Poor bioavailability of oxytetracycline in sharpsnout sea bream Diplodus puntazzo

The pharmacokinetics of oxytetracycline (OTC) were investigated following single intravascular injection (40 mg/kg) in sharpsnout sea bream (90 g) at 19 degreesC. The distribution half-life (t(1/2alpha)) and the elimination half-life (t(1/2beta)) of OTC were calculated to be 1.4 and 35 h, respectively. The apparent volume of distribution of the drug at steady-state (V-d(ss)) was found to be 41/kg. The total clearance rate (CLT) of the drug was low (0.08 1/kg h). Repeated attempts to investigate the bioavailability of OTC following oral administration (75 mg/kg; forced-fed or via the feed), revealed undetectable levels of the drug in plasma and muscle samples. Poor tissue absorption is likely due to significant hepatic metabolism of OTC in sharpsnout sea bream, but this requires further investigation. Thus, oral administration of OTC in fanned sharpsnout sea bream should be discouraged in favour of other routes of administration or other antibiotic drugs. (C) 2003 Elsevier B.V. All rights reserved

Bioaccumulation of polychlorinated biphenyls (PCBs) and dichlorodiphenylethane (DDE) methyl sulfones in tissues of seal and dolphin morbillivirus epizootic victims

Polychlorinated biphenyl (PCB) and dichlorodiphenylethane (DDE) methyl sulfone (MSF) metabolites possess high affinities for binding two homologous 16,000 Da homodimeric receptor proteins in the lung (Clara cell secretory protein, CCSP) and the uterus (uteroglobin, UG), leading to selective bioaccumulation of MSFs in these tissues. As marine mammals are highly exposed to organochlorines, concentrations of PCBs, PCB MSFs, DDT, and DDE MSF were analyzed in blubber, lung, and uterus samples from harbor seal (Phoca vitulina) and striped dolphin (Stenella coeruleoalba) morbillivirus epizootic victims to investigate uterine and lung MSF accumulation. Mean uterus concentrations of PCB MSFs and DDE MSF in harbor seals were 0.61 and 0.04 microg/g lipid weight and in striped dolphins 0.05 and 0.01 microg/g lipid weight. Mean lung concentrations of PCB MSFs and DDE MSF in harbor seals were 0.96 and 0.02 microg/g lipid weight and in striped dolphins 0.16 and 0.01 microg/g lipid weight. To ascertain whether uterine and lung bioaccumulation of MSFs is possible due to the presence of CCSP and UG in seals, CCSP and UG proteins in uterine flushings and in uterine and lung and epithelial tissue from Baltic gray and ringed seals were characterized using gel electrophoresis and Western blotting techniques. UG- and CCSP-like proteins with molecular weights of 16,000 Da were resolved in all samples. This is the first demonstration of this protein in any marine mammalian species. The toxicological implications of MSF binding with UG and CCSP in marine mammals are discussed

Local Hölder continuity of weak solutions for an anisotropic elliptic equation

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