Patulin is immunosuppressive and there is limited evidence of its carcinogenicity in experimental animals. The International Agency for Research on Cancer (IARC) initiated a programme for the development of degradation techniques for the commonly investigated mycotoxins. As a part of this programme, the following techniques were tested for the degradation of patulin: treatment with ammonia, treatment with ascorbic acid, and treatment with potassium permanganate in acidic or in alkaline conditions. Patulin analysis was performed by using HPLC with UV detection. Mutagenic activity of degradation residues was tested by in Salmonella typhimurium strains TA 97a, TA 98, TA 100, and TA 102. Complete disappearance of patulin was not achieved after 92 h of treatment with ascorbic acid. All the other methods tested led to complete removal of the molecule. However, the technique using potassium permanganate in acidic conditions produced residues which were mutagenic without activation to Salmonella typhimurium strains TA 100 and TA 102, which was attributed later to Mn2+. The two other techniques gave satisfactory results and were selected for further validation studies.

Ammonia↗

PubMedDate not supplied

Flow cytometry to evaluate the parasitemia of Plasmodium falciparum.

The resistance of plasmodiums to the current antimalarial agents has spurred the search for new active molecules of vegetal origin or chemical synthesis. The screening of antimalarial molecules "in vitro" was done by simple but tedious techniques such as quantification of parasitemia through optical microscopy or by using radioactive markers. We have developed a new method to evaluate parasitemia by using the ODAM ATC 3000 flow cytometer and biological cell sorter. We selected the ethidium bromide for labelling the nucleic acids of Plasmodium falciparum, and we optimised the method by using a mathematical model: the design of Hadamar. This simple technique presents the advantage of being an objective and rapid count of large number of red cells (10(6) x 10(7)). This method is rapid, reliable, reproducible, devoid of subjectivity and provides more precise results than those of optical microscopy. The good correlation between paraitemia measured by optical microscopy and fluorescence obtained by flow cytometry allows us to recommend this technic for the screening of new antimalarial molecules.

Ethidium↗