Resveratrol (RV), a naturally occurring phytoalexin, is known to possess a wide spectrum of chemopreventive and
chemotherapeutic effects in various stages of human tumors. p38, a member of the mitogen-activated protein kinase
(MAPK) superfamily, is always activated by some extracellular stimulus to regulate many cellular signal transduction
pathways, such as apoptosis, proliferation, and inflammation and so on. In this report, we assessed the effect of
SB203580, a specific inhibitor of p38 MAPK signaling pathway, on the RV-induced apoptosis in human lung
adenocarcinoma (A549) cells. CCK-8 assay showed that pretreatment with SB203580 significantly enhanced the
cytotoxicity of RV, which was further verified by analyzing the phosphatidylserine externalization using flow cytometry.
In order to further confirm whether SB203580 accelerated apoptosis via the intrinsic apoptosis pathway, we analyzed the
dysfunction of mitochondrial membrane potential (Δψm) of cells stained with rhodamine 123 by using flow cytometry
after treatment with RV in the absence and presence of SB203580. Our data for the first time reported that p38 inhibitor
SB203580 enhanced the RV-induced apoptosis via a mitochondrial pathway.
In this paper the results of study on the nonlinear and lasing output characteristics of an organic polymer system, are presented. To describe the dynamics of light field in the medium, the forced oscillation model of optical multi-stable and lasing system are used. For the matter model, the material with the conjugate structure, such as polydiacetylenes which energy structure can be reduced to a three-level system considered; meanwhile the approach of efficient susceptibility is used to deduce the nonlinear susceptibility. Under these conditions, theoretical analyzing and numerical simulation shows that the system appears special output characteristics and dynamic behaviors, also instability, responding to the incident signal, especially when it satisfies both the gain condition of amplifying and that of multi-stable states. Further, the relationship between the detuning and the conditions of light amplification in this system are given out. Moreover, we find the detuning condition can describe and generalize the "frequency pulling effect", in proper situation.