Discovery of New Isotope

The new isotope ^{241}U was synthesized and systematic atomic mass measurements of nineteen neutron-rich Pa-Pu isotopes were performed in the multinucleon transfer reactions of the ^{238}U+^{198}Pt system at the KISS facility. The present experimental results demonstrate the crucial role of the multinucleon transfer reactions for accessing unexplored neutron-rich actinide isotopes toward the N=152 shell gap in this region of nuclides.

Study of the N=32 and N=34 Shell Gap for Ti and V by the First High-Precision Multireflection Time-of-Flight Mass Measurements at BigRIPS-SLOWRI.

The atomic masses of ^{55}Sc, ^{56,58}Ti, and ^{56-59}V have been determined using the high-precision multireflection time-of-flight technique. The radioisotopes have been produced at RIKEN's Radioactive Isotope Beam Factory (RIBF) and delivered to the novel designed gas cell and multireflection system, which has been recently commissioned downstream of the ZeroDegree spectrometer following the BigRIPS separator. For ^{56,58}Ti and ^{56-59}V, the mass uncertainties have been reduced down to the order of 10 keV, shedding new light on the N=34 shell effect in Ti and V isotopes by the first high-precision mass measurements of the critical species ^{58}Ti and ^{59}V. With the new precision achieved, we reveal the nonexistence of the N=34 empirical two-neutron shell gaps for Ti and V, and the enhanced energy gap above the occupied νp_{3/2} orbit is identified as a feature unique to Ca. We perform new Monte Carlo shell model calculations including the νd_{5/2} and νg_{9/2} orbits and compare the results with conventional shell model calculations, which exclude the νg_{9/2} and the νd_{5/2} orbits. The comparison indicates that the shell gap reduction in Ti is related to a partial occupation of the higher orbitals for the outer two valence neutrons at N=34.

Properties of

Mass-separated ^{187}Ta_{114} in a high-spin isomeric state has been produced for the first time by multinucleon transfer reactions, employing an argon gas-stopping cell and laser ionization. Internal γ rays revealed a T_{1/2}=7.3±0.9 s isomer at 1778±1 keV, which decays through a rotational band with perturbations associated with the approach to a prolate-oblate shape transition. Model calculations show less influence from triaxiality compared to heavier elements in the same mass region. The isomer-decay reduced E2 hindrance factor f_{ν}=27±1 supports the interpretation that axial symmetry is approximately conserved.

First Direct Mass Measurements of Nuclides around Z=100 with a Multireflection Time-of-Flight Mass Spectrograph.

The masses of ^{246}Es, ^{251}Fm, and the transfermium nuclei ^{249-252}Md and ^{254}No, produced by hot- and cold-fusion reactions, in the vicinity of the deformed N=152 neutron shell closure, have been directly measured using a multireflection time-of-flight mass spectrograph. The masses of ^{246}Es and ^{249,250,252}Md were measured for the first time. Using the masses of ^{249,250}Md as anchor points for α decay chains, the masses of heavier nuclei, up to ^{261}Bh and ^{266}Mt, were determined. These new masses were compared with theoretical global mass models and demonstrated to be in good agreement with macroscopic-microscopic models in this region. The empirical shell gap parameter δ_{2n} derived from three isotopic masses was updated with the new masses and corroborates the existence of the deformed N=152 neutron shell closure for Md and Lr.

Pathway for the Production of Neutron-Rich Isotopes around the N=126 Shell Closure.

Absolute cross sections for isotopically identified products formed in multinucleon transfer in the (136)Xe+(198)Pt system at ∼8 MeV/nucleon are reported. The isotopic distributions obtained using a large acceptance spectrometer demonstrated the production of the "hard-to-reach" neutron-rich isotopes for Z<78 around the N=126 shell closure far from stability. The main contribution to the formation of these exotic nuclei is shown to arise in collisions with a small kinetic energy dissipation. The present experimental finding corroborates for the first time recent predictions that multinucleon transfer reactions would be the optimum method to populate and characterize neutron-rich isotopes around N=126 which are crucial for understanding both astrophysically relevant processes and the evolution of "magic" numbers far from stability.

Enhanced ability of regulatory T cells in chronic hepatitis C patients with persistently normal alanine aminotransferase levels than those with active hepatitis.

In hepatitis C virus (HCV) infection, the Th1-type immune response is involved in liver injury. A predominance of immunosuppressive regulatory T cells (Treg) is hypothesized in patients with persistently normal alanine aminotransferase (PNALT). Our aim was to clarify the role of Treg in the pathogenesis of PNALT. Fifteen chronically HCV-infected patients with PNALT, 21 with elevated ALT (CH) and 19 healthy subjects (HS) were enrolled. We determined naturally-occurring Treg (N-Treg) as CD4+CD25high+FOXP3+ T cells. The expression of FOXP3 and CTLA4 in CD4+CD25high+ cells was quantified by real-time reverse transcriptase-polymerase chain reaction. Bulk or CD25-depleted CD4+ T cells cultured with HCV-NS5 loaded dendritic cells were assayed for their proliferation and cytokine release. We examined CD127-CD25-FOXP3+ cells as distinct subsets other than CD25+ N-Treg. The frequencies of N-Treg in patients were significantly higher than those in HS. The FOXP3 and CTLA4 transcripts were higher in PNALT than those in CH. The depletion of CD25+ cells enhanced HCV-specific T cell responses, showing that co-existing CD25+ cells are suppressive. Such inhibitory capacity was more potent in PNALT. The frequency of CD4+CD127-CD25-FOXP3+ cells was higher in CH than those in PNALT. Treg are more abundant in HCV-infected patients, and their suppressor ability is more potent in patients with PNALT than in those with active hepatitis.

Efficient two-color two-step laser ionization schemes of λ1∼ 250 nm and λ2 = 307.9 nm for heavy refractory elements-Measurements of ionization cross-sections and hyperfine spectra of tantalum and tungsten.

We demonstrated efficient two-color two-step laser ionization schemes in the combined use of λ1 ∼ 250 nm and λ2 = 307.9 nm, which are applicable to heavy refractory elements with an atomic number in the wide range of Z = 69-78. We investigated newly observed ionization schemes of tantalum and tungsten atoms in an argon-gas-cell-based laser ion source for the efficient ionization of atoms of unstable nuclei through the two-color two-step laser resonance ionization technique. We experimentally determined the ionization cross sections from the measured saturation curves by solving the rate equations for the ground, intermediate, and ionization continuum populations. Hyperfine structures of these elements were also studied to deduce the isotope-shift, pressure-shift, and pressure-broadening in the resonance spectra of the excitation transitions in the argon gas cell. The electronic factor F255 of the excitation transition λ1 = 255.2115 nm between the ground and intermediate states was deduced from the measured isotope shifts of stable 182,183,184,186W isotopes. The ionization schemes investigated here are applicable to extract any isotopes of these elements by considering the measured pressure shift and nuclear isotope shift in optimizing the wavelength λ1.

KEKCB electron cyclotron resonance charge breeder at TRIAC.

The KEKCB is an electron cyclotron resonance (ECR) ion source for converting singly charged ions to multicharged ones at Tokai Radioactive Ion Accelerator Complex. By using the KEKCB, singly charged gaseous and nongaseous ions were converted to multicharged ones of A/q approximately 7 with efficiencies of 7% and 2%, respectively. The conversion efficiency was found to be independent of the lifetime of the radioactive nuclei having lifetimes of the order of one second. Three collimators located at the entrance and the exit of the KEKCB defined the beam axis and facilitated beam injection. Grinding and washing the surfaces of aluminum electrode and plasma chamber dramatically reduced impurities originating from the ECR plasma of the KEKCB.

Sensory mechanism of oxygen sensor FixL from Rhizobium meliloti: crystallographic, mutagenesis and resonance Raman spectroscopic studies.

FixL of Rhizobium meliloti (RmFixL) is a sensor histidine kinase of the two-component system, which regulates the expression of the genes related to nitrogen fixation in the root nodule in response to the O(2) levels. The crystal structure of the sensor domain of FixL (RmFixLH), which contains a heme (Fe-porphyrin) as a sensing site, was determined at 1.4 A resolution. Based on the structural and spectroscopic analyses, we propose the O(2) sensing mechanism that differs from the case proposed in BjFixLH as follows; conformational changes in the F/G loop, which are induced by steric repulsion between the bent-bound O(2) and the Ile209 side-chain, would be transmitted to the histidine kinase domain. Interaction between the iron-bound O(2) and Ile209 was also observed in the resonance Raman spectra of RmFixLH as evidenced by the fact that the Fe-O(2) and Fe-CN stretching frequencies were shifted from 575 to 570 cm(-1) (Fe-O(2)), and 504 to 499 cm(-1), respectively, as the result of the replacement of Ile209 with an Ala residue. In the I209A mutant of RmFixL, the O(2) sensing activity was destroyed, thus confirming our proposed mechanism.

Efficient lentiviral transduction of human cord blood CD34(+) cells followed by their expansion and differentiation into dendritic cells.

OBJECTIVE: To support immune reconstitution after cord blood transplantation, immunotherapy using gene-modified dendritic cells (DCs), the most potent antigen-presenting cells, can be a powerful strategy for preventing infection and recurrence. To investigate the applicability of lentiviral vector-transduced DCs compared to retroviral vectors, we transduced umbilical cord blood (CB) CD34(+) cells, then expanded and differentiated them into DCs. MATERIALS AND METHODS: We transduced CB CD34(+) cells by vesicular stomatitis virus G-protein pseudotyped self-inactivating lentiviral vector or retroviral vectors carrying the enhanced green fluorescent protein gene. The cells were expanded in the stroma-dependent culture system and transferred to the culture condition for developing DCs. The efficiency of transduction and expression of the transgene in severe combined immunodeficiency (SCID) mice-repopulating cells (SRCs) and DCs were compared between lentiviral vector and retroviral vectors. Induced DCs were cocultured with allogeneic or autologous T cells to test the ability to present antigens. RESULTS: CB CD34(+) cells transduced by lentiviral vector and expanded ex vivo sustained stable transgene expression and multipotentiality by assessing SRCs assay and clonogenic assay of bone marrow cells from the transplanted mice. DCs derived from these cells expressed green fluorescent protein and surface markers CD1a, CD80, and HLA-DR and showed potent allo-stimulatory activity as well as nontransduced DCs did. On the other hand, we did not detect transgene expression in SRCs and DCs transduced by retroviral vectors. CONCLUSION: Gene-modified DCs derived from ex vivo expanded CB CD34(+) cells transduced by lentiviral vector will be useful in future immunotherapy protocols.

Safety management of nuclear medicine personnel with visualisation of air dose rate.

Many people are anxious about radiation exposure for the reason that radiation cannot be seen. With the aim of devising a way for medical personnel to perform their medical duties without worry about radiation exposure, we attempted safety management using a system that displays the air dose of radiation in real time. Measurements were made in a lung ventilation scintigraphy examination room with the use of Xe-133. An SCI-type RI detector from Hamamatsu Photonics, which displays the air dose rate in real time, was used for the measurements. These radiation measurements were continued from the start to finish of the examination. The measurements were made in two locations, on the patient inhalation tube side and on the opposite side. Measurements were made on the patient tube side in 24 tests and on the opposite side in 12 tests. The maximum air dose rate was 3.7 ± 2.1 µSv/h on the patient tube side and 1.1 ± 0.5 µSv/h on the opposite side. Thus, the level on the opposite side was about 1/5 that of the tube side. To accurately perform lung ventilation scintigraphy, a medical worker needs to observe the patient's breathing status up close. Because of this, some medical workers are worried about radiation exposure during tests. The simplest way to reduce exposure would be to maintain a distance from the examination tube that is the source of radiation. The measurements in this study were made to encourage medical workers' recognition of this fact. Displaying specific numbers not only serves as basic data for managing staff operations, but is also thought to reassure workers through visualization.

Erythromycin reduces the severity of bronchial hyperresponsiveness in asthma.

It has been demonstrated that bronchial hyperresponsiveness is a characteristic feature of bronchial asthma, and airway inflammation plays an important role in bronchial hyperresponsiveness. Erythromycin is an antibiotic extensively used worldwide which is also reported to have anti-inflammatory action. This study was designed to clarify whether erythromycin could favorably alter bronchial responsiveness in patients with bronchial asthma. To estimate bronchial responsiveness, histamine challenge was performed in 23 patients with bronchial asthma (atopic type, 11; nonatopic type, 12). All patients were treated for ten weeks with erythromycin, 200 mg three times daily, orally. After ten weeks' treatment, PC20, an index of bronchial sensitivity, was increased significantly. There was no difference between atopic and nonatopic patients in the improvement of PC20. It was concluded that erythromycin reduces the severity of bronchial responsiveness in patients with bronchial asthma.

Crystal structure of the unliganded alkaline protease from Pseudomonas aeruginosa IFO3080 and its conformational changes on ligand binding.

The crystal structure of the unliganded alkaline protease from Pseudomonas aeruginosa IFO3080 has been determined at 2.0 A resolution by the X-ray method. The enzyme consists of N-terminal catalytic and C-terminal beta-helix domains. On structural comparison between the present unliganded enzyme and structurally- known liganded enzyme, some structural changes were observed around the active site. In the unliganded enzyme, Y216 serves as the fifth ligand for the active site zinc ion. On ligand binding, Y216 may move to form a hydrogen-bond with the carbonyl oxygen of the P1 residue of a ligand peptide. D191 in the flexible loop, Y190 to D196, over the active site cleft forms hydrogen-bonds with the backbone atoms of the P1 and P2 residues of the ligand to close the entrance to the cleft. The water molecule which is the fourth ligand for the zinc ion is replaced by the carbonyl oxygen of the P1 residue. These structural changes around the active site may reflect the substrate-binding mode during the enzymatic reaction.

Acute lethal injury of lung and liver in mice transplanted with ex vivo-expanded CTLs.

Clinical application of cytotoxic T lymphocytes (CTL) induced in vitro is extensively used for the treatment of viral infection and malignant diseases. We produced anti H-2d CTL in vitro from C57BL/6 (B6) splenocytes presensitized with (B6 x DBA/2) F1 (BDF1) splenocytes to establish a model system of CTL therapy. The specificity and cytotoxic activity were high enough (E/T ratio 1:1 = 38.8%) to induce graft versus host reaction. Though the total number of B6 splenocytes decreased by 0.27 during the 4 days of culture, the number of CD8+ lymphocytes increased 1.3-fold. When more than 5 x 10(6) cells of H-2d-reactive CTL were transplanted into BDF1 mice, mice died within 2 days postinduction. This lethal effect was not seen in the mice induced with ConA-stimulated T cells. Histological examination of the lungs and liver revealed massive infiltration of neutrophils in alveoli and the necrosis of hepatocytes. Therefore, this protocol was shown to be effective to produce alloantigen-specific CTLs and applicable to in vitro manipulation such as retrovirus-mediated gene transfer.

Triglucosylation on the biotransformation of (+)-menthol by cultured cells of Eucalyptus perriniana.

Cultured cells of Eucalyptus perriniana biotransformed (+)-menthol to its gentiobioside and triglucoside [2,6-di-O-(beta-D-glucopyranosyl)-beta-D-glucopyranoside]. The structures of these compounds were determined by means of NMR techniques.

Pulmonary lymphangiomyomatosis (LAM) developing chylothorax.

We describe a case of pulmonary lymphangiomyomatosis (LAM) with chylothorax that developed in a 46-year-old Japanese woman. This patient exhibited clinical symptoms of dyspnea and chest X-ray showed right pleural effusion. Thoracocentesis demonstrated chylous effusion. Chest computed tomography (CT) scan revealed multiple cystic lesions. Subsequent thoracoscopy revealed the chylorrhea from swelled vessels on the diaphragm. The clinical diagnosis, based on histological examinations with biopsy specimens obtained by thoracoscopy, was pulmonary LAM. Although the hormone therapy was not effective, chylous effusion was improved by the pleurodesis. Pulmonary LAM developing chylothorax is rare in Japan.

Churg-Strauss Syndrome with pleural involvement.

A 51-year-old Japanese man with Churg-Strauss Syndrome (CSS) diagnosed by pleural biopsy is described. He was hospitalized because of high fever and bilateral knee, elbow and shoulder joint pain. Chest roentgenogram and chest computed tomography (CT) scan revealed bilateral massive pleural effusion. Pleural biopsy revealed eosinophilic infiltration and necrotizing granulomas. He was treated with oral prednisolone and his symptoms improved. This is the first report of CSS diagnosed by pleural biopsy.

Simultaneous quantitative determination of 3H, 14C, 32P, 35S, 51Cr, and 125I on the surface of a paper disc using combustion.

A paper disc that retained 3H, 14C, 32P, 35S, 51Cr, and 125I on its surface was combusted in a flow-type combustion flask filled with oxygen. The combustion products containing five radionuclides, except 14CO2, were collected by washing the inner wall of the flask with 0.5-M hydrogen peroxide containing excess NaHSO3. The 14CO2 that remained in the gas phase of the flask was introduced into another flask for absorption into an organic base solution. By determining the radioactivity of both the solutions containing the respective radionuclides by means of NaI(Tl) and liquid scintillation counters, the six radionuclides in the solutions were quantified. The detection limit of surface contamination with this method was compared with the limit specified by Japanese law for the surface contamination of controlled areas.

Pretreatment of animal wastes containing radioisotopes with dry-distillation.

Mice that had been radiolabeled with one of seven isotopes by intraperitoneal or subcutaneous administration were dry-distilled at 800 degrees C for 10 min, and the fate of the radionuclide was examined. The radionuclides administered were 3H, 14C, 32P, 35S, 45Ca, 51Cr, and 125I, all of which are commonly used in animal experiments. After dry-distillation, 95% of 3H was found in the distillate (condensate), and 80% and 16% of 14C were recovered from exhaust gas and residual solids, respectively. Only between 10 and 20% of 35S was found in distillate. The remainder of the residual 35S was recovered from the inner wall of the exhaust vent of the dry-distillation equipment. About 24% of 125I was also recovered from the inner wall of this same exhaust vent, and the residual radioactive materials were recovered from the residual solids. On the other hand, 32P, 45Ca, and 51Cr were recovered entirely from the residual solids. The weight of the animals decreased to about 10%, and the volume to about 20% (mice and rats) to 40% (rabbits) after dry-distillation. The residual solids of animal wastes generated by dry-distillation were odorless and chemically and biologically stable. Dry-distillation has many merits as a pretreatment for the disposal of animal wastes containing radioactive material because of the easy handling, storage, and transportation of the residual solids.

[A clinical study on ceftazidime in the treatment of intractable respiratory infections].

Ceftazidime (CAZ) was administered to 51 patients (37 males, 14 females) with respiratory infections including severe cases, accompanied by various underlying respiratory diseases. The clinical efficacy and side effects of CAZ were investigated. The mean age and body weight of these 51 cases were 62.6 years and 48.0 kg, respectively. CAZ was administered by intravenous drip infusion (daily dose of 2-4 g) for a mean of 14.7 days to a mean total dose of 56.7 g. Clinical efficacy rates were 64% (18 of 28 cases), 80% (16 of 20 cases) and 67% (2 of 3 cases) for airway and intermediary regional infections, pneumonia (including lung abscess) and pyothorax, respectively. In the bacteriological study, efficacy rates and bacterial eradication rates were 69% and 67%, 33% and 20%, 100% and 100%, and 100% and 100% for infections caused by Pseudomonas aeruginosa (13 cases), Staphylococcus aureus (6 cases), Streptococcus pneumoniae (6 cases) and Klebsiella pneumoniae (4 cases), respectively, and bacterial eradication was achieved in both of 2 cases of Peptostreptococcus anaerobius and 2 cases of Haemophilus influenzae, and 1 case each of Peptococcus sp., Fusobacterium necrophorum and Serratia marcescens. Side effects observed were eruption in 1 case (2%) and elevated GOT, GPT and Al-P values in 1 case (2%), but these cases tended to recover after CAZ treatment was discontinued.