Extraction behavior of rutherfordium into tributylphosphate from hydrochloric acid

The extraction behavior of rutherfordium (Rf) into tributylphosphate (TBP) from hydrochloric acid (HCl) has been studied together with those of the lighter group-4 elements Zr and Hf. The extractability of261Rf,169Hf, and85Zr into TBP was investigated under identical conditions in 7.2–8.0 M HCl by on-line reversed-phase extraction chromatography. The percent extractions of Rf, Hf, and Zr into the TBP resin increase steeply with increasing HCl concentration, and the order of extraction is Zr > Hf ≈ Rf. By considering the order of chloride complexation among these elements, it is suggested that the stability of the TBP complex of Rf tetrachloride is lower than those of Zr and Hf.

Intercomparison study on (152)Eu gamma ray and (36)Cl AMS measurements for development of the new Hiroshima-Nagasaki Atomic Bomb Dosimetry System 2002 (DS02)

In the process of developing a new dosimetry system for atomic bomb survivors in Hiroshima and Nagasaki (DS02), an intercomparison study between (152)Eu and (36)Cl measurements was proposed, to reconcile the discrepancy previously observed in the Hiroshima data between measurements and calculations of thermal neutron activation products. Nine granite samples, exposed to the atomic-bomb radiation in Hiroshima within 1,200 m of the hypocenter, as well as mixed standard solutions containing known amounts of europium and chlorine that were neutron-activated by a (252)Cf source, were used for the intercomparison. Gamma-ray spectrometry for (152)Eu was carried out with ultra low-background Ge detectors at the Ogoya Underground Laboratory, Kanazawa University, while three laboratories participated in the (36)Cl measurement using accelerator mass spectrometry (AMS): The Technical University of Munich, Germany, the Lawrence Livermore National Laboratory, USA and the University of Tsukuba, Japan. Measured values for the mixed standard solutions showed good agreement among the participant laboratories. They also agreed well with activation calculations, using the neutron fluences monitored during the (252)Cf irradiation, and the corresponding activation cross-sections taken from the JENDL-3.3 library. The measured-to-calculated ratios obtained were 1.02 for (152)Eu and 0.91-1.02 for (36)Cl, respectively. Similarly, the results of the granite intercomparison indicated good agreement with the DS02 calculation for these samples. An average measured-to-calculated ratio of 0.98 was obtained for all granite intercomparison measurements. The so-called neutron discrepancy that was previously observed and that which included increasing measured-to-calculated ratios for thermal neutron activation products for increasing distances beyond 1,000 m from the hypocenter was not seen in the results of the intercomparison study. The previously claimed discrepancy could be explained by insufficient understanding of the measured data.

Experimental identification of spin-parities and single-particle configurations in 257No and its alpha-decay daughter 253Fm

alpha-gamma and alpha-electron coincidence spectroscopy for a short-lived heavy actinide nucleus (257)No (T(1/2) = 24.5 s) has been performed using a gas-jet transport system and an on-line isotope separator. Spin-parities of excited states in (253)Fm fed by the alpha decay of (257)No have been identified on the basis of the measured internal conversion coefficients. The nu3/2(+)[622] configuration has been assigned to the ground state of (257)No as well as to the 124.1 keV level in (253)Fm. It was found that the ground-state configuration of (257)No is different from that of lighter N = 155 isotones.

Direct preparation of radioactive fullerenes as a tracer for applications

The C60 and C70 fullerenes were irradiated by high-energy gamma-rays and charged particles. The irradiated samples were dissolved in CS2 and/or toluene and filtered to remove insoluble by-products. Finally, radioactive fullerenes and products labeled with 11C or 13N were isolated and detected in the liquid phase by radiochromatography. It was found that (1) not only 11C or 13N radioactive monomer fullerenes but also their dimers (trimers and, possibly, tetramers) were produced by recoil implantation process following nuclear reaction and (2) the radioactive fullerene labeled with 11C yields has led to high yields.

Proposed standard for human blood vitamin B1 value using HPLC. The Committee for Vitamin Laboratory Standards, Japan

Standard reference ranges for all laboratory test values are mandatory. This study was designed to establish a reference range for blood vitamin B1 levels, since the normal range has not been determined in the Japanese population. We founded the Japan Committee for Vitamin Laboratory Standards, which was incorporated with the Vitamin Society of Japan and the Japanese Society of Nutrition and Food Science. We standardized whole blood vitamin B1 levels using three HPLC techniques (post-column reverse-phase HPLC, pre-column reverse-phase HPLC, and precolumn GP-HPLC). The reference range was obtained in 54 volunteers administered a 1,800 kcal diet with 2 mg of vitamin B1 (1.74 mg measured) daily to avoid marginal vitamin B1 deficiency in the population. The range for each assay was 26-47, 28-51, and 28-56 ng/ml, respectively. Our data suggest that 26-28 ng/ml is the lower limit of normal for whole blood vitamin B1, but further studies in a larger population are needed in order to obtain more definitive results.

Intake ratio of water-insoluble dietary fiber to the water-soluble one in Japanese: an estimation on dietary records and the secular consideration on the national nutrition survey

Thirty-four foods were analyzed in order to determine the content of water-soluble dietary fiber (SDF) and insoluble dietary fiber (IDF). Using the results with the standard table for 227 foods, the intake ratio of IDF/SDF of an average Japanese was calculated for the period 1946-1990. The ratio was 3.22 in 1990 as calculated on the food intakes shown in the national nutrition survey, and the secular change was not detected since 1946 when the ratio was 3.30. The ratio was also shown to be well preserved between types of households including the age of the head. Using dietary records of 60 healthy city workers (average 42.8 years) for 4 weeks, however, the weekly average ratio for an individual was found to vary in the range of 2.25-5.13 although the total average for 60 individuals was 3.33. Thus, the well preserved IDF/SDF intake ratio for an average Japanese showed, on the contrary, a wide variation of food selection between each person.

Cloning and sequencing of the chaperonin-encoding Cctd gene from Fugu rubripes rubripes

CCT, a chaperonin containing t-complex polypeptide 1 (TCP-1), is a cytosolic molecular chaperone involved in the folding of proteins. We have isolated the Cctd gene from a Fugu rubripes rubripes (Frr) genomic library using a rat Ccta cDNA as a probe, and cloned its cDNA by reverse transcription-polymerase chain reaction (RT-PCR) using a pair of oligodeoxyribonucleotides corresponding to the 5' and 3' non-coding regions of Frr Cctd. Cctd spans a region of 4.7 kb and consists of at least 13 exons with small introns of about 144 bp on average. The Cctd cDNA sequence revealed a deduced polypeptide of 536 amino acids sharing a high degree of homology with that of the mouse Cctd cDNA (88%). Cctd is present as a single-copy gene, as shown by genomic Southern blot analysis, and can be used for evolutionary and classification analyses of Fugu species.

In vivo biological behavior of a water-miscible fullerene: 14C labeling, absorption, distribution, excretion and acute toxicity

BACKGROUND

Water-soluble fullerenes have recently been shown to exhibit considerable in vitro biological activity including cytotoxicity, site-selective DNA cleavage and inhibition of HIV protease. To assess the potential of these compounds as drugs, studies on the in vivo behavior of fullerenes are needed. We therefore set out to synthesize a radiolabeled, water-soluble fullerene, in order to obtain data on the oral absorption, distribution and excretion of this class of compounds.

RESULTS

We synthesized a 14C-labeled water-soluble [60]fullerene using dipolar trimethylenemethane, which undergoes cycloaddition to [60]fullerene. When administered orally to rats, this compound was not efficiently absorbed and was excreted primarily in the feces. When injected intravenously, however, it was distributed rapidly to various tissues, and most of the material was retained in the body after one week. The compound was also able to penetrate the blood-brain barrier. Acute toxicity of the water-miscible fullerene was found to be quite low.

CONCLUSIONS

Although the water-soluble fullerenes (and possibly their simple metabolites) are not acutely toxic, they are retained in the body for long periods, raising concerns about chronic toxic effects. The fact that fullerenes distribute rapidly to many tissues suggests that they may eventually be useful to deliver highly polar drugs through membranes to a target tissue, however, and they may even have applications in the delivery of drugs to the brain. Recent advances in fullerene synthetic chemistry may also make it possible to control fullerene absorption/excretion profiles in the future.

Immunomodulating activity of thymosin fraction 5 and thymosin alpha 1 in immunosuppressed mice

We found that both thymosin from calf thymus and its constituent peptide alpha 1 prepared by chemical synthesis restore cell-mediated immunity following its suppression in mice by injection of 5-FU. Conditions suitable for assessing the thymosin activity by means of footpad reaction were established in such immunosuppressed mice. In this new animal model, thymosin alpha 1-peptide showed activity at a low dose of 5-50 micrograms/kg, which was 100-1,000 times less than that required for thymosin F-5 preparations. Further studies utilizing the adoptive transfer technique showed that alpha 1-peptide corrects the 5-FU-induced suppression of mature T cells, transferring the DTH response as well as that of macrophage function responsible for the expression of footpad reaction. Furthermore, regeneration of lymph node and bone marrow cells as well as CFU-c (progenitor cells of macrophages and granulocytes) was enhanced by thymosin alpha 1 in the 5-FU-treated mice. All these results indicate that thymosin alpha 1 accelerates the replenishment and maturation of haematopoietic cells, including not only T cells but also macrophages, when they have been severely damaged by the 5-FU treatment.

Comparative studies on the immunosuppressive effect among 5'-deoxy-5-fluorouridine, ftorafur, and 5-fluorouracil

The immunosuppressive effect of 5'-deoxy-5-fluorouridine (5'-DFUR, Ro 21-9738) was examined for both humoral and cell-mediated immunity in mice in comparison with that of 5-fluorouracil and Ftorafur (FT-207). By both oral and intraperitoneal administration, 5'-DFUR was found to be much less suppressive than 5-fluorouracil and FT-207 in all immune responses tested; hemolysin plaque-forming cells, serum hemolysin titer, delayed-type hypersensitivity and allogeneic tumor rejection. Furthermore, 5'-DFUR did not induce any reduction in either the spleen weight, thymus weight, total spleen cell number, or peripheral leucocyte number.