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...     

Adiponectin gene polymorphisms and adiponectin levels are independently associated with the development of hyperglycemia during a 3-year period: the epidemiologic data on the insulin resistance syndrome prospective study

The plasma concentration of the adipocyte-derived peptide adiponectin is decreased in patients with obesity and type 2 diabetes. The adiponectin gene is located on chromosome 3q27, where a diabetes susceptibility locus has been mapped. Adiponectin gene polymorphisms (single nucleotide polymorphisms [SNPs]) have been associated with BMI, insulin sensitivity, and type 2 diabetes in some cross-sectional studies. Our aim was to assess the contribution of these SNPs in the development of features of the insulin resistance syndrome in a 3-year prospective study in approximately 4,500 French Caucasian subjects from the Epidemiologic Data on the Insulin Resistance Syndrome (DESIR) cohort. For subjects who were normoglycemic at baseline, the 3-year risk of becoming hyperglycemic (diabetes or impaired fasting glucose) was affected by two SNPs: G-11391A and T45G. For G-11391A, the risk was increased in GA carriers (odds ratio [OR] adjusted for sex [versus GG] = 1.60 [95% CI 1.16-2.20]; P = 0.004). For T45G, it was increased in GG carriers (OR [versus TT] = 2.71 [1.31-5.60]; P = 0.007). After 3 years, GG subjects had a greater increase in BMI (P = 0.009) and waist-to-hip ratio (P = 0.007). Adiponectin levels at baseline were associated with the development of hyperglycemia (P = 0.005), but the predictive effects on the risk for hyperglycemia were independent of adiponectin genotypes. In conclusion, in the DESIR study, variations at the adiponectin locus affect body weight gain, body fat distribution, and onset of hyperglycemia, as well as adiponectin levels. Adiponectin gene SNPs may have several phenotypic effects that co-occur with the development of the metabolic syndrome.     

Humoral immune factors modulated by copper and chitosan in healthy or parasitised carp (Cyprinus carpio L.) by Ptychobothrium sp. (Cestoda)

As an environmental protection point of view, the potential toxicity of chitosan on aquatic animal health, alone or associated with copper must be investigated. Fish possess defence mechanisms to counteract the impact of toxics. The non-cellular and non-specific immune defences (total immunoglobulin, ceruloplasmin, lysozyme and potential killing activity of phagocytic cells) can be modulated by the potential environmental pollutants but also by natural stimulants such as bacteria, viruses or parasites. In this study, we investigate the potential toxicity of copper (0.1 and 0.25 mg/L) or chitosan (75 and 150 mg/L) and the combination copper and chitosan (0.1 and 75 mg/L, respectively) on two groups of carp: healthy or parasitised by Ptychobothrium sp. Fish exposed to water-soluble chitosan for 96 h had significantly high levels of natural antibodies in plasma. Moreover, activities of lysozyme and ceruloplasmin were also increased in plasma after the same treatment. The exposition of fish to copper have shown apparently contradictory effects on the immune parameters measured but, significant increase of this bacteriolytic activity was observed, particularly in head kidney after 4 days of treatment of fish with copper. The two products may induce separately an acute, short and local inflammatory acute phase response by stimulating some components of the innate immune response of healthy fish. The mixture seems to reduce the impact of the each product due to the physical and chemical properties of chitosan to complex with copper. The responses of humoral immune factors of treated carp was modulated by the presence of the parasite, as shown by the high elevation of lysozyme activity observed in parasitised carps after exposition to copper and by increases in natural antibodies levels observed in parasitised carp treated with the copper-chitosan mixture. This could indicate an additive effect on the stress response mediated by parasite. It occurred a greater stress response in the parasitised group than healthy group exposed to the same treatment evoking an additive effect. So, it is important to specify the health status of organisms to understand responses of immunological markers in fish.     

Difference in sensitivity of the mu and kappa systems in cafeteria rats

A highly palatable diet (cafeteria diet) provokes an hyperphagia. The effects of Mu and Kappa opiate antagonists (Mu : Naltrexone 0.5 mg/Kg IP; Kappa Mr2266 0.5; 2.5; 10) and agonists (Mu Morphine 0.05; 0.1; 0.5; 2.5; Kappa Mr2033 0.5; 2.5) were studied on the nocturnal food intake of cafeteria rats and chow rats fed with monotonous food. At low doses Mu as well as Kappa antagonists do not modify the food intake of chow rats, but suppress the hyperphagia induced by the cafeteria diet. Kappa agonist provokes a decrease in food intake in chow and cafeteria rats while the Mu agonist at low doses suppresses the hyperphagia induced by cafeteria diet. The involvement of these two opioid systems in this type of hyperphagia is discussed.     

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.     

Time-course, magnitude and nature of the changes induced in HDL by moderate alcohol intake in young non-drinking males

The effects of moderate alcohol intake on the lipoprotein profile were evaluated in 10 normolipemic abstinent male subjects aged 18-21 years. The experimental period lasted 4 weeks during which 30 g of alcohol were ingested daily as red table wine. It was preceded and followed by 3 weeks of total abstinence. Lipoproteins were analyzed by gradient ultracentrifugation at the end of each abstinence period and weekly during the experimental period, to follow the time-course of alteration. Total HDL were increased by 25% (range 14-72%) during the first 2 weeks of alcohol, lighter HDL3, but not HDL2, exhibiting a greater response than other classes. The effect of alcohol regressed with time and by the 4th week mean HDL levels were only 14% higher than prior to treatment. HDL levels returned to normal on weaning. The wide variations in individual responses were consistent over the experimental period and are suggestive of differences in individual susceptibility.     

Effects of a chronic administration of two benzodiazepines on food intake in rats given a highly palatable diet

Chronic administration of benzodiazepines is known to increase food intake in numerous species. But this effect has been studied only after a unique daily injection and over a short part of the 24 hr cycle. In the present study, during 28 days, drugs were administered to rats receiving ordinary chow or a highly palatable diet (cafeteria diet): diazepam (DZ) (2.5 mg/kg IP) twice a day, or brotizolam (BR) (1 mg/kg IP), a longer acting compound, once a day. In the chow fed rats, DZ and BR provoked a post injection hyperphagia throughout the study, followed by a compensatory hypophagia resulting in 24 hr food intakes not different from those of controls; conversely neither body weight nor weight of fat pads were increased. The cafeteria diet provoked hyperphagia and overweight. DZ did not induce any supplementary hyperphagia. BR provoked a post injection hyperphagia, also compensated in time, resulting again in 24 hr food intakes, body weight gains and weight of fat pads not increased compared to those of cafeteria controls. Thus in the rat, benzodiazepine treatment increases food intake, but only acutely, and does not provoke any trend toward obesity.     

Lindane increases macrophage-activating factor production and intracellular calcium in rainbow trout (Oncorhynchus mykiss) leukocytes

The authors studied the in vitro effects of lindane on macrophage-activating factor (MAF) production by peripheral blood leukocytes (PBLs) in rainbow trout. MAF production by PBLs induced normally by mitogens concanavalin A (ConA) and phorbol myristate acetate (PMA) was not modified by a pretreatment with lindane (from 2.5 to 50 microM). Only a concentration of 100 microM lindane decreased MAF production, associated with cellular death. Moreover, MAF activities were detected in supernatants of PBL cultures treated with lindane from 2.5 to 10 microM in absence of ConA/PMA stimulation. Factors present in these supernatants remain to be identified. Lindane, at concentrations which did not induce MAF production (50 and 100 microM) led to an increase in PBL calcium levels by acting on the endoplasmic reticulum calcium stores. Although the intracytosolic calcium concentration ([Ca(2+)](i)) increase seems to be associated with cell death, lindane-induced MAF production may be linked with other intracellular mechanisms.     

In vivo and in vitro modulation of carp (Cyprinus carpio L.) phagocyte oxidative burst activity by gallium

Since gallium is a metal ion used in semiconductor industry, the toxicological effects were previously evaluated in mammals but the ecotoxicological impacts remain unknown. In term of ecotoxicological risk assessment, the median lethal concentration (LC50 for 96 h of gallium to carp (Cyprinus carpio L.) and the oxidative response of carp phagocytes after the fish were exposed to sublethal levels of gallium were determined. The LC50 of gallium on C. carpio at 96 h was estimated as 96.25 +/- 14.3 mg/L. To determine the effect in vivo of gallium on the phagocyte response, fish were exposed for 96 h to 5 or 50 mg Ga(3+)/L. Carp maintained for 48 or 96 h in water containing 50 mg/L gallium had a significant fall in phagocyte oxidative burst activity in comparison with controls, as well as decreased leukocyte number in blood and increased cytotoxicity. To determine the effect in vitro of gallium on the phagocyte response, isolated phagocytes were exposed for 5 or 15 min to 50 nM, 500 nM, or 5, 50, 100, or 200 microM of Ga(3+). The oxidative burst was increased after in vitro incubation of phagocytes with 50 or 500 nM gallium for 15 min or with 500 nM gallium for 5 min. Moreover, for 50, 100, or 200 microM gallium, the oxidative burst activity of carp phagocytes was significantly decreased. Results indicate that the lethal toxicity of gallium for carp of gallium is not as high as for other metal ions. However, gallium was immunosuppressive for carp at the highest concentrations used (from 50 microM) in vivo and in vitro. At low concentrations, it could be an immunostimulant as observed in vitro.