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Objective:To investigate the protective mechanism of remote ischemic preconditioning (RIPC) on cerebral ischemia-reperfusion (I/R) injury in rats.Methods:Forty-eight SD rats were randomly divided into sham operation group, RIPC group, I/R group, RIPC+I/R group, and compound C group ( n=9 in each group). The neurological function score, cerebral infarction volume (TCC staining) and neuronal apoptosis rate (TUNEL staining) were measured. The activity of superoxide dismutase (SOD) 2 and malondialdehyde level in homogenate of brain tissue were detected. Expression levels of AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α signaling pathway-related proteins in brain tissue were detected by Western blot. Results:The neurological deficit score, cerebral infarction volume and neuron apoptosis rate in the I/R group were significantly higher than those in the sham operation group (all P<0.05). Compared with the I/R group, the neurological deficit score, cerebral infarction volume and neuron apoptosis rate in the RIPC+I/R group were significantly decreased (all P<0.05). Compared with the RIPC+I/R group, the neurological deficit score, cerebral infarction volume and neuron apoptosis rate in the compound C group were significantly increased (all P<0.05). Compared with the sham operation group, the SOD activity in the I/R group was significantly decreased, and the malondialdehyde content was significantly increased (all P<0.05). Compared with the I/R group, the SOD activity in the RIPC+I/R group was significantly increased, and the malondialdehyde content was significantly decreased (all P<0.05). Compared with the RIPC+I/R group, the SOD activity in the compound C group was significantly decreased, and the malondialdehyde content was significantly increased (all P<0.05). Compared with the sham operation group, the expressions of AMPK, p-AMPK, PGC-1α, nuclear respiratory factor (NRF)-1, mitochondrial transcription factor A (TFAM), SOD2, uncoupling protein 2 (UCP2), cytochrome C (CytC), and apoptosis-inducing factor (AIF) in the brain tissue of the I/R group were significantly increased (all P<0.05). Compared with the I/R group, the expressions of AMPK, p-AMPK, PGC-1α, NRF-1, TFAM, SOD2 and UCP2 in the ischemic brain tissue of the RIPC+I/R group were significantly increased, while the expressions of CytC and AIF were significantly decreased (all P<0.05). Compared with the RIPC+I/R group, the expressions of AMPK, p-AMPK, PGC-1α, NRF-1, TFAM, SOD2 and UCP2 in the brain tissue of the compound C group were significantly decreased, while the expressions of CytC and AIF were significantly increased (all P<0.05). Conclusions:RIPC has a protective effect on I/R injury. Its mechanism may be associated with the activation of AMPK/PGC-1α signaling pathway and maintaining mitochondrial biogenesis.
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Purpose To measure the longitudinal and transverse strain and displacement parameters of each segment of long axis myocardium on cardiac MRI film images of normal young volunteers using feature tracking technique (FT), and to analyze the regularity of left ventricular long axis strain and establish peak and time to peak (TTP) reference range concerning the longitudinal and transverse strain and displacement. Materials and Methods Cardiac film images of 29 healthy volunteers aged 24 to 34 were collected using Philips Multiva 1.5T MRI scanner, including three typical long axis planes of the left ventricular long axis, left ventricular outflow tract, and four-chamber view. The MRI film images were analyzed drawing on myocardial feature tracking software TOMTEC, and the peak value and TTP of longitudinal and transverse strain and displacement of the 16 AHA segments excluding apex cordis were obtained thereby. The regularity of each parameter concerning the plane, layer, and segment was summarized and analyzed. Results The TTP of longitudinal strain, longitudinal displacement and transverse strain were consistent among each myocardial segment, which was a constant indicator in (41.24±12.51) ％ RR interphase. The peak value of longitudinal displacement was represented by apex cordis (2.56±0.89) mm < middle (6.09±2.03) mm < cardiac base (8.07±2.05) mm, and the peak value of transverse displacement was manifested as apex cordis (4.57±1.18) mm < middle (5.65±0.84) mm < cardiac base (8.48 ±1.18) mm, which was consistent with cardiac geometric deformation visually observed. The longitudinal strain showed consistency on 2CH-3CH-4CH plane, whose peak reference value was (-22.46±13.19)％; while the peak value of transverse strain displayed no consistency on different planes. Conclusion The longitudinal strain of the left ventricular on different planes has consistent peak value and TTP, suggesting good reference value.
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Objective To investigate the differences in the survival time and the occurrence of complications between esophageal cancer patients treated with fully-covered segmented esophageal internal irradiation stent and esophageal cancer patients treated with conventional esophageal internal irradiation stent.Methods The clinical data of 66 esophageal cancer patients,who had received esophageal internal irradiation stents placement,were retrospectively analyzed.The patients were divided into the study group (using fullycovered segmented esophageal internal irradiation stent,n=30) and the control group (using conventional esophageal internal irradiation stent,n=36).The postoperative complications,including restenosis,stent migration,chest pain,etc.,and the survival time of the two groups were recorded.The results were analyzed,and P＜0.05 was considered to be statistically significant.Results No statistically significant difference in the restenosis rate existed between the study group and the control group (20.0％ vs.30.6％,P=0.403);although the median time of restenosis in the study group was longer than that in the control group (161.5 d vs.138 d,P=0.025).The stent migration rate in the study group was higher than that in the control group (33.3％ vs.8.3％,P=0.014).The difference in the median time of stent migration between the two groups was not statistically significant (91.5 d vs.166 d,P=0.236).No statistically significant difference in the median survival time existed between the two groups (186 d vs.178 d,P=0.486).No statistically significantly differences in the incidence of other stent-related complications existed between the two groups.Conclusion Fully-covered segmented esophageal internal irradiation stent can delay the occurrence of restenosis,although it can increase the stent migration rate to a certain degree.
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Objective To learn the endocardial strain patterns of the left ventricles on the short-axis views in normal youth volunteers using feature tracking techniques on cine cardiac MR imaging,and to build up the reference ranges of strain peak and time to peak (TTP) for endocardial strain analysis.Methods Twenty-nine normal youth volunteers aged from 24-34 years old were enrolled in the study in march 2015.The Cine MR imaging were acquired using balance FFE sequence with 24 phases for each cardiac cycle.The standard short-axis imaging planes were basal,mid-cavity and apical levels and divided into 16 segments.The peaks and TTPs of myocardial displacement and its velocity,radial and circumferential strain and strain rate and its velocity in each segment were calculated using feature tracking techniques.The data with normal distribution were analyzed by ANOVA and Student-Newman-Keuls (SNK) method,and Kruskal-Wallis and Wilcoxon rank sum test were used for the data without normal distribution.Results The peaks and TTPs of radial strain and strain rate differed in 16-segmental levels and basal,middle and apical plane levels and had no concordant reference ranges.The circumferential strain and strain rate were homogeneous at basal and middle plane levels [(-27.09 ±9.51)％,(1.94 ±0.98)/s,respectively].Their TTPs were homogenous [0.38 (0.08)RR,0.54 (0.08)RR,respectively],and there were no significant differences in planar-segments or inter-segment level.Except for middle level,the peaks of radial displacement and velocity differed in basal and apical levels and had no concordant reference ranges.But radial velocity TTPs were homogeneous in all 16 segments [0.21 (0.04)RR].Except for the radial strain rate,TTPs showed no significant difference between basal level and middle level.The measurements at apical level revealed high variance.No regular pattern could be found on individual peak and TTP curves of velocity and strain rate.Conclusion The peaks and TTPs of radial strain are different in segmental and planar levels without a concordant reference range.The peaks and TFPs of circumferential strain and the radial velocity rTTPs are homogeneous in middle and apical plane level and have homogeneous reference range.