Biochemical characterization of glycyrrhizin as an effective inhibitor for hyaluronidases from bovine testis

The inhibitory effects of several anti-inflammatory agents, including glycyrrhizin (GL), on the activities of hyaluronidases (HAses) purified from bovine testes and Streptomyces were investigated in vitro. It was found that (i) GL inhibits the activity of HAse (p55) from bovine testes in a dose-dependent manner, but does not affect HAse from Streptomyces; (ii) GL was the most effective of the compounds tested on bovine testis HAse activity (50% inhibition with approx. 3 microM GL); and (iii) glycyrrhetinic acid (GA), a derivative (oGA) of GA and diglucuronic acid had no detectable effects on HAse activity at 9.0 microM. The GL-induced inhibition of HAse activity is uncompetitive for its substrates. Data are provided to support the contentions that (i) bovine testis HAse (p55) is a GL-binding protein; and (ii) GL acts as a potent inhibitor of HAse in vitro.     

Evaluation of the implant type tissue-engineered cartilage by scanning acoustic microscopy

The tissue-engineered cartilages after implantation were nonuniform tissues which were mingling with biodegradable polymers, regeneration cartilage and others. It is a hard task to evaluate the biodegradation of polymers or the maturation of regenerated tissues in the transplants by the conventional examination. Otherwise, scanning acoustic microscopy (SAM) system specially developed to measure the tissue acoustic properties at a microscopic level. In this study, we examined acoustic properties of the tissue-engineered cartilage using SAM, and discuss the usefulness of this devise in the field of tissue engineering. We administered chondrocytes/atelocollagen mixture into the scaffolds of various polymers, and transplanted the constructs in the subcutaneous areas of nude mice for 2 months. We harvested them and examined the sound speed and the attenuation in the section of each construct by the SAM. As the results, images mapping the sound speed exhibited homogenous patterns mainly colored in blue, in all the tissue-engineered cartilage constructs. Contrarily, the images of the attenuation by SAM showed the variation of color ranged between blue and red. The low attenuation area colored in red, which meant hard materials, were corresponding to the polymer remnant in the toluidine blue images. The localizations of blue were almost similar with the metachromatic areas in the histology. In conclusion, the SAM is regarded as a useful tool to provide the information on acoustic properties and their localizations in the transplants that consist of heterogeneous tissues with various components.     

Fabrication and optical properties of NUV-emitting SiO2–SrB4O7:Eu glass–ceramic thin films

SiO₂–SrB₄O₇:Eu²⁺ glass–ceramic thin films were fabricated for possible application in near ultraviolet (NUV) emitting devices. Nano-sized SrB₄O₇:Eu²⁺ powders were prepared by a Pechini-type sol–gel method and a subsequent ball-milling treatment. The powders showed NUV emissions centered at 367 nm, upon irradiation with UV of shorter wavelengths, due to an allowed 4f⁶5d¹ → 4f⁷ electronic transition of Eu²⁺ ions. The glass–ceramic thin films were prepared by dip-coating of tetraethylorthosilicate (TEOS) solutions dispersed with the nano-sized SrB₄O₇:Eu²⁺ powders and a subsequent heat-treatment. It was found that the glass–ceramic thin films had relatively high thermal stability up to 800 °C in terms of the Eu²⁺ emissions. SiO₂ layers surrounding SrB₄O₇:Eu²⁺ appeared to be effective for the surface passivation of the phosphor particles.     

Studies of electrochemical interfaces of thin PT film electrodes by surface conductance

In this paper the dc conductance of thin Pt films has been measured with respect to film thickness and to the surface effects as a function of the electrode potential in the “ideal” double layer, platinum “oxygen” and adsorbed hydrogen regions. The change in the value of dc conductance has been correlated with the electric charge as potential is scanned in these regions. Tentative mechanistic suggestions are offered to explain the data including some results on the deposition of copper on platinum.     

Serum soluble Fas/APO-1 is increased in patients with primary Sj?gren''s syndrome

The aim of the study was to elucidate the involvement of Fas antigen in human autoimmune disease, by analysing serum levels of soluble Fas/APO-1 protein in patients with various autoimmune diseases, including system lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc), polymyositis/dermatomyositis (PM/DM), Beh?et's syndrome and Sj?gren's syndrome (SjS). The levels of soluble Fas/APO-1 in sera were quantitated by a sandwich enzyme-linked immunosorbent assay. Soluble Fas/APO-1 levels were significantly increased in serum from patients with primary Sj?gren's syndrome (primary SjS) compared with control subjects. However, no significant differences in soluble Fas/APO-1 levels were noted in patients with secondary Sj?gren's syndrome (secondary SjS) nor in patients with any of the other autoimmune diseases. The soluble Fas/APO-1 level in primary SjS patients with extraglandular diseases was significantly higher than that in patients without extraglandular diseases. These results suggest that soluble Fas/APO-1 protein may play an important role in the pathogenesis of primary SS.     

Tumorigenicity study of ferric citrate administered orally to mice

Ferric citrate (FC) was orally administered at concentrations of 0.12 (maximum tolerated dose) or 0.06% in the drinking water to male and female B6C3F1 mice. Treatment was continued for 96 wk and the experiment was terminated at wk 100. There was no significant difference between treated and control groups in the tumour incidence or in the distribution of different types of tumour. Thus the long-term oral administration of FC to mice did not yield any evidence of chronic toxicity or tumorigenicity.     

Forwarding reversible photocatalytic reactions on semiconductor particles using an oil/water boundary

Photocatalytic oxidation of iodide ions and hydrogen evolution proceeded on Pt-loaded titanium dioxide particles in aqueous solutions. The reaction rate levelled off as the concentration of tri-iodide ions increased. This was due to the reduction of tri-iodide ion into iodide ion on the photocatalyst. This process is the back reaction of the energy storing photocatalytic reaction. By introducing an oil phase on the aqueous solution the back reaction was retarded, because part of the tri-iodide ions were transported to the oil phase. The back reaction was much eliminated when durohydroquinone was added to the oil phase. In this case, tri-iodide ions in aqueous solution was scavenged as the result of the redox reaction between tri-iodide ion and durohydroquinone, leading to the prevention of the back reaction. This system is comparable to the functions of photosystem I and plastoquinone in the thylakoid membrane of green plants.     

Low distortion 1.3 μm strained-layer MQW-DFB laser for AM-SCMtransmission systems with large channel capacity

1.3-μm strained-layer multiquantum-well distributed-feedback (SL-MQW-DFB) lasers with extremely low distortion and low noise characteristics up to high output-power as well as over wide frequency range were successfully fabricated. This was achieved by both the high relaxation oscillation frequency (f_r) characteristics of the laser with the optimized SL-MQW active structure and the suppression of nonradiative current with relatively long laser cavity length. By using the SL-MQW laser with a 400-μm long cavity as a light source for CATV transmission system, high quality AM-SCM transmissions with the largest channel capacity (151 channel) was demonstrated due to low distortion characteristics at high output power. Also, for the laser with 300 μm long cavity, extremely low bias-current operation (17 mA above threshold) is realized in high quality 100 channel AMSCM transmissions, due to high f_r at low bias-current