Biomedical subjects

T Miyazaki

Publications and source records attributed to T Miyazaki.

At least 19 recordsLinked to original sources

PubMed2006

RhoA and RhoC proteins promote both cell proliferation and cell invasion of human oesophageal squamous cell carcinoma cell lines in vitro and in vivo.

There is growing evidence that Rho proteins are deregulated by overexpression in tumours; and according to some reports, this correlates with disease progression. Our previous clinical study had demonstrated a correlation between RhoA expression and tumour progression in oesophageal squamous cell carcinoma (ESCC). These findings prompted us to study, using nude mice, pathological roles of Rho proteins in human ESCC cells. Western blot analysis in ESCC cell lines, in addition to cell proliferation and in vitro migration assays, were performed to observe the malignant potential of RhoA and RhoC in untransfected and transfected cells. Constitutively active RhoA, RhoC and dominant negative RhoA (dnRhoA) proteins were transfected to ESCC (TE-1 and TE-2) cells. The stably transfected cells were injected into nude mice, and the growth and metastasis of these cells to the lungs were analysed. Tumour tissues were then examined using immunohistochemical methods for proteins Ki-67 (MIB-1), FAK, MMP-1, MMP-9 and TIMP-3. Protein levels of RhoA and RhoC in ESCC cell lines were visualised by Western blotting, and showed highest expression in TE-2 cells. Results from the migration assay illustrated that both RhoA and RhoC play a role in migration of ESCC cells. In TE-2 transfected cells, RhoC showed greater migration compared to RhoA. By using an experimental metastasis model in nude mice, RhoA was found to promote more tumour growth than RhoC, whereas RhoC induced lung metastasis in comparison to RhoA. Ki-67 labelling index was used to evaluate the proliferation potential of tumour tissue inoculated from nude mice. In TE-2 cells RhoA gave a proliferation capacity of 24.8+/-0.5, which was significantly higher than those of TE-2 RhoC 10+/-0.4 (P<0.01). Strong immunoreactivity for FAK, MMP-1 and MMP-9 proteins was present in all tumour cells. By contrast, loss of TIMP-3 expression was observed in all tumour cells. In conclusion, our results indicate that pro-oncogenic Rho proteins are involved in promoting tumour growth, cell migration and metastasis in human ESCC cells in nude mice. The results from this study suggest that active Rho proteins may induce a transforming effect that leads to a malignant phenotype.

Animals↗

PubMed2006

Effect of ZnO addition on bioactive CaO-SiO2-P2O5-CaF2 glass-ceramics containing apatite and wollastonite.

Some ceramics show bone-bonding ability, i.e. bioactivity. Apatite formation on ceramics is an essential condition to bring about direct bonding to living bone when implanted into bony defects. A controlled surface reaction of the ceramic is an important factor governing the bioactivity and biodegradation of the implanted ceramic. Among bioactive ceramics, glass-ceramic A-W containing apatite and wollastonite shows high bioactivity, as well as high mechanical strength. In this study, glass-ceramics containing zinc oxide were prepared by modification of the composition of the glass-ceramic A-W. Zinc oxide was selected to control the reactivity of the glass-ceramics since zinc is a trace element that shows stimulatory effects on bone formation. Glass-ceramics were prepared by heat treatment of glasses with the general composition: xZnOx(57.0-x)CaOx35.4SiO(2)x7.2P(2)O(5)x0.4CaF(2) (where x=0-14.2mol.%). Addition of ZnO increased the chemical durability of the glass-ceramics, resulting in a decrease in the rate of apatite formation in a simulated body fluid. On the other hand, the release of zinc from the glass-ceramics increased with increasing ZnO content. Addition of ZnO may provide bioactive CaO-SiO(2)-P(2)O(5)-CaF(2) glass-ceramics with the capacity for appropriate biodegradation, as well as enhancement of bone formation.

Apatites↗

PubMed2006

Effect of perioperative steroid therapy on the postoperative course of patients with oesophageal cancer.

BACKGROUND: Perioperative steroid therapy is often used in oesophageal cancer surgery and we evaluate the effect of this therapy on the secretory leukocyte protease inhibitor levels in the lungs (a major antiprotease in the conducting airways) and postoperative course in oesophageal cancer patients. METHODS: Twenty-one patients operated on for oesophageal cancer in 2003-2004 were treated with perioperative steroid therapy (250 mg of methylprednisolone intravenously 1 h before the operation). Fifteen consecutive patients operated on in 2002 served as a control group. Secretory leukocyte protease inhibitor in bronchoalveolar lavage fluid and the postoperative course in the two groups were compared. RESULTS: The mortality rate was 0% and there was no significant difference in the morbidity rate between the two groups. Days of intubation and systemic inflammatory response syndrome were significantly shorter for the steroid group. The bronchoalveolar lavage fluid secretory leukocyte protease inhibitor level was significantly higher in the steroid group than in the control group on postoperative days 2 and 3. The secretory leukocyte protease inhibitor level on postoperative day 3 was remarkably lower for the patients intubated for > or = 5 days and for those with pulmonary complications. CONCLUSION: Perioperative steroid therapy increased the bronchoalveolar lavage fluid secretory leukocyte protease inhibitor level and reduced the days of intubation and systemic inflammatory response syndrome in patients with oesophagectomy.

Bronchoalveolar Lavage Fluid↗

PubMed2006

Superconductivity of doped Ar@C60.

The synthesis of a mg amount of pure argon containing fullerene allowed the synthesis of the first endohedral superconductors with critical temperatures lower than expected, an indication of the strong influence of the argon atom on the C60 cage.

Journal Article↗

PubMed2006

[Surgical treatment for stage IV lung cancer].

OBJECTIVE: To find out the optimal surgical indication in stage IV lung cancer patients, we evaluated them retrospectively. METHODS & RESULTS: From 1975 to 2005, 62 patients without multiple metastases were operated at our hospital. The most common histological type was adenocarcinoma (67.7%). The metastatic lesions were lung (33.9%), brain (24.2%), liver, bone, adrenal gland and so on. The overall survival rate of stage IV lung cancer was 10.4% at 5-year. Five-year survival for patients with lung or brain metastasis who had no lymph node metastasis were significantly more superior than those with lymph node metastasis (p=0.0389, 0.0021). Four of 62 patients had 5-year survival. Two were lung and the others were brain and adrenal gland metastasis without lymph node metastasis. CONCLUSION: Stage IV lung cancer with lung or brain or adrenal gland metastasis without lymph node metastasis should be resected.

Adenocarcinoma↗

PubMed2005

An epistatic effect of the female specific loci on the development of autoimmune vasculitis and antinuclear autoantibody in murine lupus.

OBJECTIVE: To identify the genetic loci regulating the incidence and severity of renal autoimmune vasculitis developed in murine lupus. METHODS: Vasculitis of renal arteries was histopathologically evaluated in MRL/Mp-Fas(lpr) (MRL/lpr), C57BL/6-Fas(lpr) (B6/lpr), (MRL/lpr x B6/lpr) F1, and MRL/lpr x (MRL/lpr x B6/lpr) F1 backcross mice. Using genomic DNA samples of the backcross mice, genome-wide scans, association studies, and linkage analyses were carried out based on genotypes of polymorphic microsatellite markers. Correlations of vasculitis grade and levels of various autoantibodies were also evaluated. RESULTS: Two recessive susceptibility loci of the MRL allele were identified on chromosomes 4 and 1, which had previously been defined as the autoimmune related loci termed Arvm1 and Sle-1/Nba2, respectively. The former was epistatic to the latter in a female specific manner. The titre of antinuclear autoantibody (ANA) in IgG class, but not ANA in IgM class or anti-dsDNA in either IgG or IgM class, correlated significantly with vasculitis grade. CONCLUSIONS: The present loci have been reported in previous studies using a different set of murine strains, suggesting that they are of importance in the development of autoimmune vasculitis in murine models. The concomitance of autoimmune vasculitis and IgG ANA suggests a shared genetic factor regulating these traits.

Animals↗

PubMed2005

Comparative characterization study of microporous carbons by HRTEM image analysis and gas adsorption.

The present work presents a useful comparison of micropore size distributions (MPSDs) obtained from gas adsorption and image analysis of high-resolution transmission electron micrographs. It is shown that the MPSD obtained for a chemical activated carbon is concordant with that obtained from CO2 adsorption. In addition, this technique has allowed us to obtain the MPSD of a carbon molecular sieve (CMS) prepared in our laboratory by a copyrolysis process, which could only be characterized by CO2 adsorption at 273 K (not by N2 adsorption at 77 K due to diffusional problems). The MPSD obtained by high-resolution transmission electron microscopy (HRTEM) for the CMS is wider than that obtained by CO2 adsorption, suggesting that HRTEM is detecting the closed porosity existing in this sample, which is not accessible to gas adsorption. The existence of closed porosity in the CMS is explained considering the preparation method used. Thus, HRTEM combined with image analysis seems to be useful for structural analysis of narrow micropores including closed porosity.

Journal Article↗

PubMed2005

Synthesis of bioactive PMMA bone cement via modification with methacryloxypropyltri-methoxysilane and calcium acetate.

Bone cement consisting of polymethylmethacrylate (PMMA) powder and methylmethacrylate (MMA) liquid is clinically used for fixation of implants such as artificial hip joints. However, it does not show bone-bonding ability, i.e., bioactivity. The lack of bioactivity would be one of factors which cause loosening between the cement and the implant. The present authors recently showed the potential of bioactive PMMA-based bone cement through modification with gamma-methacryloxypropyltrimethoxysilane (MPS) and calcium acetate. In this study, the effects of the kinds of PMMA powder on setting time, apatite formation and compressive strength were investigated in a simulated body fluid (Kokubo solution). The cement modified with calcium acetate calcined at 220 degrees C could set within 15 min when the PMMA powder had an average molecular weight of 100,000 or less. The addition of calcium acetate calcined at 120 degrees C in the PMMA powder required a much longer period for setting. The modified cements formed an apatite layer after soaking in the Kokubo solution within 1 day for cement starting from PMMA powder with a molecular weight of 100,000 or less. Compressive strengths of the modified cements were more than 70 MPa for cements starting from 100,000 and 56,000 in molecular weight. After soaking in Kokubo solution for 7 days, the modified cement consisting of PMMA powder of 100,000 in molecular weight showed a smaller decrease in compressive strength than that consisting of 56,000 in molecular weight. These results indicate that bioactive PMMA cement can be produced with appropriate setting time and mechanical strength when PMMA powders with a suitable molecular weight are used. Such a type of design of bioactive PMMA bone cement leads to a novel development of bioactive material for bone substitutes.

Acetates↗

PubMed2005

Bonelike/PLGA hybrid materials for bone regeneration: preparation route and physicochemical characterisation.

Bonelike/PLGA hybrid materials have been developed using gamma-MPS as silane-coupling agent between the inorganic and organic phases for controlled drug delivery applications. Silanization showed to be more effective when cyclohexane was used as a non-polar solvent (nP method) due to a chemical interaction between Bonelike, and the silane film, while by using a 95/5 (V/V) methanol/water as a polar solvent (P method), a much thinner film was achieved. Functional groups of PLGA, such as the carbonyl group (C=O), were identified using Raman and FTIR-ATR analysis and therefore these groups may be used to link therapeutic molecules. These novel hybrid materials prepared by combining silanization and post-hybridisation processes are expected to find use in medical applications of bone regeneration and as drug delivery carrier for therapeutic molecules.

Bone Regeneration↗

PubMed2005

Correlation between RhoA overexpression and tumour progression in esophageal squamous cell carcinoma.

AIMS: The aim of this study was to clarify the clinico-pathologic outcome and prognostic significance of RhoA in esophageal squamous cell carcinoma (ESCC). METHODS: Immunohistochemical staining for RhoA was performed on surgical specimens obtained from 122 patients with ESCC. RESULTS: There were significant correlations among RhoA overexpression and TNM clinical classification (depth of invasion, P=0.028; presence of regional lymph node metastasis, P=0.009; presence of distant metastasis, P=0.003; staging P=0.006), lymphatic invasion (P=0.002), and blood-vessel invasion (P=0.004). The five-year survival rates for ESCC patients with RhoA overexpression were significantly lower than those in patients with RhoA under-expression (P=0.002). CONCLUSIONS: Our results demonstrated immunohistochemically that the expression of RhoA protein appeared to be correlated with tumour progression of ESCC. Patients with RhoA overexpression tended to have poor prognosis compared with patients with RhoA under-expression.

Adult↗

PubMed2005

Effects of single and long-term administration of wheat albumin on blood glucose control: randomized controlled clinical trials.

OBJECTIVE: To examine the effects of single and long-term administration of wheat albumin (WA) on blood glucose levels and blood glucose control, respectively. DESIGN: Randomly arranged crossover trial for single administration in healthy subjects and double-blinded randomized controlled trial for long-term administration (3 months) in diabetic patients. In vitro alpha-amylase inhibitory activity of WA was also determined. SETTING: Central Research Laboratories of Nisshin Flour Milling Co. Ltd. (Saitama, Japan) for single administration and Aiwa Clinic (Saitama, Japan) for long-term administration. SUBJECTS: A total of 12 healthy adult male volunteers for the single administration and 24 type II outpatient diabetics with mild hyperglycemia for the long-term administration. INTERVENTIONS: Subjects took soups containing 0, 0.25, 0.5, and 1.0 g WA before test meals for single administration, and patients took soups with or without 0.5 g WA before every meal for the long-term (3 months) administration. RESULTS: In vitro alpha-amylase inhibitory activity of WA was 150 times that of wheat flour. In the single administration experiment, WA suppressed peak postprandial blood glucose levels in a dose-dependent manner: 31, 47, and 50% reduction after 0.25, 0.5, and 1.0 g administrations, respectively. In the long-term administration, 0.5 g of WA did not affect fasting blood glucose levels, whereas it reduced hemoglobin A1c levels. No significant adverse effects such as hypoglycemia or gastrointestinal disturbances were observed in the two experiments. CONCLUSION: In the treatment of type II diabetic patients, WA might be a useful functional food, which, with diet and exercise, could help to improve blood glucose control without any critical adverse effects.

Administration, Oral↗

PubMed2005

Evidence for involvement of p59fyn in fasting-induced thymic involution.

p59fyn, a member of the src-family protein tyrosine kinase, is expressed abundantly in thymus. We examined the possible involvement of p59fyn in thymic involution induced by a fasting stress in Fyn-/- mice. An acute 48 h fast resulted in severe atrophy of the thymus and a marked decrease of the total thymocyte number with depletion of the CD4+CD8+[double positive (DP)] population in Fyn+/+ (control) mice. A remarkable increase in terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling-positive signals was detected in the fasted group of control mice. However, these findings were not observed in Fyn-/- mice. Interestingly, MRL/MPJ-lpr/lpr, a Fas-deficient model animal, also showed no significant decrease of DP cell numbers in the fasted group. p59fyn is known to interact with Fas signalling, and these findings suggest that p59fyn is involved in fasting-induced thymic involution, raising the possibility that Fas/p59fyn-mediated signalling may, at least partially, be associated with the phenomenon.

Animals↗

PubMed2005

RASSF1A gene promoter methylation in esophageal cancer specimens.

SUMMARY. RASSF1A is frequently inactivated by promoter methylation in human cancers. To understand the involvement of the RASSF1A gene in esophageal squamous cell cancer (ESCC), we investigated the methylation of the RASSF1A gene in primary ESCC to define the frequency of this epigenetic aberration and its clinicopathological significance. Methylation-specific polymerase chain reaction (MSP) was used to detect RASSF1A gene methylation in DNA from 55 cases of ESCC. Methylation of the RASSF1A gene was found in 13 of 55 (24%) cases of primary ESCC. No association was found between the promoter methylation of the RASSF1A gene in primary ESCC and age, gender, localization, invasion depth, or tumor stage. Association was found with tumor differentiation. There was no correlation with its prognosis. In conclusion, it was suggested that an inactivation of the RASSF1A gene due to promoter methylation was associated with de-differentiation of the tumor in ESCC.

Age Factors↗

PubMed2005

Anode glow discharge plasma treatment of titanium plates facilitates adsorption of extracellular matrix proteins to the plates.

Glow discharge plasma (GDP) supplied to an anode (GDP+) promotes calcium phosphate adsorption onto titanium better than that supplied to a cathode (GDP-). However, the adsorption of extracellular matrix (ECM) proteins is crucial for cell adhesion to titanium. Since GDP+ induced both inorganic adsorption and cell adhesion, we hypothesized that the inorganic adsorption in a culture medium might affect the adsorption of the ECM proteins. In this study, ECM proteins adsorbed on titanium with and without GDP were examined by x-ray photoelectron spectroscopy. After 1 hr of incubation, increasing sodium adsorption on GDP+ specimens induced adsorption of ECM proteins as shown by NH(+) and COO(-) signals without calcium adsorption. In contrast, since no specific adsorption of sodium on GDP-specimens was detected, GDP-did not contribute to the adsorption of ECM proteins. Thus, promotion of sodium adsorption of GDP+ was effective, at least in the initial ECM protein adsorption on a titanium surface.

Adsorption↗

PubMed2004

Optimal and effective oral dose of taurine to prolong exercise performance in rat.

The aim of this study was to determine the effective and optimum dose of taurine for exercise performance and to maintain tissue taurine concentration. Rats received a respective daily dose of 0, 20, 100, and 500 mg/kg body weight of taurine (EC and ET-1, -2, -3 groups, respectively) for two weeks, and then, were subjected to treadmill until exhaustion. The running time to exhaustion was significantly prolonged by 25% and 50% in the ET-2 and -3 groups, respectively, compared to that in the EC group accompanied with maintenance of taurine tissue concentrations. Furthermore, the oxidative glutathione per total glutathione ratio in tissues was inhibited in the ET-2 and -3 groups whereas it was higher in the EC group than in both the no exercise and taurine-administered groups. Therefore the effective and optimal doses of oral taurine administration for two weeks on a transient exercise performance were between 100 and 500 mg/kg/day.

Administration, Oral↗

PubMed2004

An immunohistochemical study of TIMP-3 expression in oesophageal squamous cell carcinoma.

Tissue inhibitor of metalloproteinase-3 (TIMP-3) inhibits the activity of matrix metalloproteinase, which may play an important role in carcinoma invasion and metastasis. We have investigated the relationship between TIMP-3 reduction and clinicopathological factors in oesophageal squamous cell carcinoma (ESCC). We examined tissue specimens that had been removed from 90 patients with thoracic oesophageal cancer who had undergone surgery between 1983 and 2001. Immunohistochemical staining was performed by the standard streptavidin-biotin method. Immunostaining of TIMP-3 was seen in the cytoplasm of cancer cells and normal oesophageal epithelial cells, particularly in cells located in shallow areas of the tumour. TIMP-3 preserved (+), moderate (+/-), and reduced (-) cases accounted for 30, 27, and 33 of the 90 patients, respectively (33, 30, 37%). Significant correlations were observed between TIMP-3 expression and depth of tumour invasion (P=0.001), number of lymph node metastases (P=0.003), infiltrative growth pattern (P=0.003), and disease stage (P=0.005). The survival rates of patients with TIMP-3 (-) cancer were significantly lower than those of patients with TIMP-3 (+) and TIMP-3 (+/-) cancer (P=0.0003). The mean 5-year survival rates of patients with TIMP-3 (+), (+/-), and (-) were 50, 58, and 21%, respectively. In conclusion, decreased expression of TIMP-3 protein correlates with invasive activity and metastasis. This makes the prognosis for patients with cancer that has lost TIMP-3 significantly less favourable than that for patients with cancer that has maintained TIMP-3.

Adult↗

PubMed2004

Atomic force algorithms in density functional theory electronic-structure techniques based on local orbitals.

Electronic structure methods based on density-functional theory, pseudopotentials, and local-orbital basis sets offer a hierarchy of techniques for modeling complex condensed-matter systems with a wide range of precisions and computational speeds. We analyze the relationships between the algorithms for atomic forces in this hierarchy of techniques, going from empirical tight-binding through ab initio tight-binding to full ab initio. The analysis gives a unified overview of the force algorithms as applied within techniques based either on diagonalization or on linear-scaling approaches. The use of these force algorithms is illustrated by practical calculations with the CONQUEST code, in which different techniques in the hierarchy are applied in a concerted manner.

Journal Article↗

PubMed2004

Contraction and reexpansion of polymer thin films.

We report x-ray reflectivity measurements on polystyrene thin films supported on silicon wafer. In annealing experiments, we found fast and slow contraction processes in the thin films above the glass transition temperature. The former is the normal relaxation (annealing) process observed in bulk, and the latter is unexpected and enhanced in thin films below approximately 20 nm. In addition, we found unexpected extremely slow reexpansion processes in the glassy state. These unexpected very slow processes are discussed in terms of lateral contraction and expansion processes driven by entropic changes at the interfaces and the difference of the expansivities between polystyrene and silicon wafer.

Journal Article↗