Identification of a growth factor for primary murine stroma as macrophage colony-stimulating factor

Knowledge of the stromal microenvironment is crucial for understanding the hematopoietic system. We took advantage of an assay that permits analysis of primary stroma-initiating cells (SICs) on the clonal level, and further characterized SICs and the factors that regulate SICs. Stroma formation in this assay is dependent on a high-molecular-weight factor secreted by the stromal cell line AC3.U. Here we show that this factor is identical to macrophage colony-stimulating factor (M-CSF), and that purified M-CSF is sufficient for induction of stroma formation. M-CSF, isolated from the line AC3.U, as well as from L929 cells and COS cells transfected with an expression vector encoding M- CSF, migrated in two peaks as 160- and 650-kD species after gel filtration. These molecular-weight species encompassed all stroma- inducing activity, and both stimulated macrophage colony formation. Affinity chromatography and blocking studies with antibodies specific for M-CSF and c-fms confirmed M-CSF as the sole factor in the supernatant of the stromal cell line AC3.U that promotes stroma formation. Culture of marrow, for as little as 1 week, depleted M-CSF- dependent SIC while increasing the incidence of replatable, factor- independent SIC. This suggests that culture changes the properties of SICs, perhaps by inducing differentiation into mature stromal cells. Thus, our results show a novel function of M-CSF as an important modulator of stroma formation.     

人sTRAIL基因的克隆、表达纯化及对人A549细胞的抗肿瘤活性作用

目的人TRAIL基因胞外区片段(114-281氨基酸残基,sTRAIL)的克隆、表达、纯化及对人肺腺癌A549细胞的抗肿瘤活性研究。方法采用PCR技术从人胎盘和肺cD-NA文库中扩增出全长人TRAIL基因,克隆到pUC19质粒载体上进行测序。然后再采用PCR技术,以全长人TRAIL基因为模板,扩增出sTRAIL基因片段并定向克隆到pET-11 a表达载体中,转化大肠杆菌BL21进行表达。表达后的产物经变性、复性和分离纯化,纯化后的sTRAIL用结晶紫染色法和流式细胞仪法测定其对人肺癌细胞A549的细胞毒性作用。结果从人胎盘和肺cDNA文库中都能扩增出全长人TRAIL基因,经测序表明与已发表的人TRAIL基因序列一致。扩增出的人sTRAIL基因克隆到表达质粒载体pET-11a,经IPTG诱导表达,表达量占细菌全菌蛋白的50%,纯化后的sTRAIL纯度大于98%,结晶紫法测定对人A549肺癌细胞的细胞毒性作用的IC50为(24±5.2)μg.L-1,流式细胞仪法测定对人A549肺癌细胞的细胞毒性具有明显的效应-时间依赖关系。结论本实验成功地克隆了人sTRAIL基因并实现其高表达,摸索出包涵体sTRAIL的变性、复性及其纯化方法,纯化后的sTRAIL蛋白对人A549肺癌细胞具有明显的细胞毒性作用,为进一步研究其功能与临床应用奠定了基础。     

Monoclonal antibody 7G3 recognizes the N-terminal domain of the human interleukin-3 (IL-3) receptor alpha-chain and functions as a specific IL-3 receptor antagonist

The human interleukin-3 receptor (IL-3R) is expressed on myeloid, lymphoid, and vascular endothelial cells, where it transduces IL-3- dependent signals leading to cell activation. Although IL-3R activation may play a role in hematopoiesis and immunity, its aberrant expression or excessive stimulation may contribute to pathologic conditions such as leukemia, lymphoma, and allergic reactions. We describe here the generation and characterization of a monoclonal antibody (MoAb), 7G3, which specifically binds to the IL-3R alpha-chain and completely abolishes its function. MoAb 7G3 immunoprecipitated and recognized in Western blots the IL-3R alpha-chain expressed by transfected cells and bound to primary cells expressing IL-3R alpha. MoAb 7G3 bound the IL-3R alpha-chain with a kd of 900 pmol/L and inhibited 125I-IL-3 binding to high- and low-affinity receptors in a dose-dependent manner. Conversely, IL-3 but not granulocyte-macrophage colony-stimulating factor (GM-CSF) inhibited 125I-7G3 binding to high- and low-affinity IL- 3Rs, indicating that MoAb 7G3 and IL-3 bind to common or adjacent sites. In keeping with the inhibition of IL-3 binding, MoAb 7G3 antagonized IL-3 biologic activities, namely stimulation of TF-1 cell proliferation, basophil histamine release, and IL-6 and IL-8 secretion from human endothelial cells. Two other anti-IL-3R alpha-chain MoAbs failed to inhibit IL-3 binding or function. Epitope mapping experiments using truncated IL-3R alpha-chain mutants and IL-3R alpha/GM-CSFR alpha chimeras revealed that 31 amino acids in the N-terminus of IL-3R alpha were required for MoAb 7G3 binding. MoAb 7G3 may be of clinical significance for antagonizing IL-3 in pathologic conditions such as some myeloid leukemias, follicular B-cell lymphoma, and allergy. Furthermore, these results implicate the N-terminal domain of IL-3R alpha in IL-3 binding. Since this domain is unique to the IL-3/GM- CSF/IL-5 receptor subfamily, it may represent a novel and common binding feature in these receptors.     

低频重复经颅磁刺激在帕金森病中的康复治疗作用

目的　探讨低频重复经颅磁刺激 (rTMS)对帕金森患者的治疗效果。方法　对 3 5例帕金森病 (PD)患者予以低频rTMS治疗 ,以 60 %最大刺激强度刺激双侧额叶 ,每侧刺激 3 0次 ,频率 0 .5Hz,每日 1序列 ,连续治疗共 7次为 1个疗程。于治疗前、后观察WPDEF评分、汉密尔顿抑郁分级量表 (HAMD)及中枢静止期 (CSP)等指标变化 ,评估rTMS在PD康复及治疗中的作用。结果　低频rTMS治疗后WPDEF评分减少 (P <0 .0 1)。TMS CSP延长 ,HAMD降低 (P <0 .0 5) ,其差异具有显著性。治疗的近期总有效率为 86% ,远期效果有待进一步观察。结论　低频rTMS治疗在减轻PD主要临床症状的同时也能改善其伴随的抑郁状态 ,适用于PD的康复辅助治疗 ;其作用机理为低频rTMS可能增强皮质内抑制而延长CSP ,促进多巴胺的释放 ,以及改善PD伴随的抑郁心境     

应用螺旋CT技术重建桩核体三维数字模型的可行性研究

目的构建桩核体的三维数字模型(库),为个体化桩核的设计、制作提供基础条件。方法在标准模型上制备桩核体的模板,采用螺旋CT扫描对其进行测量,应用Mimics软件和Geomagic 9.0软件实现桩核体的三维实体化重建,对桩核体模板表面标志点间距离进行相应的软件测量,并进行统计学分析。结果用螺旋CT扫描数据对桩核体的模板实现了三维实体化重建,获得桩核体的三维数字模型(库)。螺旋CT扫描数据所建立的桩核体三维数字模型,边缘轮廓连续、平滑,肩台清晰可辨。软件测量组和实体测量组桩核体模板表面标志点间距离的差异无统计学意义(t=0.158,P=0.876)。结论应用螺旋CT扫描数据,能够准确、快速建立桩核体的三维数字模型(库),软件测量与实体模型的测量值高度相关,系统与常用的测量手段间具有较好的一致性,该数字模型(库)能直接用来进行桩核的计算机辅助设计。     

Extraadrenal pheochromocytoma: detection during pregnancy using MR imaging

This case report demonstrates the usefulness of magnetic resonance (MR) imaging to demonstrate an abdominal mass during pregnancy. A pregnant woman presented in midgestation with symptoms and chemical evidence of a pheochromocytoma. The use of MR imaging permitted early localization of a retrouterine tumor when it would have been undesirable for the woman to undergo computed tomography because of radiation exposure. Evaluation of the MR images formed the basis of the therapeutic strategy used by the patient's physicians.     

Fibrinogen binding to human blood platelets: effect of gamma chain carboxyterminal structure and length

Recent evidence suggests that fibrinogen binding to platelets is mediated by the 12 carboxyterminal amino acid residues of the gamma chain. Because human plasma fibrinogen gamma chains differ in mol wt and carboxyterminal amino acid sequence, we examined the effect of such gamma chain heterogeneity on platelet-fibrinogen interactions, using two fibrinogens of distinct composition, separated by ion exchange chromatography. One fibrinogen possessed only gamma chains of mol wt 50,000 (F gamma 50), the predominant gamma chain species found in plasma. The other fibrinogen possessed equal amounts of gamma chains with mol wt 50,000 and 57,500 (F gamma 50,57.5), with the longer gamma chain (gamma 57.5) possessing an amino acid extension at the carboxyterminal end. The latter fibrinogen was 50% less effective than F gamma 50 in supporting ADP-induced platelet aggregation at concentrations of .01 to 2 mg/mL. Scatchard analysis revealed no difference in the binding affinities of the two fibrinogens to ADP- treated platelets, but the amount of F gamma 50,57.5 that was bound to platelets at saturation was only 50% that of F gamma 50. Fibrinogen receptors that remained unoccupied in the presence of saturating concentrations of F gamma 50,57.5, however, could be occupied by fresh F gamma 50. Excess unlabeled F gamma 50 displaced both radiolabeled fibrinogens from activated platelets, and both fibrinogens bound to the same platelet receptor, as judged by the inhibition of binding to stimulated platelets by a monoclonal antibody directed against the glycoprotein (GP) IIb/IIIa complex. Furthermore, an intact GPIIb/IIIa complex was required for these reactions, since platelets incubated with EDTA at 37 degrees C at alkaline pH failed to aggregate and bound neither fibrinogen in response to ADP following recalcification. Approximately 50% of each fibrinogen bound irreversibly to platelets after one hour and failed to dissociate in the presence of 10 mmol/L of EDTA or excess unlabeled F gamma 50. The data demonstrate that heterodimeric F gamma 50,57.5 binds less well to platelets and supports platelet aggregation only half as well as homodimeric F gamma 50. These results support prior conclusions that the carboxyterminal portion of the gamma chain is important in platelet-fibrinogen interactions, and suggest that the 20 amino acid, hydrophobic gamma chain carboxyterminal extension of F gamma 50,57.5 may sterically hinder the interaction of this fibrinogen with platelet receptors.     

B 超诊断前置胎盘分型的再探讨

目的 对Ｂ超诊断前置胎盘分型的改进探讨。方法 对３６例前置胎盘患者进行Ｂ超探查。观察胎盘下缘与子宫内口的关系。结果 前置胎盘的Ｂ超声像图可分四类：①胎盘中央部位于宫内口。②胎盘边缘部完全覆盖宫内口。③胎盘下缘至宫内口边缘,未覆盖宫内口。④盈盘位于子宫下截,未达到宫内口。结论 部分性前置胎盘的超声诊断分型担法不确切可予取消。将中央性前置胎盘诊断分两个亚型：中央型、边缘型。