Abstract
A novel preparation technique, so called "Paste Mold, " was devised for organ and tissue distribution studies. This is the most powerful by joining with autoradioluminography (ARLG), which was established and validated recently in the working group of Forum '93 of Japanese Society for study of xenobiotics. A small piece (10-50 mg) of each organ or tissue was available for measuring its radioactive concentration and it was sampled from the remains of frozen carcass used for macroautoradiography (MARG). The solubilization of the frozen pieces was performed with mixing a suitable volume of gelatine and strong alkaline solution prior to mild heating kept at 40°C for a few hours. After that, the tissue paste was molded in template pattern to form the small plates. The molded plates were contacted with Imaging plate (IP) for recording their radioactive concentration. The recorded IP was processed by BAS2000. The molded plate was formed in thickness of 200 μm, so called infinit thickness against soft β rays, and therefore the resulting relative intensities, represented by (PSL-BG)/S values, indicated practically responsible ratio of the radioactive concentration in organs and tissues, without any calibulation for β-self absorption coefficiency. On the other hand, the left half body of the frozen carcass was used for making whole body autoradiography (WBA) before the Paste-Mold preparation. Comparison was performed for difference in (PSL-BG)/S values of organs and tissues between frozen and dried sections. A good concordance in relative intensities, (PSL-BG)/S by the Paste-Mold preparation was given with those by the frozen sections rather than dried sections. The combination of the Paste-Mold preparation prior to ARLG and WBA method must be the most powerful to give a quantitative and reliable data in the tissue distribution study.
