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目的:以鸭γ-干扰素(DuIFN-γ)基因为目的基因,研究同一启动子调控下,不同拷贝数的目的基因的表达状况。方法:采用基因重组技术构建含DuIFN-γcDNA单拷贝和双拷贝重组质粒并转入真核细胞COS-7中进行表达。DuIFN-γ活性采用Griess试剂检测。结果:双拷贝重组质粒和单拷贝重组质粒50%最大活性稀释度分别为1:320和1:160。双拷贝重组质粒转染上清稀释10240倍后,仍保留DuIFN-γ活性,而单拷贝重组质粒转染上清经1280倍稀释后,即丧失活性。结论:在同一启动子作用下,顺式插入双拷贝目的基因可明显增强目的基因在真核细胞中的表达量。  相似文献   
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Meningeal melanocytomas are rare pigmented tumors of the central nervous system. These tumors are benign melanotic lesions that derive from the melanocytes of the leptomeninges. They may occur anywhere in the cranial and spinal meninges; however, they are found prevalently in the posterior fossa and in the spinal cord. Their epidemiological features, natural history and response to treatment remain poorly understood, even if, in the last 2 years, some reviews have been published about it. We report a new case of intracranial supratentorial meningeal melanocytoma, in the temporal lobe, occurring in a 27-year-old man, admitted to our Institute with a long-time history of seizures. We report histological and radiological characteristics of our case, and briefly review the therapeutical options reported in literature. Preoperative neuroradiological finding is unclear; the preoperative diagnosis is usually meningioma, because of the long duration of symptomatology and the radiological appearance of the lesion as an extra-axial mass. Diagnosis of these lesions, as in our case, is made intraoperatively by the gross, jet-black appearance of the tumor and by histological examination. In spite of the benign biologic behaviour, the prognosis remains uncertain, because of the possible local recurrences. According to the results of some works of the last years, it seems appropriate to use postoperative radiotherapy for those patients with symptomatic residual, progressive or recurrent tumors not amenable to further resection.  相似文献   
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从鸭外周血分离的单核细胞在体外经PHA (5 μg/ml)刺激 2 0h后 ,提取总RNA及mRNA并通过逆转录制备cDNA。采用最近克隆的鸡白细胞介素 2 (ChIL 2 )cDNA序列为探针对cDNA进行Southernblot杂交 ,以识别鸭白细胞介素 2 (DuIL 2 )特异的cDNA序列。从鸭外周血单核细胞中提取的基因组DNA经限制性内切酶BamHI、EcoRI、XbaI消化后 ,以上述探针进行杂交 ,分析DuIL 2基因组序列。结果表明 ,无论是鸭cDNA或基因组DNA ,经Southern杂交后 ,均得到特异性杂交条带 ,证实ChIL 2与DuIL 2具有较高序列同源性。DuIL 2mRNA表达时形成两种转录子 ,大小分别为 95 9bp、 780bp。同鸡γ 干扰素(ChIFN γ )探针产生的杂交信号比较 ,ChIL 2产生的杂交信号相对较弱 ,推测可能和DuIL 2mRNA在上述条件下拷贝数相对较少以及ChIL 2与DuIL 2cDNA序列同源性相对较低有关  相似文献   
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Minimally invasive surgery to the posterolateral craniovertebral junction (CVJ) has not been sufficiently described. The aims of this study were to evaluate the feasibility of an endoscopic far-lateral approach to the posterolateral craniocervical junction and to better understand the related anatomy under distorted endoscopic view. Ten fresh cadavers were studied with 4-mm 0° and 30° endoscopes to develop the surgical approach and to identify surgical landmarks. After making a 3-cm straight incision behind the mastoid process, the superior oblique and rectus capitis posterior major muscles were partially exposed. An endoscope was then introduced and the two muscles were followed inferiorly until the posterior arch of the atlas appeared. The two muscles were removed to create ample working space without violating the posterior atlanto-occipital membrane. The vertebral artery was identified by the landmark of the posterior arch of the atlas, and the atlanto-occipital joint and foramen magnum were exposed. In addition to suboccipital craniectomy, transcondylar, supracondylar, and paracondylar extension by drilling were applicable through the narrow corridor under superb visualization. The intradural neurovascular structures from the acousticofacial bundle to the dorsal root of C2, anterolateral space of the foramen magnum, cerebellomedullary fissure, and fourth ventricle were clearly demonstrated. This endoscopic far-lateral approach offers excellent exposure of surgical landmarks around the posterolateral CVJ with minimal invasiveness. Endoscopic soft tissue dissection is key to creating the surgical corridor. This approach could offer an alternative to the conventional far-lateral approach in selected cases.  相似文献   
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Heart failure (HF) is a common, serious chronic condition with high morbidity, hospitalisation and mortality. The healthcare systems of England and the northern Italian region of Lombardy share important similarities and have comprehensive hospital administrative databases linked to the death register. We used them to compare admission for HF and mortality for patients between 2006 and 2012 (n = 37,185 for Lombardy, 234,719 for England) with multistate models. Despite close similarities in age, sex and common comorbidities of the two sets of patients, in Lombardy, HF admissions were longer and more frequent per patient than in England, but short- and medium-term mortality was much lower. English patients had more very short stays, but their very elderly also had longer stays than their Lombardy counterparts. Using a three-state model, the predicted total time spent in hospital showed large differences between the countries: women in England spent an average of 24 days if aged 65 at first admission and 19 days if aged 85; in Lombardy these figures were 68 and 27 days respectively. Eight-state models suggested disease progression that appeared similar in each country. Differences by region within England were modest, with London patients spending more time in hospital and having lower mortality than the rest of England. Whilst clinical practice differences plausibly explain these patterns, we cannot confidently disentangle the impact of alternatives such as coding, casemix, and the availability and use of non-hospital settings. We need to better understand the links between rehospitalisation frequency and mortality.  相似文献   
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