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Yang Y.,PLA Fourth Military Medical University | Yang Y.,Aviation and Diving Medical Center | Sun Y.,PLA Fourth Military Medical University | Sun Y.,Beijing City University | And 5 more authors.

Background:Better understanding of acute stress responses is important for revision of DSM-5. However, the latent structure and relationship between different aspects of acute stress responses haven't been clarified comprehensively. Bifactor item response model may help resolve this problem.Objective:The purpose of this study is to develop a statistical model of acute stress responses, based on data from earthquake rescuers using Acute Stress Response Scale (ASRS). Through this model, we could better understand acute stress responses comprehensively, and provide preliminary information for computerized adaptive testing of stress responses.Methods:Acute stress responses of earthquake rescuers were evaluated using ASRS, and state/trait anxiety were assessed using State-trait Anxiety Inventory (STAI). A hierarchical item response model (bifactor model) was used to analyze the data. Additionally, we tested this hierarchical model with model fit comparisons with one-dimensional and five-dimensional models. The correlations among acute stress responses and state/trait anxiety were compared, based on both the five-dimensional and bifactor models.Results:Model fit comparisons showed bifactor model fit the data best. Item loadings on general and specific factors varied greatly between different aspects of stress responses. Many symptoms (40%) of physiological responses had positive loadings on general factor, and negative loadings on specific factor of physiological responses, while other stress responses had positive loadings on both general and specific factors. After extracting general factor of stress responses using bifactor analysis, significant positive correlations between physiological responses and state/trait anxiety (r = 0.185/0.112, p<0.01) changed into negative ones (r = -0.177/-0.38, p<0.01).Conclusion:Our results demonstrated bifactor structure of acute stress responses, and positive and negative correlations between physiological responses and stress responses suggested physiological responses could have negative feedback on severity of stress responses. This finding has not been convincingly demonstrated in previous research. © 2013 Yang et al. Source

Li M.,Aviation and Diving Medical Center | Li J.,Aviation and Diving Medical Center | Meng G.,Aviation and Diving Medical Center | Liu X.,Aviation and Diving Medical Center
Clinical and Experimental Pharmacology and Physiology

To provide pharmacological data for future clinical studies, this study investigated the protective effects of diltiazem on vascular endothelial cell (VEC) injury induced by angiotensin-II (AngII), hypoxia, and a combination of both treatments. The concentration of intracellular free calcium and the mitochondrial membrane potential in VEC were assessed as indicators of cell injury. An in vivo hypoxic animal model was used to test the protective effect of diltiazem on vascular endothelial tissues. Our study showed that AngII and hypoxia decreased the mitochondrial membrane potential in VEC, which was significantly inhibited by diltiazem. Diltiazem protected against VEC injury induced by the increased concentration of intracellular free calcium, which was associated with AngII and hypoxia. Diltiazem reduced the apoptosis of rat VEC under a sustained hypoxic condition. In addition, it reduced AngII and endothelin I levels in rat vascular endothelial tissues. Our study confirmed that AngII and hypoxia induced VEC injury by regulating the levels of mitochondrial membrane potential and intracellular free calcium. Diltiazem, a calcium channel blocker, protected VEC from AngII- and hypoxia-induced injury. © 2015 Wiley Publishing Asia Pty Ltd. Source

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