6,963 publications from this institution
The history of intravascular ultrasound imaging, recent developments in catheter technology, and the initial in vivo experience are reviewed. Additionally, the article also discusses the potential applications of intravascular ultrasound imaging in coronary and peripheral arterial atherosclerosis, hypertension, pulmonary arterial disorders, valvular heart disease, aortic abnormalities, and in congenital heart disorders. Possible future directions are outlined.
Abstract Tissue Factor (TF) is a trans membrane glycoprotein important for initiation of the coagulation cascade. Recent observations indicate that TF is expressed in cancer, metabolic diseases and infections. In the current study, we determined the role of TF in M. tuberculosis (M. tb) infection using mice lacking the TF gene in myeloid cells (Cre+). One month after infection with the M. tb virulent laboratory strain, H37Rv, the lung bacterial burden was higher in Cre+ than Cre- mice (3.7 ± 0.2 X 106 vs 1.9 ± 0.1 X 106 CFU, p=0.01). M.tb infected Cre+ mice had more CD4+ and CD8+ lymphocytes and expressed 33 and 38 fold less of IFN-γ and IL-17 mRNA in the lungs, compared to Cre- mice, as measured by real time PCR. In contrast, lung IL-10 mRNA levels were higher in M. tb-infected Cre+ mice than Cre- mice (16.04 ± 3.3 vs 4.4 ± 1 fold, p=0.03). Immunohistochemical analysis indicated that M. tb-infected Cre+ mice had more foamy macrophages in the lungs than Cre- mice. M. tbH37Rv grew more rapidly in peritoneal exudate macrophages of Cre+ mice, compared to Cre- macrophages (6.1 ± 1 X 106 vs 1.5 ± 0.6 X 106 CFU, p=0.02). Further studies indicated that M. tb-infected Cre+ macrophages undergo less mitochondrial apoptosis than Cre- macrophages (16.2 ± 2.1vs 27.9 ± 1.4 %, p=0.01). Studies are underway to determine the mechanism/s involved in increased IL-10 production, reduced mitochondrial apoptosis and increased bacterial burden of M tb infected Cre+ mice.
Theophylline (3-methyxanthine) has been used to treat airway diseases for over 70 years. It was originally used as a bronchodilator but the relatively high doses required are associated with frequent side effects, so its use declined as inhaled β2-agonists became more widely used. More recently it has been shown to have anti-inflammatory effects in asthma and COPD at lower concentrations. The molecular mechanism of bronchodilatation is inhibition of phosphodiesterase(PDE)3 and PDE4, but the anti-inflammatory effect may be due to histone deacetylase (HDAC) activation, resulting in switching off of activated inflammatory genes. Through this mechanism theophylline also reverses corticosteroid resistance and this may be of particular value in severe asthma and COPD where HDAC2 activity is markedly reduced. Theophylline is given systemically (orally as slow-release preparations for chronic treatment and intravenously for acute exacerbations of asthma) and blood concentrations are determined mainly by hepatic metabolism, which may be increased or decreased in several diseases and by concomitant drug therapy. Theophylline is now usually used as an add-on therapy in asthma patients not well controlled on inhaled corticosteroids and in COPD patients with severe disease not controlled by bronchodilator therapy. Side effects are related to plasma concentrations and include nausea, vomiting and headaches due to PDE inhibition and at higher concentrations to cardiac arrhythmias and seizures due to adenosine A1-receptor antagonism.
Abstract Previously we found that regulatory T cells (CD4+CD25+Foxp3+ cells, Tregs) expand in response to M.tuberculosis (M. TB) through mechanism that depend on prostaglandin E2 production. In the current study, we determined the role of NK cells in regulating Tregs expansion in human M. TB infection. M. TB whole cell lysate (TB lysate) resulted in regulatory T cell expansion (15.33±1.02% vs 1.5±0.22%, P<0.001). Addition of monokine-activated NK cells (IL-12, IL-15 and IL-18) markedly inhibited Treg expansion (6.2±1.2% vs 15±1.5%, P<0.001) but freshly isolated NK cells had no effect. NK cells activated with TB lysate-stimulated monocytes also reduced Tregs expansion (13.2±0.3% to 3.4±1.4%, P<0.001) confirming the physiological relevance of this effect. Reduced Tregs expansion was not due to inhibition of PGE2 production or because of IFN γ. Monokine activated NK cells lysed TB lysate-expanded Tregs, but not freashly isolated Tregs (% specific lysis of 21±3% vs 1±1% P<0.001), nor T regs depleted T cells. Anti-NKG2D and anti-NKp46 reduced the % specific lysis of expanded Tregs from 22±3% to 7±3% and 8±3%, respectively (P<0.001) but abs to CD16, DNAM-1, and 2B4 had no effect. NKG2D ligand, ULBP1 expression was markedly upregulated on expanded T regs, compared to T regs depleted cells ( 31±5% vs 2.1 ±0.4%, P=0.002) and freshly isolated Tregs (4.6±1.1%). Anti -ULBP1 significantly inhibited the NK mediated lysis of expanded Tregs (specific lysis of 27±4% vs 9±2%, P<0.001) but abs to ULBP2, ULBP3 and MICA/B had no effect. These finding suggest that NK cells reduce the frequency of M.TB-expanded T regs by direct lysis.
Warfield’s views on the book of Genesis, evolution, race, and eugenics have also aroused much discussion. This article looks at each of these issues in turn, after first giving a general historical overview of Warfield’s life.
Wide clinical application of intravascular stenting devices is currently limited by occlusion or intraluminal narrowing caused by thrombosis and neointimal thickening in a considerable percentage of implantations. We studied the possibility of seeding one of the currently availiable stents, a stainless steel, self‐expandable wire‐mesh, with endothelial cells in vitro. Endothelial cells, derived from human umbilical cord veins, could be successfully attached to stent filaments. In vivo stent implantations in porcine femoral arteries showed complete covering of stent wires by endothelium after 1 week. We conclude that coating of stents with autologous endothelial cells prior to implantation might protect against early thrombosis during the period in which a neointima is formed. (J Interven Cardiol 1988:1:2)
No abstract is provided for this article.
An experimental study was conducted into the degree of composite action that can arise between cold-formed steel joists and wood-based flooring panels. A series of material, push-out and 4-point bending tests were carried out, and alternative means of shear connection, featuring fasteners and adhesives, were investigated. It was found that the spacing of the fasteners and the application of structural adhesive at the beam-board interface had a significant influence on the attained degree of shear connection and, hence, the moment capacity and flexural stiffness of the system. The highest degree of shear connection (up to approximately 60%) was obtained using the structural adhesive, bringing corresponding increases in capacity and stiffness of approximately 100 and 40%, respectively, over the bare steel. Smaller, but still very significant, increases in capacity and stiffness were achieved through the use of screws alone. On the basis of the results of the push-out tests, a load-slip relationship for screw fasteners in wood-based floorboards was proposed; this was designed for use in future analytical and numerical models. The findings of this research demonstrate, for the first time, the benefits that can be derived through the practical exploitation of composite action in cold-formed steel flooring systems in terms of enhanced structural performance and efficiency of material use.
No abstract is provided for this article.