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.

Input: Consider Input: Context: Plasma high-density lipoprotein (HDL) level is inversely correlated with the risk of atherosclerosis. However, the cellular mechanism by which HDL exerts antiatherogenic actions is not well understood. In this study, we focus on the lipid components of HDL as mediators of the lipoprotein-induced antiatherogenic actions.', 'HDL and sphingosine 1-phosphate (S1P) stimulated the migration and survival of human umbilical vein endothelial cells. These responses to HDL and S1P were almost completely inhibited by pertussis toxin and other specific inhibitors for intracellular signaling pathways, although the inhibition profiles of migration and survival were different. The HDL-stimulated migration and survival of the cells were markedly inhibited by antisense oligonucleotides against the S1P receptors EDG-1/S1P1 and EDG-3/S1P3. Cell migration was sensitive to both receptors, but cell survival was exclusively sensitive to S1P1. The S1P-rich fraction and chromatographically purified S1P from HDL stimulated cell migration, but the rest of the fraction did not, as was the case of the cell survival.\Question: Does high-density lipoprotein stimulate endothelial cell migration and survival through sphingosine 1-phosphate and its receptors?

Output: HDL-induced endothelial cell migration and survival may be mediated by the lipoprotein component S1P and the lipid receptors S1P1 and S1P3.


Input: Consider Input: Context: To describe technical challenges encountered using the Ovation endograft for abdominal aortic aneurysms and suggest tips and maneuvers for successful management.', "Deployment of the Ovation's unsupported main body is often associated with the anteroposterior arrangement of the limb gates instead of the usual side-by-side configuration, rendering contralateral catheterization challenging. Successful catheterization of the contralateral limb can be confirmed by lateral deviation of the ipsilateral stiff guidewire caused by balloon inflation within the contralateral limb. Moreover, failure to cannulate the contralateral limb gate due to persistent impingement of the guidewire or compromise of the inflated rings can be overcome using the transbrachial antegrade approach.\Question: Does technical challenge encountered during deployment of the ovation abdominal aortic stent-graft system?

Output: Awareness of certain aspects associated with the use of the Ovation device and adoption of the adjunctive techniques herein described helps the interventionist avoid unexpected challenges or manage technical difficulties to maximize the device's safety and effectiveness.


Input: Consider Input: Context: Sphingolipids constitute bioactive molecules with functional implications in homeostasis and pathogenesis of various diseases. However, the role of sphingolipids as possible disease biomarkers in chronic liver disease remains largely unexplored. In the present study we used mass spectrometry and spectrofluorometry methods in order to quantify various sphingolipid metabolites and also assess the activity of an important corresponding regulating enzyme in the serum of 72 healthy volunteers as compared to 69 patients with non-alcoholic fatty liver disease and 69 patients with chronic hepatitis C virus infection. Our results reveal a significant upregulation of acid sphingomyelinase in the serum of patients with chronic liver disease as compared to healthy individuals (p<0.001). Especially in chronic hepatitis C infection acid sphingomyelinase activity correlated significantly with markers of hepatic injury (r=0.312, p=0.009) and showed a high discriminative power. Accumulation of various (dihydro-) ceramide species was identified in the serum of patients with non-alcoholic fatty liver disease (p<0.001) and correlated significantly to cholesterol (r=0.448, p<0.001) but showed a significant accumulation in patients with normal cholesterol values as well (p<0.001). Sphingosine, a further bioactive metabolite, was also upregulated in chronic liver disease (p<0.001). However, no significant correlation to markers of hepatic injury was identified.\Question: Is serum acid sphingomyelinase upregulated in chronic hepatitis C infection and non alcoholic fatty liver disease?


Output: Chronic hepatitis C virus infection and non-alcoholic fatty liver disease induce a significant upregulation of serum acid sphingomyelinase which appears as a novel biomarker in chronic hepatopathies. Further studies are required to elucidate the potential of the sphingolipid signaling pathway as putative therapeutic target in chronic liver disease.