Rapid diagnosis of drug intoxication using novel NAGINATA gas chromatography/mass spectrometry software

In Japan, not only the classical stimulant, methamphetamine, but also a wide variety of illicit drugs and designer drugs are abused by juveniles. It is, however, difficult to screen these drugs in human urine due to the poor availability of high-quality standards. Therefore, it is important to develop a screening method that does not require the use of standard compounds. Furthermore, if we can obtain approximate drug concentrations in biological fluids by the first screening procedure, the subsequent treatment of the patient and forensic diagnosis can be carried out more rapidly and exact quantitative analysis performed more efficiently. We have devised a rapid screening method for the simultaneous semi-quantitative analysis of 30 abused drugs using gas chromatography/mass spectrometry (GC/MS) with a retention time locking technique. Based on this method, an 'abused drugs database' was constructed including retention time (RT), qualifier ion/target ion (QT) percentage and calibration curve (values of slope and intercept) using the novel GC/MS software, NAGINATA. We compared the analytical results obtained by this method using the constructed database with those from conventional methods in six forensic cases. The number of confirmed drugs and concentrations obtained by the established method was comparable with that obtained by conventional methods. We found a significant improvement in the time for data analysis, and qualitative and quantitative information about each drug was obtained without using standards. Therefore, this new screening procedure using NAGINATA has potential for the rapid identification of poisoning and should be useful in clinical and forensic toxicological analyses.     

Development of tubulin-polymerization inhibitors based on the thalidomide skeleton

We synthesized a series of compounds based on the potent tubulin-polymerization inhibitor 5-hydroxy-2-(2,6-diisopropylphenyl)-1H-isoindole-1,3-dione [5HPP-33 (3)], which is structurally derived from thalidomide (1), and investigated their inhibitory effects on tubulin polymerization. Direct interaction between 5HPP-33 (3) and alpha,beta-tubulin heterodimer protein was demonstrated by means of a surface plasmon resonance study.     

Density control of poly(ethylene glycol) layer to regulate cellular attachment

A wide variety of cells usually integrate and respond to the microscale environment, such as soluble protein factors, extracellular matrix proteins, and contacts with neighboring cells. To gain insight into cellular microenvironment design, we investigated two-dimensional microarray formation of endothelial cells on a micropatterned poly(ethylene glycol) (PEG)-brushed surface, based on the relationship between PEG chain density and cellular attachment. The patterned substrates consisted of two regions: the PEG surface that acts as a cell-resistant layer and the exposed substrate surface that promotes protein or cell adsorption. A PEG-brushed layer was constructed on a gold substrate using PEG with a mercapto group at the end of the chain. The density of the PEG-brushed layer increased substantially with repetitive adsorption/rinse cycles of PEG on the gold substrate, allowing marked reduction of nonspecific protein adsorption. These repeated adsorption/rinse cycles were further regulated by using longer (5 kDa) and shorter (2 kDa) PEG to construct PEG layers with different chain density, and subsequent micropatterning was achieved by plasma etching through a micropatterned metal mask. The effects of PEG chain density on pattern formation of cell attachment were determined on micropatterning of endothelial cells. The results indicated that cell pattern formation was strongly dependent on the PEG chain density and on the extent of protein adsorption. Notably, a PEG chain density high enough to inhibit outgrowth of endothelial cells from the cell-adhering region in the horizontal direction could be obtained only by employing formation of a short filler layer of PEG in the preconstructed longer PEG-brushed layer, which prevented nonspecific protein adsorption almost completely. In this way, a completely micropatterned array of endothelial cells with long-term viability was obtained. This clearly indicated the importance of a short underbrushed PEG layer in minimizing nonspecific protein adsorption for long-term maintenance of the active cell pattern. The strategy for cell patterning presented here can be employed in tissue engineering to study cell-cell and cell-surface interactions. It is also applicable for high-throughput screening and clinical diagnostics, as well as interfacing cellular and microfabricated components of biomedical microsystems.     

An approach for a synthesis of asparagine-linked sialylglycopeptides having intact and homogeneous complex-type undecadisialyloligosaccharides

This paper describes synthesis of asparagine-linked sialylglycopeptides. The typical feature of our strategy for the synthesis of a sialylglycopeptide is to employ undecadisialyloligosaccharyl Fmoc-asparagine (Fmoc-Asn(CHO)-OH) 1 without protecting groups on its hydroxyl groups except for the benzyl ester of the NeuAc residues. Our synthetic methodology solved the problem of esterification toward sugar hydroxyl groups by activated amino acids during the elongation of a peptide chain. When employing high concentrations of the Fmoc-amino acid, esterification markedly occurred, but the esterification scarcely occurred when employing low concentrations of reactants. Taking advantage of these findings, we examined the synthesis of a high molecular sialylglycopeptide, CTLA-4 fragment (113-150) 13 having two complex-type sialyloligosaccharides by use of native chemical ligation (NCL). As a result, we succeeded in the synthesis of a sialylglycopeptide having a cysteine residue at the N-terminus (CTLA-4: 129-150 fragment) 11 and a sialylglycopeptide-thioester (CTLA-4: 113-128 fragment) 12. Finally, the sialylglycopeptides synthesized were applied to NCL reactions. The reaction successfully afforded the desired product, CTLA-4 (113-150) 13 containing mature and pure complex-type sialyloligosaccharides in excellent purity.     

Construction of a small-molecule-integrated semisynthetic split intein for in vivo protein ligation

A new split intein-based protein ligation tool that is synthetically accessible and can be used for protein semisynthesis on the cell surface and potentially inside cells has been constructed.     

Lewis acid catalyzed benzylic C-H bond functionalization of azaarenes: addition to enones

A Lewis acid catalyzed benzylic C-H bond functionalization of alkyl-substituted azaarenes is described. Sc(OTf)(3) and Y(OTf)(3) promoted the direct addition of alkyl-substituted azaarenes and benzoxazole to enones and an α,β-unsaturated N-acylpyrrole. Products were obtained in 60-96% yield.     

Highly diastereoselective Claisen rearrangement leading to vicinal quaternary carbons construction of oxindoles

An efficient approach to spirocyclic oxindole architecture with vicinal quaternary carbon centers is described. The reaction of 2-allyloxyindolin-3-ones with cyanomethylphosphonate at low reaction temperature proceeds smoothly with consecutive olefination, isomerization, deacylation, and anion-accelerated Claisen rearrangement to give the 3,3-disubstituted oxindoles with vicinal quaternary all-carbon centers in high yield and diastereoselectivity. The oxindoles are readily converted into more synthetically advanced spiro-products.     

Elongation of phenoxide C-O bonds due to formation of multifold hydrogen bonds: statistical, experimental, and theoretical studies

Statistical studies using the Cambridge Structural Database have revealed that there are several elongated phenoxide C-O bonds. They are characterized by the formation of 3-fold (or occasionally 2-fold) hydrogen bonds to the phenoxide oxygen atoms, and their mean bond length extends up to 1.320 ?, which is quite different from the theoretically predicted carbon-oxygen bond length of C(6)H(5)O(-) (1.26 ?). Elongated phenoxide C-O bonds associated with the formation of 3-fold hydrogen bonds were also observed in the X-ray structures of proton-transfer complexes (2X-O(-))(TEAH(+))s derived from 5'-X-substituted 5,5'-dimethyl-1,1':3',1'-terphenyl-2,2',2'-triols (2X-OHs, where X = NO(2), CN, COOCH(3), Cl, F, H, and CH(3)) and triethylamine (TEA). By comparing the X-ray structures, C-O bond elongation was found to be only slightly affected by an electron-withdrawing substituent at the para position (X). This along with strong bathochromic shifts of N-H(···O(-)) and O-H(···O(-)) stretching vibrations in the IR spectra indicates that the elongated C-O bonds in (2X-O(-))(TEAH(+))s essentially have single-bond character. This is further confirmed by molecular orbital calculations on a model complex, showing that the negatively charged phenoxide oxygen atom is no longer conjugated to the central benzene ring, and the NICS values of the three benzene rings are virtually identical. However, C-O bond elongation in (2X-O(-))(TEAH(+))s was considerably influenced by a change in the hydrogen-bond geometry. This also suggests that hydrogen bonds significantly affect phenoxide C-O bond elongation.     

Second harmonic generation in ferroelectric liquid crystals and their mixtures

Abstract

The second harmonic generation (SHG) in the ferroelectric liquid crystal (FLC) state has been studied as functions of electric field strength, rotating angle, temperature and molecular structure. It has been confirmed that a sharp angularly phase-matching curve of the SHG controlled by an electric field is observed even in the liquid crystal. The temperature dependences of the phase-matched SHG and Maker fringe in the ferroelectric phase have also been studied, and temperature dependences of non-linear optical coefficients obtained. The SHG in several kinds of FLC and dye doped FLC have also been measured, and the enhancement of SHG realized by means of doping the FLC with several kinds of dye.