It has been reported that ischemic preconditioning of the heart or brain has a possible relevance to heat shock protein (HSP). It is still unknown, however, whether HSP induced by means of ischemic preconditioning of the liver is a direct factor in the acquisition of tolerance to succeeding ischemia-reperfusion injury. In the present study we used ischemic preconditioning of the liver to verify the effects of induced HSP72 in the liver on the subsequent longer warm ischemia and reperfusion. Rats preconditioned with short-term (15-minute) ischemia were compared with rats preconditioned by heat exposure or with control rats. After a 48-hour recovery from the sublethal stress for preconditioning, all rats were exposed to longer (30-minute) warm ischemia and reperfusion. Forty-eight hours after ischemic preconditioning, HSP72 was clearly induced in the liver, as well as in the liver preconditioned with heat shock, but not in the kidney or heart. This ischemic preconditioning also attenuated the liver damage in the subsequent ischemia-reperfusion injury, improving the restoration of hepatic function during reperfusion and resulting in higher postischemic rat survival. According to the proposed model of tolerance acquisition for ischemia-reperfusion injury by stress preconditioning, these observations support the speculation that the induced HSP72 plays some beneficial role in this protection mechanism.

a b s t r a c tWe present a numerical analysis of gas hydrate dissociation in hydrate-bearing sediments in the seabed ground. Behavior of multiphase materials has been described within the framework of a macroscopic continuum approach through the use of the theory of porous media. The proposed simulation method has been developed based on chemo-thermo-mechanically coupled analysis, taking into account phase changes from solids to fluids, that is, water and gas, flow of water and gas, heat transfer, and ground deformation. From the numerical results, it has been found that ground deformation is induced by generation and dissipation of water and gas, and by reduction of soil strength due to the loss of hydrates.

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