1,720,982 research outputs found
Fibrin as a scaffold for cardiac tissue engineering
No full textFibrin is a natural biopolymer with many interesting properties, such as biocompatibility, bioresorbability, ease of processing, ability to be tailored to modify the conditions of polymerization, and potential for incorporation of both cells and cell mediators. Moreover, the fibrin network has a nanometric fibrous structure, mimicking extracellular matrix, and it can also be used in autologous applications. Therefore, fibrin has found many applications in tissue engineering, combined with cells, growth factors, or drugs. Because a major limitation of cardiac cell therapy is low cell engraftment, the use of biodegradable scaffolds for specific homing and in situ cell retention is desirable. Thus, fibrin-based injectable cardiac tissue engineering may enhance cell therapy efficacy. Fibrin-based biomaterials can also be used for engineering heart valves or cardiac patches. The aim of this review is to show cardiac bioengineering uses of fibrin, both as a cell delivery vehicle and as an implantable biomaterial
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Significant endothelin release in patients treated with foam sclerotherapy
No full textBackground: Foam sclerotherapy has been proven to be a safe and effective treatment for superficial venous insufficiency, but transient visual and neurological disturbances continue to be reported. These side effects have been postulated to be related to the presence of air or gases in the sclerosing foam. We present a differing hypothesis where significant
Endothelin release from the treated varices is capable of generating such complications.
Material and methods: we have tested the release of Endothelin 1 in 12 rats where a sclerotherapy was performed with liquid or foamed sodium tetradecylsulphate. Moreover
we have measured Endothelin 1 in the systemic circulation and in a draining vein from
the treated area in a group of 11 patients treated with foam sclerotherapy with
Lauromacrogol 400
Results: Rats treated with STS showed significant increase in ET 1 levels at 1 and five minutes after foam sclerotherapy. Patients treated with foam sclerotherapy showed
significant increase in ET 1 levels and this significantly correlated with local ET 1 levels.
Conclusions: Evidence of Endothelin 1 release after sclerotherapy represents a plausible relationship explaining neurological and visual disturbances
Human peripheral blood endothelial progenitor cells synthesize and express functionally active tissue factor
No full textINTRODUCTION: Endothelial progenitor cells are circulating cells able to home to sites of vascular damage and to contribute to the revascularization of ischemic areas. We evaluated whether endothelial progenitor cells synthesize tissue factor, a procoagulant protein also involved in angiogenesis.
MATERIALS AND METHODS: Endothelial progenitor cells were obtained from the peripheral blood mononuclear fraction of normal donors and cultured in endothelial medium supplemented with specific growth factors. The procoagulant activity expressed by cells disrupted by freeze-thaw cycles was assessed by a one stage clotting assay. Tissue factor mRNA expression was evaluated by RT-PCR.
RESULTS: Endothelial progenitor cells do not express procoagulant activity in baseline conditions. However, lipopolysaccharide induces the expression of procoagulant activity. The effect is dose-dependent and reaches statistical significance at 100 ng/mL lipopolysaccharide. Inhibition with an anti-tissue factor antibody and amplification of cDNA with primers based on the tissue factor sequence confirm the identity of this activity with tissue factor. The kinetics of tissue factor expression by endothelial progenitor cells is identical to that of human umbilical vein endothelial cells showing maximal activity within 4 hours, and then decreasing; in contrast, tissue factor expression by mononuclear cells lasts for longer times. Both 5,6-dichloro-beta D-ribofuranosyl-benzimidazole and cycloheximide prevented the expression of procoagulant activity. Stimulation of endothelial progenitor cells with tumor necrosis factor-alpha did not elicit any detectable procoagulant activity.
CONCLUSIONS: Endothelial progenitor cells can be stimulated by lipopolysaccharide to synthesize tissue factor. This protein might be involved in thrombotic phenomena and might contribute to endothelial progenitor cells related neovascularization
Endothelial progenitor cells in prehypertension
No full textBlood pressure within prehypertensive levels confers higher cardiovascular risk. As prehypertension is also an intermediate stage for full hypertension, a precocious intervention with lifestyle changes or drugs is therefore appealing. Endothelial injury and dysfunction are thought to contribute to cardiovascular risk in prehypertension. Endothelial progenitor cell impairment has been linked to endothelial dysfunction, atherosclerotic disease progression and cardiovascular events. A potential mechanism contributing to the heightened cardiovascular risk in prehypertension may be linked to abnormalities in endothelial progenitor cell number and/or function. Aim of this review is to be up to date about the recent work on the correlation between endothelial progenitor cells and prehypertension and the possible prevention, treatment, and control of this pathology. The effect of an approach based on dietary intervention on both blood pressure and endothelial progenitor cells will be also shown
Clinical Significance of Endothelial Progenitor Cells in Endothelial Dysfunction from Smoking
No full textUnfractionated and Low Molecular Weight Heparins Differentially Affect the Activation of Serine/Threonine Protein Kinase AKT
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