生长因子及其受体在淋巴瘤中异常表达的研究进展

生长因子是一类与受体结合后可以促进细胞增殖和调节细胞多项功能的多肽分子。生长因子及其受体信号通路包括Ras/MAPK、PI3K/AKT和STAT等不仅调控正常细胞的生物学行为,对恶性肿瘤细胞增殖、分化、转化和迁移也具有重要意义。研究发现多种生长因子如VEGF、PDGF和IGF及其受体在多种实体肿瘤如肺癌、乳腺癌、结肠癌中发现有异常表达,在淋巴瘤如DLBCL、PTCL、ML和NL中也存在异常的共同表达,提示在淋巴瘤中可能构成生长因子及其受体的自分泌/旁分泌环路。生长因子及其受体的表达对淋巴瘤患者的预后有一定指导意义,临床研究发现表达生长因子或其受体阳性患者比表达阴性患者有较差的临床预后。这可能与生长因子及其受体对淋巴瘤细胞的增殖、转移和耐药调控有关。目前生长因子及其受体已成为潜在的药物靶点,多种生长因子及其受体抑制剂在开发和临床试验中。本文就近年来生长因子及其受体在淋巴瘤中异常表达研究进展作简要综述。     

Neurotrophic factors for the treatment of Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disorder caused by the progressive degeneration of the nigrostriatal dopaminergic pathway. The resulting loss of dopamine neurotransmission is responsible for the symptoms of the disease. Available treatments are initially successful in treating PD symptoms; however, their long-term use is associated with complications and they cannot stop the neurodegeneration. Current research aims at developing new therapies to halt/reverse the neurodegenerative process, rather than treating symptoms. Neurotrophic factors are proteins critical for maintenance and protection of neurones in the developing and adult brain. Several neurotrophic factors have been investigated for their protective effects on dopaminergic neurones. Here we review some of the most promising factors and provide an update on their status in clinical trials.     

NGF and the local control of nerve terminal growth

It is generally believed that the mechanism of action of neurotrophic factors involves uptake of neurotrophic factor by nerve terminals and retrograde transport through the axon and back to the cell body where the factor exerts its neurotrophic effect. This view originated with the observation almost 20 years ago that nerve growth factor (NGF) is retrogradely transported by sympathetic axons, arriving intact at the neuronal cell bodies in sympathetic ganglia. However, experiments using compartmented cultures of rat sympathetic neurons have shown that neurite growth is a local response of neurites to NGF locally applied to them which does not directly involve mechanisms in the cell body. Recently, several NGF-related neurotrophins have been identified, and several unrelated molecules have been shown to act as neurotrophic or differentiation factors for a variety of types of neurons in the peripheral and central nervous systems. It has become clear that knowledge of the mechanisms of action of these factors will be crucial to understanding neurodegenerative diseases and the development of treatments as well as the means to repair or minimize neuronal damage after spinal injury. The concepts derived from work with NGF suggest that the site of exposure of a neuron to a neurotrophic factor is important in determining its response. 1994 John Wiley & Sons, Inc.     

医患关系困境的制度影响因素及策略分析

目的 从制度角度探讨医患关系恶化的原因,并给出制度角度上具体的实施建议。方法 运用文献研究法及专题小组讨论法得出医患关系的制度影响因素集合,根据问卷调查结果进行因子分析研究。结果 医患关系深深嵌入到复杂的社会制度体系中,制度、道德文化、目标等八个领域决定医患关系和谐程度,基于因子分析结果,投入制度、强制约束制度和运行与管理制度是医患关系问题的深层制度根源。结论 通过立法建立可持续投入机制,建立解决医患冲突的法律法规、仲裁机制和责任分担制度,采取分级诊疗分化医疗费用压力,加强制度手段对医患关系的统筹管理。     

How it all starts: Initiation of the clotting cascade

Abstract

The plasma coagulation system in mammalian blood consists of a cascade of enzyme activation events in which serine proteases activate the proteins (proenzymes and procofactors) in the next step of the cascade via limited proteolysis. The ultimate outcome is the polymerization of fibrin and the activation of platelets, leading to a blood clot. This process is protective, as it prevents excessive blood loss following injury (normal hemostasis). Unfortunately, the blood clotting system can also lead to unwanted blood clots inside blood vessels (pathologic thrombosis), which is a leading cause of disability and death in the developed world. There are two main mechanisms for triggering the blood clotting, termed the tissue factor pathway and the contact pathway. Only one of these pathways (the tissue factor pathway) functions in normal hemostasis. Both pathways, however, are thought to contribute to thrombosis. An emerging concept is that the contact pathway functions in host pathogen defenses. This review focuses on how the initiation phase of the blood clotting cascade is regulated in both pathways, with a discussion of the contributions of these pathways to hemostasis versus thrombosis.     

Acid-induced unfolding of the amino-terminal domains of the lethal and edema factors of anthrax toxin

The two enzymatic components of anthrax toxin, lethal factor (LF) and edema factor (EF), are transported to the cytosol of mammalian cells by the third component, protective antigen (PA). A heptameric form of PA binds LF and/or EF and, under the acidic conditions encountered in endosomes, generates a membrane-spanning pore that is thought to serve as a passageway for these enzymes to enter the cytosol. The pore contains a 14-stranded transmembrane beta-barrel that is too narrow to accommodate a fully folded protein, necessitating that LF and EF unfold, at least partly, in order to pass. Here, we describe the pH-dependence of the unfolding of LF(N) and EF(N), the 30kDa N-terminal PA-binding domains, and minimal translocatable units, of LF and EF. Equilibrium chemical denaturation studies using fluorescence and circular dichroism spectroscopy show that each protein unfolds via a four-state mechanism: N<-->I<-->J<-->U. The acid-induced N-->I transition occurs within the pH range of the endosome (pH 5-6). The I state predominates at lower pH values, and the J and U states are populated significantly only in the presence of denaturant. The I state is compact and has characteristics of a molten globule, as shown by its retention of significant secondary structure and its ability to bind an apolar fluorophore. The N-->I transition leads to an overall 60% increase in buried surface area exposure. The J state is expanded significantly and has diminished secondary structure content. We analyze the different protonation states of LF(N) and EF(N) in terms of a linked equilibrium proton binding model and discuss the implications of our findings for the mechanism of acidic pH-induced translocation of anthrax toxin. Finally, analysis of the structure of the transmembrane beta-barrel of PA shows that it can accommodate alpha-helix, and we suggest that the steric constraints and composition of the lumen may promote alpha-helix formation.     

Acute Regulation of the Epidermal Growth Factor Receptor in Response to Nerve Growth Factor

PC12 cells possess specific receptors for both nerve growth factor and epidermal growth factor, and by an unknown mechanism, nerve growth factor is able to attenuate the propagation of a mitogenic response to epidermal growth factor. The differentiation response of PC12 cells to nerve growth factor, therefore, predominates over the proliferative response to epidermal growth factor. We have observed that the addition of nerve growth factor to PC12 cells rapidly produces a decrease in surface 125I-epidermal growth factor binding capacity. Unlike previously described nerve growth factor effects on 125I-epidermal growth factor binding capacity, which required several days of nerve growth factor exposure, the decreases we report occur within minutes of nerve growth factor addition: A 50% decrease in 125I-epidermal growth factor binding capacity is evident at 10 min. This rapid nerve growth factor response is concentration dependent; inhibition of 125I-epidermal growth factor binding is detectable at nerve growth factor levels as low as 0.2 ng/ml and is maximal at approximately 50 ng/ml, consistent with known ranges of biological activity. No demonstrable differences in the rate of epidermal growth factor receptor synthesis or degradation were observed in cells acutely exposed to nerve growth factor. Scatchard analysis revealed that acute nerve growth factor treatment decreased the number of both high- and low-affinity 125I-epidermal growth factor binding sites, while the receptor affinity remained unchanged. We have also investigated the involvement of various potential intracellular mediators of nerve growth factor action and of known intracellular modulatory systems of the epidermal growth factor receptor for their capacity to participate in this nerve growth factor activity.     

Partial characterization of the cohemolytic factor produced by Streptococcus uberis and comparison with the CAMP-factor

Abstract Exosubstances (cohemolysins) produced by Streptococcus agalactiae (CAMP-factor) and Streptococcus uberis (Uberis-factor) showing hemolytic synergism with β-lysin produced by Staphylococcus aureus were compared. Cohemolytic activity was evaluated in the supernatants of bacterial cultures, before and after ammonium sulfate precipitation. Sheep erythrocytes sensitized with β-lysin were used as substrate. The assays were performed in microtiter plates and results were expressed as cohemolytic units/ml. Maximum cohemolytic activity was detected, respectively, after 8 h and 14 h of growth in Columbia broth in S. uberis and S. agalactiae cultures. Cohemolytic activities of both microorganisms showed similarities when submitted to various physical and chemical treatments. They were significantly decreased by heating at 60°C and 100°C, or in presence of trypsin, and were abolished in the presence of Tween 20. Activities were found to be stable in crude supernatants and concentrated preparations maintained at −20°C for 3 months. Differences were related to levels of activity and kinetics of detection during the growth cycle. The results indicate the proteic nature, at least in part, of the Uberis factor. Analysis by PAGE in the presence or absence of SDS allowed us to correlate Uberis activity with a protein band with apparent molecular mass of 42 kDa, while CAMP activity was associated with a protein band of 27 kDa.     

肿瘤坏死因子拮抗剂对强直性脊柱炎患者血清相关细胞因子变化的影响及其机制研究

目的:观察肿瘤坏死因子(TNF)拮抗剂对强直性脊柱炎(AS)患者血清中IL-6、IL-17、IL-21、IL-23、TNF-α、TGF-β1表达的影响,结合临床指标的变化探讨肿瘤坏死因子拮抗剂治疗AS的机制与疗效。方法:治疗组应用益赛普联合西乐葆,益赛普25 mg,皮下注射,连用8周,治疗前后评估晨僵VAS评分、腰背痛VAS评分、Bath强直性脊柱炎功能指数(BASFI)及血沉等指标,记录不良反应。用酶联免疫吸附法检测25例肿瘤坏死因子拮抗剂联合COX-2抑制剂治疗前、治疗第4周和治疗8周后AS患者血清中IL-6、IL-17、IL-21、IL-23、TNF-α、TGF-β1的表达情况,检测对照组(20例单独应用COX-2抑制剂的AS患者)治疗前、治疗后的细胞因子水平。结果:肿瘤坏死因子拮抗剂组患者血清中IL-6、IL-17、IL-23、TNF-α的表达在治疗第4周和治疗8周后较本组治疗前及对照组均有明显下降(P0.05);细胞因子IL-21、TGF-β1的表达水平较本组治疗前及对照组无明显降低(P0.05);对照组患者血清中IL-6、IL-17、IL-21、IL-23、TNF-α、TGF-β1的表达在治疗后较治疗前均无明显下降(P0.05);治疗组应用肿瘤坏死因子拮抗剂后较治疗前晨僵及腰背痛VAS评分、BASFI、血沉均显著改善(P0.05),临床疗效优良率为88.0%,对照组优良率为50.0%,有显著差异(P0.05),且治疗组不良反应轻微。结论:肿瘤坏死因子拮抗剂可能是通过降低AS患者血清中一系列细胞因子的表达水平,改善患者的免疫功能及临床症状,延缓了病程进展。但由于病例较少,肿瘤坏死因子拮抗剂联合COX-2抑制剂治疗AS患者的疗效需要在临床中进一步观察。     

Activation of blood coagulation factor VIIa with cleaved tissue factor extracellular domain and crystallization of the active complex

Exposure of blood to tissue factor leads to the formation of a high affinity tissue factor/factor VIIa complex which initiates blood coagulation. As a first step toward obtaining structural information of this enzyme system, a complex of active-site inhibited factor VIIa (F.VIIai) and soluble tissue factor (sTF) was prepared for crystallization. Crystals were obtained, but only after long incubation times. Analysis by SDS-PAGE and mass spectrometry indicated the presence of sTF fragments similar to those formed by proteolytic digestion with subtilisin (Konigsberg, W., Nemerson, Y., Fang, C., Lin, T.-C. Thromb. Haemost. 69:1171, 1993). To test the hypothesis that limited proteolysis of sTF facilitated the crystallization of the complex, sTF fragments were generated by subtilisin digestion and purified. Analysis by tandem mass spectrometry showed the presence of nonoverlapping N- and C-terminal sTF fragments encompassing more than 90% of the tissue factor extracellular domain. Enzymatic assays and binding studies demonstrated that an equimolar mixture of N- and C-terminal fragments bound to factor VIIa and fully restored cofactor activity. A complex of F.VIIai and sTF fragments was prepared for crystallization. Crystals were obtained using microseeding techniques. The best crystals had maximum dimensions of 0.12 × 0.12 × 0.6 mm and showed diffraction to a resolution of 3 Å. © 1995 Wiley-Liss, Inc.     

肠易激综合症患者结肠组织中促肾上腺皮质激素释放因子受体表达的研究

目的 检测肠易激综合症（IBS）患者结肠组织中促肾上腺皮质激素释放因子受体（CRFR）1及CRFR2的表达,探讨其与IBS发病的关系,从而为靶向治疗IBS提供依据.方法 分别采集15例腹泻型IBS（D-IBS）患者、15例便秘型IBS（C-IBS）患者和10例正常健康人结肠组织标本,采用Elivision（TM）PLUS/HRP免疫组化染色方法和Western blot测定CRFR1、CRFR2在各组结肠组织中的蛋白表达.结果 实验结果显示,正常对照组CRFR1和CRFR2免疫组化染色以浅黄色为主,分布范围局限,平均光密度值分别为（0.254±0.099）和（0.201±0.030）;D-IBS组中CRFR1以深或棕黄色为主,分布范围较为广泛,平均光密度值为（0.384±0.048）,显著高于C-IBS组（0.144±0.077）及正常对照组（P〈0.01）;C-IBS组中CRFR2染色以深或棕黄色为主,分布范围较为广泛,平均光密度值为（0.322±0.022）,显著高于D-IBS组（0.162±0.023）（P〈0.01）及正常对照组（P〈0.05）.Western blot结果显示,D-IBS组CRFR1蛋白表达明显高于C-IBS组和正常对照组;C-IBS组CRFR2表达高于D-IBS组和正常对照组.结论 不同亚型IBS患者其CRFR表达的亚型亦不同,提示不同亚型IBS的发生可能与患者结肠组织中CRFR1、CRFR2的表达水平有关.     

调控巨噬细胞迁移抑制因子基因表达的影响因素

巨噬细胞迁移抑制因子(macrophage migration inhibitory factor, MIF)是一种广泛表达的多效性细胞因子,参与多种炎症和免疫疾病的过程并在其中发挥重要作用,是许多疾病的生物标志物或治疗靶点。MIF基因在系统发育中高度保守,在其启动子区有多种不同转录因子的特定结合位点,借此调节MIF的表达。MIF在细胞内外均发挥作用,且MIF是组成型表达。因此,研究调控MIF基因表达和刺激MIF分泌的相关因素具有重要意义。本文通过对MIF基因和MIF启动子上的结合位点的简述,对影响MIF基因表达的相关因素进行总结和归类。根据与MIF基因结合的方式,可分为：(1)与MIF基因启动子特定位点结合,改变转录活性;(2)与MIF CATT5-8微卫星重复序列结合,改变高表达MIF等位基因;(3)非编码RNA调控MIF表达;(4)影响MIF分泌的相关因素。通过对这4类调控MIF基因表达的相关因素的综述,进而认识MIF基因表达的调控机制和影响因素,以期对其治疗相关疾病提供理论基础。     

Zymogenic and enzymatic properties of the 70-80 loop mutants of factor X/Xa

The Ca(2+) binding 70-80 loop of factor X (fX) contains one basic (Arg(71)) and three acidic (Glu(74), Glu(76), and Glu(77)) residues whose contributions to the zymogenic and enzymatic properties of the protein have not been evaluated. We prepared four Ala substitution mutants of fX (R71A, E74A, E76A, and E77A) and characterized their activation kinetics by the factor VIIa and factor IXa in both the absence and presence of cofactors. Factor VIIa exhibited normal activity toward E74A and E76A and less than a twofold impaired activity toward R71A and E77A in both the absence and presence of tissue factor. Similarly, factor IXa in the absence of factor VIIIa exhibited normal activity toward both E74A and E76A; however, its activity toward R71A and E77A was impaired approximately two- to threefold. In the presence of factor VIIIa, factor IX activated all mutants with approximately two- to fivefold impaired catalytic efficiency. In contrast to changes in their zymogenic properties, all mutant enzymes exhibited normal affinities for factor Va, and catalyzed the conversion of prothrombin to thrombin with normal catalytic efficiencies. However, further studies revealed that the affinity of mutant enzymes for interaction with metal ions Na(+) and Ca(2+) was impaired. These results suggest that although charged residues of the 70-80 loop play an insignificant role in fX recognition by the factor VIIa-tissue factor complex, they are critical for the substrate recognition by factor IXa in the intrinsic Xase complex. The results further suggest that mutant residues do not play a specific role in the catalytic function of fXa in the prothrombinase complex.     

临床常规生化检验结果的影响因素分析

目的:探讨临床常规生化检验结果的影响因素,并提出相应的预防对策。方法:回顾性分析2012年2月~2013年2月我院检验科进行的生化常规检测10256例次的检查结果,采用美国BIORAD公司生化定值多项3水平质控品于检测前、中、后进行质控分析,对产生偏差的原因按实验前、实验中、实验后进行归类总结。结果:84例经复核出现超过10%以上偏差,占总分析例数的0.82%。实验前不良事件是产生实验结果偏差的主要因素,占总体产生偏差例数的78.57%,其中患者因素与标本处理不当构成了实验前干扰因素的主体,分别占实验前因素的39.39%和36.36%。不明原因溶血与标本采集方法不当也是实验前的实验干扰因素。实验中影响检测结果的因素主要为仪器故障、试剂过期和失效、定标品或定标曲线过期,分别占实验中因素的46.67%、33.33%、20%。实验后干扰因素均为审核不及时或不细致导致的检测报告不合格。结论:在进行临床常规生化检查的过程中,任何一个环节出现失误均有可能对检查结果造成影响,特别是患者因素、标本采集方法不当及处理不当,均应该引起医护人员的重视。     

Luteotrophic effect of ovulation-inducing factor/nerve growth factor present in the seminal plasma of llamas

The hypothesis that ovulation-inducing factor/nerve growth factor (OIF/NGF) isolated from llama seminal plasma exerts a luteotrophic effect was tested by examining changes in circulating concentrations of LH and progesterone, and the vascular perfusion of the ovulatory follicle and developing CL. Female llamas with a growing follicle of 8 mm or greater in diameter were assigned randomly to one of three groups (n = 10 llamas per group) and given a single intramuscular dose of PBS (1 mL), GnRH (50 μg), or purified OIF/NGF (1.0 mg). Cineloops of ultrasonographic images of the ovary containing the dominant follicle were recorded in brightness and power Doppler modalities. Llamas were examined every 4 hours from the day of treatment (Day 0) until ovulation, and every other day thereafter to Day 16. Still frames were extracted from cineloops for computer-assisted analysis of the vascular area of the preovulatory follicle from treatment to ovulation and of the growing and regressing phases of subsequent CL development. Blood samples were collected for the measurement of plasma LH and progesterone concentrations. The diameter of the dominant follicle at the time of treatment did not differ among groups (P = 0.48). No ovulations were detected in the PBS group but were detected in all llamas given GnRH or OIF/NGF (0/10, 10/10, and 10/10, respectively; P < 0.0001). No difference was detected between the GnRH and OIF/NGF groups in the interval from treatment to ovulation (32.0 ± 1.9 and 30.4 ± 5.7 hours, respectively; P = 0.41) or in maximum CL diameter (13.1 ± 0.4 and 13.5 ± 0.3 mm, respectively; P = 0.44). The preovulatory follicle of llamas treated with OIF/NGF had a greater vascular area at 4 hours after treatment than that of the GnRH group (P < 0.001). Similarly, the luteal tissue of llamas treated with purified OIF/NGF had a greater vascular area than that of the GnRH group on Day 6 after treatment (P < 0.001). The preovulatory surge in plasma LH concentration began, and peaked 1 to 2 hours later in the OIF/NGF group than in the GnRH group (P < 0.05). Plasma progesterone concentration was higher on Day 6 in the OIF/NGF group than in the GnRH group (P < 0.001). Results support the hypothesis that OIF/NGF exerts a luteotrophic effect by altering the secretion pattern of LH and enhancing tissue vascularization during the periovulatory period and early stages of CL development.     

VEGF受体功能研究进展

血管内皮生长因子受体（VEGFR）调控心血管系统的发育。VEGFR1对于造血祖细胞的招募及单核巨噬细胞的迁移是必需的;VEGFR2、VEGFR3在调控血管及淋巴管内皮细胞的功能时发挥重要作用,而现在很多研究都聚焦于阻断VEGFR信号通路以达到阻断肿瘤血管生长的目的。     

Characterization of the adenosine deaminase-related growth factor (ADGF) gene family in Drosophila

A novel family of growth factors, with sequence similarity to adenosine deaminase, has been identified in various organisms including flesh fly, tsetse fly, sand fly, mollusk and human. The human homologue, CECR1, is a candidate gene for the genetic disorder cat eye syndrome. Here, we describe six members of this growth factor family in Drosophila and two in vertebrates. The six Drosophila genes, named adenosine deaminase-related growth factors (ADGF), are found at three different chromosomal locations, with one singleton, two in an inverted orientation, and three in a tandem arrangement. These genes show distinct patterns of expression as measured by RT-PCR and Northern blots, indicating gene-specific function. The presence of six ADGF genes in the Drosophila genome suggests that gene duplication and divergence has been important for these growth factors in insect development. Phylogenetic analysis of the 14 extant ADGF-like gene products shows there are at least three major groups, two of which are found in Drosophila. The third appears specific to the vertebrate line. Seven gene duplications are inferred among the ADGF-like genes, most of which occurred long before the origin of Drosophila. Our analysis predicts the existence of several other unsampled ADGF-like genes, both within the species examined here, and in other related invertebrates.     

Variant forms of upstream stimulatory factors (USFs) control the promoter activity of hTERT,the human gene encoding the catalytic subunit of telomerase

It is known that Myc regulates the expression of TERT, the telomerase catalytic subunit gene, by binding to E box. Here we show that another E box-binding protein, upstream stimulatory factor (USF), also regulates TERT expression. Specifically, the N-terminally truncated form of USF2 is present in telomerase-negative/resting human lymphocytes, but not in telomerase-positive/phytohemagglutinin-activated lymphocytes. In electrophoretic mobility shift assay, both full-length and truncated USF2s bound to the TERT E box. In a transient expression assay, the truncated USF had a dominant-negative effect on both exogenous full-length USF and endogenous positive regulators for activating TERT expression. These results suggest that the differential abundance of truncated USF2 may regulate telomerase activity during lymphocyte activation.