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This study was conducted to evaluate the pharmacokinetics of flumequine following intraperitoneal administration of 14 C-Flumequine (12 mg/kg, 100 μCi/kg) in sea bream ( Sparus auratus ). Three fish (147 ± 29 g) were collected at various time points ranging from 0.5 h to 144 h post administration. Absorption, distribution and elimination were studied using whole body autoradiography and liquid scintillation counting whereupon the concentration of flumequine equivalent versus time was evaluated in major organs and tissues (liver, bile, heart, brain, blood, kidney, intestine, spleen, red and white muscle). An agreement between the data obtained from whole body autoradiography and liquid scintillation counting was observed. A rapid and extensive distribution of flumequine to the major organs 0.5 h after dosing was recorded. The main route of elimination appeared to be biliary excretion due to the high concentration of radioactivity in the bile and the prolonged elimination phase compared to others tissues. The elimination of flumequine from the blood followed a two compartmental model with half life of the first phase and second phase being 0.98 h and 21.4 h respectively. The maximum flumequine recorded in blood (C max ) was 9.09 mg/kg at 0.78 h (T max ). Only traces of drugs were observed in the major tissues of the fish 72 h after administration. Based on the current results and the elimination in edible tissues in particular, flumequine seems to be an excellent treatment candidate for sea bream. [ABSTRACT FROM AUTHOR]

In mussel Mytilus galloprovincialis tissues, metallothionein belongs to two different gene classes, mt10 and mt20, showing differential expression at both basal conditions and under heavy metal challenge. In this study, a new more highly sensitive technique, expression analysis of mt10 and mt20 mRNA levels by quantitative reverse transcription polymerase chain reaction, was used to assess the effects of heavy metal contamination in the digestive glands of mussels caged along the Tunisian coast. To validate the new assay, total metallothionein protein, amount of heavy metals (zinc, copper, cadmium), and a biomarker of oxidative stress such as malondialdehyde content, were assessed in the same tissues. At the investigated sites, the molecular assay showed variations of mt20 relative gene expression levels within one or two orders of magnitude, with maximum values at two sites severely polluted with cadmium, Mahres (100-fold) and Menzel Jemile (165-fold). Changes in mt10 expression were recorded at all sites where copper had significantly accumulated, although fold induction levels were less pronounced than those of mt20. In this paper, gene expression data are discussed in relation to the studied biomarkers, demonstrating that the molecular technique based on the differential expression of mt10 and mt20 genes represents (i) a useful and robust tool for studying and monitoring heavy metal pollution under field conditions, and (ii) an improvement in the application of metallothionein as a biomarker of response to exposure to heavy metals in marine mussels. [ABSTRACT FROM AUTHOR]

Over the past decade, molecular, biochemical and cellular markers have been extensively used in pollution monitoring of aquatic environments. Biochemical markers have been selected among early molecular events occurring in the toxicological mechanisms of main contaminants. This paper assesses the marine environment quality along the Tunisian coasts using a statistical approach. Clams ( Ruditapes decussatus ) were collected during the four seasons of 2003 on seven different sites from the Tunisian coasts. Oxidative stress was evaluated in gills using catalase activity (Cat), neutral lipids and malonedialdehyde accumulation. Glutathione S- transferase activity is related to the conjugation of organic compounds and was evaluated in both, gills and digestive glands. Acetylcholinesterase activity was evaluated as the biomarker of exposure to organophosphorous, carbamate pesticides and heavy metals. For each biomarker, a discriminatory factor was calculated and a response index allocated. For each site, a global response index was calculated as the sum of the response index of each biomarker. Discriminant analysis shows significant differences between sites and seasons compared with control sample. Faroua (site 1) and Menzel Jemile (site 2) seem to be the less polluted with respect to the other sites for all seasons. Gargour (site 6) shows the highest Multimarker Pollution Index during the four seasons, indicating higher contamination level. [ABSTRACT FROM AUTHOR]