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: To study the role of peroperative transrectal ultrasonography (peTRUS) for the dissection of the bladder neck during robot-assisted laparoscopic prostatectomy (RALP).', 'Integrated peTRUS in the da Vinci S system (Intuitive Surgical, Sunnyvale, CA, USA) was used for bladder neck identification and dissection in the initial 80 patients with clinically localized prostate cancer operated by two urologists. The clinical and pathological results were compared with the initial 80 patients who had RALP with no peTRUS. The location of positive margins was recorded.', "The operative duration, blood loss, hospital stay, catheter dependency, clinical and pathological T-stage and Gleason sum score were no different between the groups. The prostate-specific antigen level at time of diagnosis was slightly higher for patients in the peTRUS group. Basal surgical margins (bladder neck and basal areas of both prostate lobes) were positive for tumour in 9.1% and 2.3% of patients treated without and with peTRUS, respectively (P = 0.001). Although the use of peTRUS improved the basal margin rate in the initial 30 patients in each group, it did not in the last 30 in each group, when the urologist's experience apparently improved. In a multivariate analysis the use of peTRUS and pathological T-stage were the best predictors of basal margin status. Pad use at 6 months after surgery was similar for both groups.
Answer: peTRUS during RALP decreased the positive surgical margin rate at the base of the prostate during the initial experience of RALP.

Ex Output:
Does peroperative transrectal ultrasonography-guided bladder neck dissection ease the learning of robot-assisted laparoscopic prostatectomy?


Ex Input:
Context: We evaluated the impact of impermeable bed covers on asthma in asthmatics with clinically relevant house dust mite (HDM) sensitization.', 'The study included 32 HDM-sensitized asthmatics in whom HDM allergy was considered as a significant factor in their asthma. They were randomized into either an intervention group whose bedding was encased with impermeable covers, or a control group who received cotton covers. Before and 3 and 6 months after encasement, dust samples were collected from the bedding and assayed for Der p 1. Clinical outcomes included quality of life, lung function, bronchial reactivity to methacholine, symptoms, medications and peak flow rates.', 'Baseline Der p 1 levels in both the active and the placebo groups were comparable and high (19.2 vs 18.9 microg/g of dust). There was a significant reduction in Der p 1 levels in the active group after 6 months, but not in the placebo group (7.3 vs 21.9 microg/g of dust). Quality of life improved significantly in both the intervention and control groups, but there was no significant difference in the improvements between the groups. There was no significant change in lung function, symptoms, and requirements for medications.
Answer: Encasement of bedding significantly reduced the Der p 1 levels. However, this was not sufficient to produce worthwhile clinical improvement in those in whom dust mite avoidance might well have been recommended as part of their clinical management.

Ex Output:
Does encasement of bedding improve asthma in atopic adult asthmatics?


Ex Input:
Context: To study the blood-brain barrier integrity in prehepatic portal hypertensive rats induced by partial portal vein ligation,at 14 and 40 d after ligation when portal pressure is spontaneously normalized.', 'Adult male Wistar rats were divided into four groups: Group I: Sham14d , sham operated; Group II: PH14d , portal vein stenosis; (both groups were used 14 d after surgery); Group III: Sham40d, Sham operated and Group IV: PH40d Portal vein stenosis (Groups II and IV used 40 d after surgery). Plasma ammonia,plasma and cerebrospinal fluid protein and liver enzymes concentrations were determined. Trypan and Evans blue dyes, systemically injected,were investigated in hippocampus to study blood-brain barrier integrity. Portal pressure was periodically recorded.', 'Forty days after stricture, portal pressure was normalized, plasma ammonia was moderately high, and both dyes were absent in central nervous system parenchyma. All other parameters were reestablished. When portal pressure was normalized and ammonia level was lowered, but not normal, the altered integrity of blood-brain barrier becomes reestablished.
Answer: The impairment of blood-brain barrier and subsequent normalization could be a mechanism involved in hepatic encephalopathy reversibility.Hemodynamic changes and ammonia could trigger blood-brain barrier alterations and its reestablishment.

Ex Output:

Does altered blood-brain barrier permeability in rats with prehepatic portal hypertension turn to normal when portal pressure is lowered?