0000000000285039
AUTHOR
K. Urich
Accumulation and discharge behavior of Cs-137 by zebra fish (Brachydanio rerio) in different aquatic environments
The uptake and release kinetics of137Cs from water by the tropical fishBrachydanio rerio has been studied under controlled laboratory condition. The accumulation of this radionuclide from food was avoided by feeding the fishes separately in an inactive environment. A steep inverse dependence of bioconcentration factor (BCF) with potassium concentration has been observed. This can formally be described by the equation BCF=5.2 · [K+]−0.44. The elimination rate constant K in fresh water conditions has been found to have a magnitude of 0.014±0.03 d−1 which corresponds to a biological half-life of 51±10 days. The uptake and release kinetics ofBrachydanio rerio has been compared with earlier stud…
Action of the racemate and the isomers of the platelet-activating factor antagonist bepafant (WEB 2170) after oral administration to guinea-pigs and rats
The aim of the present study was to clarify whether there is a difference in terms of potency and pharmacodynamic half time between the isomers and the racemate of the platelet-activating factor antagonist WEB 2170 (bepafant) after oral administration to guineapigs or rats. The following experiments were performed in the guinea-pig. Infusion of platelet-activating factor at 30 ng/ (kg × min) for 30 min to anaesthetized guinea-pigs induced a decrease of respiratory flow and mean arterial blood pressure. Oral pretreatment with WEB 2170 or isomers, respectively, 60 min before infusion of plateletactivating factor inhibited these changes in a dose-dependent manner. The ED50S for inhibition of r…
Pharmacological characterisation of a new model of antigen-induced pulmonary late-phase reaction in the conscious guinea pig which uses additional polymyxin B inhalation
The aim of the present study was to develop a new model of allergic late-phase reaction in the airways of conscious guinea pigs (GPs) and to characterise it by pharmacological intervention. GPs were pretreated with cyclophosphamide and sensitized with ovalbumin (OA) in Al(OH)3. Weekly inhalations of polymyxin B were performed before and during sensitization and continued throughout the study period. Under cover of 10 mg/kg i.p. mepyramine all GPs still exhibited a pronounced immediate reaction (IR), peaking during the first 15 min after OA. Nine out of 15 GPs demonstrated, during screening, a reproducible (twice) second phase (late phase reaction (LPR)] of decreased airflow and tidal volume…
Quinol sulphate, a new conjugate of phenol in goldfish.
1. Metabolism of phenol in goldfish yielded the known phenyl conjugates in fish--phenyl sulphate and phenyl glucuronide. Additionally, quinol sulphate, a new conjugate of phenol in fish, was detected.
Uptake and release kinetics of134Cs by Goldfish (Carassius auratus) and137Cs by Zebra Fish (Brachydanio rerio) in controlled aquatic environment
The uptake and release kinetics of134Cs by Goldfish (Carassius auratus) and137Cs by Zebra Fish (Brachydanio rerio) from aquatic media of different ionic compositions and temperature was studied in controlled laboratory conditions. The accumulation of radiocesium in the case ofBrachydanio rerio is observed to be strongly dependent on the potassium ion concentration of the aquatic medium, but in the case ofCarassius auratus this dependence is quite weak. The biological half-lives of the cesium isotopes incorporated into the fish investigated in the present work vary from 19 to 80 days and are influenced by the temperature and the ionic composition of the aquatic medium.