乙交酯-丙交酯共聚物-细胞复合体移植治疗脊髓损伤

目的:观察神经干细胞、许旺细胞和组织工程支架材料乙交酯-丙交酯共聚物于大鼠髓内共移植后的生物相容性,及其对大鼠损伤脊髓形态和功能的修复作用。方法:实验于2005-05/2006-09在首都医科大学附属北京市神经外科研究所损伤修复实验室完成。①实验材料:健康成年雌性Wistar大鼠36只,随机数字表法分为单纯支架组、神经干细胞 支架复合体组、神经干细胞 许旺细胞 支架复合体组,12只/组。乙交酯-丙交酯共聚物由中科院化学研究所医用高分子材料中心提供。②实验方法:各组大鼠均建立脊髓T9半横断损伤模型。神经干细胞 许旺细胞 支架复合体组取2×1010L-1的许旺细胞、神经干细胞各10μL接种于乙交酯-丙交酯共聚物支架内,神经干细胞 支架复合体组取2×1010L-1的神经干细胞10μL接种于乙交酯-丙交酯共聚物支架内,单纯支架组取10μLDMEM培养液置于乙交酯-丙交酯共聚物支架内,于脊髓缺损处分别植入对应的复合物。③实验评估:应用电镜观察乙交酯-丙交酯共聚物支架的降解及轴突的再生状况;应用BBB评分和电生理技术检测大鼠脊髓功能性的恢复情况。结果:36只Wistar大鼠均进入结果分析。①行为学观察结果:移植术后4,12周,神经干细胞 支架复合体组、神经干细胞 许旺细胞 支架复合体组大鼠的后肢运动功能BBB评分均好于单纯支架组(P<0.01),其中神经干细胞 许旺细胞 支架复合体组尤为明显。②神经电生理检查结果:在脊髓半横断损伤后即刻,所有动物的体感诱发电位和运动诱发电位波幅都明显减低甚至消失。移植术后4周,神经干细胞 支架复合体组、神经干细胞 许旺细胞 支架复合体组大鼠的体感诱发电位和运动诱发电位波幅均有所恢复;至移植术后12周恢复明显。单纯支架组移植术后4,12周体感诱发电位和运动诱发电位波幅无明显变化。③电镜观察结果:扫描电镜下,随着时间的延长各组植入的乙交酯-丙交酯共聚物逐渐降解。透射电镜下,各组植入材料正中横断面可见新生的无髓及有髓神经纤维,至12周时神经干细胞 许旺细胞 支架复合体组最明显。结论:乙交酯-丙交酯共聚物在大鼠损伤的脊髓内具有良好的生物相容性;其与神经干细胞、许旺细胞共移植能够明显促进脊髓半横断损伤大鼠的脊髓轴突再生,并改善肢体的运动功能。     

血管紧张素原基因5’端启动子区A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压的相关性

目的:分析血管紧张素原基因启动子区A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压的相关性。方法:实验于2005-08/2006-01在北京华大实验室完成。选取对象均为生活在内蒙古乌拉特后旗的蒙古族牧民,三代血亲内无其他民族。采用基因测序技术对内蒙古蒙古族人群中107例原发性高血压患者和108例正常对照者进行A-20C和A-6G基因分型,观察高血压组和正常对照组不同基因型的分布和等位基因频率的差异。结果:①两组受试者在性别、年龄及吸烟、饮酒、体质量指数和临床化验检查指标有较好的匹配(P均>0.05)。②两组血管紧张素原基因A-20C位点AA,AC,CC基因型频率比较差异无显著性意义(高血压组分别为0.51,0.29,0.20;正常对照组分别为0.49,0.28,0.23,χ2=0.395,P=0.529)。A,C等位基因频率比较差异无显著性意义(高血压组分别为0.65,0.35;正常对照组分别为0.63,0.37,χ2=0.015,P=0.904)。③两组血管紧张素原基因A-6G位点AA,AG,GG基因型频率比较差异无显著性意义(高血压组分别为0.50,0.33,0.17;正常对照组分别为0.55,0.34,0.11,χ2=1.924,P=0.165)。A,G等位基因频率比较差异无显著性意义(高血压组分别为0.66,0.34;正常对照组分别为0.72,0.28,χ2=1.728,P=0.189)。④高血压组协同存在血管紧张素原基因A-20C基因型CC时,血管紧张素原基因A-6G基因型GG频率稍高于正常对照组,但差异无显著性意义(χ2=2.395,P=0.122,OR=7.52,95%CI0.014～1.250),高血压组G等位基因明显高于正常对照组(分别为0.37,0.22,χ2=4.658,P=0.034),携带该等位基因的蒙古族人群发生原发性高血压的相对危险度升高(OR=2.80,95%CI1.087～7.271)。结论:血管紧张素原基因A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压相关,并可能具有协同作用。     

Red cell alloimmunization in multitransfused HLA-typed patients

The authors studied retrospectively the formation of clinically significant red cell (RBC) alloantibodies in 958 HLA-typed, multiply transfused patients receiving kidney (603 patients) or liver (263 patients) transplants or plateletpheresis transfusions (92 patients). RBC alloantibodies were found in 91 (9.5%) of these patients and multiple antibodies in 35 (3.7%). Rh (D, C, c, and E) antibodies accounted for 49 percent of the total and Kell antibodies for 31 percent. Antibodies were found in 15 percent of apheresis recipients and in 8.6 percent of renal and 9.5 percent of liver transplantation patients. No association was found between any HLA-A, HLA-B, or HLA-DR phenotype and the presence of RBC alloantibodies, either in general or when analyzed according to the specific antibody. Renal transplant patients with RBC alloantibodies were somewhat more broadly HLA-alloimmunized than were those without RBC alloantibodies. Patient gender did not affect these results. The authors concluded that the immune response to RBC alloantigens is independent of HLA type but is associated with an increased level of HLA antibody formation.     

Interleukin-1 alpha upregulates tumor necrosis factor receptors expressed by a human bone marrow stromal cell strain: implications for cytokine redundancy and synergy

To explore the biochemical and physiologic basis of the overlapping effects of interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor alpha (TNF-alpha) on myeloid cytokine production, we have studied the dynamics of granulocyte colony-stimulating factor (G-CSF) and granulocyte-monocyte colony-stimulating factor (GM-CSF) production as well as IL-1 receptor and TNF receptor expression in a clonally derived bone marrow stromal cell strain (CDCL). IL-1 alpha and TNF alpha act in a synergistic manner to stimulate G-CSF and GM-CSF production by CDCL, resulting in an increase in CSF secretion that is 250-fold greater than that observed with either cytokine alone. This synergism in protein secretion is paralleled by synergistic increases the steady-state level of GM- and G-CSF mRNA, with supra-additive levels achieved by 24 hours. Coincident with this synergistic induction of myeloid CSFs, treatment of CDCL cells with IL-1 alpha induces a 300% increase in the expression of TNF receptors. IL-1 alpha induction of TNF receptors reaches a peak after 6 hours and gradually returns to baseline level by 24 hours. IL-1 alpha does not affect TNF receptor ligand binding affinity. A kinetic study comparing IL-1/TNF synergistic induction of growth factor secretion with IL-1 alpha induction of TNF receptors shows that these events occur in parallel. In contrast with the induction of TNF receptors by IL-1 alpha, treatment with TNF alpha has no effect on either the number of IL-1 receptors expressed by CDCL cells or IL-1 receptor ligand binding affinity. Brief treatment of IL-1 alpha/TNF alpha-stimulated CDCL cells with cycloheximide before receptor induction reduces the synergistic increase in growth factor mRNA by 40% to 60% compared with cells not treated with CHX. Taken together, these results raise the possibility that IL-1 alpha cross-induction of TNF receptors may contribute to the biochemical mechanisms underlying the synergistic stimulation of G-CSF and GM-CSF production by IL-1 alpha and TNF alpha.     

Effect of flow on polymorphonuclear leukocyte/endothelial cell adhesion

The effect of flow on the adhesion of polymorphonuclear leukocytes (PMNL) to vascular endothelium was investigated using a parallel plate chamber with a well-defined flow field. Washed PMNL were perfused over a monolayer of primary human umbilical vein endothelial cells (HUVEC) pretreated with formyl-methionyl-leucyl-phenylalanine (FMLP, 1 X 10(-7) mol/L) for five minutes. In other experiments HUVEC were pretreated with interleukin 1 (IL1,2 U/mL) for four hours. PMNL adhesion to stimulated and control HUVEC was measured over a physiologic range of wall shear stresses. PMNL adhesion to nylon-coated surface was also studied. At a wall shear stress of 0.98 dynes/cm2,283 +/- 37.3 PMNL/mm2 (mean +/- SEM) adhered to FMLP-treated HUVEC while 195 +/- 20.3 PMNL/mm2 adhered to control HUVEC. At 1.96 dynes/cm2, 68 +/- 14.1 PMNL/mm2 adhered to FMLP-treated HUVEC and 42 +/- 6.0 PMNL/mm2 adhered to control HUVEC. At 3.92 dynes/cm2, virtually no PMNL adherence was noted on either control or FMLP-treated HUVEC. On IL 1-treated HUVEC at 1.96 dynes/cm2, 371 +/- 25.8 PMNL/mm2 adhered while 28 +/- 2.9 PMNL/mm2 adhered to control HUVEC. PMNL adhesion to IL 1-treated and control HUVEC dropped to 10.2 +/- 3.8 and 6.8 +/- 3.5 PMNL/mm2, respectively, at 3.01 dynes/cm2. The effect of flow on PMNL adhesion appears to be an important factor in determining the outcome of the PMNL/HUVEC adhesive interaction under these experimental conditions.