TASK DEFINITION: In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
PROBLEM: Context: Patient-prosthesis mismatch has been identified as a risk factor for mortality after aortic valve replacement and for structural valve deterioration (SVD) in patients receiving a bioprosthetic aortic valve. The aim of the present study was to compare the incidence of aortic valve bioprosthesis replacement for SVD in patients with mismatch to a population without mismatch.', 'Three hundred eighty-seven adult patients who underwent aortic valve replacement with a bioprosthesis from 1974 to 2009 were retrospectively reviewed. Mismatch was considered to be present if the anticipated indexed effective orifice area was <0.70cm(2) /m(2) . The median follow-up period was 7.2 years. Follow-up was 97% complete.', "Patient-prosthesis mismatch was present in 12% of the study population (n=47). Ten-year freedom from reoperation for aortic bioprosthesis replacement was 74.33.2%. During follow-up, 111 patients underwent reoperation for aortic bioprosthesis replacement. Causes of aortic bioprosthesis replacement were SVD of the bioprosthesis (n=96), paravalvular leak (n=10), and acute endocarditis (n=5). According to unadjusted Kaplan-Meier analysis, patients with mismatch had a higher incidence of aortic bioprosthesis replacement for SVD when compared with patients without mismatch (log rank test: p 0.05). This result was confirmed by multivariable Cox regression analysis, which identified two independent predictors of aortic bioprosthesis replacement for SVD: patients' age (hazard ratio (HR) 0.967) and patient-prosthesis mismatch (HR 2.161).\Question: Does patient-prosthesis mismatch in patients undergoing bioprosthetic aortic valve implantation increase risk of reoperation for structural valve deterioration?

SOLUTION: Patients suffering from mismatch were twice as likely to undergo reoperation for aortic bioprosthesis replacement for SVD than those without mismatch.

PROBLEM: Context: Transport across the blood-brain barrier (BBB) is an important mediator of beta-amyloid (A) accumulation in the brain and a contributing factor in the pathogenesis of Alzheimer's disease (AD). One of the receptors responsible for the transport of A in the BBB is the low density lipoprotein receptor-related protein 1 (LRP1). LRP1 is susceptible to proteolytic shedding at the cell surface, which prevents endocytic transport of ligands. Previously, we reported a strong inverse correlation between LRP1 shedding in the brain and A transit across the BBB. Several proteases contribute to the ectodomain shedding of LRP1 including the -secretase, a desintegrin and metalloproteinase domain containing protein 10 (ADAM10).", 'The role of ADAM10 in the shedding of LRP1 and A BBB clearance was assessed through pharmacological inhibition of ADAM10 in an in vitro model of the BBB and through the use of ADAM10 endothelial specific knock-out mice. In addition, an acute treatment paradigm with an ADAM10 inhibitor was also tested in an AD mouse model to assess the effect of ADAM10 inhibition on LRP1 shedding and Abrain accumulation.', 'In the current studies, inhibition of ADAM10 reduced LRP1 shedding in brain endothelial cultures and increased A42 transit across an in vitro model of the BBB. Similarly, transgenic ADAM10 endothelial knockout mice displayed lower LRP1 shedding in the brain and significantly enhanced A clearance across the BBB compared to wild-type animals. Acute treatment with the ADAM10-selective inhibitor GI254023X in an AD mouse model substantially reduced brain LRP1 shedding and increased A40 levels in the plasma, indicating enhanced A transit from the brain to the periphery. Furthermore, both soluble and insoluble A40 and A42 brain levels were decreased following GI254023X treatment, but these effects lacked statistical significance.\Question: Does inhibition of ADAM10 promote the clearance of A across the BBB by reducing LRP1 ectodomain shedding?

SOLUTION: These studies demonstrate a role for ADAM10 in the ectodomain shedding of LRP1 in the brain and the clearance of A across the BBB, which may provide a novel strategy for attenuating A accumulation in the AD brain.

PROBLEM: Context: Interleukin-8 (IL-8), a CXC chemokine that induces the migration and proliferation of endothelial cells and smooth muscle cells, is a potent angiogenic factor that may play a role in atherosclerosis. Previously, IL-8 has been reported in atherosclerotic lesions and circulating macrophages from patients with atherosclerosis. Therefore, we sought to determine whether IL-8 plays a role in mediating angiogenic activity in atherosclerosis.', 'Homogenates from 16 patients undergoing directional coronary atherectomy (DCA) and control samples from the internal mammary artery (IMA) of 7 patients undergoing bypass graft surgery were assessed for IL-8 content by specific ELISA, immunohistochemistry, and in situ hybridization for IL-8 mRNA. The contribution of IL-8 to net angiogenic activity was assessed using the rat cornea micropocket assay and cultured cells. IL-8 expression was significantly elevated in DCA samples compared with IMA samples (1.71+/-0.6 versus 0.05+/-0.03 ng/mg of total protein; P<0.01). Positive immunolocalization of IL-8 was found exclusively in DCA tissue sections, and it correlated with the presence of factor VIII-related antigen. In situ reverse transcriptase polymerase chain reaction revealed the expression of IL-8 mRNA in DCA tissue. Corneal neovascular response, defined by ingrowth of capillary sprouts toward the implant, was markedly positive with DCA pellets, but no constitutive vessel ingrowth was seen with IMA specimens. Neutralizing IL-8 attenuated both the in vivo corneal neovascular response and the in vitro proliferation of cultured cells.\Question: Is iL-8 an angiogenic factor in human coronary atherectomy tissue?

SOLUTION:
The results suggest that, in human coronary atherosclerosis, IL-8 is an important mediator of angiogenesis and may contribute to plaque formation via its angiogenic properties.