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.

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.
Is transfemoral aortic valve implantation of Edwards SAPIEN XT without predilatation feasible?

Context: To evaluate pain behavior and structural damage in mice subjected to either meniscal transection or removal.', 'Mice (10/group) were subjected to transection of the medial collateral and anterior cruciate ligaments (ACLT/MCLT) followed by either transection (meniscotomy) or removal (meniscectomy) of the medial meniscus. A control group was subjected only to transection of the ligaments. Pain was assessed using the electronic pressure-meter paw test. Cell influx, measured in joint exudates, and joint histopathology were assessed after 49 days. Four other groups subjected to meniscotomy received indomethacin, the inducible nitric oxide synthase (iNOS) inhibitor 1400W, morphine or the vehicles.', 'Both meniscotomy and meniscectomy groups displayed persistent and significant increase in pain behavior as compared to controls, being significantly more severe in the former. Cell influx was more intense in the meniscotomy as compared to the meniscectomy group. Structural damage at the tibia, but not at the femur, was also more severe in the meniscotomy group. Indomethacin and 1400W partially but significantly reduced pain whereas morphine abrogated pain behavior in meniscotomized mice.
Answer: Meniscal transection rather than resection promotes more severe pain and structural damage in mice. Administration of opioids, cyclooxygenase and nitric oxide (NO) synthase inhibitors provide analgesia in this model. Careful description of the structures damaged is crucial when reporting experimental osteoarthritis (OA).
Does meniscal transection rather than excision increase pain behavior and structural damage in experimental osteoarthritis in mice?

Context: Psoriasis is a chronic inflammatory skin disorder associated with a host of immune abnormalities. Mesenchymal stem cells (MSCs) have immunosuppressive properties and, in earlier studies, we found that the bone marrow MSCs of patients with psoriasis exhibit abnormal cytokine secretion. Since MSCs can be isolated from skin, we hypothesized that the biological characteristics of MSCs in psoriatic skin lesions might reflect the pathogenesis of psoriasis.', 'To investigate the effects of MSCs from psoriatic skin lesions on T-cell proliferation.', 'MSCs obtained from psoriatic skin lesions and healthy human skin were examined by flow cytometry and cell differentiation assays. MSCs were co-cultured with normal peripheral blood T cells to assess changes in T-cell proliferation. Concentrations of interleukin (IL)-6, IL-11, hepatocyte growth factor (HGF), and transforming growth factor (TGF)-β1 in the MSC culture supernatants were measured by enzyme-linked immunosorbent assays.', 'Surface markers and differentiation capacity were similar in MSCs from both sources. MSCs in psoriatic skin lesions were weaker inhibitors of T-cell proliferation (p<0.05) and exhibited increased secretion of IL-11 and reduced secretion of IL-6 and HGF (p<0.05). Secretion of TGF-β1 was unchanged (p > 0.05).
Answer: This study demonstrated abnormalities in MSCs derived from psoriatic skin lesions. We suggest that the attenuated inhibitory effect on T-cell proliferation might be one of the pathogenic mechanisms of psoriasis.

Is lymphocyte inhibition compromised in mesenchymal stem cells from psoriatic skin?