Tissue biocompatibility of cellulose and its derivatives was examined in two in vivo tests, one for absorbance by living tissue and one for foreign body reaction. The samples examined were regenerated celluloses and cellulose derivatives: methyl cellulose, ethyl cellulose, aminoethyl cellulose, hydroxyethyl cellulose, and cellulosic polyion complexes. The in vivo absorbance by living tissue was found to depend on the degree of crystallinity and the chemical structure of the sample. The foreign body reaction was relatively mild for all the samples examined, showing that cellulose can be converted to biocompatible materials by physical and/or chemical transformation.

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We investigated the inhibitory role of the nitric oxide (NO)-cGMP-protein kinase G (PKG) pathway on receptor-activated TRPC6 channels in both a heterologous expression system (HEK293 cells) and A7r5 vascular myocytes. Cationic currents due to TRPC6 expression were strongly suppressed (by ∼70%) by a NO donor SNAP (100 μm) whether it was applied prior to muscarinic receptor stimulation with carbachol (CCh; 100 μm) or after G-protein activation with intracellular perfusion of GTPγS (100 μm). A similar extent of suppression was also observed with a membrane-permeable analogue of cGMP, 8Br-cGMP (100 μm). The inhibitory effects of SNAP and 8Br-cGMP on TRPC6 channel currents were strongly attenuated by the presence of inhibitors for guanylyl cyclase and PKG such as ODQ, KT5823 and DT3. Alanine substitution for the PKG phosphorylation candidate site at T69 but not at other sites (T14A, S28A, T193A, S321A) of TRPC6 similarly attenuated the inhibitory effects of SNAP and 8Br-cGMP. SNAP also significantly reduced single TRPC6 channel activity recorded in the inside-out configuration in a PKG-dependent manner. SNAP-induced PKG activation stimulated the incorporation of 32 P into wild-type and S321A-mutant TRPC6 proteins immunoprecipitated by TRPC6-specific antibody, but this was greatly attenuated in the T69A mutant. SNAP or 8Br-cGMP strongly suppressed TRPC6-like cation currents and membrane depolarization evoked by Arg 8 -vasopressin in A7r5 myocytes. These results strongly suggest that TRPC6 channels can be negatively regulated by the NO-cGMP-PKG pathway, probably via T69 phosphorylation of the N-terminal. This mechanism may be physiologically important in vascular tissues where NO is constantly released from vascular endothelial cells or nitrergic nerves.

To understand the formation process of the microstructure of the catalyst layer of a polymer electrolyte fuel cell (PEFC), we tried to observe the “real” structure of the catalyst ink by cryogenic scanning electron microscopy (cryo‐SEM). Catalyst inks with different water/alcohol compositions were successfully visualized, and they correlated well with the particle‐size distribution obtained by laser diffraction of the ink and the structures of the catalyst layers obtained by typical SEM. On the basis of other electrochemical characterization results, including current–voltage performance, oxygen reduction reaction kinetics, and mass‐transport properties, the microstructures of the catalyst inks and the catalyst layers were proposed. The proposed microstructures can explain the relationship between the catalyst materials and the performance of the cathode catalyst layer of the membrane electrode assembly through its formation and apparent properties. It was also found that the microstructure of the catalyst ink plays an important role in performance.