Yokohama Soei University

Yokohama-shi, Japan

Yokohama Soei University

Yokohama-shi, Japan
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Nishimura M.,National Hospital Organization Chiba East National Hospital | Kato Y.,National Hospital Organization Nagoya Medical Center | Tanaka T.,National Hospital Organization Mie Chuo Medical Center | Todo R.,National Hospital Organization Osaka Medical Center | And 6 more authors.
Hypertension Research | Year: 2013

The Home Blood Pressure for Diabetic Nephropathy (HBP-DN) study is a prospective cohort study to determine the optimal home blood pressure (HBP) required to improve the prognosis of type 2 diabetic patients with microalbuminuria. The glomerular filtration rate (GFR) is heterogeneous in microalbuminuric diabetic patients. The first step of the HBP-DN study explored the significance of estimating GFR for the identification of patients for whom HBP measurement would be more helpful. The patients were divided into two groups based on their estimated GFR (eGFR): a low eGFR group (eGFR <60 ml min -1 per 1.73 m2, N=75) and a preserved eGFR group (eGFR ≥60 ml min-1 per 1.73 m2, N=193). HBP, variability of HBP and a previous history of vascular complications were compared between the two groups. The number of antihypertensive drugs used for the patients and the s.d. of home systolic blood pressure (HSBP) in the low eGFR group were significantly higher than those in the preserved eGFR group. A stepwise multiple linear regression analysis also revealed that the low eGFR group was independently correlated with the s.d. of HSBP. A multiple logistic regression analysis revealed that a low eGFR was an independent risk factor for coronary heart disease and advanced retinopathy. Estimating the GFR is important to identify patients with elevated blood pressure variability, as well as those with a high risk of vascular complications. Measuring HBP would be more helpful for the effective and safe treatment of hypertension in patients with a low eGFR than in those with a preserved eGFR. © 2013 The Japanese Society of Hypertension. All rights reserved.


Suzuki R.,Yokohama City University | Kishi T.,Yokohama City University | Tsukashima S.,Yokohama City University | Tachibana M.,Yokohama City University | And 2 more authors.
Philosophical Magazine | Year: 2016

Hardness and slip systems by an indentation method were investigated on different habit planes of orthorhombic hen egg-white lysozyme (O-HEWL) crystals containing water. A dependence of the hardness on the water-evaporation time exhibits three stages as incubation, transition and saturated ones, as tetragonal (T)-HEWL crystals reported previously. The hardness values of (1 1 0), (0 1 0) and (0 1 1) habit planes of O-HEWL in the incubation stage or wet condition exhibits 6, 8 and 10 MPa, respectively. The hardness depends on indented planes but it is independent of the air-humidity and crystal volumes. These values correspond to the intrinsic hardness for O-HEWL crystals containing water. In the incubation stage, the slip traces are clearly observed around the indentation mark and the corresponding six kinds of slip systems are identified to be {0 1 1}<1 0 0>, {1 1 0}<1 1 0>, {0 1 1}<0 1 1>, {1 1 0}<0 0 1>, {1 0 0}<0 0 1> and {0 1 0}<0 0 1>. © 2016 Informa UK Limited, trading as Taylor & Francis Group.


Koizumi H.,Tohoku University | Suzuki R.,Yokohama City University | Tachibana M.,Yokohama City University | Tsukamoto K.,Osaka University | And 5 more authors.
Crystal Growth and Design | Year: 2016

We show that the extinction effect explained by the dynamical theory of diffraction must be considered even in the case of protein crystals. Equal-thickness fringes, which are attributed to the Pendellösung effect, were clearly observed in the region of a tapered glucose isomerase crystal with wedge-like edges using X-ray topography carried out with a beam of monochromatic synchrotron radiation. This indicates that the perfection of this glucose isomerase crystal is high enough to produce this dynamical theory-related effect: this surely leads to difficulty in the collection of accurate integrated intensities of diffraction spots for X-ray structural analysis. Therefore, it is important to determine whether the crystal quality of a protein crystal under analysis is adequate to obtain accurate three-dimensional structures of protein molecules for X-ray structural analyses. We show that X-ray diffraction rocking-curve measurements can provide clues for this determination. © 2016 American Chemical Society.


Koizumi H.,Tohoku University | Uda S.,Tohoku University | Fujiwara K.,Tohoku University | Tachibana M.,Yokohama City University | And 2 more authors.
Crystal Growth and Design | Year: 2014

X-ray diffraction rocking-curve measurements were performed on tetragonal hen egg white (HEW) lysozyme crystals grown with and without the application of an external alternating current (AC) electric field. Analysis of the full width at half-maximum (fwhm) of the rocking curves indicated that misorientation between subgrains, |θ - φ|, and local strain, 〈ε〉, in the crystals contributed to the broadening of the experimentally determined rocking curves for the tetragonal HEW lysozyme crystals. In particular, the data suggested that imperfections in tetragonal HEW lysozyme crystals are predominantly caused by misorientation between subgrains. Moreover, it was determined that improvements in the quality of tetragonal HEW lysozyme crystals, as assessed by a decrease in the misorientation between subgrains, can be achieved by imposing a 1 MHz electric field during crystal growth. This paper also discusses the origin of subgrain misorientation in light of the incorporation of impurities into protein crystals. (Figure Presented). © 2014 American Chemical Society.


Koizumi H.,Tohoku University | Uda S.,Tohoku University | Fujiwara K.,Tohoku University | Tachibana M.,Yokohama City University | And 2 more authors.
Journal of Applied Crystallography | Year: 2015

The effect of a 20kHz external electric field on the quality of tetragonal hen egg white (HEW) lysozyme crystals was investigated using X-ray diffraction rocking-curve measurements. The full width at half-maximum was found to be larger for high-order reflections but smaller for low-order reflections. In particular, it was revealed that a large amount of local strain is accumulated in tetragonal HEW lysozyme crystals grown under an applied field at 20kHz. Comparison with previous results obtained for crystals grown with an applied field at 1MHz [Koizumi, Uda, Fujiwara, Tachibana, Kojima & Nozawa (2013). J. Appl. Cryst. 46, 25-29] indicated that improvement of the protein crystal quality could be achieved by selection of an appropriate frequency for the applied electric field, which has a significant effect on the growth of the solid. © 2015 International Union of Crystallography.


Koizumi H.,Tohoku University | Uda S.,Tohoku University | Fujiwara K.,Tohoku University | Tachibana M.,Yokohama City University | And 2 more authors.
Journal of Applied Crystallography | Year: 2013

X-ray diffraction rocking-curve measurements were performed on tetragonal hen egg white lysozyme (HEWL) crystals grown with and without application of an external alternating current (AC) electric field, and then the crystal quality was assessed by the FWHMs of each rocking-curve profile. The FWHMs for HEWL crystals grown with an external electric field were smaller than those for crystals grown without. In particular, the average FWHM for the 12 12 0 reflection with an external electric field (0.0034°) was significantly smaller than that without (0.0061°). This indicates that the crystal quality of HEWL crystals was improved by application of the external AC electric field. This crystallization technique can be expected to enhance the resolution of protein molecule structure analysis by X-ray diffraction. © 2013 International Union of Crystallography.


Koizumi H.,Tohoku University | Uda S.,Tohoku University | Tachibana M.,Yokohama City University | Tsukamoto K.,Osaka University | And 2 more authors.
Crystal Growth and Design | Year: 2016

In this study, we show using X-ray diffraction (XRD) rocking-curve measurements that local strain in tetragonal hen egg white (HEW) lysozyme crystals can be removed to a large degree by utilizing seed crystals cross-linked with glutaraldehyde. We also find that misorientation between subgrains and subgrain size decrease when employing cross-linked seed crystals, which suggests that subgrain formation in tetragonal HEW lysozyme crystals can be controlled using this technique. The ideal mosaic structure of proteins that enables the collection of accurate integrated intensities of the diffracted waves is also discussed using tetragonal HEW lysozyme crystals as a model protein. © 2016 American Chemical Society.


Koizumi H.,Tohoku University | Uda S.,Tohoku University | Fujiwara K.,Tohoku University | Tachibana M.,Yokohama City University | And 2 more authors.
Crystals | Year: 2016

X-ray diffraction (XRD) rocking-curves were measured for tetragonal hen egg white (HEW) lysozyme crystals grown with and without application of an external electric field, and the crystal quality was assessed according to the full width at half-maximums (FWHMs) of each rocking-curve profile. The average FWHMs for tetragonal HEW lysozyme crystals grown with an external electric field at 1 MHz were smaller than those for crystals grown without, especially for the 12 12 0 reflection. The crystal homogeneity of the tetragonal HEW lysozyme crystals was also improved under application of an external electric field at 1 MHz, compared to that without.Improvement of the crystal quality of tetragonal HEW lysozyme crystals grown under an applied field is discussed with a focus on subgrain formation. In addition, the origin of subgrain misorientation is also discussed with respect to the incorporation of impurities into protein crystals. © 2016 by the authors; licensee MDPI, Basel, Switzerland.


PubMed | Tohoku University, Yokohama City University, Citizen Holdings Company and Yokohama Soei University
Type: Journal Article | Journal: Physical review. E, Statistical, nonlinear, and soft matter physics | Year: 2014

The ultrasonic sound velocities of cross-linked orthorhombic hen egg-white lysozyme (HEWL) crystals, including a large amount of water in the crystal, were measured using an ultrasonic pulse-echo method. As a result, seven elastic constants of orthorhombic crystals were observed to be C11 = 5.24 GPa, C22 = 4.87 GPa, C12 = 4.02 GPa, C33 = 5.23 GPa, C44 = 0.30 GPa, C55 = 0.40 GPa, and C66 = 0.43 GPa, respectively. However, C13 and C23 could not be observed because the suitable crystal planes could not be cut from bulk crystals. We conclude that the observed elastic constants of the cross-linked crystals are coincident with those of the intrinsic crystals without cross-linking. Moreover, the characteristics of the elastic constants in orthorhombic HEWL crystals are due to the fact that the shear elastic constants, C44, C55, and C66, are softer than in tetragonal crystals. That is, the shear components, C44, C55, and C66, are one half of those of the tetragonal crystals.


Wako K.,Yokohama Soei University | Fujii D.,Yokohama City University | Tsukashima S.,Yokohama City University | Kishi T.,Yokohama City University | And 2 more authors.
Journal of Crystal Growth | Year: 2014

The crystal distortion of monoclinic hen egg-white lysozyme (HEWL) crystals was observed by the X-ray digital topography. The local rocking curves were obtained by the series of the topographic images. The single, double, triple, and multiple peaks of the local rocking curves were observed. The mapping of the full width of the one tenth maximum (FW10M) of the local rocking curves was obtained. It was found that the magnitude of FW10M depended on the distance of the peak splitting. The distribution of the distortion in the monoclinic HEWL crystals was investigated by the analysis of the local rocking curves. © 2014 Elsevier B.V.

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