Surrogate markers for cerebral blood flow correlate with [18F]‐fallypride binding potential at dopamine D2/3 receptors in human striatum

Positron emission tomography (PET) with the high affinity dopamine D_2/3 receptor ligand [¹⁸F]‐fallypride affords estimates of the binding potential (BP_ND) in extra‐striatal regions of low receptor abundance, but the sufficient recording time for accurate measurements in striatum has been called into question. We have earlier argued that transient equilibrium measurements are obtained in striatum with [¹⁸F]‐fallypride PET recordings of 3 h duration, which may be the practical limit for clinical investigations without interrupted scanning. However, the high extraction fraction of [¹⁸F]‐fallypride predicts flow‐dependence of tracer delivery to brain, which may be a source of variance of the apparent BP_ND in regions of high binding. To test this prediction, we conducted a retrospective analysis of [¹⁸F]‐fallypride PET data from a group of 50 healthy volunteers (age 18–58 years [mean ± SD: 32.6 ± 10.6), who had participated in clinical studies without arterial input measurements. We used the initial 120‐s integral (AUC) of the venous confluence (VC) as a surrogate marker for cerebral blood flow (CBF) and tested for correlations between regional estimates of BP_ND calculated by the simplified reference tissue model (SRTM) and the individual VC‐AUC. The magnitude of BP_ND in a high binding region (putamen), but not in a low binding region (thalamus) correlated positively with VC‐AUC, suggesting that approximately 9% of the variance in the [¹⁸F]‐fallypride BP_ND in putamen can be attributed to individual differences in this surrogate marker for CBF, a contribution equal in magnitude to the effects of age on BP_ND in putamen of the present healthy control group. Synapse, 2013. © 2012 Wiley Periodicals, Inc.     

亚麻子水提液对DPP-4及α-葡萄糖苷酶活性抑制实验研究

目的通过观察亚麻子水提液对二肽基肽酶-4（DPP-4）、α-葡萄糖苷酶抑制作用,为该药防治糖尿病提供实验依据。方法①以DPP-4酶、缓冲液、底物建立DPP-4抑制剂的体外筛选体系,对亚麻子水提液进行抑制实验,采用发色底物法测定吸光度（OD）,计算DPP-4抑制率及IC50值;②以蔗糖为底物建立α-葡萄糖苷酶活性抑制模型,采用葡萄糖氧化酶法测定亚麻子水提液对α-葡萄糖苷酶的抑制作用,计算其抑制率和IC50值。结果①亚麻子具有轻度DPP-4抑制作用,其IC50值738.20mg/L;②亚麻子具有α-葡萄糖苷酶抑制作用,其IC50值为365.9mg/mL。结论亚麻子水提液可一定程度地抑制DPP-4及α-葡萄糖苷酶活性。     

广州市荔湾区青少年脊柱侧凸患病率的调查研究

目的了解广州市荔湾区青少年脊柱侧凸的患病率。方法 2011年7月~2012年1月对荔湾区8351名7~15岁在校中小学生进行了脊柱侧凸普查,应用脊柱侧凸两检法（体检、X线照片）,体检阳性或可疑阳性者到医院照脊柱全长正侧位X片,采用Cobb法测量,Cobb角≥10°诊断为脊柱侧凸。结果一检阳性结果 175名（2.1%）,二检阳性为85名（1.02%）,男性31名,女性54名,男∶女患病率比为1∶1.76,其中特发性脊柱侧凸81名,占95.3%,先天性侧凸3名,神经肌肉源性1名。结论荔湾区中小学生脊柱侧凸发病率为1.02%,通过普查,可以早发现、早诊断青少年脊柱侧凸,及时选择适当方法进行治疗。     

von Willebrand factor released from Weibel-Palade bodies binds more avidly to extracellular matrix than that secreted constitutively

Large multimers of von Willebrand factor (vWf) are released from the Weibel-Palade bodies of cultured endothelial cells following treatment with a secretagogue (Sporn et al, Cell 46:185, 1986). These multimers were shown by immunofluorescent staining to bind more extensively to the extracellular matrix of human foreskin fibroblasts than constitutively secreted vWf, which is composed predominantly of dimeric molecules. Increased binding of A23187-released vWf was not due to another component present in the releasate, since releasate from which vWf was adsorbed, when added together with constitutively secreted vWf, did not promote binding. When iodinated plasma vWf was overlaid onto the fibroblasts, the large forms bound preferentially to the matrix. These results indicated that the enhanced binding of the vWf released from the Weibel-Palade bodies was likely due to its large multimeric size. It appears that multivalency is an important component of vWf interaction with the extracellular matrix, just as has been shown for vWf interaction with platelets. The pool of vWf contained within the Weibel-Palade bodies, therefore, is not only especially suited for platelet binding, but also for interaction with the extracellular matrix.     

Hematopoietic defects in mice lacking the sialomucin CD34

Although the pluripotent hematopoietic stem cell can only be definitively identified by its ability to reconstitute the various mature blood lineages, a diversity of cell surface antigens have also been specifically recognized on this subset of hematopoietic progenitors. One such stem cell-associated antigen is the sialomucin CD34, a highly O-glycosylated cell surface glycoprotein that has also been shown to be expressed on all vascular endothelial cells throughout murine embryogenesis as well as in the adult. The functional significance of CD34 expression on hematopoietic progenitor cells and developing blood vessels is unknown. To analyze the involvement of CD34 in hematopoiesis, we have produced both embryonic stem (ES) cells and mice that are null for the expression of this mucin. Analysis of yolk saclike hematopoietic development in embryoid bodies derived from CD34- null ES cells showed a significant delay in both erythroid and myeloid differentiation that could be reversed by transfection of the mutant ES cells with CD34 constructs expressing either a complete or truncated cytoplasmic domain. Measurements of colony-forming activity of hematopoietic progenitor cells derived from yolk sacs or fetal livers isolated from CD34-null embryos also showed a decreased number of these precursor cells. In spite of these diminished embryonic hematopoietic progenitor numbers, the CD34-null mice developed normally, and the hematopoietic profile of adult blood appeared typical. However, the colony-forming activity of hematopoietic progenitors derived from both bone marrow and spleen is significantly reduced in adult CD34-deficient animals, and these CD34-deficient progenitors also appear to be unable to expand in liquid cultures in response to hematopoietic growth factors. Even with these apparent progenitor cell deficiencies, CD34- null animals showed kinetics of erythroid, myeloid, and platelet recovery after sublethal irradiation that are indistinguishable from wild-type mice. These data strongly suggest that CD34 plays an important role in the formation of progenitor cells during both embryonic and adult hematopoiesis. However, the hematopoietic sites of adult CD34-deficient mice may still have a significant reservoir of progenitor cells that allows for normal recovery after nonmyeloablative peripheral cell depletion.     

Inactivation of purified human alpha 2-antiplasmin and purified human C1 inhibitor by synthetic fibrinolytic agents

3-Hydroxypropyl flufenamide (Flu-HPA) is one of a series of flufenamic acid derivatives that enhances blood clot lysis in vitro. Studies of possible mechanisms of action of Flu-HPA were undertaken. The profibrinolytic activity of Flu-HPA in clot lysis assays was found to be dependent on plasminogen. The influence of Flu-HPA on the ability of purified alpha 2-antiplasmin to inhibit purified plasmin was studied. Plasmin activity was determined using 125I-fibrin plates or the spectrophotometric tripeptide substrate, Val-Leu-Lys-paranitroanilide. At Flu-HPA concentrations greater than 1 mM, the inhibitory activity of alpha 2-antiplasmin was abolished in a time-dependent and concentration- dependent manner. The influence of Flu-HPA on the ability of purified Cl inhibitor to inhibit purified plasma kallikrein and beta-Factor XIIa was also studied. Cl inhibitor activity was abolished by Flu-HPA at concentrations greater than 2 mM. Notably, Flu-HPA up to 60 mM did not affect the amidolytic activities of plasmin, kallikrein, or beta-Factor XIIa. Flu-HPA did not release enzyme activity from preformed complexes of either alpha 2-antiplasmin and plasmin of Cl inhibitor and kallikrein. A water-soluble derivative of flufenamic acid, N-flufenamyl- glutamic acid, also inactivated alpha 2-antiplasm and Cl inhibitor. This inactivation was shown to be reversible. These results indicate that synthetic fibrinolytic compounds such as flufenamic acid derivatives may promote fibrinolysis by directly inactivating alpha 2- antiplasmin and Cl inhibitor.     

Contrasting effects of recombinant human granulocyte-macrophage colony- stimulating factor (CSF) and granulocyte CSF treatment on the cycling of blood elements in childhood-onset cyclic neutropenia

Recombinant human granulocyte colony-stimulating factor (G-CSF) treatment has been shown to increase average neutrophil counts substantially in patients with childhood-onset cyclic neutropenia (or "cyclic hematopoiesis"), but not to eliminate the cyclic oscillations of neutrophil counts or those of other blood elements (monocytes, platelets, eosinophils, and reticulocytes) that are characteristic of this hematopoietic disorder. Indeed, oscillations of neutrophil counts are amplified during G-CSF treatment. We have compared the effects of recombinant granulocyte-macrophage-CSF (GM-CSF) with those of G-CSF in three patients with this disease (2 men and 1 woman, 17, 30, and 32 years of age). These patients were treated with GM-CSF (2.1 micrograms/kg/day, subcutaneously) for 6 weeks, preceded and followed by 6 to 13 weeks of detailed observation to document changes in the cyclic oscillations of blood neutrophils and other blood elements; two of the patients were subsequently treated with G-CSF (5.0 micrograms/kg/d, subcutaneously) and observed for comparable periods of time. Unlike G-CSF treatment, which increased average neutrophil counts more than 20-fold, GM-CSF increased neutrophil counts only modestly, from 1.6- to 3.9-fold, although eosinophilia of varying prominence was induced in each patient. However, at the same time, GM-CSF treatment dampened or eliminated the multilineage oscillations of circulating blood elements (neutrophils, monocytes, platelets, and/or reticulocytes) in each of the patients. In contrast, G-CSF treatment of the same patients markedly amplified the oscillations of neutrophil counts and caused the cycling of other blood elements (monocytes in particular) to become more distinct. These findings support the conclusion that the distinctive cycling of blood cell production in childhood-onset cyclic neutropenia results from abnormalities in the coordinate regulation of both GM-CSF-responsive, multipotential progenitor cells and G-CSF-responsive, lineage-restricted, neutrophil progenitors.     

基于1H-NMR植物代谢组学技术分析青海产区枸杞子的化学特征

目的:采用核磁共振氢谱(~1H-NMR)植物代谢组学技术比较青海产区枸杞子与其他产区(宁夏、甘肃、新疆、内蒙古)枸杞子的化学成分差异。方法:收集5个产区共97份枸杞子样本,其中青海61个样本,采用50%甲醇提取,检测~1H-NMR图谱,结合多元统计分析,对比青海产区枸杞子与其他产区枸杞子的化学差异性,并对各产区样本的枸杞多糖进行含量测定(以无水葡萄糖计),检测波长490 nm。结果:枸杞子的~1H-NMR图谱共检测到32个化学成分,多元统计分析表明青海产区枸杞子与其他产区样本相比,无明显分离趋势;青海产区枸杞子与宁夏产区相比,以及青海省6个不同地区的枸杞子相比,重叠样品较多,均不能显著分开。相似度结果表明,大多数样品的相似度0.85;化合物的单变量分析结果显示,除了蔗糖、葡萄糖、脯氨酸等个别代谢物在各产区样本中存在显著差异外,其余代谢物在各产区样品中的含量分布基本一致。青海与其他产区样本中枸杞多糖含量无显著性差异,且枸杞多糖含量与~1H-NMR指认的小分子化合物的相关系数处于-0.2～0.4。结论:采用~1HNMR植物代谢组学技术从整体化学组成上分析了青海产区枸杞子的化学特征,并结合枸杞多糖含量测定,显示青海产区枸杞子与其他产区枸杞子的化学差异较小。建立的基于~1H-NMR的枸杞子质量评价方法可为其质控水平提升及种植产区选择提供科学依据。     

外源性p53对Wnt通路抑制因子Dickkopf-1的表达作用

目的研究外源性p53对W nt通路抑制因子D ickkopf-1(DKK-1)的表达作用。方法将携带p53基因的复制缺陷型腺病毒载体(Adp53)导入到p53完全缺失的人肝癌细胞株Hep3B中,并以p53反以寡核苷酸阻断p53阳性细胞p53的表达,以W nt通路的关键因子-βcaten in的改变为功能指标评价W nt通路的变化。以RT-PCR技术检测W nt通路抑制因子DKK-1表达的调节作用,以流式细胞术检测Adp53的转基因情况,肝癌细胞中p53和β-caten in的表达。结果DKK-1mRNA水平在转染Adp53 20 h后即有明显升高,32 h达最高水平,随后逐渐降低。β-caten in表达水平随着转染时间和转染剂量的增加,阳性细胞百分比强度和平均荧光量强度表达水平逐渐下降。以p53反以寡核苷酸阻断p53阳性细胞p53表达后,抑制剂DKK-1的表达逐渐降低,-βcaten in表达水平逐渐增加。结论外源性p53能明显诱导W nt通路抑制剂DKK-1的表达,进而产生抑制W nt通路的作用。