate transcarbamoylase), catabolism of purines (xanthine oxido-reductase) and DNA strand-break levels as determined by the alkaline precipitation assay. Other biomarkers related to xenobiotic biotransformation (cytochrome P4503A and glutathione S-transferase activities), metal metabolism (labile zinc and redox state of metathioneins) and oxidative stress (superoxide dismutase activity) were also determined in the mussels. The data revealed that dehydrofolate reductase activity was reduced by the initial effluent and increased by the ozonated effluent. Aspartate transcarbamoylase activity was significantly induced only with the ozonated effluent. The levels of DNA strand breaks responded in a biphasic manner in mussels exposed to the physically and chemically treated effluent where an initial decrease was observed at a low effluent concentration (3% v/v) followed by an increase in DNA strand breaks at a higher effluent concentration (20%). This response pattern was lost in the ozonated effluent, where only a decrease in DNA breaks was found. Xanthine oxidoreductase activity was not significantly affected but did correlate significantly with dehydrofolate reductase activity. Multivariate factorial and canonical analyses revealed that oxidative stress and metal/xenobiotic metabolism markers were strongly correlated with DNA strand breaks in mussels, suggesting that the presence of metals (zinc) and planar hydroxylated hydrocarbons present in these effluents were strong contributors to the observed response. We conclude that municipal effluents contain a complex mixture of pollutants that could modulate DNA synthesis and repair mechanisms in mussels.

Assessing survival benefits from lung transplantation

INTRODUCTION

Published studies used several methods to assess the impact of lung transplantation on patient survival. To interpret the results of these studies, a basic understanding of the models used and underlying hypotheses is required.

CURRENT KNOWLEDGE

The most often used method consists in assessing the survival of waiting-list patients and measuring the impact of lung transplantation on the baseline hazard (instantaneous risk) for death, usually with a Cox proportional hazards model. This strategy involves strong assumptions about the link between the baseline hazard in waiting-list patients and lung transplant recipients. Whether these assumptions are true is extremely difficult to establish. Some studies compared predicted survival without transplantation to observed survival after transplantation. We recently reported a new method in which predicted survival without transplantation is compared to predicted survival after transplantation.

PERSPECTIVES

All the methods described to date evaluate only the impact of transplantation on patient survival. The concomitant use of other markers such as respiratory function or quality of life would produce a more detailed picture of lung transplantation benefits.

CONCLUSION

Evaluating the benefits of lung transplantation involves the use of complex statistical methods. The results should be considered with circumspection, and none of the methods described to date allows definitive conclusions.

High contrast 40Gbit/s optical modulation in silicon

Data interconnects are on the verge of a revolution. Electrical links are increasingly being pushed to their limits with the ever increasing demand for bandwidth. Data transmission in the optical domain is a leading candidate to satisfy this need. The optical modulator is key to most applications and increasing the data rate at which it operates is important for reducing power consumption, increasing channel bandwidth limitations and improving the efficiency of infrastructure usage. In this work silicon based devices of lengths 3.5mm and 1mm operating at 40Gbit/s are demonstrated with extinction ratios of up to 10dB and 3.5dB respectively. The efficiency and optical loss of the phase shifter is 2.7V.cm and 4dB/mm (or 4.5dB/mm including waveguide loss) respectively.

42.7 Gbit/s electro-optic modulator in silicon technology

CMOS-compatible optical modulators are key components for future silicon-based photonic transceivers. However, achieving low modulation voltage and high speed operation still remains a challenge. As a possible solution, the silicon-organic hybrid (SOH) platform has been proposed. In the SOH approach the optical signal is guided by a silicon waveguide while the electro-optic effect is provided by an organic cladding with a high χ(2)-nonlinearity. In these modulators the optical nonlinear region needs to be connected to the modulating electrical source. This requires electrodes, which are both optically transparent and electrically highly conductive. To this end we introduce a highly conductive electron accumulation layer which is induced by an external DC "gate" voltage. As opposed to doping, the electron mobility is not impaired by impurity scattering. This way we demonstrate for the first time data encoding with an SOH electro-optic modulator. Using a first-generation device at a data-rate of 42.7 Gbit/s, widely open eye diagrams were recorded. The measured frequency response suggests that significantly larger data rates are feasible.

Growth and posture control strategies in Fagus sylvatica and Acer pseudoplatanus saplings in response to canopy disturbance

BACKGROUND AND AIMS

Forest tree saplings that grow in the understorey undergo frequent changes in their light environment to which they must adapt to ensure their survival and growth. Crown architecture, which plays a critical role in light capture and mechanical stability, is a major component of sapling adaptation to canopy disturbance. Shade-adapted saplings typically have plagiotropic stems and branches. After canopy opening, they need to develop more erect shoots in order to exploit the new light conditions. The objective of this study was to test whether changes in sapling stem inclination occur after canopy opening, and to analyse the morphological changes associated with stem reorientation.

METHODS

A 4-year canopy-opening field experiment with naturally regenerated Fagus sylvatica and Acer pseudoplatanus saplings was conducted. The appearance of new stem axes, stem basal diameter and inclination along the stem were recorded every year after canopy opening.

KEY RESULTS

Both species showed considerable stem reorientation resulting primarily from uprighting (more erect) shoot movements in Fagus, and from uprighting movements, shoot elongation and formation of relay shoots in Acer. In both species, the magnitude of shoot uprighting movements was primarily related to initial stem inclination. Both the basal part and the apical part of the stem contributed to uprighting movements. Stem movements did not appear to be limited by stem size or by stem growth.

CONCLUSIONS

Stem uprighting movements in shade-adapted Fagus and Acer saplings following canopy disturbance were considerable and rapid, suggesting that stem reorientation processes play a significant role in the growth strategy of the species.

International standardisation work on the measurement of radon in air and water

Radon is considered to be the main source of human exposure to natural radiation. As stated by the World Health Organization, the exposure due to the inhalation of indoor radon is much greater than the one via the ingestion of water as radon degasses from water during handling. In response to these concerns about the universal presence of radon, environmental assessment studies are regularly commissioned to assess the radon exposure of public and workers. The credibility of such studies relies on the quality and reliability of radon analysis as well as on the sample representativeness of the radiological situation. The standard-setting approach, based on consensus, seemed to lend itself to a settlement of technical aspects of potential comparison. At present, two Working Groups of the International Standardization Organization are focussing on drafting standards on radon and its decay products measurement in air and water. These standards, which aim for a set of rigorous metrology practices, will be useful for persons in charge of the initial characterisation of a site with respect to natural radioactivity as well as to those performing the routine surveillance of specific sites.

Intensive exploitation of a karst aquifer leads to Cryptosporidium water supply contamination

Groundwater from karst aquifers is an important source of drinking water worldwide. Outbreaks of cryptosporidiosis linked to surface water and treated public water are regularly reported. Cryptosporidium oocysts are resistant to conventional drinking water disinfectants and are a major concern for the water industry. Here, we examined conditions associated with oocyst transport along a karstic hydrosystem, and the impact of intensive exploitation on Cryptosporidium oocyst contamination of the water supply. We studied a well-characterized karstic hydrosystem composed of a sinkhole, a spring and a wellbore. Thirty-six surface water and groundwater samples were analyzed for suspended particulate matter, turbidity, electrical conductivity, and Cryptosporidium and Giardia (oo)cyst concentrations. (Oo)cysts were identified and counted by means of solid-phase cytometry (ChemScan RDI(®)), a highly sensitive method. Cryptosporidium oocysts were detected in 78% of both surface water and groundwater samples, while Giardia cysts were found in respectively 22% and 8% of surface water and groundwater samples. Mean Cryptosporidium oocyst concentrations were 29, 13 and 4/100 L at the sinkhole, spring and wellbore, respectively. Cryptosporidium oocysts were transported from the sinkhole to the spring and the wellbore, with respective release rates of 45% and 14%, suggesting that oocysts are subject to storage and remobilization in karst conduits. Principal components analysis showed that Cryptosporidium oocyst concentrations depended on variations in hydrological forcing factors. All water samples collected during intensive exploitation contained oocysts. Control of Cryptosporidium oocyst contamination during intensive exploitation is therefore necessary to ensure drinking water quality.

Evidence of feminization in wild Elliptio complanata mussels in the receiving waters downstream of a municipal effluent outfall

The endocrine-disrupting activity of municipal effluents has the potential to alter the reproductive system and induce feminization to aquatic organisms. The purpose of this study was to examine the sex ratio, vitellogenin (Vtg)-like proteins, serotonin, arachidonate cyclooxygenase (COX) activity and dopamine status in wild mussels living at sites upstream and downstream of two municipal effluent outfalls in the Mille-Îles River (Quebec, Canada). Gonad integrity was also studied by monitoring the gonado-somatic index (GSI), the activity of the rate-limiting enzyme aspartate transcarbamoylase (ATC) for purine synthesis, and changes in lipid peroxidation (LPO). The results showed that the proportion of females was dramatically increased from 30% at the upstream sites to 80% at the downstream sites. The levels of Vtg-like proteins were significantly elevated in the male mussels only. Male mussels downstream of the municipal effluent plumes expressed female-specific protein bands (Vtg-like), as determined by high-resolution gel electrophoresis and silver staining. The serotonin/dopamine ratio was significantly decreased in the downstream mussels, indicating that the gonad was in a state of early vitellogenesis. However, this change was not accompanied by changes in ATC, suggesting no significant egg production was underway; this was confirmed by the observation that the downstream mussels displayed significantly low GSIs. GSIs were rather dependent on the serotonin/dopamine ratio (r=0.44; p<0.001), while Vtg-like proteins were dependent on dopamine levels (r=0.50; p<0.001). The increase in COX activity at the downstream sites and its close relationship with increased serotonin levels suggest a concomitant serotonergic signalling in addition to VTG production. The production of Vtg-like proteins combined with the serotonergic effects of the municipal effluents was associated with oxidative damage (LPO) in the gonad. This study provides the first evidence of feminization in wild mussel populations and the disruption in gonad physiology by exposure to municipal effluents.