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.

Q: Context: We previously reported that human OA subchondral bone osteoblasts could be discriminated into two subpopulations identified by their levels of endogenous production (low [L] or high [H]) of PGE(2). Here, we investigated the OPG and RANKL expression levels, the histologic analysis of the subchondral bone as well as the osteoclast differentiation effect of osteoblasts on normal and both OA subpopulations (L and H), and further examined on the L OA osteoblasts the modulation of bone remodelling factors on the OPG and RANKL levels, as well as on the resorption activity.', 'Gene expression was determined using real-time PCR, PGE2 and OPG levels by specific ELISA, and membranous RANKL by flow cytometry. Histological observation of the subchondral bone was performed on human knee specimens. Osteoclast differentiation and formation was assayed by using the pre-osteoclastic cell line RAW 264.7. OPG and RANKL modulation on L OA osteoblasts was monitored following treatment with osteotropic factors, and the resorption activity was studied by the co-culture of differentiated PBMC/osteoblasts.', 'Human OA subchondral bone osteoblasts expressed less OPG than normal. Compared to normal, RANKL gene expression levels were increased in L OA and decreased in H OA cells. The OPG/RANKL mRNA ratio was significantly diminished in L OA compared to normal or H OA (p<0.02, p<0.03), and markedly increased in H OA compared to normal. Inhibition of endogenous PGE(2) levels by indomethacin markedly decreased the ratio of OPG/RANKL on the H OA. In contrast to H OA osteoblasts, L OA cells induced a significantly higher level of osteoclast differentiation and formation (p<0.05). Histological analysis showed a reduced subchondral bone on the L OA and an increased bone mass on the H OA compared to normal. Treatment of L OA osteoblasts with osteotropic factors revealed that the OPG/RANKL mRNA expression ratio was significantly reduced by vitamin D(3) and significantly increased by TNF-alpha, PTH and PGE(2), while IL-1Beta demonstrated no effect. OPG protein levels showed similar profiles. No true effect was noted on membranous RANKL upon treatment with IL-1Beta, PGE(2) and PTH, but a significant increase was observed with vitamin D3 and TNF-alpha. The resorption activity of the L OA cells was significantly inhibited by all treatments except IL-1Beta, with maximum effect observed with vitamin D(3) and PGE(2).\Question: Is the differential expression of osteoprotegerin ( OPG ) and receptor activator of nuclear factor kappaB ligand ( RANKL ) in human osteoarthritic subchondral bone osteoblasts an indicator of the metabolic state of these disease cells?

A: OPG and RANKL levels, and consequently the OPG/RANKL ratio, differed according to human OA subchondral bone osteoblast classification; it is decreased in L and increased in H OA. These findings, in addition to those showing that L OA osteoblasts have a reduced subchondral bone mass and induce a higher level of osteoclast differentiation, strongly suggest that the metabolic state of the L OA osteoblasts favours bone resorption.
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Q: Context: Re-stenosis after percutaneous coronary angioplasty (PTCA) is related to clinical and angiographic features.', 'To describe the clinical and angiographic characteristic of our patients with coronary cardiopathy subjected to PTCA and the predictor factors for re-stenosis.', 'We gathered the clinical and angiographic characteristics of all patients who underwent a successful PTCA of a native coronary artery. All patients had a clinical assessment one year after the procedure. Patients were classified in Group 1, if they did not have angina or coronary events after the angioplasty or Group 2, if they had angina or a coronary event after the procedure. Only Group 2 patients were subjected to a coronary angiogram.', 'We collected 383 PTCA procedures. Follow up information was obtained in 92.2%. Three hundred forty two patients (89.3%) were assessed one year the procedure. Nine patients (2.3%) died of a cardiovascular cause. Ninety patients (26.3%) were classified in Group 2. In 65 patients, angiographic re-stenosis was demonstrated (19%). Re-stenosis occurred in 36 and 13% of patients with an without Diabetes Mellitus, respectively (p <0.01). The other clinical predictor variables were a history of myocardial infarction (p =0.007), obesity (p =0.041) and hypercholesterolemia (p =0.050). None of the angiographic characteristics predicted restenosis. Stents were protective factors against restenosis (15.6% in stented lesions vs 25.4% in nonstented; p =0.01).\Question: Do [ One year follow up of successful coronary angioplasty in non selected patients ]?

A: Re-stenosis after angioplasty occurred in 19% of our patients with angina or coronary events. The clinical variables associated with a higher risk of re-stenosis were diabetes (the main risk factor), previous myocardial infarction, obesity and hypercholesterolemia. Angiographic variables were not associated with re-stenosis. The use of stents decreases the incidence of re-stenosis in all groups).
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Q: Context: OLT is the best alternative for patients with end-stage liver diseases. However, as the need for organs surpasses donor availability, alternatives to OLT are required. LCT could be a useful option versus OLT in several patients even though its low cell-engraftment hampers its efficiency. Endothelial cell barrier is the main obstacle for the implantation of cells into the parenchyma. Our study has focused on the modification of the endothelial barrier with monoclonal antibodies against adhesion molecules in order to increase cell engraftment in a mouse model of liver cell transplantation.', 'Anti-mouse CD54 and anti-mouse CD61 antibodies were administered intrasplenically to healthy mice within 60 min prior to stem cell transplantation. Animals were sacrificed either short term at 2h or middle term seven days after transplantation. Immunohistochemical techniques to detect alkaline phosphatase activity were used to identify the transplanted cells within the liver parenchyma.', 'Anti-CD54 and anti-CD61 administration increases vascular patency and cell engraftment. This represents a 32% and 45% increase, respectively, of engrafted cells compared to the control (p<0.05).\Question: Does blockade of cell adhesion molecules enhance cell engraftment in a murine model of liver cell transplantation?

A:
Modification of the vascular wall with monoclonal antibodies against endothelial adhesion molecules before cell transplantation enhances cell engraftment into the mouse liver.
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