Cell processing on polyimide surface patterned by rubbing

In this study, we prepared a novel rubbed fluorinated polyimide film using a rubbing machine with a rubbing cloth and determined the surface properties of the rubbed film using an atomic force microscope and contact angle measurements. In addition, we evaluated the cell adhesion behavior on the rubbed polyimide film using a phase contrast microscope. Interestingly, a rubbed polyimide surface having a micrometer‐scale grooved pattern was prepared by the rubbing method, and the morphologies of rat primary hepatocytes and human liver cell lines attached to the rubbed surface were three‐dimensional multicellular spheroids, while the cells on an unrubbed surface showed two‐dimensional monolayers. This initial study indicates that the rubbing method without any chemical modification is simple and can easily produce large surface areas, suggesting that the rubbing may become a novel cell culture method. Copyright © 2008 John Wiley & Sons, Ltd.     

Efficient Transformation of Polymer Main Chain Catalyzed by Macrocycle Metal Complexes via Pseudorotaxane Intermediate

Post-synthesis modification of polymers streamlines the synthesis of functionalized polymers, but is often incomplete due to the negative polymer effects. Developing efficient polymer reactions in artificial systems thus represents a long-standing objective in the fields of polymer and material science. Here, we show unprecedented macrocycle-metal-complex-catalyzed systems for efficient polymer reaction that result in 100 % transformation of the main chain functional groups presumably via a processive mode reaction. The complete polymer reactions were confirmed in not only intramolecular reaction (hydroamination) but also intermolecular reaction (hydrosilylation) by using Pd- and Pt-macrocycle-catalyzed systems. The most fascinating feature of the both reactions is that higher-molecular-weight polymers reach completion faster. Various studies suggested that the reactions occur in the catalyst cavity via the formation of a supramolecular complex between the macrocycle catalyst and polymer substrate like pseudorotaxane, which should be of characteristic of the efficient polymer reactions progressing in a processive mode.     

Gene Delivery into T-Cells Using Ternary Complexes of DNA,Lipofectamine, and Carboxy-Terminal Phenylalanine-Modified Dendrimers

T-cells play critical roles in various immune reactions, and genetically engineered T-cells have attracted attention for the treatment of cancer and autoimmune diseases. Previously, it is shown that a polyamidoamine dendrimer of generation 4 (G4), modified with 1,2-cyclohexanedicarboxylic anhydride (CHex) and phenylalanine (Phe) (G4-CHex-Phe), is useful for delivery into T-cells and their subsets. In this study, an efficient non-viral gene delivery system is constructed using this dendrimer. Ternary complexes are prepared using different ratios of plasmid DNA, Lipofectamine, and G4-CHex-Phe. A carboxy-terminal dendrimer lacking Phe (G3.5) is used for comparison. These complexes are characterized using agarose gel electrophoresis, dynamic light scattering, and ζpotential measurements. In Jurkat cells, the ternary complex with G4-CHex-Phe at a P/COOH ratio of 1/5 shows higher transfection activity than other complexes, such as binary and ternary complexes with G3.5, without any significant cytotoxicity. The transfection efficiency of the G4-CHex-Phe ternary complexes decreases considerably in the presence of free G4-CHex-Phe and upon altering the complex preparation method. These results suggest that G4-CHex-Phe promotes the cellular internalization of the complexes, which is useful for gene delivery into T-cells.     

Discovery of New Cytotoxic Aplaminone Derivatives from the Sea Hare Aplysia kurodai and Elucidation of Their Accumulation from Local Sea Algae through the Food Chain

The shell-less herbivorous marine mollusk (sea hare) Aplysia kurodai is known to contain a variety of bioactive substances. While these compounds have been thought to originate from sea algae or their associated microbes, most of their origin and acquisition pathways are still unclear. Six new cytotoxic aplaminone derivatives, bromodopamine-terpenoid hybrid molecules, were isolated from A. kurodai. Among them, isoaplaminone had a reverse prenyl group at the C15 aliphatic chain, which is a rare structural feature from the viewpoint of terpenoid biosynthesis. Investigation for chemical components in A. kurodai and the sea algae collected at several different locations revealed that two major aplaminones were contained in the Laurencia complex species at specific sites. Our chemical and ecological studies provide new insights into the origin of marine alkaloid toxins and their dynamism through the food chain.     

Antiviral activities of glycyrrhizin and its modified compounds against human immunodeficiency virus type 1 (HIV-1) and herpes simplex virus type 1 (HSV-1) in vitro.

Chemically modified compounds of glycyrrhizin have been synthesized and evaluated for their inhibitory effect on the replication of human immunodeficiency virus type 1 (HIV-1) and herpes simplex virus type 1 (HSV-1). Among them, the 11-deoxo compound having a heteroannular diene structure at the C and D rings proved as active against HIV-1 as glycyrrhizin in MT-4 and MOLT-4 cells. It completely inhibited HIV-1-induced cytopathogenicity in both cell lines at a concentration of 0.16 mM. The compound was also effective against HSV-1 with a 50% inhibitory concentration of 0.5 mM [corrected].     

Atomic force microscope images of the surfaces of aspirin crystals at submolecular resolution.

The atomic force microscope has been developed and used to image arrays of molecules at the (001) and (100) faces of aspirin crystals in water and in air. Lattice spacings composed of methyl groups and the part of the phenyl groups on the surface of the (001) in water, are consistent with X-ray diffraction data. The surface of (100) face which shows most perfect cleavage in bulk, is more difficult to image. This initial success in imaging at drug crystal surfaces clarified the different structural behavior at the submolecular level for three crystal faces, and the close relationship to the differences in the dissolution velocity.     

Reduction of 2,3,5-trimethyl-6-(3-pyridylmethyl)-1,4-benzoquinone by PB-3c cells and biological activity of its hydroquinone

2,3,5-Trimethyl-6-(3-pyridylmethyl)-1,4-benzoquinone (CV-6504) has inhibitory activities on both thromboxane A2 synthase and 5-lipoxygenase as well as scavenging activity against active oxygen species. The latter two activities are closely related to the quinone moiety, which is reduced to a hydroquinone in the living body. Comparison of these two activities for both the quinone and hydroquinone showed that the hydroquinone form had superior activities. Concerning the reduction mechanism by PB-3c cells we can see that superoxide dismutase (SOD) has no influence on the rate of reduction, but dicumarol almost completely inhibits the reduction at a concentration greater than 1 x 10(-6) M. Therefore, it can be concluded that CV-6504 is reduced mainly by two electron donating enzymes without the intermediary of a semiquinone radical and that the resulting hydroquinone inhibits lipid peroxidation as well as 5-lipoxygenase activity.     

Permeability of glycosides through human erythrocyte membrane

The permeability of glycosides (arbutin, salicin, glycyrritin, p-nitrophenyl-beta-D-glucopyranoside, p-nitrophenyl-beta-D-galactopyranoside, p-nitrophenyl-beta-D-lactopyranoside, p-nitrophenyl-beta-D-maltopyranoside) and their aglycons through human erythrocyte membrane was investigated. The glycosides permeated slowly, compared with their aglycons. Glycoside having disaccharide did not permeate the erythrocyte membrane. This suggested that the introduction of disaccharide to a drug significantly depresses the permeability of glycoside through erythrocyte membrane. The drug entrapped in erythrocytes was not released into the outer medium.