高场强MRI对臂丛神经损伤的诊断及其应用价值

目的探讨高场强MRI对臂丛神经损伤的诊断及其应用价值。方法回顾性分析我院2010年8月至2013年3月利用1.5T或3.0T MRI检查的20例臂丛神经损伤患者,将患者图像进行后处理,分析臂丛神经损伤的MRI影像学特点。结果臂丛神经损伤的类型按部位可分为节前损伤、节后损伤及混合型损伤(节前、节后均损伤)。MRI征象包括:(1)直接征象:1神经增粗,局部神经连续性中断,信号异常10例;2神经走行僵直、结构紊乱19例。(2)间接征象:1创伤性脊膜囊肿10例;2黑线征5例;3神经根袖形态变钝1例;4脊髓挫伤、肿胀及移位5例;5损伤的神经邻近软组织结构紊乱,水肿,肌肉萎缩,脂肪浸润18例。结论高场强MRI具有更高的软组织分辨率,能完整的显示臂丛神经的解剖及走行,能准确、直观的显示臂丛神经损伤的位置及范围。     

Pancreatic perfusion imaging method that reduces radiation dose and maintains image quality by combining volumetric perfusion CT with multiphasic contrast enhanced-CT

ObjectivesThe aim of this study is to propose and evaluate a new method of volumetric perfusion computed tomography (PCT) incorporated into pancreatic multiphasic contrast enhanced (CE)-CT in the clinical setting.MethodsIn this ethically approved study, PCT was incorporated into our existing scanning protocol in 17 patients and effective doses related to PCT were evaluated. CT values and signal-to-noise ratio (SNR) of anatomical structure were compared in diagnostic images that were acquired using 320-detector volumetric scan mode and 64-detector helical scan mode. In addition, focal lesion depiction was qualitatively assessed in the two groups. Perfusion parameters in normal pancreas were measured by two radiologists and the interobserver-reliability was assessed.ResultsThe effective dose of PCT was 5.1 ± 0.3 mSv. The actual effective dose (AED) including the dose used in volumetric scans for diagnostic imaging was 22.8 ± 5.3 mSv and the putative effective dose (PED) was 21.9 ± 9.1 mSv on average. There was no significant difference between AED and PED (p = 0.404). Compared with conventional helical scans, volumetric scans did not decrease CT values or SNR, but rather significantly increased those of the aorta in the arterial phase. Both groups had acceptable qualitatively assessed image quality with no significant difference in the depiction of each structure. There was almost perfect interobserver agreement in the measurement of perfusion parameters (mean ICCs > 0.9).ConclusionsOur scanning protocol for pancreatic perfusion CT provides high-quality images while requiring lower radiation doses than conventional methods.     

The roles and interaction of FXR and PPARs in the pathogenesis of nonalcoholic fatty liver disease

Background and study aimsTo identify the roles and interaction of farnesoid X receptor (FXR) and peroxisome proliferator activated receptors (PPARs) in Non-alcoholic fatty liver disease (NAFLD) pathogenesis.Material and Methods16 C57/BL male FXR knockout (KO) mice and sex- and age-matched C57/BL wild type mice were received either standard rodent chow or high-fat and sucrose diet (Blank control, NAFLD, FXR KO and FXR KO NAFLD) for 8 weeks. After that, all mice were sacrificed. Liver tissues and blood samples were collected for laboratory and RT-PCR examination.ResultsNAFLD, FXR KO and FXR KO NAFLD mouse models were successful established. Compared with blank control, FXR and PPAR-α mRNA expression decreased significantly (P < 0.05), PPAR-β expression increased slightly (P > 0.05), PPAR-γ expression increased significantly in NAFLD (P < 0.05). Slight increased PPAR-α mRNA expression (P > 0.05) and markedly decreased PPAR-β and PPAR-γ expression (P < 0.05) were found in FXR KO. Compared with FXR KO group, there was a slight increase in PPAR-αand PPAR-βmRNA expression (P > 0.05) and significant increase in PPAR-γ expression (P < 0.05) in FXR KO NAFLD group. Comparison with NAFLD, PPAR-α mRNA expression increased slightly (P > 0.05), PPAR-β and PPAR-γ expression decreased significantly (P < 0.05) in FXR KO NAFLD.ConclusionFXR and PPARs interaction may play important roles in NAFLD pathogenesis.     

Expression of chemokine receptor-4 in bone marrow mesenchymal stem cells on experimental rat abdominal aortic aneurysms and the migration of bone marrow mesenchymal stem cells with stromal-derived factor-1

This study investigated the expression and role of chemokine receptor-4 (CXCR4) in bone marrow mesenchymal stem cells (BMSCs) from experimental rats with abdominal aortic aneurysms (AAA) for migration of BMSCs. Sprague–Dawley rats were divided into an experimental group and control group (n = 18 each). AAA was induced with 0.75 M solution infiltrate for 30 minutes, after which the abdomen was rinsed and closed. Saline was used in place of CaCl₂ in the control group. CD34 and CD29 were detected by flow cytometry, the gene and protein expression of CXCR4 were detected by real-time polymerase chain reaction and western blot, respectively. The migration of BMSCs with stromal-derived factor-1 was detected by Transwell chamber. CD34 expression was negative and CD29 expression was positive. The gene and protein expression of CXCR4 were significantly higher in experimental group than them in control group (p < 0.05), the migration ability of BMSCs from the experimental group was significantly higher than that from the control group (p < 0.05). Stromal-derived factor -1/CXCR4 can enhance the migration of BMSCs in vitro in a rat AAA model.     

Liver fat accumulation measured by high-speed T2-corrected multi-echo magnetic resonance spectroscopy can predict risk of cholelithiasis

BACKGROUND Liver fat accumulation is associated with increased cholesterol synthesis and hypersecretion of biliary cholesterol, which may be related to the development of cholelithiasis.AIM To investigate whether liver fat accumulation measured by high-speed T2-corrected multi-echo magnetic resonance spectroscopy(MRS) is a risk factor for cholelithiasis.METHODS Forty patients with cholelithiasis and thirty-one healthy controls were retrospectively enrolled. The participants underwent high-speed T2-corrected multi-echo single-voxel MRS of the liver at a 3 T MR scanner. The proton density fat fraction(PDFF) and R~2 value were calculated. Serum parameters and waist circumference(WC) were recorded. Spearman's correlation analysis was used to analyze the relationship between PDFF, R~2, and WC values. Multivariate logistic regression analysis was carried out to determine the significant predictors of the risk of cholelithiasis. Receiver operating characteristic curve(ROC) analysis was used to evaluate the discriminative performance of significant predictors.RESULTS Patients with cholelithiasis had higher PDFF, R~2, and WC values compared with healthy controls(5.8% ± 4.2% vs 3.3% ± 2.4%, P = 0.001; 50.4 ± 24.8/s vs 38.3 ±8.8/s, P = 0.034; 85.3 ± 9.0 cm vs 81.0 ± 6.9 cm, P = 0.030; respectively). Liver iron concentration extrapolated from R~2 values was significantly higher in the cholelithiasis group(2.21 ± 2.17 mg/g dry tissue vs 1.22 ± 0.49 mg/g dry tissue, P = 0.034) than in the healthy group. PDFF was positively correlated with WC(r = 0.502, P 0.001) and R~2(r = 0.425, P 0.001). Multivariate logistic regression analysis showed that only PDFF was an independent risk factor for cholelithiasis(odds ratio = 1.79, 95%CI: 1.22-2.62, P = 0.003). ROC analysis showed that the area under the curve of PDFF was 0.723 for discriminating cholelithiasis from healthy controls, with a sensitivity of 55.0% and specificity of 83.9% when the cut-off value of PDFF was 4.4%.CONCLUSION PDFF derived from high speed T2-corrected multi-echo MRS can predict the risk of cholelithiasis.     

两种根管再治疗镍钛器械去除椭圆形弯曲根管内充填物的效果评价

目的:评价2种根管再治疗镍钛器械去除椭圆形弯曲根管内充填物的效果。方法:离体的80颗根管呈椭圆形且弯曲的下颌前磨牙经Hero642预备、热牙胶垂直加压充填后随机分为4组,分别用ProTaper Universal、R-Endo、Hero642和手用H锉去除根充物,测量各组根充物的残留量百分比和操作时间。结果:4组样本均有根充物残留,ProTaper Universal、R-Endo和Hero642组根充物残留量百分比、操作时间均少于手用H锉组(P<0.01),前3组间的差异无统计学意义(P>0.05)。结论:ProTaper Universal、R-Endo机动镍钛器械对椭圆形弯曲根管内充填物的清除效果优于手用器械,且可减少操作时间,但仍不能彻底清除根充物。     

Schick数字化成像系统的临床应用及图片效果分析

目的：探讨Schick数字化成像系统的临床应用,评价Schick数字化成像系统的成像质量。方法：随机选取Schick数字化成像系统所拍X线根尖片和Kodak根尖胶片各200张,比较其曝光时间和X线垂直角度,对其成像质量进行分级评价。结果：Schick数字化成像系统所拍根尖片成像质量I级者为90％,比Kodak根尖胶片高25％;Schick数字化成像系统所拍根尖片成像质量Ⅲ级和Ⅳ级所占比例为5％,与Kodak根尖胶片无明显差别。结论：采用Schi。k数字化成像系统拍摄根尖片成像质量优良,能较好地满足临床应用要求。     

镍铬合金、钴铬合金和纯钛金瓷结合强度的比较

目的比较镍铬合金、钴铬合金和纯钛的金瓷结合强度和金瓷界面特征。方法执行ISO9693[1]标准,采用三点弯曲试验分别测定在常规热处理条件下的镍铬合金、钴铬合金和纯钛的金瓷结合强度。运用扫描电镜和X射线衍射进行金瓷界面分析。结果金瓷结合强度分别为:镍铬合金:(37.56±2.92)Mpa,钴铬合金:(39.06±2.79)Mpa,纯钛:(32.61±5.62)Mpa,前两者组间差异无统计学意义(P>0.05),后者与前两者组间差异有统计学意义(P<0.05)。扫描电镜和X线衍射:镍铬合金和钴铬合金与瓷之间紧密接触,无裂纹,界面过渡层15～20μm。纯钛与瓷过渡层80μm,可见孔洞。纯钛基体表面可见约2μm黑色带。结论①钴铬合金与镍铬合金的金瓷结合强度接近,都大于纯钛的金瓷结合强度。②钴铬合金、镍铬合金、纯钛的金瓷结合强度都大于25Mpa,按ISO9693标准均可应用于临床。③金瓷之间存在结合介质,形成过渡层。     

TGF-β1对人唾液腺腺样囊性癌ACC-2细胞体外增殖、迁移和侵袭的影响

目的:探讨TGF-β1在腺样囊性癌的增殖、迁移和侵袭、浸润过程中的作用和相关机制。方法:以腺样囊性癌ACC-2细胞株为研究对象,采用TGF-β1刺激ACC-2细胞,MTT法检测ACC-2细胞的增殖能力,Transwell实验检测细胞迁移、侵袭能力,Western蛋白印迹检测ACC-2细胞MAPK(P38、JNK、ERK)的活化及MMP-2表达的变化,实时定量PCR检测ACC-2细胞中MMP-2的mRNA表达变化。采用SPSS17.0软件包对数据进行统计学分析。结果:TGF-β1刺激后,ACC-2细胞增殖能力无显著变化(P>0.05),但迁移、侵袭能力增强(均为P<0.01);同时,ACC-2细胞p-ERK1/2、p-P38和MMP-2蛋白表达升高(均为P<0.05),MMP-2 mRNA表达亦升高(P<0.01),但p-JNK1/2蛋白无显著变化(P>0.05)。结论:TGF-β1可增强人唾液腺腺样囊性癌ACC-2细胞的迁移和侵袭能力,活化p-ERK1/2和p-P38,上调MMP-2的表达。TGF-β1/MAPK/MMP-2通路可能参与人唾液腺腺样囊性癌ACC-2细胞侵袭能力的调节。