Former uranium mine-induced effects in caged roach: a multiparametric approach for the evaluation of in situ metal toxicity

Ecotoxicology - To characterize environmental risks linked to former uranium mines in the Limousin region of France, a study was conducted on fish health effects from uranium releases. Two private...     

Hyaluronidase activity in serum of patients with monoclonal gammapathy

Hyaluronidase and hyaluronic acid, two substances thought to be strongly implicated in carcinogenesis, were assessed in the plasma of 35 patients with newly documented monoclonal gammapathy and in 25 control patients. A significant increase was found in plasma hyaluronidase activity in the patients with monoclonal gammapathy. A statistically significant positive correlation was found between hyaluronidase activity and monoclonal immunoglobulin levels in plasma. An increase in serum hyaluronidase activities may be a response to the deleterious effect of hyaluronic acid in cell migration and tumor progression. Further studies are needed to assess the value of hyaluronidase activity as a marker of tumor progression.     

Tobacco: a potential inductor of lipid peroxidation of the human spermatozoon membrane?

OBJECTIVE: To determine the membrane lipid peroxidation of human spermatozoon in a cohort of smokers in comparison of never-smokers. MATERIALS AND METHODS: Malondialdehyde (MDA), a stable product of the membrane lipid peroxidation, was assessed in 25 smokers and in 17 never-smokers. In parallel, an evaluation of sperm characteristics was realized for all the studied patients. RESULTS: For the first time, between smokers and never-smokers, a significative increase of MDA concentrations was found by the U-Mann and Whitney test (0.118 +/- 0.176 vs 0.0392 +/- 0.0117 nmol/10(6) spermatozoa), a decrease of the forward motility (grade A), (18 +/- 8 vs 25 +/- 8%) and total sperm count (265.56 +/- 186.96 x 10(6) vs 399.30 +/- 322.23 x10(6)), and also an increase of tapering heads (6 +/- 4 vs 2 +/- 2%) or morphological stress pattern cells (39 +/- 6 vs 24 +/- 5%). In the smokers group, negative significative correlations were found by the non-parametric Spearman test between the MDA concentrations and the sperm count per mL (r=-0.767, p<0.001), the total sperm count (r=-0.656, p<0.001) and the percentage of normal morphology (r=-0.644, p<0.001). CONCLUSIONS: Given of deleterious effects of tobacco in a large panel of human cells and specially on the male gametes, the increase of spermatozoon membrane MDA concentrations and the sperm abnormalities found in the group of smokers may be linked to cigarette smoking.     

Leg muscle vibration modulates bodily self-consciousness: integration of proprioceptive, visual, and tactile signals

Behavioral studies have used visuo-tactile conflicts between a participant's body and a visually presented fake or virtual body to investigate the importance of bodily perception for self-consciousness (bodily self-consciousness). Illusory self-identification with a fake body and changes in tactile processing--modulation of visuo-tactile cross-modal congruency effects (CCEs)--were reported in previous findings. Although proprioceptive signals are deemed important for bodily self-consciousness, their contribution to the representation of the full body has not been studied. Here we investigated whether and how self-identification and tactile processing (CCE magnitude) could be modified by altering proprioceptive signals with 80-Hz vibrations at the legs. Participants made elevation judgments of tactile cues (while ignoring nearby lights) during synchronous and asynchronous stroking of a seen fake body. We found that proprioceptive signals during vibrations altered the magnitude of self-identification and mislocalization of touch (CCE) in a synchrony-dependent fashion: we observed an increase of self-identification and CCE magnitude during asynchronous stroking. In a second control experiment we studied whether proprioceptive signals per se, or those from the lower limbs in particular, were essential for these changes. We applied vibrations at the upper limbs (which provide no information about the position of the participant's body in space) and in this case observed no modulation of bodily self-consciousness or tactile perception. These data link proprioceptive signals from the legs that are conveyed through the dorsal column-medial lemniscal pathway to bodily self-consciousness. We discuss their integration with bodily signals from vision and touch for full-body representations.     

Juvenile roach (<Emphasis Type="Italic">Rutilus rutilus</Emphasis>) increase their anaerobic metabolism in response to copper exposure in laboratory conditions

This study aims to determine the potential impairment of cell energy synthesis processes (glycolysis and respiratory chain pathways) by copper in juvenile roach at different regulation levels by using a multi-marker approach. Juvenile roach were exposed to 0, 10, 50, and 100 µg/L of copper for 7 days in laboratory conditions. The glycolysis pathway was assessed by measuring the relative expression levels of 4 genes encoding glycolysis enzymes. The respiratory chain was studied by assessing the electron transport system and cytochrome c oxidase gene expression. Muscle mitochondria ultrastructure was studied, and antioxidant responses were measured. Furthermore, the main energy reserves—carbohydrates, lipids, and proteins—were measured, and cellular energy was evaluated by measuring ATP, ADP, AMP and IMP concentrations. This study revealed a disturbance of the cell energy metabolism due to copper exposure, with a significant decrease in adenylate energy charge in roach exposed to 10 μg/L of copper after 1 day. Moreover, ATP concentrations significantly decreased in roach exposed to 10 μg/L of copper after 1 day. This significant decrease persisted in roach exposed to 50 µg/L of copper after 7 days. AMP concentrations increased in all contaminated fish after 1 day of exposure. In parallel, the relative expression of 3 genes encoding for glycolysis enzymes increased in all contaminated fish after 1 day of copper exposure. Focusing on the respiratory chain, cytochrome c oxidase gene expression also increased in all contaminated fish at the two time-points. The activity of the electron transport system was not disturbed by copper, except in roach exposed to 100 µg/L of copper after 1 day. Copper induced a metabolic stress. Juvenile roach seemed to respond to the ensuing high energy demand by increasing their anaerobic metabolism, but the energy produced by the anaerobic metabolism is unable to compensate for the stress induced by copper after 7 days. This multi-marker approach allows us to reach a greater understanding of the effects of copper on the physiological responses of juvenile roach.     

Preliminary investigation of multi-biomarker responses in three-spined stickleback (<Emphasis Type="Italic">Gasterosteus aculeatus</Emphasis> L.) sampled in contaminated streams

Recently, the three-spined stickleback (Gasterosteus aculeatus L.) has been proposed as a suitable fish species for detecting both androgen- and estrogen-induced endocrine disruption by environmental pollutants. This relatively pollution-tolerant fish is present in most European streams and small rivers but also coastal and estuarian areas. The purpose of the present field study was to determine the extent to which multiple biomarkers in this fish species could distinguish between streams with different pollution levels. Sticklebacks were sampled in French rivers characterised by various urban, industrial or agricultural contaminations and in outdoor lotic mesocosms as reference site. Physiological parameters including condition factor and liver somatic index, biotransformation enzymes such as 7-ethoxyresorufin-O-deethylase (EROD) and glutathione-S-transferase, antioxidant enzymes including glutathione peroxidase and total glutathione (GSH) content and lipoperoxidation (as TBARS) showed several differences between sites. For example, fish from an heavily contaminated stream exhibited a 9-fold EROD induction associated to a decrease of GSH and a 3-fold increase of TBARS content in comparison to fish from uncontaminated sites. When fish were transferred from polluted river to clean water, some of these biomarkers rapidly returned to basal levels found in fish in the reference site while others, like TBARS levels were still high after 2 weeks of depuration. Based on multivariate analyses, the battery of biomarkers proved to differentiate all sites, with a very good classification rate for highly contaminated streams. Influence of fish gender and sampling period on biomarker responses was also observed and is discussed. The results of this field study provide additional support for the use of stickleback for in situ multi-biomarker assessment.     

Copper-induced oxidative stress in three-spined stickleback: relationship with hepatic metal levels

The aim of this study was to characterise biomarker responses in three-spined sticklebacks exposed to copper. For this purpose, adult sticklebacks were exposed for 3 weeks to copper sulphate at 0, 25, 100 and 200μgL(-1) as Cu. At days 4, 8, 12 and 21, several parameters were measured including liver, gonad and spleen somatic indexes, hepatic biomarkers (catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione (GSH), glutathione-S-transferase (GST) and 7-ethoxyresorufin-O-deethylase (EROD)) and hepatic copper and zinc concentrations. Copper induced a rapid and transient increase of antioxidant enzymes and a depletion of glutathione content during the first 8 days of exposure. Significant copper and zinc accumulation in fish liver were observed for the two higher exposure concentrations after 8 and 12 days, respectively. This study showed that copper induced an oxidative stress in fish liver before significant metal accumulation in the liver could be detected, suggesting the involvement of differential mechanisms in copper uptake and metabolism. Three-spined stickleback appears to be a sensitive model to study oxidative stress induced by metals.     

Experimental changes in bodily self-consciousness are tuned to the frequency sensitivity of proprioceptive fibres

Several lines of evidence suggest an important implication of proprioceptive signals in bodily self-consciousness. By manipulating proprioceptive signals using muscle vibration, here, we investigated whether such effects depend on the vibration frequency by testing three different vibratory stimuli applied at the lower limbs (20, 40 and 80 Hz). We thus explored whether frequency-specific proprioceptive interference that has been reported in postural or motor tasks will also be found for measures of bodily self-consciousness. Self-identification (questionnaires) and visuotactile integration (asking participants to make tactile discriminations) were quantified during synchronous and asynchronous stroking conditions that are known to manipulate bodily self-consciousness. We found that even though muscle vibrations were applied at the same body location in all cases, 20 Hz vibrations did not alter the magnitude of self-identification and visuotactile integration, whereas 40 and 80 Hz vibrations did. These frequency-specific effects extend earlier vibration effects on motor and postural tasks to bodily self-consciousness. We suggest that the observed changes in bodily self-consciousness are due to altered proprioceptive signals from the lower limbs and that these changes depend on the tuning of Ia fibres to muscle vibration.     

Effects of attentional focus on postural sway in children and adults

The present study examined, in children aged 4–11 and in adults, the postural control modifications when attention was oriented voluntary on postural sway. Since (1) there are less attentional resources in children than in adults, (2) the selective attention processing improves with age, i.e., children use a different strategy to focus their attention than adults, and (3) adults’ postural stability decreases when attention is focused on postural sway, we hypothesized that postural stability was less affected in children than in adults when attention was focused on postural sway. Fourty four children aged 4- to 11-year-old and 11 adults participated in the experiments. The postural control task was executed in a Romberg position. Two experimental conditions were presented to the subjects, (1) to look at a video on a TV screen without instruction about the posture, and (2) to fixate a cross placed at the center of the TV screen with the instruction to remain as stable as possible. Postural performance was measured by means of a force platform. Results from this study (1) confirmed a non-monotonic improvement of postural stability during the ontogenetic period without reaching the adults’ level at the age of 11, (2) suggested that children, aged 4–11, are able to focus their attention on the control of posture, and (3) showed that the automatic control of posture increases postural stability since the age of 4.     

In situ effects of metal contamination from former uranium mining sites on the health of the three-spined stickleback (<Emphasis Type="Italic">Gasterosteus aculeatus</Emphasis>, L.)

Human activities have led to increased levels of various pollutants including metals in aquatic ecosystems. Increase of metallic concentrations in aquatic environments represents a potential risk to exposed organisms, including fish. The aim of this study was to characterize the environmental risk to fish health linked to a polymetallic contamination from former uranium mines in France. This contamination is characterized by metals naturally present in the areas (manganese and iron), uranium, and metals (aluminum and barium) added to precipitate uranium and its decay products. Effects from mine releases in two contaminated ponds (Pontabrier for Haute-Vienne Department and Saint-Pierre for Cantal Department) were compared to those assessed at four other ponds outside the influence of mine tailings (two reference ponds/department). In this way, 360 adult three-spined sticklebacks (Gasterosteus aculeatus) were caged for 28 days in these six ponds before biomarker analyses (immune system, antioxidant system, biometry, histology, DNA integrity, etc.). Ponds receiving uranium mine tailings presented higher concentrations of uranium, manganese and aluminum, especially for the Haute-Vienne Department. This uranium contamination could explain the higher bioaccumulation of this metal in fish caged in Pontabrier and Saint-Pierre Ponds. In the same way, many fish biomarkers (antioxidant and immune systems, acetylcholinesterase activity and biometric parameters) were impacted by this environmental exposure to mine tailings. This study shows the interest of caging and the use of a multi-biomarker approach in the study of a complex metallic contamination.