蝎蜂毒肽对大鼠纤溶系统作用初探

本研究采用大鼠肢体血管灌流和整体给药两种模型，观察蝎蜂毒（ＳＢＰ）对血管理灌流液内纤溶酶原激活物（ＰＡ）活性、血浆优球蛋白纤溶性（ＥＦＡ）和纤溶酶（ＰＬ）活性的影响。结果说明，ＳＢＰ有明显激活纤溶系统作用；其机制可能涉及血管内皮细胞释放ＰＡ活性增加，进一步促使纤溶酶原活化为ＰＬ增多的途径。     

Stromal cell-derived factor-1/CXCR4 signaling modifies the capillary-like organization of human embryonic stem cell-derived endothelium in vitro.

The molecular mechanisms that regulate human blood vessel formation during early development are largely unknown. Here we used human ESCs (hESCs) as an in vitro model to explore early human vasculogenesis. We demonstrated that stromal cell-derived factor-1 (SDF-1) and CXCR4 were expressed concurrently with hESC-derived embryonic endothelial differentiation. Human ESC-derived embryonic endothelial cells underwent dose-dependent chemotaxis to SDF-1, which enhanced vascular network formation in Matrigel. Blocking of CXCR4 signaling abolished capillary-like structures induced by SDF-1. Inhibition of the SDF-1/CXCR4 signaling pathway by AMD3100, a CXCR4 antagonist, disrupted the endothelial sprouting outgrowth from human embryoid bodies, suggesting that the SDF-1/CXCR4 axis plays a critical role in regulating initial vessel formation, and may function as a morphogen during human embryonic vascular development.     

下胫腓联合分离内固定术式的生物力学研究

目的　探讨下胫腓联合分离采用新型内固定术式———下胫腓钩板固定器 (Hook -platefixation ,HPF)的生物力学特性 ,与螺钉、钢板和带钩固定器三种内固定方式比较 ,为临床提供科学依据。方法　采用新鲜成人尸体足标本 6具 ,运用生物力学实验应力分析方法和压敏片技术 ,测量不同内固定术式的远端胫腓骨强度、应变、负重面积、接触应力和足弓承载能力及踝关节稳定性的变化。结果　新型下胫腓钩板固定器内固定术式无论在胫腓骨强度和刚度、负重面积、接触压力、足弓的变形、移位强度和刚度、承载能力以及踝关节的稳定性方面均优于其它三种内固定术式 ,具有显著性差异 (P <0 .0 1)。结论　实验结果表明 ,采用下胫腓钩板固定器 (HPF) ,既有利于提高生物力学性能 ,又有利于改善踝关节的稳定性 ,与传统手术方式相比可减少一次手术 ,避免了断钉等并发症 ,且能有效地提高足部承载能力 ,是下胫腓联合分离内固定的一种优良术式     

不同转移特性瘤细胞系的筛选及其生物学特性

目的：探讨与肿瘤转移相关的某些生物学特性。方法：将小鼠乳腺癌Ｃａ７６１－ＦＰ８／Ｌ和Ｃａ７６１－ＦＬ１０／Ｌ经体内筛选得到细胞系Ｃａ７６１－Ｐ５Ｂ和Ｃａ７６１＝Ｌ６Ｂ，并观察其瘤细胞与凝集反应、靶器官组织条件培养基对瘤细胞真挚化作用等，结果：Ｃａ７６１－Ｐ５Ｂ具有高肺转移、低淋巴结转移特性，Ｃａ７６１－Ｌ５Ｂ具有低肺、低淋巴结转移特性。两个瘤细胞系的细胞表面的糖基表达，对条件培养的趋化反应不同。结     

Thioredoxin suppresses 1-methyl-4-phenylpyridinium-induced neurotoxicity in rat PC12 cells

Thioredoxin (TRX) is a redox-active protein which plays a cytoprotective role against oxidative stress. Geranylgeranylacetone (GGA), used widely as an anti-ulcer drug, has been reported to induce TRX as well as heat shock protein 70 (HSP70) in hepatocytes and other cells. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), causes dopaminergic denervation and Parkinsonism in humans. The 1-methyl-4-phenylpyridinium ion (MPP(+)), an active metabolite of MPTP, induces cell death in a rat pheochromocytoma cell line (PC12 cells). We found that MPP(+) suppresses TRX expression in PC12 cells. Overexpression or administration of TRX attenuates MPP(+)-induced neurotoxicity on PC12 cells. Moreover, GGA induces expression of TRX and HSP70 and attenuates MPP(+)-induced toxicity in PC12 cells. These results indicate that TRX and GGA have a possible potential as new therapeutic agents for Parkinson disease.     

Functional tyrosine kinase inhibitor profiling: a generally applicable method points to a novel role of platelet-derived growth factor receptor-beta in tuberous sclerosis

A ubiquitous herpesvirus that establishes life-long infection, the Epstein-Barr virus (EBV) has yielded little insight into how a single agent in general accord with its host can produce diverse pathologies ranging from oral hairy leukoplakia to nasopharyngeal carcinoma, from infectious mononucleosis to Hodgkin's disease (HD) and Burkitt's lymphoma. Its pathogenesis is further confounded by the less than total association of virus with histologically similar tumors. In other viral systems, defective (interfering) viral genomes are known to modulate outcome of infection, with either ameliorating or intensifying effects on disease processes initiated by prototype strains. To ascertain whether defective EBV genomes are present in HD, we examined paraffin-embedded tissue from 56 HD cases whose EBV status was first determined by cytohybridization for nonpolyadenylated EBV RNAs (EBERs). Using both standard polymerase chain reaction (PCR) and PCR in situ hybridization, we successfully amplified sequences that span abnormally juxtaposed BamHI W and Z fragments characteristic of defective heterogeneous (het) EBV DNA from 10 of 32 (31%) EBER-positive tumors. Of 24 EBER-negative HD, 8 yielded PCR products indicating presence of het EBV DNA. Two of these contained defective EBV in the apparent absence of the prototype virus. Of the 42 tumors analyzed for defective EBV by both PCR techniques, there was concordance of results in 38 (90%). Detection of defective EBV genomes with the potential to disrupt viral gene regulation suggests one mechanism for pathogenic diversity that may also account for loss of prototypic EBV from individual tumor cells.     

A slice-by-slice blurring model and kernel evaluation using the Klein-Nishina formula for 3D scatter compensation in parallel and converging beam SPECT

Converging collimation increases the geometric efficiency for imaging small organs, such as the heart, but also increases the difficulty of correcting for the physical effects of attenuation, geometric response and scatter in SPECT. In this paper, 3D first-order Compton scatter in non-uniform scattering media is modelled by using an efficient slice by-slice incremental blurring technique in both parallel and converging beam SPECT. The scatter projections are generated by first forming an effective scatter source image (ESSI), then forward-projecting the ESSI. The Compton scatter cross section described by the Klein-Nishina formula is used to obtain spatial scatter response functions (SSRFs) of scattering slices which are parallel to the detector surface. Two SSRFs of neighbouring scattering slices are used to compute two small orthogonal 1D blurring kernels used for the incremental blurring from the slice which is further from the detector surface to the slice which is closer to the detector surface. First-order Compton scatter point response functions (SPRFs) obtained using the proposed model agree well with those of Monte Carlo (MC) simulations for both parallel and fan beam SPECT. Image reconstruction in fan beam SPECT MC simulation studies shows increased left ventricle myocardium-to-chamber contrast (LV contrast) and slightly improved image resolution when performing scatter compensation using the proposed model. Physical torso phantom fan beam SPECT experiments show increased myocardial uniformity and image resolution as well as increased LV contrast. The proposed method efficiently models the 3D first-order Compton scatter effect in parallel and converging beam SPECT.     

脑缺血再灌流对大鼠海马FOS蛋白的诱导及电针对其的影响

目的　探讨脑缺血再灌流后电针对大鼠海马FOS蛋白表达的影响。方法　采用夹闭大鼠双侧颈总动脉造成的脑缺血再灌流损伤模型 ,电针“百会”、“风池”、“大钟”及“足三里”穴 ,频率 2～ 2 0Hz,强度以肌肉轻微抖动为准 ,持续 30min ,4h后观察海马FOS蛋白的表达。结果　电针能明显加强脑缺血再灌流后海马各区FOS蛋白的表达。结论　缺血再灌流可诱导海马FOS蛋白的显著表达 ;电针信息对缺血后海马神经元的功能可能会有影响。     

用SYBR-Green Ⅰ实时荧光PCR结合融解曲线分析法诊断α-地中海贫血

目的建立自动化、高通量、准确快速检测缺失型α-地中海贫血基因型的技术。方法应用SYBR-Green1进行两个实时荧光聚合酶链反应(real-time fluorescence polymerase chain reaction with SYBR-Green1,SYBR-PCR),检测左缺(-α4.2)、右缺(-α3.7)等位基因,同时进行融解曲线(dissociation curve,DC)和Tm(melting temperature)值分析。PCR产物重组到pCR2.1,重组子梯度稀释作为模板检测灵敏度,确定两种等位基因型(-α4.2,-α3.7)的检测下限,并对110份DNA样品进行检测。结果检测-α4.2和-α3.7的PCR产物长度分别为1.65kb、1.9kb,Tm分别为(81.5±0.5)℃、(82.5±0.5)℃,检测下限分别为9×102个拷贝、4.3×102个拷贝。该检测技术的灵敏度较常规PCR结合琼脂糖凝胶电泳法高10倍。结论SYBR-Green1实时荧光PCR结合融解曲线分析及Tm分析可以灵敏、准确地检测-α4.2、-α3.7、αα(包括αTα)及--SEA4种等位基因,从而为各种缺失型α-地中海贫血做出基因诊断。该技术具有自动化程度高,不需荧光标记探针,成本低,易质控,防污染,高通量等优点,适于临床推广应用。     

Differentiation of mycobacterial species by PCR-restriction analysis of DNA (342 base pairs) of the RNA polymerase gene (rpoB)

PCR amplification-restriction analysis (PRA) of rpoB DNA (342 bp), which comprises the Rif(r) region, was used for the differential identification of 49 mycobacteria. The DNA had been used previously for the identification of mycobacterial species by comparative sequence analysis (B. J. Kim et al., J. Clin. Microbiol. 37:1714-1720, 1999). Digestion with four restriction enzymes (HaeIII, HindII, MvaI, and AccII), which were selected on the basis of rpoB DNA sequences, generated distinctive PRA patterns that allowed not only the reference strains but also the clinical isolates of mycobacteria to be distinguished. Both rapidly and slowly growing mycobacteria were distinctly differentiated by HaeIII digestion of the amplified rpoB DNA. By HindII digestion the Mycobacterium tuberculosis complex was distinguished from the other mycobacteria. Furthermore, six subspecies of Mycobacterium kansasii (subspecies I to VI) as well as the closely related Mycobacterium gastri, and other closely related species, were distinguished by simultaneous digestion of MvaI and AccII. According to the rpoB PRA scheme, 240 strains of clinical isolates could be identified. It was also possible to detect and identify M. tuberculosis directly from sputa and bronchoalveolar lavage specimens. These results suggest that PRA of rpoB DNA is a simple and feasible method not only for the differentiation of culture isolates but also for the rapid detection and identification of pathogenic mycobacteria in primary clinical specimens.