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.

[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.
[A]: Does adenosine restore atrio-venous conduction after apparently successful ostial isolation of the pulmonary veins?


[Q]: Context: In patients with moderate-to-severe psoriasis, health-related quality of life (HRQOL) has been shown to improve in parallel with improvement in disease severity.', 'To evaluate the role of pruritus (itch) in mediating the relationship between improvements in disease severity and HRQOL.', 'Data from a phase 2 clinical trial, in which 142 patients with moderate-to-severe plaque psoriasis received ixekizumab or placebo, were used for this posthoc analysis. Relationships between improvement in Psoriasis Area and Severity Index (PASI), Itch Visual Analogue Scale (VAS) and Dermatology Life Quality Index (DLQI), as well as in individual DLQI domains (symptoms and feelings, treatment, work and school, daily activities, leisure, and personal relationships) from baseline to week 16 were determined. Multiple hierarchical linear regressions and Sobel tests were conducted to evaluate the results.', 'Improvement in PASI was highly correlated with pruritus improvement and improvements in DLQI total and domain scores at week 16 (P\xa0<\xa00·01). Multiple hierarchical linear regression analyses showed a statistically significant (P\xa0<\xa00·01) association between improvement in pruritus and improvement in DLQI total score and each of the six DLQI domain scores after adjusting for improvement in PASI. Sobel tests indicated that pruritus had a significant mediation effect (P\xa0<\xa00·05) on the association of PASI improvement with improvement in DLQI total score and all domains except the personal relationships score.
Answer: Pruritus appears to be an important mediator of the association between improvements in disease severity and HRQOL in patients with moderate-to-severe psoriasis.
[A]: Is itching a significant problem and a mediator between disease severity and quality of life for patients with psoriasis : results from a randomized controlled trial?


[Q]: Context: Computed tomography (CT) is an imaging modality involving ionizing radiation. The presence of γ-H2AX foci after low to moderate ionizing radiation exposure has been demonstrated; however it is unknown whether very low ionizing radiation exposure doses from CT exams can induce γ-H2AX formation in vivo in young children.', 'To test whether very low ionizing radiation doses from CT exams can induce lymphocytic γ-H2AX foci (phosphorylated histones used as a marker of DNA damage) formation in vivo in young children.', 'Parents of participating children signed a consent form. Blood samples from three children (ages 3-21\xa0months) undergoing CT exams involving very low blood ionizing radiation exposure doses (blood doses of 0.22-1.22\xa0mGy) were collected immediately before and 1\xa0h post CT exams. Isolated lymphocytes were quantified for γ-H2AX foci by a technician blinded to the radiation status and dose of the patients. Paired t-tests and regression analyses were performed with significance levels set at P\u2009<\u20090.05.', 'We observed a dose-dependent increase in γ-H2AX foci post-CT exams (P\u2009=\u20090.046) among the three children. Ionizing radiation exposure doses led to a linear increase of foci per cell in post-CT samples (102% between lowest and highest dose).
Answer: We found a significant induction of γ-H2AX foci in lymphocytes from post-CT samples of three very young children. When possible, CT exams should be limited or avoided by possibly applying non-ionizing radiation exposure techniques such as US or MRI.
[A]:
Are γ-H2AX foci increased in lymphocytes in vivo in young children 1 h after very low-dose X-irradiation : a pilot study?