963 resultados para Microvascular Angina


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By using perfusions and bolus administration, coupled with postembedding immunocytochemical procedures, we have identified the structures involved in the transport of derivatized orosomucoid (α1-acidic glycoprotein) across the continuous microvascular endothelium of the murine myocardium. Our findings indicate that: (i) monomeric orosomucoid binds to the luminal surface of the endothelium; (ii) it is restricted to caveolae during its transport across the endothelium; (iii) it is detected in the perivascular spaces at early time points (by 1 min) and in larger quantities at later time points (>5 min) from the beginning of its perfusion or its intravascular administration; (iv) no orosomucoid molecules are found in the intercellular junctions or at the abluminal exits of interendothelial spaces; and (v) the vesicular transport of orosomucoid is strongly inhibited by N-ethylmaleimide (>80%). Because, by size and shape, the orosomucoid qualifies as a preferential probe for the postulated small pore system, our results are discussed in relation to the pore theory of capillary permeability.

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The sequence of events that leads to tumor vessel regression and the functional characteristics of these vessels during hormone–ablation therapy are not known. This is because of the lack of an appropriate animal model and monitoring technology. By using in vivo microscopy and in situ molecular analysis of the androgen-dependent Shionogi carcinoma grown in severe combined immunodeficient mice, we show that castration of these mice leads to tumor regression and a concomitant decrease in vascular endothelial growth factor (VEGF) expression. Androgen withdrawal is known to induce apoptosis in Shionogi tumor cells. Surprisingly, tumor endothelial cells begin to undergo apoptosis before neoplastic cells, and rarefaction of tumor vessels precedes the decrease in tumor size. The regressing vessels begin to exhibit normal phenotype, i.e., lower diameter, tortuosity, vascular permeability, and leukocyte adhesion. Two weeks after castration, a second wave of angiogenesis and tumor growth begins with a concomitant increase in VEGF expression. Because human tumors often relapse following hormone–ablation therapy, our data suggest that these patients may benefit from combined anti-VEGF therapy.

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Objective: To determine whether tight control of blood pressure prevents macrovascular and microvascular complications in patients with type 2 diabetes.

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Objective: To determine whether tight control of blood pressure with either a β blocker or an angiotensin converting enzyme inhibitor has a specific advantage or disadvantage in preventing the macrovascular and microvascular complications of type 2 diabetes.

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Treatment of cultured bovine brain microvascular endothelial cells (BMECs) with interleukin 1 beta (IL-1 beta), an inflammatory cytokine, was shown to induce the accumulation of sulfoglucuronosyl paragloboside (SGPG), a glycolipid bearing the HNK-1 epitope. This resulted in the attachment of a greater number of human lymphocytes to the treated than to the untreated BMEC monolayers. Attachment of human lymphocytes to the IL-1 beta-activated BMEC cells could be blocked either by incubation of the human lymphocytes with an anti-L-selectin antibody or by application of an anti-SGPG antibody to the BMECs. These results suggest that SGPG may act as an important ligand for L-selectin for the regulation of the attachment of activated lymphocytes and their subsequent invasion into the nervous system parenchyma in inflammatory disorders of the central and peripheral nervous systems.

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Tumour progression is a complex process that frequently brings to cancer metastasis, the first cause of poor prognosis of cancer affected patients. Metastasis are generated by cells escaped from a primary mass and able to enter in the circulation, survive and proliferate in a new, distant site of the organism. To reach all these goal, many different phenomena had occur within both the cancer cells and the surrounding microenvironment. In the first part of this thesis, the focus was pointed on the metastatic potential of a leiomyosarcoma cell model. The studied cancer cells demonstrated a strong invasive capacity of the ECM in vitro, principally by production of matrix metalloproteinases 2 and 9, and robust pro-angiogenic activity in the chick CAM model, that facilitate its dissemination through same chick embryo internal organs. This study, with the title “MMPs and angiogenesis affect the metastatic potential of a human vulvar leiomyosarcoma cell line”, is presented in the published form. In the second part of this work, the emphasis was given to the microvascular element of the tumour microenvironment and specifically to the perivascular pericytes. These are intriguing cells due to their uncertain involvement in the biology of cancer. It is not clear how pericytes change within the tumour microenvironment and which is their contribute during the tumour dissemination. After the characterization of the chosen pericytic cell model, an in vitro study of the interaction between pericytes and different cancer cell lines where performed. Indirect and direct cell-cell interaction as well as movement of cancer cells in presence of pericytes conditioned media was analysed, in order to investigate the reciprocal influence of pericytes and tumour cells in the context of cancer progression.

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Mode of access: Internet.

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Mode of access: Internet.

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Mode of access: Internet.