The heart of Daphnia magna: effects of four cardioactive drugs.

We used Daphnia magna bioassays to determine the LC(50) and the effects on the heart of the cardioactive drugs ouabain, verapamil, metaproterenol and metoprolol. Distinctions were made between the pharmacological and toxicological effects of these drugs and the adequacy of physicochemical characteristics of its habitat (reconstituted water). Video microscopy and digital image processing were used to study the pharmacological effects on the heart.

Determination of wastewater LC50 of the different process stages of the textile industry.

Textile plants are very important sources of toxic discharges. The purpose of the research described in this paper was to use bioassays with daphnids to determine the LC50 values of textile wastewater samples taken from different stages of the finishing textile industry. Toxicity due to dyeing, chlorination, and the absence of adequate physicochemical conditions for daphnid survival were considered.

Lead concentration in different compartments of the bovine eye.

It is known that lead is a metabolic substitute of calcium and recently, in vitro results showed that glycosaminoglycans and proteins are capable of binding lead. Therefore, in this work, the level of lead in aqueous humor, vitreous humor, lens and sclera of bovine eyes was analyzed in order to establish a relationship between lead concentration and the contents of glycosaminoglycans, proteins, water and calcium in those structures. Lead was determined by means of atomic absorption spectrometry after acid digestion.

In vitro lead cation-hyaluronic acid interaction.

It is the purpose of this investigation to study the in vitro spontaneous interaction lead-hyaluronic acid using the equilibrium dialysis technique. The following working conditions were used: membrane retention capacity starting from 12000 D; solvent was an aqueous buffer solution (pH 7.4); relation of internal-external volume of 0.

Determination of polynuclear aromatic hydrocarbons present in asphaltenes from Mexican oil. A possible environmental risk.

A supercritical fluid extraction and HPLC analysis of the asphaltenes derived from Mexican oil was performed. The aim was to identify potentially mutagenic polynuclear aromatic hydrocarbons present in asphaltenes, since roof waterproofing applications in this country present a significant exposure to hot asphaltene vapors that might conceivably carry such toxic hydrocarbons and therefore pose a health hazard to the workers who apply molten asphaltenes.