| Research Abstract |
Boron neutron capture therapy (BNCT) is a following therapy. After accumulation of ィイD110ィエD1B in cancer tissues and then neutrons are irradiated, and using produced neutron fission energy cancer parts are destroyed. BNCT was applied to the malignant melanoma using p-Boronophenylalanine (BPA), and good results have been obtained. In order to increase the effects, a further ィイD110ィエD1B accumulation is expected. For such a purpose, it is important that after clarification of the accumulation mechanism, and based on the results, new compounds with tumor accumulation property are synthesized. In this purpose of the study it is important to develop compounds with more strong selective property by the investigation the relation between melanoma-related materials and BPA using ィイD111ィエD1B-NMR and elucidation the ィイD110ィエD1B accumulation property. JEOL LA400 NB of Shinshu University was used. The ィイD111ィエD1B concentration in the sample was very low, then a large numbers of accumulation was req
… More
uired. As a result, the obtained spectra has large curved background, and it is impossible to detect the peak of complex which is due to the relation between the melanin related materials and BPA. In 1998, we have tried to improve the curved background by subtracting the signal of the water containing solution from that of the samples. Using this method. The interaction was investigated between the melanoma-related materials which was taken out melanoma-bearing hamsters and BPA. As a result, the ィイD111ィエD1B-NMR peak of BPA decreases with time, and that of boric acid, which is considered to be formed -after BPA interacted with melanoma-related materials, increases. This is indirect confirmation of the interaction between BPA and melanoma-related materials. In 1999, we have synthesized BPA-tyrosine dipeptide. Tyrosine is a melanin precursor. In melanoma, melanin synthesis is accentuated, and uptake of tyrosine increases. Therefore, BPA-tyrosine dipeptide is expected to be much more incorporated into melanoma than BPA. Since BPA and tyrosine are amino acid and both can exist either L-form or D-form, then we have tried to synthesize four optical isomers, L-BPA-L-tyrosine, L-BPA-D-tyrosine, D-BPA-L-tyrosine, and D-BPA-D-tyrosine. Less
|
