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Biomedical subjects

T Yamazaki

Publications and source records attributed to T Yamazaki.

At least 37 records · Page 2Linked to original sources
PubMed2004

Synthetic sulfonolipids deduced from sulfonoquinovosyl diacylglycerols of sea urchin reduces hepatic ischemia-reperfusion injury in rats.

BACKGROUND: In hepatic surgery and liver transplantation, ischemia-reperfusion (I/R) is an unavoidable process, and protection against hepatic I/R injury is a major unresolved problem. In this study, we investigated whether 3-O-(6-deoxy-6-sulfono-beta-D-glucopyranosyl)-1,2-di-O-acylglycerol bound to saturated C18 fatty acids (beta-SQAG9), which was derived from sea urchin intestines, could reduce this injury. This agent was recently reported to have immunosuppressive effects in allogeneic rat skin grafts. MATERIALS & METHODS: Male Lewis rats were divided into two experimental groups. Group 1 rats were injected with SQAG9 (50 mg/kg) into the penile vein 15 minutes before the induction of ischemia and into the portal vein just reperfusion. The same amounts of normal saline were injected into rats in the control group (group 2). Each experimental groups included six rats. Seventy percent hepatic ischemia (20 minutes) was induced by occluding the blood vessels and bile duct with a vascular clamp. For examination of hepatic function, serum levels of aspartate aminotransferase, (AST) alanine transaminase (ALT), and lactic dehydrogenase (LDH) were measured. In addition, histological examination was also assessed. RESULTS: Three hours after reperfusion, the mean plasma concentration of AST, ALT, LDH in group 1 was suppressed compared with group 2. Six hours after reperfusion, the hepatic damage in group 1 was mild in comparison with that in group 2. CONCLUSIONS: Our data demonstrated that SQAG-9 reduced the warm hepatic I/R injury.

Animals↗
PubMed2004

Quantitative high-resolution HAADF-STEM analysis of inversion boundaries in Sb(2)O(3)-doped zinc oxide.

[Formula: see text] -doped ZnO crystals including inversion boundaries were investigated by high-resolution high-angle annular-dark field (HAADF) scanning transmission electron microscopy (STEM). The images were analysed with the aid of the image simulation based on Bethe method and also the retrieval processing using deconvolution. Utility of these two approaches for the HAADF-STEM analysis is discussed.

Journal Article↗
PubMed2004

Role of surface amorphous film in high-resolution high-angle annular dark field STEM imaging.

A different scheme for high-angle annular dark-field scanning transmission electron microscopy image calculation of multilayers, such as a crystal covered by amorphous films, has been developed, in which intensities of electrons collected by an annular detector at each layer are evaluated by two kinds of optical potential for thermal diffuse scattering on the layer-by-layer representation. One beam condition caused by an amorphous structure changes the present method into a simplified method. Through a molecular dynamics study of amorphous SiO2, it is found that an off-axis cristobalite, regarded as one-beam condition, can be used for a model of amorphous SiO2 structure. Furthermore, we demonstrate how surface amorphous films adhering to a crystal reduce image contrast and show that a top surface amorphous film acts as changing defocus in coherent convergent electron beam.

Journal Article↗
PubMed2004

Symmetries in BF and HAADF STEM image calculations.

Reductions in bright-field (BF) scanning transmission electron microscopy (STEM) and high-angle annular dark-field (HAADF) STEM image calculations with the aid of Bloch wave symmetry are discussed under assumptions that an absorption potential is written by a local potential and a zero-order Laue zone lies parallel to the crystal surface. Translational symmetry allows us to take only partial incident beams in the first Brillouin zone instead of enormous number of partial incident beams in a large convergent disk. Two dimensional point group confines partial incident beams to an irreducible area in addition to factoring a dispersion matrix into noninteracting submatrices on a high symmetry line using the projection operator. The drastic reductions in computing time and memory enable us to readily calculate various BF STEM and HAADF STEM images. The validity and accuracy are demonstrated in comparisons with high resolution experimental BF STEM and HAADF STEM images.

Algorithms↗
PubMed2004

Inactivation of Chlamydia trachomatis and Chlamydia (Chlamydophila) pneumoniae by ozone.

AIMS: To clarify the inhibitory effects of ozone on Chlamydia trachomatis and C. pneumoniae. METHODS AND RESULTS: Cell culture was performed using HeLa229 cells for C. trachomatis, and Human Line cells for C. pneumoniae. C. trachomatis strain D/UW-3/Cx and C. pneumoniae strain AR-39 were used. Ozone water was generated by an ozone water dispenser and diluted to desired concentration just before each experiment. Preinoculation minimum cidal concentration (MCC) and postinoculation MCC methods were employed. In preinoculation MCC, chlamydial strains were treated with serially diluted ozone water followed by inoculation to cells. In postinoculation method, chlamydial strains were inoculated to cells and incubated for 24 h. Then infected cells were treated with ozone water, followed by additional incubation for 48 h. Complete inactivation was obtained in preinoculation MCC method at 0.5 ppm of ozone water for 30 s, or 4 ppm for 5 s. CONCLUSION: Ozone at a concentration of 4 ppm was enough for immediate inactivation of both C. trachomatis and C. pneumoniae. SIGNIFICANCE AND IMPACT OF THE STUDY: Ozone water at 4 ppm should be applicable for prevention of C. trachomatis urogenital infections.

Cell Line↗
PubMed2004

Technical note: a comparison of antiscatter grids for digital radiography.

The use of digital radiography (DR) systems offers a number of advantages over film-screen detectors. One potential disadvantage, however, is that some fixed DR systems do not allow the user to change the antiscatter grid to suit the imaging task. Instead, the user must choose the grid at the time of purchase. Six grids, which are offered as installation options for one commercial fixed-room DR system, were experimentally evaluated, using a range of scatter conditions and tube voltages. In addition, three grids, which are available with a portable DR system in which the user can change the grid to suit the imaging task, were also evaluated. The grids were compared using the primary transmission, scatter fraction, and calculated signal-to-noise improvement factor (SIF). It was found that the grids with low atomic number interspace and cover material had an SIF up to 15% higher than did the grids with aluminium interspace and cover material; the grid with a grid ratio of 12:1 had the highest SIF for all tube voltages and scatter conditions tested here. This 12:1 grid probably represents a good general-purpose non-removable grid in DR.

Phantoms, Imaging↗
PubMed2004

A MEK inhibitor (U0126) markedly inhibits direct liver invasion of orthotopically inoculated human gallbladder cancer cells in nude mice.

Primary cancer of the gallbladder is not unusual. Most cases of gallbladder cancer are found at an advanced stage, accompanied by the invasion to the liver, metastases to the lymph nodes and distant organs, and peritoneal dissemination. In this study, we first examined the effect of mitogen-activated protein kinase kinase (MEK) inhibitors on the production of matrix metalloproteinases (MMPs), urokinase-type plasminogen activator (uPA), and tissue inhibitors of metalloproteinases (TIMPs) in a human gallbladder cancer cell line, NOZ cells in vitro. MEK inhibitors (PD98059 and U0126) inhibited the production of MMP-2, MMP-9 and high MW uPA, and upregulated TIMPs (TIMP-1, TIMP-2 and TIMP-3). Subsequently, we examined the effect of U0126 on invasion and metastasis of orthotopically inoculated NOZ cells in nude mice. Direct liver invasion by cancer cells was detected in all of the mice in the control group, but in only one mouse in the U0126-treated group. Most of the primary tumors in the U0126-treated group expanded to the liver, but did not invade into the liver. Vessel invasion in the liver was evident in 4 out of 5 mice in the control group, but in only one mouse in the U0126-treated group. Lymph node metastases and peritoneal dissemination were recognized in all of the mice in both groups. All 5 mice in the U0126-treated group, and 4 out of 5 mice in the vehicle control group, had metastases in the lungs. The present results suggest that a MEK inhibitor, U0126, prolonged the survival of the mice with NOZ tumor by inhibiting direct liver invasion and vessel invasion of the cancer cells via down-regulation of the matrix degrading ability of the cancer cells.

Animals↗
PubMed2003

Direct measurement of transition frequencies in isolated pHe+ atoms, and new CPT-violation limits on the antiproton charge and mass.

A radio frequency quadrupole decelerator and achromatic momentum analyzer were used to decelerate antiprotons and produce p4He+ and p3He+ atoms in ultra-low-density targets, where collision-induced shifts of the atomic transition frequencies were negligible. The frequencies at near-vacuo conditions were measured by laser spectroscopy to fractional precisions of (6-19) x 10(-8). By comparing these with QED calculations and the antiproton cyclotron frequency, we set a new limit of 1 x 10(-8) on possible differences between the antiproton and proton charges and masses.

Journal Article↗
PubMed2003

Experimental and clinical study of a holmium: YAG laser with adjustable pulse duration.

BACKGROUND: The holmium:YAG laser is used for treatment of urolithiasis, transurethral laser ablation for benign prostate hypertrophy and bladder tumor. The pulse duration was fixed in the previous Ho:YAG laser systems. We have evaluated more practical pulse durations to disintegrate the stone. The SPHINX Ho40 (Heraeus Corporation) can change the pulse duration freely in the range from 150 microsec. to 800 microsec. MATERIALS AND METHODS: 1) We measured the total energy to perforate through stone models at three different pulse durations (150, 300, 600 microsec.). 2) We experimented with the energy of each single pulse and the power of the shock wave. 3) We observed thermogenesis during the lithotripsy for each pulse duration. 4) Disintegration effects of Ho:YAG are compared with other lithotripsy systems in clinical cases. RESULTS: 1) It was possible that the smallest amount of the total energy went through the fragment at the pulse duration 150 microsec. 2) The maximum amount of energy of the wave is higher when the pulse duration is short. Although the amount of energy was 12.6 V, the amounts of energy at 800 microsec decreased with a pulse duration 150 microsec. to 6.46 V which was about 40 % 3) The highest temperatures achieved when the irradiation of laser was started and finished were compared. The shorter the pulse duration was, the higher was the peak power. The shock wave was also more effective to disintegrate stones on using short pulse durations. 4) The individual clinical success rates are Ho:YAG (85.1 %), Alexandrite (80.6 %) and Lithoclast (74.5 %).

Holmium↗
PubMed2003

Structure determination of minor red pigment in carthamus red colorant isolated by preparative LC/MS.

Carthamin is a well-known major pigment in carthamus red colourant. When analysed by HPLC on an ODS column, the colorant separated into two distinct reddish pigments, with both components having almost identical photodiode array spectra. LC/MS analysis suggested one of the compounds was carthamin, whilst the other was an unknown minor pigment. The minor pigment was purified and isolated from the colorant by preparative LC/MS collecting the faction based on monitoring the deprotonated molecule [M-H](-) m/z 953 in electrospray negative-ion mode. The structure was elucidated as a hydroxyethyl ether of carthamin, a novel compound, by means of NMR and HR-FAB-MS analyses.

Carthamus tinctorius↗
PubMed2003

The clinical significance of sialyl Lewis antigen expression in the spread of gastric cancer. Flow cytometric DNA analysis.

We previously reported significant relationships between sialyl Lewis antigen expression on gastric cancer cells and both hepatic metastasis and clinical prognosis. The purpose of this study was to compare the expression of sialyl Lewis antigens on gastric cancer cells to elucidate the possible role of sialyl Lewis antigens in predicting the spread of a tumor with regard to histological findings. Subjects consisted of 38 patients with gastric cancer. For comparison we measured the values for sialyl Lewisa (sLea) and sialyl Lewisx (sLex) expression on the surface of about 10,000-30,000 cancer cells. Monoclonal antibodies CA19-9 and KM-93 were used to determine the frequency (%) and quantity (channel) of the expression by flow cytometry. We assessed the correlation of sLea and sLex expression with histological findings (depth of tumor invasion (pT), lymphatic invasion (ly), venous invasion (v), and lymph node metastasis (pN)), by comparing sLea and sLex expression in relation to the grade of histological findings. A significant relationship was found between lymphatic invasion and the frequency of sLea expression (r = 0.40, p<0.05). The mean values of sLea frequency in cases categorized as ly 2 (36.30) and ly 3 (31.81) were statistically higher than those in ly 1 cases (12.74) (p<0.05). A significant relationship was also observed between lymph node metastasis and the frequency of sLea expression (r = 0.46, p<0.01). The mean value of sLea frequency in pN 3 cases (44.14) was statistically higher than those in pN 0 (17.11) and pN 1 (19.03) cases (p<0.05). Neither the depth of tumor invasion nor venous invasion showed any correlation with the expression of sialyl Lewis antigens. In conclusion the frequency of sLea expression on the surface of gastric cancer cells was greater in those patients who developed lymphatic invasion and lymph node metastasis. However, the mechanism by which sialyl Lewisa expression is upregulated remains unclear.

Adult↗
PubMed2002

Hyperfine structure of antiprotonic helium revealed by a laser-microwave-laser resonance method.

Using a newly developed laser-microwave-laser resonance method, we observed a pair of microwave transitions between hyperfine levels of the (n,L)=(37,35) state of antiprotonic helium. This experiment confirms the quadruplet hyperfine structure arising from the interaction of the antiproton orbital angular momentum, the electron spin and the antiproton spin as predicted by Bakalov and Korobov. The measured frequencies of nu(+)(HF)=12.895 96+/-0.000 34 GHz and nu(-)(HF)=12.924 67+/-0.000 29 GHz agree with recent theoretical calculations on a level of 6x10(-5).

Journal Article↗
PubMed2002

Primary populations of metastable antiprotonic (4)He and (3)He atoms.

Initial distributions of metastable antiprotonic (4)He and (3)He atoms over principal (n) and angular momentum (l) quantum numbers have been deduced using laser spectroscopy experiments. The regions n = 37-40 and n = 35-38 in the two atoms account for almost all of the observed fractions [(3.0 +/- 0.1)% and (2.4 +/- 0.1)%] of antiprotons captured into metastable states.

Journal Article↗
PubMed2002

Deeply bound 1s and 2p pionic states in 205Pb and determination of the s-wave part of the pion-nucleus interaction.

We observed well-separated 1s and 2p pi(-) states in 205Pb in the 206Pb(d,3He) reaction at T(d) = 604.3 MeV. The binding energies and the widths determined are B(1s) = 6.762+/-0.061 MeV, Gamma(1s) = 0.764(+0.154)(-0.171) MeV, B(2p) = 5.110+/-0.045 MeV, and Gamma(2p) = 0.321(-0.062)(+0.060) MeV. They are used to deduce the real and imaginary strengths of the s-wave part of the pion-nucleus interaction, which translates into a positive mass shift of pi(-) in 205Pb.

Journal Article↗
PubMed2002

In vitro assay of hydrolysis and chlorohydroxy derivatives of bisphenol A diglycidyl ether for estrogenic activity.

Bisphenol A diglycidyl ether (BADGE) is an epoxy resin monomer. Epoxy-based solution coatings are used in many applications as additives for a variety of plastic coatings in food packaging. It is well known that unreacted BADGE can migrate from epoxy-based packing materials into foods. Not only BADGE but also its derivatives can easily migrate into foods and it is likely that we intake BADGE and its derivatives through food or drink. Recently, endocrine disrupting chemicals (EDCs) have attracted attention because they have been shown to affect reproduction in wildlife. The estrogenic activity of BADGE derivatives has not previously been investigated. Therefore, we investigated the estrogenic activity of the BADGE derivatives, dihydrolysed BADGE (BADGE-4OH) and chlorohydroxy BADGE (BADGE-2Cl), using breast cancer cell (T47D) proliferation assay and estrogen receptor (ER) (alpha) binding assay. These chemicals exhibited T47D cell proliferation at concentrations of 10(-14)-10(-4) M. However, these chemicals did not bind to ER (alpha) in the binding assay.

Benzhydryl Compounds↗
PubMed2002

Effect of small crystal tilt on atomic-resolution high-angle annular dark field STEM imaging.

Using a slightly tilted convergent electron beam, high-angle annular dark field scanning transmission electron microscopy observations have been performed of a [0 11]-oriented Si crystal. A small tilt of the crystal zone axis with respect to the coma-axis of the probe-forming lens causes a difference in intensity between bright spots of a Si dumbbell. The semiangle of the beam probe and the tilting angle with respect to the specimen hormal were determined by means of convergent beam micro-diffraction. The simulation using these parameters accounts for the image contrasts satisfactorily.

Journal Article↗
PubMed2002

Deconvolution processing of HAADF STEM images.

A deconvolution processing of high-resolution high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) images, combined with maximum entropy method, is applied to two experimental [0 11]-Si images; one having unresolved dumbbells and the other having resolved dumbbells and artificial bright spots. The deconvoluted images for these images show bright spots corresponding to the projected atomic columns and no artificial bright spots. Thus, the deconvolution processing provides almost a real projected atomic structure by eliminating effects of the probe function from HAADF STEM images.

Journal Article↗