N=2 Supersymmetric Sigma Models and D-branes

We study D-branes of N=2 supersymmetric sigma models. Supersymmetric nonlinear sigma models with 2-dimensional target space have D0,D1,D2-branes, which are realized as A-,B-type supersymmetric boundary conditions on the worldsheet. When we embed the models in the string theory, the Kahler potential is restricted and leads to a 2-dim black hole metric with a dilaton background. The D-branes in this model are susy cycles and consistent with the analysis of conjugacy classes. The generalized metrics with U(n) isometry is proposed and dynamics on them are realized by linear sigma models. We investigate D-branes of the linear sigma models and compare the results with those in the nonlinear sigma models.Comment: 23 pages, 5 figure

Construction of Supergravity Backgrounds with a Dilaton Field

A new class of non-compact Kahler backgrounds accompanied by a non-constant dilaton field is constructed as a supergravity solution. It is interpreted as a complex line bundle over a base manifold comprising of a combination of arbitrary coset spaces, and also includes the case of Calabi-Yau manifolds. The resulting backgrounds have U(1) isometry. We consider N=2 supersymmetric sigma-models on them, and derive a non-Kahlerian solution by U(1) duality transformation, which preserves N=2 supersymmetry.Comment: 13 pages, minor correction

Threonine 138 is crucial for the Quaternary Structure and the Thermostability of Thermus thermophilus Inorganic Pyrophosphatase.

Inorganic pyrophosphatase (EC. 3.6.1.1) from Thermus thermophilus (Tth PPase) forms the thermostable hexamer，and it was suggested from X-ray studies that its intersubunit interactions stabilize the whole molecule. However，the contribution of Thr138 at the intertrimer interface to quatemary structure and thermostability was unknown functionally. Therefore，we prepared four Thr138-substituted variants (T138A，V ，N ，and H) by site-directed mutagenesis. Then，thermostabilities of the enzyme activity and the quatemary structure for T138V and A were decreased relative to those of the wild type Tth PPase，whereas T138H and N variants remained much hexamer contents and the enzyme activity than T138V and A. Therefore，we suggest that the polar group in Thr138 of Tth PPase is more crucial than the methyl group for thermostability and quatemary structure，and it may contribute to the formation of stable trimer-trimer interface

Changes in the quality of diabetes care in Japan between 2007 and 2015: A repeated cross-sectional study using claims data

AimTo assess the temporal changes in the quality indicators pertaining to the process measures of diabetes care during a recent decade in Japan.MethodsA five-fold repeated cross-sectional study was conducted using health insurance claims data provided by the Japan Medical Data Center between April 2006 and March 2016. We identified 46,631 outpatients with antidiabetic medication who regularly visited hospitals or clinics at least every three months. We evaluated the quality indicators pertaining to glycemic control monitoring, lipid profile monitoring, retinopathy screening, nephropathy screening, and appropriate medication choice. The proportions of patients who received appropriate examinations/prescriptions, by observation period and either the type of antidiabetic medication or facility type were estimated using generalized estimating equation (GEE) models with multiple covariate adjustments.ResultsThe quality indicator values for appropriate medication choice and nephropathy screening improved between 2007 and 2015, whereas those for glycemic control monitoring and retinopathy screening remained suboptimal. Patients prescribed medications in larger hospitals were likelier to undergo the recommended examinations (e.g. retinopathy screening: 36.1% (95% CI: 35.4–36.7%) for clinic, 40.6% (95% CI: 39.1–42.2%) for smaller hospital, and 46.0% (95% CI: 44.8–47.2%) for larger hospital in 2015).ConclusionsSeveral process measures of diabetes care remained suboptimal in Japan

Risk Factors for Infection in Patients with Remitted Rheumatic Diseases Treated with Glucocorticoids

It is well known that infection is one of the major causes of morbidity and mortality in rheumatic disease patients treated with high-dose glucocorticoids, especially in the early phase after achievement of disease remission. The aim of this study was to identify the risk factors for infection, with a focus on the dose of glucocorticoids administered, following the achievement of disease remission in rheumatic diseases patients. We retrospectively analyzed the medical records of rheumatic disease patients who had been treated with glucocorticoids. The primary endpoint was the incidence rate of infection during a period from 1 to 2 months after the commencement of treatment. From April 2006 to March 2010, 19 of 92 patients suffered from infection during the observation period. Age≧65 yrs, presence of interstitial pneumonia, diagnosis of systemic vasculitis and serum creatinine level≧2.0mg/dl were found to be univariate predictors for infection. However, only the presence of interstitial pneumonia was an independent risk factor for infection (HR＝4.50, 95%CI＝1.65 to 14.44) by the Cox proportional hazard model. Even after achievement of clinical remission, careful observation is needed for patients with interstitial pneumonia, more so than for those receiving high-dose glucocorticoids

コウネツセイ サイキン Thermus thermophilus ムキ ピロリンサン カスイ ブンカイ コウソ ノ error-prone PCR ヘンイ ドウニュウ ニヨル ネツ ギョウシュウ ヨクセイ

Thermus thermophilus Inorganic pyrophosphatase (E.C. 3.6.1.1., Tth PPase) exhibits high thermostability, but thermal aggregation was observed on heating above 85 °C. In addition, we reported that sole cysteine in C-terminal region plays a key role in the thermostability and thermal aggregation of Tth PPase [Kohaku, Y. et al. (2008) Natl.Sci.Res., 22, 75-84]. In this study, we approached the suppression of its thermal aggregation by error-prone PCR mutagenesis of whole molecule or C-terminal region. Firstly, we obtained thermostable four variants (Q119H/L162F, L162F, K173E and K159E/A170T) by error-prone PCR mutagenesis. Moreover, we examined thermostabilities of four variants in terms of the enzyme activity, tertiary and quaternary structure. Although conformation and quaternary structure of four variants were almost the same as those of wild type enzyme in native state, K173E and K159E/A170T variants showed higher thermostabilities than wild type in tertiary and quaternary structure. In particular, thermal aggregation of these two variants would be suppressed after heating at 85°C. Therefore, it was suggested that Lys159 and Lys173 in the molecular surface of C-terminal region may contribute to the formation of thermal aggregation of Tth PPase

Elucidation of the mechanism of subunit exchange in αB crystallin oligomers

AlphaB crystallin (αB-crystallin) is a key protein for maintaining the long-term transparency of the eye lens. In the eye lens, αB-crystallin is a “dynamical” oligomer regulated by subunit exchange between the oligomers. To elucidate the unsettled mechanism of subunit exchange in αB-crystallin oligomers, the study was carried out at two different protein concentrations, 28.5 mg/mL (dense sample) and 0.45 mg/mL (dilute sample), through inverse contrast matching small-angle neutron scattering. Interestingly, the exchange rate of the dense sample was the same as that of the dilute sample. From analytical ultracentrifuge measurements, the coexistence of small molecular weight components and oligomers was detected, regardless of the protein concentration. The model proposed that subunit exchange could proceed through the assistance of monomers and other small oligomers; the key mechanism is attaching/detaching monomers and other small oligomers to/from oligomers. Moreover, this model successfully reproduced the experimental results for both dense and dilute solutions. It is concluded that the monomer and other small oligomers attaching/detaching mainly regulates the subunit exchange in αB-crystallin oligomer

Thermostabilization by the Improvement of Intertrimeric Residues in Thermus thermophilus Inorganic Pyrophosphatase.

Inorganic pyrophosphatase (EC. 3.6.1.1) from Thermus thermophilus (Tth PPase)is a thermostable homohexamer of 174 amino acids，and its intertrimer interface is formed mainly by the symmetric α-helix A between subunits. Amino acids and their interactions composing intertrimer interface are different in hexameric Family I PPases，and then it was deduced that Tth PPase showed high thermostability because of stabilizing this interface by interactions of these residues. In this study，we focused on Thr138 and Ala141 residues in intertrimer interface of Tth PPase to confirm the relationship between intertrimeric residues and thermostability， and then improved their combination to His and Asp/Glu (HD or HE variant). As results，the HD variant showed the highest thermostability of enzyme activity，fluorescence spectra, and quaternary structure in the wild type Tth PPase and all variants. Especially，about 38% of hexamer and almost 40% of enzyme activity were observed in HD variant after heating even at 85℃. Therefore，we suggested that the conversion to a set of ionic His138 and Asp141 at intertrimer interface had increased the thermostability of Tth PPase，and then suppressed its thermal aggregation

Effect of an Oral Adsorbent, AST-120, on Dialysis Initiation and Survival in Patients with Chronic Kidney Disease

The oral adsorbent AST-120 has the potential to delay dialysis initiation and improve survival of patients on dialysis. We evaluated the effect of AST-120 on dialysis initiation and its potential to improve survival in patients with chronic kidney disease. The present retrospective pair-matched study included 560 patients, grouped according to whether or not they received AST-120 before dialysis (AST-120 and non-AST-120 groups). The cumulative dialysis initiation free rate and survival rate were compared by the Kaplan-Meier method. Multivariate analysis was used to determine the impact of AST-120 on dialysis initiation. Our results showed significant differences in the 12- and 24-month dialysis initiation free rate (P < 0.001), although no significant difference was observed in the survival rate between the two groups. In conclusion, AST-120 delays dialysis initiation in chronic kidney disease (CKD) patients but has no effect on survival. AST-120 is an effective therapy for delaying the progression of CKD