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: Androgen-independent prostate cancer is today an incurable disease, but increased understanding of the mechanisms for the transition into an androgen-independent state may increase the possibilities for more efficient strategies in the future.', 'An androgen-independent subline, LNCaP-19, to the androgen-dependent prostate cancer cell line LNCaP was developed in vitro under standard culture conditions. The characteristics of LNCaP-19 regarding androgen responsiveness, PSA, and VEGF secretion was studied in vitro. The growth in vivo and the microvessel density (MVD) of the tumors were studied after inoculation in nude mice.', 'LNCaP-19 grows equally well in dextran-charcoal stripped FBS (DCC-FBS) as in normal FBS, and rapidly gives rise to tumors in both intact and castrated mice, indicating a true androgen-independent growth. The PSA secretion from LNCaP-19 cells was lower than from LNCaP cells, while the VEGF level was comparable to the secretion from LNCaP cells without androgen stimulation. The MVD was increased in the LNCaP-19 tumors, and the vessels also displayed a changed morphology with exclusively small microvessels without lumen.
Answer: LNCaP-19 shows characteristics resembling those of androgen-independent prostate cancer. An increased MVD and changed vessel morphology in the tumor, makes it an interesting model system for studies regarding angiogenesis in the context of the acquisition of androgen independence.
[EX A]: Is transition of an androgen-dependent human prostate cancer cell line into an androgen-independent subline associated with increased angiogenesis?

[EX Q]: Context: To assess the role of whole-body computed tomography (CT) for determining morphological suitability before multiorgan retrieval (MOR) in brain dead patients.', 'Fifty-one clinically brain dead patients (21 women, 30 men; mean age 61 year±15) were included in this prospective, single center study. All patients had CT angiography of the brain and whole-body CT examination. CT images were evaluated for the presence of morphological abnormalities of lungs, liver and other abdominal organs and presence of vascular anatomical variants. The results of CT examinations were compared to intraoperative findings observed during organ harvesting and/or the results of histopathological analysis of biopsy specimens. The impact of whole-body CT examination on the harvesting process was evaluated.', 'Ninety-five percent of vascular anatomical variants that were found intraoperatively were depicted on CT. CT density measurements predicted surgical finding of steatosis in 80% of patients. Whole-body CT changed the MOR strategy in 21/51 patients (41%) including 3 MOR cancellations and 8 grafts refusals, whereas organ harvesting was continued in 10 patients after histopathological analysis was performed.
Answer: Selection of potential graft donors using whole-body CT is reliable and improves graft selection during MOR.
[EX A]: Is simultaneous CT angiography and whole-body CT an effective imaging approach before multiorgan retrieval?

[EX Q]: Context: Transcatheter aortic valve implantation (TAVI) without predilatation has fewer procedural steps and thereby potentially fewer complications. This has been demonstrated for the antegrade transapical access; however, whether TAVI can be safely performed without predilatation using the retrograde transfemoral route is unknown.', 'We postulated that TAVI is feasible with a balloon-expandable device without predilatation using the retrograde transfemoral route.', 'Twenty-six consecutive patients with stenosis of the native aortic valve (AV) undergoing transfemoral TAVI with the Edwards SAPIEN XT prosthesis without predilatation were enrolled in this retrospective study and compared with 30 patients treated previously with predilatation.', 'The procedure was successfully performed in all 26 patients, irrespective of the AV area and the extent of AV calcification. At baseline mean AV area, mean AV gradient, and median left ventricular ejection fraction were 0.7 ± 0.2 cm(2) , 36.0 ± 17.3 mm Hg, and 55.0% (interquartile range [IQR], 35.0-60.0], respectively; prior to discharge these values were 1.7 ± 0.3 (P < 0.001), 9.8 ± 6.1 mm Hg (P < 0.001), and 57.5% (IQR, 38.7-60.0) (P = not significant). Postdilatation was required in 3 patients due to aortic regurgitation > 2°; this was reduced by the procedure to < 2° in all cases. Radiation dose and amount of contrast dye were significantly reduced in comparison with the predilatation group. No periprocedural neurological adverse events occurred. Mortality at 30 days was 0%.
Answer: TAVI without predilatation using the transfemoral Edwards SAPIEN XT valve is feasible and safe. Larger studies are required to further evaluate this approach.
[EX A]:
Is transfemoral aortic valve implantation of Edwards SAPIEN XT without predilatation feasible?