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Although rare, malignant transformation of intracranial epithelial cysts has a poor prognosis and surgery followed by radiotherapy seems to be the best therapeutic modality.

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SummaryIntra-arterial metabolic radiotherapy (using lipiodol labelled with iodine-131 or rhenium-188) is a therapeutic approach that can be used for the treatment of hepatocellular carcinomas (HCC). We propose a detailed description of the tumoral model using the N1-S1 cell line as well as a technique for intra-arterial injection of radiolabelled lipiodol in order to undertake preclinical studies necessary for the evaluation of a new molecule. We also report the principal technical pitfalls that were faced. The speed of injection of the tumoral cells is a key factor in the tumoral induction since slow injections lead to a tumoral induction rate of 36.3% compared with 76.6% (Po0.01) when using very slow injections. This parameter should thus be controlled carefully during the subcapsular injection of the tumoral cells. In addition, when injecting radiolabelled lipiodol, anaesthesia should not be performed with isoflurane since this leads to a reduction in tumoral uptake. Indeed, we found a 'tumour/ healthy liver' uptake ratio of only 2.170.7 with isoflurane as against 4.472.6 (Po0.05) when anaesthesia was carried out by intraperitoneal injection of ketamine. Lastly, we show that the tumour size has an influence on the tumoral uptake of radiolabelled lipiodol; therefore, this parameter must also be carefully controlled.

The electrochemical behavior of MnO2 electrodes during cathodic reduction in buffered medium ( 1MKOH ) was studied on the basis of diffusion of protons into the solid phase according to Coleman's theory. The kinetics of the process was followed by means of a diffusion equation which predicts the general form of the discharge satisfactorily during potentiostatic and galvanostatic reductions. A method for determining the product of the active surface area of the electrode by the square root of the diffusion coefficient of protons in the crystal lattice is given and results are compared for various samples of MnO2 .