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Abstract: Radioactive multitracer technique was applied to study the screening of in vivo interrelations between radioactive tracers (46Sc, 59Fe, 58Co, 65Zn, 75Se, 83Rb, 85Sr and 88Zr) and stable Mn species. Comparative uptake rates were examined in the blood, 9 organs (thymus, lung, cardiac muscle, spleen, pancreas, kidney, liver, testes and bone) and 8 brain regions (cerebral cortex, striatum, hippocampus, thalamus and hypothalamus, midbrain, cerebellum, pons and medulla, olfactory bulb) using the 3-weeks-old mice fed the Mn-deficient, -adequate or -excessive diets with Mn concentration from 0.4 to 300.4 ppm. Significant diet-related differences were found for 65Zn uptake in some organs. The dietary Mn-deficient state induced increase Zn absorption in thymus and lung in short-time span (during 48 hours after injection). On the other hand, no significant diet-related differences were observed in any brain regional uptake rates except for 54Mn uptake rate. The screening results are expected to give us new findings concerning the diet-related element-element interrelations in living bodies.

Radioactive multitracer technique was applied to study the brain regional uptake of trace elements by the normal mice during aging. The brain regional radioactivities of 46Sc, 54Mn, 65Zn, 75Se, 83Rb and 88Zr were measured 48 hours after intraperitoneal injection of a solution in normal mice aged 6 to 52 weeks to evaluate the brain regional (corpus striatum, cerebellum, cerebral cortex, hippocampus, and pons and medulla) uptakes. The radioactive distributions of 46Sc, 54Mn and 88Zr tracers were variable and region-specific in the brain, while those of 65Zn, 75Se and 83Rb tracers were comparable among all regions of interest. The brain regional uptakes of all tracers slightly increased with age from 10 to 28 weeks, and then remained constant during aging after 28 weeks. These uptake variations may be involved in the functional degenerative process of the blood-brain barrier during aging.

Brain regional cerebral concentrations of minor and trace elements, Na, Mg, Cl, K, Mn, Zn, Rb and Br were determined in young and aged mice, by instrumental neutron activation analysis for small amounts of regional (corpus striatum, cerebellum, cerebral cortex, hippocampus, midbrain, pons and medulla olfactory bulb) samples. Significant age-related differences were found for Mn concentration in all brain regions: The Mn concentration of the young brain was higher than those of aged brain, in addition, Zn was distributed heterogeneously, and highly concentrated in cerebral cortex and hippocampus regions in both young and aged mice. These results suggest that, in the aged brain, Mn is required less than in the young brain, on the other hand, Zn is required equally in both young and aged brains.

Abstract: The radioactive multitracer technique was applied to a study on the uptake of trace elements in normal C57BL/6N mice. Comparative uptake behavior of46Sc,54Mn,59Fe,58Co,65Se,83Rb and88Zr tracers was examined among 11 organs (brain, cardiac muscle, lung, liver, spleen, pancreas, kidneys, bone, muscle, eyeballs and testes) and blood, and evaluated in terms of the “tissue uptake rate (the radioactivity percentage of injected dose per gram of tissue, %dose/g)”. The multitracer technique revealed reliable data demonstrating characteristic uptake of the 8 trace elements, Sc, Mn, Fe, Co, Zn, Se, Rb and Zr by the brain and other organs, as well as the distinctive features of the accumulation and retention of each element in the brain.

Abstract: A radioactive implant induced X-ray emission (RIXE) technique was examined for the in vivo determination of heavy elements. By the use of67Ga,99mTc,123I,123Xe and201Tl implant excitation sources, the excitation efficiency and X-ray attenuation were measured to reveal the potential pairs of source-heavy element of interest for in vivo elemental analysis by the RIXE technique. Detection limits for the RIXE in vivo analysis were evaluated according to Currie's criterion. Four pairs,99mTc–Pb,201Tl–I,133Xe–Cd and123I–Cd are potential.

Abstract: Carrier-free99mTcO4– eluated from clinical99Mo/99mTc generators was examined to determine its specific activity. The observed specific activity was found to be always lower than the calculated value based on the99Mo–99mTc–99Tc decay scheme data. These results could be explained in terms of existence of excess Tc loaded onto generator column.

Abstract: Preparation of lanthanide fluoride and chloride films has been studied by chemical vapor deposition (CVD) using Ln(thd)3 (Ln=lanthanide(III); thd=2,2,6,6-tetramethyl-3,5-heptanedionato ligand) and Y(thd)3 with gas mixture systems of CF2Cl2 (difluorodichloromethane)/O2 and CF2Cl2/H2. Two kinds of fluorides, LnOF oxyfluoride and LnF3 triffluoride, were obtained separately along a CVD tube at atmospheric pressure and temperature as low as 300–600°C by the reaction of Ln(thd)3 chelates with CF2Cl2/O2 gas system. The chemical characteristics of the CVD products were considered from the thermochemical point of view.

Abstract: Reversed-phase high-performance liquid chromatography with u.v. detection was applied for rapid and sensitive determination of pertechnetate in99Mo/99mTc generator eluates, using a mixture solvent of acetonitrile and 0.04M aqueous acetate buffer (1/1) containing a few volume percentage of 0.5 M tetra-n-butylammonium hydroxide as the mobile phase. Employing a mgr-bondapak C13 column, the TcO 4– species was separated, monitored with absorbance at 254 nm, and observed at the retention time of 3.5 min. The detection limit was found to be 5.2·10–10 g of Tc for each injection. Total Tc contents in the99mTc eluates from clinically-used99Mo/99mTc generator were analyzed by this technique. The99mTc (99Tc) species was separated from the contaminant99Mo. This method was found to be useful for the purification of99mTc (99Tc) as well as the determination of total Tc content.

Abstract: Preparation of thin films of lanthanide (Ln) sulfides has been studied by the chemical vapor deposition (CVD) method, using metal beta-diketonato chelates with 2,2,6,6-tetramethyl-3,5-heptanedione and reactant H2S gas as starting materials. Two kinds of sulfides, Ln2O2S oxysulfides and EuS monosulfide, were obtained as thin films at temperatures as low as 390–570 °C. The CVD method was confirmed to be suited for the above purpose.

Abstract: Preparation of thin film deposits of lanthanide, thorium and uranium oxides has been studied by chemical vapor deposition (CVD) method using beta-diketonate metal chelates with 2,2,6,6-tetramethyl-3,5-heptanedione and some reactant gases as starting materials. The deposition process was carried out using a special apparatus designed for the CVD method at atmospheric pressure and temperatures as low as 400–600°C.As a result, it was demonstrated that each chelate used was well suited for the above purpose by its high volatility and reactivity with the reactant, especially with water vapor.

Abstract: Radioactive implant induced X-ray emission (RIXE) spectrometry was examined by mixing a sample in solution with a radioisotope. The radioisotopes of57Co,67Ga,75Se,99mTc,111In,125I and201Tl were used as implant X-ray excitation sources. Copper, strontium, iodine, barium, lead and uranium solutions were used as samples to be analyzed. K X-ray for all samples and L X-rays for lead and uranium samples were measured with a pure Ge detector. The excitation characteristics of each radioisotope are discussed using the effective excitation efficiency (eegreff) defined by the equation eegreff=Nc/(NaNd), where Nc is the number of counts in the X-ray peaks, Na is the number of atoms of interest in the sample, and Nd is the total number of decays of radioisotope for the counting interval.