弦式加载法延长面神经模型的建立

目的　为使神经延长术更简便地应用于临床 ,尤其是用于面神经缺损的修复 ;同时更科学地研究周围神经的生物力学特性。方法　自行研制一种新的神经延长器 ,以弦式加载方式对面神经进行快速和缓慢延长 ,观察延长前后面神经的电生理及病理形态学变化。结果　延长器放置部位的组织无变性坏死 ,伤口及创面无感染 ,动物进食功能无障碍 ,体温不升高 ;病理学观察可见快速组神经出现散在的 Sunderland 度损伤 ,偶见毛细血管断裂 ,而缓慢组神经变粗 ,神经束间、外膜成纤维细胞增生 ;颊肌肌电图及神经传导速度检测显示 ,神经可延长极限快速组为 (18.7± 2 .4) % ,缓慢组为 (30 .8± 2 .4) % (均已除去回缩率 )。结论　所建立的神经延长模式和方法具有科学性和实用性 ,可用于神经延长的基础和临床研究。     

三氧化二砷对慢性髓系白血病细胞周期及Survivin表达的影响

目的研究三氧化二砷(As2O3)对慢性髓系白血病细胞(K562)的作用特点及其机制。方法不同浓度As2O3作用于K562细胞后，四唑盐(MTT)比色法分析细胞增殖；流式细胞术检测细胞周期分布、细胞凋亡及Survivin抗原表达；RT-PCR检测Survivin mRNA的表达。结果2—10μmoL／L的As2O3能有效抑制K562细胞增殖，但未能诱导明显的细胞凋亡。周期分析显示，G2／M期细胞比例显著增多；同时G2／M细胞周期依赖性表达的Survivin mRNA和蛋白表达增加。结论As2O3明显抑制K562细胞的生长，其机制是诱导G2／M期细胞周期停滞。Survivin表达上调可能是K562细胞对As2O3诱导凋亡抵抗的机制之一。     

Role of CD56-expressing immature biliary epithelial cells in biliary atresia

AIM: To analyze the clinical and pathological parameters and expression of the neural cell adhesion molecule(CD56) in patients with biliary atresia(BA).METHODS: Established clinical laboratory markers of hepatic function, including enzyme activity, protein synthesis, and bilirubin metabolism, were evaluated in patients with BA and compared with those in patients with choledochal cysts and neonatal hepatitis. Pathological changes in tissue morphology and fibrosis were examined by histological and tissue collagen staining. Immunohistochemical staining for the biliary epithelial cell markers CD56 and CK19 together with the Notch signaling related molecules Notch1 and Notch2 was performed in the context of alterations in the structure of intrahepatic biliary ducts.RESULTS: Differences in some clinical laboratoryparameters among the three diseases examined were observed, but they did not correlate with the pathological classification of fibrosis in BA. Immunohistochemical staining showed the presence of CD56-positive immature bile ducts in most patients(74.5%) with BA but not in patients with choledochal cysts or neonatal hepatitis. The number of CD56-expressing cells correlated with disease severity, with more positive cells present in the later stages of liver damage(81.8% vs 18.2%). Furthermore, bile plugs were mainly found in CD56-positive immature biliary ducts. Notch signaling was a key regulatory pathway in biliary duct formation and played a role in tissue fibrosis. Notch1 was co-expressed in CD56-positive cells, whereas Notch2 was found exclusively in blood vessels in the portal area of patients with BA. CONCLUSION: The maturation of biliary epithelial cells and the expression of Notch may play a role in the pathogenesis of BA.     

肌萎缩侧索硬化症磁共振扩散张量成像与临床相关性分析

目的:探讨肌萎缩侧索硬化症(ALS)磁共振扩散张量成像(DTI)结果与临床的相关性,从而为ALS的早期诊断提供可能的客观依据.方法:对16例ALS患者和15例健康志愿者行常规颅脑MRI扫描,均加扫轴面DTI序列.选取内囊后肢后3/4为兴趣区(ROI),测量各向异性分数(FA)和平均扩散系数(ADC),研究各临床指标(包括年龄、病程、ALS功能评分、病情进展速度)与FA值、ADC值的相关性.结果:在内囊后肢水平,ALS组FA值明显低于对照组 (t=3.452,P=0.002),ADC值明显高于对照组(t=2.670,P=0.012).内囊后肢FA值与ALS功能评分正相关(r=0.577,P=0.019),与年龄、病程、病情进展速度均无相关性(P＞0.05);内囊后肢ADC值和年龄、病程、ALS功能评分、病情进展速度均无相关性(P＞0.05).结论:ALS患者内囊后肢FA值和ADC值变化明显,前者更显著;FA值与ALSFRS评分呈正相关,提示FA值是评价上运动神经元损害更敏感指标,因此可为肌萎缩侧索硬化症诊断提供有价值信息,并在准确评估ALS患者治疗疗效、预后方面有着良好的应用前景.     

Tailoring immunosuppressive therapy for renal transplant recipients

During the past decade several new potent immunosuppressive agents with different modes of action and different side-effect profiles have become available. Nowadays immunosuppression after renal transplantation is no longer one single regimen applicable to all patients. In the selection of the optimal immunosuppressive protocol, individual drug-related toxicity, recipient-related risk factors as well as donor organ characteristics have to be taken into account. This article will give an overview of the most recently developed immunosuppressive agents available for clinical use. Their individual mode of action and their different efficacy and safety profile will be described as basis for selection of each of these drugs in an attempt to tailor the optimal therapeutic regimen for the individual patient both in terms of short-term and long-term outcome.     

Interaction Between B.7 and CD28 Costimulatory Molecules is Essential for the Activation of Effector Function Mediating Spontaneous Tumour Regression

The spontaneous regression of a rat histiocytoma, AK-5, is mediated by activated natural killer cells through antibody-dependent cellular cytotoxicity. In addition to the Fc-FcR interaction between the target and the effector cells demonstrated previously, we show the participation of costimulatory molecules B7 and CD28 in the efficient killing of the tumour cell. Blockade of the costimulatory interaction in vivo using anti-CD28 led to increased tumour growth and a suppressed cytokine response. Anti-CD28 antibody administration in vivo also diminished the cytotoxic potential of NK cells against AK-5 cells in vitro. Our studies also demonstrate the expression of B7.1 and B7.2 antigen on AK-5 tumour cells. The cytotoxic activity of natural killer cells was significantly inhibited when the effector/target cells were cultured in the presence of antibodies raised against B7.1, B7.2 and CD28. Administration of anti-CD28 in vivo also affected the efficiency of the formation of effector/target conjugates in vitro. Similarly, anti-CD28 injections affected expression of the adhesion molecules LFA 1 and ICAM 1 by splenocytes. Administration of anti-B7.1 and B7. 2 antibodies in AK-5 tumour-bearing animals showed a differential response. The cytotoxicity of natural killer cells was significantly inhibited after anti-B7.2 administration, suggesting the preferential participation of B7.2 molecules in vivo. These observations suggest an important role for B7-CD28 interaction in AK-5 tumour regression.