Given a passage, 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.

Input: Consider Input: The 6-min walk test (6MWT) has prognostic value in various pulmonary disorders including idiopathic pulmonary fibrosis (IPF). We determined the individual prognostic accuracy of distance walked and oxygen saturation during the 6MWT in patients with IPF. We defined a new composite index, the distance-saturation product (DSP), which is the product of distance walked and lowest oxygen saturation during the 6-min walk test. We compared the performance of the DSP to the individual 6MWT parameters in predicting mortality.', 'We evaluated pulmonary function tests, 6-min walk parameters and the DSP between survivors and non-survivors. The ability of each measure to discriminate outcomes was determined by receiver operator curves.', '81 patients (48 survivors, 33 non-survivors) were included. Pulmonary function tests were similar and did not correlate with survival. Desaturation was greater (89.4% versus 83.7%, P<0.001) and distance walked was lower (406.9 versus 181.3m, P = 0.005) in non-survivors. The DSP was significantly lower among non-survivors (364.8 versus 153.5m%, P < 0.001) and predicted mortality more accurately than either individual 6MWT component (P = 0.035 versus desaturation, P=0.040 versus distance). A DSP <200 m% was associated with a seven-fold greater risk of 12-month mortality and an 18.0% shorter median survival compared with a DSP > 200 m% (P < 0.001).

Output: Does the distance-saturation product predict mortality in idiopathic pulmonary fibrosis?


Input: Consider Input: The aim of the study was to determine whether medial meniscal substitution with a polyurethane scaffold (Actifit(®)) improves the outcome of medial meniscal-deficient varus knees undergoing open-wedge high tibial osteotomy.', 'Sixty patients with symptomatic varus knees those who underwent open-wedge high tibial osteotomies were prospectively studied. In 30 patients, the medial meniscus was left with a defect larger than 25 mm (Group M). An Actifit(®) device was implanted (Group A) in the remaining 30 patients. Patients were functionally evaluated with WOMET, IKDC and VAS. Patient satisfaction was graded from 0 (not satisfied) to 4 (very satisfied).', 'Both groups were comparable preoperatively. They had similar follow-up periods (31.2 months; range 24-47.5; n.s.). WOMET improved a mean of 53.4 ± 8.4 and 42.4 ± 17.2 points in Groups M and A, respectively (p = 0.002). IKDC improved a mean of 56.7 ± 12 and 50.3 ± 15.6 points in Groups M and A, respectively (n.s.). VAS dropped 5.9 ± 2.1 and 4.7 ± 2.8 points in Groups M and A, respectively (p = 0.006). Patient satisfaction averaged 3.3 ± 0.8 and 3.3 ± 1 in Groups M and A, respectively (n.s.).

Output: Does partial meniscus substitution with a polyurethane scaffold improve outcome after an open-wedge high tibial osteotomy?


Input: Consider Input: Water channel aquaporin (AQP)-4 is expressed in Muller cells in retina, which are similar to astroglial cells in the central nervous system, where AQP4 deletion protects against cytotoxic brain edema after cerebral ischemia. A transient ischemia-reperfusion model was used to determine whether AQP4 deletion in mice protects the retina.', 'Retinal function and morphology were assessed in wild-type versus AQP4-deficient mice after ischemic damage produced by a 45- to 60-minute elevation of intraocular pressure to 120 mm Hg. Retinal function was assessed by electroretinography, and retinal structure by light microscopy. Extracellular space (ECS) size in fluorescently stained retinal slices was assessed by fluorescence recovery after photobleaching.', 'Retinal function and cell survival were significantly improved in AQP4-deficient mice in both inbred (C57/bl6) and outbred (CD1) genetic backgrounds. By electroretinography, b-wave amplitude was reduced by 75% to 83% at 1 to 4 days after ischemia in wild-type mice versus 48% to 51% in AQP4-null CD1 mice. Reductions were 53% to 72% versus <34% in C57/bl6 mice. Retinal structure and cell count were preserved in AQP4-null mice, particularly in the inner nuclear and plexiform layers of the retina, where Müller cells are concentrated. At 4 days after ischemia, inner retinal thickness was thinned by 43% in wild-type mice versus 11% in AQP4-null mice. Several mechanisms for retinal protection were investigated, including ECS expansion, reduced early swelling, and altered Kir4.1 K(+) channel expression.


Output: Does aquaporin-4 gene disruption in mice protect against impaired retinal function and cell death after ischemia?