Regulation of fibrinolysis by platelet-released plasminogen activator inhibitor 1: light scattering and ultrastructural examination of lysis of a model platelet-fibrin thrombus

We have investigated the role of plasminogen activator inhibitor 1 (PAI- 1) in the regulation of fibrinolysis using a model thrombus composed of thrombin-stimulated platelets, fibrin(ogen), plasminogen, and recombinant tissue-type plasminogen activator. Laser light scattering kinetic measurements showed that clot lysis was significantly delayed both by thrombin-stimulated platelets and their cell-free releasate. This delay in lysis was almost fully reversed by the addition of a PAI- 1-specific monoclonal antibody that blocks the ability of PAI-1 to inhibit plasminogen activators. Lysis half-times exhibited a linear dependence on the concentration of PAI-1 antigen present, as determined by enzyme-linked immunosorbent assay (ELISA). Sodium dodecylsulfate- polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting confirmed the presence of PAI-1 antigen in the platelet releasates. Scanning electron micrographs of the model thrombus components sampled late in lysis showed considerable unproteolyzed fibrin still attached to platelets. Immunogold cytochemistry detected large amounts of PAI-1 antigen in the partially lysed platelet-fibrin thrombi. This PAI-1 appeared to be bound to the fibrin network rather than to the platelet surface itself. We conclude that the residual clots observed late in lysis represent platelet-associated fibrin to which platelet-released PAI-1 has bound, rendering it less susceptible to degradation.     

European AIDS Clinical Society (EACS) guidelines on the prevention and management of metabolic diseases in HIV

BACKGROUND: Metabolic diseases are frequently observed in HIV-infected persons and, as the risk of contracting these diseases is age-related, their prevalence will increase in the future as a consequence of the benefits of antiretroviral therapy (ART). SUMMARY OF GUIDELINES: All HIV-infected persons should be screened at regular intervals for a history of metabolic disease, dyslipidaemia, diabetes mellitus, hypertension and alteration of body composition; cardiovascular risk and renal function should also be assessed. Efforts to prevent cardiovascular disease will vary in intensity depending on an individual's absolute risk of ischaemic heart disease and should be comprehensive in nature. Lifestyle interventions should focus on counselling to stop smoking, modify diet and take regular exercise. A healthy diet, exercise and maintaining normal body weight tend to reduce dyslipidaemia; if not effective, a change of ART should be considered, followed by use of lipid-lowering medication in high-risk patients. A pre-emptive switch from thymidine analogues is recommended to reduce the risk of development or progression of lipoatrophy. Intra-abdominal fat accumulation is best managed by exercise and diet. Prevention and management of type 2 diabetes mellitus and hypertension follow guidelines used in the general population. When using medical interventions to prevent and/or treat metabolic disease(s), impairment of the efficacy of ART should be avoided by considering the possibility of pharmacokinetic interactions and compromised adherence. Specialists in HIV and specialists in metabolic diseases should consult each other, in particular in difficult-to-treat cases. CONCLUSION: Multiple and relatively simple approaches exist to prevent metabolic diseases in HIV-infected persons; priority should be given to patients at high risk of contracting these diseases.     

Body fluid derived exosomes as a novel template for clinical diagnostics

Background

GH and IGFs serum levels decline with age. Age-related changes appear to be associated to decreases in these anabolic hormones. We have previously demonstrated that IGF-I replacement therapy improves insulin resistance, lipid metabolism and reduces oxidative damage (in brain and liver) in aging rats. Using the same experimental model, the aim of this work was to study whether the exogenous administration of IGF-II, at low doses, acts analogous to IGF-I in aging rats.

Methods

Three experimental groups were included in this study: young healthy controls (yCO, 17 weeks old); untreated old rats (O, 103 weeks old); and aging rats treated with IGF-II (O+IGF-II, 2 μg * 100 g body weight^-1 * day^-1) for 30 days. Analytical parameters were determined in serum by routine laboratory methods using an autoanalyzer (Cobas Mira; Roche Diagnostic System, Basel, Switzerland). Serum levels of hormones (testosterone, IGF-I and insulin) were assessed by RIA. Serum Total Antioxidant Status was evaluated using a colorimetric assay. Mitochondrial membrane potential was evaluated using rhodamine 123 dye (adding different substrates to determine the different states). ATP synthesis in isolated mitochondria was determined by an enzymatic method.

Results

Compared with young controls, untreated old rats showed a reduction of IGF-I and testosterone levels with a decrease of serum total antioxidant status (TAS). IGF-II therapy improved serum antioxidant capability without modifying testosterone and IGF-I circulating concentrations. In addition, IGF-II treatment reduced oxidative damage in brain and liver, improving antioxidant enzyme activities and mitochondrial function. IGF-II was also able to reduce cholesterol and triglycerides levels increasing free fatty acids concentrations.

Conclusions

We demonstrate that low doses of IGF-II induce hepatoprotective, neuroprotective and metabolic effects, improving mitochondrial function, without affecting testosterone and IGF-I levels.     

Follow-up of newborns treated with extracorporeal membrane oxygenation: a nationwide evaluation at 5 years of age

Introduction  

Extracorporeal membrane oxygenation (ECMO) is a supportive cardiopulmonary bypass technique for babies with acute reversible cardiorespiratory failure. We assessed morbidity in ECMO survivors at the age of five years, when they start primary school and major decisions for their school careers must be made.     

可吸收性珊瑚羟基磷灰石与人骨髓间充质干细胞诱导成骨细胞复合培养及碱性成纤维细胞生长因子的作用

目的:观察人骨髓间充质干细胞诱导的成骨细胞与珊瑚羟基磷灰石的相容性及碱性成纤维细胞生长因子的作用。方法:实验于2003-02/2005-10在大连医科大学附属第一医院中心实验室及上海第二医科大学完成。实验材料:①可吸收性珊瑚羟基磷灰石。②人骨髓间充质干细胞:取自单纯性骨囊肿行自体骨髓注射治疗的患者(年龄10～16岁,平均14.5岁),患者均知情同意。实验分组:使用含地塞米松、β甘油磷酸钠和抗坏血酸的条件培养基诱导骨髓间充质干细胞分化为成骨细胞,与珊瑚羟基磷灰石复合培养,分为实验组(RPMI1640完全培养液 成骨细胞 可吸收性珊瑚羟基磷灰石),促增殖组(完全培养液 成骨细胞 可吸收性珊瑚羟基磷灰石 10μg/L碱性成纤维细胞生长因子),正常培养组(完全培养液 同等数量的成骨细胞)。实验评估:①采用扫描电镜观察成骨细胞与可吸收性珊瑚羟基磷灰石复合培养6h,1,3,7d时细胞形态。②成骨细胞附着于材料表面后生长增殖特性:于接种后24h,各组均取6孔细胞用胰蛋白酶消化贴壁细胞,包括材料上贴附的细胞,计数孔内细胞数及平均细胞数,绘制细胞生长曲线。③成骨细胞分泌碱性磷酸酶活性的测定:于接种后1,3,5,7d采用酶联免疫监测仪测410nm波长的吸光度值,计算每1000个细胞的吸光度值。结果:①成骨细胞与可吸收性珊瑚羟基磷灰石复合培养后细胞形态:复合培养6h,细胞多为单层结构,形态多样,有数个突起;复合培养1d,成骨细胞附着于可吸收性珊瑚羟基磷灰石表面并深入到材料的孔隙内,与材料牢固结合,并在材料表面伸展,细胞表面可见大量微绒毛;复合培养7d,细胞数量增多,可见少量胞体表面及细胞间有颗粒状钙盐结晶沉积,细胞形态无明显差异。②成骨细胞附着于材料表面后生长增殖特性:实验组细胞接种后,随时间延长数量逐渐增加,仍可保持正常的分裂增殖速度,与正常培养组相比差异无显著性意义(P>0.05)。复合培养4,5,6,7d后促增殖组细胞附着载体后数量增长明显高于实验组、正常培养组,差异均有显著性意义(P<0.05)。③成骨细胞分泌碱性磷酸酶活性的测定:随着培养时间的增加,3组细胞碱性磷酸酶含量(每1000个细胞的平均吸光度值)均逐渐增高(以实验组为例,复合培养1,3,5,7d分别为0.0121±0.0014,0.0154±0.0013,0.0172±0.0012,0.0183±0.0015),差异无显著性意义(P>0.05)。结论:①人骨髓间充质干细胞诱导的成骨细胞可以在一定的生物载体上正常生长、增殖,并保持生理功能。②10μg/L碱性成纤维细胞生长因子可促进此过程中细胞增殖。     

Deep white matter infarction: correlation of MR imaging and histopathologic findings

Focal and confluent areas of periventricular hyperintensity have been reported on magnetic resonance (MR) images in 30% of patients over 60 years of age. In order to better understand the pathologic basis of these lesions, the authors studied 14 formalin-fixed brains with MR imaging. Multiple focal areas of hyperintensity were identified in the periventricular white matter in three of the 14 brains studied (21%). Subsequent gross and microscopic pathologic examination of both hyperintense and normal-intensity areas was performed on 87 tissue sections. The larger lesions were characterized centrally by necrosis, axonal loss, and demyelination and therefore represent true infarcts. Reactive astrocytes oriented along the degenerated axons were identified at distances of up to several centimeters from the central infarct. This is called isomorphic gliosis and is associated with increased intensity on T2-weighted images that increases the apparent size of the central lesion.