(+) -9-Amino-4-demethoxy-9-deoxy-7-O- (2-deoxy-β-D-erythro-pentopyranosyl) daunomycinone (1a) was labeled with carbon-14 for use in mammalian metabolic studies. The synthesis was achieved according to the scheme illustrated in Fig. 3. Friedel-Crafts acylation of [carbonyl-14C] phthaloyl chloride (2) with the optically active bicyclic amidoketone (3) gave the tetracycline amidoketone (4) . Protection of the C13-carbonyl group of 4 with neopentylglycol furnished the ketal (5) . Treatment of 5 with 1, 3-dibromo-5, 5-dimethylhydantoin under illumination produced the oxazine (6) . Hydrolysis of the oxazine ring of 6 under acidic condition and subsequent deketalization afforded the aminoketone (8) . Glycosidation of 8 with acetyl 2-deoxy-3, 4-di-O-acetyl-D-erythro-pentopyranose in the presence of trimethylsilyl trifluoromethanesulfonate (TMSOTf) provided the acetylated glycoside (10) . Alkaline hydrolysis of 10 with potassium bicarbonate gave la. The overall yield was 12.4% from 2.
Accumulation and excretion of137Cs in goldfish, Carassius auratus auratus, from radioactive diets (killifish, Oryzias latipes, meats accumulated137Cs in the radioactive freshwater) or control diets (killifish meats mixed137CsCl) were investigated in order to elucidate the accumulation mechanism of the radionuclide in natural living fishes. The accumulation of137Cs, expressed in concentration ratio, in whole body of the fish showed a increasing tendency in proportion to the rearing time. On the other hand, the excretion of137Cs, expressed in retention rate, in whole body rearing by administration of non-radioactive commertial diets after the accumulation above for 7 days, demonstrated a rapid decreasing at first few days, and followed a gradual decreasing tendency (the biological half lives were about 1.5 days and 52 days, respectively) . As for the tissues and organs, higher accumulation and higher excretion were found in the viscera than those in the muscle. It is so suggested that the metabolic turnover rate of this radionuclide for the viscera is more rapid than that for the muscle. From the experimental results, it was confirmed that the relative contribution by ingestion of the radioactive diets in the accumulation of137Cs in natural environmental fish was comparatively higher in comparison with uptake of the radionuclide in the radioactive freshwater. With regard to the difference between the radioactive diets and the control diets, the accumulation of137Cs in whole body of the fish from the radioactive diets was less than that from the control diets to rearing 5 days, but afterward was not different. The difference of the accumulation between these diets will be attributable to that of the metabolic turnover between these diets.
The simultaneous acquisition method in SPECT has some advantages, such as potentially doubling throughput in an examination and halving the acquisition time. However, interradionuclide scattering limits diagnostic accuracy. We evaluated99mTc and201Tl scattering using three energy windows. These windows were set at 71 keV with 15% window width for201Tl images, at 90 keV with 10% window width for scatter images, and at 140 keV with 15% window width for99mTc images. From phantom studies, the scatter correction coefficient, a, was measured to be 1.07, while the crosstalk correction coefficient, β, was measured to be 0.14. The corrected counts, a, in the 71 keV window for201Tl image and the corrected counts, b, in the 140 keV window for99mTc image were given as follows : a =A-αC, b =B-βa, where A is the raw counts in the 71 keV window, B the raw counts in the 140 keV window, and C the raw counts in the 90 keV window. Simultaneous dual-radionuclide99mTc/201Tl scintigraphy is feasible using99mTc scatter and201Tl crosstalk correction coefficients.