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Application of «Radioluminography (RLG)» using ultra sensitive radiodetector, IP, for analysis of blood 14 C-concentration was investigated. This method gave us high quallity RLG images and accurate blood concentration directly from the images. It was shown that RLG is useful for simple and rapid quantitative analysis of radioactivity concentration in liquid such as blood and plasma

Intestinal absorption and tissue distribution of water-soluble lignins which had both immunomodulating and antiviral activities were investigated using the isotope tracer techniques. Three types of water-soluble lignins with different molecular weights, i.e., EP3 (av. mol. wt., 3.2 × 105D) and SB1000 (mol. wt., 103—104D), both of which were fractionated from LEM (an extract of culture medium of Lentinus edodes mycelia), and PLS(purified lignosulfonate, av. mol. wt., 2 × 104D) were used after being labeled with 14C-HCHO.After p. o. administration, every [14C] lignin was absorbed and reached maximum levels in the tissues, especially, kidney cortex, lymph node, liver and vertebra within 6 hr. 14C-EP3, the sample of the highest molecular weight, showed the lowest absorption, whereas it remained in cortex for a longer period. By summing up the isotope amount in urine and tissues, the absorption extents of 14C-EP3, 14C-PLS and 14C-SB1000 were estimated to be approximately 0.8%, 5.9% and 8.0% of radioactivity, respectively. Absorption and prolonged remain of 14C-EP3 in the lymph node and vertebra suggest that the in vitro immunological activities of this lignin would be linked to those in vivo.

Conventional whole-body autoradiography (MAR) shows detailed tissue distribution of radioisotopes “relatively”, not “quantitative”. We attempted to establish quantitative analytical method for MAR (QMAR) using computer-assisted densitometry system introduced from Dr. Sokoloff's laboratories, N.I.H. and Imaging-plate system developed by Fuji Photo Film Co., Ltd. Autoradiograms were prepared from rats after administration of (CH3-14C) FO-1561 (S-adenosylmethionine sulfate tosylate, SAMe) and exposed on X-ray films (Kodak, SB-5) for 3.5 days or Imaging-plates for 1.5 hrs with 14C-staircases. Measurement of isotope concentration was done from the autoradiograms by comparing optical densities or detection intensities of the regions of interest with a series of standards. Concentrations of SAMe-14C in blood, muscle, thymus, submaxillary gland and brain obtained from QMAR methods were comparable to those obtained from conventional tissue dissection method (LSC). Correlation coefficient between QMAR and LSC method was lager than 0.9. In addition, quantitative information was obtained on the distribution in such small organs which can not be dissected or on the localization of radioactivity in organ or tissue.