Effect of sequential mechanical ventilation on cardiac function, endothelial injury and oxidative stress response in patients with cor pulmonale

Objective: To study the effect of sequential mechanical ventilation on cardiac function, endothelial injury and oxidative stress response in patients with cor pulmonale (CCP). Methods: Patients with cor pulmonale complicated by respiratory failure who were treated in Dongfeng People's Hospital between May 2014 and February 2017 were selected and randomly divided into the sequential group who received sequential mechanical ventilation combined with conventional therapy and the control group who received invasive positive pressure ventilation combined with conventional therapy. The serum levels of cardiac function-related neurohumoral indicators, endothelial injury indicators and oxidative stress response indicators were detected before treatment as well as 3 d and 7 d after treatment. Results: 3 d and 7 d after treatment, serum NT-proBNP, Copeptin, Ang-II, ALD, ET-1, vWF, sST2 levels of both groups of patients were significantly lower than those before treatment while NO, SOD, GSH-Px and T-AOC levels were significantly higher than those before treatment;serum NT-proBNP, Copeptin, Ang-II, ALD, ET-1, vWF, sST2, NO, 8-iso-PGF2a, MDA, SOD, GSH-Px and T-AOC levels of sequential group 3 d after treatment were not significantly different from those of control group;serum NT-proBNP, Copeptin, Ang-II, ALDET-1, vWF, sST2, 8-iso-PGF2a and MDA levels of sequential group 7 d after treatment were significantly lower than those of control group while NO, SOD, GSH-Px and T-AOC levels were significantly higher than those of control group. Conclusion: Sequential mechanical ventilation for cor pulmonale can improve the cardiac function and reduce the degree of endothelial injury and oxidative stress response.

SOLUTION CRYSTALLIZATION BEHAVIOR OF LINEAR AND STAR-SHAPED POLY(ETHYLENE GLYCOL)-b-POLY(ε-CAPROLACTONE) BLOCK COPOLYMERS

Lamellar crystals of diblock, triblock and four-arm poly（ethylene glycol）-b-poly（ε-caprolactone） （PEG-b-PCL） crystalline-crystalline copolymers were successfully obtained from their solution. Morphology and structure of lamellar crystals of crystalline-crystalline copotymers were investigated using tapping-mode atomic force microscopy （AFM） and selected area electron diffraction （SAED）. All of these samples showed the truncated-lozenge multilayer basal shapes with central screw dislocation or central stack, which were all obtained simultaneously from the oil bath. The diffraction pattern of PEG block lamellar crystal is attributed to the （120） diffracting planes and the pattern of PCL block lamellar crystal is attributed to the （1 I0） diffracting planes and （200） diffracting planes according to the SAED results. Four （110） crystal growth planes and two （200） crystal growth planes are discovered for the PCL blocks, but the （120） crystal growth planes of PEG blocks are hided in the figure of AFM. The crystalline structure of the four-arm copolymers （FA） is more disorder and confused than that of the diblock （DI） copolymer and the striated fold surface structures of lamellar crystals of four-arm copolymers （FA） are smoother than these of linear analogues, owing to the confused crystallization of blocks caused by the mutual restriction of blocks and the hindrance of the dendritic cores. In addition, the aspect ratio of FA is greater than that of the others. It is hypothesized that there are two reasons for the change of aspect ratios. First, the （200） diffracting planes of PCL crystals grew slowly compared to their （110） diffracting planes because of difference in the energy barrier. Secondly, edge dislocations on the （200） diffracting planes are also responsible for the variation of the aspect ratio. Consequently, the crystalline defects are augmented by the competing blocks crystallized simultaneously and the hindrance of the dendritic cores.