Design of iodinated radioligands for SPECT imaging of central human 5-HTR using a ligand lipophilicity efficiency approach.

A series of iodinated ligands for the SPECT imaging of 5-HT receptors was designed starting from the previously reported hit MR-26132. We focused on the modulation of the piperidine-containing lateral chain by introducing hydrophilic groups in order to decrease the liphophilicity of the new ligands. All the synthesized compounds were tested for their binding affinities on 5-HTRs and based on the Ligand Lipophilicity Efficiency approach, compound 13 was further selected for radioiodination with iodine-125 and imaging experiments.

Lichens as indicators of tritium and radiocarbon contamination.

Lichens were collected in France in the surroundings of a military nuclear facility in Burgundy, near the la Hague reprocessing plant and in an area away from any direct source of contamination. Organically bound tritium (OBT) has been analysed on 18 samples and radiocarbon on 11. It appeared that on the most contaminated spots, the OBT activity in lichens was higher than the background by a factor of 1000 and was still a factor 10-100 at a distance of 20 km from the source.