Inhibitory Effects of 2,6-Di-O-methyl-3-O-acetyl-β-cyclodextrins with Various Degrees of Substitution of Acetyl Group on Macrophage Activation and Endotoxin Shock Induced by Lipopolysaccharide

The effects of 2,6-di-O-methyl-3-O-acetyl-β-cyclodextrins (DMA-β-CyD) with various degrees of substitution (DS) of an acetyl group of 1.5, 3.8, 6.3 and 7, which are abbreviated to DMA2-β-CyD, DMA4-β-CyD, DMA6-β-CyD and DMA7-β-CyD, respectively, on murine macrophage activation and endotoxin shock induced by lipopolysaccharide (LPS) were examined. Of four DMA-β-CyDs used in the present study, cytotoxicity of DMA-β-CyDs in RAW264.7 cells, a murine macrophage-like cell line, decreased with an increase in the DS values of DMA-β-CyD, and DMA7-β-CyD had no cytotoxicity on RAW264.7 cells up to 100 mM. DMA2-β-CyD and DMA7-β-CyD at the concentration of 5 mM had greater inhibitory effects on nitric oxide (NO) production in RAW264.7 cells stimulated with LPS than DMA4-β-CyD and DMA6-β-CyD. In addition, these inhibitory effects of DMA2-β-CyD and DMA7-β-CyD were concentration-dependent. In the in vivo study, all of the mice died within 12 h after intraperitoneal administration of the solution containing LPS and d-galactosamine. When 100 mM DMA7-β-CyD was concomitantly administered with both LPS and d-galactosamine intraperitoneally in mice, the survival rate significantly increased, but DMA4-β-CyD and DMA6-β-CyD did not. In conclusion, we revealed that DS values of DMA-β-CyDs strikingly affect not only the cytotoxic activity but also the inhibitory effects of LPS-induced NO production in RAW264.7 cells and fatality of endotoxin shock mice induced by LPS and d-galactosamine. These results suggest the potential use of DMA7-β-CyD as an antagonist of LPS-induced endotoxin shock.     

Formation mechanism of an “onionlike” multilayered structure by reconstruction of the morphology of micron-sized,monodisperse poly(methyl methacrylate)/polystyrene composite particles with the solvent-absorbing/solvent-releasing method

The formation mechanism of the onionlike multilayered morphology of micron-sized, monodisperse poly(methyl methacrylate) (PMMA)/polystyrene (PS) (1/1 w/w) composite particles by the solvent-absorbing/solvent-releasing method was discussed. It was concluded that the orientation of PMMA components at the outer interface of toluene-swollen particles with water is the trigger and that PMMA-g-PS operates to stabilize inner multilayer interfaces for the formation of the onionlike multilayered morphology.Part CCLV of the series Studies on suspension and emulsion     

Assessment of provitamin A determination by open column chromatography/visible absorption spectrophotometry

Determination of provitamin A content by open column chromatography/visible absorption spectrophotometry is assessed using food samples of varying carotenoid composition. A general method consisting of extraction with acetone, transfer to petroleum ether, saponification (optional), concentration, separation on activated MgO:Hyflo Supercel column developed with 1 to 15% acetone in petroleum ether, and quantitation of individual provitamins spectrophotometrically demonstrates repeatability comparable with that of high-performance liquid chromatographic (HPLC) methods. Overnight saponification (10% methanolic KOH, ambient temperature) does not degrade the provitamins and is unnecessary for kale, tomato, and squash; however, it is required for good separation of papaya carotenoids due to the presence of carotenol esters. The current Association of Official Analytical Chemists (AOAC) method is found to be inappropriate because (1) the volume of extracting solvent is not adjusted to the type of sample; (2) the less active alpha- and gamma-carotene, alpha- and beta-cryptoxanthin, and 5,6-monoepoxy-beta-cryptoxanthin (50% active) are quantified as beta-carotene (100% active); (3) inactive carotenoids such as xi-carotene and zeinoxanthin are also quantified as beta-carotene.     

Effect of graft polymer on the formation of micron-sized,monodisperse, "onion-like" alternately multilayered poly(methyl methacrylate)/polystyrene composite particles by reconstruction of morphology with the solvent-absorbing/releasing method

Some factors contributing to the formation of an alternately multilayered structure of micron-sized, monodisperse poly(methyl methacrylate) (PMMA)/polystyrene (PS) (1/1, w/w) composite particles by reconstruction of the morphology with the solvent-absorbing/releasing method (SARM) were discussed. The original composite particles, which were produced by seeded dispersion polymerization (SDP) of styrene, had a core–shell structure. When PS/PMMA (1/1, w/w) composite particles produced by SDP of methyl methacrylate were treated by the SARM with toluene, the reconstructed morphology of the composite particles was not the multilayered structure but a hemisphere (or core–shell). The PS/PMMA composite particle contained less than 10 wt% PMMA- g-PS. On the other hand, the PMMA/PS composite particles contained about 40 wt% graft polymer. The graft polymer would exist at the interfaces of the alternate multilayers and decrease their interfacial energy. This was the main reason why the alternately multilayered structure was constructed by the SARM, though the total interfacial area between PMMA and PS layers in the multilayered particle is much larger than that of the hemisphere (or core–shell).     

Picosecond IR-UV pump-probe spectroscopic study on the intramolecular vibrational energy redistribution of NH2 and CH stretching vibrations of jet-cooled aniline

Intramolecular vibrational energy redistribution (IVR) of the NH2 symmetric and asymmetric stretching vibrations of jet-cooled aniline has been investigated by picosecond time-resolved IR-UV pump-probe spectroscopy. A picosecond IR laser pulse excited the NH2 symmetric or asymmetric stretching vibration of aniline in the electronic ground state and the subsequent time evolutions of the excited level as well as redistributed levels were observed by a picosecond UV pulse. The IVR lifetimes for symmetric and asymmetric stretches were obtained to be 18 and 34 ps, respectively. In addition, we obtained the direct evidence that IVR proceeds via two-step bath states; that is, the NH2 stretch energy first flows into the doorway state and the energy is further dissipated into dense bath states. The rate constants of the second step were estimated to be comparable to or slower than those of the first step IVR. The relaxation behavior was compared with that of IVR of the OH stretching vibration of phenol [Y. Yamada, T. Ebata, M. Kayano, and M. Mikami J. Chem. Phys. 120, 7400 (2004)]. We found that the second step IVR process of aniline is much slower than that of phenol, suggesting a large difference of the "doorway state increasing the dense bath states" anharmonic coupling strength between the two molecules. We also observed IVR of the CH stretching vibrations, which showed much faster IVR behavior than that of the NH2 stretches. The fast relaxation is described by the interference effect, which is caused by the coherent excitation of the quasistationary states.     

First observation of a dihydrogen bond involving the Si-H group in phenol-diethylmethylsilane clusters by infrared-ultraviolet double-resonance spectroscopy

We have experimentally identified a dihydrogen bond involving the Si-H group in phenol-diethylmethylsilane (DEMS) clusters for the first time by IR-UV double-resonance spectroscopy. Vibrational shifts to lower frequency of 21-29 cm(-1) were found for the OH stretching vibration of three isomers of the phenol-DEMS clusters. Spectral simulations based on the MP2 calculations also support our observation. In addition to these clusters, dihydrogen bonds were also observed in the phenol-H(2)O-DEMS and (phenol)(2)-DEMS clusters, which exhibited much stronger interactions than the phenol-DEMS clusters.     

Tetradecyldimethylbenzylammonium thiocyanate adsorbent supported on naphthalene for the preconcentration and determination of cobalt in aluminium alloys and steels using atomic absorption spectrometry

A solid ion-pair material produced from tetradecyldimethylbenzylammonium chloride (TDBA) and ammonium thiocyanate on naphthalene provides a simple, rapid and selective technique of preconcentrating cobalt from up to 200 ml of aqueous solution. Cobalt reacts with sodium 1-nitroso-2-naphthol-3,6-disulphonate (nitroso-R salt) to form a brown, water-soluble chelate anion. The chelate anion forms a water-insoluble Co-nitroso-R salt-TDBA complex on naphthalene packed in a column and trace cobalt is quantitatively retained on the naphthalene in the pH range 2.7–11.0 at a flow-rate of 2 ml min^?1. The solid mass is stripped from the column with 5 ml of dimethylformamide (DMF) and cobalt is measured by atomic absorption spectrometry (AAS) at 241 nm. The calibration graph is linear over the concentration range 0.5–15μg Co in 5 ml of dimethylformamide solution. Seven replicate determinations of 9 μg of cobalt gave a mean absorbance of 0.095 with a relative standard deviation of 1.7%. The sensitivity for 1% absorption was 0.0834μg ml^?1 (0.240 μg ml^?1 for direct AAS on the aqueous solution). The proposed method was utilized for the determination of cobalt in standard aluminium alloys and steel samples.