Effect of sodium tauroursodeoxycholate (UR-906) on liver dysfunction in bile duct-ligated rats

We investigated the effect of sodium tauroursodeoxycholate (UR-906) on cholestasis in common bile duct-ligated rats in comparison with the effect of dehydrocholic acid. UR-906 (30-180 mumol/kg) and dehydrocholic acid (180 mumol/kg) were intravenously given once daily for consecutive 20 days in rats and the common bile duct was ligated for the last 10 days. On the next day after the last test drug administration, serum biochemical and plasma hemostatic variables were determined. UR-906 significantly ameliorated the elevation of serum cholesterol, phospholipid, bilirubin and bile acid concentrations in bile duct-ligated rats. UR-906 significantly suppressed the prolongation of plasma prothrombin time and activated partial thromboplastin time. Furthermore, UR-906 significantly suppressed the decreases in plasma coagulation factor II and X activities. However, dehydrocholic acid did not cause significant changes in any of the variables examined in this model. These results suggest that UR-906 has a beneficial effect against cholestasis induced by bile duct ligation in rats and that this drug may be useful in the treatment of clinical cholestatic disorders.     

Direct production of ultra-fine nitrides (Si3N4 and AIN) and carbides (SiC,WC and TiC) powders by the arc plasma method

A direct method of producing ultra-fine nitride and carbide powders of 20 to 40 nm by arc plasma in a controlled atmosphere (with ammonia or methane gas) is described. The powders produced were SiC, TiC, WC (+W₂C), AIN and Si₃N₄. Other nitrides and carbides may also be produced using this method. Special attention was paid to the production conditions of silicon nitride.     

Dibutyryl cAMP inhibits endotoxin-induced increases in pulmonary vascular resistance and fluid filtration coefficient in the perfused rat lung

We investigated the effects of pre-treatment with dibutyryl cAMP (db-cAMP) or cGMP on endotoxin-induced hemodynamic changes and pulmonary vascular permeability in isolated perfused rat lungs. Intraperitoneal injection of Salmonella enteritidis endotoxin (2 mg/kg) caused increases in pulmonary arterial resistance (Ra) after venous reservoir elevation, in pulmonary filtration coefficient (Kf) and in lung wet-to-dry (W/D) weight ratio. Pre-treatment with db-cAMP blocked endotoxin-induced increases in Ra, Kf and W/D weight ratio. Pre-treatment with cGMP attenuated only the increase in Ra caused by endotoxin. Moreover, administration of db-cAMP 2 hours after endotoxin injection attenuated the increase in Ra induced by endotoxin treatment. The increases in Kf and W/D weight ratio caused by endotoxin were not affected by post-treatment with db-cAMP. Since the increases in Ra, Kf and W/D weight ratio caused by endotoxin were blocked by pre-treatment with db-cAMP, agents that increase intracellular cAMP level may be useful to prevent acute pulmonary vascular injury.     

Proposal of a new folded comb-line filter

We propose a new type of comb-line filter that is suitable for miniaturization utilizing stratifying technology. It consists of a couple of composite resonators. Each resonator is composed of two sections of a microstrip and a coplanar waveguide fabricated on the microstrip ground plane which are connected through a piece of wire at an open end to set up a new folded comb-line filter. The filtering characteristics are investigated through experiments as well as numerical simulations by means of the FD-TD method. It is shown that the filtering characteristics can be much improved by removing part of the barrier in the coplanar-line portion of the resonator to alter the coupling.     

The efficiency of helical strakes for the suppression of vortex-excited oscillation of steel stacks

Helical strikes are well known as a device to suppress the vortex-excited oscillation of stacks and have been applied to some stacks to prevent the oscillation. Wind tunnel experiments on two-dimensional models were performed to reconsider the optimum configuration of the strakes. Based on the model experimental results, the effectiveness of the strakes was confirmed by experiments on an actual stack. Finally, the stack with strakes was shown to be more economical than the plain stack without strakes.     

Surface oxide structures on a commercial activated carbon

Direct transmission IR spectra of a commercial activated carbon (Filtrasorb 200, Calgon Corporation) as well as spectra of this carbon after neutralization with 0.25 N solutions of NaOH and HCl are presented. Neutralization capacities for bases of different strengths (NaHCO₃, Na₂C0₃ and NaOH) indicate that the majority of the acidic surface groups (65%) are of weak acidity. This carbon adsorbs acid as well. From the analysis of the spectra it is concluded that the main oxides present on the surface of this particular carbon are lactones, quinones, phenols and carboxylates. The lactonic structures open upon reaction with alkali to give carboxylate structures, and in acid media the carboxylic tautomer is favored. Furthermore upon reaction with acid some of the oxides come off as C0₂. This C0₂ chemisorbs on the carbon surface and generates stable carbonate structures.     

A very small dielectric planar filter for portable telephones

A high performance, high-dielectric stripline filter with the size of 4.5 mm×3.2 mm×2.0 mm has been developed. The filter consists of planar resonators and its structure is made of high permittivity multilayer ceramic in the Bi-Ca-Nb-O system. The performance is distinctive with its attenuation pole. An equivalent lumped circuit is derived to explain the behavior of the attenuation pole quantitatively. A precise design procedure is also described     

Activation of Rho-dependent cell spreading and focal adhesion biogenesis by the v-Crk adaptor protein

The small GTPase RhoA plays a critical role in signaling pathways activated by serum-derived factors, such as lysophosphatidic acid (LPA), including the formation of stress fibers in fibroblasts and neurite retraction and rounding of soma in neuronal cells. Previously, we have shown that ectopic expression of v-Crk, an SH2/SH3 domain-containing adapter proteins, in PC12 cells potentiates nerve growth factor (NGF)-induced neurite outgrowth and promotes the survival of cells when NGF is withdrawn. In the present study we show that, when cultured in 15% serum or lysophosphatidic acid-containing medium, the majority of v-Crk-expressing PC12 cells (v-CrkPC12 cells) display a flattened phenotype with broad lamellipodia and are refractory to NGF-induced neurite outgrowth unless serum is withdrawn. v-Crk-mediated cell flattening is inhibited by treatment of cells with C3 toxin or by mutation in the Crk SH2 or SH3 domain. Transient cotransfection of 293T cells with expression plasmids for p160ROCK (Rho-associated coiled-coil-containing kinase) and v-Crk, but not SH2 or SH3 mutants of v-Crk, results in hyperactivation of p160ROCK. Moreover, the level of phosphatidylinositol-4,5-bisphosphate is increased in v-CrkPC12 cells compared to the levels in mutant v-Crk-expressing cells or wild-type cells, consistent with PI(4)P5 kinase being a downstream target for Rho. Expression of v-Crk in PC12 cells does not result in activation of Rac- or Cdc42-dependent kinases PAK and S6 kinase, demonstrating specificity for Rho. In contrast to native PC12 cells, in which focal adhesions and actin stress fibers are not observed, immunohistochemical analysis of v-CrkPC12 cells reveals focal adhesion complexes which are formed at the periphery of the cell and are connected to actin cables. The formation of focal adhesions correlates with a concomitant upregulation in the expression of focal adhesion proteins FAK, paxillin, alpha3-integrin, and a higher-molecular-weight form of beta1-integrin. Our results indicate that v-Crk activates the Rho-signaling pathway and serves as a scaffolding protein during the assembly of focal adhesions in PC12 cells.     

Sintering of Silicon Nitride with YAIO3 Additive

Sintering of Si₃N₄ powder with the addition of a Y₂O₃+ Al₂O₃ mixture or YAlO₃ as sintering aids was investigated. Sintering was improved in the case of YAlO₃ additive compared to that for the Y₂O₃+ Al₂O₃ mixture. An initial delay in densification was most likely caused by heterogeneity of the liquid phase formed in the case of the separate oxide additions at temperatures above 1700°C.