Vanillin and sulfuric acid used in a colorimetric assay of ginsenosides (saponins in the root of Panax ginseng C. A. MEYER) were directly applied to several sapogenins (Tables I1 and Ill), and their glycosides, and related compounds (Table I) without any modifications of the reaction conditions. Steroidal sapogenins with or without double bond at C-5, triterpenoid sapogenins, sterols and bile acids which have an OH group at their C-3 position, gave chromogens with the reagents. Cholanic acid (no OH group) and corticosteroids (A4-3-keto and 20,21-ketol) did not give the typical red-purple color after the treatment with the reagents. When a C-3-OH group of a sapogenin was free, bound with sugar, or esterified with acetic acid, its sapogenin moiety showed almost identical absorption propkrties after the color reaction. Every spirostane sapogenin tested gave two visible absorption maxima, one of them located around the 455 to 460 n m region. Spirostane-2, 3-diol and spirostane-l,2,3-trio1 showed atypical absorption spectra. Triterpenoid sapogenins with the C-23-OH group had an additional peak located around the 460 to 485 n m region. An OH group and a carbon-carbon double bond in rings B, C and D also seemed to affect the absorption properties due to C-3-OH in some cases. The colorimetric determination rriethod for saponins, especially triterpenoid saponins, as a simple, rapid and reasonably precise method, has been in demand for evaluation of saponin drugs and their preparations. There are many color reactions for detection of steroidal sapogenins, but few for triterpenoid sapogenins and saponins in general [I]. As for quantitative determinations by chrornogenic reaction, perchloric acid for diosgenin [Z], aromatic aldehydes-phosphoric acid for several steroidal sapogenins [3], antimony trichloride-HC1 for sapogenins in Dioscorea tubers [4], vanillin-sulfuric acid for glycyrrhetinic acid [5] aqd for senegin and sapoalbin [ 6 ] , cobaltous chloride-sulfuric acid [7] and ferric chloridesulfuric acid [8] for escin have been reported, so far as we know. These reagents are not specific for sapogenin; and can react with sterols, bile acids, steroids and terpenes which are not easily separated from sapogenins [I and 91. So we have to separate sapogenins as saponins from those compounds and then to hydrolyse the saponins.

Signal transduction and activator of transcription 3(STAT3) signaling is constitutively activated in various tumors, and is involved in cell survival and proliferation during oncogenesis. There are few reports, however, on the role of STAT3 signaling in gastric cancer. The aim of the present study was to clarify the role of STAT3 signaling in apoptosis and cellular proliferation in gastric cancer. Here we reported that STAT3 was constitutively activated in various human gastric cancer cells and its inhibition by ectopic dominant-negative STAT3 or Janus kinase inhibitor, tyrphostin AG490, induced apoptosis. Furthermore, STAT3 inhibition markedly decreased survivin expression, and forced expression of survivin rescued AGS cells from apoptosis induced by STAT3 inhibition. Although some reports demonstrated that the PI3K/Akt pathway regulates survivin expression, inhibition of the PI3K/Akt pathway did not affect survivin expression in AGS and MKN1 cells. Finally, activated form of STAT3, Tyr-705 phospho-stat3, was found in the nucleus of cancer cells in 11 of 40 (27.5%) human gastric cancer specimens. These findings suggest that constitutively activated STAT3 signaling supports gastric cancer cell survival in association with survivin expression.

High-density nickel-dispersed-alumina (Al 2 O 3 /nickel) com-or continuous phases. [24][25][26] In general, the dispersion of soft posites with superior mechanical properties were obtained metal in a ceramic has been found to have a negative effect by the hydrogen reduction and the hot pressing of aluminaon the strength of the composite, although Tuan et al. 28 have nickel oxide (Al 2 O 3 /NiO) mixed powders. The mixtures were demonstrated the strengthening of Al 2 O 3 due to microstructural prepared by using NiO or nickel nitrate (Ni(NO 3 ) 2 ؒnH 2 O) as refinement by dispersing fine nickel particles (ϳ0.5 m) in the a dispersion source of nickel metal. Microstructural invesmatrix. The latter result suggests that the strength enhancement tigations of the composite fabricated using nitrate powder may be achieved in the Al 2 O 3 /nickel "nanocomposite" system. revealed that fine nickel particles, }100 nm in diameter,Considering the magnetic properties of the composites, it is dispersed homogeneously at the matrix grain boundaries, expected that the ferromagnetism of nickel will be demonforming the intergranular nanocomposite. High strength strated by incorporating merely nanometer-sized nickel into an (.1 GPa) and high-temperature hardness were registered Al 2 O 3 ceramic. Fine particulate magnetic materials are already for the composite that contained a small amount of nickel known to exhibit a high magnetic coercive force, because of dispersion. The ferromagnetic properties of nickel, such their magnetic single-domain structure when the crystalline size as high coercive force, were observed, because of the fine becomes very small. 29-31 Magnetization of nanometer-sized iron magnetic dispersions, which indicates a functional value of in Al 2 O 3 may increase when modifying the electronic structure structural composites.of iron atoms at the particle surface, 32,33 which implies the feasibility of a synergetic combination of improved mechanical properties and excellent functionality in ceramic-metal systems