Search

Polyhydroxy stilbenes have been reported to possess various biological activities and have potential for treatment of Alzheimer's disease. Tetrahydroxystilbene glucoside is one of the major polyhydroxy stilbenes, which provides the underlying therapeutic activities for neuroprotective actions in various experimental conditions. This study investigates the impact of a tetrahydroxystilbene glucoside remedy for cognitive disorder and oxidative stress in Aβ1-42-induced Alzheimer's disease mice and clarifies the mechanisms of action through the Kelch-like erythroid cell-derived protein with conserved non-coding homology-associated protein 1/nuclear factor erythroid 2-related factor pathway. It was found that the swimming time of Aβ1-42-induced mice treated with tetrahydroxystilbene glucoside (30, 60, and 120 mg/kg) was significantly increased in the target quadrant of a Morris water maze experiment and the number of avoidances was increased during a passive avoidance experiment, Moreover, tetrahydroxystilbene glucoside attenuated Aβ1-42-induced memory impairment. However, the locomotor and exploratory activity of mice were not affected. Tetrahydroxystilbene glucoside clearly decreased the levels of malondialdehyde and oxidized glutathione in both hippocampus and cortex compared with the Aβ1-42-treated group, and also clearly increased the level of glutathione and activities of catalase and superoxide dismutase in those tissues. The results of this study demonstrated that tetrahydroxystilbene glucoside increased nuclear factor erythroid 2-related factor and heme oxygenase-1 protein expression and decreased Kelch-like erythroid cell-derived protein with conserved non-coding homology-associated protein 1 protein expression in a concentration-dependent manner in Aβ1-42-treated mice, which involved the Kelch-like erythroid cell-derived protein with conserved non-coding homology-associated protein 1/nuclear factor erythroid 2-related factor antioxidant pathway in hippocampus and cerebral cortex tissue. These results demonstrate that tetrahydroxystilbene glucoside as a natural drug that may provide a potential treatment for Alzheimer's disease.

The purpose of this paper is to derive and apply the relationships of the dynamic substructure synthesis method, based on the subregion variational principle of elastodynamics in discrete form. Two theorems are derived for discretized systems and are used to demonstrate the interface compatibility condition of dynamic substructure synthesis. This enables the dynamic substructure synthesis method to be derived from the subregion variational principle. A complete modal expansion is used to derive the residual modes for both the free and fixed interface methods. The alternative formulations of the hybrid, free interface, and fixed interface methods, as well as Guyan-Irons reduction, are shown by coordinate transformations to be degenerate cases. These cases are all reasonable representations of the Rayleigh-Ritz method, and if they use constraint modes and/or attachment modes, good convergence can be assured because the static modes are included in the substructure reduction. The relationships between these cases are explored, and illustrative examples are solved.