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

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Context: To conduct clinical and genetic studies in a European family with autosomal dominant Stargardt-like macular dystrophy (adSTGD-like MD) and to investigate the functional consequences of a novel ELOVL4 mutation.', 'Ophthalmic examination and mutation screening by direct sequencing of the ELOVL4 gene was performed in two affected individuals. Wild-type and mutant ELOVL4 genes were expressed as enhanced green fluorescent protein (EGFP) fusion proteins in transient transfection in NIH-3T3 and HEK293 cells. To determine the subcellular localization of ELOVL4, an endoplasmic-reticulum (ER)-specific marker for pDsRed2-ER was cotransfected with ELOVL4 constructs. Transfected cells were viewed by confocal microscopy. Western blot analysis was performed to assess protein expression using an anti-GFP antibody.', 'Affected patients exhibited macular atrophy with surrounding flecks characteristic of adSTGD-like MD. A novel ELOVL4 p.Tyr270X mutation was detected in affected individuals. In cell-transfection studies, wild-type ELOVL4 localized preferentially to the ER. In contrast, the mutant protein appeared to be mislocalized within transfected cells.
Answer: In a European family with adSTGD-like MD, a novel ELOVL4 mutation was found to underlie the disorder. Transfection studies indicated that, unlike wild-type ELOVL4, the mutant protein does not localize to the ER but rather appears to be sequestered elsewhere in an aggregated pattern in the cytoplasm. Further analysis of the function of normal and mutant ELOVL4 will provide insight into the mechanism of macular degeneration.
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Does a novel mutation in the ELOVL4 gene cause autosomal dominant Stargardt-like macular dystrophy?

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Context: To determine the influence of ketamine on endotoxin-induced leukocyte adherence and venular microhemodynamics.', 'Randomized, controlled trial.', 'Experimental laboratory.', 'Thirty male Wistar rats.', 'The rats were pretreated with ketamine (10 mg/kg iv) or 0.9% saline, and both groups were given endotoxin (Escherichia coli lipopolysaccharide; 5 mg/kg iv). The control group received two doses of 0.9% saline.', 'The rates of leukocyte adherence and changes in microhemodynamics were monitored in rat mesenteric venules, using in vivo video microscopy. The number of adherent leukocytes was determined on-line in 10-min intervals from 60 mins before until 2 hrs after endotoxin administration. Venular diameters, red blood cell velocity, volumetric blood flow, and the venular wall shear rate were monitored before and at 10, 30, and 60 mins after endotoxin exposure. A 6.3-fold increase in the number of adherent leukocytes was observed 10 mins after administration of endotoxin when compared with control animals (5.87 +/- 0.69 vs. 0.93 +/- 0.21 adherent cells/100 microns; p < .001). This increase remained unchanged for 120 mins. In ketamine-pretreated rats, a 2.6-fold increase in leukocyte adherence occurred during the first 20 mins after endotoxin exposure (2.40 +/- 0.46 vs. 0.93 +/- 0.21 adherent cells/100 microns; p < .01). However, no difference in the number of adherent leukocytes between ketamine-pretreated and control animals was found after this 20-min period. In animals of the control group, no increase in leukocyte adherence occurred during the entire observation time. Diameters of mesenteric venules did not change after endotoxin exposure in any of the groups. Red blood cell velocity and venular blood flow in the endotoxin-treated groups decreased 10 mins after the injection of endotoxin when compared with controls, but these values did not show any difference when they were compared between ketamine and saline-pretreated animals. Similarly, venular wall shear rate in the endotoxin-treated groups decreased 10 and 30 mins after injection of endotoxin. However, no significant difference occurred between ketamine and saline-pretreated animals.
Answer: Pretreatment with ketamine attenuates endotoxin-induced leukocyte adherence by a shear rate-independent mechanism, suggesting reduced expression of adhesion molecules. These results indicate that ketamine exerts an anti-inflammatory effect, which might be beneficial in septic patients.
answer:
Does ketamine attenuate endotoxin-induced leukocyte adherence in rat mesenteric venules?