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Purpose Heat stress stimulation can cause various injuries in human umbilical vein endothelial cells (HUVEC), including apoptotic cell death and an increase in cell permeability. Propofol (PPF), a commonly used anesthetic, is known to have an important role in antioxidation as well as organ protection. Therefore, our aim is to evaluate the protective effects of PPF on heat stress (HS)-induced oxidative stress injury and its possible mechanism of action. Methods For HS + PPF, cells were treated with propofol followed by 2 h heat stress at 43 °C and then 4 h incubation under normal conditions. For propofol treatment, HUVEC were cultured in serum-free Dulbecco's modified Eagle medium supplemented with 0, 10, 25, or 50 [mu]M propofol for 6 h under normal conditions. Results During the study, we found that, in HS-induced cellular damage, the protective effect of propofol was related closely with its antioxidation properties. We further revealed that heat stress significantly reduced the level of manganese superoxide demutase (MnSOD) and Cu/Zn SOD, but that propofol could inhibit the reduction of MnSOD only. Transfection of HUVEC with MnSOD small interfering RNA (siRNA) markedly decreased the expression of MnSOD, and the protective effect of propofol in the MnSOD siRNA clones was significantly reduced. Conclusion Propofol protected the heat stress-injured cells, at least partly, through upregulating MnSOD expression, effectively reducing the direct or indirect cell damage caused by oxidative stress., Author(s): F. Wu[sup.1] , X. J. Dong[sup.2] , H. Q. Zhang[sup.3] , L. Li[sup.4] [sup.5] , Q. L. Xu[sup.6] , Z. F. Liu[sup.6] , Z. T. Gu[sup.4] [sup.5] , L. [...]

In this study, We demonstrated that Bax mitochondrial translocation plays a vital role in the initiation of the mitochondrial signaling pathway upon activation by heat stress. In addition, both p53 mitochondrial translocation and Ca2+ signal mediated MPTP opening activate Bax mitochondrial translocation. Employing pifithrin-α (a p53 mitochondrial translocation inhibitor) and CsA (a permeability transition pore (MPTP) inhibitor), we found that heat stress induced Bax mitochondrial translocation was significantly inhibited in cells pretreated with both PFT and CsA. Furthermore, we demonstrated that generation of reactive oxygen species (ROS) is a critical mediator in heat stress induced apoptosis and that the antioxidant MnTBAP significantly decreased heat stress induced p53 mitochondrial translocation and Ca2+ signal mediated MPTP opening, as well as the subsequent Bax mitochondrial translocation and activation of the caspase cascade. Taken together, our results indicate that heat stress induces apoptosis through the mitochondrial pathway with ROS dependent mitochondrial p53 translocation and Ca2+ dyshomeostasis, and the ensuing intro Bax mitochondrial translocation as the upstream events involved in triggering the apoptotic process observed upon cellular exposure to heat stress. [ABSTRACT FROM AUTHOR]

Two-dimensional 1H/13C polarization inversion spin exchange at the magic angle experiments were applied to single crystal samples of amino acids to demonstrate their potential utility on oriented samples of peptides and proteins. High resolution is achieved and structural information obtained on backbone and side chain sites from these spectra. A triple-resonance experiment that correlates the 1H-13Calpha dipolar coupling frequency with the chemical shift frequencies of the alpha-carbon, as well as the directly bonded amide 15N site, is also demonstrated. In this experiment the large 1H-13Calpha heteronuclear dipolar interaction provides an independent frequency dimension that significantly improves the resolution among overlapping 13C resonances of oriented polypeptides, while simultaneously providing measurements of the 13Calpha chemical shift, 1H-13C dipolar coupling, and 15N chemical shift frequencies and angular restraints for backbone structure determination., (Copyright 1999 Academic Press.)