反义hTERT对胃癌细胞SGC7901 VEGF及其受体表达的影响

目的研究反义hTERT对胃癌细胞SGC7901 VEGF及其受体表达的影响,探讨其对肿瘤发展和转移的影响.方法以端粒酶逆转录酶组分hTERT cDNA为模板构建反义hTERT逆转录病毒表达载体,包装重组逆转录病毒后感染胃癌SGC7901细胞,用半定量RT-PCR检测基因转染前后VEGF-C及其受体Flt-4 mRNA表达水平的变化,免疫组化法检测VEGF-C、Flt-4蛋白表达.结果反义hTERT稳定转染后SGC7901细胞VEGF-C及其受体VEGFR-3（Flt-4） mRNA和蛋白表达均受到明显抑制.结论反义hTERT可有效抑制胃癌细胞VEGF-C及其受体Flt-4的表达,阻断肿瘤血管和淋巴途径转移.     

Ascl2表达抑制对结肠癌细胞上皮-间质转化的影响

目的 探讨肿瘤干性因子Ascl2对结肠癌细胞上皮-间质转化(EMT)的影响.方法 将Ascl2的shRNA干扰质粒转染至结肠癌HT-29和LS174T细胞,采用G418筛选建立稳定转染的细胞系,MTT及平板克隆形成实验观察Ascl2干扰对细胞增殖和克隆形成能力的影响,Real-time PCR和Western blotting检测Ascl2干扰对EMT相关蛋白E-钙黏蛋白和波形蛋白表达的影响.结果 MTT检测发现,转染Ascl2干扰质粒后72h和96h,HT-29和LS174T细胞的增殖速率明显降低(P＜0.05);平板克隆形成实验结果显示,干扰后的HT-29和LS174T细胞克隆形成数明显少于未转染及转染对照质粒的HT-29和LS174T细胞(P＜0.05).Real-time PCR和Western blotting检测发现,干扰后的HT-29和LS174T细胞E-钙黏蛋白mRNA和蛋白表达水平上调(P＜0.05),波形蛋白的mRNA和蛋白表达水平下调(p＜0.05).结论 Ascl2 RNA干扰可导致结肠癌HT-29和LS174T细胞增殖能力下降及EMT逆转.     

人端粒酶反转录酶基因转染对人胎儿表皮干细胞增殖的影响

目的 探讨外源性人端粒酶反转录酶(hTERT)基因转染对人胎儿表皮干细胞增殖的影响.方法 采用脂质体转染法,将含有hTERT基因的质粒pIRES2-EGFP-hTERT和卒载体质粒pIRES2-EGFP分别导人体外培养的人胎儿表皮干细胞,并用G418筛选法进行抗性克隆的筛选.用RT-PCR和Western blot检测表皮十细胞hTERT mRNA及其蛋白的表达,端粒重复序列扩增法(TRAP)-ELISA检测其端粒酶活性,流式细胞仪检测细胞周期.结果 非转染组和空载体质粒转染组表皮干细胞弱表达hTERT mRNA和蛋白,而质粒转染组表皮干细胞强表达hTERT mRNA和蛋白;与非转染组和窄载体质粒转染组比较,质粒转染组表皮干细胞端粒酶活性的表达量显著升高,G_0/G_1期细胞比例明显下降,而S、G_2/M期细胞比例升高,增殖指数增加.结论 外源性hTERT基因转染能有效增强体外培养的人表皮干细胞hTERT mRNA和蛋白的表达及端粒酶活性,细胞增殖能力明显增强.     

Syk表达对乳腺肿瘤细胞侵袭迁移作用的影响

目的:探讨脾源性酪氨酸激酶(spleen tyrosine kinase, Syk)在人乳腺癌细胞中的表达及其对肿瘤细胞侵袭迁移能力的影响.方法:RT-PCR法、免疫荧光法检测不同侵袭能力乳腺癌细胞株--MCF-7(低侵袭性)和MDA-MB-231(高侵袭性) Syk mRNA及蛋白的表达;采用脂质体介导的方法,将Syk基因导入Syk(-)乳腺癌细胞株,利用Transwell小室法检测Syk基因对肿瘤细胞侵袭迁移能力的影响.结果:Syk mRNA及蛋白在MCF-7细胞中呈中等程度表达,在MDA-MB-231中表达缺失;转染Syk基因的MDA-MB-231细胞与转染空载体及未转染MDA-MB-231细胞相比,侵袭及迁移实验中的穿膜细胞数(总迁移细胞数/5HPF)均明显减少(P＜0.05).结论:Syk表达可降低乳腺肿瘤细胞体外侵袭迁移能力.     

血管内皮生长因子C正、反义真核表达载体的构建及鉴定

目的克隆血管内皮生长因子C（VEGF-C）基因,构建VEGF-C正、反义真核表达载体,鉴定并分析其基因序列。方法从处于对数生长期的人SGC-7901细胞中提取组织总RNA,用RT-PCR方法扩增出VEGF-C基因的正、反义全长cDNA。利用大肠杆菌转化并制备质粒pCI-neo和pcDNA3。分别用XbaI＋EcoRⅠ及HindⅢ＋EcoRⅠ双酶切两组质粒和VEGF-C cDNA,并将正、反义VEGF-C cDNA克隆到真核表达载体pcDNA3和pCI-neo中。酶切鉴定、质粒双向测序鉴定重组基因。结果扩增出VEGF-C基因全长cDNA,大小约1.3kb。克隆出正、反义重组质粒为pcDNA3-sense VEGF-C,pCI-neo-antisense VEGF-C,电泳结果显示条带大小约6.8kb。碱基测序证实重组质粒中导入的DNA片段碱基序列与预期的设计路线相符且两片段互补、方向相反。结论正确克隆VEGF-C基因,成功构建了VEGF-C正、反义真核表达载体,为下一步研究反义VEGF-C转染VEGF-C基因高表达的肿瘤细胞后对其体外生长的影响创造了条件,也为进一步研究VEGF-C在胃癌新生淋巴管的形成和转移中的作用奠定了基础。     

长非编码RNA HOXD-As2通路抑制直肠癌细胞增殖、转移作用机制研究

目的 探讨长非编码RNA(LncRNA)HOXD-As2通路抑制直肠癌细胞增殖、转移的潜在机制。方法 在直肠癌HCT116与HT29细胞中,转染阴性设为对照组,转染LncRNA HOXD-As2过表达质粒设为HOXD-As2组;转染空载体Vector设为Vector组,转染HOXD8过表达质粒设为HOXD8组。采用荧光素酶报告实验检测LncRNA HOXD-As2与靶基因HOXD8的相互作用。检测并比较4组细胞活力、增殖、侵袭、细胞迁移水平、上皮-间质转化相关蛋白表达水平及磷酸化蛋白激酶B/蛋白激酶B(p-AKT/AKT)、磷酸化磷脂酰肌醇-3-激酶/磷脂酰肌醇-3-激酶(p-PI3K/PI3K)、磷酸化雷帕霉素机械靶蛋白/雷帕霉素机械靶蛋白(p-mTOR/mTOR)蛋白相对表达水平。结果 与对照组相比,HOXD-As2组荧光素酶活性下降,而mRNA、蛋白相对表达情况增加,差异均有统计学意义(P<0.05)。与对照组相比,HOXD-As2组直肠癌细胞HCT116、HT29中HOXD8的mRNA与蛋白表达水平均显著上升,差异均有统计学意义(P<0.05)。与Vector组相比...     

反义转化生长因子β1基因修饰对肌腱细胞生物学活性的影响

目的 观察腱鞘成纤维细胞经反义TGF-β1基因修饰后生物学活性的改变,为肌腱术后粘连防治提供新的思路.方法 取新西兰白兔6只,分离、培养腱鞘成纤维细胞,利用脂质体将反义TGF-β1表达载体pcDNA3-TGF-β(-)导入腱鞘成纤维细胞,RT-PCR检测肌腱细胞TGF-β1、Ⅰ、Ⅲ型胶原mRNA的表达,Western blot法检测Ⅰ型胶原蛋白的表达.结果 RT-PCR显示基因修饰后肌腱细胞TGF-β1、Ⅰ、Ⅲ型胶原的mRNA表达显著降低,与未传染组和空转染组比较,差异有统计学意义(P<0.01);Western blot结果 显示基因修饰后肌腱细胞Ⅰ型胶原蛋白表达降低,与未传染组和空转染组比较,差异有统计学意义(P<0.01). 结论 反义TGF-β1质粒能成功导入肌腱细胞中,并有效降低TGF-β1的表达和Ⅰ、Ⅲ型胶原的产生,减少肌腱的粘连成分,可能为防止肌腱损伤后的粘连起一定的作用.     

阻断血管内皮生长因子表达对食管癌细胞放射敏感性的影响

目的 观察转染反义VEGF cDNA质粒和反义寡核苷酸后,TE-1食管癌细胞在体外的生长状况、VEGF表达水平及其放射敏感性的变化。方法 分别用反义VEGF cDNA质粒及空载体质粒和反义VEGF寡核苷酸经Lipofectamine^TM2000介导转染TE-1细胞,然后经γ射线照射。采用RT-PCR、Western blotting、流式细胞术、MTT法和克隆形成实验分别检测4组细胞照射前后VEGF基因的表达、凋亡率和细胞周期变化、细胞增殖情况以及转染细胞放射敏感性的变化。结果 将反义VEGF cDNA和反义寡核苷酸成功转入食管癌TE-1细胞后,VEGF表达水平明显降低,细胞增殖反应、细胞周期无明显变化,亦未见明显凋亡发生。照射后4组细胞增殖情况未见明显差异;反义组细胞凋亡率略有上升, 放射敏感性增加。结论 转染反义VEGF cDNA质粒和反义寡核苷酸可抑制食管癌TE-1细胞VEGF表达,联合放射线作用,对TE-1细胞的增殖无明显影响,而对其放射敏感性有增强作用。     

实时定量PCR检测GDNF基因转染大鼠BMSCs后的转录水平

目的 了解外源性胶质细胞源性神经营养因子(GDNF)基因在大鼠骨髓间充质干细胞(BMSCs)中的转录水平.方法 体外分离培养大鼠BMSCs,将其随机分为GDNF基因转染组、空质粒转染组和未转染组3组;GDNF基因转染组和空质粒转染组分别用GDNF基因和空质粒重组腺病毒感染BMSCs,并按感染后培养时间的不同(3、6、9和12天)又分为4个亚组.采用实时定量PCR技术检测GDNF基因在BMSCs中的转录水平.结果 空质粒转染组和未转染组无GDNF mRNA的表达,GDNF基因转染组在转染后3～12天的GDNF mRNA相对表达量为0.007 51±0.000 67.结论 腺病毒介导的基因转染技术将GDNF基因转染至骨髓间充质干细胞中,有外源性基因GDNF mRNA的表达,这为进一步研究以GDNF基因转染的BMSCs治疗中枢神经系统疾病奠定了基础.     

IL-8基因真核表达载体的构建及其在OVCAR-3卵巢癌细胞中的表达

目的:构建白细胞介素8(interleukin 8,IL-8)基因真核表达载体,瞬时转染OVCAR-3卵巢癌细胞,为进一步探讨其与肿瘤发生发展关系奠定基础.方法:采用RT-PCR法自健康志愿者外周血单个核细胞扩增IL-8基因,构建pcDNA3.1( )/IL-8重组质粒;脂质体介导将外源基因转入OVCAR-3卵巢癌细胞,半定量RT-PCR、Western印迹及ELISA法鉴定其mRNA及蛋白瞬时表达后,MTT法检测细胞转染前后生长增殖特性的改变,FCM检测细胞周期的变化.结果:重组质粒双酶切电泳结果显示,相应位置(300 bp,5 400 bp)可见2条清晰特异的DNA条带;DNA测序结果进一步显示,重组质粒中插入的基因片段全长 300 bp,编码序列与GenBank报道的基因序列相符,阅读框保持不变;RT-PCR、Western 印迹检测及ELISA检测结果显示,转染后OVCAR-3细胞IL-8 mRNA及蛋白表达水平均明显升高(P<0.05);MTT检测结果显示,IL-8转染细胞组转染3 d后的光密度值(D值)显著高于未转染细胞组(P<0.05);FCM分析结果显示,OVCAR-3细胞转染IL-8基因后进入S期的细胞比例显著增高,增殖指数也相应上升,与未转染及空质粒转染组细胞相比,差异显著(P<0.05).结论:IL-8基因真核表达载体成功构建并瞬时转染OVCAR-3卵巢癌细胞;IL-8可以自分泌方式促进卵巢癌OVCAR-3细胞生长增殖.     

Stress MR imaging for evaluation of popliteal artery entrapment

The popliteal artery entrapment (PAE) syndrome has been recognized as a cause of arterial occlusion in young people. It is the result of an anomaly of the relationship between the popliteal artery and the gastrocnemius muscle. Eight young healthy volunteers (16 legs) and six patients (10 legs) with suspected PAE underwent magnetic resonance (MR) imaging. Gradient-echo images were obtained in axial planes with the leg at rest and during active plantar flexion against resistance. Imaging at rest allowed identification of PAE signs in only one leg, which had an anomalous medial course of the popliteal artery. In the other cases, only the stress technique was able to show signal loss in the popliteal artery due to muscular compression (two legs) or the presence of accessory muscle slip around the vessel (two legs), as confirmed at surgery. MR imaging is therefore a useful technique for the diagnosis of PAE because of its capability of combining information obtainable with other modalities.     

MR imaging of muscle and tender points in fibromyalgia

Fibromyalgia is a syndrome manifested by chronic, diffuse muscu-loskeletal aching and soreness, palpable muscle tender points, and other symptoms. Standardized clinical diagnostic criteria have recently been developed. Skeletal muscle has been postulated as the end organ in this disease. Biochemical, histologic, electromyographic, and conventional radiographic studies have demonstrated no definitive abnormality. This study sought to establish whether magnetic resonance (MR) imaging could demonstrate any abnormality in these patients. Eighteen patients were entered in the study, 14 of whom were able to complete their examinations. T1 -weighted, T2-weighted, gradient-echo, and STIR (short-tau inversion-recovery) sequences were performed in all patients, with selected patients examined with T1weighted, gadopentetate dimeglu-mine-enhanced sequences. The trapezius and suboccipital regions were imaged in patients who, clinically, had active fibro-myalgia. No abnormalities could be detected. The authors conclude that the conventional MR imaging used in this study was unable to depict any primary skeletal muscle abnormality in fibromyalgia.     

Uterine contractions: Possible diagnostic pitfall at MR imaging

A total of 206 nongravid patients with various gynecologic problems underwent pelvic magnetic resonance (MR) examinations that included both sagittal T2-weighted and contrast agent–enhanced T1-weighted images. MR images were retrospectively reviewed to identify changes in endometrial configuration on serial images obtained during the same MR examination. In 20 MR examinations (all in women of reproductive age), endometrial distortion due to myometrial bulging was noted on T2-weighted or contrast-enhanced T1-weighted images. It was absent on other MR images obtained at different times. Myometrial bulging exhibited low signal intensity in 18 examinations. The finding resembled adenomyosis or leiomyoma on T2-weighted or contrast-enhanced T1-weighted images. These results evidence the presence of transient myometrial bulging and transient low-intensity myometrium in the nongravid uterus. This phenomenon is thought to represent uterine contraction. Clinicians should be aware of the potential presence of transient low-signal-intensity myometrial bulging that could present diagnostic problems in the normal uterus.     

Controversies in cervical spine imaging in trauma patients

No area of emergency radiology has generated as much discussion in recent years as the subject of cervical spine imaging for trauma patients. This review will be in three parts. The first will examine the indications for cervical imaging and will focus on those factors that make patients at high risk or low risk for cervical injury. The second part will discuss the merits of radiography and computed tomography as the main screening diagnostic examination. In addition to the roles of each modality in the evaluation process, such factors as efficacy of diagnosis, time (duration) of study, and cost will be discussed. Finally, the third part will explore the methods currently employed to clear the cervical spine in comatose patients.Presented at the Annual Meeting of the American Society of Emergency Radiology, Las Vegas, Nevada, 22–25 October, 2003     

Brodie Abscess: MR imaging appearance in 10 patients

The magnetic resonance (MR) imaging features of Brodie abscess have not yet been fully evaluated. Ten patients with Brodie abscess, eight of long bone and two of vertebra, were studied with MR imaging. Long bone abscess had a characteristic “target” appearance with four layers: (a) a center with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR (short-inversion-time inversion recovery) images, (b) an inner ring isointense to muscle on T1-weighted images and with high signal intensity on T2-weighted and STIR images, (c) an outer ring hypoin-tense on all images, and (d) a peripheral halo hypointense on T1-weighted images. In six of eight cases, a soft-tissue mass was found. The two vertebral abscesses had a less specific appearance, with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR images. Only the peripheral halo was clearly identified in both cases.     

Dynamic contrast-enhanced MR imaging assessment of vascularized free fibular grafts

Magnetic resonance (MR) imaging may be a noninvasive method for assessing perfusion of vascularized bone grafts placed for treatment of avascular necrosis. One proximal femur of seven beagles was devascularized, with insertion of a vascularized fibular graft. MR imaging at 1 week (seven dogs) and 6 weeks (five dogs) after surgery included pre- and postcontrast spin-echo sequences, unenhanced twodimensional time-of-flight (TOF) vascular imaging, and dynamic gradient-echo imaging during infusion of gadolinium. Relative signal intensity values of selected regions obtained from the dynamic gradientecho images were plotted as percent enhancement versus time. In the operated hip, MR imaging did not show enhancement in six of seven femoral heads and greater trochanters at 1 week after surgery, with similar results after 6 weeks. MR imaging of fibular grafts 6 weeks after surgery showed an initial rapid increase in enhancement and a subsequent slower increase in five of five dogs, although no enhancement was seen in six of seven dogs at 1 week. These findings contrasted with a rapid initial increase in enhancement followed by slow decline in non-operated hips. Two-dimensional TOP imaging did not show the vascular pedicle of the graft in any dog. Findings of radionuclide bone scanning performed 1 week after surgery were consistent with devascularization of the operated femur and fibular graft. However, tetracycline distribution and histologic findings confirmed the viability of five of five grafts within the devascularized femurs 6 weeks after surgery. Thus, dynamic contrast-enhanced MR imaging at 6 weeks after surgery is valuable for assessing vascular bone graft perfusion, while similar imaging at 1 week may suggest otherwise.     

Right-side aortic arch with aneurysm of aberrant left subclavian artery: MR imaging appearance.

Reports of aneurysms of the subclavian artery in both normal and anomalous aortic arches have been rare. The authors describe a patient with a right-side aortic arch and an aneurysm of the aberrant left subclavian artery, which, to the authors' knowledge, is a previously unreported association. At presentation, the aneurysm appeared as a calcified left superior mediastinal mass. Magnetic resonance imaging enabled preoperative diagnosis and guided surgical planning.     

Adrenal tissue characterization with 0.5-T MR imaging: Value of T2*-weighted images

The authors investigated the value of magnetic resonance (MR) imaging at 0.5 T for distinguishing adrenal adenomas from adrenal metastases. The series included 23 adrenal adenomas (18 nonhyperfunctioning, five hyperfunctioning) and 23 adrenal metastases from various organs. Adrenal tumor–liver signal intensity ratios on T1-, T2-, and T2*-weighted images were calculated for adrenal tissue characterization. Adrenal adenomas were more precisely distinguished from adrenal metastases on T2*-weighted images (21 of 23, 91%) than on T2-weighted images (15 of 23, 65%). T1-weighted images were not useful for this distinction. In conclusion, T2*-weighted images were better than routine T2-weighted images for distinguishing adrenal adenomas from adrenal metastases. It can be postulated that the total signal intensity of adrenal adenomas, which contain some fat components, decreased on T2*-weighted images because of an out-of-phase effect.     

MR angiography of congenital heart disease: Value of segmented two-dimensional inflow technique and maximum-intensity-projection display

Magnetic resonance (MR) angiography of the cardiovascular system was evaluated in 41 patients with congenital heart disease by using a two-dimensional (2D) inflow technique based on a magnetization-prepared gradient-echo pulse sequence with segmented k-space data acquisition and electrocardiographic gating at 0.5 T. Inversion and saturation prepulses were used to suppress stationary tissue and enhance intravascular signal. Presaturation slabs were applied where certain vascular structures had to be suppressed. Sequence parameters were optimized by evaluating signal intensity and contrast characteristics for various flip angles and inversion and saturation delay times. The heart and intrathoracic vasculature were encompassed with 40–50 overlapping sections. Both 2D angiograms and maximum-intensity-projection images were evaluated. Combining data sets acquired in the sagittal and transverse orientations provided the most satisfactory information about the pulmonary arteries. The highest signal-to-noise ratios were obtained with a flip angle of 65° and short prepulse delay times. Two-dimensional MR angiography can provide useful diagnostic information but requires a thorough understanding of in-plane and hemodynamically induced signal intensity changes.