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  • Author or Editor: M. Akaboshi x
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Abstract  

Various rare earth elements (REEs) in standard samples supplied by the IAEA namely mussel (IAEA-142) and lichen (IAEA-336) were examined by ICP-MS and INAA. For ICP-MS, 200 mg each of the samples were dissolved in conc. nitric acid using a microwave sample-preparation system. After repeated concentration-dilution procedures (final volume; 10–20 ml), 1 ml of the sample was supplied for assay. La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb could be detected in the order of magnitude of 10−3 ng/g. Activation analysis carried out using 300 mg of the sample powders failed to detect REEs except La, Ce, Sm and Eu because of a strong interference due mainly to24Na and32P induced in the samples by irradiation. The REE patterns (NASC-normalized) obtained for both the organisms are of the same in their shapes except for all the values for sea animal mussel which are somewhat higher than those for land plant lichen. However, we found a large difference in the other elements contents between the two organisms. For example, Na, Cl, Mg, K, and Ca contents in mussel are about 26, 7, 4.5, 3.5, and 2 times, those in lichen. As the concentrations in the sea water for these elements is from 102 (K and Ca) to 103 (Na, Cl and Mg) order of magnitude higher than in the land water, the result seems reasonable to assume that the higher the concentration of the element around the organisms the higher its content in the organisms.

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Abstract  

Several rare earth elements (REEs) and other elements in algae were investigated by ICP-MS and INAA. Algae materials were supplied from an IAEA Intercomparison Study:Chlorella vulg. grown under reduced levels of toxic elements (IAEA-391) and IAEA-393 algae was grown in a medium to which certain toxic elements were added. 34–691 mg of algae samples were dissolved in conc, nitric acid using a microwave sampleppreparation system. REEs could be detected in the order of magnitude of 10−3 ng/g by ICP-MS. Activation analysis failed to detect any REEs because of a strong interference due mainly to24Na and32P. The distriubtion patterns of these REEs in algae slightly differed from those ofCarya sp. and tobacco leaves, and differed significantly from that of fern leaves. The distribution pattern was rather similar to that found in the North American shale composite (NASC).

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Abstract  

The literature indicates that the interaction of Tb3+ with DNA modified by the antitumour drug cis-diaminedichloroplatinum(II) (CDDP) results in substantial enhancement of the fluorescence of this cation, while no enhancement is observed in the case of DNA modified by irradiation with ionizing radiation. This study investigates the effect of Tb3+ on the survival of cultured mammalian cells treated with CDDP. HeLa cells were treated with a combination of195mPt-CDDP and TbCl3, and the relationship between lethal effect and the numbers of Tb and/or Pt atoms binding to DNA, RNA and proteins was examined. The Tb content in each fraction was determined using instrumental neutron activation analysis. It was found that the cytotoxic effect of CDDP was greatly enhanced by the presence of Tb ions (D0 of CDDP fell from 8.3 μM without Tb to 3.2 μM with 0.75 mM Tb), while no such effect was found in radiation-induced cell-killing. The number of Tb atoms bound to DNA molecules in a cell was calculated to be about 4.5·107, namely 1 per 1.400 nucleotides, under that situation.

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Abstract  

The lanthanides (REEs) in 142 fern leaves collected from 9 sampling sites in Japan were analyzed by instrumental neutron activation analysis. Between two REEs a strong positive correlation was found in the logarithmic scattering diagram with correlation and regression coefficients close to unity, suggesting neither selective accumulation by plants nor different availability from soil between the two elements. However, between Tb and the other REEs the relationship showed two lines with the same correlation coefficient. This suggested that there must be a difference in the availability of REEs or in their absorption characteristics by plants. Further analysis revealed that the splitting was due to some difference in the environmental factors where the fern grew. However, the amount of REE in the soil collected together with the corresponding fern did not reflect the REE concentration in the fern leaves.

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Abstract  

We have investigated the concentrations of REEs in fern leaves collected indifferently to the fern species from 9 sampling sites in Japan using INAA. The results indicated a large variation in the values obtained between fern leaves. In the present investigation we applied the same analytical method on the samples (Blechnaceae, a kind of fern, mature and developing leaves were collected from the same plant) restrictively gathered from the University Forests in Ashiu, Kyoto University. It was demonstrated that the variations in the REE concentrations decreased by one to two order of magnitude, and that the REE contents in developing leaves were also one to two orders of magnitude lower than those in mature leaves. It can be considered that fern accumulates REEs with their growth stages.

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Abstract  

The effect of hyperthermia on the cell killing efficiency of Pt atoms binding to DNA, RNA and protein molecules of HeLa cells treated withcis-diamine(1,1-cyclobutanedicarboxylato)platinum(II) (CBDCA) was examined. HeLa S-3 cells were treated with195mPt-radiolabeled CBDCA for 60 minutes at various temperatures, and the relationship between the lethal effect and the number of Pt atoms binding to DNA, RNA and proteins was examined. The mean lethal concentration (D0) of carboplatin for a 60 min-treatment at 0, 25, 37, 40, 42 and 44°C was 671.2, 201.5, 67.3, 33.4, 20.2 and 15.6 μM, respectively. By using identically treated cells, the number of Pt-atoms combined with DNA, RNA and protein molecules were determined in the subcellular fractions. Thus, the D0's given as the drug concentrations were replaced with the number of Pt-atoms combined in each fraction. Then, the cell-killing efficiency of the Pt atom was expressed as the reciprocal of the number of Pt-atoms combined and was calculated for each molecule. The efficiency for DNA molecules was 0.699, 1.42, 2.65, 4.84, 7.74 and 8.28·104 nucleotides, respectively, for the conditions described above. From 0 to 44°C, the cell-killing efficiency of Pt atoms increased by a factor of 11.9.

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Abstract  

The lanthanides (REE) in 142 fern leaves collected from several sampling sites in Japan have been determined by neutron activation analysis, and the correlations between any two REEs in the logarithmic scattering diagram were examined. The relationship was expressed by the general formula, Y=aX+b with a correlation coefficient R. A strong positive correlation was seen between any two REEs in the diagram with a regression coefficient and a correlation coefficient close to unity. However, between Eu or Tb and other REEs the relationship was split into two lines with the same correlation coefficient. From the intercept b, the relative abundance of the two elements was determined for each REE and compared with those in hickory and tobacco leaves. These findings indicated that the abundance pattern of fern leaves is quite different from those of hickory and tobacco leaves. Namely, the relative abundance of La and Ce was quite similar in the three plants, but the abundance of the other REEs (Nd, Sm, Gd, Dy and Lu) was considerably lower in ferns than in hickory and tobacco leaves. For Eu and Tb the higher values obtained in fern leaves coincided with those of the two plants.

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Abstract  

An experimental method is described for the synthesis of195mPt-radiolabeled cis-diammine (glycolato) platinum (II) (254-S). Ten mg of 95% enriched194Pt was irradiated for 75 h in the hydraulic conveyer of KUR at a thermal neutron flux of ca. 8.15×1013 n·cm–2·s–1, and the195mPt-radiolabeled 254-S was synthesized and purified using HPLC (column: Dichrosorb Diol, elution: 80% CH3CN). The chemical yield was approximately 45%, with chemical purity greater than 98.4%. The radionuclidic purity was nearly 100% and the specific activity, 7.2 MBq·mg–1 254-S.

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Abstract  

An improved method is described for the synthesis of195mPt-radiolabelled cis-diamminedichloroplatinum/II. An amount of 10 mg of 95% enriched194Pt was irradiated for 75 h in the hydraulic conveyer of the KUR at a thermal neutron flux of approximately 8.15×1013 n.cm–2.sec–1 and the195mPt-radiolabelled CDDP was purified using HPLC. The chemical yield is 61% its chemical purity is greater than 99.74% the radiochemical purity is nearly 100%, and the specific activity is 7.4×106 Bq mg–1 CDDP/200 Ci mg–1 CDDP/.

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Abstract  

Content of 40 elements in plant leaves, soils and rocks collected from several sampling sites in Okayama Prefecture was analyzed by instrumental neutron activation analysis using the Research Reactor of Kyoto University. Of these, 16 elements were taken up, and the relationship among their amounts in plants, rocks and soils was discussed, focusing mainly on the essential elements of higher plants and related elements in the periodic table. Although most element contents in plant were different among species, the mediam values of the most non-essential elements in the leaf were lower than the contents in the soil and rock samples. However, essential elements showed significantly higher median values than those in the soil and rock samples. Most element contents in leaves showed a logarithmic normal distribution. The normal distribution was observed in most essential elements except for zinc, while non-essential elements did not show a normal distribution. The results obtained by analysis of variance, showed that the plant species studied could be divided into four major groups, namelyDicotyledoneae, Monocotyledoneae, Gymnospermae andPteridophyta. In general,Dycotyledoneae andPteridophyta had higher element contents thanMonocotyledonaeae andGymnospermae.

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