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 Q]: Context: Pulmonary vein (PV) isolation is a curative treatment for patients with atrial fibrillation. The aim of this study was to evaluate prospectively the effects of adenosine administration on the PV activity and atrio-venous conduction after PV isolation.', 'Twenty-nine patients (21 m; age: 55+/-8 years) were submitted to ostial PV isolation guided by basket catheter recordings. After successful isolation, the effects of a 12 mg intravenous bolus of adenosine were tested in 62 PVs. In 22/62 PVs (35%), left atrium (LA)-to-PV conduction was transiently (16.6+/-7.1 s, range: 3.8-27.9 s) or permanently (3 PVs) restored in response to adenosine administration. The prevalence of this phenomenon was 39% in left superior PVs, 43% in right superior PVs, and 22% in left inferior PVs (p=0.365). It occurred more frequently in the presence of dissociated PV activity (11/15 PVs, 73% vs. 11/47 PVs, 23%; p=0.002), whereas it was not influenced by the median duration of the radiofrequency current (RFC) delivery for each PV [19 (IQR: 12-26) min vs. 16 (IQR: 11-24) min: p=0.636]. A lengthening or shortening of the LA-PV conduction time was observed at LA-PV conduction appearance and disappearance in 36% and 55% of the cases, respectively. Further RFC applications (median: 5.5 min, IQR: 4-11 min) at the residual conduction breakthrough(s) indicated by the basket catheter recordings definitively eliminated adenosine-induced recovery of LA-PV conduction in all cases. Finally, when present, intrinsic PV discharge was invariably depressed by adenosine administration.
Answer: Adenosine may transiently or permanently re-establish LA-PV conduction after apparently successful PV isolation. This phenomenon is abolished by additional RFC delivery. However, its possible influence on the clinical results of PV ablation must be evaluated by properly designed, randomized studies.
[EX A]: Does adenosine restore atrio-venous conduction after apparently successful ostial isolation of the pulmonary veins?

[EX Q]: Context: To observe pharmacological difference between ultra-fine particles of six ingredient Rehmannia pill and traditional six ingredient Rehmannia pill.', 'Pharmacokinetic index was measured by death rate, and pharmacology actions were compared by anti-fatigue, hypoglycemic, clearance rate of charcoal particle, hypoxia resistance and serum hemolysin concentration experiment.', 'Dose-effection was significant and pharmacology actions were more than traditional six ingredient Rehmannia pill in six ingredient Rehmannia pill.
Answer: Ultra-fine particles of six ingredient Rehmannia pill are better than traditional six ingredient Rehmannia pill in bioavailability and pharmacology actions, and the weight of pill is reduced while efficacy is enhenced by ultra-fine particles.
[EX A]: Do [ Study on pharmacology of ultra-fine particles compound Rehmannia ]?

[EX Q]: 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.
Answer: HDL-induced endothelial cell migration and survival may be mediated by the lipoprotein component S1P and the lipid receptors S1P1 and S1P3.
[EX A]:
Does high-density lipoprotein stimulate endothelial cell migration and survival through sphingosine 1-phosphate and its receptors?