Long-pulse beam acceleration of MeV-class H(-) ion beams for ITER NB accelerator

In order to realize neutral beam systems in International Thermonuclear Experimental Reactor whose target is to produce a 1 MeV, 200 A/m(2) during 3600 s D(-) ion beam, the electrostatic five-stages negative ion accelerator so-called "MeV accelerator" has been developed at Japan Atomic Energy Agency. To extend pulse length, heat load of the acceleration grids was reduced by controlling the ion beam trajectory. Namely, the beam deflection due to the residual magnetic field of filter magnet was suppressed with the newly developed extractor with a 0.5 mm off-set aperture displacement. The new extractor improved the deflection angle from 6 mrad to 1 mrad, resulting in the reduction of direct interception of negative ions from 23% to 15% of the total acceleration power, respectively. As a result, the pulse length of 130 A/m(2), 881 keV H(-) ion beam has been successfully extended from a previous value of 0.4 s to 8.7 s. This is the first long pulse negative ion beam acceleration over 100 MW/m(2).

Development of negative ion extractor in the high-power and long-pulse negative ion source for fusion application

High power and long-pulse negative ion extractor, which is composed of the plasma grid (PG) and the extraction grid (EXG), is newly developed toward the neutral beam injector for heating and current drive of future fusion machines such as ITER, JT-60 Super Advanced and DEMO reactor. The PG is designed to enhance surface production of negative ions efficiently by applying the chamfered aperture. The efficiency of the negative ion production for the discharge power increased by a factor of 1.3 against that of the conventional PG. The EXG is also designed with the thermal analysis to upgrade the cooling capability for the long pulse operation of >1000 s required in ITER. Though the magnetic field for electron suppression is reduced to 0.75 of that in the conventional EXG due to this upgrade, it was experimentally confirmed that the extracted electron current can be suppressed to the allowable level for the long pulse operation. These results show that newly developed extractor has the high potential for the long pulse extraction of the negative ions.

A possible mechanism of the nucleus accumbens and ventral pallidum 5-HT1B receptors underlying the antidepressant action of ketamine: a PET study with macaques

Ketamine is a unique anesthetic reagent known to produce various psychotic symptoms. Ketamine has recently been reported to elicit a long-lasting antidepressant effect in patients with major depression. Although recent studies provide insight into the molecular mechanisms of the effects of ketamine, the antidepressant mechanism has not been fully elucidated. To understand the involvement of the brain serotonergic system in the actions of ketamine, we performed a positron emission tomography (PET) study on non-human primates. Four rhesus monkeys underwent PET studies with two serotonin (5-HT)-related PET radioligands, [(11)C]AZ10419369 and [(11)C]DASB, which are highly selective for the 5-HT1B receptor and serotonin transporter (SERT), respectively. Voxel-based analysis using standardized brain images revealed that ketamine administration significantly increased 5-HT1B receptor binding in the nucleus accumbens and ventral pallidum, whereas it significantly reduced SERT binding in these brain regions. Fenfluramine, a 5-HT releaser, significantly decreased 5-HT1B receptor binding, but no additional effect was observed when it was administered with ketamine. Furthermore, pretreatment with 2,3-dihydroxy-6-nitro-7-sulfamoylbenzo(f)quinoxaline (NBQX), a potent antagonist of the glutamate α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor, blocked the action of ketamine on the 5-HT1B receptor but not SERT binding. This indicates the involvement of AMPA receptor activation in ketamine-induced alterations of 5-HT1B receptor binding. Because NBQX is known to block the antidepressant effect of ketamine in rodents, alterations in the serotonergic neurotransmission, particularly upregulation of postsynaptic 5-HT1B receptors in the nucleus accumbens and ventral pallidum may be critically involved in the antidepressant action of ketamine.

A small compound targeting TACC3 revealed its different spatiotemporal contributions for spindle assembly in cancer cells

The mitotic spindle is assembled by the coordinated action of centrosomes and kinetochore microtubules. An evolutionally conserved protein family, transforming acidic coiled-coil (TACC), has been shown to be involved in this process. In humans, TACC3 is aberrantly expressed in a variety of human cancers, but its biological significance remains to be elucidated. Here, using a novel compound targeting TACC3, spindlactone (SPL), we show that the perturbation of TACC3 selectively inhibited the nucleation of centrosome microtubules in ovarian cancer cells. In contrast to centrosome microtubules, the kinetochore microtubules were robustly assembled, forming ectopic spindle poles that resulted in multipolar spindles. Interestingly, the extensive inhibition of TACC3 partially suppressed the nucleation of kinetochore microtubules. These dose-dependent effects of SPL were consistent with the results observed by the depletion of TACC3 and its binding partner, colonic and hepatic tumor overexpressed gene protein (TOGp). Although these proteins both have roles in the assembly of centrosome and kinetochore microtubules, their contributions were spatiotemporally different. Notably, SPL did not affect spindle assembly in normal cells. Furthermore, the oral administration of SPL significantly suppressed tumor growth in vivo. The unique mechanism of action of SPL not only enables it to be used as a tool to dissect the molecular basis of spindle assembly but also to provide a rationale for the use of TACC3 as a molecular target for cancer treatment. This rationale offers an opportunity to develop new strategies for cancer chemotherapy that overcome the limitations of microtubule toxins and expand their scope and clinical efficacy.

Vaccination against seasonal influenza is effective in Japanese patients with rheumatoid arthritis enrolled in a large observational cohort

OBJECTIVE

To investigate the effectiveness of influenza vaccination in patients with rheumatoid arthritis (RA) from a large practice-based cohort.

METHOD

Patients with RA enrolled in the Institute of Rheumatology, Rheumatoid Arthritis (IORRA) cohort completed self-administered questionnaires as part of the April IORRA surveys of 2001, 2002, 2003, and 2007, which included their influenza vaccination status and occurrence of an actual influenza attack. Vaccine coverage rate and attack rates were calculated in each season. Relative risks (RRs) of vaccination for an actual influenza attack were evaluated and risk factors for influenza infection were determined by multiple logistic regression analysis.

RESULTS

Data from 3529, 4518, 4816, and 4872 patients in the 2000/01, 2001/02, 2002/03, and 2006/07 seasons, respectively, were analysed. Coverage rates were increased from 12.2% in the 2000/01 season to 38.7% in the 2006/07 season. For each season, the attack rates in vaccinated patients trended lower than the rates in unvaccinated patients but the differences were not significant; however, by combining these four seasonal results, the attack rate was significantly lower for vaccinated patients [RR 0.83, 95% confidence interval (CI) 0.71-0.95, p < 0.01]. Male gender [odds ratio (OR) 1.48, 95% CI 1.25-1.76, p < 0.001] was associated with increased risk whereas vaccination was associated with reduced risk for influenza attack (OR 0.76, 95% CI 0.63-0.91, p < 0.01). There were no associations between influenza attacks and RA disease activity, treatment with methotrexate (MTX) or corticosteroids.

CONCLUSION

Influenza vaccination was effective in patients with RA regardless of disease activity or treatment.