Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Ex Input:
Context: Respiratory failure is a major complication after cardiac surgery. The purpose was to evaluate the impact of minimally invasive aortic valve replacement (mini AVR) on the occurrence of left lower lobe atelectasis (LLLA) in the cardiac intensive care unit (ICU).', '98 patients were scheduled to undergo mini AVR. 14 of these patients were converted to a full sternotomy due to technical problems. These patients were compared to a group of 50 patients having planned AVR through a full sternotomy. The incidence of LLLA was evaluated on the first postoperative chest X-ray in the cardiac ICU.', 'In the group having completed mini AVR 20/84 (24%) had a partial LLLA while in the group having extension to a full sternotomy 9/14 (64%) had LLLA lobe (P<0.005). In the group of 50 patients who had AVR through a full sternotomy, 27 patients (54%) had LLLA in the ICU which is also significantly higher (P<0.008) than the percentage of atelectasis in the mini AVR group.
Answer: Patients who had mini AVR had a significantly lower incidence of LLLA in the cardiac ICU than patients who had AVR through a full sternotomy.

Ex Output:
Does minimally invasive aortic valve replacement reduce atelectasis in cardiac intensive care?


Ex Input:
Context: Ischemic mitral regurgitation (MR) often persists after restrictive mitral valve annuloplasty, in which case it is associated with worse clinical outcomes. The goal of the present study was to determine whether persistence of MR and/or clinical outcome could be predicted from preoperative analysis of mitral valve configuration.', 'In 51 consecutive patients undergoing restrictive annuloplasty for ischemic MR, posterior leaflet (PL) angle, anterior leaflet angle, coaptation distance, and tenting area were quantified by echocardiography before surgery (6+/-3 days), and MR severity was assessed before and early after surgery (9+/-4 days). Postoperatively, persistence of mild to moderate MR (vena contracta > 3 mm) was observed in 11 (22%) of the patients. The best predictor of postoperative persistence of MR was a PL angle > or = 45 degrees (sensitivity 100%, specificity 97%, positive predictive value 92%, negative predictive value 100%). Patients with persistent MR had markedly lower 3-year event-free survival (26+/-20%) compared with those with nonpersistent MR (75+/-12%, P=0.01). Preoperative presence of a PL angle > or = 45 degrees also was associated with a markedly lower 3-year event-free survival (22+/-17% versus 76+/-12%; P<0.001).
Answer: In patients undergoing restrictive annuloplasty for ischemic MR, persistence of MR and 3-year event-free survival can accurately be predicted by preoperative analysis of mitral valve configuration. Patients with a PL angle > or = 45 degrees (ie, with high PL restriction) should thus be considered poor candidates for this procedure, and concomitant or alternative procedures should be contemplated.

Ex Output:
Does preoperative posterior leaflet angle accurately predict outcome after restrictive mitral valve annuloplasty for ischemic mitral regurgitation?


Ex Input:
Context: Patients with glioblastoma multiforme (GBM) have an overall median survival of 15 months. This catastrophic survival rate is the consequence of systematic relapses that could arise from remaining glioblastoma stem cells (GSCs) left behind after surgery. We previously demonstrated that GSCs are able to escape the tumor mass and specifically colonize the adult subventricular zones (SVZs) after transplantation. This specific localization, away from the initial injection site, therefore represents a high-quality model of a clinical obstacle to therapy and relapses because GSCs notably retain the ability to form secondary tumors.', 'In this work, we questioned the role of the CXCL12/CXCR4 signaling in the GSC-specific invasion of the SVZs.', 'We demonstrated that both receptor and ligand are respectively expressed by different GBM cell populations and by the SVZ itself. In vitro migration bio-assays highlighted that human U87MG GSCs isolated from the SVZs (U87MG-SVZ) display stronger migratory abilities in response to recombinant CXCL12 and/or SVZ-conditioned medium (SVZ-CM) compared with cancer cells isolated from the tumor mass (U87MG-TM). Moreover, in vitro inhibition of the CXCR4 signaling significantly decreased the U87MG-SVZ cell migration in response to the SVZ-CM. Very interestingly, treating U87MG-xenografted mice with daily doses of AMD3100, a specific CXCR4 antagonist, prevented the specific invasion of the SVZ. Another in vivo experiment, using CXCR4-invalidated GBM cells, displayed similar results.
Answer: Taken together, these data demonstrate the significant role of the CXCL12/CXCR4 signaling in this original model of brain cancer invasion.

Ex Output:

Do adult mouse subventricular zones stimulate glioblastoma stem cells specific invasion through CXCL12/CXCR4 signaling?