Integrin ��IIb��3 Activation in Chinese Hamster Ovary Cells and Platelets Increases Clustering Rather than Affinity

Integrin αIIbβ3 affinity regulation by talin binding to the cytoplasmic tail of β3 is a generally accepted model for explaining activation of this integrin in Chinese hamster ovary cells and human platelets. Most of the evidence for this model comes from the use of multivalent ligands. This raises the possibility that the activation being measured is that of increased clustering of the integrin rather than affinity. Using a newly developed assay that probes integrins on the surface of cells with only monovalent ligands prior to fixation, I do not find increases in affinity of αIIbβ3 integrins by talin head fragments in Chinese hamster ovary cells, nor do I observe affinity increases in human platelets stimulated with thrombin. Binding to a multivalent ligand does increase in both of these cases. This assay does report affinity increases induced by either Mn²⁺, a cytoplasmic domain mutant (D723R) in the cytoplasmic domain of β3, or preincubation with a peptide ligand. These results reconcile the previously observed differences between talin effects on integrin activation in Drosophila and vertebrate systems and suggest new models for talin regulation of integrin activity in human platelets.     

Chemically Oversulfated Glycosaminoglycans Are Potent Modulators of Contact System Activation and Different Cell Signaling Pathways

Contaminated heparin was associated with adverse reactions by activating the contact system. Chemically oversulfated/modified glycosaminoglycans (GAGs) consisting of heparan sulfate, dermatan sulfate, and chondroitin sulfate have been identified as heparin contaminants. Current studies demonstrated that each component of oversulfated GAGs was comparable with oversulfated chondroitin sulfate in activating the contact system. By testing a series of unrelated negatively charged compounds, we found that the contact system recognized negative charges rather than specific chemical structures. We further tested how oversulfated GAGs and contaminated heparins affect different cell signaling pathways. Our data showed that chemically oversulfated GAGs and contaminated heparin had higher activity than the parent compounds and authentic heparin, indicative of sulfation-dominant and GAG sequence-dependent activities in BaF cell-based models of fibroblast growth factor/fibroblast growth factor receptor, glial cell line-derived neurotrophic factor/c-Ret, and hepatocyte growth factor/c-Met signaling. In summary, these data indicate that contaminated heparins intended for blood anticoagulation not only activated the contact system but also modified different GAG-dependent cell signaling pathways.     

Distinct proteome features of plasma microparticles

Plasma microparticles (MPs) are spherical cell membrane fragments derived from either apoptotic or activated cells. Characterized by a rich phospholipid moiety and many protein constituents, MPs normally circulate in the blood and contribute to numerous physiological processes. In disease states, MPs derived from the injured organ likely contain valuable markers for determining the site, type, and extent of disease pathology. However, the basic protein characteristics of plasma MPs have yet to be described. In this study, MPs from a pooled plasma sample derived from 16 healthy donors, all of group A blood type, were prepared by ultracentrifugation. Flow cytometry confirmed that a majority of these MPs are smaller than 1 microm. Factor Xa generation assay revealed the presence of tissue factor activity in these MPs, confirming MPs' role in initiating blood coagulation. The MP proteome was analyzed by two-dimensional (2-D) gel electrophoresis performed in triplicate, and compared with a 2-D gel of pooled whole plasma and blood platelets. Overall, plasma MPs displayed distinct protein features and a greater number of protein spots (1021-1055) than that detected in whole plasma (331-370). Protein spots expressed in high abundance in the MP proteome were then excised and submitted for protein identity determination. This process provided protein identification for 169 protein spots and reported their relative protein quantities within the MP proteome. These 169 protein spots represented 83 different proteins and their respective isoforms. Thirty of these proteins have never before been reported in previous proteome analyses of human plasma. These results provide unprecedented information on the MP proteome and create a basis for future studies to understand MP biology and pathophysiology.     

Comparison of surface plasmon resonance and quartz crystal microbalance in the study of whole blood and plasma coagulation

The coagulation of blood plasma and whole blood was studied with a surface plasmon resonance (SPR) based device and a quartz crystal microbalance instrument with energy dissipation detection (QCM-D). The SPR and QCM-D response signals were similar in shape but differing in time scales, reflecting differences in detection mechanisms. The QCM-D response time was longer than SPR, as a physical coupling of the sample to the substrate is required for molecules to be detected by the QCM-method. Change of sample properties within the evanescent field is sufficient for detection with SPR. Both the SPR signals and the QCM-D frequency and dissipation shifts showed dependency on concentrations of coagulation activator and sensitivity to heparin additions. The ratio of dissipation to frequency shifts, commonly considered to reflect viscoelastic properties of the sample, varied with the concentration of activator in blood plasma but not in whole blood. Additions of heparin to the thromboplastin activated whole blood sample, however, made the ratio variation reoccur. Implications of these observations for the understanding of the blood coagulation processes as well as the potential of the two methods in the clinic and in research are discussed.     

血栓弹力图的新数学模型及其应用

血栓弹力是动态凝血过程中切应力大小随时间变化的,也是复旨性模量在小的直接反映。提出了一个新的三参数的数学模型表达血栓弹力图,研究了模型参数变化对模型曲线的影响及模型参数与血栓弹力图章是的对应关系,给出了模型参数确切的生理、病理意义。对西苑区院大量血栓弹力图的拟合表明,该模型能比较精确地表达正常及各种病理条件下不正常血栓弹力图的完整变化曲线,而且参数少,拟合出的参数值相当确定,提供了明确直观的凝血机     

织带厂废水处理工艺优化及工程应用研究

优化了水解酸化-接触氧化-混凝处理工艺中的停留时间、混凝剂种类和用量,并将优化后的工艺参数在某织带废水处理工程中进行了应用。结果表明,以硫酸亚铁作为絮凝剂,该织带厂废水经过20h处理后效果良好;其中,pH下降了2.9,CODcr及BOD₅去处效率均达到90%以上,色度去除率达85%;可以确保该织带厂污水处理后达到《广东省水污染物排放限值》(DB44/26-2001)中的第二时段一级标准。该试验为解决广东省织带厂废水处理提供了一条可行途径,并对该类型高浓度染料废水的治理具有借鉴和参考价值。     

围术期影响凝血功能的因素

下肢深静脉血栓形成和肺栓塞已成为临床上不容忽视的问题,如不积极采取预防措施,易使患者术后死亡率升高,因此,围术期进行有效的干预有着重要的临床意义,也受到人们的广泛关注,目前,有很多因素会导致患者术后血液处于高凝状态,现就导致围术期凝血功能发生变化的一些因素作一简单综述,从而引起广大医护人员对术后血液高凝状态的重视,提前做到预防,指导临床工作。     

Factor XII deficiency in asymptomatic Saudi population: A retrospective cohort study

Factor XII (FXII) deficiency is a rare genetic blood disorder. It can lead to a higher risk of developing deep vein thrombosis or acquired thrombotic disorders than the general population. This retrospective study evaluated patients who opted for surgery and were found to have abnormal clotting profiles and clotting factors on preoperative routine blood. Patients were included regardless of whether they were symptomatic or asymptomatic. The cohort comprised 115 patients with a mean FXII level of 128.04 ± 36.93%. Two (1.79%) patients, both of whom were women, had FXII levels <60%. The mean FXII level was 58 ± 1.41 (range, 57–59%) in this group. The present study shows the prevalence of FXII in the asymptomatic Saudi population. The results provide the normal range for FXII. The findings of our study provide the basis for diagnosing F XII deficiency in the asymptomatic Saudi population.     

脓毒症患者血清降钙素原、C-反应蛋白与凝血功能、病情评分的关系及预后的影响因素分析

摘要 目的：探讨脓毒症患者血清降钙素原（PCT）、C-反应蛋白（CRP）与凝血功能、病情评分的关系及预后的影响因素。方法：选择2017年8月至2019年10月我院诊治的150例脓毒症患者作为研究对象,根据脓毒症组患者的生存状况将其分为存活组（n=118）和死亡组（n=32）。检测两组患者血清PCT、CRP水平,凝血酶原时间（PT）和部分凝血活酶时间（APTT）。采用急性生理功能和慢性健康状况评分系统Ⅱ(APACHEⅡ)和序贯器官衰竭估计(SOFA)对两组患者病情进行评估。比较两组患者临床资料。相关性分析采用Pearson检验。患者预后的影响因素采用多因素Logistic回归分析。结果：与存活组相比,死亡组血清PCT、CRP,PT、APTT,APACHE II和SOFA评分均明显升高（P<0.05）。血清PCT>7.32 ng/mL、CRP>86.73 ng/mL、PT>15.48s、APTT>36.74s、APACHE Ⅱ评分>15.88分和SOFA评分>6.48分均是脓毒症患者死亡的危险因素（OR=2.099、1.747、2.333、1.596、1.916、2.208,P<0.05）。血清PCT和CRP均与APACHE Ⅱ评分、SOFA评分、PT和APTT呈正相关（P<0.05）。结论：血清PCT和CRP水平升高与脓毒症患者死亡相关,两者与脓毒症患者APACHE Ⅱ评分、SOFA评分、PT和APTT存在正相关,并且是患者不良预后的影响因素,在脓毒症患者预后的评估中具有一定临床价值。     

胸腔镜辅助小切口与传统开胸手术对胸外伤患者凝血功能及预后的影响

目的:探讨胸腔镜辅助小切口(VTAMS)与传统开胸手术对胸外伤患者凝血功能及预后的影响。方法:回顾性选取2017年7月~2019年2月期间我院收治的胸外伤患者91例,根据手术方式的不同分为A组(n=44,行传统开胸手术)和B组(n=47,行VTAMS手术),比较两组患者围术期指标、术前及术后7d的凝血功能指标、术后并发症发生情况及病死率。结果:B组术中出血量、术中输血量少于A组,手术时间、住院时间短于A组(P<0.05)。两组患者术后7d活化部分凝血酶原时间(APTT)、血小板(PLT)较术前降低,D-二聚体(DD)、凝血酶原时间(PT)较术前升高(P<0.05);B组术后7d的APTT、PLT高于A组,DD、PT则低于A组(P<0.05)。B组术后并发症发生率为10.64%(5/47),低于A组的27.27%(12/44)(P<0.05)。B组病死率为2.13%(1/47),低于A组的15.91%(7/44)(P<0.05)。结论:与传统开胸手术相比,胸外伤患者应用VTAMS手术治疗,可改善围术期指标,对凝血功能影响较轻,减少术后并发症的同时还可降低病死率。