Given a passage, 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.
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Question: 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.

Answer: Does high-density lipoprotein stimulate endothelial cell migration and survival through sphingosine 1-phosphate and its receptors?


Question: Studies performed in Andean populations living in high altitude, indicate that the reduced availability of oxygen could be associated to both a fetal growth retardation and a lower birth weight. These variables are predictive of morbidity and mortality during the first year of life.', 'To study perinatal variables of newborns of mothers living at contrasting altitudinal levels, harboring different degrees of Aymara ancestry.', 'Review of medical records of 5,295 women whose deliveries occurred between February 2004 and August 2010. Information was obtained on place of residence, grouped into two categories: coast (150 to 3,000 m) and high plateau (3,000 to 4,300 m), ancestry was estimated using number of Aymara surnames that were homologated to percentages of Amerindian admixture, gestational age, birth weight, height, head circumference and obstetric variables.', 'Gestational age showed a tendency to increase and birth weight, height and head circumference to decrease with altitude of residence. Only weight reached statistical significance. Women with Aymara ancestry gave birth to children with a significantly higher gestational age, weight and cranial circumference.

Answer: Do [ Perinatal variables from newborns of Aymara mothers suggest a genetic adaptation to high altitude ]?


Question: Sildenafil (Viagra), an oral treatment for erectile dysfunction, has proved popular since its introduction in 1998. However, not all patients respond to this form of therapy. Consequently, this study investigated the efficacy of intracavernous alprostadil alfadex (EDEX/VIRIDAL) treatment in patients not responding to sildenafil.', 'In an open-label, multicenter study, patients with erectile dysfunction were treated with sildenafil for 4 weeks. The initial dose was 50 mg, which was increased to 100 mg if no response was achieved. Patients not responding to treatment, measured using the International Index of Erectile Function (IIEF) questionnaire, entered an alprostadil alfadex in-office titration phase, to determine the optimal dose, up to 40 microgram. A 6-week alprostadil alfadex at-home treatment phase followed.', 'In 67 patients who did not respond satisfactorily to sildenafil, the alprostadil alfadex at-home therapy resulted in improvements in questions 3 and 4 of the IIEF in 60 (89.6%) and 57 (85.1%) patients, respectively. The mean improvement in IIEF score for these patients was 2.75 and 2.63 for questions 3 and 4, respectively. The most common side effect was penile pain in 25 (29. 4%) of 85 patients treated with alprostadil alfadex in-office and at home.

Answer:
Is intracavernous alprostadil alfadex ( EDEX/VIRIDAL ) effective and safe in patients with erectile dysfunction after failing sildenafil ( Viagra )?