Endoscopy-Related Bleeding and Thromboembolic Events in Patients on Direct Oral Anticoagulants or Vitamin K Antagonists

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Anticoagulation Strategies in Patients With Cancer: JACC Review Topic of the Week

Patients with active cancer are at an increased risk of arterial and venous thromboembolism (VTE) and bleeding events. Historically, in patients with cancer, low molecular weight heparins have been preferred for treatment of VTE, whereas warfarin has been the standard anticoagulant for stroke prevention in patients with atrial fibrillation (AF). More recently, direct oral anticoagulants (DOACs) have been demonstrated to reduce the risk of venous and arterial thromboembolism in large randomized clinical trials of patients with VTE and AF, respectively, thus providing an attractive oral dosing option that does not require routine laboratory monitoring. In this review, we summarize available clinical trial data and guideline recommendations, and outline a practical approach to anticoagulation management of VTE and AF in cancer.     

液相色谱-电喷雾串联质谱分析人全血中环孢素的基质效应评估及其机理探究

目的： 评估液相色谱-电喷雾串联质谱（LC-ESI-MS/MS）分析人全血中环孢素的基质效应，并探究其发生机理。方法： 全血裂解物的蛋白沉淀上清液用作全血基质。分别用乙腈水溶液和全血基质配制等浓度环孢素A（CyA）、环孢素C（CyC）的质控样品。分别在添加H⁺、NH₄⁺和Na⁺的流动相中，用LC-ESI-MS/MS的MRM模式检测质控样品中CyA，CyC的[M+H]⁺、[M+NH₄]⁺和[M+Na]⁺（M=CyA，CyC）峰面积，以其计算基质效应因子；用MS Scan模式检查质控样品中CyA、CyC色谱流出峰的质谱离子组成情况，用于判断基质效应原因。结果： 在添加H⁺、NH₄⁺和Na⁺的流动相中，全血基质中CyA、CyC基质效应因子分别为-76.6%~-54.0%、-86.0%~-55.3%和-42.8%~-34.1%。在加H⁺、加NH₄⁺流动相中，标准液加全血基质的CyA、CyC色谱峰的质谱中出现丰度很高的[M+Na]⁺和[M+K]⁺，在加Na⁺流动相中它们出现丰度很高的[M+K]⁺，而对应的定量离子[M+H]⁺、[M+NH₄]⁺或[M+Na]⁺的丰度显著降低。结论： 全血基质对环孢素的LC-ESI-MS/MS分析产生明显的基质效应，其原因与基质中Na⁺、K⁺同添加在流动相中用于辅助电离的H⁺、NH₄⁺或Na⁺竞争与环孢素加合，导致定量目标加合离子丰度显著降低有关。     

溴敌隆的家栖鼠实验室适口性和现场灭鼠效果评价

目的　评价溴敌隆防制家栖鼠的效果。方法　实验室有选择适口性试验 ,现场灭家栖鼠效果考核。结果　在有选择的摄食试验条件下 ,0 .0 0 5 %溴敌隆大米毒饵对褐家鼠和黄胸鼠的毒杀率达 10 0 %和 94 .4 4 % ,摄食系数分别为 0 .6 3和 0 .5 4 ,致死剂量分别为 9.97(0 .0 6～ 2 4 .6 9)和 7.93(5～ 17.6 1)mg/kg。现场灭家栖鼠试验 ,灭鼠率达 86 .4 3%。结论　溴敌隆对家栖鼠毒效髙 ,适口性好 ,具有较好的防制效果     

β2-glycoprotein I, anti-β2-glycoprotein I, and fibrinolysis

β₂-glycoprotein-I (β₂GPI) is a phospholipid-binding plasma protein that consists of five homologous domains. Domain V is distinguished from others by bearing a positively charged lysine cluster and hydrophobic extra C-terminal loop. β₂GPI has been known as a natural anticoagulant regulator. β₂GPI exerts anticoagulant activity by inhibition of phospholipid-dependent coagulation reactions such as prothrombinase, tenase, and factor XII activation. It also binds factor XI and inhibits its activation. On the other hand, β₂GPI inhibits anticoagulant activity of activated protein C. According to the data from knockout mice, β₂GPI may contribute to thrombin generation in vivo. Phospholipid-bound β₂GPI is one of the major target antigens for antiphospholipid antibodies present in patients with antiphospholipid syndrome (APS). Binding of pathogenic anti-β₂GPI antibodies increases the affinity of β₂GPI to the cell surface and disrupts the coagulation/fibrinolysis balance on the cell surface. These pathogenic antibodies activate endothelial cells via signal transduction events in the presence of β₂GPI. Impaired fibrinolysis has been reported in patients with APS. Using a newly developed chromogenic assay, we demonstrated lower activity of intrinsic fibrinolysis in euglobulin fractions from APS patients. Addition of monoclonal anti-β₂GPI antibodies with β₂GPI also decreased fibrinolytic activity in this assay system. β₂GPI is proteolytically cleaved by plasmin in domain V (nicked β₂GPI) and becomes unable to bind to phospholipids, reducing antigenicity against antiphospholipid antibodies. This cleavage occurs in patients with increased fibrinolysis turnover. Nicked β₂GPI binds to plasminogen and suppresses plasmin generation in the presence of fibrin, plasminogen, and tissue plasminogen activator (tPA). Thus, nicked β₂GPI plays a role in the extrinsic fibrinolysis via a negative feedback pathway loop.     

狼疮抗凝物质45例临床分析

本文报道从1985年7月到1993年12月检出有狼疮抗凝物质患者45例,有血栓栓塞现象14例,占31.11％。我们就其病种、临床表现、实验室检查、治疗及预后进行分析。     

Different clinical presentations of a lupus anticoagulant in the same family

Summary A young man who had suffered several episodes of deep-vein thrombosis of the legs since the age of 20 had a myocardial infarction at the age of 33, at which time both a prolonged partial thromboplastin time (PTT), compatible with a lupus anticoagulant (LA), and decreased fibrinolytic capacity (FC) were found.His sister presented with deep-vein thrombosis of a leg and subsequent pulmonary embolism when she was 18 years old. She had a miscarriage three years later and developed a hemolytic-uremic syndrome at the age of 35. The PT and FC were normal. Laboratory investigations of the parents revealed positive antinuclear antibodies in the mother's serum but no anomaly in the father.This study suggests a familial tendency to develop autoimmune disorders associated with LA and thromboembolic complications related to decreased FC.     

Inhibition of heparin/protamine complex-induced complement activation by Compstatin in baboons

Complement activation products are major components of the inflammatory response induced by cardiac surgery and cardiopulmonary bypass which contribute to postoperative organ dysfunction, fluid accumulation, and morbidity. Activation of the complement system occurs during extracorporeal circulation, during reperfusion of ischemic tissue, and after the formation of heparin-protamine complexes. In this study we examine the efficacy of Compstatin, a recently discovered peptide inhibitor of complement, in preventing heparin/protamine-induced complement activation in baboons. The study was performed in baboons because Compstatin binds to baboon C3 and is resistant to proteolytic cleavage in baboon blood (similar to humans); Compstatin inhibits only the activation of primates' complement system. After testing various doses and administration regimens, Compstatin produced complete inhibition at a total dose of 21 mg/kg when given as a combination of bolus injection and infusion. Compstatin completely inhibited in vivo heparin/protamine-induced complement activation without adverse effects on heart rate or systemic arterial, central venous, and pulmonary arterial pressures. This study indicates that Compstatin is a safe and effective complement inhibitor that has the potential to prevent complement activation during and after clinical cardiac surgery. Furthermore, Compstatin can serve as the prototype for designing an orally administrated drug.