ABSTRACT
The aim of this study was to refold the OvisAries leukocyte antigen (OLA) class Ⅰ protein with peptides derived from sheeppox virus (SPPV) to identify SPPV T cell epitopes. Two pairs of primers were designed based on the published sequence of a sheep major histocompatibility complex Ⅰ to amplify the heavy chain gene of OLA Ⅰ α-BSP and the light chain gene of OLA Ⅰ-β2m. Both genes were cloned into a pET-28a(+) expression vector, respectively, and induced with ITPG for protein expression. After purification, the heavy chain and light chain proteins as well as peptides derived from SPPV were refolded at a ratio of 1:1:1 using a gradual dilution method. Molecular exclusion chromatography was used to test whether these peptides bind to the OLA Ⅰ complex. T-cell responses were assessed using freshly isolated PBMCs from immunized sheep through IFN-γ ELISPOT with peptides derived from SPPV protein. The results showed that the cloned heavy chain and light chain expressed sufficiently, with a molecular weight of 36.3 kDa and 16.7 kDa, respectively. The protein separated via a SuperdexTM 200 increase 10/300 GL column was collected and verified by SDS-PAGE after refolding. One SPPV CTL epitope was identified after combined refolding and functional studies based on T-cell epitopes derived from SPPV. An OLA Ⅰ/peptide complex was refolded correctly, which is necessary for the structural characterization. This study may contribute to the development of sheep vaccine based on peptides.
Subject(s)
Animals , Capripoxvirus , Epitopes, T-Lymphocyte/genetics , Peptides/genetics , Poxviridae Infections , Sheep , Sheep DiseasesABSTRACT
Objective To observe the value of optimized temporal parallel acquisition technique (TPAT) sequence in evaluating cardiac structure and function in arrhythmia patients.Methods Totally 33 arrhythmia patients (arrhythmia group) and 48 normal rhythm subjects (normal group) underwent cardiac MRI with conventional cine (balanced steadystate free-precession [bSSFP]) sequence and optimized TPAT sequence.Myocardial thickness,cardiac function,myocardial strain parameters of left ventricle and image quality of 2 sequences were compared in the two groups,respectively.Results In arrhythmia group,there was statistical difference of myocardial thickness in 12 myocardial segments between the 2 sequences (all P ＜ 0.05),as well as peak and average values of myocardial radial and circumferential strain (all P＜0.05).In normal group,there was no statistical difference of myocardial thickness and stain parameters between the 2 sequences (all P＞0.05).Additionally,no statistical difference of cardiac function was found between the 2 sequences in two groups (all P＞0.05).In arrhythmia group,the image quality of optimized TPAT sequence was better than that of bSSFP sequence (P＜0.05).Conclusion For arrhythmia patients,optimized TPAT cine sequence could improve image quality of cardiac MRI.
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Objective To explore the feasibility of delineation of the atherosclerotic plaque in carotid artery using compressed sensing three dimensional motion-sensitized driven equilibrium prepared rapid gradient echo (CS-3D MERGE) technique. Methods Twenty-three patients who underwent carotid endarterectomy (CEA) were enrolled prospectively. In all patients, bilateral carotid arteries were scanned by CS-3D MERGE and contrast-enhanced MR angiography (MRA) simultaneously. Image quality of CS-3D MERGE images was scored. Images from the CS-3D MERGE sequence and contrast-enhanced MRA were used to measure the carotid stenosis, which were divided into four groups:normal group, mild stenosis group, moderate stenosis group, and severe stenosis group. The results were compared between the two methods. And images from the CS-3D MERGE sequence were compared with corresponding histology in identifying major plaque components including lipid rich necrotic core (LRNC), intraplaque hemorrhage (IPH), and calcification (CA). Spearman rank correlation coefficient was used to compare the correlation between the CS-3D MERGE sequence and contrast-enhanced MRA in measuring the carotid stenosis. Agreement was tested comparing images from the CS-3D MERGE sequence with corresponding histology in identifying major plaque components including lipid-rich necrotic core, intraplaque hemorrhage, and calcification. Results Twenty-three CEA patients finished bilateral CS-3D MERGE scanning successfully. Image quality was 3.16±0.25. There was an excellent correlation between CS-3D MERGE and MRA in measuring stenosis (r=0.95, P<0.01). The agreement between CS-3D MERGE and histological results for LRNC detection was 76.2% (16/21). It was less sensitive for IPH detection (71.4%, 15/21). CS-3D MERGE identified all CA accurately (100.0%, 21/21). Sensitivity and specificity were 86.6% (13/15) and 50.0% (3/6) for LRNC, 73.3% (11/15) and 66.6% (4/6) for IPH, 100.0% for CA respectively(16/16, 5/5). Conclusion CS-3D MERGE, a single sequence, can be used to quantify carotid stenosis and plaque components conveniently.
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Objective To explore the clinical application value of left atrial function with feature tracking cardiac magnetic resonance imaging (FT-CMR) by evaluating preliminarily left atrial strain and strain rate in patients with atrial fibrillation. Methods Thirty patients with paroxysmal atrial fibrillation, thirty patients with persistent atrial fibrillation and twenty-two healthy subjects were enrolled. All the subjects underwent cardiac magnetic resonance imaging with the real steady-state free precession(SSFP) sequence. FT-CMR parameters included left atrial strain and strain rate parameters, left atrial volume and function parameters were detected by using offline cardiovascular analysis software, respectively. Left atrial strain and strain rate parameters included left atrial total strain(Εs), passive strain(Εe), active strain(Εa), peak positive strain rate(SRs), peak early negative strain rate(SRe)and peak late negative strain rate(SRa). Volume and function parameters included maximum of left atrial volume(LAVmax), minimum of left atrial volume(LAVmin), total left atrial emptying fraction(LATEF), passive left atrial emptying fraction(LAPEF)and active left atrial emptying fraction(LAAEF). The differences in the general data among the paroxysmal atrial fibrillation group, the persistent atrial fibrillation group and the control group were compared by usingχ2 test or ANOVA analysis. The differences in all parameters between the atrial fibrillation group and the control group, the paroxysmal atrial fibrillation group and the persistent atrial fibrillation group were compared by using independent t test. Left atrial strain and strain rate parameters on an intra-observer and inter-observer were determined by intraclass correlation coefficient(ICC)analyses. Results Compared to control group, LAVmax and LAVmin in atrial fibrillation group were significantly increased(t=9.737,7.889,P<0.001);The LATEF and LAPEF had no significant difference, the LAAEF in two groups had statistically significant difference(t=-4.762,P<0.001).The absolute value of Es, Ee, Ea, SRs, SRe, SRa in atrial fibrillation group were significantly reduced than in control group(t=-7.732,-6.610,-6.493,-7.546, 6.864, 5.917,P<0.001). Compared with paroxysmal atrial fibrillation group, LAVmax and LAVmin in persistent atrial fibrillation group were increased obviously, LATEF and LAPEF were significantly decreased, and the differences were statistically significant(t=-4.575,-5.524, 4.002, 4.028,P<0.001).The LAAEF in two groups had no statistically significant difference. Compared with strain and strain rate in two groups, absolute value of Es, Ee, Ea, SRs, SRe, SRa in persistent atrial fibrillation group significantly decreased than in paroxysmal atrial fibrillation(t=4.310, 3.128, 4.465, 5.496,-3.290,-3.863,P<0.001). The intra-group and inter-group had well correlation coefficients between the observers in the left atrial strain and strain rate parameters of the subjects(ICC=0.85—0.94,0.81—0.90). Conclusions FT-CMR technique can be used to assess the left atrial strain and strain rate in patients with atrial fibrillation;Left atrial reservoir, conduit and booster-pump functions in patients with atrial fibrillation were impaired. Patients with persistent atrial fibrillation had worse left atrial function throughout the entire cardiac cycle compared with those with paroxysmal atrial fibrillation.
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Objective To investigate the diagnostic performance of stress cardiac magnetic resonance(CMR) for evaluating low-risk patients with suspected acute coronary syndrome(ACS).Methods Twenty-two patients with low risk of suspected ACS were prospectively and consecutively enrolled in this study.Diagnostic performance of stress CMR was compared with single-photon emission computed tomography(SPECT) for diagnosis of myocardial ischemia with coronary angiography (CAG) as the reference method.Results On the patient-based level analysis,the diagnostic performance of CMR for detection of ACS was sensitivity 93% and specificity 75%.The corresponding value of SPECT was 79%,63%.The area under the ROC (AUC) of CMR was 0.897, which was slightly superior to that of SPECT at 0.723 (P=0.19).On the per-vessel assessment, the diagnostic value of CMR was sensitivity 89%,specificity 87%, while the corresponding value of SPECT was 68%,83%.The AUC of CMR was 0.923,which was significantly higher than that of SPECT at 0.774 (P<0.05).Furthermore, the AUC of CMR was significantly superior to that of SPECT with AUC being 0.900 and 0.553 in the left anterior descending (LAD) vessels (P=0.009 6).Conclusion Stress perfusion CMR has excellent diagnostic performance in low risk ACS patients.Compared with SPECT,stress perfusion CMR performed better in the low-risk ACS populations.
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Objective To investigate the value of contrast enhancement T1 mapping in detection of diffuse myocardial fibrosis in cardiomyopathy, and the relationship between myocardial fibrosis and cardiac function. Methods From September 2013 to September 2014, 76 cases of cardiomyopathy patients (including myocarditis) and 33 cases of healthy controls were enrolled in our study. All the subjects underwent cardiac MR (CMR) examination. Scan sequences included cine MR, pre-contrast and post-contrast T1 mapping and late gadolinium enhancement (LGE) imaging. The pre-/post-contrast left ventricle average T1 value and cardiac function of patients and controls were measured and compared by using independent-samples t test. According to the LGE imaging, all the subjects were subsequently divided into LGE positive group, LGE negative group and control group. The myocardial average T1 value and cardiac function among the three sub-groups were compared by using one-way ANOVA, and the relationship among them were analyzed by using Pearson correlation. Results Among the 76 cases of non-ischemia cardiomyopathy patients, 51 cases (67.1%) had LGE. Compared with controls, cardiomyopathy patients presented with higher pre-contrast T1 value [(1 306.4 ± 84.6)ms vs. (1 266.6 ± 57.3)ms, t=2.10, P0.05). There were correlation between pre-/post-contrast left ventricle T1 value and ejection fraction (EF) in cardiomyopathy patients (r=-0.252,-0.217, P0.05). Conclusions The average pre-/post-contrast T1 value in left ventricle myocardium are helpful for detection of diffuse fibrosis in cardiomyopathy patients. The LGE positive is a sign that can greatly change the T1 value of the myocardial tissue, meanwhile, myocardial fibrosis is negative correlated with ejection fraction in cardiomyopathy patients.