Preparation of ethylenediaminephosphoramidates of nucleotides and derivatization with fluorescein isothiocyanate.

Fluorescence post-labeling of nucleotides is a potentially useful technique for the detection of trace amounts of damaged DNA (DNA adducts). Towards this goal, we have studied a derivatization procedure starting with the four major 5'-deoxynucleotides as model compounds. The 5'-phosphate group was first labeled with ethylenediamine via a phosphorimidazolide intermediate in methanol with an organic-soluble carbodiimide. The resulting ethylenediaminephosphoramidate products were reacted in turn with fluorescein isothiocyanate. The reaction sequence has been characterised at all stages by high-performance liquid chromatography.

Influence of some anti-inflammatory drugs on the activity of aryl hydrocarbon hydroxylase and the cytochrome P450 content.

The metabolism of benzo[a]pyrene is mediated by the mixed function oxidase system including the cytochrome P450-dependent aryl hydrocarbon hydroxylase. The data of the present study revealed the ability of various commonly used anti-inflammatory drugs to alter the activity of this enzyme system, where all the tested drugs, namely phenyl butazone, ketoprofen, piroxicam, and acetaminophen, caused an increase in both the activity of aryl hydrocarbon hydroxylase and the cytochrome P450 content whether administered as a single dose or as a repeated dose for 6 consecutive days. The percentage of change for all drugs except phenyl butazone was proportional to the duration of drug administration. On the other hand, pyrazole which is chemically related to phenyl butazone, had no significant effect when administered as a single dose but caused a decrease in both studied parameters when administered as a repeated dose for 6 consecutive days. The mechanisms by which these commonly used drugs modify the aryl hydrocarbon hydroxylase activity and the cytochrome p450 content are discussed in the text.