Total assignment of the (1)H- and (13)C-NMR spectra for TZT-1027 and related compounds

The total assignment of the (1)H- and (13)C-NMR spectra for TZT-1027 was carried out using various NMR methods (1D, 2D NMR). It was found that TZT-1027 exists in two different conformations resulting from the cis-trans isomerization of the amide bond at N-11 and C-12 in DMSO-d(6). The (1)H- and (13)C-NMR spectra of compound 1 and 2 comprised of the partial structure of TZT-1027 were also assigned to be TZT-1027. These assignments showed that compound 1 is in good agreement with TZT-1027 with regard to formation of the conformers.     

Efficient radical scavenging ability of artepillin C,a major component of Brazilian propolis,and the mechanism

Hydrogen transfer from artepillin C to cumylperoxyl radical proceeds via one-step hydrogen atom transfer rather than via electron transfer, the rate constant of which is comparable to that of (+)-catechin, indicating that artepillin C can act as an efficient antioxidant.     

Altered metabolism of bile acids in cholestasis: determination of 1 beta- and 6 alpha-hydroxylated metabolites

Trihydroxy and tetrahydroxy bile acid metabolites substituted at the C-1 or C-6 position were studied using the urine, serum and liver tissue from sixteen patients with cholestatic liver diseases. Following extraction, isolation and hydrolysis, bile acids were converted into the dimethylethylsilyl derivatives and assayed by capillary gas chromatography-mass spectrometry. Five 1 beta-hydroxylated bile acids, viz. 1 beta,3 alpha,12 alpha-trihydroxy-, 1 beta,3 alpha,7 alpha-trihydroxy-, 1 beta,3 alpha,7 beta-trihydroxy-, 1 beta,3 alpha,7 alpha,12 alpha-tetrahydroxy-5 beta-cholanoic acids and an epimer of the first compound, and two 6 alpha-hydroxylated bile acids, viz. 3 alpha,6 alpha,7 alpha-trihydroxy-, 3 alpha,6 alpha,7 alpha,12 alpha-tetrahydroxy-5 beta-cholanoic acids, were completely or partially identified. Large amounts of 1 beta-hydroxylated and 6 alpha-hydroxylated bile acids were found in the urine, whereas only trace amounts were detected in the serum and liver tissue. These findings indicate that altered metabolism, such as 1 beta- or 6 alpha-hydroxylation of bile acids, is enhanced in cholestasis, and that the resulting hydroxylated metabolites are eliminated in the urine.     

Sequence-selective DNA detection using multiple laminar streams: a novel microfluidic analysis method

On-site detection methods for DNA have been demanded in the pathophysiology field. Such analysis requires a simple and accurate method, rather than high-throughput. This report describes a novel microfluidic analysis method and its application for simple sequence-selective DNA detection. The method uses a microchannel device with a serpentine structure. Sequence-specific binding of probe DNA can be detected at one side of the microchannel. This method is capable of sequence-specific detection of DNA with high accuracy. Single base mutations can also be analyzed. Combination of laminar stream and laminar secondary flow in the microchannel enable specific detection of probe-bound DNA.     

Simultaneous determination of heavy metals in waters by inductively-coupled plasma atomic emission spectrometry after extraction into diisobutyl ketone

Nebulization of more than thirty aliphatic and aromatic liquids into a low power (<1.6 kW) argon inductively-coupled plasma (i.c.p.) was evaluated. Diisobutyl ketone (DIBK) was best owing to the ease of its introduction into the i.c.p. and low aqueous solubility. Dichloro-8-quinolinol, hexamethyleneammonium hexamethylenedithiocarbamate and ammonium pyrrolidinedithiocarbamate were tested for extraction ; the last was preferred as chelating reagent because it formed complexes with Cd, Pb, Zn, Fe, Cu, Ni, Mo and V at pH 2.4. These metals at μg l^-1 levels in river and sea water were extracted into DIBK and determined simultaneously by i.c.p. atomic emission spectrometry. The optimum observation height for the DIBK extract was higher than that for an aqueous solution.     

Recognition of liposome-bound antigens by antipeptide antibody

In order to clarify the effects of the differences in physical states of antigens on recognition by antibodies in immunoassays, the binding characteristics of an antipeptide polyclonal antibody to the peptide and the corresponding protein were studied. The reactivity in the immunoliposome assay (ILA), as well as in the double-antibody sandwich ELISA, was identical to that in the solution. These results indicate that the conformation of liposome-bound antigen is changed little by coupling to liposomes and is almost the same as that of the native antigen in the liquid phase. It is desirable to assay by double-antibody sandwich ELISA or ILA to detect native proteins, and the latter is very easily performed.     

Controllable polymerization of N-carboxy anhydrides in a microreaction system

We have developed a microfluidic system for polymerization of amino acid N-carboxyanhydride and compared the properties of the products with those obtained by batchwise system under various experimental conditions. It was found that the microreactor produced polymers with narrower molecular weight distribution compared with polymers obtained by the batchwise system. Also, the molecular mass of the polymer produced using the microreactor was simply governed by the flow (pumping) rate. These results indicated that the microreactor could be a model for synthesis of amino acid polymer with highly controllable average molecular weight and molecular weight distribution.     

Polymerization of vinyl compounds with heterocyclic groups. IV. Thermal polymerization of 2-vinylthiophene

2-Vinylthiophene was found to undergo thermal polymerization. With benzene as diluent, the overall rate of polymerization was proportional to the 2.5 power of monomer concentration, suggesting that the thermal initiation is a termolecular process. The following Arrhenius equation was obtained from the polymerization data for the range 55–100°C: The activation energy of the thermal initiation was estimated to be 28.2 kcal/mole, which was similar to those values obtained for styrene and 2-vinylfuran. When a dilute solution of the monomer in bromobenzene was heated in an ampoule at 151°C, a dimer, mp 82°C, was obtained in a good yield. The spectroscopic data indicated that the dimer was a Diels-Alder type adduct. The initiation of the thermal polymerization was considered to involve hydrogen abstraction by monomer from the Diels-Alder dimer, in common with the initiation of other vinylaromatic monomers.