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.

[Q]: Context: Old compared with young adults walk with reduced ankle and increased hip mechanical output. We examined the idea that age, leg strength, or both are related to the age-related changes in mechanical output during gait.', 'Healthy young (n = 32, age 21.5 years) and old adults (n = 32, age 76.8 years) participated in biomechanical gait analyses at 1.5 m/s and were also measured for maximal leg strength.', 'Analysis 1 confirmed previous data as old compared with young adults walked with 50 % more hip positive work and 18 % less ankle positive work. Analysis 2 showed that leg strength did not affect gait kinetics in groups of subjects with similar ages. In a weak young and a strong old group, Analysis 3 showed that old adults still walked with 23 % greater hip positive work. The group by joint interaction in Analysis 4 was suggestive of an even greater reliance on hip and less reliance on ankle work in weak compared with strong old adults.
Answer: Age and leg strength both contribute to the age-related changes in mechanical output during gait. Exercise prescription, normally targeting the knee extensors, should also involve ankle and hip muscles.
[A]: Do age and muscle strength mediate the age-related biomechanical plasticity of gait?


[Q]: Context: Alterations in epigenetic processes are frequently noted in human disease. These epigenetic processes involve methylation of DNA and post-translational modifications of histones. It is well established that in particular histone methylation plays a key role in gene transcription. In this study, we have investigated the relationship between triple methylation of lysine 27 in histone H3 (H3K27Me3) modifications and atherosclerotic plaque stage.', '28 peri-renal aortic tissue patches covering the entire spectrum of atherosclerotic plaque development were evaluated by immunohistochemistry for the levels of H3K27Me3, EZH2, JMJD3 and BMI1.', 'The results of our studies are in support of a reduction in global levels of the H3K27Me3 modification in vessels with advanced atherosclerotic plaques. This reduction in H3K27Me3 levels is not accompanied by alterations in global levels of the corresponding histone methyltransferase EZH2, the catalytic subunit of the polycomb repressive complex 2 (PRC2). Likewise no alterations in global levels of BMI1, a component of the PRC1 complex, which binds to H3K27Me3-modified histones or the global expression levels of the histone demethylase JMJD3, which removes the methyl marks on H3K27, were observed.
Answer: Together, our data show that in atherosclerosis development alterations in global levels of H3K27Me3 occur. The reduction in the number of nuclei in the tunica media that display the repressive H3K27Me3 mark in vessels with advanced atherosclerosis plaques therefore could be a reflection of the dynamic pattern of smooth muscle cell differentiation and proliferation associated with atherosclerotic disease.
[A]: Are global histone H3 lysine 27 triple methylation levels reduced in vessels with advanced atherosclerotic plaques?


[Q]: Context: The objective of this study is to compare the serum levels of Dickkopf-1 (DKK1), a natural inhibitor of Wnt signalling, with parathyroid hormone (PTH) and bone involvement in patients with rheumatoid arthritis (RA).', 'This cross-sectional study includes 154 postmenopausal women with RA and 125 healthy controls. DKK1, 25OH vitamin D (25OHD), bone turnover markers, and PTH serum levels were measured by ELISA; lumbar spine and hip bone mineral density (BMD) and the erosion score were obtained.', 'The RA patients and healthy controls were not significantly different in terms of age, body mass index, and 25OHD serum levels. The mean level of DKK1 and PTH were significantly higher in patients with RA than in healthy controls (172±68 [SD] vs. 96±55 pmoL/L, and 30±15 vs 22±11, respectively; p<0.0001). DKK1 serum levels were positively correlated with age (p<0.05) only in the healthy controls, while they were correlated with PTH serum levels only in the RA patients (p<0.0001). Among the RA patients, DKK1 levels adjusted for age, PTH and disease duration were significantly higher in patients with bone erosions (176 vs. 167 pmoL/L, respectively; p<0.05). DKK1 levels adjusted for age and PTH were negatively correlated with total hip BMD (p<0.05). In the RA patients not on treatment with bisphosphonates, DKK1 serum levels positively correlated with C-terminal telopeptides of type I collagene serum levels (p<0.05).
Answer: In patients with RA, serum levels of DKK1 are significantly increased, correlate with PTH and are associated with increased risk of bone erosions and osteoporosis. However, this finding deserves confirmation in a larger and more selected population.
[A]:
Are in patients with rheumatoid arthritis , Dickkopf-1 serum levels correlated with parathyroid hormone , bone erosions and bone mineral density?